The U.S. Environmental Protection Agency (EPA) recently issued an order to Doña Ana County, N.M., and the City of Las Cruces, N.M., to clean a contaminated ground water aquifer under the city. The aquifer has been used by the City of Las Cruces for drinking water, and poses an imminent and substantial danger to anyone who drinks from it.

The city and county will be required to build a system that will extract, treat and remove the contaminant from the aquifer. The contaminant, perchloroethylene (PCE) – widely used for dry cleaning and degreasing, is above the maximum contaminant level under the Safe Drinking Water Act. Doña Ana County is located in south-central New Mexico, and bordered by Mexico and Texas to the south.

In October 2009, EPA also ordered the county and city to develop a plan for the removal of the contamination. The current order directs the county and city to complete the remedial action according to the 2009 plan.

The source of the contamination has been identified as historical releases that occurred at the site known as the Griggs and Walnut Ground Water Plume Superfund Site, named after two intersecting streets in Las Cruces. The releases most likely were associated with maintenance activities or waste disposal.

On June 14, 2001, EPA listed the site on the National Priority List, EPA’s list of uncontrolled hazardous substance releases in the United States that are priorities for long-term evaluation and response.

PCE in humans has been known to cause adverse neurological, liver and kidney effects following short-term and long-term inhalation exposure. Some people who drink water containing PCE in excess of the maximum contaminant level over many years could have problems with their liver, and may have an increased risk of getting cancer.