City water customers can expect a notice with their bill next week regarding a slightly higher than permitted level of disinfectant by-product known as TTHM in their drinking water.
According to Utilities Superintendent Don Weingart, the water remains safe to drink and the city's taking steps to keep the levels in line with state rules.
TTHM stands for Total Trihalomethanes. The by-products are formed when naturally-occurring organics, such as decaying leaves, come into the water supply and react with the chlorine used as a disinfectant to control contaminants in the water.
He said it's more of a problem during the warmer weather periods in late summer and early fall, noting that the levels are well below the limits during three of the four quarters of the monitoring period.
The city received a notice of violation of the maximum contaminant level for TTHM from the Ohio Environmental Protection Agency dated Tuesday, saying the annual average of four samples taken from the line serving Kent State University Salem campus was 0.089 milligrams per liter or 89 parts per billion. The standard established by the state is 0.080 mg/l or 80 parts per billion. The monitoring period was from April 18, 2013 to Jan. 9, 2014.
The city was required to establish points for taking samples from lines with the longest water storage or age and can't deviate from those points. Weingart said the city has four testing points, including the KSU Salem campus on state Route 45, the Salem Community Center on North Ellsworth Avenue, the water maintenance building on West Second Street and a private home on Brookview Drive.
Samples were taken from each point on April 4, 2013, July 15, 2013, Oct. 7, 2013 and Jan. 9, 2014. The results from those four samples were then averaged, for each point, with the average sampling from KSU Salem yielding the higher than permitted level for TTHM.
"It's a concern, but the limit has never been proven to affect the health of humans," Weingart said.
The notice outlined required actions for the city to take, including notifying customers within 30 days and consulting with the OEPA to discuss options for coming into compliance.
The notice said "the levels detected do not pose an immediate risk to your health. However, some people who drink water containing trihalomethanes in excess of the MCL over many years may experience problems with their liver, kidneys, or central nervous systems and may have an increased risk of getting cancer."
Weingart noted that the violation was not a huge amount above the limit of 0.080 mg/l, which he said is an arbitrary number. He also said again that most of the year, the levels of TTHM are well below the limit.
The city Utilities Department staff and city Utilities Commission have been discussing ways to reduce the TTHM formations besides finding ways to make adjustments during treatment at the water plant. Water age also plays a part.
The commission agreed in October to have Burgess & Niple design plans to improve the flow and circulation of potable water into the Stewart Road Reservoir, with part of the plan to have all the drinking water flow through that facility. Weingart explained that by pushing all the water through that reservoir, there will be more turnaround in the water and the water age will be reduced.
If that doesn't cause improvement, he said the commission may have to consider installing a mechanical mixer in the system at the Stewart Road site.
The commission also agreed to the purchase of Parker THM Analyzer for an estimated cost of $32,500 plus an additional $3,000 for chemicals and miscellaneous items required for operation. The machine will allow for the testing of treated water for the disinfectant by-products so adjustments can be made chemically. The analyzer can also help determine the age of the water. If necessary, older water could be flushed out of the system.
Weingart said all water systems are in the same boat, dealing with these limits which took affect last year, and they're all working to stay below the limits.