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The growing use of Lanthanides in new technologies has increased their anthropogenic releases into the aquatic environment over the last decades. However, knowledge on their ecotoxicological impacts is still incomplete, especially with regard to biological effects of Lanthanides mixtures and the possible regular variation in toxicity along the Lanthanides series. The present study evaluated the individual toxicity of all Lanthanides and the toxicity of mixtures of three of them, namely Neodymium (Nd

Despite the involvement of several serine hydrolases (SHs) in the metabolism of xenobiotics such as dibutyl phthalate (DBP), no study has focused on mapping this enzyme class in zebrafish, a model organism frequently used in ecotoxicology. Here, we survey and identify active SHs in zebrafish larvae and search for biological markers of SH type after exposure to DBP. Zebrafish were exposed to 0, 5, and 100 µg/L DBP from 4 to 120 h post-fertilization. A significant decrease in vitellogenin expression level of about 2-fold compared to the control was found in larvae exposed to 100 µg/L DBP for 120 h. The first comprehensive profiling of active SHs in zebrafish proteome was achieved with an activity-based protein profiling (ABPP) approach. Among 49 SHs identified with high confidence, one was the carboxypeptidase ctsa overexpressed in larvae exposed to 100 µg/L DBP for 120 h. To the best of our knowledge, this is the first time that a carboxypeptidase has been identified as deregulated following exposure to DBP. The overall results indicate that targeted proteomics approaches, such as ABPP, can, therefore, be an asset for understanding the mechanism of action related to xenobiotics in ecotoxicology.

International audience; The rapid development of nanotechnology and the increased use of nanomaterials in products used in everyday life have raised the question of the potential release of nanoparticles into the aquatic environment. Their fate and effects in natural ecosystems are not currently well understood but harmful effects of nanoparticles have been demonstrated at low concentrations on some freshwater and marine species. Cerium dioxide nanoparticles (CeO2 NPs) are produced in large quantities and used in products in many different fields, such as automotives or optics. Because of their widespread use in daily products, CeO2 NPs are included in the OECD priority list of manufactured nanomaterials for human and environmental assessment. Indeed some studies have been conducted to assay various enzymatic biomarkers, which showed the CeO2 NPs potential to modify anti-oxidative defenses and cellular membrane stability. Nevertheless, only a few studies were performed on their genotoxic potential. The aim of this work was to evaluate the genotoxic and physiological effects of CeO2 NPs on a widespread freshwater bivalve Corbicula fluminea by using comet assay and a multi-enzymatic biomarker approach. Exposure to two CeO2 NP concentrations during a short term experiment (6 days) was set up. The first one (10 μg/L) was chosen in order to work with low but measurable concentrations whereas the second one was ten times higher (100 μg CeO2 NPs/L). DNA damage was significantly more pronounced compared with control for both concentrations tested as early as two days of exposure and seemed to increase with time. Some enzymatic biomarkers of anti-oxidative defenses (total antioxidant capacity, catalase activity), anti-toxic mechanisms (glutathione-S-transferase activity, caspase-3 activity) or metabolism (lactate dehydrogenase activity) tended to increase after 6 days of exposure but only the induction of caspase pathway and DNA damages appeared significant for exposed organisms. In this study, time and concentration effects of CeO2 NPs were highlighted by coupling genotoxic and cellular biomarker assessments.

In this study, the presence of anthropogenic gadolinium (Gd) was evaluated in rivers, close to wastewater treatment plant outputs. Then, one site was selected for in situ experiments to assess the bioaccumulation of Gd in the digestive gland and in the gills of two bivalves (Dreissena rostriformis bugensis and Corbicula fluminea). For both organisms, the results suggested that the bioaccumulation of Gd can be observed when organisms are exposed in a geogenic and anthropogenic Gd mixture. In order to observe if Gd can bioaccumulate in tissues of bivalves when the ion is only present as the main anthropogenic speciation of Gd, i.e., Gd-contrast agents (Gd-CAs), the gadoteric acid was used for a laboratory experiment. In this case, the presence of Gd was clearly detected in a significant amount in the digestive glands of D. rostriformis bugensis and C. fluminea while low concentrations are measured in the gills. For the first time, these results clearly showed that Gd can bioaccumulate in bivalve tissues even when it is only present as Gd-CAs. Biochemical activities were measured in the digestive gland and in the gills of the bivalves to assess the effects of Gd-CA bioaccumulation. No significant variations were observed in the gills. Concerning the digestive gland, after 7 days of exposure at 10 μg L-1 of Gd as Gd-CA speciation, GST activity in D. rostriformis bugensis and lipid hydroperoxide and mitochondrial electron transfer system in C. fluminea had increased. The results suggest an acclimation of the organisms to the presence of Gd-CAs in the medium within less than 21 days.

International audience; The present study was the first approach conducted under environmental concentrations of Gd-DOTA and Gd-DTPA-BMA to assess cellular impacts of these compounds. Gd-DOTA (Gadoteric acid) is one of the most stable contrast agent, currently used as Dotarem® formulation during Magnetic Resonance Imaging exams. The study was mainly performed on a Zebra Fish cell line (ZF4; ATCC CRL-2050). At the concentrations of 0.127 nM and 63.59 nM (respectively 20 ng and 10 μg of Gd/L), we did not observed any toxicity of Dotarem® but a slowdown of the cell growth was clearly measured. The effect is independent of medium renewing during 6 days of cell culturing. The same effect was observed i-with Gd-DOTA on another fish cell line (RT W1 gills; ATCC CRL-2523) and ii-with another contrast agent (Gd-DTPA-BMA - Omniscan®) on ZF4 cells. On the ZF4 cell line, the diminution of the cell growth was of the same order during 20 days of exposure to a culture medium spiked with 63.59 nM of Dotarem® and was reversible within the following 8 days when Dotarem® was removed from the medium. As shown by using modified DOTA structure (Zn-DOTA), the effect may be due to the chelating structure of the contrast agent rather than to the Gd ion. Until now, the main attention concerning the impact of Gd-CA on living cells concerned the hazard due to Gd release. According to our results, quantifying the presence of Gd-CA chelating structures in aquatic environments must be also monitored.

International audience; Organisms commonly face multiple stresses in ecosystems, among which are toxic substances that add to natural ecological constraints such as insufficient resource quality. The combined effects of these stressors on species and ecosystems remain poorly investigated. We hypothesised that feeding on high‐quality resources in terms of phosphorus (P) content will improve the physiological state of consumers and thus increase tolerance to episodic metal stress by silver (Ag). We used a detritivorous crustacean from streams, Gammarus fossarum, to test this hypothesis. The experimental design involved two phases. In the first phase, gammarids were fed ad libitum for 15 days to evaluate the effect of food quality on their energetic status. Gammarids were placed in laboratory microcosms and allowed to feed on two leaf species, alder and sycamore, that were colonised by aquatic fungi and experimentally enriched with P. At the end of this feeding period, we determined (i) food consumption, (ii) energetic reserves and (iii) physiological and behavioural states. In the second phase, gammarids previously consuming food of different quality were exposed to dissolved Ag (0, 0.5 and 1 μg L−1) for 4 days to investigate the physiological and behavioural responses of the consumers. Elevated P concentrations in leaf litter increased the energetic reserves and locomotor activity of G. fossarum. Gammarids exposed to Ag had a low glycogen content, regardless of the Ag concentration and leaf P concentration, suggesting significant energy allocation to several aspects of organism maintenance (e.g. detoxification or compensatory mechanisms). In most cases, this investment appeared to prevent gammarids from carrying out lipid peroxidation (indicating cell membrane damage), except for those gammarids feeding on leaves with the highest P concentration. Higher energetic storage (measured as glycogen content), related to higher elemental food quality, did not lead to a systematic increase in consumer tolerance to Ag, gammarids being unable to compensate for negative effects of Ag at the concentrations tested.

