Physiological effects of PFAS exposure in seabird chicks: A multi-species study of thyroid hormone triiodothyronine, body condition and telomere length in South Western France.

There is growing evidence that poly and perfluoroalkyl substances (PFAS) exposure leads to the disruption of thyroid hormones including thyroxine (T4) and triiodothyronine (T3), and may affect telomeres, repetitive nucleotide sequences which protect chromosome ends. Many seabird species are long-lived top predators thus exhibit high contaminant levels, and PFAS-disrupting effects on their physiology have been documented especially in relation to the endocrine system in adults. On the contrary, studies on the developmental period (i.e., chicks), during which exposure to environmental contaminants may have a greater impact on physiological traits, remain scarce to this date. We carried out a multi-species study with the aim to assess whether and to which extent chicks of four gull species (herring gull, great and lesser black-backed gull, yellow-legged gull) in South Western France are contaminated by PFAS, and to bring further evidence about their potential physiological consequences. Linear PFOS showed concentrations of concern as it was generally >10 times higher than the other PFAS, and exceeded a threshold toxicity level (calculated from previous studies in birds) in almost all sampled chicks. Nonetheless, in herring gull male chicks, total T3 levels were significantly and negatively associated with perfluorodecanoate (PFDA) and perfluorododecanoate (PFDoDA) and positively associated with perfluorotetradecanoate (PFTeDA) in female chicks. Total T3 levels were also positively associated with PFDoDA in great black backed gull male chicks and with perfluorotridecanoate (PFTrDA) in lesser black backed gull chicks. In lesser and great black-backed gulls, both females and males showed significant negative associations between several PFAS and their body condition, and a positive association between telomere length and L-PFOS in the yellow-legged gull was also found. These results corroborate previous findings and need to be further explored as they suggest that PFAS may interfere with the physiological status of chicks during the developmental period, potentially inducing long-lasting consequences.

Effects of metals and persistent organic pollutants on the fitness and health of juveniles of the endangered european sturgeon Acipenser sturio Exposed to W1ater and sediments of the garonne and dordogne rivers.

The last remaining population of European sturgeon (Acipenser sturio) lives in the Gironde-Garonne-Dordogne (France) catchment (GGD). Captive young individuals are released into the GGD hydrosystem each year, as part of a restocking programme. This study aims to assess the health status of juveniles A. sturio to current conditions in the GGD hydrosystem, to evaluate their capacity to survive and grow in a moderately anthropized ecosystems. 3-month-old farmed sturgeons were exposed for one month in experimental conditions that mimic the environmental conditions in the Garonne and Dordogne rivers, followed by five months of depuration. After one month of exposure, fish exposed to Dordogne and Garonne waters bioaccumulated higher levels of metals and persistent organic pollutants, displayed a reduced hepato-somatic index, and had depleted levels of lipids and glycogen content in their liver, when compared with the Reference group. However, metabolic and swimming performance, as well as the costs of swimming were not impaired. After the 5 months depuration, a significant decrease of K was observed for all exposure conditions. HSI also decreased with time. The overall health status and adaptive capacity of juvenile A. sturio appeared to be maintained over the experimental 6 months' period. Juveniles of A. sturio seem to have the adaptive capacity to survive and grow in the GGD hydrosystem, after being released as part of a restocking programme.

Development in the European flounder (Platichthys flesus) of a q-PCR assay for the measurement of telomere length, a potential biomarker of pollutant effects for biomonitoring studies.

Telomeres protect the coding sequence of chromosome ends and Telomere Length (TL) has been proposed as a biomarker of cellular aging, cumulative stress exposure and life-span in humans. With the aim to propose new biomarkers, a q-PCR protocol was adapted for the measurement of TL in the European flounder Platichthys flesus. The protocol was then applied in 2-year-old flounders from the Seine Estuary. The absolute TL in the flounder is 54 ± 13 kbp per genome (mean ± standard error). Considering relative or absolute TL, no correlation was observed with DNA damage and any of the measured contaminant concentrations (trace elements, metabolites of polycyclic aromatic hydrocarbons, polychlorobiphenyls, organochlorinated pesticides, polybrominated diphenyl ethers, perfluoroalkyl substances). Because sampling was limited, further investigations are required to state a possible impact of chemical pollution on flatfish telomeres. This is motivated by correlations observed with organochlorinated compounds when decreasing statistical significance (p ≤ 0.10).

