Announcement of Regulatory Determinations for Priority
Contaminants on the Drinking Water Contaminant Candidate List
[Federal Register: July 18, 2003 (Volume 68, Number 138)]
[Notices]
[Page 42897-42906]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr18jy03-191]
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ENVIRONMENTAL PROTECTION AGENCY
[FRL-7529-2]
Announcement of Regulatory Determinations for Priority
Contaminants on the Drinking Water Contaminant Candidate List
AGENCY: Environmental Protection Agency.
ACTION: Notice.
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SUMMARY: The Safe Drinking Water Act (SDWA), as amended in 1996,
directs the United States Environmental Protection Agency (EPA) to
publish a list of contaminants (referred to as the Contaminant
Candidate List, or CCL) to assist in priority-setting efforts for the
Agency's drinking water program. SDWA also directs the Agency to select
five or more contaminants every five years from the current CCL and
determine whether or not to regulate these contaminants with a National
Primary Drinking Water Regulation (NPDWR).
On June 3, 2002, EPA published preliminary regulatory
determinations for nine contaminants together with the determination
process, rationale, and supporting technical information for each
contaminant to seek comment from the public (67 FR 38222). The nine
contaminants include three inorganic compounds (IOCs) (manganese,
sodium, and sulfate); three synthetic organic compounds (SOCs) (aldrin,
dieldrin, and metribuzin); two volatile organic compounds (VOCs)
(hexachlorobutadiene and naphthalene); and one microbial contaminant,
Acanthamoeba. EPA's preliminary determination was that no regulatory
action was appropriate for any of the nine contaminants.
EPA received 15 comments from individuals or organizations on the
preliminary regulatory determinations for the nine contaminants. The
Agency has reviewed these comments and, after careful consideration,
decided that no regulatory action is appropriate, at this time, for the
nine CCL contaminants published in the June 2002 notice. Regulation of
the nine contaminants would not present a meaningful opportunity for
health risk reduction for persons served by public water systems
(PWSs).
Today's action describes the statutory requirements for the CCL,
the analysis EPA used to make the regulatory determinations, a summary
of relevant public comments with the Agency's responses, a summary of
the nine CCL contaminants, and the Agency's findings for each
contaminant.
ADDRESSES: The official public docket for this action is located at
EPA's West Building, Room B-102, 1301 Constitution Avenue, NW.,
Washington, DC.
FOR FURTHER INFORMATION CONTACT: For copies of, and general information
about this document or information about the nine contaminants
discussed in this action, contact the Safe Drinking Water Hotline.
Callers within the United States may reach the Hotline at (800) 426-
4791 or its local number (703) 412-3330. The Hotline is open Monday
through Friday, excluding Federal holidays, from 9 a.m. to 5:30 p.m.,
Eastern Time. For technical inquiries contact: Thomas Carpenter (202)
564-4885, e-mail: carpenter.thomas@epa.gov or Harriet Colbert, (202)
564-4698, e-mail: colbert.harriet@epa.gov.
SUPPLEMENTARY INFORMATION
I. General Information
A. Does This Notice Apply to My Public Water System?
Today's action does not impose any requirements on anyone. Instead,
it notifies interested parties of EPA's responses to comments received
on EPA's preliminary determination and of EPA's final determination not
to regulate nine CCL contaminants.
B. How Can I Get Copies of Related Information?
1. Docket. EPA has established an official public docket for this
action under Docket ID No. OW-2002-0021. The official public docket is
the collection of materials that is available for public viewing at the
Water Docket in the EPA Docket Center, (EPA/DC) EPA West, Room B102,
1301 Constitution Avenue, NW., Washington, DC. The EPA Docket Center
Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through
Friday, excluding legal holidays. The telephone number for the Public
Reading Room is (202) 566-1744, and the telephone number for the Water
Docket is (202) 566-2426.
2. Electronic Access. You may access this Federal Register document
electronically through the EPA Internet under the ``Federal Register''
listings at http://www.epa.gov/fedrgstr/.
An electronic version of the public docket is available through
EPA's electronic public docket and comment system, EPA Dockets. You may
use EPA Dockets at http://www.epa.gov/edocket/ to view public comments,
access the index listing of the contents of the official public docket,
and to access those documents in the public docket that are available
electronically. Although not all docket materials may be available
electronically, you may still access any of the publicly available
docket materials through the docket facility identified in section
I.B.1. Once in the system, select ``search,'' then key in the
appropriate docket identification number.
Abbreviations and Acronyms Used in This Action
ATSDR Agency for Toxic Substances and Disease Registry
AWQC Ambient Water Quality Criteria
CASRN Chemical Abstract Services Registry Number
CCL Contaminant Candidate List
CWS Community Water Supply
EPA U.S. Environmental Protection Agency
FDA U.S. Food and Drug Administration
FR Federal Register
g gram
HRL Health reference level
IOC Inorganic compound
kg Kilogram
L Liter
MCL Maximum contaminant level
MCLG Maximum contaminant level goal mg milligram
MTBE Methyl-t-butyl ether
NDWAC National Drinking Water Advisory Council
NIRS National Inorganic and Radionuclide Survey
NPDWR National Primary Drinking Water Regulation
NRC National Research Council
OPP Office of Pesticides Program
ORD Office of Research and Development
PWS Public Water System
RSC Relative Source Contribution
SAB Science Advisory Board
SDWA Safe Drinking Water Act
SOC Synthetic organic compound
TRI Toxic Release Inventory
UCM Unregulated Contaminant Monitoring
USEPA United States Environmental Protection Agency
USGS United States Geological Survey
VOC Volatile organic compound
II. Background
A. What Is the Statutory Requirement for the Contaminant Candidate
List?
SDWA, as amended in 1996, directs EPA to publish a list of
contaminants (referred to as the Contaminant Candidate List, or CCL) to
assist the Agency in priority-setting efforts. The CCL is a list of
contaminants which are not subject to any proposed or promulgated
NPDWRs, are known or anticipated to occur in PWSs, and may require
regulation under SDWA.
[[Page 42899]]
The first CCL was developed with considerable input from the
scientific community and stakeholders. EPA published a draft CCL
requesting public comment on October 6, 1997 (62 FR 52193, USEPA 1997).
The first final CCL was published on March 2, 1998 (63 FR 10273, USEPA
1998). The SDWA requires that a new CCL be published every five years.
