Edenton: Carcinogen level in drinking water violates state law


Anne-Marie Knighton


By Miles Layton
Chowan Herald

Friday, September 21, 2018

EDENTON — Edenton officials notified water customers this week that the town’s drinking water is in violation of state law because it contains elevated levels of a chemical linked to bladder and other forms of cancer. 

The notice to Edenton’s 2,107 water customers follows an Aug. 29 letter from the N.C. Department of Environmental Quality advising the town its drinking water contains elevated levels of trialomethanes, or THMs, a chemical by-product that forms when chlorine is used to disinfect drinking water.

“Although this is not an emergency, as our customers, you have a right to know what happened, what you should do and what we are doing to correct this situation,” Edenton Town Manager Anne-Marie Knighton said in the letter, which customers received in their September water bills.

According to Knighton, water samples collected in March from one or more the town’s sampling sites showed THM concentrations exceeding the maximum allowable under state law. The site with the highest average level of total THMs had a concentration of 0.167 milligrams per liter — twice the average standard of .080 mg/L.

In addition, water samples collected in June from one or more sites again showed THM concentrations exceeding the standard, and the site with the highest average level of total THMs with a concentration of 0.222 mg/L — nearly three times the average.

Exposure to THMs may pose an increased risk of cancer, according to the National Drinking Water Clearinghouse. THMs are linked to bladder cancer as well as to damage to the heart, lungs, kidneys, liver, and central nervous system.

Two THMs — chloroform and dibromochloromethane — are carcinogens; and another THM, bromodi-chloromethane, has been identified as a mutagen, which alters DNA. Mutagens are considered to affect the genetics of future generations in addition to being carcinogenic. 

Knighton there is no need to boil water or take other corrective actions. However, anyone with specific health concerns should consult a doctor. The letter said anyone with a severely compromised immune system, or who has an infant or is pregnant or elderly should seek advice from a health care provider.

If the THM levels had posed an emergency, customers would have been notified within 24 hours, she said.

“However, some people who drink water containing trihalomethanes in excess of maximum contaminate levels over many years — the state defines as 70 years — may experience problems with their liver, kidneys or central nervous system and may have an increased risk of getting cancer,” Knighton said.

All towns and cities are required by the state to routinely monitor for the presence of contaminates such as THM in drinking water.

Knighton said Edenton has been exceeding the total THMs maximum contaminant level since 2015, when state rules changed. The town has been notifying water customers of the violations as well as Edenton’s plan of action to bring the water system back into compliance.

“Because they have been complying with the requirements of the Administrative Order and have been performing public notification to their customers, we have not issued any penalties for the maximum contaminant level violations at this time,” said Turner Morrison, a spokesman for the compliance services branch of the Public Water Supply Section at DEQ.  

According to Knighton, Edenton is expected to continue to be in violation of the state drinking water standards until May 2019 when upgrades are completed to one of the town’s water treatment plants. 

Edenton has received final approval from the U.S. Food and Drug Administration to proceed with bidding for a $3.6 million project aimed at renovating its water system. Bids will be received in October, and after financing is approved by the state, construction will begin in January. 

“Until the necessary improvements are installed, the Town will continue to make all reasonable efforts including line flushing, reducing the level of chlorine injected into the water at water treatment plants and more to reduce to reduce the the total THM levels in the water system,” Knighton said in her letter.