Search

Air pollution usually derives in the development of black crusts on the surface of cultural heritage materials. A methodological approach for the morphological, mineralogical and chemical characterization of black crusts developed on limestone on historic buildings of Cairo, Milano, Budapest and Madrid, besides suspended and settling particulate matter, has been carried out. By means of traditional techniques, such as POM, XRD, SEM-EDS and FT-IR, combined with innovative application of laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), a complete characterization in terms of trace elements distribution (including heavy metals) from the black crusts and host limestone has been achieved. Some studied areas display high levels of pollutants and important concentration of heavy metals (Cd, Cu, Pb, Ni, Zn) in the suspended dust (El-Bady, 2014). Within laminar and dendritic black crusts high concentration of gypsum was recorded with increased amount of different elements and metals (Si, Al, Ti, Fe) especially derived from atmospheric inputs and, in particular, by anthropogenic pollution; in dust samples siliceous fly-ash particles are more common than carbonaceous ones and mineral fragments representing windblown particles were also detected (Perez-Monserrat et al., 2011; Török et al., 2011). Heavy metals content (Pb, Zn) are higher in black crust than in substrate, suggesting that polluted atmosphere has a great influence on their formation. Moreover, some specific heavy metals tend to migrate from the crust to the unaltered stone, becoming catalysts for new crust (Barca et al., 2014; La Russa et al., 2014). Black crusts composition entails markers to evaluate the major combustion sources responsible for stone decay and the changes on the used fuels over time. As trace element concentration is directly related with environmental conditions, the study of black crusts can be a marker for human health.

Itinerario científico didáctico en el que se muestran las piedras y materiales cerámicos empleados en la construcción de las facultades de Medicina, Farmacia y Odontología de la Universidad Complutense de Madrid (UCM).

Itinerario científico que atiende a algunos de los puentes históricos del río Guadarrama, al entorno natural y a sus materiales de construcción

During the last decades, many studies have been carried out on environmental monitoring in specific sites aiming at their protection and conservation; however, researches focused on the direct implications, in terms of quantitative evaluation of stone deterioration, of these monitoring actions are still scarce. This experimental work aims at monitoring the degradation processes affecting historical buildings constituted by carbonate stones. Specifically, specimens of Carrara marble and two limestones largely used in the Sicilian Baroque architecture, namely Noto and Comiso stones, were exposed outdoor in two Italian sites (Catania and Palermo), which are characterized by different environmental conditions. The field exposure test lasted two years. Both the substrates and the deposited particulate collected at the end of the exposure underwent several analytical investigations including: i) optical microscopy, mercury intrusion porosimetry, colorimetric analysis and roughness analysis, for the characterization of stone substrates before exposure; ii) ion chromatography (IC), infrared spectroscopy analysis (FT-IR) and inductively coupled plasma mass spectrometry (ICP-MS), for the characterization of the particulate deposited on stone surfaces. The obtained results highlighted blackening and yellowing processes of the carbonate substrates, chiefly on those specimens exposed in Palermo where such processes were more noticeable. Furthermore, the high concentration of sulphates and heavy metals detected (mainly in Palermo site) pointed out that both cities are mainly interested by mobile emission sources such as vehicular traffic. Additionally, analyses demonstrated the key-role of intrinsic features of the lithotypes in the degradation processes. In this regard, the higher porosity and surface roughness of Noto stone explains the major deposition of particulate with respect to the other two examined carbonate rocks., Roughness analyses were carried out thanks to the financial support of the Community of Madrid “Geomateriales 2 programme (S2013/MIT-2914)”.