Proposed Category for Persistent, Bioaccumulative, and Toxic
Chemical Substances
[Federal Register: October 5, 1998 (Volume 63, Number 192)]
[Notices]
[Page 53417-53423]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05oc98-67]
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ENVIRONMENTAL PROTECTION AGENCY
[OPPTS-53171; FRL-5771-6]
Proposed Category for Persistent, Bioaccumulative, and Toxic
Chemical Substances
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice.
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SUMMARY: EPA has grouped new chemical substances with similar
structural and toxicological properties into working categories. These
groupings enable the Toxic Substances Control Act (TSCA) section
5(a)(1), Premanufacture Notice (PMN) submitters, and EPA reviewers to
benefit from accumulated data and decisional precedents. The
establishment of over 45 of these chemical categories has streamlined
the process for Agency review of and regulatory follow-up on new
chemical substances. Consistent with TSCA section 26(c), which allows
EPA action under TSCA with respect to categories of chemical substances
or mixtures, EPA is developing a category of persistent,
bioaccumulative, and toxic (PBT) chemical substances. This notice
solicits comments on proposed criteria for identifying PBT chemical
substances and their supporting scientific rationale.
[[Page 53418]]
DATES: Written comments should be received on or before December 4,
1998.
ADDRESSES: Comments may be submitted by regular mail, electronically,
or in person. Please follow the detailed instructions for each method
as provided in Unit I. of this document.
FOR FURTHER INFORMATION CONTACT: Susan B. Hazen, Director,
Environmental Assistance Division (7408), Rm. E-531, Office of
Pollution Prevention and Toxics, Environmental Protection Agency, 401 M
St., SW., Washington, DC 20460, telephone: (202) 554-1404, TDD: (202)
554-0551; e-mail: TSCA-Hotline@epa.gov.
SUPPLEMENTARY INFORMATION:
I. General Information
A. Does this notice apply to me?
You may be potentially affected by this notice if you are or may in
the future be a submitter of a Premanufacture Notice (PMN) under TSCA.
Potentially affected categories and entities may include, but are not
limited to:
------------------------------------------------------------------------
Examples of Potentially
Category Affected Entities
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Chemical manufacturers or importers Anyone who plans to
manufacture or import a new
chemical substance for a
non-exempt commercial
purpose is required to
provide the EPA with a PMN
at least 90 days prior to
the activity. Any substance
that is not on the TSCA
Inventory is classified as
a new chemical.
------------------------------------------------------------------------
This table is not intended to be exhaustive, but rather provides a
guide for readers regarding entities likely to be affected by this
action. Other types of entities not listed in this table could also be
affected. To determine whether you or your business is affected by this
action, you should carefully examine the applicability provisions in 40
CFR 720.22. If you have any questions regarding the applicability of
this action to a particular entity, consult the technical person listed
in the ``FOR FURTHER INFORMATION CONTACT'' section.
B. How can I get additional information or copies of support documents?
1. Electronically. Electronic copies of this document are available
from the EPA Home page at the Federal Register-Environmental Documents
entry for this document under ``Laws and Regulations'' (http://
www.epa.gov/fedrgstr/).
2. In person. The official record for this notice, as well as the
public version, has been established under docket control number OPPTS-
53171 (including comments and data submitted electronically as
described in Unit I.C.3. of this preamble). A public version of this
record, including printed, paper versions of any electronic comments,
which does not include any information claimed as Confidential Business
Information (CBI), is available for inspection from 12 noon to 4 p.m.,
Monday through Friday, excluding legal holidays. The official record is
located in the TSCA Nonconfidential Information Center, Rm. NE-B607,
401 M St., SW., Washington, DC.
C. How and to whom do I submit comments?
All comments must be identified by the docket control number OPPTS-
53171. You may submit comments through the mail, in person, or
electronically:
1. By mail. Submit written comments to: Document Control Office
(7407), Office of Pollution Prevention and Toxics (OPPT), Environmental
Protection Agency, 401 M St., SW., Rm. G-099, East Tower, Washington,
DC 20460. The Document Control Office telephone number is (202) 260-
7093.
2. In person. Deliver written comments to: Document Control Office
in Rm. G-099, East Tower, Waterside Mall, 401 M St., SW., Washington,
DC.
3. Electronically. Submit your comments and/or data electronically
to: oppt.ncic@epa.gov. Please note that you should not submit any
information electronically that you consider to be CBI. Electronic
comments must be submitted as an ASCII file avoiding the use of special
characters and any form of encryption. Comment and data will also be
accepted on disks in Wordperfect 5.1/6.1 or ASCII file format.
