The city of Glen Cove has shut two of its five drinking water wells after elevated levels of the chemical Freon 22 were discovered.
City officials are studying whether to spend millions of dollars on equipment to remove Freon 22, which is commonly found in air conditioners and other cooling equipment, and are mulling measures to prevent summer water shortages.
The city is the third Long Island public water agency in the past five years to close a well because of Freon 22. The Roslyn Water District reopened two wells last year after installing contaminant-removing air strippers, and the Jericho Water District has had a well offline since July as officials study possible solutions, officials with the two districts said.
Health effects on humans of Freon 22 in drinking water are unclear, but studies in laboratory animals have shown that exposure to high levels of airborne Freon 22 cause nervous-system and heart problems, according to the state Department of Health.
New York prohibits concentrations of Freon 22 in drinking water of greater than five parts per billion. The chemical is in roughly 6 percent of about 1,000 operating public wells on Long Island, although usually in levels far below the state limit, said Paul Ponturo, senior water resources engineer at Melville-based H2M, a consultant for water systems across Long Island.
The two closed Glen Cove wells reached concentrations as high as 8.2 parts per billion.
The Nassau County Department of Health ordered the closure of one well on Nov. 1, after a level of 4.1 parts per billion was registered. The county typically requires wells to close if Freon 22 levels reach 4 parts per billion, “out of an abundance of caution,” said health department spokeswoman Mary Ellen Laurain.
The county ordered the second well closed on Jan. 17, after a reading of 6.6 parts per billion. Tests consistently have shown that no water distributed to homes or businesses had high Freon 22 levels, city and county officials said.
The Jan. 17 county directive states the city “should anticipate detections of Freon 22” in a third well that is in the same area off Duck Pond Road as the other two, which could mean an eventual shutdown of that well.
Even without the wells, the city can meet residents’ water needs during cold-weather months, said Michael Colangelo, Glen Cove’s water service foreman.
But water use surges in the summer when residents water lawns, and if two or more wells are out of service, residents and businesses may not have enough water unless the city expands existing restrictions on the hours and days residents can water lawns, Mayor Timothy Tenke said.
If that doesn’t reduce use enough, the city could buy water from a neighboring supplier, but “that’s really a last resort thing,” Tenke said. “Buying water from another municipality is extremely expensive.”
City officials said they hope to reopen a well that was closed in 2011 because of structural problems and Freon 22 levels just under the state limit. A Dec. 28 report from Woodbury-based D&B Engineers and Architects, P.C., estimated that installing an air stripper to that well to remove Freon 22 and making repairs would cost more than $4.7 million. Construction would take about 10 months, the firm estimated.
An air stripper for the three Duck Pond Road wells could cost $7 million to $10 million and take up to three years for installation, Colangelo said.
The state Department of Environmental Conservation has started investigating causes of the Duck Pond Road well contamination, said Karen Gomez, the DEC’s regional engineer for water and remediation.
Finding the source of Freon 22 can be difficult. The source of the Roslyn well contamination was never found, despite “thorough investigations,” DEC officials said. The state is trying to identify the source of contamination in Jericho.
One way the chemical gets into groundwater and eventually into wells is through leaks in the hundreds of underground cooling systems across Long Island, Ponturo said.
And groundwater moves over time, so “the source could be decades ago and could be thousands of feet away,” Ponturo said.