United States

The Siele mine and its smelting plant are part of the world class Monte Amiata mining district (MAMD – Tuscany, Italy). The mine is located close to the Siele creek (c.), which drains the mining area, then flows to the Paglia River (R.), which in turn is an affluent of Tiber River, flowing through the city of Rome to the Mediterranean Sea. After closure in 1981, the mining area was subjected to the first reclamation in the district (and at the worldwide scale), completed in 2001. In this study, we present new data on Hg concentrations in soils, stream sediments, and air in the Siele mining area and along the Siele c., and we review all previously available data, with the aim of quantifying the Hg contribution from the Siele c. into the Paglia R., and of documenting the evolution of the system following mine reclamation. Hg concentrations (up to 5400 mg/kg) in stream sediments are comparable to pre-reclamation values in the first 500 m downstream the mine site. They decrease downstream to the confluence with the Paglia R., but remain anomalous (i.e., above the 1 mg/kg Italian law limit for residential soil). Comparison of pre- and post-remediation data of gaseous elemental mercury (GEM) in air shows that Hg0 emissions in most of the sites within the Siele mining area are lower than pre-reclamation values, but in few outdoor sites, levels are still high (up to 9500 ng/m3), exceeding the existing regulatory limits (“Norma Amiata”: 300 ng/m3 in outdoor sites). On the other hand, Hg mobility, determined by leaching tests, is mostly below the limits defined by pending regulations (1 μg/L), and methyl-Hg concentrations are mostly below 1 ng/kg (with a single value of 6 ng/kg). Results show the Siele c. plays a role by no means negligible in the general picture of the contributions of Hg in the Paglia R. basin, proving to be one of the most critical areas of the entire MAMD. Indeed, concentrations of Hg in sediments and soils in the Siele c. are comparable to those of the Pagliola c., draining the Abbadia S.S. mine (the main site of the MAMD), where reclamation is still under way. Moreover, despite remediation works, Hg emissions from contaminated soil will represent a significant contribution to the atmospheric load of Hg in the future, if no further remediation action is taken. The Siele system has a low resilience and natural recovery will take many years (probably decades), during which the area will remain an important source of Hg for the Paglia and Tiber River systems, and eventually for the Mediterranean Sea. This study provides important background data for local authorities to implement monitoring strategies and find new remediation plans based on the identified critical area. Further, at a global scale, this work contributes additional data to the assessment of the global Hg budget to the atmosphere and the hydrosphere.

SGI 2021

Low resilience of a mercury mining area after reclamation: the case of the Siele mine (Mt. Amiata Mining District, Italy)

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L'Istituto Nazionale di Oceanografia e Geofisica Sperimentale - OGS e il Dipartimento di Matematica e Geoscienze dell'Università di Trieste sono orgogliosi di ospitare il 90° Congresso della Società Geologica Italiana a Trieste dal 14 al 16 settembre 2021. La modalità del congresso è interamente online.

Con il motto "Geologia senza frontiere" questo evento mira a promuovere le Scienze della Terra come disciplina scientifica proiettata nel futuro, oltre i confini geografici, politici e disciplinari, per comprendere meglio l'interno del Pianeta Terra e la struttura del sottosuolo, difendere la società da pericolosi eventi geologici, comprendere meglio la variabilità climatica, pianificare l'utilizzo delle georisorse in modo etico e nel rispetto dell'ambiente.


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The National Institute of Oceanography and Experimental Geophysics - OGS and the Department of Mathematics and Geosciences of the University of Trieste are proud to host the 90th Congress of the Italian Geological Society in Trieste on 14-16 September 2021.  The Congress will be held entirely online.

With the motto "Geology Without Borders" this event aims to promote Earth Sciences as a scientific discipline projected into the future, beyond geographical, political and disciplinary boundaries, to better understand the interior of Planet Earth and the structure of the subsurface, defend society from dangerous geological events, better understand climatic variability, plan the use of geo-resources in an ethical way and respecting the environment.