Electronic comments on this notice may also be filed online at many
Federal Depository Libraries.
D. How should I handle information that I believe is confidential?
You may claim information that you submit in response to this
document as confidential by marking any part or all of that information
as CBI. Information so marked will not be disclosed except in
accordance with procedures set forth in 40 CFR part 2. A copy of the
comment that does not contain CBI must be submitted for inclusion in
the public record. Information not marked confidential will be included
in the public docket by EPA without prior notice.
II. New Chemicals Program
A. Overview of the PMN Process
Under section 5(a) of TSCA, persons must notify EPA at least 90
days before manufacturing or importing a new chemical substance for
non-exempt purposes. A new chemical substance, as defined in section
3(9) of TSCA, is any chemical that is not included on the Inventory
compiled under section 8(b) of TSCA.
Section 5 of TSCA gives EPA 90 days to review a PMN. However, the
review period can be extended under TSCA section 5(c) for ``good
cause''; it may also be suspended voluntarily by the mutual consent of
EPA and the PMN submitter. During the review period, EPA may take
action under TSCA section 5(e) or (f) to prohibit or limit the
production, processing, distribution in commerce, use, and disposal of
new chemical substances that raise health or environmental concerns. If
EPA has not taken action under TSCA section 5(e) or (f), the PMN
submitter may manufacture or import the new chemical substance when the
review period expires.
No later than 30 days after the PMN submitter initiates
manufacturing or importing, it must provide EPA with a notice of
commencement of manufacture or import. Section 8(b) of TSCA provides
that, upon receipt of such a notice, EPA must add the substance to the
TSCA Inventory. Thereafter, other manufacturers and importers may
engage in activities involving the new substance without submitting a
PMN.
B. Actions under TSCA Sections 5(e) and (f)
Section 5(e) of TSCA authorizes EPA to control commercial
activities involving a new chemical substance for which available
information is insufficient to permit a reasoned evaluation of
potential health and environmental effects if EPA determines either
that:
1. The manufacture (including import), processing, distribution in
commerce, use, or disposal of the substance may present an unreasonable
risk of injury to health or the environment (``risk-based'' finding,
under TSCA section 5(e)(1)(A)(ii)(I)).
2. The substance is or will be produced in substantial quantities,
and such substance either enters or may reasonably be anticipated to
enter the environment in substantial quantities or there is or may be
significant or substantial human exposure to the
[[Page 53419]]
substance (``exposure-based'' finding, under TSCA section
5(e)(1)(A)(ii)(II)).
The restrictions under TSCA section 5(e) are imposed pending the
development of the test data or other information needed to evaluate
the new substance's health or environmental effects.
Section 5(f) of TSCA authorizes EPA to take action where it finds
that there is a reasonable basis to conclude that the activities
involving a new chemical substance will present an unreasonable risk of
injury to health or the environment. If EPA makes such a determination,
it may prohibit or limit manufacture (including import), distribution
in commerce, processing, use, and disposal of the new substance to
protect against the unreasonable risk.
C. EPA's Strategy under TSCA Section 5(e)
On occasion, EPA may have concerns about a new chemical substance
based on test data included in the PMN or obtained from other sources.
However, because test data on PMN chemical substances are not required,
EPA typically receives few PMNs that contain sufficient data on health
or environmental effects, or on the potential to persist or
bioaccumulate in the environment. As a result, the Agency often relies
on computer models and structural or functional analogues as indicators
of the potential toxicity and environmental fate of a PMN chemical
substance.
Due to the generally limited test data that are submitted or are
otherwise available on a new chemical substance, EPA often identifies
the substance for TSCA section 5(e) action because it is similar in
molecular structure or function to other chemical substances known or
suspected to have adverse health or environmental effects. These
predictive methods, which estimate the properties of a chemical, e.g.,
melting point, vapor pressure, toxicity and ecotoxicity, on the basis
of its structure, are referred to as Structure-Activity Relationships
(SAR). A joint US/European Union (EU) study evaluated the predictive
power of the SAR by applying SAR methods to chemical substances for
which ``base set'' test data were already available and then comparing
the properties predicted by SAR with the properties observed in
laboratory testing. The available test data were part of a minimum pre-
market data set (MPD) submitted on chemical substances in the context
of the notification scheme established in the EU. Analysis of the
results of this study showed that while this SAR approach was largely
successful in identifying chemical substances of concern, the process
could be improved by selectively incorporating specific testing schemes
into the process (USEPA, 1994, see Unit IV.1. of this preamble).
