Lake Onega water per year, of which 46% are industrial and household water, 25% is stormwater runoff and 16% is melioration-related drainage. This drainage contains of phosphorus and of nitrogen; respectively of these elements are removed through the River Svir whereas the rest accumulates in the lake. Ships and motor boats (about 8,000 units) bring oil pollution at the level of about per navigation year, as well as phenols (), lead () and oxides of sulfur, nitrogen, and carbon. The lake basin is a major source of granite, marble and black schist in Russia which have been exploited in the area since
Lake Onega and date back to between the 4th and 2nd millennia BC. There are about 1,200 petroglyphs scattered over the area including several capes, such as Besov Nos (see map above). The engravings are deep and depict animals, people, boats and geometrical shapes of circular and crescent shapes. Many other historical monuments are scattered around the lake. They include Svyat-Uspensky monastery on the cape of Murom, on the eastern shore of the lake. The monastery was founded in 1350, closed in 1918 and restored in 1991. Lake Onega Lake Onega (also known as Onego, ; or ; or ; or )