TTHM found in Victoria water

Published 11:05 am Thursday, October 29, 2015

Victoria’s water treatment plant received a “notice of violation” from the state’s health department in September because of excess levels of trihalomethanes chemical compounds.

The compounds were discovered during testing in August, a state health department official said.

The town distributed a notice about the violation to customers with their water bills on Oct. 1, said James Reynolds, deputy field director in the Virginia Department of Health’s office of drinking water’s Danville field office.

“This is not an immediate health risk,” he said. “If it had been, immediate notification to town customers would be required.”

He noted, however, that some people who drink water containing TTHM in excess of the maximum concentration levels of contamination “over many years” could have an increased risk of cancer, and may experience problems with their liver, kidneys or central nervous system.

Trihalomethanes — known as TTHMs — along with other disinfection byproducts, are formed when trace amounts of naturally occurring organic compounds in the untreated water combine with chlorine used to disinfect treated water.

The town monitors for the presence of TTHMs on a quarterly basis, and the level discovered was only slightly above acceptable levels.

Compliance with the standard for TTHM is 0.080 milligrams per liter based on the annual average for four calendar quarters, Reynolds said. Victoria’s average concentration was 0.084 milligrams per liter, he said.

Otherwise, the health department’s most recent inspection of the town’s water treatment plant was Feb. 4, and there were no major issues noted and the plant “was observed to be operating satisfactorily,” Reynolds said.

All locations within the distribution system do not have the same levels of TTHMs, Reynolds said. The levels present in the system depend on such factors as demand, how long a household’s water is in the system, levels of chlorine present, and temperature of the water, he said.

Water held longer in the distribution system can result in higher levels in the water supply, and samples collected during the summer months typically exhibit the highest levels, he said.

A notice of violation is required whenever a water system is found out of compliance with a portion of the Virginia Waterworks Regulations, Reynolds said. The notice triggers a requirement that the town notify the public about the violation “in a timely manner,” he said.

“In addition,” he said, “(Victoria) is currently conducting an evaluation of their water system from the source, treatment plant, and distribution system to determine potential causes of the exceedance and potential ways to mitigate an exceedance in the future.”

Several other localities in the area covered by the Danville field office also had excessive TTHM levels and are evaluating their water system much as Victoria is – some because of rule changes, Reynolds said.

The town also continues its quarterly sampling for TTHMs, and the monitoring will decide if further action is required.

Victoria faces no financial punishment.

The town will include potential ways to avoid a reoccurrence in an assessment of the water system scheduled to be submitted to the health department by Dec. 1.

“Based on evaluations conducted by other localities this may include operational changes such as increased flushing of water in the distribution system to reduce the age of the water in the system or optimization of chlorine dosing at the water treatment plant,” Reynolds said. “If the issue persists, additional treatment may need to be evaluated such as aeration of water system storage tanks, pre-treatment of the raw source water with an alternative oxidant, or addition of activated carbon to remove TTHMs from the water.”