City explains water notice

By LOU ANTONELLI

Managing Editor

Clarksville water customers will get a formal notice in the mail next week about the city’s water containing a contaminant that triggers a reporting advisory.

The notice is required by the Texas Commission on Environmental Quality (TCEQ), in this case because of the levels of a contaminant called trihalomethanes (THM).

The city is a bit chagrinned over the notices – and having to pay to mail them – because the problem that caused the concerning levels was taken care of last August.

Trihalomethanes are formed as a by-product predominantly when chlorine is used to disinfect drinking water. They are generally referred to as disinfection by-products.

They result from the reaction of chlorine with organic matter present in the water being treated. The THMs produced have been associated through epidemiological studies with some adverse health effects. Many governments set limits on the amount permissible in drinking water.

However, trihalomethanes are only one group of many hundreds of possible disinfection by-products - the vast majority of which are not monitored - and it has not yet been clearly demonstrated which of these are the most plausible candidate for causation of these health effects.

In the United States, the EPA limits the total concentration of the four chief constituents (chloroform, bromoform, bromodichloromethane, and dibromochloromethane), referred to as total trihalomethanes (TTHM), to 80 parts per billion in treated water.

Up until last August Clarksville mixed surface water from Langford Lake with well water for the city’s water supply.

Water is tested and reported to the TCEQ every quarter. Matt McAdoo, the city’s utility director, said the THM level in the third quarter of 2017 shot up to parts per billion, up from 58.2 the previous quarter.

Speculation as to the source of the THM – Langford Lake being relatively shallow and subject, especially during the warm summer months to algae growth – became moot because the city closed the water treatment plant and has subsequently decommissioned it.

The U.S. Environmental Protection Agency sets the maximum contaminant level at 80, so the third quarter reading triggered the required notifications.

The City took the water treatment plant off-line and now only uses well water, but the notices about the THM levels are still required, said McAdoo.

Unfortunately the THM readings are averaged for a full year or four quarters, said McAdoo, and despite the plant being off-line and the THM level for the last quarter of last year being 56.1 and for the first quarter of 2018 being 41.5, the running average remains high, at 103 – hence the mailed notices.

Many water supply companies mail out these notices every quarter because their water always exceeds the THM level that triggers reporting, said McAdoo.

But the city wants to explain why they are still required – for the time being - for Clarksville water customer, he said.

City Manager Shannon Barrentine noted that in addition to requiring Clarksville to mail out the notices - despite the source of the problem being corrected - the city has to pay for them.

Barrentine and McAdoo said that because of using an annual average the city still has two more quarters where it will have to mail out the notices.