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Process for Reviewing Tolerance Decisions Based on the Use of Anticipated or Actual Residue Data
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Introduction
EPA reviews pesticide tolerances that are based on anticipated or actual residue data. The information on this page may be useful to pesticide registrants, the environmental and public health community, growers, other pesticide regulators, or other stakeholders who want to understand better how EPA reviews and makes decisions regarding these tolerances. Basic information about pesticide tolerances.
EPA bases its tolerance risk assessments and decisions either on the assumption that residues will be present in food at the tolerance level, or on anticipated or actual residue data that more closely approximate residue levels that consumers may be exposed to in food.
By law, EPA is to require that data be provided to the Agency five years after it makes an initial tolerance decision based on actual or anticipated residue data. EPA must ensure that the data continue to support the safety standards in the law. After this first five year update, EPA may require new data, as appropriate to support the continuation of the tolerance. EPA collects updated information under the Food Quality Protection Act of 1996 (FQPA), which amended Section 408(b)(2)(E) of the Federal Food, Drug, and Cosmetic Act (FFDCA) 
EPA has a process for reviewing tolerance decisions that were based on the use of anticipated or actual residue data. The Agency uses this process to determine which data, if any, are needed to meet statutory requirements and to ensure that tolerances are safe.
FQPA required EPA to reassess all tolerances in effect as of August 3, 1996 (the date of enactment of the FQPA amendments) to ensure that they are supported by an up-to-date data base demonstrating safety. Thus, in most cases involving existing tolerances, the initial tolerance decision will be the tolerance reassessment decision required by FQPA. At the time a tolerance review is completed, EPA will determine when the next review will be scheduled. Generally, subsequent reviews will be done as part of Registration Review. However, EPA may require data and conduct reviews at any time, outside of the Registration Review cycle, if the Agency believes that the Agency’s review conclusions could reasonably change as a result of changed circumstances over time.
Below is a brief discussion of the primary types of anticipated or actual residue data used by EPA, followed by a description of the review process itself.
Types of Anticipated or Actual Residue Data
The types of data used for the initial tolerance decision affect whether changes in use practices by growers under an existing pesticide registration have the potential to raise residue levels in food above the anticipated or actual residue levels used in the initial assessment.
- Anticipated residue data are commonly drawn from crop field trial or food processing studies.
- Actual residue data come from monitoring studies and surveillance programs that sample foods and test for the presence of residues.
If the initial tolerance decision relied on anticipated residue levels from magnitude of residue studies, such as field trial, processing, and meat/milk studies, residue levels in food are generally unlikely to exceed the anticipated residue level in future years.
If the initial tolerance decision relied on actual residue data from monitoring studies and surveillance programs, however, changes in agricultural and food production practices could result in increases in residues that may require a change in EPA's initial tolerance decision.
EPA may rely on the following types of anticipated and actual residue data in making tolerance decisions.
Magnitude of Residue Data
Magnitude of Residue studies are generally conducted using the maximum amount of pesticide legally permitted to be applied according to the EPA-approved label and registration. In some circumstances, for scientific reasons, (for example, if the amount of residue expected to result from legal use is lower that the limit of detection of methods used to analyze food for the pesticide residue), studies are designed to exaggerate maximum label directed amounts. Generally, when these types of study data are used in making tolerance decisions, the next scheduled review will occur as part of the Registration Review Program.
- Field Trials
The most commonly used Magnitude of Residue data used in dietary risk assessments are data from crop field trial residue studies. The goal of field trial studies is to determine the maximum residue likely to result in or on food crops from legal use of the pesticide. Accordingly, crop field trial residue studies are conducted in several locations that are representative of the variety of growing conditions in areas where the crop is grown, and reflect maximum use rates, maximum number of applications, and minimum duration after application that the crop may be harvested (pre-harvest intervals (PHIs)), as defined by the pesticide registration and label.
Residue samples are obtained immediately upon harvest of the food commodity. Residues on food as consumed generally are lower than the values measured in crop field trial residue studies because of variations in use practices (either not using the pesticide at all or using it in a manner not likely to produce maximum residues), degradation of residues between time of harvest and consumption, and cooking and processing practices that break down residues.
