Long-term effects of endocrine disruptors (EDs) on aquatic invertebrates remain difficult to assess, mainly due to the lack of appropriate sensitive toxicity test methods and relevant data analysis procedures. This study aimed at... more
Long-term effects of endocrine disruptors (EDs) on aquatic invertebrates remain difficult to assess, mainly due to the lack of appropriate sensitive toxicity test methods and relevant data analysis procedures. This study aimed at identifying windows of sensitivity to EDs along the life-cycle of the freshwater snail Lymnaea stagnalis, a candidate species for the development of forthcoming test guidelines. Juveniles, sub-adults,
Research Interests: Data Analysis, Ecotoxicology, Reproduction, Statistical Analysis, Risk assessment, and 17 moreAquatic Invertebrates, Biological Sciences, Environmental Sciences, Case Study, Female, Animals, Male, Young Adult, Life Cycle, CHEMICAL SCIENCES, Fresh water, Lymnaea, Risk Assessment, Toxicity Tests, Long Term Effect, Statistical Approach, and Toxicity Testing
The sensitivity of diatom taxonomy and trait-based endpoints to chemicals has been poorly used so far in Environmental Risk Assessment. In this study, diatom assemblages in outdoor flow-through mesocosms were exposed to thiram (35 and... more
The sensitivity of diatom taxonomy and trait-based endpoints to chemicals has been poorly used so far in Environmental Risk Assessment. In this study, diatom assemblages in outdoor flow-through mesocosms were exposed to thiram (35 and 170 μg/L), and a hydrocarbon emulsion (HE; 0.01, 0.4, 2 and 20 mg/L). The effects of exposure were assessed for 12 weeks, including 9 weeks post-treatment, using taxonomic structure and diversity, bioindication indices, biological traits, functional diversity indices, indicator classes and ecological guilds. For both chemicals, diversity increased after the treatment period, and responses of ecological traits were roughly identical with an abundance increase of motile taxa tolerant to organic pollution and decrease of low profile taxa. Bioindication indices were not affected. Traits provided a complementary approach to biomass measurements and taxonomic descriptors, leading to a more comprehensive overview of ecological changes due to organic chemicals...
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Micro- and mesocosms are frequently required in regulatory procedures of aquatic risk assessment for pesticides. However, many questions are still a matter of debate with regard to the use of these systems for environmental risk... more
Micro- and mesocosms are frequently required in regulatory procedures of aquatic risk assessment for pesticides. However, many questions are still a matter of debate with regard to the use of these systems for environmental risk assessment, especially considering the inter-system variability of the measured parameters and its consequences on experimental design and data analysis. In this paper, variability of physico-chemical and biological parameters measured during two long-term experiments (8 to 9 months) in uncontaminated outdoor freshwater lentic mesocosms (8 m3) is analysed. Consequences on the design of ecotoxicity tests in mesocosms and on data analysis are also addressed. Water temperature, pH, dissolved oxygen concentration and concentration of suspended solids exhibited a very low variability whereas nutrient concentrations displayed elevated levels of variability. Among biological parameters, those measured at the individual level were less variable than those measured a...
Research Interests: Data Analysis, Ecotoxicology, Photosynthesis, Invertebrates, Risk assessment, and 23 moreExperimental Design, Phytoplankton, Biological Sciences, Environmental Sciences, Chlorophyll, Female, Animals, Male, Nitrates, Temperature, Water Temperature, Ammonia, Cyprinodontiformes, CHEMICAL SCIENCES, Goldfish, Environmental Risk Assessment, Ecosystem, Oxygen, Fresh water, Dissolved Oxygen, Risk Assessment, Hydrogen-Ion Concentration, and Nitrites
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This study examined the response of 7-ethoxyresorufine-O-deethylase, glutathione-S-transferase, glutathione peroxidase, glutathione content, level of thiobarbituric acid reactive compounds and circulating vitellogenin, in three-spined... more
This study examined the response of 7-ethoxyresorufine-O-deethylase, glutathione-S-transferase, glutathione peroxidase, glutathione content, level of thiobarbituric acid reactive compounds and circulating vitellogenin, in three-spined sticklebacks after 21 days of exposure to Diquat herbicide, commercial nonylphenol polyethoxylate adjuvant and mixture between Diquat and adjuvant. The results showed that adjuvant exerted more important oxidative effects than Diquat and that mixture effects were unlike to single additivity. This study argues for ecotoxicological risk assessment of adjuvants and mixtures of adjuvants and pesticides.
