Dual oxidative stress and fatty acid profile impacts in Paracentrotus lividus exposed to lambda-cyhalothrin: biochemical and histopathological responses.

Lambda-cyhalothrin (λ-cyh) is a potential pyrethroid insecticide widely used in pest control. The presence of pyrethroids in the aquatic ecosystem may induce adverse effects on non-target organisms such as the sea urchin. This study was conducted to assess the toxic effects of λ-cyh on the fatty acid profiles, redox status, and histopathological aspects of Paracentrotus lividus gonads following exposure to three concentrations of λ-cyh (100, 250 and 500 µg/L) for 72 h. The results showed a significant decrease in saturated fatty acid (SFAs) with an increase in monounsaturated fatty acid (MUFAs) and polyunsaturated fatty acid (PUFAs) levels in λ-cyh treated sea urchins. The highest levels in PUFAs were recorded in the eicosapentaenoic acids (C20:5n-3), docosahexaenoic acids (C22:6n-3) and arachidonic acids (C20:4n-6) levels. The λ-cyh intoxication promoted oxidative stress with an increase in hydrogen peroxide (H2O2), malondialdehyde (MDA) and advanced oxidation protein products (AOPP) levels. Furthermore, the enzymatic activities and non-enzymatic antioxidants levels were enhanced in all exposed sea urchins, while the vitamin C levels were decreased in 100 and 500 µg/L treated groups. Our biochemical results have been confirmed by the histopathological observations. Collectively, our findings offered valuable insights into the importance of assessing fatty acids' profiles as a relevant tool in aquatic ecotoxicological studies.

New insight into the toxic effects of lithium in the ragworm Perinereis cultrifera as revealed by lipidomic biomarkers, redox status, and histopathological features.

Lithium (Li) is a toxic monovalent alkaline metal used in household items common to industrial applications. The present work was aimed at investigating the potential toxic effects of LiCl on the redox status, fatty acid composition, and histological aspects of the marine ragworm Perinereis cultrifera. Sea worms were exposed to LiCl graded doses (20, 40, and 80 mg/L) for 48 h. Compared with the control group, the saturated fatty acids (SFA) decreased while monounsaturated (MUFA) and polyunsaturated fatty acids (PUFA) increased upon exposure to LiCl. The increase in PUFA n-3 and PUFA n-6 was concomitant to an increase in docosahexaenoic (DHA: C22:6n-3), eicosapentaenoic (EPA: C20:5n-3), and docosapentaenoic acid (C22:5n-6) fatty acids. Results showed that LiCl-treated specimens accumulate lithium with increasing exposure gradient. Indeed, the exposure to LiCl doses promoted oxidative stress with an increase of the ferric reducing antioxidant power (FRAP), malondialdehyde (MDA), hydrogen peroxide (H2O2), advanced oxidation protein product (AOPP), and protein carbonyl (PCO) as well as the enzymatic and non-enzymatic antioxidants (non-protein thiols (NPSH), catalase (CAT), superoxide dismutase (SOD), reduced glutathione (GSH), glutathione peroxidase (GPx), glutathione S-transferase (GST), and metallothionein (MT)) levels in all treated groups. Our biochemical findings have been affirmed by the histopathological observations showing hyperplasia and loss of the intestine structure in treated specimens. Overall, our findings give new insights on the toxic effect of LiCl on the redox status of P. cultrifera body tissue and highlighted the usefulness of the FA composition as an early sensitive bioindicators to better understand LiCl mechanism of toxicity in marine polychaetes.

Preliminary inter-port study of the quality of environments using physiological responses of invertebrates exposed to chronic trace element and organic contamination in Corsica (Mediterranean Sea).

Port areas are socio-ecosystems impacted by chronic mixture pollution. Some marine species benefit from living there and may be studied to define the ecological state of such environments. In this study, the risks of chronic chemical contamination and its consequences on three marine molluscs were evaluated in North Corsica (France) port areas. Mediterranean mussel Mytilus galloprovincialis, tubular sea cucumber Holothuria tubulosa and Mediterranean limpet Patella sp. were sampled in three port areas and a reference location. A set of biomarkers was analysed to evaluate oxidative stress, detoxification, energetic metabolism, neurotoxicity, immunity and bioaccumulation (metallic trace elements and organic pollutants). The objectives were to assess pollution-induced effects in organisms, to determine the best bioindicator species for the selected locations and to validate a "pool" sampling technique (when the analysis is done on a single pool of samples and not on individual samples). The results validate the sampling techniques as "pool" for management purposes. St-Florent was demonstrated as the most contaminated location. All the other locations present a low contamination, below the recommended threshold values (for metallic trace elements and organic pollutants). Finally, the limpet appears to be the best bioindicator for the selected locations. Mussel and sea cucumber are inappropriate due to their absence in this oligotrophic region and the lack of responses observed, respectively.

Active and passive biomonitoring of trace elements, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in small Mediterranean harbours.

