Phytostabilization of mine tailings in arid and semiarid environments--an emerging remediation technology.
OBJECTIVE
Unreclaimed mine tailings sites are a worldwide problem, with thousands of unvegetated, exposed tailings piles presenting a source of contamination for nearby communities. Tailings disposal sites in arid and semiarid environments are especially subject to eolian dispersion and water erosion. Phytostabilization, the use of plants for in situ stabilization of tailings and metal contaminants, is a feasible alternative to costly remediation practices. In this review we emphasize considerations for phytostabilization of mine tailings in arid and semiarid environments, as well as issues impeding its long-term success.


METHODS
We reviewed literature addressing mine closures and revegetation of mine tailings, along with publications evaluating plant ecology, microbial ecology, and soil properties of mine tailings.


METHODS
Data were extracted from peer-reviewed articles and books identified in Web of Science and Agricola databases, and publications available through the U.S. Department of Agriculture, U.S. Environmental Protection Agency, and the United Nations Environment Programme.


RESULTS
Harsh climatic conditions in arid and semiarid environments along with the innate properties of mine tailings require specific considerations. Plants suitable for phytostabilization must be native, be drought-, salt-, and metal-tolerant, and should limit shoot metal accumulation. Factors for evaluating metal accumulation and toxicity issues are presented. Also reviewed are aspects of implementing phytostabilization, including plant growth stage, amendments, irrigation, and evaluation.


CONCLUSIONS
Phytostabilization of mine tailings is a promising remedial technology but requires further research to identify factors affecting its long-term success by expanding knowledge of suitable plant species and mine tailings chemistry in ongoing field trials.
Mendez
Monica O
MO
Department of Soil, Water, and Environmental Science, University of Arizona, Tucson, Arizona 85721-0038, USA.
Maier
Raina M
RM
D001673:Biodegradation, Environmental; D003247:Conservation of Natural Resources / Q000379:methods; D003889:Desert Climate; D017753:Ecosystem; D004787:Environmental Pollution; D006801:Humans; D007220:Industrial Waste; D019216:Metals, Heavy / Q000378:metabolism; D008906:Mining; D063245:Plant Development; D010944:Plants / Q000378:metabolism / Q000382:microbiology; D014481:United States
D007220:Industrial Waste; D019216:Metals, Heavy