For around a century, heavy metals from one of the world's top lead and zinc mining regions pummeled the Spring River.
By the mid-20th century, the wildlife had taken a beating in this waterway that flows from the Missouri Ozarks into Kansas and down to Oklahoma’s Grand Lake, a popular vacation spot.
“The fish community was greatly reduced,” said James Whitney, a biology professor at Pittsburg State University in Kansas. “There was basically no mussels at all.”
Losses like that batter the food web.
Mussel beds, for example, feed river otters, raccoons, muskrats and turtles. They create underwater habitats like coral reefs. Algae grow there, insect larvae graze and hunt. Small fish and snails find refuge.
Then, in the 1970s and 1980s, a series of landmark federal environmental laws opened a path toward the river’s gradual recovery. Today, rare fish dart past rare mussels, a testament to the impact.
Similar stories played out in other waterways nationwide as the laws kicked off cleanups of industrial contamination and slapped regulations on factory outflows and city sewage. These changes, sometimes paired with habitat restoration and species reintroductions, helped animals bounce back.
Some waterways improved, and sportfish, aquatic insects or other animals returned. The Illinois River in Illinois, the Trinity River in Texas and the West Fork White River in Indiana all showed signs of progress.
In the nation’s third-largest city, the Chicago River and waterways linked to it saw a drop in certain factory chemicals, fecal bacteria, ammonia and other harmful substances.
Pollution does continue to be a problem, but the change from past decades is evident, said Austin Happel, a research biologist at Chicago’s Shedd Aquarium.
“There’s all these (fish) species that have come back,” he said.
Happel is one of the scientists who dug into decades of water sampling and fish data to uncover the transformation.
“At a survey at one site in the ‘80s they might have found three species,” he said, “but now at that same site, doing the same survey 30 years later, they find 15 or 20 species.”
Chicagoans fish in the river, and some take home their catch to eat. Last year the city held its first Chicago River swim in a century, drawing hundreds of participants.
“If you boil down the Clean Water Act, the idea is to have waterways that are fishable and swimmable for the enjoyment of Americans,” Happel said. “In Chicago, for sure, people are interested in both of those things.”
Pollution and progress in the Spring River
Mining at the junction of Missouri, Kansas and Oklahoma began in the mid-1800s. The area, known as the Tri-State Mining District, held a wealth of lead and zinc.
The mining fizzled out by the 1970s, but left behind millions of cubic yards of waste and abandoned mine shafts that leaked acid drainage and toxic metals into waterways when it rained.
Around the same time, Americans had grown frustrated with pollution. Rivers were dangerously dirty, billions of fish had died in the Great Lakes, Ohio’s Cuyahoga River had caught fire a dozen times, and pesticide poisoning had caused the bald eagle to nearly disappear from the contiguous U.S. Concern mounted that the country was under-regulating factories, strip mines and other sources of toxicity.
Congress passed a raft of bipartisan laws to shield communities, habitats and drinking water supplies and to protect species trending toward extinction.
These included the 1972 Clean Water Act, the 1973 Endangered Species Act, the 1977 Surface Mining Control and Reclamation Act and the 1980 Superfund law for major environmental cleanups.
The areas targeted for work included the Tri-State Mining District, parts of which were added to the nation’s list of Superfund sites in the 1980s.
“That all really gets into gear in the ‘80s and ‘90s – trying to clean up these areas,” Whitney said, “cover up some of these chat piles (mining waste) or bury them. Plug up mine shafts.”
The cleanups across the Tri-State Mining District are far from done, but thousands of acres have been improved.
For example, the U.S. Environmental Protection Agency and parties potentially liable for the contamination have remediated 14 miles of streams, 25 million cubic yards of mining waste and more than 3,000 properties in Jasper County in southwest Missouri.
The Spring River still has a problem with heavy metals, but the levels have dropped enough for scientists to see the signs of success.
In recent years, Pittsburg State University researchers have found promising numbers of Neosho madtom — a finger-sized catfish on the federal threatened species list.
Other riffle fish are also rebounding. Riffle fish are species that occupy shallow, fast-moving waters. Pollution tends to hit them hard. The Spring River has become more liveable for them again — and for the insect larvae they eat.
Mussels are coming back, too. Pittsburg State scientists have found six species living at a spot where none were found in 1985.
In 2024, scientists found the first live Neosho mucket (an endangered mussel) and Ouachita kidneyshell (considered threatened in Kansas) in part of the river that used to take in a lot of mining-related lead.
These animals may not be at the forefront of people’s minds, said Pittsburg State graduate Jamie Leeper, who helped survey for mussels in the river. But he said having diverse populations of mussels matters.
