Benthic diatom community response to metal contamination from an abandoned Cu mine: Case study of the Gromolo Torrent (Italy).

Environmental contamination has become a global problem of increasing intensity due to the exponential growth of industrialization. One main debated issue is the metal contamination of rivers receiving Acid Mine Drainage (AMD) from active/abandoned mines. In order to assess the quality of lotic systems, diatoms are commonly used, as their assemblage modifies on the basis of changes in environmental parameters. Benthic diatom changes were analyzed along the metal-impacted Gromolo Torrent (Liguria, NW Italy) with the aim of understanding the effects of input from the abandoned Libiola Cu mine. The results support the hypothesis that metals from AMD lead to massive changes in diatoms, resulting in low biological diversity and in a shift of dominance, passing from the genera Cymbella and Cocconeis to more tolerant and opportunistic species, such as Achnanthidium minutissimum and Fragilaria rumpens. The high concentrations of labile metals, measured through Diffusion Gradients in Thin-films (DGT) immediately downstream of the two AMD inputs in the torrent, corresponded to a sudden decrease in the presence of diatoms, indicating the possible reaching of acute toxic levels. In particular, A. minutissimum dominated the mining area and was positively correlated with Cu and Zn; whereas F. rumpens bloomed downstream of this area, where the metal content was diluted, and was positively correlated with As and Pb. Finally, an important abundance of Nitzschia palea and teratological forms of A. minutissimum and F. rumpens were observed downstream from the mine, indicating that metals may have an important impact on diatoms up to the torrent mouth.

The EU Interreg Project "GEREMIA" on waste management for the improvement of port waters: results on monitoring the health status of fish as bioindicator.

Highly anthropized areas as ports represent complex scenarios that require accurate monitoring plans aimed to address the environmental status. In this context, the activities of the EU Interreg Project "GEstione dei REflui per il MIglioramento delle Acque portuali (GEREMIA)" were focused on comparing sites differently affected by human presence, as the Port of Genoa and the natural area of the S'Ena Arrubia fishpond: a panel of analyses was carried out on Mugilidae fish sampled in these two areas, aimed to address trace metal accumulation in the liver, gills, and muscle, as well as cytochrome P450 (CYP450) induction in liver and biliary polycyclic aromatic hydrocarbon (PAH) metabolites, and histopathological alterations in the liver and gills. Chemical analyses in the liver, gills, and muscle of specimens collected in the port area showed an overall higher degree of trace metal contamination compared to the natural fishpond, and similar results were obtained in terms of CYP450 induction and biliary PAH metabolites, suggesting a higher exposure to organic compounds. In addition, histopathological analyses revealed a significant alteration and then a loss of functionality of liver and gill tissue in individuals from the port. Overall, this study describes the complex environmental pollution scenario in the Port of Genoa, confirming the importance of using multidisciplinary approaches and different types of analyses to address both the presence and the effects of contaminants in marine environments.

Biofilm-induced effect on the buoyancy of plastic debris: An experimental study.

Plastic floating on the ocean surface represents about 1 % of all plastic in the ocean, despite the buoyancy of most plastics. Biofouling can help to sink debris, which could explain this discrepancy. A set of laboratory experiments was conducted to investigate biofilm-induced effects on the buoyancy of different plastic debris. Ten materials of different densities (buoyant/non-buoyant), sizes (micro/meso/macro), and shapes (irregular/spherical/cylindrical/flat), including facemasks and cotton swabs, were evaluated. Biofilm was incubated in these materials from a few weeks to three months to investigate the effect of different growth levels on their buoyancy. Biofilm levels and rising/settling velocities were measured and compared at seven time-points. The results show a hindered buoyancy for solid materials, while hollow and open materials showed the opposite trend in early biofilm colonization stages. A relationship was established between biofilm-growth and equivalent sphere diameter that can be used to improve predictive modeling of plastic-debris transport.

Mugilidae fish as bioindicator for monitoring plastic pollution: Comparison between a commercial port and a fishpond (north-western Mediterranean Sea).

