Domenico Miriello

Asbestos and other fibrous minerals contained in the serpentinites of the Gimigliano-Mount Reventino Unit (Calabria, S-Italy)

Serpentinites are metamorphic rocks with good technological properties and valuable ornamental characteristics, which have been exploited since ancient times. Actually, their use is limited and monitored in several countries worldwide because they can contain fibrous asbestos minerals that may be carcinogenic. Furthermore, certain types of fibrous minerals can be confused with asbestos, and must therefore be carefully investigated. We have investigated the possible presence of the asbestos and non-asbestos fibrous phases contained in serpentinitic rocks in a meta-ophiolitic sequence from the Gimigliano-Mount Reventino Unit (Southern Italy), which had not been previously assessed. The detection and quantification of asbestos and the correct distinction of the fibrous non-asbestos minerals are very important not only from a scientific point of view, but also from a legislative one. This is especially the case for the administrative agencies that have to take decisions with regards to the implementation of public and occupational health protection measures (e.g., in road yards and quarry excavations). As a consequence of this, serpentinitic rock samples have been characterized in detail through X-ray powder diffraction, scanning and transmission electron microscopy combined with energy-dispersive spectrometry, analytical electron microscopy (SEM–EDS and TEM–AEM), differential scanning calorimetry, thermogravimetry and micro-Raman spectroscopy. Two kinds of asbestos and four kinds of non-asbestos fibrous silicates have been detected in the examined samples. In order of decreasing abundance these are polygonal serpentine, chrysotile, fibrous antigorite, tremolite, gedrite and magnesiohornblende. The size, morphology, crystallinity and chemical composition of the fibres were also discussed, in the light of the possible role these properties could play in the carcinogenic effect on human health.

Cultural Heritage Documentation and Conservation: Three-Dimensional (3D) Laser Scanning and Geographical Information System (GIS) Techniques for Thematic Mapping of Facade Stonework of St. Nicholas Church (Pisa, Italy)

ABSTRACT This article reports the mapping of the stones, including marbles and brick masonry, used for building the facade of the medieval Church of St. Nicholas (XI century ad), one of the most interesting churches in Pisa, due also to the nearby famous octagonal bell tower. Mapping of stone materials was performed using a computer-aided design (CAD)/geographical information system (GIS) software package for storing and processing spatial information of the ashlars, obtained using three-dimensional (3D) laser-scanning data, combined with high-resolution images, and stone-to-stone observations. Based on collected data, the facade of the Church of St. Nicholas appeared mostly composed of rocks belonging to the metamorphic Tuscan sequence, quartzites, and marbles from Mt. Pisano area. Other types of rocks were also observed, as black limestones quarried at some kilometers northwest from Pisa in the Monti d’Oltre Serchio area, white Apuan marbles and Macigno sandstones. Conversely, intarsia appeared mainly made up of serpentinite and, subordinately, red limestones laid in white Apuan and Mt. Pisano marbles.

Mixing and provenance of raw materials in the bricks from the Svevian castle of Rocca Imperiale (North Calabria, Italy)

Bricks from the Svevian castle in Rocca Imperiale (northern Calabria, Italy) were analysed in an attempt to ascertain their provenance. This impressive architectural structure was built by Frederick II of Svevia around the year 1200 and is one of the most significant monuments in Southern Italy. Petrographical and chemical XRF analyses of the trace and major elements were also carried out on any raw materials locally that might have been used in the brick making. This enabled us to locate outcrops of clays and non-plastic elements, which confirm the hypothesis that the materials used were found locally. Detailed chemical and petrographic analyses of the bricks, clays and sands have shown that the temper added to the clay in the brick-making process corresponds to a mix of Pliocene sand and sand from the bed of the Canna stream.

