Levels of 90Sr and 137Cs in the urine of Finnish people

The aim of this study was to estimate the current concentrations of Sr-90 and Cs-137 in the urine of Finnish people and to estimate the doses. Two to three daily urine samples were collected from 18 adult Finnish volunteers in connection with studies of Cs-137 body burdens in 1999-2001. The Sr-90 activities in urine varied between 1.4 and 11 mBq 1(-1). The Cs-137 activity in urine varied between 0.36 and 56 Bq 1(-1). The daily urinary excretion was found to be 4.8-17 mBq for Sr-90 and 0.81-68 Bq for Cs-137. Assuming that the daily Sr-90 intake was constant and that 18% of the ingested activity was excreted in urine, the mean intake in the investigated group would vary between 27 and 96 mBq d(-1). Based on these estimated intake values, the respective annual effective internal doses from Sr-90 and Y-90 varied from 0.3 to 1.0 muSv and from (CS)-C-137 from 4 to 350 muSv during the sampling period.