Assessment of arsenic mobility in a shallow aquifer from Bevera Valley Basin (Northern Italy)

Abstract

Elevated levels of arsenic (As) have been reported from clay peat and silt aquifer systems in the Bevera Valley Basin, Northern Italy. A sampling survey was carried out on 17 monitoring boreholes completed in the bedrock aquifer. All collected samples were analyzed for major ion concentrations and trace element chemistry. Parameters like pH, temperature, electrical conductivity (EC), dissolved oxygen (DO), and redox potential (Eh) were also measured in situ using digital instruments. Geochemical analyses reveal that groundwater contains high As concentrations, reaching up to 666.5 μg/l, over the Italian threshold (Legislative Decree 152/2006). Then, conventional graphical plots and geochemical modeling techniques were applied to evaluate the geochemistry of As and other trace elements and the mechanisms of their release in groundwater, verifying if high concentrations are due to natural or anthropogenic origin. This study aims to investigate groundwater aquifers in order to define sources and mechanism involved in As release from aquifer sediments and study the relationship with iron (Fe) and manganese (Mn) concentrations.