Water Quality Standards; Establishment of Numeric Criteria for
Priority Toxic Pollutants for the State of California
[Federal Register: May 18, 2000 (Volume 65, Number 97)]
[Rules and Regulations]
[Page 31681-31719]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18my00-16]
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ENVIRONMENTAL PROTECTION AGENCY
40 CFR Part 131
[FRL-6587-9]
RIN 2040-AC44
Water Quality Standards; Establishment of Numeric Criteria for
Priority Toxic Pollutants for the State of California
AGENCY: Environmental Protection Agency.
ACTION: Final rule.
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SUMMARY: This final rule promulgates: numeric aquatic life criteria for
23 priority toxic pollutants; numeric human health criteria for 57
priority toxic pollutants; and a compliance schedule provision which
authorizes the State to issue schedules of compliance for new or
revised National Pollutant Discharge Elimination System permit limits
based on the federal criteria when certain conditions are met.
EPA is promulgating this rule based on the Administrator's
determination that numeric criteria are necessary in the State of
California to protect human health and the environment. The Clean Water
Act requires States to adopt numeric water quality criteria for
priority toxic pollutants for which EPA has issued criteria guidance,
the presence or discharge of which could reasonably be expected to
interfere with maintaining designated uses.
EPA is promulgating this rule to fill a gap in California water
quality standards that was created in 1994 when a State court
overturned the State's water quality control plans which contained
water quality criteria for priority toxic pollutants. Thus, the State
of California has been without numeric water quality criteria for many
priority toxic pollutants as required by the Clean Water Act,
necessitating this action by EPA. These Federal criteria are legally
applicable in the State of California for inland surface waters,
enclosed bays and estuaries for all purposes and programs under the
Clean Water Act.
EFFECTIVE DATE: This rule shall be effective May 18, 2000.
ADDRESSES: The administrative record for today's final rule is
available for public inspection at the U.S. Environmental Protection
Agency, Region 9, Water Division, 75 Hawthorne Street, San Francisco,
California 94105, between the hours of 8:00 a.m. and 4:30 p.m. For
access to the administrative record, call Diane E. Fleck, P.E., Esq. at
415 744-1984 for an appointment. A reasonable fee will be charged for
photocopies.
FOR FURTHER INFORMATION CONTACT: Diane E. Fleck, P.E., Esq. or Philip
Woods, U.S. Environmental Protection Agency, Region 9, Water Division,
75 Hawthorne Street, San Francisco, California 94105, 415-744-1984 or
415-744-1997, respectively.
SUPPLEMENTARY INFORMATION: This preamble is organized according to the
following outline:
A. Potentially Affected Entities
B. Introduction and Overview
1. Introduction
2. Overview
C. Statutory and Regulatory Background
D. California Water Quality Standards Actions
1. California Regional Water Quality Control Board Basin Plans, and
the Inland Surface Waters Plan (ISWP) and the Enclosed Bays and
Estuaries Plan (EBEP) of April 1991
2. EPA's Review of California Water Quality Standards for Priority
Toxic Pollutants in the ISWP and EBEP, and the National Toxics Rule
3. Status of Implementation of CWA Section 303(c)(2)(B)
4. State-Adopted, Site-Specific Criteria for Priority Toxic
Pollutants
a. State-Adopted Site-Specific Criteria Under EPA Review
b. State-Adopted Site-Specific Criteria With EPA Approval
E. Rationale and Approach For Developing the Final Rule
1. Legal Basis
2. Approach for Developing this Rule
F. Derivation of Criteria
1. Section 304(a) Criteria Guidance Process
2. Aquatic Life Criteria
a. Freshwater Acute Selenium Criterion
b. Dissolved Metals Criteria
c. Application of Metals Criteria
d. Saltwater Copper Criteria
e. Chronic Averaging Period
f. Hardness
3. Human Health Criteria
a. 2,3,7,8-TCDD (Dioxin) Criteria
b. Arsenic Criteria
c. Mercury Criteria
d. Polychlorinated Biphenyls (PCBs) Criteria
e. Excluded Section 304(a) Human Health Criteria
f. Cancer Risk Level
G. Description of Final Rule
1. Scope
2. EPA Criteria for Priority Toxic Pollutants
3. Implementation
4. Wet Weather Flows
5. Schedules of Compliance
6. Changes from Proposed Rule
H. Economic Analysis
1. Costs
2. Benefits
I. Executive Order 12866, Regulatory Planning and Review
J. Unfunded Mandates Reform Act of 1995
K. Regulatory Flexibility Act
L. Paperwork Reduction Act
M. Endangered Species Act
N. Congressional Review Act
O. Executive Order 13084, Consultation and Coordination With Indian
Tribal Governments
P. National Technology Transfer and Advancement Act
Q. Executive Order 13132 on Federalism
R. Executive Order 13045 on Protection of Children From
Environmental Health Risks and Safety Risks
A. Potentially Affected Entities
Citizens concerned with water quality in California may be
interested in this rulemaking. Entities discharging pollutants to
waters of the United States in California could be affected by this
rulemaking since water quality criteria are used by the State in
developing National Pollutant Discharge Elimination System (NPDES)
permit limits. Categories and entities that ultimately may be affected
include:
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Category Examples of potentially affected entities
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Industry..................... Industries discharging pollutants to
surface waters in California or to
publicly-owned treatment works.
Municipalities............... Publicly-owned treatment works
discharging pollutants to surface waters
in California
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This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by this
action. This table lists the types of entities that EPA is now aware
could potentially be affected by this action. Other types of entities
not listed in the table could also be affected. To determine whether
your facility might be affected by this action, you should carefully
examine the applicability criteria in Sec. 131.38(c). If you have
questions regarding the applicability of this action to a particular
entity, consult the persons listed in the preceding FOR FURTHER
INFORMATION CONTACT section.
[[Page 31683]]
B. Introduction and Overview
1. Introduction
This section introduces the topics which are addressed in the
preamble and provides a brief overview of EPA's basis and rationale for
promulgating Federal criteria for the State of California. Section C
briefly describes the evolution of the efforts to control toxic
pollutants; these efforts include the changes enacted in the 1987 CWA
Amendments, which are the basis for this rule. Section D summarizes
California's efforts since 1987 to implement the requirements of CWA
section 303(c)(2)(B) and describes EPA's procedure and actions for
determining whether California has fully implemented CWA section
303(c)(2)(B). Section E provides the rationale and approach for
developing this final rule, including a discussion of EPA's legal basis
for this final rule. Section F describes the development of the
criteria included in this rule. Section G summarizes the provisions of
the final rule and discusses implementation issues. Sections H, I, J, K
, L, M, N, O, P, and Q briefly address the requirements of Executive
Order 12866, the Unfunded Mandates Reform Act of 1995, the Regulatory
Flexibility Act, the Paperwork Reduction Act, the Endangered Species
Act, the Congressional Review Act, Executive Order 13084, Consultation
and Coordination with Indian Tribal Governments, the National
Technology Transfer and Advancement Act, and Executive Order 13132,
Federalism, respectively.
The proposal for this rulemaking was published in the Federal
Register on August 5, 1997. Changes from the proposal are generally
addressed in the body of this preamble and specifically addressed in
the response to comments document included in the administrative record
for this rulemaking. EPA responded to all comments on the proposed
rule, including comments received after the September 26, 1997,
deadline. Although EPA is under no legal obligation to respond to late
comments, EPA made a policy decision to respond to all comments.
Since detailed information concerning many of the topics in this
preamble was published previously in the Federal Register in preambles
for this and other rulemakings, references are frequently made to those
preambles. Those rulemakings include: Water Quality Standards;
Establishment of Numeric Criteria for Priority Toxic Pollutants for the
State of California; Proposed Rule, 62 FR 42159, August 5, 1997
(referred to as the ``proposed CTR''); Water Quality Standards;
Establishment of Numeric Criteria for Priority Toxic Pollutants, 57 FR
60848, December 22, 1992 (referred to as the ``National Toxics Rule''
or ``NTR''); and the NTR as amended by Administrative Stay of Federal
Water Quality Criteria for Metals and Interim Final Rule, Water Quality
Standards; Establishment of Numeric Criteria for Priority Toxic
Pollutants; States' Compliance--Revision of Metals Criteria, 60 FR
22228, May 4, 1995 (referred to as the ``National Toxics Rule [NTR], as
amended''). The NTR, as amended, is codified at 40 CFR 131.36. A copy
of the proposed CTR and its preamble, and the NTR, as amended, and its
preambles are contained in the administrative record for this
rulemaking.
EPA is making this final rule effective upon publication. Under the
Administrative Procedure Act, 5 U.S.C. 553(d)(3), agencies must
generally publish a rule no more than 30 days prior to the effective
date of the rule except as otherwise provided for by the Agency for
good cause. The purpose of the 30-day waiting period is to give
affected parties a reasonable time to adjust their behavior before the
final rule takes effect. See Omnipoint Corp. v. F.C.C., 78 F.3d 620,
630-631 (D.C. Cir. 1996); Riverbend Farms, Inc. v. Madigan, 958 F.2d
1479, 1485 (9th Cir. 1992).
In this instance, EPA finds good cause to make the final rule
effective upon publication. In order to find good cause, an Agency
needs to find that the 30-day period would be: (1) Impracticable, (2)
unnecessary, or (3) contrary to the public interest. Here EPA is
relying on the second reason to support its finding of good cause. EPA
also notes that the State has requested EPA to make the rule
immediately effective.
EPA finds that in this instance, waiting 30 days to make the rule
effective is unnecessary. As explained in further detail elsewhere in
this preamble, this rule is not self implementing; rather it
establishes ambient conditions that the State of California will
implement in future permit proceedings. These permit proceedings will,
by regulation, take longer than 30 days to complete. This means that
although the rule is immediately effective, no discharger's conduct
would be altered under the rule in less than 30 days, and therefore the
30-day period is unnecessary.
2. Overview
This final rule establishes ambient water quality criteria for
priority toxic pollutants in the State of California. The criteria in
this final rule will supplement the water quality criteria promulgated
for California in the NTR, as amended. In 1991, EPA approved a number
of water quality criteria (discussed in section D), for the State of
California. Since EPA had approved these criteria, it was not necessary
to include them in the 1992 NTR for these criteria. However, the EPA-
approved criteria were subsequently invalidated in State litigation.
Thus, this final rule contains criteria to fill the gap created by the
State litigation.
This final rule does not change or supersede any criteria
previously promulgated for the State of California in the NTR, as
amended. Criteria which EPA promulgated for California in the NTR, as
amended, are footnoted in the final table at 131.38(b)(1), so that
readers may see the criteria promulgated in the NTR, as amended, for
California and the criteria promulgated through this rulemaking for
California in the same table. This final rule is not intended to apply
to waters within Indian Country. EPA recognizes that there are possibly
waters located wholly or partly in Indian Country that are included in
the State's basin plans. EPA will work with the State and Tribes to
identify any such waters and determine whether further action to
protect water quality in Indian Country is necessary.
This rule is important for several environmental, programmatic and
legal reasons. Control of toxic pollutants in surface waters is
necessary to achieve the CWA's goals and objectives. Many of
California's monitored river miles, lake acres, and estuarine waters
have elevated levels of toxic pollutants. Recent studies on California
water bodies indicate that elevated levels of toxic pollutants exist in
fish tissue which result in fishing advisories or bans. These toxic
pollutants can be attributed to, among other sources, industrial and
municipal discharges.
Water quality standards for toxic pollutants are important to State
and EPA efforts to address water quality problems. Clearly established
water quality goals enhance the effectiveness of many of the State's
and EPA's water programs including permitting, coastal water quality
improvement, fish tissue quality protection, nonpoint source controls,
drinking water quality protection, and ecological protection. Numeric
criteria for toxic pollutants allow the State and EPA to evaluate the
adequacy of existing and potential control measures to protect aquatic
ecosystems and human health. Numeric criteria also provide a more
precise basis for deriving water quality-based effluent limitations
(WQBELs) in
[[Page 31684]]
National Pollutant Discharge Elimination System (NPDES) permits and
wasteload allocations for total maximum daily loads (TMDLs) to control
toxic pollutant discharges. Congress recognized these issues when it
enacted section 303(c)(2)(B) to the CWA.
While California recognizes the need for applicable water quality
standards for toxic pollutants, its adoption efforts have been stymied
by a variety of factors. The Administrator has decided to exercise her
CWA authorities to move forward the toxic control program, consistent
with the CWA and with the State of California's water quality standards
program.
Today's action will also help restore equity among the States. The
CWA is designed to ensure all waters are sufficiently clean to protect
public health and/or the environment. The CWA allows some flexibility
and differences among States in their adopted and approved water
quality standards, but it should be implemented in a manner that
ensures a level playing field among States. Although California has
made important progress toward satisfying CWA requirements, it has not
satisfied CWA section 303(c)(2)(B) by adopting numeric water quality
criteria for toxic pollutants. This section was added to the CWA by
Congress in 1987. Prior to today, the State of California had been the
only State in the Nation for which CWA section 303(c)(2)(B) had
remained substantially unimplemented after EPA's promulgation of the
NTR in December of 1992. Section 303(c)(4) of the CWA authorizes the
EPA Administrator to promulgate standards where necessary to meet the
requirements of the Act. The Administrator determined that this rule
was a necessary and important component for the implementation of CWA
section 303(c)(2)(B) in California.
EPA acknowledges that the State of California is working to satisfy
CWA section 303(c)(2)(B). When the State formally adopts, and EPA
approves, criteria consistent with statutory requirements, as
envisioned by Congress in the CWA, EPA intends to stay this rule. If
within the applicable time frame for judicial review, the States'
standards are challenged, EPA will withdraw this rule after such
judicial review is complete and the State standards are sustained.
C. Statutory and Regulatory Background
The preamble to the August 5, 1997, proposed rule provided a
general discussion of EPA's statutory and regulatory authority to
promulgate water quality criteria for the State of California. See 62
FR 42160-42163. EPA is including that discussion in the record for the
final rule. Commenters questioned EPA's authority to promulgate certain
aspects of the proposal. EPA is responding to those comments in the
appropriate sections of this preamble, and in the response to comments
document included in the administrative record for this rulemaking.
Where appropriate, EPA's responses expand upon the discussion of
statutory and regulatory authority found in the proposal.
D. California Water Quality Standards Actions
1. California Regional Water Quality Control Board Basin Plans, and the
Inland Surface Waters Plan (ISWP) and the Enclosed Bays and Estuaries
Plan (EBEP) of April 1991
The State of California regulates water quality through its State
Water Resources Control Board (SWRCB) and through nine Regional Water
Quality Control Boards (RWQCBs). Each of the nine RWQCBs represents a
different geographic area; area boundaries are generally along
watershed boundaries. Each RWQCB maintains a Basin Plan which contains
the designated uses of the water bodies within its respective
geographic area within California. These designated uses (or
``beneficial uses'' under State law) together with legally-adopted
criteria (or ``objectives'' under State law), comprise water quality
standards for the water bodies within each of the Basin areas. Each of
the nine RWQCBs undergoes a triennial basin planning review process, in
compliance with CWA section 303. The SWRCB provides assistance to the
RWQCBs.
Most of the Basin Plans contain conventional pollutant objectives
such as dissolved oxygen. None of the Basin Plans contains a
comprehensive list of priority toxic pollutant criteria to satisfy CWA
section 303(c)(2)(B). The nine RWQCBs and the SWRCB had intended that
the priority toxic pollutant criteria contained in the three SWRCB
statewide plans, the Inland Surface Waters Plan (ISWP), the Enclosed
Bays and Estuaries Plan (EBEP), and the Ocean Plan, apply to all basins
and satisfy CWA section 303(c)(2)(B).
On April 11, 1991, the SWRCB adopted two statewide water quality
control plans, the ISWP and the EBEP. These statewide plans contained
narrative and numeric water quality criteria for toxic pollutants, in
part to satisfy CWA section 303(c)(2)(B). The water quality criteria
contained in the SWRCB statewide plans, together with the designated
uses in each of the Basin Plans, created a set of water quality
standards for waters within the State of California.
Specifically, the two plans established water quality criteria or
objectives for all fresh waters, bays and estuaries in the State. The
plans contained water quality criteria for some priority toxic
pollutants, provisions relating to whole effluent toxicity,
implementation procedures for point and nonpoint sources, and
authorizing compliance schedule provisions. The plans also included
special provisions affecting waters dominated by reclaimed water
(labeled as Category (a) waters), and waters dominated by agricultural
drainage and constructed agricultural drains (labeled as Category (b)
and (c) waters, respectively).
2. EPA's Review of California Water Quality Standards for Priority
Toxic Pollutants in the ISWP and EBEP, and the National Toxics Rule
The EPA Administrator has delegated the responsibility and
authority for review and approval or disapproval of all new or revised
State water quality standards to the EPA Regional Administrators (see
40 CFR 131.21). Thus, State actions under CWA section 303(c)(2)(B) are
submitted to the appropriate EPA Regional Administrator for review and
approval.
In mid-April 1991, the SWRCB submitted to EPA for review and
approval the two statewide water quality control plans, the ISWP and
the EBEP. On November 6, 1991, EPA Region 9 formally concluded its
review of the SWRCB's plans. EPA approved the narrative water quality
criterion and the toxicity criterion in each of the plans. EPA also
approved the numeric water quality criteria contained in both plans,
finding them to be consistent with the requirements of section
303(c)(2)(B) of the CWA and with EPA's national criteria guidance
published pursuant to section 304(a) of the CWA.
EPA noted the lack of criteria for some pollutants, and found that,
because of the omissions, the plans did not fully satisfy CWA section
303(c)(2)(B). The plans did not contain criteria for all listed
pollutants for which EPA had published national criteria guidance. The
ISWP contained human health criteria for only 65 pollutants, and the
EBEP contained human health criteria for only 61 pollutants for which
EPA had issued section 304(a) guidance criteria. Both the ISWP and EBEP
contained aquatic life criteria for all pollutants except cyanide and
chromium III (freshwater only) for which EPA has CWA section
[[Page 31685]]
304(a) criteria guidance. The SWRCB's administrative record stated that
all priority pollutants with EPA criteria guidance were likely to be
present in California waters. However, the SWRCB's record contained
insufficient information to support a finding that the excluded
pollutants were not reasonably expected to interfere with designated
uses of the waters of the State.
Although EPA approved the statewide selenium objective in the ISWP
and EBEP, EPA disapproved the objective for the San Francisco Bay and
Delta, because there was clear evidence that the objective would not
protect the designated fish and wildlife uses (the California
Department of Health Services had issued waterfowl consumption
advisories due to selenium concentrations, and scientific studies had
documented selenium toxicity to fish and wildlife). EPA restated its
commitment to object to National Pollutant Discharge Elimination System
(NPDES) permits issued for San Francisco Bay that contained effluent
limits based on an objective greater than 5 parts per billion (ppb)
(four day average) and 20 ppb (1 hour average), the freshwater
criteria. EPA reaffirmed its disapproval of Californias' site-specific
selenium objective for portions of the San Joaquin River, Salt Slough,
and Mud Slough. EPA also disapproved of the categorical deferrals and
exemptions. These disapprovals included the disapproval of the State's
deferral of water quality objectives to effluent dominated streams
(Category a) and to streams dominated by agricultural drainage
(Category b), and the disapproval of the exemption of water quality
objectives to constructed agricultural drains (Category c). EPA found
the definitions of the categories imprecise and overly broad which
could have led to an incorrect interpretation.
Since EPA had disapproved portions of each of the California
statewide plans which were necessary to satisfy CWA section
303(c)(2)(B), certain disapproved aspects of California's water quality
standards were included in EPA's promulgation of the National Toxics
Rule (NTR) (40 CFR 131.36, 57 FR 60848). EPA promulgated specific
criteria for certain water bodies in California.
The NTR was amended, effective April 14, 1995, to stay certain
metals criteria which had been promulgated as total recoverable.
Effective April 15, 1995, EPA promulgated interim final metals criteria
as dissolved concentrations for those metals which had been stayed
(Administrative Stay of Federal Water Quality Criteria for Metals and
Interim Final Rule, Water Quality Standards; Establishment of Numeric
Criteria for Priority Toxic Pollutants; States' Compliance--Revision of
Metals Criteria; 60 FR 22228, 22229, May 4, 1995 [the NTR, as
amended]). The stay was in response to a lawsuit against EPA
challenging, among other issues, metals criteria expressed as total
recoverable concentrations. A partial Settlement Agreement required EPA
to stay specific metals criteria in the NTR. EPA then promulgated
certain metals criteria in the dissolved form through the use of
conversion factors. These factors are listed in the NTR, as amended. A
scientific discussion of these criteria is found in a subsequent
section of this preamble.
Since certain criteria have already been promulgated for specific
water bodies in the State of California in the NTR, as amended, they
are not within the scope of today's final rule. However, for clarity in
reading a comprehensive rule for the State of California, these
criteria are incorporated into 40 CFR 131.38(d)(2). Footnotes to the
Table in 40 CFR 131.38(b)(1) and 40 CFR 131.38(d)(3) clarify which
criteria (and for which specific water bodies) were promulgated by the
NTR, as amended, and are therefore excluded from this final rule. The
appropriate (freshwater or saltwater) aquatic life criteria which were
promulgated in the NTR, as amended, for all inland surface waters and
enclosed bays and estuaries include: chromium III and cyanide. The
appropriate (water and organism or organism only) human health criteria
which were promulgated in the NTR, as amended, for all inland surface
waters and enclosed bays and estuaries include:
antimony
thallium
asbestos
acrolein
acrylonitrile
carbon tetrachloride
chlorobenzene
1,2-dichloroethane
1,1-dichloroethylene
1,3-dichloropropylene
ethylbenzene
1,1,2,2-tetrachloroethane
tetrachloroethylene
1,1,2-trichloroethane
trichloroethylene
vinyl chloride
2,4-dichlorophenol
2-methyl-4,6-dinitrophenol
2,4-dinitrophenol
benzidine
bis(2-chloroethyl)ether
bis(2-ethylhexyl)phthalate
3,3-dichlorobenzidine
diethyl phthalate
dimethyl phthalate
di-n-butyl phthalate
2,4-dinitrotoluene
1,2-diphenylhydrazine
hexachlorobutadiene
hexachlorocyclopentadiene
hexachloroethane
isophorone
nitrobenzene
n-nitrosodimethylamine
n-nitrosodiphenylamine
Other pollutant criteria were promulgated in the NTR, as amended,
for specific water bodies, but not all inland surface waters and
enclosed bays and estuaries.
3. Status of Implementation of CWA Section 303(c)(2)(B)
Shortly after the SWRCB adopted the ISWP and EBEP, several
dischargers filed suit against the State alleging that it had not
adopted the two plans in compliance with State law. The plaintiffs in a
consolidated case included: the County of Sacramento, Sacramento County
Water Agency; Sacramento Regional County Sanitation District; the City
of Sacramento; the City of Sunnyvale; the City of San Jose; the City of
Stockton; and Simpson Paper Company.
The dischargers alleged that the State had not adopted the ISWP and
EBEP in compliance with the California Administrative Procedures Act
(Gov Code. Section 11340, et seq.), the California Environmental
Quality Act (Pub. Re Code, Section 21000, et seq.), and the Porter-
Cologne Act (Wat. Code, Section 13200, et seq.). The allegation that
the State did not sufficiently consider economics when adopting water
quality objectives, as allegedly required by Section 13241 of the
Porter Cologne Act, was an important issue in the litigation.
In October of 1993, the Superior Court of California, County of
Sacramento, issued a tentative decision in favor of the dischargers. In
March of 1994, the Court issued a substantively similar final decision
in favor of the dischargers. Final judgments from the Court in July of
1994 ordered the SWRCB to rescind the ISWP and EBEP. On September 22,
1994, the SWRCB formally rescinded the two statewide water quality
control plans. The State is currently in the process of readopting
water quality control plans for inland surface waters, enclosed bays
and estuaries.
CWA section 303(c)(2)(B) was fully implemented in the State of
California from December of 1992, when the NTR was promulgated, until
September of 1994, when the SWRCB was required to rescind the ISWP and
EBEP. The provisions for California in EPA's NTR together with the
approved portions of
[[Page 31686]]
California's ISWP and EBEP implemented the requirements of CWA section
303(c)(2)(B). However, since September of 1994, when the SWRCB
rescinded the ISWP and EBEP, the requirements of section 303(c)(2)(B)
have not been fully implemented in California.
The scope of today's rule is to re-establish criteria for the
remaining priority toxic pollutants to meet the requirements of section
303(c)(2)(B) of the CWA. Pursuant to section 303(c)(4), the
Administrator has determined that it is necessary to include in today's
action criteria for priority toxic pollutants, which are not covered by
the NTR, as amended, or by the State through EPA-approved site-specific
criteria, for waters of the United States in the State of California.