44 pages, 4 figures, 7 tables, Lanthanide (LNs) release into the environment is expected to greatly increase in the coming years due to a high demand for new technologies. However there is a gap in the ecological risk assessment of these metals because most of the ecotoxicological studies have been performed with only one element, although they are usually found in nature as a group. This research evaluated the effects of mixtures of three lanthanides, cerium (Ce), gadolinium (Gd), and lutetium (Lu), representative of the light, middle and heavy rare earth elements, respectively, on seven aquatic species (A. fischeri, R. subcapitata, C. vulgaris, B. calyciflorus, H. incongruens, D. magna and D. rerio). Lanthanide content decreased over time in all toxicity test media and it was observed that LN sedimentation starts at the beginning of the tests with a steep decline of the available LN amount. Potential toxic effects of LNs were observed only in five species of the seven studied, predominantly in the unicellular organism (A. fischeri) and in the organisms belonging to the lower trophic levels (R. subcapitata and B. calyciflorus). The multi-toxicity approach performed in this study showed synergistic effects in tests performed with the bacteria A. fischeri and the algae R. subcapitata, and antagonistic effects for the rotifer B. calyciflorus. Although predicting the response of aquatic organisms exposed to multi-elements is not an easy task and can be masked by potential interactions with other compounds or even by nutrient removal. The variation in toxic action among species observed in this study reveals that lanthanide interaction in toxicity mechanisms should not be discarded, and supports that further studies with LN mixtures are required to properly understand their toxic behaviour in nature ecosystems.

International audience; Rare earth element (REE) concentrations were determined for 22 sites sampled during two water periods: high flow in winter and low flow in summer. Shale-normalized REE patterns of all samples displayed positive gadolinium (Gd) anomalies. They revealed a widespread contamination of anthropogenic Gd (Gdant) from waste water treatment plant (WWTP) outputs to catchment areas used for drinking water. No significant variations in Gdant were observed between the two flow water periods, but differences in the Gd anomalies were present. However, these differences seem to be associated rather with seasonal variations in the river flow rate than with the release of GdAnt from WWTPs. In proximity to WWTP discharges, strong GdAnt variations ranged from few nanograms per litre to more than 80 μg L-1 and rarely showed a repetitive pattern day after day during 14 days. These concentrations were diluted into the river stream and measured around 10 ng L-1 close to the catchment areas used for drinking water. A principal component analysis (PCA) using the GdAnt concentrations and some classical physicochemical parameters (pH, water temperature, total alkalinity (TA), total organic carbon (TOC), biochemical and chemical oxygen demand (BOD and COD), Cl-, NO3- and SO42-) allowed a site separation according to the level of Gd contamination, highlighting that the highest GdAnt concentrations were found in the north of the region Lorraine (France) where the population density is high and most of the MRI examinations are performed.

The rapid development of nanotechnology and the increased use of nanomaterials in products used in everyday life have raised the question of the potential release of nanoparticles into the aquatic environment. Their fate and effects in natural ecosystems are not currently well understood but harmful effects of nanoparticles have been demonstrated at low concentrations on some freshwater and marine species. Cerium dioxide nanoparticles (CeO

We investigated the influence of the acanthocephalan parasite Polymorphus minutus on the mortality of its intermediate host, Gammarus roeseli, exposed to cadmium, by the measure of LC(50-96h) values as well as the bioaccumulation of cadmium both in the host and in its parasite. LC(50) results revealed that infected G. roeseli males died less under cadmium stress than uninfected ones; while the converse has been observed in females. Cadmium resistance of infected males could be explained by a weaker bioconcentration factor (BCF) than in females. The lower BCF in infected individuals was closely related with an uptake of cadmium by P. minutus in its host. Nevertheless, although infected females had both weaker BCF and cadmium concentration in their body, the presence of P. minutus did not induce lower mortality than uninfected females. On the contrary, their sensitivity to cadmium was increased by the presence of P. minutus. We discuss the hypothesis that differences of mortality between uninfected and infected gammarids could be explained by a difference of cadmium bioconcentration in host, and by the cadmium bioaccumulation in the parasite. Indeed, results suggested that P. minutus could help G. roeseli to face with stress, what contributed to keep the host alive and favour the parasite transmission.

SUMMARYIn disturbed environments, infected organisms have to face both parasitic and chemical stresses. Although this situation is common, few studies have been devoted to the effects of infection on hosts' energy reserves and antitoxic defence capacities, while parasite survival depends on host survival. In this study, we tested the consequences of an infection by Polymorphus minutus on the energy reserves (protein, lipid and glycogen) and antioxidant defence capacities (reduced glutathione, γ-glutamylcysteine ligase activity) of Gammarus roeseli males and females, in the absence of chemical stress. Moreover, malondialdehyde concentration was used as a toxicity biomarker. The results revealed that in infected G. roeseli, whatever their gender and the sampling month, protein and lipid contents were lower, but glycogen contents were higher. This could be explained by the fact that the parasite diverts part of the host's energy for its own development. Moreover, glutathione concentrations and γ-glutamylcysteine ligase activity were both lower, which could lead to lower antitoxic defence in the host. These results suggest negative effects on individuals in the case of additional stress (e.g. pollutant exposure). In the absence of chemical stress, the lower malondialdehyde level in infected gammarids could imply a probable protective effect of the parasite.

For 20 years, many articles report the presence of new compounds, called "emerging compounds", in wastewater and aquatic environments. The US EPA (United States - Environmental Protection Agency) defines emerging pollutants as new chemicals without regulatory status and which impact on environment and human health are poorly understood. The objective of this work was to identify data on emerging pollutants concentrations in wastewater, in influent and effluent from wastewater treatment plants (WWTPs) and to determine the performance of sewage disposal. We collected 44 publications in our database. We sought especially for data on phthalates, Bisphenol A and pharmaceuticals (including drugs for human health and disinfectants). We gathered concentration data and chose 50 pharmaceutical molecules, six phthalates and Bisphenol A. The concentrations measured in the influent ranged from 0.007 to 56.63 μg per liter and the removal rates ranges from 0% (contrast media) to 97% (psychostimulant). Caffeine is the molecule whose concentration in influent was highest among the molecules investigated (in means 56.63 μg per liter) with a removal rate around 97%, leading to a concentration in the effluent that did not exceed 1.77 μg per liter. The concentrations of ofloxacin were the lowest and varied between 0.007 and 2.275 μg per liter in the influent treatment plant and 0.007 and 0.816 μg per liter in the effluent. Among phthalates, DEHP is the most widely used, and quantified by the authors in wastewater, and the rate of removal of phthalates is greater than 90% for most of the studied compounds. The removal rate for antibiotics is about 50% and 71% for Bisphenol A. Analgesics, anti inflammatories and beta-blockers are the most resistant to treatment (30-40% of removal rate). Some pharmaceutical molecules for which we have not collected many data and which concentrations seem high as Tetracycline, Codeine and contrast products deserve further research.