EPA is currently preparing the next CCL. The March 1998 CCL contained
60 contaminants, including 50 chemicals or chemical groups and 10
microbiological contaminants or microbial groups. Many of these
contaminants lacked some of the information necessary to support a
regulatory determination and were identified in the March 1998 CCL
notice (USEPA 1998) as having data needs. The 60 CCL contaminants were
divided into categories to represent research and data needs associated
with each contaminant. The categories were: (1) Regulatory
determination priorities; (2) health effects research priorities; (3)
treatment research priorities; (4) analytical methods research
priorities; and (5) occurrence priorities.
In 1998, 20 of the 60 contaminants were classified as regulatory
determination priorities because EPA believed that, at that time, there
was sufficient data for these contaminants to evaluate both exposure
and risk to public health and to support a determination of whether or
not to proceed to promulgation of a NPDWR. Since the March 1998 CCL,
EPA found that there was insufficient information, in the Agency's
judgement, to support a regulatory determination for 12 of the 20
priority contaminants. In addition, the CCL-contaminant, sodium, was
reclassified and added to the list of regulatory determination
priorities as a means of reassessing the current guidance level for
sodium. Thus, EPA is now presenting regulatory determinations for nine
priority contaminants that have sufficient information to support a
regulatory determination at this time.
The Agency however, continues to conduct research and/or to collect
occurrence information on the remaining 51 CCL contaminants. EPA has
been aggressively conducting research to fill in the data gaps and
recognizes that stakeholders may have a particular interest in the
timing of future regulatory determinations for other contaminants on
the CCL. Stakeholders may be concerned that regulatory determinations
for such contaminants should not necessarily wait until the end of the
next regulatory determination cycle. In this regard, it is important to
recognize that the Agency is not precluded from monitoring, conducting
research, developing guidance, or regulating contaminants not included
on the CCL as necessary and appropriate (see SDWA sections
1412(b)(1)(B)(ii)(III) and 1412(b)(1)(F)), or from taking action on CCL
contaminants when information becomes available. Thus, some regulatory
determinations may be made before the end of the next regulatory
determination cycle (i.e., August 2006).
B. What Contaminants Did EPA Consider for Regulation?
EPA published preliminary regulatory determinations in the June 3,
2002, edition of the Federal Register (67 FR 38222, USEPA 2002a) for
nine priority contaminants that have sufficient information to support
a regulatory determination at this time. The nine contaminants include
three IOCs (manganese, sodium, and sulfate); three SOCs (aldrin,
dieldrin, and metribuzin); two VOCs (hexachlorobutadiene and
naphthalene); and one microbial contaminant, Acanthamoeba. Information
for each of the nine CCL contaminants is available in the EPA Fact
Sheet (USEPA 2002b), in the Health Effects Support Documents or
Drinking Water Advisories for each of the nine CCL contaminants (2003a-
h), and in the regulatory determination support documents (USEPA 2001a-
g). This information is available at the Water Docket (No. OW-2002-021)
and is also available on EPA's Safe Drinking Water Regulatory
Determination website at http://www.epa.gov/safewater/ccl/
cclregdetermine.html. Brief descriptions of each of the nine CCL
contaminants considered for regulatory determinations are included in
section V of this notice.
III. What Analyses Did EPA Use To Make the Regulatory Determinations?
The precepts for guiding EPA in making regulatory determinations
for a drinking water contaminant are included in Section 1412(b)(1)(A)
of SDWA. This section of SDWA requires EPA to consider the following
three evaluation criteria prior to making a regulatory decision: (1)
Potential adverse health effects from the contaminant; (2) occurrence
of the contaminant in PWSs with a frequency and at levels of public
health concern; and (3) whether regulation of the contaminant would
present a meaningful opportunity for health risk reduction for persons
served by PWSs.
EPA developed a comprehensive approach for making regulatory
determinations with significant expert input and recommendations
suggested by the National Research Council (NRC), National Drinking
Water Advisory Council (NDWAC), and stakeholders. The regulatory
determination approach is largely based on the NDWAC recommendations.
For each of the nine contaminants, EPA evaluated the best available
peer reviewed data on health effects, and approximately seven million
analytical data points on contaminant occurrence. For those
contaminants with adequate monitoring methods, as well as health
effects and occurrence data, EPA applied an approach in making
regulatory determinations that followed the NDWAC recommendations and
complies with the SDWA requirements under Section 1412(b)(1)(A). In
June 2002, EPA consulted with the Science Advisory Board (SAB) Drinking
Water Committee and requested its review and comment on whether the
protocol EPA developed, based on the NDWAC recommendations, was
consistently applied and appropriately documented. The SAB provided
verbal feedback regarding the use of the NRC and NDWAC recommendations
in EPA's decision criteria for making its regulatory determinations, as
well as its interest in remaining involved in future regulatory
determinations. SAB recommended that the Agency provide a transparent
and clear explanation of the process for making regulatory
determinations. In today's announcement and in the documentation
supporting this announcement, the Agency has taken the SAB
recommendation into consideration in explaining the evaluation process
used to make today's regulatory determinations.
EPA characterized the human health effects that may result from
exposure to a contaminant found in drinking water. Based on this
characterization, EPA estimated a health reference level (HRL) or
benchmark value for each contaminant. EPA has prepared Health Effects
Support Documents or Drinking Water Advisories (USEPA 2002c and 2003a-
g) for each contaminant, which are available at the EPA Water Docket
and on-line at http://www.epa.gov/edocket/. The support documents
address the following: Exposure from drinking water and other media;
toxicokinetics; hazard identification; dose-response assessment; and an
overall characterization of risk from drinking water.
Using the Agency's Unregulated Contaminant Monitoring (UCM) program
data and National Inorganic and Radionuclide Survey (NIRS) data, EPA
estimated the number of PWSs and the population served by the PWSs at
the benchmark values, and the
[[Page 42900]]
geographic distribution, using a large amount of State occurrence data
that are generally indicative of national occurrence. The UCM data form
part of the Agency's basis for its estimates of national occurrence
since these data provide occurrence information for several unregulated
contaminants. The NIRS data provide a statistically representative
sample of the national occurrence of many other unregulated and
regulated inorganic contaminants in ground water community water
supplies (CWSs).