In the last decade, interest in monitoring and managing plastic pollution has greatly increased. This study compared levels of microplastic contamination in stomachs of Mugilidae fish, suggesting this family as a target for plastic pollution monitoring in areas with different degrees of anthropisation. Two sites characterised by low and high anthropic impact, a fishpond (S'Ena Arrubia, Italy) and a port (Genoa, Italy), respectively, were compared. This study highlighted a stronger microplastic contamination in the port, with a higher percentage of fish showing the presence of microplastics and a larger polymeric variability compared to the fishpond. The microplastic number in fish from the port was higher than in the literature, but it was not significantly different from S'Ena Arrubia in terms of the microplastic percentage found in single individuals. Biomonitoring of microplastic contamination in Mugilidae fish resulted in a valid tool for the investigation of areas differently affected by human activity.

Microplastics in the abyss: a first investigation into sediments at 2443-m depth (Toulon, France).

Plastic and microplastic pollutions are known to be widespread across the planet in all types of environments. However, relatively little about microplastic quantities in the deeper areas of the oceans is known, due to the difficulty to reach these environments. In this work, we present an investigation of microplastic (<5 mm) distribution performed in the bottom sediments of the abyssal plain off the coast and the canyon of Toulon (France). Four samples of deep-sea sediment were collected at the depth of 2443 m during the sea operations carried out by the French oceanographic cruises for the KM3NeT project. The chemical and physical characterisation of the sediment was carried out, and items were extracted from sediments by density separation and analysed by optical microscope and µRaman spectroscopy. Results show microplastics in the deep-sea sediments with a concentration of about 80 particles L-1, confirming the hypothesis of microplastics spread to abyssal sediments in the Mediterranean Sea.

Microplastics in seawater and marine organisms: Site-specific variations over two-year study in Giglio Island (North Tyrrhenian Sea).

Geographical and temporal differences of microplastic occurrence were documented in water and fish collected in 2017 and 2019 from the Giglio Island (North Tyrrhenian Sea) close to the area where the Costa Concordia sank in January 2012. Results on water samples showed a site-dependent difference, suggesting the role of surface current dynamics in the microplastic local distribution, while tested Neuston nets (200 µm and 330 µm mesh size) did not influence microplastic retention efficiency. Fish exhibited in 2019 a higher frequency of specimens positive to microplastic ingestion with respect to 2017, with an occurrence higher than those typically observed in other Mediterranean areas. Both in water and fish, fragments were the dominating shape, polypropylene and polyethylene were the prevalent polymers, without particular difference between sites and years. This study highlights the importance of applying microplastic investigation in biotic and abiotic matrices for an effective monitoring of this pollution in the marine environment.

The Need for Collective Awareness of Attempted Suicide Rates in a Warming Climate.

Background: Climate factors may offer a stronger explanation of the variations in suicide rates compared with economic variables, even in the case of patients admitted involuntarily. Aims: We assessed the role of temperature as a determinant of the increased prevalence of suicide attempts (SA). Method: The sample comprised all cases of hospitalization for SA at the Psychiatric Clinic of the IRCCS Ospedale Policlinico San Martino between August 2013 and July 2018. For ambient temperature, data were provided by the Meteorological Observatory of the University of Genoa. Results: We noted a peak in suicides that was typically found in late spring and early summer due to global warming. Limitations: Other environmental/psychological factors contributing to the onset of an acute clinical event were not considered. The cross-sectional design of the study is another limitation. Conclusion: Further studies are needed to clarify the impact of climatic factors on suicide behavior and implement early intervention and preventive strategies for mental health.

Considerations on salts used for density separation in the extraction of microplastics from sediments.

Environmental contamination by plastics and microplastics is a recognised problem worldwide, and it is the focus of many research teams. In the quantification of microplastics in the environment (plastic items with dimensions between 1 µm and 5 mm), the search for shared and universally recognised protocols and methodologies is still ongoing. In this study, the use of a method for extracting microplastics from marine sediments based on density separation has been considered. Fifty studies were analysed to investigate the scenario of salts exploited during microplastic extraction. The most commonly used salts are NaCl (45.6%), ZnCl2 (19.3%) and NaI (17.5%). Considerations related to cost, availability, hazards of the salts and thus the repeatability of the related extraction method are reported. In light of the findings, NaCl remains the most readily usable, economical and effective salt for the extraction of microplastics from marine sediments.