As indicated in Unit II.B., during PMN review, EPA may determine
that the available information is insufficient to permit a reasoned
evaluation of the new chemical substance that is the subject of the
PMN. At the same time, EPA may determine, under TSCA section
5(e)(1)(A)(ii)(I), based on SAR analysis that activities involving the
new substance ``may present an unreasonable risk of injury to health or
the environment.'' When EPA makes both of these two findings, it acts
under TSCA section 5(e) to regulate the activities involving the new
substance which contribute to the potential risk. The new chemicals
program determines the effectiveness of environmental release controls,
consistency with existing chemical regulatory activity in the Agency,
and the affordability of certain testing, etc. in formulating the
appropriate regulatory response for each new chemical. In cases where a
potential hazard is identified, EPA believes that it is appropriate to
negotiate an order (known as a ``consent order'') under TSCA section
5(e) with the PMN submitter to control human exposure and/or
environmental releases until test data or other information sufficient
to assess adequately the potential risk become available. Section 5(e)
of TSCA ``risk-based'' consent orders have specified a variety of
control measures, including protective equipment, use limitations,
process restrictions, labeling requirements, and limits on
environmental release. Some recent consent orders have included testing
requirements that are triggered when specified levels of production
volume or other indices of increased exposure are reached; under these
orders, the submitter may not exceed the production volume limitation
or any other restriction imposed by EPA until test data specified by
EPA have been submitted to and reviewed by EPA.
In other instances, during PMN review EPA may determine under TSCA
section 5(e)(1)(A) (ii)(II) that a new substance will be produced in
substantial quantities and ``may reasonably be anticipated to enter the
environment in substantial quantities or there is or may be significant
or substantial human exposure to the substance,'' and that the
available information is insufficient to determine the effects of the
substance. Since 1988, EPA has used internally developed guidelines to
assist in identifying new chemical substances received as PMNs which
would meet the TSCA section 5(e)(1)(A)(ii)(II) exposure-based finding
(USEPA, 1988 and 1989, see Unit IV.2. and 3. of this preamble). Data
received as a result of EPA's implementation of this exposure-based
policy via TSCA section 5(e) consent orders have been used by EPA to
better characterize the fate and effects of the new chemical, confirm
or refute a prediction of low risk, and supplement and validate the use
of SAR in the review of PMNs. These exposure-based guidelines capture
all PMN chemical substances with estimated production volumes greater
than or equal to 100,000 kilograms (kg) per year and exceeding specific
exposure/release criteria. In some cases, however, where these
thresholds are not met, it may be more appropriate to use a case-by-
case approach for making findings by applying other considerations
(i.e., toxicity or physical/chemical properties). For reasons that have
been articulated in the proposed statement of policy for TSCA section
4(a)(1)(B) (July 15, 1991, 56 FR 32294), where persistence and
bioaccumulation were used as examples, EPA may consider additional
factors for making findings for substances which do not meet the
numerical thresholds for evaluating new chemical substances under TSCA
section 5(e)(1)(A)(ii)(II). Conversely, EPA may not take action under
this TSCA section 5(e)(1)(A)(ii)(II) policy when the chemical substance
meets the proposed criteria if EPA finds that existing data are
sufficient to evaluate health or environmental effects of the new
chemical substance, or that regulation and the development of
information is not otherwise necessary.
Exposure-based consent orders issued to address concerns under TSCA
section 5(e)(1)(A)(ii)(II) include testing requirements, record keeping
provisions, and production volume limits. The proposed PBT category
criteria would impact EPA's development of both risk-based and
exposure-based TSCA section 5(e) consent orders for new PBT chemical
substances.
D. EPA's Use of Chemical Substance Categories in PMN Review and in
Regulatory Decision Making under TSCA Section 5(e)
In 1987, EPA grouped chemical substances with similar
physicochemical, structural, and toxicological properties into working
categories. Candidate categories for the new chemicals review process,
such as the category being proposed today for PBT chemical substances,
are proposed by new chemicals program staff based
[[Page 53420]]
on available data and experience reviewing PMNs on related substances.
These groupings enable both PMN submitters and EPA reviewers to benefit
from the accumulated data and decisional precedents. The first category
defined by SAR was ``acrylates and methacrylates.'' Currently, there
are over 45 categories, the detailed summaries of which can be found on
the Internet at http://www.epa.gov/opptintr/newchms/chemcat.htm.
The establishment of these categories has streamlined the process
for Agency review of new chemical substances. As it gained experience
with reviews of chemical substances in categories, EPA moved certain
decisions for the category chemical substances to points much earlier
in the 90-day PMN review period. One such point is the Focus Meeting,
where exposure and hazard information about a PMN substance is first
brought together for a risk management decision. If, for example, a new
substance is identified as being a member of the proposed PBT chemical
substances category, the chemical would be evaluated in the context of
the potential health or environmental concerns associated with that
category.