In gammarids, behavioural and biochemical biomarkers are commonly used in ecotoxicological studies. In our study, we have investigated seasonal variations of several biochemical biomarkers in Gammarus roeseli, a freshwater species. Organisms were sampled monthly over a 1-year period. Gender was distinguished to measure antioxidant enzyme activities like total glutathione peroxidase (GPxtot), selenium-dependent glutathione peroxidase (SeGPx) and catalase enzymes, lipoperoxidation end-product (malondialdehyde, MDA), and energy reserves with protein and lipid contents. In the same time, usual water physico-chemical parameters were measured at the sampling site. A based-gender difference was observed for parameters related to oxidative stress. Females showed higher antioxidant enzyme activities and lower MDA level than males. Parameters related to oxidative stress and energy reserves appeared correlated with temperature and physiological status of organisms. Females GPx activities were lower in autumn and winter when no breeding occurred. In both gender, MDA levels were correlated with temperature with an increase of lipoperoxidation in summer. Lipid contents were the lowest in summer and the highest in winter, probably due to the reproductive status of organisms and their feeding behaviour. Gender-based differences of biochemical parameters suggest a specific sensitivity of males and females in ecotoxicological experiments. Moreover, organisms could be more vulnerable in summer when MDA levels are high and energy reserves low. Deleterious effect of xenobiotics would be different with gender and season.

The aim of this study was to examine genotoxic effects of nickel (Ni=105 mg kg(-1)), trivalent and hexavalent chromium (Cr=491 mg kg(-1)) on the Eisenia fetida earthworm after 2 and 4d of exposure to two different spiked soils (an artificial (OECD) and a natural one). DNA damages were evaluated on the earthworm's coelomocytes using the comet assay. After an exposure into OECD spiked soils, Ni did not induce genotoxic effect whereas Cr(III) and Cr(VI) revealed to be genotoxic after 2d of exposure. After 4d of exposure, only Cr(VI) still induced significant damages. In natural spiked soils, nickel and Cr(III) revealed to be genotoxic after 2 and 4d of exposure. Concerning Cr(VI) toxicity, all the earthworms died after 1d of exposure. These results underline the importance to take into account the nature and the speciation of metallic pollutants, although the experiment has been performed on spiked soil with higher bioavailibity than in contaminated natural soil.

Artificial streams are dynamic mesocosms, simulating aquatic systems and rivers. They are useful to study ecotoxicity of chemicals and their effects on flora and fauna colonizing the streams or introduced into the channels. These artificial rivers can also be used to study the influence of ecological and hydrodynamic parameters, such as the kind of substrate of river and flow rate. Responses of the bivalve Unio tumidus to substrate type (silt, sand, and pebbles) and water flow rate (high and low) were investigated after 15 and 35 days in the channels, in order to optimize the experimental conditions for ecotoxicity study with methyl methacrylate (MMA). The toxicological effects of different concentrations of MMA on bivalves and on communities of invertebrates and diatoms were determined after several weeks of exposure at a high flow rate. Biomarkers responses measured in the digestive gland and the gills of U. tumidus were the activities of detoxification systems as early indicators of toxicity and lipid peroxidation as a marker of cytotoxicity. Effects of MMA resulted in a decrease in antioxidant activities. Disturbances in bivalves appeared at lower concentrations than in communities. This indicates sensitivity of the biomarkers studied, which are predictive indicators of ecotoxicity.

Links among metal exposure, metal accumulation, and metal-induced effects were explored in indigenous yellow perch (Perca flavescens) collected from eight lakes located along a metal concentration gradient in two mining regions. Fish exposure to Cd, Cu, Ni, and Zn was estimated on the basis of calculated free metal ion concentrations in lake waters. Hepatic metal concentrations were determined and various markers of oxidative stress were measured to assess metal effects in liver cells. Accumulated metals were not consistently related to ambient free metal ion concentrations, possibly because of unaccounted for fluctuations in lake water metal concentrations. Accumulated metals were associated with limited oxidative stress in perch livers, as evidenced by reductions in glutathione concentrations and glutathione reductase activities. However, this stress appeared to be minor, since increasing hepatic Cu concentrations were associated with reduced lipid peroxidation, a response opposite to that predicted from basic principles. Our results suggest that oxidative stress will not have direct repercussions on the health of the perch at the individual level. We speculate that the observed increase in metallothionein concentrations with increasing accumulated metals might afford protection against reactive oxygen species.

This research aimed to estimate potential genotoxicity for consumers resulting from the ingestion of seafood contaminated with polycyclic aromatic hydrocarbons (PAHs) released into the marine environment after the 'Erika' shipwreck along the coasts of south Brittany, in France. Mussels (Mytilus sp.) collected from sites on the Atlantic coast that were affected by the oil slick in various degrees, were used to feed rats daily for 2 and 4 weeks. DNA damage was measured by use of the Comet assay in the liver, bone marrow and blood of rats receiving food contaminated with 312 microg of 16PAHs/kg dry weight (d.w.) equivalent to 33.8 microg TEQs (toxic equivalent quantities to benzo(a)pyrene (BaP))/kg d.w. mussels, 569 microg/kg d.w. (83.6 microg TEQs/kg) and 870 microg/kg d.w. (180.7 microg TEQs/kg). A dose-effect-time relationship was observed between the amount of DNA damage in the liver and bone marrow of the rats and the PAH contamination level of the mussels. Genotoxicity increased during the period between 15 and 30 days in rats that received food at the highest two PAH levels. On the other hand, no significant change in liver and bone marrow of rats fed with mussels containing 33.8 microg TEQs/kg d.w. was recorded at 30 days compared with 15 days, indicating efficient DNA repair capacity at low levels of exposure. No signs of genotoxicity were found in peripheral blood. Globally, the observed effects were rather moderate. These results show that oil-contaminated food caused DNA damage in predators, and underline the bioavailability to consumers of pollutants in mussels contaminated with fuel oil. The usefulness of the Comet assay as a sensitive tool in biomonitoring studies analyzing responses of PAH transfer through food webs was also confirmed.

The transfer of polycyclic aromatic hydrocarbons (PAHs) from bivalves, through the food chain to verte- brates was of concern. Our research aimed at estimating potential effects for consumers resulting from the ingestion of seafood contaminated by oil spill pollutants. After the "Erika" wreck, mussels (Mytilus sp.) were collected from sites of the Atlantic coast impacted to various degrees by the oil slick and constituted contaminated food for rats during 2 and 4 weeks. Genotoxic damage were studied in rats by means of COMET assay carried out in liver, bone marrow and peripheral blood. Biochemical and genomic effects such as the induction of CYP 1A1 and the expression of cytochrome genes were measured in rat livers. The most sensitive biological parameter reflecting the transfer of contaminants via the food appeared to be DNA breaks studied by means of the COMET assay. Genotoxic damage, observed mainly in the liver, were rather moderate and remained not persistent. This study underlined the bioavailability of pollutants in fuel oil contaminated mussels for consumers, and the complexity of the contamination consecutive to the oil spill. The occurrence of related PAH compounds in addition to non-substituted PAHs in fuel oils and mussels raised the question of their implication in the registered effects.

This study addresses the question of the relation between cellular and genomic oxidative damages in freshwater bivalves in realistic conditions of exposure in the field. Membrane and genomic oxidative damages were studied by means of lipid peroxidation and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo), respectively. Malondialdehyde (MDA) was used as an indicator of lipid peroxidation. The biomarkers were measured in the digestive gland and the gills of mussels (Unio tumidus) after 7 and 21 days of exposure in four ponds of the Moselle Basin, during three field studies conducted in 1999 and 2000. Effects measured at three sites (1R, 3C and 4M) were moderate and lipid peroxidation was slightly enhanced in mussels transferred in these ponds. In contrast, an important degradation was observed at site 2V reflected by a sharp increase in MDA and 8-oxodGuo concentrations in 2000. The biomarker responses agreed with the results of physicochemical analyses that indicated a worsening of water quality at the same site. Globally, a relationship was found between MDA increase and 8-oxodGuo formation, in the digestive gland after 7 days of exposure, and later in the gills (21 days). Responses of the digestive glands and gills to the oxidative parameters appeared correlated only after 21 days of exposure. The biomarkers selected confirmed their sensitivity for appraising the water quality of hydrosystems.

