The U.S. Environmental Protection Agency (EPA), Region 9, has ordered the City of Avenal, California, to develop a treatment plan to reduce levels of disinfection byproducts from drinking water treated by the city's water system and notify the public that these chemicals has been detected at concentrations above the drinking water standard.
The EPA promulgated new disinfection byproduct regulations in December 1998 to protect public health from potentially harmful byproduct chemicals formed when chlorine reacts with natural organic compounds during the treatment process. This is the second action taken by the EPA in California under the agency's new regulation.
"Chemical byproducts in treated drinking water need to be monitored, reported and reduced to meet federal health standards," said Catherine Kuhlman, EPA's water division director for the Pacific Southwest region. "Public drinking water systems have a responsibility to notify the public of what chemicals have been detected in their drinking water and then take action to remove them."
The byproduct chemicals detected in the City of Avenal's water system are total trihalomethanes, which after many years of consumption may cause some people to experience liver, kidney or central nervous system problems and may increase the risk of cancer. Although detected in trace amounts over the federal drinking water standard, the district is required to monitor and notify the public when detection goes above health-based standards. The drinking water standard for total trihalomethanes is 80 parts-per-billion, Avenal's system had a range from 96 to 98 parts-per-billion. While the system exceeds the standard, no effects on human health are anticipated from this short-term exposure.
The city was required to monitor its water system for these chemicasl on a quarterly basis beginning January 2002. The city violated the standard from January 1, 2002 to March 31, 2003.
The order requires the city to hire an engineer to develop a master plan and treatment methods to reduce disinfection byproducts to below federal standards. The city also must notify its customers of its violations of health standards and failures to submit a monitoring plan to the state as well as perform required sampling.