Long Island water providers have raised rates and applied surcharges...

Long Island water providers have raised rates and applied surcharges to pay for expensive treatment systems. Water providers have estimated it could cost $840 million to build and maintain systems to treat dozens of wells. Credit: Newsday/Steve Pfost

A newly published paper from Stony Brook University researchers suggest that likely human carcinogen 1,4-dioxane has found its way from unsewered homes into Long Island's aquifer.

Household products in homes are contributing to the problem, according to the paper, but new technology might be a way to protect groundwater from future problems. The research found that a low-cost treatment system using sand and wood chips could cut the pollution.

Researchers found "nitrogen removing biofilter" systems — sand on top of wood chips — lowered levels of the chemical 1,4-dioxane in wastewater by 56%, according to the paper published in the journal Science of the Total Environment.

Levels of the human-made chemical 1,4-dioxane increased more than tenfold on average as it passed through households' taps to their septic systems, likely from household products such as detergents and soaps that have trace amounts of the chemical, according to the study.

The presence and release of 1,4-dioxane to groundwater from septic systems had not been previously studied, according to the paper.

"The results are very surprising and at the same time encouraging as 1,4-dioxane is expected to resist natural degradation processes and are not removed efficiently by filtration," said Arjun Venkatesan, a coauther and associate director for drinking water initiatives at New York State Center for Clean Water Technology at Stony Brook University. Researchers announced the finding Friday in an online news conference.

Adrienne Esposito, executive director of environmental group Citizens Campaign for the Environment, said the findings reaffirm efforts to require manufacturers to eliminate 1,4-dioxane in their products.

On Long Island, water providers have raised rates and applied surcharges to pay for expensive treatment systems. Water providers have estimated it could cost $840 million to build and maintain systems to treat dozens of wells.

Researchers said they hadn't studied the method to treat drinking water, but are looking at combining the microorganisms that break down 1,4-dioxane with traditional filtration methods, Venkatesan said.

"New York became the first state in the nation last year to set a drinking water standard for 1,4-dioxane. The chemical has been widely found in Long Island’s drinking water following a 2017 federally mandated survey. Most of the contamination was found in groundwater near industrial sites, where the chemical has been used in solvents.

But trace amounts also have been found in household products, like detergents and shampoos. New York is requiring manufacturers to phase out the presence of 1,4-dioxane in household products by 2023.

Dennis Kelleher, a spokesman for the Long Island Water Conference, which represents water providers, said, "The results of this study may also lead to new technology developments that could remove 1,4-dioxane directly from drinking water. With that said, much more research will be needed to evaluate its long-term potential as a viable treatment technology for the future."

Thomas Mohr, a California scientist who co-authored a book on 1,4-dioxane, said research "clearly shows just through the presence in unwanted products, Long Islanders are adding 1,4-dioxane through the system."

But he believed it would be difficult to use the technology in the wastewater to treat drinking water. "It's not practical to use at production wells," he said.

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