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Protection of Well-Water Supplies from Nitrate Contamination

Contact: Glynn Beck

Groundwater is used by more than 75 percent of the residents in the Jackson Purchase Region. Approximately 60 public water utilities provide water from wells or well fields to residents, businesses, schools, and industry.

A greater proportion of private wells in the Jackson Purchase yield water with nitrate over the U.S. Environmental Protection Agency's maximum contaminant level (MCL) for nitrate than in other parts of Kentucky. Data collected as part of the Ground Water Education and Testing Program in the early 1990's show that 5.5 percent of wells in the Jackson Purchase exceed the MCL and 13.7 percent exceed half of the MCL.

During the past year the Kentucky Geological Survey conducted research to better delineate the sources of elevated nitrate in the Jackson Purchase. Forty-three domestic water wells were sampled in Hickman County for nitrate-nitrogen. Of those wells, 12 percent exceed the MCL for nitrate and 37 percent exceed half of the MCL.

To determine the possible sources of these elevated nitrate concentrations, detailed land-use and well-construction surveys were completed, bromide tracer tests were performed on domestic wells to determine their integrity, and caffeine, nitrogen, and oxygen isotope samples were collected. Research indicates that the possible sources of nitrate are chemical fertilizers, leaky septic tanks, and active and abandoned animal feedlots, in possible combination with poor (leaky) well construction.

The findings of this research will be relayed to the public through State and local officials and outreach education programs for citizens.

Funding for this project is provided by Kentucky Senate Bill SB-271, which is administered through the University of Kentucky College of Agriculture. It is a cooperative effort between the Kentucky Geological Survey, the UK Department of Agronomy, and the UK Department of Biosystems and Agricultural Engineering