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.

Serum levels of several organochlorine pesticides in farmers correspond with dietary exposure and local use history.

In response to reported increased cancer risks among farmers, the Agricultural Health Study (AHS) was designed to examine health outcomes and environmental exposures among farm families in the United States. In the pilot phase of the AHS, food, beverage, air, dermal, dust, surface wipe, and biological specimens (blood and urine) were collected and analyzed for six farm families in two states (IA and NC). In addition, questionnaires were administered to examine previous pesticide use. This paper reports the organochlorine pesticide results of the serum and dietary analyses as well as questionnaire results from the pilot exposure study of farmers and their families. Note, no organochlorine pesticides were reported as currently being applied to the study farms. In all human serum samples examined, typical U.S. population levels were found for the majority of the pesticides. In addition, human serum levels of organochlorine pesticides showed no significant daily or seasonal variation. However, serum trans-nonachlor levels were found to be higher in people living on the two farms in North Carolina than in people living on the four farms in Iowa (p < 0.05). Further, unusually high dieldrin levels were found in serum samples from a farmer and spouse living on an Iowa farm, and these levels were significantly higher than those of people living on the other farms (p < 0.05). Dieldrin was persistent in the foods consumed on the same Iowa farm where family members showed elevated serum levels. In addition, dietary samples from the North Carolina farms exhibited high levels of chlordane. No organochlorine pesticides were found in any of the drinking water samples. Dietary dieldrin levels on the same Iowa farm exceeded the oral reference dose (RfD) eight- to eleven-fold (50 ng/kg-day). No other pesticide exceeded the RfD. However, dietary chlordane levels at a North Carolina farm reached 17% of the RfD. Previous use of aldrin on an Iowa farm corresponded to dieldrin found in the diet and in the serum of the farmer and spouse. Previous reported use of chlordane on the North Carolina farms corresponded with measurable dietary levels of chlordance and higher serum trans-nonachlor levels than the levels in Iowa farm families.

Dietary exposure from pesticide application on farms in the Agricultural Health Pilot Study.

As part of total human exposure measurements performed on six farms in Iowa and North Carolina during the Agricultural Health Pilot Study, a household duplicate diet, several locally grown foods, an applicator meal, a child duplicate diet, and drinking water samples were collected. The pilot study was designed to test refined and newly developed protocols and analytical methods for collection and analyses of dietary samples to evaluate dietary exposure to farmers and their families in the household associated with current and former applications of pesticides. The household duplicate diet protocol was generally effective as a first step in measuring potential exposures of household members. The analytical methods used were capable of measuring 29 of the 33 targeted Agricultural Health Pilot Study pesticides in dietary samples. Collections were made during a pesticide nonapplication and application monitoring period. Pesticides in the foods and beverages of the participants were quantified at sub-ppb to 30-ppb levels in both the Iowa and North Carolina farms. Increased levels (20 ppb) of the pesticide being applied during the monitoring period were found in the applicator's meal. Dieldrin was persistent in the foods consumed on one Iowa farm. No pesticides were found in drinking water samples. The results show potential dietary exposures exceeding expected values exist to the farmers and their families for several of the pesticides in this study, particularly to those being applied and to the persistent pesticides in the environment.