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Trace elements were measured in soil and groundwater collected within the Fornaci di Barga urban area (Serchio River Valley, Tuscany, Italy), a territory that integrates natural assets with touristic vocation, impacted by long-lasting metallurgical activity. Epidemiological studies highlighted that the area surrounding the industrial plants is characterized by a persistent excess of diseases, attributed to heavy metal pollution. Soils were taken in school gardens, public parks, sport grounds and roadsides. The results indicate that Cu, Zn and Cd represent the main contaminants in surface soil, likely originated by deposition of airborne particulate matter from metallurgical activity. Risk assessment considering soil ingestion and dermal contact exposure routes revealed that the cadmium Hazard Quotient approaches unity for children, and the cadmium risk-based concentration obtained by combining exposure information with toxicity data is only slightly lower compared with the cadmium maximum concentration actually measured in soil. Groundwater does not show evidence of trace metal contamination, suggesting that the migration of contaminants from soil to subsurface is a slow process. However, assessment of the possible interconnections between shallow and deep-seated aquifers requires monitoring to be continued. The obtained results highlight the possible link between space clusters of diseases and metal concentration in soil.

An abandoned open green space in the urban setting of the Municipality of Pisa (Tuscany, Italy) has been designed for renewal to foster the development of recreational activities and improve the lives of the surrounding communities. However, the geochemical site characterization revealed Pb, Cu, Zn and Hg concentrations in the soil exceeding the thresholds imposed by Italian regulations for residential use. Pb, Cu and Zn contents likely reflect the effects of urban vehicle traffic, while Hg contamination represents the legacy of a past artisanal tannery that used Hg(II)-chloride in leather processing in the mid-1900s. Mercury is widely distributed in the area, with the highest concentration in the uppermost soil layer, and reaching about 170 mg/kg in the common dandelion rhizosphere. Chemical extractions and thermal desorption experiments have indicated that most Hg is in the elemental free and matrix-bound fraction, with a possible minor amount (less than 4 wt%) of HgS and negligible methylated forms (0.1 wt%). The data suggest that soil processes could reduce Hg2+ to volatile Hg0. Mercury in groundwater, hosted in a shallow aquitard in the area, was below 0.2 µg/L. However, the presence of chloride in groundwater might result in the formation of Hg stable aqueous complexes, increasing Hg release from solids. Future water quality monitoring is hence recommended. The risk assessment highlighted that mercury in soil carries a risk of non-cancerous effects, in particular for children, posing the basis for management planning.

One of the major challenges for the sustainable development of the federal capital territory of Abuja (Nigeria) is related to the access to safe fresh water resources. This area lies within the drought prone parts of the Sahel region. As in many regions of the world there has been growing competing demands for fresh water as a result of population growth and groundwater quality degradation. In this context, the paucity of data and in depth knowledge of aquifer features and groundwater flow makes groundwater management even more complex, with a severe impact on access to safe water resources for the local populations. To address this challenge, the purpose of the presented research is to generate information on aquifer settings and its vulnerability and on the qualitative and quantitative assessment of the available groundwater resources. Remote sensing and GIS were applied to improve the available information on groundwater resources of Abuja. Fundamental information such as recharge rate, availability and vulnerability of groundwater to pollution was determined. Aquifer vulnerability zones were delineated using the DRASTIC model by integrating layers of depth to groundwater, aquifer recharge, aquifer media, soil type, topography, impact of vadose zone and hydraulic conductivity. The study area covers about 8000km². The elevation ranges from 62 to 843m a.s.l. with the highest elevations at the North Eastern parts and the lowest elevations at the South Western parts of the study area. There are three soil types in the area, the silty clay, silt loam and clay with clay being the predominant soil type. The five major rock types in the area include migmatite gneiss, schist and metasediment, sandstone and river alluvium, granite and quartzite. The aquifer type is phreatic and the depth to groundwater ranges from 2.8 to 21.9 m. The high recharge areas occurred mostly in highly fractured areas covered with metasedimentary rocks, migmatite gneiss and sandstones. The groundwater vulnerability zones in the study area were grouped into four classes: High, moderate, low and very low. The highly vulnerable zones are the North Eastern parts of the study area covering most parts of Bwari and parts of the municipal council areas and also the Southern parts of the study area covering parts of Kuje and Abaji. They constitute the highly fractured areas covered with silt loam soil type. The very low vulnerable zones are the North Western and Central parts covering mostly Gwgwalada and Kwali areas. This study demonstrates that GIS and remote sensing techniques are efficient and cost effective tool for delineation of groundwater vulnerability zones. The information obtained will be used as a basis for a geochemical characterization of groundwater quality in the region with the overall goal of supporting new groundwater management plans in the region.

The present study deals with the geochemical changes observed along Nile Delta inner shelf sediments over a period of 20 years (1995–2015). Major, minor, and trace constituents as well as rare earth elements (REE) were investigated in the surface sediments collected from seven transects along the inner shelf on five years intervals. Geochemical composition of sediments in Nile Delta inner shelf exhibits continuous changes over time due to the depositional and sediment transport processes. The sediments are generally enriched with Fe and Ti oxides, as well as Ta, Nb, Y in comparison to the Upper Continental Crust (UCC). These alterations signify the impact of processes such as erosion and sediment transport, as well as the impact of anthropogenic interferences such as damming the Nile River Flow. The reduction of the sediment input from the Nile River has somehow altered the geochemical signature of the inner shelf sediments. The REE patterns indicate weathering in areas subjected to erosion, while trace elements and major oxides spatial and temporal distributions concentrate eastwards under the influence of the easterly sediment transport pattern. Nile Delta inner shelf presented a typical case for understanding the link between geochemistry and sedimentary processes in nearshore and deltaic systems.

