1,721,003 research outputs found
Microplastic pollution in show cave sediments: First evidence and detection technique
Full text linkMicroplastic particles are a global problem, which has been widely found in marine and terrestrial environments. However, microplastic pollution in caves and karst aquifers is still poorly studied. To improve the current knowledge of microplastic pollution, we investigated the sediments of a show cave in Italy. We developed a methodology based on a cave-adapted version of the methods used in several studies to detect microplastics from sediments of different environments and with various laboratory tests. The microplastics were extracted from sediments via density separation and subjected to organic matter removal. Filters were observed with and without UV light under a microscope, before and after organic matter removal, and the microplastics were characterised according to shape, colour, and size, with visual identification. About 55% of the fibres observed under the microscope on filters were removed via organic matter removal. An average of 4390 items/kg dry weight was calculated for the touristic zone and 1600 items/kg dry weight for the speleological/research section. Fibre (84.9%) was the most abundant shape, and most microplastics were smaller than 1 mm, accounting for 85.4%, of which 58.4% were shorter than 0.5 mm. The highest microplastic abundance was fluorescent under UV light (87.7%); however, 12.3% of the microplastics observed on filters were not fluorescent. Most fluorescent fibres were transparent (84%), whereas blue (46.1%) and black (22.4%) fibres were more common for the non-fluorescent ones. Our results highlight the presence of microplastics in show caves, and we provide a valid non-invasive and non-expensive analytical technique for the preparation and isolation of microplastics from cave sediments, giving useful information for evaluating the environmental risks posed by microplastics in show caves
Italian travertine in building heritage
Full text linkTravertine is one of the most common stone for building construction used in many countries starting from ancient times. It was one of the favorite stones of the Roman empire: the main example is the Colosseum in Rome. All over the world travertine is found in important monuments and in various modern structures: for example, the Conservation Center of the J. Paul Getty museum in Los Angeles and Jiangsu Provincial Art Museum in Nanjing, China and it is very appreciated and requested in the construction of recent thermal bath. In addition to Italian travertine, the other famous types of this stone are known throughout Europe (i.e. Germany, Hungary) and Asia (i.e. Turkey, China, Iran).
Travertine is considered a durable stone despite the weathering caused by air pollution. It is observed in urban areas that the facades may be covered with a black crust where gypsum and calcite are the main minerals .
Nine different types of travertine coming from Tuscany and Umbria (Italy) have been investigated. Petrographic analysis, physical mechanical and artificial ageing test have been performed.
Among the different kind of travertine different texture can be identified as: not laminated, laminated: laminated with sub parallel sheets, laminated with concentric sheets. The various travertine depositional structures have been in compared to the different answer to artificial ageing. Finally, it can be asserted that the durability is not connected only with porosity and the analysis of the complex texture of this kind of stone cannot give a simple solution related to its durability
The mechanical resistance of saturated stones
No full textThis paper aims at investigating the effect of the presence of water on the mechanical resistance of stones. The presence of water, connected to the intrinsic properties of the stone (mineralogical composition, fabric, texture, etc.) and to the conditions of use (anchoring systems, climatic parameters, etc ), is the main cause of stone decay. However, the presence of water alone inside stone could cause a decrease in mechanical resistance . The obtained data could in fact be useful to correct the safety coefficient and should be taken into account in the planning of structural stonework. Moreover, useful suggestions can be drawn for the in situ monitoring, taking into account that non destructive tests, together with conventional mechanical methods, are influenced by the presence of water in stones and should be corrected. Three kinds of stones, which have historically been used for structural purposes, have been studied: Pietra di Luserna (gneiss, Piedmont, Italy), Pietra Verde Argento (gneiss, Piedmont, Italy) and Pietra di Courtil (mica-schist, Aosta Valley, Italy). The flexural strength, rupture energy, open porosity and ultrasonic pulse velocity (UPV) have been determined on specimens in dried and saturated conditions at different accelerated ageing steps. As far as the UPV test is concerned, its results are well correlated with the flexural strength values but, without other parameters, it cannot give information on whether the specimen is filled with water, therefore suitable procedures to correct the UPV value obtained in situ are suggested. Destructive methods, and in particular the flexural strength method, instead, give lower resistance values for saturated specimens than dried ones, thus confirming the weakness of the stone due to the water insid
The invisible environmental impact of tourism in show caves: microplastic pollution in three Italian show caves
Full text linkShow caves are the most important geological heritage in the world, a significant economic resource and unique ecosystems characterized by speleothems, particular species and important drinking water reserves, however, microplastic (MP) pollution in caves is poorly studied. The deposits of three NW Italian show caves were investigated: for each cave, six sediment samples were collected along the tourist paths and one in a non-touristic area. MPs were identified and characterized using MUPL automated software, observed with and without UV light under a microscope, and verified under μFTIR-ATR. MPs were present in sediments of all examined caves: an average of 4300 MPs/kg were found along the tourist paths and of 2570 MPs/kg in the speleological zones. MPs less than 1 mm, fibre-shaped, polyesters and polyolefins dominated the samples suggesting that synthetic clothes are the main source of pollution in show caves. Our results highlight a high pollution of MPs in the examined show caves, despite the different touristic and environmental characteristics. The subterranean environment monitoring gives useful information to assess risks posed by MPs in show caves and consequently define strategies for the conservation and management of caves and natural resources
Monitoring of lampenflora growth on speleothems exposed to LED lights in show caves
Full text linkSpeleothems, geological formations by mineral deposits that accumulate over time, are the major show caves attractions. However, they are often subjected to alterations linked to tourism, including the so-called lampenflora. Lampenflora is a community of photosynthetic microorganisms, mainly diatoms, cyanobacteria, and green algae, which sometimes also include mosses, ferns and higher plants, carried into the cave by tourists, water, gravity, air circulation and animals.
