COLUMBIA — Out of 3,000 Missouri public water supply systems, Columbia’s is one of 12 to violate Environmental Protection Agency standards for a contaminant in drinking water that’s a byproduct of the disinfection process. The violation is the first time Columbia’s water supply has failed to meet EPA standards in the past 30 years.
Despite surpassing the federally mandated levels, officials said there is no immediate health risk posed by Columbia drinking water.
The elevated contaminants are trihalomethanes, or THMs, which are chemicals that form from chlorine and organic materials. Chlorine is put into the water supply to prevent the spread of water-borne illnesses.
The level of THMs in Columbia’s water supply has been steadily increasing over the past four years, according to Columbia Water and Light.
THM levels can increase when water sits in distribution lines, which is more likely to occur in colder months because people use less water. Warmer weather increases water usage and flow through the city’s system.
Floyd Turner, manager of water operations for the city, confirmed that THM levels rose to 82.3 parts per billion in 2007, above the permissible level of 80 parts per billion. Columbia Water and Light notified the Missouri Department of Natural Resources of the increase in THMs in Columbia’s drinking water in November.
The Department of Natural Resources recently publicly confirmed that Columbia had been in violation of standards set by the EPA, but that THM levels are now below the federal clean water standard.
Columbia’s water is tested more than 4,000 times per year in 39 locations, according to a press release from Columbia Water and Light. Last year’s THM concentration was computed from averaging four tests throughout the year.
Columbia Water and Light lowered the level of THMs by reducing the amount of chlorine going into the water supply. This helped reduce the amount of THMs produced by reactions with organic matter. By February, they were back under the maximum permissible limit. The last measurement, taken in February, was 77 parts per billion.
Missouri’s Water Resources Research Center will be conducting tests to find a solution to the high level of THMs in drinking water. On Monday, the City Council will discuss approving $91,000 of funding for this research.
Water and Light officials were quick to note that drinking Columbia’s water poses no risk at this time. As long as levels are below 80 parts per billion, the water is safe; however, THMs can be a health risk after long-term exposure if levels are elevated.
According to the Missouri Department of Natural Resources, drinking two liters, equal to about half a gallon, of water every day for 70 years will lead to three or four cancers per 10,000 people at the permissible level. If THM levels exceed EPA standards, damage to the liver, kidneys and central nervous system may occur.
Although this violation occurred in Columbia, Terry Timmons, environmental manager at the state Department of Natural Resources, said most violations occur in smaller communities in northern Missouri. Timmons said smaller communities are more vulnerable because they treat surface water differently than larger cities.
Boonville, for example, has had problems with elevated THM levels in the past, but the city is currently in compliance with EPA standards.
Although regulations have become more stringent and smaller communities work harder to regulate contaminant levels, Timmons said he wouldn’t classify elevated THM levels as a concern statewide.
“I wouldn’t paint it as a big problem,” Timmons said. “The goal is to have everyone meet the standards. I’m sure Columbia will get it under control.”