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
Onega, Russia of Onezhsky District, even though it is not a part of it. As an administrative division, it is, together with three rural localities, incorporated separately as the town of oblast significance of Onega—an administrative unit with the status equal to that of the districts. As a municipal division, the town of oblast significance of Onega is incorporated within Onezhsky Municipal District as Onezhskoye Urban Settlement. The economy of the town is based on timber industry. There is also production of construction materials. Onega is a minor port on a bay on the White Sea, which routinely freezes in winter. The