High levels of fluoroalkyl substances and potential disruption of thyroid hormones in three gull species from South Western France.

Per- and poly-fluoroalkyl substances (PFAS) raised increasing concerns over the past years due to their persistence and global distribution. Understanding their occurrence in the environment and their disruptive effect on the physiology of humans and wildlife remains a major challenge in ecotoxicological studies. Here, we investigate the occurrence of several carboxylic and sulfonic PFAS in 105 individuals of three seabird species (27 great black-backed gull Larus marinus; 44 lesser black-backed gull Larus fuscus graellsii; and 34 European herring gull Larus argentatus) from South western France. We further estimated the relationship between plasma concentrations of PFAS and i) the body condition of the birds and ii) plasma concentrations of thyroid hormone triiodothyronine (TT3). We found that great and lesser black-backed gulls from South Western France are exposed to PFAS levels comparable to highly contaminated species from other geographical areas, although major emission sources (i.e. related to industrial activities) are absent in the region. We additionally found that PFAS are negatively associated with the body condition of the birds in two of the studied species, and that these results are sex-dependent. Finally, we found positive associations between exposure to PFAS and TT3 in the great black-backed gull, suggesting a potential disrupting mechanism of PFAS exposure. Although only three years of data have been collected, we investigated PFAS trend over the study period, and found that great black-backed gulls document an increasing trend of plasma PFAS concentration from 2016 to 2018. Because PFAS might have detrimental effects on birds, French seabird populations should be monitored since an increase of PFAS exposure may impact on population viability both in the short- and long-term.

Experimental Study of the Formation of Organosulfates from α-Pinene Oxidation. 2. Time Evolution and Effect of Particle Acidity.

The present work is an extensive laboratory study of organosulfate (OS) formation from the reaction of α-pinene oxidation products or proxies with acidified ammonium sulfate aerosols in three different acidity conditions ((NH4)2SO4 0.06 M; (NH4)2SO4/H2SO4 0.06 M/0.005 M; (NH4)2SO4/H2SO4 0.03 M/0.05 M). The kinetics of the reactions of α-pinene, α-pinene oxide, isopinocampheol, pinanediol, and myrtenal with ammonium sulfate particles were studied using a quasi-static reactor. The reaction of α-pinene oxide with the highly acidic ammonium sulfate particles was determined to be 7, 10, 21, and 24 times faster than for isopinocampheol, α-pinene, pinanedial, and myrtenal, respectively, for an OS precursor concentration of 1 ppm and after 1 h reaction time. The effective rate coefficients for OS formation from α-pinene oxide were determined to be 2 orders of magnitude higher in highly acidic conditions than for the two other acidity conditions. For α-pinene oxide reactions with highly acidic ammonium sulfate particles, OS formation was observed to increase linearly with (i) the time of reaction up to 400 min (r2 > 0.95) and (ii) α-pinene oxide gas-phase concentration. However, OS formation from α-pinene oxide reactions with slightly acidic or pure ammonium sulfate particles was limited, with a plateau ([OS]max = 0.62 ± 0.03 µg) reached after around 15-20 min. Organosulfate dimers (m/z 401 and m/z 481) were detected not only with highly acidic particles but also with slightly acidic and pure ammonium sulfate particles, indicating that oligomerization processes do not require strong acidity conditions. Dehydration products of organosulfates (m/z 231 and m/z 383) were observed only under highly acidic conditions, indicating the key role of H2SO4 on the dehydration of organosulfates and the formation of olefins in the atmosphere. Finally, this kinetic study was completed with simulation chamber experiments in which the mass concentration of organosulfates was shown to depend on the available sulfate amount present in the particle phase (r2 = 0.96). In conclusion, this relative comparison between five organosulfate precursors shows that epoxide was the most efficient reactant to form organosulfates via heterogeneous gas-particle reactions and illustrates how gas-particle reactions may play an important role in OS formation and hence in the atmospheric fate of organic carbon. The kinetic data presented in this work provide strong support to organosulfate formation mechanisms proposed in part 1 ( J. Phys. Chem. A 2016 , 120 , 7909 - 7923 ).

