Search

Geochemical systems are complex and the analysis of the shape of the frequency distribution of elements and chemical species often informs about the variability and dispersion related to the underlying dynamics. However, when compositional data are used it is incorrect to investigate concentrations in the Euclidean space. Distribution analysis is aimed at focusing on real coordinates, which can be obtained by applying some appropriate log-ratio transformation. In particular, distributional analysis for compositional data can be applied to isometric coordinates, called balances, obtained through partition of a multi-element data set. As an alternative the same investigation can be performed on indices such as the robust Mahalanobis distance after having ranked log-ratio compositions with respect to some reference composition (i.e. average Earth crust) and having obtained a sort of “measure of change”. By considering this second new perspective, the chemical composition of topsoils of the Campania Region (Southern Italy) was investigated by analysing the concentrations of Al, As, B, Ba, Ca, Co, Cr, Cu, Fe, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, Sr, Th, Ti, V and Zn, in mg/kg, determined on > 3500 samples. Results reveal the presence of complex processes governed by interaction-dominant dynamics where self-organisation appears to play some role.

Over 4000 agricultural and grazing land soil samples were collected for the “Geochemical Mapping of Agricultural and Grazing Land Soil of Europe” (GEMAS) project carried out by the EuroGeoSurveys Geochemistry Expert Group. The samples were collected in 33 European countries, covering 5.6 million km 2 at a density of 1 sample site per 2500 km 2 . All samples were analysed by ICP-MS following an aqua regia extraction. The European median Cd concentration is 0.182 mg/kg in agricultural soil and 0.197 mg/kg in grazing land soil (including eastern Ukraine). The Cd map demonstrates the existence of two different geochemical background regimes in northern and southern Europe, separated by the southern limit of the Quaternary glaciation. Cadmium shows two times higher background concentrations in the older and more weathered southern European soil than in northern European soil. The spatial distribution patterns of Cd in the collected soil samples are mainly governed by geology (parent material and mineralisation), as well as weathering, soil formation and climate since the last glaciation period. Locally, in several areas, the natural anomaly pattern is overprinted by anthropogenic emissions from former mining, ore processing and related metal industries. Some Cd anomalies can be attributed to urbanisation and the use of fertilisers. A comparison of the raw data Cd concentration map with its clr-transformed counterpart and selected single element ratio maps demonstrates that substantial additional information about sources and processes governing the distribution of Cd in agricultural soil at the European scale can be obtained. Results of a PCA, carried out following the classical approach (standardised) versus a PCA based on the statistically acceptable approach, using clr-transformed data, are quite comparable.

International audience; 2108 agricultural soil samples (Ap-horizon, 0–20 cm) were collected in Europe (33 countries, area 5.6 million km2) as part of the recently completed GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) soil mapping project. GEMAS soil data have been used to provide a general view of element origin and mobility with a main focus on source parent material (and source rocks) at the continental scale, either by reference to average crustal abundances or to normalized patterns of element mobility during weathering processes. The survey area covers a large territory with diverse types of soil parent materials, with distinct geological history and a wide range of climate zones, and landscapes.To normalize the chemical composition of European agricultural soil, mean values and standard deviation of the selected elements have been compared to model compositions of the upper continental crust (UCC) and mean European river suspended sediment. Some elements are enriched relative to the UCC (Al, P, Pb, Zr,) whereas others, such as Mg, Na and Sr are depleted. The concept of the UCC extended normalization pattern has been applied to selected elements. The mean values of Rb, K, Y, Ti, Al, Si, Zr, Ce and Fe are very similar to the values from the UCC model, even when standard deviations indicate slight enrichment or depletion. Zirconium has the best fit to the UCC model using both mean value and standard deviation. Lead and Cr are enriched in European soil when compared to the UCC model, but their standard deviation values span a large, particularly towards very low values, which can be interpreted as a lithological effect.GEMAS soil data have been normalized to Al and Na, taking into account the main lithologies of the UCC, in order to discriminate provenance sources. Additionally, sodium normalization highlights variations related to the soluble and insoluble behavior of some elements (e.g., K, Rb versus Ti, Al, Si, V, Y, Zr, Ba, and La, respectively), their reactivity (e.g, Fe, Mn, Zn) and association with carbonates (e.g., Ca and Sr). Maps of Europe showing the spatial distribution of normalized compositions and element ratios reveal difficulties with the use of classical element ratios because of the large lithological differences in compositions of soil parent material. The ratio maps and color composite images extracted from the GEMAS data can help to discriminate the main lithologies in Europe at the regional scale but need to be used with caution due to the complexity of superimposed processes responsible for the soil chemical composition.

Soil geochemistry is often investigated by considering a large number of variables, including major, minor and trace elements. Some of the variables are usually highly correlated due to coherent geochemical behaviour, but the effect of anthropic factors tends to increase data variability, sometimes obscuring natural relationships governing their distributions. In this framework it may be difficult to identify geochemical features linked to natural phenomena as well as to separate geogenic anomaly from the anthropogenic ones. Consequently the identification of background/baseline values may be seriously compromised. However, knowledge about these reference terms is fundamental to manage and protect natural resources on different scales. Moreover, adequate estimations of background/baseline values are possible only if a sufficient number of chemical analyses are stored in complex repositories. In this contribution the multi-element data archive of the Campania Region (Southern Italy) was explored from the CoDA (Compositional Data Analysis) multivariate perspective to characterise its structure. The archive contains abundance data of Al, As, B, Ba, Ca, Co, Cr, Cu, Fe, K, La, Mg, Mn, Mo, Na, Ni, P, Pb, Sr, Th, Ti, V and Zn (mg/kg) determined in 3535 new topsoils as well as information on coordinates, geology and land cover. Under CoDA the proportionality features of abundance data are fully taken into account enhancing their relative multivariate behaviour in the correct sample space. Results indicate that the structure of the whole matrix appears to be constituted by a core that geographically is mainly given by topsoils developed on volcanic materials and several outlier compositions whose origin is different. Anomalous compositions can originate from the robust barycentre all around when the following conditions are present: 1) high Na–K volcanic products, 2) limestones and dolostones with their terrigenous component, 3) flysch deposits or 4) fertiliser contribution. The (1 × D) robust barycentre of the whole dataset together with the variation array of the core represents the most frequent (1 × D) multi-element vector as well as the proportionality relationships among its components. It might be considered a compositional baseline.

Indium is a very rare element, which is usually not reported in geochemical data sets. It is classified as a critical metal, with important applications in the electronics industry, especially in the production of solar panels and liquid-crystal displays (LCDs).Over 4000 samples of agricultural and grazing land soil have been collected for the "Geochemical Mapping of Agricultural and Grazing Land Soil of Europe" (GEMAS) project, carried out by the EuroGeoSurveys Geochemistry Expert Group. Indium concentrations in soil have been analysed using aqua regia extraction followed by ICP-MS. Median values of In for both land use types are nearly identical, 0.0176. mg/kg for agricultural soil and 0.0177. mg/kg for grazing land soil.The spatial distribution patterns of In in European soil are mainly controlled by geology and the presence of Zn and Sn mineralisation. The preference of In to accumulate in the fine-grained fraction of soil with high clay content dominates the major anomaly patterns on the geochemical maps. In the Mediterranean region, secondary In enrichment is visible in karst areas. A notable feature of the In spatial distribution is the large difference between northern and southern Europe, with median values of 0.012 and 0.021. mg. In/kg, respectively, suggesting that, in addition to lithology, weathering and climate are important factors influencing In soil enrichment over time. © 2015 Elsevier B.V.

