Wide range of metallic and organic contaminants in various tissues of the Antarctic prion, a planktonophagous seabird from the Southern Ocean

International audienceTrace elements (n=14) and persistent organic pollutants (POPs, n=30)were measured in blood, liver, kidney, muscle and feathers of 10 Antarctic prions (Pachyptila desolata) from Kerguelen Islands, southern Indian Ocean, in order to assess their concentrations, tissue distribution, and inter-tissue and inter-contaminant relationships. Liver, kidney and feathers presented the highest burdens of arsenic, cadmium and mercury, respectively. Concentrations of cadmium, copper, iron, and zinc correlated in liver and muscle, suggesting that uptake and pathways of metabolism and storage were similar for these elements. The major POPs were 4,4’-DDE, mirex, PCB-153 and PCB-138. The concentrations and tissue distribution patterns of environmental contaminants were overall in accordance with previous results in other seabirds. Conversely, some Antarctic prions showed surprisingly high concentrations of BDE-209. This compound has been rarely observed in seabirds before, and its presence in Antarctic prions could be due to the species feeding habits or to the ingestion of plastic debris. Overall, the study shows that relatively lower trophic level seabirds (zooplankton-eaters) breeding in the remote southern Indian Ocean are exposed to a wide range of environmental contaminants, in particular cadmium, selenium and some emerging-POPs, which merits further toxicological investigations

A Bayesian framework for estimating parameters of a generic toxicokinetic model for the bioaccumulation of organic chemicals by benthic invertebrates: Proof of concept with PCB153 and two freshwater species

International audienceToxicokinetic (TK) models are relevant and widely used to predict chemical concentrations in biological organisms. The importance of dietary uptake for aquatic invertebrates has been increasingly assessed in recent years. However, the model parameters are estimated on limited specific laboratory data sets that are bounded by several uncertainties. The aim of this study was to implement a Bayesian framework for simultaneously estimating the parameters of a generic TK model for benthic invertebrate species from all data collected. We illustrate our approach on the bioaccumulation of PCB153 by two species with different life traits and therefore exposure routes: Chironomus riparius larvae exposed to spiked sediment for 7 days and Gammarus fossarum exposed to spiked sediment and/or leaves for 7 days and then transferred to a clean media for 7 more days. The TK models assuming first-order kinetics were fitted to the data using Bayesian inference. The median model predictions and their 95% credibility intervals showed that the model fit the data well. From a methodological point of view, this paper illustrates that simultaneously estimating all model parameters from all available data by Bayesian inference, while considering the correlation between parameters and different types of data, is a real added value for TK modeling. Moreover, we demonstrated the ability of a generic TK model considering uptake and elimination routes as modules to add according to the availability of the data measured. From an ecotoxicological point of view, we show differences in PCB153 bioaccumulation between chironomids and gammarids, explained by the different life traits of these two organisms

From Antarctica to the subtropics: contrasted geographical concentrations of selenium, mercury, and persistent organic pollutants in skua chicks (Catharacta spp.)

International audienceSeabirds integrate bioaccumulative contaminants via food intake and have revealed geographical trends of contamination in a variety of ecosystems. Pre-fledging seabird chicks are particularly interesting as bioindicators of chemical contamination, because concentrations in their tissues reflect primarily dietary sources from the local environment. Here we measured 14 trace elements and 18 persistent organic pollutants (POPs) in blood of chicks of skuas that breed in four sites encompassing a large latitudinal range within the southern Indian Ocean, from Antarctica (Adélie Land, south polar skua Catharacta maccormicki), through subantarctic areas (Crozet and Kerguelen Islands, brown skua C. lonnbergi), to the subtropics (Amsterdam Island, C. lonnbergi). Stables isotopes of carbon (δ13C, feeding habitat) and nitrogen (δ15N, trophic position) were also measured to control for the influence of feeding habits on contaminant burdens. Concentrations of mercury (Hg) and selenium (Se) were very high at all the four sites, with Amsterdam birds having the highest concentrations ever reported in chicks worldwide (4.0 ± 0.8 and 646 ± 123 µg g-1 dry weight, respectively). Blood Hg concentrations showed a clear latitudinal pattern, increasing from chicks in Antarctica to chicks in the subantarctic and subtropical islands. Interestingly, blood Se concentrations showed similar between-population differences to Hg, suggesting its involvement in protective mechanisms against Hg toxicity. Chicks’ POPs pattern was largely dominated by organochlorine pesticides, in particular DDT metabolites and hexachlorobenzene (HCB). Skua chicks from subantarctic islands presented high concentrations and diversity of POPs. By contrast, chicks from the Antarctic site overall had the lowest concentrations and diversity of both metallic and organic contaminants, with the exception of HCB and arsenic. Skua populations from these sites, being naturally exposed to different quantities of contaminants, are potentially good models for testing toxic effects in developing chicks in the wild

Prokaryotic, Microeukaryotic, and Fungal Composition in a Long-Term Polychlorinated Biphenyl-Contaminated Brownfield

