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Arsenic in geothermal sources at the north-central Andean region of Ecuador: Concentrations and mechanisms of mobility

Abstract:

The arsenic content of geothermal hot springs and their sediments in the north-central Andean region of Ecuador has been investigated. The area of study is located between parallels 1°11′N and 1°30′S and includes five provinces. The area is rich in geothermal surface manifestations that are mainly used for medicinal baths in recreational complexes. Unfortunately, water residuals without treatment are released from the recreational facilities to surrounding water bodies. The results indicate that total arsenic in geothermal waters in this region has a range of 2-969 μg As/L, and sediments contain arsenic ranging from 1. 6 to 717. 6 mg/kg. Chemical analyses of sediment samples show the presence of sulfur, iron, aluminum and calcium. A high concentration of natural organic matter was also found in some samples (20-29. 5%); thus sorption and coprecipitation can be the main mechanisms of As immobilization on mineral phases and natural organic matter. © 2009 Springer-Verlag.