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On October 2, 2020, MassDEP published final regulations establishing a drinking water standard, or a Maximum Contaminant Level (MCL), for the sum of six per- and polyfluoroalkyl substances (PFAS). The MCL is 20 parts per trillion (ppt) for what the regulations call PFAS6, or the sum of six PFAS compounds: perfluorooctanesulfonic acid (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluoroheptanoic acid (PFHpA), and perfluorodecanoic acid (PFDA).
Additional MassDEP regulations for testing of PFAS in the environment are likely in the future as scientific studies are conducted and the understanding of these chemicals increases. The Town of Nantucket has been and will perform all testing as required by MassDEP. The Town may also perform testing as recommended by our professional and licensed consultants to address specific situations.
The Town of Nantucket, Nantucket Memorial Airport and Wannacomet Water Company along with MassDEP are working together to coordinate PFAS related activities.
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Yes. MassDEP began a Private Well PFAS Sampling Program in November 2020. In February 2021, the Town of Nantucket is being considered to be added to this program. The program selects a representative number of private wells, provides sampling kits to well owners, and pays for the laboratory analysis costs of the PFAS samples. The private well owner is responsible for collecting the sample.
MassDEP will select which wells will be sampled based on priority factors including geographic distribution throughout the town, proximity to potential sources of PFAS, and available funding. Applying for the program does not guarantee your well be included in the program. To apply for consideration, well owners can submit a Private Wells PFAS Sampling Program “Notice of Interest Application Form” on MassDEP’s website.
Wannacomet Water Company public water supply well sampling results have been below the Maximum Contaminant Level (MCL) Massachusetts Department of Environmental Protection (MassDEP) set as safe for PFAS in drinking water, with most wells showing no PFAS. Wannacomet public water supply wells draw water from below confining units. A confining unit may help prevent PFAS from moving vertically, deeper underground where the Wannacomet public water supply well screens are located. For comparison, most private residential (domestic) wells are screened in the upper Unconfined Aquifer, thus withdrawing groundwater from above the confining unit.
Groundwater sample results have been reported by Nantucket Memorial Airport for on-airport shallow monitoring wells and adjacent residential drinking water wells, the Town’s Wannacomet Water Company public water supply wells, and by a limited number of private residents. This data is not a complete picture of PFAS in the Island’s aquifer. The Airport is continuing to advance its investigation through ongoing sampling and source identification activities. The Town is developing a groundwater sampling program, and the Siasconset Water Department will test their wells by October 1, 2021. The Town sampling program is scheduled to begin in Spring 2021 and will focus on the landfill site. Once we have that information, we will better understand if PFAS impacts the groundwater aquifer.
An aquifer is underground layer of water bearing rock and/or granular materials from which water can be extracted using a well.
A confining unit is relatively dense and contains impermeable materials, such as clay, that may prevent transport of groundwater and pollutants deeper into the subsurface.
Whether you can hook up to public water depends on location and discussions with the Town. If there are existing Town water lines on your street, the process to install a new water service to a property from that existing line may be easier and cheaper. If a property is located in a part of Town without public water lines, it is more difficult. Your location, how close you are to existing water lines, funding, and conditions below the surface may all factor into if you can hook up to public water. For more information please contact Town Administration, contact information is provided at the end of this Fact Sheet, or the Wannacomet Water Company directly.
No. There is no specific regulation of PFAS in a Zone II aquifer wellhead protection area (refer to glossary) relative to septic systems. However, the MassDEP Title 5 program and land use controls offers general protection to Zone II aquifer areas. Local Boards of Health and MassDEP are the regulatory authorities for septic systems. The Town of Nantucket’s Septic System Resources website (see call-out box) has helpful resources for you to ensure you are doing your part to protect the Island’s resources, including the Zone II aquifer wellhead protection area.
