[Federal Register Volume 64, Number 213 (Thursday, November 4, 1999)]
[Notices]
[Pages 60194-60204]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-28888]
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ENVIRONMENTAL PROTECTION AGENCY
[OPPTS-53171A; FRL-6097-7]
Category for Persistent, Bioaccumulative, and Toxic New Chemical
Substances
AGENCY: Environmental Protection Agency (EPA).
ACTION: Policy statement.
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SUMMARY: EPA groups new chemical substances with similar structural and
toxicological properties into categories to facilitate premanufacture
assessment and regulation. These groupings enable both Toxic Substances
Control Act (TSCA) section 5(a)(1) Premanufacture Notice (PMN)
submitters and EPA reviewers to benefit from accumulated data and
decisional precedents and have 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
issuing this policy statement regarding a category of persistent,
bioaccumulative, and toxic (PBT) new chemical substances.
DATES: This document will become effective January 3, 2000.
FOR FURTHER INFORMATION CONTACT: For general information contact:
Christine Augustyniak, Associate Director, Environmental Assistance
Division (7408), Office of Pollution Prevention and Toxics,
Environmental Protection Agency, 401 M St., SW., Washington, DC 20460;
telephone numbers: 202-554-1404 and TDD: 202-554-0551; e-mail address:
TSCA-H[email protected].
For technical information contact: Kenneth Moss, Chemical Control
Division (7405), Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460; telephone number: 202-260-3395; fax number: 202-
260-0118; e-mail address: [email protected].
SUPPLEMENTARY INFORMATION: On October 5, 1998 (63 FR 53417) (FRL-5571-
6), EPA published a Federal Register notice soliciting comments on
proposed criteria for identifying PBT chemical substances and their
supporting scientific rationale. This policy statement responds to
comments on the proposed criteria for identifying PBT new chemical
substances and their supporting scientific rationale. Please consult
the October 5, 1998 (63 FR 53417) Federal Register notice for further
information on the TSCA new chemicals program. The docket control
[[Page 60195]]
number for this document is OPPTS-53171A.
I. General Information
A. Does This Document Apply to Me?
You may be potentially affected by this document if you are or may
in the future be a submitter of a PMN under TSCA. Potentially affected
entities may include, but are not limited to the following:
----------------------------------------------------------------------------------------------------------------
Examples of Potentially
Category NAICS Code SIC Codes Affected Entities
----------------------------------------------------------------------------------------------------------------
Chemical manufacturers or importers 325, 32411 28, 2911 Anyone who plans to
manufacture or import a
new chemical substance (as
defined in TSCA Section 3)
for a non-exempt
commercial purpose is
required to provide the
EPA with a PMN at least 90
days prior to the
activity. Any TSCA
chemical substance that is
not on the TSCA Inventory
is classified as a new
chemical. New chemical
substances submitted by
chemical manufacturers or
importers as PMNs and
which are determined by
EPA to meet the PBT
criteria described here
may be subject to
regulatory controls under
TSCA section 5(e).
----------------------------------------------------------------------------------------------------------------
This listing is not intended to be exhaustive, but rather provides
a guide for readers regarding entities likely to be affected by this
document. Other types of entities not listed above could also be
affected. The four-digit Standard Industrial Classification (SIC) codes
or the six-digit North American Industrial Classification System
(NAICS) codes have been provided to assist you and others in
determining whether or not this document might apply to certain
entities. To determine whether you or your business is affected by this
document, you should carefully examine the applicability provisions in
40 CFR 720.22. If you have any questions regarding the applicability of
this document to a particular entity, consult the technical person
listed in the ``FOR FURTHER INFORMATION CONTACT'' section.
B. How Can I Get Additional Information, Including Copies of This
Document and Other Related Documents?
1. Electronically. You may obtain copies of this document from the
EPA Internet Home Page at http://www.epa.gov/. On the Home Page select
``Laws and Regulations'' and then look up the entry for this document
under the ``Federal Register - Environmental Documents.'' You can also
go directly to the ``Federal Register'' listings at http://www.epa.gov/
fedrgstr/. To access information about the TSCA New Chemicals Program,
go directly to the Home Page for the New Chemicals Program, within the
Office of Pollution Prevention and Toxics, at http://www.epa.gov/
opptintr/newchms/.
2. In person. The Agency has established an official record for
this document under docket control number OPPTS-53171A. The official
record consists of the documents specifically referenced in this
document, any public comments received during an applicable comment
period, and other information related to this document, including any
information claimed as Confidential Business Information (CBI). This
official record includes the documents that are physically located in
the docket, as well as the documents that are referenced in those
documents. The public version of the official record does not include
any information claimed as CBI. The public version of the official
record, which includes printed, paper versions of any electronic
comments submitted during an applicable comment period, is available
for inspection in the TSCA Nonconfidential Information Center, Rm. NE
B-607, Waterside Mall, 401 M St., SW., Washington, DC. The Center is
open from 12 noon to 4 p.m., Monday through Friday, excluding legal
holidays. The telephone number of the Center is 202-260-7099.
3. By phone. If you need additional information about this
document, you may also contact the person identified in the ``FOR
FURTHER INFORMATION CONTACT'' section.
II. Background
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 substance (as defined by section 3(2))
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 (also referred
to as a ``section 5 notice''). 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, unless the Agency has used its Significant New Use Rule (SNUR)
authority under TSCA section 5(a)(2) to designate a use of a chemical
substance as a ``significant new use.'' Section 5(a)(1)(B) of TSCA
would then require persons to submit a Significant New Use Notice
(SNUN) to EPA at least 90 days before they manufacture, import, or
process the substance for the use designated as significant. The
required SNUN provides EPA with the opportunity to evaluate the
intended use, and if necessary, to prohibit or limit that activity
before it occurs.
B. History
Since 1979, EPA has reviewed over 30,000 TSCA section 5 submissions
for new chemical substances. During the intervening years, EPA has
implemented various initiatives which have enabled the Agency to review
a greater number of new chemicals more
[[Page 60196]]
efficiently. In 1988, for example, EPA's Office of Toxic Substances
(now the Office of Pollution Prevention and Toxics) first used its
accumulated experience to group chemical substances with similar
physicochemical, structural, and toxicological properties into working
categories (USEPA, 1988, see Unit VI.8.). These categories, including
the subject one for PBT chemical substances, are developed by EPA based
on available data and experience reviewing PMNs on similar substances.
Such groupings enable both PMN submitters and EPA reviewers to benefit
from the accumulated data and decisional precedents and facilitates the
assessment of new chemical substances.
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 the insecticide DDT and
polychlorinated biphenyls (PCBs).
Establishment of a PBT category alerts potential PMN submitters to
possible assessment or regulatory issues associated with PBT new
chemicals review. It also provides 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 PBT new chemical substances; as such, it
is a major element in the Agency's overall strategy to further reduce
risks from PBT pollutants.