Research Interests: Principal Component Analysis, Risk assessment, Marine And Environmental Pollution, Biological Sciences, Environmental Sciences, and 15 moreFemale, Animals, Male, Glutathione, Glutathione Peroxidase, Nonylphenol, Herbicides, Enzyme, CHEMICAL SCIENCES, Biological markers, Risk Assessment, Glutathione Transferase, Detergents, Environmental Exposure, and Gasterosteus aculeatus
The ecotoxicological impact of nitrate-induced photodegradation products of diuron and chlorotoluron was studied through monospecific biotests conducted in conjunction with experiments in outdoor aquatic mesocosms. Organisms representing... more
The ecotoxicological impact of nitrate-induced photodegradation products of diuron and chlorotoluron was studied through monospecific biotests conducted in conjunction with experiments in outdoor aquatic mesocosms. Organisms representing three trophic levels were used: two heterotrophic microorganisms, the luminescent bacterium Vibrio fischeri and the ciliated protozoa Tetrahymena pyriformis, and one metazoa, the gastropod Lymnaea stagnalis. Among the variety of the phenylurea photoproducts, the N-formylated ones appeared clearly more toxic than the parent compounds towards the microorganisms, whereas the nitroderivatives showed a similar toxicity. Using photodegraded solutions of diuron, toxicity was maintained or even increased during disappearance of the initial herbicide, demonstrating that some of the photoproducts may have an impact additively or in synergy. Enzymatic biomarker assays performed on Lymnaea stagnalis exposed under monospecific conditions showed significant effects, due to the combination of nitrate with the pesticide and its photoproducts. A positive impact on snail fecundity was observed with chlorotoluron both under monospecific laboratory and integrated mesocosm conditions. Oviposition stimulation took place when first- and second-generation photoproducts were predominant.
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Research Interests: Reproduction, Energy Metabolism, Biological Sciences, Environmental Sciences, Animal Feed, and 11 moreAnimals, Chironomidae, Feeding Behavior, CHEMICAL SCIENCES, Larva, Reproducibility of Results, Toxicity Tests, Environmental Toxicology and Chemistry, Silicon Dioxide, Geologic Sediments, and Toxicity Testing
Research Interests: Statistical Analysis, Invertebrates, Risk assessment, Biological Sciences, Insecticides, and 12 moreEnvironmental Sciences, Nitriles, Animals, Plankton, CHEMICAL SCIENCES, Analysis of Variance, Fresh water, Study design, Nutrient Availability, Risk Assessment, Environmental Toxicology and Chemistry, and Environmental
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The influence of tank-mix adjuvants on pesticide toxicity remains largely unknown. Agral 90, a nonylphenol polyethoxylated tank-mix adjuvant, has been used with diquat (bipyridylium herbicide) and fomesafen (diphenyl-ether herbicide) in... more
The influence of tank-mix adjuvants on pesticide toxicity remains largely unknown. Agral 90, a nonylphenol polyethoxylated tank-mix adjuvant, has been used with diquat (bipyridylium herbicide) and fomesafen (diphenyl-ether herbicide) in aquatic indoor microcosms in order to compare the toxicity of the single compounds and of binary herbicide-adjuvant mixtures to Lemna minor. Twenty-four microcosms were used and treatments were performed with substances alone or with herbicide-adjuvant binary mixtures, at two concentrations levels (44.4 and 222.2 microg/L for the herbicides, and 100 and 500 microg/L for Agral 90). Toxicity was assessed weekly for 1 month through growth measurements, as inferred from the relative frond number (RFN) and relative frond area (RFA). Concentrations of diquat and fomesafen in water and sediments were measured weekly. The herbicides showed very different behaviour in microcosms, with a rapid disappearance of diquat from the aqueous phase whereas fomesafen levels remained almost constant over time. Diquat strongly inhibited the growth of L. minor whereas fomesafen had no effect on plant growth. Presence of the adjuvant only slightly reduced the effect of the lowest concentration of diquat, probably as a result of dispersion of the herbicide at the water surface. It is concluded that tank-mix adjuvant designed to improve herbicide efficiency in the terrestrial environment did not have any effect on aquatic plants when applied to the aquatic environment.
