A new report issued this week shows that Fukushima radiation contaminated West Coast’s waters. Sample collected have shown the highest level of radiation ever detected since the catastrophe. The level of cesium isotopes is 50 percent higher than other samples collected so far from nearby places.
However, the levels are still about 500 times lower than the safety limits set by the US government for drinking water and way below limits of swimming exposure.
A team of scientists, led by marine radiochemist Ken Buesseler are sampling Pacific waters looking for ocean-born radiation ever since three months after the Fukushima accident in 2011. Together with his colleagues, they have collected and analyzed almost 300 samples.
In 2014 he launched a citizen sampling effort called Our Radioactive Ocean (ORO) and he received funding from the National Science Foundation, which made possible the installation of sensors to look for radiation around the shore.
Buesseler’s findings are similar to those of other scientists, both from the group Kelp Watch and InFORM, from Canada. Unlike ORO, InFORM also samples marine organisms looking for traces of radiation. Though, no sign of cesium has been found in the fish collected near British Columbia.
However, almost all the water samples collected from the Pacific contain traces of cesium-137. This is a cesium isotope with a half-life of 30 years so traces left by nuclear testing from the 50s to the 70s are still visible.
Fukushima accident has released into the ocean both cesium-137 and cesium-137. To figure out the average quantity of cesium-137 the scientists measure the levels of cesium-134, with a half-life of only two years and they calculate that the amount of cesium-137 from Fukushima should be about the same.
Busseler is working with colleagues from Japan, continuing to monitor the continuous leaks from Fukushima by collecting sample from only half a mile away from the nuclear reactors. In October this year he went to Fukushima and collected samples of groundwater, ocean water, seafloor sediment and marine organisms from places near the nuclear power plants.
The radiation levels remain high (up to 100 times higher than on the US coast) in the ocean waters near Fukushima reactors, as radioactive elements are still leaking into the Pacific each day. Yet, the levels are thousands of times lower than at the time of the event, in 2011.
The scientists are still working to determine the levels of radiation released into the ocean each day.
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