PAH loss during bioremediation of manufactured gas plant site soils

This research investigated loss of polynuclear aromatic hydrocarbons (PAH) while attempting to bioremediate soils from a manufactured gas plant (MGP) site. Laboratory microcosms using site soils were used to evaluate how environmental factors, such as temperature, pH and nutrients affected PAH loss. Results indicated that: (a) PAH in the MGP site soil resisted mineralization by microorganisms; (b) test soils were non-toxic before and after testing; (c) significant populations of bacteria were present in the microcosms during the degradation studies; (d) addition of free naphthalene and phenanthrene to the soils resulted in rapid loss of the added chemicals while the concentrations of indigenous chemicals were unchanged; (e) PAH were not soluble in a water extract of these soils; and (f) the PAH in these soils were unavailable for microbial degradation.