Council gets update on TTHM excess

Aeration systems will be installed to keep problem from reoccurring, official says

TROY, N.Y. » City officials received an explanation as to why part of the Troy water system had an excess level of a certain chemical.

While there was no danger to public health, earlier this month, a public notice was sent out to residents saying that according to quarterly water sampling results, there was too much trihalomethane (TTHM) in the drinking water in certain parts of the city. The state allows up to 80 parts per billion. One sampling location had an average of 81.6 parts per billion.

TTHM forms when chlorine, which the city’s water is treated with, interacts with naturally occurring organic compounds. There are studies suggesting that long-term exposure, several decades worth, may lead to an increased risk in certain health effects.

Chris Wheland, Department of Public Unities superintendent, said TTHM occurs in all water treated with chlorine.

“When you treat with chlorine, it reacts with organics in the water and produces trihalomethane,” he said.

He said the city monitors the chemical on a “rotational annual average.” A number of sites are regularly sampled and their running average is taken. The sites selected for testing are the ones found to typically have the highest concentrations of trihalomethane.

Wheland said he believes the increase was related to an unexpected complication stemming from a maintenance project. The department was removing two failing 3,000 gallon storage tanks at one of its facilities. Doing so re- quired the removal of part of a retaining wall.

“We took the retaining wall down, took the tanks out, the rest of the retaining wall was crumbling, so at that point we had to take the rest of the retaining wall down, rebuild the entire thing, and put the new tanks in,” Wheland said. “What was supposed to be a four or five day turnover turned into five weeks. In that time was the sampling from not only Troy, but Rensselaer, East

Greenbush, and everybody else.”

Another time there was

a high reading for TTHM came in August. He said the weather was largely dry with a few high-rain events. He believes people had been using a lot of fertilizer for their lawns and gardens and much of

it washed into the waterway. This, he said, would lead to an increase in organics, and ultimately more TTHM.

He said this is the first time there’s been an excess of TTHM in the city water system. Numerous external environmental factors can lead to a water system having an excess of a certain chemical.

To keep this from happening again, he said the plan is to install aeration systems on certain water storage tanks. This can be done in tandem with an established repainting schedule. He plans to get bids within the next few weeks and have the project going by the end of the year.

City Council President Carmella Mantello suggested that the water department use the same electronic alert system used to warn people of other emergencies.