[Federal Register Volume 63, Number 214 (Thursday, November 5, 1998)]
[Notices]
[Pages 59780-59783]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-29665]
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ENVIRONMENTAL PROTECTION AGENCY
[OPP-00558; FRL-6042-3]
Pesticides; Science Policy Issues Related to the Food Quality
Protection Act
AGENCY: Environmental Protection Agency (EPA).
ACTION: Notice of availability.
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SUMMARY: To assure that EPA's science policies related to implementing
the Food Quality Protection Act (FQPA) are transparent and open to
public participation, EPA is soliciting comments on two draft science
policy papers--``Guidance for Submission of Probabilistic Exposure
Assessments to the Office of Pesticide Programs'' and ``Office of
Pesticide Program's Science Policy on the Use of Cholinesterase
Inhibition for Risk Assessments of Organophosphate and Carbamate
Pesticides.'' These policies have been peer reviewed by the Agency's
FIFRA Scientific Advisory Panel and are now ready for broader public
comment.
DATES: Written comments for each science policy paper, identified by
separate docket numbers provided in the ADDRESSES section, should be
submitted by January 4, 1999.
ADDRESSES: The docket number for ``Guidance for Submission of
Probabilistic Exposure Assessments to the Office of Pesticide
Programs'' is OPP-00559 and for ``Office of Pesticide Program's Science
Policy on the Use of Cholinesterase Inhibition for Risk Assessments of
Organophosphate and Carbamate Pesticides'' is OPP-00560. By mail,
submit written comments identified by the docket control number listed
for each to: Public Information and Records Integrity Branch,
Information Resources and Services Division (7502C), Office of
Pesticide Programs, Environmental Protection Agency, 401 M St., SW.,
Washington, DC 20460. In person, deliver comments to: Rm. 119, CM #2,
1921 Jefferson Davis Highway, Arlington, VA.
Comments and data may also be submitted electronically to: opp-
[email protected]. Follow the instructions under Unit V. of this document.
No Confidential Business Information (CBI) should be submitted through
e-mail.
Information submitted as a comment concerning this document may be
claimed 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. The public docket is
available for public inspection in Rm. 119 at the Virginia address
given above, from 8:30 a.m. to 4 p.m., Monday through Friday, excluding
legal holidays.
FOR FURTHER INFORMATION CONTACT: For ``Guidance for Submission of
Probabilistic Exposure Assessments to the Office of Pesticide
Programs'' contact by mail: Kathleen Martin, Environmental Protection
Agency (7509C), 401 M St., SW., Washington, DC 20460. Office location,
telephone number, and e-mail: 1921 Jefferson Davis Highway, Arlington,
VA, 703-308-2857, fax: 703-305-5147, e-mail: [email protected].
For ``Office of Pesticide Program's Science Policy on the Use of
Cholinesterase Inhibition for Risk Assessments of Organophosphate and
Carbamate Pesticides'' contact William Wooge, Environmental Protection
Agency (7509C), 401 M St., SW., Washington, DC 20460. Office location,
telephone number, e-mail: 1921 Jefferson Davis Highway, Arlington, VA,
703-308-8794, fax: 703-305-5147, e-mail: [email protected].
SUPPLEMENTARY INFORMATION:
I. Electronic Availability
A. Internet
Electronic copies of this document and the two science policy
papers 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/).
B. Fax-on-Demand
For Fax-on-Demand, use a faxphone to call 202-401-0527 and select
item 6021 for the draft document entitled ``Guidance for Submission of
Probabilistic Exposure Assessments to the Office of Pesticide
Programs'' and item 6022 for the draft document entitled ``Office of
Pesticide Program's Science Policy on the Use of Cholinesterase
Inhibition for Risk Assessments of Organophosphate and Carbamate
Pesticides.''
II. Background
On August 3, 1996, the FQPA was signed into law. Effective upon
signature, the FQPA significantly amended the Federal Insecticide,
Fungicide, and Rodenticide Act (FIFRA) and the Federal Food, Drug, and
Cosmetic Act (FFDCA). Among other changes, FQPA established a stringent
health-based standard (``a reasonable certainty of no harm'') for
pesticide residues in foods to assure protection from unacceptable
pesticide exposure; provided heightened health protections for infants
and children from pesticide risks; required expedited review of new,
safer pesticides; created incentives for the development and
maintenance of effective crop protection tools for farmers; required
reassessment of existing tolerances over a 10 year period; and required
periodic re-evaluation of pesticide registrations and tolerances to
ensure that scientific data supporting pesticide registrations will
remain up-to-date in the future.