The Sr-isotope systematics and trace element analysis were applied to vine and wine collected during the 2015 harvest from the Bosa vineyard, a high-altitude farm in the Apuan Alps UNESCO Global Geopark in Italy, in order to investigate the links with geology in vineyards facing with a hostile environment. The results indicate a correspondence between the 87Sr/86Sr ratio in wine and must [87Sr/86Sr = 0.70843(1) and 0.70846(1), respectively] and the NH4OAc extractable Sr from soil [87Sr/86Sr = 0.70847(1)]. However, detailed investigations reveal that Sr-isotope data on grape juice collected in different vines vary in the range between 0.70833(1) and 0.70844(1), reflecting a small-scale vineyard variability and indicating that the root system explores heterogeneous soil resources for nutrient uptake. Grape seeds and stems from one single vine both show identical 87Sr/86Sr of 0.70820(1), significantly lower with respect to corresponding juice [87Sr/86Sr=0.70844(1)]: this finding is unexpected and reflects the uptake from isotopically different reservoir during the evolved dynamic of vine and fruit development. In particular, the lower 87Sr/86Sr ratio is attributed to the minor contribution of an unradiogenic carbonate component. These effects, however, do not mask the existing isotopic relationship between soil and wine at the vineyard scale. Trace elements in wine show a characteristic pattern that roughly mimics bedrock, suggesting a minor role of bedrock chemical weathering in developing the soil profile. Relatively high Fe and Mn contents are measured in wine, inherited from bedrocks, and high Zn, possibly applied to grapevines. Elements that are considered potentially toxic (As, Cd, Cu, Pb, Zn) are below the maximum acceptable limits established by OIV. Despite preliminary, these data represent the first characterization for traceability of the high-altitude Bosa vineyard, giving some track of weathering and elemental availability in a particular microclimate setting and underlying the link between bedrock geology and element uptake in vines at high elevations with respect to valley grown grapes.

This paper provides a case-study analysis on a thallium contamination related to the past activity in the dismissed mining sites of Monte Arsiccio and Pollone (Lucca Province, Tuscany, Italy). This site has received a lively public attention in recent times, after the finding of thallium at concentration of concern in drinkable waters, far exceeding the U.S. EPA threshold of 2 μg/L. Already published studies, plus original data, focusing on the different aspects of this case study are here reviewed highlighting how past-mine wastes can affect a whole eco-system, potentially causing adverse health effects in the population living in the area via environmental exposure. After a brief introduction on the mining activity in Tuscany (Section 1), the paper focuses on the geochemical processes behind the release of thallium in the area subject of the study (Sections 2–4), the status of its contamination in different ecological compartments (Sections 5–9) and the exposure of the local inhabitants (Section 10). As final remarks, considerations about possible health impacts are presented. The aim is to contribute to the proactive detection of environmental threats mainly related to thallium hazard and past mining activities, in order to prevent negative impacts to the ecosystem and human health, and to contribute in planning mitigation requirements.

The Triassic alkaline basaltic rocks (TABR) of North Kamarbon are located in Central Alborz, which is regarded as the northern part of the Alpine-Himalayan orogenic belt. Fractional crystallization does not appear as a major process in the genesis of TABR while different degree of partial melting may be regarded as the main process, based on petrography and geochemistry studies. The geochemical characteristics of TABR are in conflict with a substantial involvement of continental crust or crustal contamination. High (La/Yb)N and (Dy/Yb)N ratios, along with other geochemical features, in the TABR magma, suggest an asthenospheric origin, with low degree of partial melting of a garnet-bearing mantle sources. Enrichment patterns of LILE (Ba, Sr and Th), HFSE (Nb, Ta and Zr) and P, and depletion at HREE (Yb, Lu) are similar to what observed for OIB or intraplate alkaline magmatic rocks. The Sr and Nd isotopic ratios range from 0.70448 to 0.70522 and from 0.51269 to 0.51280, respectively, suggesting time-integrated slightly depleted magma sources. The data indicate that the evolution of TABR could be related to the rifting basin, in Late Triassic, which caused their development by upwelling and decompressional melting of an asthenospheric mantle, without a major involvement of subcontinental lithospheric mantle or crustal contamination. Keywords: Mantle source, Rifting basin, Central Alborz, Iran

The late Miocene Pisco Formation of Peru is an outstanding example of richness and high-quality preservation of fossil marine vertebrates. In order to reconstruct the fossilization path, we present new textural, mineralogical and Sr-isotope data of diagenetic minerals formed in correspondence of fossil specimens such as marine vertebrates and mollusks. These fossil specimens were found at Cerro los Quesos, in the Ica Desert, within the diatomaceous strata of the Pisco Formation. Dolomite, gypsum, anhydrite and Mn minerals are the main phases found, while the calcium carbonate originally forming the mollusk valves is replaced by gypsum. An early formation of dolomite and of Mn minerals, triggered by the modifications of the geochemical environment due to organic matter degradation, is suggested by the textural relationships and is confirmed by the Sr isotopic ratio of dolomite, which agrees with that of seawater at the time of sedimentation. Instead, gypsum Sr isotopic ratios indicate a pre-Miocene seawater-derived brine circulating within the sedimentary sequence as a source for Sr. Oxidation of diagenetic sulfide causing a lowering of the pH of porewater is proposed as an explanation for Ca-carbonate dissolution. The diagenetic chemical environment was, nevertheless, favorable to bone preservation.

Acid mine drainages (AMD) have adversely affected the southern Apuan Alps (northern Tuscany, Italy). The study particularly focuses on the Baccatoio stream, which receives AMD from the abandoned Pollone and M. Arsiccio mines. The mine waters have an average pH of 2.2 and contain potentially toxic elements (PTE) at concentrations that exceed the Italian regulatory threshold for Al, Fe, Mn, Cu, Zn, As, Ni, Co, Cd, Sb, Pb, and Tl. The AMD flow directly into the stream, severely contaminating it. Downstream of the mined areas, the pH increases and most PTE (especially Fe, Al, As, and Pb) are readily scavenged from the stream waters by precipitation and/or adsorption. However, Tl, which peak at 1000 µg/L in the AMD, behaves almost conservatively along the stream flow path, undergoing only dilution, and remains at or above the concentration of concern of 4 µg/L almost to the coastline, before sharply decreasing to 0.5 µg/L where seawater is encountered. Since the stream water was locally used for irrigation, these observations may have important environmental and public health consequences in such a densely populated area.

