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KGS Maps Show Few Areas of Mercury or Selenium Contamination in Groundwater

CONTACT: Mike Lynch, Kentucky Geological Survey, (859) 257-5500 ext. 128

Using thousands of groundwater samples collected throughout the state, the Kentucky Geological Survey has published two Information Circulars that include data summaries and maps showing the occurrence of mercury and selenium in Kentucky's groundwater. Both of these naturally-occurring metals are used in a variety of industrial products and processes, and can cause serious health effects for people exposed to them in high amounts.

But the two new KGS publications indicate that neither metal has been found in high concentrations at more than a few locations. In fact, about 99% of the sample sites plotted on the two maps showed levels at or below the federal “maximum contaminant level” (MCL) considered safe for drinking water.

These publications were made possible by a 1990 state law establishing the Kentucky Groundwater Data Repository (maintained by the KGS) to archive and disseminate groundwater quality data collected by various state agencies. Data from the repository were compiled into the new KGS publications, Groundwater Quality in Kentucky: Mercury and Groundwater Quality in Kentucky: Selenium . These reports are part of ongoing work by the Kentucky Interagency Groundwater Monitoring Network, which was established by legislation in 1998. They provide useful information for individuals or agencies with an interest in regional groundwater quality.

Over 3,500 water samples in the Repository from 872 Kentucky wells and springs had been tested for mercury; over 4,600 samples from 785 sites had been tested for selenium.

“It's important for us to know what's in groundwater in Kentucky” says the KGS's Steve Fisher, one of the authors of the publications. “About a quarter of the state's population relies entirely or partially on wells or springs for their drinking water.”

There were only 6 sites across Kentucky where mercury levels were found above the MCL, and 20 sites where selenium levels exceeded the MCL. The above-MCL sites were spread across the state with no apparent concentration in particular areas or geologic settings.

“These two publications provide a concise summary of the state's overall situation regarding mercury and selenium in groundwater,” says Bart Davidson of the KGS, another author of the reports. “And while the situation does look positive for the state based on existing information , we urge anyone who plans to begin using a well or spring for human consumption to have it tested for potential contaminants.”

Summarizing groundwater-quality information is an ongoing KGS activity. Previously published maps show levels of nitrate, fluoride, pH, and arsenic in groundwater; KGS is currently working on more reports including metals, herbicides and pesticides in groundwater.

Paper copies of the new publications are available for $1.50 each from the KGS Public Information Center on the UK campus at (859) 257-3896 or toll-free at (877) 778-7827. They can also be downloaded in “.pdf” format at the Survey's web site: http://kgsweb.uky.edu/main.asp