Monitoring Herbicides in Midwest Drinking Water
Washington - Sampling of water running through the St. Joseph River
watershed in northeast Indiana is showing glyphosate herbicide
contamination to be minimal, according to Agricultural Research
Service (ARS) studies. Glyphosate levels exceeded the federal
limit for drinking water only once during three years of testing.
That's good news to about 200,000 residents of Fort Wayne, Ind., and
to some two dozen other small, rural communities that rely on this
watershed for their drinking water.
However, three years of testing data from the ARS National Soil Erosion
Laboratory (NSERL) at West Lafayette, Ind., show that atrazine herbicide
is often found above the U.S. Environmental Protection Agency limit
for drinking water. Drinking water treatment plants in the Fort Wayne
metropolitan area use activated charcoal to remove atrazine that has
most likely run off from cornfields. Atrazine is widely used to
control weeds on Midwestern cornfields.
Since many farmers in the St. Joseph River watershed region must rely on
drainage pipes and ditches to get their fields dry enough to plant, ARS
supports a project focused on measuring--and curbing--runoff pollution
from these drainage systems.
Runoff from farms carries nutrients and soil, as well as pesticides, to
the St. Joseph River. Scientists involved with this watershed project
are looking at a variety of drainage improvements, such as maintaining
an even water table, adding alum or gypsum to reduce contaminant levels
in runoff, and filtering standing water.
The ARS leader of this project, Chi-Hua Huang, also heads NSERL. That
facility was recently converted into the agency's newest water-quality
lab. It's the only lab involved in the U.S. Department of Agriculture's
new Conservation Effects Assessment Project (CEAP) that is sampling
water for glyphosate (Roundup), the herbicide that's increasingly
being substituted for the older atrazine.
The NSERL has two automated systems with special extraction equipment
that can simultaneously detect five different pesticides in tiny
amounts of water.
The CEAP program is designed to make sure that taxpayers are getting
their money's worth from publicly funded USDA conservation measures
administered through the Farm Security and Rural Investment Act--the
"Farm Bill."
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