The origin of a resurgent hexavalent chromium contamination in groundwater from a phreatic aquifer in the Friuli Venezia Giulia Region plain was investigated by chromium isotopic systematics. The area underwent a severe Cr(VI) contamination by industrial effluents in 1997, when Cr(VI) concentration in groundwater reached 4500 µg/L. In subsequent years the contamination naturally attenuated, totally disappearing in 2003. A renewal of water contamination was observed in 2008, Cr(VI) reaching 1560 µg/L. The δ53Cr value in groundwater and extracts from sediments was measured in 2009-2011, and it ranges between -3.21 and +0.21‰ and between -4.71 and +1.26‰, respectively. Due to the lack of geogenic Cr-sources, these data are interpreted as evidence of the subsequent oxidation through Mn-oxides of the Cr(III) hosted in the aquifer and originated by the reduction of the original industrial chromates. Cr(III) is characterized by negative δ53Cr, starting from the δ53Cr value around zero of Cr(VI) in industrial effluents. Oxidation liberates soluble Cr(VI) which is transported by groundwater and permeated soils. The complex Cr-isotopic vs. concentration distribution reflects both the new Cr(VI) reduction and dilution processes in the aquifer system. From an environmental point of view, the data raise concerns regarding the potential impact of past Cr(VI)-contamination.

Thallium is among the most toxic elements to humans. Environmental regulations of the European Community adopted by Italy pose a maximum concentration level for Tl in groundwater of 2 μg/L. However, at present drinkable water must not abide any concentration threshold for thallium and this element is not routinely monitored. In the past-mining area nearby the Valdicastello Carducci village (northern Tuscany, Italy), characterized by Tl-bearing ores, water from a spring that has been tapped for human consumption contains thallium in the range 4.3–27.8 μg/L. The challenge of this study is to highlight the mechanisms leading to Tl contamination in groundwater, by crossing hydrochemical and O-H isotopic data with hydrogeological information. We propose that the Tl-contamination in the spring results from a binary mixing that occurs within a karst system involving an uncontaminated Ca-HCO3 water (mainly interacting with limestone) and a component originated by the interaction of acid drainages (generated by the weathering of Tl-bearing mineral phases in the area) with dolomitic host rocks. In this process, most of the potentially toxic elements released during the weathering are scavenged by the carbonate neutralization of the acid plume due to adsorption onto the iron and manganese oxyhydroxides that formed during pH changes. Nevertheless, the aquifer has little or no attenuation capacity for thallium. Moreover, O-H isotopic data and hydrogeological constraints are compatible with a spring feeding mechanism related to a piston displacement effect.

The present paper deals with a field experiments on evaporite rock samples and groundwater investigations in the Quinis test site, a hamlet of the Enemonzo municipality in NE Italy, were sinkholes occurred in the past and are still occurring causing severe damage to the existing infrastructures. The area is characterised by a Carnian evaporitic bedrock made of gypsum and anhydrite mantled by alluvial and colluvial deposits. In order to evaluate the loss of weight and volume of the subcropping evaporites as responsible for sinkholes, a field-experiment was carried out. Inside seven piezometers, at different depths, evaporitic rock samples were exposed to the naturally occurring variable climatic conditions such as degree of humidity, different air flow and hydrodynamic. The rock samples were installed at the beginning of April 2017 in the dry sections of piezometric tubes, in the vadose zone and in the phreatic zone. Data related to water level fluctuations were recorded by using data-logger devices and highlight significant changes in the water table. After 13 months of data recording (May 2018), rock samples were removed, reweighted and the volume loss measured. In addition, water from piezometer-experiment, representative of the groundwater circulation, were collected at different depths. The obtained results indicate that rock sample reduction is dependent on the hydrological regime and water chemistry and not on the number of days during which the samples remained submersed. In particular, the water geochemistry highlights the possible role in gypsum/anhydrite dissolution due to NaCl water admixing in a complex scenario. In additional, the geochemical data highlight the occurrence of some potentially toxic elements (As, Fe, Mn) at concentrations of concern in some water. This approach represents a novel contribution in the study of karst hazard in evaporites adding a tile to the knowledge of the fast evolutionary processes which cause sinkhole formation.

The oxygen and hydrogen isotopic composition of stream water, springs, groundwater tapped from irrigation wells and acid mine drainages were determined during two different surveys in 2015 in an area highly impacted by past-mining activity of Apuan Alps (Italy), as a guidance on good practices for water management. The isotopic local meteoric water line (LMWL) was built by monthly collecting rainwater between 2014 and 2018, given by delta D = 7.02 +/- 0.35 x delta O-18 + 8.54 +/- 2.89. The obtained results indicate that acid mine drainages (AMD) are supplied by freshwater from karst systems which flow throughout the post-mining workings. Such waters contaminate by interactions with sulfides (pyrite) that remained unmined in the ore-bodies. During rainstorms, infiltration rainwater displaces water ponding within mine, sharply increasing the outflow rate of highly-contaminated AMD. Acidic drippings in tunnels show an isotopic shift in both delta O-18 and delta D values attributable to pyrite oxidation and Fe hydrolysis. The data reveal that karst-springs represents the primary supply for the stream. The isotopic data also reveal that waters flowing in the bedrock carbonate aquifer represent the main feeding component for the overlying alluvial aquifer tapped by wells. The prevailing transfer of clean freshwaters from the carbonate aquifer towards the alluvial aquifer system mitigates the possible influence of contaminated water from stream seepage. However, these observations require a monitoring program on water quality to be established.

A mini review of the toxicity of Thallium (Tl) at low doses is herein presented. Thallium has severe toxicity. Although its acute biological effects have been widely investigated and are well known, its biological effects on human health and in cell cultures at low doses (

The abandoned mining area of Valdicastello Carducci (Tuscany, Italy) is characterized by the massive presence of thallium in the acid mine drainages and in the valley stream crossing the region. We previously found that Tl(III), generally considered the less stable oxidation state of thallium, is present both in the stream and in tap water distributed in the area, whereas acid mine drainages only contain Tl(I). These findings posed some concern related to the reactivity and dispersion of this toxic element in the environment. Since the valence state of thallium determines its toxicity, distribution and mobility, the study of thallium redox speciation appears crucial to understand its environmental behaviour. In this work, water samples collected from the mine drainages and the contaminated stream were adopted as model to study the distribution of aqueous Tl(I)/Tl(III) as a function of light exposure and solution properties and composition. The influence of three light sources and organic acids was evaluated. Thallium speciation was also assessed in tap water after treatment with common oxidizing agents, and in the rust crust collected from the public waterworks.

