Photo- and Biodegradation of Atrazine in the Presence of Soil Constituents

The photo- and biodegradation of atrazine in the presence of several soil constituents, in particular earthworm casts collected from agricultural soils, were investigated. Earthworm casts were found to favour the photodegradation of atrazine but did not affect its biodegradation, as well as commercially available humic acids. The organic matter content of casts, even rather poor, increased the photodegradation rate. In contrast, the lack of effect of earthworm casts on the biodegradability may be due to the absence of minerals with swelling layers.