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Earth Sciences should be understood not only as necessary for a better understanding of the interior of the planet Earth, but also as a defense of society from dangerous geological events, for the understanding of climatic variations, for the planning and use of georesources in a ethical and respecting and protecting the environment.

poster

On 11 and 12 October 2018, Sardinia was hit by exceptional meteorological events that particularly affected the south-eastern area, in the Sarrabus, and in particular various road infrastructures under the responsibility of the Province of Southern Sardinia. The administrative procedure of the interventions originated from the Resolution of the Council of Ministers of 8 November 2018 which declared a state of national natural disaster. Subsequently, the Ordinance of the Head of the Civil Protection Department n ° 558 of 15 November 2018 was issued, which allowed the first management activities to be started for the planning of the first interventions, the rescue and assistance to the population and the restoration of functionalities of infrastructures affected by adverse phenomena. The Province, following an inspections carried out by the geologists and the engineers of the Traffic Service, identified 9 intervention areas, particularly affected by flood events. Among these, the one in correspondence with the bridge of the Camisa locality, at Km 23 + 250 of the provincial road n ° 20, was particularly critical. The procedures for safeguarding public safety and the structure concerned were immediately activated, in conjunction with the Prefecture, the Regional Civil Protection and the municipalities concerned. The temporary interruption of the road was arranged, which at the "Ponte Camisa" was bypassed by the large flow rates of the Rio Corr'e Pruna. The bridge was affected by an exceptional flood which led to the removal of a large part of the road foundation, embankments and escarpments. In the following days an initial census was made of the serious damage caused, which led to interruptions in the road network, narrowing of the carriageway and considerable risk conditions for public safety. An estimate of the damage was made and the request for funding was forwarded to the Civil Protection of the Sardinia Region. This estimate concerned the restoration of the work of art and the complete functional recovery and safety of the road artery. The works to be designed also include the verification of the residual functionality of the bridge in the riverbed, the previously installed gabions and the geological and hydraulic study of the erosive phenomena that have occurred. Following the granting of the requested funding, the restoration work was contracted out, the artifacts were rebuilt, the embankment works and the river bed were strengthened and restructured, able to better withstand any new calamitous events. Appropriate management procedures for the work were therefore provided in the event of an alert of adverse weather conditions. A first study was therefore carried out aimed at reducing the persistent risk on the area, for which the request for funding for the execution of the mitigation of the danger parameters of the area is being investigated.

Civil protection interventions - OCDPC n. 558 of 15.11.2018 - Functional recovery of the Provincial Road No. 20 - Municipality of Castiadas (Sardinia)

On 11 and 12 October 2018, Sardinia was hit by exceptional meteorological events that particularly affected the south-eastern area, in the Sarrabus, and in particular various road infrastructures under the responsibility of the Province of Southern Sardinia. The administrative procedure of the interventions originated from the Resolution of the Council of Ministers of 8 November 2018 which declared a state of national natural disaster. Subsequently, the Ordinance of the Head of the Civil Protection Department n ° 558 of 15 November 2018 was issued, which allowed the first management activities to be started for the planning of the first interventions, the rescue and assistance to the population and the restoration of functionalities. infrastructures affected by adverse phenomena. The Province, following an inspection carried out by the geologists and engineers of the Traffic Service, identified 9 intervention areas, particularly affected by flood events. The situation of the provincial road No. 97 was particularly critical, with seven road sections affected by erosive phenomena and a great state of alteration caused by the considerable outflows that occurred during the calamitous event. The procedures for safeguarding public safety and the structure concerned were immediately activated, in conjunction with the Prefecture, the Regional Civil Protection and the municipalities concerned. Various roadway narrowings have been prepared due to strong erosion phenomena which have led to a great increase in the danger to road users. The main hydro-geomorphological erosion phenomena concerned: - at Km 2 + 600, erosion of the embankment of the road embankment on the progressive right, for about 40 meters and a height of 2.5 meters, failure of the guard rail, anomalous accumulation of materials in the docks; - at Km 3 + 200, burying of the gutter for a length of 20 meters and of a “road manhole” crossing infrastructure; - at Km 3 + 850, strong erosion of the escarpment on the right side for about 75 meters in length and for heights ranging from 1 meter to 2.5 meters in height; failure of the guard rails on both sides of the road; - at Km 4 + 300, erosion of the right escarpment for a length of 16 meters and a depth of 1 meter and consequent erosion of the gutter, partially present also on the left side; - at Km 4 + 900, erosion of the right escarpment for 23 meters in length and 1 meter depth and consequent erosion of the quay, failure of the guard rail on both sides; - at Km 5 + 200, erosion of the embankment of the right road embankment for 14 meters in length and 1 meter in height, undermining of the crossing infrastructure and damage to underground services, failure of the guard-rail on the right side, erosion of the left embankment for about 23 meters of length and 1 meter in height, failure of the left guard rail; - at Km 5 + 400, erosion of the left gutter for 25 meters in length; An estimate of the damage was then made and the request for funding was forwarded to the Civil Protection of the Sardinia Region. This estimate concerned the restoration of the entire section of provincial road No. 97, and the complete functional recovery and safety of the road artery, both in shape and along the quays and appurtenances. The works to be designed also provide for the verification of the residual functionality of the bridge in the riverbed, the previously installed gabions and the geological and hydraulic study of the erosive phenomena that have occurred. Following the granting of the requested funding, the restoration work was contracted out, the artifacts were rebuilt, the hydraulic crossing works partially reinforced, able to better withstand any new calamitous events. A first study was therefore carried out aimed at reducing the risk persisting in the area, for which the request for a loan for the implementation of the intervention to mitigate the hazard parameters of the area is in the preliminary phase.

