Larrea tridentata Uptake of Trace Metals in Mine Tailings within an Arid Region of Nevada, USA

Larrea tridentata (creosote bush) growing in contaminated tailings of the Techatticup Mine in Nelson, Nevada were sampled and analyzed for trace metals. Samples were also collected outside the mine tailings to measure geogenic trace metal levels. These data show that some trace metals (Cu, Pb, Zn, Co, Fe, Li) enter L. tridentata through root tissues, but at significantly lower levels than in the tailings area. Trace metals that enter the root are higher in concentration in the outer than in the inner root tissue, possibly due to L. tridentata blocking their absorption at the outer root surface. Data further show the plant’s ability to block the intake of these toxic trace metals that may adversely affect the plant. Statistical analysis suggests that certain metals, while not in high abundance, may be utilized by the plant for self-defense mechanisms or to aid in plant development. Finally, differences between plant components may be the result of hyper-accumulation of useful trace metals (e.g. B, Cr, Zn) and a blockage of potentially toxic trace metals (e.g. Cd, Pb, V).