Micronuclei and other nuclear abnormalities in mussels (Mytilus galloprovincialis) as biomarkers of cyto-genotoxic pollution in mediterranean waters

Morphological and functional alterations in hemocytes of Mytilus galloprovincialis exposed in high-impact anthropogenic sites

The work aimed to study the induction of morphological alterations in M. galloprovincialis in the field and its suitability to be integrated into a sensitive, simple, and cost-effective cell-based multimarker approach for the detection of the stress status induced by pollution in coastal marine environments in view of ecotoxicological biomonitoring and assessment application. Cellular morphometric alterations was paralleled by the analysis of standardized biomarkers such as lysosomal membrane destabilization, and genotoxocity biomarkers such as micronuclei and binuclated cells frequencies were investigated. The study was carried out by means of a transplanting experiment in the field, using caged organisms from an initial population exposed in the field in two multi-impacted coastal sites of the central Mediterranean area, Bagnoli in the eastern Tyrrhenian Sea and Augusta-Melilli-Priolo in the western Ionian Sea. Capo Miseno (NA) for the Tyrrhenian area and Brucoli (ME) for the Ionian area were chosen as control sites. Hemocyte enlargement and filopodial elongation increased frequencies were observed in organisms exposed to the impacted sites. These morphometric alterations showed strong agreement with the lysosomal membrane destabilization and biomarkers of genotoxicity, suggesting their usefulness in detecting the pollutant-induced stress syndrome related to genotoxic damage.

10-year time course of Hg and organic compounds in Augusta Bay: Bioavailability and biological effects in marine organisms

In the last century, many Mediterranean coastal areas have been subjected to anthropogenic disturbances from industrial activities, uncontrolled landfills, shipyards, and high maritime traffic. The Augusta Bay (eastern Sicily, Italy) represents an example of a strongly impacted coastal environment with an elevated level of sediments contamination due to the presence of one of the largest European petrochemical plants, combined with an extensive commercial and military harbor. The most significant contaminants were represented by mercury (Hg) and hexachlorobenzene (HCB), derived from a former chlor-alkali plant, and other organic compounds like polycyclic aromatic hydrocarbons (PAHs) and polychlorobiphenyls (PCBs). Since the 1970s, Augusta Bay has become internationally recognized as a contaminated marine environment, although very little information is available regarding the temporal trend of contaminants bioavailability and biological impacts on aquatic organisms. In this study, the Hg and HCB concentrations were investigated over 10 years (from 2003 to 2013) in sediments and invertebrate and vertebrate organisms; these two contaminants' ecotoxicity was further evaluated at a biochemical and cellular level by analyzing the induction of organic biotransformation processes and DNA damages. The results showed high concentrations of Hg and HCB in sediments and their strong bioaccumulation in different species with significantly higher values than those measured in reference sites. This trend was paralleled by increased micronuclei frequency (DNA damage biomarker) and activity of the biotransformation system. While levels of chemicals in sediments remained elevated during the time course, their bioavailability and biological effects showed a gradual decrease after 2003, when the chlor-alkali plant was closed. Environmental persistence of Hg and HCB availability facilitates their bioaccumulation and affects the health status of marine organisms, with possible implications for environmental risk, pollutants transfer, and human health.

1,1,1-trichloro-2,2-bis (p-chlorophenyl)-ethane (DDT) and 1,1-Dichloro-2,2-bis (p, p'-chlorophenyl) ethylene (DDE) as endocrine disruptors in human and wildlife: A possible implication of mitochondria

1,1,1-trichloro-2,2-bis (p-chlorophenyl)-ethane (DDT) and its main metabolite 1,1-Dichloro-2,2-bis (p, p'-chlorophenyl) ethylene (DDE) act as endocrine disruptors in humans and wildlife. Immunomodulatory functions have also been attributed to both xenobiotics. DDT was banned in the 1970s due to its toxicity, but it is still produced and used for indoor residual spraying with disease vector control purposes. Due to their persistence and lipophilic properties, DDT and DDE can bioaccumulate through the food chain, being stored in organisms' adipose depots. Their endocrine disruptor function is mediated by agonist or antagonist interaction with nuclear receptors. Present review aimed to provide an overview of how DDT and DDE exposure impacts reproductive and immune systems with estrogen-disrupting action in humans and wildlife. Studies showing DDT and DDE impact on mitochondrial function and apoptosis pathway will also be reviewed, suggesting the hypothesis of direct action on mitochondrial steroid receptors.