Combined spatial and retrospective analysis of fluoroalkyl chemicals in fluvial sediments reveal changes in levels and patterns over the last 40 years.

Bed sediments and a dated sediment core were collected upstream and downstream from the city of Lyon (France) to assess the spatial and temporal trends of contamination by per- and polyfluoroalkyl substances (PFASs) in this section of the Rhône River. Upstream from Lyon, concentrations of total PFASs (ΣPFASs) in sediments are low (between 0.19 and 2.6 ng g-1 dry weight - dw), being characterized by a high proportion of perfluorooctane sulfonate (PFOS). Downstream from Lyon, and also from a fluoropolymer manufacturing plant, ΣPFASs concentrations reach 48.7 ng g-1 dw. A gradual decrease of concentrations is reported at the coring site further downstream (38 km). Based on a dated sediment core, the temporal evolution of PFASs is reconstructed from 1984 to 2013. Prior to 1987, ΣPFASs concentrations were low (≤2 ng g-1 dw), increasing to a maximum of 51 ng g-1 dw in the 1990s and then decreasing from 2002 to the present day (∼10 ng g-1 dw). In terms of the PFAS pattern, the proportion of perfluoroalkyl sulfonic acids (PFSAs) has remained stable since the 1980s (∼10%), whereas large variations are reported for carboxylic acids (PFCAs). Long chain- (C > 8) PFCAs characterized by an even number of perfluorinated carbons represent about 74% of the total PFAS load until 2005. However, from 2005 to 2013, the relative contribution of long chain- (C > 8) PFCAs with an odd number of perfluorinated carbons reaches 80%. Such changes in the PFAS pattern likely highlight a major shift in the industrial production process. This spatial and retrospective study provides valuable insights into the long-term contamination patterns of PFAS chemicals in river basins impacted by both urban and industrial activities.

Assessment of the effects of discontinuous sources of contamination through biomarker analyses on caged mussels.

The present study analysed potential adverse effects of discontinuous sources of contamination, namely the discharge of a combined sewer overflow (CSO) and of runoff in an urban area, the Bay of Santander (North Iberian Peninsula). Water samples and caged mussels were used to analyse concentrations of contaminants and biological responses. Mussels (Mytilus galloprovincialis) were transplanted to a marina receiving runoff from a petrol station and to a CSO discharge site. Samples were collected in synchrony with heavy rains along 62days. Lysosomal membrane stability (LMS) and acyl-CoA oxidase (AOX) activity were measured as core biomarkers and were analysed at all sampling times. Histopathology of digestive gland and gonads, transcription levels of vitellogenin gene, volume density of black silver deposits and micronuclei formation were measured at initial and final stages of the transplant. Chemical analyses of metals, polycyclic aromatic hydrocarbons (PAHs) and endocrine disruptors were performed in water samples and mussel flesh. Mussels accumulated low concentrations of contaminants, which is in accordance with results obtained from exposure biomarkers. AOX activity decreased in all transplanted mussels after the first heavy rain, but this change seems to be related to the seasonal pattern of the enzyme activity. Mussels located close to the CSO discharge site showed a reduction in LMS after the first rain event, when compared to mussels before the transplant and to mussels from the reference location. However, this was attributable to natural environmental changes rather than to pollution. Values of the rest of analysed biomarkers were below threshold values reported for the study area.