Heavy fuel oils containing high levels of polycyclic aromatic hydrocarbons (PAHs) were released into the marine environment after the Erika oil spill on the Atlantic coast. As highly condensed PAH pollutants can bioaccumulate in invertebrates, their transfer to vertebrates through the food chain was of concern. This study aimed to estimate potential genotoxic effects in rats fed for 2 or 4 weeks with the marine mussel Mytilus edulis contaminated by oil pollutants. Two levels of PAH contamination were studied, around 100 and 500 g of total PAHs/kg dry weight (d.w.) in mussels. Genotoxic damage in rats was investigated by single-cell gel electrophoresis (Comet assay) and micronucleus assays in liver, bone marrow, and peripheral blood. DNA damage was observed in the liver of rats fed with the most contaminated mussels (500 g PAHs/kg d.w.).DNA damage also was observed in the bone marrow but less than that in the liver. A small increase in micronuclei frequency was registered as well. This work underlines the bioavailability of pollutants in fuel-oil-contaminated mussels to consumers and the use- fulness of the Comet assay as a sensitive tool in biomonitoring to analyze responses to PAH transfer in food. The occurrence of substituted PAHs and related compounds such as benzothiophenes in addition to nonsubstituted PAHs in fuel oils and mussels raised the question of whether they were implicated in the genotoxic effects registered in rats. © 2004 Wiley Periodicals, Inc. Environ Toxicol 19: 387-395, 2004.

Research on biomarkers as early bioindicators of perturbation in populations and individuals has been gaining ground over the last decade. This ecotoxicological approach relies on the fact that changes occur at low levels of organization before the community is affected and thus they can be monitored to assess environmental safety. Changes may concern behavior, physiology, biochemistry, or genomic structure and functioning, and may impair population dynamics in the long-term.Ecotoxicity studies based on biomarkers allow us to measure the impact of environmental stressors and to easily follow the evolution of the systems towards degradation or restoration. Over and above their use as simple indices of exposure to specific pollutants, biomarkers can give an insight into ecosystem health.The results of our experience in field studies involving ecotoxicologists and ecologists will be presented in order to illustrate the relevance of such an integrating strategy for environmental quality assessment. Keywords: Biomarkers, Bioindicators, Bivalves, Antioxidant systems, Toxicity

International audience; Cerium nanoparticles (nCeO(2)) are widely used in everyday products, as fuel and paint additives. Meanwhile, very few studies on nCeO(2) sublethal effects on aquatic organisms are available. We tried to fill this knowledge gap by investigating short-term effects of nCeO(2) at environmentally realistic concentrations on two freshwater invertebrates; the amphipod Gammarus roeseli and the bivalve Dreissena polymorpha, using an integrated multibiomarker approach to detect early adverse effects of nCeO(2) on organism biology. Differences in the behaviour of the organisms and of nanoparticles in the water column led to differential nCeO(2) bioaccumulations, G. roeseli accumulating more cerium than D. polymorpha. Exposure to nCeO(2) led to decreases in the size of the lysosomal system, catalase activity and lipoperoxidation in mussel digestive glands that could result from nCeO(2) antioxidant properties, but also negatively impacted haemolymph ion concentrations. At the same time, no strong adverse effects of nCeO(2) could be observed on G. roeseli. Further experiments will be necessary to confirm the absence of severe nCeO(2) adverse effects in long-term environmentally realistic conditions.

International audience; In order to provide reliable information about responsiveness of biomarkers during environmental monitoring, there is a need to improve the understanding of inter-population differences. The present study focused on eight populations of zebra mussels and aimed to describe how variable are biomarkers in different sampling locations. Biomarkers were investigated and summarised through the Integrated Biomarker Response (IBR index). Inter-site differences in IBR index were analysed through comparisons with morphological data, proteomic profiles and genetic background of the studied populations. We found that the IBR index was a good tool to inform about the status of sites. It revealed higher stress in more polluted sites than in cleaner ones. It was neither correlated to proteomic profiles nor to genetic background, suggesting a stronger influence of environment than genes. Meanwhile, morphological traits were related to both environment and genetic background influence. Together these results attest the benefit of using biological tools to better illustrate the status of a population and highlight the need of consider inter-population difference in their baselines. (C) 2014 Elsevier B.V. All rights reserved.

International audience; The hazards linked to pharmaceutical residues like antidepressants are currently a major concern of ecotoxicology because they may have adverse effects on non-target aquatic organisms. Our study assesses the ecotoxicity of three antidepressants (fluoxetine, sertraline and clomipramine) using a battery of marine and freshwater species representing different trophic levels, and compares the bioassay sensitivity levels. We selected the following bioassays: the algal growth inhibition test (Skeletonema marinoi and Pseudokirchneriella subcapitata), the microcrustacean immobilization test (Artemia salina and Daphnia magna), development and adult survival tests on Hydra attenuata, embryotoxicity and metamorphosis tests on Crassostrea gigas, and in vitro assays on primary cultures of Haliotis tuberculata hemocytes. The results showed high inter-species variability in EC50-values ranging from 43 to 15,600 µg/L for fluoxetine, from 67 to 4,400 µg/L for sertraline, and from 4.70 µg/L to more than 100,000 µg/L for clomipramine. Algae (S. marinoi and P. subcapitata) and the embryo-larval stages of the oyster C. gigas were the most sensitive taxa. This raises an issue due to their ecological and/or economic importance. The marine crustacean A. salina was the least sensitive species. This difference in sensitivity between bioassays highlights the importance of using a test battery.

International audience; To investigate xenobiotic impacts on organism physiology, several studies involve biomarker assessment. However, most studies do not take into account the toxic effect on both males and females. Here, we have investigated the influence of gender on the detoxification response (reduced glutathione, metal-lothionein, gamma-glutamylcystein ligase and carotenoid), energy reserves (protein, lipids and glycogen) and biomarker of toxic effects (malondialdehyde) in Gammarus roeseli exposed to cadmium. A principal component analysis revealed that G. roeseli males and females were differently impacted by cadmium. We observed lower malondialdehyde levels in females than in males, whatever the condition tested (i.e. control, 2 and 8 mu g Cd L-1), although the pattern of responses of control and exposures to 2 or 8 mu g L-1 was the same for both genders. Results could be linked to apparently more effective detoxification displayed by females than by males. Protein concentrations were unchanged in both genders, lipids contents were always significantly decreased and glycogen contents decreased only in females. This study supports the importance of taking into account the gender in ecotoxicological studies to have an overview of xenobiotics effects on a population.