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Bacillus thuringiensis var. israelensis (Bti) is commonly used for selective control of larval populations of mosquitoes in coastal wetlands. A two year-study was implemented to investigate whether repeated treatments with Bti applied... more
Bacillus thuringiensis var. israelensis (Bti) is commonly used for selective control of larval populations of mosquitoes in coastal wetlands. A two year-study was implemented to investigate whether repeated treatments with Bti applied either as a liquid (VectoBac® 12AS) or a water-dispersible granule (VectoBac® WG) formulation may affect the abundance and diversity of non-target aquatic invertebrates in saltmarsh pools. Taxonomic composition of the invertebrate communities was typical of brackishwater intermittent ecosystems, with a dominance of annelids, crustaceans and nematocerans. Conditions were contrasted between the two years of the survey, both in terms of annual cumulative rainfall and rainfall distribution throughout the year. As a consequence, the hydroperiod and some other environmental characteristics associated with pool drying played a major role in the dynamics of the invertebrate community. In summer 2006, pool drying reduced the abundance of the polychaete worm Nereis diversicolor, of the amphipod crustacean Corophium volutator and of chironomid larvae. These taxa were able to recolonize rapidly the pools after flooding in September 2006. In 2007, rainfall was more regularly distributed across the year, and the pools did not get dry. Hydrozoans, Chironomini and Orthocladiinae larvae, and oligochaetes were more abundant in treated than in control pools, especially in VectoBac® WG-treated pools. No adverse effects of the treatments were shown on the abundance of N. diversicolor, C. volutator and midge larvae, suggesting that the availability of these food sources for birds was not negatively affected by Bti applications. It is concluded that, as currently performed in Western France coastal wetlands, land-based treatments of saltmarsh pools for larval mosquito control with Bti, used either as VectoBac® 12AS or VectoBac® WG, did not adversely impact non-target aquatic invertebrate communities.
Research Interests: Wetlands, Ecotoxicology, Invertebrates, Biodiversity, France, and 15 moreAquatic Invertebrates, Environmental Sciences, Amphipoda, Bacillus thuringiensis, Negative Affect, Polychaeta, Animals, Chironomidae, Seawater, Mosquito Control, CHEMICAL SCIENCES, Ecosystem, Larva, Coastal Wetlands, and Cumulant
A series of four papers, commissioned by the European Science Foundation, are presented on the state-of-the-art of the use of biomarkers in environmental assessment. These papers are phylogenetically based and cover invertebrates,... more
A series of four papers, commissioned by the European Science Foundation, are presented on the state-of-the-art of the use of biomarkers in environmental assessment. These papers are phylogenetically based and cover invertebrates, vertebrates, plants and invertebrate populations and communities.
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When spiked in sediments, copper is known to reduce growth of Chironomus riparius larvae and the production of eggs by adult females. The aim of this work was to better understand the origin of these phenomena by studying the effects of... more
When spiked in sediments, copper is known to reduce growth of Chironomus riparius larvae and the production of eggs by adult females. The aim of this work was to better understand the origin of these phenomena by studying the effects of copper using developmental and energetic biomarkers, such as changes in larval weight and age and changes in the levels of sugars and lipids. Four-day-old C. riparius larvae were exposed to nominal concentrations of copper of 0, 6.5, 12.5, 25 and 50 mg/kg of dry sediment (silica) in 0.6 l beakers. They were fed ad libitum and exposures were stopped at 7 and 9 days after the beginning of the tests. The larvae were weighed, sexed and aged. For each sex, the larvae belonging to the phases the most frequently found in the beakers were selected for dissection and measurement of energy reserves. The increase in the concentration of copper resulted in an increasing delay in larval growth in both sexes. Desynchronized development was observed, as shown by the increase in the number of individuals that remained in the third instar or early phases of the fourth instar, as well as by a reduction in age of males. Concerning energy reserves, the levels of sugars (glycogen, trehalose and glucose) in the dissected larvae remained almost constant among levels of exposure. In contrast, at the highest copper concentration (50 mg/kg), triglyceride levels suffered a slight reduction whereas the level of free glycerol significantly increased. It is concluded that selection of C. riparius larvae for both sex and age improves the relevance of some energy-yielding substrates as indicators of adverse physiological effects of copper.