Radiolead 210Pb and 210Po/210Pb activity ratios in calcium supplements and the assessment of their possible dose to consumers

This paper presents the results of pioneer study of the most popular calcium supplements as a potential additional source of radiolead Pb-210 in human diet. The analyzed calcium pharmaceutics contained organic or inorganic calcium compounds; some came from natural sources as mussels' shells, fish extracts, or sedimentary rocks. The idea was to investigate the naturally occurring Pb-210 activity in different calcium supplements and calculate the annual effective radiation dose from radiolead Pb-210 decay in consumed calcium supplement. The results showed Pb-210 concentrations in natural origin calcium supplements (especially sedimentary rocks) were significantly higher. The highest Pb-210 activity concentrations were determined in mineral tablets made from dolomite -2.97 +/- 0.18 mBq g(-1), while the lowest was observed in organic calcium compounds - both calcium lactate -0.08 +/- 0.01 and 0.13 +/- 0.01 mBq g(-1). The highest annual radiation dose from Pb-210 taken with 1 tablet of calcium supplement per day was calculated for soluble calcium lactate sample -1.19 +/- 0.03 mu Sv year(-1), while the highest annual radiation dose from Pb-210 taken daily with 1 g of pure Ca for dolomite -5.57 +/- 0.34 mu Sv year(-1).