4. State-Adopted, Site-Specific Criteria for Priority Toxic Pollutants
The State has the discretion to develop site-specific criteria when
appropriate e.g., when statewide criteria appear over-or under-
protective of designated uses. Periodically, the State through its
RWQCBs will adopt site-specific criteria for priority toxic pollutants
within respective Basin Plans. These criteria are intended to be
effective throughout the Basin or throughout a designated water body.
Under California law, these criteria must be publicly reviewed and
approved by the RWQCB, the SWRCB, and the State's Office of
Administrative Law (OAL). Once this adoption process is complete, the
criteria become State law.
These criteria must be submitted to the EPA Regional Administrator
for review and approval under CWA section 303. These criteria are
usually submitted to EPA as part of a RWQCB Basin Plan Amendment, after
the Amendment has been adopted under the State's process and has become
State law.
a. State-Adopted Site-Specific Criteria Under EPA Review
The State of California has recently reviewed and updated all of
its RWQCB Basin Plans. All of the Basin Plans have completed the State
review and adoption process and have been submitted to EPA for review
and approval. Some of the Basin Plans contain site-specific criteria.
In these cases, the State-adopted site-specific criteria are used for
water quality programs.
EPA has not yet concluded consultation under the Endangered Species
Act with the U.S. Department of Interior, Fish and Wildlife Service,
and the U.S. Department of Commerce, National Marine Fisheries Service,
on EPA's tentative approval/disapproval actions on the RWQCB Basin
Plans. In this situation, the more stringent of the two criteria (the
State-adopted site-specific criteria in the RWQCB Basin Plans, or the
Federal criteria in this final rule), would be used for water quality
programs including the calculation of water quality-based effluent
criteria in National Pollutant Discharge Elimination System (NPDES)
permits.
b. State-Adopted Site-Specific Criteria With EPA Approval
In several cases, the EPA Regional Administrator has already
reviewed and approved State-adopted site-specific criteria within the
State of California. Several of these cases are discussed in this
section. All of the EPA approval letters referenced in today's preamble
are contained in the administrative record for today's rule.
Sacramento River: EPA has approved site-specific acute criteria for
copper, cadmium and zinc in the Sacramento River, upstream of Hamilton
City, in the Central Valley Region (RWQCB for the Central Valley
Region) of the State of California. EPA approved these site-specific
criteria by letter dated August 7, 1985. Specifically, EPA approved for
the Sacramento River (and tributaries) above Hamilton City, a copper
criterion of 5.6 µg/l (maximum), a zinc criterion of 16
µg/l (maximum) and a cadmium criterion of 0.22 µg/l
(maximum), all in the dissolved form using a hardness of 40 mg/l as
CaCO3. (These criteria were actually adopted by the State and approved
by EPA as equations which vary with hardness.) These ``maximum''
criteria correspond to acute criteria in today's final rule. Therefore,
Federal acute criteria for copper, cadmium, and zinc for the Sacramento
River (and tributaries) above Hamilton City are not necessary to
protect the designated uses and are not included in the final rule.
However, the EPA Administrator is making a finding that it is necessary
to include chronic criteria for copper, cadmium and zinc for the
Sacramento River (and tributaries) above Hamilton City, as part of the
statewide criteria promulgated in today's final rule.
San Joaquin River: The selenium criteria in this rule are not
applicable to portions of the San Joaquin River, in the Central Valley
Region, because selenium criteria have been either previously approved
by EPA or previously promulgated by EPA as part of the NTR. EPA
approved and disapproved State-adopted site-specific selenium criteria
in portions of the San Joaquin River, in the Central Valley Region of
the State of California (RWQCB for the Central Valley Region). EPA's
determination on these site-specific criteria is contained in a letter
dated April 13, 1990.
Specifically, EPA approved for the San Joaquin River, mouth of
Merced River to Vernalis, an aquatic life selenium criterion of 12
µg/l (maximum with the understanding that the instantaneous
maximum concentration may not exceed the objective more than once every
three years). Today's final rule does not affect this Federally-
approved, State-adopted site-specific acute criterion, and it remains
in effect for the San Joaquin River, mouth of Merced River to Vernalis.
Therefore, an acute criterion for selenium in the San Joaquin River,
mouth of Merced River to Vernalis is not necessary to protect the
designated use and thus is not included in this final rule.
By letter dated April 13, 1990, EPA also approved for the San
Joaquin River, mouth of Merced River to Vernalis, a State-adopted site-
specific aquatic life selenium criterion of 5 µg/l (monthly
mean); however, EPA disapproved a State-adopted site-specific selenium
criterion of 8 µg/l (monthly mean--critical year only) for
these waters. Subsequently, EPA promulgated a chronic selenium
criterion of 5 µg/l (4 day average) for waters of the San
Joaquin River from the mouth of the Merced River to Vernalis in the
NTR. This chronic criterion applies to all water quality programs
concerning the San Joaquin River, mouth of Merced River to Vernalis.
Today's final rule does not affect the Federally-promulgated chronic
selenium criterion of 5 µg/l (4 day average) set forth in the
NTR. This previously Federally-promulgated criterion remains in effect
for the San Joaquin River, mouth of Merced River to Vernalis.
Grassland Water District, San Luis National Wildlife Refuge, and
Los Banos State Wildlife Refuge: EPA approved for the Grassland Water
District, San Luis National Wildlife Refuge, and Los Banos State
Wildlife Refuge, a State-adopted site-specific aquatic life selenium
criterion of 2 µg/l (monthly mean) by letter dated April 13,
1990. This Federally-approved, State-adopted site-specific chronic
criterion remains in effect for the Grassland Water District, San Luis
National Wildlife Refuge and Los Banos State Wildlife Refuge. Therefore
it is not necessary to include in today's final rule, a chronic
criterion for selenium for the Grassland Water District, San Luis
National Wildlife Refuge and Los Banos State Wildlife Refuge, and thus,
it is not included in this final rule.
[[Page 31687]]
San Francisco Regional Board Basin Plan of 1986: EPA approved
several priority toxic pollutant objectives (CWA criteria) that were
contained in the1986 San Francisco Regional Board Basin Plan, as
amended by SWRCB Resolution Numbers 87-49, 87-82 and 87-92, by letters
dated September 2, 1987 and December 24, 1987. This Basin Plan, the
SWRCB Resolutions, and the EPA approval letters are contained in the
administrative record for this rulemaking. It is not necessary to
include these criteria for priority toxic pollutants that are contained
in the San Francisco Regional Board's 1986 Basin Plan as amended, and
approved by EPA. Priority pollutants in this situation are footnoted in
the matrix at 131.38(b)(1) with footnote ``b.'' Where gaps exist in the
State adoption and EPA approval of priority toxic pollutant objectives,
the criteria in today's rule apply.
EPA is assigning ``human health, water and organism consumption''
criteria to waters with the States' municipal or ``MUN'' beneficial use
designation in the Basin Plan. Also, some pollutants regulated through
the Basin Plan have different averaging periods, e.g., one hour as
compared with the rule's ``short-term.'' However, where classes of
chemicals, such as polynuclear aromatic hydrocarbons, or PAHs, and
phenols, are regulated through the Basin Plan, but not specific
chemicals within the category, specific chemicals within the category
are regulated by today's rule.
E. Rationale and Approach for Developing the Final Rule
This section explains EPA's legal basis for today's final rule, and
discusses EPA's general approach for developing the specific
requirements for the State of California.
1. Legal Basis
CWA section 303(c) specifies that adoption of water quality
standards is primarily the responsibility of the States. However, CWA
section 303(c) also describes a role for the Federal government to
oversee State actions to ensure compliance with CWA requirements. If
EPA's review of the States' standards finds flaws or omissions, then
the CWA authorizes EPA to correct the deficiencies (see CWA section
303(c)(4)). This water quality standards promulgation authority has
been used by EPA to issue final rules on several separate occasions,
including the NTR, as amended, which promulgated criteria similar to
those included here for a number of States. These actions have
addressed both insufficiently protective State criteria and/or
designated uses and failure to adopt needed criteria. Thus, today's
action is not unique.
The CWA in section 303(c)(4) provides two bases for promulgation of
Federal water quality standards. The first basis, in paragraph (A),
applies when a State submits new or revised standards that EPA
determines are not consistent with the applicable requirements of the
CWA. If, after EPA's disapproval, the State does not amend its rules so
as to be consistent with the CWA, EPA is to promptly propose
appropriate Federal water quality standards for that State. The second
basis for an EPA action is in paragraph (B), which provides that EPA
shall promptly initiate promulgation ``* * * in any case where the
Administrator determines that a revised or new standard is necessary to
meet the requirements of this Act.'' EPA is using section 303(c)(4)(B)
as the legal basis for today's final rule.
As discussed in the preamble to the NTR, the Administrator's
determination under CWA section 303(c)(4) that criteria are necessary
to meet the requirements of the Act could be supported in several ways.
Consistent with EPA's approach in the NTR, EPA interprets section
303(c)(2)(B) of the CWA to allow EPA to act where the State has not
succeeded in establishing numeric water quality standards for toxic
pollutants. This inaction can be the basis for the Administrator's
determination under section 303(c)(4) that new or revised criteria are
necessary to ensure designated uses are protected.
EPA does not believe that it is necessary to support the criteria
in today's rule on a pollutant-specific, water body-by-water-body
basis. For EPA to undertake an effort to conduct research and studies
of each stream segment or water body across the State of California to
demonstrate that for each toxic pollutant for which EPA has issued CWA
section 304(a) criteria guidance there is a ``discharge or presence''
of that pollutant which could reasonably ``be expected to interfere
with'' the designated use would impose an enormous administrative
burden and would be contrary to the statutory directive for swift
action manifested by the 1987 addition of section 303(c)(2)(B) to the
CWA. Moreover, because these criteria are ambient criteria that define
attainment of the designated uses, their application to all water
bodies will result in additional controls on dischargers only where
necessary to protect the designated uses.
EPA's interpretation of section 303(c)(2)(B) is supported by the
language of the provision, the statutory framework and purpose of
section 303, and the legislative history. In adding section
303(c)(2)(B) to the CWA, Congress understood the existing requirements
in section 303(c)(1) for States to conduct triennial reviews of their
water quality standards and submit the results of those reviews to EPA
and in section 303(c)(4)(B) for promulgation. CWA section 303(c)
includes numerous deadlines and section 303(c)(4) directs the
Administrator to act ``promptly'' where the Administrator determines
that a revised or new standard is necessary to meet the requirements of
the Act. Congress, by linking section 303(c)(2)(B) to the section
303(c)(1) three-year review period, gave States a last chance to
correct this deficiency on their own. The legislative history of the
provision demonstrates that chief Senate sponsors, including Senators
Stafford, Chaffee and others wanted the provision to eliminate State
and EPA delays and force quick action. Thus, to interpret CWA section
303(c)(2)(B) and (c)(4) to require such a cumbersome pollutant specific
effort on each stream segment would essentially render section
303(c)(2)(B) meaningless. The provision and its legislative background
indicate that the Administrator's determination to invoke section
303(c)(4)(B) authority can be met by the Administrator making a generic
finding of inaction by the State without the need to develop pollutant
specific data for individual stream segments. Finally, the reference in
section 303(c)(2)(B) to section 304(a) criteria suggests that section
304(a) criteria serve as default criteria; that once EPA has issued
them, States were to adopt numeric criteria for those pollutants based
on the 304(a) criteria, unless they had other scientifically defensible
criteria. EPA also notes that this rule follows the approach EPA took
nationally in promulgating the NTR for States that failed to comply
with CWA section 303(c)(2)(B). 57 FR 60848, December 22, 1992. EPA
incorporates the discussion in the NTR preamble as part of this
rulemaking record.
This determination is supported by information in the rulemaking
record showing the discharge or presence of priority toxic pollutants
throughout the State. While this data is not necessarily complete, it
constitutes a strong record supporting the need for numeric criteria
for priority toxic pollutants with section 304(a) criteria guidance
where the State does not have numeric criteria.
Today's final rule would not impose any undue or inappropriate
burden on the State of California or its dischargers. It merely puts in
place numeric criteria
[[Page 31688]]
for toxic pollutants that are already used in other States in
implementing CWA programs. Under this rulemaking, the State of
California retains the ability to adopt alternative water quality
criteria simply by completing its criteria adoption process. Upon EPA
approval of those criteria, EPA will initiate action to stay the
Federally-promulgated criteria and subsequently withdraw them.
2. Approach for Developing This Rule
In summary, EPA developed the criteria promulgated in today's final
rule as follows. Where EPA promulgated criteria for California in the
NTR, EPA has not acted to amend the criteria in the NTR. Where criteria
for California were not included in the NTR, EPA used section 304(a)
National criteria guidance documents as a starting point for the
criteria promulgated in this rule. EPA then determined whether new
information since the development of the national criteria guidance
documents warranted any changes. New information came primarily from
two sources. For human health criteria, new or revised risk reference
doses and cancer potency factors on EPA's Integrated Risk Information
System (IRIS) as of October 1996 form the basis for criteria values
(see also 63 FR 68354). For aquatic life criteria, updated data sets
resulting in revised criteria maximum concentrations (CMCs) and
criteria continuous concentrations (CCCs) formed the basis for
differences from the national criteria guidance documents. Both of
these types of changes are discussed in more detail in the following
sections. This revised information was used to develop the water
quality criteria promulgated here for the State of California.
F. Derivation of Criteria
1. Section 304(a) Criteria Guidance Process
Under CWA section 304(a), EPA has developed methodologies and
specific criteria guidance to protect aquatic life and human health.
These methodologies are intended to provide protection for all surface
waters on a national basis. The methodologies have been subject to
public review, as have the individual criteria guidance documents.
Additionally, the methodologies have been reviewed by EPA's Science
Advisory Board (SAB) of external experts.
EPA has included in the record of this rule the aquatic life
methodology as described in ``Appendix B--Guidelines for Deriving Water
Quality Criteria for the Protection of Aquatic Life and Its Uses'' to
the ``Water Quality Criteria Documents; Availability'' (45 FR 79341,
November 28, 1980) as amended by the ``Summary of Revisions to
Guidelines for Deriving Numerical National Water Quality Criteria for
the Protection of Aquatic Organisms and Their Uses'' (50 FR 30792, July
29, 1985). (Note: Throughout the remainder of this preamble, this
reference is described as the 1985 Guidelines. Any page number
references are to the actual guidance document, not the notice of
availability in the Federal Register. A copy of the 1985 Guidelines is
available through the National Technical Information Service (PB85-
227049), is in the administrative record for this rule, and is
abstracted in Appendix A of Quality Criteria for Water, 1986.) EPA has
also included in the administrative record of this rule the human
health methodology as described in ``Appendix C--Guidelines and
Methodology Used in the Preparation of Health Effects Assessment
Chapters of the Consent Decree Water Criteria Documents'' (45 FR 79347,
November 28, 1980). (Note: Throughout the remainder of this preamble,
this reference is described as the Human Health Guidelines or the 1980
Guidelines.) EPA also recommends that the following be reviewed:
``Appendix D--Response to Comments on Guidelines for Deriving Water
Quality Criteria for the Protection of Aquatic Life and Its Uses,'' (45
FR 79357, November 28, 1980); ``Appendix E--Responses to Public
Comments on the Human Health Effects Methodology for Deriving Ambient
Water Quality Criteria'' (45 FR 79368, November 28, 1980); and
``Appendix B--Response to Comments on Guidelines for Deriving Numerical
National Water Quality Criteria for the Protection of Aquatic Organisms
and Their Uses'' (50 FR 30793, July 29, 1985). EPA placed into the
administrative record for this rulemaking the most current individual
criteria guidance for the priority toxic pollutants included in today's
rule. (Note: All references to appendices are to the associated Federal
Register publication.)
EPA received many comments related to the issue of what criteria
should apply in the CTR if the CWA section 304(a) criteria guidance is
undergoing re-evaluation, or if new data are developed that may affect
a recommended criterion. As science is always evolving, EPA is faced
with the challenge of promulgating criteria that reflect the best
science and sound science. EPA addressed this challenge in some detail
in its Federal Register notice that contained the Agency's current
section 304(a) criteria guidance (63 FR 68335, December 10, 1998).
There, EPA articulated its policy, reiterated here, that the existing
criteria guidance represent the Agency's best assessment until such
time as EPA's re-evaluation of a criteria guidance value for a
particular chemical is complete. The reason for this is that both EPA's
human health criteria guidance and aquatic life criteria guidance are
developed taking into account numerous variables. For example, for
human health criteria guidance, EPA evaluates many diverse toxicity
studies, whose results feed into a reference dose or cancer potency
estimate that, along with a number of exposure factors and
determination of risk level, results in a guidance criterion. For
aquatic life, EPA evaluates many diverse aquatic toxicity studies to
determine chronic and acute toxicity taking into account how other
factors (such as pH, temperature or hardness) affect toxicity. EPA
also, to the extent possible, addresses bioaccumulation or
bioconcentration. EPA then uses this toxicity information along with
exposure information to determine the guidance criterion. Importantly,
EPA subjects such evaluation to peer review and/or public comment.
For these reasons, EPA generally does not make a change to the
304(a) criteria guidance based on a partial picture of the evolving
science. This makes sense, because to address one piece of new data
without looking at all relevant data is less efficient and results in
regulatory impacts that may go back and forth, when in the end, the
criteria guidance value does not change that much. Certain new changes,
however, do warrant change in criteria guidance, such as a change in a
value in EPA's Integrated Risk Information System (IRIS) because it
represents the Agency consensus about human health impacts. These
changes are sufficiently examined across the Agency such that EPA
believes they can be incorporated into EPA's water quality criteria
guidance. EPA has followed this approach in the CTR. Included in the
administrative record for today's rule is a document entitled ``Status
of Clean Water Act Section 304(a) Criteria'' which further explains
EPA's policy on managing change to criteria guidance.
2. Aquatic Life Criteria
Aquatic life criteria may be expressed in numeric or narrative
form. EPA's 1985 Guidelines describe an objective, internally
consistent and appropriate way of deriving chemical-specific, numeric
water quality criteria for the protection of the presence of, as well
as
[[Page 31689]]
the uses of, both fresh and salt water aquatic organisms.
An aquatic life criterion derived using EPA's CWA section 304(a)
method ``might be thought of as an estimate of the highest
concentration of a substance in water which does not present a
significant risk to the aquatic organisms in the water and their
uses.'' (45 FR 79341.) EPA's guidelines are designed to derive criteria
that protect aquatic communities. EPA's 1985 Guidelines attempt to
provide a reasonable and adequate amount of protection with only a
small possibility of substantial overprotection or underprotection. As
discussed in detail below, there are several individual factors which
may make the criteria somewhat overprotective or underprotective. The
approach EPA is using is believed to be as well balanced as possible,
given the state of the science.
Numerical aquatic life criteria derived using EPA's 1985 Guidelines
are expressed as short-term and long-term averages, rather than one
number, in order that the criterion more accurately reflect
toxicological and practical realities. The combination of a criterion
maximum concentration (CMC), a short-term concentration limit, and a
criterion continuous concentration (CCC), a four-day average
concentration limit, are designed to provide protection of aquatic life
and its uses from acute and chronic toxicity to animals and plants,
without being as restrictive as a one-number criterion would have to be
(1985 Guidelines, pages 4 & 5). The terms CMC and CCC are the formal
names for the two (acute and chronic) values of a criterion for a
pollutant; however, this document will also use the informal synonyms
acute criterion and chronic criterion.
The two-number criteria are intended to identify average pollutant
concentrations which will produce water quality generally suited to
maintenance of aquatic life and designated uses while restricting the
duration of excursions over the average so that total exposures will
not cause unacceptable adverse effects. Merely specifying an average
value over a time period may be insufficient unless the time period is
short, because excursions higher than the average may kill or cause
substantial damage in short periods.
A minimum data set of eight specified families is recommended for
criteria development (details are given in the 1985 Guidelines, page
22). The eight specific families are intended to be representative of a
wide spectrum of aquatic life. For this reason it is not necessary that
the specific organisms tested be actually present in the water body.
EPA's application of its guidelines to develop the criteria matrix in
this rule is judged by the Agency to be appropriate for all waters of
the United States (U.S.), and to all ecosystems (1985 Guidelines, page
4) including those waters of the U.S. and ecosystems in the State of
California.
Fresh water and salt water (including both estuarine and marine
waters) have different chemical compositions, and freshwater and
saltwater species often do not inhabit the same water. To provide
additional accuracy, criteria are developed for fresh water and for
salt water.
For this rule, EPA updated freshwater aquatic life criteria
contained in CWA section 304(a) criteria guidance first published in
the early 1980's and later modified in the NTR, as amended, for the
following ten pollutants: arsenic, cadmium, chromium (VI), copper,
dieldrin, endrin, lindane (gamma BHC), nickel, pentachlorophenol, and
zinc. The updates used as the basis for this rule are explained in a
technical support document entitled, 1995 Updates: Water Quality
Criteria Documents for the Protection of Aquatic Life in Ambient Water
(U.S. EPA-820-B-96-001, September 1996), available in the
administrative record to this rulemaking; this document presents the
derivation of each of the final CMCs and CCCs and the toxicity studies
from which the updated freshwater criteria for the ten pollutants were
derived.
The polychlorinated biphenyls (PCB) criteria in the criteria matrix
for this rule differs from that in the NTR, as amended; for this rule,
the criteria are expressed as the sum of seven aroclors, while for the
NTR, as amended, the criteria are expressed for each of seven aroclors.
The aquatic life criteria for PCBs in the CTR are based on the criteria
contained in the 1980 criteria guidance document for PCBs which is
included in the administrative record for this rule. This criteria
document explains the derivation of aquatic life criteria based on
total PCBs. For more information see the Response to Comments document
for this rule. Today's chronic aquatic life criteria for PCBs are based
on a final residue value (FRV). In EPA's guidelines for deriving
aquatic life criteria, an FRV-based criterion is intended to prevent
concentrations of pollutants in commercially or recreationally
important aquatic species from affecting the marketability of those
species or affecting the wildlife that consume aquatic life.
The proposed CTR included an updated freshwater and saltwater
aquatic life criteria for mercury. In today's final rule, EPA has
reserved the mercury criteria for freshwater and saltwater aquatic
life, but is promulgating human health criteria for mercury for all
surface waters in California. In some instances, the human health
mercury criteria included in today's final rule may not protect some
aquatic species or threatened or endangered species. In such instances,
more stringent mercury limits may be determined and implemented through
use of the State's narrative criterion. The reasons for reserving the
mercury aquatic life numbers are explained in further detail in Section
L, Endangered Species Act.
a. Freshwater Acute Selenium Criterion
EPA proposed a different freshwater acute aquatic life criterion
for selenium for this rule than was promulgated in the NTR, as amended.
EPA's proposed action was consistent with EPA's proposed selenium
criterion maximum concentration for the Water Quality Guidance for the
Great Lakes System (61 FR 58444, November 14, 1996). This proposal took
into account data showing that selenium's two most prevalent oxidation
states, selenite and selenate, present differing potentials for aquatic
toxicity, as well as new data which indicated that various forms of
selenium are additive. Additivity increases the toxicity of mixtures of
different forms of the pollutant. The proposed approach produces a
different selenium acute criterion concentration, or CMC, depending
upon the relative proportions of selenite, selenate, and other forms of
selenium that are present.
The preamble to the August 5, 1997, proposed rule provided a
lengthy discussion of this proposed criterion for the State of
California. See 62 FR 42160-42208. EPA incorporates that discussion
here as part of this rulemaking record. In 1996, a similar discussion
was included in the proposed rule for the Great Lakes System.
Commenters questioned several aspects of the Great Lakes proposal. EPA
is continuing to respond to those comments, and to follow up with
additional literature review and toxicity testing. In addition, the
U.S. FWS and U.S. NMFS (collectively, the Services) are concerned that
EPA's proposed criterion may not be sufficiently protective of certain
threatened and endangered species in California. Because the Services
believe there is a lack of data to show for certain that the proposed
criterion would not affect threatened and endangered species, the
Services prefer that EPA further investigate the protectiveness of the
[[Page 31690]]
criterion before finalizing the proposed criterion. Therefore, EPA is
not promulgating a final acute freshwater selenium criterion at this
time.
b. Dissolved Metals Criteria
In December of 1992, in the NTR, EPA promulgated water quality
criteria for several States that had failed to meet the requirements of
CWA section 303(c)(2)(B). Included among the water quality criteria
promulgated were numeric criteria for the protection of aquatic life
for 11 metals: arsenic, cadmium, chromium (III), chromium (VI), copper,
lead, mercury, nickel, selenium, silver and zinc. Criteria for two
metals applied to the State of California: chromium III and selenium.
The Agency received extensive public comment during the development
of the NTR regarding the most appropriate approach for expressing the
aquatic life metals criteria. The principal issue was the correlation
between metals that are measured and metals that are bioavailable and
toxic to aquatic life. It is now the Agency's policy that the use of
dissolved metal to set and measure compliance with aquatic life water
quality standards is the recommended approach, because dissolved metal
more closely approximates the bioavailable fraction of the metal in the
water column than does total recoverable metal.
