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January 16, 2014 | 12:00 a.m. CST
Old carpet and rags hang from the side of the Goodwin Sinkhole in Laclede County. They wave in the air like flags marking a devastated site. Covered with dirt, a once-white stuffed bunny sits like a mascot at the entrance to the gravel road that zigzags down to the bottom of the sinkhole. A pile of worn-down tires that could take you through time sits at the top, showing the progress of the Missouri Caves and Karst Conservancy. But one look to the bottom shows there is still a lot to be done.
Experts say a sinkhole collapse shouldn’t worry people. Pollution should.
Sinkhole pollution is a bigger threat than sinkhole collapse, which — with its dramatic “earth-swallows-man” headlines — gets all of the attention. In reality, “only 15 percent of all sinkholes are collapsed in origin,” says Jon Beard, vice president of MCKC.
When a sinkhole opens up, people tend to dump their trash in it. Seems like basic human tomfoolery. The consequences of doing so in karst environments — landscapes with limestone foundations that have been eroded to create sinkholes, caves and the porous ground — is that everything thrown in a sinkhole might directly contaminate the water.
With 15,981 sinkholes, Missouri is geological Swiss cheese. For hundreds of years, these sinkholes have acted as dumps, filling up with trash to the point that no one can tell they were sinkholes to begin with. “You name it, we have found it,” says Klaus Leidenfrost, project manager for Goodwin Sinkhole and Cave Restoration.
“The thing we have to remember is whatever you put on the surface of the ground in a karst environment is going to go underground, sooner or later,” Beard says. Karst is like a sponge.
When you soak up dirty water, then rinse it out, some of the filth comes out with the water, and some stays in the sponge, and it infects the next batch of water. In the same way, the limestone and dolomite found all throughout the ground in mid-Missouri absorb the trash dumped by people unaware of its effect.
Many Columbians get their water from the Missouri River. But this does not mean it’s in the clear. Trash and pollutants that come through the karst land eventually flow into streams, which feed the river. Although the pollutant might be diluted after traveling such a far distance, the water comes from many feeder streams, and the amount of pollution can add up.
“What you put in the sinkhole we have to drink eventually,” says Bryan Mayhan, assistant director of MU’s Center for Applied Research and Environmental Systems.
Living with Sinkholes
Ken Horn has spent almost 25 years living on land dotted with sinkholes across the road from Rock Bridge State Park. Horn knew the property had sinkholes when he moved in. He was sure to build around the already depressed sinkholes and didn’t find pollution in them at the time. One sinkhole in particular, at the front of his house, fills up with water after rainstorms. His horses bathe and drink from it until the water drains out in the cave system, Horn says.
So much is still unknown about living on this type of land. In fact, there’s debate about whether animals should be allowed near sinkholes. Cattle in Taney County are to blame for polluting the Tumbling Creek cavesnail, Beard says. A cattle farm was set up over karst, and the grass was not given proper time to mature. That meant that when cattle died, toxins from their carcasses infiltrated the cave’s groundwater more easily.
“The health of the human race depends on the health of the caves and karst,” says Bonnie Heim, an MCKC director. This is why the group organizes sinkhole cleanups; it is trying to prevent pollution while preserving the cave system. The work is volunteer-based and requires a lot of funding. “Seeing people here gives me hope,” says Courtney Kulinski, a volunteer at the Goodwin Sinkhole cleanup. “It’s refreshing.”