A multivariate non-parametric approach for estimating probability of exceeding the local natural background level of arsenic in the aquifers of Calabria region (Southern Italy).

The concept of natural background level (NBL) aims at distinguishing the natural and anthropogenic contributions to concentrations of specific contaminants, as groundwater management and protection tools. This is usually defined as a unique value at a regional scale, even when the hydrogeological and geochemical features of a certain territory are far from homogeneous. The concentration of target contaminants is affected by multiple hydrogeochemical processes. This is the case of arsenic in the Calabria region, where concentrations are definitely variable in groundwater. To overcome the limitation of a traditional approach and to include the intrinsic hydrogeological and geochemical heterogeneity into the definition of the natural contribution to As content in groundwater, an integrated probabilistic approach to the NBL assessment combining aquifer-based preselection criteria and multivariate non-parametric geostatistics was proposed. In detail, different NBL values were selected, based on the aquifer type and/or hydrogeochemical features. Then, these aquifer-based NBL values of arsenic were used in the Probability Kriging method to map the probability of exceedance and to provide contamination risk management tools. This multivariate geostatistical approach that takes advantage of the physico-chemical variables used in the aquifer-based NBL values definition allowed mapping the probability of exceedance of As in a physically-based way. The hydrogeochemical diversity of the study area and all the processes affecting As concentrations in the aquifers have been considered too. As a result, the obtained map was characterized by a short-range and long-range variability due to local hydrogeochemical anomalies and water-rock interaction and/or atmospheric precipitation. By this approach, the NBL exceedance probability maps proved to be less "noisy", because the local hydrogeochemical conditions were filtered, and more capable of pointing out anthropogenic inputs or very anomalous natural contributions, which need to be investigated more in detail and properly managed.

Superparamagnetic iron oxides nanoparticles from municipal solid waste incinerators.

During their production, management, and landfilling, bottom (BA) and fly (FA) ashes from municipal solid waste incineration may liberate Fe-bearing, ultrafine particles and easily enter different environmental sinks of the biosphere. We aim to explore a collection of BA and FA samples from Italian incinerators to probe magnetic mineralogy and the fraction of harmful superparamagnetic (SP) nanoparticles (d<30nm). X-ray diffraction, electron microscopy observation, temperature- and frequency-dependent magnetometry, and Mossbauer analysis are performed. The integration of information from our rock magnetic and non-magnetic techniques leads us to conclude that the dominant magnetic carrier in our samples is magnetite and its intermediate/impure forms, while sulphides (i.e., monoclinic pyrrhotite) are important ancillary magnetic phases. The SP fraction fluxing from the BA and FA outputs of a single incinerator is detected and estimated in 103tons/year. This work stresses the need to calibrate the current technologies towards a safer management of combustion ashes and certainly to inform the environmental impact assessment by using a combination of different methods.

Metal removal from Municipal Solid Waste Incineration fly ash: A comparison between chemical leaching and bioleaching.

Bio- and hydrometallurgical experimental setups at 2-l reactor scale for the processing of fly ash from municipal waste incinerators were explored. We aimed to compare chemical H2SO4 leaching and bioleaching; the latter involved the use of H2SO4 and a mixed culture of acidophilic bacteria. The leaching yields of several elements, including some of those considered as critical (Mg, Co, Ce, Cr, Ga, Nb, Nd, Sb and Sm), are provided. At the end of the experiments, both leaching methods resulted in comparable yields for Mg and Zn (>90%), Al and Mn (>85%), Cr (∼65%), Ga (∼60%), and Ce (∼50%). Chemical leaching showed the best yields for Cu (95%), Fe (91%), and Ni (93%), whereas bioleaching was effective for Nd (76%), Pb (59%), and Co (55%). The two leaching methods generated solids of different quality with respect to the original material as we removed and significantly reduced the metals amounts, and enriched solutions where metals can be recovered for example as mixed salts for further treatment. Compared to chemical leaching the bioleaching halved the use of H2SO4, i.e., a part of agent costs, as a likely consequence of bio-produced acid and improved metal solubility.

Marine sediment contamination and dynamics at the mouth of a contaminated torrent: The case of the Gromolo Torrent (Sestri Levante, north-western Italy).

In this study we have examined the currents and hydrological characteristics of the water column off the mouth of the Gromolo Torrent (north-western Italy) in relation to the grain-size, mineralogical characteristics and metal distribution in the marine sediment sampled. Our purpose was to quantify and map the contamination that was carried out to sea from the abandoned Libiola Fe-Cu sulphide mine that has heavily impacted the torrent. Our results show high concentrations of Cu and Zn, and relatively high concentrations of Cd and Ni inside the bay into which the Gromolo Torrent flows. However, high concentrations of As, Cr, Hg, Mn, Pb, and V found in the northern and/or eastern parts of the study area originated from other sources. The subdivision of study stations in terms of metal and mineral contents in the bottom sediments highlighted the clear influence of the currents on their dispersion and distribution in the area.

Effect of temperature on the release and remobilization of ecotoxic elements in AMD colloidal precipitates: the example of the Libiola copper mine, Liguria, (Italy).