Residue levels may change as use practices change. For example, growers may increase or decrease the amount of pesticide applied or the frequency of application – within the range allowed on the pesticide label – as pest pressures change. Such changes would not affect the residue levels measured in crop field trial residue studies, because such studies are designed to maximize residue levels, as described above. If the use patterns permitted by the pesticide registration and label are amended, however, (e.g., changes in pre-harvest intervals or application rates), crop field trials may become outdated. In general, EPA requires new field trials and conducts a revised risk assessment before granting registration amendments that might increase exposure to residues in food, to ensure that tolerances continue to meet food safety standards.
In instances where EPA has relied upon crop field trial residue studies in estimating anticipated residues, EPA believes that requiring registrants to submit new data bearing on anticipated residues would be of negligible scientific value in the absence of changes in the registration that might increase residue levels. Requiring the submission of new crop field trial residue studies would mean requiring registrants to duplicate existing valid and approved studies. Requiring the submission of monitoring data in such cases also would be of little value because monitoring data would only provide information on how much lower actual residue levels are, compared to the maximum values obtained through the standard crop field trial designed to produce maximum residues.
Food processing practices do not change significantly from year to year, and therefore EPA’s requirements for food processing studies change infrequently. Like field trial studies, processing studies are conducted so as to maximize the amount of residues permitted by the EPA-approved pesticide label, based on maximum use rates, minimum PHIs, etc. Unless processing practices and/or EPA-processing study guidelines have changed since the initial tolerance decision, EPA does not anticipate requiring additional processing data to verify its previous safety finding.
- Food Processing Studies
EPA requires animal feeding/meat and milk studies to support tolerance decisions when there may be residues in meat and milk resulting from pesticides used on animal feed crops, or when a pesticide may be used directly on the animal (e.g., to control ectoparasites). Like field trial and food processing studies, these studies are also designed to maximize the amount of residues resulting from maximum use of the pesticide according to its EPA-approved label. In the absence of changes in production practices, the studies used in previous tolerance decisions would continue to represent maximum residue levels. If new practices are adopted, EPA would need to evaluate whether new animal studies are warranted. If the pesticide registration is amended in such a way that pesticide residues would increase, a new study would be required as part of the registration amendment process.
- Meat & Milk Studies
Monitoring Data
Monitoring data reflect actual use patterns and may be expected to vary over time, depending on a number of factors, including the percent of the crop that is treated, application methods and rates, frequency of application, and timing of the last application prior to harvest. While food producers may not legally increase application rates or frequencies, or reduce pre-harvest intervals (PHIs), beyond what is specified on the EPA-approved label, they may use less of the pesticide, and the actual PHI may be longer than permitted by the label. Actual use of a product in a given season can be affected by many factors including pest pressure, product cost, availability of effective alternative pest control products and techniques, and development of pest resistance. As a result, (unlike data from controlled field trial, animal feeding, and processing studies), residues based on monitoring data may be expected to change over time, as practices change.
If EPA has relied upon monitoring data in its initial tolerance decision, some reanalysis of the initial tolerance decision and safety finding is necessary. If valid, current monitoring data are available, for example from the Pesticide Data Program or FDA surveillance programs, these data will be used by EPA to re-estimate residues. To the extent that data on the percent of a crop that is treated with a pesticide were used originally to inform the assignment of values to “non detects” within the monitoring data base, EPA will seek out new percent crop treated data to inform the new residue estimates. If valid, current data are not available, EPA will conduct an assessment to determine the likelihood that use patterns have changed in ways that would increase the frequency of detections or levels of residues present in food, compared to the data and information used to support the initial tolerance decision. If it is likely that use patterns have changed in a manner that would increase residues, the Agency will issue a data call-in (DCI) requiring new monitoring data, unless analysis of other available data and information demonstrates that safety standards are met.
Percent Crop Treated (PCT)
Percent crop treated (PCT) data are covered by a separate provision of the law. They are reviewed separately from anticipated or actual residue data and are subject to "periodic review" [see FFDCA Section 408(b)(2)(F)] . EPA does not routinely consider PCT in making a determination regarding the need for additional data in connection with tolerance reviews under the anticipated and actual residue provisions of FFDCA 408 (b)(2)(E), as described here. Overall, EPA intends to address PCT issues through the Registration Review program.
Review Process
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The anticipated/actual residue data review process is a tiered approach designed to focus EPA resources on tolerance decisions where new information could alter EPA’s initial tolerance decisions and safety findings. The Agency begins by reviewing all of the active ingredients scheduled for review within a given year, and assembling a list of all of the active ingredients for which initial tolerance decisions might have involved the use of anticipated or actual residue data for one or more commodities. Unless EPA is certain that none of the previous tolerance decisions were based on anticipated or actual residue data, the active ingredient will be included in the list for screening analysis. The Agency reviews the underlying assessments to verify which data were used to support the initial tolerance decisions for each active ingredient on the list. Below is a step-by-step discussion of the questions and considerations that EPA reviews in conducting its analyses. Attachment I (PDF) (1 pg, 19K, About PDF, ) is a chart summarizing the overall process.