Since EPA's previous aquatic life criteria guidance had been
expressed as total recoverable metal, to express the criteria as
dissolved, conversion factors were developed to account for the
possible presence of particulate metal in the laboratory toxicity tests
used to develop the total recoverable criteria. EPA included a set of
recommended freshwater conversion factors with its Metals Policy (see
Office of Water Policy and Technical Guidance on Interpretation and
Implementation of Aquatic Life Metals Criteria, Martha G. Prothro,
Acting Assistant Administrator for Water, October 1, 1993). Based on
additional laboratory evaluations that simulated the original toxicity
tests, EPA refined the procedures used to develop freshwater conversion
factors for aquatic life criteria. These new conversion factors were
made available for public review and comment in the amendments to the
NTR on May 4, 1995, at 60 FR 22229. They are also contained in today's
rule at 40 CFR 131.38(b)(2).
The preamble to the August 5, 1997, proposed rule provided a more
detailed discussion of EPA's metals policy concerning the aquatic life
water quality criteria for the State of California. See 62 FR 42160-
42208. EPA incorporates that discussion here as part of this rulemaking
record. Many commenters strongly supported the Agency's policy on
dissolved metals aquatic life criteria. A few commenters expressed an
opinion that the metals policy may not provide criteria that are
adequately protective of aquatic or other species. Responses to those
comments are contained in a memo to the CTR record entitled
``Discussion of the Use of Dissolved Metals in the CTR'' (February 1,
2000, Jeanette Wiltse) and EPA's response to comments document which
are both contained in the administrative record for the final rule.
Calculation of Aquatic Life Dissolved Metals Criteria: Metals
criteria values for aquatic life in today's rule in the matrix at
131.38(b)(1) are shown as dissolved metal. These criteria have been
calculated in one of two ways. For freshwater metals criteria that are
hardness-dependent, the metals criteria value is calculated separately
for each hardness using the table at 40 CFR 131.38(b)(2). (The
hardness-dependent freshwater values presented in the matrix at 40 CFR
131.38(b)(1) have been calculated using a hardness of 100 mg/l as CaCO3
for illustrative purposes only.) The hardness-dependent criteria are
then multiplied by the appropriate conversion factors in the table at
40 CFR 131.38(b)(2). Saltwater and freshwater metals criteria that are
not hardness-dependent are calculated by taking the total recoverable
criteria values (from EPA's national section 304(a) criteria guidance,
as updated and described in section F.2.a.) before rounding, and
multiplying them by the appropriate conversion factors. The final
dissolved metals criteria values, as they appear in the matrix at 40
CFR 131.38(b)(1), are rounded to two significant figures.
Translators for Dissolved to Total Recoverable Metals Limits: EPA's
National Pollutant Discharge Elimination System (NPDES) regulations
require that limits for metals in permits be stated as total
recoverable in most cases (see 40 CFR 122.45(c)) except when an
effluent guideline specifies the limitation in another form of the
metal, the approved analytical methods measure only dissolved metal, or
the permit writer expresses a metal's limit in another form (e.g.,
dissolved, specific valence, or total) when required to carry out
provisions of the CWA. This is because the chemical conditions in
ambient waters frequently differ substantially from those in the
effluent and these differences result in changes in the partitioning
between dissolved and absorbed forms of the metal. This means that if
effluent limits were expressed in the dissolved form, additional
particulate metal could dissolve in the receiving water causing the
criteria to be exceeded. Expressing criteria as dissolved metal
requires translation between different metal forms in the calculation
of the permit limit so that a total recoverable permit limit can be
established that will achieve water quality standards. Thus, it is
important that permitting authorities and other authorities have the
ability to translate between dissolved metal in ambient waters and
total recoverable metal in effluent.
EPA has completed guidance on the use of translators to convert
from dissolved metals criteria to total recoverable permit limits. The
document, The Metals Translator: Guidance for Calculating a Total
Recoverable Permit Limit From a Dissolved Criterion (EPA 823-B-96-007,
June 1996), is included in the administrative record for today's rule.
This technical guidance examines how to develop a metals translator
which is defined as the fraction of total recoverable metal in the
downstream water that is dissolved, i.e., the dissolved metal
concentration divided by the total recoverable metal concentration. A
translator may take one of three forms: (1) It may be assumed to be
equivalent to the criteria guidance conversion factors; (2) it may be
developed directly as the ratio of dissolved to total recoverable
metal; and (3) it may be developed through the use of a partition
coefficient that is functionally related to the number of metal binding
sites on the adsorbent in the water column (e.g., concentrations of
total suspended solids or TSS). This guidance document discusses these
three forms of translators, as well as field study designs, data
generation and analysis, and site-specific study plans to generate
site-specific translators.
California Regional Water Quality Control Boards may use any of
these methods in developing water quality-based permit limits to meet
water quality standards based on dissolved metals criteria. EPA
encourages the State to adopt a statewide policy on the use of
translators so that the most appropriate method or methods are used
consistently within California.
c. Application of Metals Criteria
In selecting an approach for implementing the metals criteria, the
principal issue is the correlation between metals that are measured and
metals that are biologically available and toxic. In order to assure
that the metals criteria are appropriate for the chemical conditions
under which they are applied, EPA is providing for the
[[Page 31691]]
adjustment of the criteria through application of the ``water-effect
ratio'' procedure. EPA notes that performing the testing to use a site-
specific water-effect ratio is optional on the part of the State.
In the NTR, as amended, EPA identified the water-effect ratio (WER)
procedure as a method for optional site-specific criteria development
for certain metals. The WER approach compares bioavailability and
toxicity of a specific pollutant in receiving waters and in laboratory
waters. A WER is an appropriate measure of the toxicity of a material
obtained in a site water divided by the same measure of the toxicity of
the same material obtained simultaneously in a laboratory dilution
water.
On February 22, 1994, EPA issued Interim Guidance on the
Determination and Use of the Water-Effect Ratios for Metals (EPA 823-B-
94-001) now incorporated into the updated Second Edition of the Water
Quality Standards Handbook, Appendix L. A copy of the Handbook is
contained in the administrative record for today's rule. In accordance
with the WER guidance and where application of the WER is deemed
appropriate, EPA strongly encourages the application of the WER on a
watershed or water body basis as part of a water quality criteria in
California as opposed to the application on a discharger-by-discharger
basis through individual NPDES permits. This approach is technically
sound and an efficient use of resources. However, discharger specific
WERs for individual NPDES permit limits are possible and potentially
efficient where the NPDES discharger is the only point source
discharger to a specific water body.
The rule requires a default WER value of 1.0 which will be assumed,
if no site-specific WER is determined. To use a WER other than the
default of 1.0, the rule requires that the WER must be determined as
set forth in EPA's WER guidance or by another scientifically defensible
method that has been adopted by the State as part of its water quality
standards program and approved by EPA.
The WER is a more comprehensive mechanism for addressing
bioavailability issues than simply expressing the criteria in terms of
dissolved metal. Consequently, expressing the criteria in terms of
dissolved metal, as done in today's rule for California, does not
completely eliminate the utility of the WER. This is particularly true
for copper, a metal that forms reduced-toxicity complexes with
dissolved organic matter.
The Interim Guidance on Determination and Use of Water-Effect
Ratios for Metals explains the relationship between WERs for dissolved
criteria and WERs for total recoverable criteria. Dissolved
measurements are to be used in the site-specific toxicity testing
underlying the WERs for dissolved criteria. Because WERs for dissolved
criteria generally are little affected by elevated particulate
concentrations, EPA expects those WERs to be somewhat less than WERs
for total recoverable criteria in such situations. Nevertheless, after
the site-specific ratio of dissolved to total metal has been taken into
account, EPA expects a permit limit derived using a WER for a dissolved
criterion to be similar to the permit limit that would be derived from
the WER for the corresponding total recoverable criterion.
d. Saltwater Copper Criteria
The saltwater copper criteria for aquatic life in today's rule are
4.8 µg/l (CMC) and 3.1 µg/l (CCC) in the dissolved
form. These criteria reflect new data including data collected from
studies for the New York/New Jersey Harbor and the San Francisco Bay
indicating a need to revise the former copper 304(a) criteria guidance
document to reflect a change in the saltwater CMC and CCC aquatic life
values. These data also reflect a comprehensive literature search
resulting in added toxicity test data for seven new species to the
database for the saltwater copper criteria. EPA believes these new data
have national implications and the national criteria guidance now
contains a CMC of 4.8 µg/l dissolved and a CCC of 3.1
µg/l dissolved. In the amendments to the NTR, EPA noticed the
availability of data to support these changes to the NTR, and solicited
comments. The data can be found in the draft document entitled, Ambient
Water Quality Criteria--Copper, Addendum 1995. This document is
available from the Office of Water Resource Center and is available for
review in the administrative record for today's rule.
e. Chronic Averaging Period
In establishing water quality criteria, EPA generally recommends an
``averaging period'' which reflects the duration of exposure required
to elicit effects in individual organisms (TSD, Appendix D-2). The
criteria continuous concentration, or CCC, is intended to be the
highest concentration that could be maintained indefinitely in a water
body without causing an unacceptable effect on the aquatic community or
its uses (TSD, Appendix D-1). As aquatic organisms do not generally
experience steady exposure, but rather fluctuating exposures to
pollutants, and because aquatic organisms can generally tolerate higher
concentrations of pollutants over a shorter periods of time, EPA
expects that the concentration of a pollutant can exceed the CCC
without causing an unacceptable effect if (a) the magnitude and
duration of exceedences are appropriately limited and (b) there are
compensating periods of time during which the concentration is below
the CCC. This is done by specifying a duration of an ``averaging
period'' over which the average concentration should not exceed the CCC
more often than specified by the frequency (TSD, Appendix D-1).
EPA is promulgating a 4-day averaging period for chronic criteria,
which means that measured or predicted ambient pollutant concentrations
should be averaged over a 4-day period to determine attainment of
chronic criteria. The State may apply to EPA for approval of an
alternative averaging period. To do so, the State must submit to EPA
the basis for such alternative averaging period.
The most important consideration for setting an appropriate
averaging period is the length of time that sensitive organisms can
tolerate exposure to a pollutant at levels exceeding a criterion
without showing adverse effects on survival, growth, or reproduction.
EPA believes that the chronic averaging period must be shorter than the
duration of the chronic tests on which the CCC is based, since, in some
cases, effects are elicited before exposure of the entire duration.
Most of the toxicity tests used to establish the chronic criteria are
conducted using steady exposure to toxicants for a least 28 days (TSD,
page 35). Some chronic tests, however, are much shorter than this (TSD,
Appendix D-2). EPA selected the 4-day averaging period based on the
shortest duration in which chronic test effects are sometimes observed
for certain species and toxicants. In addition, EPA believes that the
results of some chronic tests are due to an acute effect on a sensitive
life stage that occurs some time during the test, rather than being
caused by long-term stress or long-term accumulation of the test
material in the organisms.
Additional discussion of the rationale for the 4-day averaging
period is contained in Appendix D of the TSD. Balancing all of the
above factors and data, EPA believes that the 4-day averaging period
falls within the scientifically reasonable range of values for choice
of the averaging period, and is an appropriate length of time of
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pollutant exposure to ensure protection of sensitive organisms.
EPA established a 4-day averaging period in the NTR. In settlement
of litigation on the NTR, EPA stated that it was ``in the midst of
conducting, sponsoring, or planning research related to the basis for
and application of'' water quality criteria and mentioned the issue of
averaging period. See Partial Settlement Agreement in American Forest
and Paper Ass'n, Inc. et al. v. U.S. EPA (Consolidated Case No. 93-0694
(RMU), D.D.C.). EPA is re-evaluating issues raised about averaging
periods and will, if appropriate, revise the 1985 Guidelines.
EPA received public comment relevant to the averaging period during
the comment period for the 1995 Amendments to the NTR (60 FR 22228, May
4, 1995), although these public comments did not address the chronic
averaging period separately from the allowable excursion frequency and
the design flow. Comments recommended that EPA use the 30Q5 design flow
for chronic criteria.
While EPA is undertaking analysis of the chronic design conditions
as part of the revisions to the 1985 Guidelines, EPA has not yet
completed this work. Until this work is complete, for the reasons set
forth in the TSD, EPA continues to believe that the 4-day chronic
averaging period represents a reasonable, defensible value for this
parameter.
EPA added language to the final rule which will enable the State to
adopt alternative averaging periods and frequencies and associated
design flows where appropriate. The State may apply to EPA for approval
of alternative averaging periods and frequencies and related design
flows; the State must submit the bases for any changes. Before
approving any change, EPA will publish for public comment, a notice
proposing the changes.
f. Hardness
Freshwater aquatic life criteria for certain metals are expressed
as a function of hardness because hardness and/or water quality
characteristics that are usually correlated with hardness can reduce or
increase the toxicities of some metals. Hardness is used as a surrogate
for a number of water quality characteristics which affect the toxicity
of metals in a variety of ways. Increasing hardness has the effect of
decreasing the toxicity of metals. Water quality criteria to protect
aquatic life may be calculated at different concentrations of
hardnesses measured in milligrams per liter (mg/l) as calcium carbonate
(CaCO3).
Section 131.38(b)(2) of the final rule presents the hardness-
dependent equations for freshwater metals criteria. For example, using
the equation for zinc, the total recoverable CMCs at a hardness of 10,
50, 100 or 200 mg/l as CaCO3 are 17, 67, 120 and 220
micrograms per liter (µg/l), respectively. Thus, the specific
value in the table in the regulatory text is for illustrative purposes
only. Most of the data used to develop these hardness equations for
deriving aquatic life criteria for metals were in the range of 25 mg/l
to 400 mg/l as CaCO3, and the formulas are therefore most
accurate in this range. The majority of surface waters nationwide and
in California have a hardness of less than 400 mg/l as
CaCO3.
In the past, EPA generally recommended that 25 mg/l as
CaCO3 be used as a default hardness value in deriving
freshwater aquatic life criteria for metals when the ambient (or
actual) hardness value is below 25 mg/l as CaCO3. However,
use of the approach results in criteria that may not be fully
protective. Therefore, for waters with a hardness of less than 25 mg/l
as CaCO3, criteria should be calculated using the actual
ambient hardness of the surface water.
In the past, EPA generally recommended that if the hardness was
over 400 mg/l, two options were available: (1) Calculate the criterion
using a default WER of 1.0 and using a hardness of 400 mg/l in the
hardness equation; or (2) calculate the criterion using a WER and the
actual ambient hardness of the surface water in the equation. Use of
the second option is expected to result in the level of protection
intended in the 1985 Guidelines whereas use of the first option is
thought to result in an even more protective aquatic life criterion. At
high hardness there is an indication that hardness and related
inorganic water quality characteristics do not have as much of an
effect on toxicity of metals as they do at lower hardnesses. Related
water quality characteristics do not correlate as well at higher
hardnesses as they do at lower hardnesses. Therefore, if hardness is
over 400 mg/l as CaCO3, a hardness of 400 mg/l as
CaCO3 should be used with a default WER of 1.0;
alternatively, the WER and actual hardness of the surface water may be
used.
EPA requested comments in the NTR amendments on the use of actual
ambient hardness for calculating criteria when the hardness is below 25
mg/l as CaCO3, and when hardness is greater than 400 mg/l as
CaCO3. Most of the comments received were in favor of using
the actual hardness with the use of the water-effect ratio (1.0 unless
otherwise specified by the permitting authority) when the hardness is
greater than 400 mg/l as CaCO3. A few commenters did not
want the water-effect ratio to be mandatory in calculating hardness,
and other commenters had concerns about being responsible for deriving
an appropriate water-effect ratio. Overall, the commenters were in
favor of using the actual hardness when calculating hardness-dependent
freshwater metals criteria for hardness between 0-400 mg/l as
CaCO3. EPA took those comments into account in promulgating
today's rule.
A hardness equation is most accurate when the relationships between
hardness and the other important inorganic constituents, notably
alkalinity and pH, are nearly identical in all of the dilution waters
used in the toxicity tests and in the surface waters to which the
equation is to be applied. If an effluent raises hardness but not
alkalinity and/or pH, using the hardness of the downstream water might
provide a lower level of protection than intended by the 1985
guidelines. If it appears that an effluent causes hardness to be
inconsistent with alkalinity and/or pH, the intended level of
protection will usually be maintained or exceeded if either (1) data
are available to demonstrate that alkalinity and/or pH do not affect
the toxicity of the metal, or (2) the hardness used in the hardness
equation is the hardness of upstream water that does not contain the
effluent. The level of protection intended by the 1985 guidelines can
also be provided by using the WER procedure.
In some cases, capping hardness at 400 mg/l might result in a level
of protection that is higher than that intended by the 1985 guidelines,
but any such increase in the level of protection can be overcome by use
of the WER procedure. For metals whose criteria are expressed as
hardness equations, use of the WER procedure will generally be intended
to account for effects of such water quality characteristics as total
organic carbon on the toxicities of metals. The WER procedure is
equally useful for accounting for any deviation from a hardness
equation in a site water.
3. Human Health Criteria
EPA's CWA section 304(a) human health criteria guidance provides
criteria recommendations to minimize adverse human effects due to
substances in ambient water. EPA's CWA section 304(a) criteria guidance
for human health are based on two types of
[[Page 31693]]
toxicological endpoints: (1) carcinogenicity and (2) systemic toxicity
(i.e., all other adverse effects other than cancer). Thus, there are
two procedures for assessing these health effects: one for carcinogens
and one for non-carcinogens.
If there are no data on how a chemical agent causes cancer, EPA's
existing human health guidelines assume that carcinogenicity is a
``non-threshold phenomenon,'' that is, there are no ``safe'' or ``no-
effect levels'' because even extremely small doses are assumed to cause
a finite increase in the incidence of the effect (i.e., cancer).
Therefore, EPA's water quality criteria guidance for carcinogens are
presented as pollutant concentrations corresponding to increases in the
risk of developing cancer. See Human Health Guidelines at 45 FR 79347.
With existing criteria, pollutants that do not manifest any
apparent carcinogenic effect in animal studies (i.e., systemic
toxicants), EPA assumes that the pollutant has a threshold below which
no effect will be observed. This assumption is based on the premise
that a physiological mechanism exists within living organisms to avoid
or overcome the adverse effect of the pollutant below the threshold
concentration.
Note: Recent changes in the Agency's cancer guidelines
addressing these assumptions are described in the Draft Water
Quality Criteria Methodology: Human Health, 63 FR 43756, August 14,
1998.
The human health risks of a substance cannot be determined with any
degree of confidence unless dose-response relationships are quantified.
Therefore, a dose-response assessment is required before a criterion
can be calculated. The dose-response assessment determines the
quantitative relationships between the amount of exposure to a
substance and the onset of toxic injury or disease. Data for
determining dose-response relationships are typically derived from
animal studies, or less frequently, from epidemiological studies in
exposed populations.
The dose-response information needed for carcinogens is an estimate
of the carcinogenic potency of the compound. Carcinogenic potency is
defined here as a general term for a chemical's human cancer-causing
potential. This term is often used loosely to refer to the more
specific carcinogenic or cancer slope factor which is defined as an
estimate of carcinogenic potency derived from animal studies or
epidemiological data of human exposure. It is based on extrapolation
from test exposures of high doses over relatively short periods of time
to more realistic low doses over a lifetime exposure period by use of
linear extrapolation models. The cancer slope factor, q1*, is EPA's
estimate of carcinogenic potency and is intended to be a conservative
upper bound estimate (e.g. 95% upper bound confidence limit).
For non-carcinogens, EPA uses the reference dose (RfD) as the dose-
response parameter in calculating the criteria. For non-carcinogens,
oral RfD assessments (hereinafter simply ``RfDs'') are developed based
on pollutant concentrations that cause threshold effects. The RfD is an
estimate (with uncertainty spanning perhaps an order of magnitude) of a
daily exposure to the human population (including sensitive subgroups)
that is likely to be without appreciable risk of deleterious effects
during a lifetime. See Human Health Guidelines. The RfD was formerly
referred to as an ``Acceptable Daily Intake'' or ADI. The RfD is useful
as a reference point for gauging the potential effect of other doses.
Doses that are less than the RfD are not likely to be associated with
any health risks, and are therefore less likely to be of regulatory
concern. As the frequency of exposures exceeding the RfD increases and
as the size of the excess increases, the probability increases that
adverse effect may be observed in a human population. Nonetheless, a
clear conclusion cannot be categorically drawn that all doses below the
RfD are ``acceptable'' and that all doses in excess of the RfD are
``unacceptable.'' In extrapolating non-carcinogen animal test data to
humans to derive an RfD, EPA divides either a No Observed-Adverse
Effect Level (NOAEL), Lowest Observed Adverse Effect Level (LOAEL), or
other benchmark dose observed in animal studies by an ``uncertainty
factor'' which is based on professional judgment of toxicologists and
typically ranges from 10 to 10,000.
For CWA section 304(a) human health criteria development, EPA
typically considers only exposures to a pollutant that occur through
the ingestion of water and contaminated fish and shellfish. Thus, the
criteria are based on an assessment of risks related to the surface
water exposure route only where designated uses are drinking water and
fish and shellfish consumption.
The assumed exposure pathways in calculating the criteria are the
consumption of 2 liters per day of water at the criteria concentration
and the consumption of 6.5 grams per day of fish and shellfish
contaminated at a level equal to the criteria concentration but
multiplied by a ``bioconcentration factor.'' The use of fish and
shellfish consumption as an exposure factor requires the quantification
of pollutant residues in the edible portions of the ingested species.
Bioconcentration factors (BCFs) are used to relate pollutant
residues in aquatic organisms to the pollutant concentration in ambient
waters. BCFs are quantified by various procedures depending on the
lipid solubility of the pollutant. For lipid soluble pollutants, the
average BCF is calculated from the weighted average percent lipids in
the edible portions of fish and shellfish, which is about 3%; or it is
calculated from theoretical considerations using the octanol/water
partition coefficient. For non-lipid soluble compounds, the BCF is
determined empirically. The assumed water consumption is taken from the
National Academy of Sciences publication Drinking Water and Health
(1977). (Referenced in the Human Health Guidelines.) This value is
appropriate as it includes a margin of safety so that the general
population is protected. See also EPA's discussion of the 2.0 liters/
day assumption at 61 FR 65183 (Dec. 11, 1996). The 6.5 grams per day
contaminated fish and shellfish consumption value was equivalent to the
average per-capita consumption rate of all (contaminated and non-
contaminated) freshwater and estuarine fish and shellfish for the U.S.
population. See Human Health Guidelines.
EPA assumes in calculating water quality criteria that the exposed
individual is an average adult with body weight of 70 kilograms. EPA
assumes 6.5 grams per day of contaminated fish and shellfish
consumption and 2.0 liters per day of contaminated drinking water
consumption for a 70 kilogram person in calculating the criteria.
Regarding issues concerning criteria development and differences in
dose per kilogram of body weight, RfDs are always derived based on the
most sensitive health effect endpoint. Therefore, when that basis is
due to a chronic or lifetime health effect, the exposure parameters
assume the exposed individual to be the average adult, as indicated
above.
In the absence of this final rule, there may be particular risks to
children. EPA believes that children are protected by the human health
criteria contained in this final rule. Children are protected against
other less sensitive adverse health endpoints due to the conservative
way that the RfDs are derived. An RfD is a public health protective
endpoint. It is an amount of a chemical that can be consumed on a daily
basis for a lifetime without expecting an adverse effect. RfDs are
based on sensitive health endpoints and
[[Page 31694]]
are calculated to be protective for sensitive human sub-populations
including children. If the basis of the RfD was due to an acute or
shorter-term developmental effect, EPA uses exposure parameters other
than those indicated above. Specifically, EPA uses parameters most
representative of the population of concern (e.g., the health criteria
for nitrates based on infant exposure parameters). For carcinogens, the
risk assessments are upper bound one in a million (10-6)
lifetime risk numbers. The risk to children is not likely to exceed
these upper bounds estimates and may be zero at low doses. The exposure
assumptions for drinking water and fish protect children because they
are conservative for infants and children. EPA assumes 2 liters of
untreated surface water and 6.5 grams of freshwater and estuarine fish
are consumed each day. EPA believes the adult fish consumption
assumption is conservative for children because children generally
consume marine fish not freshwater and estuarine.
EPA has a process to develop a scientific consensus on oral
reference dose assessments and carcinogenicity assessments (hereinafter
simply cancer slope factors or slope factors or q1*s). Through this
process, EPA develops a consensus of Agency opinion which is then used
throughout EPA in risk management decision-making. EPA maintains an
electronic data base which contains the official Agency consensus for
oral RfD assessments and carcinogenicity assessments which is known as
the Integrated Risk Information System (IRIS). It is available for use
by the public on the National Institutes of Health's National Library
of Medicine's TOXNET system, and through diskettes from the National
Technical Information Service (NTIS). (NTIS access number is PB 90-
591330.)