The study aims at investigating the effects of silver (Ag), a re-emerging contaminant, on physiological and behavioural responses in Gammarus fossarum . In a first experiment, G. fossarum Ag LC50s were evaluated during 96 h under semi-static mode of exposure. Juveniles appeared to be more sensitive to Ag (LC50 96 h : 1.01 μg L −1 ) than ovigerous females (LC50 96 h : 1.9 μg L −1 ) and adult males (LC50 96 h : 2.2 μg L −1 ). In a second experiment, the physiological (osmo-/ionoregulation; antioxidant enzymes; lipid peroxidation (LPO)) and behavioural (locomotor activity and ventilation) responses of male G. fossarum exposed to Ag (0, 0.5, 1, 2, and 4 μg L −1 ) were investigated. The mortality and Ag bioconcentration of gammarids exposed to Ag were significantly higher than controls. Concerning physiological responses, a 48 h-exposure to Ag had no impact on catalase activity but led to a significant decrease of haemolymph osmolality and [Na + ]. On the contrary, LPO, Se-GPx and Na + /K + -ATPase activity were significantly increased. Behavioural responses, such as locomotor and ventilatory activities, were also significantly reduced in Ag exposed gammarids. After 96 h-exposure, especially to 0.5 μg Ag L −1 , most responses (ventilation, locomotor activity, haemolymph osmolality and [Na + ]) were even more pronounced and haemolymph [Cl − ] was significantly decreased but, contrary to observations after 48 h-exposure, Na + /K + -ATPase activity was significantly reduced. Our results demonstrate the drastic effects of realistic [Ag] concentration (0.5 μg Ag L −1 ) on an ubiquitous and functionally important freshwater invertebrate (implied in detritus breakdown), but also strongly suggest an energetic reallocation to the detriment of locomotor activity and in favour of maintenance functions (i.e., osmoregulation and detoxification). These results highlight the risk represented by Ag and the need to perform integrated studies (at different scales, from individual to ecosystem).

International audience; Recent publications on the automated in vitro micronucleus assay show predictive values higher than 85% for the classification of in vitro aneugens, clastogens and non-genotoxic compounds. In the present work, the CHO-k1 micronucleus assay in combination with cellular imaging was further evaluated. Firstly, the effect of a range of S9 concentrations on micronucleus formation and cytotoxicity was investigated. Subsequently, the reproducibility and predictivity of the micronucleus assay on CHO-k1 cells was investigated with a set of four compounds. Then, a larger set of compounds (n=44) was tested on CHO-k1 cells and inter-laboratory correlation was calculated. Finally, cellular imaging was compared with flow cytometry for in vivo assessment of micronucleus formation.The concentration of S9 had a significant impact on micronucleus formation and cytotoxicity. In addition, calculations of relative cell count (RCC) and cytokinesis-block proliferation index (CBPI) showed to be complementary to cytotoxicity assessment. The CHO-k1 micronucleus assay correctly classified the four reference compounds, with a dose-response relationship and low variability. Based on a larger set of compounds, the assay proved to be reliable with a sensitivity of 94% (n = 31) and a specificity of 85% (n = 13). A correlation coefficient of 97% was obtained when the lowest observable adverse effect levels (LOAELs) from our study were compared with those published by Diaz et al. (2007) [10]. In conclusion, the in vitro CHO-k1 micronucleus assay combined with cellular imaging is a predictive assay appropriate for genotoxicity screening at early stages of drug development. In addition, for in vivo assessment of micronucleus formation, we preferred to use flow cytometry rather than cell imaging. (C) 2012 Elsevier B.V. All rights reserved.

International audience; Biological and chemical measurements were performed in mesocosms to investigate the bioavailability of cop-per, with a greater emphasis on the effects of competing ions and copper speciation. Measurements were achieved in three different natural waters for two aquatic species (Gammarus pulex and Fontinalis antipyretica) along a copper gradient concentration: natural concentration, spiked at 5 and 15 μg L −1 . Aquatic mosses exhibited high enrichment rates that were above the background levels compared to gammarids. The accumu-lation of copper in F. antipyretica is better correlated to the weakly complexed copper concentrations measured using differential pulse anodic stripping voltammetry (DPASV) and diffusive gradient in thin film (DGT) than to the free copper concentration measured using an ion selective electrode (ISE). In unspiked natural waters, the presence of dissolved organic ligands strongly controls the metal speciation and consequently largely minimised the impact of competing cations on the accumulation of Cu in mosses. Furthermore, the BioMet Biotic Ligand Model (BLM) successfully describes the site-specific copper bioaccumulation for the freshwater mosses studied. However, the comparison of the results with a previous study appears to indicate that the adsorption/desorption of Cu in mosses is impacted by seasons. This highlights a limit of the BioMet model in which the physiological state of aquatic organisms is not considered. No toxic effect of Cu exposure on lipid peroxidation was observed in the mosses and gammarids regardless of the site and the concentration considered. However, the oxidative stress measured in the mosses via their guaiacol peroxidase (GPX) activity increased in the case where internalised Cu reached maximal values, which suggests a threshold effect on the GPX activity.

As biomarkers are known to be influenced by biotic and abiotic factors (e.g. gender, temperature), we investigated over a one-year long sampling period, the influence of season and gender on reduced glutathione concentrations and its synthesis in the crustacean amphipod Gammarus roeseli. At the same time, we assessed energy reserves and malondialdehyde levels as toxic biomarker. Results have shown that, in both genders, reduced glutathione concentrations were inversely correlated to water temperature, and higher in females than in males whatever the season. Total lipid and glycogen contents were higher in females than in males, allowing females to have enough energy to assume the reproductive period and maintain high GSH concentrations for detoxification processes. Conversely, females have lower cell damages than males. These differences between genders could induce differential sensitivity in a contamination context, and thus affect the population. Females could resist better than males in contaminated environments, especially in spring when reduced glutathione concentration is the highest.

7 pages; International audience; Microsporidia parasites are commonly found in amphipods, where they are often asymptomatic, vertically-transmitted and have several effects on host sexuality and behaviour. As amphipods are often used as models in ecotoxicological studies, we investigated the effect of microsporidian infections on energy reserves and defence capacities of Gammarus roeseli under cadmium stress. Only females were infected by two microsporidia parasites: Dictyocoela roeselum or Dictyocoela muelleri. In physiological conditions, microsporidia had no major effect on energy reserves and defence capacities of G. roeseli, while under cadmium exposure, energy reserves and antioxidant defence were weaker in infected females. Moreover, higher malondialdehyde levels detected in infected females revealed that they suffered more cellular damages. Our results suggest that microsporidia may affect gammarid fitness in stressful conditions, when parasitic stress cannot be compensated by the host. Consequently, microsporidia parasites should be a factor necessary to take into account in ecotoxicology studies involving amphipods.

Biomarker responses in organisms exposed to copper were examined by comparing two gammarid species, Gammarus roeseli and Dikerogammarus villosus, based on gender. G. roeseli specimens were exposed to 20 μg/L of copper for 6, 12, 24 and 48-h periods, while D. villosus were exposed to 20 and 30 μg/L of copper for 12, 48 and 72 h. Males and females of each species were exposed separately and biomarker measurements were performed for each species and gender. The selected biomarkers were antioxidant enzymes as total glutathione peroxidase (GPxtot), selenium-dependent glutathione peroxidase (SeGPx), and catalase activities. Malondialdehyde level (MDA) was measured as a biomarker of toxic effect. Energy reserves were evaluated by means of lipid, glycogen and protein levels. For both species and gender, antioxidant enzyme activities were weakly modified by copper exposure and differences were transient. MDA levels were increased in both species and genders in exposed animals compared to controls, when energy reserves were decreased. G. roeseli was more rapidly overwhelmed by copper toxicity while the first response of D. villosus was the mobilization of its energetic content. D. Villosus probably has specific physiological properties that enable it to cope with copper toxicity and thus become the best competitor.