The Agency recommends that regulatory action be taken under TSCA
section 5(e) to control potential risks to health or the environment on
about 10 percent of the approximately 2,000 PMNs submitted yearly. Only
2-3 percent of the total number of PMNs submitted (20-30 percent of the
above 10 percent) now undergo a detailed review that takes most of the
standard 90-day PMN period, while the remaining 7-8 percent are
identified for expedited review by virtue of them being members of the
new chemicals program chemical categories. In response to pending
regulatory action by the Agency, half of this 10 percent total are
voluntarily withdrawn by PMN submitters.
E. New Chemical Significant New Use Rules (SNURs)
TSCA section 5(e) consent orders (as described in Unit II.C.) apply
only to PMN submitters. When a PMN submitter commences commercial
manufacture of the substance and submits a Notice of Commencement of
Manufacture to EPA, EPA adds the substance to the TSCA Chemical
Substance Inventory maintained pursuant to section 8(b) of TSCA. When a
substance is listed on the Inventory, it is no longer a ``new chemical
substance'' for which a PMN would be required. Thus, other persons
would be able to manufacture, import, or process the substance without
EPA review and without the restrictions imposed on the PMN submitter by
the TSCA section 5(e) consent order.
In addition to consent orders issued under section 5(e) of TSCA
regulating the PMN submitter, EPA uses its Significant New Use Rule
(SNUR) authority under TSCA section 5(a)(2) to extend limitations in
TSCA section 5(e) consent orders to other manufacturers, importers, and
processors of the PMN substance. Section 5(a)(2) of TSCA (15 U.S.C.
2604(a)(2)) authorizes EPA to determine that a use of a chemical
substance is a ``significant new use.'' EPA must make this
determination in a SNUR after considering relevant information about
the toxicity of the substance and the 4 factors listed in section
5(a)(2) of TSCA (projected production volume, the extent to which a use
changes the type or form of exposure to the chemical substance, the
extent to which a use changes the magnitude and duration of exposure to
the chemical substance, and the reasonably anticipated manner and
methods of manufacturing, processing, distribution in commerce, and
disposal of the chemical substance). EPA designates the significant new
uses of each chemical substance based on these considerations. Once EPA
determines that a use of a chemical substance is a significant new use,
section 5(a)(1)(B) of TSCA requires persons to submit a notice to EPA
at least 90 days before they manufacture, import, or process the
substance for that use. The required notice provides EPA with the
opportunity to evaluate the intended use, and if necessary, to prohibit
or limit that activity before it occurs.
EPA's use of its SNUR authority ensures that the original PMN
submitters and subsequent manufacturers, importers, and processors are
treated in an equivalent manner. These SNURs are framed so that non-
compliance with the control measures or other restrictions in the TSCA
section 5(e) consent orders is defined as a ``significant new use.''
Thus, other manufacturers, importers, and processors of the substances
must either observe the SNUR restrictions or submit a significant new
use notice to EPA at least 90 days before initiating activities that
deviate from these restrictions. After receiving and reviewing such a
notice, EPA has the option of either permitting the new use or acting
to regulate the new submitter's activities.
EPA also reviews some new chemical substances that do not warrant
direct regulation of the PMN submitter under TSCA section 5(e) but
merit other follow-up monitoring and evaluation. On the basis of test
data or SAR analysis, EPA may identify potential health or
environmental effects that could create a basis for concern if the
substances exposure or release potential later changes or increases
beyond that described in the PMN. In most of these cases, EPA believes
it is appropriate to use SNUR authority to monitor the commercial
development of these substances so that EPA can be apprised of
significant increases in exposure potential, which may warrant control
measures or testing.
In addition to ensuring that all manufacturers, importers, and
processors are subject to similar reporting requirements and
restrictions, SNURs have the following additional objectives:
1. EPA will receive notice of any company's intent to manufacture,
import, or process a chemical substance listed on the TSCA Inventory
for a significant new use before that activity begins.
2. EPA will have an opportunity to review and evaluate data
submitted in a SNUR notice before the notice submitter begins
manufacturing, importing, or processing a listed chemical substance for
a significant new use.
3. When necessary, EPA will be able to take regulatory action under
TSCA section 5(e), 5(f), 6, or 7 to control the activities for which it
received a SNUR notice before a significant new use of that substance
occurs.
