RELEASE OF POLYCYCLIC AROMATIC HYDROCARBONS FROM CONTAMINATED SOILS BY SURFACTANT AND REMEDIATION OF THIS EFFLUENT BY PENICILLIUM SPP.

摘要

Studies in which surfactants have been employed to increase the bioavailability of soil-bound polycyclic aromatic hydrocarbons (PAHs) have not yielded consistent results. Surfactant mobilization of high molecular weight (MW) PAHs from contaminated soils has not been extensively studied; therefore, the purpose of this research was to compare the extent of release of freshly added high MW ~(14)C-PAH with aged PAH from four different PAH-contaminated soils using a nonionic detergent, Tween 80, and to determine whether Tween 80-solubilized ~(14)C-PAH in soil washings could be degraded by indigenous microorganisms or by added Penicillium spp. Only very high concentrations of Tween 80 (>l,000 times the critical micelle concentration [CMC] for 3 of 4 soils) were able to mobilize bound ~(14)C-pyrene, -chrysene, and -benzo[α]pyrene. The concentration of surfactant required to release 50 of bound ~(14)C-PAH (the SC50 value) ranged from 5 to 30 g/L depending on soil type; a modest correlation was found (0.512) between the fraction of organic carbon in the soil and the SC50 value. At 10~4 × CMC, Tween 80 released an average of 75 of bound ~(14)C-PAH and 64 of the aged PAH, indicating that the ~(14)C-PAH release only slightly overestimated PAH mobilization from weathered soil. An exception was one soil that had been previously remediated in which <30 of the PAHs were released. The PAH structure had a negligible effect on the mobilization by surfactant because the solubilization curves for all three PAHs were very similar Tween 80-solubilized ~(14)C-pyrene readsorbed to soil when t