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Maryland Department of the Environment

MDE issues report on sampling of Md. public drinking water systems for PFAS


Water systems serving about 70% of Maryland’s population sampled; samples from two systems exceed federal health advisory level; report describes steps taken to protect public health

BALTIMORE (July 1, 2021) – A new report provides a detailed look at levels of a class of chemical compounds known as PFAS (per- and polyfluoroalkyl substances) in public drinking water systems across Maryland.

The report, prepared by the Maryland Department of the Environment (MDE), describes the results of sampling of nearly 130 drinking water treatment plants serving about 4.3 million people, or about 70% of Maryland’s population. Samples from two water systems showed levels greater than the U.S. Environmental Protection Agency’s health advisory level for those compounds. The report describes actions taken in response by MDE and others to protect public health.

“Maryland is committed to reducing the risks of PFAS chemicals in our state and continuing our close coordination with scientific, local, state and federal partners,” said Maryland Environment Secretary Ben Grumbles. “Our report on PFAS in public water systems serving the majority of Marylanders is a big step forward in understanding, communicating, and reducing the potential for harm.”

PFAS refers to a 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 have led to PFAS entering the environment, where they have been measured by several states in soil, surface water, groundwater and seafood. 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 — PFOA and PFOS — may lead to adverse health effects in humans.

The risk posed by exposure to PFAS is an emerging and evolving national concern. MDE has initiated a multi-pronged, risk-based, scientific approach to understand, manage and communicate the risks associated with PFAS exposure. An integral part of this is a better understanding of the occurrence of PFAS in public drinking water supplies. After working to identify locations with the highest potential relative risk of PFAS occurrence, in September 2020, MDE initiated the first phase of public water system sampling.

Currently, there are no federal regulatory drinking water standards for PFAS. However, the Environmental Protection Agency (EPA) has issued a health advisory level of 70 parts per trillion (ppt) for the sum of the concentrations of PFOA and PFOS in drinking water. EPA has stated that its health advisory level for PFOA and PFOS offers a margin of protection for all Americans throughout their life from adverse health effects resulting from exposure to PFOA and PFOS in drinking water.

MDE’s new report, “Understanding the occurrence of Per- and polyfluoroalkyl substances (PFAS) in Maryland’s Public Drinking Water Sources – Phase 1,” includes results of sampling of finished water from 129 drinking water system treatment plants. The 129 treatment plants monitored under Phase 1 were selected for priority sampling based on MDE’s evaluation of the potential relative risk for PFAS exposure through drinking water. The sampling showed quantifiable levels of PFOA and PFOS, the two most studied PFAS compounds, in 98 samples. Two samples measured PFOA and PFOS greater than the EPA health advisory level of 70 ppt. Two others measured the compounds between 35 ppt and 70 ppt and 23 samples had PFOA and PFOS levels between 10 ppt and 35 ppt.

The highest measured levels of PFOA and PFOS were found in samples collected from individual treatment plants serving a portion of customers for 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.

Given that 75% of the samples tested under Phase 1 detected quantifiable levels of PFAS, MDE is continuing monitoring efforts of PFAS in public drinking water treatment systems and has moved on to sample an additional 62 systems in phase II of this effort. Sampling for the second phase of this study was conducted between March and May 2021. MDE will address any unacceptable risks and produce a report on these results as well. In addition to the Department’s commitment to understanding PFAS in drinking water, MDE plans to assess PFAS levels in seafood (in recreationally caught fish), wastewater and other potential sources such as sewage sludge. Information on Maryland and PFAS, including the new report, is available on MDE’s website.

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