|
Levels of radioactive cesium-137 in the ocean from nuclear weapons testing in the 1950s and '60s has gradually decreased as the radionuclide (which has a half-life of 30 years) has decayed. The Chernobyl a spike of cesium-137 in 1986. Measurements from a June 2011 cruise that came within 20 miles of the reactors at Fukushima found levels of cesium-137 approaching but not exceeding 10,000 petaBecquerels per cubic meter, which is the threshold considered safe for drinking water by the the U.S. Environmental Protection Agency. (Ken Buesseler, Woods Hole Oceanographic Institution)[back]
|
|
