PFAS – short for per- and polyfluoroalkyl substances – refers to a large group of more than 4,000 human-made chemicals that have been used since the 1940s in a range of products, including stain- and water-resistant fabrics and carpeting, cleaning products, paints, cookware, food packaging and fire-fighting foams. These uses of PFAS have led to PFAS entering our environment, where they have been measured by several states in soil, surface water, groundwater and seafood. Some PFAS can last a long time in the environment and in the human body and can accumulate in the food chain.
Most people have been exposed to PFAS because of their use in so many common consumer goods. There is evidence that exposure to certain PFAS may lead to adverse health effects in humans.
The risk posed by exposure to PFAS is an emerging and evolving national concern. Maryland is focused on:
Understanding the risk through sampling, science, and assessment
Communicating the risk through public information, and outreach
Reducing unacceptable risks through appropriate funding, regulation, partnerships, and agency coordination
MDE is putting a priority on the implementation of a science-based comprehensive plan for PFAS risk that is focused first on determining whether there are locations in Maryland where there are unacceptable risks to human health associated with exposures to PFAS and whether there are locations of continuing releases of PFAS compounds. Maryland held a PFAS Science Roundtable, sponsored by the University of Maryland Center for Environmental Science in cooperation with MDE, to discuss the state of the science and to review MDE priorities for further investigations of PFAS occurrence and releases in Maryland.
Currently, there are no federal regulations (i.e. Maximum Contaminant Levels (MCLs)) for PFAS in drinking water. However, in 2016 the U.S. Environmental Protection Agency (EPA) issued a Health Advisory Level (HAL) of 70 parts per trillion (ppt) for the sum of PFOA and PFOS concentrations in drinking water. While not an enforceable regulatory standard, the EPA HAL does provide drinking water customers, even the most sensitive populations, with a margin of protection from lifetime exposure to PFOA and PFOS in drinking water.
In 2020, MDE started sampling 129 public water treatment systems for PFAS. The highest measured levels of PFOA and PFOS (i.e. those greater than EPA’s HAL of 70 ppt) were found in water treatment systems serving the City of Westminster and the Town of Hampstead. When initial sample results from these systems measured levels greater than EPA’s health advisory level, MDE worked with both water systems to take actions including: immediately taking the affected water treatment plants offline while needed confirmation samples were collected; collecting additional groundwater and finished water samples; and issuing public notices. The systems have continued to keep the affected plants or wells off-line until a proper treatment plan is in place.
That initial phase of drinking water sampling was completed and a report was issued in July 2021. For the second phase of sampling, drinking water systems were selected based on: consumer potential for long term exposure to PFAS, if present; source water vulnerabilities; interest by MDE in determining whether groundwater from confined aquifers are less likely to be impacted by PFAS; and proximity to potential PFAS sources.The report on that second phase describes the results of sampling of 65 public water systems across the state. Results for these two phases of sampling can be found in the "Additional Information" section at the end of this webpage.
Sampling for the third phase of MDE efforts to sample public water systems for PFAS began in August 2021 and is expected to continue through late spring 2022. MDE will address any elevated PFAS levels that are detected and produce a report on these results as well.
In June 2022, the EPA announced new drinking water health advisories for PFAS chemicals and that it is inviting states and territories to apply for $1 billion – the first of $5 billion in Bipartisan Infrastructure Law grant funding – to address PFAS and other emerging contaminants in drinking water, specifically in small or disadvantaged communities.
In recent years, as the risk posed by exposure to PFAS has emerged and evolved as a national concern, the Maryland Department of the Environment has placed a priority on understanding, reducing and communicating that risk. The department has done this through sampling and assessment, applying updated science and working in partnership with other agencies and local governments. This includes sampling at more than 450 community water systems, serving nearly 90% of Maryland’s population. Where high concentrations of PFAS have been found, MDE has worked with systems to find alternate sources of water. MDE is prepared to use the PFAS-specific funding under the Bipartisan Infrastructure Law to reduce the risk of exposure. MDE is also examining the best course for Maryland to take in the future regulation of these chemicals, including the possibility of proceeding ahead of the EPA in establishing an enforceable Maximum Contaminant Level for PFAS in drinking water. All of this positions Maryland well for continued progress in protecting our citizens and communities. The interim health advisory announced by EPA, which for PFOA and PFOS are below detectable limits, raises technical challenges that we hope will be resolved with upcoming regulations that will account for feasibility, costs and benefits. MDE will work with the water supply system operators in Maryland to provide guidance in making the best use of this interim health advisory.
