| Dietary Exposures to Selected Metals and Pesticides David L. MacIntosh, John D. Spengler, Halûk Özkaynak, Ling-hui Tsai, and P. Barry Ryan Environmental Science and Engineering Program, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02115 USA Abstract
Average daily dietary exposures to 11 contaminants were estimated for approximately 120,000 U.S. adults by combining data on annual diet, as measured by a food frequency questionnaire, with contaminant residue data for table-ready foods that were collected as part of the annual U.S. Food and Drug Administration Total Diet Study. The contaminants included in the analysis were four heavy metals (arsenic, cadmium, lead, mercury) , three organophosphate pesticides (chlorpyrifos, diazinon, malathion) , and four organochlorine pesticides (dieldrin, p,p´-DDE, lindane, heptachlor epoxide) . Dietary exposures to these contaminants were highly variable among individuals, spanning two to three orders of magnitude. Intraindividual exposures to the metals, organophosphates, and organochlorines were estimated to be strongly correlated ; Pearson's correlation coefficients ranged from 0.28 for lindane:dieldrin to 0.84 for lead:mercury. For some of the compounds (e.g., arsenic and dieldrin) , a substantial fraction of the population was estimated to have dietary intakes in excess of health-based standards established by the EPA. Before use for risk assessment or epidemiologic purposes, however, the validity of the exposure estimates must be evaluated by comparison with biological indicators of chronic exposure. Because of their low detection rate in table-ready foods, the estimated distributions of exposures for dieldrin, p,p´-DDE, heptachlor epoxide, lindane, diazinon, and chlorpyrifos were found to be sensitive to assumed values for nondetect samples. Reliable estimates of the population distribution of dietary exposures to most other contaminants cannot be made currently, due to their low rate of detection in table-ready foods. Monitoring programs that use more sensitive study designs and population-based assessments for other subpopulations should be a priority for future research. Key words: diet, epidemiology, exposure assessment, food frequency questionnaire, heavy metals, pesticides, Total Diet Study, uncertainty. Environ Health Perspect 104:202-209 (1996)
Address correspondence to D. L. MacIntosh, Rollins School of Public Health, Room 262, Emory University, 1518 Clifton Road NE, Atlanta, GA 30322 USA. We thank Walter Willett and Laura Sampson of the Department of Nutrition, Harvard School of Public Health, for access to the food consumption data and for excellent technical assistance, and John Evans and Paige Williams of the Harvard School of Public Health for their valuable reviews and comments. This research was supported by the U.S. Environmental Protection Agency under cooperative agreement no. CR822038-01. Received 19 August 1995 ; accepted 20 November 1995.
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