Port Sediments: Problem or Resource? A Review Concerning the Treatment and Decontamination of Port Sediments by Fungi and Bacteria.

Contamination of marine sediments by organic and/or inorganic compounds represents one of the most critical problems in marine environments. This issue affects not only biodiversity but also ecosystems, with negative impacts on sea water quality. The scientific community and the European Commission have recently discussed marine environment and ecosystem protection and restoration by sustainable green technologies among the main objectives of their scientific programmes. One of the primary goals of sustainable restoration and remediation of contaminated marine sediments is research regarding new biotechnologies employable in the decontamination of marine sediments, to consider sediments as a resource in many fields such as industry. In this context, microorganisms-in particular, fungi and bacteria-play a central and crucial role as the best tools of sustainable and green remediation processes. This review, carried out in the framework of the Interreg IT-FR Maritime GEREMIA Project, collects and shows the bioremediation and mycoremediation studies carried out on marine sediments contaminated with ecotoxic metals and organic pollutants. This work evidences the potentialities and limiting factors of these biotechnologies and outlines the possible future scenarios of the bioremediation of marine sediments, and also highlights the opportunities of an integrated approach that involves fungi and bacteria together.

Meteorological Variables and Suicidal Behavior: Air Pollution and Apparent Temperature Are Associated With High-Lethality Suicide Attempts and Male Gender.

This study analyzed the impact of meteorological variables and high-lethality suicide attempts (HLSA) to assess a potential time shift of HLSA affected by climate evolution to predict the suicide attempt cases over different periods of the year. After attempting suicide, 225 subjects were admitted to the emergency ward of the IRCCS Ospedale Policlinico San Martino and later to the psychiatric unit from March 2016 to July 2018. Socio-demographic and clinical characteristics as well as the meteorological variables were collected. The Mann-Kendall test as well as redundancy and cross-correlation analyses were performed to analyze the trends, statistically correlations, and correspondence of the trends, respectively between suicidal behaviors and climatic factors. Sixty-seven (29.8%) committed a HLSA. Our findings indicate a significant association between HLSA and male gender and apparent temperature with a strong correlation of 75% with a phase shift of -1 month. Solar radiation and air pollution (PM2.5) have a positive correlation of 65 and 32%, respectively, with a zero-time lag. Limitations include that the data are limited to a single hospital; psychological factors, or other clinical variables that could be ruled out as a trigger have not been considered. Meteorological variables may not mirror the temperature that the patient is exposed to due to the air conditioning systems. Exploring those environmental factors associated with HLSA in a more detailed manner could lead to early intervention and prevention strategies for such distressing admissions.

Sediment distribution on the continental shelf in relation to stream inputs and contamination: hydrodynamic, chemical, mineralogical, and sedimentological characteristics (Ligurian Sea, Italy).

River estuaries, continental shelf, and sediment contamination are closely linked from the point of view of sediment transport and diffusion that is governed by different factors such as sea waves and currents, river flows and floods, and sediment characteristics. Taking these factors into consideration, we have examined marine environmental and marine bottom sediments off the mouth of a stream to highlight the main ways of sediment and contaminant transport and diffusion on the continental shelf. For this purpose, we followed a multidisciplinary approach, studying circulation of water masses, hydrological characteristics of water column, distribution and main characteristics of sediment grain size, sediment mineralogical composition, and metal concentrations of bottom sediments. Our results allowed identifying the presence of preferential ways of sediment deposition and areas of sediment spread for the Entella Stream, as well as the origin of some metals.

Baseline of distribution and origin of Rare Earth Elements in marine sediment of the coastal area of the Eastern Gulf of Tigullio (Ligurian Sea, North-West Italy).

