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Characterization and source identification of trace elements in airborne particulates at urban and suburban atmospheres of Tabriz, Iran Полный текст
2016
Gholampour, Akbar | Nabizadeh, Ramin | Hassanvand, Mohammad Sadegh | Taghipour, Hasan | Rafee, Mohammad | Alizadeh, Zahra | Faridi, Sasan | Mahvi, Amir Hossein
Concentration of particulate matter (PM₁₀ and total suspended particulate (TSP)) and their elemental constituents were measured to identify the major sources of elements in urban and industrial suburban sites in Tabriz, Iran, from September 2012 to June 2013. TSP and PM₁₀ samples were collected using high-volume samplers. Concentrations of 31 elements in aerosols and crustal soil were determined by ICPMS. The most abundant detected metals in the urban sampling sites were Al (217.5–4019.9 ng m⁻³), Fe (272.5–7658.0 ng m⁻³), Pt (4.7–1994.4 ng m⁻³), and P (13.6–2054.8 ng m⁻³(for TSP and Al (217.6–3687.3 ng m⁻³), Fe (197.1–3724.9 ng m⁻³), Pt (65.9–2054.5 ng m⁻³), and P (11.0–756.6 ng m⁻³(for PM₁₀. In the suburban sampling site, the most abundant detected metals were Al (2083.0–9664.0 ng m⁻³), Fe (360.0–7221.5 ng m⁻³), P (229.4–870.5 ng m⁻³), and Ti (137.3–849.7 ng m⁻³) for TSP and Al (218.5–4179.6 ng m⁻³), Fe (106.3–2005.1 ng m⁻³), P (251.9–908.4 ng m⁻³), and Ba (10.6–584.9 ng m⁻³) for PM₁₀. For the crustal soil, the most abundant detected elements included Al (60,088–60,694 ppm), Fe (19,886–20,474 ppm), Ti (894–3481 ppm), and Si (365–4246 ppm). Key emission sources were identified, and the concentrations contributed from individual sources were estimated. Enrichment factor (EF) explaining a preponderance of the variance in the data was applied to the datasets. EF calculations revealed that non-crustal trace elements were more enriched in the urban than suburban sampling sites. Results of the factor analysis on the elements showed that emissions from road traffic (involving oil and fuel combustions by vehicles, platinum group elements from vehicle exhaust, and resuspension of particulate matter from polluted soil) and construction dust from nearby construction sites and electricity generation plant were the major contributors of anthropogenic metals at ambient atmosphere in Tabriz. Results of this study elucidated the need for developing pollution control strategy, especially vehicle exhaust control, and creating green spaces around the city.
Показать больше [+] Меньше [-]Wet deposition of persistent organic pollutants (POPs) in Izmir, Turkey Полный текст
2016
Cetin, Banu | Odabasi, Mustafa | Bayram, Abdurrahman
Concentrations of several polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polycyclic aromatic hydrocarbons (PAHs), and polybrominated diphenyl ethers (PBDEs) were measured in precipitation (n = 33) at a suburban site in Izmir, Turkey. Total (dissolved + particle) volume weighted mean (VWM) concentrations for Σ₁₆PAHs, Σ₁₈PCBs, Σ₁₇OCPs, and Σ₇PBDEs were 785, 19.2, 50.5, and 29.6 ng l⁻¹, respectively. Low molecular weight (LMW) compounds (acenaphthylene, fluorene, phenanthrene) and congeners (PCB-18, 28, and 31) dominated the PAH and PCB concentrations, respectively. For PBDEs, BDE-209, and for OCPs, chlorpyrifos, a currently used pesticide, were the predominant compounds. Annual Σ₇PBDEs flux was 18.74 μg m⁻² year⁻¹. PBDE fluxes were mainly in dissolved phase for all congeners except BDE-209 which had comparable proportions in both phases. Annual flux for Σ₁₆PAHs was 497.4 μg m⁻² year⁻¹; higher molecular weight (MW) PAH fluxes had comparable amounts in both phases while lower MW ones were mostly in dissolved phase. Wet deposition fluxes for Σ₁₈PCBs and Σ₁₇OCPs were 9.40 and 31.94 μg m⁻² year⁻¹, respectively, and they were predominantly in dissolved phase. Wet deposition fluxes were compared to previously measured annual dry deposition fluxes at the study site to determine their relative contributions to annual total (dry particle + wet) deposition. Dry deposition was the major removal mechanism for most of the PAHs and PCBs contributing >80 % to total (wet + dry) deposition. However, both processes were comparable for PBDEs. Wet deposition was the predominant process for some OCPs such as α-chlordane, γ-chlordane, and trans-nonachlor while both processes were comparable for chlorpyrifos and heptachlor epoxide.
