ABSTRACT
This chapter provides information available on transport and on transformation and degradation of pesticides in soil, and possibilities of prediction. Pesticides may be absorbed by soil organic matter as well as by inorganic soil fractions, and the relation between adsorption at sites depends on soil properties as well as chemical structure of the pesticide. Adsorption by inorganic and organic matter is not by just one mechanism of pesticide-soil interaction. Physical, physicochemical, and chemical processes are involved. Adsorption coefficients and constants related to soil organic carbon have been shown to be correlated with simpler physicochemical parameters. Mobility of pesticides in soil is related to adsorption, on the one hand, and the mass flux of dissolved fractions, on the other hand. Binding of pesticides to natural soil constituents is of paramount importance for their ecotoxicological evaluation. Volatilization of pesticides from soil is the transfer of the pesticides as a gas through the soil-air interface under environmental conditions.
