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Aerobic denitrification and biomineralization by a novel heterotrophic bacterium, Acinetobacter sp. H36 Texte intégral
2017
Su, Jun feng | Shi, Jing xin | Ma, Fang
A novel aerobic denitrification and biomineralization strain H36 was isolated from the Qu Jiang artificial lake. Based on phylogenetic characteristics, the isolated strain was identified as Acinetobacter species. Strain H36 was confirmed to have the ability to perform simultaneous denitrification and biomineralization. Results showed the strain H36 had the capability to completely reduce 96.29% of NO3−–N and 78.59% of Ca2+ over 112h under aerobic condition. Response surface methodology (RSM) analysis demonstrated the highest removal ratio of Ca2+ was 74.24% with hardness concentration of 350mg/L, pH of 8.5, organic concentration of 0.75g/L and inoculum size of 15%. The highest removal ratio of nitrate was 77.00% with hardness concentration of 350mg/L, pH of 7.5, organic concentration of 0.75g/L and inoculum size of 10%. Besides, X-ray diffraction (XRD) analysis showed calcium carbonate could be formed in the process of biomineralization.
Afficher plus [+] Moins [-]Quality index of the surface water of Amazonian rivers in industrial areas in Pará, Brazil Texte intégral
2017
Medeiros, Adaelson Campelo | Faial, Kleber Raimundo Freitas | do Carmo Freitas Faial, Kelson | da Silva Lopes, Iris Danielly | de Oliveira Lima, Marcelo | Guimarães, Raphael Mendonça | Mendonça, Neyson Martins
In this study was to evaluate the waters quality of the Murucupi River, located in urban agglomerate area and intense industrial activity in Barcarena City, Pará State. The Arapiranga River in Abaetetuba City was used as control area (Background), next to Barcarena. Was used the Water Quality Index (WQI) based on nine variables analized. Waters quality of the Arapiranga and Murucupi rivers were regular to good and bad to good, respectively. Anthropogenic influence on the Murucupi River was higher, mainly by the disposal of domestic effluents from the urban agglomerate and of the industrial waste tailing basins upstream of this river. Due to its less inhabited environment and further away from the area urban and industrial, the Arapiranga River was more preserved. Waters pollution of around these area is increasingly intense, and restricted its uses for various purposes.
Afficher plus [+] Moins [-]Spatial and temporal analysis of the risks posed by total petroleum hydrocarbon and trace element contaminants in coastal waters of Kuwait Texte intégral
2017
Nicolaus, E.E.M. | Wright, S.R. | Barry, J. | Bolam, T.P.C. | Ghareeb, K. | Ghaloom, M. | Al-Kanderi, N. | Harley, B.F.M. | Le Quesne, W.J.F. | Devlin, M.J. | Lyons, B.P.
Nine trace elements including As, Cd, Cu, Fe, Hg, Ni, Pb, V and Zn, and total petroleum hydrocarbons were analysed from water samples collected from 23 stations since 1984 from Kuwaiti coastal waters. Here it was investigated whether concentrations of these determinants are at levels above Kuwaiti and internationally established assessment criteria (AC). The results indicate that Cu and Cd had the most Kuwaiti AC breaches over time. Comparing the data of the last sampled year to the least stringent international AC, then Cu and Cd showed breaches at all stations. The trends for trace metals are significantly downwards, especially for Cd and Hg. No determinant measured showed a significant upward trend, indicating that water pollution for these contaminants is not a worsening situation. However, further sampling should be carried out to confirm these findings, especially at shoreline locations, where routine monitoring ceased in 2011 to investigate any recent changes.