The relationships between DNA damage and oxidative stress in the digestive gland, gills and haemocytes of the freshwater bivalve Unio tumidus were investigated. Two markers of genotoxicity were measured: DNA breaks by means of the comet assay, and oxidative DNA lesions by means of 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo) measured using high-performance liquid chromatography (HPLC) coupled to electrochemical detection. Lipid peroxidation was evaluated by measuring malondialdehyde (MDA) tissue levels. Effects were studied after exposure of bivalves for 6 days to benzo[a]pyrene (B[a]P) (50 and 100 microg l(-1)) and ferric iron (20 and 40 mg l(-1)), applied alone or in combination. Lipid peroxidation in the digestive gland and gills resulted from exposure to Fe3+ or B[a]P whatever the concentrations tested. DNA oxidatively formed lesions were induced in the two tissues at a higher level after B[a]P exposure than after Fe3+ treatment. No significant dose-response relationship was found with the two compounds and no synergistic effect was observed between Fe3+ and B[a]P. The gills appeared less sensitive than the digestive gland to DNA lesions expressed as 8-oxodGuo and comet results. Good correlations were noted between 8-oxodGuo and comet. MDA and DNA damage did not correlate as well, although it was stronger in the digestive gland than in the gills. Production of mucus by the gills likely served to prevent lesions by reducing the bioavailability of the chemicals tested, which could explain that dose-effect relationships and synergistic effects were not observed.

International audience

In artificial streams (pilot rivers) supplied with the river water of Gave de Pau (France), we studied the effects of methyl methacrylate (MMA) on the autochthonous bivalve Unio tumidus transferred into the streams and on natural freshwater communities colonizing the channels. Unio tumidus and freshwater communities were exposed to MMA for 15 and 30 d, respectively, at measured concentrations ranging from 0.6 to 122 mg/L. Biomarkers studied in the digestive gland and gills of U. tumidus comprised detoxication systems (namely, antioxidant enzyme activities and glutathione status) and lipid peroxidation as a marker of cytotoxicity. Biocoenotic indicators were used to evaluate effects on benthic invertebrates and diatoms. In bivalves, a decrease in antioxidant levels was found at the lowest concentrations tested (0.6 and 6 mg/L), whereas an increase in lipid peroxidation and mortality was registered at 30 mg/L after 15 d of exposure. Disturbances in freshwater communities occurred after 30 d at MMA concentrations of greater than 30 mg/L. Antioxidant responses in bivalves were recorded at the lowest MMA concentration tested, which was close to the predicted no-effect concentration (0.74 mg/L), and cytotoxicity was registered at a concentration corresponding to the 21-d no-observed-effect concentration for Daphnia magna. On the basis of the criteria studied, antioxidant biomarkers of bivalves appeared to be more sensitive than biocoenotic indicators to MMA.

The objective of this work was to evaluate different ecotoxic, cytotoxic and androgenic effects of 14 pharmaceutical compounds: clomipramine, fluoxetine, fluvoxamine, paroxetine, sertraline and venlafaxine, amphotericin B, éconazole, ketoconazole and miconazole, clarithromycin, the acebutolol, gabapentin and cetirizine, using in vivo and in vitro studies. The acute ecotoxicity tests (96h) on the freshwater cnidarian Hydra attenuata showed deleterious effects on adult survival, morphology and embryo development for all tested antidepressants and antifungals drug. The values of EC50 concentrations revealed that econazole, miconazole and sertraline are the most toxic molecules. The chronic ecotoxicity tests on hydras adults (10 days) and embryos (14 days) revealed that most of the molecules tested antidepressants are embryotoxic and teratogenic as they cause malformations in embryos contrary to antifungal which display abnormalities in adults only. These tests also showed that antidepressants tested individually are less toxic than when tested as a mixture. This mixture has a higher toxicity on adults than on embryos, with significant effects concentrations around ng L-1 which are close to measured environmental concentrations. In addition, chronic ecotoxicity results over several generations of hydras have shown identical sensitivity of both first and second generation on morphology of individuals. No more toxicity was observed on the third generation of hydra. Concerning the reproduction of hydras, this parameters was strongly decreased in all generations with an increasing sensitivity of individuals along the generations. Moreover, the mixture of antidepressants affect reproduction of hydras for the second generation at environmental concentrations. In vitro tests conducted on MDA-KB2 cells with the same pharmaceuticals revealed that these compounds tested did not exert any androgenic and cytotoxic effect on cells in culture at environmental concentrations, L’objectif de ce travail a consisté à évaluer différents effets écotoxiques, cytotoxique et le potentiel androgénique de 14 produits pharmaceutiques: la clomipramine, la fluoxétine, la fluvoxamine, la paroxétine, la sertraline et la venlafaxine (antidépresseurs), l’amphotéricine B, l’éconazole, le kétoconazole et le miconazole (antifongiques), la clarithromycine (antibiotique), l’acébutolol (ß-bloquants), le gabapentine (antiépileptiques) et la cétirizine (antihistaminiques), à l’aide d’études in vivo et in vitro. Les tests d’écotoxicité aiguë (96h) sur le cnidaire d’eau douce Hydra attenuata ont montré un effet délétère sur la survie des hydres adultes, la morphologie et le développement des embryons pour l’ensemble d’antidépresseurs et des antifongiques testés. Les valeurs de CE50 calculées ont révélé que l’éconazole, le miconazole et la sertraline sont les molécules les plus toxiques. Les tests d’écotoxicité chronique sur les hydres adultes (10 jours) et les embryons (14 jours) ont mis en évidence que la plus part des molécules d’antidépresseurs testées sont des embryotoxiques et tératogènes puisque ils induisent des malformations chez les embryons contrairement aux antifongiques qui présentent des anomalies seulement chez les adultes. Ces tests ont montré aussi que les molécules d’antidépresseurs testées seules sont moins toxiques que lorsqu’elles sont testées en mélange. En effet, le mélange de molécules antidépresseurs testées présente une toxicité plus élevée sur les adultes que sur les embryons, avec une concentration minimale induisant des effets significatifs de l’ordre de ng L-1, concentrations proches de celles retrouvées dans l’environnement. De plus, les résultats d’écotoxicité chronique sur plusieurs générations d’hydres ont montré que la morphologie des individus de la première génération (F0) ainsi que ceux de la deuxième génération (F1) été affectée de la même manière, démontrant une sensibilité du même ordre vis-à-vis de la sertraline ou du mélange d’antidépresseurs, tandis que les individus issus de la troisième génération (F2) apparaissent moins sensibles lors de l'exposition à la sertraline. Par contre, la reproduction des hydres exposées à la sertraline est diminué de plus en plus dans chaque génération, avec une toxicité plus importante pour les individus de la troisième génération. Le mélange d’antidépresseurs affecte la reproduction des hydres de la deuxième génération F1 à des concentrations environnementales. Les essais in vitro conduits sur les mêmes molécules pharmaceutiques, testées seules et en mélange, sur les cellules MDA-Kb2 n'ont révélé aucun effet androgénique et cytotoxique sur les cellules à des concentrations environnementales