Civil protection interventions - OCDPC n. 558 of 15.11.2018 - Restoration and functional recovery of Provincial Road No. 97 - Municipalities of Castiadas and Muravera

Assessment of the stability of rock masses is crucial in the process of risk mitigation. Among the many factors predisposing the Italian territory to geohazards, it has to be mentioned the geological and geomorphological setting, often characterized by karst processes and widespread presence of cavities, of both natural and anthropogenic origin, potentially leading to sinkholes and other instability mechanisms. For these reasons, the study of rock masses has always been of primary importance, as a primary tool to define the susceptibility to geological instability and to safeguard the environment. To solve the problems related to traditional analyses, in many cases too expensive and difficult to carry out, over the last decade the implementation of new digitalized methods, such as close- and long-range remote sensing techniques, has become essential to quantitatively describe the structural arrangement of rock masses. This necessarily requires robust and reliable methods dedicated to extracting the primitive geometries representing the discontinuities on a rock outcrop. A novel approach, combining observations made in situ with digital results, has been recently proposed (Cardia et al., 2021). This method is able to extract discontinuities clusters in a fully supervised way, thus allowing the user to evaluate every situation by determining specified tolerance angle ranges for both dip/dip direction. We provide here an ongoing development of the method, based on an algorithm that has been implemented in the software GeoDS. The algorithm takes as input a K value, representing a density threshold, from which it will start searching for coplanar points in a given range of 10° for both dip and dip direction, and a seed range value, that is the number of sample points that the system chooses randomly to evaluate each cluster. The greater this value is set, the more successful is going to be the result; however, this comes with a computation time cost, which extent depends on the computer capability. This new algorithm, called IPDE (Iterative Pole Density Estimation) is then coupled with a KDE (Kernel Density Estimation), extremely useful to plot the graphic projection, on which the user can choose to manually select points or to evaluate the sets with two different automatic clustering techniques, K-means and Gaussian Mixture. The proposed method aims to improve the evaluation of discontinuities on a rock outcrop in a new and original way.

The Iterative Pole Density Estimation, a new approach to assessing the stability of rock masses from 3D point clouds

An increasing number of heavy precipitation events causing flash floods, debris flows and other types of landslides, as well as severe morphological effects on changes have affected Italy and Europe over the last years (Tarolli et al., 2012).  Italian territory is particularly prone to these types of phenomena, due to a combination of distinctive topographic and meteorological characteristics (Rinaldi et al., 2016). Extreme events induce physical impacts on rivers and valley bottoms, consisting in channel widening (due to bank erosion and overbank deposition), changes in bed level, avulsions, huge amount of sediment transport, as well as recruitment of large wood. On overall, channel widening is the dominant geomorphic effect observed in many rivers. If on one hand channel widening represents an essential process to sustain channel morphology and fluvial ecosystems, on the other hand, in highly populated fluvial corridors, it can result in the loss of agricultural land and damages to buildings and infrastructures; thus, it should be considered a natural hazard and a major management problem. Interests in geomorphic effects of large floods have been intensively increasing over the recent decades. At Italian level, several case study papers were published, and new integrated approaches were proposed (Rinaldi et al., 2016). Even, the Italian Istituto Superiore per la Protezione e la Ricerca Ambientale (ISPRA) have proposed a method (the Event Dynamics Classification - EDC, Rinaldi et al., 2015) which provides tools to predict the geomorphic flood hazards, and supports the definition of morphological river corridors, meant to be complementary to inundation maps determined by “classical” hydraulic modelling. In light of this, an overview of recent studies on flood events at Italian level is presented, with the aims to highlight similar trends in channels changes induced by large floods and to assess the relative role of the different hydrological and morphological factors controlling the flood geomorphic effectiveness.

