خيارات البحث
النتائج 371 - 380 من 4,013
Feather mercury concentrations in Southern Ocean seabirds: Variation by species, site and time النص الكامل
2016
Becker, Peter H. | Goutner, Vassilis | Ryan, Peter G. | González-Solís, Jacob
We studied mercury contamination in 25 seabird species breeding along a latitudinal gradient across the Southern Ocean, from Gough Island (40°S) through Marion Island (47°S) to Byers Peninsula (63°S). Total mercury concentrations in body feather samples of adults caught at breeding colonies from 2008 to 2011 were determined. Krill (Euphausia spp.) and other zooplankton consumers had low mercury concentrations (gentoo penguin Pygoscelis papua, chinstrap penguin Pseudomonas Antarctica, common diving petrel Pelecanoides urinatrix, broad-billed prion Pachyptila vittata; mean levels 308–753 ng g−1), whereas seabirds consuming squid or carrion had high mercury concentrations (ascending order: Kerguelen petrel Aphrodroma brevirostris, southern giant petrel Macronectes giganteus, soft-plumaged petrel Pterodroma mollis, sooty albatross Phoebetria fusca, Atlantic petrel Pterodroma incerta, northern giant petrel Macronectes halli, great-winged petrel Pterodroma macroptera; 10,720–28038 ng g−1). The two species with the highest mercury concentrations, northern giant petrels and great-winged petrels, bred at Marion Island. Among species investigated at multiple sites, southern giant petrels had higher mercury levels at Marion than at Gough Island and Byers Peninsula. Mercury levels among Byers Peninsula seabirds were low, in two species even lower than levels measured 10 years before at Bird Island, South Georgia. Replicate measurements after about 25 years at Gough Island showed much higher mercury levels in feathers of sooty albatrosses (by 187%), soft-plumaged petrels (53%) and Atlantic petrels (49%). Concentrations similar to the past were detected in southern giant petrels at Gough and Marion islands, and in northern giant petrels at Marion. There were no clear indications that timing of moult or migratory behavior affected mercury contamination patterns among species. Causes of inter-site or temporal differences in mercury contamination could not be verified due to a lack of long-term data related to species’ diet and trophic levels, which should be collected in future together with data on mercury contamination.
اظهر المزيد [+] اقل [-]Statewide surveillance of halogenated flame retardants in fish in Illinois, USA النص الكامل
2016
Widelka, Margaret | Lydy, Michael J. | Wu, Yan | Chen, Da
In order to better understand the exposure of aquatic systems to halogenated flame retardant contaminants, the present study investigated a variety of legacy and emerging flame retardants in common carp and largemouth bass collected from 58 stations across Illinois (United States). The data revealed that polybrominated diphenyl ethers (PBDEs) generally dominated the flame retardant residues in Illinois fish. Concentrations of ΣPBDEs (including all detectable PBDE congeners) ranged from 24.7 to 8270 ng/g lipid weight (median: 135 ng/g lw) in common carp and 15–3870 ng/g lw (median: 360 ng/g lw) in largemouth bass. In addition to PBDEs, Dechlorane analogues (i.e. Dec-603, Dec-604, and Chlordane Plus) were also frequently detected. Median concentrations of ΣDechloranes (including all detected Dechlorane analogues) were 34.4 and 23.3 ng/g lw in common carp and largemouth bass, respectively. Other emerging flame retardants, including tetrabromo-o-chlorotoluene (TBCT), hexabromobenzene (HBBZ), 2-ethylhexyltetrabromobenzoate (EH-TBB), and bis(2-ethylhexyl)-3,4,5,6-tetrabromo-phthalate (BEH-TEBP), were also detected in 40–78% of the fish at the monitored stations. Spatial analysis revealed significantly greater PBDE concentrations in fish living in impaired urban streams and lakes compared to those from the impaired agricultural and unimpaired agricultural/urban waters, demonstrating a significant urban influence on PBDE contamination. Future studies and environmental monitoring are recommended to focus on temporal trends of PBDEs and alternative flame retardants, as well as human exposure risks via edible fishes, in the identified Areas of Concern within Illinois.
اظهر المزيد [+] اقل [-]Size evolution of ultrafine particles: Differential signatures of normal and episodic events النص الكامل
2016
Joshi, Manish | Khan, Arshad | Anand, S. | Sapra, B.K.