EPA also employed other State drinking water data, use and
environmental release information (e.g., EPA's Toxic Release Inventory
(TRI), academic and private sector publications), as well as ambient
water quality data (i.e., source water existing in surface waters and
aquifers before extraction and treatment as drinking water), to augment
the UCM drinking water data and to evaluate the likelihood of
contaminant occurrence. EPA included, when available, data from the
U.S. Geological Survey's (USGS) National Water Quality Assessment
program.
A detailed discussion of the data collected and analyses for each
contaminant can be found in the respective regulatory determination
support document. The regulatory determination support documents (USEPA
2001a-g) are available in the EPA Water Docket.
The underlying data and analysis supporting the findings used by
the Agency to make the regulatory determinations are summarized in the
June 2002 notice (USEPA 2002a).
IV. Summary of Public Comments and the Agency's Responses on the CCL
Regulatory Determination Process
The comment period on the June 3, 2002, notice ended on August 2,
2002. EPA received 15 comments on the preliminary regulatory
determinations for the nine CCL contaminants published by EPA in the
June 2002 notice (USEPA 2002a). Four comments were received from water
systems and related associations, seven from industry groups, two from
environmental advocacy groups, one from a State agency and one from a
State-related association. Although most commenters generally approved
of EPA's determination not to regulate any new contaminants at this
time, some commenters expressed concerns about the process associated
with EPA's regulatory determinations for these nine contaminants, as
well as with CCL activities not specifically related to the preliminary
determinations.
A majority of the comments were focused on five over-arching topic
areas:
1. Some commenters expressed concern over the transparency of the
CCL decision-making process.
2. Several industry groups expressed a concern that the health
effects assessments were too conservative.
3. Several commenters expressed concern with EPA's progress in
filling research gaps related to the CCL and encouraged EPA to publicly
track research needs and progress on remaining CCL contaminants.
4. The majority of commenters generally approved of EPA's
determination not to regulate any new contaminants at this time.
However, one commenter questioned the appropriateness of EPA's
decisions not to regulate any of the nine priority contaminants.
5. Several comments were received regarding contaminants on the CCL
for which draft regulatory determinations were not included in the June
2002 notice, including perchlorate and methyl-t-butyl ether (MTBE).
A complete copy of the public comments and the Agency's responses
are included in the Docket for today's action. The remainder of this
section discusses the five key topic areas identified by commenters in
response to the June 2002 CCL regulatory determination notice (USEPA
2002a).
1. Lack of Transparency of Regulatory Determination Approach
Comment Summary: Several commenters expressed a concern about the
``lack of transparency'' in the regulatory determination approach used
by the Agency for the June 2002 notice. Most of those commenters
suggested that EPA did not provide an adequate explanation for the
reduction in the number of the priority contaminants from twenty to
nine since the publication of the first CCL in March 1998 (USEPA 1998).
These commenters suggested that the Agency needs to provide better
justification regarding the reasons for excluding the twelve
contaminants listed in the March 1998 CCL from the regulatory
determination process.
Several commenters suggested that this regulatory determination
process approach does not provide for enough participation from outside
groups for the development of non-regulatory strategies. These
commenters suggested that the Agency should allow for more meaningful
public involvement in the regulatory determination process. One
commenter stated that, given the Agency's analysis of occurrence and
health effects data over several years, the 60-day comment period was
not adequate to allow ``detailed analysis by interested stakeholders.''
Other commenters, however, observed that the CCL regulatory
determination approach taken by EPA was ``reliably consistent'' with
the basic charge of the SDWA and the NDWAC workgroup recommendations.
Several commenters noted that, by EPA following the protocol
recommended by the NDWAC Work Group, stakeholders were assured that the
Agency used the ``best-available, peer-reviewed science'' in these
determinations.
Agency Response: EPA developed a consistent regulatory
determination approach for evaluating CCL contaminants that followed
NDWAC's recommended protocol for health effects and occurrence
analysis. The regulatory determination approach for each contaminant on
the list included an evaluation of the adequacy of current analytical
and treatment methods, the best available peer-reviewed data on health
effects, and an occurrence data set of about seven million contaminant
occurrence data points.
By using this approach, EPA determined that, at the time of the
June 2002 notice (USEPA 2002a) of preliminary regulatory determinations
there was not sufficient information to support a regulatory
determination on twelve of the twenty priority contaminants. As noted
previously, the CCL-contaminant, sodium, was moved to the list of
regulatory determination priorities to allow an update of the Agency's
position on the issue of sodium in drinking water.
The NDWAC, which is comprised of representatives from the general
public, State and local agencies, and private groups concerned with
drinking water safety, was convened to provide input during the
regulatory determination process. Throughout the regulatory
determination process, EPA's approach has been to maintain a strong
partnership with stakeholders and involve them to the maximum extent
possible, thereby helping to ensure that stakeholders understand the
regulatory determination process and provide valuable input.
The Agency agrees that a meaningful opportunity for discussions
with stakeholders is an important component of the CCL Regulatory
Determination process. The Agency utilized a variety of mechanisms to
involve stakeholders in the process. These included two broad-based
stakeholder meetings, one in November 1999 and one in July 2002.
Members of the public also were invited to attend the three sessions of
the NDWAC Work Group in the Spring/
[[Page 42901]]
Summer of 2000, which focused on protocol recommendations to the
Agency. In addition, EPA representatives delivered presentations at a
variety of meetings held by other organizations. Moreover, EPA did ask
for and considered comments made on the sodium and sulfate Drinking
Water Advisories during the comment period on the June 2002 notice
(USEPA 2002a).
The Agency believes the 60-day public comment period for the June
2002 notice (USEPA 2002a) was sufficient. The Agency took steps to
facilitate public review of its preliminary decisions, as well as
supporting documentation. In addition to the July 2002 stakeholder
meeting, these steps included making key materials available on the
Agency's website and providing hard copies of materials upon request.
2. Health Effects Assessments
Comment Summary: Some commenters suggested that EPA's analysis of
adverse health effects and calculation of the HRLs were too
conservative. On the other hand, one commenter questioned how the
Agency's analysis underlying the regulatory determination approach
incorporated appropriate safety factors and exposure assessments
relative to children's health concerns.
