Luís Novo
Raina Maier
Distribution and accumulation of metals in soil and vegetation surrounding a molybdenum roasting facility at the Sierrita mine, Pima County
Mining provides essential raw materials for an industrialized society. However, it often comes at a great cost. Mining activities, including mineral processing-related emissions and the disposal of tailings, can be severely hazardous to human health and the environment. In Pima County, copper mining began in the 1870s. Today, the combined output of its three major mines represents nearly a quarter of the US total copper production. The Sierrita mine is an open-pit copper and molybdenum mining complex, whose first claims were recorded in 1895. Today, the Sierrita operation comprises a 100,000-metric ton-per-day concentrator that produces copper and molybdenum concentrate. Molybdenite (MoS2), is one of the by-products in this concentrate, and the main host of rhenium (Re). Following oxidation roasting of the concentrate, Re is released as rhenium heptoxide (Re2O7) with the flue gases, and then dispersed on the soil in its most stable and bioavailable form - the perrhenate ion (ReO4-). Rhenium is one of the scarcest (7 × 10^−8 %) and most broadly dispersed elements on Earth’s upper crust. Because of its rarity and distinguishing physicochemical properties, rhenium is also one of the costliest metals. Recent reports suggest that certain plants may have the ability to accumulate economically profitable amounts of Re, opening a window of opportunity for phytomining – a plant-based technique to retrieve valuable elements from natural and waste substrates. The main objectives of this project are to investigate the occurrence of metal contamination due to molybdenum roasting emissions, and assess the viability of field-scale Re phytomining.
Project type
Projet OHM
OHM(s) involved
  • Pima County
Biogéochimie, Biologie, Écologie, Géologie
Image (put here just a single image)EN DEV


Luís Novo (PhD in Terrestrial Ecosystems, University of Vigo, 2013), is a Researcher and the Head of the Laboratory of Experimental and Applied Phytotechnologies at Department of Geosciences of the University of Aveiro. His main research interests are soil metal pollution, phytomining, phytoremediation, metal hyperaccumulation, synthesis of metal nanoparticles in plants, nanopollution, and metal phytotoxicity. He has published numerous articles and book chapters as first author, and serves as reviewer for 40 renowned international journals. Dr. Luís Novo has participated in several research projects. Please see the attached cv for further information.


Raina Maier
Raina Maier is a Full Professor at the Department of Soil Water and Environmental Science of the University of Arizona, the Director of the University of Arizona’s National Institute of Environmental Health Sciences (NIEHS) Superfund Research Program, and the Interim Director of the University of Arizona Institute of the Environment. She holds a PhD in Microbiology from Rutgers University (1988). Her research interests lie in three focal areas: 1) Phytostabilization of Mine Tailings in Arid and Semi-Arid Environments: Plant-Soil-Microbe Interactions and Metal Speciation Dynamics; 2) Microbial Communities and Activities in Oligotrophic Environments (particularly Caves and Deserts) – with the aim of developing a fundamental understanding of how the microbial component of these systems influences mineral weathering, soil formation and health, and the remediation of any associated metal and organic contamination; and 3) Microbial Surfactants (Biosurfactants) – including discovery...