The impact of unconfined mine tailings in residential areas from a mining town in a semi-arid environment: Nacozari, Sonora, Mexico.
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.
Meza-Figueroa
Diana
D
Departamento de Geología, Universidad de Sonora, Rosales y Encinas, Hermosillo, Sonora, Mexico. dmeza@ciencias.uson.mx
Maier
Raina M
RM
de la O-Villanueva
Margarita
M
Gómez-Alvarez
Agustín
A
Moreno-Zazueta
Alan
A
Rivera
Jacinto
J
Campillo
Alberto
A
Grandlic
Christopher J
CJ
Anaya
Ricardo
R
Palafox-Reyes
Juan
J
D016000:Cluster Analysis; D004391:Dust / Q000032:analysis; D004777:Environment; D006798:Housing; D006801:Humans; D007220:Industrial Waste / Q000032:analysis; D019216:Metals, Heavy / Q000032:analysis; D008800:Mexico; D008906:Mining; D012987:Soil / Q000032:analysis; D012989:Soil Pollutants / Q000032:analysis
D004391:Dust; D007220:Industrial Waste; D019216:Metals, Heavy; D012987:Soil; D012989:Soil Pollutants