Two thousand one hundred and eight agricultural soils (0–20 cm depth) collected at a density of one sample per 2500 km2 under the auspices of the Geochemical Mapping of Agricultural Soils (GEMAS) project over most of the European continent have been analysed using the Mobile Metal Ion (MMI®) partial extraction technique with ICP-MS finish. For a number of elements, notably Ce, Ni, and Ca, coherent geogenic patterns have been observed which relate to underlying lithology. For Fe and Al, coherent patterns are also observed but the effects of weathering are evident, and provide a mechanism to explain the acidity of soils in high rainfall areas. Individual anomalies, many related to anthropogenic activity (mining, metallurgy, agriculture) have been observed for Ag, Au, Cu, Pb, Cd and Zn. Comparison of the results with aqua regia digestion and the equivalent National Geochemistry Survey of Australia (NGSA) provides insights into weathering processes and the concept of bioavailability. © 2015 AAG/The Geological Society of London.

During 2008 the GEochemical Mapping of Agricultural Soils (GEMAS) project collected 2108 agricultural (ploughed soil, Ap horizon, 0–20 cm) and 2023 grazing land soil samples (Gr, 0–10 cm) evenly spread over 33 European countries and covering an area of 5.6 million km2. The pH of all samples was determined by one single laboratory applying a 0.01 M CaCl2 extraction, and following a strict quality-control procedure. The resulting pH-value distributions for European Ap and Gr soil are both bimodal. Broad acidic modes, with pH between 4 and 6, and sharp alkaline modes, with pH between 7 and 8 due to the Ca2+ buffer system, are clearly separated. The European median pH is 5.8 for the GEMAS Ap soil samples and 5.5 for the GEMAS Gr soil samples. According to the pH distribution maps, Europe is separated into two main zones: northern Europe with generally lower pH values (Ap: 5.2, Gr: 4.8), dominated by acidic soils occurring in Fennoscandia, and southern Europe with higher pH values (Ap: 6.3, Gr: 5.9), dominated by carbonate rich soils. The separation line coincides with the southern border of the sediments of the last glaciation. The dominant factors controlling pH at the European scale are thus geology (crystalline bedrock) in combination with climate (temperature and precipitation). The GEMAS pH maps mainly reflect the natural site conditions on the European scale, whilst anthropogenic impact is hardly detectable. The GEMAS results provide a unique set of homogenous and spatially representative soil pH data for the continent. The data set defines a dependable continental-scale background, and offers the possibility to calibrate studies on more detailed scales.

Agricultural soil (Ap-horizon, 0–20 cm) samples were collected from 33 European countries as part of the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) soil-mapping project. The Mg data derived from total concentrations (XRF) and two acid digestion methods, aqua regia (AR) and Mobile Metal Ion (MMI®), were used to provide an overview of its spatial distribution in soil at the continental-scale. Magnesium is one of the most abundant elements in the Earth's crust and essential nutrient for plants and animals and its presence in soil is, therefore, important for soil quality evaluation. In this study, the geochemical behaviour of Mg in European agricultural soil was investigated in relation to a variety of soil parent materials, climatic zones, and landscapes. The chemical composition of soil reflects mostly the primary mineralogy of the source bedrock, and the superimposed effects of pre- and post-depositional chemical weathering, controlled by element mobility and formation of secondary phases such as clays. Low Mg concentrations in agricultural soil occur in regions with quartz-rich glacial sediments (Poland, Baltic States, N. Germany), and in soil developed on quartz-rich sandstone parent materials (e.g., central Sweden). High Mg concentrations occur in soil developed over mafic lithologies such as ophiolite belts and in carbonate-rich regions, including karst areas. The maximum extent of the last glaciation is well defined by a Mg concentration break, which is marked by low Mg concentrations in Fennoscandia and north-central Europe, and high Mg concentrations in Mediterranean region. Lithology of parent materials seems to play a key role in the Mg nutritional status of agricultural soil at the European scale. Influence from agricultural practice and use of fertilisers appears to be subordinate. Comparison of the continental-scale spatial distribution of Mg in agricultural soil by using the results from three analytical methods (XRF, AR and MMI®) provides complementary information about Mg mobility and its residence time in soil. Thus, allowing evaluation of soil weathering grade and impact of land use exploitation.

Polycyclic aromatic hydrocarbons (PAHs) are a group of persistent organic pollutants (POPs). They have been identified as a type of carcinogenic substance and are relatively widespread in environment media such as air, water and soils, constituting a significant hazard for human health. In many parts of the world, PAHs are still found in high concentrations despite improved legislation and monitoring, and it is therefore vital defining their profiles, and assessing their potential sources. This study focused on a large region of the South of Italy, where concentration levels, profiles, possible sources and toxicity equivalent quantity (TEQ) level of sixteen PAHs were investigated. The survey included soils from five large regions of the south of Italy: 80 soil samples (0–20 cm top layer) from urban and rural locations were collected and analysed by Gas chromatography-mass spectrometry (GC-MS). Total PAHs and individual molecular compounds from the US Environmental Protection Agency (EPA) priority pollutants list were identified and measured.\ud \ud Results showed that 16PAHs varied significantly in urban and rural areas, and different regions presented discordant characteristics. Urban areas presented concentrations ranging from 7.62 to 755 ng/g (mean = 84.85 ng/g), whilst rural areas presented ranges from 1.87 to 11, 353 ng/g (mean = 333 ng/g). Large urban areas, such as Rome, Naples and Palermo, exhibited high PAHs total concentration, but high values were also found in rural areas of Campania region. Different PAHs molecular ratios were used as diagnostic fingerprinting for source identification: L WMPAHs/HWMPAHs, Fluo/(Fluo +Pyr), BaA/(BaA +Chr), Ant/(Ant +Phe), and IcdP/(IcdP +BghiP). These ratios indicated that PAHs sources in the study area were mainly of pyrogenic origin, i.e. mostly related to biomass combustion and vehicular emission. On the other hand, values in Sicilian soils seemed to indicate a petrogenic origin, possibly linked to emissions from crude oil combustion and refineries present in the region. Finally, results allowed to calculate the Toxicity equivalent Quantity (TEQ BAP) levels for the various locations sampled, highlighting that the highest values were found in the Campania region, with 661 ng g-1 and 54.20 ng g-1, in rural and urban areas, respectively. These findings, which could be linked to the presence of a large solid waste incinerator plant, but also to well-documented illegal waste disposal and burning, suggest that exposure to PAH may be posing an increased risk to human health in some of the studied areas.

Mining activities are among the main sources of potentially toxic elements (PTEs) in the environment which constitute a real concern worldwide, especially in developing countries. These activities have been carried out for more than a century in Chile, South America, where, as evidence of incorrect waste disposal practices, several abandoned mining waste deposits were left behind. This study aimed to understand multi-elements geochemistry, source patterns and mobility of PTEs in soils of the Taltal urban area (northern Chile). Topsoil samples (n = 125) were collected in the urban area of Taltal city (6km2) where physicochemical properties (redox potential, electric conductivity and pH) as well as chemical concentrations for 35 elements were determined by inductively coupled plasma optical emission spectrometer. Data were treated following a robust workflow, which included factor analysis (based on ilr-transformed data), a new robust compositional contamination index (RCCI), and fractal/multi-fractal interpolation in GIS environment. This approach allowed to generate significant elemental associations, identifying pool of elements related either to the geological background, pedogenic processes accompanying soil formation or to anthropogenic activities. In particular, the study eventually focused on a pool of 6 PTEs (As, Cd, Cr, Cu, Pb, and Zn), their spatial distribution in the Taltal city, and the potential sources and mechanisms controlling their concentrations. Results showed generally low baseline values of PTEs in most sites of the surveyed area. On a smaller number of sites, however, higher values concentrations of As, Cd, Cu, Zn and Pb were found. These corresponded to very high RCCI contamination level and were correlated to potential anthropogenic sources, such as the abandoned mining waste deposits in the north-eastern part of the Taltal city. This study highlighted new and significant insight on the contamination levels of Taltal city, and its links with anthropogenic activities. Further research is considered to be crucial to extend this assessment to the entire region. This would provide a comprehensive overview and vital information for the development of intervention limits and guide environmental legislation for these pollutants in Chilean soils.