Demographic, endocrine and behavioral responses to mirex in the South polar skua.

Population consequences of chronic exposure to multiple pollutants at low environmental doses remain speculative, because of the lack of appropriate long-term monitoring surveys. This study integrates proximate and ultimate aspects of persistent organic pollutants (POP) burden in free-living vertebrates, by coupling hormonal and behavioral endpoints, life-history traits, and population dynamics. Blood samples (N=70) were collected in South polar skuas during two breeding periods, in 2003 and 2005, and individuals were annually monitored until 2011. Multi-state mark recapture models were used to test the effects of POP levels on demographic traits. Survival rate and long-term breeding probability were not related to individual POP levels, whereas long-term breeding success significantly decreased with increasing blood levels of mirex, an organochlorine insecticide. At the proximate level, corticosterone (stress hormone) and prolactin (parental care hormone) levels were not linked to individual POP burden. Nest defense in 2005 was significantly less intensive in chick-rearing skuas bearing higher mirex levels, suggesting reproductive behavioral impairment. Matrix population models were then built to project the rate of population decline according to increasing mirex burden. Although mirex levels were 2.8 times higher in 2003 than in 2005, the population-level effect of mirex was only detected in 2005, the year of higher corticosterone levels. The combination of endocrine traits with demographic analysis thereby enables to provide new support of synergistic interactions between pollutants and stress levels on long-term breeding outputs and population dynamics.

PAH metabolites in fish bile: From the Seine estuary to Iceland.

Polycyclic aromatic hydrocarbons (PAH) are environmental contaminants that pose significant risk to health of fish. The International Workshop on Integrated Assessment of Contaminant Impacts on the North Sea (ICON) provided the framework to investigate biomarker responses as well as contaminant concentrations side by side in marine ecosystems. Concentrations of the main PAH metabolites 1-hydroxypyrene, 1-hydroxyphenanthren and 3-hydroxybenzo(a)pyrene were determined in bile by HPLC with fluorescence detection. Fish species under investigation were dab (Limanda limanda), flounder (Platichthys flesus) and haddock (Melanogrammus aeglefinus). A contamination gradient was demonstrated from the low contaminated waters of Iceland and off-shore regions of the North Sea towards higher concentrations in coastal areas. Concentrations of PAH metabolites differed primarily according to sampling region and secondarily to species.

Development of a multi-residue method for scrutinizing psychotropic compounds in natural waters.

The present work describes a multi-residue SPE-UPLC-MS/MS method aiming at the characterization of 68 compounds in natural waters, including parent compounds as well as their major metabolites and glucuronide conjugates. Development was conducted toward the quantitative determination of a broad range of analytes belonging to different class of psychotropic drugs such as benzodiazepines, antidepressants, stimulants, opiates and opioids, anticonvulsants, anti-dementia drugs, analgesic and anti-inflammatory drugs (as anthropic indicators) in the low ngL-1 range of concentration. Satisfactory extraction recoveries >70% were obtained for the majority of analytes (49 out of 68) allowing low limits of quantification. LOQ ranged between 0.1 and 17.8ngL-1 and were lower than 5ngL-1 for 94% of investigated analytes. Furthermore, addition of 25 isotopic labeled standards allowed to ensure reliability of the optimized method. Quantification errors were typically below 15% with relative standard variations <10% in intermediate precision conditions. Finally, the developed method was implemented in natural waters; sampling campaigns were conducted in the Seine River as a demonstration of the applicability and adequation of the method for its purpose. As a result, 48 out of 68 analytes were identified or quantified; some of them like memantine, rivastigmine, zolpidem 4-phenyl-carboxylic acid, zolpidem 6-carboxylic acid for one of the first time in surface waters. Among investigated psychotropic compounds and metabolites, tramadol, codeine, oxazepam, venlafaxine, O-desmethylvenlafaxine, gabapentin, carbamazepine and 10,11-dihydro-10,11-dihydroxycarbamazepine were found to be the most abundant.

