Soil Mutagenic Activity In Hazardous Waste Site Of Kalush City (western Ukraine)
R.A. Yakymchuk, V.F. Valyuk
Frequency and spectrum of cytogenetic disorders in the cells of root meristem sprouts of Triticum aestivum L., induced by soil contamination with hexachlorobenzene in the territory of toxic waste ground and Dombrovskyi potassium ore mine (Kalush city, Ivano-Frankivsk oblast), were studied. The concentration of hexachlorobenzene exceeded MPC (maximum permissible concentration) by 1233.3–18350 times. It has been established that chemical soil contamination causes the increase of the frequency of cytogenetic aberrations by 1.8-3.8 times. Its highest indicators were found under the most intensive soil contamination with hexachlorobenzene in the areas of toxic waste ground which were not recultivated. Frequency of cytogenetic disorders exceeded the control level by 3.4-3.8 times. The maintenance of high mutagenic activity of hexachlorobenzene remains in the soil of the recultivated area of the ground is confirmed by statistically reliable increase of the number of aberrant cells by 2.6-3 times. It has been shown that soil contamination of Dombrovskyi mine with the complex of natural-mineral compounds of mining-chemical raw materials causes the increase of mutagenic activity level of low concentrations of chemical gene-toxic factors of techno-genic origin, which is seen in the induction of higher level of cytogenic disorders compared with spontaneous indicators by 1.8-2.4 times. Spectrum of chromosome aberrations, which mostly included acentric fragments, expanded due to induced bridges, ring chromosomes and micronuclei. The share increase of the cells with dicentrics, caused by the effect of soil contamination with hexachlorobenzene in the territory of toxic waste ground, confirms the radiomimetic effect, resulted from the effect of chemical mutagen in high concentrations. Chemical pollutants of the soil of all the studied areas show the ability to cause mitosis disorder, connected with the damage of mitotic apparatus. A significant increase of disorder frequency of chromosome segregation can be the result of the interaction of mutagens not only with microtube proteins of division spindle but also with heterochromatin of near-center areas of chromosomes, which is typical for the mechanism of the emergence of cytogenetic aberrations under the effect of chemical supermutagens in high concentrations. The increase of the cell number with multiple aberrations under the effect of soil contamination with hexachlorobenzene in different concentrations proves high gene-toxicity of the chemical compound and the threat of severe genetic outcomes when it gets into the environment.