Cellular Responses Induced by Zinc in Zebra Mussel Haemocytes. Loss of DNA Integrity as a Cellular Mechanism to Evaluate the Suitability of Nanocellulose-Based Materials in Nanoremediation

Zinc environmental levels are increasing due to human activities, posing a threat to ecosystems and human health. Therefore, new tools able to remediate Zn contamination in freshwater are highly recommended. Specimens of Dreissena polymorpha (zebra mussel) were exposed for 48 h and 7 days to a wide range of ZnCl2 nominal concentrations (1-10-50-100 mg/L), including those environmentally relevant. Cellulose-based nanosponges (CNS) were also tested to assess their safety and suitability for Zn removal from freshwater. Zebra mussels were exposed to 50 mg/L ZnCl2 alone or incubated with 1.25 g/L of CNS (2 h) and then removed by filtration. The effect of Zn decontamination induced by CNS has been verified by the acute toxicity bioassay Microtox®. DNA primary damage was investigated by the Comet assay; micronuclei frequency and nuclear morphological alterations were assessed by Cytome assay in mussels' haemocytes. The results confirmed the genotoxic effect of ZnCl2 in zebra mussel haemocytes at 48 h and 7-day exposure time. Zinc concentrations were measured in CNS, suggesting that cellulose-based nanosponges were able to remove Zn(II) by reducing its levels in exposure waters and soft tissues of D. polymorpha in agreement with the observed restoration of genetic damage exerted by zinc exposure alone.

Environmental Genotoxicity Assessment Using Micronucleus (and Nuclear Abnormalities) Test on Intertidal Mussel Perumytilus purpuratus: A Tool for Biomonitoring the Chilean Coast

The release of pollutants is increasing along the coast of Chile, and the use of biomarkers in biomonitoring programs is essential to assess the early biological effects of marine contamination. The Micronucleus (MN) test was carried out using hemocytes of the mussel Perumytilus purpuratus from two sites in northern-central Chile (La Pampilla and Totoralillo). Nuclear abnormalities were assessed, and high frequencies of micronucleus (10.7-14.4‰) and other abnormalities were found (51.9-76.6‰). These values tended to be higher in La Pampilla, possibly due to the large presence of pollution sources in that site. However, considerably high values were observed in both sites. P. purpuratus is a suitable bioindicator and further monitoring along the Chilean coast using this species should be developed using the MN test and/or other biomarkers to comprehend the effects of human activities on the coastal environment of Chile.

Sampling Site Specific Biomarker Responses in Mediterranean Mussels from the Adriatic Sea

This study aims to explore the spatial and temporal patterns in biomarker responses during early spring and late summer in Mytilus galloprovincialis using samples from two Adriatic Sea ecosystems between 2009 and 2012. The condition index was higher in September at all sampling sites and suggests that mussels can store energy during summer for wintertime spawning and survival through the winter. Over the entire study period, higher values of metallothioneins indicated sites with higher levels of heavy metals (Boka Kotorska Bay), while acetylcholine esterase activity was inhibited at the Gulf of Trieste. Genotoxicity was similar among sampling sites. We summarized biomarker responses in a stress index, IBRv2, and found that sampling sites in the Gulf of Trieste had lower stress levels while the highest stress levels were detected in the Boka Kotorska Bay.

