1. An Integrated Approach for Source Water Protection and Awareness in
Rural Agricultural Watersheds
Ritchie D. Taylor, Vijay Golla, Joey Willcox, Jerrod Nelms and Shaden Melky
Western Kentucky University, College of Health and Human Services, Department of Public Health, Environmental Health Science Program
Figure 1
Figure 2. Spa Lake Watershed GIS Land Use Analysis
Abstract
Results
Atrazine, a triazine herbicide and chemically an organochlorine, is used worldwide for controlling broad leaf weeds in corn, sorghum, and wheat. Atrazine is regulated by the Safe Drinking Water Act (SDWA) through the United States Environmental Protection Agency (U.S. EPA) and has a Maximum Contaminant Level (MCL) of 3.0 parts per billion (ppb). Atrazine has been found to contaminant public water supplies in agricultural watersheds and is under special review by the U.S. EPA. Transport of atrazine to streams, rivers, groundwater, and reservoirs occurs primarily by nonpoint source runoff from fields. However, inadequate disposal and atmospheric deposition can increase transport to water supplies. During the period from 1999, studies have been ongoing in rural watersheds in western Kentucky to quantify both the distribution and occurrence of atrazine. Beginning in 2001, farmers in two rural watersheds agreed to reduce the usage of atrazine and work with stakeholders to assess how use reductions would affect the distribution and occurrence. The goals of this study were realized as we used the assessment of the environmental occurrence and distribution of atrazine as a tool for public health protection and source water awareness in agricultural watersheds. Results of the study were incorporated in a statewide education campaign for corn producers and professional pesticide applicators conducted through the Kentucky Pesticide Workgroup.
Lewisburg finished drinking water continued to exhibited atrazine levels over the MCL despite limited application seasons and educational efforts
A drought in 2001 resulted in atrazine concentrations below the MCL in the Lewisburg water system. However, reservoir samples showed elevated atrazine levels (Figure 3).
Atrazine concentrations were stratified in Spa Lake (Figure 3)
A cost share program for alternative herbicides in the Marion, KY source watershed significantly altered application of atrazine
Levels of atrazine in the Marion, KY community water supply were below the MCL after 2001.
Eight pesticide workshops were conducted throughout western Kentucky
Conclusions
A critical step within each agricultural community was to identify a stakeholder that could serve as the gatekeeper for information transfer
Educational campaigns or Best Management Practices (BMPs) alone may not be sufficient to alter herbicide use in target rural watersheds. A combination of incentives, education, BMPs, and stakeholder involvement are needed.
Use of alternative herbicides can reduce atrazine levels in rural drinking water supplies. However, alternative pesticide monitoring is needed to quantify levels in drinking water.
Future research is being conducted to quantify atrazine levels in target watersheds following pesticide use/application education
As a result of this research, a comparison of atrazine levels at the tap in farm family homes on well water vs. community water supply has been initiated
Future research is needed to quantify ecosystem level impacts and integrate results into feedback for BMP
Introduction
A program was initiated in 1999 to monitor target rural water systems in western Kentucky for elevated levels of herbicides. Specifically, it was found that atrazine concentrations were above the Maximum Contaminant Level (MCL) for atrazine in two small community drinking water systems. The watersheds providing source water to these systems were 3,200 and 11,000 acres, respectively. Initially monitoring was conducted only on the source water entering the facilities and the finished treated drinking water (Figure 1). The largely agricultural watersheds were dominated by cropland, pasture, and deciduous forest, as shown in Figure 2. Each watershed drained to an impoundment which received stormwater runoff with significant atrazine concentrations, as determined by surface water sampling. According to EPA’s Revised Risk Assessment (2002), twenty-nine community water systems in the U.S. had intermediate to chronic term exposures of atrazine and its metabolites that exceeded levels of concern for infants. Lewisburg and Murray, Kentucky, were identified as two of those community water systems of concern. The objective of this study was to utilize the assessment of the environmental occurrence and distribution of atrazine as a tool for public health protection and source water protection in agricultural watersheds. Results of the study were incorporated into a statewide education campaign for con producers and professional pesticide applicators, conducted by the Kentucky Pesticide Workgroup.
References
U.S. EPA Revised risk assessment for atrazine.
U.S. EPA Method 4670, Triazine herbicides as atrazine in water by quantitative immunoassay. Washington, D.C. 18 pp.
U.S. EPA U.S. EPA Atrazine. Web Page accessed September 10, www.
Acknowledgements
Thanks to Ernest Collins with the Kentucky Department of Agriculture for his work on agricultural education and insights into this project. A special thanks to both the Lewisburg and Marion community water system employees for assistance with water sampling. We are grateful to corn producers in western Kentucky for their willingness to participate in this research and look for ways to reduce herbicide runoff. Lastly, we would like to thank Western Kentucky University for support to conduct this research. Funding for the project was provided by the Kentucky Dept. of Agriculture, U.S. EPA, Western Kentucky University, and the Kentucky Department of Conservation.
Methods
Figure 3
Study location - Lewisburg, KY, Marion, KY, and western Kentucky counties
Collected water samples for atrazine immunoassay analysis (EPA 1998)
Weekly sampling of water treatment plant raw and finished water
Monthly sampling of reservoirs
Monthly sampling of surface water tributaries
Monthly sampling of stratified water column in Spa Lake, Lewisburg, KY
GIS Land Use Analysis of target watersheds
Stakeholder meetings in target watersheds
Cost share program in Marion, KY
Incorporated results into statewide educational campaign – eight workshops across western Kentucky