A preliminary study on black crusts from the Monumental Cemetery of Milan

This study is aimed at the characterization of black crusts taken from funerary monuments placed in the galleries of the Monumental Cemetery of Milan. Black crusts are degradation patinas that formed on carbonate stone surfaces by sulphation reaction. Sulphates formed by this reaction produce incrustations which incorporate various polluting particles (such as carbonaceous particles and heavy metals) that are the catalysts of this reaction. For this reason, black crusts can be considered passive samplers of pollutants over time. To characterize black crusts, different techniques have been used such as SEM-EDS, FT-IR / ATR, IC and TGA. This methodological approach made it possible to obtain information on the chemical and mineralogical composition of the crusts, and also on the pollution sources that have induced the stone decay.