In Chile, lithium mining is causing the Salar de Atacama to sink

Chile conserves, in its subsoil, some of the largest reserves of lithium in the world, a fundamental material for the ecological transition and therefore increasingly sought after.The extraction of this material, which has undergone a surge in recent years, it is however causing the collapse of the Salar de Atacama, the large saline lake located in the Antofagasta region, in the north of the country.This was discovered by some researchers from the University of Chile, who found that the extraction of brine, rich in lithium, is drying up the aquifers and causing the lake to sink at a worrying rate of 1 or 2 centimeters per year.

Chile is the second largest producer of lithium in the world and, with the advancement of the "ecological transition" and therefore with the increase in demand for lithium batteries, the extraction of this material proceeds at an ever-increasing pace.This, inevitably, has irreversible consequences on the environment.Through the use of data collected between 2020 and 2023 by the SAOCOM-1 satellites, belonging to the Argentine Space Commission for Space Studies, researchers from the University of Chile have in fact observed how the ground beneath the Salar de Atacama is progressively giving way.The decrease is due, in particular, to loss of groundwater, which causes the groundwater to compact and, consequently, the loss of their porosity and permeability, a factor that triggers the sinking of the surface.All of this is caused by mining and water extraction activities:lithium is in fact obtained by evaporation, a process that causes a significant drop in the water level in underground aquifers.According to a 2019 study, cited by Chilean researchers, groundwater levels have decreased by 10 meters in the last 15 years.

Francisco Delgado, researcher at the Department of Geology of the University of Chile and main author of the study, reported that «The subsidence [the lowering of the land, ed.] due to irreversible changes in permeability it can be a very serious problem."Regarding subsidence, Delgado explained that «In Chile, fortunately, we do not have this problem on a large scale and, preliminarily, we believe that this is due to the fact that population density and groundwater pumping occur at very high rates. lower than the places mentioned previously.However, measurements indicate that pumping of lithium-rich brine occurs in the Salar de Atacama at a higher rate compared to the recharge of aquifers".

Those who suffer the consequences of the drastic modification of the environment are indigenous populations who live near the Atacama Salt Flat, whose water resources are thus slowly being dried up.In April this year, with the (declared) intent of protecting local communities, President Boric announced his intention to nationalize the country's lithium reserves.However, more time will be needed to verify whether policies of this kind can actually bring results.

[by Valeria Casolaro]