Experimental Study of the Formation of Organosulfates from α-Pinene Oxidation. Part I: Product Identification, Formation Mechanisms and Effect of Relative Humidity.

In the present study, quasi-static reactor and atmospheric simulation chamber experiments were performed to investigate the formation of α-pinene-derived organosulfates. Organosulfates (R-OSO3H) were examined for the reactions between acidified ammonium sulfate particles exposed to an individual gaseous volatile organic compound, such as α-pinene and oxidized products (α-pinene oxide, isopinocampheol, pinanediol and myrtenal). Molecular structures were elucidated by liquid chromatography interfaced to high-resolution quadrupole time-of-flight mass spectrometry equipped with electrospray ionization (LC/ESI-HR-QTOFMS). New organosulfate products were detected and identified for the first time in the present study. Reaction with α-pinene oxide was found to be a favored pathway for organosulfate formation (C10H18O5S) and to yield organosulfate dimers (C20H34O6S and C20H34O9S2) and trimers (C30H50O10S2) under dry conditions (RH < 1%) and high particle acidity and precursor concentrations (1 ppm). The role of relative humidity on organosulfate formation yields and product distribution was specifically examined. Organosulfate concentrations were found to decrease with increasing relative humidity. Mechanistic pathways for organosulfate formation from the reactions between α-pinene, α-pinene oxide, isopinocampheol, or pinanediol with acidified ammonium sulfate particles are proposed.

RAD sequencing reveals within-generation polygenic selection in response to anthropogenic organic and metal contamination in North Atlantic Eels.

Measuring the effects of selection on the genome imposed by human-altered environment is currently a major goal in ecological genomics. Given the polygenic basis of most phenotypic traits, quantitative genetic theory predicts that selection is expected to cause subtle allelic changes among covarying loci rather than pronounced changes at few loci of large effects. The goal of this study was to test for the occurrence of polygenic selection in both North Atlantic eels (European Eel, Anguilla anguilla and American Eel, A. rostrata), using a method that searches for covariation among loci that would discriminate eels from 'control' vs. 'polluted' environments and be associated with specific contaminants acting as putative selective agents. RAD-seq libraries resulted in 23 659 and 14 755 filtered loci for the European and American Eels, respectively. A total of 142 and 141 covarying markers discriminating European and American Eels from 'control' vs. 'polluted' sampling localities were obtained using the Random Forest algorithm. Distance-based redundancy analyses (db-RDAs) were used to assess the relationships between these covarying markers and concentration of 34 contaminants measured for each individual eel. PCB153, 4'4'DDE and selenium were associated with covarying markers for both species, thus pointing to these contaminants as major selective agents in contaminated sites. Gene enrichment analyses suggested that sterol regulation plays an important role in the differential survival of eels in 'polluted' environment. This study illustrates the power of combining methods for detecting signals of polygenic selection and for associating variation of markers with putative selective agents in studies aiming at documenting the dynamics of selection at the genomic level and particularly so in human-altered environments.

Validation and uncertainties evaluation of an isotope dilution-SPE-LC-MS/MS for the quantification of drug residues in surface waters.