The effect of fireworks on the aerosol number characteristics of atmosphere was studied for an urban mega city. Measurements were made at 50 m height to assess the local changes around the festival days. Apart from the increase in total number concentration and characteristic accumulation mode, short-term increase of ultrafine particle concentration was noted. Total number concentration varies an order of magnitude during the measurement period in which peak occurs at a frequency of approximately one per day. On integral scale, it seems not possible to distinguish an episodic (e.g. firework bursting induced aerosol emission) and a normal (ambient atmospheric changes) event. However these events could be differentiated on the basis of size evolution analysis around number concentration peaks. The results are discussed relative to past studies and inferences are drawn towards aerosol signatures of firework bursting. The short-term burst in ultrafine particle concentration can pose an inhalation hazard.
اظهر المزيد [+] اقل [-]Assessment of biological effects of environmental pollution in Mersin Bay (Turkey, northeastern Mediterranean Sea) using Mullus barbatus and Liza ramada as target organisms النص الكامل
2016
Yılmaz, Doruk | Kalay, Mustafa | Dönmez, Erdem | Yılmaz, Nejat
The increasing emphasis on the assessment and monitoring of marine ecosystems has revealed the need to use appropriate biological indicators for these areas. Enzyme activities and histopathology are increasingly being used as indicators of environmental stress since they provide a definite biological end-point of pollutant exposure. As part of an ecotoxicological assessment of Mersin Bay, EROD enzyme activity and histopathological response in selected organs and tissues of two species of fish, Mullus barbatus (red mullet) and Liza ramada (thinlip grey mullet), captured from area were examined. Pollutant (Organochlorines (OC), alkylphenols (APs) and BPA) levels and biomarker responses in tissue samples were evaluated together for their potential to alter the metabolism and cellular aspects in liver and gonad. Elevated induction of EROD activity and histopathological alterations in contaminated samples from Mersin Bay was observed compared to reference site indicating the exposure to potential pollutants.
اظهر المزيد [+] اقل [-]Covalent triazine-based framework: A promising adsorbent for removal of perfluoroalkyl acids from aqueous solution النص الكامل
2016
Wang, Bingyu | Lee, Linda S. | Wei, Chenhui | Fu, Heyun | Zheng, Shourong | Xu, Zhaoyi | Zhu, Dongqiang
Perfluoroalkyl acids (PFAAs) are highly stable, persistent, and ubiquitous in the environment with significant concerns growing with regards to both human and ecosystem health. Due to the high stability to both biological and chemical attack, the only currently feasible approach for their removal from water is adsorbent technology. The main objective of this study was to assess a covalent triazine-based framework (CTF) adsorbent for removal from aqueous solutions of perfluoro C4, C6, and C8 carboxylates and sulfonates including the two C8s most commonly monitored, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS). Adsorption affinity and capacity were quantified and compared to three commonly used sorbents: pulverized microporous activated carbon, single-walled carbon nanotubes, and Amberlite IRA-400 anion-exchange resin. CTF adsorbent exhibited pronouncedly higher adsorption affinity and capacity of PFAAs than other test sorbents. The remarkably strong adsorption to CTF can be attributed to the favored electrostatic interaction between the protonated triazine groups on the inner wall of the hydrophobic CTF pore and the negatively charged head groups of the PFAAs intercalated between the CTF layers. The homogeneous, nanosized pores (1.2 nm) of CTF hindered adsorption of a large-sized dissolved humic acid, thus minimizing the suppression of PFAA adsorption. Additionally, regeneration of CTF was easily accomplished by simply raising pH > 11, which inhibited the electrostatic adsorptive interaction of PFAAs.
اظهر المزيد [+] اقل [-]Pentachlorophenol from an old henhouse as a dioxin source in eggs and related human exposure النص الكامل
2016
Piskorska-Pliszczynska, Jadwiga | Strucinski, Pawel | Mikolajczyk, Szczepan | Maszewski, Sebastian | Rachubik, Jaroslaw | Pajurek, Marek
High levels of polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) were detected in free-range eggs, and these levels reached a concentration of 29.84 ± 7.45 pg of WHO-TEQ/g of fat. This value exceeded the EU maximum permitted level of 2.5 pg of WHO-TEQ/g of fat for PCDD/F congeners by twelve-fold. A chemical analysis (HRGC-HRMS) revealed elevated amounts of OCDD, OCDF, HxCDD, HpCDD and HpCDF. During the investigation, samples of feed, soil, wall scrapings, wooden ceiling of the henhouse and tissues from laying hens were examined for dioxin contents (30 samples altogether). The long and complicated investigation found that the source of dioxins in the poultry farm was pentachlorophenol-treated wood, which was used as structural components in the 40-year-old farm building adapted to a henhouse. The wooden building material contained PCDD/Fs at a concentration of 3922.60 ± 560.93 pg of WHO-TEQ/g and 11.0 ± 2.8 μg/kg of PCP. The potential risk associated with dioxin intake was characterized by comparing the theoretically calculated weekly and monthly intakes with the toxicological reference values (TRVs), namely the Tolerable Weekly Intake (TWI) and Provisional Tolerable Monthly Intake (PTMI) values of 14 pg of WHO-TEQ/kg of bw and 70 pg of WHO-TEQ/kg of bw, respectively. The intake of dioxins estimated for high egg consumers (approximately 5–6 eggs/week) exceeded the TWI and PTMI values, which may pose a risk of delayed adverse health effects. The estimated dose of PCDD/Fs and DL-PCBs for children consuming 5 eggs per week exceeded the TWI by as much as 450% because of their nearly 5-fold-lower body weight. Although the dioxin intake estimated for the average consumption of eggs in the general population did not exceed any of the TRVs applied (58.7% TWI and 51.1% PTMI), such a situation should be considered unacceptable from a public health perspective because eggs are not the only source of these contaminants.
