Saline lakes as barriers against pollution: a multidisciplinary overview

Abstract

Saline lakes are subject to numerous environmental impacts closely related to human activities, including mining, desiccation and pollution. These lakes are mostly located in arid and semi-arid regions located in endorheic basins, which combined with the low precipitation and high evaporation rates typical for these regions, may lead to the accumulation of pollutants. Saline lakes are polluted mainly through inputs of agricultural wastewater along with organic and inorganic wastes from domestic and industrial sources. The excessive anthropogenic loading of nutrients, especially nitrogen (N), can result in eutrophication of these ecosystems. Here, the importance of pollution in saline lakes was assessed, placing special emphasis on N pollution and its attenuation in aquatic interfaces. Two main interfaces are present in saline lakes: (1) the sediment-water interface; (2) the freshwater-saltwater interface. While the former is the most important one for microbial turnover, the latter plays also a key role in pollution attenuation based on solute transport by density-driven flows. The study of how saline lakes can attenuate N pollutants (e.g. nitrate) is a step forward in preserving the good ecological status of these ecosystems. This work highlights the need of integrating a wide range of techniques from different disciplines such as limnology, hydrogeology, geochemistry or microbial ecology for such studies. The effective application of conservation policies by managers will depend on the degree of knowledge of these systems.