In addition to conducting additional drinking water sampling, MDE continues to carefully monitor the EPA’s work with regard to PFAS in drinking water. As additional information is published, such as MCLs and toxicity assessments, MDE will take additional actions to reduce unacceptable human health risks with respect to PFAS. The Maryland Department of Health, out of an abundance of caution, has issued a health advisory for a specific PFAS, Perfluorohexane Sulfonic Acid (PFHxS), in drinking water in concentrations at or above 140 parts per trillion.
MDE works with the U.S Environmental Protection Agency to ensure that U.S. Department of Defense (DOD) sites in Maryland are assessed, remediated and monitored wherever PFAS are present.
DOD monitored military facilities throughout the country and in 2018 released a report on its investigation of PFAS at military bases. This report identified four sites in Maryland with PFAS contamination in groundwater: the former Fort Meade Tipton Airfield; Naval Research Lab, Chesapeake Beach Detachment; the former Navy Bayhead Annex in Annapolis; and the former Naval Research Laboratory in White Oak. Since that time, PFAS compounds have been identified at four additional military installations in Maryland: Aberdeen Proving Ground; Naval Air Station Patuxent River; Joint Base Andrews; and the former Brandywine Defense Reutilization and Marketing Office. Preliminary assessments are being conducted at the rest of the military facilities in Maryland including Fort Detrick, Forest Glen Annex, and Naval Air Station Patuxent River’s Webster Field Annex. Public hearings were held in spring 2021 on PFAS investigations at Naval Air Station Patuxent (PAX River) and the Naval Research Lab, Chesapeake Beach detachment.
PAX River and Webster Field
MDE has reviewed the soil and groundwater data obtained by the Navy at Pax River and Webster field. While no wells were impacted at levels at or exceeding the EPA PFAS health advisory level, MDE is concerned about the high levels of PFAS found in shallow groundwater and the potential for this shallow groundwater contamination to migrate to surface water and into the deeper aquifer.
In late 2020, based on verbal communication by the Navy to MDE about preliminary results from shallow groundwater sampling at Webster Field, MDE requested the Navy to take additional, immediate steps to further assess PFAS impacts and address them in the short term. These steps include: increased sampling to ensure that shallow groundwater impacts are not impacting off-site drinking water sources or surface water; more frequent sampling of on-base drinking water wells; identifying interim measures to prevent the further spread of PFAS while additional assessment and remediation are completed; developing plans to minimize future releases of PFAS at the base; and providing an expedited schedule for delineating, assessing, and remediating the identified PFAS groundwater plumes.
MDE strongly urges the Navy to immediately take these steps. MDE will continue to work with the Navy and our federal regulatory partner, EPA, to ensure necessary followup occurs to keep Marylanders informed and protected.
NRL Chesapeake Beach
An investigation at the Naval Research Lab in Chesapeake Beach identified a large PFAS plume in shallow groundwater. MDE has reviewed the data obtained by the Navy at NRL-CBD. While no wells were impacted at levels at or exceeding the EPA PFAS health advisory level, MDE will require the Navy to conduct additional characterization and assessment to determine the extent of PFAS impacts to surface water and aquatic organisms. MDE will continue to work with the Navy to ensure necessary followup occurs to keep Marylanders informed and protected.
St. Mary’s County Pilot Study
As part of its comprehensive plan, MDE conducted a pilot study in 2020 to sample and test surface water and oyster tissue for PFAS in St. Mary’s County. Results of the PFAS public health risk evaluation for recreational surface water exposure and oyster consumption showed no levels of concern. Results were significantly below MDE site-specific risk-based screening criteria for PFOA and PFOS throughout the entirety of the study area.
Fish Tissue Sampling
Maryland has for several decades monitored for certain chemical contaminant levels (e.g., PCBs and mercury) in Maryland’s recreationally caught fish. When routine monitoring indicates potential hazards to the public and environment, additional monitoring of the affected area may be conducted to verify the initial findings and identify the appropriate species and size classes associated with harmful contaminant levels. Findings from such studies are the basis for MDE’s fish consumption guidelines. In fall 2020, MDE began sampling of fish tissue for PFAS on the Eastern Shore, which includes stations in the Chester, Choptank, Corsica, Elk and Wicomico rivers and Isle of Wight and Chesapeake bays. The results from that sampling showed no levels of concern.
