Recommendations

1. The Wallace Institute strongly encourages the adoption of probabilistic exposure assessment techniques consistent with the guidelines identified in Docket #OPP-00559. While important aspects of the assessment guidelines require further refinement, the Institute is in agreement with the vast majority of stakeholders who believe that probabilistic models represent a significant improvement upon conventional deterministic techniques.
   
   
2. The Wallace Institute recommends that the Office of Pesticide Programs (OPP) prohibit the exclusion of outlier data points solely on the basis of statistical tests. When representative of real world conditions, extreme values are an integral component for conducting assessments of acute human risk as they represent the potential worst case scenarios for exposure. The OPP should require all submissions to clearly identify significant mistakes in protocol to justify the exclusion of outlier data points.
   
   
3. The Wallace Institute is concerned that using probabilistic techniques to estimate occupational and residential exposure may underestimate the risk to highly vulnerable or exposed populations including farmworkers and their families. We are especially concerned that the high end exposures which can drive acute risk are not lost within a broad distribution of lesser values. The Institute urges the OPP to ensure that applying probabilistic techniques in occupational and residential settings fully meets the FQPA's protective requirements for highly vulnerable or exposed individuals.
   
   
4. The EPA's proposed guidance on probabilistic exposure assessment underscores the critical importance of pesticide residue data for the successful implementation of the FQPA. Improvements in conducting human health risk assessments will not yield benefits without data which accurately reflects real world exposure to pesticides. The Wallace Institute encourages the OPP to use its FIFRA data call in authority to work closely with the registrant community to utilize the most reliable residue monitoring practices for conducting probabilistic risk assessments. The cooperation of additional state, federal, and private stakeholders in the collection of necessary data, including food consumption patterns, will also be needed. The Wallace Institute strongly supports coupling methodological advances including probabilistic exposure assessments with the most accurate and pertinent data to provide the fullest possible benefit to pesticide applicators and the broader community of consumers alike.

General Comments

The Food Quality Protection Act (Public Law 104-170) significantly amends federal regulatory over the registration, use, and human health effects of restricted use pesticides. To ensure an adequate standard of protection, the law changes the tools and procedures used to calculate and assess human exposure to pesticides and their residues. Beyond these structural requirements, however, the FQPA codifies a new approach to risk assessment which reflects breakthroughs in the biological and toxicological understanding of pesticide exposure. These breakthroughs result from an analysis of the cumulative effects of exposure to multiple active ingredients from dietary, residential, and additional non-occupational sources. Advances in risk assessment make it possible to expand traditional one active ingredient, one route of exposure models to incorporate a more representative understanding of multiple compounds and diverse vectors. The scientific rationale behind the FQPA moves beyond a static, one dimensional approach to risk assessment to more closely simulate real world exposure. In the evolution of pesticide regulation, the FQPA represents the next generation of thinking. This innovative statute will require methodological innovations, as well as significant amounts of new data, for successful implementation.

The proposed guidelines for estimating human exposure outlines in Docket #OPP-00559 represent an important step forward in the science of risk assessment. The replacement of deterministic exposure models with probabilistic techniques is a methodological improvement which a broad array of stakeholders has welcomed. While supportive of the general provisions contained in the OPP's draft guidance, the Wallace Institute believes that several safeguards must be incorporated into the final policy. The OPP must carefully monitor the significance of outlier data points generated in the studies submitted in support of probabilistic exposure assessments. The outliers represent a significant source of acute risk and of particular concern to high risk populations such as children. High level exposures which drive acute risk must not be diluted by a broader distribution containing lower data points. Additionally, the OPP should adopt an extremely precautious approach as it applies probabilistic exposure techniques to occupational and residential assessments. High level exposures in occupational and residential environments are comparable to outlier data points in dietary assessment in that they represent worst case scenarios of acute risk. Probabilistic exposure assessment models can be beneficial for approximating risk at the level of an entire population, but this should not come at the expense of the most acutely affected individuals.

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