A study on the Rare Earth Element (REE) distribution in the bottom sediments of the Gulf of Tigullio (north-west Italy) was conducted. The results constitute a baseline for this zone of the Ligurian Sea and enabled the obtaining of valuable information on the origin and transport of sediments in the gulf. The distribution of REEs is controlled by phosphates, mainly monazite, and is generally homogeneous in the study area, reflecting the homogeneous distribution of the minerals. Some differences in REE and Sc distribution allow us to identify two sub-basins (Entella and Gromolo torrent sub-basins) characterised by slightly different geological frameworks. The "hat-shaped" observed patterns seem to indicate an overprinting of the original REE patterns due to exchanges between phosphates and seawater. REEs seem to be related with the rocks outcropping in the area, although an indirect effect of anthropic activity could be seen near a fish farm.

Microplastics in seawater: sampling strategies, laboratory methodologies, and identification techniques applied to port environment.

The European Interreg Italy-France 2014-2020 Maritime Project SPlasH! (Stop to Plastics in H2O!) focused on the study of microplastics (MPs) in the marine port environment to evaluate their presence, abundance, and mechanisms of diffusion to the open sea. In the framework of this project, a worldwide review of 74 studies was carried out, providing an overview of MP investigation techniques, focusing on sampling strategies, laboratory methodologies, and identification of MPs collected in seawater, and specifically evaluating their applicability to the marine port environment. Nets were the most commonly used device for MP surface sampling, but their use can be difficult in narrow spaces within the port basins, and they must be coupled to discrete sampling devices to cover all port basins. In the laboratory, density separation (NaCl, ZnCl2, NaI, sodium lauryl sulfate (SLS)), filtration (polycarbonate, polyamide, glass, cellulose, ANOPORE inorganic membrane filters), sieving, visual sorting, and digestion methods (acidic, enzymatic, alkaline, oxidative) were used to separate MPs from seawater. Digestion becomes essential with water samples with great inorganic and organic loads as deriving from a port. Although many studies are based only on visual MP identification under a microscope, analytical identification techniques unequivocally determine the particle nature and the identity of the plastic polymers and are necessary to validate the visual sorting of MPs. Fourier-transform infrared spectroscopy (FTIR) is the most used analytical identification technique.

Correction to: Microplastics in seawater: sampling strategies, laboratory methodologies, and identification techniques applied to port environment.

The article Microplastics in seawater: sampling strategies, laboratory methodologies, and identification techniques applied to port environment.

Environmental implications of metal mobility in marine sediments receiving input from a torrent affected by mine discharge.

Acid Mine Drainage (AMD) is one of the most important sources of pollution in fluvial systems and can enrich rivers in dissolved and suspended metals of environmental concern. Colloidal particles may favour the transport of metals to the sea, where metals can be accumulated in bottom sediments. The aim of this paper was to evaluate the mobility of metals in the "Baia delle Favole" bottom sediments (Sestri Levante, Italy), which receive the input of the AMD impacted Gromolo Torrent, using chemical speciation (BCR sequential extraction). Basing on the Risk Assessment Code (RAC), our results showed a systematic and widespread high risk classification for Mn, whereas a medium risk is associated to Co, Cu, and Zn in the sediments collected near the mouth of the Gromolo Torrent. Moreover, in these sediments the occurrence of Fe oxyhydroxides has been observed, reflecting an increase of metals in the reducible fraction obtained with BCR.

Baseline evaluation of metal contamination in teleost fishes of the Gulf of Tigullio (north-western Italy): Histopathology and chemical analysis.

Metals, whether essential (Cu, Zn, Cr, Fe, Mn) or non-essential (Al, As, Cd, Ni, Pb, Hg) for organism metabolism, occur naturally in the marine environment and their abundance can increase due to the presence of human activities. In this study, fish were used as bio-indicators, to determine a correlation between the bio-accumulation of metals in muscle and gill tissues and the health status of fish. The study area was the Gulf of Tigullio (north-western Italy), which is impacted by various sources of metal contamination. Histopathology served as a significant tool to investigate possible alterations in gills, one of the main organs involved in fish physiology. Results highlighted some correlations between certain metals (e.g. Pb, Ni) and gill alterations (e.g. epithelial hyperplasia, epithelial lifting), providing baseline data from a pool of different fish species, which can be used for comparison purposes in further studies.