Due to their characteristics, colloidal particles are able to control the dispersion of many organic and inorganic pollutants in soils and streams. Colloidal precipitates generated by acid mine drainage (AMD) process are usually amorphous or nanocrystalline materials, and their stability plays a crucial role in controlling the fate of metals released by sulphide oxydation. This paper describes a study of elements release (Fe, Al, Mn, Cd, Co, Cr, Cu, Ni, S, Zn) due to desorption or destabilization of three different colloidal precipitates, two ochreous and a greenish-blue precipitate, sampled at the Libiola mine site (northwest Italy). The samples were heated at high temperature in order to verify this treatment as inertization process. At room temperature, the most easily extracted element was S (with released percentages from 8.39 to 29.17 %), but considerable amounts of Cu, Zn and Mn (up to 16.6, 610.6 and 595.6 mg/kg, respectively) were also observed in the leachates for greenish-blue precipitates. The highest release of elements (S > Cu, Zn, Mn, Cd > Co, Ni > Al, Fe, Cr), with minor differences depending on the mineralogical composition of the samples, was observed for heat-treated samples obtained through moderate heating and mainly formed by anhydrous phases. Samples treated at high temperature had the lowest release, with only Cu showing a significant concentration in the leachate of greenish-blue precipitates. The results showed that dissolution/desorption is limited from ochreous natural colloidal precipitates occurring at the Libiola mine site but also that high amounts of some metals can be remobilized from greenish-blue precipitates. The destabilization of all percipitates through dehydratation-dehydroxylation can further remobilize important amounts of ecotoxic elements. Heat treatment at high temperature could be a definitive, although expensive, way to fix heavy metals in the solid fraction, preventing their dispersion in the surrounding environment.

Selective zircon accumulation in a new benthic foraminifer, Psammophaga zirconia, sp. nov.

Benthic foraminifera are single-celled eukaryotes that make a protective organic, agglutinated or calcareous test. Some agglutinated, single-chambered taxa, including Psammophaga Arnold, 1982, retain mineral particles in their cytoplasm, but the selective mechanism of accumulation is not clear. Here, we report the ability of a foraminiferal species to select and accumulate zircons and other heavy minerals in their cytoplasm. In particular, the use of Scanning Electron Microscope coupled with an Energy Dispersive X-ray microanalysis system (SEM-EDS) enabled a representative overview of the mineral diversity and showed that the analysed Psammophaga zirconia sp. nov. individuals contained dominantly crystals of zircon (51%), titanium oxides (27%), and ilmenite (11%) along with minor magnetite and other minerals. The studied specimens occur in the shallow central Adriatic Sea where the sediment has a content of zircon below 1% and of other heavy minerals below 4%. For that reason we hypothesize that: (i) P. zirconia may be able to chemically select minerals, specifically zircon and rutile; (ii) the chemical mechanism allowing the selection is based on electrostatic interaction, and it could work also for agglutinated foraminifera (whether for ingestion, like Xenophyophores, or incorporation in the test as in many other described taxa). In particular, this aptitude for high preferential uptake and differential ingestion or retention of zircon is reported here for the first time, together with the selection of other heavy minerals already described in members of the genus Psammophaga. They are generally counted among early foraminifera, constructing a morphologically simple test with a single chamber. Our molecular phylogenetic study confirms that P. zirconia is a new species, genetically distinctive from other Psammophaga, and occurs in the Adriatic as well as in the Black Sea.

A registry for the collection of data in cochlear implant patients.

The need to optimize the use of all the information that modern technological tools have made available to the physician ENT/audiologist has increasingly emerged within the Italian scientific community. Towards this purpose, it is necessary to create a registry of the patients using cochlear implants (CIs). This registry will include a homogeneous summary of the information deriving from multiple sources related to daily clinical practice, in order to assess auditory benefits, safety and reliability in patients with cochlear implants, and organization over the national territory. The primary objectives relative to the above-mentioned analysis are to assess the impact of the use of cochlear implants on patient health, to ensure traceability of the devices currently used, monitoring their safety and reliability over time, to guarantee access of the technique in clinical and organizational conditions that can allow the best possible benefits. The aspects concerning implementation of the registry were discussed extensively during the first meetings of the Working Group (WG). In particular, owing to the complexity and high costs related mainly to the development of the technological aspects and the need to involve technological partners external to the WG, and to respect current privacy laws, the WG members decided that the project should be limited to proposal of a paper registry to be implemented at a later stage, possibly within the framework of successive research projects. During meetings, the WG members discussed various aspects of implementation of the registry, and in particular the scientific features connected to objectives, inclusion criteria, and structure of the forms needed for data collection and organizational aspects. A registry is proposed herein.

Transfer of selected mineral nutrients and trace elements in the host-hemiparasite association, Cistus-Odontites lutea, growing on and off metal-polluted sites.

The role of a hemiparasitic life-style in plant resistance to toxic trace elements in polluted soils is unclear. Restriction of metal uptake by the host, restriction of metal transfer from host to parasite, or transformation of metals into a less toxic form may play a role. This study analysed the transfer of selected mineral elements from soil to host (Cistus spp.) and from host to hemiparasite (Odontites lutea) at locations with different metal burdens: a Cu-rich serpentine site, Pb-Ba mine spoil and an unpolluted soil. Highest soil-to-host transfer factors for K, Mg, Ca, Zn, Cu and Pb were observed on the unpolluted soil. Statistically significant differences among locations of host-to-parasite transfer factors were only found for Ca and Pb. Restriction of transfer of unfavourable Ca/Mg ratios, characteristic at the serpentine site, and of high Pb and Zn concentrations at the Pb-Ba mine occurred mainly at the soil-host, and not at the host-parasite, level. Odontites lutea was able to withstand enhanced Zn and Pb concentrations and low Fe/Cu ratios in shoot tissue without developing toxicity symptoms. This could be caused by specific metal resistance mechanisms in this hemiparasite and/or the transformation and transfer of these metals into a less toxic form by the metal-tolerant host.