Effect-Based Approach to Assess Nanostructured Cellulose Sponge Removal Efficacy of Zinc Ions from Seawater to Prevent Ecological Risks

To encourage the applicability of nano-adsorbent materials for heavy metal ion removal from seawater and limit any potential side effects for marine organisms, an ecotoxicological evaluation based on a biological effect-based approach is presented. ZnCl2 (10 mg L-1) contaminated artificial seawater (ASW) was treated with newly developed eco-friendly cellulose-based nanosponges (CNS) (1.25 g L-1 for 2 h), and the cellular and tissue responses of marine mussel Mytilus galloprovincialis were measured before and after CNS treatment. A control group (ASW only) and a negative control group (CNS in ASW) were also tested. Methods: A significant recovery of Zn-induced damages in circulating immune and gill cells and mantle edges was observed in mussels exposed after CNS treatment. Genetic and chromosomal damages reversed to control levels in mussels' gill cells (DNA integrity level, nuclear abnormalities and apoptotic cells) and hemocytes (micronuclei), in which a recovery of lysosomal membrane stability (LMS) was also observed. Damage to syphons, loss of cilia by mantle edge epithelial cells and an increase in mucous cells in ZnCl2-exposed mussels were absent in specimens after CNS treatment, in which the mantle histology resembled that of the controls. No effects were observed in mussels exposed to CNS alone. As further proof of CNS' ability to remove Zn(II) from ASW, a significant reduction of >90% of Zn levels in ASW after CNS treatment was observed (from 6.006 to 0.510 mg L-1). Ecotoxicological evaluation confirmed the ability of CNS to remove Zn from ASW by showing a full recovery of Zn-induced toxicological responses to the levels of mussels exposed to ASW only (controls). An effect-based approach was thus proven to be useful in order to further support the environmentally safe (ecosafety) application of CNS for heavy metal removal from seawater.

Biomarker responses and accumulation of polycyclic aromatic hydrocarbons in Mytilus trossulus and Gammarus oceanicus during exposure to crude oil

In the brackish water Baltic Sea, oil pollution is an ever-present and significant environmental threat mainly due to the continuously increasing volume of oil transport in the area. In this study, effects of exposure to crude oil on two common Baltic Sea species, the mussel Mytilus trossulus and the amphipod Gammarus oceanicus, were investigated. The species were exposed for various time periods (M. trossulus 4, 7, and 14 days, G. oceanicus 4 and 11 days) to three oil concentrations (0.003, 0.04, and 0.30 mg L^-1 based on water measurements, nominally aimed at 0.015, 0.120, and 0.750 mg L^-1) obtained by mechanical dispersion (oil droplets). Biological effects of oil exposure were examined using a battery of biomarkers consisting of enzymes of the antioxidant defense system (ADS), lipid peroxidation, phase II detoxification (glutathione S-transferase), neurotoxicity (acetylcholinesterase inhibition), and geno- and cytotoxicity (micronuclei and other nuclear deformities). In mussels, the results on biomarker responses were examined in connection with data on the tissue accumulation of polycyclic aromatic hydrocarbons (PAH). In M. trossulus, during the first 4 days of exposure the accumulation of all PAHs in the two highest exposure concentrations was high and was thereafter reduced significantly. Significant increase in ADS responses was observed in M. trossulus at 4 and 7 days of exposure. At day 14, significantly elevated levels of geno- and cytotoxicity were detected in mussels. In G. oceanicus, the ADS responses followed a similar pattern to those recorded in M. trossulus at day 4; however, in G. oceanicus, the elevated ADS response was still maintained at day 11. Conclusively, the results obtained show marked biomarker responses in both study species under conceivable, environmentally realistic oil-in-seawater concentrations during an oil spill, and in mussels, they are related to the observed tissue accumulation of oil-derived compounds.

