Results from 2016 InFORM Biotic Monitoring – Shellfish and Vancouver Island Salmon

Results from 2016 shellfish monitoring show no 134-Cs or 137-Cs contamination in shellfish tissues.
Results from 2016 shellfish monitoring show no 134-Cs or 137-Cs contamination in shellfish tissues.

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.

Results from 2016 InFORM salmon monitoring as of October. More results will be added to this map as they become available.
Results from 2016 InFORM salmon monitoring as of November. More results will be added to this map as they become available.

Results from the first two salmon collection locations show a continued absence of Fukushima contamination after (6 hours on the detector). These first results represent twenty sockeye salmon, ten each from Nimpkish and Sproat Lakes on Vancouver Island. One fish from Sproat Lake did come back with levels of 137Cs near the minimum detectable concentration (MDC). Additional steps and spectrometer time will be necessary to determine if this level is attributed to Fukushima contamination or solely residual contamination due to atmospheric weapons testing. This additional processing is scheduled for after the initial sample runs are completed on all fish collected in 2016.

While only short times on the detector are needed for rather contaminated samples, a longer duration in the detector lowers the Minimum Detectable Concentration (MDC) and improves the statistics necessary to resolve lower levels of contamination.
While only short times on the detector are needed for rather contaminated samples, a longer duration in the detector lowers the Minimum Detectable Concentration (MDC) and improves the statistics necessary to resolve lower levels of contamination.

Lowering the MDC will improve the confidence for the concentrations of radionuclides that are present in the samples, similar to the way that zooming in with a camera allows you to take a picture with greater detail when objects are far away.

This year, results from the InFORM biotic monitoring project will be made public in smaller batches instead of all at once. This will mean results will become available more regularly.

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