Subsequently, the Agency established the Food Safety Advisory
Committee (FSAC) as a subcommittee of the National Advisory Council for
Environmental Policy and Technology to assist in soliciting input from
stakeholders and to provide input to EPA on some of the broad policy
choices facing the Agency and on strategic direction for the Office of
Pesticide Programs (OPP). The Agency has used the interim approaches
developed through discussions with FSAC to make regulatory decisions
that met FQPA's standard but that could be revisited if additional
information became available or as the science evolved. As EPA's
approach to implementing the scientific provisions of FQPA has evolved,
the Agency has sought independent review and public participation,
often through presentation of many of the science policy issues to the
FIFRA Scientific Advisory Panel (SAP), a group of independent, outside
experts who provide peer review and scientific advice to OPP.
[[Page 59781]]
In addition, as directed by Vice President Albert Gore, EPA has
been working with the U.S. Department of Agriculture (USDA) and another
subcommittee of NACEPT, the Tolerance Reassessment Advisory Committee
(TRAC), chaired by the EPA Deputy Administrator and the USDA Deputy
Secretary, to address FQPA issues and implementation. TRAC comprises
more than 50 representatives of affected user, producer, consumer,
public health, environmental, states, and other interested groups. The
TRAC has met five times as a full committee from May 27, 1998 through
September 16, 1998.
The Agency has been working with the TRAC to ensure that its
science policies, risk assessments of individual pesticides, and
process for decision making are transparent and open to public
participation. An important product of these consultations with TRAC is
the development of a framework for addressing key science policy
issues. The Agency decided that the FQPA implementation process would
benefit from initiating notice and comment on the major science policy
issues.
The TRAC identified nine science policy issue areas they believe
were key to implementation of FQPA and tolerance reassessment. The
framework calls for EPA to provide one or more documents for comment on
each of the nine issues by announcing their availability in the Federal
Register. In addition to comments received in response to these Federal
Register notices, EPA will consider comments received during the TRAC
meetings. Each of these issues is evolving and in a different stage of
refinement. Accordingly, as the issues are further refined by EPA in
consultation with USDA and others, they may also be presented to the
SAP.
In accordance with the framework described in a separate notice
published in the Federal Register of October 29, 1998 (63 FR 58038)
(FRL-6041-5), EPA is issuing a series of draft documents concerning
nine science policy issues identified by the TRAC that are related to
the implementation of FQPA. This notice announces the availability of
two draft documents. The first paper relates to science policy area #2
(Dietary exposure and Monte Carlo techniques) as described in the
framework notice published in the Federal Register of October 29, 1998
(63 FR 58038); this paper is one of three papers that will be issued
for comment. The second paper addresses science policy area #9
(Cholinesterase (ChE) Inhibition) as described in the framework notice
published in the Federal Register of October 29, 1998 (63 FR 58038); it
is the only paper for this area.
III. Summary of Draft Papers
A. Guidance for Submission of Probabilistic Exposure Assessments to the
Office of Pesticide Programs
EPA assesses pesticide dietary exposure from raw and processed
foods using two distinct pieces of information: The amount of pesticide
residue that is present in and on food (i.e., the residue level) and
the types and amounts of food that we eat (i.e., food consumption). The
residue information comes from the numerous crop field trials and other
sources where the amount of pesticide residues on a given commodity is
measured. Consumption information comes primarily from USDA surveys of
what people eat. In the past, EPA has used the Dietary Risk Evaluation
System (DRES) to combine the residue and food consumption information
with data on a pesticide's toxicity to calculate acute and chronic
dietary risk from food. This deterministic model calculates an average
value (sometimes referred to as a ``point'' estimate) for these
exposure and risk assessments.