Section 304(a)(1) of the CWA requires EPA to periodically revise
its criteria guidance to reflect the latest scientific knowledge: ``(A)
On the kind and extent of all identifiable effects on health and
welfare * * *; (B) on the concentration and dispersal of pollutants, or
their byproducts, through biological, physical, and chemical processes;
and (C) on the effects of pollutants on the biological community
diversity, productivity, and stability, including information on the
factors affecting eutrophication rates of organic and inorganic
sedimentation for varying types of receiving waters.'' In developing
up-to-date water quality criteria for the protection of human health,
EPA uses the most recent IRIS values (RfDs and q1*s) as the
toxicological basis in the criterion calculation. IRIS reflects EPA's
most current consensus on the toxicological assessment for a chemical.
In developing the criteria in today's rule, the IRIS values as of
October 1996 were used together with currently accepted exposure
parameters for bioconcentration, fish and shellfish and water
consumption, and body weight. The IRIS cover sheet for each pollutant
criteria included in today's rule is contained in the administrative
record.
For the human health criteria included in today's rule, EPA used
the Human Health Guidelines on which criteria recommendations from the
appropriate CWA section 304(a) criteria guidance document were based.
(These documents are also placed in the administrative record for
today's rule.) Where EPA has changed any parameters in IRIS used in
criteria derivation since issuance of the criteria guidance document,
EPA recalculated the criteria recommendation with the latest IRIS
information. Thus, there are differences between the original 1980
criteria guidance document recommendations, and those in this rule, but
this rule presents EPA's most current CWA section 304(a) criteria
recommendation. The basis (q1* or RfD) and BCF for each pollutant
criterion in today's rule is contained in the rule's Administrative
Record Matrix which is included in the administrative record for the
rule. In addition, all recalculated human health numbers are denoted by
an ``a'' in the criteria matrix in 40 CFR 131.38(b)(1) of the rule. The
pollutants for which a revised human health criterion has been
calculated since the December 1992 NTR include:
mercury
dichlorobromomethane
1,2-dichloropropane
1,2-trans-dichloroethylene
2,4-dimethylphenol
acenaphthene
benzo(a)anthracene
benzo(a)pyrene
benzo(b)flouranthene
benzo(k)flouranthene
2-chloronaphthalene
chrysene
dibenzo(a,h)anthracene
indeno(1,2,3-cd)pyrene
N-nitrosodi-n-propylamine
alpha-endosulfan
beta-endosulfan
endosulfan sulfate
2-chlorophenol
butylbenzyl phthalate
polychlorinated biphenyls.
In November of 1991, the proposed NTR presented criteria for
several pollutants in parentheses. These were pollutants for which, in
1980, insufficient information existed to develop human health water
quality criteria, but for which, in 1991, sufficient information
existed. Since these criteria did not undergo the public review and
comment in a manner similar to the other water quality criteria
presented in the NTR (for which sufficient information was available in
1980 to develop a criterion, as presented in the 1980 criteria guidance
documents), they were not proposed for adoption into the water quality
criteria, but were presented to serve as notice for inclusion in future
State triennial reviews. Today's rule promulgates criteria for these
nine pollutants:
copper
1, 2-dichloropropane
1,2-trans-dichloroethylene
2,4-dimethylphenol
acenaphthene
2-chloronaphthalene
N-nitrosodi-n-propylamine
2-chlorophenol
butylbenzene phthalate
All the criteria are based on IRIS values--either an RfD or q1*--
which were listed on IRIS as of November 1991, the date of the proposed
NTR. These values have not changed since the final NTR was published in
December of 1992. The rule's Administrative Record Matrix in the
administrative record of today's rule contains the specific RfDs, q1*s,
and BCFs used in calculating these criteria.
Proposed Changes to the Human Health Criteria Methodology: EPA
recently proposed revisions to the 1980 ambient water quality criteria
derivation guidelines (the Human Health Guidelines). See Draft Water
Quality Criteria Methodology: Human Health, 63 FR 43756, August 14,
1998; see also Draft Water Quality Criteria Methodology: Human Health,
U.S. EPA Office of Water, EPA 822-Z-98-001. The EPA revisions consist
of five documents: Draft Water Quality Criteria Methodology: Human
Health, EPA 822-Z-98-001; Ambient Water Quality Criteria Derivation
Methodology Human Health, Technical Support Document, Final Draft, EPA-
822-B-98-005; and three Ambient Water Quality Criteria for the
Protection of Human Health, Drafts--one each for Acrylonitrile, 1,3-
Dichloropropene (1,3-DCP), and Hexachlorobutadiene (HCBD),
respectively, EPA-822-R-98-006, -005, and -004. All five documents are
contained in the administrative record for today's rule.
The proposed methodology revisions reflect significant scientific
advances that have occurred during the past nineteen years in such key
areas as cancer and noncancer risk assessments, exposure assessments
and bioaccumulation. For specific details on
[[Page 31695]]
these proposed changes and others, please refer to the Federal Register
notice or the EPA document.
It should be noted that some of the proposed changes may result in
significant numeric changes in the ambient water quality criteria.
However, EPA will continue to rely on existing criteria as the basis
for regulatory and non-regulatory decisions, until EPA revises and
reissues a 304(a) criteria guidance using the revised final human
health criteria methodology. The existing criteria are still viewed as
scientifically acceptable by EPA. The intention of the proposed
methodology revisions is to present the latest scientific advancements
in the areas of risk and exposure assessment in order to incrementally
improve the already sound toxicological and exposure bases for these
criteria. As EPA's current human health criteria are the product of
many years worth of development and peer review, it is reasonable to
assume that revisiting all existing criteria, and incorporating peer
review into such review, could require comparable amounts of time and
resources. Given these circumstances, EPA proposed a process for
revisiting these criteria as part of the overall revisions to the
methodology for deriving human health criteria. This process is
discussed in the Implementation Section of the Notice of Draft
Revisions to the Methodology for Deriving Ambient Water Quality
Criteria for the Protection of Human Health (see 63 FR 43771-43776,
August 14, 1998).
The State of California in its Ocean Plan, adopted in 1990 and
approved by EPA in 1991, established numeric water quality criteria
using an average fish and shellfish consumption rate of 23 grams per
day. This value is based on an earlier California Department of Health
Services estimate. The State is currently in the process of readopting
its water quality control plans for inland surface waters, enclosed
bays, and estuaries. The State intends to consider information on fish
and shellfish consumption rates evaluated and summarized in a report
prepared by the State's Pesticide and Environmental Toxicology Section
of the Office of Environmental Health Hazard Assessment of the
California Environmental Protection Agency. The report, entitled,
Chemicals in Fish Report No. 1: Consumption of Fish and Shellfish in
California and the United States, was published in final draft form in
July of 1997, and released to the public on September 16, 1997. The
report is currently undergoing final evaluation, and is expected to
published in final form in the near future. This final draft report is
contained in the administrative record for today's rule. Although EPA
has not used this fish consumption value here because this information
has not yet been finalized, the State may use any appropriate higher
state-specific fish and shellfish consumption rates in its readoption
of criteria in its statewide plans.
a. 2,3,7,8-TCDD (Dioxin) Criteria
In today's action, EPA is promulgating human health water quality
criteria for 2,3,7,8-tetrachlorodibenzo-p-dioxin (``dioxin'') at the
same levels as promulgated in the NTR, as amended. These criteria are
derived from EPA's 1984 CWA section 304(a) criteria guidance document
for dioxin.
For National Pollutant Discharge Elimination System (NPDES)
purposes, EPA supports the regulation of other dioxin and dioxin-like
compounds through the use of toxicity equivalencies or TEQs in NPDES
permits (see discussion below). For California waters, if the discharge
of dioxin or dioxin-like compounds has reasonable potential to cause or
contribute to a violation of a narrative criterion, numeric water
quality-based effluent limits for dioxin or dioxin-like compounds
should be included in NPDES permits and should be expressed using a TEQ
scheme.
EPA has been evaluating the health threat posed by dioxin nearly
continuously for over two decades. Following issuance of the 1984
criteria guidance document, evaluating the health effects of dioxin and
recommending human health criteria for dioxin, EPA prepared draft
reassessments reviewing new scientific information relating to dioxin
in 1985 and 1988. EPA's Science Advisory Board (SAB), reviewing the
1988 draft reassessment, concluded that while the risk assessment
approach used in 1984 criteria guidance document had inadequacies, a
better alternative was unavailable (see SAB's Dioxin Panel Review of
Documents from the Office or Research and Development relating to the
Risk and Exposure Assessment of 2,3,7,8-TCDD (EPA-SAB-EC-90-003,
November 28, 1989) included in the administrative record for today's
rule). Between 1988 and 1990, EPA issued numerous reports and guidances
relating to the control of dioxin discharges from pulp and paper mills.
See e.g., EPA Memorandum, ``Strategy for the Regulation of Discharges
of PHDDs & PHDFs from Pulp and Paper Mills to the Waters of the United
States,'' from Assistant Administrator for Water to Regional Water
Management Division Directors and NPDES State Directors, dated May 21,
1990 (AR NL-16); EPA Memorandum, ``State Policies, Water Quality
Standards, and Permit Limitations Related to 2,3,7,8-TCDD in Surface
Water,'' from the Assistant Administrator for Water to Regional Water
Management Division Directors, dated January 5, 1990 (AR VA-66). These
documents are available in the administrative record for today's rule.
In 1991, EPA's Administrator announced another scientific
reassessment of the risks of exposure to dioxin (see Memorandum from
Administrator William K. Reilly to Erich W. Bretthauer, Assistant
Administrator for Research and Development and E. Donald Elliott,
General Counsel, entitled Dioxin: Follow-Up to Briefing on Scientific
Developments, April 8, 1991, included in the administrative record for
today's rule). At that time, the Administrator made clear that while
the reassessment was underway, EPA would continue to regulate dioxin in
accordance with existing Agency policy. Thereafter, the Agency
proceeded to regulate dioxin in a number of environmental programs,
including standards under the Safe Drinking Water Act and the CWA.
The Administrator's promulgation of the dioxin human health
criteria in the 1992 NTR affirmed the Agency's decision that the
ongoing reassessment should not defer or delay regulating this potent
contaminant, and further, that the risk assessment in the 1984 criteria
guidance document for dioxin continued to be scientifically defensible.
Until the reassessment process was completed, the Agency could not
``say with any certainty what the degree or directions of any changes
in the risk estimates might be'' (57 FR 60863-64).
The basis for the dioxin criteria as well as the decision to
include the dioxin criteria in the 1992 NTR pending the results of the
reassessment were challenged. See American Forest and Paper Ass'n, Inc.
et al. v. U.S. EPA (Consolidated Case No. 93-0694 (RMU) D.D.C.). By
order dated September 4, 1996, the Court upheld EPA's decision. EPA's
brief and the Court's decision are included in the administrative
record for today's rule.
EPA has undertaken significant effort toward completion of the
dioxin reassessment. On September 13, 1994, EPA released for public
review and comment a draft reassessment of toxicity and exposure to
dioxin. See Health Assessment Document for 2,3,7,8-Tetrachlorobenzo-p-
Dioxin (TCDD) and Related Compounds, U.S. EPA, 1994. EPA is currently
addressing comments made by the public and the SAB and anticipates that
the final
[[Page 31696]]
revised reassessment will go to the SAB in the near future. With
today's rule, the Agency reaffirms that, notwithstanding the on-going
risk reassessment, EPA intends to continue to regulate dioxin to avoid
further harm to public health, and the basis for the dioxin criteria,
both in terms of the cancer potency and the exposure estimates, remains
scientifically defensible. The fact that EPA is reassessing the risk of
dioxin, virtually a continuous process to evaluate new scientific
information, does not mean that the current risk assessment is
``wrong''. It continues to be EPA's position that until the risk
assessment for dioxin is revised, EPA supports and will continue to use
the existing risk assessment for the regulation of dioxin in the
environment. Accordingly, EPA today promulgates dioxin criteria based
on the 1984 criteria guidance document for dioxin and promulgated in
the NTR in 1992.
Toxicity Equivalency: The State of California, in its 1991 water
quality control plans, adopted human health criteria for dioxin and
dioxin-like compounds based on the concept of toxicity equivalency
(TEQ) using toxicity equivalency factors (TEFs). EPA Region 9 reviewed
and approved the State's use of the TEQ concept and TEFs in setting the
State's human health water quality criteria for dioxin and dioxin-like
compounds.
In 1987, EPA formally embraced the TEQ concept as an interim
procedure to estimate the risks associated with exposures to 210
chlorinated dibenzo-p-dioxin and chlorinated dibenzofuran (CDD/CDF)
congeners, including 2,3,7,8-TCDD. This procedure uses a set of derived
TEFs to convert the concentration of any CDD/CDF congener into an
equivalent concentration of 2,3,7,8-TCDD. In 1989, EPA updated its TEFs
based on an examination of relevant scientific evidence and a
recognition of the value of international consistency. This updated
information can be found in EPA's 1989 Update to the Interim Procedures
for Estimating Risks Associated with Exposures to Mixtures of
Chlorinated Dibenzo-p-dioxins and -dibenzofurans (CDDs and CDFs) (EPA/
625/3-89/016, March 1989). EPA had been active in an international
effort aimed at adopting a common set of TEFs (International TEFs/89 or
I-TEFs/89), to facilitate information exchange on environmental
contamination of CDD/CDF. This document reflects EPA's support of an
internationally consistent set of TEFs, the I-TEFs/89. EPA uses I-TEFs/
89 in many of its regulatory programs.
In 1994, the World Health Organization (WHO) revised the TEF scheme
for dioxins and furans to include toxicity from dioxin-like compounds
(Ahlborg et al., 1994). However, no changes were made to the TEFs for
dioxins and furans. In 1998, the WHO re-evaluated and revised the
previously established TEFs for dioxins (Ds), furans (Fs) and dioxin-
like compounds (Vanden Bers, 1998). The nomenclature for this TEF
scheme is TEQDFP-WHO98, where TEQ represents the 2,3,7,8-TCDD Toxic
Equivalence of the mixture, and the subscript DFP indicates that
dioxins (Ds) furans (Fs) and dioxin-like compounds (P) are included in
the TEF scheme. The subscript 98 following WHO displays the year
changes were made to the TEF scheme.
EPA intends to use the 1998 WHO TEF scheme in the near future. At
this point however, EPA will support the use of either the 1989 interim
procedures or the 1998 WHO TEF scheme but encourages the use of the
1998 WHO TEF scheme in State programs. EPA expects California to use a
TEF scheme in implementing the 2,3,7,8-TCDD water quality criteria
contained in today's rule. The TEQ and TEF approach provide a
methodology for setting NPDES water quality-based permit limits that
are protective of human health for dioxin and dioxin-like compounds.
Several commenters requested EPA to promulgate criteria for other
forms of dioxin, in addition to 2,3,7,8-TCDD. EPA's draft reassessment
for dioxin examines toxicity based on the TEQ concept and I-TEFs/89.
When EPA completes the dioxin reassessment, the Agency intends to adopt
revised 304(a) water quality criteria guidance based on the
reassessment for dioxin. If necessary, EPA will then act to amend the
NTR and CTR to reflect the revised 304(a) water quality criteria
guidance.
b. Arsenic Criteria
EPA is not promulgating human health criteria for arsenic in
today's rule. EPA recognizes that it promulgated human health water
quality criteria for arsenic for a number of States in 1992, in the
NTR, based on EPA's 1980 section 304(a) criteria guidance for arsenic
established, in part, from IRIS values current at that time. However, a
number of issues and uncertainties existed at the time of the CTR
proposal concerning the health effects of arsenic. These issues and
uncertainties were summarized in ``Issues Related to Health Risk of
Arsenic'' which is contained in the administrative record for today's
rule. During the period of this rulemaking action, EPA commissioned a
study of arsenic health effects by the National Research Council (NRC)
arm of the National Academy of Sciences. EPA received the NRC report in
March of 1999. EPA scientists reviewed the report, which recommended
that EPA lower the Safe Drinking Water Act arsenic maximum contaminant
level (MCL) as soon as possible (The arsenic MCL is currently 50
µg/l.) The bladder cancer analysis in the NRC report will
provide part of the basis for the risk assessment of a proposed revised
arsenic MCL in the near future. After promulgating a revised MCL for
drinking water, the Agency plans to revise the CWA 304(a) human health
criteria for arsenic in order to harmonize the two standards. Today's
rule defers promulgating arsenic criteria based on the Agency's
previous risk assessment of skin cancer. In the meantime, permitting
authorities in California should rely on existing narrative water
quality criteria to establish effluent limitations as necessary for
arsenic. California has previously expressed its science and policy
position by establishing a criterion level of 5 µg/l for
arsenic. Permitting authorities may, among other considerations,
consider that value when evaluating and interpreting narrative water
quality criteria.
c. Mercury Criteria
The human health criteria promulgated here use the latest RfD in
EPA's Integrated Risk Information System (IRIS) and the weighted
average practical bioconcentration factor (PBCF) from the 1980 section
304(a) criteria guidance document for mercury. EPA considered the
approach used in the Great Lakes Water Quality Guidance (``Guidance'')
incorporating Bioaccumulation Factors (BAFs), but rejected this
approach for reasons outlined below. The equation used here to derive
an ambient water quality criterion for mercury from exposure to
organisms and water is:
[GRAPHIC] [TIFF OMITTED] TR18MY00.011
Where:
RfD = Reference Dose
BW = Body Weight
WC = Water Consumption
FC = Total Fish and Shellfish Consumption per Day
PBCF = Practical Bioconcentration Factor (weighted average)
For mercury, the most current RfD from IRIS is 1 x 10-4
mg/kg/day. The RfD used a benchmark dose as an estimate of a No
Observed Adverse Effect Level (NOAEL). The benchmark dose was
calculated by applying a Weibel model
[[Page 31697]]
for extra risk to all neurological effects observed in 81 Iraqi
children exposed in utero as reported in Marsh, et. al. (1987).
Maternal hair mercury was the measure of exposure. Extra risk refers to
an adjustment for background incidence of a given health effect.
Specifically, the extra risk is the added incidence of observing an
effect above the background rate relative to the proportion of the
population of interest that is not expected to exhibit such as effect.
The resulting estimate was the lower 95% statistical bound on the 10%
extra risk; this was 11 ppm mercury in maternal hair. This dose in hair
was converted to an equivalent ingested amount by applying a model
based on data from human studies; the resulting benchmark dose was 1 x
10-3 mg/kg body weight /day. The RfD was calculated by
dividing the benchmark dose by a composite uncertainty factor of 10.
The uncertainty factor was used to account for variability in the human
population, in particular the wide variation in biological half-life of
methylmercury and the variation that is observed in the ration of hair
mercury to mercury in the blood. In addition the uncertainty factor
accounts for lack of a two-generation reproductive study and the lack
of data on long term effects of childhood mercury exposures. The RfD
thus calculated is 1 x 10-4 mg/kg body weight/day or 0.1
µg/kg/day. The body weight used in the equation for the mercury
criteria, as discussed in the Human Health Guidelines, is a mean adult
human body weight of 70 kg. The drinking water consumption rate, as
discussed in the Human Health Guidelines, is 2.0 liters per day.
The bioconcentration factor or BCF is defined as the ratio of
chemical concentration in the organism to that in surrounding water.
Bioconcentration occurs through uptake and retention of a substance
from water only, through gill membranes or other external body
surfaces. In the context of setting exposure criteria it is generally
understood that the terms ``BCF'' and ``steady-state BCF'' are
synonymous. A steady-state condition occurs when the organism is
exposed for a sufficient length of time that the ratio does not change
substantially.
The BCFs that were used herein are the ``Practical Bioconcentration
Factors (PBCFs)'' that were derived in 1980: 5500 for fresh water, 3765
for estuarine coastal waters, and 9000 for open oceans. See pages C-
100-1 of Ambient Water Quality Criteria for Mercury (EPA 440/5-80-058)
for a complete discussion on the PBCF. Because of the way they were
derived, these PBCFs take into account uptake from food as well as
uptake from water. A weighted average PBCF was calculated to take into
account the average consumption from the three waters using the
following equation:
[GRAPHIC] [TIFF OMITTED] TR18MY00.012
Given the large value for the weighted average PBCF, the contribution
of drinking water to total daily intake is negligible so that
assumptions concerning the chemical form of mercury in drinking water
become less important. The human health mercury criteria promulgated
for this rule are based on the latest RfD as listed in IRIS and a
weighted PBCF from the 1980 Sec. 304(a) criteria guidance document for
mercury.
On March 23, 1995 (60 FR 15366), EPA promulgated the Great Lakes
Water Quality Guidance (``Guidance''). The Guidance incorporated
bioaccumulation factors (BAFs) in the derivation of criteria to protect
human health because it is believed that BAFs are a better predictor
than BCFs of the concentration of a chemical within fish tissue since
BAFs include consideration of the uptake of contaminants from all
routes of exposure. A bioaccumulation factor is defined as the ratio
(in L/kg) of a substance's concentration in tissue to the concentration
in the ambient water, in situations where both the organism and its
food are exposed and the ratio does not change substantially over time.
The final Great Lakes Guidance establishes a hierarchy of four methods
for deriving BAFs for non-polar organic chemicals: (1) Field-measured
BAFs; (2) predicted BAFs derived using a field-measured biota-sediment
accumulation factor; (3) predicted BAFs derived by multiplying a
laboratory-measured BCF by a food chain multiplier; and (4) predicted
BAFs derived by multiplying a BCF calculated from the log Kow by a
food-chain multiplier. The final Great Lakes Guidance developed BAFs
for trophic levels three and four fish of the Great Lakes Basin.
Respectively, the BAFs for mercury for trophic level 3 and 4 fish were:
27,900 and 140,000.
The BAF promulgated in the GLI was developed specifically for the
Great Lakes System. It is uncertain whether the BAFs of 27,900 and
140,000 are appropriate for use in California at this time; therefore,
today's final rule does not use the GLI BAF in establishing human
health criteria for mercury in California. The magnitude of the BAF for
mercury in a given system depends on how much of the total mercury is
present in the methylated form. Methylation rates vary widely from one
water body to another for reasons that are not fully understood.
Lacking the data, it is difficult to determine if the BAF used in the
GLI represents the true potential for mercury to bioaccumulate in
California surface waters. The true, average BAF for California could
be higher or lower. For more information see EPA's Response to Comments
document in the administrative record for this rule (specifically
comments CTR-002-007(b) and CTR-016-007).
EPA is developing a national BAF for mercury as part of revisions
to its 304(a) criteria for human health; however, the BAF methodology
that will be used is currently under evaluation as part of EPA's
revisions to its National Human Health Methodology (see section F.3
above). EPA applied a similar methodology in its Mercury Study Report
to Congress (MSRC) to derive a BAF for methylmercury. The MSRC is
available through NTIS (EPA-452/R-97-003). Although a BAF was derived
in the MSRC, EPA does not intend to use this BAF for National
application. EPA is engaged in a separate effort to incorporate
additional mercury bioaccumulation data that was not considered in the
MSRC, and to assess uncertainties with using a National BAF approach
for mercury. Once the proposed revised human health methodology,
including the BAF component, is finalized, EPA will revise its 304(a)
criteria for mercury to reflect changes in the underlying methodology,
recommendations contained in the MSRC, and recommendations in a
National Academy of Science report on human health assessment of
methylmercury. When EPA changes its 304(a) criteria recommendation for
mercury, States and Tribes will be expected to review their water
quality standards for mercury and make any revisions necessary to
ensure their standards are scientifically defensible.
New information may become available regarding the bioaccumulation
[[Page 31698]]
of mercury in certain water bodies in California. EPA supports the use
of this information to develop site-specific criteria for mercury.
Further, if a California water body is impaired due to mercury fish
tissue or sediment contamination, loadings of mercury could contribute
to or exacerbate the impairment. Therefore, one option regulatory
authorities should consider is to include water quality-based effluent
limits (WQBELs) in permits based on mass for discharges to the impaired
water body. Such WQBELs must be derived from and comply with applicable
State water quality standards (including both numeric and narrative
criteria) and assure that the discharge does not cause or contribute to
a violation of water quality standards.
d. Polychlorinated Biphenyls (PCBs) Criteria
The NTR, as amended, calculated human health criteria for PCBs
using a cancer potency factor of 7.7 per mg/kg-day from the Agency's
IRIS. This cancer potency factor was derived from the Norback and
Weltman (1985) study which looked at rats that were fed Aroclor 1260.
The study used the linearized multistage model with a default cross-
species scaling factor (body weight ratio to the \2/3\ power). Although
it is known that PCB mixtures vary greatly as to their potency in
producing biological effects, for purposes of its carcinogenicity
assessment, EPA considered Aroclor 1260 to be representative of all PCB
mixtures. The Agency did not pool data from all available congener
studies or generate a geometric mean from these studies, since the
Norback and Weltman study was judged by EPA as acceptable, and not of
marginal quality, in design or conduct as compared with other studies.
Thereafter, the Institute for Evaluating Health Risks (IEHR, 1991)
reviewed the pathological slides from the Norback and Weltman study,
and concluded that some of the malignant liver tumors should have been
interpreted as nonmalignant lesions, and that the cancer potency factor
should be 5.1 per mg/kg-day as compared with EPA's 7.7 per mg/kg-day.
