Search results for " ecotoxicology"
showing 10 items of 25 documents
Microbial communities as ecological indicators of ecosystem recovery following chemical pollution
2017
International audience; ‘Ecosystem recovery’ is a concept that emerged from the need to preserve our environment against increasing contamination from human activity. However, ecological indicators of ecosystem recovery remain scarce, and it is still difficult to assess recovery of ecological processes at relevant spatial and temporal scales. Microbial communities hold key relevance as indicators of ecosystem recovery as they are ubiquitous among diverse ecosystems, respond rapidly to environmental changes, and support many ecosystem functions and services through taxonomic and functional biodiversity. This chapter summarizes the state-of-the-art in knowledge on the processes driving the st…
Effects of exposure to gadolinium on the development of geographically and phylogenetically distant sea urchins species.
2016
Gadolinium (Gd), a metal of the lanthanide series used as contrast agent for magnetic resonance imaging, is released into the aquatic environment. We investigated the effects of Gd on the development of four sea urchin species: two from Europe, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Exposure to Gd from fertilization resulted in inhibition or alteration of skeleton growth in the plutei. The similar morphological response to Gd in the four species indicates a similar mechanism underlying abnormal skeletogenesis. Sensitivity to Gd greatly varied, with the EC50 ranging from 56 nM to 132 μM across the four species…
TOXICITY INDUCED BY GADOLINIUM IONS ON DEVELOPING SEA URCHIN EMBRYOS
2016
Pharmaceuticals are a class of emerging environmental contaminants. Gadolinium (Gd) is a metal of the lanthanide series of the elements whose chelates are commonly employed as contrast agents for magnetic resonance imaging, and subsequently released into the aquatic environment. We investigated the effects of exposure to sublethal Gd concentrations on the development of four phylogenetically and geographically distant species: two Mediterranean species, Paracentrotus lividus and Arbacia lixula, and two species living in the East coast of Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Measures of the Gd and Ca content inside embryos by ICPMS showed a time- and dose-depend…
Recommendations for ecotoxicity testing with stygobiotic species in the framework of groundwater environmental risk assessment.
2019
As a consequence of the growing global dependence on groundwater resources, environmental risk assessments (ERA) for groundwater are increasingly required and, with that, ecotoxicological studies with groundwater fauna (stygofauna). However, the literature on the ecotoxicological studies with stygobiotic species (i.e. species that complete their life cycle exclusively in groundwater) has not expanded significantly since the first paper published in this field. The limitations regarding the use of stygobiotic species for ecotoxicological testing are clear and consistent across the globe; stygobiotic species are often 1) naturally present in low numbers, 2) difficult to collect, and 3) diffic…
Humusvielas, to mijiedarbība ar augsni veidojošiem komponentiem un humusvielu imobilizācija
2007
Linda Eglīte Humusvielas, to mijiedarbība ar augsni veidojošiem komponentiem un humusvielu imobilizācija Viens no ap mums esošās dabas vides izpētes uzdevumiem ir izprast, kas vidē notiek ar dzīvos organismus veidojošajām vielām. Dabiskas izcelsmes organiskās vielas ir ne tikai dzīvos organismus veidojošās vielas, to metabolīti, bet arī dzīvo organismu sadalīšanās procesu noturīgie produkti. Tie līdz ar to uzskatāmi par nozīmīgu dabas vides sastāvdaļu, kas ietekmē dabā noritošos procesus, kā arī piesārņojošo vielu pārvērtības, tām nonākot apkārtējā vidē. Pēc masas nozīmīgāko daļu no dabiskas izcelsmes organiskajām vielām veido humusvielas. Tās var uzskatīt par visvairāk izplatīto organisko …
Vides apstākļu ietekme uz mikro- un makroelementu saturu pārtikas produktos Latvijā
2014
Bez vitāli svarīgo mikro- un makroelementu ieneses pārtikā no vides (augsnes, ūdens un gaisa) ir iespējams arī barības ķēdes, t. sk., pārtikas piesārņojums ar toksiskiem vai potenciāli toksiskiem elementiem, piemēram, As, Cd, Hg, Pb. Promocijas darba mērķa ietvaros tika veikta Latvijā iegūtu pārtikas produktu paraugu mikro- un makroelementu sastāva kvantitatīvā analīze, lai noskaidrotu vides apstākļu ietekmi uz elementu koncentrāciju un ieneses ceļiem pārtikā. Papildus, lai vērtētu elementu biopieejamību barības ķēdē, tika veikta eksperimentāla pārtikas kultūraugu audzēšana mākslīgi piesārņotā augsnē. Iegūtie dati liecina par vairāku dabiskas un antropogēnas izcelsmes vides apstākļu, piemēr…
Influence of landscape composition and diversity on contaminant flux in terrestrial food webs: a case study of trace metal transfer to European black…
2012
13 pages; International audience; Although understanding the influence of the spatial arrangement of habitats and interacting communities on the processes of pollutant flux and impacts is critical for exposure and risk assessment, to date few studies have been devoted to this emergent topic. We tested the hypothesis that landscape composition and diversity affect the transfer of trace metals to vertebrates. Bioaccumulation of Cd and Pb in blood and feathers of European blackbirds Turdus merula (n=138) was studied over a smelter-impacted area (Northern France). Landscape composition (type and occurrence of the different habitats) and diversity (number of different habitat types and the propo…
Contrasting Effects of Environmental Concentrations of Sulfonamides on Microbial Heterotrophic Activities in Freshwater Sediments
2021
The sulfonamide antibiotics sulfamethoxazole (SMX) and sulfamethazine (SMZ) are regularly detected in surface sediments of contaminated hydrosystems, with maximum concentrations that can reach tens of μg kg–1 in stream and river sediments. Little is known about the resulting effects on the exposed benthic organisms. Here we investigated the functional response of stream sediment microbial communities exposed for 4 weeks to two levels of environmentally relevant concentrations of SMX and SMZ, tested individually. To this end, we developed a laboratory channel experiment where natural stream sediments were immersed in water contaminated with nominal environmental concentrations of 500 and 5,0…
Antibiotrophy: Key Function for Antibiotic-Resistant Bacteria to Colonize Soils—Case of Sulfamethazine-Degrading Microbacterium sp. C448
2021
Chronic and repeated exposure of environmental bacterial communities to anthropogenic antibiotics have recently driven some antibiotic-resistant bacteria to acquire catabolic functions, enabling them to use antibiotics as nutritive sources (antibiotrophy). Antibiotrophy might confer a selective advantage facilitating the implantation and dispersion of antibiotrophs in contaminated environments. A microcosm experiment was conducted to test this hypothesis in an agroecosystem context. The sulfonamide-degrading and resistant bacterium Microbacterium sp. C448 was inoculated in four different soil types with and without added sulfamethazine and/or swine manure. After 1 month of incubation, Micro…
Toxicity induced by Gadolinium ions on sea urchin embryos: comparison among phylogenetically distant species and focus on stress response and skeleto…
2016
Pharmaceuticals are a class of emerging environmental contaminants. Gadolinium (Gd) is a lanthanide metal whose chelates are employed as contrast agents for magnetic resonance imaging, and subsequently released into the aquatic environment. We investigated the effects of exposure to sublethal Gd concentrations on the development of four phylogenetically and geographically distant sea urchin species: two Mediterranean, Paracentrotus lividus and Arbacia lixula, and two from Australia, Heliocidaris tuberculata and Centrostephanus rodgersii. Sensitivity to Gd greatly varied, with EC50 ranging from 56 nM to 132 µM across the four species. Measures of the Gd and Ca content inside embryos showed a…