اظهر المزيد [+] اقل [-]Reliability of stable Pb isotopes to identify Pb sources and verifying biological fractionation of Pb isotopes in goats and chickens النص الكامل
2016
Nakata, Hokuto | Nakayama, Shouta M.M. | Yabe, John | Liazambi, Allan | Mizukawa, Hazuki | Darwish, Wageh Sobhy | Ikenaka, Yoshinori | Ishizuka, Mayumi
Stable Pb isotope ratios (Pb-IRs) have been recognized as an efficient tool for identifying sources. This study carried out at Kabwe mining area, Zambia, to elucidate the presence or absence of Pb isotope fractionation in goat and chicken, to evaluate the reliability of identifying Pb pollution sources via analysis of Pb-IRs, and to assess whether a threshold for blood Pb levels (Pb-B) for biological fractionation was present. The variation of Pb-IRs in goat decreased with an increase in Pb-B and were fixed at certain values close to those of the dominant source of Pb exposure at Pb-B > 5 μg/dL. However, chickens did not show a clear relationship for Pb-IRs against Pb-B, or a fractionation threshold. Given these, the biological fractionation of Pb isotopes should not occur in chickens but in goats, and the threshold for triggering biological fractionation is at around 5 μg/dL of Pb-B in goats.
اظهر المزيد [+] اقل [-]Reconstructing the Chernobyl Nuclear Power Plant (CNPP) accident 30 years after. A unique database of air concentration and deposition measurements over Europe النص الكامل
2016
Evangeliou, Nikolaos | Hamburger, Thomas | Talerko, Nikolai | Zibtsev, Sergey | Bondar, Yuri | Stohl, Andreas | Balkanski, Yves | Mousseau, Timothy A. | Møller, Anders P.
Reconstructing the Chernobyl Nuclear Power Plant (CNPP) accident 30 years after. A unique database of air concentration and deposition measurements over Europe النص الكامل
2016
Evangeliou, Nikolaos | Hamburger, Thomas | Talerko, Nikolai | Zibtsev, Sergey | Bondar, Yuri | Stohl, Andreas | Balkanski, Yves | Mousseau, Timothy A. | Møller, Anders P.
30 years after the Chernobyl Nuclear Power Plant (CNPP) accident, its radioactive releases still remain of great interest mainly due to the long half-lives of many radionuclides emitted. Observations from the terrestrial environment, which hosts radionuclides for many years after initial deposition, are important for health and environmental assessments. Furthermore, such measurements are the basis for validation of atmospheric transport models and can be used for constraining the still not accurately known source terms. However, although the “Atlas of cesium deposition on Europe after the Chernobyl accident” (hereafter referred to as “Atlas”) has been published since 1998, less than 1% of the direct observations of 137Cs deposition has been made publicly available. The remaining ones are neither accessible nor traceable to specific data providers and a large fraction of these data might have been lost entirely. The present paper is an effort to rescue some of the data collected over the years following the CNPP accident and make them publicly available. The database includes surface air activity concentrations and deposition observations for 131I, 134Cs and 137Cs measured and provided by Former Soviet Union authorities the years that followed the accident. Using the same interpolation tool as the official authorities, we have reconstructed a deposition map of 137Cs based on about 3% of the data used to create the Atlas map. The reconstructed deposition map is very similar to the official one, but it has the advantage that it is based exclusively on documented data sources, which are all made available within this publication. In contrast to the official map, our deposition map is therefore reproducible and all underlying data can be used also for other purposes. The efficacy of the database was proved using simulated activity concentrations and deposition of 137Cs from a Langrangian and a Euleurian transport model.
