A report from the City of Bloomington's Utilities Water Quality Office shows that organic contaminants in Bloomington's drinking water have been increasing over the past several years.
The organic contaminants of concern are haloacetic acids (HAA5) and total trihalomethanes (TTHM). Both are by-products of the water treatment process.
The Environmental Protection Agency monitors these levels nationally. Although the average in Bloomington's water is below the EPA's allowable level, the highest detected levels of both HAA5 and TTHM in 2014 were above the allowable level.
According to the report, prolonged exposure to excess levels of HAA5 may increase risk of cancer. Prolonged exposure to excess levels of TTHM may cause liver and central nervous system problems, as well as an increased risk of cancer.
Patrick Murphy, Director of Utilities for the City of Bloomington, says he is confident in the safety of Bloomington's drinking water but the increasing levels of HAA5 and TTHM are concerning.
"By far, this is the biggest, I think, challenge that the utility is facing right now," he says. "It transcends conservation and everything else."
The Utilities Department is taking steps to address the issue. Murphy says water age, which is the amount of time water sits stagnant in the system, can increase the levels of these contaminants. One way to reduce the levels is to flush fire hydrants more often.
"We're a very conservation-oriented utility, but this is one of the ways to undertake and manage water aging," Murphy says.
The department also plans to conduct an optimization study to evaluate the city's water purification process and determine whether any changes need to be made.
"I think this is a number one concern, and we need to bring our resources to bear on it," Murphy says. "And that's something that we'll have to look at in the next year when we talk about revenue increases and utility rate increases."