Assessment of tributyltin contamination in a shipyard area using a mussel transplantation approach     

Kim NS  Shim WJ  Yim UH  Ha SY  Park PS 《Marine pollution bulletin》2008,57(6-12):883-888

Mussels (Mytilus galloprovincialis) were transplanted to seven stations around a large shipyard for 126 days to evaluate tributyltin (TBT) contamination. Although the application of TBT-based paints to ships is totally banned in Korea, butyltin compounds were found to accumulate in mussels following transplantation. Concentrations of TBT and total butyltins in transplanted mussels near the shipyard were in the range of 40-350 ng Sn/g and 74-530 ng Sn/g on a dry weight basis, respectively. Obviously, low TBT concentrations (6.0-53 ng Sn/gdw) were determined in mussels at four stations outside the shipyard. A negative gradient of TBT concentrations and TBT portion to total butyltin concentrations were found in both the surface water and transplanted mussels according to distance from the shipyard. In addition, TBT concentrations in surface water and transplanted mussels showed significant correlation (r(2) = 0.71; p < 0.001). These results indicate that the shipyard still releases fresh TBT into surrounding waters even after TBT regulation in Korea, and mussel transplantation is useful in evaluating TBT contamination in shipyard area.  相似文献   

Effects of Wastewater-borne Heavy Metals on Mangrove Plants and Soil Microbial Activities   总被引：11，自引：0，他引：11  

M. W. Yim  N. F. Y. Tam   《Marine pollution bulletin》1999,39(1-12):179-186

Effects of wastewater-borne heavy metals on growth of young plants (9-month-old Bruguiera gymnorrhiza) and soil microbial activities in mangrove microcosms were evaluated. During the 26-week loading period, each mangrove microcosm received 31.2 litres synthetic wastewater of three strengths: normal, medium (5 times of normal strength) and strong (10 times of normal strength). Normal strength wastewater had Cu, Zn, Cd, Cr and Ni concentrations of 3, 5, 0.2, 2 and 3 mg l⁻¹, respectively. Plant growth and total plant biomass in wastewater-treated microcosms were lower than that in the control, and the maximum reduction was found in microcosms receiving strong wastewater. Alkaline phosphatase activity and ATP contents of the mangrove soils receiving wastewater were also reduced. More than 95% reduction in these two parameters was found in soils loaded with strong wastewater. Microtox test demonstrated that soil elutriates obtained from microcosms receiving strong wastewater were of the greatest toxicity (EC₅₀ was 23%). These results show that high concentrations of heavy metals present in strong wastewater were toxic and posed negative effects to both mangrove plants and soil microbial activities. Microbial activities were generally more sensitive to the toxicity of heavy metals than plants.  相似文献   

Revisiting the Climatology of Atmospheric Blocking in the Northern Hemisphere     

Ho Nam CHEUNG  ZHOU Wen  Hing Yim MOK  Man Chi WU  Yaping SHAO 《大气科学进展》2013,30(2):397-410

In addition to the occurrence of atmospheric blocking,the climatology of the characteristics of blocking events,including duration,intensity,and extension,in four seasons over the Northern Hemisphere was analyzed for the period 1950-2009.The seasonality and spatial variations of these characteristics were studied according to their longitudinal distributions.In general,there were sharp discrepancies in the blocking characteristics between winter and summer,and these differences were more prominent over the Atlantic and Pacific Oceans.The blocking not only occurred more frequently but also underwent stronger amplification in winter;likewise,the blocking occurred less frequently and underwent weaker amplification in summer.There are very strong interrelationships among different blocking characteristics,suggesting that they are supported by similar physical factors.In addition,the relationship between blocking over different regions and East Asian circulation was examined.Ural-Siberia is a major blocking formation region in all seasons that may exert a downstream impact on East Asia.The impact is generally weak in summer,which is due to its lower intensity and smaller duration.However,the extratropical circulation over East Asia in summer can be disturbed persistently by the frequent occurrence of blocking over the Asian continent or the Western Pacific.In particular,the blocking frequency over the Western Pacific significantly increased during the study period.This climatological information provides a background for studying the impact of blocking on East Asian circulation under both present and future climate conditions.  相似文献   

Ocean mixed layer processes in the Pacific Decadal Oscillation in coupled general circulation models   总被引：1，自引：1，他引：0  

Bo Young Yim  Yign Noh  Sang-Wook Yeh  Jong-Seong Kug  Hong Sik Min  Bo Qiu 《Climate Dynamics》2013,41(5-6):1407-1417