The analysis of trace metals and metalloids, and the Sr-isotopic systematics were applied to 16 must samples from vines growing in the Sesia Val Grande Supervolcano UNESCO Global Geopark in the northern Piedmont Region (Italy), a land worldwide famous for the production of quality Nebbiolo-based red wines. Twenty-four elements were measured in each sample with inductively coupled plasma-mass spectrometry (ICP-MS). The results indicate a wide variability in trace element concentration in musts from the different vineyards. In particular, Rb and Sr reach their maximum at 5110 and 694 µg L−1, respectively, reflecting the geological nature of the magmatic bedrocks. Fe, Cu, Pb and Ba concentrations reach 3118, 1200, 130 and 720 µg L−1, respectively, suggesting a source from iron oxide, Pb–Zn and Ba ores associated to the volcanic activity. The 87Sr/86Sr ratio is in the range 0.711608–0.718160, showing a highly radiogenic signature which is uncommon in must/wine. This is consistent with the high 87Sr/86Sr isotopic ratio of the old rhyolitic bedrocks. Furthermore, the 87Sr/86Sr ratio in musts linearly correlates with the corresponding 87Rb/86Sr ratio, reflecting the Rb and 87Sr release from primary minerals during pedogenesis and matching the initial 87Sr/86Sr ratio of the parent bedrocks magmatic reservoir, thus assuming importance for authenticity assessment.

Glera vineyards from the Prosecco wine district in northern Italy have been characterised in terms of the 87 Sr/ 86 Sr isotope-ratio of musts from the 2010, 2011 and 2012 vintages, coupled with the isotopic analysis of Sr in the labile fraction of the soils of provenance. For a single vineyard, detailed Sr isotopic analyses were carried out in sequentially extracted soil fractions at three different depths, and in the grape components (skin, seeds, must and stem), in order to verify the lack of Sr isotopic fractionation within the plant. The 87 Sr/ 86 Sr in must, seeds and stem overlaps within experimental uncertainties; skins are shifted towards a lower Sr isotopic composition. A large range of Sr isotopic compositions ( 87 Sr/ 86 Sr between 0.70706 and 0.71215) characterizes musts from the different vineyards, notwithstanding the relatively limited extension of the investigated geographic area. A statistically significant correspondence between the soil labile fraction and must is observed.

While monitoring the physico-chemical characteristics, trace elements and O-H-Sr-B isotopic data were obtained in superficial waters from a number of irrigations canals and ditches in the Ravenna coastal plain, in order to highlight the cycling of potentially toxic elements and the different sources of the solutes. Surveys were conducted during March and July 2008, and considered as representative of the waters in winter and summer, respectively. In summer, the water mass balance in the network is mostly controlled by the ingression of freshwaters from the Canale Emiliano Romagnolo (CER). The O-H isotopic data indicated that, in winter, waters are primarily recharged from Apennine catchments and undergo evaporation to different extents. The boron isotopic signature indicates the important role played by the marine component. A major seawater contribution was evidenced in canals close to the coastline; however, the process controlling the origin of dissolved boron is not solely related to direct mixing with sea water but comprises an additional source probably related to water-soil exchanges and boron of marine origin leaching, owing to the prolonged exposure of alluvial sediments to sea water. An additional boron contribution from the agricultural practice was is also evidenced. Calculation based on the conservative behaviour of chloride ions indicated that in canals and ditches not directly connected with the sea up to the 80% of the Sr budget did not originate from seawater, indicating a source from Al-silicate minerals and upporting the hypothesis of significant soil-water interactions and chemical exchanges. The positive correlation between pH and dissolved oxygen in winter waters is likely to reflect CO2 consumption during algal photosynthesis, favouring the in-situ generation of colloidal particles due to the oxidative precipitation of ferric iron oxy-hydroxides and probably small carbonate particles able to adsorb trace metals on their surface and contribute to the ecosystem dynamics facilitating the transport of metals and affecting their bio-availability and cycling. During summer, the input of freshwater from CER lowered the concentration of most ions and became superimposed to the evaporation-precipitation-exchange cycle, possibly dispersing the colloidal particles which could act as pollutant carriers and enhancing flocculation and precipitation, scavenging trace metals into the sediments.

In this work we present an advantageous method for the simultaneous separation and detection of Tl(I) and Tl(III) species through ion chromatography coupled with on-line inductively coupled plasma - mass spectrometry. Chromatographic separation between Tl(III) and Tl(I) was achieved in less than two minutes. The method was validated by recovery experiments on real samples, and by comparing the sum of the concentrations of individual Tl species with total thallium values obtained from continuous flow ICP-MS. The experimental procedure offers an accurate, sensitive and interference-free method for Tl speciation at trace levels in environmental samples. This allowed us to investigate the Tl speciation in acid mine drainages (AMD), surface waters and springs in a mining catchment in Valdicastello Carducci (Tuscany, Italy), where severe Tl contamination ad been evidenced previously. This study shows for the first time that Tl(III), in addition to Tl(I), is present in considerable amounts in water samples affected by acid mining outflow, raising the question of the origin of this thermodynamically unstable species.

The Raibl mine (Cave del Predil village, northern Italy) belongs to the Pb–Zn minerogenetic district in the southeastern Alps, hosted in Middle Triassic carbonates. The drainage water quality reflects the high acid-buffering capacity of the carbonate rocks, which controls the mobility of most metals. In particular, Fe is non-detectable in solution, having formed hydrous-oxides precipitates. Molybdenum, Ni, Zn, Cd, Pb, and Tl are present, and the Pb, Tl, and Zn concentrations sometimes exceed the Italian regulatory thresholds. Thallium concentrations substantially exceed the 2 µg/L limit at some sampling stations, ranging between 12 and 30 µg/L in the mine drainage, and reaching 5 µg/L downstream of the mine site, despite strong dilution. The data indicate that Tl behaves almost conservatively and is not significantly scavenged by the Fe precipitates. The elevated Tl represents a potential risk for the stream ecosystem. Although Tl is not regulated in drinking water in Italy or the European Community, its distribution in natural waters may help to determine if health actions should be taken.

