The influence of two lead salts on the enzymatic activity dynamics (urease, dehydrogenase, the total activity of hydrolases, acid phosphatase, and peroxidase) at lead ion concentrations of 10, 100, 300, 500 and 1,000 mg/kg in a model 21-day experiment was estimated. A significant inhibitory effect of lead nitrate on the total activity of hydrolases, dehydrogenase and peroxidase at doses of 500 and 1,000 mg (Pb2+)/kg was observed, while lead acetate was characterized by predominantly stimulating effect.