Commenters recommended that EPA use the revised Office of Water
methodology for deriving ambient water quality criteria (AWQC), (USEPA
2000), in an effort to protect human health in the final health effects
support documents. According to the comments, this revised methodology
establishes five different consumption rates and body weight
classifications as a means to make the human health exposure
assessments. One commenter specified that EPA needs to use more
accurate consumption data for sodium rather than simply incorporating
U.S. Food and Drug Administration (FDA) assertions.
Agency Response: EPA believes it is appropriate to use a
conservative approach to assessing the health effects of an unregulated
contaminant in the context of a determination of whether it should be
considered for NPDWR regulation. In order to determine whether to
propose an NPDWR for an unregulated contaminant, SDWA requires EPA to
determine whether the contaminant ``may have an adverse effect on the
health of the persons,'' Section 1412(b)(1)(A)(i), which is a very
broad criterion. As a result, EPA believes that a conservative health
effects analysis is appropriate.
The HRL used by EPA in these determinations is a conservative
health-based value and is different depending on whether a contaminant
is considered a carcinogen or a noncarcinogen. For carcinogens, a 10-6
risk was chosen as the HRL since the maximum contaminant level goal
(MCLG) for such contaminants will generally be zero. For
noncarcinogens, the reference dose and a 20 percent relative source
contribution (RSC) factor was used in conjunction with a 70 kilogram
(kg) adult body weight and a 2 liter (L) water intake for the HRL
calculation. EPA uses these standard regulatory assumptions for
determining the MCLG of a noncarcinogen that lacks specific data on the
RSC. EPA used best available peer reviewed data and analyses in
evaluating adverse health effects. Accordingly, EPA disagrees with
those commenters that felt that EPA was too conservative in
establishing the HRL. EPA followed practices and policies that are
similar to those used to establish an NPDWR and that are consistent
with the SDWA section 1412(b)(1)(A)(i) criterion. If such a
conservative approach does not result in EPA deciding to initiate a
regulatory process for a contaminant, the Agency may decide to use a
non-regulatory approach in addressing the issue, such as issuing a
Drinking Water Advisory.
Children's health issues were considered in making regulatory
determinations for each of the nine contaminants included in this final
notice. The details of the individual assessments are included in the
Health Effects Support Documents or Drinking Water Advisories for each
contaminant. These documents are available for review at the EPA Water
Docket and on-line at http://www.epa.gov/edocket/.
The AWQC (USEPA 2000) methodology continues to recommend the use of
70 kg for adult body weight and 2 liters per day for water intake for
risk calculations. These are the same parameters used by EPA to derive
an MCLG. EPA believes that its current methodology, based on adult
exposures, for the derivation of MCLGs, and for making regulatory
determinations under SDWA section 1412, remains generally appropriate.
EPA has not yet determined a protocol for making a regulatory
determination for a chemical for which an infant's or a particular
childhood age grouping's body weight and drinking water intake would be
the basis of a regulatory action. A decision for such a contaminant
would be made on the basis of the toxicity and exposure data, and could
utilize the age groupings and body weight information from the AWQC
human health methodology if it were appropriate.
EPA did not use FDA's sodium consumption data of 4 to 6 grams/day
(g/day) in establishing a benchmark value for sodium. EPA decided to
use a benchmark value for sodium instead of an HRL because sodium lacks
suitable dose-response data and there is considerable controversy
regarding the role of sodium in the etiology of hypertension. EPA
derived the benchmark value for sodium of 120 mg/L in drinking water
from the National Institutes of Health, National Academy of Sciences,
American Heart Association, and the U.S. Department of Agriculture
recommended daily dietary intake of 2.4 g/day.
3. EPA Research Agenda
Comment Summary: Several commenters expressed concern that, in
their view, there is a lack of progress by EPA in filling research gaps
related to the CCL. In particular, commenters focused on high
visibility contaminants, such as the microbiological contaminants,
MTBE, and other ``emerging contaminants.'' Commenters also stressed the
need to establish a vehicle for publicly tracking research needs and
progress made in research areas.
Agency Response: Before EPA can determine whether to regulate
contaminants, additional data on health, treatment technologies, and
analytical methods, are needed for contaminants on the Research
Priorities portion of the CCL, and occurrence data is needed for
contaminants on the Occurrence Data Needs portion of the CCL. The
remaining 51 CCL contaminants for which decisions are not being made
today do not have sufficient data to support a regulatory
determination. The Agency considers obtaining this data to be the
priority of its research and occurrence monitoring programs. The Agency
continues to actively conduct research and/or to collect occurrence
information on these 51 CCL contaminants and other emerging
contaminants. Because these research issues are broader than those that
EPA can address alone, it is anticipated that other entities will be
involved in conducting much of the needed research to support this
process. For example, EPA already is jointly undertaking research
efforts, and encourages stakeholders, through close and regular
consultation, to be partners in filling many of the research gaps. The
EPA continues to identify and develop new collaborations to conduct
research and gather the additional data to characterize occurrence and
adverse
[[Page 42902]]
health effects to support future regulatory determinations of CCL
contaminants. EPA is also engaged with our stakeholders in a NDWAC work
group to refine the CCL listing process to address emerging
contaminants for future efforts.
EPA agrees with the comment concerning the importance of
establishing a vehicle that will allow stakeholders to track the status
of drinking water research projects. EPA is committed to providing a
means for stakeholders to track research needs and progress made in
research areas, and is developing a web-based research inventory that
is expected to be available to the public in 2003. This website will
serve as a repository of information on drinking water research
projects currently funded or performed by the EPA.
4. Criticism of Regulatory Decisions Made
Comment Summary: One commenter expressed concern that EPA's
decision not to regulate any of the nine priority contaminants was not
appropriate. A comment submitted and co-signed by 22 environmental
organizations disagreed with the regulatory determinations for four
contaminants, hexachlorobutadiene, manganese, sodium and sulfate. The
commenters believe that EPA's monitoring data presented in the June
2002 notice shows that over 22,000 people were exposed to
hexachlorobutadiene at concentrations above the HRL. The commenters
assert that although EPA says manganese has low toxicity, EPA finds
that nearly 3% of the population exceeded EPA's HRL. The commenters
also disagreed with the Agency determination that regulation is not
warranted because food sources of sodium are a more significant
contribution to sodium in the diet than drinking water. The commenters
also assert that EPA should regulate sulfate because EPA's monitoring
data shows that millions of Americans are likely to have sulfate levels
above the HRL in their drinking water, which puts infants and other
subpopulations at risk.