Показать больше [+] Меньше [-]Acute toxicity assessment of explosive-contaminated soil extracting solution by luminescent bacteria assays Полный текст
2016
Xu, Wenjie | Jiang, Zhenming | Zhao, Quanlin | Zhang, Zhenzhong | Su, Hongping | Gao, Xuewen | Ye, Zhengfang
Explosive-contaminated soil is harmful to people’s health and the local ecosystem. The acute toxicity of its extracting solution was tested by bacterial luminescence assay using three kinds of luminescent bacteria to characterize the toxicity of the soil. An orthogonal test L ₁₆ (4⁵) was designed to optimize the soil extracting conditions. The optimum extracting conditions were obtained when the ultrasonic extraction time, ultrasonic extraction temperature, and the extraction repeat times were 6 h, 40 °C, and three, respectively. Fourier transform infrared spectroscopy (FTIR) results showed that the main components of the contaminated soil’s extracting solution were 2,4-dinitrotoluene-3-sulfonate (2,4-DNT-3-SO₃ ⁻); 2,4-dinitrotoluene-5-sulfonate (2,4-DNT-5-SO₃ ⁻); and 2,6-dinitrotoluene (2,6-DNT). Compared with Photobacterium phosphoreum and Vibrio fischeri, Vibrio qinghaiensis sp. Nov. is more suitable for assessing the soil extracting solution’s acute toxicity. Soil washing can remove most of the contaminants toxic to luminescent bacterium Vibrio qinghaiensis sp. Nov., suggesting that it may be a potential effective remediation method for explosive-contaminated soil.
Показать больше [+] Меньше [-]Comparison of translocation methods to conserve metallophyte communities in the Southeastern D.R. Congo Полный текст
2016
Le Stradic, Soizig | Séleck, Maxime | Lebrun, Julie | Boisson, Sylvain | Handjila, Guylain | Faucon, Michel-Pierre | Enk, Terrence | Mahy, Grégory
In southeastern Democratic Republic of Congo, unique metallophyte communities supporting numerous endemic species occurred on the highly mineralized copper cobalt (Cu–Co) hills throughout the province. These hills are economically valuable mineral reserves; mining activities represent therefore a threat to the long-term persistence of these communities. Ex situ conservation program was set up by a mining company to rescue and conserve the diversity of Cu–Co communities until restoration activities are initiated. Two kinds of Cu–Co communities: the steppe and the steppic savanna, were translocated using topsoil spreading and whole-turf translocation. In this study, we assessed the effectiveness of these two techniques in conserving Cu–Co communities and their potential use in future restoration programs. More than 2 years after the translocation, whole-turf translocation appeared to be the better technique for ex situ conservation of endemic Cu–Co species. Not only did whole-turf successfully translocate numerous target species that were not present in the topsoil areas, but it also resulted in fewer ruderal and non-target species compared to topsoil spreading. Topsoil spreading recorded low seedling emergence from seed bank due to large proportions of dormant seeds or the absence of a seed bank, especially for the steppic savanna. Restoration of the steppe is currently more successful than for steppic savanna where the lack of dominant and structuring species likely contributed to divergence in species composition compared to reference ecosystem. Our study stresses the fact that tropical old-growth grasslands, which require probably several centuries to assemble, are difficult to restore or translocate.
Показать больше [+] Меньше [-]Effects of tubificid bioturbation on pore structures in sediment and the migration of sediment particles Полный текст
2016
Li, Yaorui | Hua, Xiuyi | Zheng, Fang | Dong, Deming | Liang, Dapeng | Guo, Zhiyong
In this study, the effects of tubificid bioturbation near the water-sediment interface on pore structures and the migration of sediment particles were evaluated using a series of simulations. In these experiments, the distribution and variation of the tubificid burrows and the macropores in the sediment were investigated by X-ray computed tomography (CT) and digital image collecting, without sampling or disturbing the sediment. The migration of the sediment particles was also determined using CT by adding BaSO₄ microspheres to the sediment as a tracer. The effects of tubificid bioturbation on the distribution and migration of contaminants in the sediment were verified by adding Pb-containing sediment layers to the sediment. The results indicate that after the addition of the tubificids, both the burrows and the macropores in the sediments increased with time, and the rate of increase slowed gradually. With the increased worm density, the burrows and the pore structures also increased. The in-depth distribution of the burrows and macropores was determined by the settlement time of the worms: with the settlement time increasing from 3 to 19 days, the depth of the zone with the highest density of burrows and macropores increased from 0–30 to 30–50 mm and from 0–10 to 30–60 mm, respectively. The distribution of the burrows and macropores was closely related to the distribution of the tubificids. Thickening of the oxidized zones in the superficial sediments in the presence of tubificid bioturbation was also observed. The main action of tubificids on the sediment particles was the transport of particles from the inner sediment (especially in the range of 30–50 mm in depth) to the water-sediment interface. The migration of Pb in the contaminated sediment with tubificid bioturbation could be interpreted by the variation in the burrows and macropores and the migration of sediment particles. Both the formation and the variation in the burrows and macropores, as well as the transport of particles from the inner sediment to the interface, would affect the behaviors of contaminants in the sediment and overlaying water near the water-sediment interface.