The alkali-basalt and basaltic trachy-andesites volcanic rocks of south Marzanabad were erupted during Cretaceous in central Alborz, which is regarded as the northern part of the Alpine-Himalayan orogenic belt. Based on petrography and geochemistry, en route fractional crystallization of ascending magma was an important process in the evolution of the volcanic rocks. Geochemical characteristics imply that the south Marzanabad alkaline basaltic magma was originated from the asthenospheric mantle source, whereas the high ratios of (La/Yb) N and (Dy/Yb) N are related to the low degree of partial melting from the garnet bearing mantle source. Enrichment pattern of Nb and depletion of Rb, K and Y, are similar to the OIB pattern and intraplate alkaline magmatic rocks. The K/Nb and Zr/Nb ratios of volcanic rocks range from 62 to 588 and from 4.27 to 9 respectively, that are some higher in more evolved samples which may reflect minor crustal contamination. The isotopic ratios of Sr and Nd respectively vary from 0.70370 to 0.704387 and from 0.51266 to 0.51281 that suggest the depleted mantle as a magma source. The development of south Marzanabad volcanic rocks could be related to the presence of extensional phase, upwelling and decompressional melting of asthenospheric mantle in the rift basin which made the alkaline magmatism in Cretaceous, in northern central Alborz of Iran.

A seismic swarm characterized by a Ml = 5.9 mainshock occurred in the Po Valley, northern Italy, in 2012. The area has been studied for active compressional tectonics since the beginning of the twentieth century. A variety of geophysical and geochemical parameters have been utilized with the purpose of identifying possible precursory signals. This paper considers groundwater level data and geochemical data both in groundwaters and in gases. All considered parameters have led to the conclusion that possible long and medium precursory trends have been identified in geofluids. No short-term precursors have been clearly identified. Hydrogeological and geochemical monitoring could be more effectively utilized in a different geological context, and seismic hazard reduction procedures could benefit from geofluid monitoring.

A geological study evidenced the presence of thallium (Tl) at concentrations of concern in groundwaters near Valdicastello Carducci (Tuscany, Italy). The source of contamination has been identified in the Tl-bearing pyrite ores occurring in the abandoned mining sites of the area. The strongly acidic internal waters flowing in the mining tunnels can reach exceptional Tl concentrations, up to 9000μg/L. In September 2014 Tl contamination was also found in the tap water distributed in the same area (from 2 to 10μg/L). On October 3, 2014 the local authorities imposed a Do Not Drink order to the population. Here we report the results of the exposure study carried out from October 2014 to October 2015, and aimed at quantifying Tl levels in 150 urine and 318 hair samples from the population of Valdicastello Carducci and Pietrasanta. Thallium was quantified by inductively coupled plasma - mass spectrometry (ICP-MS). Urine and hair were chosen as model matrices indicative of different time periods of exposure (short-term and long-term, respectively). Thallium values found in biological samples were correlated with Tl concentrations found in tap water in the living area of each citizen, and with his/her habits. Thallium concentration range found in hair and urine was 1-498ng/g (values in unexposed subjects 0.1-6ng/g) and 0.046-5.44μg/L (reference value for the European population 0.006μg/L), respectively. Results show that Tl levels in biological samples were significantly associated with residency in zones containing elevated water Tl levels. The kinetics of decay of Tl concentration in urine samples was also investigated. At the best of our knowledge, this is the first study on human contamination by Tl through water involving such a high number of samples.

The major, trace (including rare earth) element abundances, and Sr-Nd-Pb isotopic compositions, have been analysed for andesitic basalt and andesitic sills and lavas of the Jurassic Ferrar Magmatic Province, Prince Albert Mountains, Antarctica. The typical “crustal signature” of the Ferrar magmatism, characterized by relatively high SiO2, LREE and LILE contents in these samples, is associated with high 87Sr/86Sr and low 143Nd/144Nd. Systematic correlations of major and trace elements indicate that fractional crystallization was important. However, increases in incompatible elements are positively correlated with initial 87Sr/86Sr, suggestive of crustal assimilation processes. The observed correlations between initial 87Sr/86Sr and LREE enrichments have been modelled by an AFC process, starting from the least evolved sample and assuming the compositions of the orthogranulites of Victoria Land as contaminants. The REE patterns of the least evolved Ferrar rocks approach those of E-type MORB, differing only by higher LREE/IREE. The enrichment in LREE, accompanying high initial 87Sr/86Sr, 207Pb/204Pb and low 143Nd/144Nd compared with E-type MORB, can be explained by interaction of “primary Ferrar basalt” with crystalline basement. We propose a petrological model whereby Ferrar magmas were generated through high degrees of melting of an E-type MORB mantle source, and subsequently these “primary” melts underwent AFC processes inheriting a crustal signature. The Sr-Nd-Pb isotopic compositions required by the AFC model for the primary Ferrar basalt are similar to those of the Dupal signature of the oceanic basalts of the Southern Hemisphere (Hart 1984). Transantarctic Mountains would have been located inside the Dupal anomaly in pre-Gondwana dispersion times.

The major element chemistry and SrNd isotope composition of three basaltic glasses and two whole rock samples dredged from the Nereus Deep, in the central Red Sea, were used to constrain the nature of the magmatism in the Nereus axial valley. The glass and whole rock compositions show the tholeiitic character of magmas and their affinity with MORB. The chemical composition of the most magnesian glass (mg# = 69.9) would suggest an origin from a melting event in the mantle at a pressure in the range 8–10 kbar. Magma differentiation modelling using the major element chemistry of the more evolved glasses indicates mineral-melt equilibration at moderate pressure, followed by most of the fractionation under low pressure conditions. The observed Ti content and Sr isotope composition suggest the occurence of additional processes besides fractionation, and could reflect different degrees of partial melting of a slightly heterogeneous mantle source. The SrNd isotope composition reveals the time-integrated depleted nature of the mantle, and overlaps the fields of MORB and basalts from the southern Red Sea axial ridge. The Sr isotope data on glasses resemble more closely the compositional range reported for the Indian Ocean ridges, and suggest a dominant asthenospheric source, with minor enriched components.

