FIELD-STUDY OF THE EFFECT OF SEWAGE-SLUDGE APPLICATION ON ATRAZINE BEHAVIOR IN SOIL

Atrazine dissipation was followed in a hydromorphic soil and a loamy soil amended with different kinds of sewage sludge. The ah azine was applied 5 months after the organic amendments. The hydromorphic soil was drained and water samples were collected for atrazine analyses. The atrazine dissipation was slower in the plot amended with sewage sludge, but after 12 months, non significant differences were found between the control plot and the amended plot. The highest concentrations of atrazine and metabolites were found in the water drained from the control plot, and the biodegradation degree, estimated from the deethylatrazine to atrazine ratio, was higher than in the amended plot. In the loamy soil, the dissipation kinetics were similar for all the sewage sludges; however, significant differences were found in the distribution of the atrazine residues with depth.