As described in the Federal Register notice of October 5, 1998 (63
FR 53417), development of the TSCA new PBT chemicals policy has
occurred in coordination with U.S. national, U.S./Canada binational,
and international efforts to identify and control the environmental
release of persistent organic pollutants (POPs). The proposed TSCA PBT
category has been provided to the Criteria Expert Group (CEG)
established at the first session of the Intergovernmental Negotiating
Committee (INC) for an International Legally Binding Instrument for
Implementing International Action on Certain Persistent Organic
Pollutants, in accordance with the mandate given by the Governing
Council of the United Nations Environment Programme (UNEP) in paragraph
9 of its decision 19/13 C (http://irptc.unep.ch/pops/
gcpops-e.html). The CEG is an open-ended technical working
group with a mandate to present to the INC proposals for science-based
criteria and a procedure for identifying additional POPs as candidates
for future international action. The CEG is to incorporate criteria
pertaining to persistence, bioaccumulation, toxicity and exposure in
different global regions and should take into account the potential for
regional and global transport, including dispersion mechanisms for the
atmosphere and the hydrosphere, migratory species, and the need to
reflect possible influences of marine transport and tropical climates.
At its first meeting, October 26-30, 1998 in Bangkok, the CEG
recommended that the INC consider developing a provision encouraging
countries and regions to include in their new chemicals schemes
elements relating to development and introduction of new chemical POPs.
The U.S. described its proposed TSCA new chemicals program policy for
the category of PBT new chemicals, and the full text of the October 5,
1998 Federal Register notice was distributed to all delegations as a
Conference Room Paper. The CEG's recommendation was accepted at the
second meeting of the INC (January 25-29, 1999 in Nairobi) and the INC
will consider it further in its deliberations.
This policy statement is important in our new chemical assessment
and TSCA regulatory programs, and represents the first formal statement
of national policy regarding new chemical ``persistent organic
pollutants.'' Under our domestic program, the policy statement provides
guidance criteria for persistence, bioaccumulation, and toxicity for
new chemicals and advises the industry about our regulatory approach
for chemicals meeting the criteria. Internationally, the Federal
Register notice of October 5, 1998 (63 FR 53417) alerted the parties
involved in negotiation of the POPs Convention to the need for
inclusion of a new chemicals provision in the Convention. The issuance
of the final policy statement will reaffirm US leadership on this issue
and serve as a model for other countries in taking steps to discourage
the introduction of POPs as new chemicals and pesticides.
III. Discussion of Final Policy Statement and Response to Comments
Today's policy statement adopts the criteria and testing strategy
of the Federal Register notice of October 5, 1998 (63 FR 53417), with
minor revisions. The Agency reviewed and considered all comments
received on the October 5, 1998 (63 FR 53417) notice. A complete copy
of all comments received is available in the public docket for this
document. A discussion of the policy statement, including a summary of
significant comments and the Agency's response follows:
A. Pigments
Comment 1-Pigments. Commenters suggested that EPA not identify
pigments as bioaccumulators and were concerned that testing could end
up being expensive for pigments, which are persistent by design.
Response. EPA assesses PMN chemical substances for PBT attributes
on a chemical-by-chemical basis, regardless of whether or not they fall
into a chemical use category such as pigments. Not all pigments are the
same and a precise definition of the term ``pigment'' is not available.
As a result, EPA does not have general ``pigments'' or ``dyes''
assessment categories; there are, however, more specifically described
categories of dyes or pigments that have been described by EPA (e.g.,
acid or amphoteric dyes, dichlorobenzidine-based pigments, and others;
see categories document at http://www.epa.gov/opptintr/newchms/
chemcat.htm). Moreover, the fact that a substance is ``persistent by
design'' by itself is not a sufficient basis for identifying a PBT new
chemical substance. Persistence is only one of three criteria used to
identify a chemical as PBT. When combined with a potential to
bioaccumulate, toxicity concern, and sufficient release to the
environment to result in potential risk or significant exposure,
pigments may be of concern, whether or not they are persistent by
design. If a PMN chemical is persistent by design, and becomes subject
to testing requirements by EPA, it would be counterproductive to test
initially for persistence, but rather to address the ``B'' and ``T''
criteria instead.
B. Ready Biodegradability Testing
Comment 2-Ready biodegradability testing. Commenters suggested that
EPA avoid the use of strict pass/fail criteria for ready
biodegradability of poorly water-soluble substances.
Response. Poor water solubility does not necessarily lead to
inability to pass a ready biodegradability test, as amply demonstrated
by the fact that many fats, oil, petroleum hydrocarbons, etc. easily
pass ready biodegradability tests. While strict OECD (Organization for
Economic Co-operation and Development) pass/fail criteria are given in
the OPPTS Ready Biodegradability test guidelines (see http://
www.oecd.org//ehs/test/degrad.htm and Testing Strategy for PBT Chemical
Substances, Unit IV.B. of this document), the Agency recognizes the
limitations in applying such criteria
[[Page 60197]]
rigidly given that many substances of concern as potential PBTs are
unlikely to pass ready biodegradability tests. A variety of critical
aspects beyond the pass/fail result will be considered when evaluating
potential new chemical PBTs or when testing decisions are made about
specific PMN substances. These more critical aspects include those
related to chemical structure (e.g., degree of branching) and
bioavailability (e.g., uptake of a substance by fish or
microorganisms), and their influence on both biodegradation and
bioaccumulation.
C. Bioconcentration Factor and Kow
Comment 3-Bioconcentration factor. Commenters requested
clarification on how bioconcentration factor (BCF) will be estimated
using calculations based on octanol-water partition coefficient.
Response. The octanol-water partition coefficient (Kow) is
correlated with the potential for a chemical to bioaccumulate in
organisms; the BCF can be predicted from log Kow, via computer programs
based on structure activity relationship (SAR). The Agency process for
predicting bioaccumulation factors (BAFs) and BCFs, along with
literature references, is described in some detail in the proposed rule
for lowering of reporting thresholds for certain PBT toxic chemicals
subject to reporting under section 313 (Toxic Release Inventory, or
TRI) of the Emergency Planning and Community Right-to-Know Act (EPCRA)
of 1986 (January 5, 1999 (64 FR 688) (FRL-6032-3), see page 704).
Comment 4-Log Kow and low solubility chemicals. Commenters
suggested that the October 5, 1998 (63 FR 53417) Federal Register
notice identified methods for calculating log Kow that are not
appropriate for organic pigments, which are insoluble in octanol. They
wanted to know how EPA handles low octanol or water soluble chemicals.