Показать больше [+] Меньше [-]Prevalence and antimicrobial susceptibility of Vibrio parahaemolyticus isolated from oysters in Korea Полный текст
2016
Kang, Chang-Ho | Shin, Yujin | Kim, WooRi | Kim, YongGyeong | Song, KiCheol | Oh, Eun-Gyoung | Kim, SuKyung | Yu, HongSik | So, Jae-Seong
Vibrio parahaemolyticus is the most prevalent gastroenteritis-causing pathogen in Korea and in some other Asian countries. It is frequently found in oysters and other seafood. This study monitored changes in the prevalence of V. parahaemolyticus and environmental parameters in oyster aquaculture environments in Korea. From June to October 2014, we tested oysters (Crassostrea gigas) from shellfish-harvesting areas off the west coast of Korea. These 71 isolates were the sum of 16 (22.5 %), 19 (26.8 %), 23 (32.4 %), and 13 (18.3 %) isolates collected in July, August, September, and October, respectively. These 71 isolates had the following profiles of resistance against 16 antibiotics: all isolates were resistant to ampicillin and vancomycin, and 52.2, 50.7, and 50.7 % of isolates exhibited resistance to cephalothin, rifampin, and streptomycin, respectively. PCR analysis for the presence of the species-specific toxR gene confirmed that 38 (53.5 %) of the total 71 isolated strains were positive for V. parahaemolyticus. In PCR analysis for virulence of V. parahaemolyticus, of the 71 isolates tested in the present study, only 38 (53.5 %) were positive for the trh virulence gene and 71 (100 %) was negative for the tdh virulence gene.
Показать больше [+] Меньше [-]Use of multivariate dispersion to assess water quality based on species composition data Полный текст
2016
Jiang, Yong | Xu, Guangjian | Xu, Henglong
Multivariate dispersion is a powerful approach to determine the variability in species composition of a fauna or a flora and has been considered as a broad β-diversity in global ecological research. To explore the availability of the dispersions based on species composition data for assessing water quality, a dataset of ciliated protozoa in a basin ecosystem, northern China, was studied. Samples were collected from five sampling stations, within a significant heterogeneity of environmental stress. The homogeneity of multivariate dispersions in species composition of the ciliate assemblages represented a clear spatial pattern in response to the environmental stress. Multivariate analysis demonstrated that the spatial variation in species composition of the ciliate was significantly correlated with the changes of environmental variables, especially the nutrients, in combination with the salinity and pH, or alone. Furthermore, the dispersion measure was found to be significantly related to the nutrient. Based on our data, we suggest that multivariate dispersion measures based on species presence/absence data might be used as a potential bioindicator of water quality in marine ecosystems.
Показать больше [+] Меньше [-]Changing roles of ammonia-oxidizing bacteria and archaea in a continuously acidifying soil caused by over-fertilization with nitrogen Полный текст
2016
Song, He | Che, Zhao | Cao, Wenchao | Huang, Ting | Wang, Jingguo | Dong, Zhaorong
Nitrification coupled with nitrate leaching contributes to soil acidification. However, little is known about the effect of soil acidification on nitrification, especially on ammonia oxidation that is the rate-limiting step of nitrification and performed by ammonia-oxidizing bacteria (AOB) and archaea (AOA). Serious soil acidification occurs in Chinese greenhouses due to the overuse of N-fertilizer. In the present study, greenhouse soils with 1, 3, 5, 7, and 9 years of vegetable cultivation showed a consistent pH decline (i.e., 7.0, 6.3, 5.6, 4.9, and 4.3). Across the pH gradient, we analyzed the community structure and abundance of AOB and AOA by pyrosequencing and real-time PCR techniques, respectively. The recovered nitrification potential (RNP) method was used to determine relative contributions of AOA and AOB to nitrification potential. The results revealed that soil acidification shaped the community structures of AOA and AOB. In acidifying soil, soil pH, NH₃ concentration, and DOC content were critical factors shaping ammonia oxidizer community structure. AOB abundance, but not AOA, was strongly influenced by soil acidification. When soil pH was below 5.0, AOA rather than AOB were responsible for almost all of the RNP. However, when soil pH ranged from 5.6 to 7.0, AOB were the major contributors to RNP. The group I.1a-associatied AOA had more relative abundance in low pH (pH<6.3), whereas group I.1b tended to prefer neutral pH. Clusters 2, 10, and 12 in AOB were more abundant in acidic soil (pH <5.6), while Nitrosomonas-like lineage and unclassified lineage 3 were prevailing in neutral soil and slightly acidic soil (pH, 6.0–6.5), respectively. These results suggested that soil acidification had a profound impact on ammonia oxidation and more specific lineages in AOB occupying different pH-associated niches required further investigation.
