New Mexico Geological Society Annual Spring Meeting — Abstracts

Mining legacy has led to concentrations of heavy metals such as lead (Pb), arsenic (As), and uranium (U) above the EPA MCL’s in waters and soils on partner Native American lands. There is a pressing need for culturally responsive approaches to mitigate the toxic effects of mining legacy in the environment and human health. In this context, using native plants and root-associated fungi for heavy metal removal has been of interest for bioremediation applications. We aim to determine the removal of Pb and As using various root-associated fungi species isolated from a metal-contaminated site. Fusarium oxysporum species complex, Darksidea alpha, Edenia sp., Monosporascus sp.1 and Monosporascus sp. 2 were tested in liquid media batch reactors containing single (As or Pb) or mixed (As and Pb) metals at 4 mg/L. Aqueous analysis performed using inductively coupled plasma optical emission spectroscopy indicates that As had limited removal (<12.5%), and Pb had removal ranging from 56.2 – 91.8% in single Pb experiments, and 62.5% - 93.7% in As and Pb metal mixture experiments. Acid digestions and scanning electron microscopy indicate possible adsorption and sequestration of Pb in fungi cells. Biomass measurements indicate that average fungal biomass ranges from 3600 – 2000 mg/L in Pb, 2400 – 3900 mg/L in As, and 2000 – 4000 mg/L in As and Pb mixtures. Our results indicate that fungi can remove Pb, which is a cationic species, and As, an oxyanion, has limited removal by fungi due to electrostatic effects. These results using fungi native to metal-contaminated sites have implications for bioremediation.