MDE also added two fish tissue sample locations in Piscataway Creek in Prince George’s County because Joint Base Andrews, which is located adjacent to the upper reaches of the creek, is a known source of PFAS, and an area near the mouth of the Piscataway is popular for recreational fishing. The results from the fall fish tissue collection in Piscataway Creek showed highly elevated levels of PFOS in sunfish collected west of Route 210 in the non-tidal portion of the creek. Yellow bullhead catfish were also collected at the same location and the results were mostly non-detect and similar to all other fish tissue results from the fall collection.
Because this warranted further investigation, fish tissue and water samples were collected from the area in 2021 to, among other things, validate the 2020 measurements in sunfish. MDE found elevated concentrations of PFOS in redbreast sunfish, yellow bullhead catfish and largemouth bass, leading to Maryland’s first fish consumption advisory based on levels of a PFAS compound. MDE is also expanding sample collection in the larger Potomac area downstream of Piscataway Creek between fall 2021 and fall 2022.
MDE is collecting additional, targeted monitoring for PFAS in certain specific water bodies that have been identified as having nearby potential sources of PFAS as well as sampling in locations known to be frequented by subsistence anglers and fishers.
The goal of MDE’s PFAS strategic sampling plan is to better understand the occurrence of PFAS in surface waters and fish tissue in order to reduce human health risks. MDE will assess fish tissue sampling results for PFOA and PFOS in specific waters and develop advisories when necessary to reduce human health risk. MDE will also utilize the results of the sampling to determine the need to designate waters as impaired for PFAS and to determine the need for limits on any point source discharges.
Other Potential PFAS Sources
MDE is also working to increase its understanding of other potential sources of continuing release of PFAS to the environment such as in effluent from wastewater treatment plants, including those at military installations, in biosolids produced by wastewater treatment plants (and other facilities) and in landfill leachate.
MDE recently issued a discharge permit that is the first of its kind in Maryland to require monitoring for PFAS in effluent and biosolids. That permit, for a wastewater treatment plant at Naval Support Facility Indian Head, was issued in August 2021, effective Sept. 1, 2021. MDE is also working with utilities responsible for 15 municipal wastewater facilities on plans to conduct PFAS sample collections. These facilities were selected for their association with industrial users that may contribute high levels of PFAS to the municipal wastewater treatment plants
As part of the Stormwater Pollution Prevention Plan for the draft Industrial Stormwater general permit the Department is requiring a permittee to identify potential sources of certain per- and polyfluoroalkyl substances (PFAS) which could be exposed to stormwater and list and address these sources. The permit states that the PFAS compounds of interest are those addressed in EPA methods 533 and 537.1. Potential sources could include areas where fire retardants were discharged or stored, or where PFAS containing material used in the production process is stored or disposed of or may be accidentally spilled.
The Department is initiating an Industrial Wastewater Treatment Plant PFAS screening process through the use of an online survey to identify Treatment Plants that may have the potential to discharge PFASs. The Department recently piloted a survey designed to better understand possible PFAS sources with seven Industrial Wastewater Treatment Plants that ranged from small single operator facilities to large multi employee facilities. The feedback received from this pilot was used to refine the survey questions and make the process more efficient and effective. An electronic survey will be sent to 1,717 Industrial Wastewater Treatment facilities. The survey contains questions that explore the current and past industrial activities at the site. It also has the permittee examine, catalog, and submit to the Department all the chemicals used in their operations that could possibly contain PFAS. The results of the survey will be used to identify potential sources and type of PFAS as well as potential locations of environmental and public health risk.
MDE’s goal is to better understand where actions, including regulatory actions, are needed to reduce unacceptable human health risk and continuing releases of these materials into the environment and to take action to address these risks and releases.
PFAS Fact Sheet
PFAS Science Roundtable
MDE Water Supply Program PFAS information
St. Mary’s River PFAS pilot study
Information on the U.S. Environmental Protection Agency’s Action Plan for PFAS:
PFAS Action Plan: Program Update February 2020
Information on PFAS and human health is available at: