With a tackle box and a fishing pole, Gary Sanders baits his hook with a worm and casts his line into the river outside of Desloge, Missouri.
“I caught a couple little bass,” he says. ”I think they were small mouth. They weren’t very big. They were only about that big -- only 6 inches long.”
Sanders is posted up at the Big River. He moved here from St. Louis a few years ago to live a more outdoors lifestyle. You won’t see him or many other fishermen in this area take home their catch for a fish fry though. That’s because these waters are still dealing with lingering contamination from lead mining.
For 200 years, millions of tons of lead were mined from a region in southeast Missouri called the Old Lead Belt. During the mining, heavy metals seeped into the waterways that flowed through the region and out to the Mississippi River.
“Big River is kind of the main stream that drains the Old Lead Belt, so it’s received a lot of contamination from historic mining operations and milling operations,” says Dave Mosby, an environmental contaminant specialist with the U.S. Fish and Wildlife Service.
Indeed, the state Department of Health and Senior Services has hung up signs that warn visitors about eating the carp or sunfish here.
“Those are species of fish in the Big River that ingest a lot of sediment during their normal feeding process,” Mosby says. “As a result they develop a lot of lead in their tissues.”
Scientists periodically test the fish tissue, water and soil for lead. But these mines are inactive now, so where is this contamination coming from? Part of the answer lies a few miles upstream, near the rural town of Leadwood where piles of mining waste sit. The piles of tailings, which contain concentrations of heavy metals that miners were unable to separate, look like large hills of ground up gravel or sand.
In 1992 the Environmental Protection Agency listed this area as a superfund site because the land is contaminated with lead, which poses environmental and human health risks.
“There’s a series of mill dams that have been improved over the years to keep the lead tailings in their place, (but) it has not always been effective,” Mosby says. “People have used mine and mill waste as aggregate in sandboxes and driveways and all kinds of ways.”
So when it rains, the contaminated acreage erodes and trickles into the tributaries that feed the Big River. Government agencies and mining companies like Doe Run have remediated a lot of these piles in the region, but many still feed increments of lead into the Big River.
Mosby estimates there is about 90 miles of contaminated sediment in the river. Ultimately, he wants to return the river to its pre-mining health. The key is removing that contaminated sediment from the river. The best place to do that? At low water crossing areas where fishermen can walk across the river over what looks like a small, shallow waterfall.
“This low water crossing causes the river to slow down upstream and a lot of the sediment drops out so it just naturally accumulates here,” Mosby says about a particular low crossing in Leadwood.
Mosby says that’s ideal because the contaminated sediment can be removed in these locations without significantly disturbing the flow or balance of the river. He says it’s a much more effective strategy than dredging willy nilly.
“Another idea is to actually design structures that serve the same purpose,” he says. “Sediment deposits behind them, you could go in occasionally after each high flow event, remove sediment without causing disruption behind there.”
Mosby says state and federal agencies are doing feasibility studies on these ideas, but that they are still a few years away for implementation. And complete cleanup of the river could likely be decades away.