Emerging contaminants are substances being discovered in drinking water sources throughout the country. Every five years, the Environmental Protection Agency (EPA) puts out a list of a maximum of 30 unregulated contaminants that water providers are required to test and monitor. This action stems from the agency’s Unregulated Contaminant Monitoring Rule (UCMR), which is a program to collect data for contaminants that are suspected to be present in drinking water and do not have health-based standards set under the Safe Drinking Water Act (SDWA).
1,4-dioxane and PFOA/PFOS were on a recent UCMR list which has led to detections in water sources throughout the country. 1,4-dioxane specifically has been detected in 70 percent of Long Island’s water wells, including the Plainview groundwater wells at levels ranging from 0.19 to 11 parts per billion (ppb).
The Plainview Water District (PWD) has proactively taken measures to pilot our affected Well Sites and purchase AOP equipment for immediate treatment ahead of an expected MCL for 1,4-dioxane from the NYSDOH. We have secured funding in the form of a Bond from the Town of Oyster Bay while continuing to seek out grants to offset these costs for the benefit of our customers. PWD expects to have AOP treatment projects completed at 4 of our 5 impacted sites in 2020-21. This advanced planning will place the District in a very favorable position to implement wellhead treatment as quickly as possible to meet consumer demand and comply with regulations.
On August 26, 2020, the New York State Department of Health (NYSDOH) finalized a set of MCLs for 1,4-dioxane, PFOA and PFOS.
- 1,4-Dioxane MCL is set at 1.0 ug/L or 1 part per billion
- PFOA and PFOS MCL’s are set at 1 ng/L or 1 part per trillion
While the state health department has spent the last two-plus years developing the MCLs for 1,4-dioxane, PFOA and PFOS—now the strictest standards in the nation— the Plainview Water District (PWD) has been working aggressively to implement treatment for these contaminants. The District’s efforts began in 2018 and have included:
- Completed piloting advanced treatment technologies for the removal of 1,4-dioxane through a grant obtained from the Center for Clean Water Technology (CCWT) at Stony Brook University. This vital pilot program studied two types of Advanced Oxidation Processes (AOP) in conjunction with another District on Long Island. AOP is a proven treatment method for the removal of 1,4-dioxane from drinking water.
- Finished a pilot study on a third AOP pilot program at Plant 1 to treat for 1,4-dioxane.
- Actively piloting a fourth AOP pilot program at Plant 4.
- In total, the PWD has been awarded nearly $9 million in grant funding to date for water treatment projects, which includes treatment pilots for the removal of 1,4-dioxane, but does not include money for ongoing operations, maintenance, testing and upgrades.
- These advanced piloting and planning operations have placed the District in a position to finalize required wellhead before the regulations come into full effect so that we can continue to supply our residents with water that meets or surpasses all drinking water standards.
- Even though the availability of grant funding is still in question for future years, we continue to prepare grant applications in anticipation that more money may become available.
- Holding Polluters Accountable: The District is continuing its lawsuit against Dow Chemical, Ferro Corporation, and Vulcan Materials Company—the manufacturers of 1,4-dioxane and industrial solvents containing 1,4-dioxane. We are asking the court to hold these companies accountable for the costs of the necessary treatment equipment needed to remove 1,4-dioxane from our drinking water and the ongoing costs for operations, maintenance, testing, and compliance. Our customers should not have to pay those costs. Our attorneys have filed the necessary motions and paperwork, but no trial date has been set at this time.
- Pursuing any and all potential funding sources to keep costs of needed treatment upgrades as low as possible for residents.
To find out more about the actions the Plainview Water District has taken in ensuring your water’s safety, please visit our Projects page.
Treating for 1,4-dioxane is possible, but it is complex, costly and can take significant time to implement. Before a full treatment system can be brought online, a pilot study must be conducted and then approved by the County and State health departments. Each well has different water quality and therefore requires a separate pilot and approval.
The first step in developing any treatment system is understanding what exactly it is that you need to treat for. This is why the Plainview Water District has placed such an emphasis on comprehensive testing. Our frequent testing gives us information that some other suppliers, including smaller size districts, may not have access to. In New York State, for example, less than 200 out of 2,200 municipal water providers submitted samples for UCMR3 (the testing under which 1,4-dioxane falls). In other words, approximately 2,000 water providers in New York State have no sampling data and do not know their 1,4-dioxane and PFOS levels.
The District has already completed all required pilot studies needed to complete the scope of the treatment systems for 1,4-dioxane. Each pilot study used a small-scale version of an AOP treatment system to test the removal of 1,4-dioxane at impacted wells. As mentioned above, pilot studies are required by New York State before any final treatment system can be approved. It is important to note that water produced through the pilot systems are put to waste. None of this water is delivered to your tap.
