Fate and enhancement of atrazine biotransformation in anaerobic wetland sediment

We examined fate and anaerobic microbial transformation/degradation characteristics of atrazine in wetland sediment receiving wastewater from local sugar mill. Well-known metabolites/intermediates of atrazine were not detected except hydroxyatrazine. Atrazine adsorbed on the sediment linearly with a distribution coefficient of 9.979 ml/g. Although we did not obtain a direct proof of atrazine mineralization, the values of observed yield of total NH3-N were comparable to the theoretical values suggesting the biodegradation of atrazine to its end products of NH3 and CO2. Only about 20% of atrazine was biotransformed to non-triazine species, possibly to the mineral end products, after 38 weeks of incubation in the sample reactors without organic amendments, with methanol and sodium acetate. Acetic acid appeared to enhance the biotransformation of atrazine (both in aqueous and sediment phases) if one only measured the parent atrazine compound alone. However, a comprehensive 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.