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 Bay of the bay there are the town of Belomorsk and the outlet of the White Sea-Baltic Canal. From the east, the bay is limited by the Onega Peninsula. In the south-east, the town of Onega is located close to the shore of the bay. Administratively, the coast and the islands are shared between Kemsky and Belomorsky Districts of the Republic of Karelia, and Onezhsky, Primorsky, and Solovetsky Districts of Arkhangelsk Oblast. Most of the minor islands, including all of Sumsky Skerries, belong to Belomorsky District. The Onega Bay coast was populated by Russians (Novgorodians, of whom the pomors are the