Naturally occurring asbestos (NOA) in rock and soil and relation with human activities: the monitoring example of selected sites in Calabria (southern Italy)

The major aim of our research is to assess the occurrence, within the serpentinites and serpentinite-derived soils located in the area of Sila Piccola (northern Calabria), of asbestiform minerals that could be potentially harmful for human health. At this purpose, nine serpentinite rock samples and three agricultural soils have been collected nearby two inhabited centres (Gimigliano and Conflenti towns) and characterized in detail by means of Polarized Light Microscopy (PLM), X-Ray Powder Diffractometry (XRPD), Scanning Electron Microscopy combined with Energy-Dispersive Spectrometry (SEM/EDS). Further characterization by Differential Scanning Calorimetry (DSC), Thermogravimetric (TG) and by μ-Raman spectroscopy (μ-R) have allowed the discrimination among the three serpentine polytypes. Serpentinites from Gimigliano mainly consist of lizardite, antigorite while chrysotile is the dominant asbestos phase in the samples from Conflenti. Moreover in both investigated sample groups asbestos tremolite- actinolite was also detected. Furthermore, high amounts of chrysotile and asbestos tremolite-actinolite were found in agricultural soils, suggesting that human activities can disturb and provoke the release of inhalable asbestos in the atmosphere, triggering thus mechanisms of hazardous exposition for population.

Naturally occurring asbestos: potential for human exposure, San Severino Lucano (Basilicata, Southern Italy)

In recent years, environmental exposure to naturally occurring asbestos (NOA) has been shown to be a cause of several types of lung disease, which may occur when NOA outcrops are in proximity to residential areas. In this study, we present the results of our investigation of NOA hosted in outcrops of serpentinites in Basilicata region (Southern Italy), which could be potentially harmful to human health. For this purpose, fifteen serpentinite rock samples collected within and near the village of San Severino Lucano were characterized in detail by optical microscope (OM), X-ray powder diffraction (XRPD), thermal analysis (TG/DSC/DTG/DDSC), scanning and transmission electron microscopy combined with energy-dispersive spectrometry, analytical electron microscopy (SEM/EDS and TEM/AEM). Chrysotile and asbestos tremolite or asbestos actinolite were identified in all samples. The NOA in these outcrops could be subject to weathering processes and/or human activities, which generate airborne particles, thus exposing the neighbouring populations to a series of health risks. The size and morphology of NOA are also discussed, regarding the carcinogenic effect that these factors may have on human health. Due to the health risks associated with disturbing NOA-bearing rock, an asbestos exposure control plan must be instituted.

Relationships between mineralogical and textural factors in respect to hydric dilatation of some sandstones and meta-sandstones from the Northern Apennine

This paper presents the results of a study of the linear hydric dilatation of some sandstones and meta-sandstones and its relations with their mineralogy, texture and physical properties. The ultimate aim is to identify the main factors and mechanisms responsible for hydric dilatation in silicoclastic rocks. The study has been conducted on various rock types selected for their different mineralogical, textural and physical properties: Macigno, Monte Senario and Manciano sandstones, and Pietra del Cardoso and Monte Pisano Quartzite meta-sandstones. In the selected samples, linear hydric dilatation measured perpendicular to rock bedding or foliation ranges from 0.15 to 1.01 mm/m. The results herein obtained indicate that the main factors influencing the degree and kinetics of dilatation upon water uptake are the amount, size and size distribution of the open pores, the pore shape and spatial distribution, the preferential orientation of phyllosilicates and the presence of significant amounts of expansible clayey components. These factors combine and interact in various ways to generate the different hydric behaviours observable in these stones. In particular, the linear hydric dilatation depends at first on the pore dimensions in respect to the absolute water absorption.

Compositional study of mortars and pigments from the “Mosaico della Sala dei Draghi e dei Delfini” in the archaeological site of Kaulonía (Southern Calabria, Magna Graecia, Italy)

