Thallium contamination in the Raibl Mine Site stream drainage system (Eastern Alps, Italy)

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

Petrogenesis and mantle source characteristics of Triassic alkaline basaltic rocks of North Kamarbon, Northern Central Alborz, Iran

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, Ira

Cretaceous alkaline volcanism in south Marzanabad, northern central Alborz, Iran: Geochemistry and petrogenesis

Abstract 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

Evaporite Dissolution Rate through an on-site Experiment into Piezometric Tubes Applied to the Real Case-Study of Quinis (NE Italy)

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

Evaporite Dissolution Rate through an on-site Experiment into Piezometric Tubes Applied to the Real Case-Study of Quinis (NE Italy)

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 dierent depths, evaporitic rock samples were exposed to the naturally occurring variable climatic conditions such as degree of humidity, dierent 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 dierent 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

Trace Elements in Soil and Urban Groundwater in an Area Impacted by Metallurgical Activity: Health Risk Assessment in the Historical Barga Municipality (Tuscany, Italy)

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

Influence of environmental and anthropogenic parameters on thallium oxidation state in natural waters

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

Human exposure to thallium through tap water: A study from Valdicastello Carducci and Pietrasanta (northern Tuscany, Italy)

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 min- ing tunnels can reach exceptional Tl concentrations, up to 9000 μg/L. In September 2014 Tl contamination was also found in the tap water distributed in the same area (from 2 to 10 μg/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 1–498 ng/g (values in unexposed subjects 0.1–6 ng/g) and 0.046–5.44 μg/L (reference value for the European population 0.006 μg/L), respectively. Results show that Tl levels in biological samples were significantly associat- ed 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

Geochemical characterization of recent Nile Delta inner shelf sediments: Tracing natural and human-induced alterations into a deltaic system

Abstract 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

Organometallic rhodium(iii) and iridium(iii) cyclopentadienyl complexes with curcumin and bisdemethoxycurcumin co-ligands

A series of half-sandwich cyclopentadienyl rhodium(iii) and iridium(iii) complexes of the type [Cp*M(curc/bdcurc)Cl] and [Cp*M(curc/bdcurc)(PTA)][SO3CF3], in which Cp* = pentamethylcyclopentadienyl, curcH = curcumin and bdcurcH = bisdemethoxycurcumin as O^O-chelating ligands, and PTA = 1,3,5-triaza-7-phosphaadamantane, is described. The X-ray crystal structures of three of the complexes, i.e. [Cp*Rh(curc)(PTA)][SO3CF3] (5), [Cp*Rh(bdcurc)(PTA)][SO3CF3] (6) and [Cp*Ir(bdcurc)(PTA)][SO3CF3] (8), confirm the expected "piano-stool" geometry. With the exception of 5, the complexes are stable under pseudo-physiological conditions and are moderately cytotoxic to human ovarian carcinoma (A2780 and A2780cisR) cells and also to non-tumorigenic human embryonic kidney (HEK293) cells, but lack the cancer cell selectivity observed for related arene ruthenium(ii) complexes