Major human Hepatitis A virus genotype in Hong Kong marine waters and detection by real-time PCR     

Yang N  Chu DL  Wong MM  Qi H  Wu RS  Kong RY 《Marine pollution bulletin》2011,62(12):2654-2658

Marine waters from seven sites around Hong Kong with varying levels of sewage pollution were analyzed for Hepatitis A virus (HAV) by PCR cloning and DNA sequencing of the highly variable VP1/2A junction of the HAV genome. Phylogenetic analysis of 10 PCR clones from each of the HAV-positive marine sites indicated that human HAV genotype IB is the most widely distributed type in Hong Kong waters. A sensitive and quantitative TaqMan-based PCR method targeting the 5′-noncoding region (5′-NCR) of HAV was used to quantify HAV particles in marine water samples along with the total Escherichiacoli counts being enumerated on TBX medium for comparison. Our results showed that no correlation of any significance between HAV and E. coli counts was observed which underscores the inadequacy in using E. coli as a sanitary standard to predict the levels of HAV in marine waters.  相似文献   

Distribution and source apportionments of polychlorinated biphenyls (PCBs) in mariculture sediments from the Pearl River Delta, South China   总被引：1，自引：0，他引：1  

Wang HS  Du J  Leung HM  Leung AO  Liang P  Giesy JP  Wong CK  Wong MH 《Marine pollution bulletin》2011,63(5-12):516-522

Surface and core sediments collected from six mariculture farms in the Pearl River Delta (PRD) were analyzed to evaluate contamination levels of polychlorinated biphenyls (PCBs). The ∑PCBs (37 congeners) concentrations ranged from 5.10 to 11.0 ng g(-1) (mean 7.96 ng g(-1)) in surface and 3.19 to 22.1 ng g(-1) (mean 7.75 ng g(-1)) in core sediments, respectively. The concentrations were significantly higher than that measured in the sediments of their corresponding reference sites, whereby the average enrichment percentages were 62.0% and 42.7% in surface and core sediments, respectively. Significant correlations (R2=0.77, p<0.05) of PCB homologue group proportions between fish feeds and surface mariculture sediments suggested that fish feed input was probably the main source for the enrichment of PCBs. Due to the fact that PCBs could be transferred along food chains, PCB contamination in fish feeds and mariculture sediments should not be overlooked.  相似文献   

Assessment of risk of PCDD/Fs and dioxin-like PCBs in marine and freshwater fish in Pearl River Delta, China     

Wei X  Leung KS  Wong MH  Giesy J  Cai ZW  Wong CK 《Marine pollution bulletin》2011,63(5-12):166-171

Fish consumption is known to be beneficial to human health. However since the age of industrialization, the released/disposed chemical pollutants into water systems make fish a source of various environmental toxicants to humans. In oceanic cities with heavy industrial activities, fish products contribute the greatest proportion of exposure to pollutants. In this study, risks and potential effects of dioxins to health of coastal populations in the Pearl River Delta were assessed. Concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and dioxin-like polychlorinated biphenyls (PCBs) were measured in common fish species purchased at local markets. Concentrations of total dioxins in fish ranged from 0.481 to 9.05 pg TEQ/g wet weight were similar to the lesser concentrations reported for fish from other countries. The greatest concentrations of dioxins were measured in mandarin fish, a carnivorous freshwater fish. Exposure of murine primary leydig and ovarian cells to 2,3,7,8-tetrachlorinated dibenzo-p-dioxins (2,3,7,8-TCDD) reduced the synthesis of progesterone, testosterone and/or estrogen. The reductions were probably via inhibitory effects on the expression of the steroidogenic enzymes, steroidogenic acute regulatory protein (StAR) and cytochrome P450 side-chain cleavage enzyme (P450scc). Based on these reproductive parameters, the concentrations of dioxins and dioxin-like residues represent a moderate health risk due to consumption of fish.  相似文献   

Formation of iron plaque on mangrove roots receiving wastewater and its role in immobilization of wastewater-borne pollutants   总被引：2，自引：0，他引：2  

Pi N  Tam NF  Wong MH 《Marine pollution bulletin》2011,63(5-12):402-411

Iron (Fe) plaque formed on mangrove root increased with wastewater discharge, but the extent was species-specific. For Bruguiera gymnorrhiza, Fe plaque concentration was 0.80 mg g(-1) root d.wt at Day 0 and increased to 4.59, 6.84 and 7.52 mg g(-1) at Day 75 in the fresh water control (FW), synthetic wastewater with pollutant concentrations five times of municipal sewage (5SW) and double of 5SW (10SW) treatments, respectively; the respective increases in Excoecaria agallocha were from 0.70 to 2.37, 10.73 and 13.21 mg g(-1). For Acanthus ilicifolius, similar increase was found in 5SW, but all of the plants were dead in 10SW at Day 75. The concentrations of heavy metals and phosphorus immobilized were positively correlated with the amounts of Fe plaque formed, but the regression coefficients varied among species. The performance of mangrove plants in wastewater treatments was related to the Fe plaque formed and its immobilized wastewater-borne pollutants.  相似文献   

Laboratory Validation of Ultra-Soft Soil Deformation Model     

Myint Win Bo  Victor Choa  Kai Sin Wong  Arul Arulrajah 《Geotechnical and Geological Engineering》2011,29(1):65-74

Ultra-soft soil with high moisture content will experience large strain deformation under one-dimensional compression with little or no gain in effective stress. Such deformation behaviour does not comply with Terzaghi’s effective stress gain theory. The e-log s_v^￠ \sigma_{v}^{\prime } relationship of ultra-soft soil is non-linear with large compression index in the first order of log cycle. This paper proposes three compression indices (C_c1^* C_{c1}^{*} , C_c2^* C_{c2}^{*} and C_c3^* C_{c3}^{*} ) for stresses covering three log cycles. Good prediction of settlement magnitude is possible with these newly proposed compression parameters for ultra-soft soil. In addition, implicit finite difference model applying the large strain theory is also proposed and validated with results from laboratory measurements. The time factor curves for ultra-soft soil with large strain compression are also proposed and validated.  相似文献   

