The effects of metals (Сu, Pb, Ni, Cr, Cd) and fungicide alto-super on dehydrogenase activities of indigenous microflora of grey forest soil and laboratory culture Bacillus pumilus КМ-21 were studied. It was determined that the putting of the metals into soil caused the dose-effect inhibition of dehydrogenase activities of indigenous microflora of soil and dehydrogenase activities Bacillus pumilus КМ-21 estimated in eluate and contact tests. On the base of the established metal concentration causing the 50% inhibition on dehydrogenase activity, it was revealed that the contact test was more sensitive in comparison with eluate test. Cose relation between the alteration in activities of microbial culture (contact test) and indigenous microflora was shown. It allowed to recommend the contact test for estimation of the soil contamination with toxic compounds.

toxicants, soil, biotesting, dehydrogenase activity, grey forest soil.