New challenges: residential pesticide exposure assessment in the California Department of Pesticide Regulation, USA

Abstract

Residential exposure assessment is in an early stage of development within many of the regulatory agencies responsible for pesticides. Some of the impetus for residential assessment comes from the Food Quality Protection Act (FQPA), a federal law adopted in 1996 in the USA. The FQPA mandates that the aggregate and cumulative risks from all nonoccupational sources of exposure to similarly acting pesticides be assessed. The development of methods for residential exposure assessment is therefore proceeding in tandem with methods for aggregate risk assessment. The California Department of Pesticide Regulation (Cal DPR) regulates pesticides in the state of California much as the US EPA does at the national level. While Cal DPR is not explicitly bound by the federal law, it recognizes the importance of residential exposure and of cumulative risk, and tries to harmonize its methods with those of US EPA. Accordingly, Cal DPR is developing guidance for residential exposure assessment. Some factors to consider are the following: (1) although the end goal may be total exposure from all sources, in order to regulate the use of products it is necessary to have separate estimates of exposure from individual sources and routes; (2) probabilistic approaches will be used increasingly, and they must separate variability and uncertainty; (3) there is a critical need for data on residential use of pesticides, including the frequency of mishaps and improper handling; (4) data are needed on long-term activity patterns of individuals, including residential and occupational history; (5) regulatory agencies need a way to identify and screen potential exposure scenarios, in order to streamline the risk assessment process.