Lake Onega - Ecology

Ecology

Whereas the area of the lake used to be virgin, the pollution level is gradually increasing, especially in the northwestern and northern parts which contain industrial facilities of Petrozavodsk, Kondopoga and Medvezhyegorsk. About 80% of the population and more than 90% of industry of the basin are concentrated in these areas. The pollution from these three cities amount to about 190 million m³ of sewage and drainage water and 150 tonnes of emissions per year. Human activity results in about 315 million m³ of drain water per year, of which 46% are industrial and household water, 25% is stormwater runoff and 16% is melioration-related drainage. This drainage contains 810 tonnes of phosphorus and 17,000 tonnes of nitrogen; 280 and 11,800 tonnes of these elements are removed through the River Svir whereas the rest accumulates in the lake. Ships and motor boats (about 8000 units) bring oil pollution at the level of about 830 tonnes per navigation year, as well as phenols (0.5 tonnes), lead (0.1 tonnes) and oxides of sulfur, nitrogen, and carbon.