Response. EPA believes that the methods cited in the October 5,
1998 (63 FR 53417) Federal Register notice for experimental measurement
of the octanol/water partition coefficient (Kow), or SAR to predict
Kow, are appropriate, and the results of either can then be used to
predict the Fish BCF. Chemicals are unlikely to be accorded special
treatment in the new chemicals review process solely because of low
solubility in octanol or water alone. The test guidelines (OPPTS
830.7570 or 830.7560) cited in the October 5, 1998 (63 FR 53417)
Federal Register notice are viewed as the most appropriate for
measuring Kow, and alternatively, the shake-flask method (OPPTS
830.7550 test guideline) or the new ``slow-stir'' method currently
under development by the OECD, can be used. However, if the chemical
manufacturer still views these methods as inappropriate for a given
chemical, it would be advisable to proceed to more definitive testing
to address bioaccumulation potential (i.e., the Fish BCF study). This
approach can be applied to other testing endpoints as well; for
example, based on physicochemical properties of a particular PMN
chemical substance, a company might forgo a lower tier acute Daphnia
toxicity study in favor of the chronic study because it would yield the
best information for the screening level risk assessment.
Comment 5-Use of octanol solubility data alone. Commenters wanted
to know if octanol or fat solubility data can be used before
determining which chemical substances have the potential for
bioaccumulation.
Response. By itself, solubility in octanol (as a surrogate for fat)
is not a good predictor of potential bioaccumulation in fish. Kow is
correlated with the potential for a chemical to bioaccumulate in
organisms; the bioconcentration factor (BCF) can be predicted from log
Kow, via SAR. Kow is a coefficient which serves as a surrogate for the
partitioning of chemicals between water and fat, and cannot be
accurately estimated via separate determinations of solubility in pure
octanol and water (i.e., by calculating the ratio of the pure-solvent
solubilities) (Sijm et al., 1999, see Unit VI.1.). The Agency uses and
recommends the use of computer models to predict Kow where there are no
measured data.
D. Environmental Half-Life
Comment 6-Calculation of half-life. Commenters wanted to know how
half-life is calculated in the review of PBT new chemicals.
Response. Multimedia fate models like the Environmental Quality
Criteria (EQC) model (Mackay et al., 1996, see Unit VI.2.) require
compartmental half-lives for air, water, soil and sediment, which
cannot necessarily be interpreted as half-lives for any specific
process such as biodegradation. Data on air half-lives for input to
models would be either measured or derived from the Atmospheric
Oxidation Program (AOP or AOPWIN) or similar methodology. Studies by
Boethling et al. (1995, see Unit VI.3.) and Federle et al. (1997, see
Unit VI.4.) suggest that half-lives in bulk soil may be assumed for
screening purposes to be about the same as for surface water, and that
sediment half-lives may be assumed to be 3-4 times longer. EPA's
current suggested approach to finding water half-life is to use the
Ultimate Survey Model (USM) in the EPI BIOWIN program (Boethling et
al., 1994, see Unit VI.5.). Estimation of bulk compartment half-lives
from USM model data requires several assumptions, including that (1)
biodegradation is the only significant fate process in water, soil,
sediment; (2) water and soil half-lives are the same; and (3) sediment
is dominated by anaerobic conditions and therefore sediment half-life
is four times longer than water half-life.
E. Computer Models and the Use of Models vs. Actual Data
Comment 7-Use of models vs. actual data. Commenters support the use
of the Mackay/EQC model, but stressed the importance of having a
process for using actual data in place of the model.
Response. This is a reasonable suggestion. The EQC model is based
on the fugacity approach and subsequently applied to numerous
environmental processes. It uses an ``evaluative environment'' in which
environmental parameters such as bulk compartment dimensions and
volumes (e.g., total area, volume of soil and sediment, etc.) are
standardized, so that overall persistence for chemicals with different
properties and rates of transformation may be compared on an equal
basis. In general, measured values of toxicity, chemical properties,
compartmental transformation half-lives, etc., provided the data are of
acceptable quality, are preferred over those that are predicted or
estimated via a model or computer program.
Comment 8-Modeling of air releases. Commenters noted that the
October 5, 1998 (63 FR 53417) Federal Register notice considered only
biodegradation and aqueous hydrolysis and asked about fate of a
chemical upon release to air. They suggested that EPA estimate
atmospheric oxidation using AOPWIN.
Response. Although the testing strategy for this policy statement
focuses on biodegradability, all relevant transport and transformation
processes will be considered in evaluating the potential for a PMN
substance to behave as a PBT. Transformation processes not mentioned in
the Federal Register notice but which may be important for specific PMN
substances include atmospheric oxidation and photolysis, photolysis in
water, and redox transformations (of which there are various types) in
water, soil, and sediment. Although EPA believes that for most organic
chemicals, biodegradation in water, soil, and sediment will be the most
important
[[Page 60198]]
transformation process, each suspected PBT chemical substance will be
evaluated on its use and disposal patterns.
Clearly the atmosphere is an important environmental medium, and is
especially relevant where a substance is emitted directly to the
atmosphere or transported there via volatilization or aerosolization.
We know by deduction that it is only, or at least chiefly, through the
atmosphere that POPs like dioxins and Polychlorinated biphenyls (PCBs)
reach remote locations, and it will be an important factor in
determining the ultimate fate of many PMN substances as well. It is
through multimedia fate models such as EQC that atmospheric fate will
be considered in developing an overall prediction of environmental
persistence for suspected PBT substances. Where measured data are not
available, appropriate estimation methods such as that in the AOPWIN
program will be used to generate screening-level estimates of
atmospheric half-lives.
F. Use of ``Weight of Evidence'' and Professional Judgment
Comment 9-Laboratory vs. field behavior of chemicals. Commenters
indicated that EPA needs to incorporate any differences between lab and
field behavior of chemicals into its analysis of new chemical
substances, acknowledge the limitations of screening-level
biodegradation tests, and acknowledge the value of using professional
judgment when interpreting data from extended (> 60 day) degradation
studies.
Response. EPA recognizes that laboratory tests at best provide a
snapshot of expected environmental behavior, which ideally is studied
in the field. But since field testing is nearly always impractical for
PMN chemical substances, it is necessary to conduct laboratory tests
and to apply scientific judgment in extrapolating from lab to field.
EPA similarly acknowledges the limitations of ready biodegradability
and other screening tests as indicators of ultimate environmental
behavior. Finally, it is well known that even this policy statement's
higher tier (Testing Tiers 2 and 3) environmental fate guidelines,
despite being designed to provide test conditions closer to those
expected in the field, become less reliable when tests are run for
longer than the maximum duration specified in the guidelines. EPA will
give appropriate weight to these and other complexities in its
assessments.
Comment 10-``Check the box'' vs. ``weight of evidence.'' Commenters
noted that the TSCA PMN requirements for PBT chemicals look more like
``check-the-box'' than ``weight of evidence'' and wanted to know how
EPA will make professional judgment and use SAR and assessment methods
to identify PBT new chemicals.
Response. These tools (professional judgment, SAR, computer models,
assessment methods, etc.) would be applied to potential PBT chemical
substances in the same way they are applied to any other chemical
substance in the PMN review process. Using predictive tools (in the
absence of test data) and professional judgment, EPA leans towards a
``reasonable worst case'' when there is lack of chemical-specific data.
