FATE AND ENHANCEMENT OF ATRAZINE BIOTRANSFORMATION IN ANAEROBIC WETLAND SEDIMENT

We examined fate and anaerobic microbial transformation/degradation ch aracteristics of atrazine in wetland sediment receiving wastewater fro m local sugar mill. Well-known metabolites/intermediates of atrazine w ere not detected except hydroxyatrazine. Atrazine adsorbed on the sedi ment linearly with a distribution coefficient of 9.979 ml/g. Although we did not obtain a direct proof of atrazine mineralization, the value s of observed yield of total NH3-N were comparable to the theoretical values suggesting the biodegradation of atrazine to its end products o f NH3 and CO2. Only about 20% of atrazine was biotransformed to non-tr iazine species, possibly to the mineral end products, after 38 weeks o f incubation in the sample reactors without organic amendments, with m ethanol and sodium acetate. Acetic acid appeared to enhance the biotra nsformation of atrazine (both in aqueous and sediment phases) if one o nly measured the parent atrazine compound alone. However, a comprehens ive analysis of atrazine and its metabolites/intermediates showed that most of the disappeared atrazine existed as hydroxyatrazine. Glucose improved the wetland sediment's removal rate of the triazine species.