The Port Washington Water District listed 1.9 parts per billion as the highest detected level for 1,4-dioxane contamination in its 2018 Water Quality Report released last Wednesday.
A maximum contamination level of 1 part per billion was recommended by the state Drinking Water Quality Council in December, but no federal or state regulation has been set.
The contamination level of 1.9 parts per billion was the highest level of contamination found in any of the district’s wells and is a result of testing the well directly. Port’s drinking water is produced from a blend of Port’s wells to supply water that is less than 1 part per billion, according to Superintendent Paul Granger.
Due to the lack of regulation, the water district follows a state guideline to not exceed 35 parts per billion for 1,4-dioxane that is nonenforceable but based on current health information.
The Environmental Protection Agency classifies 1,4-dioxane as “likely to be carcinogenic to humans” through all routes of exposure. Animal studies resulted in increased tumors in the gall bladder, liver and nasal cavity after exposure to the contaminant, according to the federal agency.
Granger said he believes the contaminant represents a minimal risk and one would need to be exposed chronically for a long period of time, but the district is taking a conservative approach and working to control and minimize exposure.
The contaminant entered the environment through its use as a solvent and in textile processing, printing processes and detergent preparations, the water district’s report said.
A field study to treat 1,4-dioxane in the district’s three wells in Christopher Morley Park in Roslyn is expected to begin in the summer or late spring, David Brackett, chairman of the water district’s board of commissioners, said in an interview last month.
Granger said the district is already conducting bench testing in which water samples are sent to the wellhead manufacturer’s lab to analyze, which is a precursor to the field study. Results from the field study will be used to design the district’s treatment plan.
Brackett said the water district began exploring a treatment system over a year ago “when 1,4-dioxane hit everyone’s radar screen.”
The district tries to stay ahead of the curve and wanted to test the treatment before everyone is scrambling for the system, which is available from only a limited number of manufacturers, the chairman said.
He said two of the district’s wells in Morley Park tested below what the district projects the adopted maximum contaminant level to be and the third slightly higher, but the latter is used sparingly by the district.
The purification technology currently used on the district’s wells does not treat for 1,4-dioxane, while the incoming technology is not suitable to treat any contaminant besides 1,4-dioxane. Therefore, the two systems will need to run simultaneously.
Brackett said that after both systems run in conjunction with one another, the district will conduct onsite testing to confirm that the 1,4-dioxane treatment does not have any adverse effects on the treatment of other contaminants.
The Port Washington Water District contracted D&B Engineers and Architects, a New York-based environmental engineering and architectural company, for the work and will pay an amount that is not to exceed $74,100, according to minutes from the March meeting of the district’s Board of Commissioners.
Christopher Morley Park is also home to a well owned by the Roslyn Water District, Brackett said.
According to the Port Washington Water District’s website, the district drilled two wells in Christopher Morley Park in the late 1960s. The wells were built outside the Cow Neck Peninsula, where Port Washington is located, to ensure that Port’s drinking supply is not affected by saltwater intrusion.
The website says the Christopher Morley Park wells now account for two-thirds of the district’s water supply.
The 2018 Water Quality report is available on the district’s website and will be mailed to all of the district’s 30,000 water consumers in the villages of Manorhaven, Baxter Estates, Port Washington North, Flower Hill, Plandome Manor and portions of Manhasset.
The report said the water district conducts 13,300 tests on the drinking water each year and samples are collectively analyzed for more than 140 different parameters.
The tests are also performed by a third-party testing facility and examined by the Nassau County Department of Health, which the water district said repeatedly confirms “that the water being delivered to homes and businesses meets and surpasses all drinking water standards currently established by federal, state and local regulators.”
Many of the other contaminants found in the drinking supply are naturally occurring, such as calcium, iron and magnesium.
The Port Washington Water District will host a meeting for the community where it will provide a comprehensive water presentation and field questions on May 15 at 7 p.m. at Protection Fire Engine Company at 14 S. Washington St. in Port Washington.