U–Pb and Hf isotopic study of zircons from migmatised amphibolites in the Cathaysia Block: Implications for the early Paleozoic peak tectonothermal event in Southeastern China     

Long-Ming Li  Min Sun  Yuejun Wang  Guangfu Xing  Guochun Zhao  Shoufa Lin  Xiaoping Xia  Lungsang Chan  Feifei Zhang  Jean Wong 《Gondwana Research》2011,19(1):191-201

Amphibolites occur in a number of localities in the Cathaysia Block, some of them have been migmatised and their protoliths represent basaltic magmas erupted in various tectonic settings. Four migmatised amphibolites were collected from Jiangxi and Fujian Provinces. Cathodo-luminescence images of zircons extracted from the representative amphibolites show unzoned or sector-zoned structure. LA-ICP-MS analysis indicates that most zircons have high Th/U ratios and yield U–Pb zircon ages of 446 ± 5, 435 ± 2, 434 ± 4 and 423 ± 2 Ma, respectively. Lu–Hf isotopic analysis on these zircons gives Hf model ages ranging from 900 to 1200 Ma. Based on lithological observations and previously published geochronological data, we interpret that these U–Pb ages record an important tectonothermal event that led to the migmatization. This early Paleozoic (Caledonian) tectonothermal event in the Southeastern China has a great tectonic implication for the evolutionary history of the Cathaysia Block.  相似文献   

InSAR detection of residual settlement of an ocean reclamation engineering project: a case study of Hong Kong International Airport   总被引：2，自引：1，他引：1  

Qing Zhao  Hui Lin  Wei Gao  Howard A. Zebker  Albert Chen  Kin Yeung 《Journal of Oceanography》2011,67(4):415-426

Man-made land or islands that are reclaimed from the sea are suitable for building airports, harbors, and industry parks for material transportation because of their broad air and land spaces. However, the reclaimed foundation settlement process is of public concern, including the continuous impact of ocean processes on its stability. The majority of the buildings and facilities of Hong Kong International Airport (HKIA) are built on a reclaimed foundation. The reclaimed foundation has been in residual settlement since completion of the filling project in 1994. In this study, we use persistent scatterer interferometry (PSI) and ENVISAT (European Satellite) advanced synthetic aperture radar (ASAR) data to detect the residual settlement rates from 19 April 2006 to 9 January 2008. We use ground truth data to develop empirical correction models for correcting systematic biases in the ASAR PSI-detected settlement rates. The corrected data follow the Lorentz distribution well, implying that the residual settlement process is dominated by two modes or categories of settlement rates. The first category represents a relatively stable state and the second category represents a continuous settlement state. A ground settlement rate map of HKIA shows that an area of the Passenger Terminal Building and an area of the Southern Runway are two relatively stable areas. There are two major continuous settlement areas. One covers the airport Midfield. Another is along the coastline, implying that attention should be paid to impacts of ocean processes on the stability of airport foundations.  相似文献   

Dynamic Study on Fracture Problems in Viscoelastic Sedimentary Rocks Using the Numerical Manifold Method     

Zhijun Wu  Louis Ngai Yuen Wong  Lifeng Fan 《Rock Mechanics and Rock Engineering》2013,46(6):1415-1427

The viscoelastic deformation behavior of a sedimentary rock under different loading rates is numerically modeled and investigated by the numerical manifold method (NMM). By incorporating a modified 3-element viscoelastic constitutive mode in the NMM, crack initiation and propagation criteria, and crack identification and evolution techniques, the effects of the loading rates on the cracking behavior of a sedimentary rock, such as crack open displacement, crack sliding displacement, crack initiation, crack propagation and final failure mode, are successfully modeled. The numerical results reveal that under a high loading rate (>1,000 MPa/s), due to the viscoelastic property of the sedimentary rock, not only the structural behavior deviates from that of elastic model, but also different cracking processes and final failure modes are obtained.  相似文献   

Trace element residues in eggs of Little Egret (Egretta garzetta) and Black-crowned Night Heron (Nycticorax nycticorax) from Hong Kong, China     

Lam JC  Tanabe S  Wong BS  Lam PK 《Marine pollution bulletin》2004,48(3-4):390-396

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Microstructural Inhomogeneity and Mechanical Anisotropy Associated with Bedding in Rothbach Sandstone     

Laurent Louis  Patrick Baud  Teng-fong Wong 《Pure and Applied Geophysics》2009,166(5-7):1063-1087

This study present the result of conventional triaxial tests conducted on samples of Rothbach sandstone cored parallel, oblique (at 45 degrees) and perpendicular to the bedding at effective pressures ranging from 5 to 250 MPa. Mechanical and microstructural data were used to determine the role of the bedding on mechanical strength and failure mode. We find that samples cored at 45 degrees to the bedding yield at intermediate level of differential stress between the ones for parallel and perpendicular samples at all effective pressures. Strain localization at high confining pressure (i.e., in the compactive domain) is observed in samples perpendicular and oblique to the bedding but not in samples cored parallel to the bedding. However, porosity reduction is comparable whether compactive shear bands, compaction bands or homogeneous cataclastic flow develop. Microstructural data suggest that (1) mechanical anisotropy is controlled by a preferred intergranular contact alignment parallel to the bedding and that (2) localization of compaction is controlled by bedding laminations and grain scale heterogeneity, which both prevent the development of well localized compaction features.  相似文献