Sometimes the lake is visited by very rare Armenian migrant lesser white-fronted goose ("Anser erythropus"). The rivers feeding Lake Sevan flow through densely populated settlements which produce agricultural, domestic, and industrial waste. It significantly changes the lake's ecosystem. According to a 2017 study the lake's water contains concentration of metals such as aluminium, nickel, arsenic, cobalt, and lead. According to Armenian environmental organization EcoLur, the lake is in a critical condition because of the presence of vanadium. Environmental Impact Monitoring Center, an agency of the Armenian Ministry of Nature Protection, reported in 2012 that the average annual concentration of vanadium (64 μg/l) in the samples taken from Lake Sevan exceeded the maximum permissible concentration (MPC) by 6.4 times, while selenium (26 μg/l) exceeded MPC 2.6 times, copper (21 μg/l) 2.1 times, magnesium (60 μg/l) 1.2 times. A 2016 study found that mining and metallurgical industrial activities—namely the Sotk gold mine on the southeastern shore of the lake—caused significant heavy metal, especially vanadium, pollution of the Sotk and Masrik rivers in the Lake Sevan catchment basin. According to the researchers it "may have posed health risks to aquatic life as well as to humans (at least in the case of river water used for drinking purposes)."