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结果 1401-1410 的 4,042
Variability in antioxidant/detoxification enzymes of Sinonovacula constricta exposed to benzo[a]pyrene and phenanthrene 全文
2016
Li, Lei | Jiang, Mei | Shen, Xinqiang
The purpose of this study was to investigate the toxic effects induced by benzo[a]pyrene and phenanthrene. For this purpose, a study was performed on the clam exposed to 0.0, 0.5, 4.5μgL−1 B(a)P and PHE for 15days using parameters of antioxidant defenses and oxidative stress. Antioxidant biomarkers including ethoxyresorufin-O-deethylase, glutathione S-transferase, superoxide dismutase, and glutathione and rylhydrocarbon hydroxylasein gills of Sinonovacula constricta, were analyzed after a 1-, 3-, 9- and 15-day exposure to seawater containing B(a)P and PHE. Integrated biomarker response was calculated by combining multiple biomarkers into a single value. The results showed that the activity of all antioxidant biomarkers was induced throughout the exposure period, and different patterns of variations were detected with exposure time. In addition, the study showed that the two concentrations used caused the activation of different general detoxification mechanisms, and the same concentration at different two PAH compounds induced different toxicity responses.
显示更多 [+] 显示较少 [-]Environmental implications of the use of sulfidic back-bay sediments for dune reconstruction — Lessons learned post Hurricane Sandy 全文
2016
Plumlee, Geoffrey S. | Benzel, William M. | Hoefen, Todd M. | Hageman, Philip L. | Morman, Suzette A. | Reilly, Timothy J. | Adams, Monique | Berry, Cyrus J. | Fischer, Jeffrey M. | Fisher, Irene
Some barrier-island dunes damaged or destroyed by Hurricane Sandy's storm surges in October 2012 have been reconstructed using sediments dredged from back bays. These sand-, clay-, and iron sulfide-rich sediments were used to make berm-like cores for the reconstructed dunes, which were then covered by beach sand. In November 2013, we sampled and analyzed partially weathered materials collected from the cores of reconstructed dunes. There are generally low levels of metal toxicants in the reconstructed dune materials. However oxidation of reactive iron sulfides by percolating rainwater produces acid-sulfate pore waters, which evaporate during dry periods to produce efflorescent gypsum and sodium jarosite salts. The results suggest use of sulfidic sediments in dune reconstruction has both drawbacks (e.g., potential to generate acid runoff from dune cores following rainfall, enhanced corrosion of steel bulwarks) and possible benefits (e.g., efflorescent salts may enhance structural integrity).
显示更多 [+] 显示较少 [-]Environmental availability of potentially toxic elements in estuarine sediments of the Cananéia–Iguape coastal system, Southeastern Brazil 全文
2016
Tramonte, Keila Modesto | Figueira, Rubens Cesar Lopes | de Lima Ferreira, Paulo Alves | Ribeiro, Andreza Portella | Batista, Miriam Fernanda | Mahiques, Michel Michaelovitch de
The Cananéia–Iguape system is located in a Southeastern Brazilian coastal region, acknowledged by UNESCO as Biosphere Reserve of the Atlantic Rainforest. This system underwent important environmental changes due to the opening of the artificial channel of Valo Grande and by past intensive Pb ore mining activities. In view of this scenario, this study evaluated Cu, Pb and Zn availability in sediments from Cananéia–Iguape system, based on the content associated with the main components of the sediments. Moreover, in order to assess local contamination, the metals' contents were compared to Canadian quality guidelines, the past levels of metals preceding the mining activities and background sediment values. Concerning Cu and Zn in a state of chemical remobilization, both elements would possibly present no harm to the local communities. However, Pb available content exceeded the comparison values in various sampling sites, suggesting the need of monitoring regarding its bioavailability.
