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Metallic structures in service in seawater are protected by coupling cathodic protection and paints, where the former may induce disbondment of the latter. A preliminary evaluation of the cathodic disbondment risk can be made by cathodic disbondment tests (CDTs). Many CDTs use cathodic potentials as large as E < −1400 mV versus saturated calomel electrode (SCE) applied up to 90 days. Only two CDT protocols require contemporary anode isolation, current and pH monitoring, without its correction. These three aspects were considered to develop a hybrid CDT; it consisted of polarizing steel panels at −1500 mV versus SCE for 12 weeks. The chemical effects related to the anodic processes were investigated. A pH acidic shift was observed and was justified by the increasing current demand due to paint damage and brucite precipitation on the panels. The necessity of anode isolating glass to prevent chlorine chemical attack against the paints, potentially affecting the disbondment result, was verified by estimating the virtual chemical attack induced by free chlorine. In conclusion, current monitoring, pH control and anode isolation are highly suggested to correctly conduct and interpret the cathodic disbondment results when CDTs requiring large electronegative potentials are applied for long periods. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the ecotoxicity of polyvinylidene difluoride (PVDF) and polylactic acid (PLA) microplastics (MPs) in two marine zooplankton: the crustacean Artemia franciscana and the cnidarian Aurelia sp. (common jellyfish). To achieve this goal, (i) MP uptake, (ii) immobility, and (iii) behavior (swimming speed, pulsation mode) of crustacean larval stages and jellyfish ephyrae exposed to MPs concentrations (1, 10, 100 mg/L) were assessed for 24 h. Using traditional and novel techniques, i.e., epifluorescence microscopy and 3D holotomography (HT), PVDF and PLA MPs were found in the digestive systems of the crustaceans and in the gelatinous tissue of jellyfish. Immobility was not affected in either organism, while a significant behavioral alteration in terms of pulsation mode was found in jellyfish after exposure to both PVDF and PLA MPs. Moreover, PLA MPs exposure in jellyfish induced a toxic effect (EC50: 77.43 mg/L) on the behavioral response. This study provides new insights into PLA and PVDF toxicity with the potential for a large impact on the marine ecosystem, since jellyfish play a key role in the marine food chain. However, further investigations incorporating additional species belonging to other trophic levels are paramount to better understand and clarify the impact of such polymers at micro scale in the marine environment. These findings suggest that although PVDF and PLA have been recently proposed as innovative and, in the case of PLA, biodegradable polymers, their effects on marine biota should not be underestimated. [ABSTRACT FROM AUTHOR]

The aim of this research was to determine the resistance of acetylated wood against marine biodeterioration in use class 5 for use in temperate waters. The resistance of acetylated radiata pine (Pinus radiata D. Don) on solid and medium-density fiberboard (MDF) panels was compared with untreated wood of European species, such as European beech (Fagus sylvatica L.), sweet chestnut (Castanea sativa Mill.), European oak (Quercus robur L.), and marine plywood. As a reference control, untreated Scots pine (Pinus sylvestris L.) sapwood was used. The field tests were carried out in accordance with EN 275, and started in April 2015. The three Italian exposure sites were Marine of Scarlino private harbor, Port of Genoa, and the Venice Lagoon. Final evaluation in 2021 showed a greater resistance to marine borers of acetylated wood, radiata pine, and beech and MDF panels. However, the untreated European species showed low resistance against marine organisms, with complete decay after the first year of exposure. [ABSTRACT FROM AUTHOR]

In this study, the acute toxicity of microplastics (MPs) on unicellular organisms as marine decomposers and microalgae was assessed, by evaluating standards endpoints included in International Standard Organization (ISO) protocols. The bacteria Vibrio fischeri and the diatom Phaeodactylum tricornutum were exposed to different sizes (1–500 μm) of polyethylene MPs in order to evaluate bioluminescence inhibition and microalgal growth. No acute toxicity was found on bacteria or microalgae in an order of magnitude above environmentally relevant concentrations, suggesting that tested MPs did not affect the investigated biological processes. In conclusion, standard ecotoxicological endpoints are not sufficiently sensitive to assess the potential effects of MPs on decomposers and primary producers, conversely to nanoplastics. These findings highlight that the current approach for MP risk assessment in unicellular species should be revised, by providing alternative endpoints to be included in standardized protocols, able to monitor the fate and biological effects of MPs. Unlabelled Image • Acute toxicity of polyethylene MPs on marine bacteria and microalgae was assessed. • Different sizes (1–500 μm) of MPs at low and high concentrations were tested. • MPs did not affect bacteria and algal growth inhibition. • Standard endpoints are not sufficiently sensitive to assess MP toxicity. • Alternative endpoints should be investigated and included in standardized protocols. [ABSTRACT FROM AUTHOR]

Abstract The Arctic is a unique and fragile ecosystem that needs to be preserved and protected. Despite its remoteness, plastic pollution has been documented in this region. In the coming years, it is likely to worsen since, with climate changes and the opening of new shipping routes, the human presence is going to increase in the whole area. Here, we investigated the presence of microplastics (MPs) in sub-surface water and in two mid-trophic level Arctic fishes collected off Northeast Greenland: the demersal bigeye sculpin, Triglops nybelini , and the pelagic polar cod, Boreogadus saida. Plastics debris were found in the water samples at a concentration of 2.4 items/m3 ±0.8 SD which is higher than in most seas at lower latitudes. Both fish species had eaten MPs with different proportion among the species, 34% for T. nybelini (n = 71) and 18% for B. saida (n = 85). The significant difference in the occurrence of MPs between the two species is likely a consequence of their feeding behavior and habitat. Polyethylene was the main plastic polymer for water samples (41%, n = 17) and polyester (34%, n = 156) for fish samples as analyzed by Fourier Transformed Infrared (FT-IR) spectroscopy. Our data underscore that the Arctic regions are turning into a hotspot for plastic pollution, and this calls urgently for precautionary measures. Graphical abstract Image 1 Highlights • Plastic debris was found at each sampling stations with an average abundance of 2.4 items/m3 (±0.8 SD). • 25% of investigated fish ingested plastics. • Need of unique and standardized MP protocols for reliable reporting. [ABSTRACT FROM AUTHOR]

The presence of toxicant needs to be assessed within short time in order to effectively protect the aquatic environment from serious threat. Based on the observation that at high temperatures aquatic organisms become more vulnerable to stressors than those maintained at room temperature, a new test was developed. The proposed bioassay consisted in the evaluation of the swimming speed alteration (SSA) of nauplii of Artemia franciscana incubated at 39 °C (± 1) for 6 h, using a Swimming Behavior Recorder system (SBR). A comparative ecotoxicological study between the 6 h SSA test and the 24 h mortality test was carried out in order to validate the new method in terms of sensitivity by means of EC 50 values. The bioassay was applied to screen different toxicants: K 2 Cr 2 O 7 , Cu(SO 4 ) 2 , NaClO, SDS and Sertraline hydrochloride. The EC 50s calculated for the short-term SSA test and those of the mortality test showed comparable values. For all toxicants, the 6 h SSA test was proved to be as sensitive as the 24 h mortality test. The method developed in this study is the first temperature-based toxicity test with nauplii of Artemia franciscana and it represents an attractive assay in ecotoxicology because of its convenience in terms of time and costs, feasibility and sensitivity. [ABSTRACT FROM AUTHOR]

