Paromita Hore

Contributions of children's activities to pesticide hand loadings following residential pesticide application

The role of childrens activities in leading to pesticide exposure was evaluated by comparing pesticide loadings on the hands of children with the activities of the same children observed over a 4-h period. In all, 10 children ranging in age from 24 to 55 months were videotaped on the second day following a routine professional crack and crevice chlorpyrifos application in their homes. Before and following the video session, the childrens hands were rinsed in isopropyl alcohol. Thus, only the chlorpyrifos that accumulated on and remained on the childs hands during the videotaping were removed for analysis after the videotaping session. The rinsate was analyzed for chlorpyrifos. The childrens behaviors were quantified using virtual tracking device and the frequency and duration of behaviors, the hourly rate of behaviors, and the locations in which behaviors occurred were compared to hand loadings of pesticides. Pesticide hand loadings obtained following the videotaping sessions were associated with pesticide levels on surfaces and toys, but not with air levels. Pesticide loadings obtained following the videotaping sessions were also associated with frequencies, durations, and hourly rates of contact with bottles, and object-to-mouth behaviors, as well as contact duration with upholstered/textured surfaces. The hand loadings were also associated with the number of locations where the children exhibited object-to-mouth behavior and with childrens use of house space during the videotaping sessions.

Chlorpyrifos Accumulation Patterns for Child-Accessible Surfaces and Objects and Urinary Metabolite Excretion by Children for 2 Weeks after Crack-and-Crevice Application

The Children’s Post-Pesticide Application Exposure Study (CPPAES) was conducted to look at the distribution of chlorpyrifos within a home environment for 2 weeks after a routine professional crack-and-crevice application and to determine the amount of the chlorpyrifos that is absorbed by a child living within the home. Ten residential homes with a 2- to 5-year-old child in each were selected for study, and the homes were treated with chlorpyrifos. Pesticide measurements were made from the indoor air, indoor surfaces, and plush toys. In addition, periodic morning urine samples were collected from each of the children throughout the 2-week period. We analyzed the urine samples for 3,5,6-trichloropyridinol, the primary urinary metabolite of chlorpyrifos, and used the results to estimate the children’s absorbed dose. Average chlorpyrifos levels in the indoor air and surfaces were 26 (pretreatment)/120 (posttreatment) ng/m3 and 0.48 (pretreatment)/2.8 (posttreatment) ng/cm2, respectively, reaching peak levels between days 0 and 2; subsequently, concentrations decreased throughout the 2-week period. Chlorpyrifos in/on the plush toys ranged from 7.3 to 1,949 ng/toy postapplication, with concentrations increasing throughout the 2-week period, demonstrating a cumulative adsorption/absorption process indoors. The daily amount of chlorpyrifos estimated to be absorbed by the CPPAES children postapplication ranged from 0.04 to 4.8 μg/kg/day. During the 2 weeks after the crack-and-crevice application, there was no significant increase in the amount of chlorpyrifos absorbed by the CPPAES children.

Phthalates Biomarker Identification and Exposure Estimates in a Population of Pregnant Women

ABSTRACT Phthalates are known reproductive and developmental toxicants in experimental animals. However, in humans, there are few data on the exposure of pregnant women that can be used to assess the potential developmental exposure experienced by the fetus. We measured several phthalate metabolites in maternal urine, maternal serum, and cord serum samples collected at the time of delivery from 150 pregnant women from central New Jersey. The urinary concentrations of most metabolites were comparable to or less than among the U.S. general population, except for mono(2-ethylhexyl) phthalate (MEHP), mono(2-ethyl-5-hydroxyhexyl) phthalate (MEHHP), and mono(2-ethyl-5-oxohexyl) phthalate (MEOHP), three metabolites of di(2-ethylhexyl) phthalate (DEHP). The median urinary concentrations of MEHHP (109 μ g/l) and MEOHP (95.1 μ g/l) were more than 5 times their population-based concentrations, whereas the median urinary concentration of MEHP was more than 20 times higher. High concentration of MEHP may indicate a recent exposure to the parent chemical DEHP in the hospital shortly before the collection of the samples. Calculation of daily intakes using the urinary biomarker data reveals that none of the pregnant women tested had integrated exposures to DEHP greater than the Agency for Toxic Substances and Disease Registrys minimal risk levels (MRLs chronic 60, intermediate 100 μ g/kg/day). No abnormal birth outcomes (e.g., birth weight, Apgar Score, and gestational age) were noted in those newborns whose mothers had relatively greater exposure to DEHP during the perinatal period than others in this study. Significantly greater concentrations and detection frequencies in maternal urine than in maternal serum and cord serum suggest that the urinary concentrations of the phthalate metabolites may be more reliable biomarkers of exposure than their concentrations in other biological specimens.

