The Tar Creek Superfund Site is a part of the abandoned lead and zinc mining region known as the Tri-State Mining District (Oklahoma, Kansas, and Missouri). Over 100 years of underground mining left behind nearly 180 million metric tons of contaminated mine waste, posing significant risks to human health. Despite 34 years of remediation efforts, the Tri-State Mining District is still one of the nation’s worst lead-contaminated sites. This study evaluated a variety of toxic metal concentrations in sediments across the floodplain of Tar Creek, a principal drainage stream for the Mining District. Four sediment profiles were evaluated along a transect across the floodplain in Miami, Oklahoma. Additional surface samples were obtained at six locations adjacent to the flood-prone creek. Sediment cores were acquired using a slide hammer and a steel corer lined with plastic tubing, which was pounded to a depth of 0.6 m below land surface. Core liners were cut open and samples were collected every 10.2 cm for metal analysis. Metals were extracted from the cores nearest the stream using USGS Method E011, in a mixture of hydrochloric, nitric, perchloric, and hydrofluoric acids. The extractants were analyzed for zinc, lead, cadmium, nickel, manganese, iron, arsenic, chromium and aluminum using Inductively Coupled Plasma-Atomic Emission Spectrometry (ICP-AES). Metal concentrations with depth varied by up to 64% in two profiles. Lead concentrations were highest in the profile nearest the creek, and ranged from 140 to 1611 mg/kg, which exceeded the EPA recommended threshold levels of 30.2 mg/kg. Arsenic, chromium, and nickel concentrations ranged from 20 to 140 mg/kg, which also exceed the EPA limits. These results were used to guide the selection of a second round of extractions for the samples obtained nearest to the stream. These additional samples will be incorporated in our ongoing analysis.

Evaluation of metal concentrations in near-stream sediments, Tri-state Mining District, Miami, OK

2019 Spring National Meeting

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