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See detailToxicokinetics of selenium in the slider turtle Trachemys scripta
Dyc, Christelle; Far, Johann ULg; Gandar, Frederic ULg et al

in Ecotoxicology (in press)

Selenium (Se) is an essential element that can be harmful for wildlife. However, its toxicity in poikilothermic amniotes, including turtles, remains poorly investigated. The present study aims at ... [more ▼]

Selenium (Se) is an essential element that can be harmful for wildlife. However, its toxicity in poikilothermic amniotes, including turtles, remains poorly investigated. The present study aims at identifying selenium toxicokinetics and toxicity in juvenile slider turtles (age: 7 months), Trachemys scripta, dietary exposed to selenium, as selenomethionine SeMet, for eight weeks. Non-destructive tissues (i.e. carapace, scutes, skin and blood) were further tested for their suitability to predict selenium levels in target tissues (i.e. kidney, liver and muscle) From conservation perspective. 130 juvenile yellow-bellied slider turtles were assigned in three groups of 42 individuals each (i.e. control, SeMet1 and SeMet2). These groups were subjected to a feeding trial including an eight-week supplementation period SP8 and a following four-week elimination period EP4. During the SP8, turtles fed on diet containing 1.1 ± 0.04, 22.1 ± 1.0 and 45.0 ± 2.0 µg.g-1 of selenium (control, SeMet1 and SeMet2, respectively). During the EP4, turtles fed on non-supplemented diet. At different time during the trial, six individuals per group were sacrificed and tissues collected (i.e. carapace, scutes, skin, blood, liver, kidney, muscle) for analyses. During the SP8 (Figure 1), both SeMet1 and SeMet2 turtles efficiently accumulated selenium from a SeMet dietary source. The more selenium was concentrated in the food, the more it was in the turtle body but the less it was removed from their tissues. Moreover, SeMet was found to be the more abundant selenium species in turtles’ tissues. Body condition (i.e. growth in mass and size, feeding behaviour and activity) and survival of the SeMet1 and SeMet2 turtles seemed to be unaffected by the selenium exposure. There were clear evidences that reptilian species are differently affected by and sensitive to selenium exposure but the lack of any adverse effects was quite unexpected. [less ▲]

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See detailThe thyroid gland and thyroid hormones in sheepshead minnow (Cyprinodon variegatus) during early development and metamorphosis
Schnitzler, Joseph ULg; Klaren, Peter; Mariavelle, Emeline ULg et al

in Fish Physiology and Biochemistry (in press)

The sheepshead minnow is widely used in ecotoxicological studies that only recently have begun to focus on disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However ... [more ▼]

The sheepshead minnow is widely used in ecotoxicological studies that only recently have begun to focus on disruption of the thyroid axis by xenobiotics and endocrine disrupting compounds. However, reference levels of the thyroid prohormone thyroxine (T4) and biologically active hormone 3,5,30-triiodothyronine (T3) and their developmental patterns are unknown. This study set out to describe the ontogeny and morphology of the thyroid gland in sheepshead minnow, and to correlate these with whole-body concentrations of thyroid hormones during early development and metamorphosis. Eggs were collected by natural spawning in our laboratory. T4 and T3 were extracted from embryos, larvae and juveniles and an enzyme-linked immunoassay was used to measure whole-body hormone levels. Length and body mass, hatching success, gross morphology, thyroid hormone levels and histology were measured. The onset of metamorphosis at 12-day post-hatching coincided with surges in whole-body T4 and T3 concentrations. Thyroid follicles were first observed in pre-metamorphic larvae at hatching and were detected exclusively in the subpharyngeal region, surrounding the ventral aorta. Follicle size and thyrocyte epithelial cell heights varied during development, indicating fluctuations in thyroid hormone synthesis activity. The increase in the whole-body T3/T4 ratio was indicative of an increase in outer ring deiodination activity. This study establishes a baseline for thyroid hormones in sheepshead minnows, which will be useful for the understanding of thyroid hormone functions and in future studies of thyroid toxicants in this species. [less ▲]

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See detailEVALUATION OF FISH EXPOSURE TO POP-LIKE (ORGANOTIN) COMPOUNDS IN SEPETIBA BAY (RIO DE JANEIRO STATE, BRAZIL) THROUGH HEPATIC TOTAL TIN CONCENTRATIONS
Paiva, TC; Schilithz, PF; Bisi, TL et al

in Organohalogen Compounds (2016, August)