Geochemical investigations were carried out to define the origin of the low- to moderate-temperature thermal waters feeding the Monfalcone springs in northern Italy. Chemical data indicate that waters approach the composition of seawater. Mixing processes with cold low-salinity waters are highlighted. The δ18O and δD values are in the range −5.0 to −6.4 ‰, and −33 to −40 ‰, respectively, suggesting the dilution of the saline reservoir by karst-type freshwaters. A surplus of Ca2+ and Sr2+ ions with respect to a conservative mixing is ascribed to diagenetic reactions of the thermal waters with Cretaceous carbonates at depth. The measured Sr isotopic composition (87Sr/86Sr ratio) ranges between 0.70803 and 0.70814; after correction for the surplus Sr, a 87Sr/86Sr ratio indicating Miocene paleo-seawater is obtained. The dissolved gases indicate long-lasting gas–water interactions with a deep-originated gas phase of crustal origin, dominated by CO2 and marked by a water TDIC isotopic composition in the range −5.9 to−8.8 and helium signature with 0.08 < R/Ra < 0.27, which is a typical range for the crust. A possible scenario for the Monfalcone thermal reservoir consists of Miocene marine paleowaters which infiltrated through the karstic voids formed within the prevalently Cretaceous carbonates during the upper Eocene emersion of the platform, and which were entrapped by the progressive burial by terrigenous sediments.

Transitional basalts of the Treinta y Tres region intrude late Proterozoic granites in northeast Uruguay. The age of the swarm is assumed to be close to 750 Ma. Major and trace geochemical diagrams indicate gabbro type fractionation, which is supported by MPR plots. In comparison to the Florida and Nico Perez suites, the Treinta y Tres swarm is enriched in Ti, P, Zr and Sr and depleted in LILE and REE. These features and the Sro and Ndo isotope values are discussed in terms of source heterogeneity and crustal contamination. The geochemical characteristics do not support crustal contamination. The Treinta y Tres suite is better explained by a source affected by two melting episodes. The dikes were originated from the latter melting, which occurred in a an isotopically heterogeneous source. Diagrams related to several incompatible elements ratios indicate that the mantle source of Uruguaian dikes and of continental basalts of Brazil have similar geochemical features since Early Proterozoic up to Mesozoic.

A periodic sampling of the groundwaters and dissolved and free gases in selected deep wells located in the area affected by the May-June 2012 southern Po Valley seismic sequence has provided insight into seismogenic-induced changes of the local aquifer systems. The results obtained show progressive changes in the fluid geochemistry, allowing it to be established that deep-seated fluids were mobilized during the seismic sequence and reached surface layers along faults and fractures, which generated significant geochemical anomalies. The May-June 2012 seismic swarm (mainshock on May 29, 2012, M 5.8; 7 shocks M >5, about 200 events 3 > M > 5) induced several modifications in the circulating fluids. This study reports the preliminary results obtained for the geochemical features of the waters and gases collected over the epicentral area from boreholes drilled at different depths, thus intercepting water and gases with different origins and circulation. The aim of the investigations was to improve our knowledge of the fluids circulating over the seismic area (e.g. origin, provenance, interactions, mixing of different components, temporal changes). This was achieved by collecting samples from both shallow and deep-drilled boreholes, and then, after the selection of the relevant sites, we looked for temporal changes with mid-to-long-term monitoring activity following a constant sampling rate. This allowed us to gain better insight into the relationships between the fluid circulation and the faulting activity. The sampling sites are listed in Table 1, along with the analytical results of the gas phase. […]

High arsenic (As) concentrations, >900 μg/L, were measured in Ca–Mg–SO4 waters from springs and drainages in the village of Pesariis in the Carnic Alps (NE Italy). Oxidation of the outcropping arsenian marcasite ore deposits of the area is proposed as the mechanism for As release into oxygenated waters during runoff. Nevertheless, the limited extension of the ore deposit and the relatively low As content of the mineralization suggest that sulfide weathering might not be the only process responsible for the highest As concentration in groundwaters. An additional mechanism involves As adsorption onto ferric iron particulate during oxidation, the drawdown in reducing environment at depth during water infiltration, and the release of ferrous iron and sorbed arsenic to the water columns by reductive dissolution of hydrous ferric oxides (HFO). This yields the observed Fe–As correlation. Newly formed HFO precipitates when groundwaters discharge to aerated conditions, leading to the removal of As, which strongly partitions into the iron-rich sediments, adsorbed onto the surface of amorphous Fe2O3·xH2O. The calculated and measured As concentration in sediments exceeds 10% by weight. Furthermore, geochemical and isotopic data indicate that the As-rich reservoir partly mixes with shallower aquifers, commonly tapped for drinking supply, representing a natural hazard for inhabitants.

Water samples from cold and geothermal boreholes, hot springs, lakes and rivers were analyzed for δD, δ18O and 87Sr/86Sr compositions in order to investigate lake water–groundwater mixing processes, water–rock interactions, and to evaluate groundwater flow paths in the central Main Ethiopian Rift (MER) of the Ziway–Shala basin. Different ranges of isotopic values were recorded for different water types: hot springs show δ18O −3.36 to +3.69 and δD −15.85 to +24.23, deep Aluto-Langano geothermal wells show δ18O −4.65 to −1.24 and δD −12.39 to −9.31, groundwater wells show δ18O −3.99 to +5.14 and δD −19.69 to +32.27, whereas the lakes show δ18O and δD in the range +3.98 to +7.92 and +26.19 to +45.71, respectively. The intersection of the Local Meteoric Water Line (LMWL: δD = 7 δ18O + 11.2, R2 = 0.94, n = 42) and the Local Evaporation Line (LEL: δD = 5.63δ18O + 8, n = 14, R2 = 0.82) was used to estimate the average isotopic composition of recharge water into the basin (δD = −5.15 and δ18O = −2.34). These values are depleted if compared with the modern-day average precipitation, presumably indicating paleo-groundwater components recharged during previous humid climatic phases. The measured stable isotope values indicate that the geothermal wells, some of the hot springs and groundwater wells mainly consist of meteoric water. The Sr isotopic signatures in all waters are within the range of the Sr isotopic composition of the rift basalts and rhyolites. The variability of Sr isotopic data also pinpoints complex water–rock interaction and mixing processes in groundwater and surface water. The 87Sr/86Sr ratio ranges from 0.70445 to 0.70756 in the hot springs, from 0.70426 to 0.70537 in two deep geothermal wells, and from 0.70673 to 0.70721 in the rift lakes Ziway, Langano, Shala and Awasa. The radiogenic composition recorded by the lakes indicates that the input water was predominantly affected by progressive interaction with rhyolitic volcanics and lacustrine sediments. There is a change in MER water composition between the recharge-infiltration zone (surrounding highlands) and the discharge areas, from depleted δD, δ18O and less radiogenic Sr isotope compositions to enriched δD, δ18O and more radiogenic Sr isotope compositions. Isotope analyses are therefore useful in providing further understanding of the hydrologeological processes occurring within a productive aquifer and the surface water system.

