Pascal Mora

One-year monitoring survey of organic compounds (PAHs, PCBs, TBT), heavy metals and biomarkers in blue mussels from the Arcachon Bay, France

Marine mussels Mytilus sp. were transplanted on a monthly basis in cages over one year to oyster farms and harbours in the Arcachon Bay (France) in order to assess the water quality of the bay. Contaminant levels (organotin compounds, trace metals, PCBs and PAHs) were measured in tissues of transplanted mussels and mussels from a reference station, along with physiological parameters of the mussels (condition indexes, lipid content and dry weight). Four biomarkers (AChE: acetylcholinesterase activity, GST: gluthathione S-transferase activity, CAT: catalase activity and TBARS: thiobarbituric acid-reactive substance content) were also monitored. The remote stations monitored (oyster parks) exhibited no accumulation pattern of pollutants. Their respective concentrations therefore constitute a background level of the contamination in the bay ([TBT]= 30 ng Sn g(-1) dw, [SigmaHAPs]= 100 ng g(-1) dw, [SigmaPCBs]= 35 ng g(-1) dw). The elevated chemical contamination of the largest harbour of the bay, the Arcachon harbour, can be interpreted in terms of persistence of organotin compounds ([SigmaOTs]= 1500-2000 ng Sn g(-1) dw) and PAHs ([SigmaHAPs]= 4500-5000 ng g(-1) dw) in sediments and, to a lesser extent, of direct inputs of copper ([Cu]= 20 microg g(-1) dw in harbours versus 7 in oyster parks) and petrogenic PAHs ([methylphenanthrenes]= 1600 ng g(-1) dw in the dockyard versus 170 at the gas stations), related to the use of copper-based antifouling paints and to dockyard activity, respectively. However, the Arcachon Bay presents a low contamination level by PCBs and metals, including harbour stations. Furthermore, higher levels of other PAHs (particularly alkyl PAHs such as methylphenanthrenes/1600 ng g(-1) dw) not included in the 16 PAHs from the EPA priority list (usually studied in biomonitoring programmes/1500 ng g(-1) dw) in the Arcachon harbour underline the need to integrate these compounds in biomonitoring of highly PAH-polluted areas such as harbours in order to avoid misinterpretation of the biological responses observed. Biomarker responses were not able to discriminate the different chemical contamination levels recorded in the Arcachon Bay and rather reflected changes in environmental factors. Furthermore, the strong intraspecies variability of biological responses could be due to genetic differences of mussels from the Arcachon Bay. It is the first time that such an integrated monitoring is performed in the Arcachon Bay, also taking into account seasonal variations of chemical contents and biomarkers levels in mussel tissues.

Cholinesterases from the marine mussels Mytilus galloprovincialis Lmk. and M. edulis L. and from the freshwater bivalve Corbicula fluminea Müller

In order to improve the molecular basis for the use of bivalve cholinesterases as a reliable biomarker for aquatic pollution, the polymorphism and characterization of these enzymes in Mytilus edulis, Mytilus galloprovincialis and Corbicula fluminea were investigated. All results are consistent with the presence of only one pharmacological form of cholinesterase in each species. The molecular masses were 180 kDa for the two marine mussels and 240 kDa for C. fluminea. The cholinesterases are anchored to the membrane by a glycosyl inositol phosphate like the Ga form (type I) described in vertebrates. Surprisingly, these cholinesterases were poorly inhibited by organophosphorous compounds compared to enzymes from other sources. This suggests that these bivalves could be used as a biomarker for acute rather than chronic contaminations by anticholinesterase insecticides.

Scoring approach based on fish biomarkers applied to French river monitoring

The aim was to apply a multimarker scoring approach as complementary to freshwater monitoring programmes carried out by the Water Agency Adour–Garonne. Fish (chub, barbel and trout) were collected in 11 sites in rivers in south-west France. Five biomarkers of response were measured either in muscle or brain for acetylcholinesterase (AChE) and in liver for glutathione S-transferase, catalase and 7-ethoxyresorufine O-deethylase. As a result of multivariate analysis, sites were clearly discriminated mainly by 7-ethoxyresorufine O-deethylase and acetylcholinesterase activities. According to the scoring approach, a multimarker pollution index was calculated for each sampling site as the sum of the response index of the five measured biomarkers (pollution index). Sorting was established by ranging the sites from lightly to highly contaminated locations.

