BEHAVIOR OF ATRAZINE IN BRAZILIAN SOILS U NDER LABORATORY CONDITIONS

The persistence, mobility and adsorption of atrazine in two Brazilian soils (Gley Humic and Deep Red Latosol) were studied in laboratory, fo r 180 days after C-14-atrazine addition to the soil samples, incubated in the dark at 25 degrees C. Atrazine had a half-life of 56 days in H umic Gley soil and 54 days in the Deep Red Latosol. Hydroxyatrazine wa s the main metabolite, detected in higher percentage in the Humic Gley soil; the metabolites deetylatrazine and deisopropylatrazine were als o identified, but in lower concentration in both soils. Atrazine adsor ption in both soils was similar, K value of 2.6 and 2.1 in the Humic G ley and Deep Red Latosol respectively. After four runs in the soil thi n-layer plates atrazine had higher mobility in the Deep Red Latosol (R (f) = 0,74) to a R(f) = 0,66 in Humic Gley.