THE EFFICACY OF AMELIORANTS FOR REMEDIATION OF SOILS CONTAMINATED WITH HEAVY METALS, IN A LAB EXPERIMENT

The effectiveness of remediators in detoxification of soils contaminated with heavy metals was studied in a lab experiment. The objects of the study were the soils of the southern tundra, functioning under conditions of anthropogenic impact: Haplic Gleysols (Gelic) and Histic Fluvisols (Oxyaquic). The chemical ability of remediants to bind metals (Ni and Cu), transferring them to a sedentary state in comparison with the reference variants (without any addition of remediants), was evaluated. In experiments, remediants were used in three doses (D1, D2, D3): shungite; diatomite, glauconite and bentonite. To assess the immobilization of Ni and Cu in soils, acid-soluble (CR) forms (extraction of 1 n. HNO3), mobile forms (ammonium acetate buffer solution with pH 4.8), water-soluble forms of Ni and Cu (1:20 aqueous extract) were determined by inductively coupled plasma mass spectrometry. The effectiveness of soil detoxification during the application of remediants was evaluated by the phytotoxic effect in an express phytoassay with standardized tests (Brassica rapa CrGC and Avena sativa) represented by higher plants. A decrease in the proportion of mobile forms of Ni and Cu by 50% or more in Haplic Gleysols (Gelic) was revealed with the addition of any dose of ameliorants. The greatest effect of reducing mobility was exerted by shungite and diatomite at a dose of D1 - up to 15% Ni and Cu for Histic Fluvisols (Oxyaquic) soil. The use of the selected remediants in the indicated amounts did not reveal a phytotoxic effect on the tests in the experiment.