Lysosomal Membrane Stability in Hemocytes and Micronuclei in Gills of Perumytilus purpuratus Lamarck 1819 (Bivalvia: Mytilidae) Exposed to Copper

The aim of this study was to determine the cytotoxic and genotoxic effects of copper on the bivalve Perumytilus purpuratus. The individuals were exposed to three copper concentrations: 1, 30 and 45 μg L^-1 for 24, 48 and 96 h. Lysosomal membrane stability in hemocytes was determined through the neutral red retention time (NRRT) and micronucleus (MN) frequency tests in hemocytes and gills. The results show that the NRRT decreased significantly at 30 μg L^-1 after 48 h of exposure. The frequency of MN was significantly greater in gills after 24 h in all concentrations tested. Copper is cytotoxic from 30 μg L^-1 and genotoxic from 1 μg L^-1. The use of these biomarkers of effects in P. purpuratus is proposed as an early warning tool for monitoring in environmental assessment of coastal ecosystems impacted by mining activities.

First report on the mutagenicity and cytotoxicity of Zno nanoparticles in reptiles

Understanding how human activities affect animal biodiversity is essential to investigations about the biological effects of several pollutants and contaminants dispersed in the environment. This is the case of zinc oxide nanoparticles (ZnO NPs), which are emerging pollutants whose effect on reptiles' health is completely unknown. Thus, the objective of the present study is to evaluate the possible damages induced by these NPs in Podocnemis expansa juveniles (Amazon turtle) by using morphological changes of circulating erythrocytes as nuclear toxicity biomarker. The animals were exposed to the intramuscular administration of 440 μg/kg and 440,000 μg/kg of ZnO NPs, for 10 consecutive days. The micronuclei assay and other nuclear abnormalities were performed at the end of the experiment, as well as different morphometric measurements applied to the erythrocytes. Based on the current data, ZnO NPs induced nuclear abnormalities such as micronuclei and binucleation, which are associated with carcinogenic processes and with flaws in the mitotic machinery. The low "nuclear area: erythrocyte area" ratio and larger cytoplasmic area observed for animals exposed to NPs evidenced erythrocytic change induction likely related to negative energy balance/metabolism interferences and/or to oxygen transportation efficiency by erythrocytes. This is the first report on the mutagenic and cytotoxic effect induced by NPs on representatives of a group of reptiles. This outcome suggests that further investigations must focus on better understanding the (eco)toxicological potential of ZnO NPs.

An insight on the mutagenicity and cytotoxicity of zinc oxide nanoparticles in Gallus gallus domesticus (Phasianidae)

Although the toxicity of zinc oxide (ZnO) nanoparticles (NPs) is known in several experimental models, little is known about their effects on bird representatives. Therefore, the aim of the current study is to evaluate the mutagenic and cytotoxic potential of ZnO NPs in chicks belonging to species Gallus gallus domesticus, as well as to analyze the role played by nuclear and erythrocyte morphological changes as biomarkers of the toxicity of these nanopollutants. Two doses of ZnO NPs (0.245 mg k^-1 and 245.26 mg kg^-1) were herein tested; they were determined based on the predictive environmental concentration of these NPs (760 μg L-1), on the body biomass of the analyzed animals and on the mean daily water intake/bird. Birds were subjected to two intraperitoneal applications (one per day) of solution containing ZnO NPs; they were euthanized 48 h after the first application. The herein collected data have shown that NPs were capable of inducing the formation of different types of erythrocyte nuclear abnormalities, such as micronucleus, binucleate erythrocytes, blebbed, reniform and multilobulated nuclei, as well as symmetric and asymmetric constriction. In addition, changes in the size and shape of erythrocytes were observed in birds exposed to ZnO NPs. Zn bioaccumulation analysis conducted in brain tissues confirmed the association between these changes and animal exposure to ZnO NPs. Thus, besides confirming the toxicological potential of ZnO NPs, to the best of our knowledge, the current study is the first report on the mutagenic and cytotoxic effects of these NPs on bird representatives.

