ABSTRACT
This chapter considers the presence and behavior of pesticides in soil leachates, the interactions of compounds with soil humus components, the biodegradability, and the transfer of pesticides and their metabolites to plants. Plant decay products and soil humus are the main sources of organic compounds dissolved in continental surface waters. The chapter discusses the chemical reactions of pesticide residues with both low molecular, water-soluble humic fractions and highly polymerized, insoluble fractions. Binding to highly polymerized unsoluble humic fractions greatly reduces the mobility of pesticides in soil bioavailability. The binding of pesticide residues to natural organic matter can be considered a key process that can be involved in the contamination of groundwater as much as in detoxification processes, depending on both the chemical nature of the pesticide and the characteristics of this organic matter.