Industry always has the option of assisting and enhancing the Agency's
determinations by submitting scientifically valid test data. There are
a number of existing documents describing the PMN process and the
critical role played by SAR and professional judgment in that process,
including the Chemistry Assistance Manual for Premanufacture
Notification Submitters (USEPA, 1997, see Unit VI.6.) and parts of the
report on the joint U.S./European Union study that evaluated the
predictive power of the SAR (USEPA, 1994, see Unit VI.7.). EPA believes
that, where no or insufficient actual toxicity data exist upon which to
base a decision, toxicity estimates generated by SARs and other
predictive techniques may constitute sufficient evidence to be used in
human health and environmental hazard and environmental fate assessment
as components in certain risk determinations under TSCA (see also the
Federal Register of December 1, 1993 (58 FR 63507) for a similar
statement related to meeting section 313 listing criteria under EPCRA
of 1986).
Comment 11-Implement PBT policy within risk assessment framework.
Commenters suggested that EPA risk management decisions should not be
made solely on hazard information; these PBT criteria should be
implemented within a risk assessment framework. They indicated that
toxicity has been largely overlooked in the PBT scheme and no criteria
have been provided for toxicity. Commenters suggested that EPA needs to
take into account P and B and T before requiring further testing or
identifying a chemical as a ``true'' PBT, and asked whether persistence
and log Kow would be sufficient to determine that a PBT PMN chemical
substance may pose a significant risk. Commenters also suggest that EPA
should except non-toxic and low exposure/release substances from
consideration under this category and were concerned that the current
proposed criteria do not consider any health and safety benefits of a
PBT chemical substance.
Response. New chemicals identified as potential PBT chemicals are
assessed on a case-by-case basis. 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 (1) that 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), or (2) that 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 substance (``exposure-based'' finding). 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. EPA draws on
information and data submitted with the PMN form, other information
available to the Agency, and modeling (e.g., exposure, release, SAR,
etc.).
The Agency will consider P and B and T, individually and together,
and exposure in making risk-based judgments. Risk, specific to the PMN
substance as well as its risk relative to substitutes currently on the
market, is predicted as a function of the potential hazard of the
substance and the expected exposure. In other instances, as discussed
in the October 5, 1998 (63 FR 53417) Federal Register notice, during
PMN review EPA may determine 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. For such exposure-based determinations on suspected PBT new
chemicals, EPA will use a case-by-case approach for making findings by
applying considerations beyond P and B (i.e., toxicity or physical/
chemical properties), and consider P and B aspects as factors which
might argue for regulatory action under TSCA section 5(e) at lower
levels of production or exposure/release than are described in the
general guidelines for the new chemicals program's
[[Page 60199]]
exposure-based policy (USEPA, 1988, USEPA, 1989, see Unit VI.8. and
9.). Overall, companies are not being prevented from developing and
using new substances that are judged to be potential PBT chemicals, but
EPA may require certain controls (e.g., limiting the release of the PMN
chemical to the environment) or testing as a result of its assessments.
In order to be so identified as a PBT new chemical based on a risk-
based finding, all three criteria must be satisfied. The Agency has
adopted a 1 to 3 rating system for each of P, B, and T. If chemical has
a low Kow (i.e., ``B1,'' with BCF estimated as less than 1,000), the B1
rating does not support the new chemical's identification as a
potential ``PBT chemical.'' For example, some surfactants could be
P3B1T3; they are highly persistent in the environment and chronically
toxic to organisms, but with low bioaccumulation potential. However,
Agency action may still be taken under TSCA on chemicals not meeting
all of the PBT criteria, if they otherwise meet the risk or exposure-
based elements of TSCA section 5(e). Similarly, calcium would also not
be considered a PBT chemical, as it would be ranked P3B3T1; it is
persistent in the environment, it bioaccumulates, but it is not
considered toxic. Although the Agency does not promote the
environmental discharge of more persistent materials, the environmental
``desirability'' of a given chemical often depends on a balance of
various factors, including toxicity and ability of the chemical to
bioaccumulate. Like the previous surfactant example, the Agency may
nonetheless take action on a P3B3T1 chemical (not calcium per se), most
likely under its exposure-based authority.
The toxicity rating for a PBT chemical applies to repeated
exposures which result in human or environmental toxicity, including,
for example, systemic toxicity, mutagenic damage, reproductive
toxicity, or developmental toxicity. An example of this is chronic
toxicity towards aquatic organisms of organotins from contaminated
marine environments, which ultimately resulted in the regulation of use
of tributyl tin in marine anti-fouling paints. Repeated exposures
result from a PBT chemical after it has been released into the
environment, usually via contaminated water, sediments, or food. The
classic PBT problems (i.e., PCBs and Dichloro diphenyl trichloroethane
(DDT)) have been associated with food chain contamination.
G. Scientific Justification for PBT Technical Criteria
Comment 12-Support for lower threshold criteria for ``P'' and
``B.'' Commenters believed that there is little precedent, scientific
justification, evidence or data to support the lower regulatory
threshold of bioaccumulation factor of 1,000 and environmental
persistence of 2 months. They suggested that EPA needs a rationale for
these criteria beyond ``...are characterized by a tendency to
accumulate in organisms.''
Response. There is no ``bright line'' that clearly identifies a
bioaccumulation factor of 1,000 or a half-life of 2 months as the best
bioaccumulation or persistence criterion from a scientific perspective.
However, it is not accurate to state that there is no precedent or
basis for using these values. As outlined in EPA's recent proposal to
lower the reporting thresholds for PBT chemicals that are subject to
reporting under section 313 of EPCRA (64 FR 688; January 5, 1999),
similar values have been proposed by several authorities, including the
Ontario, Canada Ministry of Environment and Energy (MOEE) for its
Candidate Substances List for Bans or Phaseouts (MOEE, 1992, see Unit
VI.10.); the Canadian initiative for Accelerated Reduction/Elimination
of Toxics (ARET) (ARET, 1995 and ARET, 1994, see Unit VI.11. and 12.);
the International Joint Commission (IJC)'s Great Lakes Water Quality
Agreement (GLWQA) (IJC, 1993, see Unit VI.13.); and the United Nations
Economic Commission for Europe Convention on Long-Range Transboundary
Air Pollution (UNECE-LRTAP), which did adopt 2 months as the
persistence criterion of record for water (UNECE-LRTAP, 1998, see Unit
VI.14.).