Pollution particularly affects coastal ecosystems due to their proximity to anthropic sources. Among those environments, harbours are subjected to marine traffic but also to accidental and chronic pollution. These areas are thus exposed to complex mixtures of contaminants such as trace elements and organic contaminants which can impact marine species, habitats, and ecosystem services. The monitoring of these compounds is thus a crucial issue for assessment of environmental health. In this context, the aim of the present work was to evaluate the chemical contamination of harbours in Corsica (NW Mediterranean) by measuring the bioaccumulation of trace elements, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in mussels, limpets, and sea cucumbers. The human health risks associated with seafood consumption were also assessed. Results reveal a relatively low contamination in the Corsican harbours studied compared to larger Mediterranean ports and suggest that the potential health risk for consumers eating seafood is low.

First characterization of seasonal variations in biomarkers baseline in Patella sp. from Mediterranean ports (North Corsica, France).

In port areas the identification of contamination sources is necessary for an efficient management. Biomonitoring provides information on the environmental impact of the pollutants. It is often difficult to differentiate the natural variations of biomarkers from those induced by pollution. The present study aims to define a baseline level for biochemical biomarkers in limpet (Patella sp.) collected in four North-Corsica port areas. Reference data for five biomarkers (superoxide dismutase, glutathione S-transferase, laccase, pyruvate kinase and acetylcholinesterase) were described in a model, using length of the limpet shell, temperature and salinity. The measured biomarkers responses on potentially polluted sites usually fell within the range of the expected values for an unaffected site, suggesting that a main part of the variations is explained by environmental conditions. Not included in the model, biological factors (sex, development stage, etc.), annual variation or other physico-chemical parameter could explain the variations in the model.

A multi-approach inventory of the blue carbon stocks of Posidonia oceanica seagrass meadows: Large scale application in Calvi Bay (Corsica, NW Mediterranean).

In Mediterranean, Posidonia oceanica develops a belowground complex structure ('matte') able to store large amounts of carbon over thousands of years. The inventory of blue carbon stocks requires the coupling of mapping techniques and in situ sediment sampling to assess the size and the variability of these stocks. This study aims to quantify the organic (Corg) and inorganic (Cinorg) carbon stocks in the P. oceanica matte of the Calvi Bay (Corsica) using sub-bottom profiler imagery and biogeochemical analysis of sediment cores. The matte thicknesses map (average ± SD: 2.2 m ± 0.4 m) coupled with marine benthic habitat cartography allows to estimate matte volume at 12 473 352 m3. The cumulative stocks were assessed at 20.2-50.3 kg Corg m-2 and 26.6-58.7 kg Cinorg m-2 within the first meter of depth on matte (3632 ± 486 cal yr BP). The data contributed to estimate the overall carbon stocks at 389 994 t Corg and 615 558 t Cinorg, offering a new insight of the heterogeneity of blue carbon stocks in seagrass meadows. Variability of carbon storage capacity of matte influenced by substrate is discussed.

Ecological and human health risk assessment of potentially toxic element contamination in waters of a former asbestos mine (Canari, Mediterranean Sea): implications for management.

Between 1948 and 1965, the Canari asbestos mine (Corsica, France) discharged 11 million tonnes of serpentinite rubble into the sea. This study, therefore, aims to assess the environmental and health risks associated with contamination of potentially toxic elements using bioindicators (seagrass and fish) in the areas bordering the former mine within the perimeter of the Cap Corse and Agriate Marine Natural Park. The results and multivariate statistical analyses of the potentially toxic elements, made it possible to identify a concentration gradient, a model of bioaccumulation, and the occurrence of different groups, thus reflecting a spatial variation of the contamination. These results indicate that the former asbestos mine can still be considered, 55 years after its closure, as a major source of Co, Cr, and Ni for marine ecosystems and still influences the quality of the coastal area today. Our study, therefore, indicates that the two most polluted sites (Albo and Negru) are the closest stations to the south of the old Canary asbestos mine. According to the Trace Elements Pollution Index (TEPI) values, 6 species were classified as having a high contamination level: Scorpaena notata (1.37), Scorpaena porcus (1.36), Sepia officinalis (1.27), Diplodus vulgaris (1.02), Spicara maena (0.95), and Mullus surmuletus (0.94). Regarding the potentially toxic elements measured in the edible tissues of fish, the concentrations were all below the regulatory thresholds and did not reveal any potential risk to human health (Cd, Cu, Fe, Pb, Se, Sn, Zn). This work provides new and useful information to improve the monitoring of the environmental quality of a region characterized by previous mining activity and to assess the potential risk to human health due to the consumption of fish. Beyond the purely scientific aspects, these results could serve as decision support at the regional level for the definition of long-term public policies.

First insight into the development of a new transcriptomic tool in French Corsica harbors.

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.

Trace elements and oxidative stress in the Ark shell Arca noae from a Mediterranean coastal lagoon (Bizerte lagoon, Tunisia): are there health risks associated with their consumption?

