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Brest harbor (Bay of Brest, Brittany, France) has a severe past of anthropogenic chemical contamination, but inputs tended to decrease, indicating a reassessment of its ecotoxicological status should be carried out. Here, native and caged mussels (Mytilus spp.) were used in combination to evaluate biological effects of chronic chemical contamination in Brest harbor. Polycyclic aromatic hydrocarbon (PAH) contamination was measured in mussel tissues as a proxy of harbor and urban pollution. Biochemical biomarkers of xenobiotic biotransformation, antioxidant defenses, generation of reducing equivalents, energy metabolism and oxidative damage were studied in both gills and digestive glands of native and caged mussels. In particular, activities of glutathione-S-transferase (GST), superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), glutathione reductase (GR), NADP-dependent isocitrate dehydrogenase (IDP), pyruvate kinase (PK) and phosphoenolpyruvate carboxykinase (PEPCK) were measured and lipid peroxidation was assessed by malondialdehyde (MDA) quantification. In addition, a condition index was calculated to assess the overall health of the mussels. Moderate PAH contamination was detected in digestive glands of both native and caged individuals from the exposed site. Modulations of biomarkers were detected in digestive glands of native harbor mussels indicating the presence of a chemical pressure. In particular, results suggested increased biotransformation (GST), antioxidant defenses (CAT), NADPH generation (IDP) and gluconeogenesis (PEPCK), which could represent a coordinated response against chemically-induced cellular stress. Lipid peroxidation assessment and condition index indicated an absence of acute stress in the same mussels suggesting metabolic changes could, at least partially, offset the negative effects of contamination. In caged mussels, only GR was found modulated compared to non-exposed mussels but significant differences in oxidative stress and energy-related biomarkers were observed compared to native harbor mussels. Overall, these results suggested mussels chronically exposed to contamination have set up metabolic adaptation, which may contribute to their survival in the moderately contaminated harbor of Brest. Whether these adaptive traits result from phenotypic plasticity or genetic adaptation needs to be further investigated., (Copyright © 2015 Elsevier B.V. All rights reserved.)

There is a growing awareness of the need to reduce the negative impact of chemical analyses on the environment and to develop new eco-friendly and sustainable analytical methods without compromising performance. In this study, we developed a "green" analytical method enabling the accurate and simultaneous routine analysis of 21 polycyclic aromatic hydrocarbons (PAHs) in reduced quantities (100mg and 1g wet weight (WW)) of marine biota samples (fish muscle, mussel and oyster tissues) using alkaline digestion combined with stir bar sorptive extraction-thermal desorption-gas chromatography-tandem mass spectrometry (SBSE-GC-MS/MS). The innovative method provides good selectivity and specificity for most compounds. In 1gWW samples, limits of quantification (LOQs) ranged from 1 to 10μg/kgWW in fish muscle and from 0.5 to 10μg/kgWW in mussel tissue. The method enables most analytes to be quantified below the restrictive limits established by the European Commission (2 and 10μg/kgWW in fish muscle and bivalve mollusc, respectively). Higher LOQs were obtained in 100mgWW samples ranging from 1 to 50μg/kgWW. Recovery and linearity were assessed for all analytes. The results were satisfactory for most compounds with recoveries ranging from 94% to 117% in 1gWW mussel samples at spike concentration of 10ng/gWW with standard deviation not exceeding 12%. However, results confirmed that the SBSE efficiency is affected by the complexity of biological matrices, especially for high molecular weight compounds in lipid-rich mussel tissue. Because of the matrix effects, matrix-matched calibrations were carried out. Validation was performed using the standard reference material 1974c with recovery ranging from 71% to 119% except for naphthalene, anthracene and benzo(e)pyrene that were therefore not validated. Overall, the developed method meets analytical validation criteria for most compounds. Thanks to the combination of alkaline digestion and SBSE, which greatly simplifies sample treatment and limits solvent use to ethanol, the developed method followed most green analytical chemistry principles., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The effects of Polycyclic Aromatic Hydrocarbons (PAHs) resulting from a water soluble fraction (WSF) of an Arabian crude oil were tested in vivo on the bioconcentration in muscles and on immune parameters in sea bass, Dicentrarchus labrax. After 15 days of acclimation, fish were acutely exposed (48 h) to the WSF of 25 g of oil, and then returned to clean sea water for a 15 day recovery period. PAH concentration in the WSF at the beginning of the exposure was estimated to 773±187 ng L⁻¹ similar to that observed in the marine environment after an oil spill. The WSF in the experimental system was composed by lightest PAH compounds and did not remain constant during the two days of exposure. Just after exposure to the WSF, a total mean concentration of 148±46 μg kg⁻¹ of PAHs was found in contaminated fish muscle, composed of parent and alkylated naphthalene compounds (86.5%), benzo[a]pyrene (10.1%) and benzo[b+k]fluoranthene (3.4%). In addition, a decrease of leucocytes counts due to a lymphopenia and granulopenia and an increase of the haemolytic activity of the alternative pathway (ACH₅₀) were noted. After a 15 day recovery period, haematocrit was decreased whereas effects on the blood granulocytes of fish seemed to be reversible, contrary to the specific immune system and quality of flesh. In fact, contaminated fish had still less lymphocyte cells compared to controls fish and their flesh were still contaminated by naphthalene and benzo[a]pyrene creating a risk for human consumers., (Crown Copyright © 2011. Published by Elsevier Inc. All rights reserved.)

Mussels (Mytilus edulis L.) were exposed to crude oil during a field experiment to evaluate two bioremediation strategies (nutrient addition and nutrient addition with tilling). The mussels were placed in 4 mesocosms: Control, Oil, Oil + Nutrients, and Oil + Nutrients + Tilled. Tilling appeared to be clearly detrimental to mussel growth. Additionally, this field experiment demonstrated that at temperatures below 5°C, growth was reduced to rates undetectable by the laser diffraction method. The data on mussel shell length show that this technique does offer very sensitive and useful comparative measurements of physiological function. Measurement of shell growth has the advantage over other techniques in that it is non-invasive and non-destructive and thus may be used continuously without disturbing critical physiological and biochemical functions; however, bivalve physiology is strongly linked to environmental conditions, so it is important to include such measures (i.e. seawater temperature and turbidity) in the design of the biomonitoring program. Elevated polycyclic aromatic hydrocarbon (PAH) levels reflected bioaccumulation in mussels from all the oiled mesocosms. This correlated with reduction in growth rate. Maximum reduction in growth was observed in mussels from the tilled mesocosm which contained the lowest phenanthrene and dibenzothiophene concentrations. The tilling caused an increase in suspended solids which inhibited filter feeding activity, and resulted in suppressed growth and slower intake of PAH-laden sediment. [ABSTRACT FROM AUTHOR]