Download An Integrated Approach for Source Water Protection and Awareness

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
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.
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. 2002. Revised risk assessment for atrazine.
U.S. EPA. 1998. Method 4670, Triazine herbicides as atrazine in water by
quantitative immunoassay. Washington, D.C. 18 pp.
U.S. EPA. 2007. U.S. EPA Atrazine. Web Page accessed September 10, 2007.
www. http://www.epa.gov/oppsrrd1/reregistration/atrazine.
Figure 3
Acknowledgements
Figure 3. Variation in Spa Lake atrazine concentrations (ppb) with depth (m)
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Atrazine (ppb)
Methods
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
Results
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
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Depth (m)
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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.