III. EPA's PBT Chemical Substances Initiative
A. Background
PBT chemical substances possess characteristics of persistence (P)
in the environment, accumulation in biological organisms
(bioaccumulation (B)), and toxicity (T) that make them priority
pollutants and potential risks to humans and ecosystems. Prominent
examples of PBT chemical substances include DDT and polychlorinated
biphenyls (PCBs). Consistent with TSCA section 26(c), which allows EPA
action under TSCA with respect to categories of chemical substances or
mixtures, EPA is developing a category of persistent, bioaccumulative,
and toxic (PBT) chemical substances. The category being proposed is for
the purposes of facilitating the assessment of new chemical substances
under TSCA section 5(e) prior to their entry into the marketplace.
The proposed category description draws upon ongoing international
efforts (e.g., the U.S.-Canada Binational Strategy for virtual
elimination of PBTs; the North American Free Trade
[[Page 53421]]
Agreement (NAFTA) Commission for Environmental Cooperation negotiations
on Persistent Organic Pollutants (POPs); the United Nations Economic
Commission for Europe (UNECE) convention on Long-Range Transboundary
Air Pollution (LRTAP); and the POPs Initiative under the United Nations
Environment Programme (UNEP)) as well as Agency efforts (e.g., the
Waste Minimization Prioritization Tool (WMPT)) to craft a coordinated
and scientifically supportable approach to identifying PBT chemical
substances. In particular, the proposed category is viewed by the
Agency as furthering the objectives of UNECE's convention on LRTAP,
Article 7, paragraphs 2 (b) and (c), which state that ``Each Party
shall....encourage the implementation of other management programmes to
reduce emissions of persistent organic pollutants'' and ``consider the
adoption of additional policies and measures as appropriate in its
particular circumstances'' (UNECE-LTRAP, 1998, see Unit IV.4. of this
preamble).
The proposed PBT category reflects the exchange of information
across offices within EPA and results, in part, from the opportunity
for programs to collaborate and complement each other's work. The
category statement includes the boundary conditions, such as fish
bioconcentration/bioaccumulation factors and environmental persistence
values, that would determine inclusion in (or exclusion from) the
category, and standard hazard and fate tests to address P, B, and T
concerns for the chemical substances fitting the category description.
It should be noted that the Agency is separately considering lower
manufacture, processing, and ``otherwise use'' reporting thresholds for
PBT chemical substances subject to reporting under the Emergency
Planning and Community Right-To-Know Act (42 U.S.C. 11023), section 313
or Toxic Chemical Release Inventory (TRI) program. Rather than rely
exclusively on statutorily separate, single-medium approaches to
address these pollutants, an Agency-wide PBT Strategy is presently
being developed and implemented. The PBT Strategy coordinates the
efforts being made by various EPA offices on PBT chemical substances
and directs them in a targeted fashion to chemical substances that may
present the greatest health and environmental risks. Establishment of
this category would thus provide a vehicle by which the Agency may
gauge the flow of PBT chemical substances through the TSCA new
chemicals program and measure the results of its risk screening and
risk management activities for new chemical members of this category of
chemical substances as one component in the Agency's overall PBT
initiative.
B. Proposed Evaluation Criteria and Process for PBT Chemical Substances
Generally, persistent bioaccumulators are chemical substances that
partition to water, sediment, or soil and are not removed at rates
adequate to prevent their bioaccumulation in aquatic or terrestrial
species (Veith et al., 1979, see Unit IV.5. of this preamble). EPA is
proposing the following specific identification criteria and associated
process for use in evaluating new chemical substances.
New Chemicals Program PBT Category Criteria and Process
------------------------------------------------------------------------
TSCA Section 5 Action
---------------------------------------
5(e) Order/
Significant New Ban Pending
Use Rule (SNUR)<SUP>1 Testing<SUP>2
------------------------------------------------------------------------
Persistence (transformation half- > 2 months........ > 6 months
life).
Bioaccumulation (Fish BCF or <gr-thn-eq> 1000.. <gr-thn-eq> 5000
BAF)<SUP>3.
Toxicity........................ Develop toxicity Develop toxicity
data where data where
necessary<SUP>4. necessary<SUP>4
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<SUP>1Exposure/release controls included in order; testing required.
<SUP>2Deny commercialization; testing results may justify removing chemical
from ``high risk concern''.
<SUP>3Chemicals must also meet criteria for MW (< 1000) and cross-sectional
diameter (< 20A , or < 20 x 10<SUP>-8 cm).
<SUP>4Based upon various factors, including concerns for P, B, other physical/
chemical factors, and predicted toxicity.