Geomorphic effects of large floods: some examples from Italian rivers

Sediment transfer in mountain streams occurs via processes classified as debris flows, debris floods, and water flows. The analysis of the sediment-water flows occurring during high-magnitude floods is currently a scarcely explored issue. This knowledge gap is particularly striking for the debris floods, a water-driven flood flow with extremely high bedload transport that has been rarely investigated. This study investigates how the transport mechanisms activated in a mountain stream during a high-magnitude flood differ from those triggered during ordinary floods, focusing on the controlling factors and conditions required for debris flood occurrence. The study area is the Tegnas catchment (drainage area 51 km2), a mountain basin of the Dolomites (northeastern Italy) affected in October 2018 by a severe flood (Vaia Storm), whose recurrence interval has been estimated to approximately 200 years. We developed a post-flood survey protocol for distinguishing various flow types based on the features of the flood deposits. The transport processes typifying the stream network during ordinary floods and those occurred during the Vaia Storm were determined through the field survey of the deposits. We observed water flow as a response to ordinary events occurring along the entire Tegnas main stem. During the Vaia Storm, water flow still dominated, although debris floods were documented at several sub-reaches. The unit stream power induced by the Vaia Storm was calculated based on the peak discharge computed at the sub-reach scale using a rainfall-runoff model, and channel widening was determined measuring the pre- and post-Vaia channel width. The comparison between the high-magnitude and the ordinary flows allowed us to infer the existence of relationships between the transport mechanisms, the hydraulic forcing, and channel dynamics. The upheaval of the ordinary flow types did not occur along the entire stream network: water flows transitioned into debris floods only under unit stream powers exceeding the threshold of 5500 Wm–2 or downstream of sediment-injection sites. Debris floods occurrence appears to be facilitated by tributaries prone to debris flow and connected to the receiving stream, the injection of fine material into the flows (which can occur as consequence of channel-bank erosion or overbank floodwater re-entering the channel), and channels characterized by high slope and relative narrow section. The occurrence of debris floods caused higher channel widening than that induced by water flows. The complex relationships found between flow types and a range of controlling factors reveal that a detailed characterization that includes field observations is necessary to understand the transport mechanisms that can affect a specific channel site during high-magnitude hydrological events for an accurate and reliable definition of flood hazard at the local (e.g., sub-reach) scale.

Debris floods in mountain streams: Insights from the Vaia Storm (October 2018) in the Tegnas catchment (Dolomites, Italy)

Several heavy precipitation events causing flash floods, debris flows, landslides, and morphological channel changes have occurred in Europe over the last years. In mountain environments, mass movements along the hillslopes are important sources of sediment supply to the rivers, and may enhance the geomorphic effects of floods. The Stolla creek (catchment area: 40 km2) is a confined/partly confined channel of the Dolomites (Easter Italian Alps), that was affected by an extreme flood in August 2017, and by a moderate flood in August 2020. The geomorphic effects of the two floods were investigated in the main channel and along the hillslopes with the aims: to compare the channel changes induced by the two events; to assess the impacts of the lateral sediment connectivity to the channel response. A multi-methodical approach was applied, including radar rainfall estimation, rainfall-runoff modeling, field surveys, remote sensing, geomorphological and statistical analysis. Hillslope and channel processes were mapped by comparing multitemporal orthophotos and Digital Terrain Models. Debris-flow connectivity to the main channel was derived by combining field evidence and geomorphometric analysis. The 2017 flood was caused by rainfall with a short duration (6 hrs) and a rain rate exceeding 45 mm in one hour. More than 600 debris flows were triggered along the hillslopes, among which 23 were connected to the Stolla. Important discontinuities for the sediment flux were represented by the floodplains. The Stolla channel experienced channel widening occurred through bank erosion, and overbank depositions. With ratio (ratio between the channel width after and before the flood) was between 1.3 and 4.9. Widening was accompanied by channel bed aggradation up to 1.2 m or incision up to -2.2 m. Widening through bank erosion was more common in narrower reaches, affected by higher flood power, and presenting higher connectivity with debris flows. Although 294,000 m3 of sediments were eroded in the connected debris flows and 12,380 m3 were transferred to channel from toe erosion processes, limited volumes of sediments (< 1000 m3) were exported to the catchment outlet. The 2020 flood event was characterized by a lower rain rate (max 17 mm h-1) and a long duration (48 hrs) and did not trigger debris flows. The moderate magnitude of the flood peak did not lead to channel widening, but only bed incision (up to -1.4 m) in the reaches where the 2017 event had caused channel-bed aggradation occurred. 

