This study compared species identity, microplastics, chemical and microbial contamination between consumption mussels and wild type mussels, collected at Belgian department stores and Belgian groynes and quaysides, respectively. Species identification based on genetic analysis showed a high number of Mytilus (M.) edulis compared to M. galloprovincialis and M. edulis/galloprovincialis hybrid mussels. The number of total microplastics varied from 2.6 to 5.1fibres/10g of mussel. A higher prevalence of orange fibres at quaysides is related to fisheries activities. Chemical contamination of polycyclic aromatic hydrocarbons and polychlorobiphenyls could be related to industrial activities and water turbidity, with maximum concentrations at the quayside of port Zeebrugge. The inverse was noted for Escherichia coli contamination, which was relatively low at Zeebrugge quayside with a total count of 3.9×102CFU/100g tissue, due to limited agricultural effluents. Results of this complementary analysis stress the importance of integrated monitoring and quality assessment.

Long-line mussel farming has been proposed as a mitigation tool for removal of excess nutrients in eutrophic coastal waters. A full-scale mussel farm optimized for cost efficient nutrient removal was established in the eutrophic Skive Fjord, Denmark where biological and economic parameters related to nutrient removal was monitored throughout a full production cycle (1yr). The results showed that it was possible to obtain a high area specific biomass of 60tWWha−1eqvivalent to a nitrogen and phosphorus removal of 0.6–0.9 and 0.03–0.04tha−1yr, respectively. The analysis of the costs related to establishment, maintenance and harvest revealed that mussel production optimized for mitigation can be carried out at a lower cost compared to mussel production for (human) consumption. The costs for nutrient removal was 14.8€kg−1N making mitigation mussel production a cost-efficient measure compared to the most expensive land-based measures.

Measuring loads of bioavailable metals is important for environmental assessment near mines and other industrial sources. In this study, a setup of monitoring buoys was tested to assess loads of bioavailable metals near a former Pb–Zn mine in West Greenland using transplanted seaweed, mussels and sea snails. In addition, passive DGT samplers were installed. After a 9-day deployment period, concentrations of especially Pb, Zn and Fe in the species were all markedly elevated at the monitoring sites closest to the mine. Lead concentrations in all three species and the DGT-Pb results showed a significant linear correlation. Zinc and Fe concentrations were less correlated indicating that the mechanisms for Zn and Fe accumulation in the three species are more complex. The results show that there is still a significant load of metals from the mine and that such buoys can be an adequate method to assess present loads of bioavailable metals.

Coastal power stations entrain large volumes of cooling water, requiring biocidal treatment to prevent biological fouling. Discharged effluent is both heated and contaminated with residual traces of biocide and so it is necessary to quantify the impacts of this discharge. Cooling water from Heysham 2 nuclear power station, NW England, UK, is discharged to the intertidal area, via a culvert (to minimise erosion and maximise dilution and dispersion by directing the effluent into the receiving water at all states of the tide) within which the effluent is contained at low water. The culvert and surrounding coastal area support a population of blue mussels (Mytilus edulis). Mussel health was determined along a gradient of exposure, using three physiological indices: Scope for Growth, Gonad Mantle Index and Somatic Condition Index (K Factor). The Mussels within the culvert exhibited reduced physiological index values compared to an external site. A trend was identified down the length of the culvert, representing a gradient of exposure and indicating a potential negative effect on growth and reproductive output.

Polycyclic aromatic hydrocarbon (PAH) levels were measured in sediments, bivalves and semi-permeable membrane devices (SPMDs) in the relatively pristine marine environment of Nelson Lagoon, Alaska. Most PAH levels in Nelson Lagoon were low, and similar to global background concentrations. Sampling media type can significantly influence conclusions of PAH contamination in the environment. Concentration of a broad size range of PAHs was observed in the tissues of blue mussels (Mytilus edulis). SPMDs collected some two- to three-ring PAHs from the dissolved water phase, while sediments collected five- to six-ring PAHs that were likely adsorbed onto particulate matter. Benzo(a)pyrene, a potent carcinogen, was found in mussels at levels similar to more industrialized harbors in Alaska.

