I understand your pain, knowing you live in the East end of the Gulf of Finland, very close to St. Petersburg. For the inland lakes and rivers being brown or latte'ish we can't blame the Russians, though, and not even agriculture. Admittedly the draining of swamps has still something to do with the hue, but even that is purely natural nonpoisonous stuff, used even for cosmetics. This summer I swam in quite a broad river in the south-west part of our country and the water was totally opaque! However swimming in it was considered totally safe, it was a public beach tested regularly for bacteria and other harmful stuff. The waterflow was simply carrying so much silt.