The impact of unconfined mine tailings in residential areas from a mining town in a semi-arid environment: Nacozari, Sonora, México: Nacozari, Sonora, Mexico

Diana María Meza Figueroa, Agustín Gómez Álvarez, Raina M. Maier, Margarita De La O Villanueva, Alan Moreno-Zazueta, Jacinto Rivera, Alberto Campillo, Christopher J. Grandlic, Ricardo Anaya, Juan José Palafox Reyes

Research output: Contribution to journalArticlepeer-review

133 Scopus citations


Past mining activities in northern Mexico left a legacy of delerict landscapes devoid of vegetation and seasonal formation of salt efflorescence. Metal content was measured in mine tailings, efflorescent salts, soils, road dust, and residential soils to investigate contamination. Climatic effects such as heavy wind and rainfall events can have great impact on the dispersion of metals in semi-arid areas, since soils are typically sparsely vegetated. Geochemical analysis of this site revealed that even though total metal content in mine tailings was relatively low (e.g. Cu= 1000 mg kg(-1)), metals including Mn, Ba, Zn, and Cu were all found at significantly higher levels in efflorescence salts formed by evaporation on the tailings impoundment surface following the rainy season (e.g. Cu= 68,000 mg kg(-1)). Such efflorescent fine-grained salts are susceptible to wind erosion resulting in increased metal spread to nearby residential soils. Our results highlight the importance of seasonally dependent salt-formation and wind erosion in determining risk levels associated with potential inhalation or ingestion of airborne particulates originating from contaminated sites such as tailings impoundments. In low metal-content mine tailings located in arid and semi-arid environments, efflorescence salts could represent a human health risk and a challenge for plant establishment in mine tailings.
Original languageAmerican English
Pages (from-to)140-147
Number of pages8
Issue number1e
StatePublished - 1 Sep 2009

Bibliographical note

Funding Information:
The research was supported by EPA-STAG Grant to US–Mexico Binational Center for Toxicology and Environmental Sciences (R. Maier and D. Meza-Figueroa), by Grant 2 P42 ES04940-11 from the National Institute of Environmental Health Sciences. Superfund Basic Research Program, NIH (R. Maier), and by a Technical Assistance Contract to Universidad de Sonora by BECC and EPA Region 9 (D. Meza-Figueroa). Opinions in the paper do not constitute an endorsement or approval by the funding agencies and only reflect the personal views of the authors. The authors are grateful for the comments of two anonymous reviewers. Ana María Pérez provided invaluable technical assistance with acid digestion of samples. Victor del Castillo provided field assistance. The authors also thank Dr. Edward Surbbrugg from Tetra Tech Co. for his assistance in XRF-metal analysis in field. Finally, the authors thank the residents of Nacozari and surrounding areas for their gracious assistance during sample collection for this study.


  • Dust
  • Efflorescence salts
  • Metals
  • Wind-dispersion


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