The main task of the Russian Geographic Society expedition on the research vessel 'Pavel Gordienko' Hydromet is to find radiation in air and water, Sea of Japan and the Kuril-Kamchatka region of the Pacific Ocean. The first stage of the expedition will last until May 20, the second – will begin in August or September 2011. The route runs from Vladivostok on the Sea of Japan between the Japanese islands of Hokkaido and Honshu by the Tsugaru Strait, and further along Kuril Islands to Kamchatka. 'The content of cesium-137 and cesium-134 in surface sea water, and at a depth of 50 meters is about 20 becquerels per cubic meter. At a depth of 100 meters level drops to 6 becquerels per cubic meter, at depths of 150 and 250 meters of man-made radionuclides were not found ", – said the chief flight Sevastyanov. In accordance with Russian norms of radiation safety for drinking water (sea water is not normalized) level cesium-137 content must be below 11 000 becquerels per cubic meter, cesium-134 – 7.2 thousand becquerels per cubic meter. Scientists also found in the air radionuclides iodine-131 and cesium-134 and 137 from the emissions from emergency plant. 'This is a small value, thousands of times less than the permissible activity in the air for the people ", – noted the official. First on the Kuroshio Meanwhile, Russian scientists were the first who measured the radiation levels at the northern boundary of the Kuroshio Current, which carries warm water from the tropics by Japan and then goes into the North Pacific for traveling to North America.