The impact of Li-bearing pegmatite mining on the dissolved geochemical signature of a mountain stream in the Pampean ranges, Central Argentina

Abstract

The contamination of aquatic systems due to mining activities constitutes a great concern of the global mining industry, but only a few studies have specifically addressed the impact of Li-pegmatite mining on water quality. In order to provide data on this type of systems, we assessed the impact of mining activities carried out in a lithium-rich pegmatite of the Sierras Pampeanas, central Argentina, on the chemical composition of stream waters draining the site. In addition, we evaluated the occurrence of Li background anomalies in stream waters at basin scale. To achieve these goals, we analyzed the dissolved major and trace element composition of water samples collected upstream and downstream of the mine, characterized spatial trends, and identified elemental anomalies in comparison with the background chemical composition of stream waters in nearby watersheds. The obtained results reveal that mining activities in the study area do not represent a source of pollution to stream waters draining the mine, while dissolved Li concentrations higher than those measured in nearby basins may be a useful mineralization indicator in the early stages of this type of Li ores exploration, as it points to potentially fertile protoliths for the generation of Li-enriched magma.