Environmental assessment of small rivers in the central part of Khabarovsk in the period of snowmelt

The paper presents the results of microbiological and chemical-analytical studies of water and bottom sediment of small rivers, as well as snow in the central part of Khabarovsk during the spring flood in 2018. During an intense surface runoff in water of rivers, the content of ammonium nitrogen increases up to 5.4 times, nitrate - up to 6.8 times, nitrite - up to 3.3 times compared to the winter period. The increase in the content of labile organic matter and hydrocarbons caused a sharp increase in the number of heterotrophic bacteria in water up to 57 times, saprophytic bacteria up to 47 times, and hydrocarbon oxidizing bacteria - up to 23 times. The content of hydrocarbons in bottom sediment exceeds estimated concentrations up to 75 times, with maximum accumulation (22540 mg / kg) in bottom sediment of the Plyusninka River. Conditionally pathogenic micromycetes were detected in the snow cover.