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PFAS found in Montgomery County pond and stream, prompting health advisory

Great Seneca Highway and Key West Avenue
Testing finds elevated levels of PFAS in a stormwater pond and nearby stream near Great Seneca Highway and Key West Avenue in the Gaithersburg and Rockville area. (海角社区app/Mike Murillo)
Red, temporary fencing
Red, temporary fencing goes up around a contaminated pond in Montgomery County, Maryland. (海角社区app/Mike Murillo)
Pond across Great Seneca Highway
At the pond, across Great Seneca Highway near where Decoverly Drive crosses, crews are trying to keep people and pets out because of harmful chemicals found in the area. (海角社区app/Mike Murillo)
Montgomery County Executive Marc Elrich
County officials, including Montgomery County Executive Marc Elrich, address the pond’s harmful chemicals at a news conference. (海角社区app/Mike Murillo)
Signs about harmful chemicals
Signs at a news conference about harmful chemicals found in a Montgomery County pond. (海角社区app/Mike Murillo)
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Great Seneca Highway and Key West Avenue
Red, temporary fencing
Pond across Great Seneca Highway
Montgomery County Executive Marc Elrich
Signs about harmful chemicals

Red, temporary fencing went up around a contaminated pond in Montgomery County, Maryland, as leaders warn you to stay out of nearby waterways.

County officials say your tap water is safe, in a stormwater pond and nearby streams near Great Seneca Highway and Key West Avenue in the Gaithersburg and Rockville area.

map
Click to enlarge. (Courtesy Montgomery County/Department of Environmental Protection)

At the pond, across Great Seneca Highway near where Decoverly Drive crosses, crews are putting up the fencing to keep people and pets out.

The affected waterways run near Shady Grove Hospital along Great Seneca Highway and just past Muddy Branch Road.

PFAS are manmade chemicals often called 鈥渇orever chemicals鈥 because they do not break down and can build up over time in the environment and the body.

Jennifer Macedonia, director of the Montgomery County Department of Environmental Protection, said testing pointed to an area near a former county site, where firefighters trained for decades until 2015.

鈥淭he state’s testing detected high levels of PFAS in an area on and adjacent to the site of the county’s former public safety training facility,” Macedonia said.

Officials said the contamination may be tied to chemicals used in firefighting foam at that training facility.

The high readings came to light after WSSC Water requested more testing in the Muddy Branch area. WSSC Water PFAS Program Manager Laura O鈥橠onnell said despite the findings in the pond and stream, the drinking water in the area remains safe.

鈥淚 want our WSSC Water customers in Montgomery and Prince George’s counties to know that the water we provide is safe. This is not a public water supply issue,鈥 O鈥橠onnell said.

Montgomery County Executive Marc Elrich said the county is working to respond and protect the public.

鈥淭he county is taking this issue and the concern very seriously, and it’s taking steps to inform the public and protect public health and the environment,鈥 Elrich said.

The county filed a lawsuit in 2023 against companies that made PFAS, accusing them of hiding risks while profiting from the chemicals.

Elrich also noted the chemicals are widespread.

鈥淭his stuff is ubiquitous and it’s not always easy to figure out where it came from, but it’s there now,鈥 Elrich said.

Health officer Dr. Kisha Davis said the greatest risk comes from repeated exposure over time.

鈥淭he health risks are tied to chronic exposure, meaning drinking contaminated water or eating contaminated fish every day for years, which allows the chemical to gradually accumulate in the body’s tissues,鈥 Davis said.

She added that brief contact is less concerning.

鈥淚 don’t think that folks need to worry too much about if they were playing in that stream over the weekend,鈥 Davis said.

For nearby homeowners with private wells, the county said it鈥檚 reaching out directly and offering free testing to make sure their drinking water is not affected.

Out of caution, the county is advising residents to stay out of the affected waterways, keep pets away and avoid eating fish caught there.

Officials said additional testing is underway to determine how far the contamination may extend.

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Mike Murillo

Mike Murillo is a reporter and anchor at 海角社区app. Before joining 海角社区app in 2013, he worked in radio in Orlando, New York City and Philadelphia.

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