State health and utility officials are puzzling over detections of toxic chemicals used to make nonstick, non-stain coatings in two Artesian Water supply wells in the New Castle area, findings that prompted a full shutdown of the water sources.
One of the two perfluorinated chemicals involved was detected at up to nine times higher than a provisional level set by the EPA in 2009: perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA).
The Wilmington Manor treatment plant shutdown was the latest in a periodic and costly run of contamination problems for Artesian Water, the state’s largest residential supplier, and marked the state’s first significant finding for PFOS or PFOA in a water supply.
“I don’t think anybody knows the source at this point,” said Joseph A. DiNunzio, Artesian’s executive vice president. “You never like to see that. We’re on the hook for treatment here, entirely. Unfortunately, it becomes part of the cost of water for customers.”
The Division of Public Health’s Office of Drinking Water posted a notice of the detections in mid-June, with the disclosure standing out from more-typical problems involving high levels of nitrates or bacteria in small community systems or individual business sources.
DiNunzio said that the Wilmington Manor wells, which date to the late 1940s and mid-1950s, are a small part of the company’s large network of water sources, with its contributions quickly diluted in the system. Up to 1.8 parts per billion of PFOS were detected in the wells, well above the provisional 200 parts per trillion level set by the EPA.
The company is considering treatment options, which include installation of a carbon filter system or other alternatives, DiNunzio said. The Wilmington Manor wells draw from groundwater in the 40- to 80-foot range that was classified as “highly vulnerable” to contamination in 2003.
Perfluorinated chemicals, or PFCs, have been used since the 1950s but emerged as a national and world issue more than a decade ago when scientists recognized their persistence in the environment and in living tissues. Wide use led to detections of the compounds globally, including in wildlife found in the Arctic.
Water supply contamination traced to a DuPont Co. plant in West Virginia that supplied chemicals for Teflon-making operations eventually led to federal scrutiny, a multimillion dollar community lawsuit settlement and major industry phaseouts of some of the chemicals.
A scientific advisory panel to the Environmental Protection agency branded the compounds “likely” carcinogens, although the agency has yet to approve a risk or classification label.
Tracy Carluccio, deputy director of the Delaware Riverkeeper Network, said PFCs are a major issue for some South Jersey water utilities, most recently Paulsboro and West Deptford Township, where very high levels of a potentially more-toxic variety of PFC have been detected.
“We need to pay attention to this, because communities are demanding it. It’s still not being addressed by our federal agencies to the level of action that’s needed because of the toxicity,” Carluccio said.
She added that earlier testing in public supply wells around the DuPont Co. Chambers Works, where some types of PFCs have been used or sent to disposal, also had turned up concerns.
Investigators traced the contamination in the Paulsboro case to a Solvay Solexis Inc. plant that makes durable plastics. The Agency for Toxic Substances and Disease Registry in April agreed to investigate public exposures to the chemical after the Riverkeeper group petitioned for the study.
In Delaware, Artesian added the Wilmington Manor wells to a slowly growing list of wellfields bruised by human activities. The company has been seeking reimbursement for more than a decade for a million-dollar filter system it had to install on one of its largest well clusters, near Llangollen Road.
Two chemicals from a nearby toxic landfill long under control of the federal Superfund program are believed to have crept through the ground and into the Llangollen wells.
“That’s a very frustrating process,” DiNunzio said. “We’re kind of caught in the middle of it, and it takes, from our perspective, much too long to get the compensation that is pretty clearly due.”