Sinkholes and land subsidence are among the main coastal geologic hazards. Their occurrence poses a serious threat to the man-made environment, due to the increasing density of population, pipelines ...and other infrastructures along the coasts, and to the catastrophic nature of the phenomena, which generally occur without any premonitory signs. To assess the potential danger from sinkholes along the coast, it is important to identify and monitor the main factors contributing to the process. This article reports a methodology based on sequential stratigraphic, hydrogeological and geophysical investigations to draw up a susceptibility map of sinkholes in coastal areas. The town of Casalabate situated in the Apulia region (southern Italy), affected by a long history of sinkhole phenomena, is here presented as an example. The approach proposed is based on sequential stratigraphical, geomorphological and geophysical surveys to identify the mechanisms of sinkhole formation and to provide a zonation of the areas in which further sinkhole phenomena may likely occur. Interpretation of the ground penetration radar and electrical tomography profiles has enabled us to identify the potentially most unstable sectors, significantly improving the assessment of the sinkhole susceptibility in the area. The proposed methodology is suitable to be exported in other coastal areas where limestone bedrock is not directly exposed at the surface, but covered by a variable thickness of recent deposits.
A PM1 geochemical and mineralogical study using Scanning Electron Microscopy (SEM) was performed on a pilot site in the Agri Valley which is close to the oil pre-treatment plant (C.O.V.A) of Europe's ...largest on-shore hydrocarbon reservoir. The study identified PM1 geochemical and mineralogical characters in the period before, during and immediately after a burning torch flare event. The finer fraction (DFe < 0.7 µm) consisted mainly of secondary particles and soot. In the coarser fraction (DFe≥0.7 µm), natural particles originating from crustal erosion and soot were abundant. Fine quartz particles and lower Al / Si ratios are markers for desert dust origin, proving that a Saharan dust episode which occurred during the observation period played a significant role in supplying geogenic aerosol components to the PM1. Largest amounts of ≥ 0.7 µm fraction particles observed on the day of flare event may be due to a greater supply of Saharan geogenic particles. Soot had been significantly increasing long before the flare event, suggesting that this increase is also related to other causes, although we cannot exclude a contribution from flaring. S-rich aerosol consisted mainly of mixed particles originating from deposition and heterogeneous nucleation of secondary sulfates on mineral dust. Only-S particles were identified in the ≥ 0.7 µm fraction following the flare event. These particles may be indicators of larger amounts of sulphur in the atmosphere.
This paper focuses on the impacts of contemporary geomorphological processes on fruition activities in a karst area of Salento (Apulia, southeastern Italy). The work illustrates the results of ...studies in a sinkhole field at Nociglia, in the Lecce province, recently recognized as a geosite and where shallow phreatic speleogenesis operates close to the water table level with the formation of karst caves, successive roof collapse, formation of wide caverns, and sinkhole development at the surface. All these features threaten the nearby infrastructures including a province road. Salento has a great number of active sinkholes related to natural and anthropogenic cavities. Their presence is at the origin of several problems in the built-up environment, due to increasing population growth and development pressures. In such a context, the detection of cavities, and the assessment of sinkhole hazards present numerous difficulties. To assess the potential danger from sinkholes, it is important to identify and monitor the main factors contributing to the formation process. A multi-disciplinary approach, comprising geological, geomorphological, and geophysical analyses, is necessary to obtain a comprehensive knowledge of these complex phenomena in karst areas. Geophysical methods can be of great help to monitor the processes and for identifying and mapping features related to the underground voids, by detecting contrasts in physical properties, such as density and electrical resistivity, with the surrounding sediments. At the same time, recognition of the presence of sinkholes by geophysical methods has to adapt to the local geological conditions and take advantage of the integration of the several methodologies available. The territory of Nociglia demonstrates that monitoring is essential for the safe exploitation of these type of geomorphosites.
This work presents a novel approach to comparing and graphically representing simultaneous concentration measurements of PM10, PM2.5 and PM1 (i.e., aerosol particles with aerodynamic diameters less ...than 10, 2.5 and 1 μm, respectively) with similar data reported in the literature using PM2.5/PM10 and PM1/PM10 concentration ratios. With this aim, a dedicated triangular diagram was used. The proposed approach was applied to size-segregated particulate matter (PM) concentrations recorded in the Agri Valley (Basilicata region – southern Italy). Results show that the PM10, PM2.5 and PM1 concentrations recorded in the Agri Valley are comparable both in terms of PM concentration ratios and PM levels to an urban site.