The half-life/persistence criterion for aquatic environments of > 2
months is the same as that proposed under the UNECE-LRTAP negotiations
(UNECE-LRTAP, 1997, see Unit IV.6. of this preamble). It represents a
chronic exposure to aquatic organisms, as well as approximating the
duration of some standard bioconcentration (28-56 days) and chronic
toxicity (14-90 days) tests, and is therefore thought to be adequate
for detecting many long-term toxic effects as well as any tendency for
a substance to accumulate in fatty tissue of aquatic organisms. The
bioconcentration or bioaccumulation factor (BCF/BAF) measures the
potential for a chemical to accumulate in living organisms relative to
its concentration in the surrounding environment. BCF/BAF is estimated
using calculations based on octanol-water partition coefficients (Kow),
although data can also be provided from field or laboratory
measurements (Spacie et al., 1995, see Unit IV.7. of this preamble).
Chemical substances having a BCF or BAF > 1000 are characterized by a
tendency to accumulate in organisms (Smrchek et al., 1998, Zeeman,
1995, Smrchek et al., 1993, see Unit IV.8., 9., and 10. of this
preamble). The relationship between BCF/BAF and log Kow, which is a
complex one above log Kow = 7, is discussed by several authors (Fisk et
al., 1998, Bintein et al., 1993, Gobas et al., 1989, Mackay et al.,
1996, see Unit IV.11., 12., 13., and 14. of this preamble).
Chemical substances meeting the persistence criterion of > 6 months
and the bioaccumulation criterion of <gr-thn-eq> 5000 have properties
consistent with substances widely acknowledged to be persistent,
bioaccumulative, and toxic (e.g., DDT, PCBs, and other chemical
substances identified as persistent organic pollutants during
negotiations on LRTAP) and, as such, are accorded an appropriate level
of concern. Other support for this higher tier can be found in the
Chemical Manufacturers Association's (CMA's) product risk management
guidance for PBT chemical substances (Chemical Manufacturers
Association, 1996, see Unit IV.15. of this preamble). This guidance,
which underscores CMA's commitment to the principles of the industry's
Responsible Care<Register> initiative, cites these P and B criteria as
benchmarks in the screening process for PBT chemical substances.
Releases to all environmental media, such as air emissions from
stacks, wastes disposed of in landfills or on land, and waste
discharged into water, will be factored into the Agency's determination
of potential risk posed by a given PMN chemical substance's total
environmental load. In making this determination of potential risk the
Agency may employ multimedia fate models, such as the Environmental
Quality Criteria (EQC) model (Mackay, 1982, see Unit IV.16. of this
preamble), in order to account for all potential sources and loadings,
environmental transformation processes, and intermedia partitioning, in
an integrated fashion. EPA solicits comments on this approach.
Chemical substances characterized as suspected persistent
bioaccumulators may need to undergo testing on ``P'' and ``B''
endpoints which, if confirmed, would be followed by appropriate
[[Page 53422]]
toxicity testing to identify ``PBT chemical substances.'' Control
action under TSCA section 5(e) may be needed in varying degrees, based
upon level of risk concern. The ``ban'' criteria are equivalent to
those that have been used internationally to identify PBT substances.
Agency control actions taken under TSCA section 5(e) for chemical
substances meeting these criteria would be based upon the level of
certainty for the PBT properties of a PMN substance (e.g., measured vs.
estimated values), the magnitude of Agency concerns, and conditions of
expected use and release of the chemical. For example, new chemical
substances meeting the PBT criteria listed under ``TSCA Section 5(e)
Consent Order/Significant New Use Rule (SNUR)'' could be addressed via
a negotiated consent agreement under which necessary testing is
``triggered'' by specific production limits. While the PMN submitter
would be allowed to commercialize the substance, certain controls could
be stipulated, including annual TRI-type reporting on environmental
releases of the PMN substance and specific limits on exposures,
releases, or uses. For the chemical substances meeting the criteria
listed under ``Ban Pending Testing,'' the concern level is higher and
the Agency would look carefully at any and all environmental releases.
Because of the increased concern, more stringent control action would
be a likely outcome, up to a ban on commercial production until data
are submitted which allow the Agency to determine that the level of
risk can be appropriately addressed by less restrictive measures. The
described control actions represent just one body of possible decisions
and should not be considered as exclusive of other risk management
options.