The Agency's peer-reviewed reassessment of the cancer potency of
PCBs published in a final report, PCBs: Cancer Dose-Response Assessment
and Applications to Environmental Mixtures (EPA/600/P-96/001F), adopts
a different approach that distinguishes among PCB mixtures by using
information on environmental processes. (The report is included in the
administrative record of today's rule.) The report considers all cancer
studies (which used commercial mixtures only) to develop a range of
cancer potency factors, then uses information on environmental
processes to provide guidance on choosing an appropriate potency factor
for representative classes of environmental mixtures and different
pathways. The reassessment provides that, depending on the specific
application, either central estimates or upper bounds can be
appropriate. Central estimates describe a typical individual's risk,
while upper bounds provide assurance (i.e., 95% confidence) that this
risk is not likely to be underestimated if the underlying model is
correct. Central estimates are used for comparing or ranking
environmental hazards, while upper bounds provide information about the
precision of the comparison or ranking. In the reassessment, the use of
the upper bound values were found to increase cancer potency estimates
by two or three-fold over those using central tendency. Upper bounds
are useful for estimating risks or setting exposure-related standards
to protect public health, and are used by EPA in quantitative cancer
risk assessment. Thus, the cancer potency of PCB mixtures is determined
using a tiered approach based on environmental exposure routes with
upper-bound potency factors (using a body weight ratio to the \3/4\
power) ranging from 0.07 (lowest risk and persistence) to 2 (high risk
and persistence) per mg/kg-day for average lifetime exposures to PCBs.
It is noteworthy that bioaccumulated PCBs appear to be more toxic than
commercial PCBs and appear to be more persistent in the body. For
exposure through the food chain, risks can be higher than other
exposures.
EPA issued the final reassessment report on September 27, 1996, and
updated IRIS to include the reassessment on October 1, 1996. EPA
updated the human health criteria for PCBs in the National Toxics Rule
on September 27, 1999. For today's rule, EPA derived the human health
criteria for PCBs using a cancer potency factor of 2 per mg/kg-day, an
upper bound potency factor reflecting high risk and persistence. This
decision is based on recent multimedia studies indicating that the
major pathway of exposure to persistent toxic substances such as PCBs
is via dietary exposure (i.e., contaminated fish and shellfish
consumption).
Following is the calculation of the human health criterion (HHC)
for organism and water consumption:
[GRAPHIC] [TIFF OMITTED] TR18MY00.013
Where:
RF = Risk Factor = 1 x 10-6
BW = Body Weight = 70 kg
q1* = Cancer slope factor = 2 per mg/kg-day
WC = Water Consumption = 2 l/day
FC = Fish and Shellfish Consumption = 0.0065 kg/day
BCF = Bioconcentration Factor = 31,200
the HHC (µg/l) = 0.00017 µg/l (rounded to two
significant digits).
Following is the calculation of the human health criterion for
organism only consumption:
[GRAPHIC] [TIFF OMITTED] TR18MY00.014
Where:
RF = Risk Factor = 1 x 10-6
BW = Body Weight = 70 kg
q1* = Cancer slope factor = 2 per mg/kg-day
FC = Total Fish and Shellfish Consumption per Day = 0.0065 kg/day
BCF = Bioconcentration Factor = 31,200
the HHC (µg/l) = 0.00017 µg/l (rounded to two
significant digits).
The criteria are both equal to 0.00017 µg/l and apply to
total PCBs. See PCBs: Cancer Dose Response Assessment and Application
to Environmental Mixtures (EPA/600/9-96-001F). For a discussion of the
body weight, water consumption, and fish and shellfish consumption
factors, see the Human Health Guidelines. For a discussion of the BCF,
see the 304(a) criteria guidance document for PCBs (included in the
administrative record for today's rule).
e. Excluded Section 304(a) Human Health Criteria
As is the case in the NTR, as amended, today's rule does not
promulgate criteria for certain priority pollutants for which CWA
section 304(a) criteria guidance exists because those criteria were not
based on toxicity to humans or aquatic organisms. The basis for those
particular criteria is organoleptic effects (e.g., taste and odor)
which would make water and edible aquatic life unpalatable but not
toxic. Because the basis for this rule is to protect the public health
and aquatic life from toxicity consistent with the language and intent
in CWA section 303(c)(2)(B), EPA is promulgating criteria only for
those priority toxic pollutants whose criteria recommendations are
based on toxicity. The CWA section 304(a) human health criteria based
on organoleptic effects for zinc and 3-methyl-4-chlorophenol are
excluded for this reason. See the 1992 NTR discussion at 57 FR 60864.
[[Page 31699]]
f. Cancer Risk Level
EPA's CWA section 304(a) criteria guidance documents for priority
toxic pollutants that are based on carcinogenicity present
concentrations for upper bound risk levels of 1 excess cancer case per
100,000 people (10-5), per 1,000,000 people
(10-6), and per 10,000,000 people (10-7).
However, the criteria documents do not recommend a particular risk
level as EPA policy.
As part of the proposed rule, EPA requested and received comment on
the adoption of a 10 -5 risk level for carcinogenic
pollutants. The effect of a 10-5 risk level would have been
to increase (i.e., make less stringent) carcinogenic pollutant criteria
values (noted in the matrix by footnote c) that are not already
promulgated in the NTR, by one order of magnitude. For example, the
organism-only criterion for gamma BHC (pollutant number 105 in the
matrix) is 0.013 µg/l; the criterion based on a 10-5
risk level would have been 0.13 µg/l. EPA received several
comments that indicated a preference for a higher (10-4 and
10-5) risk level for effluent dependent waters or other
types of special circumstances.
In today's rule, EPA is promulgating criteria that protect the
general population at an incremental cancer risk level of one in a
million (10-6) for all priority toxic pollutants regulated
as carcinogens, consistent with the criteria promulgated in the NTR for
the State of California. Standards adopted by the State contained in
the Enclosed Bays and Estuaries Plan (EBEP), and the Inland Surface
Waters Plan (ISWP), partially approved by EPA on November 6, 1991, and
the Ocean Plan approved by EPA on June 28, 1990, contained a risk level
of 10-6 for most carcinogens. The State has historically
protected at a 10-6 risk level for carcinogenic pollutants.
EPA, in its recent human health methodology revisions, proposed
acceptable lifetime cancer risk for the general population in the range
of 10-5 to 10-6. EPA also proposed that States
and Tribes ensure the most highly exposed populations do not exceed a
10-4 risk level. However, EPA's draft methodology revisions
also stated that it will derive 304(a) criteria at a 10-6
risk level, which the Agency believes reflects the appropriate risk for
the general population and which applies a risk management policy which
ensures protection for all exposed population groups. (Draft Water
Quality Criteria Methodology: Human Health, EPA 822-Z-98-001, August
1998, Appendix II, page 72).
Subpopulations within a State may exist, such as recreational and
subsistence anglers, who as a result of greater exposure to a
contaminant are at greater risk than the standard 70 kilogram person
eating 6.5 grams per day of fish and shellfish and drinking 2.0 liters
per day of drinking water with pollutant levels meeting the water
quality criteria. EPA acknowledges that at any given risk level for the
general population, those segments of the population that are more
highly exposed face a higher relative risk. For example, if fish are
contaminated at a level permitted by criteria derived on the basis of a
risk level of 10-6, individuals consuming up to 10 times the
assumed fish consumption rate would still be protected at a
10-5 risk level. Similarly, individuals consuming 100 times
the general population rate would be protected at a 10-4
risk level. EPA, therefore, believes that derivation of criteria at the
10-6 risk level is a reasonable risk management decision
protective of designated uses under the CWA. While outside the scope of
this rule, EPA notes that States and Tribes, however, have the
discretion to adopt water quality criteria that result in a higher risk
level (e.g., 10-5). EPA expects to approve such criteria if
the State or Tribe has identified the most highly exposed subpopulation
within the State or Tribe, demonstrates the chosen risk level is
adequately protective of the most highly exposed subpopulation, and has
completed all necessary public participation.
This demonstration has not happened in California. Further, the
information that is available on highly exposed subpopulations in
California supports the need to protect the general population at the
10-6 level. California has cited the Santa Monica Bay
Seafood Consumption Study as providing the best available data set for
estimating consumption of sport fish and shellfish in California for
both marine or freshwater sources (Chemicals in Fish Report No. 1:
Consumption of Fish and Shellfish in California and the United States,
Final Draft Report, July 1997). Consumption rates of sport fish and
shellfish of 21g/day, 50 g/day, 107 g/day, and 161 g/day for the
median, mean, 90th, and 95th percentile rates, respectively, were
determined from this study. Additional consumption of commercial
species in the range of approximately 8 to 42 g/day would further
increase these values. Clearly the consumption rates for the most
highly exposed subpopulation within the State exceeds 10 times the 6.5
g/day rates used in the CTR. Therefore, use of a risk level of
10-5 for the general population would not be sufficient to
protect the most highly exposed population in California at a
10-4 risk level. On the other hand, even the most highly
exposed subpopulations cited in the California study do not have
consumption rates approaching 100 times the 6.5 g/day rates used in the
CTR. The use of the 10-6 risk level to protect average level
consumers does not subject these subpopulations to risk levels as high
as 10-4.
EPA believes its decision to establish a 10-6 risk level
for the CTR is also consistent with EPA's policy in the NTR to select
the risk level that reflect the policies or preferences of CWA programs
in the affected States. California adopted standards for priority toxic
pollutants for its ocean waters in 1990 using a 10-6 risk
level to protect human health (California Ocean Plan, 1990). In April
1991, and again in November 1992, California adopted standards for its
inland surface waters and enclosed bays and estuaries in its Inland
Surface Waters Plan (ISWP) and its Enclosed Bays and Estuaries Plan
(EBEP) using a 10-6 risk level. To be consistent with the
State's water quality standards, EPA used a 10-6 risk level
for California in the NTR at 57 FR 60867. The State has continued using
a 10-6 risk level to protect human health for its standards
that were not withdrawn with the ISWP and EBEP. The most recent
expression of risk level preference is contained in the Draft
Functional Equivalent Document, Amendment of the Water Quality Control
Plan for Ocean Waters of California, October 1998, where the State
recommended maintaining a consistent risk level of 10-6 for
the human health standards that it was proposing to revise.
EPA received several comments requesting a 10-5 risk
level based on the risk level chosen for the Great Lakes Water Quality
Guidance (the Guidance). There are several differences between the
guidelines for the derivation of human health criteria contained in the
Guidance and the California Toxics Rule (CTR) that make a
10-5 risk factor appropriate for the Guidance, but not for
the CTR. These differences result in criteria developed using the
10-5 risk factor in the Guidance being at least as stringent
as criteria derived under the CTR using a 10-6 risk factor.
The relevant aspects of the Guidance include:
Use of fish consumption rates that are considerably higher
than fish consumption rates for the CTR.
Use of bioaccumulation factors rather than
bioconcentration factors in
[[Page 31700]]
estimating exposure, considerably increasing the dose of carcinogens to
sensitive subgroups.
Consideration of additivity of effects of mixtures for
both carcinogenic and noncarcinogenic pollutants.
This combination of factors increase the calculated carcinogenic
risk substantially under the Guidance (the combination would generally
be more than one order of magnitude), making a lower overall risk
factor acceptable. The Guidance risk factor provides, in fact, criteria
with at least the same level of protection against carcinogens as
criteria derived with a higher risk factor using the CTR. A lower risk
factor for the CTR would not be appropriate absent concomitant changes
in the derivation procedures that provide equivalent risk protection.
G. Description of Final Rule
1. Scope
Paragraph (a) in 40 CFR 131.38, entitled ``Scope,'' states that
this rule is a promulgation of criteria for priority toxic pollutants
in the State of California for inland surface waters, enclosed bays,
and estuaries. Paragraph (a) in 40 CFR 131.38 also states that this
rule contains an authorizing compliance schedule provision.
2. EPA Criteria for Priority Toxic Pollutants
EPA's criteria for California are presented in tabular form at 40
CFR 131.38. For ease of presentation, the table that appears combines
water quality criteria promulgated in the NTR, as amended, that are
outside the scope of this rulemaking, with the criteria that are within
the scope of today's rule. This is intended to help readers determine
applicable water quality criteria for the State of California. The
table contains footnotes for clarification.
Paragraph (b) in 40 CFR 131.38 presents a matrix of the applicable
EPA aquatic life and/or human health criteria for priority toxic
pollutants in California. Section 303(c)(2)(B) of the CWA addresses
only pollutants listed as ``toxic'' pursuant to section 307(a) of the
CWA for which EPA has developed section 304(a) criteria guidance. As
discussed earlier in this preamble, the section 307(a) list of toxics
contains 65 compounds and families of compounds, which potentially
include thousands of specific compounds. Of these, the Agency
identified a list of 126 ``priority toxic pollutants'' to implement the
CWA (see 40 CFR 131.36(b)). Reference in this rule to priority toxic
pollutants, toxic pollutants, or toxics refers to the 126 priority
toxic pollutants.
EPA has not developed both aquatic life and human health CWA
section 304(a) criterion guidance for all of the priority toxic
pollutants. The matrix in 40 CFR 131.38(b) contains human health
criteria in Column D for 92 priority toxic pollutants which are divided
into Column 1: criteria for water consumption (i.e., 2.0 liters per
day) and aquatic organism consumption (i.e., 6.5 grams per day of
aquatic organisms); and Column 2: criteria for aquatic organism
consumption only. The term aquatic organism includes fish and shellfish
such as shrimp, clams, oysters and mussels. One reason the total number
of priority toxic pollutants with criteria today differs from the total
number of priority toxic pollutants contained in earlier published CWA
section 304(a) criteria guidance is because EPA has developed and is
promulgating chromium criteria for two valence states with respect to
aquatic life criteria. Thus, although chromium is a single priority
toxic pollutant, there are two criteria for chromium for aquatic life
protection. See pollutant 5 in today's rule at 40 CFR 131.38(b).
Another reason is that EPA is promulgating human health criteria for
nine priority pollutants for which health-based national criteria have
been calculated based on information obtained from EPA's IRIS database
(EPA provided notice of these nine criteria in the NTR for inclusion in
future State triennial reviews. See 57 FR 60848, 60890).
The matrix contains aquatic life criteria for 23 priority
pollutants. These are divided into freshwater criteria (Column B) and
saltwater criteria (Column C). These columns are further divided into
acute and chronic criteria. The aquatic life criteria are considered by
EPA to be protective when applied under the conditions described in the
section 304(a) criteria documents and in the TSD. For example, water
body uses should be protected if the criteria are not exceeded, on
average, once every three year period. It should be noted that the
criteria maximum concentrations (the acute criteria) are short-term
concentrations and that the criteria continuous concentrations (the
chronic criteria) are four-day averages. It should also be noted that
for certain metals, the actual criteria are equations which are
included as footnotes to the matrix. The toxicity of these metals is
water hardness dependent and may be adjusted. The values shown in the
table are illustrative only, based on a hardness expressed as calcium
carbonate of 100 mg/l. Finally, the criterion for pentachlorophenol is
pH dependent. The equation is the actual criterion and is included as a
footnote. The value shown in the matrix is for a pH of 7.8. Several of
the freshwater aquatic life criteria are incorporated into the matrix
in the format used in the 1980 criteria methodology which uses a final
acute value instead of a continuous maximum concentration. This
distinction is noted in footnote g of the table.
The final rule at 40 CFR 131.38(c) establishes the applicability of
the criteria to the State of California. 40 CFR 131.38(d) is described
later in Section F, of this preamble. EPA has included in this rule
provisions necessary to implement numeric criteria in a way that
maintains the level of protection intended. These provisions are
included in 40 CFR 131.38(c) of today's rule. For example, in order to
do steady state waste load allocation analyses, most States have low
flow values for streams and rivers which establish flow rates for
various purposes. These low flow values become design flows for sizing
treatment plants and developing water quality-based effluent limits
and/or TMDLs. Historically, these design flows were selected for the
purposes of waste load allocation analyses which focused on instream
dissolved oxygen concentrations and protection of aquatic life. With
the publication of the 1985 TSD, EPA introduced hydrologically and
biologically based analyses for the protection of aquatic life and
human health. (These concepts have been expanded subsequently in EPA's
Technical Guidance Manual for Performing Wasteload Allocations, Book 6,
Design Conditions, U.S. EPA, 1986. These analyses are included in
Appendix D of the revised TSD. The discussion here is greatly
simplified and is provided to support EPA's decision to promulgate
design flows for instream flows and thereby maintain the adequacy of
the criteria for priority toxic pollutants.) EPA recommended either of
two methods for calculating acceptable low flows, the traditional
hydrologic method developed by the U.S. Geological Survey or a
biological based method developed by EPA. Other methods for evaluating
the instream flow record may be available; use of these methods may
result in TMDLs and/or water quality-based effluent limitations which
adequately protect human health and/or aquatic life. The results of
either of these two methods, or an equally protective alternative
method, may be used.
The State of California may adopt specific design flows for streams
and rivers to protect designated uses against the effects of toxics.
EPA believes it is
[[Page 31701]]
important to specify design flows in today's rule so that, in the
absence of state design flows, the criteria promulgated today would be
implemented appropriately. The TSD also recommends the use of three
dynamic models to perform wasteload allocations. Dynamic wasteload
models do not generally use specific steady state design flows but
accomplish the same effect by factoring in the probability of
occurrence of stream flows based on the historical flow record.
The low flows specified in the rule explicitly contain duration and
frequency of occurrence which represent certain probabilities of
occurrence. Likewise, the criteria for priority toxic pollutants are
defined with duration and frequency components. Dynamic modeling
techniques explicitly predict the effects of variability in receiving
water, effluent flow, and pollution variation. Dynamic modeling
techniques, as described in the TSD, allow for calculating wasteload
allocations that meet the criteria for priority toxic pollutants
without using a single, worst-case concentration based on a critical
condition. Either dynamic modeling or steady state modeling can be used
to implement the criteria promulgated today. For simplicity, only
steady state conditions are discussed here. Clearly, if the criteria
were implemented using design flows that are too high, the resulting
toxic controls would not be adequate, because the resulting ambient
concentrations would exceed EPA's criteria.
In the case of aquatic life, assuming exceedences occur more
frequently than once in three years on the average, exceedences would
result in diminished vitality of stream ecosystems characterized by the
loss of desired species. Numeric water quality criteria should apply at
all flows that are equal to or greater than flows specified below. The
low flow values are:
------------------------------------------------------------------------
Type of criteria Design flow
------------------------------------------------------------------------
Acute Aquatic Life (CMC).................. 1 Q 10 or 1 B 3
Chronic Aquatic Life (CCC)................ 7 Q 10 or 4 B 3
Human Health.............................. harmonic mean flow
------------------------------------------------------------------------
Where:
1 Q 10 is the lowest one day flow with an average recurrence frequency
of once in 10 years determined hydrologically;
1 B 3 is biologically based and indicates an allowable exceedence of
once every 3 years. It is determined by EPA's computerized method
(DFLOW model);
7 Q 10 is the lowest average 7 consecutive day low flow with an average
recurrence frequency of once in 10 years determined hydrologically;
4 B 3 is biologically based and indicates an allowable exceedences for
4 consecutive days once every 3 years. It is determined by EPA's
computerized method (DFLOW model);
EPA is requiring that the harmonic mean flow be applied with human
health criteria. The harmonic mean is a standard calculated statistical
value. EPA's model for human health effects assumes that such effects
occur because of a long-term exposure to low concentration of a toxic
pollutant, for example, two liters of water per day for seventy years.
To estimate the concentrations of the toxic pollutant in those two
liters per day by withdrawal from streams with a high daily variation
in flow, EPA believes the harmonic mean flow is the correct statistic
to use in computing such design flows rather than other averaging
techniques. (For a description of harmonic means see ``Design Stream
Flows Based on Harmonic Means,'' Lewis A. Rossman, Jr. of Hydraulics
Engineering, Vol. 116, No. 7, July, 1990.)
All waters (including lakes, estuaries, and marine waters), whether
or not suitable for such hydrologic calculations, are subject to the
criteria promulgated today. Such criteria will need to be attained at
the end of the discharge pipe, unless the State authorizes a mixing
zone. Where the State plans to authorize a mixing zone, the criteria
would apply at the locations allowed by the mixing zone. For example,
the chronic criteria (CCC) would apply at the defined boundary of the
chronic mixing zone. Discussion of and guidance on these factors are
included in the revised TSD in Chapter 4.
EPA is aware that the criteria promulgated today for some of the
priority toxic pollutants are at concentrations less than EPA's current
analytical detection limits. Analytical detection limits have never
been an acceptable basis for setting water quality criteria since they
are not related to actual environmental impacts. The environmental
impact of a pollutant is based on a scientific determination, not a
measuring technique which is subject to change. Setting the criteria at
levels that reflect adequate protection tends to be a forcing mechanism
to improve analytical detection methods. See 1985 Guidelines, page 21.
As the methods improve, limits based on the actual criteria necessary
to protect aquatic life and human health become measurable. The Agency
does not believe it is appropriate to promulgate criteria that are not
sufficiently protective. EPA discusses this issue further in its
Response to Comment Document for today's final rule.
EPA does believe, however, that the use of analytical detection
limits are appropriate for assessing compliance with National Pollutant
Discharge Elimination System (NPDES) permit limits. This view of the
role of detection limits was first articulated in guidance for
translating dioxin criteria into NPDES permit limits. See ``Strategy
for the Regulation of Discharges of PHDDs and PHDFs from Pulp and Paper
Mills to Waters of the U.S.'' Memorandum from the Assistant
Administrator for Water to the Regional Water Management Division
Directors, May 21, 1990. This guidance presented a model for addressing
toxic pollutants which have criteria less than current detection
limits. EPA, in more recent guidance, recommends the use of the
``minimum level'' or ML for reporting sample results to assess
compliance with WQBELs (TSD page 111). The ML, also called the
``quantification level,'' is the level at which the entire analytical
system gives recognizable mass spectra and acceptable calibration
points, i.e., the point at which the method can reliably quantify the
amount of pollutant in the sample. States can use their own procedures
to average and otherwise account for monitoring data, e.g., quantifying
results below the ML. These results can then be used to assess
compliance with WQBELs. (See 40 CFR part 132, Appendix F, Procedure
8.B.) This approach is applicable to priority toxic pollutants with
criteria less than current detection limits. EPA's guidance explains
that standard analytical methods may be used for purposes of assessing
compliance with permit limits, but not for purposes of establishing
water quality criteria or permit limits. Under the CWA, analytical
methods are appropriately used in connection with NPDES permit limit
compliance assessments. Because of the function of water quality
criteria, EPA has not considered the sensitivity of analytical methods
in deriving the criteria promulgated today.
EPA has promulgated 40 CFR 131.38(c)(3) to determine when
freshwater or saltwater aquatic life criteria apply. This provision
incorporates a time parameter to better define the critical condition.
The structure of the paragraph is to establish
[[Page 31702]]
applicable rules and to allow for site-specific exceptions where the
rules are not consistent with actual field conditions. Because a
distinct separation generally does not exist between freshwater and
saltwater aquatic communities, EPA is establishing the following: (1)
The freshwater criteria apply at salinities of 1 part per thousand and
below at locations where this occurs 95% or more of the time; (2)
saltwater criteria apply at salinities of 10 parts per thousand and
above at locations where this occurs 95% more of the time; and (3) at
salinities between 1 and 10 parts per thousand the more stringent of
the two apply unless EPA approves the application of the freshwater or
saltwater criteria based on an appropriate biological assessment. The
percentiles included here were selected to minimize the chance of
overlap, that is, one site meeting both criteria. Determination of
these percentiles can be done by any reasonable means such as
interpolation between points with measured data or by the application
of calibrated and verified mathematical models (or hydraulic models).
It is not EPA's intent to require actual data collection at particular
locations.
In the brackish water transition zones of estuaries with varying
salinities, there generally will be a mix of freshwater and saltwater
species. Generally, therefore, it is reasonable for the more stringent
of the freshwater or saltwater criteria to apply. In evaluating
appropriate data supporting the alternative set of criteria, EPA will
focus on the species composition as its preferred method. This
assignment of criteria for fresh, brackish and salt waters was
developed in consultation with EPA's research laboratories at Duluth,
Minnesota and Narragansett, Rhode Island. The Agency believes such an
approach is consistent with field experience.
Paragraph (d) in 40 CFR 131.38 lists the designated water and use
classifications for which the criteria apply. The criteria are applied
to the beneficial use designations adopted by the State of California;
EPA has not promulgated any new use classifications in this rule.
