TOXICITY AND GENOTOXICITY ENHANCEMENT DURING POLYCYCLIC AROMATIC-HYDROCARBONS BIODEGRADATION

Several laboratory column percolators were operated in order to study the bioremediation potential of polycyclic aromatic hydrocarbons (PAH) -contaminated soils. The columns contained either soil artificially am ended with specific PAH mixtures or contaminated soil from a site in K arlsrhue, Germany. In all cases, biodegradative processes led to the e limination of the original contaminants. This, however, was accompanie d by a marked increase in genotoxic activity of the column effluents a s determined by the Mutatox(TM) assay. Genotoxicity was practically ab olished, however, when a surfactant was added to the percolating fluid s. While in some cases the changes in genotoxicity were paralleled by toxicity (Microtox(TM)) data, in others the trend was opposite. It is concluded that when degradation is incomplete, the potential exists fo r toxicity and genotoxicity enhancement, with the latter hazard not al ways predictable by short-term toxicity assays. Routine genotoxicity m onitoring is thus advocated for bioremediation projects; the Mutatox(T M) assay appears to be a convenient tool for this purpose. (C) 1994 by John Wiley & Sons, Inc.