Organochlorine pesticides (OCPs) have the potential to concentrate in the marine environment and threaten the local marine life. Here, we present the results of a study of the contamination profiles, spatial distribution, possible sources, and potential ecological risk of OCPs in marine sediments from Gulfs of Naples and Salerno, Southern Italy. The total concentrations of OCPs ranged from 0.54 to 99.6 ng/g (average mean: AM = 7.80 +/- 16.3 ng/g). The concentration of OCPs from gulf of Salerno (AM = 9.20 +/- 20.7 ng/g) was higher than Naples (AM = 7.49 +/- 15.3 ng/g). The sediment levels of individual OCPs were (in sequence of concentration) dichlorodiphenyltrichloroethanes (DDTs, including p,p'-DDD, p,p'-DDE, o,p'-DDT and p,p'-DDT) > CHLs (heptachlor, heptachlor epoxide, trans-chlordane, and cis-chlordane) > hexachlorocyclohexanes (HCHs, including alpha-beta-gamma-and delta-HCH) > DRINs (aldrin, dieldrin, and endrin) > hexachlorobenzene (HCB) > SULPHs (alpha-endosulfan, beta-endosulfan, and endosulfan sulfate). DDTs and heptachlor were the highest in proportion among the OCPs. High concentrations of OCPs were observed in the coastal area especially near the cities of Naples and Salerno as a result of terrigenous supply. The occurrence of high residual levels of OCPs found in this study may be attributed to their historical application. Marine dynamics influence the distribution of OCPs, in particular the HCHs, as they are less lipophilic and more soluble. According to established sediment quality guidelines, DDTs may cause ecological risk.

The demand for ‘high-tech’ element resources (e.g., rare earth elements, lithium, platinum group elements) has increased with their continued consumption in developed countries and the emergence of developing economies. To provide a sound knowledge base for future generations, it is necessary to identify the spatial distribution of critical elements at a broad-scale, and to delineate areas for follow-up surveys. Subsequently, this knowledge can be used to study possible environmental consequences of the increased use of these resources. In this paper, three critical industrial elements (Sb, W, Li) from low-sampling density geochemical mapping at the continental-scale are presented. The geochemical distribution and spatial patterns have been obtained from agricultural soil samples (Ap-horizon, 0–20 cm; N = 2108 samples) collected at a density of 1 site per 2500 km2 and analysed by ICP-MS after a hot aqua regia digestion as part of the GEMAS (GEochemical Mapping of Agricultural and grazing land Soil) soil-mapping project in 33 European countries. Most of the geochemical maps show exclusively natural background element concentrations with minor, or without, anthropogenic influence. The maximum extent of the last glaciation is marked as a discrete element concentration break, and a distinct difference occurs in element concentration levels between the soil of northern and southern Europe, most likely an effect of soil genesis, age and weathering. The Sb, W and Li concentrations in soil provide a general overview of element spatial distribution in relation to complexity of the underlying bedrock and element mobility in the surface environment at the continental-scale. The chemical composition of agricultural soil represents largely the primary mineralogy of the source bedrock, the effects of pre- and post-depositional chemical weathering, formation of secondary products, such as clays, and element mobility, either by leaching or mineral sorting. Observed geochemical patterns of Li, W and Sb can be often linked with known mineralisation as recorded in the ProMine Mineral Database, where elements in question occur either as main or secondary resources. Anthropogenic impact has only been identified locally, predominantly in the vicinity of large urban agglomerations. Unexplained high element concentrations may potentially indicate new sources for high-tech elements and should be investigated at a more detailed scale.

In 2017, a geochemical survey was carried out across the Commune of Santiago, a local administrative unit located at the center of the namesake capital city of Chile, and the concentration of a number of major and trace elements (53 in total) was determined on 121 topsoil samples. Multifractal IDW (MIDW) interpolation method was applied to raw data to generate geochemical baseline maps of 15 potential toxic elements (PTEs); the concentration-area (C-A) plot was applied to MIDW grids to highlight the fractal distribution of geochemical data. Data of PTEs were elaborated to statistically determine local geochemical baselines and to assess the spatial variation of the degree of soil contamination by means of a new method taking into account both the severity of contamination and its complexity. Afterwards, to discriminate the sources of PTEs in soils, a robust Principal Component Analysis (PCA) was applied to data expressed in isometric log-ratio (ilr) coordinates. Based on PCA results, a Sequential Binary Partition (SBP) was also defined and balances were determined to generate contrasts among those elements considered as proxies of specific contamination sources (Urban traffic, productive settlements, etc.). A risk assessment was finally completed to potentially relate contamination sources to their potential effect on public health in the long term. A probabilistic approach, based on Monte Carlo method, was deemed more appropriate to include uncertainty due to spatial variation of geochemical data across the study area. Results showed how the integrated use of multivariate statistics and compositional data analysis gave the authors the chance to both discriminate between main contamination processes characterizing the soil of Santiago and to observe the existence of secondary phenomena that are normally difficult to constrain. Furthermore, it was demonstrated how a probabilistic approach in risk assessment could offer a more reliable view of the complexity of the process considering uncertainty as an integral part of the results. Physical and Mathematic Science Faculty (Universidad de Chile); University of Chile [N/A1/2014]; FONDAP [15200001]; ICM [NC130065] Published version This work was supported by startup funds awarded to Linda Daniele and Claudia Cannatelli by the Physical and Mathematic Science Faculty (Universidad de Chile). Linda Daniele also acknowledges the partial use of funds from Program U-Apoya (N/A1/2014) of the University of Chile, FONDAP #15200001 (Centro de Excelencia en Geotermia de los Andes, CEGA) and ICM #NC130065 (Nucleo Milenio Trazadores de Metales, NMTM).

Potentially toxic elements (PTEs) are a major worldwide threat to the environment due to the constant global increase in industrial activity and urbanisation. Several studies have provided detailed maps and a better understanding of the spatial distribution patterns of PTEs in different matrices, but the majority of these studies have simply neglected the compositional nature of geochemical data. The aims of this study are to reveal the compositional behaviour and relative structure of 15 PTEs (subcomposition) in Campania, one of the most contaminated regions in Italy, and to quantify the spatial abundance and identify the possible origins of these PTEs. Robust compositional biplots were used to understand the natural grouping and origin of the PTEs. Ratios of specific subcompositions (balances) of PTEs were calculated to map the spatial patterns and identify the spatial variability of the PTEs. This study presents the preliminary steps needed to quantify and analyse the relative difference in the spatial abundance of PTEs by applying a compositional abundance index. In addition, a new soil contamination compositional index (SCCI) was elaborated to quantify topsoil contamination by the 15 PTEs and related subgroups following the compositional structure of the geochemical data. The elevated spatial abundance of the 15 PTEs is related to highly urbanised (Naples and Salerno), highly industrialised (Solofra) and intensely cultivated areas (Sarno River Basin), where the high dominance of elements from the anthropogenic subgroup (Pb, Sb, Sn and Zn) and high SCCI values suggest that contamination is from anthropogenic sources. The high spatial dominance of elements from the volcanic rock subgroup (As, Be, Se, Tl and V) in these same areas is likely related to geogenic sources, including alkalic pyroclastic rocks. Although the high spatial abundance of Group B elements (Cd, Cr, Co and Ni) is related to Terra Rossa soils and shaley facies of siliciclastic rocks of the southern Apennines, these same elements can also reach high abundances and reflect contamination (i.e. high SCCI values) from urbanised and industrialised areas due to e.g., tanneries and alloy production. Other high spatial abundances of the 15 PTEs with little or no contamination (i.e. very low SCCI values) can be related to nearby carbonate massifs, where a mixture of geogenic factors including weathering, advanced pedogenic processes, adsorption and co-precipitation with Fe-/Mn-oxyhydroxides and the presence of pyroclastic material might all be responsible for an increase in abundance. The lowest spatial dominance of the 15 PTEs occurs in the northeastern and southwestern siliciclastic zones of the Campania Region, where there is a low level of urbanisation and industrialisation and therefore contamination from any source can be excluded.

