87Sr/86Sr as an efficient tool to investigate environmental processes in winemaking: a Campania (Italy) case study.

In the last few years Sr isotope geochemistry has contributed substantially to environmental and food traceability research. This is achievable because soils, plants and waters all have a peculiar Sr isotopic signature (⁸⁷Sr/⁸⁶Sr) inherited from the local geological substratum and affected by geological processes as well as the age and initial rubidium concentration of the rocks. Strontium ions released from the bedrock by weathering processes deriving by the interaction of circulating fluids with rocks, enter the environment and accumulates in water and soils. This reservoir of bioavailable Sr may represent a reliable tracer useful to determine the geographical origin of wines as it is known that strontium is taken first by plant roots, then by grapes, and lastly by wine, with no isotope fractionation when compared to the original ⁸⁷Sr/⁸⁶Sr ratio in the soil and rocks. As a result, the study of the Sr isotope ratio in the final product (wine) links directly to its geological origin thus representing a specific geofingerprint for any selected wine. Based on these premises this work aims at confirming the strong link between the product (wine) and its territory, with the final purpose to make it recognizable and distinguishable from similar products and protecting it from possible fraud and adulteration. In this work the ⁸⁷Sr/⁸⁶Sr systematics has been used to analyze a total of 39 samples (37 soil samples and 2 wine samples) from Campania (Italy). For a better understanding, both total Sr fraction and bioavailable Sr fraction were analyzed in soil samples (rhizospheric soils, bulk soils and samples collected from different horizons) in order to better investigate the environmental processes involved during the wine production cycle.