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P. Barry Ryan,¹ Kelly A. Scanlon,¹ and David L. MacIntosh²

¹Department of Environmental and Occupational Health, Rollins School of Public Health, Emory University, Atlanta, Georgia, USA
²Department of Environmental Health Science, College of Agricultural and Environmental Sciences, University of Georgia, Athens, Georgia, USA

Abstract

As part of a large pilot investigation of multimedia exposure to several classes of environmental contaminants, the National Human Exposure Assessment Survey (NHEXAS) -Maryland study, we collected 388 semiquantitative food checklists and duplicate diet solid food samples, analyzed for arsenic, cadmium, chromium, and lead concentrations, from 80 individuals in Maryland in 1995-1996 in a repeated measures design. Here we explore several methods to infer foods most strongly associated with concentrations of these metals observed in the duplicate diet in our data set. We employed two techniques in which logarithmically transformed metal concentrations in the duplicate diet were regressed on individual food item consumption using algorithms designed to identify the foods most associated with the observed duplicate diet concentrations. We also employed an alternative strategy in which foods to be used as independent variables in regression were selected using data collected in national food consumption and residue surveys, with regression procedures proceeding with the selected foods in a similar manner. The concordance of foods selected as major predictors among these three techniques is noteworthy and is discussed. Finally, the Dietary Exposure Potential Model (DEPM) was used with the Dietary Checklist data to predict duplicate diet concentrations within our sample. A comparison between the predicted values and those observed gave R² values of 0.180, 0.206, and 0.076 for As, Cd, and Pb, respectively (p < 0.0001 in all cases) . We discuss the significance of these observations and the implications for dietary-exposure-based risk analysis and dietary intake epidemiology. Key words: arsenic, cadmium, chromium, chronic exposure, dietary exposure, lead, NHEXAS-Maryland. Environ Health Perspect 109:121-128 (2001) . [Online 11 January 2001]

http://ehpnet1.niehs.nih.gov/docs/2001/109p121-128ryan/ abstract.html

Address correspondence to P.B. Ryan, Department of Environmental and Occupational Health, Rollins School of Public Health, Emory University, 1518 Clifton Road, Atlanta, GA 30322 USA. Telephone: (404) 727-3826. Fax: (404) 727-8744. E-mail: bryan@sph.emory.edu

This research was supported by the U.S. Environmental Protection Agency under cooperative agreement CR822038-1, the U.S. Department of Agriculture Hatch Project GEO00843, and the University of Georgia Research Foundation.

Received 18 July 2000 ; accepted 22 August 2000.