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See detailContrasted accumulation patterns of persistent organic pollutants and mercury in sympatric tropical dolphins from the south-western Indian Ocean
Dirtu, Alin; Malavannan, Govindan; Das, Krishna ULg et al

in Environmental Research (2016), 146

Due to their high trophic position and long life span, small cetaceans are considered as suitable bioindicators to monitor the presence of contaminants in marine ecosystems. Here, we document the ... [more ▼]

Due to their high trophic position and long life span, small cetaceans are considered as suitable bioindicators to monitor the presence of contaminants in marine ecosystems. Here, we document the contamination with persistent organic pollutants (POPs) and total mercury (T-Hg) of spinner (Stenella longirostris, n=21) and Indo-Pacific bottlenose dolphins (Tursiops aduncus, n=32) sampled from the coastal waters of La Réunion (south-western Indian Ocean). In addition, seven co-occurring teleost fish species were sampled and analyzed as well. Blubber samples from living dolphins and muscle from teleosts were analyzed for polychlorinated biphenyls (PCBs), DDT and metabolites (DDTs), chlordanes (CHLs), hexachlorocyclohexanes (HCHs), hexachlorobenzene (HCB), and polybrominated diphenyl ethers (PBDEs). Methoxylated PBDEs (MeO-PBDEs), reported as having a natural origin, were also analyzed. T-Hg levels were measured in blubber and skin biopsies of the two living dolphin species. δ13C and δ15N values were determined in skin of the dolphins and in the muscle of teleosts. For PCBs, HCHs and T-Hg, concentrations were significantly higher in T. aduncus than in S. longirostris. For other POP levels, intra-species variability was high. MeO-PBDEs were the dominant compounds (55% of the total POPs) in S. longirostris, while PCBs dominated (50% contribution) in T. aduncus. Other contaminants showed similar profiles between the two species. Given the different patterns of POPs and T-Hg contamination and the stable isotope composition observed among analyzed teleosts, dietary and foraging habitat preferences possibly explain the contrasted contaminant profiles observed in the two dolphin species. Levels of each class of contaminants were significantly higher in males than females. Despite their spatial and temporal overlap in the waters of La Réunion, S. longirostris and T. aduncus are differently exposed to contaminant accumulation. [less ▲]

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See detailDistribution of inorganic and organic contaminants in the intertidal surface sediments along the Hugli River Estuary, eastern part of India
Das, Krishna ULg; Sarkar, Santosh; Thomé, Jean-Pierre ULg et al

Conference (2016, February 17)

Hooghly estuary and coastal environment in north east coast of India has been strongly affected by the rapid human settlements, intensive boating and tourist activities, deforestation and ongoing ... [more ▼]

Hooghly estuary and coastal environment in north east coast of India has been strongly affected by the rapid human settlements, intensive boating and tourist activities, deforestation and ongoing agricultural and aquacultural practices. The present work investigated trace elements (TEs, T-Hg, Al, V, Cr, Fe, Mn, Cu, Zn, Co, Ni, Ca, Sr, Li, Be, P, Mo, Ag, Cd, Sn, Sb, Ba, Pb, Bi, U, As, Se) and organohalogen compounds in surface sediment (top 0-10cm) considering 8 sampling sites along the Hugli River Estuary (HRE), India. The studied organic compounds include polychlorobiphenyls (PCBs), hexachlorocyclohexane isomers (HCHs), dichlorodiphenyltrichloroethane and metabolites (DDTs) and polybromodiphenyl ethers (PBDEs). Textural analyses of the sediment reveal an overall dominance of mud. All trace elements could be detected at variable concentrations in the following descending order: Al>Fe>Ca> P>Mn> Cu> Zn> Ba >V >Cr>Sr>Ni> Li >Co >Pb>As >Se >U >Be >Sn>Bi >Ag >Mo >Cd >Sb. A synchronous enrichment of majority of the elements were observed at the site Gangasagar (~100 km south megacity Calcutta), situated at the confluence of Hugli River and Bay of Bengal, which might be attributed to cumulative impact of the physicochemical processes and multiple anthropogenic sources. It is revealed that PCBs and DDTs were the dominant compounds among the organic pollutants accounting concentrations up to 23.5 ng.g-1 and 4.4 ng.g-1 respectively at the site Babughat, adjacent to the megacity Calcutta. The results have implications for pollution in complex estuarine environment in a meso-macrotidal setup where there is significant influx of sediments carrying huge load of inorganic and organic pollutants mainly due to rapid urbanization and industrialization. [less ▲]

