The increased frequency and intensity of short-term extreme warming phenomena have been associated to harsh biological and ecosystem outcomes (i.e., mass mortalities in marine organisms). Marine heatwaves (MHWs), occurring when seasonal temperature threshold is exceeded for at least 5 consecutive days, may reduce the tolerance of coastal species toward additional pressures, but interactions between such multiple stressors are virtually unexplored. The present study aimed to characterize in Mytilus galloprovincialis the influence of a simulated MHW scenario on the toxicological effects of the pharmaceutical carbamazepine (CBZ), ubiquitously detected in the marine environment and chosen as model compound for this relevant class of emerging contaminants. The bioaccumulation of CBZ and responsiveness of various biological parameters, including immune system, antioxidant status, lipid metabolism and cellular integrity, were analyzed in exposed mussels both during and after the end of the heatwave. MHW appeared to strongly modulate accumulation of CBZ, paralleled by weakened immunocompetence and onset of oxidative disturbance that finally evolved to cellular damages and lipid metabolism disorders. Elaboration of the overall results through a quantitative Weight of Evidence model, revealed the highest hazard in organisms exposed to both the stressors 10 days after the end of the heatwave, suggesting that MHWs could leave a footprint on the capability of mussels to counteract CBZ toxicity, thus affecting their vulnerability and predisposition to adverse effects toward multiple stressors.

Amyl salicylate (AS) is a fragrance massively used as a personal care product and following the discharged in wastewaters may end up in the aquatic environment representing a potential threat for the ecosystem and living organisms. AS was recently detected in water of the Venice Lagoon, a vulnerable area continuously subjected to the income of anthropogenic chemicals. The lagoon is a relevant area for mollusc farming, including the Mediterranean mussels (Mytilus galloprovincialis) having an important economic and ecological role. Despite high levels of AS occurred in water of the Lagoon of Venice, no studies investigated the possible consequences of AS exposures on species inhabiting this ecosystem to date. For the first time, we applied a multidisciplinary approach to investigate the potential effects of the fragrance AS on Mediterranean mussels. To reach such a goal, bioaccumulation, cellular, biochemical, and molecular analyses (RNA-seq and microbiota characterization) were measured in mussels treated for 7 and 14 days with different AS Venice lagoon environmental levels (0.1 and 0.5 μg L⁻¹). Despite chemical investigations suggested low AS bioaccumulation capability, cellular and molecular analyses highlighted the disruption of several key cellular processes after the prolonged exposures to the high AS concentration. Among them, potential immunotoxicity and changes in transcriptional regulation of pathways involved in energy metabolism, stress response, apoptosis and cell death regulations have been observed. Conversely, exposure to the low AS concentration demonstrated weak transcriptional changes and transient increased representation of opportunistic pathogens, as Arcobacter genus and Vibrio aestuarianus. Summarizing, this study provides the first overview on the effects of AS on one of the most widely farmed mollusk species.

The increasing use of rare earth elements (REEs) in electric and electronic equipment has been associated with the presence of these elements in aquatic systems. The present study aimed to evaluate the toxicity of two REEs, Lanthanum (La) and Gadolinium (Gd), towards the mussel species Mytilus galloprovincialis. For this, the toxicity was assessed after a short-term exposure (14 days) to an environmentally relevant concentration of each element (10 μg/L), followed by a recovery period (14 days) in the absence of any contaminant. The measured biomarkers included energy-related parameters, activity of antioxidant and biotransformation enzymes, indicators of oxidative damage, levels of oxidized glutathione and neurotoxicity. After exposure mussels accumulated more La (0.54 μg/g) than Gd (0.15 μg/g). After recovery higher concentration decrease was observed for Gd (≈40% loss) compared to La exposed mussels (≈30% loss) which may be associated with lower detoxification capacity of mussels previously exposed to La. Mussels increased their metabolism (i.e., higher electron transport system activity) only after the exposure to Gd. Exposure to La and Gd resulted into lower energy expenditure, while when both elements were removed glycogen and protein concentrations decreased to values observed in non-contaminated mussels. Antioxidant and biotransformation capacity was mainly increased in the presence of Gd. This defense response avoided the occurrence of cellular damage but still loss of redox balance was found regardless the contaminant, which was re-established after the recovery period. Neurotoxicity was only observed in the presence of Gd with no effects after the recovery period. Results showed that a short-term exposure to La and especially to Gd can exert deleterious effects that may compromise specific biochemical pathways in aquatic species, such as M. galloprovincialis, but under low concentrations organisms can be able to re-establish their biochemical status to control levels after a recovery period.

The purposes of this study were to measure the concentrations of arsenic speciation in shellfish from South China Sea and evaluate the health risk by local residents through shellfish consumption. The median concentrations (in wet weight) of arsenic speciation in shellfish samples were in the following order: AsB (16.0 mg·kg⁻¹) > DMA (1.30 mg·kg⁻¹) > AsV (0.23 mg·kg⁻¹) > AsC (0.08 mg·kg⁻¹) > AsIII (0.05 mg·kg⁻¹) > MMA (0.01 mg·kg⁻¹). Among shellfish species, Mactra mera and Babylonia areolata were found to accumulate iAs and AsB, respectively. The target hazard quotient values of iAs (THQᵢAₛ) in all shellfish samples were lower than 1. However, the carcinogenic risk values of iAs (CRᵢAₛ) in the Mactra mera, Mytilus galloprovincialis and Pinctada margaritifera were beyond the acceptable range, implying that continuous exposure to iAs pollution via the consumption of these shellfish would pose a potential cancer risk to local consumers.

A number of trace elements (Mn, Fe, Co, Ni, Cu, Zn, As, Nb, Mo, Ag, Cd, Pb, U and the rare earth elements – REE) were analyzed in the dissolved phase, suspended particulate matter and in different organs (gills, hepatopancreas, and the rest of soft tissue) in mussels of the native Mytilus galloprovincialis and invasive Xenostrobus securis species in the Vigo Ria (NW Iberian Peninsula) in order to assess potential differences in their bioaccumulation patterns. Results obtained do not show significant differences in the bioaccumulation of trace elements by M. galloprovincialis and X. securis, except for Zn and Ag. In the case of Zn, a 4-fold enrichment in M. galloprovincialis compared to X. securis was found. The most important differences between species were observed for Ag, with approximately 40-fold higher concentrations in X. securis. Such elevated Ag bioaccumulation by X. securis can be useful for Ag biomonitoring using these invasive species in this area.

Increased Rare earth elements (REE) usage culminates in discharges into the environment. Mussels have been chosen as models in biomonitoring, hence, REE concentrations in Mytilus galloprovincialis from six locations on the Portuguese coast were accessed to determine natural concentrations and possible linkage to local ecosystem characteristics and temporal variations, by determining them in distinct seasons (autumn and spring). Samples from Porto Brandão (located on the south bank of the Tagus estuary) exhibited the highest REE concentrations, while mussels from Aljezur (the southernmost point on the Portuguese coast) exhibited the lowest, in both seasons. Overall, ∑REE concentration was greater in the spring. LREE enrichment relative to HREE occurs and a negative Ce and Eu anomaly was observed. This study constitutes the first assessment of REE composition on this model species in the Portuguese coast, in two distinct seasons and contributes to a better understanding of REE uptake for future biomonitoring studies.

Mussels, whose soft tissues are used in food and are rich in high-quality protein, are essential in marine fisheries. Mediterranean mussels (Mytilus galloprovincialis Lam) used to assesses the pollution level of a coastal marine zone due to exposure to local technological processes populate the metal piles of a pier built for the 2014 Olympics in Sochi Olympic Park. The chemical composition of mussel soft tissues (61 elements analyzed by the ICP method) indicates anthropogenic pollution of the coastal zone ecosystem, most pronounced in the 50-m zone along the coast due to run off from the terrestrial ecosystem affected by the Olympic construction. Line measurements of annual rings of 6-year-old individuals of mussels showed stabilization of the ecological situation in the coastal-marine zone by 2019. This study can be used for comprehensive ecological monitoring of coastal-marine zones with similar conditions and anthropogenic load.

Coastal harbor areas are subjected to a myriad of contamination sources with largely unknown effects. Such complex chemical mixtures are difficult to monitor but transcriptomics is a promising approach for such biomonitoring. The present study was designed to verify the use of the Coastal Biosensor for Endocrine Disruption (C-BED) assay, previously developed to detect emerging contaminants and their effects on Mytilus edulis, on another mussel species, Mytilus galloprovincialis. Mussels were caged on St-Florent harbor (contaminated) and on Revellata Bay (reference) for three months. A classical multibiomarkers approach was coupled to the C-BED assay. The results of both approaches were analysed using the Integrated Biomarkers Responses (IBR) and compared to each other. Both approaches demonstrated a higher contamination and probable endocrine disruption of mussels in St-Florent, compared to the reference station. These results confirm that the C-BED assay provides an innovative method to expand our ability to detect emerging contaminants.

The mussel M. galloprovincialis is one of the most popular species in world’s mariculture and environment pollution bioindicators. Although this mollusk was in a focus of numerous publications, the detoxifying and accumulating role of some of its body parts was insufficiently studied. The goals of the present work were as follows: (a) to study the distribution of potentially toxic elements (Cr, Co, Ni, Cu, Zn, As, Cd, Hg, Pb) in soft tissues, byssus, and shell liquor of this bivalve as a function of sampling location in the Black Sea near the southwestern coast of Crimea and (b) to assess human health risks from consuming soft tissues of mussels cultivated on a mollusk farm. Multivariate analysis showed significant differences in the overall distribution of the elements among the body parts and sampling sites under consideration. The trace element contents in soft tissues of M. galloprovincialis decreased in the following order: Zn > Cu > As > Ni > Pb > Cd > Cr > Co > Hg. The noncarcinogenic hazard index from the cultivated mussel consumption was found to be well below one and the carcinogenic risk index was found within the tolerable limits, which indicate the safety of consuming these mussels for humans. Byssus of M. galloprovincialis was characterized as a perfect indicator of marine environment pollution with Ni, Cu, Pb, Сo, and Cr. For the first time, the concentrations of trace elements were determined in the shell liquor and the function of byssus and shell liquor as the systems of trace element excretion from soft tissues was demonstrated.

Mercury (Hg) is one of the most hazardous pollutants, due to its toxicity, biological magnification and worldwide persistence in aquatic systems. Thus, new efficient nanotechnologies (e.g. graphene oxide functionalized with polyethyleneimine (GO-PEI)) have been developed to remove this metal from the water. Aquatic environments, in particular transitional systems, are also subjected to disturbances resulting from climate change, such as salinity shifts. Salinity is one of the most relevant factors that influences the distribution and survival of aquatic species such as mussels. To our knowledge, no studies assessed the ecotoxicological impairments induced in marine organisms exposed to remediate seawater (RSW) under different salinity levels. For this, the focus of the present study was to evaluate the effects of seawater previously contaminated with Hg and remediated with GO-PEI, using the species Mytilus galloprovincialis, maintained at three different salinities (30, 20 and 40). The results obtained demonstrated similar histopathological and metabolic alterations, oxidative stress and neurotoxicity in mussels under RSW treatment at stressful salinity conditions (20 and 40) in comparison to control salinity (30). On the other hand, the present findings revealed toxicological effects including cellular damage and histopathological impairments in mussels exposed to Hg contaminated seawater in comparison to non-contaminated ones, at each salinity level. Overall, these results confirm the high efficiency of GO-PEI to sorb Hg from water with no noticeable toxic effects even under different salinities, leading to consider it a promising eco-friendly approach to remediate contaminated water.