Note: This information is provided for reference purposes only. Although the information provided here was accurate and current when first created, it is now outdated.
|SCIENCE POLICY AREA||CURRENT
IN RISK ASSESSMENT
SUGGESTIONS FOR IMPROVING TRANSPARENCY
|Applying the FQPA
10-Fold Safety Factor
|In assessing risk, the Office of Pesticide Programs
Retains the additional 10-fold safety factor unless reliable
information in the exposure and toxicity database indicate that it can be
Reduced or Removed.
EPA sought the advice of the FIFRA Scientific Advisory Panel (SAP) three times on various aspects of this provision. Stakeholders representing a spectrum of viewpoints have commented on OPP's approach. The SAP has been generally supportive of the new formal approach but identified the need for more clarity. EPA is responding to the SAP's suggestions and will present a status report to the SAP in July.
To maintain consistency across the Agency with respect to an additional safety factor in risk assessment, an Agency-wide Task Force is developing a unified set of criteria, which will provide a basis for identifying the data needed to make the 10-fold decision procedures for making the decision as transparent decision and procedures for making the decision as transparent as possible. EPA will publish the report of the intra-agency task force and issue fact sheets and other interpretive materials
We will prepare a draft guideline on applying the FQPA 10-fold safety factor that integrates further advice from the SAP and the intra-agency task force recommendations. The draft guideline will be published in Federal register for a 30-day comment period.
In the interim, we are using the guidance we presented at the March SAP meeting. In the event of any significant departures from the interim approach, we will provide public notice, consider public comments and consult with the SAP.
Late summer 1998
Revised draft policy to be published for comment in early fall 1998
|Exposure assessment --whether and how to use Monte Carlo analyses, including 99.9 percentile issue||Because the Federal Administrative Procedures Act requires that the Agency
make available to the public all data used in making a regulatory decision,
EPA cannot use Monte Carlo analyses that are based on proprietary databases.
EPA has accepted Monte Carlo analyses in those cases where we have received
permission to release the proprietary data used in the analysis.
EPA is developing the capacity to conduct acute dietary Monte Carlo analyses using non-proprietary dietary consumption data.
EPA presented draft guidance for conducting Monte Carlo analyses to the SAP in March. The guidance specifies acceptable inputs for Monte Carlo analyses. The SAP expressed divergent views on whether setting the criteria at the 99.9th percentile is an (adequately) conservative approach; a percentage of the population would still be exposed to levels that exceed the regulatory threshold. The margin of safety, variability in exposure and human thresholds for toxic effects, and possibility of separately modeling subpopulations were mentioned as factors to consider. EPA will publish draft guidance in the Federal Register for a #)-day comment period. After evaluation comments, EPA will publish final guidance.
EPA will investigate the feasibility of using Monte Carlo analyses to estimate exposures with other routes and durations.
Materials explaining the Monte Carlo concept is available on the EPA web site.
In the interim, we will use Monte Carlo analyses for acute dietary assessments where available data permit their use.
Draft guidance to be published by September 1998
|Exposure assessment -- interpreting "no residues detected"||Under EPA's current practice, if residues are present but not detected
for technical reasons, EPA uses a value of ½ the limit of detection
in the exposure assessment.
EPA has guidelines for establishing a "reasonable expectation of no finite residues" that are applicable under specific circumstances.
EPA is considering expanding the circumstances for finding "reasonable expectation of no finite resides." EPA will publish the proposed change in the Federal Register for a 30-day comment period. After evaluating comments, EPA will publish a new guideline.
In the interim, we are using the current "reasonable expectation of no finite residues" approach.
Draft to be published in October 1998
|Dietary exposure estimates||EPA has sufficient and reliable information to do preliminary dietary
EPA initially assumes that crops are treated at maximum use rates stated on the product label and then uses percent crop treated to refine dietary exposure estimates.
EPA is compiling information from users on actual use practices and other mitigating data to use in refining dietary exposure estimates. Issues include quality and representativeness of data.
|Drinking water exposures||The Agency currently uses scenarios and simulation models as screening
tools to estimate pesticide residues in ground and surface water. The use
scenarios are based on high end exposure potential. The models use extensive
data on each chemical's environmental behavior (e.g. persistence, mobility
) and on actual environmental conditions (e.g. soil types, rainfall). When
the pesticide passes the screen there is no need for further evaluation.
If the screen indicates potential drinking water exposures, EPA evaluates
data from the U.S. Geological Survey, states, and other sources to obtain
a more realistic estimate.
EPA is focusing on identifying populations that are likely to be exposed to pesticide residues in their drinking water. These people would represent the high end exposure population in the Agency's risk assessment.
The SAP reviewed EPA's approach in December 1997. The SAP approved of EPA's approach for screening groundwater for pesticide contamination but found that more work was needed on surface water models. In an April report of an October 1997 workshop, ILSI made a similar recommendation. EPA will present new methods for basin-scale estimation of pesticide concentrations in surface waters at the July Sap meeting. EPA is also evaluating a surface-water screening model developed by the American Crop Protection Association (ACPA). EPA will publish its revised drinking water exposure guidance (models) in the federal Register for a 30-day comment period.
In the interim, the Agency will use the most refined/available approach for drinking water assessments..
|Assessing "Residential" Exposure||EPA uses "scenarios" to model residential and other non-dietary,
non-occupational exposures (referred to as residential for ease of discussion)
because there are not survey data or other information that enable the Agency
to account for the nearly infinite variety of exposure settings and use patterns
that may occur. SAP has commented on these models. EPA will publish these
models in the Federal Register for a 60-day comment period.
The pesticide industry is generating data on residue levels on surfaces or in the air following pesticide application in various indoor and outdoor settings and EPA is developing guidance on assessing the transfer of these residues from the residential surface to the child's body.
EPA will use these data (and any other reliable data) to refine our exposure models. EPA will publish new draft guidance for residential exposure assessments to incorporate the new information.
In the interim, EPA will continue to use the best available combination of relevant data and model estimates to assess residential exposure.
|Aggregating exposures from all non-occupational sources||In February ILSI conducted a public workshop where 6 groups of experts
presented proposed approaches. Workshop participants evaluated and commented
on the approaches.
EPA will publish draft guidance on the conduct and evaluation of aggregate exposure assessments. There will be a 60-day comment period on the draft guidance.
In the interim, EPA will continue to aggregate its best estimates of all non-occupational exposure sources in determining whether the FQPA safety standard is met in any given situation.
|Report expected in July 1998
|How to conduct a cumulative risk assessment for organophosphate or other common mechanism pesticides||ILSI has concluded that there is no information to show that organophosphate
pesticides do not act via a common mechanism of toxicity, i.e., cholinesterase
inhibition. The SAP agrees with this conclusion.
In January, the Environmental Working Group (EWG) released a risk assessment of infants' and children's cumulative dietary exposures to organophosphate pesticides. EPA asked ILSI to evaluate EWG's assumptions and comment on EWG's methods. ILSI's report is expected soon.
EPA asked ILSI to develop a framework for the hazard characterization and the exposure assessment components of a cumulative risk assessment. ILSI will conduct a workshop in September and produce a draft document in early 1999.
EPA will publish draft guidance in the feral register for public comment.
In the interim, EPA will provide for public notice and comment for any cumulative risk assessment which it may develop for any group of pesticides.
Draft document in early 1999
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updated August 4, 1999