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See detailMercury and persistent organic pollutant concentrations in free-ranging bottlenose dolphins from Lower Keys and Coastal Everglades (South Florida)
Damseaux, France ULg; Kiszka, Jeremy; Heithaus, Michael et al

Poster (2016, February 12)

The bottlenose dolphin (Tursiops truncatus) is a major apex predator and the most common cetacean species found in nearshore waters of South Florida, including the Lower Florida Keys (LFK) and the Florida ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is a major apex predator and the most common cetacean species found in nearshore waters of South Florida, including the Lower Florida Keys (LFK) and the Florida Coastal Everglades (FCE). The objective of this study was 1) to assess contamination levels of total mercury (T-Hg) in skin and persistent organic pollutants (PCBs, PBDEs, DDT, HCH, HCB, DLCs and PCDD/Fs) in blubber samples of bottlenose dolphins from the LFK (8 males and 16 females) and from the FCE (13 males and 9 females). Pollutants were analysed by the mean of Direct Mercury analyser (for T-Hg), GC-ECD (POPs) and GC-MS (DLCs and PCDD/Fs). The PCBs were the main compounds found in bottlenose dolphins from the LFK and FCE. The most present congeners where the CB no. 28, 52, 101, 138, 153 and 180 (ΣPCBs LFK males: 13420.5 ng.g-1 lipids, ΣPCBs LFK females: 9683.4 ng.g-1 lipids, ΣPCBs FCE males: 5637.9 ng.g-1 lipids, ΣPCBs FCE females: 1426.9 ng.g-1 lipids). PCBs concentrations were significantly higher in individuals from the LFK than those from the FCE but significantly lower than those from other locations in the south-eastern US. Unlike organic pollutants, T-Hg concentrations were significantly higher in FCE male dolphins (LFK: 2936.0 ng.g-1 dw, FCE: 10048.3 ng.g-1 dw). These high concentrations were the highest recorded in the south-eastern US and are most likely due to the presence of mangrove ecosystems. This study highlights the complexity of contaminant dynamics (inorganic vs. organic), even at small spatial scales. [less ▲]

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See detailTransfer of contaminants in the food chain up to marine mammals
Das, Krishna ULg

Conference (2016, February)

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See detailXenobiotic and Immune-Relevant Molecular Biomarkers in Harbor Seals as Proxies for Pollutant Burden and Effects?
Lehnert, Kristina; Ronnenberg, Katrin; Weijs, Liesbeth et al

in Archives of Environmental Contamination & Toxicology (2016), 70(1), 106-120

Harbor seals are exposed to increasing pressure caused by anthropogenic activities in their marine environment. Persistent organic pollutants (POPs) and trace elements are hazardous contaminants which ... [more ▼]

Harbor seals are exposed to increasing pressure caused by anthropogenic activities in their marine environment. Persistent organic pollutants (POPs) and trace elements are hazardous contaminants which accumulate in tissues of harbor seals. POPs and trace elements can negatively affect the immune-system and have been reported e.g. to increase susceptibility to viral infections in seals. Biomarkers of the xenobiotic metabolism, cytokines and heat-shock-protein as cell mediators of the immune-system were established to evaluate the impact of environmental stressors on harbor seals. Harbor seals (n=54) were captured on sandbanks in the North Sea during 2009 to 2012. Medicals including hematology were performed, RNAlater blood samples were taken and analyzed using quantitative Polymerase Chain Reaction. Normalized transcript copy numbers were correlated to hematology and POP concentration in blood, and trace metals in blood and fur. [less ▲]

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See detailEffects of Methylmercury on Harbour Seal Peripheral Blood Leucocytes In Vitro Studied by Electron Microscopy
Dupont, Aurélie; De Pauw-Gillet, Marie-Claire ULg; Schnitzler, Joseph ULg et al

in Archives of Environmental Contamination & Toxicology (2016), 70(1), 133-142

Methylmercury MeHg is highly immunotoxic and can alter the health status of the harbour seal, Phoca vitulina, from the North Sea. To investigate the mechanism of MeHg-induced toxicity in harbour seal ... [more ▼]