The state of water in volcanic glasses separated from pumices and shards of alkali-trachyte composition from the Agnano- Monte Spina eruption (4.1 ka) in the Phlegrean Volcanic District (South Italy) has been investigated by 1H Magic Angle Spinning Nuclear Magnetic Resonance spectroscopy. The surface analysis of pumice glasses indicates that they correspond to a highly vesiculated, disordered foam characterized by several generations of vesicles both of sub-spherical and strained shape, suggesting a sudden increase of the melt structural relaxation time while bubbles were still deforming. Shards, characterized by low vesicularity, are typically composed of angular or sub-rounded clasts of glass, the latter showing, in some cases, evidence of surface pitting. The 1H resonance patterns of shards can be fi tted in terms of isolated H2O molecules and OH groups. The shards with the highest water content and rounded shape, supposed to be the product of phreatomagmatic explosions, are characterized by the higher H2O/OH molar ratio (2.6), attributed to the interaction of the melt with external water. In the angular shard, previously interpreted as due to magmatic fragmentation, the molar H2O/OH ratio is significantly lower (0.7).

Alkaline rocks can be found in three major areas (northern, northeastern and central-eastern) of Eastern Paraguay. On die basis of geographic distribution and tectonic association, Livieres & Quade (1987) proposed inclu- sion of these outcrop areas different alkaline provinces: Alto Paraguay, Amambay and Central, respectively (Fig. 1). Presently, only the Central Province, clustering the largest number of occurrences, is the subject of systematic investigation. Available information on the Alto Paraguay and Amambay rocks is still scarce.

The Mesozoic magmatic activity in the easternmost part of NE Brazil (Ceara-Mirim) is mainly represented by two-pyroxene tholeiitic dykes; only few dykes have alkaline character. K/Ar ages and palaeomagnetism data indicate that Ceara-Mirim dykes are of Middle Jurassic (175-160 Ma) and Early Cretaceous (140-130 Ma) age. Both Middle Jurassic and Lower Cretaceous dykes have high incompatible-element concentrations and TiO2 with the lower contents generally confined to the Middle Jurassic dykes; rare tholeiitic dykes low in TiO2 and incompatible elements are present. Sr/1bNd isotopic and other chemical data do not support appreciable crustal contamination and in a 87Sr86Sr vs. 143Nd144Nd diagram almost all the dykes plot in a narrow area of the enriched quadrant of the “mantle array”. Tholeiitic and alkaline Ceara-Mirim dykes are related to different parent magmas probably originating by different degrees of melting of garnet-peridotite mantle sources characterized by distinct Sr/1bNd isotope compositions and small-scale chemical heterogeneities. Ceara-Mirim tholeiitic dykes show close mineralogical, chemical and isotopic similarities with the Lower Cretaceous high-TiO2 tholeiites from Maranhao (Sardinha intrusives) and Parana (Northern Province) basins. In general, chemical and Sr/1bNd isotope data for high- and low-TiO2 Brazilian Mesozoic tholeiites appear to be related to time-integrated enriched and depleted mantle components, respectively. Subcontinental mantle heterogeneity is believed to be due to variable “enriched” components related to “metasomatic” processes. The Ceara-Mirim Jurassic dykes correlate well in terms of composition and tectonic setting with the analogue tholeiitic dyke swarms from the Benue trough, and can be related to the opening of the Central Atlantic Ocean. The Lower Cretaceous Ceara-Mirim magmatic activity corresponds to the coeval one of the Benue trough and can be related to the early rifting events responsible for the opening of the Equatorial Domain of the South Atlantic whose oceanic crust formed between 120 and 100 Ma.

The first geochemical data showing the existence of an active degassing activity over a large seismically active sector of the Southern Alps (Friuli Region, NE Italy) are presented. The dissolved gases, helium and carbon isotopic systematics of 46 water samples taken from 13 sites running along E–W and NE–SW faults besides the natural degassing of a 5000 km 2 wide area are investigated. The chemical composition of the dissolved gases revealed that a CO 2 -rich gas phase feeds the local groundwaters. 3 He/ 4 He ratios ( R ) normalized to the atmospheric 3 He/ 4 He ratio (Ra = 1.39 × 10 − 6 ) and corrected for the atmospheric contamination ( R /Ra c ), range from 0.29 to 1 as a result of a two component (radiogenic and atmospheric) mixing. The δ 13 C values of total dissolved inorganic carbon (TDIC) ranging from − 15.28 to − 0.75‰ vs. PDB, show the occurrence of multiple gas–water interactions. The mixing between the atmospheric air and a crustal source and the gas–water interactions occurring at various extents appears to be the main control on the observed He–C systematics. The natural CO 2 degassing was evaluated by a soil gas survey carried out by a grid of about 100 measuring sites located over the area that generated destructive seismic sequences (e.g. the Gemona sequence of 1976; main shocks M6.4 of 6th May and M6.1 of 11th and 15th September). The results obtained show that a significant amount of crustal-originated gases are released over the continental area of Eastern Southern Alps. The evidence that carbon dioxide is associated with radiogenic-type helium denotes the lack of the mantle as primary energy and degassing source, highlighting the possibility that CO 2 is produced by thermo-mechanical processes occurring at seismogenic depth. The information provided here may be used to start up a long-term geochemical monitoring of this seismically active area and could be able to detect the modifications occurring to the circulating fluids to gain a better insight on the relationships between the fluids' geochemistry and the activity of the local seismogenic faults.