In determining the thresholds for this policy statement, EPA
concluded that it would be appropriate to reflect the levels of concern
that the various PBT chemicals presented, based on the differing
degrees to which the chemicals persist and bioaccumulate. The Agency
ultimately chose to adopt a two-tier approach, and to establish two
separate thresholds to reflect the chemicals' varying potentials to
persist and bioaccumulate, as well as to reflect the Agency's belief
that the different levels of regulatory action under TSCA are warranted
for the two tiers. As discussed in detail in the preamble to the
mentioned EPCRA proposed rule, EPA found that generally the criteria
selected by various U.S. and international regulatory bodies for either
persistence or bioaccumulation clustered around two values. For
persistence in water, soil, and sediment, the criteria were grouped
around half-lives of 1 to 2 months and 6 months, and for persistence in
air, either 2 or 5 days. Bioaccumulation criteria were grouped around
BAF/BCF values of 1,000 and 5,000. The preamble to the EPCRA proposed
rule states ``Bearing in mind that one of Congress' articulated
purposes for EPCRA section 313 was to provide local communities with
relevant information on the release and other waste management
activities of chemicals in their community that may present a hazard,
EPA determined that the criteria that were most consistent with these
purposes were, for persistence, half-lives of 2 months for water,
sediment, and soil, and 2 days in air, and for bioaccumulation,
bioaccumulation/bioconcentration factor values of 1,000 or greater''
(64 FR 692; January 5, 1999). EPA is making a similar determination for
the PBT new chemicals policy under TSCA. The PMN process is one of
EPA's cornerstone Pollution Prevention programs and plays a critical
gatekeeper role in making sure that all new chemical substances do not
present unreasonable risks when they are commercialized. Given this,
and the uncertainty which often accompanies Agency review of a PMN
chemical substance due to lack of data, the TSCA new chemicals program
is and must be conservative by nature, which suggests that a half-life
shorter than 6 months and a BCF criterion lower than 5,000--values that
were selected solely or primarily to isolate substances already widely
acknowledged to be POPs are appropriate for regulatory scrutiny of new
chemicals under TSCA. Note that the CEG, at the October 26-30, 1998
Bangkok meeting described in Unit II.B. of this document, developed
indicative numerical values as bracketed criteria text which included
persistence of 2 vs. 6 months in water and log Kow of 4 vs. 5
(equivalent to a BCF of approximately 1,000 vs. 5,000, respectively).
A series of PMNs submitted to EPA in 1990 (Zeeman et al., 1999, see
Unit VI.15.) illustrates (1) why EPA believes that the persistence
criterion for bioaccumulating substances in soil, water, or sediment
should be set substantially lower than 6 months; and (2) that concern
for potential exposures to persistent and bioaccumulative toxics must
extend beyond the UNEP's 12 widely acknowledged POPs. The substances in
question were alkylated diphenyls, for which EPA expected discharge to
receiving streams and rivers. The submitter supplied data on use and
disposal, aquatic toxicity, and
[[Page 60200]]
biodegradability. The submitted environmental fate data and EPA
estimates of biodegradability based on structural analogs suggested
that half-lives in water would be well below 6 months, but not
necessarily lower than 2 months. As a result of concerns expressed by
EPA, use was limited to sites where resulting water concentrations
could be limited to 1 microgram per liter or less; concomitantly, the
submitter was also informed of EPA's belief that a potential for long-
term risk existed, but that EPA could not quantify this risk since
assessments typically evaluated releases over a period of only 1 year.
In 1998, results of monitoring revealed that the PMN substances had
been found in fish fillets and sediment samples from the receiving
stream. If, for these 1990 PMNs, EPA were to have had in place the 2
month persistence criterion described in today's policy statement,
further scrutiny under the new chemicals program would have been
warranted, and beyond simply informing the PMN submitter of the
potential for long-term risk, the Agency would likely have required
further testing to obtain an experimental value for environmental
persistence of the chemicals. This in turn would have given the Agency
a better picture of the behavior of the chemicals in the environment
and the environmental half-life relative to the 2 month value.
Comment 13-Deny commercialization to lower threshold PBT chemicals.
Some commenters supported exercising the ``Precautionary Principle'' by
not allowing commercialization under a TSCA 5(e) consent order or SNUR
pending testing of the PMN chemicals which meet the P=2 month and
BCF=1,000 criteria. They suggested that these chemicals should be
banned instead, pending the necessary testing.
Response. Whereas a half-life of 2 months and BCF of 1,000 can be
justified as lower-tier cutoffs in a deliberately conservative TSCA new
chemicals program that is designed to prevent commercialization of
potentially risky substances, it would not be appropriate to
automatically trigger a ``ban pending testing'' at these cutoffs given
the uncertainties about substance properties, release, and
environmental behavior that normally characterize PMN review. The
Agency believes that the available predictive tools and current
knowledge of POPs lend support for this two-phased approach to
screening of PBT chemicals and collection of information ``sufficient
to permit a reasoned evaluation of potential health and environmental
effects'' if EPA makes the requisite risk- or exposure-based findings
under TSCA section 5(e).
Comment 14-Relationship of P, B, and T criteria. Commenters
suggested that the October 5, 1998 (63 FR 53417) notice is inaccurate
when it states that 2 months is adequate for detecting many long-term
toxic effects as well as any tendency for a substance to bioaccumulate
in aquatic organisms. Commenters pointed out that the persistence
criterion is not related to detection of long-term toxicity.
Response. The statement in question was intended simply to note
that the 2 months half-life in water persistence criterion closely
tracks the duration of long-term environmental toxicity or
bioaccumulation tests. If a new chemical substance is predicted to or
measurably demonstrates chronic toxicity, potential to bioaccumulate,
and environmental persistence over that same time period (2 months), it
would meet the minimum TSCA PBT criteria. It is true that, in general,
half-life cutoffs for identifying POPs warranting international action
(e.g., in programs like UNECE-LRTAP and UNEP Global Negotiations on
POPs) have not been selected based on the duration of toxicity or
bioaccumulation tests. There are no cutoffs or ``fence lines'' for
environmental persistence criteria that emerge as immutable quantities
solely from scientific analysis; the choice of screening criteria is a
policy decision guided by the anticipated scope of a negotiation or
regulatory activity. In the case of the PMN program, 2 months
represents a reasonable screening level value for ``persistence'' which
is more than the 1-month period in a ready biodegradation study and
less than the 6 month value widely agreed to internationally (U.S.-
Canada binational agreement to control the discharge or release of POPs
in the Great Lakes Basin, UNECE-LRTAP, North American Free Trade
Agreement Commission for Environmental Cooperation (NAFTA-CEC), etc.)
as reflecting the persistence of known POPs chemicals (e.g., DDT,
hexachlorobenzene). As mentioned in the previous response, there is
international support, through the CEG, for persistence values of 2 or
6 months in water.
Comment 15-Relationship of P and B. Commenters suggested that the
October 5, 1998 (63 FR 53417) notice's statement, ``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,''
should be revised to reflect that persistence alone is not sufficient
to cause a substance to bioaccumulate.
Response. EPA did not intend that the sentence be read to mean that
persistence alone is sufficient to result in bioaccumulation. The point
that was intended to be conveyed was that a certain level of
persistence is a necessary condition for bioaccumulation to occur.
There are other conditions that affect bioaccumulation, such as
bioavailability and the metabolic transformation rate in the target
species. These and other factors will be evaluated by EPA in the
determination of the PBT concern level for PMN chemical substances.
