PW03 QSAR
Exhibit Hall
8:00 AM - Wednesday
(PW031) Development of a chemical structure-based predictive model for anaerobic biodegradation potential.
Aronson, D1, Tunkel, J1, Boethling, R2, Meylan, W1, Howard, P1, 1 Syracuse Research Corporation, Syracuse, NY, USA2 US Environmental Protection Agency, Washington, DC, USA
ABSTRACT- Fate assessment for chemical substances released to the environment focuses broadly on the four principal media--air, water, soil and sediment--and for many substances may also consider disposition in systems designed to treat wastes prior to release. At the screening level it is customary to assume aerobic conditions. However, aquatic and terrestrial environments and conventional wastewater treatment all have anaerobic compartments. Processes in those compartments are often critical in determining the overall fate of a substance. Anaerobic biodegradation is distinct and the microbial populations, their catabolic capabilities, and the environmental conditions under which they prevail are as complex and varied as their aerobic counterparts. Despite this, little work has been done to develop computer-based models for estimating anaerobic biodegradability from molecular structure. Our objectives were twofold; first, develop a comprehensive file of anaerobic biodegradation data; second, use the data to develop a model(s) for predicting anaerobic biodegradation potential from structure. To accomplish the first objective we started with the BIODEG and BIOLOG files of the Environmental Fate Database (EFDB), then supplemented this file with published and unpublished data from other sources. To accomplish the second objective we used a fragment contribution approach similar to the existing BioWin (EpiSuite) models, with modification of the fragment libraries consistent with current knowledge of anaerobic degradation pathways. As in the BioWin models, the new model classifies a substance as either fast or slow, in this case for the potential to be biodegraded in anaerobic sludge digestors. Results to be presented include limited external validation. Future work will focus on developing models for environmental compartments.
Key words: anaerobic biodegradation, environmental fate, sludge, estimation methods