JUAN IGNACIO GUZMAN, Patricio Faúndez, José Joaquín Jara, Candelaria Retamal

Brines located in the Salar de Atacama are a significant source of lithium worldwide. The extractive method for these minerals is through brine pumping, with subsequent solar evaporation in ponds. In this latter process, part of the water present in brine is evaporated to the atmosphere, leading to the possibility of harvesting lithium and potassium salts. This situation has risen a series of environmental concerns among local stakeholders and international environmental groups; specifically, in terms of water depletion caused by mining activities. However, no comprehensive studies have been carried out to quantify the impact on the water availability of this basin as a consequence of lithium mining. The aim of this study is to contribute to fill in this gap by quantifying the impact of brine and water evaporation over the precipitations in the area, and thus on the water stress at the Salar de Atacama basin.

Through the implementation of a novel methodology based on a VAR model, the potential recharge on the basin is estimated, considering the precipitations associated with water evaporation in the process of lithium extraction. With this information, the Water Stress Index (WSI) over the period 2002-2017 is computed. The results show that comparing the factual and a mining-free counterfactual scenario, the extraction of brine would have had a minor impact on the availability of water in the Salar de Atacama basin.