Catchment response to different severity storm floods: channel variations and hillslope sediment coupling dynamics

The Apuan Alps are a mountain range in northern Tuscany exploited for the famous Carrara marble since the Roman age. The Apuan quarrying district currently comprises about 150 quarries and most of them are located at high elevations. Marble blocks are cut and re-squared by means of line drilling and various sawing techniques, diamond wire and chain saw being the most used. Such quarrying activities produce a fine marble powder that frequently mixes up with meteoric water, producing a slurry that can easily infiltrate into the karst aquifers through solution-enlarged fractures. Depending on the aquifer hydrodynamics, the marble slurry can eventually reach the karst springs, thus contaminating high quality waters generally used for the human consumption. Several samples of marble powder, karst spring deposits, and stream sediments were collected and analyzed for their mineralogical, morphological and sedimentological characterization, to evaluate the degree of pollution of the Apuan karst aquifers. Quarry powder samples are mainly made up of calcite crystals, whereas spring and stream sediment samples have variable proportions of calcite, silicates, and dolomite grains. The clasts from marble powder produced by diamond wire and chain sawing have constant morphological features, whereas the sediments collected in filtering tanks and disposal bags exhibit more heterogeneous characteristics. The quarry powders are generally finer than the sediments, although some overlap occurs probably because of marble powder contamination in the sediments themselves. The most polluted spring samples are characterized by a predominant calcite component that is finer than the silicate one. The same occurs also for the stream samples. Spring samples also show homogeneous morphometric features that are probably related to both marble powder contamination and the transport mechanisms through the karst aquifers. Marble powder pollution appears to be widespread in most of the Apuan karst springs, thus affecting the aquifer hydrodynamics and water quality.

Physical pollution of karst aquifers caused by marble quarrying: the case of the Apuan Alps, Italy

River waters may respond gradually or suddenly to natural or anthropic disturbances by varying their chemical composition. Understanding the nature of these complex interactions plays a crucial role in our fast-changing planet threatened by climatic and human-induced changes. In this work, water chemistry is analyzed as a whole by focusing on its interconnections with hydro-litho-morphologic and anthropic pressures at a basin-wide scale. This implies the introduction of the concept of regime shift, which has been widely applied to study the resilience of ecological systems to environmental perturbations. We propose to transpose this idea to geochemistry by considering Geochemical Regime Shifts (GRSs) as abrupt and permanent changes in the system state (composition) of a given environmental media, triggered by external or inner perturbations (Gozzi et al., 2021). From this perspective, river water composition represents a response variable resulting from the synergic action of environmental drivers and catchment properties. The aim of this study is to detect potential spatial GRSs in the water chemistry of the Tiber River, the third-longest Italian river. To reach this aim potential forcing variables (e.g. land use, terrain slope, human impact and lithology) were considered and estimated for all nested watersheds. Compositional Data Analysis, Robust Principal Component Analysis and score-distance graphs were used to explore data variability and the nature of driver-system state relationships. In the lower reaches, a potential regime shift was identified for major species suddenly changing the water composition from a relative prevalence of N-bearing species to that of Na+ and Cl-. The regime shift scenarios described by Andersen et al. (2008) suggest that the observed shift might represent a threshold-like state response triggered by lithological forcing. Conversely, no abrupt changes were detected for trace elements which instead seem to respond gradually to environmental pressures. The research offers new perspectives for future studies and for a deeper understanding of the circumstances controlling river system’s self-restoring capability.