H. Relationship of TSCA PBT Policy to Other Agency and International
PBT Initiatives
Comment 16-Finalize overall Agency multimedia strategy first.
Commenters suggested that the PBT classification criteria being
proposed for TSCA section 5(e) may have broader application, e.g.,
international or other Agency PBT initiatives, and may be used to
establish precedent in other programs. In addition to the TSCA October
5, 1998 (63 FR 53417) Federal Register notice, there have been three
other notices published in Federal Register dealing with (1) the
promotion of voluntary waste minimization efforts to reduce the
generation of those PBT chemicals which are found in hazardous waste
regulated under the Resource Conservation and Recovery Act (RCRA) (63
FR 60332; November 9, 1998 (FRL-6186-7)), (2) the Agency draft
Multimedia PBT Strategy (63 FR 63926; November 17, 1998 (FRL-6045-2)),
and (3) the lowering of reporting thresholds for certain PBT toxic
chemicals subject to reporting under section 313 (Toxic Release
Inventory, or TRI) of EPCRA of 1986 (64 FR 688; January 5, 1999). These
commenters stated that the TSCA notice is premature, occurring before
adoption of the overall Agency strategy, and is inconsistent with other
initiatives, domestic and international, which have lists of chemicals
and more selective criteria (i.e., specific to environmental media,
fate and transformation processes). Commenters recommended that EPA
finalize the Agency strategy first, before proceeding with the TSCA,
RCRA, and TRI actions, and that there should be coordination among them
all with uniform PBT criteria as part of the Agency strategy.
Response. The PBT Multimedia Strategy formalizes an Agency process
for integration of program activities involving these types of
substances. While the strategy intends to coordinate Agency PBT-related
activities under its
[[Page 60201]]
framework, the strategy does not establish rigid criteria with respect
to PBTs. Program offices must operate within the parameters of their
legislative mandates and established regulatory and policy frameworks.
For some programs such as the Toxics Release Inventory, the TSCA New
Chemicals Program and the RCRA National Waste Minimization Plan,
actions involving PBTs are a historical reality and their experience
has, in fact, largely shaped the strategy. Therefore, EPA does not
intend to halt all ongoing work involving PBTs until the strategy is
``finalized.'' With respect to the PMN process, it is important to
understand and acknowledge its fundamental purpose, which is to allow
EPA to evaluate the hazards, exposures, and risks of new chemicals, and
the opportunity to protect against unreasonable risks, if any. The
structure of that process and the tools used to implement it flow
logically from its statutory purpose and suggest that the category
approach outlined in this policy statement is the most appropriate
means of addressing potential concerns for substances possessing PBT
characteristics. It is EPA's intention that the strategy be a living
document. Therefore, the strategy will be updated based upon public
comment; it will not be ``finalized'' in the more traditional sense of
a rulemaking. EPA does agree that consistency is a laudable goal where
the criteria are meant to be used for similar purposes and is seriously
considering comments within the context of the strategy regarding
establishment of consistent criteria for priority PBTs.
Comment 17-Carefully communicate lower thresholds. Commenters
suggested that EPA should use only the environmental persistence of 6
months/BCF of 5,000 screening levels for consistency among EPA and
U.S./international programs and should carefully communicate proposed
lower criteria internationally.
Response. As discussed in the response to Comment 12, EPA believes
that a lower tier of 2 month/BCF of 1,000 is appropriate for risk
screening activities under TSCA. Communication is occurring in the
international forum. Unit II.B. of this document discusses the CEG for
POPs, established under UNEP mandate. At its first meeting, on October
30, 1998 in Bangkok, the CEG recommended that the INC consider
developing a provision encouraging countries and regions to include in
their new chemicals schemes elements relating to development and
introduction of new chemical POPs. The U.S. described its proposed TSCA
new chemicals program policy for the category of PBT new chemicals, and
the full text of the October 5, 1998 (63 FR 53417) Federal Register
notice was distributed to all delegations as a Conference Room Paper.
The CEG's recommendation was accepted at the second meeting of the INC
(January 25-29, 1999 in Nairobi) and the INC will consider it further
in its deliberations.
I. Testing Strategy
Comment 18-Toxicity testing. Commenters asked whether toxicity was
considered at each testing tier or only in tier 3. It was not clear to
them when toxicity testing would be requested, nor what results will be
considered acceptable by the Agency.
Response. Each of P and B and T are weighed in the Agency's
assessment. The testing strategy outlined in this policy statement is
intended to build the case, starting with testing to establish
persistence and bioaccumulation, and then determining toxicity and
confirming a chemical's status as a PBT chemical in tier 3. Once a
chemical becomes distributed in the environment at low concentrations,
the combination of persistence and bioconcentration in organisms can
result in residues high enough to approach a toxic dose. The first two
tiers focus on P and B because of the critical role these aspects play
in PBT determinations and because of their relatively lower cost to
determine P and B. Thus, chronic toxicity testing, which is expected to
be the most expensive testing, is reserved until tier 3 where it serves
to establish PBT status. Although the early tier P and B testing may
either obviate the need for toxicity testing or result in more directed
and cost-effective toxicity testing, the need for toxicity testing is
considered in each testing tier and will be obtained in lower tiers
where needed on a case-specific basis. As with all new chemicals
reviewed by the Agency under TSCA, the potential toxicity of the
chemical is determined from test data, if any, or by analogy to
structurally similar chemicals. If a company knows or suspects prior to
testing that their chemical is likely to be persistent and
bioaccumulative, consideration should be given to conducting chronic
toxicity testing in the first tier. For any suspected PBT chemicals for
which a risk finding has not been made, but which meet production,
release, and exposure thresholds under the Agency's exposure-based
policy (USEPA, 1988, USEPA, 1989, see Unit VI.8. and 9.), the standard
screening level battery of testing (or an appropriate subset thereof)
currently utilized for exposure-based cases in the new chemicals
program could be required in addition to PBT testing.
Comment 19-Equivalent tests. Commenters suggested that all tests
referenced in the testing strategy should also state ``or an equivalent
test.''
Response. EPA realizes that often there are a number of different
but acceptable means to providing testing information. However, EPA's
acceptance of a guideline not specified in this policy statement and/or
use of data generated under such guidelines depends on multiple factors
including the specifics of the test substance, purpose of the testing,
familiarity with specific procedures and equipment, validation of the
method, etc. Typical TSCA 5(e) consent orders require that testing
performed pursuant to the order must be conducted according to TSCA
Good Laboratory Practice Standards at 40 CFR part 792 and using
methodologies generally accepted at the time the study is initiated.
Before starting to conduct any such study, the PMN submitter must
obtain approval of test protocols from EPA by submitting written
protocols. Published test guidelines specified in the Test Strategy
section (see Unit IV. B. of this document) provide general guidance for
development of test protocols, but are not themselves acceptable
protocols.
