More results from InFORM’s 2016 biotic monitoring results are now available and reveal that Fukushima contamination was not detected in sampled BC salmon after initial testing. These results are an update to the earlier report on the first 20 of the 123 fish donated by First Nations from 10 rivers in British Columbia and Yukon in 2016. Nine fish did have individual levels of 137Cs detected near the minimum detectable concentration (MDC). These levels (<0.7 Bq kg-1) are not known to present a significant health risk and are ~1,400x lower than the national and international action level (1000 Bq kg-1). For perspective, you would need to consume 1000-1500 kg of salmon at this concentration of cesium to receive the same radiation dose acquired during a single cross country flight. There has not been a significant increase to the total 137Cs concentration in BC salmon since InFORM monitoring began in 2014.
Results from the shellfish meat and first 20 salmon samples collected in 2016 reveal an absence of Fukushima radiation. Shellfish from four species were collected from many of British Columbia’s major shellfish aquaculture regions from Prince Rupert to the Sunshine Coast and Vancouver Island. These results are from just the meat of the shellfish and additional analysis of the crushed shell is currently ongoing. The four types of molluscs (Pacific Scallop (Patinopecten yessoensis), Pacific Oyster (Crassostrea gigas), Northern Blue Mussel (Mytilus edulis and a hybrid with M. galloprovincalis), and Manila Clam (Venerupis philippinarum)) were chosen for analysis because previous work in other tropical species has shown that bivalves bioaccumulate cesium at rates faster than many other organisms. This work on tropical species did find that much of the cesium contamination was located in the shell so we await the results of the ongoing shell analyses. The absence of contamination in the edible meat from any of the species is reassurance to the $25 million aquaculture industry of BC that their product is safe to send to market and safe for human consumption. Continue reading Results from 2016 InFORM Biotic Monitoring – Shellfish and Vancouver Island Salmon
For the first time, the Fukushima fingerprint isotope, cesium-134 (134Cs; half-life ~ 2 years), has been detected at an extremely low level in a Canadian salmon by the InFORM project. The single sockeye salmon that tested positive was sampled from Osoyoos Lake in the summer of 2015, according to scientists from the Radiation Protection Bureau at Health Canada, in cooperation with Fisheries and Oceans Canada and local First Nations. The sample was one of a few (8 out of 156 total) individual fish that had trace levels of the longer lived cesium-137 (137Cs) (30 yr half-life) that we reported on last winter. To determine if this trace 137Cs was from Fukushima or remnant from atmospheric weapons testing, InFORM reexamined these individual fish samples to see if extremely low levels of 134Cs may be present. The results of this extended analysis show that trace (0.07 Bq kg-1) levels of 134Cs were detected in one sample from Okanagan/Columbia River population. No 134Cs was detectable in the other samples. The observed levels remain well below the action level (1000 Bq kg-1) set by Health Canada guidelines. Continue reading Pushing the Limit: Fukushima Fingerprint Isotope Found in Salmon from 2015