This study assesses the distribution of Au, Ag, Pt, and Pd in the topsoils from the Campania Region (Southern Italy). The 13,600 km2 study area was divided using a 16 km2 grid in the suburban and agricultural areas, and a 4 km2 grid in urban areas and 2120 topsoil samples were analyzed by ICP-MS after an aqua regia digestion. The maximum concentrations of Pt and Pd were 278.1 and 431.9 ppb, respectively, however, >50% of samples analyzed during this study had concentrations of Pt and Pd below the instrumental detection limit. Gold and Ag concentrations ranged from 0.2 to 1278.6 ppb, and 2 to 8132 ppb, respectively. The geochemical data was first elaborated into dot maps to assess the relationship between the real concentrations across the region. Point data were subsequently classified using their statistical percentile thresholds (25th, 50th, 75th, 95th and 98th). A C–A fractal model was then applied to the data to assess their spatial distribution and determine thresholds representing changes in concentrations highlighting background/baseline and anomalous components. Major results indicate that: (1) application of C–A fractal model on multifractal gridded data allows the discrimination of geochemical anomalies from background concentrations; (2) Au, Ag, Pt, and Pd in Campania topsoils clearly reflect both natural and anthropogenic influences on their occurrence and distribution; (3) a clear relationship exists between the abrasion of automobile catalytic converters, the occurrence of PM10 aerosol particles, and elevated concentrations of Pt and Pd in soil; (4) the concentration of Ag and Au in the soils of the study area reflect differences in the origin of their source material in the volcanic products of northern (Roccamonfina) and central Campania (Campi Flegrei, Vesuvius); and (5) clear enrichment in Au and Ag are located corresponding to the main urban areas.

Digital image processing analysis was carried out on As in topsoils of the Campania Region (Italy) to recognise any unknown spatial patterns. The highest As concentration is related to topsoils developed on the NW–SE-trending carbonate massifs overlain by pyroclastic rocks where the highest spatial variability and gradient magnitude of As concentration and the highest fault density were also observed. High As concentrations were also found in topsoils over volcanic rocks which played a control on its distribution pattern. The low As values are associated with topsoils along large fluvial valleys where the activity of rivers disturbed the As pattern by transporting larger grain-sized stream sediments with low As concentrations.

This work discusses the results of a geochemical survey conducted in the Salerno urban area to determine the sources patterns of major, minor, trace and ultra-trace elements in soils. In particular, the study focused on elements that are potentially toxic and listed in the environmental Italian legislation (D.L. 152/06), in order to effectively monitoring an important aspect of environment health. A total of 151 topsoil samples were collected, air-dried and sieved (

Concern about health effect of Potentially Toxic Elements (PTEs) has led to an increasing global attention about their concentration levels in the environment. Soil geochemistry has been widely used as a tool for environment monitoring. This study investigates topsoil geochemistry of Campania region (Southern Italy) and (i) allows a reliable overview of the PTEs (As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, Sb, Se, Sn, Tl, V and Zn) concentration in soils, (ii) enable the investigation of the main factors governing PTEs geochemical variation on a regional scale. Over 7300 topsoil samples were collected from the survey area, which occupies an area of about 13.600 km2. Samples were analyzed for pseudo-total content of 53 elements (major and trace elements) by ICP-MS after aqua regia digestion. Data analysis was performed taking into account both raw data and their compositional nature as a tool for the PTEs environmental evaluation and origin investigation. As, Be, Cu, Pb, Sn, Tl, V and Zn in soils of Campania region show higher median concentration levels than Italian and European ones. In addition, all PTEs exceed the residential/ recreational intervention limit (CSCA) set by Italian legislation. The variation structure of compositional data had been visualized using compositional (clr) biplots and displaying the individual sample observations according to their parent rock. Clr-biplot analysis allowed us to recognize geochemical processes controlling most of soil chemical signatures. Multivariate analysis has been performed and three principal components were determined. PC1 is controlled by enrichment of elements deriving from dominant parent rocks of the area (siliciclastics and volcanoclastics). On the other hand, PC1 reveals the presence of an elemental association dominated by Na, K, U, Th, Zr, Ti, Tl and Be (clr variables), which are pathfinder element of soils developed from volcanic parent material. The second (PC2) component well discriminates the geochemical mobility of the elements in soils. The third (PC3) component reveal the presence of an anthropogenic association (Hg, Sb, Pb, Sn, Au, Ag) which depict a marginal contribution in soil geochemistry of the study area. The generation of clr-biplot helped us in a deeper interpretation of single element spatial distribution patterns. As, Be, Sn, Tl and V spatial distribution shows dominance in soil developed from volcanic products of the main volcanic complexes. Our study showed that element such as Be, Sn and Tl naturally exceed the contamination thresholds in almost the entire territory, due to a quite elevated background concentration values. Hence, Campania region con not be considered entirely contaminated (at this scale) by such elements. Co, Cd, Cr and Ni are more abundant where siliciclastic parent rocks occur.

Uranium, thorium and potassium are distinguished in different compartments of the environmental media according to the inputs, the fate and the distribution patterns that occur in the ecosystems. Thus, an understanding of the sources patterns and behaviours of these elements in soils, their rock-soil relationships and potential toxicity or deficiency problems associated with them is nowadays a relevant concern for environmental protection and human health. A robust compositional computation analysis coupled with frequency spatial-method (Fractal model) is applied on 3 selected elements (U, Th and K), based on a large dataset of 7134 topsoil samples over the whole Campania region, and investigated elements concentrations were analysed (after aqua regia extraction) by inductively coupled plasma mass spectrometry (ICP-MS). In this survey, U concentrations ranged from 0.05 to 43.2 mg kg−1 with a mean value of 3.35 mg kg−1, Th concentrations ranged from 0.3 to 64.30 mg kg−1 with a mean values of 11.95 mg kg−1 and K concentrations ranged from 0.03 to 5.97% with a mean value of 0.68%. The mean values for U and Th are slightly above the mean crustal abundances, while K is slightly below them. Fractal mapping of Centred-log transformed (clr) data of investigated elements show that the U, Th and K geochemical anomalies can be ascribed to geology-related volcanic sources. Indeed, the highest values in soils were assessed in the surveyed alkaline magmatic areas in the central-western part of the region characterized by volcanic rocks, whereas lowest values are found in areas characterized by silico-clastic and carbonate deposits, occurring mostly in the southern and eastern part of the region. Evidence from this study showed that compositional data transformations such as clr transformation could help to avoid artefacts, prior to statistical computations.