Agency Response: The preliminary regulatory determinations on
whether or not to regulate the nine priority contaminants were based on
the three SDWA statutory requirements, and the contaminants were
evaluated in terms of national significance. EPA's assessment of the
health effects and national occurrence were discussed in detail in the
June 2002 notice. EPA disagrees that each of the contaminants
identified by the commenters should be regulated. The rationale
supporting the regulatory determination is provided below.
EPA found that hexachlorobutadiene occurs in systems, but not at a
frequency or level of public health concern. The commenter has
misinterpreted the monitoring data presented in the June 2002 notice.
The number 22,736 in the notice refers to the number of reporting PWSs
in the monitoring data set and does not reflect the number of people
exposed to hexachlorobutadiene concentrations above the HRL. The June
2002 notice states that 0.02% (4 out of 22,736) reporting systems
detected hexachlorobutadiene above the HRL affecting 0.005% (3,350 out
of the 67 million) of the population served by these systems (67 FR
38235). Because of this low frequency, EPA believes it is most
appropriate at this time to address occurrence of hexachlorobutadiene
at the State level rather than at the national level.
EPA disagrees with the commenter's criticism of the decision not to
regulate manganese. Manganese is an essential trace element needed for
the normal healthy growth and function of animals as well as human
beings. Therefore, the decision whether or not to regulate manganese
needs to balance the concern for the potential toxic effects from high
oral exposure with the concern for adverse effects from manganese
deficiency. In 2001, the Institute of Medicine (IOM) set an adequate
level for manganese at 2.3 mg/day for men and 1.8 mg/day for woman.
Furthermore, in 2001, the IOM set a tolerable upper intake level
for manganese at 11 mg/day. While 3% of the population may be exposed
to manganese at levels above the 0.30 mg/L HRL for drinking water, this
level is well below the IOM tolerable level. For example, assuming a
daily intake of 2 liters of drinking water with manganese at the HRL of
0.30 mg/L, the daily intake of manganese from drinking water at the HRL
would only expose a person to 0.6 mg/day. This value is well below
IOM's 11 mg/L adequate level for manganese and represents only 5.5% of
IOM's upper limit for manganese. Public drinking water accounts for a
relatively small proportion of a person's manganese intake, even at the
HRL. Therefore, the Agency concludes that regulation of drinking water
for manganese does not provide a meaningful opportunity to reduce the
risk of adverse health effects. The commenter is referred to the CCL
Preliminary Regulatory Determination Support Document for Manganese
(EPA 815-R-01-013) for a more detailed discussion of this issue.
EPA disagrees with the commenter's criticism of the decision not to
regulate sodium. Because sodium in drinking water is a very small
contributor to daily dietary intake and because the levels at which
sodium intake can contribute to increasing the blood pressure of
individuals with normal blood pressures is not clearly established, EPA
does not believe that a NPDWR for sodium presents a meaningful
opportunity for public health protection at this time.
EPA disagrees with the commenter's criticism of the decision not to
regulate sulfate. EPA used current data (Round 2 of the UCM program)
that indicate that about 1.8% of the reporting systems serving
approximately 2 million people from a 20-state cross section of the
unregulated contaminant monitoring study exceeded 500 mg/L. Although
additional data from six states had very similar results, EPA found
that the weight of evidence suggests that the adverse health effect is
generally mild, of short duration, and generally occurs at
concentrations considerably greater than 500 mg/L, except in very
limited circumstances when contaminants that exacerbate the effects of
sulfate are also present in the water. Therefore, EPA has made the
determination not to regulate sulfate with a NPDWR at this time because
regulation would not present a meaningful opportunity for health risk
reduction for persons served by public drinking water systems. However,
EPA prepared a Drinking Water Advisory to provide guidance to
communities that may be exposed to drinking water with high sulfate
concentrations. This advisory contains information of use to sensitive
sub-populations, such as infants and travelers.
5. Stakeholder's Highest Priority for Future Regulatory Determinations
Comment Summary: Commenters encouraged EPA to be aggressive and
consider an expedited regulatory determination for several CCL
contaminants including MTBE and perchlorate.
Agency Response: For this regulatory determination, EPA developed a
comprehensive evaluation approach based on the recommendations from NRC
and NDWAC. As explained in the June 2002 notice (USEPA 2002a), this
evaluation satisfies the three SDWA requirements under section
1412(b)(1)(A)(i)-(iii). For each of the contaminants, the Agency
evaluated the adequacy of current analytical and treatment methods, the
best available peer-reviewed data on health effects, and an occurrence
data set of approximately seven million analytical data points. At this
time, EPA does not believe adequate data exists in these key areas to
make a regulatory
[[Page 42903]]
determination either for perchlorate or MTBE. EPA is gathering
information to fill the data gaps for these contaminants.
With respect to perchlorate, EPA is gathering national occurrence
data on perchlorate in drinking water through the Unregulated
Contaminant Monitoring (UCM) Rule. The Agency is also completing a
rigorous peer review of health effects studies and is developing a
final toxicity review and risk characterization. As part of this
effort, EPA has asked the National Academy of Sciences to review
science issues related to the 2002 draft EPA risk assessment for
perchlorate. In addition, the Agency is funding research studies on
treatability of perchlorate for PWSs. Some of the technology currently
in use at hazardous waste sites is being evaluated for the feasibility
of using it in water treatment at community water systems. At the same
time, EPA is seeking to improve the analytical method sensitivity that
would allow concentrations of perchlorate to be quantified at lower
levels than are presently possible. The Agency is moving concurrently
in each of these areas to meet data and research needs as quickly as
possible. When the necessary information is collected, we plan to move
forward with a regulatory determination. In this regard, it should be
emphasized that where EPA determines there is sufficient information on
this or any other unregulated contaminant, the Agency is prepared to
act in advance of the next five year regulatory determination cycle.