“They’ve all got their niche and they’ve got their role,” he said. “Whether or not they’re there affects other organisms that you might actually care about.”
Superfund cleanups are also helping animal populations recover in mining-polluted rivers in Colorado, Montana, California and Idaho.
Doing better isn’t the same as doing great
Scott Black, executive director of the Xerces Society for Invertebrate Conservation, is grateful that the Clean Water Act, Superfund law and mining reform have benefited U.S. drinking water supplies and river habitat.
“Rivers were on fire,” the ecologist said. “Many of them you could not swim in.”
But he said the progress since those dark days hasn’t occurred across the board, and it comes with significant caveats.
“We’ve improved,” Black said, “but we haven’t gotten to where we really should be.”
For example, the Clean Water Act does not regulate chemical use on farmland.
“Things like phosphorus and nitrogen that really mess up rivers,” he said, “As well as pesticides, including insecticides that kill insects.”
These substances fuel toxic algae blooms across the country. They cost water utilities in cities like Des Moines, Iowa, millions of dollars for treatment, and they ultimately drain from the Midwest down into the Gulf of Mexico, causing a Dead Zone off the coast of Louisiana where fish and other animals can’t survive.
Meanwhile, Black notes, scientists at the University of Tennessee and University of Washington found that even with federal laws on pollution and mining, streams in coal mining areas continue to have far fewer fish, invertebrates (animals without backbones, like insects and mussels) and salamanders than other streams.
More broadly, scientists found in a 2022 study that only about one-third of stream sites across the U.S. were in good condition, based on their populations of fish and of bottom-dwelling invertebrates.
Aquatic insects are vital to our landscapes, just like the pollinators that Americans show growing interest in supporting, Black said. Only, they don’t enjoy the same popularity.
The freshwater mussels native to U.S. rivers filter the water. When rivers are cleaner, Black said, water utilities don’t have to spend as much on treatment.
In addition to the inadequacies that Black sees in existing anti-pollution legislation, he sees a risk that enforcement of these laws, plus other federal environmental work, could backslide.
“My worry is there’s just less staff across the board,” he said, “All the agencies charged with some form of conservation are losing staff.”
Monthly reports from the U.S. Office of Personnel Management show that since Trump took office in January 2025, the EPA and the Natural Resources Conservation Service have each lost about one-quarter of their employees. The Fish and Wildlife Service has lost nearly one-third and the Forest Service more than one-tenth.
The Trump administration is also pushing to increase coal mining and keep coal plants going instead of transitioning to cleaner alternatives.
In an email to Harvest Public Media, the EPA Press Office said the agency remains dedicated to enforcing the Clean Water Act, which it does together with states. It said the EPA has the workforce in place for this, and the EPA has hit its highest civil enforcement numbers in years.
“Over the past year, EPA has undertaken a strategic restructuring,” the email said, “to better provide clean air, land, and water for all Americans grounded in an unwavering commitment to gold-standard science.”
It also said that Superfund efforts remain one of the agency’s top priorities.
“The Trump EPA is laser-focused on accelerating this work,” the email said, “to deliver health and economic benefits to communities faster than ever.”
Rivers face new challenges
Even though some rivers have improved under federal anti-pollution laws, they face an onslaught of ever-changing threats.
These come from modern pollutants, such as microplastics and forever chemicals. They also come from climate change.
Chicago has invested heavily in preventing its sewer system from overflowing into the river during storms. But global warming is now bringing storms that rain so hard, so fast that sewage overflows sometimes can’t be stopped.
In the Ozarks, the Spring River’s story has developed a new wrinkle, too.
In a stretch of the river that had always been relatively clean because it was upstream from most of the mining pollution, a Kansas Department of Wildlife and Parks worker found that one mussel bed appeared to collapse between 2014 and 2020.
Pittsburg State scientists then found the issue wasn’t isolated to that bed. Mussel densities in this historically cleaner part of the river had dropped significantly in recent decades.
They found that this stretch of the river is experiencing spikes of ammonia after storms and that poultry farms have proliferated in the area. Feces and litter on poultry farms can be a source of ammonia runoff. However, confirming whether this is the cause of the mussel decline would take further research.
To Whitney, it says a lot that mussels are now struggling with a new problem upstream while they recover from mining pollution downstream.
“It just shows how complicated conservation and ecology can be in a river system and how quickly things can change,” he said. “ There’s always new threats coming about.”
Celia Llopis-Jepsen is an environment reporter for Harvest Public Media and host of the environmental podcast Up From Dust. You can follow her on Bluesky or email her at celia (at) kcur (dot) org.
Harvest Public Media is a collaboration of public media newsrooms in the Midwest and Great Plains. It reports on food systems, agriculture and rural issues.
