PARENT SESSION
PM16 - Probabilistic Ecological Risk Assessment
Monday, 18 November 2002
8:00 AM to 6:30 PM
Exhibit Hall

(P375) The Current Modeling Approach for Aquatic Exposure Assessment in the U.S. EPA Office of Pesticide Programs.

Lin, James^*,1, Young, Dirk¹, Kennedy, Ian¹, ¹ US EPA, Office of Pesticide Programs, Washington, DC., DC, U.S.A.

ABSTRACT- As a continued effort to reduce the uncertainties in aquatic exposure assessment, Environmental Fate and Effects Division (EFED) in the Office of Pesticide Programs (OPP) has begun a new initiative to move to a tiered approach to ecological risk assessments. The approach developed includes probabilistic tools and methods for use in the pesticide regulatory process, which would address the magnitude and probability of risk and provide an estimate of the associated uncertainty. The approach proceeds through four levels of analysis or refinement, from simple deterministic quotients through a general probabilistic analysis, to an issue-specific probabilistic assessment in the highest levels. This presentation provides an update on the recent Tier II modeling approach. In addition to standardize various modeling scenarios for PRZM (Pesticide Root Zone Model) to assessing aquatic exposure associated with pesticide applications to the different crops in different regions, the Tier II approach also consider the variable volume water body as the standard farm pond in EXAMS (Exposure Analysis Modeling System).

Key words: pesticide, aquatic exposure, modeling