اظهر المزيد [+] اقل [-]Accumulation of polybrominated diphenyl ethers in the brain compared with the levels in other tissues among different vertebrates from an e-waste recycling site النص الكامل
2016
Zhao, Yaxian | Li, Yuanyuan | Qin, Xiaofei | Lou, Qinqin | Qin, Zhanfen
This study aimed to investigate the accumulation of polybrominated diphenyl ethers (PBDEs) in the brain compared with that in other tissues among different vertebrates. We collected mice, chickens, ducks, frogs, and fish from an e-waste recycling region in Taizhou, China, and measured PBDE concentrations in brain, liver and muscle tissues. The levels of PBDE in the tissues of mice, chickens, ducks, frogs and fish ranged 0.45–206, 0.06–18.8, 1.83–112, 2.75–108, and 0.02–32.0 ng/g wet weight, respectively. Preferential distribution in the liver and muscle relative to the brain was observed for PBDEs in mice, chickens, ducks and frogs. However, a high retention in the brain compared to the liver and muscle was observed in fish. Comparison of the brain/liver concentration (B/L) ratios revealed differences in PBDEs accumulation in the brain among these vertebrates. PBDEs accumulation in the brain was greatest in fish, followed by frogs, while the lowest accumulation occurred in the brains of mammals and birds. The findings apparently coincided with the evolution of the blood-brain barrier (BBB) across vertebrates, i.e. the BBB of fish might be less efficient than those of mammals, birds and amphibian. Low brominated congeners (such as BDE-28, BDE-47 and BDE-99) were predominant in the brains of investigated vertebrates, whereas BDE-209 was most abundant in liver and muscle tissues of mice, chickens and ducks. Significant differences in B/L ratios among PBDE congeners were found in both mice and chickens (p < 0.05). Particularly in mice, the B/L ratios of PBDE congeners presented a declining trend with increased bromine number. Our findings suggested that low brominated congeners might have a higher capacity to penetrate the BBB and accumulate in the brain, whereas high brominated congeners such as BDE-209 might have less potency to pass through the barrier. Further experimental studies are needed to confirm our findings.
اظهر المزيد [+] اقل [-]Evaluation of the ecotoxicological impact of the organochlorine chlordecone on soil microbial community structure, abundance, and function النص الكامل
2016
Merlin, Chloé | Devers, Marion | Béguet, Jérémie | Boggio, Baptiste | Rouard, Nadine | Martin-Laurent, Fabrice | Agroécologie [Dijon] ; Institut National de la Recherche Agronomique (INRA)-Université de Bourgogne (UB)-AgroSup Dijon - Institut National Supérieur des Sciences Agronomiques, de l'Alimentation et de l'Environnement | ADEME/Region Bourgogne grant ; "Biodechlord project" - INRA AIP Demichlord part of PNAC 1
International audience | The insecticide chlordecone applied for decades in banana plantations currently contaminates 20,000 ha of arable land in the French West Indies. Although the impact of various pesticides on soil microorganisms has been studied, chlordecone toxicity to the soil microbial community has never been assessed. We investigated in two different soils (sandy loam and silty loam) exposed to different concentrations of CLD (D0, control; D1 and D10, 1 and 10 times the agronomical dose) over different periods of time (3, 7, and 32 days): (i) the fate of chlordecone by measuring C-14-chlordecone mass balance and (ii) the impact of chlordecone on microbial community structure, abundance, and function, using standardized methods (-A-RISA, taxon-specific quantitative PCR (qPCR), and C-14-compounds mineralizing activity). Mineralization of C-14-chlordecone was inferior below 1 % of initial C-14-activity. Less than 2 % of C-14-activity was retrieved from the water-soluble fraction, while most of it remained in the organic-solvent-extractable fraction (75 % of initial C-14-activity). Only 23 % of the remaining C-14-activity was measured in nonextractable fraction. The fate of chlordecone significantly differed between the two soils. The soluble and nonextractable fractions were significantly higher in sandy loam soil than in silty loam soil. All the measured microbiological parameters allowed discriminating statistically the two soils and showed a variation over time. The genetic structure of the bacterial community remained insensitive to chlordecone exposure in silty loam soil. In response to chlordecone exposure, the abundance of Gram-negative bacterial groups (beta-, gamma-Proteobacteria, Planctomycetes, and Bacteroidetes) was significantly modified only in sandy loam soil. The mineralization of C-14-sodium acetate and C-14-2,4-d was insensitive to chlordecone exposure in silty loam soil. However, mineralization of C-14-sodium acetate was significantly reduced in soil microcosms of sandy loam soil exposed to chlordecone as compared to the control (D0). These data show that chlordecone exposure induced changes in microbial community taxonomic composition and function in one of the two soils, suggesting microbial toxicity of this organochlorine.
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