Micronucleus Experiments with Bivalve Molluscs

The micronucleus (MN) test, as an index of accumulated DNA damage during the lifespan of cells, is the most applied assay in aquatic animals to assess the exposure to a complex mixture of genotoxic pollutants. An increase in MN frequency was reported on mussels exposed to the most common environmental pollutants under laboratory conditions, such as heavy metals, polycyclic aromatic hydrocarbons, and ionizing radiation. The test was applied in a large number of biomonitoring studies in different geographic areas to identify the exposure to different classes of pollutants with good discrimination power and to evaluate the recovery effects after accidental pollution events. A standardized MN assay protocol in hemocytes and gill cells for use in bivalve species, including scoring of different cell types, necrotic and apoptotic cells and nuclear anomalies, was established following the “cytome approach”. The mussel MNcytome (MUMNcyt) assay, using the proposed detailed criteria for the identification of cell types, is suitable for application in experimental studies under controlled conditions and in biomonitoring programs in aquatic environments.

Metabolomic responses of mussel Mytilus galloprovincialis to fluoranthene exposure under different nutritive conditions

Biomarkers are useful tools to assess biological effects of pollutants that are extensively used in monitoring programs to assess ecosystem health. However, they are strongly affected by mussel physiological state, especially nutritive status, which has led to the search of new biological indicators of chemical pollutants exposition. Environmental metabolomics is an approach for examining the metabolic responses (measurement of low molecular weight endogenous metabolites) of an organism to both natural and anthropogenic stressors that can occur in its environment. The aim of the present work was to assess the effect of the polycyclic aromatic hydrocarbon fluoranthene (FLU) exposure on the metabolomic profiles of mussel digestive glands under different nutritive conditions. To achieve this objective, mussels were reared, for a period of 56 days, under three different food rations in order to obtain a gradient of nutritive status (negative, zero and positive energy balance), and after that, they were exposed, during 3 weeks, to a nominal concentration of 3 μg FLU L^-1. A total of 43 metabolites, including aminoacids (Ala, Val, Leu, Ile, etc.), energy metabolism related metabolites (ATP, AMP, etc.), organic osmolytes (taurine, etc.), redox metabolism (GSH, NADP+) and nucleotides, were identified and quantified in the digestive glands of the mussels. Principal Component Analysis (PCA) defined two principal components (PC1 and PC2) that explained 55.6% of the total variance, although the first component explains more than 80% of this variance, this being related to the mussel nutritive condition. The effect of the toxicant, explained by the PC2, is similar to that produced under conditions of food restriction, which masks the effect of the toxicant under these conditions. As the feeding conditions are more favorable, the toxic effect becomes more apparent. Therefore, the great influence of nutritive condition on mussel metabolome implies a handicap for the use of metabolomic biomarkers, as previously demonstrated for biochemical and other molecular biomarkers, in large-scale monitoring programs in which several food conditions coexist with pollution levels.

Baseline levels of environmental genotoxicity and potential confounding factors using common sole (Solea solea) as sentinel organism

Micronuclei (MN) and nuclear buds (NB) frequency was assessed monthly over a one-year period in erythrocytes of common soles (Solea solea) from the Basque continental shelf, a minor disturbed area, in order to determine baseline levels and potential biotic and abiotic confounding factors within biomonitoring purposes. Both genotoxic parameters presented seasonal variations, although only NB frequency was positively correlated with environmental variables (i.e. water temperature and salinity). On the contrary, MN and NB were not affected by age and gender. Therefore, samples of combined age and gender can be used for biomonitoring genotoxic effects, although sampling period together with water temperature and salinity should be thoroughly considered for NB. Overall, these findings are the first attempt to establish baseline MN (0.10-0.78‰) and NB (0.13-0.82‰) frequencies in common sole from Basque marine waters, which are useful for upcoming data comparisons and integration within genotoxicity evaluation procedures of similar marine environments under biomonitoring scopes.