Marine ecosystems are typically subjected to a variety of stressors containing complex xenobiotics mixtures. This study aims to evaluate the responses of molecular and biochemical biomarkers in the mussel Mytilus edulis providing data for environmental monitoring programs development in Southern Brazil. Mussels were collected at a polluted site, near Patos Lagoon outfall, and at a control site. Gills, muscle and mantle samples were used for biomarker determinations. Mussels collected at the polluted site significantly increased superoxide dismutase (SOD) and glutathione S-transferase (GST) activities and decreased catalase (CAT) activity. Moreover, an increase in sod1, gstπ and hsp70 mRNA expression was observed. Overall, biochemical and molecular biomarkers responses were observed, but these responses varied depending on the analyzed tissue. These results indicate possible contaminants effects on organisms and the need for effective environmental monitoring programs in this ecosystem.

Mussels (Mytilus edulis) were continuously exposed to dispersed crude oil (0.015–0.25mg/l) for 7months covering the whole gamete development cycle. After 1month exposure to 0.25mgoil/l, the level of alkali-labile phosphates (ALP) and the volume density of atretic oocytes in female gonads were higher than those in the gonads of control females, indicating that oil affected the level of vitellogenin-like proteins and gamete development. Spawning of mussels was induced after 7months oil exposure. Parental oil exposure did not affect subsequent fertilization success in clean seawater but this was reduced in 0.25mgoil/l. Parental exposure to 0.25mgoil/l caused both slow development and a higher percentage of abnormalities in D-shell larvae 2days post-fertilization; reduced growth 7days post-fertilization. These effects were greatly enhanced when larval stages were maintained at 0.25mgoil/l. Similar studies are warranted for risk assessment prognosis.

The biological impact of a treated produced water (PW) was investigated under controlled laboratory conditions in the blue mussel, Mytilus edulis. Mussel health status was assessed using an integrated biomarker approach in combination with chemical analysis of both water (with SPMDs), and mussel tissues. Acyl-CoA oxidase activity, neutral lipid accumulation, catalase activity, micronuclei formation, lysosomal membrane stability in digestive cells and haemocytes, cell-type composition in digestive gland epithelium, and the integrity of the digestive gland tissue were measured after 5week exposure to 0%, 0.01%, 0.1%, 0.5% and 1% PW. The suite of biomarkers employed were sensitive to treated PW exposure with significant sublethal responses found at 0.01–0.5% PW, even though individual chemical compounds of PW were at extremely low concentrations in both water and mussel tissues. The study highlights the benefits of an integrated biomarker approach for determining the potential effects of exposure to complex mixtures at low concentrations. Biomarkers were integrated in the Integrative Biological Response (IBR/n) index.

Since the early 1960s, the application of aluminum alloy sacrificial anodes to mitigate marine corrosion has been well known. The aim of this work was to study aluminum bioconcentration in Mytilus edulis by an in vitro test performed in two tanks: the first containing non-contaminated water (NCW) and the second containing aluminum-contaminated water (CW) (530μgL⁻¹) released by sacrificial anode. The mussels were collected and examined over a period of 8weeks. A comparison between the aluminum concentrations in the digestive glands of mussels from the CW and NCW tanks shows that the highest value (1700mg/kgd.w.) was found in the CW mussels collected after 13days. In NCW, the mean aluminum concentration in digestive glands during the test was 281mg/kgd.w. The rapid concentration decrease in digestive glands is probably due to the inhibition of filtering activity due to valve closure at the high concentration as well as the induction of the detoxification response.

Concentration of ⁹⁹Tc has been measured in fucoids and molluscs, sampled in a sheltered intertidal at the southwest coast of Norway from February to November 2006. The concentrations of ⁹⁹Tc in molluscs differed significantly between species. The filtering bivalve Mytilus edulis had the lowest concentrations with averages of 2.3–5.9Bqkg⁻¹d.w., while the herbivorous gastropods Littorinalittorina, Littorina obtusata and Patella vulgata had higher concentrations. P. vulgata and L. obtusata had the highest concentrations, 40–47 and 26–30Bqkg⁻¹d.w., respectively. L. obtusata has a specialized habit of living, and prefers to feed on fucoids. P. vulgata can graze extensively on the fucoid Ascophyllum nodosum when available. Fucoids are known to have very high uptake of ⁹⁹Tc, and this was also found in the present study. The high ⁹⁹Tc-concentrations of L. obtusata and P. vulgata are most likely due to their habit of feeding on fucoids.