Arsenic in volcanic geothermal fluids of Latin America

Lopez, Dina L. and Bundschuh, Jochen and Birkle, Peter and Armienta, Maria Aurora and Cumbal, Luis and Sracek, Ondra and Cornejo, Lorena and Ormachea, Mauricio (2012) Arsenic in volcanic geothermal fluids of Latin America. Science of the Total Environment, 429. pp. 57-75. ISSN 0048-9697

Abstract

Numerous volcanoes, hot springs, fumaroles, and geothermal wells occur in the Pacific region of Latin America. These systems are characterized by high As concentrations and other typical geothermal elements such as Li and B. This paper presents a review of the available data on As concentrations in geothermal systems and their surficial discharges and As data on volcanic gases of Latin America. Data for geothermal systems in Mexico, Guatemala, Honduras, El Salvador, Nicaragua, Costa Rica, Ecuador, Bolivia, and Chile are presented. Two sources of As can be recognized in the investigated sites: Arsenic partitioned into volcanic gases and emitted in plumes and fumaroles, and arsenic in rocks of volcanic edifices that are leached by groundwaters enriched in volcanic gases. Water containing the most elevated concentrations of As are mature Na-Cl fluids with relatively low sulfate content and As concentrations reaching up to 73.6mgL -1 (Los Humeros geothermal field in Mexico), but more commonly ranging from a few mgL -1 to tens of mgL -1. Fluids derived from Na-Cl enriched waters formed through evaporation and condensation at shallower depths have As levels of only a few μgL -1. Mixing of Na-Cl waters with shallower meteoric waters results in low to intermediate As concentrations (up to a few mgL -1). After the waters are discharged at the ground surface, As(III) oxidizes to As(V) and attenuation of As concentration can occur due to sorption and co-precipitation processes with iron minerals and organic matter present in sediments. Understanding the mechanisms of As enrichment in geothermal waters and their fate upon mixing with shallower groundwater and surface waters is important for the protection of water resources in Latin America.


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Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Permanent restricted access to published version due to publisher copyright policy (Elsevier).
Depositing User: epEditor USQ
Faculty / Department / School: Historic - Faculty of Engineering and Surveying - Department of Agricultural, Civil and Environmental Engineering
Date Deposited: 07 Sep 2012 05:36
Last Modified: 21 Jul 2014 05:55
Uncontrolled Keywords: arsenic; geothermal fluids; geothermal system; Latin America; volcanic fluids; ground water; organic matter; surface water
Fields of Research (FOR2008): 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology
04 Earth Sciences > 0403 Geology > 040314 Volcanology
05 Environmental Sciences > 0502 Environmental Science and Management > 050206 Environmental Monitoring
Socio-Economic Objective (SEO2008): D Environment > 96 Environment > 9611 Physical and Chemical Conditions of Water > 961103 Physical and Chemical Conditions of Water in Fresh, Ground and Surface Water Environments (excl. Urban and Industrial Use)
Identification Number or DOI: doi: 10.1016/j.scitotenv.2011.08.043
URI: http://eprints.usq.edu.au/id/eprint/21613

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