Opinion: Rock Creek E. coli levels are dangerously high. Where are the public health warnings?

by Marlene Berlin

One day in late January, I went for a hike in Rock Creek Park. I emerged alarmed by what I had learned there about E. coli levels in the creek, and by the dearth of public warnings about its health hazards.

While hiking on Black Horse Trail. I saw two water technicians from the U.S. Geological Survey (USGS) taking samples from Rock Creek at the Joyce Road bridge. USGS regularly samples and analyzes the temperature, turbidity (sediment), and organic and inorganic chemicals and elements at this location. I asked one of the techs, David Brower, how the water looked.

“I can’t make qualitative statements about the water,” he replied. I thought a bit, then asked, “What is the level of E. coli in the water?”

“It is very, very high,” he said.

Brower went on to explain that the water has to be diluted by a factor of 1,000, or the readings would be off the charts. And he stressed that these E. coli levels pose a hazard to human and dog health. He told me that I should warn people not to come into contact with the water. Brower told me he often sees people and their dogs doing so, and it worries him.

I continued my walk, sobered by the conversation and wondering why there were no warning signs posted along the water where I often see adults, children and dogs playing around.

Back at home, I sought more data about E. coli levels from USGS, and answers about signage from the National Park Service and the DC Department of Energy and the Environment (DOEE).

USGS sent EPA links to reports it had conducted for DOEE in 2020. Then, too, it found high bacteria levels in Rock Creek as well as Soapstone, Broad Branch, Melvin Hazen and other Rock Creek tributaries. Its term for the water conditions is “impaired.”

As for warning signage, Rock Creek NPS first forwarded my question to Rock Creek Conservancy, which sent me an example of a sign the organization has placed in some locations:

Compare this to the warning signage posted by Montgomery County.

I sent the Maryland sign to Rock Creek NPS and DOEE. Rock Creek Park Superintendent Julia Washburn sent me a statement about the Park Service’s stream monitoring and restoration partnerships with Rock Creek Conservancy and DOEE. “We have used signs, social media, and web content to warn against wading, swimming, and pets in the streams. As we improve signage in the park, we will continue to make the public aware of unsanitary water quality,” the statement said.

And from DC’s environmental agency, I got this response: “DOEE is exploring options with our sister agencies to develop and install signage warning the public of this ongoing risk.”

DOEE has been monitoring E. coli levels in the District’s streams and rivers for some time. The agency conducts weekly testing with the aid of volunteers.

Because “[b]acteria levels in Rock Creek are frequently higher than water quality standards and pose a risk to the health of people and pets,” the District bans swimming and wading in Rock Creek and other DC waterways, DOEE said in its statement.

“However, many residents and visitors (as well as their pets) are unaware of this risk and do recreate in Rock Creek waters.”

Where is the E. coli coming from? DOEE’s Jeff Seltzer told me that the agency and partners are conducting several studies in an effort to identify the sources. Those include:

· In partnership with EPA and Virginia Tech, identifying human and non-human (i.e., dog, deer, and bird) sources of bacteria using new molecular techniques known as microbial source tracking in the Anacostia and Rock Creek watersheds. Results show that humans and wildlife are both substantial sources and bacteria pollution from these sources increased dramatically after rainfall.

· In partnership with USGS measuring stormwater runoff and bacteria near Luzon Branch in Rock Creek.

· In another partnership with Virginia Tech conducting studies of human bacteria pollution in the Anacostia River and its tributaries using different molecular techniques to those previously mentioned.

· In another USGS study using in-situ methods to directly measure bacteria in the Anacostia River. The measuring device is placed into the river, and it can report a result in 6 hours (to measure bacteria in a laboratory takes about 18-24 hours). This rapid measurement approach can inform source tracking in the Anacostia River and other rivers like the Potomac and Rock Creek.

“Getting a better understanding of bacteria sources and quantifying those sources using different tools and techniques will help inform management practices to control and mitigate bacteria pollution in District waters,” Seltzer wrote.

In the meantime, DOEE and NPS should work with haste to get warning signage up. The public’s health is at stake.