T230 Groundwater Security Toward Sustainable Development

Wednesday, 12 October 2022
8:00 AM - 12:00 PM
406

ELEVATED CONCENTRATIONS OF ARSENIC IN GROUNDWATER USED FOR HUMAN CONSUMPTION IN LAUCA RIVER BASIN, ORURO, BOLIVIA

Paper number: T230-10
Program: Technical Sessions
Time: 10:10 AM – 10:25 AM

Authors

Abstract

Groundwater is the main source of drinking water in rural areas of the Bolivian Altiplano. Recently, a widespread natural arsenic enrichment of groundwater was discovered in different areas of the Bolivian Altiplano, especially in the Poopó lake basin.

Here we present the initial results of a field campaign in which 30 drinking water wells were sampled and analyzed, covering different parts of the Lauca river basin. Field investigations include determination of pH, ORP, electrical conductivity, and temperature using a portable multiparameter instrument and alkalinity using a digital titrator. Arsenic concentrations were obtained using a portable field meter. Water samples were collected in duplicate, samples were filtered for major anions, and acidified for major cation and trace element analyses.

Result indicate that groundwater pH is circumneutral to alkaline in a range of 6.67 to 8.10, the electrical conductivity varies in a range of 206 to 4325 µS/cm, the ORP of sampled wells are relatively oxidized. Predominant water type is Na-Cl-HCO3 with high concentrations of arsenic observed in various water samples ranging from 5 to 630 μg/L. Multiple geochemical mechanism drives mobilization of arsenic from alluvial sediments to aquifers in the Lauca river basin

High concentrations of As can have serious effects on the health of the exposed population and it is necessary to apply low-cost remediation technologies to ensure the safety of drinking water. It is necessary deep investigations for better understand the sources of arsenic and the geochemical mechanism for arsenic mobilization into groundwater, which is probably controlled by weathering, dissolution/precipitation of specific geological materials within the Lauca river basin in Bolivian Altiplano.

Geological Society of America Abstracts with Programs. Vol. 54, No. 6

doi: 10.1130/abs/2022AM-381698

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