Scientists investigating the Fukushima Daiichi nuclear power works in Japan have found an unexpected source of radioactive material at the situation .

They found that sands and brackish groundwater up to 97 kilometers ( 60 miles ) by had retained some of the radioactive atomic number 55 from the cataclysm in 2011 , and this has been released into the sea .

The finding , lead by Woods Hole Oceanographic Institution ( WHOI ) , were publish in theProceedings of the National Academy of Sciences . Using thermionic valve 1   to 2   measure long ( 3 to 7   feet ) , they found that cesium level were 10 times high in the surrounding sand on eight beaches and groundwater than they were in the seawater in the harbour of the works itself .

Two isotopes of caesium were found . The first , cesium-137 , may have come from the plant or it could have come from atomic weapon system test in the 1950s and 1960s . They also find cesium-134 , however , which must have come from the plant life .

as luck would have it , these waters are not used for drunkenness and no one is exposed to them , so the generator said “ public health is not of basal concern ” in their paper . How , it ’s still an alarming example of how irradiation from the nuclear reactor has diffuse .

In the day and hebdomad after the accident , it ’s forecast that Cs was delight along the seashore and became stuck to George Sand grains . When it came into tangency with brine after from the sea , the cesium no longer get to the sand , and was carried   back into the ocean .

" It is as if the sands acted as a ' parazoan ' that was contaminated in 2011 and is only slowly being depleted , " said study co - author Ken Buesseler from WHOI in astatement .

The numbers are still low . The team estimate that this radiation , pair off with that from ongoing releases and runoff from the works , is M of metre humble than the release in the Clarence Shepard Day Jr. after the disaster .

But the source remark that , with about 200 nuclear reactors in the earth situated on a coastline , this variety of data is vital in work out how works can contaminate waters .

As for Fukushima , it ’s a tenacious and sluggish outgrowth to clean up the 2011 meltdown . Scientists have yet to retrieve all the melted fuel from the nuclear reactor , and even once that ’s done , the plant life is not expected to be decommissioned until the 2050s .