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The Daphnia magna Straus (1820) crustaceans are used in many countries to assess the quality of the environment. Researchers are guided more often by the mortality of individuals. However, the sublethal effects contribute to the development of biological early warning systems (BEWS). A visual method for recording the motor activity of D. magna was proposed. This method has advantages over automated analogs. It is simple, accessible to performers and does not require the use of special instruments. The method was tested under conditions of modeling the lethal and sublethal effects of heavy metal salts (Cu and Zn). The diagnosis of lethal doses is possible after 1 hour of exposure, whereas the death of crustaceans can occur in 3-4 days of the experiment. The effect of sublethal doses of heavy metals becomes statistically significant after 24 (p <0.05). The sensitivity of the method was confirmed in the studies of the aqueous extracts from the soils contaminated with various heavy metals (heavy metal processing area). The method showed good results in assessing the toxic effect of the waters anthropogenically contaminated with the mineral forms of nitrogen (NH 4 + and NO 3-) in the region of fertilizer production. The maximum inverse correlation between the motor activity and the concentration of ammonium ions in water (-0.83) was shown after 24 hours. Thus, the method of visual assessment of motor activity can be used in environmental monitoring.

Аn attempt is made in this work to establish correlations between the level of enzymatic activity of the soil and factors of an abiotic nature. It was found that the activity of invertase and urease in the soils of more southern territories is higher than that of northern ones. In soils with a pH value of the soil environment close to neutral reaction, the level of enzymatic activity is higher than in more acidic ones. The most sensitive to soil acidity among the studied urease enzymes. In relation to zinc, an inverse correlation was established between its content in the soil and the level of invertase activity. According to the degree of resistance to salinity, the enzymes are arranged in the following order: catalase> invertase> urease. An increase in the mineralization of the soil solution leads to an increase in the activity of urease. Of the studied enzymes, the most labile are representatives of the class of hydrolases (invertase and urease), less labile are oxidoreductases (catalase). Thus, when diagnosing the state of the soil by the level of enzymatic activity, it is necessary to take into account the main abiotic factors affecting the activity of enzymes: the average annual air temperature; pH and mineralization of the soil solution; the content of substances that inhibit microorganisms and block exozymes.

The areas near gas stations are places of local specific environmental pollution. The purpose of this work was to study the environmental consequences of gas station functioning on the surrounding soils (urbanozems). The content of oil products (OP), bulk and mobile forms of heavy metals, acute toxicity (Ceriodaphnia affinis Lillieborg, Раramecium caudatum Ehrenberg, Escherichia coli Migula), chronic toxicity (C. affinis), and the state of soil microphotrophs were determined. The content of OP was from 520±130 to 4820±100 mg/kg, which is significantly higher than the concentrations of OP in the soils of the transport zone of cities. The exceeding of the Russian standards for HM was found only for zinc (the maximum for the total form -1.7 MPC, for the mobile form -1.4 MPC). The urbanozems samples did not have acute toxicity; however, chronic toxicity in the bioassay for the mortality of C. affinis (up to 85%) and a decrease in the fertility of crustaceans (2-3 times compared to the control) were observed. In the structure of the community of soil microphototrophs, cyanobacteria dominated both in biomass and in abundance: (up to 748±10 thousand cells/1 g of soil) compared with green algae and diatoms (1.1-5.5 and 1.2-19.8 thousand cells/1 g of soil, respectively). As a result of the work, it was concluded that the quantitative algological analysis and biotest with the assessment of chronic toxicity in terms of mortality and fertility of C affinis for the diagnosis of local soil contamination in the areas of gas stations were of the highest informative value.

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