Elevated disinfection byproducts trigger Cocoa water violation
by Jim Waymer, originally posted on May 31, 2016
Brevard County’s largest water supplier recently violated federal drinking water standards for a group of byproducts of disinfection linked to increased lifetime cancer risk.
But the contamination from total trihalomethanes (TTHMs) is nothing a pitcher filter and a little air time can’t cure.
“Carbon filters will remove them,” said Joel Sivils, Cocoa’s water quality supervisor. “Probably the best in-home thing to do is the carbon filters.”
Leaving an open water pitcher in the refrigerator overnight also allows the byproducts to dissipate.
The city’s supply — which serves about 80,000 connections in central Brevard County, including Kennedy Space Center, Port Canaveral and Patrick Air Force Base — recently reached an annual running average for TTHMs of 83.6 parts per billion.
Solving disinfection byproducts led to unintended consequences
Violations occur when the running average of quarterly tests tops 80 parts per billion for the total of four trihalomethanes or 60 parts per billion for five haloacetic acids, another group of disinfection byproducts. One part per billion is comparable to an ink drop into an Olympic-size swimming pool.
A public notice informing customers has been trickling into households over the past few weeks.
According to the notice, one of 12 monitoring sites in the city (at the 5200 block of W. King St.) tested at:
- 93.3 parts per billion on May 1, 2015;
- 94.9 parts per billion on Sept. 4, 2015;
- 62.4 parts per billion on Nov. 3, 2015;
- 95.9 parts per billion on Feb. 1, 2016; and 71.3 parts per billion on Feb. 16 (average 83.6).
That brought the annual running average to 83.6 parts per billion.
TTHMs are the sum of the concentration of chloroform and three other trihalomethane compounds.
TTHMs periodically exceed the federal long-term limit at Brevard utilities. Trihalomethanes and other byproducts form when disinfecting chemicals such as chlorine are added to kill the much more acute health threat from viruses, bacteria and other microbes.
Disinfection byproducts form when residual chlorine reacts with rotting leaves, algae or other organic matter.
Sivils said the exact cause of the recent higher levels of TTHMs has yet to be determined.
Federal risk assessments show water with high levels of disinfection byproducts is safe to drink in the short-term, but exposure to high levels over decades can increase risk of bladder, colon and several other cancers. Some recent studies have found an association between a pregnant woman’s exposure to chlorination byproducts and increased risk of low birth weight and birth defects.
The byproducts lurk everywhere, from the chlorinated water that irrigates lawns, golf courses and parks, to sewage that seeps from septic tanks into groundwater supplies. They even form in morning coffee when chlorine reacts with the ground organic beans.
Showering, hand washing and swimming can inflict even higher doses of the chemicals than drinking water.
The increased cancer risk happens with long-term exposure.
The U.S. Environmental Protection Agency estimates drinking a half-gallon of water containing 100 parts per billion of trihalomethanes daily for 70 years could result in three more cases of cancer per 10,000 people.
Cocoa is working on the disinfection treatment to lower the TTHMs, the public notice said.
The city disinfect the water with chlorine, then adds ammonia, to form compounds called chloramines that reduce disinfection byproducts.
The time it takes water to travel from the treatment plant to taps can determine the concentration of these chemicals.
Utilities install costly reverse-osmosis systems to filter out the organic matter that causes the byproducts to form. Treatment plants also can use expensive ozone or ultraviolet light treatment.