In this paper we present a comparison of statistical and spatial distributions between Pb, Cu and Zn concentration data and clr-transformed data of 3669 topsoil samples from the Campanian Region. Results show that both approaches, the classical univariate analysis and the compositional data analysis, are necessary to understand the real structure of the data and shed light on different aspects. In particular, the spatial distributions of concentration (‘raw’) data and clr-transformed data of the three elements differ completely. Raw data essentially represent a high anthropogenic impact, requiring an additional human health risk assessment for the three investigated elements. The information obtained by the clr-coefficient maps reveals the geogenic contribution to the element distribution. To better constrain the degree of contamination due to these potentially toxic elements and their impact on human health, we present an RGB composite map of Pb, Cu and Zn. This map unravels potential sources of contamination and locates the areas where concentrations exceed thresholds established by the Italian legislation.

In the framework of the GEMAS project, 2211 samples of agricultural soil (Ap, 0-20cm, regularly ploughed fields), and 2118 samples from land under permanent grass cover (Gr, 0-10cm, grazing land soil) were collected across almost the whole European continent, at a density of 1 sample site/2500km2, in accordance with a common sampling protocol.Among many other elements, the concentrations of Co, Cr, Cu and Ni in European soil were determined by ICP-MS after a hot aqua extraction, and WD-XRFS analytical methods, and their spatial distribution patterns generated by means of a GIS software.The presence of mafic and ultramafic rocks, ophiolite complexes and mineralisation, is widespread across the European continent, and seems to explain most of the variability of the elements studied in this paper. A large belt, north of the last glaciation maximum limit, is generally dominated by lower concentrations compared with central European and Mediterranean areas and to some areas in Northern Europe where higher Co, Cr, Cu and Ni values also occur.The application of the guideline value set for Cu and Ni by the EU Directive 86/278/EEC to the Ap soil samples of the GEMAS data set highlighted that at the continental scale the use of a unique reference interval is a tool of limited effectiveness; the lithological variation, occurring across a whole continent, generates changes in the geochemistry of soil, which cannot be accommodated by using a single reference interval even if it is very wide. The GEMAS data set should form the sound basis to set at the European scale the geochemical background reference intervals, at least, for regions sharing common lithological settings and a common geological history. •Geochemistry of Co, Cr, Cu and Ni•Mineral deposits in Europe with Co, Cr, Cu and Ni•Distribution of Co, Cr, Cu and Ni in European agricultural and grazing land soil•Comparison of aqua regia extractable and total element concentrations in soil•Comparison of Cu and Ni concentrations with European guideline values. © 2015 Elsevier B.V.

The GEMAS (geochemical mapping of agricultural soil) project collected 2108 Ap horizon soil samples from regularly ploughed fields in 33 European countries, covering 5.6 million km(2). The

This study demonstrates the spatial distribution of Be and its possible sources by using the high density Campanian topsoil dataset. A combination of univariate and multivariate statistical analysis with multifractal methods were performed on the raw-, and compositionally transformed data set to recognize the spatial patterns of Be and its background values. Specific groups of elements were chosen based on the compositional clr-biplot to implement multiple sequential binary partitions which were used in the calculation of balances. Balances enabled us to reveal the dominance and relation between specific groups of elements. Ratio maps based on balances were also made to better understand the compositional behaviour of Be in a multidimensional space. Index of chemical weathering (CIA) was calculated to explore the advancement of pedogenetic processes which might govern the Be distribution. Enrichment Factor (EF) was used to discover the possible anthropogenic contamination of Be. In addition, different thematic maps (e.g. fault zones, bauxite mineralization spots, hydrothermal springs, pyroclastic and carbonatic rocks distribution) were involved to support and verify our interpretation. Beryllium distribution is influenced by multiple geogenic factors. We proved that Be anomaly in topsoils is not only influenced by the presence of volcanoclastic deposits but the advancement of pedogenetic processes (e.g. chemical weathering, rubification) is equally or even more important. We pointed out that Be anomaly is mainly concentrated in topsoils developed over the oldest pyroclastic deposits in Roccamonfina and over carbonatic massifs where pedogenesis is more advanced. The distribution of pyroclastic deposits in the Campania Region was also demonstrated independently by using different balances (groups of elements). Some high Be anomaly can be interpreted as local peculiarities associated with bauxite mineralization and the presence of fault zones along which hydrothermal deposits and springs are particularly rich in Be. Finally, Be background values reflect geogenic origin and exceed the intervention limit for residential area in the vast majority of the Campania Region, hence decision-makers should take into consideration the local geological conditions when determining intervention limits.

This study shows the statistical and spatial distribution of Mo, Sn and W in topsoils of the Campania Region. Topsoil samples were collected based on a 16-km 2 and a 3.8-km 2 cell-sampling grid in the suburban and urban areas, respectively. Samples were analysed for Mo, Sn and W concentrations by ICP-MS after an aqua regia digestion. Multifractal methods and RGB (Red, Green, Blue) composite maps of untransformed and centred log-ratio (clr) transformed datasets have been used to recognize spatial patterns of the three elements. Continuous low-value zones were revealed in topsoils over siliciclastic rocks where rivers might have redistributed sediments with low concentrations. A molybdenum anomaly south of Mt Cervati can be related to lacustrine argillaceous sediments containing sulphide minerals. Tin hot spots and anomaly zones were revealed along the Volturno River and urban areas. Tungsten is the element out of the three which is best related to the presence of volcanic rocks belonging to the Neapolitan Potassic Province.

A new GIS based human health risk assessment methodology developed for soil contamination has been applied to a selected area located in Campania region (Italy). The area is about 220 km2 wide and it is located between the provincial capital cities of Avellino and Salerno; it was selected since most of it already resulted affected by an high risk level according to a previous human health risk assessment procedure based on a lower density regional prospecting. The geochemical database used for the aims of this study contains a total of 584 top soil samples, partly proceeding from the previous regional sampling and partly (102 samples) collected ex-novo during the spring/summer 2015. The statistical and cartographic elaboration for 15 potentially toxic elements (Sb, As, Be, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, Sn, Tl, V, Zn) concentration in soil are presented, analyzing the overcoming of the Contamination Thresholds (CSC) established by the Italian Decree (D. Lgs. 152/06). With the aim of better defining the geometry and the extension of high risk areas within the selected territory, the same GIS aided technique used to assess the environmental risk at regional scale was applied at local scale to benchmark its presumable scalability. Some significant pollution hot-spots were identified, close to public parks and agricultural areas, with a high risk for local population. In these restricted areas, an in-situ geochemical characterization and a Tier 2 site-specific risk assessment procedure should be carried out, in order to confirm if a remediation action is definitively needed.

Clinopyroxene and olivine are ubiquitous phases in Somma-Vesuvius (SV) volcanics and for the first time they were systematically studied in several products younger than 40ka. In this manuscript chemical compositions (major, trace and rare earth elements) of a large set of olivine and clinopyroxene crystals from selected rock samples are presented and discussed. Fourteen pumice samples from Plinian pyroclastic deposits as well as three scoriae and eight lava samples from inter-Plinian deposits were collected. A representative number of olivine and clinopyroxene crystals (n~50) were selected for each sample and analysed by electron microprobe and laser ablation inductively coupled plasma mass spectrometer, resulting in a large database, which is now available to the scientific community. All studied eruptive products contain olivine and clinopyroxene crystals spanning a wide range of compositions. Olivines show Fo content varying from 91 to 68, while clinopyroxenes display Mg# ranging from 93 to 71. In samples younger than A.D. 79, the more evolved (Mg#82–72) clinopyroxene crystals show clear Ca enrichment (~23.5–24.5wt% CaO) with respect to those from older samples (before-A.D.79, ~23–21wt% CaO). The results corroborate disequilibrium between olivine, clinopyroxene and the hosting melt, and an increasing role of carbonate assimilation in SV magma evolution in the last 2ka. The database here produced is thought as a share product that makes available mineral data and can be used for further studies by researchers to investigate geochemical evolution of the SV system.