The current study examined the concentrations of ten trace elements (TE) (nickel, chromium, cadmium, iron, zinc, manganese, aluminum, copper, selenium and lead) in the edible tissue of the Ark shell Arca noae (L. 1758) from a Mediterranean coastal lagoon, the Bizerte lagoon during 2013-2014. The analysis of several redox status biomarkers, metallothioneins (MTs), malondialdehyde (MDA), glutathione peroxidase (GPx), reduced glutathione (GSH) and acetylcholinesterase (AChE), was monitored as a response to TE bioaccumulation and environmental parameters variability. Significant differences (p < 0.05) were observed between mean seasonal TE concentrations in A. noae soft tissue. The highest TE concentrations in A. noae soft tissues were recorded during summer, which coincided with the increase of body dry weight (BDW) and the gonad index (GI). During this season, biomarker responses were enhanced, revealing significant increases of MTs, MDA and GSH levels as well as GPx activity in A. noae tissues, while a decrease of AChE activity was observed. The levels of TE analyzed in A. noae and several parameters used to assess the potential human risk (estimated weekly intake, target hazard quotient and target hazard risk) were lower than the permissible limits for safe seafood consumption. Consequently, this shellfish can be considered safe for human consumption. This preliminary study presents prospects for the valorization of this seafood product in Tunisia's food sector. It also gives basal information for future environmental assessment studies in which A. noae could be used as early warning tools in the field of biomonitoring programs and confirms the usefulness of biomarkers to monitor the health status of aquatic organisms.

Trace Elements and Fatty Acid Profile of Argyrosomus regius (Asso, 1801) from Mediterranean Aquaculture.

Although Argyrosomus regius (Asso, 1801) counts among the most appreciated and increasingly consumed fish species in Europe, little information is available on its flesh quality. This research concerns both healthy aquatic resource diversification and good nutritional quality. It is the first study to evaluate the quality of A. regius flesh from Mediterranean aquaculture. It aims to assess the concentration of 19 trace elements and to determine the fatty acid profile of this fish farmed in the Mediterranean Sea and to discuss human exposure risks. The nutritional intake of oligoelements (selenium (Se), zinc (Zn), and chromium (Cr)) and the mean concentrations of contaminants (arsenic (As), barium (Ba), cadmium (Cd), lead (Pb), and tin (Sn)) in A. regius muscles are, respectively, above and below recommended regulatory standards set by the international legislation. Additionally, the low fat content in its muscle mass and its high level of docosahexaenoic acid (C22: 6 n-3; DHA) and, to a lesser extent, eicosapentaenoic acid (C20: 5 n-3; EPA) confers satisfying nutritional qualities. This study allowed to conclude that meager can be considered as a source of seafood with good nutritional qualities for human health.

Absence of spatial genetic structure in common dentex (Dentex dentex Linnaeus, 1758) in the Mediterranean Sea as evidenced by nuclear and mitochondrial molecular markers.

The common dentex, Dentex dentex, is a fish species which inhabits marine environments in the Mediterranean and Northeast Atlantic regions. This is an important species from an ecological, economic and conservation perspective, however critical information on its population genetic structure is lacking. Most samples were obtained from the Mediterranean Sea (17 sites) with an emphasis around Corsica (5 sites), plus one Atlantic Ocean site. This provided an opportunity to examine genetic structuring at local and broader scales to provide science based data for the management of fishing stocks in the region. Two mitochondrial regions were examined (D-loop and COI) along with eight microsatellite loci. The COI data was combined with publicly available sequences and demonstrated past misidentification of common dentex. All markers indicated the absence of population genetic structure from the Bay of Biscay to the eastern Mediterranean Sea. Bayesian approaches, as well as the statistical tests performed on the allelic frequencies from microsatellite loci, indicated low differentiation between samples; there was only a slight (p = 0.05) indication of isolation by distance. Common dentex is a marine fish species with a unique panmictic population in the Mediterranean and likely in the Atlantic Ocean as well.

Comparison of elemental composition in two wild and cultured marine fish and potential risks to human health.

Among all available species, fish are a powerful model for risk-benefit assessments to study the effects of contaminants on human health. Gilthead seabream (Sparus aurata, Linnaeus 1758) and european seabass (Dicentrarchus labrax, Linnaeus 1758) are two species of great economic importance, representing very large production volumes in the Mediterranean. The objective of this study is (1) to analyze the concentrations of Trace Elements (TE) between wild and cultured seabream and seabass specimens, (2) to compare the determined concentrations with other studies, and (3) to increase the data about the potential risks to human health. Our results point to significant intra- and interspecies-specific differences between wild and cultured fish for several trace elements. Several strong and moderate inter-elemental correlations in fish muscle were observed through correlation analysis. In our study, the mean levels of trace elements were still below the standard safety values for fish intended for human consumption. The same results were reached for all the parameters analyzed (international legal limits, estimated weekly intake, provisional tolerable weekly intake, target hazard quotient, target cancer risk), with trace element levels in fish below those that could pose a risk to human health. Consequently, these fish can be considered safe for human consumption. A better understanding of the levels of trace elements in fish would also better inform consumers about the potential risks of exposure to contaminants.