Assessment of contaminant concentrations in sediments, fish and mussels sampled from the North Atlantic and European regional seas within the ICON project

Understanding the status of contaminants in the marine environment is a requirement of European Union Directives and the Regional Seas Conventions, so that measures to reduce pollution can be identified and their efficacy assessed. The international ICON workshop (Hylland et al., in this issue) was developed in order to test an integrated approach to assessing both contaminant concentrations and their effects. This paper describes and assesses the concentrations of trace metals, polycyclic aromatic hydrocarbons, and polychlorinated biphenyls in sediments, mussels, and fish collected from estuarine, coastal and offshore waters from Iceland to the Mediterranean Sea. For organic contaminants, concentrations progressively increased from Iceland, to the offshore North Sea, to the coastal seas, and were highest in estuaries. Metals had a more complex distribution, reflecting local anthropogenic inputs, natural sources and hydrological conditions. Use of internationally recognised assessment criteria indicated that at no site were concentrations of all contaminants at background and that concentrations of some contaminants were of significant concern in all areas, except the central North Sea.

The mussel caging approach in assessing biological effects of wastewater treatment plant discharges in the Gulf of Finland (Baltic Sea)

Biological effects of wastewater treatment plant (WWTP) effluents were investigated in Baltic mussels (Mytilus trossulus) caged for one month 800m and 1100m from the WWTP discharge site and at a reference site 4km away. Significant antioxidant, genotoxic and lysosomal responses were observed close to the point of the WWTP discharge. Passive samplers (POCIS) attached to the cages indicated markedly higher water concentrations of various pharmaceuticals at the two most impacted sites. Modeling the dispersal of a hypothetical passive tracer compound from the WWTP discharge site revealed differing frequencies and timing of the exposure periods at different caging sites. The study demonstrated for the first time the effectiveness of the mussel caging approach in combination with passive samplers and the application of passive tracer modeling to examine the true exposure patterns at point source sites such as WWTP pipe discharges in the Baltic Sea.

Assessment of pollution level using Mytilus galloprovincialis as a bioindicator species: The case of the Gulf of Trieste

A multidisciplinary approach was used to estimate the pollution level of the marine environment in the North Eastern Adriatic by measurement of the isotopic composition of carbon and nitrogen (δ(13)C, δ(15)N), metal/metalloids analyses (Fe, Cu, Zn, As, Se, Cd and Pb, including As speciation) in the Mytilus galloprovincialis, as well by using metallothioneins (MT) concentrations, micronuclei (MN) in gill cells and biological parameters (condition index and gonadosomatic index). Concentrations of MT were in the range from 44 to 175 μg g(-1) wet matter tissue and were higher at the end of the winter season. The frequency of MN did not indicate an elevated level. Sewage sludge pollution was not confirmed. Elevated As concentrations in mussel are related to salinity and low nutrients concentrations and not to pollution. Elevated concentrations of Cu, Zn and Pb were found in the Bay of Koper in comparison with the Bays of Strunjan and Piran.

A multibiomarker approach to the assessment of pollution impacts in two Baltic Sea coastal areas in Sweden using caged mussels (Mytilus trossulus)

Blue mussels (Mytilus trossulus) were transplanted in cages for three months in two Swedish coastal areas in the Bothnian Sea (northern Baltic Sea) to investigate the interactions between analysed environmental chemicals and biological responses. A wide array of biological parameters (biomarkers) including antioxidant and biotransformation activity, geno-, cyto- and neurotoxic effects, phagocytosis, bioenergetic status and heart rate were measured to detect the possible effects of contaminants. Integrated Biomarker Response index and Principal Component Analysis performed on the individual biological response data were able to discriminate between the two study areas as well as the contaminated sites from their respective local reference sites. The two contaminated sites outside the cities of Sundsvall (station S1) and Gävle (station G1) were characterised by different biomarker response patterns. Mussels at station S1 showed a low condition index, increased heart rate recovery time and phagocytosis activity coinciding with the highest tissue concentrations of some trace metals, polycyclic aromatic hydrocarbons and organotins. At station G1 the highest organochlorine pesticide concentration was recorded as well as elevations in glutathione S-transferase activity, thiamine content and low lysosomal membrane stability. Significant variability in the geno- and cytotoxic responses and bioenergetic status was also observed at the different caging stations. The results obtained suggest that different chemical mixtures present in the study areas cause variable biological response patterns in organisms.