Tap water is a fundamental resource for everyday life, it is subjected to several routine controls and needs to fulfill many compliance scheme. Several elements are monitored on a regular basis, but many trace chemical elements are not usually analyzed, so there is the need to have some kind of indication about their concentration and variation ranges in order to better assess the water quality. An opportunity for such investigations has been provided by a project of the EuroGeoSurvey Geochemistry Expert Group aimed at the characterization of groundwater geochemistry using bottled mineral waters purchased in supermarkets all over Europe which included also the analysis for comparative purpose, of tap water. The initial tap water database of 24 sites has been subsequently increased to the final number of 157 distributed all over Italy and representative of end-user situations (either private houses and public places). In the samples, pH, conductivity and concentrations of 69 elements (Ag, Al, As, B, Ba, Be, Bi, Ca, Cd, Ce, Co, Cr, Cs, Cu, Dy, Er, Eu, Fe, Ga, Gd, Ge, Hf, Hg, Ho, I, K, La, Li, Lu, Mg, Mn, Mo, Na, Nb, Nd, Ni, Pb, Pr, Rb, Sb, Sc, Se, Sm, Sn, Sr, Ta, Tb, Te, Th, Ti, Tl, Tm, U, V, W, Y, Yb, Zn, Zr, Br -, HCO 3 -, Cl -, F -, NH 4 +, NO 2 -, NO 3 -, PO 4 3-, SO 4 2-,SiO 2) were measured at the BGR geochemical laboratories. Some major elements (Ca, HCO 3 -, Mg), the dominant water type, display limited range of variation whereas for others (Na, Cl -) the scattering is wider (3 orders of magnitude). Only one sample for Cl and two samples for NO 3 - are above the recommended EU and Italian guidelines. Clear influence of bedrock geology and/aquifer composition is clear for some elements (e.g. As, F, Rb, V, U), other elements are indicator of mixing with deep formation water or sea-spray contribution (e.g. Br, I), others reflect also peculiar geographic area (e.g. B in Tuscany, Se in Emilia-Romagna). Factor analysis enabled the identification of a "corrosion" factor which includes Pb, Zn, Cd, Cu, Mn, Sn and Fe, all elements which are preferentially related to interaction with the distributing system pipelines.

This review paper is intended to be a guideline to novices on how to conduct research on silicate melt inclusions in volcanic environments, which analytical techniques are more suitable to gather the desired data and the major pitfalls scientist may encounter. Silicate melt inclusions (SMIs) are small quantities of silicate melt that are trapped in minerals during their growth or crystallization. They contain liquids formed in equilibrium with their host minerals and therefore record the liquid line of descent of magmatic systems. Upon trapping, SMIs become ideally closed to the surrounding environment, and behave as time capsules, giving important information about processes that originated magmas and the nature of their mantle source. A melt inclusions investigation is composed of several steps: (1) a detailed petrographic study to characterize and select representative SMIs, with the aim of identifying Melt Inclusions Assemblages (MIA), the only reliable tool to assess that SMIs obey Roedder's rules and have not re-equilibrated following entrapment; (2) a careful preparation of samples for re-heating experiments and microanalysis; (3) high temperature studies in order to homogenize the SMIs and be able to perform chemical analysis; (4) interpretation of SMIs data, which should always be compared with bulk rock composition and relevant experimentally derived liquid compositions. We suggest that the search for good SMI candidates for study will be achieved by good petrographic analysis of SMIs and detailed petrographic information (size, shape, appearance, position relative to the host and other SMI within the same host). If the goal of a SMIs study is to determine volatile concentrations, assessing the relative time of trapping among SMIs is of paramount importance, as it allows understanding if the variation in volatile concentrations is consistent with a certain magmatic physical–chemical process. Researchers that choose to work with SMIs face several challenges. SMIs are not always hosted in all samples or they can be difficult to recognize (mostly due to their small size). Additionally, due several processes, such as post-entrapment crystallization, boundary layer and sampling melt heterogeneity at the micron scale, they may not be representative of the original trapped melt composition.

This work was carried out as the Italian contribution to the EuroGeoSurveys GEMAS project, the objective of which was the geochemical characterisation of agricultural and grazing land soil in Europe. Soil samples were collected at an average sampling density of 1 site per 2500km2. Two different sample types were collected in Italy: (1) 121 samples of agricultural soil (Ap) on regularly ploughed land to a depth of 20cm, and (2) 121 samples of grazing land soil (Gr) (land under permanent grass cover) to a depth of 10cm. All soil samples were air dried, sieved to

A total of about 20,000 stream sediment samples from about 13,000 km(2) were collected in Sardinia and analysed for eleven elements (Ag, Co, Cr, Cu, F, Hg, Mn, Mo, Ni, Pb, Sb and Zn) by Ente Minerario Sardo (EMS), aimed at mineral exploration We have reutilized 16,890 samples (covering an area of 7987 km(2)) of the above data to compile geochemical baseline maps for all single elements as well as maps showing the regional variability of factor scores resulting from R-mode factor analysis. This type of maps has a particular relevance to environmental issues, especially in a region such as Sardinia which has been mined since pre-Roman times. (C) 1997 Elsevier Science B.V.

In this work we compare the inorganic content of bottled mineral water, steadily increasing as a source of drinking water, and tap water which is often affected by intensive chemical treatment Bottled mineral water should be representative of the hydrogeochemical composition of groundwater, whereas tap water could derive from multiple sources such as groundwater or surface water including rivers and reservoirs. The data of this paper were collected within a project carried out by the EuroGeoSurvey Geochemistry Expert Group aimed at the characterization of groundwater geochemistry using bottled mineral waters purchased in supermarkets all over Europe which included also the analysis, for comparative purposes, of tap water. The comparison of two extensive databases of 69 elements on 157 tap water samples and 178 bottled mineral waters on Italian territory enabled the recognition of very wide ranges of variation in both databases. The elements with the highest variation are Y, Li, U, I, HCO3−, Be, Yb, Tm, Zr, Lu, F, and Cs in the bottled mineral database and Ga, PO43−, Zn, Mg, Ti, Th, Cd, Pb, and Cu in the tap water database. The first group of elements in bottled mineral water includes elements with localized very high concentration due to prolonged interaction with unusual rock types, whereas the second group of elements in tap water includes elements that are released by corrosion reaction with the material of the distributing systems. Aside from these differences, tap water displayed a much more restricted range of variation for major ions compared to bottled mineral water because of quality guidelines imposed by Italian Law for selected major ions (Ca, Cl−, SO42−). Some elements do not display statistically different distributions between the two databases (As, Cr, I, Li, Mo, Rb, Sr, Se, U, V) and for some of these (e.g., Cr and V) non-natural sources cannot be excluded in both databases (e.g. pipeline corrosion or container leaching). The spatial distribution of the ionic species provides similar information as far as the role of geology, groundwater condition and, additional sources is concerned. Among the elements displaying significant differences, Al, Cd, Cu, Fe, Ni, Pb and Zn are strongly enriched in tap water samples, whereas Be, Cs, Sb, Sn and Tl are significantly enriched in the bottled mineral water. The group of elements enriched in tap water is controlled also by corrosion processes, so their spatial distribution is random and virtually unrelated to geological or geochemical conditions. Among the elements enriched in the bottled mineral water group, Sb derives from PET container leaching, whereas the other elements likely derive from water–rock interaction.

