News Release

Historical Mining Continues to Degrade Sediment Quality in Empire Lake

It has been more than 30 years since the lead and zinc mining ended in the Tri-State Mining District in southeast Kansas, southwest Missouri, and northeast Oklahoma.  However, past mining activity has contaminated the sediment in Empire Lake with cadmium, lead, and zinc concentrations much greater than background concentrations and much greater than probable effects levels for toxic biological effects.  Empire Lake, completed in 1905, is an impoundment on the Spring River in Cherokee County, Kansas, near Galena.

Overall, cadmium, lead, and zinc concentrations in the bottom sediment of Empire Lake have decreased over time following the end of lead and zinc mining in the area.  However, the concentrations in the most recently deposited bottom sediment continue to exceed the probable-effects guideline by 440-640% for cadmium, 40-80% for lead, and 580-970% for zinc.  Probable-effects guidelines are 4.98 parts per million (ppm) for cadmium, 128 ppm for lead, and 459 ppm for zinc.  During high inflow periods, Empire Lake bottom sediment can be resuspended and the lake may become a source of contaminated sediment.  Contaminated sediment that passes through or originates from Empire Lake will be deposited in downstream environments possibly as far as Grand Lake in Oklahoma.

The results are from a two-year study done by the U.S. Geological Survey, in cooperation with the U.S. Fish and Wildlife Service and Kansas Department of Health and Environment. The study provides information needed to support efforts to restore the ecological health of Empire Lake.  Results from Phase I of this study showed that concentrations of lead in Spring River bed sediment increased 7 times during it’s 22-mile course through Kansas.  "The study has shown that, even though major mining activity upstream of Empire Lake had ended by about 1920, the sediment delivered to the lake today is still greatly contaminated with cadmium, lead, and zinc,” said Kyle Juracek, project chief.  “The mining-related contamination is a long-term problem.”

John Miesner, U.S. Fish and Wildlife Service, stated that, "The data contained in this report is important for us to better understand the extent and significance of the contaminated sediments stored in Empire Lake. This information, along with the earlier publication of Spring River sediment data, will help us understand the volume of mining waste that has been transported into the aquatic environment and the adverse impacts that likely occur to the aquatic environment.  This data, along with other studies being conducted on the Spring River watershed, will help provide us with the information necessary to develop plans to improve the Spring River from the impacts caused by mining.”

The new Empire Lake sediment quality report for Cherokee County is now available online at:

http://pubs.water.usgs.gov/sir2006-5307/

Printed copies of Scientific Investigations Report 2006-5307, “Sedimentation and Occurrence and Trends of Selected Chemical Constituents in Bottom Sediment, Empire Lake, Cherokee County, Kansas, 1905-2005,” by Kyle E. Juracek, will be available in February and may be purchased from the USGS Information Services, Box 25286, Federal Center, Denver, Colo. 80225, or call 1-888-ASK-USGS. A limited number of copies will also be available from the USGS office in Lawrence, Kansas.

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