The drug pollution is effective on environmental water compartments. Sewage treatment plants and water purification fail to remove all the molecules present in wastewater and their removal rate varies according to therapeutic classes. Therefore, pharmaceuticals residues are found in human consumption water. The aim of our study is to build a risk assessment to the health of the population who consume water which contain pharmaceuticals residues. As a first time, we identified the nature of the pharmaceutical wastewater contamination and human consumption water. The large number of medicinal products makes it impossible risk assessment for each molecule, we built a hierarchical method for quickly identification of active substance having a higher risk to make a complete sanitary risk assessment for these pharmaceuticals. This part of our work, allowed us to, in first step, identify the criteria to be taken into account for optimizing hierarchy. Then, we could select 12 molecules for which sanitary risk assessment could be implemented. We decided to focus on the quantitative risk assessment of the consumption of polluted water with traces of three cytostatic molecules identified as priorities with our ranking methodology: ifosfamide, cyclophosphamide and 5- FU and a mixture of these three drugs with same concentrations. Toxicity test (Trypan blue, comets assay, micronuclei test) helped us to analyze the dose-response relationship for these molecules. Thus, we could identify the hazardous potential of these substances, assess the dose-response relationship, and analyze occupational and environmental exposure of population to finally calculate the risk. Our sanitary quantitative risk assessment conclusions must be considered with caution given the nature of preliminary data; La pollution médicamenteuse est effective dans les compartiments hydriques de l'environnement. Les stations d'épuration et de potabilisation ne réussissent pas à éliminer la totalité des molécules présentes dans les eaux usées, et leur rendement d'épuration est variable en fonction des familles thérapeutiques. De ce fait, des résidus médicamenteux sont retrouvés dans les eaux destinées à la consommation humaine. C'est pourquoi l'objectif de notre travail était d'évaluer les risques pour la santé des populations qui consomment une eau potentiellement chargée en résidus médicamenteux. Dans un premier temps, nous avons donc identifié la nature de la contamination pharmaceutique des eaux usées et des eaux destinées à la consommation humaine. Le nombre important de spécialités pharmaceutiques présentes rend impossible une analyse successive du risque pour chaque molécule, nous avons construit une méthode de hiérarchisation destinée à identifier rapidement les principes actifs présentant un risque plus important, afin de dérouler prioritairement la méthode complète d'EQRS pour ces produits pharmaceutiques. Cette partie de notre travail a permis d'une part d'identifier les critères à prendre en compte pour une optimisation de la hiérarchisation. Puis, nous avons pu sélectionner 12 molécules pour lesquelles une EQRS pourrait être mise en place. Nous avons décidé de nous focaliser sur l'évaluation quantitative du risque lié à la consommation d'eau polluée par des traces de trois molécules cytostatiques identifiées comme prioritaires lors du déroulé de notre méthodologie de hiérarchisation : l'ifosfamide, le cyclophosphamide et le 5FU ainsi que pour un mélange équi-concentration de ces trois médicaments. Des tests de toxicité (bleu Trypan, comètes, micronoyaux) nous ont aidés à analyser la relation dose-réponse pour ces molécules. Ainsi, nous avons pu identifier le potentiel dangereux de ces substances, évaluer leur relation dose-réponse, puis analyser l'exposition professionnelle et environnementale des populations, pour enfin calculer le risque. Les conclusions de notre EQRS sont à relativiser en raison du caractère préliminaire de nos données

The drug pollution is effective on environmental water compartments. Sewage treatment plants and water purification fail to remove all the molecules present in wastewater and their removal rate varies according to therapeutic classes. Therefore, pharmaceuticals residues are found in human consumption water. The aim of our study is to build a risk assessment to the health of the population who consume water which contain pharmaceuticals residues. As a first time, we identified the nature of the pharmaceutical wastewater contamination and human consumption water. The large number of medicinal products makes it impossible risk assessment for each molecule, we built a hierarchical method for quickly identification of active substance having a higher risk to make a complete sanitary risk assessment for these pharmaceuticals. This part of our work, allowed us to, in first step, identify the criteria to be taken into account for optimizing hierarchy. Then, we could select 12 molecules for which sanitary risk assessment could be implemented. We decided to focus on the quantitative risk assessment of the consumption of polluted water with traces of three cytostatic molecules identified as priorities with our ranking methodology: ifosfamide, cyclophosphamide and 5- FU and a mixture of these three drugs with same concentrations. Toxicity test (Trypan blue, comets assay, micronuclei test) helped us to analyze the dose-response relationship for these molecules. Thus, we could identify the hazardous potential of these substances, assess the dose-response relationship, and analyze occupational and environmental exposure of population to finally calculate the risk. Our sanitary quantitative risk assessment conclusions must be considered with caution given the nature of preliminary data, La pollution médicamenteuse est effective dans les compartiments hydriques de l'environnement. Les stations d'épuration et de potabilisation ne réussissent pas à éliminer la totalité des molécules présentes dans les eaux usées, et leur rendement d'épuration est variable en fonction des familles thérapeutiques. De ce fait, des résidus médicamenteux sont retrouvés dans les eaux destinées à la consommation humaine. C'est pourquoi l'objectif de notre travail était d'évaluer les risques pour la santé des populations qui consomment une eau potentiellement chargée en résidus médicamenteux. Dans un premier temps, nous avons donc identifié la nature de la contamination pharmaceutique des eaux usées et des eaux destinées à la consommation humaine. Le nombre important de spécialités pharmaceutiques présentes rend impossible une analyse successive du risque pour chaque molécule, nous avons construit une méthode de hiérarchisation destinée à identifier rapidement les principes actifs présentant un risque plus important, afin de dérouler prioritairement la méthode complète d'EQRS pour ces produits pharmaceutiques. Cette partie de notre travail a permis d'une part d'identifier les critères à prendre en compte pour une optimisation de la hiérarchisation. Puis, nous avons pu sélectionner 12 molécules pour lesquelles une EQRS pourrait être mise en place. Nous avons décidé de nous focaliser sur l'évaluation quantitative du risque lié à la consommation d'eau polluée par des traces de trois molécules cytostatiques identifiées comme prioritaires lors du déroulé de notre méthodologie de hiérarchisation : l'ifosfamide, le cyclophosphamide et le 5FU ainsi que pour un mélange équi-concentration de ces trois médicaments. Des tests de toxicité (bleu Trypan, comètes, micronoyaux) nous ont aidés à analyser la relation dose-réponse pour ces molécules. Ainsi, nous avons pu identifier le potentiel dangereux de ces substances, évaluer leur relation dose-réponse, puis analyser l'exposition professionnelle et environnementale des populations, pour enfin calculer le risque. Les conclusions de notre EQRS sont à relativiser en raison du caractère préliminaire de nos données

To cope with environmental disturbances, organisms have developed antitoxic defenses commonly used as biomarkers in environmental risk assessment. However, many confounding factors such as temperature and gender could influence biomarker responses. It seems hence necessary to investigate their effects, in order to attribute biological responses only to pollutants. In this context, we investigated the influence of parasitism by studying the acanthocephalan parasite Polymorphus minutus, horizontally transmitted, and microsporidia parasites, vertically transmitted, on the physiological responses of their common host, the freshwater amphipod Gammarus roeseli, a classical model used in ecotoxicology. We investigated the glutathione, a tripeptide having a key role in antitoxic systems, its synthesis (i.e. gamma-glutamylcysteine ligase activity), energy reserves (i.e. lipids, glycogen, proteins) and a toxicity biomarker, the malondialdehyde. The influence of parasitism was considered in different studies: (i) in G. roeseli infected by P. minutus only, (ii) in G. roeseli infected by microsporidia (mainly Dictyocoela roeselum) and (iii) in G. roeseli coinfected by both parasites. Each study was carried out in absence of pollutants and under cadmium stress. We highlighted that, in the absence of contamination, only P. minutus and the co-infection affect the G. roeseli biomarker assessments. After cadmium exposure, the presence of parasites (i.e. single infection or co-infection) influences the mobilization of antitoxic defences, and accentuates toxic effects in their hosts. Our results underline the confounding nature of parasitism in ecotoxicology and thus, highlight the importance to take into account this parameter in the environmental risk assessment, Pour faire face à des perturbations environnementales, les organismes ont développé des défenses antitoxiques couramment utilisés comme biomarqueurs dans l'évaluation de la qualité des milieux. Cependant, de nombreux facteurs confondants comme la température ou le genre, influencent la réponse de ces biomarqueurs. Il est ainsi nécessaire de connaitre les effets de ces facteurs afin d'imputer correctement la réponse biologique mesurée à la présence de polluants. Dans ce contexte, nous avons choisi d'étudier l'influence d'un parasite acanthocéphale, Polymorphus minutus, transmis horizontalement et de microsporidies à transmission verticale, sur les réponses physiologiques de leur hôte, Gammarus roeseli, un crustacé amphipode d'eau douce d'intérêt écotoxicologique. Pour cela, nous avons choisi d'étudier le glutathion, tripeptide jouant un rôle central dans les systèmes antitoxiques, sa synthèse (i.e. activité gamma-glutamylcystéine ligase), les réserves énergétiques (i.e. lipides, glycogène, protéines) et un biomarqueur d'effets toxiques, le malondialdéhyde. L'influence du parasitisme a été appréhendé dans différents cas d'études: (i) chez G. roeseli infecté par P. minutus, (ii) chez G. roeseli infecté par des microsporidies (Dictyocoela roeselum essentiellement) et (iii) chez G. roeseli co-infecté par ces deux types de parasite. Chaque cas d'étude a été réalisé en absence de stress et lors d'une exposition au cadmium. Nous avons mis en évidence qu'en absence de contamination, la présence de P. minutus et une co-infection par P. minutus et D. roeselum affectent les biomarqueurs de G. roeseli. Après exposition au cadmium, la présence de parasites (i.e. infection simple ou co-infection) modifie la mobilisation des défenses antitoxiques et accentue les effets toxiques subits par l'hôte. Les résultats obtenus au cours de ce travail mettent en avant le caractère confondant du parasitisme en écotoxicologie et souligne l'importance de prendre en compte ce paramètre lors de l'évaluation de la qualité des milieux

