Modification of a bioassay with enchitreides for ecotoxicological assessment of contaminated soil
A.P. Baranov, M.I. Lunev, L.P. Voronina
Interpretation of bioassay results of both mono-contamination and complex multifactorial ones is carried out on the basis of comparison with the data of chemical analysis. Quite often, chemical analysis data correlate poorly with toxic bioassay indicators, which depend on both the bioavailability of pollutants, and the entire set of conditions of the contaminated area. In addition, in case of contamination with a pollutant of unknown properties or complex, multi-component contamination, it is difficult to select the necessary chemical analyses and obtain a complete picture of chemical contamination. However, the nature and source of the toxic effect may remain unexplained. Bioassay (test – Enchytraeus albidus) was carried out in the laboratory experiments with solutions and water extracts from the compost of sewage sludge. Lab experiments studied the possibility for the use of the antidote-1 (1-methylnicotinamide iodide) to determine the presence of metaphos and antidote-2 (dimercaprol sodium) to in turn determine the presence of Cd. Test- organisms (E. albidus) used for ecological studies to determine the toxicity in test-samples by bioassay undergo adaptation by preliminary treatment with specific antidotes. It was determined that use of adapted test-organisms to evaluate the toxicity of sample that has substance sensitive to the particular antidote leads to the decrease of toxicity. Thus the use of antidotes for bioassay may close the gap to our understanding of etiology and causes of toxicity of the sample under study. Further development of the study requires meticulous approach not only because of the change to bioassay but due to requirements for recultivation procedures for contaminated samples as well.