Methylmercury MeHg is highly immunotoxic and can alter the health status of the harbour seal, Phoca vitulina, from the North Sea. To investigate the mechanism of MeHg-induced toxicity in harbour seal lymphocytes, ConA-stimulated peripheral blood leucocytes were exposed in vitro to sub-lethal concentrations of MeHgCl (0.2, 1 and 2 µM) for 72h, and then analysed for their viability and ultrastructure. After 72h of incubation, cells were counted with a propidium iodide staining technique, a metabolic MTS assay was performed, and cells exposed to 1 µM MeHgCl were observed by transmission electron microscopy (TEM). Alive cell numbers decreased with increased MeHgCl concentrations. In presence of ConA and 1µM of MeHgCl, TEM images revealed a higher frequency of apoptotic cells. Exposed cells displayed condensation of the chromatin at the nuclear membrane and mitochondrial damages. The results suggest that in vitro MeHgCl induced apoptosis in harbour seal lymphocytes through a mitochondrial pathway. [less ▲]

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See detailSpatial variations in the concentrations of mercury and persistent organic pollutants in free-ranging bottlenose dolphins from South Florida
Das, Krishna ULg; Damseaux, France ULg; Heithaus, M.R. et al

Poster (2015, December)

The bottlenose dolphin (Tursiops truncatus) is an abundant top predator found in nearshore waters of South Florida including heavily developed and remote coastal waters. The objective of this study was to ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is an abundant top predator found in nearshore waters of South Florida including heavily developed and remote coastal waters. The objective of this study was to quantify total mercury (T-Hg) and persistent organic pollutant (POPs: NDL-PCBs, PBDEs, DDT, HCH, HCB, PCDD/Fs and DL-PCBs) levels in bottlenose dolphins found off the highly populated island of Key West (n = 27) and from the undeveloped Florida Coastal Everglades (FCE; n = 20). T-Hg and POPs were analyzed in skin and blubber tissues, respectively, using a Direct Mercury analyzer (for T-Hg), GC-ECD (POPs) and GC-HRMS (DLCs). The 7 ICES PCBs were the main compounds found in bottlenose dolphins from Key West (8229 ng.g-1 lipids) and the FCE (2289 ng.g-1 lipids), while the concentrations of PCDD/Fs remained low (Key West: 104 pg.g-1 lipids, FCE: 102 pg.g-1 lipids). POP concentrations were higher in individuals from Key West compared to those from the FCE. However, POP concentrations in Key West dolphins were lower than those from other locations in Florida and around the world. Unlike organic pollutants, T-Hg concentrations were significantly higher in FCE dolphins (Key West: 2941 ng.g-1 dw versus, FCE: 9314 ng.g-1 dw), with the highest concentrations reported from the southeastern US. PCB concentrations remained under previously suggested threshold for adverse health effects (including immunosuppression) in marine mammals of 17 000 ng/kg lipid. To conclude, sources of T-Hg and POPs differed between Key West and the FCE as reflected by their concentrations in skin and blubber of free-ranging bottlenose dolphins highlighting their role as sentinels of their environment. [less ▲]

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See detail) The spatial variability of trace element bioaccumulation processes: Tools to environmental management
Richir, Jonathan ULg; Lejeune, Lejeune; Lepoint, Gilles ULg et al

Conference (2015, November 07)

As transitional environments, coastal meadows are particularly vulnerable to pollution. Trace elements remain contaminants of concern because of their persistence, their ability to accumulate in biota and ... [more ▼]

