This time, our tests barely detected minuscule, naturally-occurring traces of strontium-90 (Sr-90).
We tested our seafood three times before, looking for the radionuclides released in the greatest amounts from the Japanese nuclear plant: cesium-134, cesium-137, and iodine-131.
Every time, the tests found either no detectable levels, or amounts barely above the detectable levels, in completely safe concentrations normally found in wild seafood.
See "Vital Choice Fish Pass the Test with Flying Colors”, "Radiation Tests Clear Vital Choice Fish … Again”,and "Japan-Radiation Test Results - 3rd Round”.
Last summer, the first reports appeared suggesting that a longer-lived radionuclide called strontium 90 (Sr-90) was leaking from the stricken nuclear plant.
Sr-90 is an especially concerning radionuclide, so to ensure safety, we sent more fish to be tested for this radionuclide in the fall of 2013.
We've now received the results from SGS North America laboratories ... and they proved just as reassuring as our prior tests for cesium and iodine radionuclides.
Virtually no strontium 90 found
We sent samples of king salmon, sockeye salmon, and albacore tuna to SGS Laboratories to be tested for Sr-90.
We chose to test these species because they migrate the furthest west toward Japan ... usually more than one thousand miles east of the nuclear plants.
However, Sr-90 would be more concentrated in currents flowing from northeastern Japan (the area of the leaks) to the U.S. and Canadian West coasts, so testing for Sr-90 seemed prudent.
Strontium-90 test results
- Albacore tuna: 0.051 pCi/kg
- Sockeye salmon: 1.3 pCi/kg
- King salmon: 0.228 pCi/kg
These are truly minuscule, barely detectable traces that constitute extremely tiny percentages of the FDA’s strontium-90 safety limit (DIL) of 4,300 pCi/kg.
The fact that the levels found were so minuscule suggests that they are simply naturally occurring traces of this radionuclide.
By comparison, the concentration of strontium-90 in U.S.-grown vegetables typically peaks at 9 pCi/kg, which is thousands of times higher than the trace amounts detected in our fish.
Grains, leafy vegetables, and dairy products are the leading sources of dietary strontium-90 in the U.S.
The consensus scientific view has been that the radiation leaked from Japan poses no risks to consumers of seafood that (like our species) do not migrate close to Japan.
And our latest test results (available upon request), which detected virtually no Sr-90, support those expert scientific estimates.
Along with cesium-137, Sr-90 is one of the more dangerous radionuclides, because it has a long half-life of 30 years, and can accumulate in bone.
The main sources of Sr-90 in the ocean have been fallout from atmospheric nuclear tests in the 1950s and 1960s.
The Fukushima Dai-ichi accident and the amounts released from March to June, 2011 produced less than a one percent increase in ocean levels of this radioisotope.
- Universitat Autònoma de Barcelona. The Fukushima accident raised levels of radioactive strontium off the east coast of Japan by up to a hundred times. June 11, 2013 http://www.alphagalileo.org/ViewItem.aspx?ItemId=131949&CultureCode=en
- N.Casacuberta, P.Masqué, J.Garcia-Orellana, R.Garcia-Tenorio and K.O.Buesseler. Sr-90 and Sr-89 in seawater off Japan as a consequence of the Fukushima Dai-ichi nuclear accident. Biogeosciences. http://www.biogeosciences-discuss.net/10/2039/2013/bgd-1