Bioaccessibility of Arsenic and Lead in Iron King Mine Tailings and Dependence on Mineralogy and Speciation

The site of the now defunct Iron King mine has recently been added to the Superfund list by the US Environmental Protection Agency (EPA). This means that the area is known to possess a large degree of hazardous contamination and is of high priority to be cleaned up due to the proximity of human residents. The major contaminants at the site are arsenic and lead, both of which have been found in concerning amounts in atmospheric dust and soil of nearby neighborhoods. The toxicity of heavy metals and metalloids in soil or dust is largely dependent on their bioavailability. In this study, we determined the bioaccessibilities of arsenic and lead in several different tailings samples from the Iron King site. Tailings samples were taken from 12 different locations at the site in order to have sufficient mineralogical variation. The samples were extracted using simulated lung and gastric fluids in accordance with standard bioaccessibility testing procedures. The extracts were analyzed using inductively coupled plasma mass spectroscopy (ICP-MS). We plan to apply the results of this study to aid clean up and remediation efforts at the Iron King mine site as well as other Superfund sites.