MA3 Aquatic Ecotoxicology
254 Portland Ballroom
8:00 AM - 12:00 PM, Monday
() Spatio-temporal extrapolation in aquatic community-level effects of pesticides.
Brock, T. C. M.1, Roessink, I.1, 2, Van Wijngaarden, R. P. A.1, 1 ALTERRA, Wageningen UR, The Netherlands2 Wageningen University, The Netherlands
ABSTRACT- Case studies are presented of aquatic microcosm and mesocosm studies with pesticides that were performed in different periods of the year, and with different types of aquatic communities on the same (nearby) locality or in different geographical regions. The pesticides investigated comprise the insecticides chlorpyrifos and lambda-cyhalothrin, the fungicide fentin-acetate and the herbicide atrazine. Threshold concentrations for effects observed in different periods of the year and in different types of aquatic communities on the same locality are more or less similar. The extrapolation of NOECcommunity values from one system to another seems to be possible with lower uncertainty than hazard estimates of higher concentrations in which both direct and indirect effects and recovery processes are involved. When comparing pesticides for which at least 5 aquatic NOECcommunity values are available for a similar exposure regime (chlorpyrifos, atrazine) it appears that geographical extrapolation of threshold concentrations is possible with relatively low uncertainty. For these chemicals the geographical uncertainty factor (spread) for threshold concentrations was approximately 2-3.
Key words: spatio-temporal, ERA, extrapolation, pesticides