Saliva Bio-monitoring for Organophosphorus Pesticide Exposures in Children

EPA Grant Number: R828606
Title: Saliva Bio-monitoring for Organophosphorus Pesticide Exposures in Children
Investigators: Fenske, Richard , Lu, Chun
Current Investigators: Fenske, Richard , Barr, Dana Boyd , Lu, Chensheng (Alex) , Rodriguez, Teresa
Institution: University of Washington - Seattle
Current Institution: University of Washington - Seattle , Centers for Disease Control and Prevention , Emory University , Universidad Nacional Autónoma de Nicaragua–León
EPA Project Officer: Laessig, Susan A.
Project Period: September 1, 2000 through August 31, 2003 (Extended to August 31, 2005)
Project Amount: $742,597
RFA: Biomarkers for the Assessment of Exposure and Toxicity in Children (2000) RFA Text |  Recipients Lists
Research Category: Children's Health , Health Effects , Human Health , Health

Description:

The primary objective of this study is to evaluate the feasibility of quantifying children's exposure to organophosphorus (OP) pesticides through saliva biomonitoring. By measuring OP pesticide concentrations in saliva, we intend to demonstrate that saliva biomonitoring can be used to accurately assess exposures in children.

Approach:

This project proposes saliva as an optimal medium for assessing biomarkers of pesticide exposure in children, and focuses on two OP pesticides for detailed study. In this section we first provide an overview and rationale for these choices, and then present our study design and methods. The study design for this project has three components. The first is a series of experiments in animals in that controlled oral and dermal dosing at three dose levels will be conducted for each pesticide. These studies will provide the data needed to construct pharmacokinetic models for chlorpyrifos and diazinon, and will also allow evaluation of the quantitative relationship between salivary and plasma concentrations over time. The second component focuses on improving analytical capabilities for biological specimens. We propose to modify existing ELISA methods with an extraction and clean up procedure, and to determine the accuracy and precision of the modified method. The third component of the project involves saliva and urine sampling of children in agricultural communities who have had recent exposure to the target compounds. Data collected in these studies will be used to develop pharmacokinetic models, as well as estimates of absorbed dose in children.

Expected Results:

The work outlined in this proposal represents a major step forward in the evaluation of noninvasive biological monitoring techniques for children's exposure to pesticides. This work will advance knowledge in the field of exposure assessment in several ways. First, we will be able to determine if measurement of OP pesticides in saliva is a practical method for assessing children's exposure. Saliva bio-monitoring coupled with ELISA techniques could make possible large probabilistic surveys or epidemiological studies at a fraction of current costs. The noninvasive nature of the sampling means that a series of samples could be collected to provide exposure profiles of children over extended time periods. Second, measurement of pesticide concentrations in saliva can provide a much better estimate of internal dose, thereby improving current risk assessments for children. Saliva monitoring is an ideal approach for characterizing aggregate exposures, and could also be extended to evaluate cumulative risk, i.e., multiple chemicals could be analyzed from a single saliva sample. Third, saliva sampling will result in an improved understanding of the pharmacokinctics of these chemicals in humans. Such pharmacokinetic information should improve the accuracy of risk assessments. Finally, the relative simplicity of saliva monitoring can be combined with more traditional exposure assessment methods (e.g., air, food, and housedust sampling) to better characterize pesticide exposure pathways for children.

Publications and Presentations:

Publications have been submitted on this project: View all 8 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 3 journal articles for this project

Supplemental Keywords:

toxic chemical, survey, epidemiology., RFA, Health, Scientific Discipline, Toxics, Environmental Chemistry, Health Risk Assessment, pesticides, Susceptibility/Sensitive Population/Genetic Susceptibility, Biochemistry, Environmental Monitoring, Children's Health, genetic susceptability, pesticide exposure, sensitive populations, infants, dermal contact, chlorpyrifos, exposure, survey, air pollution, children, children's vulnerablity, insecticides, toxicity, pesticide residues, exposure pathways, saliva, biological markers, dietary exposure, exposure assessment, organophosphate pesticides, Diazinon

Relevant Websites:

Synthesis Report of Research from EPA’s Science to Achieve Results (STAR) Grant Program: Feasibility of Estimating Pesticide Exposure and Dose in Children Using Biological Measurements (PDF) (42 pp, 3.87 MB)

Progress and Final Reports:

2001 Progress Report
2002 Progress Report
2003 Progress Report
Final Report