Drs. Jon Chorover and Raina Maier, University of Arizona Superfund Basic Research Program (UA SBRP) received an NIEHS R01 grant to support an extensive project entitled: “Nano-scale Mechanisms of Metal(loid) Rhizostabilization in Desert Mine Tailings”. The purpose of this project is to identify multi-scale processes and links between biological structure and contaminant geochemistry during phytostabilization of mine tailings.
In arid and semi-arid areas of the world, including regions of the western United States and the northern region of Mexico, mine tailings and their associated metal contaminants, such as arsenic, lead, and cadmium, are prone to wind (eolian) dispersion and water erosion. Wind dispersion occurs because the fine tailings particles (silty sand-like material) and their associated contaminants are easily suspended into the atmosphere by wind and dispersed throughout the environment as dust particles. Spread of metal toxicants in association with tailings particles, through a combination of wind dispersion and water erosion, has been shown to result in measurable elevated levels in wildlife and humans even significant distances from the tailings site.
A current UA SBRP research project (Project 10) is investigating easy, low-cost ways to re-vegetate mine tailings to reduce both wind dispersion and water erosion. Re-vegetation is done using native plants and optimized to allow the minimum amount of site preparation, fertilizer application, and maintenance. This process is called phytostabilization - the establishment of a vegetation cover using native plants. Key for phytostabilization is that the plants do not accumulate toxic metals in their shoot tissues. Building upon this existing research, the recently awarded NIEHS R01 grant will take the next necessary steps to understand the metal speciation and microbial dynamics in plant and mine tailing systems to inform bioavailability and toxicity of particle-scale metal speciation in plant roots.
This research is both timely and necessary as growth in the US Southwest is exploding and communities are being developed in closer proximity to such tailings sites.