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(19-03) Relationship between pesticide Use and occurrence of aquatic species in the field. Vonk, Marijke*,1, Dick, de Zwart1, Dik, van de Meent1, 1 RIVM, Bilthoven, The Netherlands ABSTRACT- What is the effect of pesticide use on the occurrence of aquatic macrofauna species and waterplants under field conditions? We modeled the relationship between the observed occurrence of aquatic species in direct spray drift-exposed ditches all over the Netherlands and the predicted combined risk associated with the application of a wide variety of pesticides on a wide variety of crops. The pesticide risk is evaluated in combination with other environmental stress factors and site characteristics. The relationships between a range of environmental factors and ecological data from 1400 ecological surveys were calculated with the species oriented effect model, AQUAMOVE. This model consists of logistic response functions for about 650 macrofauna species and 150 species of waterplants derived by multiple GLM regression. The response functions describe the relationship between the probability of occurrence of a species and the combined toxic risk of pesticides, pH, oxygen availability, total nitrogen, total phosphorus, total ammonium, calcium, chloride, depth, width, length profile, soil type, substrate type, local land use, and their mutual interactions. Under field conditions, the absence or presence of species appeared significantly associated to the influence of pesticide use. Key words: Pesticides, Aquatic macrofauna, field effects |
