DEP Examining Samples Of Suspect Clay From Marsh Creek Lake

CHESTER COUNTY, PA — The Department of Environmental Protection on Earth Day sent investigators to Marsh Creek Lake to collect samples of an unidentified substance reported on the banks of the lake.

A DEP spokesperson said the department has taken samples of gray muddy clay deposits showing up in Marsh Creek Lake near the site of a more than 8,000-gallon drilling fluid spill into the wetlands in August 2020. Sunoco's Mariner East 2 pipeline construction was halted after the accident, and an effort has been ongoing to reroute the pipeline around the state parklands. Read that report from August 2020 here.

Six weeks after the spill, a 33-acre portion of Marsh Creek Lake remains closed to recreational boating and fishing and all other public use because drilling fluids were on the lake bottom, said DEP in an administrative order issued in September. Read that story here.

DEP said an investigation of the substance that is showing up this spring on the banks of the lake is ongoing, as the samples collected last week are under analysis.

DEP Community Relations Coordinator Virginia Nurk said preliminary field tests for conductivity and pH taken Friday "did not yield any immediate conclusions on the unknown substance." She said DEP will run additional tests on the samples "in an effort to determine the exact nature of the material."

"We are not always able to look at a material and immediately definitively characterize it; we often rely on lab verification to ensure accuracy," said Nurk on Monday.

Residents in the area suspect the substance is bentonite from drilling fluid that escaped into the lake on Aug. 10 when Mariner East 2 crews had an "Inadvertent Return" (IR) from the Sunoco pipeline construction through the wetlands area. Residents said they alerted the Pennsylvania Department of Conservation and Natural Resources, and Pennsylvania Fish and Boat Commission.

Bentonite is an ingredient commonly used as a lubricant in drilling fluids; sometimes the mixture is called bentonite mud. It is a naturally occurring mineral substance, but its presence in large quantities can upset local ecosystems, experts say.

West Whiteland Residents for Pipeline Safety on April 23 posted on social media, "Yesterday a resident near Marsh Creek Lake alerted us to an unusual bentonite-like deposit on the shore beyond the end of Milford Road. Upon further investigation late yesterday afternoon, it was determined that it does indeed resemble bentonite and appears to be seeping up from underground. A stick inserted into the deposit easily slid down a few feet, and it was easy to reach into the ground and pull up handfuls of what appears to be bentonite/drilling mud."

Ginny Kerslake, a local activist who serves as an environmental watchdog over pipeline construction in Chester County, said she is waiting for DEP's report, though her background in science has convinced her that the emerging muddy substance is drilling mud released in the area during the August Inadvertent Return at the state park.

Nurk acknowledged that on April 22 "DEP was advised of the discovery of an unknown substance on the banks of Marsh Creek Lake by the PA Fish and Boat Commission (PFAB)." Nurk said "DEP coordinated with PFAB and DCNR, who both responded to the site on April 22 to observe and inspect the area. DEP collected samples this morning in an effort to identify the substance. This investigation is ongoing; more information will be shared once available."

It's been a busy month for DEP looking into pipeline construction issues around Chester County. Earlier in April, investigators looked into discolored watering entering Valley Creek near Chester County Library. Read that story here.

The Chester County District Attorney's Office last week filed a civil lawsuit against partner companies of the Mariner East 2 pipeline, calling the work in Chester County a "nuisance" to the health, safety, and welfare of the county. Read that full story here.