DNA damage and transcriptional changes in the gills of mytilus galloprovincialis exposed to nanomolar doses of combined metal salts (Cd, Cu, Hg)

Aiming at an integrated and mechanistic view of the early biological effects of selected metals in the marine sentinel organism Mytilus galloprovincialis, we exposed mussels for 48 hours to 50, 100 and 200 nM solutions of equimolar Cd, Cu and Hg salts and measured cytological and molecular biomarkers in parallel. Focusing on the mussel gills, first target of toxic water contaminants and actively proliferating tissue, we detected significant dose-related increases of cells with micronuclei and other nuclear abnormalities in the treated mussels, with differences in the bioconcentration of the three metals determined in the mussel flesh by atomic absorption spectrometry. Gene expression profiles, determined in the same individual gills in parallel, revealed some transcriptional changes at the 50 nM dose, and substantial increases of differentially expressed genes at the 100 and 200 nM doses, with roughly similar amounts of up- and down-regulated genes. The functional annotation of gill transcripts with consistent expression trends and significantly altered at least in one dose point disclosed the complexity of the induced cell response. The most evident transcriptional changes concerned protein synthesis and turnover, ion homeostasis, cell cycle regulation and apoptosis, and intracellular trafficking (transcript sequences denoting heat shock proteins, metal binding thioneins, sequestosome 1 and proteasome subunits, and GADD45 exemplify up-regulated genes while transcript sequences denoting actin, tubulins and the apoptosis inhibitor 1 exemplify down-regulated genes). Overall, nanomolar doses of co-occurring free metal ions have induced significant structural and functional changes in the mussel gills: the intensity of response to the stimulus measured in laboratory supports the additional validation of molecular markers of metal exposure to be used in Mussel Watch programs.

Health status of red mullets from polluted areas of the Spanish Mediterranean coast, with special reference to Portmán (SE Spain)

A suite of general physiological indicators and hepatic biomarker responses were determined in red mullet (Mullus barbatus) from priority pollution areas of W Mediterranean Sea, including the highly metal polluted area of Portmán (Cartagena, SE Spain). Concentrations of metals and persistent organic pollutants in fish muscle tissue and sediment samples were also analysed. Our results showed that fish from Portmán accumulated the highest concentrations of mercury, lead and arsenic and also of some polycyclic aromatic hydrocarbons and polychlorinated biphenyls congeners. In addition, they had significantly lower condition factor, muscle lipid content and gonadosomatic index, as well as the lowest levels of DNA integrity and the highest ethoxyresorufin-O-deethylase (EROD) activity in liver of the areas investigated. Contaminant body burden in fish only partly corresponded to chemical characteristics of the sediments in the areas in which they were collected. Our findings indicate that red mullets from Portmán had suboptimal health status that warrant further study.

Assessment of the mechanisms of detoxification of chemical compounds and antioxidant enzymes in the digestive gland of mussels, Mytilus galloprovincialis, from Mediterranean coastal sites

In this study the effects of the main marine pollutants (metals, PAHs, PCBs and DDTs) were assessed in native mussels from the Mediterranean coast of Spain. For this purpose several biomarkers such as benzo[a]pyrene hydroxylase (BPH), DT-diaphorase (DTD), glutathione S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidases (GPs), glutathione reductase (GR), metallothionein (MT) and lipid peroxidation (LPO) were measured in the digestive gland. Results showed increased LPO levels in mussels which accumulated high loads of organic compounds and arsenic in their tissues. BPH levels correlated to the concentrations of organic compounds in mussel tissues, though the range of BPH response was low in relation to the high gradient of accumulation of organic pollutants. Increased BPH levels, concomitant to low DTD and GST activities, were detected in mussels which presented high levels of organic pollutants in their tissues. This suggests that signs of LPO present in these organisms are related to the imbalance between phase I and phase II biotransformation processes. Furthermore, the increased levels of MT and CAT detected in mussels which showed high levels of Cd in their tissues appear to reflect a coordinated response which protects against the toxicity of this metal. The application of these biomarkers in environmental assessment is discussed.