Lake Karachay: - Russia
Lake Karachay: Most Polluted Spot on Earth - Russia
Lake Karachay is a small lake in the southern Ural mountains in western Russia. Starting in 1951 the Soviet Union used Karachay as a dumping site for radioactive waste from Mayak, the nearby nuclear waste storage and reprocessing facility, located near the town of Ozyorsk. According to a report by the Washington, D.C.-based Worldwatch Institute on nuclear waste, Karachay is the "most polluted spot" on Earth.
The lake accumulated some 4.44 exabecquerels (EBq) of radioactivity, including 3.6 EBq of Caesium-137 and 0.74 EBq of Strontium-90. For comparison, the Chernobyl disaster released from 5 to 12 EBq of radioactivity, however this radiation is not concentrated in one location.