Dietary exposure of children in lead-laden environments

Children are the most susceptible population to lead exposure because of three interacting factors; they have more opportunity for contact with lead sources due to their activities, lead absorption occurs more readily in a child compared to an adult, and the child's development is more vulnerable to lead than adults. Low levels of lead in the blood have been shown to cause adverse health effects; the level of concern for children is currently 10 microg/dl. The contribution of dietary exposure of lead to increased blood lead levels (PbB) is not well characterized. This study was conducted to measure potential dietary lead intakes of children 2 to 3 years of age who live in homes contaminated with environmental lead. Objectives were to estimate lead intakes for children consuming food in contaminated environments, recognizing unstructured eating patterns and to investigate if correlations exist between daily dietary exposure and measured PbB. Dietary exposure was evaluated by collecting samples that were typical of the foods the young children ate in their homes. A 24-h duplicate of all foods plus sentinel foods, i.e., individual items used to represent foods contaminated during handling, were collected from 48 children. Ten homes were revisited to obtain information on the variation in daily dietary intakes. Drinking water was evaluated both as part of the segregated beverage sample composite and by itself. Additional information collected included lead concentrations from hand wipes, floor wipes, and venous blood, and questionnaire responses from the caregiver on activities potentially related to exposure. Activities and hygiene practices of the children and contamination of foods in their environment influences total dietary intake. Estimated mean dietary intakes of lead (29.2 microg Pb/day) were more than three times the measured 24-h duplicate-diet levels (8.37 microg Pb/day), which were almost six times higher than current national estimates (1.40 microg Pb/day). Statistically significant correlations were observed between floor wipes and foods contacting contaminated surfaces, hand wipes and foods contacting contaminated hands and surfaces, and hand wipes and floor wipes. This study indicates that the dietary pathway of exposure to lead is impacted by eating activities of children living in lead-contaminated environments and that analysis of foods themselves is not enough to determine excess dietary exposures that are occurring.