The present work describes the development and validation of a reference method conducted at the French National Institute of Metrology (LNE) for the quantitative determination of psychoactive compounds in the dissolved fraction of surface waters. More specifically an isotope dilution-SPE-LC-MS/MS based method has been implemented for the characterization of a broad range of analytes belonging to different classes of psychotropic drugs such as benzodiazepines, antidepressants, stimulants, opiates and opioids, anticonvulsants, anti-dementia drugs, analgesics as well as the anti-inflammatory drug diclofenac in the low ng L(-1) range of concentration. Full validation of the method was performed following procedures described by the French standard NF T90-210. Limits of quantification between 0.14 and 3.54 ng L(-1) were obtained. Method recoveries from 71 to 123% were observed with standard deviation below 10% in intermediate precision conditions. Accuracy was determined for every compound: measurement errors were between -4 and +1% and standard deviations in intermediate precision conditions were included within a 1-9% interval. Finally, measurement uncertainties were evaluated following the Guide to the expression of uncertainty in measurement (GUM). Expanded uncertainties (k=2) ranged from 2% for carbamazepine, EDDP (2-ethylidene-1,5-dimethyl-3,3-diphenylpyrrolidine) and venlafaxine to 17% for diazepam. The validated method was implemented to Seine river surface waters demonstrating its fitness for purpose. All compounds were detected and 22 out of 25 analytes were quantified. More specifically, measured concentration ranged from 0.39 ng L(-1) for MDMA (3,4-methylene-dioxy-N-methylamphetamine) to 182 ng L(-1) for gabapentine.

Proteomic changes in Corbicula fluminea exposed to wastewater from a psychiatric hospital.

The increase use of pharmaceutical compounds in veterinary practice and human population results in the ubiquitous presence of these compounds in aquatic ecosystems. Because pharmaceuticals are highly bioactive, there is concern about their toxicological effects in aquatic organisms. Therefore, the aim of this study was to assess the effects of an effluent from a psychiatric hospital (containing a complex mixture of 25 pharmaceutical compounds from eleven therapeutic classes) on the freshwater clam Corbicula fluminea using a proteomic approach. The exposure of C. fluminea to this complex effluent containing anxiolytics, analgesics, lipid regulators, beta blockers, antidepressants, antiepileptics, antihistamines, antihypertensives, antiplatelets and antiarrhythmics induced protein changes after 1 day of exposure in clam gills and digestive gland more evident in the digestive gland. These changes included increase in the abundance of proteins associated with structural (actin and tubulin), cellular functions (calreticulin, proliferating cell nuclear antigen (PCNA), T complex protein 1 (TCP1)) and metabolism (aldehyde dehydrogenase (ALDH), alcohol dehydrogenase, 6 phosphogluconate dehydrogenase). Results from this study indicate that calreticulin, PCNA, ALDH and alcohol dehydrogenase in the digestive gland and T complex protein 1 (TCP1)) and 6 phosphogluconate dehydrogenase in the gills represent useful biomarkers for the ecotoxicological characterization of psychiatric hospital effluents in this species.

Persistent organic pollutants in a marine bivalve on the Marennes-Oléron Bay and the Gironde Estuary (French Atlantic Coast) - part 2: potential biological effects.

Contaminant effects on defence responses of ecologically and economically important organisms, such as the Pacific oyster Crassostrea gigas, are likely to influence their ability to resist infectious diseases, particularly at the young stages. The aim of this study was to explore the potential relationships between organic contaminants accumulated in the soft tissues of juvenile oysters, defence responses and physiological condition. Oysters were transplanted during summer and winter periods in different sites in the Marennes-Oléron Bay, the first area of oyster production in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe. Amongst the battery of biochemical and physiological biomarkers applied in the present work [superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), malondyaldehyde (MDA), catecholase, laccase and lysozyme in gills, digestive glands, mantle and haemolymph, glycogen, proteins and lipids in the digestive gland and the condition index at the whole-organism level], MDA and lysozyme in the digestive gland and SOD, GPx and laccase in plasma contributed in order to significantly discriminate the sites in which oysters bioaccumulated different levels of heavy polycyclic aromatic hydrocarbons (HPAHs), polychlorobiphenyls (PCBs), polybromodiphenylethers (PBDEs), dichlorodiphenyltrichloroethanes (DDTs) and lindane. These results strengthen the hypothesis that it is possible to differentiate sites depending on their contamination levels and biological effects by carrying out studies with transplanted juvenile oysters. In addition, correlations were found between antioxidant and immune-defence responses, and PAH and DDT body burdens in the first area of oyster production in France (the Marennes-Oléron Bay) and where considerable oyster mortalities have been reported. This result suggests that the presence of organic chemical contaminants in the Marennes-Oléron Bay may influence defence responses in juveniles of C. gigas, and, therefore, could influence their ability to resist infectious diseases.

