Integral Bio Testing for the Risk Assessment of Crop Production in a Region of Russia with an Uncertain Ecological Well-being
Abstract
The integral biological testing of soil samples of four districts of the Tula region was performed. The Tula region was selected for the study because it was subjected to radioactive contamination in 1986 but at present, it is considered to be fairly safe for that matter. The districts were selected according to both the presence of industrial pollution and relative ecological safety. The use/non-use of land for crop production was also taken into account (eight sites in total, samples № 1-8). Three different bioassays were used: microorganisms Salmonella typhimurium, cell culture of mammalian Cricetulus griseus, and invertebrates Ceriodaphnia affinis. A relatively high direct mutagenic activity was detected at the sites of the Efremovsky and Shchekino districts (№ 1 and № 3 respectively), where the mutagenic index was 3.3 and 3.9 respectively. Substances contained in the № 2 and № 4 soil extract samples turned out to be pro-mutagens, i.e. induced mutations upon using metabolic activation. The soil samples, such as № 1 and № 3 also showed genotoxicity in Cricetulus griseus cells with the increase of the frequency of chromosomal and chromatid-type aberrations by several times, compared with control. In the experiments on Ceriodaphnia affinis, toxicity was detected in the № 1, № 3, № 5 and № 7 samples, in which the death rate of the crustaceans was 35-45 %, whereas, in the remaining samples, the decrease in the survival rate of the crustaceans did not exceed 15 %. Therefore, the integral bio testing enables detection not only in the presence of ecotoxicants but also it can indicate their origin - industrial or agricultural.
