Summary

Description

The TriState Mining District, comprising portions of Jasper and Newton Counties, Missouri; Cherokee County, Kansas; and Ottawa County, Oklahoma, was mined intensively for zinc and lead for more than 100 yr. Wastes from historic mining, smelting, and related activities have contaminated surface and ground waters. The TriState District is drained by the SpringNeosho River system, which supports populations of the Neosho madtom Noturus placidus, a federally listed threatened fish species Williams et al. 1989; Wenke and Eberle 1991. This study was designed and implemented to determine the toxicity of porewater collected in potentially suitable N. placidus habitat in the Spring River system affected by mining. Porewater was collected from sites in the Spring River and its tributaries to assess toxicity to standard test organisms. Porewater toxicity testing provides a means for assessing sediment quality. A field study was conducted in September, 1995 to determine the toxicity of porewater and sediments in the Spring River and two tributaries. Sites were also sampled in an effort to better characterize the Neosho madtom habitat preferences, and benthic macroinvertebrate samples were collected and analyzed to determine associations between these organisms and N. placidus abundance and distribution. Samples of surface and interstitial pore waters were collected and analyzed for a suite of water quality parameters and for miningderived metals, and to be used in toxicity tests. The physical characteristics of the sites were also quantified. Biological sampling revealed that, consistent with previous studies, Neosho madtoms were generally most abundant on gravel bars containing proportionally greater amounts of fine material and lesser amounts of coarse gravel and stones. In the Spring River, this study confirmed the extension of the known range of the species from the confluence of Willow Creek, in Baxter Springs, Cherokee County, Kansas, upstream to Waco, Jasper County, Missouri Wilkinson et al. 1996. It may also occur as far upstream in Jasper County as the confluence of the Spring River mainstem and its North Fork but our sampling did not find any N. placidus at those locations. Lengthfrequency distributions indicated the presence of youngoftheyear at several Spring River sites, but the whereabouts of spawning sites and other aspects of the reproductive biology of the Spring River population remain unknown. N. placidus has not been found in any Spring River tributary sampled to date, nor has it been found in the Spring River downstream of Baxter Springs. A combination of physical, biological, and chemical factors may presently limit the distribution and abundance of the Neosho madtom in the Spring River. Among the latter, concentrations of zinc and other miningderived metals in the Spring River below Center Creek, and in both Shoal and Center Creeks may be sufficiently high to affect N. placidus.