As transitional environments, coastal meadows are particularly vulnerable to pollution. Trace elements remain contaminants of concern because of their persistence, their ability to accumulate in biota and their toxicity. Local, regional, national and cross-border programs are thus initiated to monitor their environmental occurrence. Sentinel organisms, or bioindicators, have been widely used to this end since they accumulate the bioavailable and thus potentially toxic fraction of contaminants. In the framework of the STARECAPMED project, the accumulation of trace elements in the seagrass Posidonia oceanica (L.) Delile was studied at different spatial scales: along a radial (100 m scale), in a bay (1 km scale), along the French Mediterranean littoral (10-100 km scale) and along the whole Mediterranean coastline (100-1000 km scale). Results showed that the contamination of the sampled shoots could vary as much at opposite scales. This benthic primary producer accumulates contaminants sequestered in the sediments, in addition to their dissolved fraction in the water column. The sediments also offer a time integration of coastal pollution and thus amplify the pollution signal recorded by the seagrass, resulting in the observed spatial variability. These results demonstrate that the in-depth knowledge of the ecology of the monitored bioindicator and the interactions it shares with its environment cannot be ignored. Such failure could lead to erroneous interpretations of the levels of contamination of monitored sites, and points out the need to define a sampling strategy based on the monitoring objectives and the selected bioindicator. [less ▲]

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See detailSeals as toxicological models to study the transfer of contaminants in the food chain
Das, Krishna ULg

Scientific conference (2015, November 05)

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See detailSpatial variations in concentrations of mercury and persistent organic pollutants in coastal bottlenose dolphins, Tursiops truncatus, from the Lower Florida Keys and the coastal Everglades (South Florida)
Damseaux, France ULg; Kiszka, Jeremy; Heithaus, Michael et al

Conference (2015, October 09)

The bottlenose dolphin (Tursiops truncatus) is a major apex predator and the most common cetacean species found in nearshore waters of South Florida, including the Lower Florida Keys (LFK) and the ... [more ▼]

The bottlenose dolphin (Tursiops truncatus) is a major apex predator and the most common cetacean species found in nearshore waters of South Florida, including the Lower Florida Keys (LFK) and the Everglades National Park (ENP). The objective of this study was 1) to assess contamination levels of total mercury (T-Hg) in skin and persistent organic pollutants (PCBs, PBDEs, DDT, HCH, HCB, DLCs and PCDD/Fs) in blubber samples of bottlenose dolphins from the LFK (T-Hg : nmales = 10; POPs : nmales = 16, nfemales = 8) and the ENP (T-Hg : nmales = 13, nfemales = 9; POPs : nmales = 11, nfemales = 8). T-Hg and POPs were analysed by the mean of Direct Mercury analyser (for T-Hg), GC-ECD (POPs) and GC-MS (DLCs and PCDD/Fs). The PCBs were the main compounds found in bottlenose dolphins from the LFK and ENP. The most present congeners where the CB no. 28, 52, 101, 138, 153 and 180 (Σ 6 PCBs LFK males: 13420.5 ng.g-1 lipids, Σ 6 PCBs LFK females: 9683.4 ng.g-1 lipids, Σ 6 PCBs ENP males: 5637.9 ng.g-1 lipids, Σ 6 PCBs ENP females: 1426.9 ng.g-1 lipids), while the concentrations of DL PCBs remained low for both locations (LFK: 739 ng.g-1 lipids, ENP: 183 ng.g-1 lipids). PCBs concentrations were significantly higher in individuals from the LFK than those from the ENP. PCBs concentrations in LFK and ENP dolphins were significantly lower than those from other locations in the south-eastern US. Unlike organic pollutants, T-Hg concentrations were significantly higher in ENP male dolphins (LFK: 2936.0 ng.g-1 dw, ENP: 10048.3 ng.g-1 dw). These high concentrations were the highest recorded in the south-eastern US and are most likely due to the presence of mangrove ecosystems. This study highlights the complexity of contaminant dynamics (inorganic vs. organic), even at small spatial scales. [less ▲]

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See detailApplying Stable Isotopes Bayesian Ellipses (SIBER) to characterise trophic niches of large cetaceans from the north-Western Medterranean Sea
Pinzone, Marianna ULg; Michel, Loïc ULg; Ody, Denis et al

Poster (2015, October 08)

Diet composition and feeding preferences are of critical importance to understand a species' ecology; better knowledge of these matters is necessary for efficient conservation. Few is known on the trophic ... [more ▼]

