Per- and Polyfluoroalkyl Substances (PFAS)

PFAS refer to a group of man-made chemicals known as Per- and Polyfluoroalkyl Substances that have been used since the 1940s in numerous household and industrial products. PFAS have been used in carpets, fabrics, clothing, food packaging, pots and pans, and personal care products to repel water, resist stains and grease, and resist temperature changes. There are thousands of varieties of these chemical compounds. PFAS are persistent in the environment which means that they don't break down easily and almost everyone has some levels of these chemicals in their bodies. In the environment, PFAS has been found in residential septic systems, near airports where certain firefighting foams were used, near factories that used these chemicals, on land where the application of sludge and septage has occurred, and in landfill leachate.

If you have questions about blood testing or health effects from PFAS, please contact the Maine Center for Disease Control and Prevention (CDC) and ask to speak to a toxicologist at 866-292-3474 (toll-free in Maine), 207-287-4311, or Maine Relay 711. If you are concerned about a known PFAS exposure, it is best to talk with your doctor to decide whether to test for these chemicals.

Sludge and septage are created as a result of what goes down the drain. Many products that we use in our daily lives contain PFAS, and therefore a certain level of PFAS goes down the drain into our wastewater. During the process of treating wastewater, PFAS can be concentrated in the resulting sludge. Household activities such as washing laundry or textiles that contain PFAS, or cleaning non-stick pans made with PFAS are just two examples of how PFAS can easily get into our wastewater stream. Since the late 1970’s sludge and septage waste streams were often land applied as a beneficial method for adding nutrients back into the soil. Land application of sludge or sludge-derived products occurred commonly at farms or areas used for landscaping throughout the United States and was perceived as a positive practice. In Maine these practices were licensed to ensure that concentrations of metals or other organic compounds did not compromise soil health. PFAS were not taken into consideration as part of the licensing process until 2019 as it was not fully understood before then that PFAS in sludge could impact public health and the environment.

When deciding which wells to sample, the Department considers site-specific information including known or potential sources of PFAS contamination, direction of groundwater flow, and the private drinking water well’s proximity to licensed land application sites.

There may be a few reasons why your neighbor’s well was sampled, but your residence was not. Your well may be just outside an area of investigation and results of nearby wells that were part of the investigation may have shown that PFAS were not detected. It also could mean that your well may not have been included in the most recent round of sampling but may be sampled in the near future. DEP has established a prioritization system to decide where to sample for PFAS contamination in wells. First, DEP takes into consideration information about known or potential sources of PFAS, soils, the direction of groundwater flow, and existing test results to determine the areas that are likely to have the highest potential risk. Once these areas are identified, DEP conducts a phased approach to sampling which may be broadened over time based on an evaluation of results. This means that sampling starts closest to the areas identified as highest potential risk, and then the radius of investigation is expanded as needed. How far out the sampling continues is based on an evaluation of results including whether there have been any exceedances of the standard. If sample results get lower and lower as sampling continues outward, sampling will be reduced.

Yes, DEP encourages homeowners that are interested to sample their own water supply if certain sampling protocols are followed, and a Maine-certified laboratory is used. Specific sampling requirements must be followed to avoid potential cross-contamination of the sample. Please read DEP's PFAS Water Sampling for Homeowners or email the DEP with questions or to obtain technical assistance.

In locations where it is determined that concentrations of PFAS in private drinking water wells exceed Maine’s interim drinking water standard for the sum of 6 PFAS (PFOA, PFOS, PFNA, PFHxS, PFHpA, and PFDA), and contamination can be tied to a DEP-licensed sludge or septage land application site or other remediation-type sites, DEP will work with homeowners to ensure that they have clean water to drink. In these circumstances, DEP will provide homeowners with bottled water until a filtration system can be installed and determined to be effective. A Project Manager will be in touch with you to determine how much bottled water needs to be delivered to your home and to begin the process of getting a filtration system installed.

As an interim measure until an alternative approach is available, and subject to available funding, the Department will pay for the installation and maintenance of filtration systems on private residential water supplies, and certain other water supplies, where the DEP can link contamination to the land application of sludge or septage or other remediation-type sites. Filtration systems will generally consist of either two granular activated carbon treatment units or ion exchange resin-based treatment units with a water meter. Water softener systems may also be installed to maintain appropriate treatment depending on each home's specific water quality.

Subject to available funding, DEP is paying for the installation and maintenance of the filtration systems for private residential water supplies and certain other water supplies where Maine's interim drinking water standard has been exceeded and DEP can link contamination to the land application of sludge or septage or other remediation-type sites. DEP is pursuing additional funding and other remedies for a long-term sustainable strategy and to ensure affected homeowners have safe water to drink.

The DEP will regularly monitor the effectiveness of the systems in treating PFAS and provide the results to each homeowner. Sampling ports will be added to the system so water can be sampled in multiple locations: before entering the first filter, between the two filters, and after the water exits the filtration system to verify that the system is working correctly and effectively.
Depending on the initial concentration of PFAS in your well, the DEP will generally sample on a quarterly or semi-annual basis for a year or so to get an understanding of how the filter system works to reduce the concentrations of PFAS. This may seem like a lot of samples, but the results will determine how well the system is operating and how often the filter media will need to be changed over time. After the first year of sampling, a different frequency may be developed to monitor the filtration system over the long-term.

