Cumulative organophosphate pesticide exposure and risk assessment among pregnant women living in an agricultural community: a case study from the CHAMACOS cohort.

Fleas are a persistent problem for pets that require implementation of control measures. Consequently, pesticide use by homeowners for flea control is common and may increase pesticide exposure for adults and children. Fifty-five pet dogs (23 in study 1; 22 in study 2) of different breeds and weights were treated with over-the-counter flea collars containing tetrachlorvinphos (TCVP). During study 1, fur of treated dogs was monitored for transferable TCVP residues using cotton gloves to pet the dogs during 5-min rubbings post-collar application. Plasma cholinesterase (ChE) activity was also measured in treated dogs. Average amounts of TCVP transferred from the fur of the neck (rubbing over the collar) and from the back to gloves at 3 days post-collar application were 23,700 ± 2100 and 260 ± 50 mg/glove, respectively. No inhibition of plasma ChE was observed. During study 2, transferable TCVP residues to cotton gloves were monitored during 5-min rubbings post-collar application. Transferable residues were also monitored on cotton tee shirts worn by children and in the first morning urine samples obtained from adults and children. Average amounts of TCVP transferred to gloves at 5 days post-collar application from the neck (over the collar) and from the back were 22,400 ± 2900 and 80 ± 20 mg/glove, respectively. Tee shirts worn by children on days 7-11 contained 1.8 ± 0.8 mg TCVP/g shirt. No significant differences were observed between adults and children in urinary 2,4,5-trichloromandelic acid (TCMA) levels; however, all TCMA residues (adults and children) were significantly greater than pretreatment concentrations (a ¼ 0.05). The lack of ChE inhibition in dogs and the low acute toxicity level of TCVP (rat oral LD 50 of 4-5 g/kg) strongly suggest that TCVP is rapidly detoxified and excreted and therefore poses a very low toxicological risk, despite these high residues.

Section: Introductionmentioning

confidence: 99%

Assessing intermittent pesticide exposure from flea control collars containing the organophosphorus insecticide tetrachlorvinphos

Davis

Boone

Moran

et al. 2008

“…Research has shown that children can be exposed to pesticides from numerous sources such as carpet, clothing, house dust and toys in treated houses (Fenske et al, 1990;Castorina et al, 2003;Colt et al, 2003;Rohrer et al, 2003;Hore et al, 2005). Pesticide exposures have also been documented from children who played outside in treated lawns and/or gardens (Woody, 1984;Morgan et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Assessing transferable residues from intermittent exposure to flea control collars containing the organophosphate insecticide chlorpyrifos

Chambers

Boone

Davis

et al. 2007

Children can be exposed to pesticides from numerous residential sources such as carpet, house dust, toys and clothing from treated homes, and flea control remedies on pets. In the present studies, 48 pet dogs (24 in each of two studies) of different breeds and weights were treated with over-the-counter flea collars containing chlorpyrifos (CP), an organophosphorus insecticide. Transferable insecticide residues were quantified on cotton gloves used to rub the dogs for 5 min and on cotton tee shirts worn by a child (Study 2 only). First morning urine samples were also obtained from adults and children in both studies for metabolite (3,5,6-trichloro-2-pyridinol) quantification. Blood samples were obtained from treated dogs in Study 1 and plasma cholinesterase (ChE) activity was monitored. Transferable residues on gloves for all compounds were highest near the neck of the dogs and were lowest in areas most distant from the neck. Rubbing samples (over the collar) at two weeks post-collar application contained 447757 mg CP/glove while samples from the fur of the back contained 872 mg CP/glove. In Study 2, cotton tee shirts worn by children at 15 days post-collar application for 4 h showed CP levels of 134766 ng/g shirt. There were significant differences between adults and children in the levels of urinary metabolites with children generally having higher urinary levels of metabolites than adults (grand mean7SE; 11.671.1 and 7.970.74 ng/mg creatinine for children and adults, respectively, compared to 9.470.8 and 6.970.5 ng/mg creatinine before collar placement). Therefore, there was little evidence that the use of this flea collar contributed to enhanced CP exposure of either children or adults.

“…Through the National Human Exposure Assessment Survey (NHEXAS) (Sexton et al, 1995), the Children's Total Exposure to Persistent Pesticides and other Persistent Organic Pollutants (CTEPP) (USEPA, 2002), and other programs, the US EPA is developing databases on exposures of human populations to a wide range of pollutants in air, water, food, soil, and indoor/residential environments, and over a wide range of space and time scales. The University of California, Berkeley Center for the Health Assessment of Mothers and Children of Salinas (CHAMACOS) is collecting biomarkers in farming communities for pesticides and other important pollutants from mothers and their newborn children from conception through early childhood (Castorina et al, 2002).…”

Section: Introductionmentioning

confidence: 99%

Reconstructing population exposures from dose biomarkers: inhalation of trichloroethylene (TCE) as a case study

Sohn

McKone

Blancato

2004

Self Cite

Physiologically based pharmacokinetic (PBPK) modeling is a well-established toxicological tool designed to relate exposure to a target tissue dose. The emergence of federal and state programs for environmental health tracking and the availability of exposure monitoring through biomarkers creates the opportunity to apply PBPK models to estimate exposures to environmental contaminants from urine, blood, and tissue samples. However, reconstructing exposures for large populations is complicated by often having too few biomarker samples, large uncertainties about exposures, and large interindividual variability. In this paper, we use an illustrative case study to identify some of these difficulties, and for a process for confronting them by reconstructing population-scale exposures using Bayesian inference. The application consists of interpreting biomarker data from eight adult males with controlled exposures to trichloroethylene (TCE) as if the biomarkers were random samples from a large population with unknown exposure conditions. The TCE concentrations in blood from the individuals fell into two distinctly different groups even though the individuals were simultaneously in a single exposure chamber. We successfully reconstructed the exposure scenarios for both subgroups F although the reconstruction of one subgroup is different than what is believed to be the true experimental conditions. We were however unable to predict with high certainty the concentration of TCE in air.