Abstract

PEIXOTO, Maria de Fátima da Silva Pinto; LAVORENTI, Arquimedes; REGITANO, Jussara Borges  and  TORNISIELO, Valdemar Luiz. Degradation and formation of ¹⁴C-atrazine bound residues in soils of the São Paulo state. Sci. agric. [online]. 2000, vol.57, n.1, pp. 147-151. ISSN 0103-9016.  http://dx.doi.org/10.1590/S0103-90162000000100024.

The objective of this study was to evaluate the degradation and formation of ¹⁴C-atrazine bound residues in two soils of the São Paulo State, Brazil. Hapludox and Umbraquults soils were incubaded for 63 days in 500 cm³ glass vessels with ¹⁴C-atrazine at 10.38mg a.i. g^-1 of soil. The ¹⁴CO₂ evolution was mensured weekly. Acetonitrile and water (4:1 v/v) was used as extractor solution of the herbicide residues and the organic matter fractionation was based on the solubility of the humic frations of acids and bases. The extracted residue were analyzed for radioactivity by using the Thin Layer Chromatography (TLC) method. The mineralization process (0.1% at 63 days after incubation) was insignificant for the atrazine detoxification in the Umbraquults soil. Hidroxyatrazine (HA) was the main metabolite of atrazine found in both soils and bound residue formation was an important process in that molecule dissipation, especially in the Umbraquults soil.

Keywords : atrazine; degradation; bound residues.