Study Highlights Breadth Of Dioxane Contamination

Utility officials on Long Island are working to expand their treatment capabilities to ward off the threat of dioxane contamination.

Dioxane appears to be a widespread contaminant on the island.

A report released last month by the Citizens Campaign for the Environment showed that samples have turned up unsafe levels of the manufacturing solvent in multiple Long Island communities, CBS New York reported. The report included an interactive map highlighting sites of dioxane contamination.

The report noted that 1,4-dioxane is never found in nature, and that federal regulators say it is likely carcinogenic. Hair products, detergents, and cleaning products sometimes contain this contaminant. The U.S. EPA says 1,4-dioxane poses a cancer risk in drinking water at levels above 0.35 μg/L, according to the report.

“Detections above this amount have been found within 39 separate water districts and distribution areas across Long Island, serving about two million Long Islanders,” the environmental report said.

The dioxane threat in Long Island came under scrutiny this year after samples at a Hicksville well registered the contaminant at 33 parts per million, CBS New York reported.

“Water testing in Hicksville turned up the highest level of 1,4-dioxane found in the entire country,” Newsday reported.

The well is now used for emergency purposes only, but major concerns remain.

“Collectively, Long Island's water supply has the highest levels of the chemical in the state, levels that are considerably higher than the national average,” Newsday reported.

The Suffolk County Water Authority is working on an effort to remove more dioxane from the supply. The utility has plans to build the first advanced oxidation process treatment system in the state, according to a statement from the utility issued in January.

The statement explained the utility’s plans for treating this contaminant:

This past fall, both New York State and Suffolk County approved our application to build a full-scale Advance Oxidation Process treatment system to remove 1,4-dioxane. Based on our small-scale test run, we are anticipating the full-scale system, which is scheduled to be put into operation this spring at our Commercial Boulevard pump station, to remove approximately 97 percent of detected 1,4-dioxane from groundwater. What’s left post AOP will then be treated with GAC to remove any harmful compounds. We will then be required to supply the state and county with data for at least a year before hopefully putting the system into use.

The EPA points to the difficulty of treating the contaminant, as well. Dioxane in water is tricky to address, according to the EPA in its handbook on how to handle the contaminant. The handbook notes that 1,4-dioxane is “fully miscible in water.”

“As a hydrophilic contaminant, it is not, therefore, amenable to the conventional ex situ treatment technologies used for chlorinated solvents. Successful remedial technologies must take into account the challenging chemical and physical properties unique to 1,4-dioxane,” it continued.

The handbook cites a total of 15 projects where 1,4-dioxane was treated in groundwater. Twelve of the projects used ex situ advanced oxidation processes.