Use of in vitro (Ames and Mutatox tests) and in vivo (Amphibian Micronucleus test) assays to assess the genotoxicity of leachates from a contaminated soil

Two in vitro bacterial assays (Ames test and Mutatox test) and one in vivo Micronucleus test on amphibians were used to assess the genotoxicity of aqueous leachates from a soil sample contaminated with polycyclic aromatic hydrocarbons (PAHs) and heavy metals. Positive results were obtained with the three tests: suggesting that this contaminated soil may be a threat to the aquatic environment. The test sensitivity was shown to be influenced by the experimental conditions. The response was higher with the nonfiltered leachate than with 0.45 mu m filtered one, which was the standard protocol (Norm X31-210). This standard procedure must be reconsidered in order to account for the pollutants adsorbed on solid particles which were biologically active. Incubation of bacteria in a liquid medium enhanced the sensitivity of the Ames test, by increasing the bioavailability of pollutants in comparison with the agar plate method. Biological tests appeared to be a useful complement to physico-chemical analysis, since they account for bioavailability and bioaccumulation of chemicals, and interactions between pollutants. (C) 1999 Elsevier Science Ltd. All rights reserved.