TA9 Ecological Risk Assessment and Landscape Ecological Modeling
D137-140
8:00 AM - 12:00 PM, Tuesday
() Enhancements to the Pesticide Risk Assessment Process.
Doelling Brown, P1, Hetrick, J1, Corbin, M1, Birchfield, N1, Abel, S1, Odenkirchen, E1, 1 U.S. Environmental Protection Agency, Arlington, VA, USA
ABSTRACT- Before a pesticide is registered for use in the United States, the U.S. Environmental Protection Agency (EPA) conducts an ecological risk assessment (ERA) to evaluate the potential for unreasonable risk to the environment EPAs Office of Pesticide Programs (OPP) evaluates proposed pesticide use through a tiered approach that includes Level I and II assessments. Level I is the traditional screening approach or deterministic method, where estimated environmental concentrations (EECs) are calculated using fate information and pesticide useage profile. If available, monitoring data is also used to determine EECs. Risk quotients (RQs), a ratio of EEC values to toxicity endpoints (e.g., LC50, EC50, NOAEC) are calculated. The RQs are then compared to pre-established Levels of Concern (LOCs) to determine the potential for acute or chronic risk to endangered and non-endangered species. Based on these results, EPA may conduct a more refined Level II assessment. The Agency is developing new Level II approaches and methodologies to better evaluate effects not completely addressed by the Level I assessment. Relatively new methodologies include probabilistic risk assessment techniques, such as how to extrapolate species sensitivity distributions from small data sets; and geo-spatial analysis of vulnerable locations, sometimes at a watershed specific or regional level. New approaches focus on a more holistic view of the ecosystem, using registrant provided data or open source literature to address both direct and indirect effects (e.g.,changes in ecosystem structure and function, food chain effects), and potential critical habitat impairment for endangered species. These efforts represent an on-going effort to use the best available science and make risk assessments transparent, clear, concise and consistent. Case studies of various pesticides will be presented. The views presented here are the views of the author and do not necessarily represent the views of the U.S. Environmental Protection Agency.
Key words: current use pesticides, eoclogical riak assessment, watershed level assessment, critical habitat effects