BACKGROUND RADIOACTIVITY LEVELS IN CANADIAN GRAINS AND OIL SEEDS

A study has been carried out to determine the levels of radioisotopes in five Canadian grains From pre(1985) and post-Chernobyl (1986) crop years. In addition, the radioisotope levels were determined in grains from the 1988 crop year consisting of wheats, oats, barley, corn and o il seeds which included flax, sunflower and canola The grain and oil-s eed samples were ashed to reduce their volume, and the gamma-emitters Cs-137 and K-40 were determined using a high-purity germanium detector and a high-purity germanium well detector. The Sr-90 activity measure ments required further ashing of the samples followed by chemical sepa rations and beta-counting of the separated daughter Y-90. The results for the 1985, 1986 and 1988 crop years are discussed and compared with results from grain crops obtained during years of atmospheric bomb te sts in the 1950's.