Experts and concerned community members yesterday dove into the murky questions that surround water quality in Columbia, including those about contamination and treatment for which there are few answers.
At an Environment and Energy Commission meeting last night, Water and Light Director Kraig Kahler talked about the city’s response to elevated levels of a carcinogen, trihalomethanes, found at elevated levels in Columbia’s drinking water last year.
He said that after the University of Missouri conducted a series of tests and experimented with adding ammonia to water samples, THM levels dropped by 50 percent. The city is moving forward with a large-scale plan to add ammonia at the water treatment plant.
This will likely keep THM levels below the limit of 80 micrograms per liter, Kahler said, but lingering questions remain about where and why the THMs are showing up in the city’s water in higher levels.
The longer water sits in the pipes of the distribution system, the more likely it is that THMs will form. Because samples are taken at the point farthest out in the system and Columbia’s system keeps expanding to meet the city’s needs, the increased levels could be attributed to water sitting longer, Water and Light spokeswoman Connie Kacprowicz said.
Another contributing factor was that the maximum allowable levels have dropped recently, from 100 micrograms per liter to 80.
It’s known that organic material aids in the formation on THMs, and some have speculated that treated effluent water from wetlands near the McBaine bottoms could be contaminating the drinking water wells nearby.
The Environment and Energy Commission invited representatives from the U.S. Geological Survey to discuss their research on ground water flow patterns in wetlands near the city’s drinking water wells.
Data show that flow patterns have changed since the drinking water wells have been drilled, said USGS hydrologist Michael Kleeschulte, and some wetland water is flowing north toward the wells.
“It seems water is flowing in that direction, but should I be worried?” asked Commissioner Dan Goldstein, echoing the concerns of the nearly 30 gathered. “If effluent is coming into the water supply, is it a problem?”
Terry Timmons of the Missouri Department of Natural Resources said that’s the million-dollar question.
“I mean, you can treat raw wastewater to the point of being able to drink it,” he said. “Is it a concern? It’s something we need to keep an eye on.”
Reach Sara Semelka at 573-815-1717 or e-mail firstname.lastname@example.org.