If homeowners are interested PFAS sampling and testing at their own election, there are laboratories you may contact and request pricing. Here are a few companies that are known to have done PFAS testing on Nantucket. This is not a complete list of all available firms and this list is not to be considered an endorsement for any particular company. Listed alphabetically:
If there are other firms that may be added to the list, please send the information to PFAS@nantucket-ma.gov
No. PFAS sampling results from leachate (liquid coming out of landfills into the ground) or co-compost (leaf/yard waste mixed with municipal solid waste and dewatered sludge (residuals) from the WWTF that are processed through a composter to create biosolids) should not be compared to regulatory or other health-based PFAS standards for soil or groundwater. The risk for each type of media is different, so the standards for one type cannot apply directly to another type. MassDEP is developing screening levels for land application of soil amendments, including biosolids, which would apply to co-compost. FAQs #9 and #10 have more information on the health risk to plants growing in soil with co-compost. Note that co-compost has not been available to the public since August 2019.
As of March 2021, we do not know yet. The Town has not sampled private drinking water wells below the landfill site. The Town with CDM Smith is developing a groundwater sampling program to better understand how PFAS from the landfill impacts groundwater. The Town will let the community know when the program begins.
There will be. The Town with CDM Smith is developing a program to better understand the PFAS in the WWTF and landfill site, as recommended in the Town-wide Preliminary Assessment and Planning Approach Report. The program may include collecting PFAS samples at the WWTF and landfill. The Town will let the community know when the program begins. There are currently no MassDEP or U.S. Environmental Protection Agency (USEPA) guidelines for WWTF or landfill sites at this time. However, both agencies are moving forward to include PFAS in Wastewater National Pollution Discharge Elimination System (NPDES) Permits. For more information check out MassDEP’s website at: https://www.mass.gov/info-details/per-and-polyfluoroalkyl-substances-pfas#pfas-in-wastewater-facilities-with-npdes-permitted-discharges-
PFAS are a group of man-made chemicals used since the 1940s. PFAS were used to manufacture commercial products and firefighting foam. Some PFAS are no longer used. The potential source of PFAS present at the Town landfill, such as in waste water treatment residuals and municipal solid waste, are primarily from use of household cleaning products, food packaging, clothing, and beauty products that contained PFAS.
In 2019, Massachusetts Department of Environmental Protection (MassDEP) recognized the need for more information on PFAS characteristics in wastewater treatment residuals. Prior to 2020 on Nantucket, such residuals were mixed with municipal solid waste and leaf/yard waste to be used for compost. Waste Options, the Town Contractor, collected compost samples in 2019 to maintain a proactive approach to environmental quality on the island. Specific PFAS sampling protocols were not established at that time.
The data received could not be readily assessed, as MassDEP has not yet issued criteria to evaluate risk associated with PFAS in wastewater treatment residuals or compost. Further, it is recognized that sampling was not conducted in accordance with current protocols. The Town and its Contractor Waste Options are now performing quarterly monitoring of PFAS in accordance with the recent MassDEP Approval of Suitability (AOS) permit requirement updates. Note that starting in 2019, wastewater residuals and municipal solid waste stopped being used to prepare compost for Town-wide use.
(i.e. compost being pulled from the dump and new more precise tests being taken)?
The Town is currently evaluating island-specific risk to PFAS, including compost use, and subsequent risk mitigation actions, as warranted. It is essential that subsequent actions be based on sound science and collection of samples using MassDEP sampling protocols. The Town and Contractor, Waste Options, agree that the 2020 MassDEP Approval of Suitability (AOS) permit compost sampling PFAS results will be used to discuss risk mitigation actions with the Board of Health and other public stakeholders.
As part of the Town’s public outreach strategy, the PFAS results from the independent sampling event and island-specific risk to PFAS will be made available to the community. A fact sheet on the island-specific risk to PFAS is scheduled to be released next month. The Town is also collaborating with North East Biosolids and Residuals Association (NEBRA) to prepare and distribute educational materials pertaining to PFAS in biosolids and compost, and potential use. The Town will continue to be compliant with MassDEP PFAS regulations as they evolve and will transparently communicate status to the public.