Maintenance of the system will be conducted periodically by DEP or by its designated contractor based on a review of periodic sampling data. Maintenance will occur based upon availability of funding and may include repairing or replacing components of the treatment system to ensure it is operating effectively.

Where appropriate and so long as funding is available, the DEP or its designated contractor will provide salt for water softeners and spare sediment filters. The property owner may assume responsibility for some routine maintenance, such as adding salt for water softeners and changing sediment filters as needed.

Responsibilities for maintenance are outlined in the Water Treatment System Filter Agreement that each homeowner is required to sign in order to obtain installation, maintenance, and management of its filtration system.

Property owners are required to sign a Water Treatment System Filter Agreement. The agreement outlines the basic responsibilities of both the property owner as well as the DEP and it grants the DEP access to monitor and maintain the filtration systems. The agreement protects both DEP and the homeowner by establishing clear and consistent expectations that both parties must follow to ensure an effective treatment system is installed, monitored, and maintained.

Once a filtration system has been installed, DEP will collect water samples to demonstrate that your water is safe to drink. If you elected to receive bottled water delivery, that will continue until DEP informs you that your treatment system is working properly. Bottled water delivery will then be discontinued.

The effectiveness of a filtration system depends on many different factors including input contaminant concentrations, water use, filter size, and type of filter. In general, the filter systems being installed are dual stage carbon filters. This means that two canisters filled with carbon are being installed so that contaminant concentrations can be monitored before the first filter, after going through the first filter (between sample), and after going through the second filter. This is all done before the water is deemed safe to drink. The between sample is able to tell us whether any type of contaminant will breakthrough through the first filter and helps us to decide when to replace the filter media. In a few systems, the filter media has had to be replaced at a more frequent schedule than anticipated; however, the sample taken after the second filter shows the water is still safe to drink. This stresses the importance of monitoring and maintaining a system regularly.

The DEP's current focus is on providing safe water to drink for those households that already have wells installed and are drinking impacted water. DEP can provide technical assistance to you if you’re concerned about installing a well in a particular area or if you would like general information about the kinds of DEP-licensed sites near your property. Please email us with your questions.

There are several water treatment vendors throughout Maine that install systems to treat for PFAS. The Maine Center for Disease Control and Prevention lists several water treatment professionals on their website.

While DEP is not able to provide a recommendation for a particular vendor, there are a few considerations for selection including treatability and certification. EPA's Drinking Water Treatability Database is a useful tool that provides information on the control of contaminants in drinking water. You can use the database to search for PFAS and evaluate the different treatment processes that have been shown to be effective in treatment for several different kinds of PFAS.

The National Sanitation Foundation (NSF) certifies filters that can reduce two PFAS compounds, PFOA and PFOS. NSF is an independent, accredited organization that tests and certifies products and systems to protect and improve human health. To find products certified for reduction of PFOA and PFOS by NSF International, visit NSFs certification listings. NSF International verifies that the contaminant reduction claims for PFOA and PFOS shown on the label are true; the system does not add anything harmful to the water; the system is structurally sound; and the product labeling, advertising, and literature are not misleading.

DEP understands that homeowners may have concerns about eating vegetables grown in or near at-risk areas; however, our current focus is to provide safe drinking water for homeowners with impacted wells. Because there is limited funding, DEP is not providing testing services for residential garden soil at this time. However, DEP has developed a Homeowner’s Guide to Soil Sampling for PFAS. Homeowners can conduct their own sampling, but generally the DEP encourages homeowners work with an environmental professional to ensure they get the most useful site-specific results possible.

Evaluating and addressing PFAS impacts in soil can be more challenging than evaluating and addressing PFAS contamination in drinking water. This is because there is no single soil standard to compare against to determine whether levels of PFAS are safe or unsafe in soil. In order to evaluate whether PFAS poses a health or environmental risk in soil, the function and use of property must be considered. For example, if a property is used for agriculture, the impacts of PFAS in soil are likely to be very different than the impacts of PFAS in soils that are located on property associated with industrial activity. Because the function and use of properties vary, each location must be evaluated on a case-by-case basis to determine the likelihood and possibilities for exposure as well as impacts to the environment. As a starting point, the DEP assesses the known and anticipated use and function of the soil in a location that has been sampled, and compares results against DEP’s Remedial Action Guidelines (RAGs), which are guidelines (non-enforceable) to evaluate whether contaminants at certain levels are likely to pose a risk to human health or the environment given specific exposure scenarios. RAGs are derived using scientifically accepted toxicological values and are reviewed carefully in conjunction with the Maine CDC, the state’s experts on health and exposure risks.

After a site has been sampled and evaluated against the RAGs, where levels of PFAS are elevated, the DEP will share information with the property owner(s) and other appropriate state agencies to help determine if additional steps need to be taken. For example, information about PFAS in soil at active farms is shared with the Department of Agriculture, Conservation and Forestry’s PFAS program. Information about other soils that may pose risks of exposure may be shared with the Maine CDC, or other appropriate state agencies.

At active farms, DEP will share soil and groundwater test data with the Maine Department of Agriculture, Conservation and Forestry. They will then determine whether agricultural-specific sampling is warranted.

If you have questions about PFAS in your vegetables, please contact the Maine CDC at 866-292-3474 (toll-free in Maine), 207-287-4311, or Maine Relay 711 and ask to speak to a toxicologist who can explain more about the uptake of PFAS in plants.