Peatbogs and exploitation of Lithium. Coexistence is possible?

NAVARRO CARLOS; IZQUIERDO ANDREA ELISA; CASAGRANDA ELVIRA

San Salvador de Jujuy

Workshop; 3rd International Workshop on Lithium, Industrial Minerals and Energy; 2016

IWliME

Peatlbogs are wetlands present in the Puna ecoregion in Argentina. Its function is to regulate water resources, and its high productivity is used as a food source for wild and domestic animals. They are important carbon sinks since the organic matter produced by plants accumulates because decomposition rates are lower than the net primary productivity rates.In order for a peatbog be developed and maintained over time the combination of different environmental conditions, among which are required: 1- positive water balance with low fluctuations in the water level, 2 - substrate with low levels of nutrients (Kuhry and Vitt 1996)[5], 3 - low input of nutrients to water, 4- low temperatures. The modification of one of these conditions can push the ecosystem of the peat bog outside their resilience area and start losing porosity and water regulation capacity (Benavides 2013)[1].It has been shown that peatbogs are extremely sensitive to environmental changes, whether they be they climatic, hydrological or biogeochemical (nutritional), changing its function as sinks to carbon sources, and in the worst case to major emitters of methane ( Vasander and Kettunen 2006 Vitt 2006)[8].The vertical structure of the soil under the coverage of a peatbog clearly presents two zones with different dynamics. The oxygenated surface zone is associated with intermittent water saturation, and under it there is another area, permanently saturated and poor in oxygen (anoxic zone). Decomposition rates are different in both areas. In the oxygenated zone, the decomposition may be faster compared to the anoxic. That is why maintaining a stable level of water is essential to ensure that decomposition rates are maintained at low levels in relation to productivity.In recent years, lithium has gained importance as a key element in the manufacture of batteries and electric propulsion vehicles, and our country occupying third place as a world producer of this metal.Lithium extraction requires pumping brines which can lead to excessive pressure and cause a very marked decrease in the water table (Espinosa 2011)[3]. This depression of the water table may affect wetlands irreversibly changing rates of decomposition, transforming peatbogs into a source of CO2 and generating a loss in the capacity of these in water regulation. The purpose of this study is to provide a description of the peatbogs that are present in the Puna watersheds where active mining producers are currently operating.In the sub-watersheds Olaroz-Cauchari and Hombre Muerto there are 109 peatbogs mapped by Izquierdo et al. 2015[4] (Fig. 1) of which 8 are large peatbogs (> 50 ha), 32 are medium (10-50 hectares) and 69 are small (