By Reid Frazier, Julie Grant and Kara Holsopple | The Allegheny Front
The Monongahela River is a 130-mile waterway that begins in the mountains of West Virginia and ends in Pittsburgh, where its waters flow into the Ohio River. Over the course of that journey, the river winds through some of the most heavily industrialized lands in American history.
Though heavy industry has ebbed along its banks in recent years, the Mon still bears the scars of the region’s heritage as America’s workbench. So how polluted is the Mon? And what pollutants does its water carry?
LISTEN to the conversation between Kara, Reid and Julie
Clean or Dirty?
When it meets the Allegheny to form the Ohio River in Downtown Pittsburgh, the Mon is often brownish-looking while the other rivers are green to blue. Does that mean the Monongahela is dirtier than the others? Why is the Monongahela so brown?
The color of the Monongahela actually has nothing to do with how dirty or how clean it is. Paul Ziemkiewicz, former director of the West Virginia University Water Research Institute, said the color derives from the river’s unique geology. The Monongahela River is one of two large rivers in North America that flows north. (The other is the Mackenzie in northern Canada.)
“The Allegheny and much of the Ohio flow south, which means they were subject to glacial influence,” said Ziemkiewicz. “So they have an entirely different sort of bed geology. They’re gravel beds on the bottom, whereas the Monongahela is almost entirely shale sandstone.”
The glaciers that occupied North America during the last Ice Age stopped somewhere in Western Pennsylvania, depositing lots of stone and dirt. That’s in the Allegheny River, but not the Mon, which is basically mud on the bottom.
What’s in the Mon?
The legacy of coal mining in the region remains the Mon’s biggest pollution problem, according to experts. Before modern environmental laws, underground mines were constructed so that polluted water inside them flowed out and drained into nearby rivers and streams. And there were a lot of coal mines in the region, especially the Mon Watershed, for over 200 years.
Ziemkiewicz said that by the early ’70s, acid mine drainage, mostly from abandoned mines, was severely impacting the Mon. “That meant a lot of metals were getting into the river. The pH was depressed. And there was essentially no fish life,” he said.
The Mon was essentially a dead river in the early 1970s, but that situation began to improve around then because of modern environmental laws.
In 2021, the University of Pittsburgh’s Water Collaboratory and Three Rivers Waterkeeper collected 100 samples from 25 locations in tributaries that feed Pittsburgh’s three rivers.
The scientists found ample evidence of coal mining’s thumbprint in the rivers, including consistently “concerning” concentrations of manganese in tributaries of the Mon, and elevated concentrations of iron.
They also found high concentrations of nutrients in tributaries that feed into the Monongahela, mostly nitrogen and phosphorus. While “nutrients” might sound good, if concentrations are too high, it can trigger algal blooms, and excessive algae growth leads to lower oxygen levels, acidic water, and sometimes the death of aquatic life. This has happened in Lake Erie and the Ohio River.
These nutrients are coming from a variety of sources. When it rains, rainwater mixes with untreated sewage and can overflow into the rivers in Pittsburgh and other places where there are combined sewage and stormwater systems.
Nutrients also come from septic tanks, landfills, waste disposal sites, construction, runoff from impervious surfaces like rooftops and parking lots, and also from industrial discharges.
The Collaboratory’s testing also found high concentrations of cadmium in the streams that drain into the Mon. They call this a pollutant from both past and current steel production.
This is worrisome, they say, because cadmium can have negative health effects, and the Mon is a drinking water source for about a million people.
There are other historical pollutants, such as PCBs (polychlorinated biphenyls), a class of chlorinated chemicals that were banned in the 1970s because of their toxicity. Before they were banned, they were produced for 50 years. They were used in a wide range of products and technologies. PCBs were useful in fireproofing and other technologies, such as electrical equipment.
PCBs are bioaccumulators – they persist in the food chain, and are still found in large enough quantities that there are fish consumption advisories for fish caught in the Mon and other rivers in the region.
Health of Pittsburgh’s rivers has improved, but still faces threats from pollution, report says
A history of spills and other disasters
The Mon also has seen its fair share of one-time pollution events, including the 2009 fish kill on Dunkard Creek, a Mon tributary along the Pennsylvania-West Virginia border. During this event, a massive die-off of fish, salamanders, and freshwater mussels occurred. Investigators believe that mine drainage, laced with fracking wastewater, triggered toxic algal blooms.
Bringing life back to Dunkard Creek, one mussel at a time
There was also the Ashland oil spill in 1988, about 20 miles upstream of Pittsburgh in Jefferson Hills. An estimated 1 million gallons of the oil were released into the Mon. According to news reports at the time, around 23,000 suburban Pittsburgh residents were without tap water for a week, as the river carried pollution past their water intakes.
Dan Bain, a professor in Geology and Environmental Science at Pitt, who is the deputy director of the Water Collaboratory, called this a ‘nightmare scenario.’
“All of these small water providers, these drinking water providers along Mon (had) to turn off the Mon water as the water to make into drinking water. If you don’t have a backup source, if there is something that fouls your primary source, the only option really is to shut down,” Bain said.
Bain also worries about the impact of shale gas development in the watershed and its impacts on water quality in the Mon. Shale gas, solid and liquid waste, and leachate from landfills that accept these wastes are high in salts and radioactive materials, posing a threat to water quality.
“It’s just one thing after another on the Mon,” he said. “And that sort of allows us to slip into the thinking that it’s expendable, that it is not something that needs to be fixed. It’s already dirty. So what’s the matter if it’s a little bit more dirty?”
The long recovery of the river
The Mon began to recover in the early 1970s, with the passage of the Clean Water Act and modern environmental and mining laws, like the Surface Mining Control and Reclamation Act, which increased regulations on coal mining and funded a national effort to clean up abandoned mines.
These efforts have funded projects to clean up abandoned mine drainage throughout the region, and the river now has a sizable fish population.
Ziemkiewicz said one of these areas is the Cheat River and Cheat Lake area in the upper Mon watershed in West Virginia, where there’s been lots of work done to clean up this mine drainage.
“If you ever drive over Cheat Lake in the summertime, you’ll see fishermen, water skiers, people recreating on the lake that just didn’t happen 15 years ago. The Cheat River itself is now a continuous fishery from the Monongahela River all the way up well above the mining areas,” Ziemkiewicz said. “The water is clean, you don’t have red rocks (from mine drainage) anymore, and people just like it a lot better.
Bain says the Water Collaboratory found that the manganese levels in groundwater that people use for drinking water are going down.
He says even with all the historic and current pollution, the Mon should be seen as an asset.
“It’s a river that has come back, but we can keep making it come back more. There’s potential here,” Bain said. “If we allow our imagination to fail us, it’s kind of a tragedy.”
Good Fishin’
On a recent afternoon along the Mon near Elizabeth, people were fishing off the banks. One older man, who didn’t want to give his name, said he remembered fishing for carp and catfish in the Mon in the ’60s and ’70s.
“And the river could catch on fire because there was so much oil on it,” he said. “You’d throw out your line. At the end of the day, there’d be all grease on your line.”
He remembers that the river got cleaner for a while — but then the Ashland oil spill killed thousands of fish. He and a group of his friends lamented the loss of industry and jobs in the Mon Valley. But, they say, the fishing is better.
