2016 |
Larras, F., et al. "Pollution-induced community tolerance (PICT) as a tool for monitoring Lake Geneva long-term in situ ecotoxic restoration from herbicide contamination." Environ Sci Pollut Res. 23.5 (2016): 4301–4311.
Résumé: Chemical monitoring revealed a regular decrease in herbicide concentration in Lake Geneva since last decades that may be linked to an ecotoxic restoration of nontarget phytoplanktonic communities. The Pollution-induced community tolerance (PICT) approach was tested as a tool to monitor the ecotoxic restoration of Lake Geneva for herbicides from 1999 to 2011. We conducted monthly assessments in 1999 and in 2011 for the tolerance of the phytoplankton communities to two herbicides (atrazine and copper), using PICT bioassays. The taxonomical composition of the communities was determined on the same collecting dates. The herbicide concentration decrease during the 12 years significantly influenced the composition of communities. The PICT monitoring indicated that a significant tolerance decrease in the community to both herbicides accompanied the herbicide concentration decrease. PICT measurements for atrazine and copper also changed at the intra-annual level. These variations were mainly due to community composition shifts linked to seasonal phosphorus and temperature changes. PICT monitoring on a seasonal basis is required to monitor the mean tolerance of communities. PICT appeared to be a powerful tool that reflected the toxic effects on environmental communities and to monitor ecotoxic ecosystem restoration.
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Misson, B., et al. "Chemical multi-contamination drives benthic prokaryotic diversity in the anthropized Toulon Bay." Science of The Total Environment. 556 (2016): 319–329.
Résumé: Investigating the impact of human activities on marine coastal ecosystems remains difficult because of the co-occurrence of numerous natural and human-induced gradients. Our aims were (i) to evaluate the links between the chemical environment as a whole and microbial diversity in the benthic compartment, and (ii) to compare the contributions of anthropogenic and natural chemical gradients to microbial diversity shifts. We studied surface sediments from 54 sampling sites in the semi-enclosed Toulon Bay (NW Mediterranean) exposed to high anthropogenic pressure. Previously published chemical data were completed by new measurements, resulting in an in depth geochemical characterization by 29 representative environmental variables. Bacterial and archaeal diversity was assessed by terminal restriction fragment length polymorphism profiling on a selection of samples distributed along chemical gradients. Multivariate statistical analyses explained from 45% to 80% of the spatial variation in microbial diversity, considering only the chemical variables. A selection of trace metals of anthropogenic origin appeared to be strong structural factors for both bacterial and archaeal communities. Bacterial terminal restriction fragment (T-RF) richness correlated strongly with both anthropogenic and natural chemical gradients, whereas archaeal T-RF richness demonstrated fewer links with chemical variables. No significant decrease in diversity was evidenced in relation to chemical contamination, suggesting a high adaptive potential of benthic microbial communities in Toulon Bay.
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2015 |
Louati, H., et al. "Responses of a free-living benthic marine nematode community to bioremediation of a PAH mixture." Environ Sci Pollut Res. 22.20 (2015): 15307–15318.
Résumé: The objectives of this study were (1) to assess the responses of benthic nematodes to a polycyclic aromatic hydrocarbon (PAH) contamination and (2) to test bioremediation techniques for their efficiency in PAH degradation and their effects on nematodes. Sediments with their natural nematofauna communities from Bizerte lagoon (Tunisia) were subjected to a PAH mixture (100 ppm) of phenanthrene, fluoranthene, and pyrene during 30 days. Nematode abundance and diversity significantly decreased, and the taxonomic structure was altered. Results from multivariate analyses of the species abundance data revealed that PAH treatments were significantly different from the control. Spirinia parasitifera became the dominant species (70 % relative abundance) and appeared to be an “opportunistic” species to PAH contamination while Oncholaimus campylocercoides and Neochromadora peocilosoma were strongly inhibited. Biostimulation (addition of mineral salt medium) and bioaugmentation (inoculation of a hydrocarbonoclastic bacterium) were used as bioremediation techniques. Bioremediation treatments enhanced degradation of all three PAHs, with up to 96 % degradation for phenanthrene resulting in a significant stimulation of nematode abundance relative to control microcosms. Nevertheless, these treatments, especially the biostimulation provoked a weak impact on the community structure and diversity index relative to the control microcosms suggesting their feasibility in biorestoration of contaminated sediments.
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Said, O. B., et al. "Changes of benthic bacteria and meiofauna assemblages during bio-treatments of anthracene-contaminated sediments from Bizerta lagoon (Tunisia)." Environ Sci Pollut Res. 22.20 (2015): 15319–15331.
Résumé: Sediments from Bizerta lagoon were used in an experimental microcosm setup involving three scenarios for the bioremediation of anthracene-polluted sediments, namely bioaugmentation, biostimulation, and a combination of both bioaugmentation and biostimulation. In order to investigate the effect of the biotreatments on the benthic biosphere, 16S rRNA gene-based T-RFLP bacterial community structure and the abundance and diversity of the meiofauna were determined throughout the experiment period. Addition of fresh anthracene drastically reduced the benthic bacterial and meiofaunal abundances. The treatment combining biostimulation and bioaugmentation was most efficient in eliminating anthracene, resulting in a less toxic sedimentary environment, which restored meiofaunal abundance and diversity. Furthermore, canonical correspondence analysis showed that the biostimulation treatment promoted a bacterial community favorable to the development of nematodes while the treatment combining biostimulation and bioaugmentation resulted in a bacterial community that advantaged the development of the other meiofauna taxa (copepods, oligochaetes, polychaetes, and other) restoring thus the meiofaunal structure. The results highlight the importance to take into account the bacteria/meiofauna interactions during the implementation of bioremediation treatment.
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2014 |
Minguez, L., et al. "Acute toxicity of 8 antidepressants: What are their modes of action?" Chemosphere. 108 (2014): 314–319.
Résumé: Currently, the hazard posed by pharmaceutical residues is a major concern of ecotoxicology. Most of the antidepressants belong to a family named the Cationic Amphipathic Drugs known to have specific interactions with cell membranes. The present study assessed the impact of eight antidepressants belonging to selective serotonin reuptake inhibitors or serotonin norepinephrine reuptake inhibitors by the combination of multi-approaches (in vivo, in vitro, in silico) and gives some insights on the mode of action for these molecules. Antidepressants were from the most to the least toxic compound for Daphnia magna: Sertraline (EC50 = 1.15 mg L-1) > Clomipramine (2.74 mg L-1)> Amitriptyline (4.82 mg L-1)> Fluoxetine (5.91 mg L-1) > Paroxetine (6.24 mg L-1) > Mianserine (7.81 mg L-1) > Citalopram (30.14 mg L-1) and Venlafaxine (141.28 mg L-1). These acute toxicities were found correlated to Log K, coefficients (R = 0.93, p < 0.001) and to cytotoxicity assessed on abalone hemocytes through the neutral red uptake assay (R = 0.96, p < 0.001). If narcosis as mode of action is typically expected during acute ecotoxicity bioassays, we showed by molecular modeling that particular interactions can exist between antidepressants and phosphatidylcholine, a major component of cell membranes, leading to a more specific mode of action corresponding to a potential acidic hydrolysis of ester functions. (C) 2014 Elsevier Ltd. All rights reserved.
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