Antarctic marine ecosystems are often considered to be pristine environments, yet wildlife in the polar regions may still be exposed to high levels of environmental contaminants. Here, we measured total mercury (THg) concentrations in blood samples from adult brown skuas Stercorarius antarcticus lonnbergi (n = 82) from three breeding colonies south of the Antarctic Polar Front in the Southern Ocean (southwest Atlantic region): (i) Bahía Esperanza/Hope Bay, Antarctic Peninsula; (ii) Signy Island, South Orkney Islands; and, (iii) Bird Island, South Georgia. Blood THg concentrations increased from the Antarctic Peninsula towards the Antarctic Polar Front, such that Hg contamination was lowest at Bahía Esperanza/Hope Bay (mean ± SD, 0.95 ± 0.45 µg g-1 dw), intermediate at Signy Island (3.42 ± 2.29 µg g-1 dw) and highest at Bird Island (4.47 ± 1.10 µg g-1 dw). Blood THg concentrations also showed a weak positive correlation with δ15N values, likely reflecting the biomagnification process. Males had higher Hg burdens than females, which may reflect deposition of Hg into eggs by females or potentially differences in their trophic ecology. These data provide important insights into intraspecific variation in contamination and the geographic transfer of Hg to seabirds in the Southern Ocean.

International audience | The influence of earthworm activity on soil-to-plant metal transfer was studied by carrying out six weeks mesocosms experiments with or without lettuce and/or earthworms in soil with a gradient of metal concentrations due to particles fallouts. Soil characteristics, metal concentrations in lettuce and earthworms were measured and soil porosity in the mesocosms was determined. Earthworms increased the soil pH, macroporosity and soil organic matter content due to the burying of wheat straw provided as food. Earthworm activities increased the metals concentrations in lettuce leaves. Pb and Cd concentrations in lettuce leaves can increase up to 46% with earthworm activities ... These results and the low correlation between estimated by CaCl2 and EDTA and measured pollutant phytoavailability suggest that earthworm bioturbation was the main cause of the increase. Bioturbation could affect the proximity of pollutants to the roots and soil organic matter.

International audience | The influence of earthworm activity on soil-to-plant metal transfer was studied by carrying out six weeks mesocosms experiments with or without lettuce and/or earthworms in soil with a gradient of metal concentrations due to particles fallouts. Soil characteristics, metal concentrations in lettuce and earthworms were measured and soil porosity in the mesocosms was determined. Earthworms increased the soil pH, macroporosity and soil organic matter content due to the burying of wheat straw provided as food. Earthworm activities increased the metals concentrations in lettuce leaves. Pb and Cd concentrations in lettuce leaves can increase up to 46% with earthworm activities ... These results and the low correlation between estimated by CaCl2 and EDTA and measured pollutant phytoavailability suggest that earthworm bioturbation was the main cause of the increase. Bioturbation could affect the proximity of pollutants to the roots and soil organic matter.

International audience | The use of the Diffusive Gradient in Thin Film sampler (DGT) as a monitoring tool for regulatory programs is currently evaluated. In this context, the impact of commonly followed procedures on the accuracy of DGT-labile As, Cd, Cu, and Ni quantification was studied. Initial sampler contamination yields to define quantification limits instead of using blank subtraction, thus avoiding artifact concentrations. Not considering the alteration of element diffusion by the filter membrane leads to significant underestimation. However, diffusion coefficients determined on a non-fouled membrane were found to be suitable for the studied site, making it possible to use data from the literature. When diffusive boundary layer formation is neglected, no loss of accuracy is recorded provided the layer is thinner than 0.5 mm. Finally, exploration of potential biases allowed initiating a framework that might help limit inaccuracies in DGT-labile concentration estimation and interpretation, especially in a low contamination context.

International audience | Metals are naturally present in freshwater ecosystems but anthropogenic activities like mining operations represent a long-standing concern. Metals released into aquatic environments may affect microbial communities such as periphytic biofilm, which plays a key role as a primary producer in stream ecosystems. Using two 28-day microcosm studies involving two different photoperiods (light/dark cycle of 16/8 vs 8/16), the present study assessed the effects of four increasing nickel (Ni) concentrations (0-6 mu M) on two natural biofilm communities collected at different seasons (summer and winter). The two communities were characterized by different structural profiles and showed significant differences in Ni accumulated content for each treatment. For instance, the biofilm metal content was four times higher in the case of summer biofilm at the highest Ni treatment and after 28 days of exposure. Biomarkers examined targeted both heterotrophic and autotrophic organisms. For heterotrophs, the 8-glucosidase and 8-glucosaminidase showed no marked effects of Ni exposure and were globally similar between the two communities suggesting low toxicity. However, the photosynthetic yield confirmed the toxicity of Ni on autotrophs with maximum inhibition of 81 +/- 7% and 60 +/- 1% respectively for the summer and winter biofilms. Furthermore, biofilms previously exposed to the highest long-term Ni con-centration ([Ni2+] = 6 mu M) revealed no acute effects in subsequent toxicity based on the PSII yield, suggesting a tolerance acquisition by the phototrophic community. Taken together, the results suggest that the biofilm response to Ni exposure was dependent of the function considered and that descriptors such as biofilm metal content could be seasonally dependent, information of great importance in a context of biomonitoring.