International audiencePolychlorinated biphenyls (PCBs) are recognized as persistent organic pollutants and accumulate in organisms, soils, waters,and sediments, causing major health and ecological perturbations. Literature reported PCB bio-transformation by fungi andbacteria in vitro, but data about the in situ impact of those compounds on microbial communities remained scarce whilebeing useful to guide biotransformation assays. The present work investigated for the first time microbial diversity from thethree-domains-of-life in a long-term contaminated brownfield (a former factory land). Soil samples were ranked according totheir PCB concentrations, and a significant increase in abundance was shown according to increased concentrations. Microbialcommunities structure showed a segregation from the least to the most PCB-polluted samples. Among the identifiedmicroorganisms, Bacteria belonging to Gammaproteobacteria class, as well as Fungi affiliated to Saccharomycetes classor Pleurotaceae family, including some species known to transform some PCBs were abundantly retrieved in the highlypolluted soil samples

Wandering albatrosses document latitudinal variations in the transfer of persistent organic pollutants and mercury to Southern Ocean predators

International audienceTop marine predators are effective tools to monitor bioaccumulative contaminants in remote oceanic environments. Here, we used the wide-ranging wandering albatross Diomedea exulans to investigate potential geographical variations of contaminant transfer to predators in the Southern Ocean. Blood concentrations of 19 persistent organic pollutants and 14 trace elements were measured in a large number of individuals (N = 180) of known age, sex and breeding status from the subantarctic Crozet Islands. Wandering albatrosses were exposed to a wide range of contaminants, with notably high blood mercury concentrations. Contaminant burden was markedly influenced by latitudinal foraging habitats (inferred from blood δ13C values), with individuals feeding in warmer subtropical waters having lower concentrations of pesticides, but higher concentrations of mercury, than those feeding in colder subantarctic waters. Sexual differences in contaminant burden seemed to be driven by gender specialization in feeding habitats, rather than physiological characteristics, with females foraging further north than males. Other individual traits, such as adult age and reproductive status, had little effect on blood contaminant concentrations. Our study provides further evidence of the critical role of global distillation on organic contaminant exposure to Southern Ocean avian predators. In addition, we document an unexpected high transfer of mercury to predators in subtropical waters, which merits further investigation

A new spiked sediment assay using embryos of the Japanese medaka specifically designed for a reliable toxicity assessment of hydrophobic chemicals

International audienceDespite their low water solubility, hydrophobic pollutants are widespread in the aquatic environment and could represent a threat for living organisms. EU regulations on chemicals require accurate and reliable data on chemical toxicity. Current normalised fish toxicity assays, in particular those advocated by OECD guidelines, do not allow reliable toxicity assessment of hydrophobic compounds due to their low water solubility. In order to accurately evaluate the toxicity of this kind of compounds, a new spiked sediment assay using embryos of the Japanese medaka was developed. It consists of directly exposing fertilised eggs, during their entire embryonic development, onto the reference sediment spiked with the test compound. A large set of lethal or sublethal effects in embryos and newly hatched larvae, including noninvasive endpoints is analysed in order to maximise the sensitivity of the test. The approach was validated using four model pollutants with different modes of action: DMBA, PCB126, PCB153 and 4-nonylphenol (NP). All compounds, except PCB153, induced a dose-dependent increase in toxic effects. In fact, lethal effects only occurred at the highest tested concentration. In contrast, sub-lethal effects including skeletal deformations, cardiac activity modulation, body length reduction and hatching delay were observed at low to moderate concentrations of DMBA and PCB126. NP induced subtle effects in embryos, altering cardiac activity and hatching success but only at high concentrations. Although a few more improvements would make it a fully standardised assay, this spiked sediment assay using medaka embryos proves to be sensitive enough to measure hydrophobic chemical toxicity using an environmentally realistic mode of exposure

Transcriptome profile analysis reveals specific signatures of pollutants in Atlantic eels

Identifying specific effects of contaminants in a multi-stress field context remain a challenge in ecotoxicology. In this context, "omics" technologies, by allowing the simultaneous measurement of numerous biological endpoints, could help unravel the in situ toxicity of contaminants. In this study, wild Atlantic eels were sampled in 8 sites presenting a broad contamination gradient in France and Canada. The global hepatic transcriptome of animals was determined by RNA-Seq. In parallel, the contamination level of fish to 8 metals and 25 organic pollutants was determined. Factor analysis for multiple testing was used to identify genes that are most likely to be related to a single factor. Among the variables analyzed, arsenic (As), cadmium (Cd), lindane (γ-HCH) and the hepato-somatic index (HSI) were found to be the main factors affecting eel's transcriptome. Genes associated with As exposure were involved in the mechanisms that have been described during As vasculotoxicity in mammals. Genes correlated with Cd were involved in cell cycle and energy metabolism. For γ-HCH, genes were involved in lipolysis and cell growth. Genes associated with HSI were involved in protein, lipid and iron metabolisms. Our study proposes specific gene signatures of pollutants and their impacts in fish exposed to multi-stress conditions.Impacts des contaminations métalliques et organiques des systèmes de la Gironde et du St Laurent sur deux espèces en déclin, l'anguille européenne et américaine