Regarding MTBE, on-going activities will provide the Agency with
improved health effects and occurrence data. At this time, EPA is
preparing its revised risk assessment for MTBE for peer review. The
Agency established the 1997 Drinking Water Advisory for MTBE at 20-40
micrograms per liter ([mu]g/L, or parts per billion, ppb) to avoid
unacceptable taste and odor and provide a protective margin of exposure
for adverse health effects. The 20-40 ppb level was not based on the
possible cancer risks. As a result of the UCM Rule, data from PWSs
required to monitor for MTBE will be available in the middle of 2004.
V. Summary of the Agency's Findings on the Nine CCL Contaminants
A. Acanthamoeba
Description: Acanthamoeba is a free-living protozoa commonly found
in water, soil, and air. Species of this microbe have been isolated
worldwide from brackish and sea water, tap water, bottled water,
airborne dust, swimming pools, hot springs, thermal effluents of power
plants, ocean sediments, vegetables, and hot tubs. Acanthamoeba species
have been associated with human infections affecting the eye, lung,
brain, and skin. Acanthamoeba has been recovered from the nose and
throat of humans with impaired respiratory function and from apparently
healthy persons, suggesting that the amoeba is commonly inhaled.
Agency Findings: After reviewing the best available public health
and occurrence information, EPA has made the determination not to
regulate Acanthamoeba with a NPDWR at this time, because regulation
would not present a meaningful opportunity for health risk reduction
for the people served by public drinking water systems (PWSs). As noted
in the June 2002 notice (USEPA 2002a), EPA has no national monitoring
data to indicate occurrence of Acanthamoeba cysts in drinking water,
and filtration practices commonly used to treat drinking water remove
Acanthamoeba cysts.
A complete review of EPA's analysis of the health effects,
occurrence, and exposure for Acanthamoeba were presented in the June
2002 notice (USEPA 2002a) and in the health effects support document
for Acanthamoeba (USEPA 2003h). EPA intends to release a guidance
document for Acanthamoeba that will be directed mainly to contact lens
wearers and will address the risks of Acanthamoeba eye infection
associated with improper care of contact lenses.
B. Aldrin and Dieldrin
Description: Aldrin and dieldrin (Chemical Abstract Services
Registry Number (CASRN) 309-00-2 and 60-57-1, respectively) are the
common names of two structurally similar insecticides. They are
discussed together because aldrin readily changes to dieldrin in the
body and in the environment, and they cause similar adverse health
effects. From 1950-1970, aldrin and dieldrin were popular pesticides
used for crops, such as corn and cotton. Because of concerns about
damage to the environment and the potential harm to human health, EPA
banned most uses of aldrin and dieldrin in 1974, except for the control
of termites, and banned all uses outright since 1987. According to the
Agency for Toxic Substances and Disease Registry (ATSDR), aldrin and
dieldrin have not been produced in the United States since 1974 (ATSDR
1993).
Agency Findings: After reviewing the best available public health
and occurrence information, EPA has made the determination not to
regulate aldrin or dieldrin with a NPDWR at this time, because
regulation would not present a meaningful opportunity for health risk
reduction for the people served by PWSs. EPA recognizes that aldrin and
dieldrin are probable human carcinogens, but the chemicals have been
banned for most uses since 1974, and have a low frequency and low level
of occurrence in drinking water supplies.
A complete review of EPA's analysis of the health effects,
occurrence, and exposure for aldrin and dieldrin were presented in the
June 2002 notice (USEPA 2002a) and in the regulatory determination
(USEPA 2001a) and health effects (USEPA 2003a) support documents for
aldrin and dieldrin.
C. Hexachlorobutadiene
Description: Hexachlorobutadiene (CASRN 87-68-3) is a VOC that is
relatively insoluble in water (solubility of 2-2.55 mg/L).
Hexachlorobutadiene is mainly used to make rubber compounds. It is also
used in gyroscopes, as a heat transfer liquid, as a hydraulic fluid, as
a solvent, and to make lubricants. It has never been manufactured as a
commercial product in the United States, however, it is imported and
significant quantities of the chemical are generated in the United
States as a waste by-product from the chlorination of hydrocarbons.
Most exposure to hexachlorobutadiene comes from breathing
contaminated air in the workplace environment. People living near
hazardous waste sites containing hexachlorobutadiene may be exposed to
it by breathing air or by drinking contaminated water.
Agency Findings: After reviewing the best available public health
and occurrence information, EPA has made the determination not to
regulate hexachlorobutadiene with a NPDWR at this time, because it
would not present a meaningful opportunity for health risk reduction
for persons served by PWSs. Hexachlorobutadiene occurs in PWSs, but not
at a frequency or level of public health concern.
A complete review of EPA's analysis of the health effects,
occurrence, and exposure for hexachlorobutadiene were presented in the
June 2002 notice (USEPA 2002a) and in the regulatory determination
(USEPA 2001b) and health effects (USEPA 2003b) support documents for
hexachlorobutadiene.
D. Manganese
Description: Manganese (CASRN 7439-96-5) is a naturally occurring
element found at low levels in soil, water, and food. It is an
essential trace element for humans and all animal species. It
constitutes approximately 0.1
[[Page 42904]]
percent of the earth's crust, however, it does not occur in the
environment in its pure metal form, but is ubiquitous as a component of
more than 100 minerals including many silicates, carbonates, sulfides,
oxides, phosphates, and borates (ATSDR 2000).
Manganese is generally considered to have low toxicity when
ingested orally. The major source of manganese intake in humans (with
the exception of possible occupational exposure) is dietary ingestion;
manganese is a nutrient and is not considered to be very toxic when
ingested with food. Reports of adverse effects following oral exposure
are rare.
Agency Findings: After reviewing the best available public health
and occurrence information, EPA has made the determination not to
regulate manganese with a NPDWR at this time, because it would not
present a meaningful opportunity for health risk reduction for persons
served by PWSs. Manganese is generally not considered to be very toxic
when ingested with the diet and drinking water accounts for a
relatively small proportion of manganese intake.
A complete review of EPA's analysis of the health effects,
occurrence, and exposure for manganese were presented in the June 2002
notice (USEPA 2002a) and in the regulatory determination (USEPA 2001c)
and health effects (USEPA 2003c) support documents for manganese. EPA
is developing a Drinking Water Advisory for manganese to provide
guidance to communities that might be exposed to elevated
concentrations of manganese in their drinking water.