J. Applicability of PBT Criteria to Metals
Comment 20-PBT criteria are not appropriate for metals. Commenters
suggested that the application of Persistence and Bioaccumulation
criteria appropriate for organic chemicals does not make sense for
metals and metal compounds. They also suggested that EPA needs criteria
to identify potential problems generated by organometals.
Response. The approach and the criteria are sufficiently flexible
to apply to organic chemicals, inorganic metals and organometallics. It
is important to distinguish between criteria for identifying potential
PBTs, on the one hand, and on the other: (1) the means of generating
information on the P, B, and T endpoints for comparison to the
criteria, and (2) the applicability of existing test guidelines for
generating such information experimentally.
EPA understands that metals are intrinsically not degradable in the
sense of ultimate degradation of organics (although they may undergo
biologically as well as chemically induced changes in, e.g., oxidation
state), and therefore are persistent by definition, but nevertheless
may not be bioaccumulative. It is widely accepted that elemental metals
are persistent by definition, since they may take different
[[Page 60202]]
forms that can be interconverted, but the elemental metal itself cannot
be destroyed. All elemental metals therefore meet the 6 month half-life
criterion. Given this, it is not correct that EPA's proposed
persistence criteria cannot be applied to metals. It may be more
accurate to state that the persistence criteria are not themselves very
helpful in screening or assessing metals and metal compounds with
respect to the potential for risk, whether from direct exposure or
through bioaccumulation. Relative to applicability of test guidelines,
the same level of judgment will be brought to bear such that, for
example, EPA would not require ready biodegradability testing for a
metal or metal salt. (EPA may, however, request such testing for
organometallics, which, depending on chemical structure, could still
show significant degradation in such tests.)
EPA understands that bioavailability is important in determining
the potential for risk, and notes that the same generalization applies
to any substance whether metallic or not. Metals and organometallic
compounds are no different from other organic chemicals with respect to
the applicability of the proposed criteria for identifying persistent,
bioaccumulative, and toxic substances, except that Kow determination
may not be relevant for metals (although the fish BCF study is
relevant). Similarly, it is not necessary to develop different criteria
or assessment strategies for pigments (see first comments/responses in
this policy statement) or any other specific classes of organics. What
is necessary is to consider what is known about the behavior of
substances like metals during the TSCA PMN review process, both in the
assessment of whether a given chemical substance meets the established
criteria and in subsequent testing decisions. For any untested PMN
chemical substance, if there are no close analogs with data and no
clear evidence that available estimation methods are unreliable for
this or closely related substances, then the estimation methods can be
assumed to apply and the resulting data compared to PBT criteria. Put
another way, a metal or organometallic (or, similarly, a pigment) that
is judged sufficiently persistent and meets the criteria for
bioaccumulation potential and toxicity is of concern for ``PBTness''
regardless of theoretical arguments or generalizations.
The key is how persistence and bioaccumulation potential are
determined in the PMN process, and by implication, how bioavailability
is determined. This policy statement leaves unspecified how EPA intends
to do this, but the Agency will consider all available and relevant
data, and will use its professional judgment in considering issues like
bioavailability of metals. Using lead as an example, many processes
commonly observed in the environment can result in the presence of
bioavailable (ionic) lead where it can be bioaccumulated by organisms.
These processes may occur in soil and aquatic environments with low pH
and low levels of organic matter. Under these conditions, the
solubility of lead is enhanced and, in the absence of sorbing surfaces
and colloids, lead ion can remain in solution for a sufficient period
to be taken up by biota. Lead sorption to soil organic matter has been
shown to be pH dependent. Decreasing pH can lead to increasing
concentrations of lead in soil and water. Microbial transformations in
soil, water, and sediment are also important in determining the overall
fate of metals and metal compounds, and therefore the potential for
formation of bioavailable forms. Metals are generally taken into cells
by nutrient metal transport systems, and these are not sufficiently
specific to completely exclude nonessential metals, some of which may
be toxic and/or bioaccumulative. In this situation, nutrient metals can
be displaced from their binding sites by undesirable, toxic metals,
which then gain access to the cell interior with concomitant exclusion
of the essential metal (Stumm and Morgan, 1996 see Unit VI.16.). Toxic
metal ions are then free to react with critical enzymes or otherwise
disrupt cellular functions if they reach certain levels. EPA concludes
that under many environmental conditions, metals and metal compounds
may be available to express toxicity and to bioaccumulate, and that
these effects are not necessarily limited to metals that are not
essential nutrients. It is appropriate, therefore, to be concerned
about the potential for risk from these effects. It is the policy of
the TSCA New Chemicals Program that if the metal in a metal compound
cannot become available as a result of biotic or abiotic processes then
the metal will not be available to express its toxicity, and by
extension, to bioaccumulate. If the intact metal compound is not toxic
and the metal is not available from the metal compound, then such a
chemical would not be a strong candidate for regulation under TSCA
section 5(e).
IV. Final TSCA New Chemicals Program Policy for PBT Chemical
Substances
A. Evaluation Criteria and Process for New PBT Chemical Substances
EPA is adopting 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(e) Action
---------------------------------------
5(e) Order Pending
Testing/ 5(e) Ban Pending
Significant New Testing2
Use Rule (SNUR)1
------------------------------------------------------------------------
Persistence (transformation half- > 2 months........ > 6 months
life).
Bioaccumulation (Fish BCF or 1,000. 5,000
BAF)3.
Toxicity........................ Develop toxicity Develop toxicity
data where data where
necessary4. necessary4
------------------------------------------------------------------------
1Exposure/release controls included in order; testing required.
2Deny commercialization; testing results may justify removing chemical
from ``high risk concern''.
3Chemicals must also meet criteria for MW (< 1000) and cross-sectional
diameter (< 20A , or < 20 x 10-8 cm).
4Based upon various factors, including concerns for persistence,
bioaccumulation, other physical/chemical factors, and toxicity based
on existing data.
Chemical substances suspected as persistent bioaccumulators under
the criteria listed in the table in Unit IV.A. of this document may
need to undergo testing on ``P'' and ``B'' endpoints which, if
confirmed, would be followed by appropriate toxicity testing to
identify ``PBT chemical substances.'' Control action under TSCA section
5(e) may be needed in varying degrees, based upon the level of risk
concern. 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 ``5(e)
Order Pending Testing/Significant New Use Rule (SNUR)'' could be
addressed via a negotiated consent agreement under
[[Page 60203]]
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. The ``ban pending
testing'' criteria are equivalent to those that have been used
internationally to identify POPs. For the chemical substances meeting
these criteria, 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 control
actions described in the table in Unit IV.A. of this document represent
just one body of possible decisions and should not be considered as
exclusive of other risk management options.
B. 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, that 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 that 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 or otherwise limit the manufacture, import, processing,
distribution in commerce, use, or disposal 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 EPA believes are needed to evaluate the
persistence, bioaccumulation, and toxicity of a PBT chemical substance
for which EPA has made the above 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.
