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ORD Pyrethroids Project
Abstract:
The U.S. Food Quality Protection Act of 1996 requires the Agency to consider the cumulative effects of pesticides and other substances that act by a common mechanism. Under the mandates of the Food Quality Protection Act, the EPA conducted a cumulative risk assessment for the organophosphate pesticides and is currently conducting an assessment on n-methyl carbamate pesticides. The available data for the pyrethroid insecticides is currently being reviewed to determine if this class of pesticide warrants a cumulative assessment.
To aid in this review and to strengthen the basis for a cumulative assessment, the EPA has promoted a multi-disciplinary effort.
EPA researchers are refining and applying their exposure and dose modeling tools to conduct a cumulative assessment. SHEDS (the Stochastic Human Exposure and Dose Simulation model) is EPA’s probabilistic human exposure model. ERDEM (Exposure Related Dose Estimating Model) is our dose modeling tool.
Measurement studies, data analysis, and SHEDS exposure modeling will be used to identify and quantify critical routes and pathways of exposure for the pyrethroid pesticides, and to assess population estimates of aggregate and cumulative pyrethroids exposure. This work will also identify the mixtures of pyrethroid pesticides that individuals are exposed to in real world situations.
To understand the relationship between exposure and internal dose, EPA investigators are working to develop human physiologically based pharmacokinetic (PBPK) models of pyrethroids. The PBPK models will be used to interpret the exposure data and compute dose metrics related to toxic outcome for multiple routes of exposures to pyrethroid mixtures.Objective:
The overall goal of this research is to develop state-of-the-art exposure and dose modeling tools to support EPA’s risk assessment of pyrethroids. Measurement data will be developed and analyzed to provide inputs to models, and to evaluate the models. Combined exposure and dose models will permit an evaluation of the simultaneous exposures of pyrethroid pesticides that lead to cumulative risk.
Relevance/Significance/Impact:
The Food Quality Protection Act of 1996 requires EPA to consider the cumulative effect to human health that can result from exposure to pesticides and other substances that have a common mechanism of toxicity. Through a coordinated multi-disciplinary effort which includes several EPA laboratories, this project will elaborate the general principles for considering cumulative exposure and for develop ing cumulative dosimetry models.
Principal Investigator: Dr. Rogelio Tornero-Velez