Afficher plus [+] Moins [-]Size and dynamics of microplastic in gastrointestinal tracts of Northern Fulmars (Fulmarus glacialis) and Sooty Shearwaters (Ardenna grisea) Texte intégral
2017
Terepocki, Alicia K. | Brush, Alex T. | Kleine, Lydia U. | Shugart, Gary W. | Hodum, Peter
We found microplastic in 89.5% of 143 Northern Fulmars from 2008 to 2013 and 64% of 25 Sooty Shearwaters in 2011–2012 that were found dead or stranded on Oregon and Washington beaches. Average plastic loads were 19.5 pieces and 0.461g for fulmars and 13.3 pieces and 0.335g for shearwaters. Pre-manufactured plastic pellets accounted for 8.5% of fulmar and 33% of shearwater plastic pieces. In both species, plastic in proventriculi averaged 2–3mm larger in greatest dimension than in ventriculi. Intestinal plastic in fulmars averaged 1mm less in greatest dimension than ventricular plastic. There was no significant reduction in pieces or mass of plastic in 33 fulmars held for a median of seven days in a plastic-free environment. Three fulmars that survived to be released from rehabilitation regurgitated plastic, which provided an alternative outlet for elimination of plastic and requires reassessment of the dynamics of plastic in seabird gastrointestinal tracts.
Afficher plus [+] Moins [-]Temporal variations in physiological responses of Kandelia obovata seedlings exposed to multiple heavy metals Texte intégral
2017
Cheng, Shanshan | Tam, Nora Fung Yee | Li, Ruili | Shen, Xiaoxue | Niu, Zhiyuan | Chai, Minwei | Qiu, Guo Yu
A study was conducted to quantify temporal variations in physiological responses of Kandelia obovata under multiple heavy metal stress. The results showed that plant growth was not significantly affected by multiple heavy metal stress during the 120-days experiment. At the start, levels of net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (Tr) showed effects of “low-promotion, high-inhibition”, but Pn and Gs reduced with increasing heavy metal stress at the end. Temporary lipid oxidation was shown by high levels of malondialdehyde (MDA) under high heavy metal stress at the start but was unaffected at the end of the experiment. MDA negatively correlated with biomass and photosynthetic parameters and acted as a sensitive indicator. Proline also shared similar trend and indicated its temporary role in osmotic adjustment. Negative correlations between osmotic adjustment matter and photosynthetic parameters further confirmed the significant role of osmotic adjustment under heavy metal stress.
Afficher plus [+] Moins [-]Relative sensitivity of Arctic species to physically and chemically dispersed oil determined from three hydrocarbon measures of aquatic toxicity Texte intégral
2017
Bejarano, Adriana C. | Gardiner, William W. | Barron, Mace G. | Word, Jack Q.
The risks to Arctic species from oil releases is a global concern, but their sensitivity to chemically dispersed oil has not been assessed using a curated and standardized dataset from spiked declining tests. Species sensitivity to dispersed oil was determined by their position within species sensitivity distributions (SSDs) using three measures of hydrocarbon toxicity: total petroleum hydrocarbons (TPH), polycyclic aromatic hydrocarbon (PAHs), and naphthalenes. Comparisons of SSDs with Arctic/sub-Arctic versus non-Arctic species, and across SSDs of compositionally similar oils, showed that Arctic and non-Arctic species have comparable sensitivities even with the variability introduced by combining data across studies and oils. Regardless of hydrocarbon measure, hazard concentrations across SSDs were protective of sensitive Arctic species. While the sensitivities of Arctic species to oil exposures resemble those of commonly tested species, PAH-based toxicity data are needed for a greater species diversity including sensitive Arctic species.
Afficher plus [+] Moins [-]Adsorption of 17 α-ethyl estradiol with the competition of bisphenol A on the marine sediment of Hong Kong Texte intégral
2017
Fei, Ying-heng | Leung, Kenneth M.Y. | Li, Xiao-yan
The present experimental study was to characterize the adsorption behavior of 17 α-ethyl estradiol (EE2) onto marine sediment in both the single and binary solute systems. Stepwise spiking was innovatively performed to better understand the competition effects. Adsorption of EE2 on the marine sediment can be well fitted by the Freundlich model with an affinity coefficient (KF) varying from 15.8 to 39.8L/kg. It was significantly influenced by SOM and the particle properties. Co-presence of BPA brought about a significant competition effect on the adsorption of EE2, leading to a reduced EE2 adsorption. The competitive effect imposed by EE2 to BPA, however, was even more serious owing probably to the large molecular structure and high hydrophobicity of EE2. The sediment sample with the highest SOM and SSA presented a mild competition effect, while the sediment with the lowest SOM and largest particle size exhibited the most serious competition effect.
