A geochemical approach was applied to understand the factors controlling the mobilization of As and trace elements (TEs) in mining areas of the Poopó and Antequera River sub-basins on the Bolivian Altiplano. A total of 52 samples (surface, groundwater and geothermal water) were collected during the rainy season (2009). Arsenic, Cd and Mn concentrations exceed World Health Organization (WHO) drinking water guidelines and Bolivian regulations for drinking water in 28 groundwater samples, but Cu, Ni, Pb and Zn do not. Arsenic, Cd, Mn, Pb and Zn concentrations exceed World Health Organization guidelines for drinking water and Bolivian regulations Class A standard for discharge to water bodies in 20 surface water samples, whereas levels of Cu do not, and Ni and Fe rarely exceed regulation and guideline values. Factor analysis was applied to 18 hydrochemical parameters of 52 samples. Five factors for groundwater (plagioclase weathering, dissolution of gypsum and halite, TEs mobilization at acidic pH, sulfide oxidation, and release of As) account for 86.5% of the total variance for Antequera and 83.9% for Poopó sub-basins. Four factors for surface water data (weathering and mobilization of TEs influenced by pH, dissolution of evaporate salts, neutralization of acid mine drainage, and As release due to dissolution of Mn and Fe oxides) account for 91% of the total variance in Antequera and 96% in Poopó sub-basins. The As and TEs mobilized in these regions could affect the local water sources, which is a prevalent concern with respect to water resource management in this semi-arid Altiplano region. Presence of both natural and anthropogenic sources of contamination requires careful monitoring of water quality.
Bibliographical noteFunding Information:
This research was funded through the Swedish International Development Cooperation Agency in Bolivia (Sida Contribution: 7500707606 ) and managed by the International Science Programme (ISP), Uppsala University. The authors also acknowledge the support of the CAMINAR project ( INCO-CT-2006-032539 ) funded by the International Cooperation section of the European Commission under the 6th Framework Programme. M. French is funded by a joint initiative between the University College London Institute for Risk and Disaster Reduction and the Catholic Agency for Overseas Development. We extend our sincere appreciation to Elvira Guisbert and Israel Quino for the configuration of maps as well as Moises Calliconde for clarifying the electrochemical concepts. We gratefully acknowledge the analytical support of Efrain Blanco and Liliana Flores at the Instituto de Investigaciones Químicas, UMSA, La Paz, and Ann Fylkner, Monica Löwén and Bertil Nilsson at the Division of Land and Water Resources Engineering, KTH Stockholm, for the major anion analyses. Magnus Mörth at the Department of Geological Sciences, Stockholm University, is acknowledged for the trace element analyses. Additionally, appreciation is given for the constructive comments and suggestions provided by Luis F. Cáceres at Especialidades Químicas (EQ), Dipti Halder and Ashis Biswas at KTH. The detailed comments of an anonymous reviewer which helped to improve the manuscript are thankfully acknowledged.
© 2014 Elsevier B.V..
- Bolivian Altiplano
- Poopó basin
- Surface water
- Trace elements