Black crusts on Venetian built heritage, investigation on the impact of pollution sources on their composition

Abstract

This research deals with the characterization of black crusts collected from several historical buildings in the city of Venice. This city suffers from pollution from the industrial area of Marghera, as well as from the maritime traffic. Black crust can be considered as a passive sampler of pollutants, with particular reference to heavy metals. For this reason, in order to fully characterize those samples, several techniques were used, including scanning electron microscopy, thermogravimetric analysis, laser ablation inductively coupled plasma mass spectrometry, infrared spectroscopy and ion chromatography. This integrated approach allowed us to gain information about the mineralogical phases and the elements within the crusts giving the possibility to identify the pollution sources causing the stone decay within the buildings, as well as the variability in composition depending on the exposure of the analyzed

Study and Characterization of Environmental Deposition on Marble and Surrogate Substrates at a Monumental Heritage Site

“…The low concentration detected may be due to the decomposition of such compound. Since sulphate in the aerosol particulate matter could be of both anthropogenic or marine origin, an apportionment between these two sources has been calculated in accordance with what reported in the literature [37][38][39][40][41]. This approach is based on the fact that sulphate of marine origin is present as sodium sulphate and, as a consequence, sulphate of anthropogenic origin (NSS_SO 4 2− = non-sea salt sulphate) can be calculated from total sulphate by subtracting the contribution from Na 2 SO 4 (SS_SO 4 2− = sea salt sulphate), considering the ratio between these two elements in sea salt.…”

The CRATI Project: New Insights on the Consolidation of Salt Weathered Stone and the Case Study of San Domenico Church in Cosenza (South Calabria, Italy)

“…Calcite and quartz occur due to substrate, while the presence of gypsum can represent a degradation product. In fact, if calcium carbonate is attacked by sulphuric acid generated by the sulphur compounds in the polluted atmosphere, it is transformed into gypsum [29][30][31][32][33][34]. Spectra of the samples SD8, SD11 and SD13 exhibit all the previous bands; and in addition, those related to the presence of the characteristic bands of weddellite (calcium oxalate) peaked at around 1643, 1330 and 783 cm −1 .…”

“…Spectra of the samples SD8, SD11 and SD13 exhibit all the previous bands; and in addition, those related to the presence of the characteristic bands of weddellite (calcium oxalate) peaked at around 1643, 1330 and 783 cm −1 . The presence of this mineral is indicative of an alteration product [30,31,35,36]. Representative IR spectra are shown in Figure 5.…”

Geochemical and Mineralogical Characterization of Construction Materials from Historical Buildings of Ferrara (Italy)

“…The presence of gypsum in the samples C6-1 (sulfated black crust) probably could be related to a high value of sulfur [41]. The façade of the cloister of Santa Maria delle Grazie overlooks a narrow and busy street, this could be one of the reasons to better understand the presence of black crusts in the samples collected on the cloister façade [42][43][44].…”