ASSESSMENT OF THE INPUT OF PHOSPHORUS AND NITROGEN COMPOUNDS INTO THE GULF OF FINLAND THROUGH TRIBUTARIES OF THE NEVA RIVER WITHIN THE BORDERS OF ST. PETERSBURG
The article is devoted to the actual problem of eutrophication of the eastern part of the Baltic Sea. The paper provides a general analysis of the intake of phosphorus and nitrogen compounds from the territory of the Russian Federation to the Gulf of Finland. Chemical analysis of water samples from the main tributaries and small watercourses of the Neva River delta within the borders of St. Petersburg was also carried out. Such watercourses as Okhta, Lubya, Okkervil, Slavyanka, Murzinka, Chernaya Rechka, Smolenka, Volkovka and Karpovka were studied. The concentrations of phosphates, ammonium and nitrate nitrogen were determined by spectrophotometry. Conclusions about the contribution of individual tributaries of the Neva River to the total inputs of biogenic elements into the Gulf of Finland were made. It is noted that the greatest contribution to the supply of biogenic elements is made by Okhta River and Slavyanka River.