Diet composition and feeding preferences are of critical importance to understand a species' ecology; better knowledge of these matters is necessary for efficient conservation. Few is known on the trophic ecology of Mediterranean cetacean populations and the elusiveness of these organisms limits acquisition of new information. Here, we analysed C and N isotopic ratios of skin biopsies of 17 fin whales Balaenoptera physalus, 15 long-finned pilot whales Globicephala melas and 25 sperm whales Physeter macrocephalus sampled through darting between summer 2010 and 2013 in the North-Western Mediterranean Sea. We subsequently used the SIBER R package to explore isotopic niche parameters as a proxy for trophic niches assessment. Fitting of standard ellipses to each species revealed that no niche overlap between the odontocetes and fin whales was present, in accordance with the lower trophic level of the latter. Moreover, overlap between the isotopic niches of the two odontocetes was limited, confirming resource partitioning between these two species. This could be linked with differences in hunting periods and depths and consequently in prey availability. Bayesian modelling of standard ellipses revealed that the isotopic niche of fin whales was larger than the two odontocetes in over 99.80% of 106 model simulations. It is the first time that such variability is observed in Mediterranean fin whales. This suggests possible exploitation of food items from different trophic levels (krill, small fishes) or from other regions, such as other areas in the Mediterranean Sea and the North-East Atlantic. Modelling also suggested that no meaningful differences were present in the width of isotopic niches of the two odontocetes. The very narrow isotopic niche of pilot whales is in strong contrast with the generalist feeding behaviour this species is believed to have according to literature analysis. Our results open new perspectives on the ecological role of Mediterranean cetaceans. [less ▲]

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See detailDGTs, a complementary tool towards more efficient biomonitoring practices
Richir, Jonathan ULg; Lepoint, Gilles ULg; Donnay, Annick et al

Conference (2015, October 01)

Among the diversity of contaminants, trace elements (TEs) remain of concern because of their persistence, their ability to accumulate in biota and their toxicity. The direct measurement of their dissolved ... [more ▼]

Among the diversity of contaminants, trace elements (TEs) remain of concern because of their persistence, their ability to accumulate in biota and their toxicity. The direct measurement of their dissolved concentrations only gives punctual and fluctuating information, and often remains below detection limits of analytical methods. The more appropriate use of sentinel organisms, or bioindicators, to monitor TEs has thus often been preferred in environmental surveys. The introduction of the diffusive gradients in thin films (DGTs) technique has however participated to progressively change this binary view - bioindicator vs water - of the coastal monitoring of TEs, and DGTs rapidly became a relevant complementary tool to bioindicators, has illustrated below. In the framework of the STARECAPMED project, the ecology and the ecotoxicology of TEs were studied in the seagrass Posidonia oceanica (L.) Delile and the mussel Mytilus galloprovincialis Lamarck, 1819. DGTs (free- and pore-water probes) were deployed before sampling of organisms. TEs were also analyzed in suspended matter (dissolved and suspended-particulate TE speciation). Studies were performed in the Calvi Bay (Corsica, France), northwestern Mediterranean. TE concentrations in organisms and suspended matter or in DGT resins were measured by DRC-ICP-MS after HNO3/H202 mineralization or after a 24h elution in HNO3 1M, respectively. (1) TE bioaccumulation was first seasonally studied in P. oceanica over 3 years. Dissolved TE concentrations monitored with DGTs were low to very low. TE bioaccumulation dynamics in P. oceanica could thus be linked to the natural physiological cycle of the plant, in clean environmental conditions. (2) To complement that field survey, isolated seagrasses were in situ contaminated with TEs at environmental relevant concentrations. Through the use of DGTs, TE uptake kinetics were modelled for seagrasses exposed to know bioavailable concentrations of contaminants, as were loss kinetics during the following depuration phase. The TE sequestration ability of a healthy P. oceanica meadow facing sudden trace metal contamination events could also be quantified. (3) The deployment of pore-water DGT probes in bare-sand or seagrass colonized sediments further showed that, through its stabilizing function of the seabed, P. oceanica maintained higher TE levels in the pore-water. P. oceanica meadows thus offer a significant “depuration-filtering” ecological service along highly anthropized Mediterranean coasts. M. galloprovincialis are widely used in large spatial scale coastal monitoring surveys. (4) The deployment of caged mussels together with DGTs showed that the little contaminated water body of the Calvi Bay was relatively homogenous. It also allowed to calculate TE bioaccumulation towards mussels in reference conditions, and to compare it to native mussel populations. (5) Finally, during a 5 months mussel caging survey, mussels and suspended matter were collected weekly to monthly, such as were deployed DGTs. The physiological status of mussels, the speciation of TEs between their dissolved and suspended-particulate phases, and their relative influence on TE bioaccumulation dynamics in mussels were investigated. In conclusion, these case studies properly demonstrate how DGT probes can be used as a relevant and complementary tool to bioindicators. Their concomitant use should therefore be privileged in monitoring surveys. [less ▲]

