HEAVY METAL ASSOCIATIONS WITH MINERALOGY AND GRAIN SIZE AT THE TAR CREEK SUPERFUND SITE, PICHER, OK

The Tar Creek Superfund site is located in Picher, OK in the historic Tri-State Mining district of Missouri, Kansas and Oklahoma. Mine waste (chat) is found in piles up to 60 meters high throughout Picher and the surrounding area. Chat piles contain elevated levels of heavy metals (Pb, Zn, Cd) present in both detrital ore and secondary mineral phases. Wind erosion, run-off, and direct contact with chat are exposure pathways often linked with a high incidence of elevated blood Pb levels and learning disabilities in local children. The goal of this work is to determine a geochemical fingerprint for detrital (primary and secondary minerals) grains associated with lead and to spatially map their contribution to lead transport in Tar Creek. Pile runoff and acid mine drainage, coupled with geochemical transformations during transport, deliver a flux of dissolved and particulate metals to Tar Creek, which flows through downstream communities and into Grand Lake o’ the Cherokees. To quantify the mass transport of heavy metals associated with detrital minerals, samples from a range of depositional settings are sized-fractionated, analyzed for bulk and trace element chemistry by X-Ray Fluorescence and for modal abundance of mineral phases by X-Ray Diffraction. Preliminary results suggest that metal concentrations as a function of grain size after transport no longer reflect the exponential concentration increase with grain size decrease relationship seen in in-situ chat.