According to a study conducted by a marine radiochemist from the nonprofit Woods Hole Oceanographic Institution, Ken Buesseler, as a result of March 2011’s Fukushima disaster, there are raised levels of radioactivity off North American coasts.

More than four years after the meltdown of the nuclear power plant, researchers have tested hundreds of Pacific Ocean water samples and discovered trace amounts of isotopes of cesium, which is a quite reactive alkali metal. On December 14, Buesseler will present his results at the American Geophysical Union conference in San Francisco.

The study has suggested that cesium-134 was found within several miles off the Oregon, California and Washington coasts and also offshore from Canada’s Vancouver Island. It is an isotope directly associated with the Fukushima nuclear disaster, but having a 2-year half-life, it fades instantly.

Whereas, cesium-137 has been found in almost all the seawater samples, as it has a 30-year half-life and a part of them has been left over from nuclear weapons testing conducted in the 1950s to 1970s. As per the results, radiation was not just spread in a few locations, but it can be found along an area of over 1,000 miles (1,600 km) offshore.

They have collected a sample at 1,600 miles west of San Francisco. It has shown 50% rise in the cesium levels than all samples that had been gathered since an expedition Buesseler organized 3 months after the nuclear accident.

But, these levels don’t represent any danger to human or marine life, as they are 500 times lower as compared to the safety limits set by the US government. This has indicated that boaters, swimmers and other people part of recreational sea activities were not vulnerable. However, the findings have suggested that more research is in need to ensure that the radioactivity levels stay low.