Integrated methodology to evaluate bioremediation potential of creosote-contaminated soils
Integrated methodology including chemical analyses as well as biological and ecotoxicological testing of soil was used to evaluate bioremediation potential of an aged, highly contaminated soil from a wood preservation plant. The soils contaminated with coal tar creosote originated from two sites (Site I: 8000 mg/kg and Site II: 133,800 mg/kg). A toxicity test-battery able to detect different effects using a variety of endpoints was developed and applied for the ecotoxicological assessment of creosote in soils: Azotobacter agile and Pseudomonas fluorescens dehydrogenase enzyme activity test, Vibrio fischeri bioluminescence test, Sinapis alba root and shoot elongation test and Folsomia candida mortality test. The biodegradation and its enhancement were investigated in small-scale bioreactors in short-term laboratory experiments. The joint evaluation of chemical, biological and ecotoxicological results made possible to compare different technologies, and investigate their applicability for remediation of soils contaminated with coal tar. The most sensitive direct contact tests that also correlated well with the creosote-reduction were Vibrio fischeri bioluminescence test, followed by Folsomia candida mortality test and Sinapis alba shoot elongation test.