More than 1·5 million people live in or near the Phlegrean Volcanic District (PVD) in southern Italy, which represents one of the most carefully studied volcanic hazard areas in the world. Throughout its history, the style of volcanic activity has varied greatly, from relatively quiescent lava flows to explosive phreatomagmatic eruptions. The goal of this study is to develop a more detailed understanding of the physical and chemical processes associated with the Solchiaro eruption in the PVD. The PVD includes three volcanic fields: the Campi Flegrei (CF) caldera and the volcanic islands of Ischia and Procida. The Solchiaro eruption on the island of Procida is one of the few primitive (less evolved) eruptions in the PVD and can provide information on the source of the more evolved magmas associated with this volcanic system. One of the more important chemical parameters that determine the style of volcanic eruptions is the volatile budget of the magma before and during eruption. Melt inclusions (MI) provide the most direct information on the volatile contents of the pre-eruptive melt in the source region for the PVD. The composition of the melt phase before eruption was determined by analyzing the major, minor and trace element and volatile contents of 109 MI in olivine from four samples of the Solchiaro eruption, representing different stratigraphic heights in the deposits and, therefore, different relative times of eruption. Olivine compositions vary from Fo. 82 to Fo. 88, with one maximum value of Fo. 90. The compositions of the MI in olivine were corrected for post-entrapment crystallization (PEC) and for Fe loss by diffusion. Most (97 out of 109) of the MI studied are classified as 'normal' MI because they show chemical evolution trends consistent with that of bulk-rocks from the PVD. Two types of anomalous MI were also recognized based on their major and trace element compositions: (1) Sr-rich MI, and (2) enriched MI that are variably enriched in TiO. 2, K. 2O, P. 2O. 5, large ion lithophile elements, high field strength elements and rare earth elements relative to 'normal' MI. These MI probably originated from dissolution-reaction-mixing processes in the mush zone of the magma body. 'Normal' MI include both bubble-bearing and bubble-free (containing only glass ± trapped chromite) types. Bubble-free MI most closely record the pre-eruptive volatile content of the melt over a range of temporal and spatial conditions. The observed trends in CO. 2 contents of MI versus crystallization indicators (e.g. Al. 2O. 3/CaO) support the interpretation that variations in the volatile contents of bubble-free MI reflect real variations in the volatile budget of the melt during the evolution of the magma. The correlation between CO. 2 contents of MI and the relative stratigraphic position of each sample is consistent with eruption of a volatile-saturated magma that initially ascended through the crust from an original depth of at least 8 km. The magma ponded at 4-2 km depth prior to eruption and crystallization and the concomitant volatile exsolution from the saturated melt in the shallow chamber triggered the Solchiaro eruption. As the eruption proceeded, the Solchiaro magma continued to ascend through the crust to a final storage depth of about 1 km. © The Author 2011. Published by Oxford University Press. All rights reserved.

The use of bottled mineral waters use is increasingly becoming popular and the need for better knowledge of their chemical composition is a key issue for defining their quality, particularly for those elements that are not monitored on a regular basis. The link between geology and water chemistry is well known and can lead to extreme differences in element distribution and is an issue that needs to be addressed. Such an opportunity has been provided by a project of the EuroGeoSurvey Geochemistry Expert Group aimed at the characterization of groundwater geochemistry using bottled mineral waters purchased in supermarkets all over Europe. On these waters pH, conductivity and concentrations of 69 elements and ions were measured at the BGR geochemical laboratories. On a total of 1785 “samples”, 158 represent waters bottled in Italy in 126 different sites scattered throughout the country. Most of the purchased mineral water is packaged in PET bottles. In this paper, the dataset concerning Italy has been used to provide an overview on the relationship between natural concentration of the determined chemical elements in groundwater and geo-lithological features. These relationships have been investigated mostly taking into account the surface geology and other information available on water sources. Application of R-Mode factor analysis to the data set allowed the determination of the possible relationship between the distribution of individual elements and lithology or other surface enrichment phenomena. In particular waters draining through volcanic rocks are enriched in elements such as As, B, Br − , Cl − , Cs, I, K, Li, Na, NO 3 − , PO 4 3− , Rb, Sc, SiO 2 , Sr, Te, Ti, and V up to 3 orders of magnitude higher than waters draining through other lithologies. REE and Y show significant difference in median concentration due to interaction of waters with plutonic rocks. Many elements have a large spread of concentrations, which reflects natural variations and interaction with particular lithologies. One of the five R-mode factor analysis associations, recognized as being representative of elements analysed shows high nitrate and V loadings along with As, PO 4 3− and Se. The latter association probably reflects a sign of anthropogenic contribution in some aquifers in volcano-sedimentary or silico-clastic deposits and in intensively cultivated areas.

"vesuvius volcano is one of the most studied volcanoes in the world. The famous eruption of 79 A.D. was not fully appreciated, from a volcanological point of view, until the discovery and excavation of Pompeii and Herculaneum in 1700. Since that date, the fame of the volcano grew along with the interest for natural sciences, and Vesuvius became the volcano on which were tested the new theories on the Earth Sciences, because of its continuing activity and easy accessibility. Since 1944, the volcano entered into a stage of quiescence and, as a consequence, the interest of volcanologists and the funding for w~lcanological research slowly declined with time. This situation perdured until the beginning of the '70s. A new assessment of the relevance of the 79 A.D. eruption was made by Lirer et al. (1973). Dolfi and Trigila (1978) made a study on the role of water during the 1944 eruption. At the same time, new attention was paid to the possible effects of a re-awakening of the dormant giant. A leading role in this field was played by the Osservatorio Vesuviano, the volcanological observatory founded in 1841 and devoted to the surveillance of the Neapolitan volcanoes. The new researches funded by the National Council of Research of Italy ( CNR ) through the Progetto Finalizzato Geodinamica had important consequences. The conference "I vulcani attivi dell'area napoletana" (The active volcanoes of the Neapolitan area), organized in 1977, was the first at tempt to recall the attention of local authorities to the problem of volcanic risk. The first maps ofw?lcanic hazards for lava flows and lahars (Scandone, 1977; Barberi et al., 1977) were presented during that meeting. The concerted effort of the Osservatorio Vesuviano, the University of Naples and the University of Pisa produced at the end of the seventies and beginning of the eighties relevant findings in the knowledge of the volcano. The works of Delibrias et al. ( 1979 ) and Carta et al. ( 1981 ) provided new insights into the volcanological history of Vesuvius both for the period 25,000present and 1631-1944. Sheridan et al. (1981) made a model of the possible role of magma-water interaction during the eruption of 79 A.D. Cortini and Hermes ( 1981 ) provided isotopic evidence of a multisource origin of the potassic magma of the volcano. Barberi and Leoni (1980) and Barberi et al. ( 1981 ) investigated the role of the magma chamber of Vesuvius during plinian eruptions. Scandone and Cortini (1982), Barberi e~ al. (1983), Sheridan and Malin (1983) made comprehensive reviews of the volcanic hazard of the volcano. Since the beginning of 1980 the number of papers on Vesuvius, published in international journals, grew exponentially. This phenomenon was the result of the continuing activity of the Progetto Finalizzato Geodinamica and, since 1983, of the National Volcanological Group sponsored by the CNR. We cite only a few of the papers published during this period. Gasparini et al. ( 1981 ) made a thermal model of the magma chamber feeding plinian eruptions; Belkin et al. (1985), and Cortini el al.

