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.
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.
Even without the wells, the city can meet residents’ water needs during cold-weather months, said Michael Colangelo, Glen Cove’s water service foreman.
“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.
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.
The source of the Roslyn well contamination was never found, despite “thorough investigations,” DEC officials said.
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.