"Oleg Mitvol, deputy head of Rosprirodnadzor, has filed compensation claims against the Euro-Asian energy company and Norilsk Nickel for causing damage to water resources to the amount of $5.7 million and $178 million, respectively," the agency said in a statement.
After an inspection of the Russian nickel giant's West Siberian branch last summer, Rosprirodnadzor documented significant levels of untreated substances in a number of local rivers and other water basins, and gave the plant a warning over the pollution.
Norilsk Nickel said last fall that it would contest Rosprirodnadzor's claims and drafted a defense statement.
Natural Resources Minister Yury Trutnev pledged at the time that no claims would be made against the nickel giant.
As of last fall, the watchdog estimated environmental damage caused by Norilsk Nickel at about 2.7 billion rubles ($110.4 million).
In the lawsuit against the Euro-Asian energy company, a subsidiary of Evraz Group, one of Russia's largest steel and mining businesses, Rosprirodnadzor asked the company to repay over 141 million rubles ($5.7 million) for polluting two rivers in the Kemerovo Region, West Siberia.
The company was prescribed to stop the dumping of untreated waste into the rivers by December 30, 2007, but an inspection in early February 2008 revealed that Russian metal's giant was continuing to pollute rivers.