C. Testing Strategy for PBT Chemical Substances
Where EPA is unable to adequately determine the potential for
bioaccumulation, persistence in the environment, and toxicity which may
result from exposure of humans and environmental organisms to a
possible PBT chemical substance, the Agency may conclude pursuant to
sections 5(e)(1)(A)(I) and 5(e)(1)(A)(ii)(I) and (II) of TSCA that the
information available to the Agency is insufficient to permit a
reasoned evaluation of the human health and environmental effects of
that PMN substance. The manufacturing, processing, distribution in
commerce, use, or disposal of the substance may present an unreasonable
risk of injury to human health or the environment and/or that the PMN
substance will be produced in substantial quantities and there may be
significant or substantial human exposure to the substance, or the PMN
substance may reasonably be anticipated to enter the environment in
substantial quantities. Accordingly, the Agency may find it appropriate
to prohibit a company from manufacturing, importing, processing,
distributing in commerce, using, or disposing of the PMN substance in
the United States pending the development of information necessary for
a reasoned evaluation of these effects. The following testing strategy
describes test data which, if not otherwise available, EPA believes are
needed to evaluate the potential persistence, bioaccumulation, and
toxicity of a PBT chemical substance for which EPA has made the
described risk and/or exposure-based findings under section
5(e)(1)(A)(I) and (ii) of TSCA. The tests are tiered; depending upon
the circumstances, such as magnitude of environmental releases, results
of testing, or SAR, testing could begin above Tier 1 or additional,
higher levels of testing may be required.
Tier 1. If, based upon SAR and professional judgment, the Agency
identifies a new chemical substance as a possible PBT chemical
substance, Log Kow should be determined experimentally, using either
the liquid chromatography (OPPTS 830.7570 test guideline) or generator
column (OPPTS 830.7560 test guideline) method. Ready biodegradability
should be determined according to either one of the following test
guidelines:
1. Ready biodegradability (OPPTS 835.3110 test guideline) 6 methods
(choose one): DOC Die-Away, CO<INF>2</INF> Evolution, Modified MITI
(I), Closed Bottle, Modified OECD Screening, Manometric Respirometry.
2. Sealed-vessel CO<INF>2</INF> production test (OPPTS 835.3120
test guideline).
3. Hydrolysis in water (OPPTS 835.2110 test guideline) should be
determined if, based upon SAR, susceptibility to hydrolysis is
suspected.
If the measured log Kow is < 3.5 or if the test chemical passes
(pass criteria are described in the test guidelines) the ready
biodegradability test (i.e., not persistent in the environment), no
further PBT-related testing is required. If the measured log Kow is
<gr-thn-eq> 3.5, the chemical does not pass the ready biodegradability
test, and no further testing is deemed necessary in tier 1; the
chemical would require tier 2 testing. If hydrolysis testing is
conducted and results in a half-life of < 60 days, further testing may
not be needed, but the need for testing must be determined after
consideration of factors specific to the case, such as physical/
chemical properties, persistence and bioaccumulative qualities of
hydrolysis products, and the nature of the expected releases.
Tier 2. Biodegradability should be determined according to the
Shake-flask die-away test (OPPTS 835.3170 test guideline) or an
equivalent test. This test is based on the principle of aerobic
incubation of the test chemical in natural water with and without
suspended sediment, requires a chemical-specific analytical method, and
allows for the development of a first-order rate constant and half-
life. It provides information on persistence that is relevant to the
natural environment and is intermediate in cost between ready
biodegradability tests (tier 1) and aquatic microcosms (tier 3).
Bioaccumulation potential should be determined by experimental
measurement of the bioconcentration factor (BCF), using the Fish
bioconcentration test (OPPTS 850.1730 test guideline (public draft)).
Measured BCF should be based on 100 percent active ingredient and
measured concentration(s).
If the measured biodegradation half-life is > 60 days and measured
BCF is > 1000, tier 3 testing will be required. If only one condition
is met, releases and exposure are further considered to determine if
additional testing is required.
Tier 3. Toxicity/advanced environmental fate testing. Human health
hazards should be determined in the combined repeated dose oral
toxicity with the reproductive/developmental toxicity screening test
(Organization for Economic Cooperation and Development (OECD) guideline
no. 422) in rats. Other health testing will be considered where
appropriate.
Environmental fate testing should be conducted according to the
Sediment/water microcosm biodegradation test (OPPTS 835.3180 test
guideline). The principle of this method is the determination of the
test chemical's fate, including transport and transformation, in core
chambers containing intact benthic sediment and overlying site water.
The method permits more accurate and reliable extrapolation to natural
aquatic environments than is possible with lower tier test methods.
Chronic toxicity to fish (rainbow trout) and daphnids should be
determined according to 40 CFR 797.1600 and 40 CFR 797.1330,
respectively. Additional testing to evaluate other biota (e.g., avian,
sediment dwelling organisms) or other effects (e.g., endocrine
disrupting
[[Page 53423]]
potential) will be considered where appropriate.
