“In early spring, Lake Michie stirs to life, with fishers and the Duke University women’s rowing team taking to the water at dawn. The 480-acre reservoir near Bahama is not only a source of largemouth bass, but it is also a boating destination, and it provides Durham with 30 million to 35 million gallons of drinking water each day.
Testing by the City of Durham’s water department detected low levels of perfluorinated compounds in both Lake Michie and the Little River, another drinking water source, near Treyburn. The levels ranged from 2.4 parts per trillion to 7 ppt.
Treated water from the Brown plant, which flows from the thousands of taps in Durham, also had low concentrations of the compounds — PFOA, PFOS and PFB — ranging from 2.7 ppt to 4.8 ppt. (The Williams plant is offline until later this year for renovations.)
Vicki Westbrook, assistant director of water management, announced the findings last night at a GenX forum sponsored by the Sierra Club and NC Central University School of Law. The city had just received the results within the previous 24 hours.
These are not the same compounds as GenX, which has been found in public drinking water systems in New Hanover and Brunswick counties, and private wells in Bladen, Cumberland and Robeson counties. But PFOA, PFOS and PFBs are cousins to GenX; at high levels, exposure has been linked to cancer, hormone disruption, liver and immune system damage, and thyroid changes. Still, there is little scientific data on the health effects and safe levels of perfluorinated compounds.
The EPA has established a health advisory goal of 70 parts per trillion a combination of PFOS and PFAS, but there is no enforceable regulatory standard for them under the Clean Water Act or the Safe Drinking Water Act. Some states, though, have established their own legal limits for PFOAs. Vermont has set its threshold at 20 ppt for PFOA , while New Jersey has proposed limits of 14 ppt, according to the Environmental Working Group.
Westbrook said the source of the contamination is unknown. The city has surveyed all of its industrial users, she said, and none reported the use of these compounds. Nor do Lake Michie or Little River receive industrial or wastewater discharges. No biosolids or sludge are currently being applied in northern Durham and southern Person counties, she said. That leaves air emissions and atmospheric deposition as the culprits. The compounds can leave the stacks at an industrial facility, travel on the wind and fall to the ground or into water.
Of the three compounds found in Durham’s water supply, only PFB is still commercially produced. It is used in flame retardants, metal plating, pesticides and water-repellant coatings.”
Read the full article by Lisa Sorg.