Levels of trihalomethanes in Columbia’s drinking water in May again violated the Environmental Protection Agency’s standards. The result from the city’s latest sample found trihalomethanes at 101 parts per billion, said Barry Kirchhoff, superintendent of the Columbia Water Treatment Plant.
Trihalomethanes are compounds that form when chlorine, which is added to drinking water to kill potentially harmful bacteria, interacts with organic matter in the water. Trihalomethanes have been linked with increased risk of cancer.
The latest results are the highest level of trihalomethanes found in the city’s drinking water in the past 10 years, according to documents provided by the city’s Department of Water and Light.
Based on May’s test results, Kirchhoff said he expects the city to receive another notice that it has exceeded the EPA’s limit of 80 parts per billion.
Columbia’s rising trihalomethane levels have sent the city scrambling for short-term remedies and long-term solutions.
The city has decreased the amount of chlorine it adds to the water in hopes of decreasing trihalomethane levels, Kirchhoff said. It has also begun flushing water out of city water mains, which drain water that has been standing in pipes. Water standing in pipes at high summer temperatures is believed to be particularly susceptible to trihalomethane formation, Kirchhoff said.
In May, the city of Columbia entered a $91,000 contract with MU to conduct tests of the city’s water system.
The university team, lead by Enos Inniss, assistant professor in the MU College of Engineering, will sample water throughout the city’s water distribution system to determine where trihalomethanes are forming. Sampling of water in the city’s 15 wells has begun, Inniss said.
Columbia’s water is tested four times a year for trihalomethanes. Compliance tests of the city’s trihalomethanes levels occur near the end of the city’s water lines, as water that travels farther in the system leaves more time for trihalomethanes to form. According to EPA standards, the average of any four tests must be below 80 parts per billion. Columbia’s November 2007 sample pushed the year’s average above this level, and the public was notified of the violation in May.
2007 was not the first time the city’s drinking water had exceeded 80 parts per billion. In 2001, trihalomethanes averaged 80.8 parts per billion, double 2000’s level of 39.43. At that time, the EPA threshold was 100 parts per billion; the standard was lowered to 80 parts per billion in 2004.
In November, Columbia voters may be asked to consider a $38.9 million bond issue, half of which would fund changes to the city’s water system that would increase water flow throughout the system and possibly slow the formation of trihalomethanes. Closing loops in the water system would decrease trihalomethane formation by making water flow continuously instead of sitting in the parts of the system, Water and Light spokeswoman Connie Kacprowicz said.
The city’s notice to its water customers in May stated that, according to the Missouri Department of Natural Resources, consuming two liters of water at the EPA’s maximum contaminant level for trihalomethanes for 70 years could result in three to four cancers per 10,000 people. Trihalomethanes have been linked to other health effects, especially for sensitive populations.
“Even when a contaminant is at the EPA level, we have to worry about more sensitive populations such as children, diabetics and the elderly,” said Olga Naidenko, senior scientist at the Environmental Working Group in Washington, D.C., a nonprofit group that advocates for reform and disseminates information on public health and the environment.
Epidemiological studies published in “The American Journal of Epidemiology” and “Epidemiology” found that trihalomethane levels as low as 50 parts per billion could be linked to bladder cancer in adults, and levels as low as 40 parts per billion can be linked with neural tube defects, small head circumference and small body length in newborns. “These are inherently dangerous chemicals,” Naidenko said.
Decreasing your ingestion of trihalomethanes is easy. Former Columbia Water Plant Superintendent John Betz recommends leaving drinking water in an open pitcher for three to four hours. Because certain trihalomethanes are volatile, they will leave the water. Naidenko suggests that houseplants will benefit from the same courtesy.
Although bottled water may seem like an appealing solution, its purity is less regulated than that of Columbia’s tap water. Carbon filtration systems are another way to decrease trihalomethane levels in drinking water, Naidenko said.
Meanwhile, the city awaits the university’s test results, which Kirchhoff says will offer a clearer view of where and why trihalomethane levels continue to rise dramatically in Columbia’s drinking water.