Показать больше [+] Меньше [-]Atmospheric deposition of rare earth elements in Albania studied by the moss biomonitoring technique, neutron activation analysis and GIS technology Полный текст
2016
Allajbeu, Sh | Yushin, N. S. | Qarri, F. | Duliu, O. G. | Lazo, P. | Frontasyeva, M. V.
Rare earth elements (REEs) are typically conservative elements that are scarcely derived from anthropogenic sources. The mobilization of REEs in the environment requires the monitoring of these elements in environmental matrices, in which they are present at trace level. The determination of 11 REEs in carpet-forming moss species (Hypnum cupressiforme) collected from 44 sampling sites over the whole territory of the country were done by using epithermal neutron activation analysis (ENAA) at IBR-2 fast pulsed reactor in Dubna. This paper is focused on REEs (lanthanides) and Sc. Fe as typical consistent element and Th that appeared good correlations between the elements of lanthanides are included in this paper. Th, Sc, and REEs were never previously determined in the air deposition of Albania. Descriptive statistics were used for data treatment using MINITAB 17 software package. The median values of the elements under investigation were compared with those of the neighboring countries such as Bulgaria, Macedonia, Romania, and Serbia, as well as Norway which is selected as a clean area. Geographical distribution maps of the elements over the sampled territory were constructed using geographic information system (GIS) technology. Geochemical behavior of REEs in moss samples has been studied by using the ternary diagram of Sc–La–Th, Spider diagrams and multivariate analysis. It was revealed that the accumulation of REEs in current mosses is associated with the wind-blowing metal-enriched soils that is pointed out as the main emitting factor of the elements under investigation.
Показать больше [+] Меньше [-]Identification of a novel hydroxylated metabolite of 2,2′,3,5′,6-pentachlorobiphenyl formed in whole poplar plants Полный текст
2016
Ma, Cunxian | Zhai, Guangshu | Wu, Huimin | Kania-Korwel, Izabela | Lehmler, Hans-Joachim | Schnoor, Jerald L.
Polychlorinated biphenyls (PCBs) are a group of persistent organic pollutants consisting of 209 congeners. Oxidation of several PCB congeners to hydroxylated PCBs (OH-PCBs) in whole poplar plants has been reported before. Moreover, 2,2′,3,5′,6-pentachlorobiphenyl (PCB95), as a chiral congener, has been previously shown to be atropselectively taken up and transformed in whole poplar plants. The objective of this study was to determine if PCB95 is atropselectively metabolized to OH-PCBs in whole poplar plants. Two hydroxylated PCB95s were detected by high-performance liquid chromatography-mass spectrometry in the roots of whole poplar plants exposed to racemic PCB95 for 30 days. The major metabolite was confirmed to be 4′-hydroxy-2,2′,3,5′,6-pentachlorobiphenyl (4′-OH-PCB95) by gas chromatography-mass spectrometry (GC-MS) using an authentic reference standard. Enantioselective analysis showed that 4′-OH-PCB95 was formed atropselectively, with the atropisomer eluting second on the Nucleodex β-PM column (E2-4′-OH-PCB95) being slightly more abundant in the roots of whole poplar plants. Therefore, PCB95 can at least be metabolized into 4′-OH-PCB95 and another unknown hydroxylated PCB95 (as a minor metabolite) in whole poplar plants. Both atropisomers of 4′-OH-PCB95 are formed, but E2-4′-OH-PCB95 has greater atropisomeric enrichment in the roots of whole poplar plants. A comparison with mammalian biotransformation studies indicates a distinctively different metabolite profile of OH-PCB95 metabolites in whole poplar plants. Our observations suggest that biotransformation of chiral PCBs to OH-PCBs by plants may represent an important source of enantiomerically enriched OH-PCBs in the environment.
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