BIOLOGICAL AND INTEGRATED CHEMICAL-BIOLOGICAL TREATMENT OF PCB CONGENERS IN SOIL SEDIMENT-CONTAINING SYSTEMS

A series of experiments was conducted on the integrated chemical-biolo gical treatment of C-14-labelled polychlorinated biphenyl congeners in soil/sediment-containing systems. The hydroxyl radicals, generated by Fenton's reagent (1% (v/v) H2O2, 1 mmol dm(-3) FeSO4), followed by in oculation with Pseudomonas sp., strain LB400, and Alcaligenes eutrophu s, strain H850, increased the overall extent of 2-chlorobiphenyl miner alisation in slurries of contaminated manufactured gas plant soil and sediment by 2.9 and 7.4 times, respectively, compared with biodegradat ion alone. In uncontaminated topsoil slurries the effect of chemical p retreatment was not observed. In the systems amended with 2,2',4,4'-te trachlorobiphenyl, the application of Fenton's reagent increased the o verall extent of mineralisation by 2.4 times, compared with the biolog ical treatment alone, but had no effect in the slurries of contaminate d soil and sediment. The increased level of radioactivity in the liqui d phase of experimental systems suggests that intermediates produced i n the process of chemical oxidation are less hydrophobic than parent p olychlorinated biphenyls and therefore more available for further biod egradation.