MODELING THE FATE OF SURFACTANTS AND PESTICIDES IN A RICE FIELD

An ecosystem model is developed to be able to predict the concentratio n of either surfactants or pesticides in water, fish, rice and Crayfis h as a function of time after application (spraying). It is aim scope of the model to be able to give a quantitative comparison of the fate of the considered compounds and to use the comparison for a selection of an environmental strategy. The model seems to be able to offer such a comparison and also clearly shows that the concentration of surfact ants or pesticides is at the highest level in the Crayfish, due to its uptake of these compounds both from water and soil. It can be conclud ed from the results that the application of surfactants as an alternat ive to pesticides should be preferred from an environmental point of v iew, because not only will the surfactant bioaccumulate less than the two examined pesticides, but it is also less toxic to mammals. (C) 199 7 Elsevier Science B.V.