Plastic debris accumulates in the marine environment, fragmenting into microplastics (MP), causing concern about their potential toxic effects when ingested by marine organisms. The aim of this study was to verify whether 0.1 µm polystyrene beads are likely to trigger lethal and sub-lethal responses in marine planktonic crustaceans. MP build-up, mortality, swimming speed alteration and enzyme activity (cholinesterases, catalase) were investigated in the larval stages of Amphibalanus amphitrite barnacle and of Artemia franciscana brine shrimp exposed to a wide range of MP concentrations (from 0.001 to 10 mg L -1 ) for 24 and 48 h. The results show that MP were accumulated in crustaceans, without affecting mortality. Swimming activity was significantly altered in crustaceans exposed to high MP concentrations (> 1 mg L -1 ) after 48 h. Enzyme activities were significantly affected in all organisms exposed to all the above MP concentrations, indicating that neurotoxic effects and oxidative stress were induced after MP treatment. These findings provide new insight into sub-lethal MP effects on marine crustaceans. [ABSTRACT FROM AUTHOR]

We investigated the biophysical properties of the transport mediated by ion channels in hemocytes from the hemolymph of the bivalve Mytilus galloprovincialis. Besides other transporters, mytilus hemocytes possess a specialized channel sensitive to the osmotic pressure with functional properties similar to those of other transport proteins present in vertebrates. As chloride fluxes may play an important role in the regulation of cell volume in case of modifications of the ionic composition of the external medium, we focused our attention on an inwardly-rectifying voltage-dependent, chloride-selective channel activated by negative membrane potentials and potentiated by the low osmolality of the external solution. The chloride channel was slightly inhibited by micromolar concentrations of zinc chloride in the bath solution, while the antifouling agent zinc pyrithione did not affect the channel conductance at all. This is the first direct electrophysiological characterization of a functional ion channel in ancestral immunocytes of mytilus, which may bring a contribution to the understanding of the response of bivalves to salt and contaminant stresses. [ABSTRACT FROM AUTHOR]

ABSTRACT We describe the use of different life stages of the Mediterranean sea urchin Paracentrotus lividus for the assessment of the possible risk posed by nanoparticles (NPs) in the coastal water. A first screening for the presence of NPs in sea water may be obtained by checking their presence inside tissues of organisms taken from the wild. The ability of NPs to pass from gut to the coelomic fluid is demonstrated by accumulation in sea urchin coelomocytes; the toxicity on sperms can be measured by embryotoxicity markers after sperm exposure, whereas the transfer through the food chain can be observed by developmental anomalies in larvae fed with microalgae exposed to NPs. The most used spermiotoxicity and embryotoxicity tests are described, as well as the biochemical and histochemical analyses of cholinesterase (ChE) activities, which are used to verify toxicity parameters such as inflammation, neurotoxicity, and interference in cell-to-cell communication. Morphological markers of toxicity, in particular skeletal anomalies, are described and classified. In addition, NPs may impair viability of the immune cells of adult specimens. Molecular similarity between echinoderm and human immune cells is shown and discussed. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1552-1562, 2016. [ABSTRACT FROM AUTHOR]

The Mar Piccolo of Taranto (Ionian Sea, Southern Italy) is a semi-enclosed and strongly polluted basin. For decades, it has been subjected to different anthropogenic impacts. These stressors caused severe sediments contamination with high concentration of different pollutants (PAHs, PCB, heavy metals). In order to assess the current status of sediments contamination, an ecotoxicological investigation combined with chemical analysis (heavy metals, PAH, and PCB) has been performed. In order to derive ecologically relevant conclusions, a multiorganisms and multiend-points approach has been applied, exposing organisms from different trophic levels to elutriate and whole sediment. The battery of bioassays consists of a microalgal growth inhibition test ( Dunaliella tertiolecta), acute and sublethal assays (end-points: mortality, immobilization and swimming speed alteration) on crustaceans larvae and juveniles, and rotifers ( Amphibalanus amphitrite, Artemia salina, Corophium insidiosum and Brachionus plicatilis), and embryotoxicity test on echinoderms ( Paracentrotus lividus). Considering the high levels of sediment contamination highlighted from chemical analysis, an unexpected very low toxic effect was observed, even considering the sublethal end-point (larval swimming speed alteration). The results of this study suggest a very complex contaminants dynamic in the Mar Piccolo sediments that, despite a strong level of contamination, seems to not affect in a proportional manner the biological compartment. [ABSTRACT FROM AUTHOR]