| Lead in Calcium Supplements Genine M. Scelfo and A. Russell Flegal Environmental Toxicology, University of California, Santa Cruz, California, USA Abstract
Intercalibrated measurements of lead in calcium supplements indicate the importance of rigorous analytical techniques to accurately quantify contaminant exposures in complex matrices. Without such techniques, measurements of lead concentrations in calcium supplements may be either erroneously low, by as much as 50%, or below the detection limit needed for new public health criteria. In this study, we determined the lead content of 136 brands of supplements that were purchased in 1996. The calcium in the products was derived from natural sources (bonemeal, dolomite, or oyster shell) or was synthesized and/or refined (chelated and nonchelated calcium) . The dried products were acid digested and analyzed for lead by high resolution-inductively coupled plasma-mass spectrometry. The method's limit of quantitation averaged 0.06 µg/g, with a coefficient of variation of 1.7% and a 90-100% lead recovery of a bonemeal standard reference material. Two-thirds of those calcium supplements failed to meet the 1999 California criteria for acceptable lead levels (1.5 µg/daily dose of calcium) in consumer products. The nonchelated synthesized and/or refined calcium products, specifically antacids and infant formulas, had the lowest lead concentrations, ranging from nondetectable to 2.9 µg Pb/g calcium, and had the largest proportion of brands meeting the new criteria (85% of the antacids and 100% of the infant formulas) . Key words: antacids, bonemeal, calcium supplements, dolomite, inductively coupled plasma-mass spectrometry (ICP-MS) , infant formulas, lead, nutritional supplements, oyster shell, vitamins. Environ Health Perspect 108:309-313 (2000) . [Online 21 February 2000] http://ehpnet1.niehs.nih.gov/docs/2000/108p309-313scelfo/ abstract.html Address correspondence to G. Scelfo, Environmental Toxicology, Applied Sciences 269, University of California, Santa Cruz, CA 95064 USA. Telephone: (831) 459-3563. Fax: (831) 459-2088. E-mail: gscelfo@es.ucsc.edu We thank S. Hibdon and R. Franks for analytical support. This research was partially supported by funds from the California Attorney General's Office, the Natural Resources Defense Council, and the University of California Toxic Substances Research and Teaching Program. Received 1 July 1999 ; accepted 26 October 1999.
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