IV. References
The OPPTS harmonized test guidelines referenced in this document
are available on EPA's World Wide Web site (http://www.epa.gov/epahome/
research.htm) under the heading ``Test Methods and Guidelines/OPPTS
Harmonized Test Guidelines.''
1. USEPA. March, 1994. U.S. EPA/EC Joint Project on the Evaluation
of (Quantitative) Structure Activity Relationships. EPA 743-R-94-001.
2. USEPA. 1988. Implementation Proposal; ``New Chemicals Exposure-
Based Finding,'' letter from Charles L. Elkins to Geraldine V. Cox
(Chemical Manufacturers Association). Office of Toxic Substances, USEPA
(September 22, 1988).
3. USEPA. 1989. ``EPA's Exposure-Based Policies under Section 5 of
TSCA,'' letter from Charles L. Elkins to Geraldine V. Cox (Chemical
Manufacturers Association). Office of Toxic Substances, USEPA (August
31, 1989).
4. UNECE-LRTAP. 1998. Draft protocol to the convention on long-
range transboundary air pollution on persistent organic pollutants.
United Nations Economic Commission for Europe. EB.AIR/1998/2; 31 March
1998.
5. Veith, G.D., DeFoe, D.L. and Bergstedt, B.V. 1979. Measuring and
estimating the bioconcentration factor of chemicals in fish. J. Fish.
Res. Board Can. 36:1040-1048.
6. UNECE-LRTAP. 1997. Draft composite negotiating text for a
protocol on persistent organic pollutants. United Nations Economic
Commission for Europe. EB.AIR/WG.5/R.72/Rev.1; 22 July 1997.
7. Spacie, A., McCarty, L.S. and G.M. Rand. 1995. Bioaccumulation
and bioavailability in multiphase systems, pp. 493-521. In, G.M. Rand
(ed.), Fundamentals of Aquatic Toxicology, 2nd. ed. Taylor Francis
Publishers, Washington, DC.
8. Smrchek, J.C. and M.G. Zeeman. 1998. Assessing Risks to
Ecological Systems from Chemicals, pp. 24-90. In, P. Calow (ed.),
Handbook of Environmental Risk Assessment and Management, Blackwell
Science Ltd., Oxford, UK.
9. Zeeman, M.G. 1995. Ecotoxicity Testing and Estimated Methods
Developed Under Section 5 of the Toxic Substances Control Act (TSCA),
pp. 703-715. In, Rand (ed.), Fundamentals of Aquatic Toxicology, 2nd.
ed. Taylor Francis Publishers, Washington, DC.
10. Smrchek, J.C., Clements, R., Morcock, R., and W. Rabert. 1993.
Assessing Ecological Hazard Under TSCA: Methods and Evaluation of Data,
pp. 22-39. In, W.G. Landis, J.S. Hughes, and M.L. Lewis (eds.),
Environmental Toxicology and Risk Assessment, ASTM STP 1179, American
Society for Testing and Materials, Philadelphia, PA.
11. Fisk, A.T., Norstrom, R.J., Cymbalisty, C.D., Muir, D.C.G.
1998. Dietary accumulation and depuration of hydrophobic
organochlorines: bioaccumulation parameters and their relationship with
the octanol/water partition coefficient. Environ. Toxicol. Chem.
17:951-961.
12. Bintein, S., Devillers, J. and Karcher, W. 1993. Nonlinear
dependence of fish bioconcentration on n-octanol/water partition
coefficient. SAR and QSAR in Environ. Research 1:29-39.
13. Gobas, F.A.P.C., Clark, K.E., Shiu, W.Y., Mackay, D. 1989.
Bioconcentration of polybrominated benzenes and biphenyls and related
superhydrophobic chemicals in fish: role of bioavailability and
elimination into the feces. Environ. Toxicol. Chem. 8:231-245.
14. Mackay, D., Di Guardo, A., Paterson, S., Cowan, C.E. 1996.
Evaluating the environmental fate of a variety of types of chemicals
using the EQC model. Environ. Toxicol. Chem. 15:1627-1637.
15. Chemical Manufacturers Association. 1996. PTB Policy
Implementation Guide. Product Risk Management Guidance for PTBs.
Arlington, VA.
16. Mackay, D. 1982. Correlation of bioconcentration factors.
Environ. Sci. Technol. 16:274-278.
List of Subjects
Environmental protection, Chemical, Hazardous substances, Reporting
and recordkeeping requirements
Dated: September 24, 1998.
Lynn R. Goldman,
Assistant Administrator, Office of Prevention, Pesticides and Toxic
Substances.
[FR Doc. 98-26630 Filed 10-5-98; 8:45 am]
BILLING CODE 6560-50-F
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