[en] Water samples were analyzed for total U, Ra-226, Cs-137, Sb-125 and tritium. Levels are generally low, and no time trends were discernible during the monitoring period. Temporal variations among the quarterly analyses are mostly insignificant. Except for total U at certain locations, all other radionuclide levels were much below the 'target concentration' guidelines for Canadian drinking water. The main contribution to the radiological dose commitment was from total U and Ra-226. Contributions from individual radionuclides to cumulative dose were in the order: total U > Ra-226 > tritium > Cs-137 > Sb-125. The limited sediment data suggest that the nuclear facilities along the Ottawa River have increased the levels of Cs-137 and Co-60 but have not affected those of Pb-210 and Ra-226. Total U and Ra-226 activities data suggest disequilibrium; the levels of total U in water were much higher than those of Ra-226. Concentrations of the two radionuclides, however, were positively correlated for most surface waters

[en] The gastrointestinal (GI) absorption factors and the biological retention times for polonium were determined for a group of 14 volunteers - seven men and seven women - from Saskatoon, Saskatchewan, Canada. Each volunteer consumed 2.0 kg of caribou meat containing known amounts of naturally occurring ²¹⁰Po. Urine and faecal samples were collected for up to 65 days after meat consumption and analysed for ²¹⁰Po. The average GI absorption factor for the 14 volunteers was 56±4% (range = 31-71%), not significantly different from the ICRP value of 50%. About 3% of absorbed polonium underwent prompt excretion by the urinary pathway. The remainder was retained by the body with a half-time >100 days, compared to the ICRP value of 50 days. The effect of these findings increases the dose estimate for ingestion of ²¹⁰Po in food by a factor of 1.5 to 3.5. Thus, background doses to people consuming caribou and reindeer may be higher than previously thought. (author)

[en] In 1978, AECL was mandated by the government of Ontario and the federal government to find a permanent disposal solution for spent nuclear fuels. Canada opted for disposal in plutonic rocks of the Canadian shield. The Canadian concept calls for disposal in crystalline rocks at a depth of 500 to 1000 m below the surface. The spent fuel would be contained in a canister, the canister would be emplaced in a vault containing clay-based buffer materials, and the cavity would be backfilled and sealed with natural materials. A Federal Environmental Assessment Review Panel was formed in 1992 to assess the concept for disposal of the spent fuel. In this paper a brief discussion of the human health impacts of the proposed concept is presented. Our assessment is based on the information provided by AECL, namely, the main EIS document, a summary and nine other supporting documents

[en] Short communication