The science of risk assessment is constantly evolving. As better
methods and techniques are developed, the Agency strives to incorporate
these into its risk assessment methodologies. Over the last few years,
a new technique has been applied to estimating acute pesticide dietary
exposure during a single day, which is a probabilistic evaluation
called Monte Carlo analysis. A probabilistic analysis uses the entire
range of data from the numerous crop field trial studies or other
sources to better estimate the distribution of exposure to the residues
for the population of concern. This technique allows for a more
realistic estimate of exposure, and depicts the variability in exposure
that results from differences in individual eating patterns as well as
differences in the levels of pesticide residues on food.
The Agency has been developing guidance on how to conduct
probabilistic exposure assessments for pesticides as well as guidance
to Agency reviewers on how to evaluate such assessments. In March 1998,
draft guidance was presented to the SAP. The SAP was very supportive of
the proposed guidance document and in general agreed with the proposed
approach. EPA has since revised the draft guidance, incorporating the
SAP's advice. Today, this revised draft guidance is being made
available for public comment. EPA is inviting public comment on several
issues listed in Unit IV.A.
The draft guidance is related to two of the other nine TRAC science
policy issues as follows:
1. Dietary exposure estimates (science policy issue area #4).
Dietary exposure estimates derived from probabilistic assessments are
one input in the overall assessment of dietary exposures.
2. Aggregate exposure (science policy issue area #7). Again,
exposure estimates derived from probabilistic assessments are part of
the aggregate exposures. Also, the use of probabilistic techniques is
being discussed among the scientific community as a method for
aggregating exposure from multiple sources and pathways.
The draft guidance is not intended to address the following two
other related issues:
1. The procedures (statistical and otherwise) used to address
situations where no residue is detected.
2. The rationale for the Agency's interim decision to regulate at
the 99.9th percentile of exposure when using probabilistic exposure
evaluation techniques.
Separate issue papers will be prepared according to the schedule in
the framework Federal Register notice to deal with these two topics.
A number of comments were provided by various industry and public
interest groups in response to the TRAC meetings, which began in May
1998. Commenters included the Natural Resources Defense Council (NRDC),
the National Food Processors Association (NFPA), Latham and Watkins,
and the Implementation Working Group (IWG). However, only IWG's
comments related to the draft guidance announced (in revised form) in
this Federal Register notice. The IWG, a coalition of farm, food,
pesticide manufacturing, and pest management organizations, provided a
``road map'' report entitled ``A Science-Based Workable Framework for
Implementing the Food Quality Protection Act.'' The IWG report stated
that the Agency should more fully utilize probabilistic techniques for
dietary, non-dietary and aggregate exposure assessments and that EPA
regulatory staff should become more familiar with the concepts of using
probabilistic analysis in decision making.
[[Page 59782]]
B. Office of Pesticide Program's Science Policy on the Use of
Cholinesterase Inhibition for Risk Assessments of Organophosphate and
Carbamate Pesticides
Most organophosphate (OP) and certain carbamate insecticides exert
their toxic effects on insects and mammals by the mechanism of ChE
inhibition. Communication between a large number of nerve cells in the
peripheral and central nervous system is by means of acetylcholine, a
neuro-transmitter. Acetylcholinesterase is the enzyme that breaks down
acetylcholine after it has communicated the nerve signal between two
nerve cells or nerve and muscle cells. Inhibition of this enzyme
prolongs the action of acetylcholine and results in the acute toxic
effects known for these chemicals such as nausea, dizziness, confusion
and, at high concentrations, more serious effects such as respiratory
paralysis and death. This can also result in chronic effects that have
been observed with many of these insecticides. Measures of
cholinesterase levels in the blood or nervous system after exposure to
OPs and certain carbamates have become the most common endpoint used in
risk assessments of these chemical classes. For at least the last 10
years, EPA has used plasma, red blood cells, and/or brain ChE
inhibition as the basis for determining critical effect levels and
setting reference doses.
Over the last several years, the Agency has engaged with outside
scientists and the regulatory community about which measures of ChE
inhibition may be used for setting reference doses in risk assessments.
Much of the discussion focused on two issues:
1. The role of blood measures, since blood cholinesterases are not
part of the nervous system and therefore are only an indirect measure
of neurotoxicity.
2. Whether plasma cholinesterases should be treated differently
from red blood cell cholinesterases.
