The US EPA has adopted Standard Operating Procedures (SOPs) for a variety of residential exposure scenarios involving contact with pesticides. The age of primary concern for many of these scenarios is children, yet exposure estimates for very few of those scenarios have been corroborated or validated with biomonitoring or some other form of passive dosimetry. In no small part this lack of validation is due to EPA’s regulation that prohibits their use of ethically and scientifically valid data unless those data would result in a more restrictive regulatory outcome. Insecticides incorporated into pet collars can be transferred to residents living with those pets. The standard method to estimate dermal exposure from such contact is to pet the treated animal in a prescribed, reproducible manner, and following quantitation of glove residues, and through a series of EPA’s calculations, to derive an absorbed dose of the insecticides. Those SOP-calculated exposures were compared to exposure estimated from biomonitoring residents with a treated dog in the house. The 2 methods’ resulting exposure estimates were compared for the insecticides TCVP and chlorpyrifos deployed in dog collars. For TCVP, the SOPs appear to overestimate the dose compared to estimates from children wearing T-shirts as dosimeters by a factor of 189 and from urinary biomonitoring data were 349-fold lower than the average SOP-derived dosage estimate. Similarly, for chlorpyrifos, the overestimating bias of the SOPs from children wearing T-shirts as dosimeters by a factor of 15 and from urinary biomonitoring data were 263-fold lower than the average SOP-derived dosage estimate. Thus, the data indicate that the SOPs overestimate pet collar exposure by 15 to 349-fold. Unfortunately, current regulation prohibits EPA from either recognizing these disparities or upgrading the SOPs to make them responsive to ethically and scientifically valid data.

Validating EPA’s Standard Operating Procedures for residential exposure to insecticide-impregnated pet collars

254th National Meeting (2017)

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