Le analisi isotopiche come strumento per la valutazione dell'impatto delle discariche RSU sui corpi idrici

Several studies carried out in Tuscany (central Italy) Municipal Solid Waste (MSW) landfills confirm that the analysis of the isotopic ratios ²H/¹H, ¹⁸O/¹⁶O, ³H/H and ¹³C/¹²C is a valuable approach for the evaluation of the landfill impact on surrounding water bodies. Leachates show indeed isotopic values that strongly differ from those found in local natural waters, allowing to identify even low levels of contamination. Tritium (³H) values result to be much higher (normally between 200 and 2.000 TU) than in nowadays meteoric waters and in aquifers (commonly < 10 TU). Dissolved Inorganic Carbon (DIC) in leachate is usually characterized by δ¹³C (V-PDB) ‰ values between +15 and +30 δ‰, whereas natural waters have distinctly lower values (between -25 and 0 δ‰). Relationship between δ¹⁸O‰ and δ²H‰ within leachate is frequently modified too.