Radiocesium body burdens in residents of northern Canada from 1963-1990.

Measurements of {sup 137}Cs body burdens in over 1,100 people from five northern Canadian communities were carried out with a portable whole body counting system during the winters of 1989 and 1990. These results are compared with over 3,000 similar measurements carried out during 1967-1969. Community mean body burdens and body concentrations had decreased by approximately a factor of 30 between the two survey periods. The dependence of body concentrations on the sex and age of the subjects has also changed significantly. This can be related to changes in the patterns of caribou consumption in the northern communities. Measurements of {sup 137}Cs in urine are also available for an earlier period (1963-1966) when world-wide fallout was at its highest level. A normalization procedure was developed to calculate the average radiocesium body concentration in each community from the concentration in urine. From data spanning a period of nearly 30 y (1963-1990), lifetime radiation doses have been estimated for most communities in the Yukon and Northwest Territories. These cumulative doses vary from 0.3 to nearly 40 mSv, with an Arctic-wide average of about 12 mSv. No health effects would be expected at these levels. 31 refs., 10 figs., 2 tabs.