In June 1997, the Agency made a presentation to the SAP including a
literature review, a series of case studies, a summary of activities
related to methodology of ChE measurement, and a briefing. This
briefing paper presented to the SAP, ``Office of Pesticide Programs
Science Policy on the Use of Cholinesterase Inhibition for Risk
Assessment of Organophosphate and Carbamate Pesticides'' (draft, April
30, 1997), provided EPA's analysis of the issues and options and its
proposed policy to use a weight of evidence approach that would
consider all of the data that might result in the use of ChE measures
in plasma, red blood cells, and/or the brain for defining critical
effects. In addition, EPA also asked the SAP about the feasibility of
using measures of peripheral nervous system tissue to replace blood
measures, which largely serve as indirect estimators of ChE inhibition
in the peripheral nervous system in animals. The report of the SAP
addresses these issues and is also included in the docket. The Agency's
briefing paper cited above has been updated and is being made available
for comment with this notice.
The IWG prepared a paper evaluating several science policy issues
relating to EPA's implementation of FQPA. Issue paper II of the IWG
report discussed the choice and use of endpoints in risk assessments of
ChE inhibitors and provided a number of comments about their use. The
IWG asserted several opinions: that ChE inhibition in blood itself is
not an adverse effect; that use of ChE inhibition in blood has the
effect of adding a safety factor; and that the additional safety factor
should be considered when applying other safety factors related to
infants and children.
During the public comment period for the SAP review, the Acute
Cholinesterase Risk Assessment Work Group, a group of pesticide
manufacturing organizations, proposed a complex alternative policy for
using measures of ChE inhibition in risk assessments. They proposed not
using plasma measures, reducing the uncertainty factor for red blood
cell measures, establishing a generic threshold of 20 percent
difference for blood or brain measures, and provided other comments.
The Natural Resources Defense Council, an environmental group, in a
brief oral presentation to the SAP, provided general support for the
Agency's proposed policy, but emphasized the need for broader pre-natal
and post-natal testing of pesticides to provide more data specific to
fetuses, infants, and children. This would, in their view, include both
cholinesterase data and data on a variety of neurological functions,
including in particular learning and memory.
Other regulatory bodies (i.e., agencies from California and Canada)
and public commenters from outside the United States (including
scientists from Great Britain and individual physicians who have worked
with the World Health Organization) described their own policies and
how those policies generally placed less reliance on plasma measures of
ChE inhibition as a risk assessment endpoint.
IV. Questions/Issues for Comment
A. Guidance for Submission of Probabilistic Exposure Assessments to the
Office of Pesticide Programs
1. Should outlier data points in residue or consumption data sets
be excluded from consideration? If so, then what should be the criteria
for excluding a data point from either food consumption or residue data
sets on the grounds that it is an outlier?
2. What criteria should be used to determine if a data set is
sufficiently ``representative'' of the population of interest to be
used in a probablistic assessment? Are there minimum size or Quality
Assurance/Quality Control (QA/QC) requirements that should be met?
3. Should the Agency allow exposure assessments to include data
reflecting the range of typical application parameters? Are the
conditions for accepting residue data based on typical parameters
appropriate, or should they be modified?
4. Do the currently available consumption data permit probabilistic
assessment of chronic dietary risk? If not, is there an appropriate
process for using the available consumption data to permit
probabilistic assessment of chronic dietary risk?
5. Is there a process or procedure which would allow the Agency to
utilize post-farm monitoring data on composite samples (e.g., from the
Food and Drug Administration (FDA), USDA, and State pesticide
monitoring data) to assess acute dietary exposure for unblended
commodities?
6. Is it appropriate to assess acute dietary risk on a population
basis, and to assess short- and intermediate-term occupational and
residential exposure on an exposed-individual basis? If it is more
appropriate to assess short- and intermediate-term occupational and
residential risk on a population basis, is there a process to do so?
7. What changes or additions to the document would improve its
readability and make it easier for general audiences to understand? For
example, would it be helpful to include a glossary of terms? Are there
key scientific concepts that need to be better explained for a lay
audience? Would the addition of a case study make any of the concepts
easier to understand?
B. Office of Pesticide Program's Science Policy on the Use of
Cholinesterase Inhibition for Risk Assessments of Organophosphate and
Carbamate Pesticides
1. How should EPA use measures of ChE inhibition in plasma, red
blood cells, and brain in determination of
[[Page 59783]]
critical effect levels and setting reference doses?
