EVALUATION OF THE BIOREMEDIATION OF A CONTAMINATED SOIL WITH PHYTOTOXICITY TESTS

The fungal remediation of polycyclic aromatic hydrocarbons in contaminated soil from a hazardous waste site was evaluated in a pilot-scale treatability study. Higher plants were selected to evaluate the overall reduction in toxicity in the soil after fungal treatment because toxicity of a complex chemical mixture often is not easily measured by chemical analyses and disappearance of parent compounds may not indicate detoxification of the soil. Seed germination tests using soil samples and root elongation tests using soil eluates were conducted with three different species (lettuce, oat, and millet) before and after treatment. Phytotoxicity tests revealed significant detoxification of the soil after treatment with a good correlation with parent compound depletion. The seed germination test appeared to be more sensitive than the root elongation test, suggesting that the toxic compounds were not easily extracted from the soil to the aqueous solution. This study indicates that phytotoxicity tests have good potential to be used as an environmental tool to assess the efficacy of a remediation technology for site clean-up.