Exceedences Frequency: In a water quality criterion for aquatic
life, EPA recommends an allowable frequency for excursions of the
criteria. See 1985 Guidelines, pages 11-13. This allowable frequency
provides an appropriate period of time during which the aquatic
community can recover from the effect of an excursion and then function
normally for a period of time before the next excursion. An excursion
is defined as an occurrence of when the average concentration over the
duration of the averaging period is above the CCC or the CMC. As
ecological communities are naturally subjected to a series of stresses,
the allowable frequency of pollutant stress may be set at a value that
does not significantly increase the frequency or severity of all
stresses combined. See also TSD, Appendix D. In addition, providing an
allowable frequency for exceeding the criterion recognizes that it is
not generally possible to assure that criteria are never exceeded.
(TSD, page 36.)
Based on the available data, today's rule requires that the acute
criterion for a pollutant be exceeded no more than once in three years
on the average. EPA is also requiring that the chronic criterion for a
pollutant be exceeded no more than once in three years on the average.
EPA acknowledges that States may develop allowable frequencies that
differ from these allowable frequencies, so long as they are
scientifically supportable, but believes that these allowable
frequencies are protective of the designated uses where EPA is
promulgating criteria.
The use of aquatic life criteria for developing water quality-based
effluent limits in permits requires the permitting official to use an
appropriate wasteload allocation model. (TSD, Appendix D-6.) As
discussed above, there are generally two methods for determining design
flows, the hydrologically-based method and the biologically-based
method.
The biologically-based method directly uses the averaging periods
and frequencies specified in the aquatic life criteria for determining
design flows. (TSD, Appendix. D-8.) Because the biologically-based
method calculates the design flow directly from the duration and
allowable frequency, it most accurately provides the allowed number of
excursions. The hydrologically based method applies the CMC at a design
flow equal to or equivalent to the 1Q10 design flow (i.e., the lowest
one-day flow with an average recurrence frequency of once in ten
years), and applies the CCC at the 7Q10 design flow (i.e., the lowest
average seven consecutive day flow with a recurrence frequency of once
in ten years).
EPA established a three year allowable frequency in the NTR. In
settlement of the litigation on the NTR, EPA stated that it was in the
midst of conducting, sponsoring, or planning research aimed at
addressing scientific issues related to the basis for and application
of water quality criteria and mentioned the issue of allowable
frequency. See Partial Settlement Agreement in American Forest and
Paper Ass'n, Inc. et al. v. U.S. EPA (Consolidated Case No. 93-0694
(RMU) D.D.C. To that end, EPA is reevaluating issues raised about
allowable frequency as part of its work in revising the 1985
Guidelines.
EPA recognizes that additional data concerning (a) the probable
frequency of lethal events for an assemblage of taxa covering a range
of sensitivities to pollutants, (b) the probable frequency of sublethal
effects for such taxa, (c) the differing effects of lethal and
sublethal events in reducing populations of such taxa, and (d) the time
needed to replace organisms lost as a result of toxicity, may lead to
further refinement of the allowable frequency value. EPA has not yet
completed this work. Until this work is complete, EPA believes that
where EPA promulgates criteria, the three year allowable frequency
represents a value in the reasonable range for this parameter.
3. Implementation
Once the applicable designated uses and water quality criteria for
a water body are determined, under the National Pollutant Discharge
Elimination System (NPDES) program discharges to the water body must be
characterized and the permitting authority must determine the need for
permit limits. If a discharge causes, has the reasonable potential to
cause, or contributes to an excursion of a numeric or narrative water
quality criteria, the permitting authority must develop permit limits
as necessary to meet water quality standards. These permit limits are
water quality-based effluent limitations or WQBELs. The terms
``cause,'' ``reasonable potential to cause,'' and ``contribute to'' are
the terms in the NPDES regulations for conditions under which water
quality-based permit limits are required. See 40 CFR 122.44(d)(1).
Since the publication of the proposed CTR, the State of California
adopted procedures which detail how water quality criteria will be
implemented through NPDES permits, waste discharge requirements, and
other regulatory approaches. These procedures entitled, Policy for
Implementation of Toxics Standards for Inland Surface Waters, Enclosed
Bays, and Estuaries of California were adopted on March 2, 2000. Once
these procedures are submitted for review under CWA section 303(c), EPA
will review them as they relate to water quality standards, and approve
or disapprove them.
Several commenters understood the language in the preamble to the
proposed rule regarding implementation
[[Page 31703]]
to mean that site-specific criteria, variances, and other actions would
be prohibited or severely limited by the CTR. Site-specific criteria,
variances and other actions modifying criteria are neither prohibited
nor limited by the CTR. The State, if it so chooses, still can make
these changes to its water quality standards, subject to EPA approval.
However, with this Federal rule in effect, the State cannot implement
any modifications that are less stringent than the CTR without an
amendment to the CTR to reflect these modifications. EPA will make
every effort to expeditiously accommodate Federal rulemaking of
appropriate modifications to California's water quality standards. In
the preamble to the proposed CTR, and here today, EPA is emphasizing
that these efforts to amend the CTR on a case-by-case basis will
generally increase the time before a modification can be implemented.
4. Wet Weather Flows
EPA has for a longtime maintained that CWA section 301(b)(1)(C)
applies to NPDES permits for discharges from municipal separate storm
sewer systems. Recently, the U.S. Court of Appeals for the Ninth
Circuit upheld NPDES permits issued by EPA for five Arizona municipal
separate storm sewer systems and addressed this issue specifically.
Defenders of Wildlife, et al. v. Browner, No. 98-71080 (9th Cir.,
October 1999). The Court held that the CWA does not require ``strict
compliance'' with State water quality standards for municipal storm
sewer permits under section 301(b)(1)(C), but that at the same time,
the CWA does give EPA discretion to incorporate appropriate water
quality-based effluent limitations under another provision, CWA section
402(p)(3)(B)(iii).
The Court based its decision on the structure of section 402(p)(3),
which contains distinct language for discharges of industrial storm
water and municipal storm water. In section 402(p)(3)(A), Congress
requires that ``dischargers associated with industrial activity shall
meet all applicable provisions of [section 402] and section [301].'' 33
U.S.C. section 1342(p)(3)(A). The Court noted, therefore, that by
incorporation, industrial storm water discharges need to achieve ``any
more stringent limitation, including those necessary to meet water
quality standards * * *'' The Court explained that industrial storm
water discharges ``must comply strictly with State water quality
standards'' but that Congress chose not to include a similar provision
for municipal storm sewer discharges, including instead a requirement
for controls to reduce pollutants to the maximum extent practicable or
MEP standard in section 402(p)(3)(B). Reading the two related sections
together, the Court concluded that section 402(p)(3)(B)(iii) does not
require ``strict compliance'' by municipal storm sewer discharges
according to section 301(b)(1)(C). At the same time, however, the Court
found that the language in CWA section 402(p)(3)(B)(iii) which states
that permits for discharges from municipal storm sewers shall require
``such other provisions as the Administrator of the state determines
appropriate for the control of such pollutants'' provides EPA with
discretion to incorporate provisions lending to ultimate compliance
with water quality standards.
EPA believes that compliance with water quality standards through
the use of Best Management Practices (BMPs) is appropriate. EPA
articulated its position on the use of BMPs in storm water permits in
the policy memorandum entitled, ``Interim Permitting Approach for Water
Quality-Based Effluent Limitations In Storm Water Permits'' which was
signed by the Assistant Administrator for Water, Robert Perciasepe on
August 1, 1996 (61 FR 43761, August 9, 1996). A copy of this memorandum
is contained in the administrative record for today's rule. The policy
affirms the use of BMPs as a means to attain water quality standards in
municipal storm water permits, and embraces BMPs as an interim
permitting approach.
The interim permitting approach uses BMPs in first-round storm
water permits, and expanded or better-tailored BMPs in subsequent
permits, where necessary, to provide for the attainment of water
quality standards. In cases where adequate information exists to
develop more specific conditions or limitations to meet water quality
standards, these conditions or limitations are to be incorporated into
storm water permits, as necessary and appropriate.
This interim permitting approach, however, only applies to EPA. EPA
encourages the State to adopt a similar policy for municipal storm
water permits. This interim permitting approach provides time, where
necessary, to more fully assess the range of issues and possible
options for the control of storm water discharges for the protection of
water quality. More information on this issue is included in the
response to comment document in response to specific storm water issues
raised by commenters.
5. Schedules of Compliance
A compliance schedule refers to an enforceable sequence of interim
requirements in a permit leading to ultimate compliance with water
quality-based effluent limitations or WQBELs in accordance with the
CWA. The authorizing compliance schedule provision authorizes, but does
not require, the permit issuing authority in the State of California to
include such compliance schedules in permits under appropriate
circumstances. The State of California is authorized to administer the
National Pollutant Discharge Elimination System (NPDES) program and may
exercise its discretion when deciding if a compliance schedule is
justified because of the technical or financial (or other)
infeasibility of immediate compliance. An authorizing compliance
schedule provision is included in today's rule because of the potential
for existing dischargers to have new or more stringent effluent
limitations for which immediate compliance would not be possible or
practicable.
New and Existing Dischargers: The provision allows compliance
schedules only for an ``existing discharger'' which is defined as any
discharger which is not a ``new California discharger.'' A ``new
California discharger'' includes ``any building, structure, facility,
or installation from which there is, or may be, a `discharge of
pollutants', the construction of which commences after the effective
date of this regulation.'' These definitions are modeled after the
existing 40 CFR 122.2 definitions for parallel terms, but with a cut-
off date modified to reflect this rule. Only ``new California
dischargers'' are required to comply immediately upon commencement of
discharge with effluent limitations derived from the criteria in this
rule. For ``existing dischargers'' whose permits are reissued or
modified to contain new or more stringent limitations based upon
certain water quality requirements, the permit could allow up to five
years, or up to the length of a permit, to comply with such
limitations. The provision applies to new or more stringent effluent
limitations based on the criteria in this EPA rule.
EPA has included ``increasing dischargers'' within the category of
``existing dischargers'' since ``increasing dischargers'' are existing
facilities with a change--an increase--in their discharge. Such
facilities may include those with seasonal variations. ``Increasing
dischargers'' will already have treatment systems in place for their
current discharge, thus, they have less
[[Page 31704]]
opportunity than a new discharger does to design and build a new
treatment system which will meet new water quality-based requirements
for their changed discharge. Allowing existing facilities with an
increasing discharge a compliance schedule will avoid placing the
discharger at a competitive disadvantage vis-a-vis other existing
dischargers who are eligible for compliance schedules.
Today's rule does not prohibit the use of a short-term ``shake down
period'' for new California dischargers as is provided for new sources
or new dischargers in 40 CFR 122.29(d)(4). These regulations require
that the owner or operator of (1) a new source; (2) a new discharger
(as defined in 40 CFR 122.2) which commenced discharge after August 13,
1979; or (3) a recommencing discharger shall install and implement all
pollution control equipment to meet the conditions of the permit before
discharging. The facility must also meet all permit conditions in the
shortest feasible time (not to exceed 90 days). This shake-down period
is not a compliance schedule. This approach may be used to address
violations which may occur during a new facility's start-up, especially
where permit limits are water quality-based and biological treatment is
involved.
The burden of proof to show the necessity of a compliance schedule
is on the discharger, and the discharger must request approval from the
permit issuing authority for a schedule of compliance. The discharger
should submit a description of the minimum required actions or
evaluations that must be undertaken in order to comply with the new or
more restrictive discharge limits. Dates of completion for the required
actions or evaluations should be included, and the proposed schedule
should reflect the shortest practicable time to complete all minimum
required actions.
Duration of Compliance Schedules: Today's rule provides that
compliance schedules may provide for up to five years to meet new or
more stringent effluent limitations in those limited circumstances
where the permittee can demonstrate to the permit authority that an
extended schedule is warranted. EPA's regulations at 122.47 require
compliance with standards as soon as possible. This means that permit
authorities should not allow compliance schedules where the permittee
fails to demonstrate their necessity. This provision should not be
considered a default compliance schedule duration for existing
facilities.
In instances where dischargers wish to conduct toxicological
studies, analyze results, and adopt and implement new or revised water
quality-based effluent limitations, EPA believes that five years is
sufficient time within which to complete this process. See the preamble
to the proposed rule.
Under this rule, where a schedule of compliance exceeds one year,
interim requirements are to be specified and interim progress reports
are to be submitted at least annually to the permit issuing authority,
in at least one-year time intervals.
The rule allows all compliance schedules to extend up to a maximum
duration of five years, which is the maximum term of any NPDES permit.
See 40 CFR 122.46. The discharger's opportunity to obtain a compliance
schedule occurs when the existing permit for that discharge is issued,
reissued or modified to contain more stringent limits based on the
water quality criteria in today's rule. Such compliance schedules,
however, cannot be extended to any indefinite point of time in the
future because the compliance schedule provision in this rule will
sunset on May 18, 2005. The sunset applies to the authorizing provision
in today's rule (40 CFR 131.38(e)), not to individual schedules of
compliance included in specific NPDES permits. Delays in reissuing
expired permits (including those which continue in effect under
applicable NPDES regulations) cannot indefinitely extend the period of
time during which a compliance schedule is in effect. This would occur
where the permit authority includes the single maximum five-year
compliance schedule in a permit that is reissued just before the
compliance schedule provision sunsets (having been previously issued
without WQBELS using the rule's criteria on the eve of the effective
date of this rule). Instead, the effect of the sunset provision is to
limit the longest time period for compliance to ten years after the
effective date of this rule.
EPA recognizes that where a permit is modified during the permit
term, and the permittee needs the full five years to comply, the five-
year schedule may extend beyond the term of the modified permit. In
such cases, the rule allows for the modified permit to contain a
compliance schedule with an interim limit by the end of the permit
term. When the permit is reissued, the permit authority may extend the
compliance schedule in the next permit, provided that, taking into
account the amount of time allowed under the previous permit, the
entire compliance schedule contained in the permit shall not exceed
five years. Final permit limits and compliance dates will be included
in the record for the permit. Final compliance dates must occur within
five years from the date of permit issuance, reissuance, or
modification, unless additional or less time is provided for by law.
EPA would prefer that the State adopt an authorizing compliance
schedule provision but recognizes that the State may not be able to
complete this action for some time after promulgation of the CTR. Thus,
EPA has chosen to promulgate the rule with a sunset provision which
states that the authorizing compliance schedule provision will cease or
sunset on May 18, 2005. However, if the State Board adopts, and EPA
approves, a statewide authorizing compliance schedule provision
significantly prior to May 18, 2005, EPA will act to stay the
authorizing compliance schedule provision in today's rule.
Additionally, if a Regional Board adopts, and the State Board adopts
and EPA approves, a Regional Board authorizing compliance schedule
provision, EPA will act to stay today's provision for the appropriate
or corresponding geographic region in California. At that time, the
State Board's or Regional Board's authorizing compliance schedule
provision will govern the ability of the State regulatory entity to
allow a discharger to include a compliance schedule in a discharger's
NPDES permit.
Antibacksliding: EPA wishes to address the potential concern over
antibacksliding where revised permit limits based on new information
are the result of the completion of additional studies. The Agency's
interpretation of the CWA is that the antibacksliding requirements of
section 402(o) of the CWA do not apply to revisions to effluent
limitations made before the scheduled date of compliance for those
limitations.
State Compliance Schedule Provisions: EPA supports the State in
adopting a statewide provision independent of or as part of the effort
to readopt statewide water quality control plans, or in adopting
individual basin-wide compliance schedule provisions through its nine
Regional Water Quality Control Boards (RWQCBs). The State and RWQCBs
have broad discretion to adopt a provision, including discretion on
reasonable lengths of time for final compliance with WQBELs. EPA
recognizes that practical time frames within which to set interim goals
may be necessary to achieve meaningful, long-term improvements in water
quality in California.
At this time, two RWQCBs have adopted an authorizing compliance
schedule provision as an amendment to
[[Page 31705]]
their respective Basin Plans during the Boards' last triennial review
process. The Basin Plans have been adopted by the State and have come
to EPA for approval. Thus, the Basin Plans' provisions are effective
for the respective Basins. If and when EPA approves of either Regional
Basin Plan, EPA will expeditiously act to amend the CTR, staying its
compliance schedule provision, for the appropriate geographic region.
6. Changes From Proposed Rule
A few changes were made in the final rule from the proposal both as
a result of the Agency's consideration of issues raised in public
comments and Endangered Species Act consultation with the U.S. Fish and
Wildlife Service (FWS) and U.S. National Marine Fisheries Service
(NMFS). The important changes include: reserving the mercury aquatic
life criteria; reserving the selenium freshwater acute aquatic life
criterion; reserving the chloroform human health criteria; and adding a
sunset provision to the authorizing compliance schedule provision. EPA
also clarified that the CTR will not replace priority toxic pollutant
criteria which were adopted by the San Francisco Regional Water Quality
Control Board in its 1986 Basin Plan, adopted by the State Board, and
approved by EPA; specifying the harmonic mean for human health criteria
for non-carcinogens and adding a provision which explicitly allows the
State to adopt and implement an alternative averaging period,
frequency, and design flow for a criterion after opportunity for public
comment.
The first two changes, the reservation of mercury criteria and
selenium criterion, are discussed in more detail below in Section L.,
The Endangered Species Act (ESA). The selenium criterion is also
discussed in more detail above in Section E., Derivation of Criteria,
in subsection 2.b., Freshwater Acute Selenium Criterion. EPA has also
decided to reserve a decision on numeric criteria for chloroform and
therefore not promulgate chloroform criteria in the final rule. As part
of a large-scale regulation promulgated in December l998 under the Safe
Drinking Water Act, EPA published a health-based goal for chloroform
(the maximum contaminant level goal or MCLG) of zero, see 63 FR 69390,
Dec. 16, 1998. EPA provided new data and analyses concerning chloroform
for public review and comment, including a different, mode of action
approach for estimating the cancer risk, 63 FR 15674, March 31, 1998,
but did not reach a conclusion on how to use that new information in
establishing the final MCLG, pending further review by the Science
Advisory Board. EPA has now concluded that any further actions on water
quality criteria should take into account the new data and analysis as
reviewed by the SAB. This decision is consistent with a recent federal
court decision vacating the MCLG for chloroform (Chlorine Chemistry
Council v. EPA, No. 98-1627 (DC Cir., Mar. 31,2000)). EPA intends to
reassess the human health 304(a) criteria recommendation for
chloroform. For these reasons, EPA has decided to reserve a decision on
numeric criteria for chloroform in the CTR and not promulgate water
quality criteria as proposed. Permitting authorities in California
should continue to rely on existing narrative criteria to establish
effluent limitations as necessary for chloroform.
The sunset provision for the authorizing compliance schedule
provision has been added to ease the transition from a Federal
provision to the State's provision that was adopted in March 2000 as
part of its' new statewide implementation plan. The sunset provision is
discussed in more detail in Section G.5 of today's preamble. The CTR
matrix at 40 CFR 131.38(b)(1) makes it explicit that the rule does not
supplant priority toxic pollutant criteria which were adopted by the
San Francisco Regional Water Quality Control Board in its 1986 Basin
Plan, adopted by the State Board, and approved by EPA. This change is
discussed more fully in Section D.4. of today's preamble. EPA modified
the design flow for implementing human health criteria for non-
carcinogens from a 30Q5 to a harmonic mean. Human health criteria for
non-carcinogens are based on an RfD, which is an acceptable daily
exposure over a lifetime. EPA matched the criteria for protection over
a human lifetime with the longest stream flow averaging period, i.e.,
the harmonic mean. Lastly, the CTR now contains language which is
intended to make it easier for the State to adopt and implement an
alternative averaging period, frequency and related design flow, for
situations where the default parameters are inappropriate. This
language is found at 40 CFR 131.38(c)(2)(iv).
H. Economic Analysis
This final rule establishes ambient water quality criteria which,
by themselves, do not directly impose economic impacts (see section K).
These criteria combined with the State-adopted designated uses for
inland surface waters, enclosed bays and estuaries, and implementation
policies, will establish water quality standards. Until the State
implements these water quality standards, there will be no effect of
this rule on any entity. The State will implement these criteria by
ensuring that NPDES permits result in discharges that will meet these
criteria. In so doing, the State will have considerable discretion.
EPA has analyzed the indirect potential costs and benefits of this
rule. In order to estimate the indirect costs and benefits of the rule,
an appropriate baseline must be established. The baseline is the
starting point for measuring incremental costs and benefits of a
regulation. The baseline is established by assessing what would occur
in the absence of the regulation. At present, State Basin Plans contain
a narrative water quality criterion stating that all waters shall be
maintained free of toxic substances in concentrations that produce
detrimental physiological responses in human, plant, animal, or aquatic
life. EPA's regulation at 40 CFR 122.44(d)(1)(vi) requires that where a
discharge causes or has the reasonable potential to cause an excursion
above a narrative criterion within a State water quality standard, the
permitting authority must establish effluent limits but may determine
limits using a number of options. These options include establishing
``effluent limits on a case-by-case basis, using EPA's water quality
criteria published under section 304(a) of the CWA, supplemented where
necessary by other relevant information'' (40 CFR 122.44(d)(1)(vi)(B)).
Thus, to the extent that the State is implementing its narrative
criteria by applying the CWA section 304(a) criteria, this rule does
not impose any incremental costs because the criteria in this rule are
identical to the CWA section 304(a) criteria. Alternatively, to the
extent that the State is implementing its narrative criteria on a
``case-by-case basis'' using ``other relevant information'' in its
permits this rule may impose incremental indirect costs because the
criteria in these permits may not be based on CWA 304(a) criteria. Both
of these approaches to establishing effluent limits are in full
compliance with the CWA.
Because a specific basis for effluent limits in all existing
permits in California is not known, it is not possible to determine a
precise estimate of the indirect costs of this rule. The incremental
costs of the rule may be as low as zero, or as high as $61 million. The
high estimate of costs is based on the possibility that most of the
effluent limits now in effect are not based on 304(a) criteria. EPA
evaluated these
[[Page 31706]]
indirect costs using two different approaches. The first approach uses
existing discharge data and makes assumptions about future State NPDES
permit limits. Actual discharge levels are usually lower than the level
set by current NPDES permit limits. This approach, representing the
low-end scenario, also assumes that some of the discretionary
mechanisms that would enhance flexibility (e.g., site specific
criteria, mixing zones) would be granted by the State. The second
approach uses a sample of existing permit limits and assumes that
dischargers are actually discharging at the levels contained in their
permits and makes assumptions about limits statewide that would be
required under the rule. This approach, representing the high-end
scenario, also assumes that none of the discretionary mechanisms that
would enhance flexibility (e.g., site specific criteria, mixing zones)
would be granted by the State. These two approaches recognize that the
State has significant flexibility and discretion in how it chooses to
implement standards within the NPDES permit program, the EA by
necessity includes many assumptions about how the State will implement
the water quality standards. These assumptions are based on a
combination of EPA guidance and current permit conditions for the
facilities examined in this analysis. To account for the uncertainty of
EPA's implementation assumptions, this analysis estimates a wide range
of costs and benefits. By completing the EA, EPA intends to inform the
public about how entities might be potentially affected by State
implementation of water quality standards in the NPDES permit program.
The costs and benefits sections that follow summarize the methodology
and results of the analysis.
1. Costs
EPA assessed the potential compliance costs that facilities may
incur to meet permit limits based on the criteria in today's rule. The
analysis focused on direct compliance costs such as capital costs and
operation and maintenance costs (O&M) for end-of-pipe pollution
control, indirect source controls, pollution prevention, monitoring,
and costs of pursuing alternative methods of compliance.
The population of facilities with NPDES permits that discharge into
California's enclosed bays, estuaries and inland surface waters
includes 184 major dischargers and 1,057 minor dischargers. Of the 184
major facilities, 128 are publicly owned treatment works (POTWs) and 56
are industrial facilities. Approximately 2,144 indirect dischargers
designated as significant industrial users discharge wastewater to
those POTWs. In the EA for the proposed CTR, EPA used a three-phased
process to select a sample of facilities to represent California
dischargers potentially affected by the State's implementation of
permit limits based on the criteria contained in this rule.
The first phase consisted of choosing three case study areas for
which data was thought to exist. The three case studies with a total of
5 facilities included: the South San Francisco Bay (the San Jose/Santa
Clara Water Pollution Control Plant and Sunnyvale Water Pollution
Control Plant); the Sacramento River (the Sacramento Regional
Wastewater Treatment Plant); and the Santa Ana River (the City of
Riverside Water Quality Control Plant and the City of Colton Municipal
Wastewater Treatment Facility). The second phase consisted of selecting
five additional major industrial dischargers to complement the case-
study POTWs.
The third phase involved selecting 10 additional facilities to
improve the basis for extrapolating the costs of the selected sample
facilities to the entire population of potentially affected
dischargers. The additional 10 facilities were selected such that the
group examined: (1) Was divided between major POTWs and major
industrial discharger categories in proportion to the numbers of
facilities in the State; (2) gave greater proportionate representation
to major facilities than minor facilities based on a presumption that
the majority of compliance costs would be incurred by major facilities;
(3) gave a proportionate representation to each of four principal
conventional treatment processes typically used by facilities in
specified industries in California; and (4) was representative of the
proportionate facilities located within the different California
Regional Water Quality Control Boards. Within these constraints,
facilities were selected at random to complete the sample.