Major, trace element and isotopic data are reported for Hercynian granodiorites and tonalites from Capo Vaticano, Calabria, with the aim of clarifying the relationships between acidic and intermediate lithologies in orogenic intrusive suites. These granodiorites (SiO 2 = 70.5%–73.5%) are peraluminous, relatively depleted in Rb, U, Th, and Pb, and display a large variation in many geochemical and isotopic parameters. REE show fractionated, cross-cutting chondrite-normalized patterns with small but significant negative Eu anomalies. Initial (290 Ma) Sr and Nd, and present-day Pb isotope ratios are: ( 87 Sr 86 Sr ) 290 = 0.7105–0.7110 ; ( 143 Nd 144 Nd ) 290 = 0.51175–0.51221 ; 206 Pb 204 Pb = 18.35–18.50 ; 207 Pb 204 Pb = 15.64–15.76 ; 208 Pb 204 Pb = 38.51–39.03 . Pb isotope ratios determined for separated feldspars show similar 207 Pb 204 Pb and 208 Pb 204 Pb and higher 207 Pb 204 Pb ratios compared to the present-day values for the whole rock. The tonalites (SiO 2 = 57.6%–67.3%) are typically calc-alkaline in composition and most of them are weakly peraluminous. They display large heterogeneities in trace-element abundances, REE patterns and Nd and Pb isotope ratios, both between and within individual intrusive units. Sr, Nd and Pb isotopic compositions display a range of values close to that of the associated granodiorites ( 87 Sr 86 Sr ) 290 = 0.7099–0.7111 ; ( 143 Nd 144 Nd ) 290 = 0.51185–0.51224 ; 206 Pb 204 Pb = 18.31–18.56 ; 207 Pb 204 Pb = 15.65–15.72 ; 208 Pb 204 Pb = 38.41–39.59 . The obtained data indicate that the tonalites and granodiorites share many compositional features which point to a genetic linkage. Likewise, many petrological, geochemical and field data exclude the possibility that all the granodiorites derive from intermediate magmas by any common evolutionary process, such as crystal-liquid fractionation or assimilation-fractional crystallization (AFC), and point to a different genesis for the two rock types. An origin of the granodiorites by the mixing of two separate acidic melts, one of crustal anatectic origin and one probably derived from an intermediate magma by crystal/liquid fractionation or AFC, is suggested by the data presented. The tonalites appear to have been generated by interaction of a mafic magma with crustal end-member(s) with isotopic and geochemical signatures similar to those of the granodiorites. The large involvement of crustal material in the genesis of the Capo Vaticano granitoids is responsible for the many common compositional characteristics observed in the intermediate and acidic rocks. However, a contribution from mantle components is also indicated by petrological and geochemical data, as well as by the occurrence of mafic enclaves commonly present in the tonalites. Nevertheless, the geochemical and isotopic features of such a mantle component appear to be greatly diluted by a large quantity of crustal material involved in the genesis of the studied granitoids.

The Lower Cretaceous dykes of the Ponta Grossa Arch, the most important dyke swarms in Brazil, are associated with the flood basalts and rare acid flows of the northern Parana basin. The Ponta Grossa (PG) dykes are formed by two-pyroxene tholeiites and rare acid rocks. The basaltic dykes may be distinguished into two main groups: a dominant, high-TiO2 (> 2 wt.%; HTi) group and a subordinate, low-TiO2 (< 2 wt.%; LTi) group, characterized, for similar MgO content, by high and low incompatible-element contents, respectively. Most PG dykes do not show chemical and isotope evidence supporting important crustal contamination. PG dykes with (87Sr86Sr)0 < 0.7060 plot in the mantle array (ϵSr ≈ + 17 and ϵNd ≈ −3) and can be considered virtually uncontaminated. Intra-dyke chemical variations suggest that the normal or reverse differentiation trends may be related to pre-emplacement low-pressure differentiation processes. The important chemical differences between incompatible-element-poor and incompatible-element-rich basaltic dykes cannot be accounted for in terms of fractional crystallization, but are compatible with different melting degrees of a garnet peridotite mantle source, e.g. 9% and 20% melting for the HTi and LTi tholeiites, respectively. Field distribution of the magmatism, chemistry and Sr-Nd isotope compositions support that the PG dykes may be related to the flood volcanics of northern Parana, and not to those of the central and southern Parana. Paleomagnetic data indicate that PG dykes are younger than the Parana volcanics. All the results suggest that PG dykes were probably feeders of the stratoid volcanics erupted in northern Parana towards the continental margin and later eroded. Chemistry and isotopic data reveal that asthenospheric mantle components were not significant factors in the genesis of PG dykes. Dyke emplacement occurred during early phases of rifting and/or flexuring cutting flood volcanic suites.

In order to improve the microscopic understanding of the water–magma interaction process during explosive volcanism, volcanic glasses representative of deposits with sedimentological characteristics suggesting different water/melt ratios were studied by a combination of the nuclear magnetic resonance (NMR) and TIMS methods. The glasses were separated from pumices of two surge layers and one fallout bed of the Cretaio Tephra (Ischia Island, Italy), which is the product of an explosive eruption that occurred at Ischia in the second century BC. The 29Si CP–MAS NMR experiments indicate the occurrence of 1H–29Si dipolar couplings in glasses from the phreatomagmatic activity, suggesting the presence of hydrogen atoms in proximity of silicon atoms. This feature is not detected in the glass from the deposit of the magmatic explosion. 1H MAS NMR spectra reveal different peaks attributed to different hydrous species characterized by different motional properties. These include ‘rigid’ H2O groups isolated in the glass structure, more mobile water species and possibly structural hydroxyl groups. 1H MAS NMR spectra recorded after deuteration experiments of the glass at a temperature up to 300°C revealed that the exchange reactions of the D2O vapor with hydrogen were limited to the most mobile water species, possibly on vesicle surfaces or in channels. The hydrogen concentration linearly correlates with the 87Sr/86Sr isotope ratio in glasses, suggesting isotopic tracer exchanges between the Sr dissolved in the water vapor and the Sr in the silicon–oxygen network during hydration. It is proposed that the uprising melt interacted with a hydrothermal system of seawater-derived fluids, characterized by relatively high Sr isotopic composition.