EFFICIENCY OF THE COMPREHENSIVE SORPTION TECHNOLOGY FOR CLEANING SOILS CONTAMINATED WITH HEAVY METALS
The goal of our study was in vitro evaluation of the ecological state of various soil types contaminated with heavy metals. In the process of remediation, we used different combinations of sorbents. We assessed the ecological condition of soils on the basis of chemical, eco-toxicological and microbiological analyses. We found the significant decrease of heavy metal concentrations in experimental soil samples from original 100 MAC to the maximum permissible concentrations of one or below one after we have used the following combinations of sorbents: activated carbon + clinoptilolite, and activated carbon + vermiculite. We discovered the correlation of soil sample toxicity (accounted for by the residual content of heavy metals) to the test objects (Chlorella vulgaris Beijer, Daphnia magna Straus). We identified patterns of changes in the qualitative and quantitative compositions of soil microorganisms in experimental samples in the course of remediation depending on a priority pollutant and main soil characteristics. Application of these sorbents resulted in increased microorganism numbers in the studied samples of contaminated soil already on the 7th day. In our study, we observed the restoration of the numbers of dominant microbial species and increase in the numbers of actinomycetes in various soil types on the 30th day of observations. The most effective was the sorbent combination of activated carbon and clinoptilolite in the 1 to 3 ratio.