Abstract

BURGOS, Humberto; GARFIAS, Jaime; MARTEL, Richard  and  SALAS-GARCIA, Javier. Spatio-temporal characterization of arsenic distribution in a karst aquifer in the south of the State of Mexico. Bol. Soc. Geol. Mex [online]. 2021, vol.73, n.1, 00007.  Epub Oct 11, 2021. ISSN 1405-3322.  https://doi.org/10.18268/bsgm2021v73n1a160820.

Diversity of anthropogenic, geological and climatic factors are related to the conformation of the physicochemical properties of groundwater in a specific area, which should be studied using appropriate approaches. To achieve this, the main objective of this research was aimed at assessing the current situation of the resource emphasizing the individualization of the main factors that determine its temporal-space evolution in the municipalities of Ixtapan de la Sal and Tonatico. The methodological approach used consisted of a combination of hydrochemical, multivariate statistical and geostatistical analysis techniques, applied to the physicochemical parameters measured in thermal, non-thermal, surface sources and wells. For 2015 and 2019, the results show that two types of water predominate: Ca2+-HCO3- and Na+-Cl-. A third group, Ca2+-Mg2+-Cl-, evidences mixing processes between thermal and non-thermal waters. Additionally, the dissolution of halite, carbonate minerals (dolomite and calcite) and magnesium sulfate is predominant in the majority ionic conformation. Principal components analysis confirms two important processes: (1) salinity and (2) alkalinity, related to geogenic and anthropogenic factors. The geostatistical modeling, carried out by ordinary kriging, shows that water quality decreases in a south-west to north-east direction, involving arsenic as the main quality limitation factor. It can be concluded that a combined approach, which includes hydrochemical analysis and statistical techniques, offers a viable alternative for the study of the physicochemical evolution of groundwater, the implementation of which can be extrapolated to aquifers of a similar nature.

Keywords : Geostatistics; Principal Components Analysis; Arsenic; Hydrogeochemistry; Ixtapan de la Sal; Tonatico.