2. Should plasma and red blood cell measures of ChE inhibition be
treated differently from brain measures of ChE inhibition and/or from
one another?
3. How should measures of peripheral tissues be used in these
processes of risk assessment, both in a practical sense and a science
policy sense?
4. Can measures of ChE inhibition in peripheral tissues, such as
the heart and salivary glands, be used as a supplement or even an
alternative to blood measures?
5. Should comparative data on ChE inhibition in the young exposed
pre-natally, during infancy (nursing), and during childhood be
considered essential for defining the relative sensitivity of the young
and adults?
6. Are other measures, such as functional measures of clinical
signs, or learning and memory, similarly important?
Based on special additional recommendations of the SAP, EPA wishes
to highlight two other issues for public comment.
The first is the SAP's recommendation that plasma cholinesterase be
differentiated by use of selective inhibitors into acetylcholinesterase
and butyrylcholinesterase. At present, most animal studies received by
EPA do not differentiate between these enzymes. An important part of
the argument made for consideration of plasma activity was the fact
that for rat studies, nearly half of the plasma cholinesterase is
acetylcholinesterase, identical to the neuronal form. Such differential
analyses would provide additional data on this topic.
7. Should EPA require the differentiation of acetylcholinesterase
and butyrylcholinesterase in plasma, and how might this data be used?
The second is the SAP's recommendation that EPA ask for receptor
binding assays for long term studies. A common consequence of prolonged
ChE inhibition in the nervous system is the down regulation of
cholinergic receptors. This represents a longer term response to
exposure than the inhibition of enzyme activity. This effect might be
differentially affected by some chemicals, and its time course might
differ from enzyme activity. Such data would help to broaden the data
base on which to characterize the hazards of these chemicals.
8. Should EPA require receptor binding assays for long term
(subchronic and chronic) studies, and how should such data be
interpreted?
9. A number of parameters related to the neurotoxicological
potential of cholinesterase-inhibiting pesticides are measured and
considered when developing a hazard characterization for these
chemicals. Some of these parameters (e.g., clinical signs) represent
direct observations of this potential; others serve as surrogates
(e.g., inhibition of red cell cholinesterase) for potential effects not
currently measured or observed directly. OPP has proposed to use a
weight-of-the-evidence approach when characterizing the hazard of these
chemicals and developing health-based benchmarks such as reference
doses. A weight-of-the-evidence approach obligates the risk assessor to
consider all of the study results as a whole, rather than focusing on
any single result in isolation of the others. Is this approach a
reasonable means for evaluating the overall significance of the
potential neurotoxic effects associated with this type of pesticide?
10. What changes or additions to the document would improve its
readability and make it easier for general audiences to understand? For
example, would it be helpful to expand the glossary of terms? Are there
key scientific concepts that need to be better explained for a lay
audience? Would the addition of more examples make the concepts easier
to understand?
V. Public Record and Electronic Submissions
A record has been established for these policy guidances under
docket control numbers OPP-00559 and OPP-00560 (including comments and
data submitted electronically as described below). A public version of
this record, including printed, paper versions of electronic comments,
which does not include any information claimed as CBI, is available for
inspection from 8:30 a.m. to 4 p.m., Monday through Friday, excluding
legal holidays. The official record is located at the Virginia address
in ``ADDRESSES'' at the beginning of this document.
Electronic comments can be sent directly to EPA at:
[email protected]
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. All comments and data in electronic form must be identified by
the docket control numbers OPP-00559 and OPP-00560. Electronic comments
on this notice may be filed online at many Federal Depository
Libraries.
VI. Contents of Docket
Documents that are referenced in this notice document will be
inserted in the docket under the document control numbers OPP-00559 and
OPP-00560. In addition, documents referenced in in the framework
notice, which published in the Federal Register on October 29, 1998 (63
FR 58038) will also be inserted in the docket under docket control
number OPP-00557.
List of Subjects
Environmental protection, Administrative practice and procedure,
Agricultural commodities, Pesticides and pests.
Dated: October 30, 1998.
Lynn R. Goldman,
Assistant Administrator for Prevention, Pesticides and Toxic
Substances.
[FR Doc. 98-29665 Filed 11-4-98; 8:45 am]
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