Treating for 1,4-Dioxane – Advance Oxidation Process (AOP)
The only system approved by state and local health departments is the Advanced Oxidation Process (AOP). AOP treatment blends raw groundwater with a low concentration of an oxidant—most commonly hydrogen peroxide—that then goes through a sophisticated ultraviolet light reactor that than destroys the 1,4-dioxane molecule.
Once groundwater goes through the AOP process, that water is than piped into Granular Activated Carbon (GAC) vessels. GAC vessels—which are industrial-sized carbon filters—remove any remaining hydrogen peroxide and other volatile organic compounds (VOC) from the water. From here, water is chlorinated, tested and then sent through the distribution system.
Piloting, the design process, health department approval and the construction bidding process for the AOP systems on Long Island has proven to take a significant amount of time. However, the Plainview Water District has taken extreme measures wherever possible to expedite implementing treatment as quickly as possible. This includes the passing of an emergency resolution to design and execute treatment. We are working with one of the country’s top engineering firms and using the world’s leading technology to help accomplish this water quality goal.
We are currently treating for 1,4-dioxane at three wells, with another three coming online in 2021.
The Plainview Water District’s commitment to provide its residents with water that meets or surpasses all federal, state and local guidelines is unwavering. With that said, it is important to know that we as water providers are not responsible for setting health standards for drinking water. Our function is to take the regulations and guidelines developed by health experts and design, implement and maintain the treatment systems required to ensure that water being delivered to a resident’s home complies with the Health Department’s strict and rigorous standards.
New York State is the only state in the country with an enforceable MCL for 1,4-dioxane. According to state officials, the proposed standard is meant to ensure that levels of the contaminant in our drinking water “never rise to the point of causing a public health risk.”
Testimony provided by the Nassau County Health Department in 2019 stated “Based on the testing to date, the current levels of 1,4-dioxane in Nassau County drinking water do not represent an acute or short-term health risk, but may slightly increase the risk of cancer after a lifetime of exposure. The EPA’s risk assessment for one in a million cancer risk in drinking water is set at 0.35 ppb. Other states have developed drinking water and groundwater guidelines ranging from 0.3 ppb to 787 ppb.”
The EPA’s Drinking Water Standards and Health Advisory statement states an increased lifetime cancer risk of one in 1 million assuming consumption of 2 liters of water per day every day for a lifetime (70 years) at a level of .35 ppb. More information from the EPA can be found under the “Additional Resources” tab below.
1,4-Dioxane is a synthetic chemical historically used as a stabilizer for industrial solvents, predominantly 1,1,1-trichloroethane (TCA). Although use of TCA was phased out more than 20 years ago, 1,4-dioxane is long-lasting in the environment and is present in groundwater as a legacy of industrial manufacturing. Apart from its use as a solvent stabilizer, information disseminated by the EPA states that it is used in the manufacturing of some pharmaceuticals and may be present in some food supplements, and food containing residues from packaging adhesives on food crops treated with pesticides that contain 1,4-dioxane. It is also found in trace amounts in products such as cosmetics, detergents, and shampoos.
While we are here to speak with our residents about emerging contaminants, health-related questions are best answered by the qualified individuals at your local and state health departments. They can be reached at:
New York State Health Department
Nassau County Department of Health
Many residents ask: Can I treat for 1,4-dioxane at home with filtration? The short answer is no.
Regarding filtration systems and bottled water: at present, there are no NSF or UL certified home water treatment devices available for the removal of 1,4-dioxane. As to bottled water, regulations for 1,4-dioxane would be enforced by the Food and Drug Administration, but they are currently do not exist and we are unaware of plans to have them developed. Consuming bottled water also has its own health risks associated with exposure to micro plastics. Bottled water manufacturers may have specific information on 1,4-dioxane levels for their products, but they are not all required to test.
If you have any further questions, please reach out to the District directly at 516-931-6469 or by email at firstname.lastname@example.org.
New York State Department of Health can be reached at 1-800-458-1158 or by email at email@example.com.
Nassau County Department of Health can be reached at 516-227-9697.
More information about 1,4 dioxane can be found at these sites:
- Info on EPA Unregulated Contaminant Monitoring
- Albany Times Union – Long Island Water Conference – More Time Is Needed To Comply with Emerging Contaminant Regulations
- Consumer Reports – Should We Break Our Bottled Water Habit?
- 1,4-dioxane in Drinking Water – Guideline Technical Document for Public Consultation
- US EPA Technical Fact Sheet 1,4-Dioxane.
- US EPA Integrated Risk Information System (IRIS).
- US EPA Toxic Substances Control Act (TSCA) Risk Evaluation for Existing Chemicals
- Agency for Toxic Substances and Disease Registry (ATSDR) ToxFAQs fact sheets.
- National Institute for Occupational Safety and Health (NIOSH). “Dioxane – NIOSH Pocket Guide to Chemical Hazards”.