Delaware’s Division of Public Health (DPH) and Department of Natural Resources and Environmental Control (DNREC) announced this week that they have increased monitoring of water samples at the Sussex County Industrial Airpark.
The monitoring is being undertaken in response to recent findings of groundwater contamination and to prevent levels of perchloroethylene from exceeding Delaware’s regulatory standard by early detection and response.
There is no immediate risk to anyone who drank the airpark’s water, officials said.
DNREC is attempting to identify the source and extent of the contamination. Sussex County installed a granular activated carbon treatment system Sept. 16 to remove the contaminant. DPH was to perform additional drinking water tests this week.
Perchloroethylene, or PCE, is used primarily for dry cleaning and to degrease metal. The maximum contaminant level for PCE in drinking water is an average of 5 parts per billion (ppb) over the most recent four quarters. This typically means that a single test result does not put a water system in violation of the regulatory standard. Test results are as follows: Oct. 30, 2007, 1.18 ppb; Feb. 12, 2008, 0.80 ppb; April 24, 2008, 3.74 ppb; July 24, 2008, 6.52 ppb.
While the airpark’s current four-quarter average is 3.06 ppb, DPH and DNREC and Sussex County are working to correct PCE levels before they violate the state standard.
DNREC has initiated soil and groundwater investigations within the airpark in an attempt to locate a source and extent of the contamination. The results of DNREC’s initial groundwater sampling down to 60 feet deep have not detected PCE in groundwater.
DNREC is working with Sussex County to investigate and identify chemicals that have been used by the airpark’s tenants, in order to locate the source of the contamination. Once located, DNREC will pursue the responsible party to undertake or reimburse the State for cleanup efforts. The state Hazardous Substance Cleanup Act Fund will be used, if necessary, for additional investigatory and cleanup efforts.
The Sussex County engineer advised airpark businesses of the chemical levels by hand-delivering a letter Sept. 12. Businesses in the airpark were informed about the chemical in the central water system and about the plan to install the carbon treatment system.
The Sussex County Airport, which is adjacent to the airpark, is served by a completely separate water system.
Over many years, some people who routinely drink water containing PCE levels in excess of 5 ppb could experience liver problems and may have an increased risk for cancer. Drinking large amounts of PCE may also affect the central nervous system.