Microcosm tributyltin bioaccumulation and multibiomarker assessment in the blue mussel Mytilus edulis

Blue mussels, Mytilus edulis, were exposed to two different concentrations of tributyltin (TBT) in seawater, 1,000 ng Sn/L (C1 experiment) and 10 ng Sn/L (C2 experiment), for 4 d, in order to evaluate the bioaccumulation of TBT by mussels Mytilus edulis in microcosms and to test the ability of a multimarkers analysis to determine the effects of TBT on the biochemical parameters in mussels. Tissue burdens of Mytilus edulis were 204 +/- 7 and 2,120 +/- 4 ng Sn/g TBT after the 4-d tests for the C2 and C1 experiments, respectively. Analyses of dissected organs and/or tissues demonstrated that TBT accumulated to the greatest extent in gills in the C1 experiment and in the digestive gland in the C2 experiment. Bioconcentration factors (BCFs) were 12,100 +/- 300 and 2,000 +/- 10 for mussels exposed in the C2 and C1 experiments, respectively. The four biomarkers used in this work were acetylcholinesterase (AChE), glutathione S-transferase (GST), catalase (CAT) activities, and thiobarbituric acid-reactive substances (TBARS) contents. No significant changes were observed in the measured enzyme activities or in TBARS concentration after the 4-d TBT exposure.

BIOCHEMICAL MARKERS IN MUSSEL, MYTILUS SP., AND POLLUTION MONITORING IN EUROPEAN COASTS : DATA ANALYSIS

Abstract Biomarker measurements and chemical contaminant data determined in marine mussels and collected during BIOMAR cruises (Baltic Sea, Mediterranean Sea, Atlantic Ocean) have been compiled and statistically treated to get a Multimarker Pollution Index (MPI). The discreminant analysis show a significant difference between the studied sites. The MPI allows the ranking of the sites according to a pollution classification scale from 1 to 5.

Cytochrome P450 Dependent Activities in Mussel and Fish from Coastal Marine Environment: Field Studies on the French Coast of the Mediterranean Sea

Abstract Hepatic cytochrome P450 monooxygenase activities including Benzo(a)pyrene hydroxylase (BPH), biomarker of exposure to polycyclic hydrocarbons (PAH) and other organic contaminants like polychlorobiphenyls (PCB) was measured in the microsomal fraction from the fish, Serranus cabrilla (sea comber) liver, and the mussel, Mytilus galloprovincialis, digestive gland. Additionally, ethoxyresorufin-O-deethylase (EROD) activity measurements were made on the same fish samples. The animals were collected from multiple sites on the French Mediterranean coast, exhibiting various degrees of sediment contamination by urban/industrial wastes quantified in term of PAH and PCB sediment content. Mussel BPH, fish BPH and to a lower extent fish EROD activities were tentatively correlated to sediment PAH/PCB content. The presence of low concentration (20 μM) of α-naphthoflavone (ANF) in the assay mixture increased hepatic BPH activity of sea comber. Statistical correlation of hepatic BPH with PAH level in sediment was greater with the presence of ANF. This work demonstrates the potential of mussel to be used in biomonitoring programmes for coastal pollution survey.

In Vitro Detection and Quantification of Testosterone Metabolites in Aquatic Organisms

Abstract High‐performance liquid chromatography (HPLC) was used to evaluate testosterone metabolism in aquatic animals generally used as sentinel species (i.e., fish and molluscs). The profiles of testosterone metabolites resulting from incubation of liver microsomes from trout Oncorhynchus mykiss, digestive gland S9 from clams, Corbicula fluminea and mussels Mytilus galloprovincialis were compared. Main metabolites 6β‐hydroxytestosterone, 16α‐hydroxytestosterone, 11β‐hydroxytestosterone, 2α‐hydroxytestosterone, 2β‐hydroxytestosterone and androstenedione were detected and quantified in rat, fish, and clam, whereas only 16α‐hydroxytestosterone and androstenedione metabolites were detected in mussels. Testosterone metabolite profiles detected in cellular fractions were further analyzed. The protocol presented in this study may be considered as a useful tool for biomarker based pollution surveys. Supported by the European project Biological Effects of Environmental Pollution in marine coastal ecosystems: BEEP (Contract EVK3‐CT2000‐00025) is part of the EC IMPACTS cluster. We thank Dr Kramer, IECB, Pessac, for critically reading the manuscript and correcting the English language.