显示更多 [+] 显示较少 [-]Assessing of surface-ozone concentration in Bucharest, Romania, using OML and satellite data 全文
2016
Grigoraş, Georgiana | Ştefan, Sabina | Rada, Constantin | Grigoraş, Cristinel
The aim of the paper is to assess the spatial distribution of surface-ozone concentrations for Bucharest urban agglomeration by running OML (“Operationelle Meteorologiske Luftkvalitetsmodeller” – Operational Meteorological Air Quality Model) dispersion model. Two data sets from 2009 were used to initialize the model for: (i) air quality data base of the National Network of Air Quality Monitoring (NNAQM); (ii) satellite data obtained from OMI (Ozone Monitoring Instrument) on board of AURA satellite. The potential of satellite data used in air quality assessment in lower troposphere, at local scale was also tested by comparison to data from air-quality monitoring stations. The intercomparison of simulated and measured data emphasized that satellite data can be used for assessment of air quality.
显示更多 [+] 显示较少 [-]Trace Elements in Soils around Coal Mines: Current Scenario, Impact and Available Techniques for Management 全文
2016
Sahoo, Prafulla Kumar | Equeenuddin, Sk. Md | Powell, M. A.
The present paper reviewed the average concentrations of trace elements in soils near coal mine areas from various cities/countries to provide a current global summary of this issue. The contamination of soils was assessed by using global reference materials and various contamination indices. The results show that the average concentrations of trace elements varied widely: As (0.5–38.3 mg/kg), Mn (86–3,700 mg/kg), Zn (1.5–296 mg/kg), Cu (0.5–110 mg/kg), Cr (17.5–954 mg/kg), Ni (4.3–390 mg/kg), Pb (0.5–433 mg/kg), Cd (0.02–4.48 mg/kg), and Hg (0.02–0.69 mg/kg). Most of these values are higher than the average world background soils and upper continental crust (UCC). The geo-accumulation (I gₑₒ) and contamination factor (CF) indices show that the contamination levels of Ni and Pb are higher than other elements. The potential ecological risk index (E ᵢ) suggests a high risk from Cd, especially in the Tabagi River watershed in Brazil and Ledo coal mines in India, and Hg, especially in Oltu (Turkey). The degree of contamination index (C d) reveals that the soils from Barapukuria (Bangladesh), Ledo (India), Ptolemais-Amynteon (Greece), and the Tibagi River (Brazil) have a higher degree of contamination than other sites. To control soil contamination, effective monitoring and legislative measures must be taken immediately. For the long term, various physical, chemical, and biological methods should be implemented. Although the selection of suitable methods is site-specific based on the extent and nature of contamination, in general, phytoremediation seems to be more beneficial and cost-effective than physical/chemical techniques.
显示更多 [+] 显示较少 [-]Manganese Removal from Drinking Water Sources 全文
2016
Tobiason, John E. | Bazilio, Arianne | Goodwill, Joseph | Mai, Xuyen | Nguyen, Chuyen
Manganese (Mn) in drinking water can cause aesthetic and operational problems. Mn removal is necessary and often has major implications for treatment train design. This review provides an introduction to Mn occurrence and summarizes historic and recent research on removal mechanisms practiced in drinking water treatment. Manganese is removed by physical, chemical, and biological processes or by a combination of these methods. Although physical and chemical removal processes have been studied for decades, knowledge gaps still exist. The discovery of undesirable by-products when certain oxidants are used in treatment has impacted physical–chemical Mn removal methods. Understanding of the microorganisms present in systems that practice biological Mn removal has increased in the last decade as molecular methods have become more sophisticated, resulting in increasing use of biofiltration for Mn removal. The choice of Mn removal method is very much impacted by overall water chemistry and co-contaminants and must be integrated into the overall water treatment facility design and operation.
显示更多 [+] 显示较少 [-]Sediment characteristics and benthic ecological status in contrasting marine environments of subtropical Hong Kong 全文
2016
Chan, Alice K.Y. | Xu, Wen-Zhe | Liu, Xiao-Shou | Cheung, Siu Gin | Shin, Paul K.S.
Sediment characteristics and benthic communities on a finer sampling scale in four contrasting environments in subtropical Hong Kong were analyzed in summer and winter 2012. In two harbour habitats which suffered from historic sewage pollution or hypoxic events, organic carbon, nutrient and trace metal content in the sediment were significantly higher than that in an offshore area and a marine reserve. The relatively low organic and nutrient content in the offshore habitat could be resulted from enhanced resuspension of such materials from the seabed owing to intense water mixing and disturbance caused by bottom trawling. The biotic indices AMBI and M-AMBI were shown to be useful in assessing the benthic ecological status of these habitats. Such indices can also be more sensitive than sediment physico-chemical parameters in differentiating the response of macrofauna to seasonal changes in the benthic environment.
