Evolution of efficient methods to sample lead sources, such as house dust and hand dust, in the homes of children

257

235

In the summer of 1997, we measured the aggregate exposures of nine preschool children, aged 2-5 years, to a suite of organic pesticides and other persistent organic pollutants that are commonly found in the home and school environment. The children attended either of two child day care centers in the Raleigh-Durham-Chapel Hill area of North Carolina and were in day care at least 25 h/week. Over a 48-h period, we sampled indoor and outdoor air, play area soil and floor dust, as well as duplicate diets, hand surface wipes, and urine for each child at day care and at home. Our target analytes were several polycyclic aromatic hydrocarbons (PAH), organochlorine pesticides, and polychlorinated biphenyls (PCB); two organophosphate pesticides (chlorpyrifos and diazinon), the lawn herbicide 2,4-dichlorophenoxyacetic acid (2,4-D), three phenols (pentachlorophenol (PCP), nonyl phenols, and bisphenol-A), 3,5,6-trichloro-2-pyridinol (TCP), and two phthalate esters (benzylbutyl and dibutyl phthalate). In urine, our target analytes were hydroxy-PAH, TCP, 2,4-D, and PCP. To allow estimation of each child's aggregate exposures over the 48-h sampling period, we also used time-activity diaries, which were filled out by each child's teacher at day care and the parent or other primary caregiver at home. In addition, we collected detailed household information that related to potential sources of exposure, such as pesticide use or smoking habits, through questionnaires and field observation. We found that the indoor exposures were greater than those outdoors, that exposures at day care and at home were of similar magnitudes, and that diet contributed greatly to the exposures. The children's potential aggregate doses, calculated from our data, were generally well below established reference doses (RfDs) for those compounds for which RfDs are available.

Section: Discussionmentioning

confidence: 99%

Aggregate exposures of nine preschool children to persistent organic pollutants at day care and at home

Wilson

Chuang

Lyu

et al. 2003

257

235

“…Since lead dust is not cleaned effectively with a single wipe of the hands (Que Hee et al, 1985), it is likely that some combination of frequency and duration of mouthing behavior would lead to a most efficient ingestion pattern for lead contamination on the hands.…”

Section: Studies Of Oral Behaviors Using Video Methodsmentioning

confidence: 99%

Relationships of video assessments of touching and mouthing behaviors during outdoor play in urban residential yards to parental perceptions of child behaviors and blood lead levels

Schaefer

Vicario

et al. 2006

Childrens' touching and mouthing behaviors during outdoor play in urban residential yards were measured using video observations. Descriptions were made of childrens' outdoor residential play environments. Behaviors assessed were used to examine (1) validity of parental responses to questions on childrens' oral behaviors and outdoor play and (2) relationships of mouthing behaviors to blood lead levels (BLLs). Thirty-seven children aged 1-5 years were recruited for 2 h of video recording in their yard and blood lead measurement. Video assessments included hourly rates of hand touches to ground/ walking-level surfaces (cement/stone/steel, porch floor/steps, grass, and bare soil) and oral behaviors. Parental questionnaires assessed their child's outdoor activities, behaviors, and home environment. The children were: mean 39 months; 51% male; 89% Hispanic; and 78% Medicaid or uninsured. Twenty-two children had a blood lead measured (mean 6 mg/dl). During taping, all children had access to cement, 92% to grass, 73% to bare soil, and 59% to an open porch. Children had frequent touching and mouthing behaviors observed (median touches/h: touches to surfaces 81; hand-to-mouth area (with and without food) 26; hand-in-mouth 7; and object-in-mouth 17). Blood lead was directly correlated with log-transformed rates of hand-in-mouth (Pearson's correlation, r ¼ 0.564, n ¼ 22, P ¼ 0.006) and object-in-mouth (Pearson's correlation, r ¼ 0.482, n ¼ 22, P ¼ 0.023) behaviors. Parental questionnaire responses did not accurately reflect childrens' observed oral behaviors, play habits, or play environment. These data confirm the direct relationship between hand-to-mouth activities and BLLs and fail to validate parental perceptions of their child's mouthing behaviors or outdoor play environment.

“…Hand -to -mouth activities such as mouthing toys and sucking fingers or thumbs are associated with elevated blood lead in young children ( Charney et al, 1980;Bellinger et al, 1986;Baghurst et al, 1992;Langphear et al, 1996;Freeman et al, 1997 ). At the same time, lead levels on children's hands are associated with blood lead levels and with lead levels in homes and playgrounds (Charney et al, 1980;Angle et al, 1984;Bornschein et al, 1985;Que Hee et al, 1985;Thornton et al, 1990 ), and positive correlations exist between lead on children's hands, lead in the environment, and blood lead levels (Angle et al, 1984;Baghurst et al, 1992;Melnyk et al, 2000 ).…”

Section: Introductionmentioning

confidence: 99%

Contribution of children's activities to lead contamination of food

Freeman

Sheldon

Jimenez³

et al. 2001

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.