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Languages : en
Pages : 28
Book Description
Many of the problem contaminants found in soils and groundwaters are non-ionic and relatively insoluble. Under appropriate conditions, many of these compounds are degradable by bacteria provided nutrients, electron acceptors and the compounds themselves are biologically available. However, non-ionic organic compounds (NOCs) bind tenaciously to soil particles potentially limiting their bioavailability. While the individual processes of sorption and biodegradation have received much attention in recent years, little is known about the interactions of these processes. The primary objective of our DOE-funded research project has been to elucidate the influences of sorption and desorption processes on the bioavailability of NOCs. Conflicting reports in the literature suggest that sorption may increase, decrease, or have no effect on bioavailability although the majority of published work has studied proteins, fatty acids, and other normal bacterial growth substrates as sorbates. Some of this variability arises because sorbed solutes interact with sorbents via different mechanisms including cation and anion exchange, adsorption, complexation with surface-associated metals and partitioning. Also, bacterial activities may be altered upon attachment of the cells to the sorbent surface. Clearly, resolution of this problem requires detailed knowledge of a system with multiple components. We are, therefore, approaching this problem on a fundamental level. 20 refs., 16 figs., 2 tabs.