Skip common site navigation and headers
United States Environmental Protection Agency
Exposure Research
Begin Hierarchical Links EPA Home > Research & Development > Exposure Research > Publications/Presentations > End Hierarchical Links

 

Use of Pharmacokinetic Model to Assess Chlorpyrifos Exposure and Dose in Children Based on Urinary Biomarker Measurements

spacer
spacer
Abstract: Chlorpyrifos is a common agricultural insecticide and has been used residentially in the United States until 2000 when this use was restricted by the U.S. Environmental Protection Agency (U.S. EPA). A chlorpyrifos metabolite, 3,5,6-trichloro-2-pyridinol (TCPy) has been found in urine samples collected during exposure field studies. In this work, we use urinary biomarker data and the inverse solution of a simple pharmacokinetic (PK) model for chlorpyrifos to estimate the magnitude and timing of doses. Three urine samples were collected on separate days from each of 15 children (Ages 3 - 12) who were participants in the Minnesota Children Pesticide Exposure Study (MNCPES). The total volume of urine was noted and samples analyzed for TCPy. The urinary data was used along with constraints imposed on dose timing based on responses of the individuals to pesticide-use surveys. We predict the time and magnitude of multiple "event" exposures characterized by short-term relatively high doses superimposed over a continuous background exposure. The average dose of chlorpyrifos predicted by the model was 1.61 ug/kg per reported event. Average background dose rate for these children that reported exposure events was 0.0062 ug/kg/h, or 0.15 ug/kg/day. In addition to predicting the total dose of chlorpyrifos received by an individual from urinary biomarker measurements, the model can then be run in a forward manner once the exposure regime is determined. This will allow the prediction of the total amount of TCPy eliminated in the urine over any time period of interest.

The U.S. Environmental Protection Agency through its Office of Research and Development funded the research described here. It has been subject to Agency review and approved for publication. Mention of trade names or commercial products does not constitute an endorsement or recommendation for use.
spacer
Citation:Rigas, M. L., M. S. Okino, and J. J. Quackenboss. Use of Pharmacokinetic Model to Assess Chlorpyrifos Exposure and Dose in Children Based on Urinary Biomarker Measurements. TOXICOLOGICAL SCIENCES 61(0):374-381, (2001).
spacer
spacer
Contact: Liz Hope - (919) 541-2785 or hope.elizabeth@epa.gov
spacer
Division: Human Exposure & Atmospheric Sciences Division
spacer
Branch: Human Expsoure Research Branch
spacer
Product Type: Journal
spacer
Published: 09/17/2001
spacer
Related Entries:
spacer
Bullet Item Analysis of NHEXAS Data from the Children's Pesticide Exposure Study in Minnesota
spacer Relationship Reason:   A Project of the Product
spacer
spacer
spacer

 

ORD Home | Search EPA | Search NERL | Search EIMS | Contacts | Help

 
Begin Site Footer

EPA Home | Privacy and Security Notice | Contact Us

Last Updated on Monday, October 22, 2007
URL: http://cfpub.epa.gov