Fluid and melt inclusions and geochemical features of alkali syenite, mafic, and ultramafic cumulate xenoliths in the last ignimbritic event (volcanism up to 300 ky.b.P.) at the island of Ventotene in the Pontine archipelago (Gaeta Gulf) were investigated to establish the genesis and evolution of the fluids trapped in the inclusions. Ranges in lead isotopic compositions of the xenoliths as a group are narrow: 206Pb/204Pb:18.778–18.864; 207Pb/204Pb:15.641–15.701; 208Pb/204Pb:38.858–39.090; the values overlap among the groups, implying that the xenoliths are closely related. The xenoliths straddle the best-fit line describing the regional NW-SE variation of values for uranogenic Pb in volcanic rocks from the Roman alkaline province. The similarity between the xenoliths and volcanic rocks permits the interpretation that the xenoliths are representative of the source region of the volcanic rocks, residues after partial melting of the source region or fractional crystallization of the volcanic rocks, or even that the xenoliths represent assimilants obtained during the evolution of the magmas that produced the volcanic rocks. Xenoliths belonging to the ultramafic-mafic cumulate group contain only silicate melt inclusions ± vapor bubble ± droplets of an opaque phase and rarely some CO2 trapped in silicate melt inclusions. Xenoliths in the alkali syenite group have three types of fluid inclusions: (1) single phase vapor and silicate melt inclusions; (2) two-phase silicate melt + salt, silicate melt + CO2 (V), aqueous (L + V), and silicate melt + vapor inclusions, and (3) three-phase and multiphase inclusions: CO2 (L) + CO2 (V) + H2O; silicate melt + saline melt + H2O ± birefringent or opaque trapped minerals; H2O + salt + silicate glass ± birefringent trapped minerals. During heating experiments, melting of salt occurs at temperatures from 565 to 815°C, depending on the water content of the inclusions. Homogenization of the vapor bubble occurs from 850–1160°C, and complete melting of the silicate glass at about 950°C. The highly variable proportions of the individual phases in the silicate melt + salt + H2O inclusions and the coexistence of silicate melt + CO2 inclusions indicates immiscibility during the crystallization of the magma. Primary and secondary CO2 inclusions in the alkali syenite suite indicate lower densities (from 0.10 to 0.22 g/cm3) than those resulting from primary CO2 inclusions in the gabbroic suite (from 0.34 to 0.42 g/cm3). The P-T trajectory of the probable fluid evolution path shows that the crystallization of gabbro occurred between ∼1 and 1.4 kbars, whereas alkali syenite crystallized between ∼200 and 400 bars. The secondary H2O inclusions in alkali syenite were trapped in the later stages of the hydrothermal process and at much lower temperatures (130–290°C), but at pressures relatively close to those of alkali syenite crystallization. The almost isobaric conditions during the final stage of the fluid evolution path are explained by the very shallow emplacement of the alkali syenite intrusive body.

Fluid inclusions are rare in peralkaline granitoid xenoliths entrained in volcanic units at Pantelleria, Italy, suggesting that the shallow magma bodies in this peralkaline center do not develop extensive hydrothermal systems. Only one of the samples studied, an alkali-feldspar granite xenolith, contains abundant fluid inclusions in quartz. Four types of aqueous fluid inclusions are distinguished: Type I brines, including early, highly saline, NaCl-bearing inclusions (T(h L) = 508-560-degrees-C; salinity = 60-68 eq. wt.% NaCl) that occur in random groups (Type Ia) and late, NaCl-bearing inclusions (T(h L) = 386-450-degrees-C; salinity = 37-45 eq. wt.% NaCl) along secondary healed fractures (Type Ib); Type II vapor-rich aqueous inclusions (T(h V) > 600-degrees-C) associated with Type Ia inclusions; Type III biphase (L + V) aqueous inclusions (T(h L) = 360-390-degrees-C) along secondary healed fractures; and minor Type IV high-density biphase (L + S) brines. The earliest fluids to be trapped (T > 600-degrees-C) are represented by vapor-rich inclusions (Type II), which suggest boiling of the fluid phase. No coexisting brines were trapped, however, as all brines were trapped at temperatures below 560-degrees-C. High-salinity fluid phases circulated in the system down to temperatures of about 380-degrees-C, suggesting prolonged endogeneous fluid circulation in the shallow intrusive body that was the source for the xenolith. In contrast to the cooling history of many shallow-level granitic bodies, there is no evidence of pervasive circulation of low-temperature ( < 300-degrees-C), low-salinity fluids of largely meteoric origin

Pyroxenite xenoliths in the Salt Lake Crater nephelinites of the Koolau Shield (Oahu, Hawaii) consist of clinopyroxene + spinel +/- olivine +/- garnet +/- orthopyroxene +/- amphibole +/- phlogopite. Two successive generations of fluid inclusions are recognized: - (1) Inclusions containing superdense CO2 (+/- H2O) (d = 1.21 g/cm3) are sometimes apatite-bearing, and occur only in clinopyroxene. Initial melting occurs precisely at the temperature of partial homogenization to liquid from -58.2 to -56.5-degrees-C and final melting in the range -57.9/-50.8-degrees-C. - (2) Secondary high-density (1.18-0.60 g/cm3) monophase CO2-rich inclusions occur in all minerals. Melting temperatures are recorded between -60.0 and -56.6-degrees-C, while homogenization temperatures (L+V --> L) vary between -58.4 and +30.0-degrees-C. The wide interval of melting temperatures in both generations suggests the presence of other species than CO2. However, Raman analyses did not detect any species other than CO2 (i.e. CH4, N2, H2, CO, H2S). The melting point depression is not due to Ar or admixtures with noble gases, as only a few ppm Ar were detected in the fluid. The Ar-40/Ar-36 in the inclusions is 359, similar to vesiculated basalts from Loihi Seamount, Hawaii. Early inclusions were formed during pyroxenite equilibration processes that occurred during isobaric cooling in the mantle; they are most likely related to the crystallization of pyroxenite veins at a depth of almost-equal-to 55 km (17 kb). We suggest that solute-rich CO2 +/- H2O fluids coexisted with a compositionally evolved, volatile-rich residual silicate melt. These fluids migrated into the lherzolites and may have been responsible for the metasomatic enrichment in LREE and Na that is observed in the mantle below Oahu. Late carbonic inclusions were formed during the ascent of nodules from a depth of almost-equal-to 50 km. They resulted from the trapping of the host magma with an immiscible carbonic fluid phase

Clinopyroxene phenocrysts and ultramafic nodules in the “Ancient Alkaline Lavas” of Mount Etna contain melt and fluid inclusions which represent immiscible trapping of basaltic melt and CO2. Inclusions consist of glass + vapor (CO2) hosted by clinopyroxene with kaersutite, magnetite, spinel and apatite daughter minerals (type I), and liquid (CO2) + vapor (CO2) + glass secondary inclusions (type II) with highly variable fluid/glass ratios. Electron-microprobe investigations on type I melt inclusions indicate a glass of trachitic composition, with extremely high chlorine contents (0.5–1 wt.%), which we believe evolved from an initial melt composition of an alkali-basalt. Homogenization temperatures (Th) (n=128) of type II CO2 + glass inclusions display a bimodal fluid density distribution, with high-density (0.61–0.75 g/cm3) CO2 fluids in the nodules, and low-density (0.23–0.61 g/cm3) CO2 fluids in the phenocrysts. A two-step degassing process is proposed with high-density immiscible CO2 fluids, formed at pressures of about 4.3 kbar. The density distribution suggests interaction events between nodules, ascending lavas, and fluid phases, with a peak around 3.5 kbar. A second generation of lower-density CO2 is recorded around 2.8 kbar, most likely prior to eruption.