Lab-scale experimental strategy for determining micropollutant partition coefficient and biodegradation constants in activated sludge.

The nitrifying/denitrifying activated sludge process removes several micropollutants from wastewater by sorption onto sludge and/or biodegradation. The objective of this paper is to propose and evaluate a lab-scale experimental strategy for the determination of partition coefficient and biodegradation constant for micropollutant with an objective of modelling their removal. Four pharmaceutical compounds (ibuprofen, atenolol, diclofenac and fluoxetine) covering a wide hydrophobicity range (log Kow from 0.16 to 4.51) were chosen. Dissolved and particulate concentrations were monitored for 4 days, inside two reactors working under aerobic and anoxic conditions, and under different substrate feed conditions (biodegradable carbon and nitrogen). We determined the mechanisms responsible for the removal of the target compounds: (i) ibuprofen was biodegraded, mainly under aerobic conditions by cometabolism with biodegradable carbon, whereas anoxic conditions suppressed biodegradation; (ii) atenolol was biodegraded under both aerobic and anoxic conditions (with a higher biodegradation rate under aerobic conditions), and cometabolism with biodegradable carbon was the main mechanism; (iii) diclofenac and fluoxetine were removed by sorption only. Finally, the abilities of our strategy were evaluated by testing the suitability of the parameters for simulating effluent concentrations and removal efficiency at a full-scale plant.

Persistent organic pollutants in a marine bivalve on the Marennes-Oléron Bay and the Gironde Estuary (French Atlantic Coast) - part 1: bioaccumulation.

The aim of this study was to determine 1) the relevance of using the Pacific oyster Crassostrea gigas as a sentinel organism, at a juvenile stage, for polycyclic aromatic hydrocarbon (PAH) and persistent organic pollutant (polychlorobiphenyl, PCB, polybromodimethylether, PBDE, and organochlorine pesticide, OCP) contamination, 2) the potential levels of chemical organic contamination in the Marennes-Oléron Bay, and their potential sources and 3) the potential influence of physiological or environmental factors on contaminant body burdens in oysters. To this end, juvenile oysters purchased from an oyster hatchery were transplanted to a reference site, in Bouin, and to different transplantation sites in the Marennes-Oléron Bay, the first oyster production area in France, and in the Gironde Estuary, the biggest estuary in Occidental Europe. Transplantations were done during summer and winter. Whole oyster soft tissues from each site were analysed for PAHs, PCBs, PBDEs and OCPs. Results obtained with a transplantation period of 3months suggest that C. gigas, at the juvenile stage, is a relevant sentinel organism for short-term assessment of contamination for these contaminants. In addition, no significant effects of physiological factors on contaminant body burdens were observed. Principal component analysis revealed two distinct groups of contaminants (PAHs and OPCs, and PCBs and PBDEs) and three groups of sites: 1) the reference site, 2) Les Palles (LP) and Boyard (BOY) in winter and 3) all the other sites. The group of LP and BOY was clearly defined by the levels of PAHs and OCPs, suggesting higher levels of contamination of these chemical compounds on these sites, potentially due to local contamination sources. In addition, no relevant effects of physiological or environmental factors on contaminant body burdens were observed. Results suggest also a predominance of contaminants related to agricultural activities along the Marennes-Oléron Bay, and therefore, further studies on the presence of pesticides in this region should be considered.

Polychlorinated biphenyl exposure and corticosterone levels in seven polar seabird species.

