Parts of the sampled kelp. Photos courtesy of CSULB.
In the first of three study sampling periods completed for Kelp Watch 2014, Cal State Long Beach (CSULB) researchers have announced that no ocean-borne Fukushima radioactivity has made it to our shoreline.
“Our research indicates that these are not considered—at all—human health risk levels,” said Kelp Watch leader and CSULB Dr. Steve Manley. “You can go swimming in the water and eat local fish without any major problem.”
CSULB, which partnered with fellow researchers at Lawrence Berkeley National Laboratory, announced the Kelp Watch program back in February. 42 sites—from Kodiak to Baja California—that are home to Giant Kelp (Macrocystis) and Bull Kelp (Nereocystis) have been selected to research, with the first sample coming from 38 of those sites.
Two additional sites in Hawaii and Guam were also studied though not for their kelp but their brown algae, since kelp doesn’t grow in these regions. Additionally, Chile, home of the Giant Kelp, will act as a reference point since it is considered a “Fukushima-free” site that is removed entirely from the possible effects of the fallout.
The Tōhoku earthquake—the fifth most powerful earthquake in recorded history—and its subsequent tsunami in March of 2011 caused a catastrophic structural failure at the Fukushima I Nuclear Power Plant. Once the tsunami hit, the plant began released radioactive materials into the Pacific Ocean in two ways: through the sea water that was used to keep the reactors cool and through broken plumbing.
“A lot of radioactive material was released into the ocean,” said Manley. “It then began its long travel to the West Coast. But in the time that it was dispersed, both horizontally and vertically, many of the radioactive isotopes—particularly those of the short-lived variety—have decayed away. Plus, during that trip, there’s been a lot of mixing: the concentration of radioactive isotopes in the seawater has been dramatically reduced and diluted.”
Even though models projected that a very little amount of radioactivity would hit our shores, Manley and researchers feel it is nonetheless important to know when and if they do arrive at North America.
Two “signature” isotopes came out of Fukushima: Cesium-134 and Cesium-137. While Cs-137 was detected, the lack of Cs-134 found in conjunction with the Cs-137 isotopes leads Manley et. al. to believe that the Cs-137 found is the lingering effect of nuclear weapons testing conducted in the 1950s and 60s.
The results of the second sampling will be released mid-summer while the results of the third and final sampling will be released during late fall.
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