A CONCEPTUAL MODEL FOR UNDERGROUND WATER CONTAMINATION FROM AN OLD MSW LANDFILL

A conceptual model that accounts for the pollution mechanisms of underground waters by an old MSW landfill is presented in detail. Resistivity measures, stratigraphic, chemical and isotopic abundance data have been used in order to provide complementary pieces of information that permitted to "reconstruct" the conceptual model. The mixing process between underground water and leachate has been reconstructed using geochemical characterisation of underground waters based on major salts composition like Chlorides, Sulphates and Carbonates and on Isotopic abundance determination, rather than on the presence of characteristic leachate pollutants like heavy metals, COD or ammonia. Comparison of results allowed to describe a conceptual model for the pollution mechanism that involves sea ingression as one of the means of pollution diffusion in underground waters.