Models, field studies, laboratory experiments: An integrated approach to evaluate the environmental fate of atrazine (s-triazine herbicide)

Abstract A 3-step procedure was applied to the study of the environmental distribution and fate of atrazine. This comprised: (1) physical-mathematical models, following the fugacity approach; (2) field studies of the disappearance of atrazine from treated soil and a contaminated lake; (3) laboratory experiments to evaluate the main routes of disappearance of atrazine from fortified soils and waters. Models were used to evaluate the main trends in the environmental distribution of atrazine and to point out potential reservoirs and sinks. On the basis of these evaluations, field experiments were planned. Laboratory experiments were carried out to analyse the information from the field, by individual study of the main transport and transformation mechanisms. Through water runoff and leaching, atrazine tends to move from treated soils to water compartments. Volatilization from soils and water seems negligible. In water, the bioaccumulation potential of this chemical is poor (BCF c. 10, for fish muscle). The degradation in soil follows pseudo-I-order kinetics, t 1 2 around 50 days; similar kinetics have been found for atrazine degradation in natural lake waters, but with a slower rate ( t 1 2 = 168 days ).