soil enzymes

Biodiagnosis of Soil with a Low Level of Anthropogenic Impact (with the typical Urban Settlement Stepnoe, Saratov Region, as an example)

Authors: Pleshakova Y. V., Ngun C. T., Reshetnikov M. V.

With the urban-type settlement Stepnoe as an example, biodiagnosis of the soil of a settlement with low technogenic impact was conducted. In the course of our work, 30 soil samples were plated onto solid nutrition media to evaluate the following: the total numbers of heterotrophic microorganisms - on meat peptone agar, the numbers of hydrocarbon-oxidizing and iron-oxidizing microorganisms - on their corresponding selective media, and the activity of several soil redox and hydrolytic enzymes (dehydro-genases, catalases, peroxidases, and invertases) were also studied.

INFLUENCE OF LEAD NITRATE AND ACETATE, WHEN INTRODUCED INTO SOD-PODZOLIC SOIL, ON ITS BIOINDICATIVE CHARACTERISTICS

Authors: Panova M. I., Pukalchik M. A., Uchanov P. V., Terekhova V. A.

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.

SOIL STATUS ASSESSMENT IN URBAN AREAS BY CHEMICAL AND ENVIRONMENTAL TOXICOLOGICAL METHODS

Authors: Olkova A. S., Berezin G. I., Ashikhmina T. Y.

The ecological status of soils in an urbosystem was assessed in terms of the total content of heavy metals, their mobile forms, petroleum products, integrated toxicity, and soil catalase activity. Parts of the functional transport areas of the city have turned out to be the most disadvantaged areas. A tendency of suppression of the ciliate motor activity and the growth indicators of watercress, reduction of the catalase activity in urban soils are observed.