To cope with environmental disturbances, organisms have developed antitoxic defenses commonly used as biomarkers in environmental risk assessment. However, many confounding factors such as temperature and gender could influence biomarker responses. It seems hence necessary to investigate their effects, in order to attribute biological responses only to pollutants. In this context, we investigated the influence of parasitism by studying the acanthocephalan parasite Polymorphus minutus, horizontally transmitted, and microsporidia parasites, vertically transmitted, on the physiological responses of their common host, the freshwater amphipod Gammarus roeseli, a classical model used in ecotoxicology. We investigated the glutathione, a tripeptide having a key role in antitoxic systems, its synthesis (i.e. gamma-glutamylcysteine ligase activity), energy reserves (i.e. lipids, glycogen, proteins) and a toxicity biomarker, the malondialdehyde. The influence of parasitism was considered in different studies: (i) in G. roeseli infected by P. minutus only, (ii) in G. roeseli infected by microsporidia (mainly Dictyocoela roeselum) and (iii) in G. roeseli coinfected by both parasites. Each study was carried out in absence of pollutants and under cadmium stress. We highlighted that, in the absence of contamination, only P. minutus and the co-infection affect the G. roeseli biomarker assessments. After cadmium exposure, the presence of parasites (i.e. single infection or co-infection) influences the mobilization of antitoxic defences, and accentuates toxic effects in their hosts. Our results underline the confounding nature of parasitism in ecotoxicology and thus, highlight the importance to take into account this parameter in the environmental risk assessment; Pour faire face à des perturbations environnementales, les organismes ont développé des défenses antitoxiques couramment utilisés comme biomarqueurs dans l'évaluation de la qualité des milieux. Cependant, de nombreux facteurs confondants comme la température ou le genre, influencent la réponse de ces biomarqueurs. Il est ainsi nécessaire de connaitre les effets de ces facteurs afin d'imputer correctement la réponse biologique mesurée à la présence de polluants. Dans ce contexte, nous avons choisi d'étudier l'influence d'un parasite acanthocéphale, Polymorphus minutus, transmis horizontalement et de microsporidies à transmission verticale, sur les réponses physiologiques de leur hôte, Gammarus roeseli, un crustacé amphipode d'eau douce d'intérêt écotoxicologique. Pour cela, nous avons choisi d'étudier le glutathion, tripeptide jouant un rôle central dans les systèmes antitoxiques, sa synthèse (i.e. activité gamma-glutamylcystéine ligase), les réserves énergétiques (i.e. lipides, glycogène, protéines) et un biomarqueur d'effets toxiques, le malondialdéhyde. L'influence du parasitisme a été appréhendé dans différents cas d'études: (i) chez G. roeseli infecté par P. minutus, (ii) chez G. roeseli infecté par des microsporidies (Dictyocoela roeselum essentiellement) et (iii) chez G. roeseli co-infecté par ces deux types de parasite. Chaque cas d'étude a été réalisé en absence de stress et lors d'une exposition au cadmium. Nous avons mis en évidence qu'en absence de contamination, la présence de P. minutus et une co-infection par P. minutus et D. roeselum affectent les biomarqueurs de G. roeseli. Après exposition au cadmium, la présence de parasites (i.e. infection simple ou co-infection) modifie la mobilisation des défenses antitoxiques et accentue les effets toxiques subits par l'hôte. Les résultats obtenus au cours de ce travail mettent en avant le caractère confondant du parasitisme en écotoxicologie et souligne l'importance de prendre en compte ce paramètre lors de l'évaluation de la qualité des milieux

The aims of this work was to the study the interest of the single-cell gel electrophoresis (Comet) assay, in environmental genotoxicity. DNA damage were studied in mammals contaminated via the food and in freshwater invertebrates. Studies with the rats demonstrated the occurrence of DNA damage in the livers of the animals fed with mussels strongly contaminated following an oil slick and established a transfer of polycylic aromatic hydrocarbons present in mussels to the consumers. Genotoxic effects were also registered in the bone marrow cells. The results of a study on their reversibility pointed that DNA damages were transitory, with a complete repair in two weeks in our exposure conditions. The second part of this work related genotoxic effects consecutive to in vivo exposures to benzo(a)pyrene and ferric iron in the freshwater bivalve Unio tumidus. For the two markers of genotoxicity, DNA breaks measured by the comet assay and oxidative DNA damage assessed by the measurement of the 8-oxo-7,8-dihydro-2'-deoxyguanosine by HPLC-EC, responses were mainly consecutive to the toxicity of benzo(a)pyrene. DNA breaks did not appear as the most sensitive parameter under these conditions of exposure, comparatively to the measure of DNA oxidation lesions. Globally, the comet assay proved to be adjusted to study the genotoxicity of environmental samples and the biodisponibility of genotoxic compounds., L'objectif général de ce travail était l'étude de l'intérêt du test des comètes en génotoxicité environnementale. Pour cela, nous avons étudié, au moyen de cet essai, les dommages à l'ADN, chez des mammifères contaminés par la voie alimentaire dans un premier temps, puis chez un invertébré d'eau douce, Unio tumidus, suite à des expositions au benzo(a)pyrène et au fer ferrique in vivo, en conditions contr©olées au laboratoire. Les études avec les rats montrent l'apparition de dommages à l'ADN principalement dans le foie, chez les animaux nourris par des moules fortement contaminées suite a une marée noire et permettent d'établir le transfert des polluants présents et des hydrocarbures aromatiques polycycliques, des moules vers le consommateur. Des effets sont également observés à un degré moindre dans les cellules de moelle osseuse. Les résultats d'une étude sur leur réversibilité montrent que les dommages mis en évidence sont transitoires, avec une réparation complète en deux semaines dans tous les cas. Dans la deuxième partie relative à l'étude de deux marqueurs de génotoxicité chez le bivalve Unio tumidus, les réponses observées étaient dues à la toxicité du benzo(a)pyrène. Les cassures de la molécule d'ADN mesurées par le test des comètes ne sont pas apparues comme le paramètre le plus sensible, comparées à la mesure des lésions d'oxydation. Globalement, le test des comètes se révèle adapté à l'étude de la génotoxicité d'échantillons environnementaux et de la biodisponibilité de composés génotoxiques.