This work focuses on the archaeometric study of mortars and pigments coming from the “Mosaico della Sala dei Draghi e dei Delfini”, the oldest and most complex Hellenistic mosaic of the Magna Graecia, located in the Hellenistic baths of the archaeological site of Kaulonía (Southern Calabria, Italy). From this mosaic, mortar samples belonging to different stratigraphic sequences and coloured filling mortars were analyzed through polarized optical microscopy (OM), microanalysis scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS) and Raman spectroscopy.To study the executive technique and the typology of pigments used in the mosaics of the Magna Graecia, it was considered another mosaic of Kaulonía: the “Mosaico della Casa del Drago”, the first polychrome mosaic discovered in the ancient city, which represents the figure of the dragon. From this last mosaic, one sample of painted surface lime was collected and compared with the coloured filling mortars of the Mosaico della Sala dei Draghi e dei Delfini.In addition, a sample of Jurassic limestone with red mineralizations, from the north of the city of Stilo, was sampled to study the provenance of the pigments used.To this day, research has not yet focused on the compositional study of the Hellenistic mosaics of Kaulonía. For this reason, this work wants to give, for the first time, information about the executive techniques of these mosaics and the composition of mortars and pigments, increasing the knowledge on the production technology of the mosaic in the Hellenistic period and, in particular, in the archaeological site of Kaulonía.

Spectroscopic, microchemical and petrographic analyses of plasters from ancient buildings in Lamezia Terme (Calabria, Southern Italy).

This work shows the results of the spectroscopic, microchemical and petrographic study carried out on six plasters coming from three important residential buildings of the 18th century, located in Lamezia Terme (Catanzaro, Southern Italy). To study the provenance of the raw materials used to make the plasters, one sample of limestone and two samples of sand were also collected from the quarries near Lamezia Terme and compared with the historical plasters. Samples were studied by polarized optical microscopy (OM), X-ray powder diffraction (XRPD), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDS) and Raman spectroscopy. The results of these analyses allowed to determine the mineralogical, petrographical and chemical characteristics of the plasters, identify the pigments used for their coloration and provide useful information about the building techniques, the raw materials employed and the production technology of plasters during the 18th century in Lamezia Terme. SEM-EDS microanalysis also revealed the presence of gold and silver on the surface of two samples.

Thermographic Survey at Hagia Sophia: Main Arches, Pendentives and Tympana

ABSTRACT Hagia Sophia is one of the oldest and most complex existing monuments. Many unanswered questions are still open on the historical and constructive evolution of this monument. The boundaries between the different construction phases and the details of the masonry and materials used in the various phases are still not defined with precision. The thermographic survey, carried out inside the monument, made it possible to answer some of these questions by specifying the exact location of the past interventions and the variability of the materials employed allowing a better understanding of the constructive history of the monument. The technique was applied at a great distance and in normal environmental conditions, taking advantage of the high thermal sensitivity of the instrumentation. The results achieved confirm the validity of the technique in the study of ancient buildings.

Behaviour of epoxide resin used to protect the Rupe di Tropea (southern Calabria, Italy)

The present work aims to study the behaviour of the protective resin tested on a small portion of sandstone rock along the Rupe di Tropea. The Rupe di Tropea, located on the northern coastal edge of the Capo Vaticano promontory (Southern Calabria, Italy), is characterized by frequent landslide phenomena involving large amounts of detritus related to the weathering processes of arenitic sediments. An experimental resin was used in a small portion (the tested surface) of the arenitic sediments of the Rupe di Tropea, in order to check its behaviour against fast erosion processes during the intervention of slope consolidation in 1998. The study of resin was performed trough laboratory tests and petrographic analysis. The results of analysis shown that the resin type was epoxy resin and it has penetrated the rock to a depth of about 2 mm. The tested surface of the arenitic sediments has shown during the last 17 years a good resistance to erosion with only a slight opacization of the applied resin. However, the tested surface is characterized by higher content of soluble salts then the non-treated surface due to the infiltration of water enriched in soluble salts related to the marine aerosol. In these conditions the soluble salts crystallize in the rock pores and between the prismatic cleavage of the micas producing an increase of physical stress and consequent exfoliation processes of the resin surface layer. After a long period, this produces a rock breakdown when these soluble salts evaporate, leaving salt crystals behind. Thus, the epoxy resin improves the resistance to erosion only in a restricted period and without infiltration of water. Over time the infiltration of moisture may introduce dangerous soluble salts. Thus, if the treated surface is not well isolated from the water infiltration, the resin produces after a long period an increase of the crystallization of the soluble salts with consequent important exfoliation processes of the treated area.