Weathering of outcrops of ultramafic rocks (remnants of ancient oceanic crust) is a source of biologically toxic trace elements, particularly first row transition elements. The Cr and Ni ...concentrations of serpentinite and metabasite outcrops in the northern sector of the Pollino massif (Lucanian Apennines, southern Italy) are hundreds of orders of magnitude higher than those of the upper continental crust. In this region, exposed intermediate to lower crustal rocks are significantly enriched in Ni, Cr, and V relative to the average upper continental crust. We evaluate the levels and distributions of trace elements of environmental concern, including Cr (as total dissolved Cr and Cr(VI)), V, Mn, Fe, Ni, Cu, Zn, As, Pb, and U, in spring waters from the northern sector of the Pollino massif.
The major solutes in the spring waters from this region are Mg-HCO3 and Ca-HCO3. The Mg-HCO3 type waters are produced mainly through the interaction of meteoric waters with serpentinites, whereas the Ca-HCO3 type waters are produced through the interaction of meteoric waters with Ca-rich rocks (i.e., carbonate rocks, calc-schists, and metabasites). Thermodynamic evaluation indicates that in the MgO–SiO2–Al2O3–H2O system, waters flowing in serpentinites fall in the kaolinite field, close to the kaolinite–Mg-vermiculite phase boundary. This result arises because kaolinite is a relatively early reaction product, which is consumed to produce Mg-vermiculite and further Mg-saponite. In the CaO–SiO2–Al2O3–H2O system, Ca-HCO3 type waters fall either in the field of gibbsite or kaolinite, depending on dissolved silica.
Chromium (VI) contamination associated with local mineralogy and with maximum admissible concentration >5μgL−1 was observed for nine springs (both Mg-HCO3 and Ca-HCO3 type waters). The Cr(VI)-rich Ca-HCO3 springs are not located in serpentinites. However, some of these waters likely acquire their high Cr levels from interacting with serpentinite clasts, as in the case of springs flowing through conglomerates. In addition, Cr(VI) contamination is not limited to waters interacting with serpentinites or serpentinite clasts, because in one case weathering of garnet-rich gneiss is responsible for the release of significant amounts of Cr(VI) in solution.
Finally, studies are needed to address the potential health risks associated with the observed high concentrations of Cr(VI) in waters from the Pollino massif area. A mode-of-action analysis is needed to evaluate adverse health risks associated with exposure to Cr(VI) in drinking water, especially as Cr contamination is not limited to springs flowing through serpentinites.
► Serpentinite, metabasite, and garnet-rich gneiss in the Pollino massif, Italy. ► Distributions of Cr(VI) in spring waters. ► Springs waters in the Pollino massif are either Mg-HCO3 or Ca-HCO3. ► Cr(VI) contamination in springs of both Mg-HCO3 and Ca-HCO3 type. ► Contamination is not confined to springs which flow through serpentinites.
Silty sands and clayey silts taken from a landslide in the Agri Valley have been analysed in order to study the role of sediment composition in the slope stability and the development of a slip zone. ...A geognostic hole was used to collect samples and monitor movements. A slip zone at a depth of about 14 m was identified. Compositional and physical–mechanical characterisation of samples was carried out. Some compositional characters, such as a 32–2 μm grain-size fraction, clay mineral content, cation exchange capacity and total nitrogen, increase in the slip zone. Some correlations have been found between geotechnical properties (residual shear strength and residual friction angle) and the same compositional characters, which can therefore be considered possible factors influencing slope stability.
A landslide, to the west of Montemurro (a small village in southern Italy), has recently caused damage to buildings and other infrastructure in an urbanized area; as a result the development of new ...economic activities has been prohibited. The landslide phenomenon started in the last century and has been studied since the 1990s using classical geotechnical methods; however the sliding body continues to move. This paper presents the results of a study carried out using field surveys, geognostic investigations and TDR (time domain reflectometry) measurements in order to reconstruct the stratigraphy of the sediments involved and to further understand the geological and geomorphological context of the slope. This study is part of a larger multidisciplinary project, the results of which will also be presented in this paper. The landslide (rotational slide in the upper sector, developing into a translational slide in the lower part) affects Quaternary continental clastic deposits resting on a bedrock formed by Tertiary siliciclastic sediments of the Gorgoglione Flysch. TDR measurements did not show any significant movement during the period monitored (January 2013–January 2014). Slip zone geometries were hypothesized using inclinometric measurements taken from previous studies, stratigraphic data and geomorphological interpretations of topographic scarps. Feedback from monitoring will confirm this hypothesis.