Biological Monitoring of Organophosphate Pesticides in Preschool Children in an Agricultural Community in Thailand

Abstract Organophosphate pesticide exposures of preschool children in a Thailand agricultural community and reference children living outside the farm area in the same subdistrict were determined. Levels of dialkylphosphate (DAP) metabolites were measured in first-morning-void urine samples. During the dry season (April-May), the farm children excreted significantly igher levels of all DAP metabolites than the reference children did (Mann-Whitney U test, p < 0.05; Wilcoxon signed-rank text, p < 0.05). During the wet season (September-October), DAP metabolite levels were similar in the two groups. Reference children showed no significant difference related to season. Pesticide spraying during the dry season is a likely cause of the farm childrens organophosphate exposures.

Pesticide Concentrations in Matrices Collected in the Perinatal Period in a Population of Pregnant Women and Newborns in New Jersey, USA

ABSTRACT Gestational exposure to pesticides may adversely affect fetal development and birth outcomes. However, data on fetal exposure and associated health effects in newborns remain sparse. We measured a variety of pesticides and metabolites in maternal urine, maternal serum, cord serum, amniotic fluid, and meconium samples collected at the time of cesarean delivery from 150 women in central New Jersey, USA. Women who used pesticides at home had higher concentrations of pesticides or metabolites in cord serum [e.g., dacthal (p = .007), diethyltoluamide (p = .043), and phthalimide (p = .030)] than those who did not use pesticides, suggesting that residential use of pesticides may contribute to overall exposure as assessed by biomonitoring. Except for orthophenylphenol, the concentrations of most pesticides in biological matrices of this study population were either comparable to or lower than the levels reported in previous studies and in the U.S. general population. The daily exposure estimates of two representative organophosphorus insecticides (chlorpyrifos and diazinon) were lower than most regulatory protection limits (USEPA oral benchmark dose10/100, USEPA reference oral dose, or ATSDR minimal risk levels); however, they were near or at the USEPAs population-adjusted doses for children and women. No abnormal birth outcomes or other clinical endpoints were noted in those newborns who had higher concentrations of orthophenylphenol during the perinatal period.

Analytical Method Developed for Measurement of Dialkylphosphate Metabolites in Urine Collected from Children Non-Occupationally Exposed to Organophosphate Pesticides in an Agricultural Community in Thailand

There has been increasing concern in regards to organophosphate (OP) pesticide exposure among farm workers and their families in Thailand’s agricultural areas. Therefore, the development of an analytical method for estimating OP pesticide exposure is necessary to allow for monitoring of OP pesticide exposures within these populations. This paper describes an analytical method developed to measure dialkylphosphate (DAP) metabolites in urine. The methods in this study are important in the biological monitoring of OP metabolites in agricultural families in Thailand and can be used as an initial guidance procedure in any environmental toxicological laboratory in Thailand.

Organophosphate Pesticide Exposures of Traditional and Integrated Pest Management Farmers from Working Air Conditions: A Case Study in Thailand

Abstract Concentrations of organophosphate pesticides, including chlorpyrifos and methyl parathion, were measured in ambient air breathed by farmers in Tambon Bang Rieng, Thailand. An exposure assessment and comparison was made between the levels of pesticide exposure of traditional and integrated pest management (IPM) farmers. Thirty-three air samples were collected during pesticide spraying. Traditional farmers were exposed to higher levels of the pesticide(s), with an average concentration of 0.19 mg/m3, compared with 0.037 mg/ m3 for the IPM farmers. It was estimated that a farmer of Tambon, Bang Rieng would be exposed to 81–12,261 mg of the organophosphate pesticide(s) via inhalation throughout his or her lifetime. Moreover, traditional farmers absorbed more of pesticide via inhalation than did IPM farmers.

Using observational information in planning and implementation of field studies with children as subjects.

Children have been one of the least-studied populations for estimating environmental exposure, even though they are cited as a sensitive subgroup for diseases derived from environmental exposure. This trend appears to be changing as more studies are conducted with children as subjects. It consequently becomes increasingly important to gather and use observational data in all phases of the study. Observational data are the key for both defining the pathway of exposure and for assessing effectiveness of the data-collection protocols. Obtaining quality data from a study involving children requires: efficient use of observational data, collection of meaningful personal and microenvironmental samples, linkage of observational data to the collected samples, and personnel trained to work with children using pilot-tested protocols. Although all of these help to ensure the quality of the data, the utility of the data is often determined by observational feedback from those who collected it. Laboratory-derived protocols should be living documents and observations from the field should be used to modify the data-collection methods when practical.