PFAS—Information on the Maryland Department of the Environment’s Efforts to Address PFAS in Maryland’s Drinking Water Sources

Per- and polyfluoroalkyl substances (PFAS) are a group of man-made chemicals that include PFOA, PFOS, GenX, and many other chemicals. PFAS have been manufactured and used in a variety of industries around the globe, including in the United States since the 1940s. These chemicals are persistent in the environment and the human body, meaning they do not break down easily and can accumulate over time. People may be exposed to PFOS and PFOA from the air, indoor dust, water, food and numerous consumer products. According to Center for Disease Control (CDC) the potential for health effects from PFAS in humans is not well understood. PFOS, PFOA, PFHxS and PFNA have generally been studied more extensively than other PFAS. In general, animal studies have found that animals exposed to PFAS at high levels resulted in changes in the function of the liver, thyroid, pancreas and hormone levels. According to the Agency for Toxic and Disease Registry (ATSDR) some, but not all, studies in humans with PFAS exposure have shown that certain PFAS may:

  • affect growth, learning, and behavior of infants and older children
  • lower a woman’s chance of getting pregnant
  • interfere with the body’s natural hormones
  • increase cholesterol levels
  • affect the immune system
  • increase the risk of cancer

Scientists are still learning about the health effects of exposures to mixtures of PFAS. Because animals and humans process these chemicals differently, more research is needed to fully understand how PFAS affect human health.

PFAS can now be found in living organisms, including fish, animals and humans, where PFAS can accumulate and persist over time. PFOA and PFOS, two of the most widely studied PFAS, have been detected in the blood serum of up to 99% of samples collected between 1999 and 2012 in a population that is representative for the U.S.

In 2016, the United States Environmental Protection Agency (EPA) established Health Advisory Levels at 70 parts per trillion (ppt) for two PFAS: Perfluorooctanoic Acid (PFOA) and Perfluorooctane Sulfonate (PFOS). Since then, States and Federal agencies have been working together to address the potential presence of PFAS in the nation’s drinking water sources. In February, 2019, EPA published their PFAS Action Plan. EPA has also published a fact sheet  summarizing key actions such as moving forward with the Maximum Contaminant Level (MCL) process, clean up strategies, monitoring, research and enforcement. Congress is presently considering a number of different legislative proposals aimed at addressing the challenges associated with PFAS such as establishing an MCL, funding sources for PFAS contamination assessments and cleanup, and the need for further research.

As part of the third Unregulated Contaminants Monitoring Report (UCMR3), forty-two water systems in Maryland were monitored for PFOA and PFOS between 2012 and 2015. As a result of this study, PFOA was detected in only one sample in Maryland (at Perryman in Harford County) at a level below the 2016 EPA Health Advisory of 70 ppt.

The Department of Defense (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. Since that time, PFAS compounds have been identified in at least four additional military installations. As additional testing proceeds there may be other DOD installations in Maryland where PFAS compounds are found in the groundwater.

MDE's goal is to establish a risk-based scientific approach to detect, evaluate and minimize the impact of PFAS in the State. MDE has initiated a project to develop a GIS-based map to identify potential sources of PFAS in Maryland and to prioritize water sources for PFAS sampling. This effort will include surveying other State and local agencies that may have knowledge regarding the use of PFAS in specific jurisdictions, such as fire training areas utilizing foams. As we continue our efforts, MDE will report key findings. Additionally, MDE has prepared and placed on its website a document  titled “Basic Information on PFAS." A memo was also sent to Community and Noncommunity, Nontransient public water systems; local environmental health departments, and the Maryland Department of Health providing information on the Maryland Department of the Environment’s efforts to address per- and polyfluoroalkyl substances (PFAS) in Maryland’s drinking water sources.

Linked Documents for Information on PFAS

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For more information, contact the Water Supply Program at 410-537-3702 or

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