E. Metribuzin
Description: Metribuzin (CASRN 21087-64-9) is a pesticide that does
not volatilize readily, yet is relatively soluble in water. It is
relatively persistent in the environment and degrades primarily through
exposure to sunlight. Metribuzin is used as an herbicide on soybeans,
potatoes, alfalfa, sugar cane, lentils, asparagus, tomatoes, carrots,
peas, barley, wheat, range grasses, and Christmas trees. Metribuzin has
limited non-agricultural utility. Metribuzin is not classifiable as a
human carcinogen, but there may be effects on the liver and body weight
from chronic exposure to high doses.
Agency Findings: After reviewing the best available public health
and occurrence information, EPA has made the determination not to
regulate metribuzin with a NPDWR at this time, because it would not
present a meaningful opportunity for health risk reduction for persons
served by PWSs. Metribuzin is not known to occur in PWSs at levels of
public health concern. National monitoring data indicate that
metribuzin is infrequently detected in public water supplies.
A complete review of EPA's analysis of the health effects,
occurrence, and exposure for metribuzin were presented in the June 2002
notice (USEPA 2002a) and in the regulatory determination (USEPA 2001d)
and health effects (USEPA 2003d) support documents for metribuzin.
F. Naphthalene
Description: Naphthalene (CASRN 91-20-3) is a VOC that is naturally
present in fossil fuels, such as petroleum and coal, and is formed when
wood or tobacco are burned. Naphthalene is produced in commercial
quantities from either coal tar or petroleum. Most naphthalene use
(60%) is as an intermediary in the production of phthalate
plasticizers, resins, phthaleins, dyes, pharmaceuticals, and insect
repellents. Crystalline naphthalene is used as a moth repellent and as
a solid block deodorizer for diaper pails and toilets.
The major source of human exposure to naphthalene is through the
use of moth-balls containing naphthalene. This exposure can be from
breathing the vapors or handling the mothballs. People also may be
exposed by breathing tobacco smoke and air near industries that use or
produce naphthalene. Usually naphthalene is not found in water because
it evaporates or biodegrades quickly. When it is found in water, it is
usually at levels lower than 0.01 mg/L (ATSDR 1995).
Agency Findings: After reviewing the best available public health
and occurrence information, EPA has made the determination not to
regulate naphthalene with a NPDWR at this time, because it would not
present a meaningful opportunity for health risk reduction for persons
served by PWSs. Naphthalene is not known to occur in PWSs at levels of
public health concern. National monitoring data indicate that
naphthalene is infrequently detected in public water supplies.
A complete review of EPA's analysis of the health effects,
occurrence, and exposure for naphthalene were presented in the June
2002 notice (USEPA 2002a) and in the regulatory determination (USEPA
2001e) and health effects (USEPA 2003e) support documents for
naphthalene.
G. Sodium
Description: Sodium (CASRN 7440-23-5) is the sixth most abundant
element on earth and is widely distributed in soils, plants, water, and
foods. Ground water typically contains higher concentrations of
minerals including sodium salts than do surface waters. In addition to
naturally occurring sources of sodium, sodium compounds are used in
deicing roads, as water treatment chemicals, and in domestic water
softeners. Sewage effluents can also contribute significant quantities
of sodium to water.
Sodium is an essential trace element, and adequate levels of sodium
are required for good health. Food is the main source of daily human
exposure to sodium, primarily in the form of sodium chloride (table
salt). Most of the sodium in our diet is added during food processing
and preparation.
Agency Findings: After reviewing the best available public health
and occurrence information, EPA has made the determination not to
regulate sodium with a NPDWR at this time, because it would not present
a meaningful opportunity for health risk reduction for persons served
by PWSs. The contribution of drinking water to daily sodium intake is
very small when compared to the total dietary intake. Short-term
excursions beyond the benchmark values pose no adverse health risk for
most individuals, including the majority of persons with hypertension.
Sodium in drinking water is a very small contributor to daily dietary
intake and the levels at which sodium intake can contribute to
increasing the blood pressure of individuals with normal blood
pressures are not clearly established. The Agency currently does,
however, require monitoring for sodium at the entry point to the
distribution system and that results be reported annually to public
health officials for surface water systems, and every three years for
ground water systems (as defined in 40 CFR 141.41). The water supplier
must report sodium test results to local and State public health
officials, unless this responsibility is assumed by the State. This
requirement is intended to provide the public health community with
information on sodium levels in drinking water to be used in counseling
patients and is the most direct route for gaining the attention of the
affected population.
A complete review of EPA's analysis of the health effects,
occurrence, and exposure for sodium were presented in the June 2002
notice (USEPA 2002a) as well as in the regulatory determination (USEPA
2001f) support document for sodium. EPA is issuing a final Drinking
Water Advisory for sodium concurrent with today's action (USEPA 2003f).
The sodium advisory provides guidance to
[[Page 42905]]
communities that might be exposed to elevated concentrations of sodium
chloride or other sodium salts in their drinking water. This sodium
advisory also provides appropriate cautions for individuals on low-
sodium or sodium-restricted diets.
H. Sulfate
Description: Sulfate (SO4-2, CASRN 14808-79-
8) exists in a variety of inorganic salts. Sulfate salts such as
sodium, potassium, and magnesium are very water soluble and are often
found in natural waters. Sulfate salts of metals such as barium, iron,
or lead have very low water solubility. Sulfate is found in soil,
sediments, and rocks and occurs in the environment as a result of both
natural processes and human activities. Sulfate compounds are used for
a variety of commercial and industrial purposes.
Sulfate may enter surface or ground water as a result of discharge
or disposal of sulfate-containing wastes. In addition, sulfur oxides
produced during the combustion of fossil fuels are transformed to
sulfuric acid in the atmosphere. Through precipitation (acid rain),
sulfuric acid can enter surface waters, lowering the pH and raising
sulfate levels.
Sulfate is present in the diet. A number of food additives are
sulfate salts and most (such as copper sulfate and zinc sulfate) are
approved for use as nutritional supplements.
Sulfate may have adverse health affects on persons, primarily
through its laxative effect following high-level, acute exposures. The
adverse health effect from ingesting high levels of sulfate is
increased water in the fecal matter (diarrhea), possibly contributing
to dehydration. Because local populations usually acclimate to high
sulfate levels, the impact is primarily on infants, transient
populations (e.g., business travelers, visitors, and vacationers), and
new residents.
Agency Finding: After reviewing the best available public health
and occurrence information, EPA has made the determination not to
regulate sulfate with a NPDWR at this time, because it would not
present a meaningful opportunity for health risk reduction for persons
served by PWSs. Although sulfate occurs in many PWSs nationally, the
weight of evidence suggests that the adverse health effect is generally
mild, of short duration, and generally occurs at concentrations
considerably greater than 500 mg/L, except in very limited
circumstances when sulfate co-occurs with magnesium and high total
dissolved solids, which exacerbate its laxative effects. EPA is issuing
a final Drinking Water Advisory to provide guidance to communities that
may be exposed to drinking water with high sulfate concentrations.
A complete review of EPA's analysis of the health effects,
occurrence, and exposure for sulfate were presented in the June 2002
notice (USEPA 2002a) as well as in the regulatory determination (USEPA
2001g) support document for sulfate. EPA will issue a final Drinking
Water Advisory for sulfate concurrent with today's action (USEPA
2003g). The advisory for sulfate provides guidance to communities that
may be exposed to drinking water contaminated with high sulfate
concentrations. This advisory contains information of use to sensitive
sub-populations, such as infants and travelers.
VI. How Will EPA Address the Data Needs of the Remaining 51 CCL
Contaminants?
The Agency continues to conduct research and/or to collect
occurrence information on the remaining CCL contaminants. EPA has been
conducting research to fill identified data gaps. The Agency will take
action as appropriate when information becomes available and will not
necessarily wait until the end of the next regulatory determination
cycle before making other regulatory determinations.
To support decisions on CCL contaminants, the Agency is required to
evaluate when and where these contaminants occur, the extent of
exposure, and their risk to public health. EPA must also determine if
regulating the contaminant presents a meaningful opportunity for
reducing public health risk. Contaminants deemed ready for regulatory
determination, which include those that are the subject of today's
decisions, are determined to have sufficient data to support a decision
as to whether or not to regulate based on evaluation of both exposure
and risk to public health.
The remaining 51 CCL contaminants for which decisions are not being
made today do not have sufficient data to support regulatory decisions.
The Agency continues to conduct research and/or collect occurrence
information on these remaining contaminants. The research issues are
broader than those that EPA can address alone. It is anticipated that
other entities will be involved in conducting much of the needed
research to support this process. EPA continues to identify and develop
new collaborations to conduct research and gather the additional data
to characterize occurrence and adverse health effects to support future
regulatory determinations of CCL contaminants. EPA is also engaged with
our stakeholders in a NDWAC work group to refine the CCL listing
process to address emerging contaminants for future efforts
EPA is committed to providing a means for our stakeholders to track
progress of research on remaining CCL contaminants. The Agency is
currently developing a web-based system that will be available to the
public in 2003. This website will serve as a repository of information
on drinking water research projects currently funded or performed by
EPA.
VII. References
ATSDR, 1993. Toxicological Profile for Aldrin/Dieldrin (Update).
Atlanta, Georgia. U.S. Department of Health and Human Services,
Public Health Service. 184 pp.
ATSDR, 1995. Toxicological Profile for Naphthalene (Update).
Atlanta, Georgia. U.S. Department of Health and Human Services,
Public Health Service. 200 pp.
ATSDR, 2000. Toxicological Profile for Manganese (Update). Atlanta,
Georgia. U.S. Department of Health and Human Services, Public Health
Service. 466 pp. and Appendices.
USEPA, 1997. Announcement of the Draft Drinking Water Contaminant
Candidate List; Notice. Federal Register. Vol. 62, No. 193, p.
52193, October 6, 1997.
USEPA, 1998. Announcement of the Draft Drinking Water Contaminant
Candidate List; Notice. Federal Register. Vol. 63, No. 40, p. 10273,
March 2, 1998.
USEPA, 2000. Methodology for Deriving Ambient Water Quality Criteria
for the Protection of Human Health (2000). EPA-822-B-00-004. October
2000.
USEPA, 2001a. Regulatory Determination Support Document for Aldrin
and Dieldrin. EPA 815 R-01-011.
USEPA, 2001b. Regulatory Determination Support Document for
Hexachlorobutadiene. EPA 815 R-01-009.
USEPA, 2001c. Regulatory Determination Support Document for
Manganese. EPA 815 R-01-013.
USEPA, 2001d. Regulatory Determination Support Document for
Metribuzin. EPA 815 R-01-010.
USEPA, 2001e. Regulatory Determination Support Document for
Naphthalene. EPA 815 R-01-008.
USEPA, 2001f. Regulatory Determination Support Document for Sodium.
EPA 815 R-01-014.
USEPA, 2001g. Regulatory Determination Support Document for Sulfate.
EPA 815 R-01-015.
USEPA, 2002a. Announcement of Preliminary Regulatory Determinations
for Priority Contaminants on the Drinking Water Contaminant
Candidate List. Federal Register. Vol. 67, No. 106, p. 38222, June
3, 2002.
USEPA, 2002b. Fact Sheet: Announcement of Preliminary Regulatory
Determinations for Priority Contaminants on the
[[Page 42906]]
Drinking Water Contaminant Candidate List. EPA 815-F-02-003.
USEPA, 2003a. Health Effects Support Document for Aldrin and
Dieldrin. EPA 822 R-03-001.
USEPA, 2003b. Health Effects Support Document for
Hexachlorobutadiene. EPA 822 R-03-002.
USEPA, 2003c. Health Effects Support Document for Manganese. EPA 822
R-03-003.
USEPA, 2003d. Health Effects Support Document for Metribuzin. EPA
822 R-03-004.
USEPA, 2003e. Health Effects Support Document for Naphthalene. EPA
822 R-03-005.
USEPA, 2003f. Drinking Water Advisory: Consumer Acceptability Advice
and Health Effects Analysis on Sodium. EPA 822 R-03-006.
USEPA, 2003g. Drinking Water Advisory: Consumer Acceptability Advice
and Health Effects Analysis on Sulfate. EPA 822 R-03-007.
USEPA, 2003h. Health Effects Support Document for Acanthamoeba. EPA
822 R-03-012.
Dated: July 11, 2003.
Linda J. Fisher,
Acting Administrator.
[FR Doc. 03-18151 Filed 7-17-03; 8:45 am]
BILLING CODE 6560-50-P
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