Leaching of super(14)C-labelled atrazine in long, intact soil columns

A leaching study was undertaken with super(14)C-labelled atrazine in intact soil columns, 115 cm long and 19.1 cm diameter, to investigate the fate and transport of atrazine in a St. Samuel sandy loam soil. Results indicated a large variation in atrazine concentration in soil solution at various depths and in the leachate. The maximum levels in the leachate ranged from 0.0 to 11.2 mu g/L. Higher solution concentrations in the top 5 cm were correlated with higher moisture contents, suggesting desorption of atrazine with new water inputs. Deisopropylatrazine, one of the metabolites of atrazine, was detected near the soil surface but did not leach beyond the 15 cm depth. A large percentage of bound residues was found at various depths in three of four soil columns. A general trend towards increase in bound residues at lower atrazine concentrations was also observed.