Toxic pollution continues to wash into the Anacostia River in the District of Columbia, adding to the longstanding contamination that already makes it unsafe for residents to swim or wade in some places or eat fish caught from its waters.

That’s the surprising finding of a new study commissioned by the District Department of Energy & Environment as it begins work on a plan to clean up toxic hot spots in the “forgotten river,” as the Potomac River tributary has been dubbed because of its severely degraded condition.

In a nearly 200-page report, Tetra Tech, the District’s consultant, provided new details on the high levels of toxic chemicals and metals already known to linger in the river’s sediment from historic and mostly industrial pollution sources.

But the report, released late last week, noted that sampling of river sediments also detected evidence in certain spots of ongoing pollution – a finding Wesley Rosenfeld, assistant DOEE general counsel, called “unanticipated.”

“Something is happening basically as we speak,” Rosenfeld said. “We can’t clean up the river without eliminating an ongoing source of contamination.”

Rosenfeld said particularly high levels of contaminants in some samples near outfalls and industrial sites indicate the pollution “isn’t just historical.”

Though the report calls for further investigation to confirm sources, it found high levels of contaminants near outfalls at the Washington Gas Light Company’s former coal-gasification plant and the Washington Navy Yard, located on either side of the 11th Street Bridge. The spike in contaminants was also found near the former Steuart Petroleum terminal just downstream of the South Capitol Street Bridge.

These locations are among about a dozen along the river that already are considered potential environmental cleanup sites based on their historical contamination of groundwater or river sediment, including a recently demolished Pepco plant on Benning Road and federal sites like the Bureau of Engraving and Printing.

Based on more than 900 samples collected and analyzed over two years, the Anacostia Sediment Remediation Investigation Report represents the most extensive analysis to date of the contaminants that have been leaching into the river for generations. Its findings form the foundation for the District’s cleanup plan, which will require parties responsible for the contamination to share in the cost of its cleanup.

The DOEE commissioned the study as part of its commitment to produce a final plan by mid-2018 for cleaning up contamination in a 9-mile stretch of the Anacostia. It is available for public comment until May 2.

“The District of Columbia and the public have known that the Anacostia River is degraded,” Rosenfeld said. “This report doesn’t tell us anything different. What it does tell us is where those contaminants are located and how they affect human health and the environment.”

It confirms, for instance, that the suite of toxins found in the river’s sediment and waters include known carcinogens that threaten the health of wildlife and of those who eat fish from the Anacostia. Advisories warning residents not to eat what they fish from the river already are in place, but a 2013 study found that many of them still do.

The report details how the sediments of this tidal river still bear the scars of an urban and industrial past, one advocates say won’t go away without a costly cleanup. Among the options to be considered for dealing with the toxic sediments: dredging and removing them, or capping them in place with a clay layer to prevent them from being picked up by the organisms that fish eat or from being stirred back into the water.

Representatives from organizations expected to submit comments on the report said they were still wading through its findings this week.

“While there is always more data that could be collected, we now need to shift our attention to developing the plan to clean up these legacy pollutants,” Jim Foster, president of the Anacostia Watershed Society, stated in a press release.

The report lists several of the sites as potential sources of polynuclear aromatic hydrocarbons (PAHs), compounds associated with incomplete burning of fossil fuels or other organic materials, and polychlorinated biphenyls (PCBs), now-banned chemicals once widely used as coolants or insulators in electrical equipment.  Both groups of chemicals are associated with cancer.

Pesticides were also found throughout the river samples as well as toxins, such as lead and mercury that can cause problems with the immune and nervous systems of living organisms.

Beleaguered organisms

Researchers analyzed hundreds of samples from the river’s first 6 inches of sediment, subsurface sediment (up to 10 feet below the river bottom surface) and water, as well as fish tissue and the small organisms that fish eat.

Those benthic organisms that live in or on the bottom sediments are often the first to show signs of contamination, which then travels up the food chain as other animals eat them. In this study, 75 percent of the benthic organisms sampled demonstrated some form of toxicity from being exposed to the sediment.

“That means they either had shorter lives or poorer overall health” when compared with a control group, said Rosenfeld.

Those poor health trends continued as they traveled up the food chain. Fish tissue showed the presence of PCBs and heavy metals throughout the study area, with higher levels in some reaches like the Washington Channel.

The report’s findings bolster warnings that anglers should limit their consumption of  locally caught fish, especially bottom-feeders from some portions of the river, and that people should not swim in the river — though the District would like to remove both of those warnings by 2032.

“Addressing the legacy pollution is one of the last major hurdles in making the Anacostia River fishable and swimmable by 2025,” Foster said, citing an earlier goal that his organization has set. “It’s time to get it done.”