Geochemical tracers combination as powerful tool to assess the impact of anthropogenic source on groundwater

This study presents the first results of the development of geochemical techniques based on the application of multiple tracers including B isotopes, and rare earth elements (REE) on groundwater flowing under an area of a non hazardous waste landfill placed in Abruzzi Region, Central Italy.The aim is to focus on the levels of some trace elements exceeding the law limit values, in order to identify whether the observed concentrations represent a naturally-occurring condition or they are due to an anthropogenic source. To discriminate the natural versus anthropogenic sources of the dissolved trace elements, and to identify the potential pollution sources, it has been carried on a geochemical characterization to determine isotopic ratio δ11B (‰) in conjunction with the rare earth elements (REE) concentrations. In nature, B has two stable isotopes, 11B and 10B with an approximate 11B/10B ratio of 4. It is an ubiquitous element trace element. It is found in in igneous and metamorphic rocks, in clays deposits and it is abundant in marine waters where it is present as borates of evaporitic origin. Boron is a highly mobile element and some clay minerals adsorb boron on surface sites. For this reason, clayey deposits, like the geological context of the study area, represent a potential source of boron. The large isotopic variation of B in nature makes B isotope geochemistry useful for tracing the origin of B in the environment. Boron element is also common in many man made components. The isotopically distinguished signature of borate compounds can be used to evaluate the impact of anthropogenic B on the environment. In combination with isotopes boron, rare earth elements (REE) can be used to discriminate potential anthropogenic contamination source. Recently, REE were used for many high technology products and processes