EPA Region 7 Cleans Up Contaminated Tributary in Southeast Kansas
– EPA Region 7 Feature –
Strong commitment to ongoing cleanup of lead in Tri-State Mining District
By Luisa Garcia, Superfund and Emergency Management Division
Spanning nearly 2,500 square miles across Missouri, Kansas and Oklahoma, the Tri-State Mining District was one of the world's leading zinc and lead mining areas, producing over 400 million tons of crude ore between about 1850 and 1970. Over the past four decades, EPA has cleaned up millions of cubic yards of mining waste, chat piles, and contaminated soil caused by these and similar residual mine waste sites.
A recent remedial cleanup effort in Region 7 has made remarkable progress along a tributary of Tar Creek that flows within the Tri-State Mining District, effectively revitalizing, restoring, and returning nearly 185 acres for reuse.
Tri-State Mining District – A Dangerous History
Beginning in the 1850s, lead and zinc were heavily mined and processed from the three states. Raw ore was brought to the surface where it underwent the milling and smelting processes. During smelting, the desired metal is extracted from the rest of the rock by heating and melting. The remaining rock is not directly used so it becomes waste, but it still contains traces of the extracted metal.
Continuing until the last mine closed in 1970, these mining operations have left over 300 million tons of mining waste in the form of chat piles that have since contaminated the surrounding soil and water with heavy metals such as lead, cadmium and zinc, among others.
Since the 1980s, EPA has been investigating and remediating contaminated areas across the nation. Sites that are determined to pose substantial risk to human health and the environment are placed on the National Priorities List (NPL).
Four NPL Superfund sites currently comprise the Tri-State District, three of which are located within EPA Region 7: Cherokee County Superfund Site in Kansas, and the Newton County Mine Tailings and Oronogo-Duenweg Mining Belt sites in Missouri.
Cleanup at a Tar Creek Tributary
Within the Tri-State Mining District lies the Tar Creek Superfund Site in Ottawa County, Oklahoma, an adjacent site to the Cherokee County Site. The Tar Creek Site, however, is not solely the creek itself, but encompasses other contaminated land throughout Ottawa County including tributary streams.
The northwest tributary of Tar Creek is in the Cherokee County Site, and from past mining operations in the area, EPA had estimated that approximately 75 million cubic yards of mine and mill waste remained in this subsite alone. Before cleanup work around this Tar Creek tributary could begin, EPA staff and contractors and partnering agencies had to take special care to minimize further contamination and exposure risk.
According to Peyton Witham, an environmental specialist at the Kansas Department of Health and Environment, one of EPA’s support agencies for the Cherokee County Site, cleaning up this particular tributary of Tar Creek was important to ensure that the lower parts of the river basin were not recontaminated as the cleanup progresses in downstream areas.
“We want to reduce any possible exposure by encapsulating the hazardous material in a certain location and then controlling that in the future,” said Todd Campbell, EPA Region 7 remedial project manager. “The main objective of our mine waste cleanup activities in the Tri-State Mining District is the reduction of human exposure to lead, whether that be from direct bodily contact on one of the residual mine waste piles or from air dispersion/deposition or other transport mechanisms.”
When cleanup work started at the tributary, mine waste from the chat piles was transported to a repository where it was covered with 12 inches of clay and 6 inches of topsoil, resulting in an 18-inch clean cap and cover over the waste. This was followed by revegetation efforts to protect the cap from erosion and facilitate future reuse of the areas.
Reuse Opportunities Open Up
As a result of this remediation, Witham was pleased to report that reuse efforts have already begun within the Cherokee County Site.
“In residential areas, citizens can now safely use their yards, such as for planting a garden,” Witham said. “In more rural areas, property owners are using the land for agriculture and livestock.”
Wheat and soybean crops have already been produced, and in other areas, corn has been planted. Wetland grasses have also been growing to encourage a wildlife habitat, and fescue and clover have been planted for eventual livestock grazing.
Another portion of the Tar Creek cleanup focused on a small, intermittent stream that feeds into the creek. Portions of the stream with contamination had to be excavated and clean soil was brought in to fill those areas. This clean backfill was dug up from other parts of the site, which allowed for the creation of catch basins where runoff water can pond and deposit sediment throughout the tributary. These areas can now function as wildlife habitat, erosion controls, sediment traps, and water holes for livestock.
This cleanup around Tar Creek never could have happened without the dedicated partnership and permissions granted by Travis Parrish, the primary landowner of the contaminated areas. With expressed consent and collaboration with Parrish, EPA was able to access the land for sampling, testing and cleanup.
“The cleanup process went great and the land recovery goals were achieved. The ponds that were created are now also used for fishing,” Parrish said.
Cleanup efforts at this subsite in Cherokee County have removed over 1.1 million cubic yards of contaminated soil and mine waste over the past 20 years. The success at Tar Creek is just one of many examples of how small restoration efforts can have a big impact. The headwaters of Tar Creek begin in southeastern Kansas and flow south into Oklahoma and eventually into the Neosho River, which feeds into the Grand Lake O’ the Cherokees. Tar Creek and its tributaries are also part of the Neosho River watershed which, along with the Spring River watershed, make up the Grand Lake drainage basin.
The efforts made in this tributary directly contribute to the protection of human health and the environment throughout the entire watershed and the Tri-State Mining District.