Food ingestion doses from artificial radionuclides in Cumbrian diets, ten years post-Chernobyl

The ingestion of radioactively contaminated foodstuffs is a major pathway o f radiation exposure in humans. A duplicate diet approach has been used to assess ingestion doses of the local population of west Cumbria in the Unite d Kingdom. There has been historical interest in this population group, par ticularly those living close to the Sellafield nuclear installation, and th e two major routes of ingestion exposure for them, namely the consumption o f either local agricultural produce (the terrestrial pathway) or of locally derived sea foods (the marine pathway). We examine here the ingestion dose s derived using radionuclide data from duplicate diet studies carried out d uring 1986, 1995 and 1996. The Chernobyl accident occurred during sample co llection for the first survey; the latter surveys thus provide data to eval uate any changes in the ingestion dose up to 10 years after the accident. T he contribution of Chernobyl fallout to the dose in 1986 was mainly due to radiocaesium (Cs-134 and Cs-137); in 1996, the Cs-137 results are comparabl e to those obtained during the 1986 pre-Chernobyl survey, suggesting that r adiocaesium activity concentrations in local foods from around west Cumbria have now decreased to pre-Chernobyl levels. The contributions of other art ificial radionuclides (Sr-90, Pu239 + 240, C-14) analysed in the diet sampl es over the period are also assessed. Carbon-14, measured in the 1995 and 1 996 surveys but not in 1986, is currently the most important contributor to the dose; in 1996, it accounted for at least 75% of the total ingestion do se from the radionuclides measured. (C) 1999 Elsevier Science Ltd. All righ ts reserved.