Children are exposed to a wide variety of pesticides originating from both outdoor and indoor sources. Several studies were conducted or funded by the EPA over the past decade to investigate children’s exposure to organophosphate and pyrethroid pesticides and the factors that impact their exposures. Urinary metabolite concentration measurements from these studies are consolidated here to identify trends, spatial and temporal patterns, and areas where further research is required. Namely, concentrations of the metabolites of chlorpyrifos (3,5,6-trichloro-2-pyridinol or TCPy), diazinon (2-isopropyl-6-methyl-4-pyrimidinol or IMP), and permethrin (3-phenoxybenzoic acid or 3-PBA) are presented. Information on the kinetic parameters describing absorption and elimination in humans is also presented to aid in interpretation. Metabolite concentrations varied more dramatically across studies for 3-PBA and IMP than for TCPy, with TCPy concentrations about an order of magnitude higher than the 3-PBA concentrations. Temporal variability was high for all metabolites with urinary 3-PBA concentrations slightly more consistent over time than the TCPy concentrations. Urinary biomarker levels provided only limited evidence of applications. The observed relationships between urinary metabolite levels and estimates of pesticide intake may be affected by differences in the contribution of each exposure route to total intake, which may vary with exposure intensity and across individuals.
This study evaluates the relationship of children's hygiene habits and food -handling behaviors on lead levels on hands and handled foods for toddlers living in lead -contaminated homes. Forty -eight inner city toddlers previously identified as having elevated blood lead levels participated in three consecutive days of designated food -handling activities. During the visits, duplicate diets were obtained, the child handled a banana, a hot dog, and had his / her hands wiped with a moist towelette. In addition, wipe samples were collected from the kitchen floor, and food items were deposited on and subsequently collected from the kitchen floor. All samples were analyzed for lead. The child's caregiver completed a questionnaire, which addressed the child's hygiene and eating behaviors. It was demonstrated that children's contact with residential dust containing lead can transfer lead to food. Both lead in the home and on the children's hands contribute to the contamination of food, and hence potential dietary exposure. Mean lead in handled bananas was 26 g / kg and on hot dogs 65 g / kg, and mean lead values on cheese and apple slices that had been on the floor were 119 and 215 g / kg. In addition, the child's hygiene habits as reported by the parent indicate that lack of basic hygiene patterns within a high lead environment can contribute to children's dietary exposure to lead.
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 g / 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 g Pb / day ) were more than three times the measured 24 -h duplicate -diet levels ( 8.37 g Pb/ day ) , which were almost six times higher than current national estimates ( 1.40 g 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. Journal of Exposure Analysis and Environmental Epidemiology ( 2000 ) 10, 723 ± 731.
To estimate pesticide exposure, urine samples are often needed to analyze pesticide metabolites. However, this is difficult for children wearing diapers because simple and feasible techniques suitable for field collection are not available. The objectives of this study were to test the validity of using cotton gauze pad as a medium for collecting urine samples from young children and to examine the stability of the recoveries for creatinine and pesticide metabolites over 24 h. Urine spiked with a pesticide and four metabolites, 2,4 -dichlorophenoxyacetic acid ( which is mainly eliminated from urine unchanged ) , 3 -phenoxybenzoic acid ( metabolite for synthetic pyrethroids ) , atrazine mercapturate ( metabolite for atrazine ) , malathion dicarboxylic acid ( metabolite for malathion ) , and 2 -isopropyl -4 -methyl -6 -hydroxypyrimidine ( metabolite for diazinon ) was added to the gauze pads and kept in jars at 378C in a water bath. Urine was expressed from the gauze pads immediately and after 1, 2, 4, 8, and 24 h, then analyzed. The recoveries, calculated as the percentage of concentration in expressed urine divided by that of the control urine sample, were within a range of 70 ± 130%. The metabolite and creatinine concentrations did not change with time in either expressed urine samples or controls. The results suggest that cotton gauze pad is a promising candidate for collecting urine samples from young children wearing diapers for studies in which these five urinary pesticide metabolites are to be analyzed. Journal of Exposure Analysis and Environmental Epidemiology ( 2000 ) 10, 703 ± 709.
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