As discussed in the response to Comment 19 in Unit III.I. of this
document, testing must be conducted according to TSCA Good Laboratory
Practice Standards at 40 CFR part 792 and using methodologies generally
accepted at the time the study is initiated. Before starting to conduct
any such study under the terms of a Consent Order under TSCA section
5(e), the PMN submitter must obtain approval of test protocols from EPA
by submitting written protocols. Published test guidelines specified in
Unit IV.B. of this document provide general guidance for development of
test protocols, but are not themselves acceptable protocols.
Tier 1. If, based upon available test data, 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. Hydrolysis
in water (OPPTS 835.2110 test guideline) should be determined if, based
upon SAR, susceptibility to hydrolysis is suspected. 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, CO2 Evolution, Modified MITI
(I), Closed Bottle, Modified OECD Screening, Manometric Respirometry.
2. Sealed-vessel CO2 production test (OPPTS 835.3120
test guideline).
If the measured log Kow is < 4.2 (equivalent to an estimated BCF of
1,000) 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 greater than or equal to 4.2, and
the chemical does not pass the ready biodegradability test, no further
testing will normally be deemed necessary in tier 1; the Agency would
likely 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). 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
sediment/water microcosm biodegradation test (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 > 1,000, tier 3 testing will normally 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
(OECD No. 422 test guideline) 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 (same as OPPTS test guideline
850.1400 (public draft)) and 40 CFR 797.1330 (same as OPPTS test
guideline 850.1300 (public draft)), respectively. Additional testing to
evaluate other biota (e.g., avian, sediment dwelling organisms) or
other effects (e.g.,
[[Page 60204]]
endocrine disrupting potential) will be considered where appropriate.
V. Intended Legal Affect of this Policy Statement
The policy discussed in this document provides general guidance on
the Agency's use of a category grouping for PBT new chemical substances
to facilitate the PMN assessment process for PMN submitters and EPA
reviewers. EPA uses groupings of new chemical substances with similar
structural and toxicological properties to allow PMN submitters and EPA
reviewers to benefit from accumulated data and decisional precedents,
as well as streamlined procedural requirements related to the review of
and follow-up for new chemical substances.
As guidance, the policy presented in this document is not binding
on either EPA or any outside parties, and this document is not
intended, nor can it be relied upon, to create any rights enforceable
by any party in litigation with the United States. Although this
guidance provides a starting point for assessing PBT new chemical
substances, EPA will depart from its policy where the facts or
circumstances warrant. In such cases, EPA will explain why a different
course was taken. Similarly, outside parties remain free to assert that
this policy is not appropriate for a specific PMN or that the
circumstances surrounding a specific PMN demonstrate that this policy
should not be applied. Although the Agency has provided an opportunity
for public comment on the guidance provided in this policy statement
and is likely to request additional feedback if changes are necessary
at some point in the future, the Agency may revise, clarify, or update
the text of this guidance without public notice.
VI. References
The OPPTS harmonized test guidelines referenced in this document
are available on EPA's World Wide Web site (http://www.epa.gov/
OPPTS-Harmonized/).
1. Sijm, D.T.H.M., Schuurmann, G., de Vries, P.J., Opperhuizen, A.
Aqueous Solubility, Octanol Solubility, and Octanol/Water Partition
Coefficient of Nine Hydrophobic Dyes. Environ. Toxicol. and Chem.
18:1109-1117.
2. 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.
3. Boethling RS, PH Howard, JA Beauman and ME Larosche. 1995.
Factors for intermedia extrapolation in biodegradability assessment.
Chemosphere 30: 741-752.
4. Federle TW, SD Gasior and BA Nuck. 1997. Extrapolating
mineralization rates from the ready CO2 screening test to activated
sludge, river water, and soil. Environ. Toxicol. Chem. 16: 127-134.
5. Boethling RS, Howard PH, Meylan W, Stiteler W, Beauman J, Tirado
N. 1994. Group contribution method for predicting probability and rate
of aerobic biodegradation. Environ. Sci. Technol. 28: 459-465.
6. USEPA. March, 1997. Chemistry Assistance Manual for
Premanufacture Notification Submitters. EPA 744-R-97-003. Also
available as Premanufacture Notification: Chemistry Assistance for
Submitters, by Steven C. DeVito and Carol A. Farris (ISBN: 0-471-19151-
5) through the publisher, John Wiley and Sons, at 1-800-225-5945 or the
TSCA Hot Line, at 202-554-1404.
7. USEPA. March, 1994. U.S. EPA/EC Joint Project on the Evaluation
of (Quantitative) Structure Activity Relationships. EPA 743-R-94-001.
8. USEPA. 1988. Letter from Charles L. Elkins to Geraldine V. Cox
(Chemical Manufacturers Association). Office of Toxic Substances, USEPA
(September 22, 1988).
9. USEPA. 1989. Letter from Charles L. Elkins to Geraldine V. Cox
(Chemical Manufacturers Association). Office of Toxic Substances, USEPA
(August 31, 1989).
10. Ministry of Environment and Energy for Ontario (MOEE). 1992.
Candidate substances list for bans or phase-outs. Report perpared by
the Hazardous Contaminants Branch and the Water Resources Branch, MOEE.
Ontario, Canada, ISBN 0-7729-9764-0.
11. Accelerated Reduction/Elimination of Toxics (ARET) Secretariat.
1995. Environment leaders 1. Voluntary commitments to action on toxics
through ARET. March 95.
12. Accelerated Reduction/Elimination of Toxics (ARET) Secretariat.
1994. The ARET substance selection process and guidelines. January 94.
13. International Joint Commission (IJC). 1993. A strategy for the
virtual elimination of persistent toxic substances. Vol. 1, report of
the Virtual Elimination Task Force to the IJC. Windsor, Ontario,
Canada, 72 pp.
14. United Nations Economic Commission for Europe, Convention on
Long-Range Transboundary Air Pollution (UNECE-LRTAP). 1998. Draft
composite negotiating text for a protocol on persistent organic
pollutants. UNECE, EB.AIR/1998/2, 31 March 1998.
15. Zeeman, M., D Rodier, and JV Nabholz. 1999. Chapter 2.
Ecological Risks of a New Industrial Chemical. Under TSCA. In
Ecological Risk Assessment in the Federal Government (Executive Office
of the President, National Science and Technology Council, Committee on
Environment and Natural Resources, Ed.). CENR/5-99/001, May, 1999, pp
2-1 to 2-30.
16. Stumm, W. and JJ Morgan. 1996. Aquatic Chemistry, 3rd ed. New
York: Wiley.
List of Subjects
Environmental protection, Chemical substances, Hazardous
substances, Reporting and recordkeeping requirements.
Dated: October 22, 1999.
Susan H. Wayland,
Deputy Assistant Administrator for Prevention, Pesticides and Toxic
Substances.
[FR Doc. 99-28888 Filed 11-3-99; 8:45 am]
BILLING CODE 6560-50-F