Fungi as potential tool for polluted port sediment remediation.

Contaminated sediments represent an important management problem that also concerns their remediation. Indeed, port dredging activities produce huge volumes of contaminated sediments that, in turn, require proper handling because of their quantity of inorganic and organic substances. Conventional management-remediation strategies of polluted sediment involve sediment washing, electron-chemical separation, and thermal treatment. Recently, bioremediation strategies have also been proposed as a promising answer to the problem of contaminated sediments. In this context, fungi are pioneer microorganisms known to bioconcentrate, bioaccumulate, and biostabilize heavy metals. These capabilities suggest the potential to employ indigenous fungal strains to remediate polluted port sediments. In the framework of the European Project SEDITERRA (Guidelines for the sustainable treatment of dredged sediments in the Marittimo area), the aim of this paper is to characterize the fungal communities of port sediments of Genoa and present an innovative mycoremediation protocol to evaluate the capability of indigenous fungal strains in the heavy metal remediation. In this study, Penicillium expansum Link and Paecilomyces formosus (Sakag., May. Inoue & Tada) Houbraken & Samson have been selected as fungal species for the mycoremediation treatments. The protocol requires a fungal membrane system and the results highlight efficient bioremoval of Cu and Zn from sediments.

The effects of dredging and environmental conditions on concentrations of polycyclic aromatic hydrocarbons in the water column.

Sediment dredging can cause damage to the marine environment due to mobilization of sediments and contaminants. The effects of dredging and boundary environmental conditions on the concentration of Polycyclic Aromatic Hydrocarbons (PAHs) in water were evaluated during dredging of the Oil Port of Genoa-Multedo (Italy). Results showed that turbidity and PAH concentrations increased in the water during dredging. However, the scenario was complex due to the high number of interacting physical-chemical factors influencing PAH concentrations and transport. Due to these, PAH distribution is different in water, where low-molecular-weight PAHs were predominant (maximum concentration 0.105 µg L-1), and in bottom sediments, where high-molecular-weight PAHs had the highest concentrations (from 299.3 to 1256.5 ng g-1). Moreover, mainly during dredging the PAH concentrations in water were significantly higher inside than outside the port as a consequence of the lower dynamics within the port basin. Turbidity was the main parameter related to PAH concentrations.

Metal transport and remobilisation in a basin affected by acid mine drainage: the role of ochreous amorphous precipitates.

Metal-polluted mine waters represent a major threat to the quality of waters and sediments in a downstream basin. At the confluence between acidic mine waters and the unpolluted waters of the Gromolo Torrent (Liguria, North-West Italy), the massive formation of an ochreous amorphous precipitate takes place. This precipitate forms a soft blanket that covers the torrent bed and can be observed down to its mouth in the sea. The aim of this work is to evaluate the dispersion of metals in the Gromolo Torrent basin from the abandoned Cu-Fe sulphide mine of Libiola to the Ligurian Sea and to assess the metal remobilisation from the amorphous precipitates. The mineralogy of the superficial sediments collected in the torrent bed and the concentrations of different elements of environmental concern (Cu, Zn, Cd, Co, Cr, Mn, Ni, Pb, As, and Sb) were therefore analysed. The results showed that the precipitates contain high concentration of Fe, Al, Cu, and Zn, significantly modifying the bulk chemistry of the Gromolo Torrent sediments. In order to evaluate the possible remobilisation of ecotoxic elements from the amorphous precipitates, bulk leaching tests were performed with both deionised and seawater. Bulk leaching tests with deionised water mobilised primarily high Pb amounts, but also relatively high concentrations of Fe, Al, Cu, and Zn are released in the leachate. In seawater tests, Fe, Al, Cu, and Zn were released in smaller amounts, while other elements like Mn, Cd, Co, and Ni increased in the released fraction. Pb was still strongly released as in deionised water experiments. The results show that the interaction of precipitates and seawater can remobilise high concentrations of metals, thus affecting the surrounding environment.