Detecting Geochemical Regime Shifts in the compositional dynamics of the Tiber River waters (Italy)

Mercury (Hg) contamination in the Gulf of Trieste (GT, northern Adriatic Sea) is due to historical mining activity at Idrija (Slovenia) and still represents an environmental issue of great concern (Covelli et al., 2001; Covelli et al., 2021). Indeed, the freshwater inputs from the Isonzo/Soča River have been identified as the main source of Hg into the GT. At the river mouth, the element was found to be mainly associated with the suspended particulate matter, especially following periods of medium-high river discharge and river plume events in the GT (Covelli et al., 2006; 2007) The primary aim of this research is to evaluate the occurrence and distribution of both dissolved (DHg) and particulate (PHg) Hg along the water column in the northernmost sector of the GT, a shallow and sheltered embayment suitable for the accumulation of fine sediments and contaminants. In order to achieve this objective, sediment and water samples were collected at six sites which were representative of different targets, such as mussel farming and tourism activities. Moreover, different environmental conditions including unperturbed and perturbed hydrological conditions, induced by both natural and anthropogenic factors, were taken into account. The amount of Hg in the surface sediments (0.77–6.39 µg g-1) as well as the relationship between the Hg concentration and the percentage of the 2-16 µm grain size fraction from this study were found to be consistent with previous research focused on the whole Gulf, thus testifying the common origin of the sediment. Results showed a notable variability of DHg (0.07–149 ng L-1) and PHg (0.39–12.5 ng L-1) depending on the interaction between riverine and meteo-marine hydrological conditions at the time of sampling. Mercury was found to be mainly partitioned in the suspended particles and elevated values of PHg were observed following periods of high discharge from the Isonzo/Soča River confirming that the river discharge may represent an important factor in regulating the amount of PHg in the GT.

Mercury in the water column of the Gulf of Trieste is still an environmental issue: the legacy of the Idrija mine twentyfive years after its closure

The gaseous exchange of mercury (Hg) at the water-air interface represents an important aspect of the biogeochemical cycle of this element in the environment. Particularly at sites impacted by Hg due to anthropogenic activities, evasion can contribute to reduce the amount of this metal in the water column, but also to widen its spreading in the environment due to the long-range atmospheric transport of the element (Driscoll et al., 2013). However, dynamics of gaseous elemental Hg emissions from the water-air interface at Hg contaminated sites are still poorly characterised. In this work, Hg evasion fluxes were monitored by means of a flux chamber coupled with a real-time gaseous Hg analyzer (Lumex RA915M) in 3 freshwater environments characterized by different contamination legacy: the artificial reservoir of Solkan (SK-Slovenia) along the Isonzo River, where Hg contaminated sediments due to cinnabar extraction activities at the Idrija Hg mine have been accumulated since 1984, date of the dam construction; the dock near a chlor-alkali plant at Torviscosa (TR-Italy); the Cavazzo Lake (CV-Italy), chosen as pristine environment with no known Hg sources. At each site, 6 distinct sets of flux measurements were performed at regular time intervals during the diurnal period in 3 different seasons (spring, summer, and autumn). Moreover, the concentrations of dissolved gaseous mercury (DGM) were monitored during the sampling period together with total dissolved Hg, incoming UV radiation and main water physico-chemical parameters. As expected, at all sites the highest Hg fluxes were found in summer, due to higher irradiation, which favours the formation of volatile DGM through photoreduction, and higher water temperatures, which decrease the solubility of Hg. On average, Hg evasion fluxes found in this study were higher than those reported in literature for other background freshwater environments. Surprisingly, Hg fluxes at CV site were comparable to those of the other sites, likely due to re-emission of Hg of atmospheric origin, but further research is needed to confirm this hypothesis. The widest diurnal variability of Hg fluxes was observed at TR site, located inside an industrial complex, and likely related to irregular supplies of Hg through atmospheric depositions and water circulation. Conversely, SK and CV showed a more regular trend, confirming that Hg fluxes are strongly influenced by local conditions and site-specific interaction of different factors. Based on these results, the investigated sites can be considered as secondary sources of Hg for the atmosphere, underlining the importance of direct Hg fluxes monitoring to understand its fate in the environment.

Next from SGI 2021

Civil protection interventions - OCDPC n. 558 of 15.11.2018 - Functional recovery of the Provincial Road No. 20 - Municipality of Castiadas (Sardinia)

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