Surfactants at low concentrations stimulate biodegradation of sorbed hydrocarbons in samples of aquifer sands and soil slurries

Abstract

Abstract A study was conducted of the effect of two nonionic surfactants on the biodegradation of phenanthrene and biphenyl sorbed to aquifer material and soil. Alfonic 810–60 and Novel II 1412–56 at 10 and 100 μg/ml enhanced the extent of desorption of phenanthrene and biphenyl from aquifer solids, but concentrations of 1 μg/ml or lower were ineffective. The surfactants at 10 and 100 μg/g of aquifer solids enhanced the mineralization of phenanthrene sorbed to the solids, but the extent of mineralization was low. The addition of N and P to aquifer solids with the surfactants did not stimulate the biodegradation. Inoculation of aquifer solids with phenanthrene- or biphenyl-utilizing microorganisms stimulated the rate and extent of mineralization of the two compounds, and the rate was further increased by either surfactant. The rate and extent of phenanthrene and biphenyl mineralization in soil slurries was increased by either surfactant at 10 or 100 μg/g of soil. We suggest that surfactants at low concentrations may be useful for the bioremediation of sites contaminated with sorbed aromatic hydrocarbons.