Andean springs: An overview of heavy metals concentrations in a pristine cryogenic environment

SILEO, N; DAPEÑA, C; BOTTEGAL, E; TROMBOTTO, D

Delhi

Congreso; 36th International Geological Congress; 2020

Water resulting from ice-rich permafrost degradation exhibits distinctive chemical characteristics visible in the trace elements concentrations. In this contribution we focus on analyzing particularly those water discharge from springs located at the foot of 5 important rock glaciers found in the Vallecitos basin, in the Cordillera Frontal (Central Andes) of Mendoza, Argentina. A comparison is made between 6 different sampling sites, taking into account the concentrations of Cd, Ni, Zn, Mn, As and Fe. We also present a time series of the concentration of each element at each site. This research showed that the greater or lesser presence of trace metals dissolved in water emerging from springs located at the foot of the rock glaciers studied, would be linked to the intrannual climate variability, being temperature fluctuations and precipitation the most important factors that governs all the dynamic processes of the study area. In addition, the direction of the underground flow will determine whether or not the water will come into contact with the fresh debris of glacial origin that contains more reactive surfaces. Therefore high concentrations of some heavy metals such as Cd (1- 5μg/l), Ni (25-250 μg/l) and Zn (100- 1200 μg/l) which in most cases exceed the guidelines for drinking water stablished by the WHO (2017), are associated with the summer period with the expected increase in water volume as a product of the thawing of the active layer and melting of glacier ice.