Teresa Critelli

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.

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.

Preliminary geochemical and geological characterization of the thermal site of Spezzano Albanese (Calabria, South Italy)

Waters discharging at the Spezzano Albanese spring come from a deep circuit hosted in the Ophiolitic rocks of the Diamante Unit (phyllites and metabasalts, Liberi et al., 2006; Vespasiano et al., 2012b). The unit contains a warm deep aquifer acting as a sort of well-mixed reservoir; during the ascent the waters interact with Tertiary and Quaternary deposits (conglomerates, sands, gypsum and clays with levels of halite) that give them a characteristic composition with near neutral pH value of 7.05 to 7.57, outlet temperatures of 20.16° to 26.6°C, variable redox potentials (–0.25 to 0.28 V) and total dissolved solids from 848 to 9720 ppm.During deep circulation, the waters extract heat from reservoir rocks, attaining thermo-chemical equilibrium and rise relatively quickly to the surface, along sub-vertical faults and fractures, preserving part of their physical and chemical characteristics (Vespasiano et al., 2014).Water chemistry was discussed by means of the triangular diagrams among major anionic/cationic constituents and correlation plots. Triangular diagrams show a Na-Cl composition characterized by high bacterial sulfate reduction. Correlation diagrams attest a high calcite and silica precipitation (likely scaling effect) and show a 1:1 ratio between sodium and chlorine that underline an interaction with halite. This represents only a preliminary study that demonstrates the importance of the geochemical characterization as powerful tool to improve the knowledge of natural environment and to predict and avoid problems linked to the study of thermal sites (Gurrieri et al., 1984; Duchi et al., 1991; Italiano et al., 2010).

Geochemical modeling as a tool to investigate the release and fate of Cr in the ophiolitic aquifers of Northern Calabria (S-Italy)

The study of the weathering process of ophiolitic rocks represents an important process due the high toxicity of Cr(VI) with environmental and social consequences and health effects.Since this topic is not well understood, a preliminary study on the release of Cr and other constituents during the weathering of the meta-ophiolitic rocks outcropping in Northern Calabria (Fuscaldo zone) has been carried out using the reaction path modeling.In this work, the EQ3/6 software package, version 8.0 was used together with its data0.ymp.R5 thermodynamic database (Apollaro et al., 2013a, b), upon acquisition of the necessary information such as the stability constants of the aqueous complexes of Cr(VI).Preliminary results showed that the geochemical modeling is an important tool to investigate the phenomena which control the redox state of Cr in near-surface environment and the release and fate of Cr and other chemical constituents in these peculiar environments since during the progressive dissolution of the considered lithotypes, the aqueous solution may attain saturation with respect to different secondary solid phases, potentially acting as sinks of various elements and species.

Occurrence and characterization of asbestos minerals in the area of San Severino Lucano (Basilicata, Southern Italy)

Serpentinites are metamorphic rocks used for building and ornamental purposes since ancient times but they can contain asbestos minerals, thus currently their use is limited or banned in several countries. In this study we have investigated the possible presence of asbestos contained in the serpentinitic rocks outcropping near San Severino Lucano (Basilicata, Southern-Italy). Serpentinites have been characterized in detail combining different analytical techniques in order to detect asbestos minerals that maybe potentially harmful for human health.

Water-rock interaction in the ophiolitic aquifers of Northern Calabria

In this study, data acquired on local rocks, minerals, and shallow groundwaters were used to reconstruct the irreversible rock-to-water mass exchanges occurring during weathering of metabasalts and serpentinites of Northern Calabria, by means of reaction path modeling and taking into account the dissolution kinetics of relevant mineral phases. Groundwater analyses were performed on 69 spring waters and showed a prevalence of Ca–HCO3 over Mg–HCO3 compositions suggesting that groundwaters interact chiefly with metabasalts and secondarily with serpentinites.