International audience | Environmental contamination is one of the major factors or cofactors affecting amphibian populations. Since 2000, the number of studies conducted in laboratory conditions to understand impacts of chemical exposures increased. They aimed to characterize biological effects on amphibians. This review proposes an overview of biological responses reported after exposures to metals, phytopharmaceuticals or emerging organic contaminants and focuses on endpoints relating to reproduction and development. Due to amphibian peculiar features, these periods of their life cycle are especially critical to pollutant exposures. Despite the large range of tested compounds, the same model species are often used as biological models and morphological alterations are the most studied observations. From the results, the laboratory-to-field extrapolation remained uneasy and exposure designs have to be more elaborated to be closer to environmental conditions. Few studies proposed such experimental approaches. Lastly, gametes, embryos and larvae constitute key stages of amphibian life cycle that can be harmed by exposures to freshwater pollutants. Specific efforts have to be intensified on the earliest stages and notably germ cells.

Partitioning tissue metal concentration into subcellular compartments relecting 'toxicologically available'pools may provide good descriptors of the toxicological efects of metals on organisms. Here we investigatedthe relationships between internal compartmentalization of Cd, Pb and Zn and biomarker responses in a model soil organism: the earthworm. The aim of this study was to identify metal fractions reflecting the toxic pressure in an endogeic, naturally occurring earthworm species (Aporrectodea caliginosa) exposed torealistic field-contaminated soils.After a 21 days exposure experiment to 31 field contaminated soils, Cd, Pb and Zn concentrationsin earthworms and in three subcellular fractions (cytosol, debris and granules) were quantified. Differentbiomarkers were measured: the expression of a metallothionein gene (mt), the activity of catalase (CAT) andof glutathione-s-transferase (GST), and the protein, lipid and glycogen reserves. Biomarkers were furthercombined in an integrated biomarker index (IBR).The subcellular fractionation provided better predictors of biomarkers than the total internal contentshence supporting its use when assessing toxicological bioavailability of metals to earthworms. The mostsoluble internal pools of metals were not always the best predictors of biomarker responses. metallothioneinexpression responded to increasing concentrations of Cd in the insoluble fraction (debris + granules). Proteinand glycogen contents were also mainly related to Cd and Pb in the insoluble fraction. On the other hand,GST activity was better explained by Pb in the cytosolic fraction. CAT activity and lipid contents variationswere not related to metal subcellular distribution. The IBR was best explained by both soluble and insolublefractions of Cd and Pb.This study further extends the scope of mt expression as a robust and specific biomarker in an ecologicallyrepresentative earthworm species exposed to field-contaminated soils. The genetic lineage of the individuals,assessed by DNA barcoding with cytochrome c oxidase subunit I, did not inuence mt expression.

International audience | This study aimed at determining the fate of trace elements (TE) following soil organic waste (OW) application. We used a unique combination of X-ray absorption spectroscopy analyses, to determine TE speciation, with incubation experiments for in situ monitoring of TE availability patterns over a time course with the technique of the diffusive gradients in thin films (DGT). We showed that copper (Cu) and zinc (Zn) availability were both increased in OW-amended soil, but their release was controlled by distinct mechanisms. Zn speciation in OW was found to be dominated by an inorganic species, i.e. Zn sorbed on Fe oxides. Zn desorption from Fe oxides could explain the increase in Zn availability in OW amended soil. Cu speciation in OW was dominated by organic species. Cu release through the mineralization of organic carbon from OW was responsible for the increase in Cu availability. (C) 2016 Elsevier Ltd. All rights reserved.

International audience | Bioindicator species are increasingly valuable in environmental pollution monitoring, and elasmobranch species include many suitable candidates for that role. By measuring contaminants and employing biomarkers of effect inrelevant elasmobranch species, scientists may gain important insights about the impacts of pollution in marine ecosystems. This review compiles biomarkers applied in elasmobranchs to assess the effect of pollutants (e.g.,metals, persistent organic pollutants, and plastics), and the environmental changes induced by anthropogenic activities (e.g., shifts in marine temperature, pH, and oxygenation). Over 30 biomarkers measured in more than12 species were examined, including biotransformation biomarkers (e.g., cytochrome P450 1A), oxidative stress-related biomarkers (e.g., superoxide anion, lipid peroxidation, catalase, and vitamins), stress proteins (e.g., heatshock protein 70), reproductive and endocrine biomarkers (e.g., vitellogenin), osmoregulation biomarkers (e.g., trimethylamine N-oxide, Na+/K+-ATPase, and plasma ions), energetic and neurotoxic biomarkers (e.g., lactatedehydrogenase, lactate, and cholinesterases), and histopathological and morphologic biomarkers (e.g., tissue lesions and gross indices).

International audience | Sediment cores from the central Algerian coast were collected to investigate the distribution, sources and risk oftrace metals. The local geochemical background of metals was defined from the core S collected in an uncontaminatedarea of the coast. The anthropogenic inputs in Algiers Bay elevated Ag, Cd, Pb and Zn concentrationsas their maximum were 3.1, 3, 2.1 and 1.8 times the background values, respectively. Meanwhile, increasedcontents of Arsenic (up to 21.1 mg/kg) were detected in all sites. Correlations and PCA suggest that lithogenicsources controlled metal deposition, while most sediment arsenic was agriculture-derived. Organic matter actedas a sink or source for some trace metals. According to EFs, the study area showed slight to moderate enrichmentwith respect to Ag, As, Pb, Cd, Zn and Cu, whereas they remained uncontaminated with Cr, V, Co and Ni. Thisstudy provides a needed baseline for future environmental investigations.