The role of polychlorinated biphenyls (PCBs) on exposure-related endocrine effects has been poorly investigated in wild birds. This is the case for stress hormones including corticosterone (CORT). Some studies have suggested that environmental exposure to PCBs and altered CORT secretion might be associated. Here we investigated the relationships between blood PCB concentrations and circulating CORT levels in seven free-ranging polar seabird species occupying different trophic positions, and hence covering a wide range of PCB exposure. Blood ∑7PCB concentrations (range: 61-115,632 ng/g lw) were positively associated to baseline or stress-induced CORT levels in three species and negatively associated to stress-induced CORT levels in one species. Global analysis suggests that in males, baseline CORT levels generally increase with increasing blood ∑7PCB concentrations, whereas stress-induced CORT levels decrease when reaching high blood ∑7PCB concentrations. This study suggests that the nature of the PCB-CORT relationships may depend on the level of PCB exposure.

BFCOD activity in fish cell lines and zebrafish embryos and its modulation by chemical ligands of human aryl hydrocarbon and nuclear receptors.

Assessment of exposure and effect of fish to pharmaceuticals that contaminate aquatic environment is a current major issue in ecotoxicology and there is a need to develop specific biological marker to achieve this goal. Benzyloxy-4-trifluoromethylcoumarin-O-debenzyloxylase (BFCOD) enzymatic activity has been commonly used to monitor CYP3A activity in fish. In this study, we assessed the capacity of a panel of toxicologically relevant chemicals to modulate BFCOD activity in fish, by using in vitro and in vivo bioassays based on fish liver cell lines (PLHC-1, ZFL, RTL-W1) and zebrafish embryos, respectively. Basal BFCOD activity was detectable in all biological models and was differently modulated by chemicals. Ligands of human androgens, glucocorticoids, or pregnanes X receptors (i.e., dexamethasone, RU486, rifampicin, SR12813, T0901317, clotrimazole, ketoconazole, testosterone, and dihydrotestosterone) moderately increased or inhibited BFCOD activity, with some variations between the models. No common feature could be drawn by regards to their capacity to bind to these receptors, which contrasts with their known effect on mammalian CYP3A. In contrast, dioxins and polycyclic aromatic hydrocarbons (PAHs) strongly induced BFCOD activity (up to 30-fold) in a time- and concentration-dependent manner, both in vitro in all cell lines and in vivo in zebrafish embryos. These effects were AhR dependent as indicated by suppression of induced BFCOD by the AhR pathway inhibitors 8-methoxypsoralen and α-naphthoflavone. Altogether our result further question the relevance of using liver BFCOD activity as a biomarker of fish exposure to CYP3A-active compounds such as pharmaceuticals.

Corticosterone, prolactin and egg neglect behavior in relation to mercury and legacy POPs in a long-lived Antarctic bird.

Seabirds often have high loads of contaminants. These contaminants have endocrine disrupting properties but their relationships with some endocrine mechanisms are still poorly investigated in free-living organisms. This is the case for the stress response which shifts energy investment away from reproduction and redirects it towards survival. In birds, this stress response is achieved through a release of corticosterone and is also accompanied by a decrease in circulating prolactin, an anterior pituitary hormone widely involved in regulating parental cares. We measured blood concentrations of some legacy persistent organic pollutants (POPs) and mercury (Hg) and examined their relationships with the corticosterone and prolactin responses of known-age (9-46 years old) incubating snow petrels (Pagodroma nivea) to a standardized capture/handling stress protocol. In this Antarctic seabird, we also investigated whether high contaminant burden correlates with a higher occurrence of egg neglect, a frequently observed behavior in snow petrels. POPs and Hg were unrelated to age. Stress-induced corticosterone concentrations were positively related to POPs in both sexes, and stress-induced prolactin concentrations were negatively related to Hg in males. Egg-neglect behavior was not related to POPs burden, but males with higher Hg concentrations were more likely to neglect their egg. This suggests that in birds, relationships between age and contaminants are complex and that even low to moderate concentrations of POPs and Hg are significantly related to hormonal secretion. In this Antarctic species, exposure to legacy POPs and Hg could make individuals more susceptible to environmental stressors such as ongoing disturbances in Polar Regions.