PESTICIDE EXPOSURE AND POTENTIAL HEALTH EFFECTS IN YOUNG CHILDREN ALONG THE U.S.-MEXICO BORDER
Impact/Purpose:
The overall purpose of the Pesticides in Young Children - Border States program is to describe the relationship of health outcomes in children along the United States and Mexico border to repeated pesticide exposures via multiple sources and pathways. The current effort will analyze the data available from Phase I and II studies to identify and address critical questions about three major areas: (1) the applicability of pesticide biomarkers for use as markers of exposure, (2) the predictive capability of quesionnaires for estimating exposure, and (3) identification of the most appropriate cohorts to be included in the Phase IIIb studies.
Description:
The pesticides in young children border states program includes a series of studies designed to develop and implement an approach to examine the cumulative risks and potential health effects in children from repeated exposure to pesticides via multiple sources and pathways. Research is being conducted in the U.S.-Mexico Border States of Arizona, California, New Mexico, and Texas as part of the Environmental Health Workgroup on the U.S.-Mexico Border program developed with the passage of the North American Free Trade Agreement (NAFTA). A three phase approach was undertaken to address the project objectives. Phase I was a planning phase and included a review of existing environmental pesticide exposure & health data and identification/review of techniques to measure exposure biomarkers in biological fluids. Geographic Information System (GIS) maps were produced for the border area to delineate the location of agricultural fields, schools, parks, homes, health clinics, and the temporal application of pesticides. In addition, a workshop on health effects assessment related to pesticides in young children was held to recommend health endpoints to be used in the survey. Phase II evaluated the extent and distribution of pesticide exposure in children living in the border region and the identification of children with the highest levels of exposure. The initial Phase II studies have been completed. Current efforts focus on data analysis and reporting. It is likely that additional Phase II studies will be necessary, since the initial analyses suggest that the exisiting Phase II studies have not provided a definitive population for the Phase III activities. Phase IIIa will include a more complete monitoring of children classified as "high end exposures" in Phase II. Follow-up on these children will include detailed measurements of their environmental exposure and biological monitoring for levels of metabolites. From this first part of the Phase III effort, a study will be designed to evaluate the relationships between pesticide exposures and selected health outcomes and to define specific hypotheses to be tested. An epidemiological study (Phase IIIb) may then be performed to examine the specific hypotheses about the impact of pesticide exposure on health status/outcome of children.
Record Details:
Record Type:PROJECT
Start Date:10/01/1998
Completion Date:09/01/2004
Record ID:
29208
Keywords:
HUMAN EXPOSURE, PESTICIDES, CHILDREN, ENVIRONMENTAL JUSTICE,
Project Information:
Progress
:Phase I (completed). An inventory of crops and pesticide usage was compiled for the four border states and is available for distribution. Excellent data were available for California and Arizona, while the data for New Mexico and Texas could only be estimated since these states do not require the reporting of pesticide sales and usage. A limited effort was also made to survey health data bases and resources in Texas and New Mexico. An extensive and coordinated effort was made in each of the four states to create maps of crops, pesticide usage and population distributions using the Geographic Information System (GIS). A GIS database has been created to assist in planning subsequent health effects studies in the border region. The GIS maps can help identify areas of high pesticide usage that overlap with populations of children, including schools. A review of available pesticide analysis methods was also compiled for use in planning future studies. The Texas Border Health Survey, a survey of health and environmental conditions in Texas border counties and colonias, was conducted at a household level to describe the current demographic characteristics, connections to Mexico, health risks and health conditions, child health and well-being, living conditions and neighborhood problems. This study identified several areas for further investigation including exposure to certain environmental contaminants, microbiological contamination of drinking water storage containers, and use of well water.
In December 1997 a workshop was held in El Paso, TX to review available health endpoints for use in studies of young children. Five disciplines were included: neurobehavioral, developmental, pulmonary, immunological and cancer. Discussion groups were formed on the first day to recommend specific health endpoints and on the second day to draft study designs in each of the disciplines. Study designs originating from this workshop were expanded into several Phase II studies. Keynote addresses and recommendations of workgroups are published as an EPA document.
Phase II. The main questions addressed in Phase II where the extent and distribution of pesticide exposure in children living in the border region and the identification of children with the highest levels of exposure. The studies below have been completed and data analysis is underway. However, these studies have revealed additional data gaps that must be filled before Phase III can be succesfully undertaken. A workshop was held and two studies are being planned. The first will be a study of the excretion, over time, of urinary biomarkers of pesticides. This data is needed to determine the timing and number of urine samples that are needed to describe a pesticide exposure event. This is critica because of the short biological lives of modern pesticides. The second study will compare the pesticide exposures of children in different residential environments, such as agricultural, suburban, and inner city. This is needed because the current studies, which have focused primarily on children in proximity to agriculture, have not identified a population of highly exposed children for the Phase III studies.
Building on information gathered in Phase I, screening studies have been conducted in three border states-Arizona, California and Texas. The Yuma study examined the hypothesis that pesticide levels in young children vary with the distance children live from agricultural fields. Urine samples were collected and analyzed using an alkyl phosphate metabolite screen to detect exposure to organophosphorus (OP) pesticides. Analyses for individual pesticides may be done later if necessary. Analysis of the data is underway.
Two Imperial Valley, CA studies, which were products of the El Paso health effects workshop in Phase I, have been conducted (field portion completed, data analysis underway).
Relevance
:The study of children's exposure and potential risk is a high priority for the Agency and the Nation. Because of macro and microlevel activities children are potentially a highly exposed population, especially to pesticides. This population, lower socioeconomic and live in agricultural areas, may have even greater potential for exposure. These studies will help investigate that premise and help provide estimates of any such exposure. Such estimates will help in environmental justice issues. This work directly supports research in Goal 8.2.1 Human Exposure Research.
Clients
:Hal Zenick, NHEERL, OPPTS/EPA, Border States
Project IDs:
ID Code
:3913
Project type
:OMIS