Project Overview for Canadian National Science Fair

Is Radioactively Contaminated Seafood Being Sold in Canadian Grocery Stores? 

Bronwyn Delacruz, Intermediate, GP Composite High School, Alberta, Canada


Click to download and view full size two page presentation.

Introduction: For the past 3 years, 400 tons/day of radioactively contaminated water has been spilling into the Pacific from 4 damaged Fukushima reactors. This is arguably the world’s greatest oceanic environmental health challenge of our lifetime. The Canadian Food Inspection Agency (CFIA) stopped radiation testing in October 2012; it is hypothesized that contaminated food is entering the Canadian food supply undetected.

Methods: Four experiments were conducted to test this hypothesis. The 1st experiment involved identifying the most significant variables and controlling them to optimize a Geiger counter’s ability to detect radiation in food. The 2nd experiment involved screening seafood (fish, shellfish, edible seaweed) purchased in grocery stores to determine radioactivity. With this information a controlled, blinded, randomized experiment was designed for the remaining studies. The 3rd experiment assessed whether there was a change post-Fukushima in radioactivity of nori seaweed standardized for weight from the same country. The 4th experiment determined if there was radioactivity in kelp that exceeded 0.5Bq/cm2 or double background which is considered the “actionable threshold“ for surface radioactive contamination. Test for statistical significance was performed using Welch’s T test for unequal variances and a Quantile test, along with a Dixon’s test to examine and treat potential outliers.

Results: It was determined that the ideal weight was 5g or less and that the sample be no larger than the Geiger counter win-dow. The sample is best tested with the Geiger counter window as close to the sample as possible; <1mm separated by plastic to prevent contamination. Little improvement was shown using water and double steel wall shielding versus only single steel wall shielding. Dehydrated samples were ideal for testing with nearly double the radioactive readings then when the samples were (re) hydrated. Of all the seafoods tested (N>600), Kelp was shown to have the most radioactivity. Post-Fukushima readings in Nori seaweed were elevated compared to Pre-Fukushima (p<0.01) possibly linking the effects of nuclear contamination on marine bio-ta in the region. Using the double background criteria where Eastern Pacific kelp was used as uncontaminated background, 5 Chinese and 1 Korean sample exceeded double background (p<0.0001) indicating the presence of radioactive contamination in Western Pacific Kelp. Exceeding the level of 0.5 Bq/cm2 for actionable radioactive contamination, 6 Chinese and 1 Korean Kelp sample were found to be above this level and thus were deemed to be radioactively contaminated.

Conclusion: Radioactively contaminated food is entering Canada and being sold undetected. Urgent attention is needed by the CFIA for further study. But with no additional testing planned by the CFIA at this time, it is up to individual citizens to remain vigi-lant. The data compels us to screen our food independently, spearhead the development of an international collaborative effort of data acquisition and sharing through an open source database, petition the government to restart the CFIA’s enhanced testing program as well as to petition our government to assist Japan in their containment efforts before it is too late.