In the EA for today's final rule, EPA primarily used the same
sample as the EA for the proposed rule with some modifications. EPA
increased the number of minor POTWs and minor industrial facilities in
the sample. EPA randomly selected four new minor POTW facilities and
five new minor industrial facilities to add to the sample. The number
of sample facilities selected in each area under the jurisdiction of a
Regional Water Quality Control Board was roughly proportional to the
universe of facilities in each area.
For those facilities that were projected to exceed permit limits
based on the criteria, EPA estimated the incremental costs of
compliance. Using a decision matrix or flow chart, costs were developed
for two different scenarios--a ``low-end'' cost scenario and a ``high-
end'' cost scenario--to account for a range of regulatory flexibility
available to the State when implementing permit limits based on the
water quality criteria. The assumptions for baseline loadings also vary
over the two scenarios. The low-end scenario generally assumed that
facilities were discharging at the maximum effluent concentrations
taken from actual monitoring data, while the high-end scenario
generally assumed that facilities were discharging at their current
effluent limits. The decision matrix specified assumptions used for
selection of control options, such as optimization of existing
treatment processes and operations, in-plant pollutant minimization and
prevention, and end-of-pipe treatment.
The annualized potential costs that direct and indirect dischargers
may incur as a result of State implementation of permit limits based on
water quality standards using today's criteria are estimated to be
between $33.5 million and $61 million. EPA believes that the costs
incurred as a result of State implementation of these permit limits
will approach the low-end of the cost range. Costs are unlikely to
reach the high-end of the range because State authorities are likely to
choose implementation options that provide some degree of flexibility
or relief to point source dischargers. Furthermore, cost estimates for
both scenarios, but especially for the high-end scenario, may be
overstated because the analysis tended to use conservative assumptions
in calculating these permit limits and in establishing baseline
loadings. The baseline loadings for the high-end were based on current
effluent limits rather than actual pollutant discharge data. Most
facilities discharge pollutants in concentrations well below current
effluent limits. In addition, both the high-end and low-end cost
estimates in the EA may be slightly overstated since potential costs
incurred to reduce chloroform discharges were included in these
estimates. EPA made a decision to reserve the chloroform human health
criteria after the EA was completed.
Under the low-end cost scenario, major industrial facilities and
POTWs would incur about 27 percent of the potential costs, indirect
dischargers would incur about 70 percent of the potential costs, while
minor dischargers would incur about 3 percent. Of the major direct
dischargers, POTWs would incur the largest share of projected costs (87
percent). However, distributed
[[Page 31707]]
among 128 major POTWs in the State, the average cost per plant would be
$61,000 per year. Chemical and petroleum industries would incur the
highest cost of the industrial categories (5.6 percent of the annual
costs, with an annual average of $25,200 per plant). About 57 percent
of the low-end costs would be associated with pollution prevention
activities, while nearly 38 percent would be associated with pursuing
alternative methods of compliance under the regulations.
Under the high-end cost scenario, major industrial facilities and
POTWs would incur about 94 percent of the potential costs, indirect
dischargers would incur about 17 percent of the potential costs, while
minor dischargers would incur about 5 percent. Among the major, direct
dischargers, two categories would incur the majority of potential
costs--major POTWs (82 percent), Chemical/Petroleum Products (9
percent). The average annual per plant cost for different industry
categories would ranges from zero to $324,000. The two highest average
cost categories would be major POTWs ($324,000 per year) and Chemical/
Petroleum Products ($221,264 per year). The shift in proportion of
potential costs between direct and indirect dischargers is due to the
assumption that more direct dischargers would use end-of-pipe treatment
under the high-end scenario. Thus, a smaller proportion of indirect
dischargers would be impacted under the high-end scenario, since some
municipalities are projected to add end-of-pipe treatment which would
reduce the need for controls from indirect discharges. Over 91 percent
of the annual costs are for waste minimization and treatment
optimization costs. Waste minimization would represent nearly 84% of
the total annual costs. Capital and operation and maintenance costs
would make up less than 9 percent of annual costs.
Cost-Effectiveness: Cost-effectiveness is estimated in terms of the
cost of reducing the loadings of toxic pollutants from point sources.
The cost-effectiveness is derived by dividing the projected annual
costs of implementing permit limits based on water quality standards
using today's criteria by the toxicity-weighted pounds (pound-
equivalents) of pollutants removed. Pound-equivalents are calculated by
multiplying pounds of each pollutant removed by the toxic weight (based
on the toxicity of copper) for that pollutant.
Based on this analysis, State implementation of permit limits based
on today's criteria would be responsible for the reduction of about 1.1
million to 2.7 million toxic pound-equivalents per year, or 15 to 50
percent of the toxic-weighted baseline loadings for the high-and low-
end scenarios, respectively. The cost-effectiveness of the scenarios
would range from $22 (high-end scenario) to $31 (low-end scenario) per
pound-equivalent.
2. Benefits
The benefits analysis is intended to provide insight into both the
types and potential magnitude of the economic benefits expected as a
result of implementation of water quality standards based on today's
criteria. To the extent feasible, empirical estimates of the potential
magnitude of the benefits were developed and then compared to the
estimated costs of implementing water quality standards based on
today's criteria.
To perform a benefits analysis, the types or categories of benefits
that apply need to be defined. EPA relied on a set of benefits
categories that typically apply to changes in the water resource
environment. Benefits were categorized as either use benefits or
passive (nonuse) benefits depending on whether or not they involve
direct use of, or contact with, the resource. The most prominent use
benefit categories are those related to recreational fishing, boating,
and swimming. Another use benefit category of significance is human
health risk reduction. Human health risk reductions can be realized
through actions that reduce human exposure to contaminants such as
exposure through the consumption of fish containing elevated levels of
pollutants. Passive use benefits are those improvements in
environmental quality that are valued by individuals apart from any use
of the resource in question.
Benefits estimates were derived in this study using an approach in
which benefits of discrete large-scale changes in water quality beyond
present day conditions were estimated wherever feasible. A share of
those benefits was then apportioned to implementation of water quality
standards based on today's criteria. The apportionment estimate was
based on a three-stage process:
First, EPA assessed current total loadings from all sources that
are contributing to the toxics-related water quality problems observed
in the State. This defines the overall magnitude of loadings. Second,
the share of total loadings that are attributable to sources that would
be controlled through implementation of water quality standards based
on today's criteria was estimated. Since this analysis was designed to
focus only on those controls imposed on point sources, this stage of
the process entailed estimating the portion of total loadings
originating from point sources. Third, the percentage reduction in
loadings expected due to implementation of today's criteria was
estimated and then multiplied by the share of point source loadings to
calculate the portion of benefits that could be attributed to
implementation of water quality standards based on today's criteria.
Total monetized annual benefits were estimated in the range of $6.9
to $74.7 million. By category, annual benefits would be $1.3 to $4.6
million for avoided cancer risk, $2.2 to $15.2 million for recreational
angling, and $3.4 to $54.9 million for passive use benefits.
There are numerous categories of potential or likely benefits that
have been omitted from the quantified and monetized benefit estimates.
In terms of potential magnitudes of benefit, the following are likely
to be significant contributors to the underestimation of the monetized
values presented above:
Improvements in water-related (in-stream and near stream)
recreation apart from fishing. The omission of potential motorized and
nonmotorized boating, swimming, picnicking, and related in-stream and
stream-side recreational activities from the benefits estimates could
contribute to an appreciable underestimation of total benefits. Such
recreational activities have been shown in empirical research to be
highly valued, and even modest changes in participation and or user
values could lead to sizable benefits statewide. Some of these
activities can be closely associated with water quality attributes
(notably, swimming). Other recreational activities may be less directly
related to the water quality improvements, but might nonetheless
increase due to their association with fishing, swimming, or other
activities in which the participants might engage.
Improvements in consumptive and nonconsumptive land-based
recreation, such as hunting and wildlife observation. Improvements in
aquatic habitats may lead (via food chain and related ecologic benefit
mechanisms) to healthier, larger, and more diverse populations of avian
and terrestrial species, such as waterfowl, eagles, and otters.
Improvements in the populations for these species could manifest as
improved hunting and wildlife viewing opportunities, which might in
turn increase participation and user day values for such activities.
Although the scope of the benefits analysis has not allowed a
quantitative assessment of these values at either pre- or post-rule
[[Page 31708]]
conditions, it is conceivable that these benefits could be appreciable.
Improvements in human health resulting from reduction of
non-cancer risk. EPA estimated that implementation of water quality
standards based on the criteria would result in a reduction of mercury
concentrations in fish tissue and, thus, a reduction in the hazard from
consumption of mercury contaminated fish. However, EPA was unable to
monetize benefits due to reduced non-cancer health effects.
Human health benefits for saltwater anglers outside of San
Francisco Bay were not estimated. The number of saltwater anglers
outside of San Francisco Bay is estimated to be 673,000 (based on
Huppert, 1989, and U.S. FWS, 1993). The omission of other saltwater
anglers may cause human health benefits to be underestimated. In
addition, benefit estimates in the EA may be slightly overstated since
potential benefits from reductions in chloroform discharges were
included in these estimates. EPA made a decision to reserve the
chloroform human health criteria after the EA was completed.
EPA received a number of comments which requested the Agency use
the cost-benefit analysis in the EA as a factor in setting water
quality criteria. EPA does not use the EA as a basis in determining
protective water quality criteria. EPA's current regulations at 40 CFR
131.11 state that the criteria must be based on sound scientific
rationale and must protect the designated use. From the outset of the
water quality standards program, EPA has explained that while economic
factors may be considered in designating uses, they may not be used to
justify criteria that are not protective of those uses. 44 FR 25223-
226, April 30, 1979. See e.g. Mississippi Commission on Natural
Resources v. Costle, 625 F. 2d 1269, 1277 (5th Cir. 1980). EPA
reiterated this interpretation of the CWA and its implementing
regulations in discussing section 304(a) recommended criteria guidance
stating that ``they are based solely on data and scientific judgments
on the relationship between pollutant concentrations and environmental
and human health effects and do not reflect consideration of economic
impacts or the technological feasibility of meeting the chemical
concentrations in ambient water.'' 63 FR 36742 and 36762, July 7, 1998.
I. Executive Order 12866, Regulatory Planning and Review
Under Executive Order 12866 (58 FR 51735, October 4, 1993), the
Agency must determine whether the regulatory action is ``significant''
and therefore subject to Office of Management and Budget (OMB) review
and the requirements of the Executive Order. The Order defines
``significant regulatory action'' as one that is likely to result in a
rule that may:
(1) Have an annual effect on the economy of $100 million or more or
adversely affect in a material way the economy, a sector of the
economy, productivity, competition, jobs, the environment, public
health or safety, or State, local, or tribal governments or
communities;
(2) Create a serious inconsistency or otherwise interfere with an
action taken or planned by another Agency;
(3) Materially alter the budgetary impact of entitlements, grants,
user fees, or loan programs or the rights and obligations of recipients
thereof; or
(4) Raise novel legal or policy issues arising out of legal
mandates, the President's priorities, or the principles set forth in
the Executive Order.
It has been determined that this rule is not a ``significant
regulatory action'' under the terms of Executive Order 12866 and is
therefore not subject to OMB review.
J. Unfunded Mandates Reform Act of 1995
Title II of the Unfunded Mandates Reform Act of 1995 (UMRA), Public
Law 104-4, establishes requirements for Federal agencies to assess the
effects of their regulatory actions on State, local, and tribal
governments and the private sector. Under section 202 of the UMRA, EPA
generally must prepare a written statement, including a cost-benefit
analysis, for proposed and final rules with ``Federal mandates'' that
may result in expenditures to State, local, and tribal governments, in
the aggregate, or to the private sector, of $100 million or more in any
one year. Before promulgating any regulation for which a written
statement is needed, section 205 of the UMRA generally requires EPA to
identify and consider a reasonable number of regulatory alternatives
and adopt the least costly, most cost-effective or least burdensome
alternative that achieves the objectives of the rule. The provisions of
section 205 do not apply when they are inconsistent with applicable
law. Moreover, section 205 allows an Agency to adopt an alternative
other than the least costly, most cost-effective or least burdensome
alternative if the Administrator publishes with the final rule an
explanation why that alternative was not adopted. Before EPA
establishes any regulatory requirements that may significantly or
uniquely affect small governments, including tribal governments, it
must have developed under section 203 of the UMRA a small government
Agency plan. The plan must provide for notifying potentially affected
small governments, enabling officials of the affected small governments
to have meaningful and timely input in the development of regulatory
proposals with significant Federal intergovernmental mandates, and EPA
informing, educating, and advising small governments on compliance with
the regulatory requirements.
Today's rule contains no Federal mandates (under the regulatory
provisions of Title II of the Unfunded Mandates Reform Act (UMRA)) for
State, local, or tribal governments or the private sector. Today's rule
imposes no enforceable duty on any State, local or Tribal governments
or the private sector; rather, the CTR promulgates ambient water
quality criteria which, when combined with State-adopted uses, will
create water quality standards for those water bodies with adopted
uses. The State will then use these resulting water quality standards
in implementing its existing water quality control programs. Thus,
today's rule is not subject to the requirements of sections 202 and 205
of the UMRA.
EPA has determined that this rule contains no regulatory
requirements that might significantly or uniquely affect small
governments. This rule establishes ambient water quality criteria
which, by themselves do not directly impact any entity. The State will
implement these criteria by ensuring that NPDES permits result in
discharges that will meet these criteria. In so doing, the State will
have considerable discretion. Until the State implements these water
quality standards, there will be no effect of this rule on any entity.
Thus, today's rule is not subject to the requirements of section 203 of
UMRA.
K. Regulatory Flexibility Act
The Regulatory Flexibility Act generally requires Federal agencies
to prepare a regulatory flexibility analysis of any rule subject to
notice and comment rulemaking requirements under the Administrative
Procedure Act or any other statute unless the Agency certifies that the
rule will not have a significant economic impact of a substantial
number of small entities. Small entities include small businesses,
small organizations, and small governmental jurisdictions. For purposes
of assessing the impacts of today's rule on small entities, small
entity is defined as: (1) A small business according to RFA default
definitions for small businesses (based on SBA size
[[Page 31709]]
standards); (2) a small governmental jurisdiction that is a government
of a city, county, town, school district or special district with a
population of less than 50,000; and (3) a small organization that is
any not-for-profit enterprise which is independently owned and operated
and is not dominant in its field.
After considering the economic impacts of today's final rule on
small entities, I certify that this action will not have a significant
economic impact on a substantial number of small entities. This final
rule will not impose any requirements on small entities.
Under the CWA water quality standards program, States must adopt
water quality standards for their waters that must be submitted to EPA
for approval. If the Agency disapproves a State standard and the State
does not adopt appropriate revisions to address EPA's disapproval, EPA
must promulgate standards consistent with the statutory requirements.
EPA has authority to promulgate criteria or standards in any case where
the Administrator determines that a revised or new standard is
necessary to meet the requirements of the Act. These State standards
(or EPA-promulgated standards) are implemented through various water
quality control programs including the National Pollutant Discharge
Elimination System (NPDES) program that limits discharges to navigable
waters except in compliance with an EPA permit or permit issued under
an approved State NPDES program. The CWA requires that all NPDES
permits must include any limits on discharges that are necessary to
meet State water quality standards.
Thus, under the CWA, EPA's promulgation of water quality criteria
or standards establishes standards that the State, in turn, implements
through the NPDES permit process. The State has considerable discretion
in deciding how to meet the water quality standards and in developing
discharge limits as needed to meet the standards. In circumstances
where there is more than one discharger to a water body that is subject
to water quality standards or criteria, a State also has discretion in
deciding on the appropriate limits for the different dischargers. While
the State's implementation of federally-promulgated water quality
criteria or standards may result indirectly in new or revised discharge
limits for small entities, the criteria or standards themselves do not
apply to any discharger, including small entities.
Today's rule, as explained above, does not itself establish any
requirements that are applicable to small entities. As a result of
EPA's action here, the State of California will need to ensure that
permits it issues include limits as necessary to meet the water quality
standards established by the criteria in today's rule. In so doing, the
State will have a number of discretionary choices associated with
permit writing. While California's implementation of today's rule may
ultimately result in some new or revised permit conditions for some
dischargers, including small entities, EPA's action today does not
impose any of these as yet unknown requirements on small entities.
The RFA requires analysis of the economic impact of a rule only on
the small entities subject to the rule's requirements. Courts have
consistently held that the RFA imposes no obligation on an Agency to
prepare a small entity analysis of the effect of a rule on entities not
regulated by the rule. Motor & Equip. Mrfrs. Ass'n v. Nichols, 142 F.3d
449, 467 & n.18 (D.C. Cir. 1998)(quoting United States Distribution
Companies v. FERC, 88 F.3d 1105, 1170 (D.C. Cir. 1996); see also
American Trucking Association, Inc. v. EPA, 175 F.3d 1027 (D.C. Cir.
1999). This final rule will have a direct effect only on the State of
California which is not a small entity under the RFA. Thus, individual
dischargers, including small entities, are not directly subject to the
requirements of the rule. Moreover, because of California's discretion
in implementing these standards, EPA cannot assess the extent to which
the promulgation of this rule may subsequently affect any dischargers,
including small entities. Consequently, certification under section
605(b) is appropriate. State of Michigan, et al. v. U.S. Environmental
Protection Agency, No. 98-1497 (D.C. Cir. Mar. 3, 2000), slip op. at
41-42.
L. Paperwork Reduction Act
This action requires no new or additional information collection,
reporting, or record keeping subject to the Paperwork Reduction Act, 44
U.S.C. 3501 et seq.
M. Endangered Species Act
Pursuant to section 7(a) of the Endangered Species Act (ESA), EPA
has consulted with the U.S. Fish and Wildlife Service and the U.S.
National Marine Fisheries Service (collectively, the Services)
concerning EPA's rulemaking action for the State of California. EPA
initiated informal consultation in early 1994, and completed formal
consultation in April 2000. As a result of the consultation, EPA
modified some of the provisions in the final rule.
As part of the consultation process, EPA submitted to the Services
a Biological Evaluation for their review in October of 1997. This
evaluation found that the proposed CTR was not likely to jeopardize the
continued existence of any Federally listed species or result in the
destruction or adverse modification of designated critical habitat. In
April of 1998, the Services sent EPA a draft Biological Opinion which
tentatively found that EPA's proposed rule would jeopardize the
continued existence of several Federally listed species and result in
the destruction or have adverse effect on designated critical habitat.
After lengthy discussions with the Services, EPA agreed to several
changes in the final rule and the Services in turn issued a final
Biological Opinion finding that EPA's action would not likely
jeopardize the continued existence of any Federally listed species or
result in the destruction or adverse modification of designated
critical habitat. EPA's Biological Evaluation and the Services' final
Biological Opinion are contained in the administrative record for
today's rule.
In order to ensure the continued protection of Federally listed
threatened and endangered species and to protect their critical
habitat, EPA agreed to reserve the aquatic life criteria for mercury
and the acute freshwater aquatic life criterion for selenium. The
Services believe that EPA's proposed criteria are not sufficiently
protective of Federally listed species and should not be promulgated.
EPA agreed that it would reevaluate these criteria in light of the
Services concerns before promulgating them for the State of California.
Other commitments made by EPA are described in a letter to the Services
dated December 16, 1999; this letter is contained in the administrative
record for today's rule.
N. Congressional Review Act
The Congressional Review Act, 5 U.S.C. 801 et seq., as added by the
Small Business Regulatory Enforcement Fairness Act of 1996, generally
provides that before a rule may take effect, the Agency promulgating
the rule must submit a rule report, which includes a copy of the rule,
to each House of the Congress and to the Comptroller General of the
United States. EPA will submit a report containing this rule and other
required information to the U.S. Senate, the U.S. House of
Representatives, and the Comptroller General of the United States prior
to publication of the rule in the Federal Register. A major rule cannot
take effect until 60 days after it is published in the Federal
Register. This rule is not a major rule as defined
[[Page 31710]]
by 5 U.S.C. 804(2). This rule will be effective May 18, 2000.
O. Executive Order 13084, Consultation and Coordination With Indian
Tribal Governments
Under Executive Order 13084, EPA may not issue a regulation that is
not required by statute, that significantly or uniquely affects the
communities of Indian tribal governments, and that imposes substantial
direct compliance costs on those communities, unless the Federal
government provides the funds necessary to pay the direct compliance
costs incurred by the tribal governments, or EPA consults with those
governments. If EPA complies by consulting, Executive Order 13084
requires EPA to provide to the Office of Management and Budget, in a
separately identified section of the preamble to the rule, a
description of the extent of EPA's prior consultation with
representatives of affected tribal governments, a summary of the nature
of their concerns, and a statement supporting the need to issue the
regulation. In addition, Executive Order 13084 requires EPA to develop
an effective process permitting elected officials and other
representatives of Indian tribal governments ``to provide meaningful
and timely input in the development of regulatory policies on matters
that significantly or uniquely affect their communities.''
Today's rule does not significantly or uniquely affect the
communities of Indian tribal governments nor does it impose substantial
direct compliance cots on them. Today's rule will only address priority
toxic pollutant water quality criteria for the State of California and
does not apply to waters in Indian country. Accordingly, the
requirements of section 3(b) of Executive Order 13084 do not apply to
this rule.
P. National Technology Transfer and Advancement Act
Section 12(d) of the National Technology Transfer and Advancement
Act of 1995 (``NTTAA''), Public Law No. 104-113, section 12(d) (15
U.S.C. 272 note) directs EPA to use voluntary consensus standards in
its regulatory activities unless to do so would be inconsistent with
applicable law or otherwise impractical. Voluntary consensus standards
are technical standards (e.g., materials specifications, test methods,
sampling procedures, and business practices) that are developed or
adopted by voluntary consensus standards bodies. The NTTAA directs EPA
to provide Congress, through OMB, explanations when the Agency decides
not to use available and applicable voluntary consensus standards.
This final rule does not involve technical standards. Therefore,
EPA did not consider the use of any voluntary consensus standards.
Q. Executive Order 13132 on Federalism
Executive Order 13132, entitled ``Federalism'' (64 FR 43255, August
10, 1999), requires EPA to develop an accountable process to ensure
``meaningful and timely input by State and local officials in the
development of regulatory policies that have federalism implications.''
``Policies that have federalism implications'' is defined in the
Executive Order to include regulations that have ``substantial direct
effects on the States, on the relationship between the national
government and the States, or on the distribution of power and
responsibilities among the various levels of government.''
Under section 6 of Executive Order 13132, EPA may not issue a
regulation that has federalism implications, that imposes substantial
direct compliance costs, and that is not required by statute, unless
the Federal government provides the funds necessary to pay the direct
compliance costs incurred by State and local governments, or EPA
consults with State and local officials early in the process of
developing the proposed regulation. EPA also may not issue a regulation
that has federalism implications and that preempts State law, unless
the Agency consults with State and local officials early in the process
of developing the proposed regulation.
This final rule does not have federalism implications. It will not
have substantial direct effects on the States, on the relationship
between the national government and the States, or on the distribution
of power and responsibilities among the various levels of government,
as specified in Executive Order 13132. The rule does not affect the
nature of the relationship between EPA and States generally, for the
rule only applies to water bodies in California. Further, the rule will
not substantially affect the relationship of EPA and the State of
California, or the distribution of power or responsibilities between
EPA and the State. The rule does not alter the State's authority to
issue NPDES permits or the State's considerable discretion in
implementing these criteria. The rule simply implements Clean Water Act
section 303(c)(2)(B) requiring numeric ambient water quality criteria
for which EPA has issued section 304(a) recommended criteria in a
manner that is consistent with previous regulatory guidance that the
Agency has issued to implement CWA section 303(c)(2)(B). Further, this
rule does not preclude the State from adopting water quality standards
that meet the requirements of the CWA. Thus, the requirements of
section 6 of the Executive Order do not apply to this rule.
Although section 6 of Executive Order 13132 does not apply to this
rule, EPA did consult with State and local government representatives
in developing this rule. EPA and the State reached an agreement that to
best utilize its respective resources, EPA would promulgate water
quality criteria and the State would concurrently work on a plan to
implement the criteria. Since the proposal of this rule, EPA has kept
State officials fully informed of changes to the proposal. EPA has
continued to invite comment from the State on these changes. EPA
believes that the final CTR incorporates comments from State officials
and staff.
R. Executive Order 13045 on Protection of Children From
Environmental Health Risks and Safety Risks
Executive Order 13045: ``Protection of Children from Environmental
Health Risks and Safety Risks'' (62 FR 19885, April 23, 1997) applies
to any rule that: (1) Is determined to be ``economically significant''
as defined under Executive Order 12866, and (2) concerns an
environmental health or safety risk that EPA has reason to believe may
have a disproportionate effect on children. If the regulatory action
meets both criteria, the Agency must evaluate the environmental health
or safety effects of the planned rule on children, and explain why the
planned regulation is preferable to other potentially effective and
reasonably feasible alternatives considered by the Agency.
