Effect of Microbial Polymers on the Sorption and Transport of Phenanthrene in a Low-Carbon Sand

Abstract

Extracellular polymers of bacterial origin were analyzed for their effect on the sorption behavior of phenanthrene on a low-carbon aquifer sand. Batch experiments indicated that 85% of the polymers tested acted to decrease the distribution coefficient. Column experiments revealed a decrease in the retardation factor of phenanthrene by approximately 40% in the presence of an extracellular polymer produced by a Gram-negative motile rod isolated from a coal tar waste site. This polymer did not, however, influence the mineralization of phenanthrene and was not rapidly degraded by a mixed culture. The combination of the ability of the polymer to influence phenanthrene transport as well as its apparent persistence and lack of a negative effect on phenanthrene degradation suggest the extracellular polymers can act as agents that enhance PAH transport in natural systems. 50 refs., 8 figs., 2 tabs.