Afficher plus [+] Moins [-]Distributions of nitrated polycyclic aromatic hydrocarbons in the sediment of Osaka Bay, Japan Texte intégral
2017
Uno, Seiichi | Tanaka, Hiroyuki | Kokushi, Emiko | Bacolod, Eugene T. | Koyama, Jiro
The distributions of 15 nitrated polycyclic aromatic hydrocarbons (NPAHs) in sediments collected at 44 sites throughout Osaka Bay, Japan were examined. The highest total NPAHs, with a concentration of 1949ng/kg dry weight, were detected near the city of Amagasaki. Some sites near the cities of Osaka, Kishiwada, sand Sakai registered ng/kg levels of NPAHs, but individual NPAH concentrations were relatively lower than those in previous studies. The sources were estimated using principal component analysis, and NPAHs were derived from exhaust gases of automobiles and industries at some sites. However, our results suggest that it is difficult to estimate the source, especially in coastal areas near big cities and large industrial areas, because the generation pathways between parent polycyclic aromatic hydrocarbons (PAHs) and nitrated PAHs are slightly different, and the ratio of PAHs and NPAHs could not be accurately reflect the characters of sources in sediments especially at coastal areas with large-scale industrial zones.
Afficher plus [+] Moins [-]Distribution and enrichment of trace metals in surface marine sediments in the Gulf of Pozzuoli and off the coast of the brownfield metallurgical site of Ilva of Bagnoli (Campania, Italy) Texte intégral
2017
Trifuoggi, Marco | Donadio, Carlo | Mangoni, Olga | Ferrara, Luciano | Bolinesi, Francesco | Nastro, Rosa Anna | Stanislao, Corrado | Toscanesi, Maria | Di Natale, Gabriella | Arienzo, Michele
The distribution of metals in surface sediments of Gulf of Pozzuoli (GoP), embedding the former second Italian largest integrated steelworks of Bagnoli, was studied based on sediment dispersal, quality guidelines (SQGs) and quantitative pollution indices of the respective metals. As, Cd, Hg, Pb, Zn largely exceeded the limits. Hg had a mean of 5.8mg/kg, twentyfold higher the rule, accumulating primarily near Bagnoli site. The mean effective range quotient, m-ERM-Q, revealed a high potential for negative biological effects especially in the area nearby the Bagnoli site. The enrichment factor (EF) values were outstandingly high, >1.5 with values which were often ≥100. The geoaccumulation index, Igeo, was very critical for Cr, Cu, Hg and Ni, showing an Igeo in the range of strongly polluted (4<Igeo <5) and very strongly polluted (Igeo>5). The principal component analysis (PCA) and Pearson's correlation matrix (CM), excluded significant contribution from weathering products.
Afficher plus [+] Moins [-]Variations in the concentrations of heavy metals through enforcement of a rest-year system and dredged sediment capping at the Yellow Sea-Byung dumping site, Korea Texte intégral
2017
Chung, Chang-Soo | Song, Ki-Hoon | Choi, Ki-Young | Kim, Young-Il | Kim, Hye-Eun | Jung, Jun-Mo | Kim, Chang-Joon
In 2014, the concentrations of 13 heavy metals in surface sediments from 14 sampling stations were analyzed and compared to samples from previous years to evaluate the remediation effectiveness of the “rest-year” (RY) system and capping with dredged material at the Yellow Sea-Byung dumping site offshore Korea. Since the 2006 introduction of the RY system, annual variations in metal concentrations at stations within the RY zone have gradually decreased over time. Heavy metal concentrations at most stations were lower than sediment quality guidelines, indicating the success of the RY system. Additionally, the effects of capping the contaminated sediment with dredged materials were investigated. The results indicate that dredged materials successfully capped the contaminated sediment within the dredged material dumping area, as the concentrations of Cr and total organic carbon were significantly reduced. We conclude that dredged materials may be used as capping materials for the remediation of contaminated sediments.
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