This study investigated in detail the mineralogical changes within 8 little maturation ponds filled with different clay materials placed in a spa center in southern Italy and kept under the ...traditional environmental conditions used by the spa itself. Both short- and long-term maturation periods were investigated.
Several changes were observed in all the samples during the first month of maturation and also in the following 2
months. A significant increase in soluble Na occurred in all the samples. No significant variations in the initial mineral assemblage were detectable either in the bulk material and or in the clay fraction except for the crystallization of neoformed Na-minerals. The amount and the type of silicate minerals did not change in time, but the position and the width of the basal reflection of expansible minerals changed due to a gradual incorporation of new ions into the interlayer space. During the first month a variation in the grain-size distribution as well as a decrease in calcareous nannofossils can be observed. A slight increase in Corg was also recorded during the maturation.
Some of the parameters which were more sensitive to short maturation continued to adjust also during a fairly longer time such as 15
months. The spacing and the FWHM of the basal reflection of smectite and mixed layers minerals and the crystallization of soluble salts were good monitors of long-term maturation.
There were two tracks in the maturation period and were related to particular indicators.
Typical indicators of this “first track”, mainly between months 1 and 2 of maturation were the grain size, the calcareous nannofossils and the amount and the type of exchangeable cations. The salt crystallization can be considered a suitable indication of the “second track” of maturation within 6–9
months.
►Most of the effect of maturation in the studied samples has been attributed to water–rock interaction. ►There are two tracks in the maturation period and are related to particular indicators. ►Typical indicators of this “first track”, mainly between months 1 and 2 of maturation are the grain size, calcareous nannofossils and the amount and the type of exchangeable cations. ►The salt crystallization can be considered a suitable indication of the “second track” of maturation within 6–9
months.
The main factors affecting environmental sensitivity to degradation are soil, vegetation, climate and management, through either their intrinsic characteristics or by their interaction on the ...landscape. Different levels of degradation risks may be observed in response to particular combinations of the aforementioned factors. For instance, the combination of inappropriate management practices and intrinsically weak soil conditions will result in a severe degradation of the environment, while the combination of the same type of management with better soil conditions may lead to negligible degradation.The aim of this study was to identify factors and their impact on land degradation processes in three areas of the Basilicata region (southern Italy) using a procedure that couples environmental indices, GIS and crop-soil simulation models. Areas prone to desertification were first identified using the Environmental Sensitive Areas (ESA) procedure. An analysis for identifying the weight that each of the contributing factor (climate, soil, vegetation, management) had on the ESA was carried out using GIS techniques. The SALUS model was successfully executed to identify the management practices that could lead to better soil conditions to enhance land use sustainability. The best management practices were found to be those that minimized soil disturbance and increased soil organic carbon. Two alternative scenarios with improved soil quality and subsequently improving soil water holding capacity were used as mitigation measures. The ESA were recalculated and the effects of the mitigation measures suggested by the model were assessed. The new ESA showed a significant reduction on land degradation.
The Salento coal deposits (south-eastern Italy) are unutilized because these deposits are thin and nearly uneconomic but they have a high scientific and economic value due to their high organic ...sulphur content. The studied area is located in the western Salento peninsula where wells used by a fish-farm (“Ittica Ugento”) have shown high concentrations of hydrogen sulphide. Data from surface and boreholes stratigraphic surveys integrated with electrical resistivity tomography (ERT) allow us to define the structure, depths and geometry of the aquifer and its relationship with saltwater intrusion. Induced polarization (IP) with pole–dipole array survey has been carried out near the coastline. The value measured was over 50 msec. A direct relationship is shown to exist between IP values and the aquifer containing sulphur water. The high resolution of the data obtained with the applied methods not only shows the validity of the methodology but is the key to evaluating the groundwater resources of the area. The proposed mechanism is that of entrapment of sulphur water in a graben structure: when sulphate-enriched waters of marine origin come into contact with organic substances and lignite deposits (Galatone Formation, Oligocene), they are deprived not only of free oxygen, but also generate hydrogen sulphide as a result of the reduction of sulphates.
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