显示更多 [+] 显示较少 [-]Perfluoroalkylated substances (PFASs) and legacy persistent organic pollutants (POPs) in halibut and shrimp from coastal areas in the far north of Norway: Small survey of important dietary foodstuffs for coastal communities 全文
2016
Carlsson, Pernilla | Crosse, John D. | Halsall, Crispin | Evenset, Anita | Heimstad, Eldbjørg S. | Harju, Mikael
Halibut (Hippoglossus hippoglossus) and shrimps (Pandalus borealis) are regular foodstuffs for communities in northern Norway and important species for the coastal fishing industry. This is the first study to present a comprehensive overview of the contaminant status of these species, with emphasis on unregulated perfluoroalkylated substances (PFAS). The contaminant concentrations were low and within tolerable levels for human dietary exposure. Median Σpolychlorinated biphenyls (PCB) were 4.9 and 2.5ng/g ww for halibut and unpeeled shrimps, respectively. Concentrations of perfluorooctane sulfonate (PFOS) – the most abundant PFASs – were 0.9 and 2.7ng/g ww in halibut and shrimp, respectively. The halibut fillets were dominated by PCBs, which contributed to 50% of the total POPs load, followed by ΣDDTs; 26% and PFASs (18%), whereas shrimps were dominated by PFASs (74%). ΣPBDEs (polybrominated diphenyl ethers) contributed to 1–4% of the total POP load. Local sources are not contributing significantly to the contaminant burden in these species.
显示更多 [+] 显示较少 [-]Levels, distributions and sources of veterinary antibiotics in the sediments of the Bohai Sea in China and surrounding estuaries 全文
2016
Liu, Xinghua | Zhang, Haibo | Li, Lianzhen | Fu, Chuancheng | Du, Zhen | Huang, Yujuan | Wu, Longhua | Tang, Jianhui | Luo, Yongming | Christie, Peter
Veterinary antibiotics are emerging contaminants of concern. A total of 139 samples comprising 104 marine sediments and 35 estuarine sediments were collected from the Bohai Sea area and analyzed for seventeen antibiotics. The results reveal that the presence and concentration of antibiotics were generally higher in the estuaries than in the sea. The highest antibiotic concentration, 4695μgkg−1 of oxytetracycline, occurred in the estuarine sediment from Ziya New River. Bohai Bay and Laizhou Bay and the surrounding estuaries had higher concentrations of antibiotics. However, low levels of antibiotics detected were detected in Liaodong Bay in contrast to the high concentrations present in the surrounding estuaries. Spatial heterogeneity and principal component analysis suggest a large impact of terrestrial sources of the antibiotics contaminating the Bohai Sea. Risk quotients indicate that current levels of norfloxacin and oxytetracycline might be potentially hazardous to sensitive biota both in the Bohai Sea and in its surrounding estuaries.
显示更多 [+] 显示较少 [-]Development of a short-term chronic toxicity test with a tropical mysid 全文
2016
Figuerêdo, Lívia Pitombeira de | Nilin, Jeamylle | Silva, Allyson Queiroz da | Loureiro, Susana | Costa-Lotufo, Letícia Veras
There is an increasing need to develop reliable methodologies for chronic toxicity testing using tropical species. The present work aimed at developing a suitable short-term chronic toxicity test with Mysidopsis juniae using zinc (Zn) and nickel (Ni) as model chemicals and growth (length and dry weight), survival, and egg production (number of females with eggs) as endpoints after seven days of exposure. Survival and growth of newborn M. juniae were affected by chronic exposure to zinc, while nickel affected only survival. For zinc, dry weight was the most sensitive endpoint with significant effects even at the lowest tested concentration (75μgZn·L−1), whereas for nickel, survival was the most sensitive parameter (LC20 of 26μgNi·L−1). Egg production was not affected. M. juniae short-term chronic testing is a sensitive approach to evaluating metal toxicity; further studies are necessary to assess chronic toxicity for others contaminants in the proposed assay.
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