ATRAZINE BIOTRANSFORMATION IN WETLAND SEDIMENT UNDER DIFFERENT NUTRIENT CONDITIONS .1. ANAEROBIC

Anaerobic biotransformation of atrazine under three different nutrient conditions, i.e., D.I water, wetland water, and basal salt media (BSM ), was investigated with the sediment from a wetland receiving sugar m ill wastewater in Louisiana. None of the well-known metabolites and th eir hydroxy analogs, except hydroxyatrazine were detected in all sampl e reactors. About 50% of 10 mg/L of atrazine disappeared after 38 week s of incubation from liquid and sediment phases of the sample reactors with D.I. water and wetland water. However, more than 25% of the disa ppeared atrazine still existed as hydroxyatrazine in those sample reac tors. BSM substantially increased the removal rate of atrazine. Atrazi ne concentrations dropped to less than detectable level after 38 weeks of incubation in the sample reactors with BSM. However, the hydroxyat razine level in liquid and sediment phases of the BSM reactors was sti ll about 2.5 mg/L. BSM without (NH4)(2)SO4 decreased the atrazine tran sformation rate.