A vague instruction for taking water samples put Bridgeport’s water system on a British newspaper’s list of 33 U.S. cities providing instructions that could lead to underestimating lead levels in drinking water.
The U.S. edition of the British newspaper The Guardian published an article earlier this month that examined instructions that can lead to distorted test results by causing testers to run the faucet before the test period, called “pre-flushing;” to remove and clean faucet filters called aerators; or to run the water slowly.
The Guardian article said the Bridgeport system, which serves Bridgeport and other towns in the Fairfield County, failed to follow U.S. Environmental Protection Agency guidelines by having its testers run water slowly, which causes less lead to be dislodged from the pipes.
The determination was based on Aquarion Water Company’s use of the word “gently” in its 2015 lead and copper sampling program instructions, according to Jessica Glenza, one of the reporters of the article.
The EPA requires water suppliers to periodically test water from a portion of their customers for lead contamination. Suppliers typically provide instructions and ask customers to take the water samples.
Aquarion’s sampling instructions tell their customers to “gently” open the cold water tap. The Guardian reasoned this could be interpreted as telling testers to run the water slowly.
John Herlihy, Aquarion’s vice president of water quality and environmental management, said the intent of the instruction was to make sure that all the water being drawn for the first sample enters the bottle and does not splash into the sink.
“Our instructions do not say to slowly fill the sample bottles,” said Herlihy. “Once the water stream from the faucet is entering the bottle, the customer can adjust the flow as appropriate to fill the bottle. Since we have already been using a wide-mouth bottle for sample collection, the rate of flow is not restricted by the bottle.”
Nevertheless, Herlihy said, more precise language would be helpful, and Aquarion plans to incorporate it into their instructions for lead monitoring in 2016, which is done from June to September. The revised language will tell customers to open the faucet as they would to fill a glass of water.
Aquarion’s instructions from 2015 clearly state that before sampling there must be at least six hours during which no water has been drawn and the aerator is not to be removed.
The EPA issued revised sampling guidelines in February 2016 that warn against “pre-flushing,” removing aerators and using narrow-necked bottles.
Marc Edwards, a professor for Virginia Tech who is part of the team addressing the water problems found in Flint, Michigan, said of all the practices that can distort lead tests, running the water slowly “is probably the least likely to mislead.”
Nonetheless, Edwards said anything that is not normal water usage can make lead in water look low during testing.
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