1. What type(s) of data were used to support the initial tolerance decision?
- If Magnitude of Residue studies were used as the basis for the initial tolerance decision, it is unlikely that the anticipated residue levels were understated or that residues would change over time. Therefore, the review is complete and the next scheduled review will be during the Registration Review process.
- If monitoring data were used, residue levels may have increased if use patterns have changed since the initial tolerance decision. Therefore, further review is needed.
2. If monitoring data were used to support the initial tolerance decision, do valid current monitoring data exist?
- If yes, the analysis in Question 3 will focus on what the current monitoring data show.
- If no, the analysis in Question 3 will focus on changes in use practices. The level of analysis conducted to determine the significance of changes in use practices and their potential effect on the risk assessment will, in part, be based on the level of risk in the initial assessment. For example, if the initial assessment indicates a low risk, verifying the percent crop treated and total use may be adequate to determine that residues are unlikely to change in a manner that would affect the initial safety finding. However, if the estimated risk used for the initial tolerance decision is close to the EPA level of concern, a more comprehensive review of changes in use practices generally will be conducted.
3. Is there an increase in either the frequency of detections or the actual residue levels OR would changes in use patterns or the amount used be expected to increase residue levels?
- If current monitoring data show no increase in the frequency of detections or levels of residues, the review is complete. The next scheduled review will be during the Registration Review process.
- If current monitoring data indicate an increase in the frequency of detections or levels of residues, further review is needed.
- If no current monitoring data are available and use practices have not changed in a manner that would likely increase estimated residues, the review is complete. Depending on the level of risk found in the initial assessment, the next review may be scheduled as part of Registration Review, or at an earlier date.
- If no current monitoring data are available and use practices have changed in a manner that would increase actual residues, further review is needed.
4. If the anticipated or actual residue levels have increased since the initial decision, is a new risk assessment needed?
- If anticipated or actual residue levels have increased and EPA is confident that a new risk assessment will not affect its initial decision, the review is complete. This circumstance could occur if the increased anticipated residue level is on a food that is such a small contributor to aggregate exposure that the estimated risk will not change significantly, or if the risk estimate used in the initial tolerance decision was so low that even a large increase in residue levels would not raise risk concerns. In such circumstances, the next review will generally be scheduled as part of the Registration Review process.
- If the increase in anticipated or actual residue levels is large enough that it may raise risk concerns, new risk assessment will be conducted. This would occur if the initial tolerance decision was based on a risk assessment that did not have a very large margin of exposure (e.g., expected exposure constituted a relatively higher percentage of the RfD) or the commodity with the increase in anticipated residues is a major contributor to aggregate risk. The new assessment could be based on surveillance, monitoring, or other study data, depending on availability.
5. If a new risk assessment is needed, does the assessment indicate a potential risk of concern?
- If the risk from exposure to the pesticide in food has not changed, the review is complete. Generally, the next scheduled review will be during the Registration Review process.
- If the risk from exposure to the pesticide in food alone may be of concern, further review is needed.
- If the risk from exposure to the pesticide in food alone has increased significantly, but not enough for EPA to conclude that the safety standards are no longer met, a new aggregate risk assessment (including consideration of residues in food and drinking water as well as all other sources of non-occupational exposure to the pesticide) will be performed.
- If the aggregate assessment indicates that the tolerance continues to be protective, the review is complete. The next scheduled review will be determined on a case-by-case basis.
- If the aggregate assessment indicates that the tolerance may be of concern, further review is needed.
6. What type(s) of data were used in the new risk assessment?
- If Magnitude of Residue study data were used in the new assessment, and the assessment raises risk concerns, EPA would require monitoring data.
- If new monitoring data were used in the new assessment and the assessment raises risk concerns, EPA would take action designed to mitigate the risk, potentially modifying or revoking tolerances or amending the registration to lower aggregate exposure from food and/or non-food uses of the pesticide, as appropriate. Under these circumstances, EPA would implement mitigation to assure that the tolerance meets the current safety standards and make any necessary modifications to the tolerance within 180 days, as required by FFDCA 408(b)(2)(E).