While this final rule is not subject to the Executive Order because
it is not economically significant as defined in Executive Order 12866,
we nonetheless have reason to believe that the environmental health or
safety risk addressed by this action may have a disproportionate effect
on children. As a matter of EPA policy, we therefore have assessed the
environmental health or safety effects of ambient water quality
criteria on children. The results of this assessment are contained in
section F.3., Human Health Criteria.
List of Subjects in 40 CFR Part 131
Environmental protection, Indians--lands, Intergovernmental
relations, Reporting and recordkeeping requirements, Water pollution
control.
[[Page 31711]]
Dated: April 27, 2000.
Carol Browner,
Administrator.
For the reasons set out in the preamble, part 131 of chapter I of
title 40 of the Code of Federal Regulations is amended as follows:
PART 131--WATER QUALITY STANDARDS
1. The authority citation for part 131 continues to read as
follows:
Authority: 33 U.S.C. 1251 et seq.
Subpart D--[Amended]
2. Section 131.38 is added to subpart D to read as follows:
Sec. 131.38 Establishment of Numeric Criteria for Priority Toxic
Pollutants for the State of California.
(a) Scope. This section promulgates criteria for priority toxic
pollutants in the State of California for inland surface waters and
enclosed bays and estuaries. This section also contains a compliance
schedule provision.
(b)(1) Criteria for Priority Toxic Pollutants in the State of
California as described in the following table:
BILLING CODE 6560-50-P
[[Page 31712]]
[GRAPHIC] [TIFF OMITTED] TR18MY00.007
[[Page 31713]]
[GRAPHIC] [TIFF OMITTED] TR18MY00.008
[[Page 31714]]
[GRAPHIC] [TIFF OMITTED] TR18MY00.009
[[Page 31715]]
[GRAPHIC] [TIFF OMITTED] TR18MY00.010
BILLING CODE 6560-50-C
[[Page 31716]]
Footnotes to Table in Parargraph (b)(1):
a. Criteria revised to reflect the Agency q1* or RfD, as
contained in the Integrated Risk Information System (IRIS) as of
October 1, 1996. The fish tissue bioconcentration factor (BCF) from
the 1980 documents was retained in each case.
b. Criteria apply to California waters except for those waters
subject to objectives in Tables III-2A and III-2B of the San
Francisco Regional Water Quality Control Board's (SFRWQCB) 1986
Basin Plan, that were adopted by the SFRWQCB and the State Water
Resources Control Board, approved by EPA, and which continue to
apply.
c. Criteria are based on carcinogenicity of 10 (-6) risk.
d. Criteria Maximum Concentration (CMC) equals the highest
concentration of a pollutant to which aquatic life can be exposed
for a short period of time without deleterious effects. Criteria
Continuous Concentration (CCC) equals the highest concentration of a
pollutant to which aquatic life can be exposed for an extended
period of time (4 days) without deleterious effects. ug/L equals
micrograms per liter.
e. Freshwater aquatic life criteria for metals are expressed as
a function of total hardness (mg/L) in the water body. The equations
are provided in matrix at paragraph (b)(2) of this section. Values
displayed above in the matrix correspond to a total hardness of 100
mg/l.
f. Freshwater aquatic life criteria for pentachlorophenol are
expressed as a function of pH, and are calculated as follows: Values
displayed above in the matrix correspond to a pH of 7.8. CMC =
exp(1.005(pH)-4.869). CCC = exp(1.005(pH)-5.134).
g. This criterion is based on 304(a) aquatic life criterion
issued in 1980, and was issued in one of the following documents:
Aldrin/Dieldrin (EPA 440/5-80-019), Chlordane (EPA 440/5-80-027),
DDT (EPA 440/5-80-038), Endosulfan (EPA 440/5-80-046), Endrin (EPA
440/5-80-047), Heptachlor (440/5-80-052), Hexachlorocyclohexane (EPA
440/5-80-054), Silver (EPA 440/5-80-071). The Minimum Data
Requirements and derivation procedures were different in the 1980
Guidelines than in the 1985 Guidelines. For example, a ``CMC''
derived using the 1980 Guidelines was derived to be used as an
instantaneous maximum. If assessment is to be done using an
averaging period, the values given should be divided by 2 to obtain
a value that is more comparable to a CMC derived using the 1985
Guidelines.
h. These totals simply sum the criteria in each column. For
aquatic life, there are 23 priority toxic pollutants with some type
of freshwater or saltwater, acute or chronic criteria. For human
health, there are 92 priority toxic pollutants with either ``water +
organism'' or ``organism only'' criteria. Note that these totals
count chromium as one pollutant even though EPA has developed
criteria based on two valence states. In the matrix, EPA has
assigned numbers 5a and 5b to the criteria for chromium to reflect
the fact that the list of 126 priority pollutants includes only a
single listing for chromium.
i. Criteria for these metals are expressed as a function of the
water-effect ratio, WER, as defined in paragraph (c) of this
section. CMC = column B1 or C1 value x WER; CCC = column B2 or C2
value x WER.
j. No criterion for protection of human health from consumption
of aquatic organisms (excluding water) was presented in the 1980
criteria document or in the 1986 Quality Criteria for Water.
Nevertheless, sufficient information was presented in the 1980
document to allow a calculation of a criterion, even though the
results of such a calculation were not shown in the document.
k. The CWA 304(a) criterion for asbestos is the MCL.
l. [Reserved]
m. These freshwater and saltwater criteria for metals are
expressed in terms of the dissolved fraction of the metal in the
water column. Criterion values were calculated by using EPA's Clean
Water Act 304(a) guidance values (described in the total recoverable
fraction) and then applying the conversion factors in
Sec. 131.36(b)(1) and (2).
n. EPA is not promulgating human health criteria for these
contaminants. However, permit authorities should address these
contaminants in NPDES permit actions using the State's existing
narrative criteria for toxics.
o. These criteria were promulgated for specific waters in
California in the National Toxics Rule (``NTR''), at Sec. 131.36.
The specific waters to which the NTR criteria apply include: Waters
of the State defined as bays or estuaries and waters of the State
defined as inland, i.e., all surface waters of the State not ocean
waters. These waters specifically include the San Francisco Bay
upstream to and including Suisun Bay and the Sacramento-San Joaquin
Delta. This section does not apply instead of the NTR for this
criterion.
p. A criterion of 20 ug/l was promulgated for specific waters in
California in the NTR and was promulgated in the total recoverable
form. The specific waters to which the NTR criterion applies
include: Waters of the San Francisco Bay upstream to and including
Suisun Bay and the Sacramento-San Joaquin Delta; and waters of Salt
Slough, Mud Slough (north) and the San Joaquin River, Sack Dam to
the mouth of the Merced River. This section does not apply instead
of the NTR for this criterion. The State of California adopted and
EPA approved a site specific criterion for the San Joaquin River,
mouth of Merced to Vernalis; therefore, this section does not apply
to these waters.
q. This criterion is expressed in the total recoverable form.
This criterion was promulgated for specific waters in California in
the NTR and was promulgated in the total recoverable form. The
specific waters to which the NTR criterion applies include: Waters
of the San Francisco Bay upstream to and including Suisun Bay and
the Sacramento-San Joaquin Delta; and waters of Salt Slough, Mud
Slough (north) and the San Joaquin River, Sack Dam to Vernalis. This
criterion does not apply instead of the NTR for these waters. This
criterion applies to additional waters of the United States in the
State of California pursuant to 40 CFR 131.38(c). The State of
California adopted and EPA approved a site-specific criterion for
the Grassland Water District, San Luis National Wildlife Refuge, and
the Los Banos State Wildlife Refuge; therefore, this criterion does
not apply to these waters.
r. These criteria were promulgated for specific waters in
California in the NTR. The specific waters to which the NTR criteria
apply include: Waters of the State defined as bays or estuaries
including the San Francisco Bay upstream to and including Suisun Bay
and the Sacramento-San Joaquin Delta. This section does not apply
instead of the NTR for these criteria.
s. These criteria were promulgated for specific waters in
California in the NTR. The specific waters to which the NTR criteria
apply include: Waters of the Sacramento-San Joaquin Delta and waters
of the State defined as inland ( i.e., all surface waters of the
State not bays or estuaries or ocean) that include a MUN use
designation. This section does not apply instead of the NTR for
these criteria.
t. These criteria were promulgated for specific waters in
California in the NTR. The specific waters to which the NTR criteria
apply include: Waters of the State defined as bays and estuaries
including San Francisco Bay upstream to and including Suisun Bay and
the Sacramento-San Joaquin Delta; and waters of the State defined as
inland (i.e., all surface waters of the State not bays or estuaries
or ocean) without a MUN use designation. This section does not apply
instead of the NTR for these criteria.
u. PCBs are a class of chemicals which include aroclors 1242,
1254, 1221, 1232, 1248, 1260, and 1016, CAS numbers 53469219,
11097691, 11104282, 11141165, 12672296, 11096825, and 12674112,
respectively. The aquatic life criteria apply to the sum of this set
of seven aroclors.
v. This criterion applies to total PCBs, e.g., the sum of all
congener or isomer or homolog or aroclor analyses.
w. This criterion has been recalculated pursuant to the 1995
Updates: Water Quality Criteria Documents for the Protection of
Aquatic Life in Ambient Water, Office of Water, EPA-820-B-96-001,
September 1996. See also Great Lakes Water Quality Initiative
Criteria Documents for the Protection of Aquatic Life in Ambient
Water, Office of Water, EPA-80-B-95-004, March 1995.
x. The State of California has adopted and EPA has approved site
specific criteria for the Sacramento River (and tributaries) above
Hamilton City; therefore, these criteria do not apply to these
waters.
General Notes to Table in Paragraph (b)(1)
1. The table in this paragraph (b)(1) lists all of EPA's
priority toxic pollutants whether or not criteria guidance are
available. Blank spaces indicate the absence of national section
304(a) criteria guidance. Because of variations in chemical
nomenclature systems, this listing of toxic pollutants does not
duplicate the listing in Appendix A to 40 CFR Part 423-126 Priority
Pollutants. EPA has added the Chemical Abstracts Service (CAS)
registry numbers, which provide a unique identification for each
chemical.
2. The following chemicals have organoleptic-based criteria
recommendations that are not included on this chart: zinc, 3-methyl-
4-chlorophenol.
[[Page 31717]]
3. Freshwater and saltwater aquatic life criteria apply as
specified in paragraph (c)(3) of this section.
(2) Factors for Calculating Metals Criteria. Final CMC and CCC
values should be rounded to two significant figures.
(i) CMC = WER x (Acute Conversion Factor) x (exp{mA[1n
(hardness)]+bA})
(ii) CCC = WER x (Acute Conversion Factor) x
(exp{mC[1n (hardness)]+bC})
(iii) Table 1 to paragraph (b)(2) of this section:
----------------------------------------------------------------------------------------------------------------
Metal mA bA mC bC
----------------------------------------------------------------------------------------------------------------
Cadmium......................................... 1.128 -3.6867 0.7852 -2.715
Copper.......................................... 0.9422 -1.700 0.8545 -1.702
Chromium (III).................................. 0.8190 3.688 0.8190 1.561
Lead............................................ 1.273 -1.460 1.273 -4.705
Nickel.......................................... 0.8460 2.255 0.8460 0.0584
Silver.......................................... 1.72 -6.52
Zinc............................................ 0.8473 0.884 0.8473 0.884
----------------------------------------------------------------------------------------------------------------
Note to Table 1: The term ``exp'' represents the base e exponential function.
(iv) Table 2 to paragraph (b)(2) of this section:
----------------------------------------------------------------------------------------------------------------
Conversion CF for CF a for
factor (CF) for freshwater CF for saltwater
Metal freshwater chronic saltwater chronic
acute criteria criteria acute criteria criteria
----------------------------------------------------------------------------------------------------------------
Antimony....................................... (d) (d) (d) (d)
Arsenic........................................ 1.000 1.000 1.000 1.000
Beryllium...................................... (d) (d) (d) (d)
Cadmium........................................ b 0.944 b 0.909 0.994 0.994
Chromium (III)................................. 0.316 0.860 (d) (d)
Chromium (VI).................................. 0.982 0.962 0.993 0.993
Copper......................................... 0.960 0.960 0.83 0.83
Lead........................................... b 0.791 b 0.791 0.951 0.951
Mercury........................................ ............... .............. .............. ..............
Nickel......................................... 0.998 0.997 0.990 0.990
Selenium....................................... ............... (c) 0.998 0.998
Silver......................................... 0.85 (d) 0.85 (d)
Thallium....................................... (d) (d) (d) (d)
Zinc........................................... 0.978 0.986 0.946 0.946
----------------------------------------------------------------------------------------------------------------
Footnotes to Table 2 of Paragraph (b)(2):
a Conversion Factors for chronic marine criteria are not currently available. Conversion Factors for acute
marine criteria have been used for both acute and chronic marine criteria.
b Conversion Factors for these pollutants in freshwater are hardness dependent. CFs are based on a hardness of
100 mg/l as calcium carbonate (CaCO3). Other hardness can be used; CFs should be recalculated using the
equations in table 3 to paragraph (b)(2) of this section.
c Bioaccumulative compound and inappropriate to adjust to percent dissolved.
d EPA has not published an aquatic life criterion value.
Note to Table 2 of Paragraph (b)(2): The term ``Conversion
Factor'' represents the recommended conversion factor for converting
a metal criterion expressed as the total recoverable fraction in the
water column to a criterion expressed as the dissolved fraction in
the water column. See ``Office of Water Policy and Technical
Guidance on Interpretation and Implementation of Aquatic Life Metals
Criteria'', October 1, 1993, by Martha G. Prothro, Acting Assistant
Administrator for Water available from Water Resource Center, USEPA,
Mailcode RC4100, M Street SW, Washington, DC, 20460 and the note to
Sec. 131.36(b)(1).
(v) Table 3 to paragraph (b)(2) of this section:
------------------------------------------------------------------------
Acute Chronic
------------------------------------------------------------------------
Cadmium..................... CF=1.136672--[(ln CF = 1.101672--[(ln
{hardness}) {hardness})(0.04183
(0.041838)]. 8)]
Lead........................ CF=1.46203--[(ln CF = 1.46203--[(ln
{hardness})(0.14571 {hardness})(0.14571
2)]. 2)]
------------------------------------------------------------------------
(c) Applicability. (1) The criteria in paragraph (b) of this
section apply to the State's designated uses cited in paragraph (d) of
this section and apply concurrently with any criteria adopted by the
State, except when State regulations contain criteria which are more
stringent for a particular parameter and use, or except as provided in
footnotes p, q, and x to the table in paragraph (b)(1) of this section.
(2) The criteria established in this section are subject to the
State's general rules of applicability in the same way and to the same
extent as are other Federally-adopted and State-adopted numeric toxics
criteria when applied to the same use classifications including mixing
zones, and low flow values below which numeric standards can be
exceeded in flowing fresh waters.
(i) For all waters with mixing zone regulations or implementation
procedures, the criteria apply at the appropriate locations within or
at the boundary of the mixing zones; otherwise the criteria apply
throughout the water body including at the point of discharge into the
water body.
(ii) The State shall not use a low flow value below which numeric
standards can be exceeded that is less stringent than the flows in
Table 4 to paragraph (c)(2) of this section for streams and rivers.
(iii) Table 4 to paragraph (c)(2) of this section:
[[Page 31718]]
------------------------------------------------------------------------
Criteria Design flow
------------------------------------------------------------------------
Aquatic Life Acute Criteria (CMC)......... 1 Q 10 or 1 B 3
Aquatic Life Chronic Criteria (CCC)....... 7 Q 10 or 4 B 3
Human Health Criteria..................... Harmonic Mean Flow
------------------------------------------------------------------------
Note to Table 4 of Paragraph (c)(2): 1. CMC (Criteria Maximum
Concentration) is the water quality criteria to protect against
acute effects in aquatic life and is the highest instream
concentration of a priority toxic pollutant consisting of a short-
term average not to be exceeded more than once every three years on
the average.
2. CCC (Continuous Criteria Concentration) is the water quality
criteria to protect against chronic effects in aquatic life and is
the highest in stream concentration of a priority toxic pollutant
consisting of a 4-day average not to be exceeded more than once
every three years on the average.
3. 1 Q 10 is the lowest one day flow with an average recurrence
frequency of once in 10 years determined hydrologically.
4. 1 B 3 is biologically based and indicates an allowable
exceedence of once every 3 years. It is determined by EPA's
computerized method (DFLOW model).
5. 7 Q 10 is the lowest average 7 consecutive day low flow with
an average recurrence frequency of once in 10 years determined
hydrologically.
6. 4 B 3 is biologically based and indicates an allowable
exceedence for 4 consecutive days once every 3 years. It is
determined by EPA's computerized method (DFLOW model).
(iv) If the State does not have such a low flow value below which
numeric standards do not apply, then the criteria included in paragraph
(d) of this section apply at all flows.
(v) If the CMC short-term averaging period, the CCC four-day
averaging period, or once in three-year frequency is inappropriate for
a criterion or the site to which a criterion applies, the State may
apply to EPA for approval of an alternative averaging period,
frequency, and related design flow. The State must submit to EPA the
bases for any alternative averaging period, frequency, and related
design flow. Before approving any change, EPA will publish for public
comment, a document proposing the change.
(3) The freshwater and saltwater aquatic life criteria in the
matrix in paragraph (b)(1) of this section apply as follows:
(i) For waters in which the salinity is equal to or less than 1
part per thousand 95% or more of the time, the applicable criteria are
the freshwater criteria in Column B;
(ii) For waters in which the salinity is equal to or greater than
10 parts per thousand 95% or more of the time, the applicable criteria
are the saltwater criteria in Column C except for selenium in the San
Francisco Bay estuary where the applicable criteria are the freshwater
criteria in Column B (refer to footnotes p and q to the table in
paragraph (b)(1) of this section); and
(iii) For waters in which the salinity is between 1 and 10 parts
per thousand as defined in paragraphs (c)(3)(i) and (ii) of this
section, the applicable criteria are the more stringent of the
freshwater or saltwater criteria. However, the Regional Administrator
may approve the use of the alternative freshwater or saltwater criteria
if scientifically defensible information and data demonstrate that on a
site-specific basis the biology of the water body is dominated by
freshwater aquatic life and that freshwater criteria are more
appropriate; or conversely, the biology of the water body is dominated
by saltwater aquatic life and that saltwater criteria are more
appropriate. Before approving any change, EPA will publish for public
comment a document proposing the change.
(4) Application of metals criteria. (i) For purposes of calculating
freshwater aquatic life criteria for metals from the equations in
paragraph (b)(2) of this section, for waters with a hardness of 400 mg/
l or less as calcium carbonate, the actual ambient hardness of the
surface water shall be used in those equations. For waters with a
hardness of over 400 mg/l as calcium carbonate, a hardness of 400 mg/l
as calcium carbonate shall be used with a default Water-Effect Ratio
(WER) of 1, or the actual hardness of the ambient surface water shall
be used with a WER. The same provisions apply for calculating the
metals criteria for the comparisons provided for in paragraph
(c)(3)(iii) of this section.
(ii) The hardness values used shall be consistent with the design
discharge conditions established in paragraph (c)(2) of this section
for design flows and mixing zones.
(iii) The criteria for metals (compounds #1--#13 in the table in
paragraph (b)(1) of this section) are expressed as dissolved except
where otherwise noted. For purposes of calculating aquatic life
criteria for metals from the equations in footnote i to the table in
paragraph (b)(1) of this section and the equations in paragraph (b)(2)
of this section, the water effect ratio is generally computed as a
specific pollutant's acute or chronic toxicity value measured in water
from the site covered by the standard, divided by the respective acute
or chronic toxicity value in laboratory dilution water. To use a water
effect ratio other than the default of 1, the WER must be determined as
set forth in Interim Guidance on Determination and Use of Water Effect
Ratios, U.S. EPA Office of Water, EPA-823-B-94-001, February 1994, or
alternatively, other scientifically defensible methods adopted by the
State as part of its water quality standards program and approved by
EPA. For calculation of criteria using site-specific values for both
the hardness and the water effect ratio, the hardness used in the
equations in paragraph (b)(2) of this section must be determined as
required in paragraph (c)(4)(ii) of this section. Water hardness must
be calculated from the measured calcium and magnesium ions present, and
the ratio of calcium to magnesium should be approximately the same in
standard laboratory toxicity testing water as in the site water.
(d)(1) Except as specified in paragraph (d)(3) of this section, all
waters assigned any aquatic life or human health use classifications in
the Water Quality Control Plans for the various Basins of the State
(``Basin Plans'') adopted by the California State Water Resources
Control Board (``SWRCB''), except for ocean waters covered by the Water
Quality Control Plan for Ocean Waters of California (``Ocean Plan'')
adopted by the SWRCB with resolution Number 90-27 on March 22, 1990,
are subject to the criteria in paragraph (d)(2) of this section,
without exception. These criteria apply to waters identified in the
Basin Plans. More particularly, these criteria apply to waters
identified in the Basin Plan chapters designating beneficial uses for
waters within the region. Although the State has adopted several use
designations for each of these waters, for purposes of this action, the
specific standards to be applied in paragraph (d)(2) of this section
are based on the presence in all waters of some aquatic life
designation and the presence or absence of the MUN use designation
(municipal and domestic supply). (See Basin Plans for more detailed use
definitions.)
(2) The criteria from the table in paragraph (b)(1) of this section
apply to the water and use classifications defined in paragraph (d)(1)
of this section as follows:
[[Page 31719]]
------------------------------------------------------------------------
Water and use classification Applicable criteria
------------------------------------------------------------------------
(i) All inland waters of the United (A) Columns B1 and B2--all
States or enclosed bays and estuaries pollutants
that are waters of the United States (B) Columns C1 and C2--all
that include a MUN use designation. pollutants
(C) Column D1--all pollutants
------------------------------------------------------------------------
(ii) All inland waters of the United (A) Columns B1 and B2--all
States or enclosed bays and estuaries pollutants
that are waters of the United States (B) Columns C1 and C2--all
that do not include a MUN use pollutants
designation. (C) Column D2--all pollutants
------------------------------------------------------------------------
(3) Nothing in this section is intended to apply instead of
specific criteria, including specific criteria for the San Francisco
Bay estuary, promulgated for California in the National Toxics Rule at
Sec. 131.36.
(4) The human health criteria shall be applied at the State-adopted
10 (-6) risk level.
(5) Nothing in this section applies to waters located in Indian
Country.
(e)Schedules of compliance. (1) It is presumed that new and
existing point source dischargers will promptly comply with any new or
more restrictive water quality-based effluent limitations (``WQBELs'')
based on the water quality criteria set forth in this section.
(2) When a permit issued on or after May 18, 2000 to a new
discharger contains a WQBEL based on water quality criteria set forth
in paragraph (b) of this section, the permittee shall comply with such
WQBEL upon the commencement of the discharge. A new discharger is
defined as any building, structure, facility, or installation from
which there is or may be a ``discharge of pollutants'' (as defined in
40 CFR 122.2) to the State of California's inland surface waters or
enclosed bays and estuaries, the construction of which commences after
May 18, 2000.
(3) Where an existing discharger reasonably believes that it will
be infeasible to promptly comply with a new or more restrictive WQBEL
based on the water quality criteria set forth in this section, the
discharger may request approval from the permit issuing authority for a
schedule of compliance.
(4) A compliance schedule shall require compliance with WQBELs
based on water quality criteria set forth in paragraph (b) of this
section as soon as possible, taking into account the dischargers'
technical ability to achieve compliance with such WQBEL.
(5) If the schedule of compliance exceeds one year from the date of
permit issuance, reissuance or modification, the schedule shall set
forth interim requirements and dates for their achievement. The dates
of completion between each requirement may not exceed one year. If the
time necessary for completion of any requirement is more than one year
and is not readily divisible into stages for completion, the permit
shall require, at a minimum, specified dates for annual submission of
progress reports on the status of interim requirements.
(6) In no event shall the permit issuing authority approve a
schedule of compliance for a point source discharge which exceeds five
years from the date of permit issuance, reissuance, or modification,
whichever is sooner. Where shorter schedules of compliance are
prescribed or schedules of compliance are prohibited by law, those
provisions shall govern.
(7) If a schedule of compliance exceeds the term of a permit,
interim permit limits effective during the permit shall be included in
the permit and addressed in the permit's fact sheet or statement of
basis. The administrative record for the permit shall reflect final
permit limits and final compliance dates. Final compliance dates for
final permit limits, which do not occur during the term of the permit,
must occur within five years from the date of issuance, reissuance or
modification of the permit which initiates the compliance schedule.
Where shorter schedules of compliance are prescribed or schedules of
compliance are prohibited by law, those provisions shall govern.
(8) The provisions in this paragraph (e), Schedules of compliance,
shall expire on May 18, 2005.
[FR Doc. 00-11106 Filed 5-17-00; 8:45 am]
BILLING CODE 6560-50-P
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