Hydrochemical assessment with respect to arsenic and other trace elements in the Lower Katari Basin, Bolivian Altiplano

Israel Quino Lima, Mauricio Ormachea Muñoz, Oswaldo Eduardo Ramos Ramos, Prosun Bhattacharya, Raul Quispe Choque, Jorge Quintanilla Aguirre, Ondra Sracek

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Hydrochemical investigations of groundwater and surface water were carried out to better understand the spatial distribution of As, major ions and trace elements. The study was carried out to evaluate the sources of dissolved species and elucidate the processes that govern the evolution of natural water in the Lower Katari Basin. The study area is close to the Titicaca Lake (Cohana Bay) formed by sediments of the Quaternary system, deposited in the fluvio-glacial to fluvio-lacustrine environment and geologic formations of the Devonian and Neogene system of volcanic origin. The study area has several environmental problems mainly caused by contaminants such as heavy metals, nutrients, and bacteria. These problems are linked to the urban and industrial wastes, natural geologic conditions, and mining activities carried out upstream of the Katari Basin, where rivers discharge into the Cohana Bay. A total of 37 water samples were collected during wet season, 31 groundwater samples including drinking water wells and six surface water samples. The hierarchical cluster analysis and principal component analysis were applied to hydrochemical data. Results show high salinity in groundwater related to the evaporation causing serious problems for the groundwater quality and rendering it unsuitable for drinking. Dissolved As concentration ranges from 0.7 to 89.7 μg/L; the principal source of As could be the alteration of volcanic rocks, more than 48% of the shallow groundwater samples exceeded the WHO guideline value for As and more than 22% for NO3 -. Groundwater has neutral to slightly alkaline pH, and moderately oxidizing character. The groundwater chemistry reveals considerable variability, ranging from Na-SO4,Cl type through mixed Na-HCO3 type and Ca,Na-HCO3,Cl type. The distribution of trace elements shows a large range of concentrations. Speciation of As indicates that the predominant oxidation state is As (V). The geochemical modelling indicates that As could be associated with iron oxides and hydroxides which are probably the most important mineral phases for the As adsorption. The spatial distribution and the variation of dissolved As concentration in groundwater is governed by the variability in geological characteristics of the region that raises a significant concern about drinking water quality.

Original languageEnglish
Pages (from-to)281-293
Number of pages13
JournalGroundwater for Sustainable Development
Volume8
DOIs
StatePublished - Apr 2019

Bibliographical note

Funding Information:
The financial support of this research by the Swedish International Development Cooperation Agency (Sida Contribution: 75000553 ) is gratefully acknowledged. We thank to Stéphane Guédron and Celin Duwig at the Institute of Research for Development (IRD) - Bolivia for their analytical support and technical assistance. We extend our sincere appreciation to Efrain Blanco and Edson Chalco at the Chemical Research Institute, Universidad Mayor de San Andres for field work as well as Hermenegildo Fernandez for field support.

Publisher Copyright:
© 2018

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