Assessment of anthropogenic pollution using multiple hydrogeochemical tools and statistical analysis in rural plain basins of the Argentinian Pampean Plain

Abstract

Chemistry of surface water and groundwater can beconditioned by geology, anthropic influence, and exchange of flow between them.The Pampean Plain located in Argentina has gaining streams and mainly ruralactivities. An increase in the concentration of chemical values of surfacewaters with respect to groundwater can be attributed to the anthropogeniccontribution. The aim of thiswork was to identify the natural and/or anthropic processes that determine thechemistry of surface water and groundwater in a sector of the Pampean Plain ofArgentina through the analysis of major and trace elements, 18O and 2Hisotopes, and statistical tools. Asurface water and groundwater sampling network was designed, wherephysicochemical parameters were measured, and samples were taken to determinemajor and trace elements and stable isotopes of water. The results indicate that dissolution, cation exchangeand evaporation are the main processes that determine the chemistry of themajor elements associated with natural processes without showing evidence ofanthropic involvement. Sometrace elements that are statistically associated with major ions evidencewater-sediment interaction within the aquifer. On the other hand, traceelements, as heavy metals, present a higher concentration in surface watercompared to groundwater. This fact, evidences an anthropogenic contributionattributable to anthropic activities. The multivariate statistical analysisallowed discriminating between those trace elements associated with naturalprocesses from those influenced by anthropic activity, even when theseelements´ concentration was very low.