Lake Onuma is a closed lake and has a limited amount of inflow and runoff water
Cesium-137 has a half-life of 30 years, longer than other radioactive materials.The lake water and pond smelt were measured for 5.4 years after the accident.Researchers looked at 137CS concentration in the lake's water and a fish native to the lake to come up with their findings.Right after the nuclear accident, 137CS concentration declined sharply, but that decline slowed in the months and years that followed.The researchers believe there will be a concentration of radioactive cesium-137 (137CS) for up to 10,000 days following the accident.
Scientists predict the lake near the devastating 2011 Fukushima nuclear accident will be radioactive for another 20 YEARS
