by Sean F. Driscoll, originally posted on July 3, 2016

FALMOUTH — The town has issued a notice that a drinking water sample taken in Woods Hole exceeded a contamination threshold for trihalomethanes, a byproduct of the water being disinfected with chlorine, for the third time since December.

The June 17 sample from 211 Nobska Road, one of eight sampling locations across town, showed the running annual average of trihalomethanes, or TTHMs, was 83.3 parts per billion, according to the notice. The maximum level allowed by state law is 80 parts per billion. Although there is no immediate risk, data suggests that some people who, over many years, drink water containing TTHMs may experience problems with their liver, kidneys or central nervous system and may have an increased risk of cancer.

The water is treated with chlorine to counteract the effect of organic material in the water supply, which comes from Long Pond. The TTHM threshold was exceeded at the same location in December and March, according to the notice. The completion of the new water treatment plant next year will remove the organic material in the water and, therefore, lower the byproducts.