Geogenic arsenic and other trace elements in the shallow hydrogeologic system of Southern Poopo Basin, Bolivian Altiplano

Ormachea Munoz, Mauricio and Wern, Hannes and Johnsson, Fredrick and Bhattacharya, Prosun and Sracek, Ondra and Thunvik, Roger and Quintanilla, Jorge and Bundschuh, Jochen (2013) Geogenic arsenic and other trace elements in the shallow hydrogeologic system of Southern Poopo Basin, Bolivian Altiplano. Journal of Hazardous Materials, 262. pp. 924-940. ISSN 0304-3894

Abstract

Environmental settings in the southern area of Lake Poopo in the Bolivian highlands, the Altiplano, have generated elevated amounts of arsenic (As) in the water. The area is characterised by a semiarid climate, slow hydrological flow and geologic formations of predominantly volcanic origin. The present study aimed at mapping the extent of the water contamination in the area and to investigate the geogenic sources and processes involved in the release of As to the groundwater. Ground- and surface-water samples were collected from 24 different sites, including drinking water wells and rivers, in the southern Poopo basin in two different field campaigns during the dry and rainy seasons. The results revealed variable levels of As in shallow drinking water wells and average concentration exceeding the WHO guidelines value. Arsenic concentrations range from below 5.2 μg/L (the detection level) to 207 μg/L and averages 72 μg/L. Additionally, high boron (B) concentrations (average 1902 μg/L), and high salinity are further serious concerns for deteriorating the groundwater quality and rendering it unsuitable for drinking. Groundwater is predominantly of the Na-Cl-HCO3 type or the Ca-Na-HCO3 type with neutral or slightly alkaline pH and oxidising character. While farmers are seriously concerned about the water scarcity, and on a few occasions about salinity, there are no concerns about As and B present at levels exceeding the WHO guidelines, and causing negative long term effects on human health. Sediment samples from two soil profiles and a river bed along with fourteen rock samples were also collected and analysed. Sequential extractions of the sediments together with the calculation of the mineral saturation indices indicate that iron oxides and hydroxides are the important secondary minerals phases which are important adsorbents for As. High pH values, and the competition of As with HCO3 and dissolved silica for the adsorption sites probably seems to be an important process for the mobilisation of As in the shallow groundwaters of the region. Continuous monitoring and expansion of monitoring systems are necessary prerequisites for better understanding of the pattern of As mobilisation in the Southern Poopo Basin.


Statistics for USQ ePrint 24137
Statistics for this ePrint Item
Item Type: Article (Commonwealth Reporting Category C)
Refereed: Yes
Item Status: Live Archive
Additional Information: © 2013 Elsevier B.V. Published online 24 Jul 2013. Published version deposited in accordance with the copyright policy of the publisher.
Faculty / Department / School: Current - Faculty of Health, Engineering and Sciences - School of Agricultural, Computational and Environmental Sciences
Date Deposited: 07 Oct 2013 23:09
Last Modified: 14 Jul 2017 02:35
Uncontrolled Keywords: adsorption; alluvial sediments; arsenic; Bolivian Altiplano; groundwater; volcanic rocks
Fields of Research : 04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040608 Surfacewater Hydrology
04 Earth Sciences > 0403 Geology > 040301 Basin Analysis
04 Earth Sciences > 0406 Physical Geography and Environmental Geoscience > 040603 Hydrogeology
Socio-Economic Objective: D Environment > 96 Environment > 9609 Land and Water Management > 960910 Sparseland, Permanent Grassland and Arid Zone Land and Water Management
Identification Number or DOI: 10.1016/j.jhazmat.2013.06.078
URI: http://eprints.usq.edu.au/id/eprint/24137

Actions (login required)

View Item Archive Repository Staff Only