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See detailAnthropogenic particles in stomachs of anchovies (Engraulis encrasicolus) related to gill rakers morphology
Collard, France ULg; Das, Krishna ULg; Gilbert, Bernard ULg et al

in Proceedings of In the Wake of Plastics, Venice, October 13-15, 2015 (2015, October)

Anthropogenic debris (AB) contaminate oceans and affect marine organisms in several ways. Plastic production is constantly increasing and it is estimated that 10% of this production end in the seas. As a ... [more ▼]

Anthropogenic debris (AB) contaminate oceans and affect marine organisms in several ways. Plastic production is constantly increasing and it is estimated that 10% of this production end in the seas. As a consequence, plastic is considered as an emerging contaminant and ingestions by organisms are increasingly reported. Microdebris (< 5mm) are available for a high range of organisms, including planktivorous fish, such as the European anchovy (Engraulis encrasicolus). Planktivorous fish have a particular gill basket, with long and tight gill rakers, related to their diet. Upon these gill rakers, small structures called denticles are present. These gill rakers act as a net to trap organic particles and AB. The aim of our study was to correlate sizes of AB ingested with the mesh constituted by the gill rakers and associated structures. Fifteen stomach contents were analyzed by Raman spectroscopy and particles were measured. Five gill arches were observed with a scanning electron microscope. Cellulose fibers and microplastics were the most AB ingested. Comparing to other Clupeiformes (pilchard and Atlantic herring), anchovies have more denticles on each gill rakers (personal data). AB ingestion by fish is poorly studied and impacts of AB are not much understood. Clupeiformes play a major role in marine ecosystems and is the most consumed order by humans. As the branchial basket constitutes a food selective apparatus, more morphological studies dealing with AB ingestion on Clupeiformes are needed. [less ▲]

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See detailTriclosan retardes development of Sheepshead minnow (Cyprinodon variegatus)
Dussenne, Mélanie ULg; Frederich, Bruno ULg; Das, Krishna ULg et al

Conference (2015, October)

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS), with his chemical structure similar to thyroid hormones (THs), may have ... [more ▼]

The aquatic environment represents the final sink for many chemicals, including bactericidal agents. Among them Triclosan (TCS), with his chemical structure similar to thyroid hormones (THs), may have adverse effects on the thyroid system. The study we carried out aims to evaluate the effects of TCS exposure on development of Cyprinodon variegatus, a fish model used in ecotoxicological studies. We investigated the potential effects of TCS on C. variegatus during two key periods; embryonic development and metamorphosis. We exposed eggs and larvae to environmental relevant concentrations. We showed that TCS had no effect on reproduction parameters, such as egg fertility or survival rate of larvae. However, we highlighted the fact that hatching of exposed larvae was delayed of around 6 to 13 hours compared to control embryos. During the larval phase, measurements of THs levels were performed. We showed that TCS affected the typical ontogenic variations of the whole body thyroid hormones concentrations during metamorphosis. As THs are known to control somatic growth and development, we tested the effects of TCS exposure on morphological development. We observed no deformity or malformation, but we revealed a developmental retardation in larvae exposed to TCS, of around 18 to 32 hours. Such a developmental delay had never been highlighted in previous studies on TCS exposed fish. We hypothesize that the disruption of THs homeostasis affects the timing of the start of metamorphosis. As a consequence, exposed larvae showed an extended larval phase compared to the control group. The harmful effects of TCS on physiology and development are a major concern, as marine organisms are constantly exposed to it. Furthermore, strong connections exist between thyroid and reproductive system, which might have deleterious effects on population dynamics. [less ▲]

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See detailDetection of anthropogenic particles in fish stomachs: an isolation method adapted to identification by Raman spectroscopy
Collard, France ULg; Gilbert, Bernard ULg; Eppe, Gauthier ULg et al

in Archives of Environmental Contamination & Toxicology (2015), 69

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