Lampenflora development on speleothems in show caves is due to the installation of artificial lights, which allow the photosynthetic activity in an otherwise dark environment. The lampenflora growth causes physico-chemical and aesthetic damage to speleothems, and changes the subterranean ecosystem modifying the food chain and damaging the autochthonous organisms. Moreover, microorganisms activities can release acid substances that lead to the deterioration of the formations surface.
Although in recent years lampenflora presence has been increasingly monitored in show caves from a biological point of view, geological modifications on surface of speleothems are less studied, such as the impact of the new LED lamps. This work aimed to give operational indications after two-year of sutdies to verify lampenflora growth after the installation of LED lights systems, and evaluate changes in calcite crystal habits over time, due to lampenflora growing. Homogeneous speleothems slabs without lampenflora were used for the test, as natural substrate, totally compatible with the formations in the examined cavity. Different slabs were positioned in several points of the cave along the tourist paths, at different distances and angles from the LED lamps. In this work, first results applied to Bossea cave, Italy, were reported such as example of application of this protocol. The results of this preliminary study can be the starting point for future and more complete monitoring in show caves, useful for the protection of the geological and environmental heritages
A research to study the unstoppable subterranean journey of microplastics
Full text linkMicroplastics (MPs) are a global problem, contaminating remote areas too. However, different environments are poorly studied, such as subterranean ones and karst areas, despite the global drinking water sources and the environmental heritages. MPs can endanger the fragile subterranean ecosystems, be consumed or assimilated by animals, damage speleothems, and pollute karst aquifers.
The aim of this multidisciplinary research is to investigate MP pollution in waters and sediments in karst surface and subterranean environments from a geological, biological and environmental point of view, in order to monitor the state of ecosystems.
Samples from different European karst areas were collected and investigated, from show caves to unexplored caves, from surface watercourses to groundwaters. The sediments of three Italian show caves (Bossea, Borgio Verezzi and Toirano caves, Piedmont and Liguria. Italy) were analyzed, highlighting the presence of high amount of MPs along tourist paths and in speleological areas. Surface and subterranean waters of Bossea karst system showed MP pollution in all examined samples, underlining the importance of the entire aquifer karst systems monitoring, even susceptible to contamination by surface pollutants. Different protected aquatic surface (spring) and subterranean (caves) environments of the Classical Karst were analyzed in order to verify micropollution in habitats hosting particularly protected species such as the olm Proteus anguinus. All samples highlighted high values of MPs and anthropogenic microfibers. Sediment samples in not jet explored caves of Abruzzo region, Italy, were collected to verify MPs pollution even in underground environments not directly affected by human presence, showing still little threatened habitats by MP pollution. Samples from different caves in Herzegovina and Slovenia, and from Italian springs with different karst characterizations will be analyzed too, in order to understand MP transport in active karst systems and deposition in vadose zones. Other micropollutants linked to MPs will be analyzed too. Alongside, specialized hypogean crustaceans from Bossea karst system were analyzed in order to understand micropollutants ingestion even in subterranean habitats (Sforzi et al., 2024).
Karst areas and caves are one of the most important and well-known geological features in the world, fragile and unique ecosystems with an exceptional scientific, cultural and environmental value, as well as an important economic resource. Monitoring of these environments is fundamental for their conservation and to propose new strategies for the protection and conservation of karst habitats.
Sforzi L. et al. (2021) - (Micro-)Plastics in Saturated and Unsaturated Groundwater Bodies: First Evidence of Presence in Groundwater Fauna and Habitats. Sustainability, 2024, 16(6), 2532, https://doi.org/10.3390/su1606253
Itria Valley (Apulia, Italy): Comparison of limestones for the construction and restoration of “Trulli” roofing
Full text linkThe high concentration and cultural relevance of dry-built constructions in a territory such as Itria Valley, in Apulia (southern Italy), which was designated a World Heritage Site by UNESCO in 1996, make such constructions especially valuable, and raise the matter of conservation through the accurate selection and treatment of natural stone materials. The original and traditional way of construction (more precisely, the roofing of trulli) relies on the use of flat stones, ‘chiancarelle’, which are commonly taken from local accumulations (‘specchie’) or quarried from shallow embankments. Recently, the trend has shifted towards the use of sawn stones, which are less expensive since they do not need to be shaped by artisans. The scope of this study is to compare the mechanical performance of chiancarelle and sawn stones, to find whether correlation trends can be found between the technological properties of such stones, and to assess whether ageing cycles can produce variations in the mechanical behaviour of sawn stones. Finally, the results obtained allow the identification of the tested material and its geological origin, as well as the correlation with mechanical and technological properties
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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