Geochemistry of naturally occurring arsenic in groundwater and surface-water in the southern part of the Poopo Lake basin, Bolivian Altiplano

Ormachea Munoz, Mauricio and Garcia Arostegui, Jose L. and Bhattacharya, Prosun and Sracek, Ondra and Garcia Moreno, Maria E. and Kohfahl, Claus and Quintanilla Aguirre, Jorge and Horner Diaz, Jorge and Bundschuh, Jochen (2016) Geochemistry of naturally occurring arsenic in groundwater and surface-water in the southern part of the Poopo Lake basin, Bolivian Altiplano. Groundwater for Sustainable Development, 2-3. pp. 104-116. ISSN 2352-801X

Abstract

Groundwaters from shallow aquifers and surface water from rivers of the southern part of Poopó Lake basin within the Bolivian Altiplano have significant quality problems such as high salinity and high concentrations of arsenic (As). The extent of As contamination is observed in the studied groundwater over large parts of the study area. Surface-waters are generally alkaline (pH 8.2–8.7) and oxidizing with dissolved oxygen (DO) concentrations in a range of 2.5–6.6 mg/L The water chemistry is predominantly of Na–Cl–HCO3–type, with concentrations of dissolved As in the range of 8.6–117 µg/L with As(V) as the main aqueous species. The concentration of Li varies in the range of 1.1–4.4 mg/L, while other trace elements occur in low concentrations. Groundwaters have a very large range of chemical compositions and the spatial variability of As concentrations is considerable over distances of a few km; dissolved As in groundwater spans over 4 orders of magnitude (3–3497 µg/L), while concentrations of Li have a range of 0.05–31.6 mg/L. Among the investigated drinking-water wells, 90% exceed the WHO guideline value of 10 µg As/L. Electrical conductivity ranges between 295 and 20,900 µS/cm; high salinity is resulting from evaporation under ambient semi-arid climatic conditions. The pH values of the groundwaters are generally slightly alkaline (5.5–8.7) and universally oxidizing, under these conditions As(V) is the prevalent specie. Groundwater As correlates positively with pH, electrical conductivity, Cl−, Na+, HCO3 −, Ca2+ and SO4 2−. Weathering/dissolution of carbonates, evaporites, halite and plagioclase minerals incorporate Na+ and HCO3 − in solution with consequent pH and alkalinity increase; these are favorable conditions for high mobility of As species. Stable isotopic signatures indicate recharge at the Altiplano with seasonal effects. All surface water and some groundwater samples are enriched due to evaporation, which probably increased concentration of dissolved As


Statistics for USQ ePrint 30839
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: Files associated with this item cannot be displayed due to copyright restrictions.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Civil Engineering and Surveying
Date Deposited: 07 Apr 2017 00:06
Last Modified: 06 Nov 2017 07:13
Uncontrolled Keywords: Altiplano; arsenic; Bolivia; drinking water quality; geochemistry
Fields of Research : 05 Environmental Sciences > 0502 Environmental Science and Management > 050204 Environmental Impact Assessment
05 Environmental Sciences > 0502 Environmental Science and Management > 050205 Environmental Management
05 Environmental Sciences > 0502 Environmental Science and Management > 050206 Environmental Monitoring
Socio-Economic Objective: D Environment > 96 Environment > 9609 Land and Water Management > 960908 Mining Land and Water Management
Identification Number or DOI: 10.1016/j.gsd.2016.04.002
URI: http://eprints.usq.edu.au/id/eprint/30839

Actions (login required)

View Item Archive Repository Staff Only