It is investigated how the Pacific Decadal Oscillation (PDO) is simulated differently among various coupled general circulation models (CGCMs), and how it is related to the heat budget of the simulated ocean mixed layer, which includes the surface heat flux and ocean heat transport. For this purpose the dataset of the climate of the 20th Century experiment (20C3M) from nine CGCMs reported to IPCC’s AR4 are used, while the MRI and MIROC models are examined in detail. Detailed analyses of these two CGCMs reveal that the PDO is mainly affected by ocean heat transport rather than surface heat flux, in particular in the MRI model which has a larger contribution of ocean heat transport to the heat budget. It is found that the ocean heat transport due to Ekman advection versus geostrophic advection contributes differently to the PDO in the western and central North Pacific. Specifically, the strength of PDO tends to be larger for CGCMs with a larger ocean heat transport in the region.  相似文献   

Pacific Decadal Oscillation and its relation to the extratropical atmospheric variation in CMIP5   总被引：1，自引：0，他引：1  

Bo Young Yim  MinHo Kwon  Hong Sik Min  Jong-Seong Kug 《Climate Dynamics》2015,44(5-6):1521-1540

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Correlation between magnetic susceptibility and distribution of heavy metals in contaminated sea-floor sediments of Hong Kong Harbour     

L. S. Chan  C. H. Yeung  W. W.-S. Yim  O. L. Or 《Environmental Geology》1998,36(1-2):77-86

 Magnetic susceptibility measurements were conducted on 24 vibrocores obtained from an area located off the northeastern coast of Lantau Island in Hong Kong. High intensities of magnetic susceptibility were detected in the uppermost sections of the majority of the cores. Several magnetic parameters measured for one of the cores suggest that the variations in the magnetic characteristics over depth are mainly due to varying concentrations of the magnetic minerals. Since a strong correlation has been found between magnetic susceptibility and the heavy metals Pb, Cu, Zn and Cr, an anthropogenic contamination origin is thought to be the cause. The present study shows that magnetic susceptibility is a fast, inexpensive and non-destructive method for the detection and mapping of contaminated sediments. Received: 12 August 1997 · Accepted: 18 November 1997  相似文献   

Prediction of Meiyu rainfall in Taiwan by multi-lead physical–empirical models     

So-Young Yim  Bin Wang  Wen Xing  Mong-Ming Lu 《Climate Dynamics》2015,44(11-12):3033-3042

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Prediction of early summer rainfall over South China by a physical-empirical model   总被引：1，自引：0，他引：1  

So-Young Yim  Bin Wang  Wen Xing 《Climate Dynamics》2014,43(7-8):1883-1891

In early summer (May–June, MJ) the strongest rainfall belt of the northern hemisphere occurs over the East Asian (EA) subtropical front. During this period the South China (SC) rainfall reaches its annual peak and represents the maximum rainfall variability over EA. Hence we establish an SC rainfall index, which is the MJ mean precipitation averaged over 72 stations over SC (south of 28°N and east of 110°E) and represents superbly the leading empirical orthogonal function mode of MJ precipitation variability over EA. In order to predict SC rainfall, we established a physical-empirical model. Analysis of 34-year observations (1979–2012) reveals three physically consequential predictors. A plentiful SC rainfall is preceded in the previous winter by (a) a dipole sea surface temperature (SST) tendency in the Indo-Pacific warm pool, (b) a tripolar SST tendency in North Atlantic Ocean, and (c) a warming tendency in northern Asia. These precursors foreshadow enhanced Philippine Sea subtropical High and Okhotsk High in early summer, which are controlling factors for enhanced subtropical frontal rainfall. The physical empirical model built on these predictors achieves a cross-validated forecast correlation skill of 0.75 for 1979–2012. Surprisingly, this skill is substantially higher than four-dynamical models’ ensemble prediction for 1979–2010 period (0.15). The results here suggest that the low prediction skill of current dynamical models is largely due to models’ deficiency and the dynamical prediction has large room to improve.  相似文献   

Magnetic properties and heavy-metal contents of contaminated seabed sediments of Penny's Bay, Hong Kong   总被引：12，自引：0，他引：12  

Chan LS  Ng SL  Davis AM  Yim WW  Yeung CH 《Marine pollution bulletin》2001,42(7):569-583

Magnetic properties and heavy-metal concentrations of vibrocore samples were found to be potential indicators of shipping contamination in seabed sediments in Hong Kong Harbour. Geochemical results of 74 vibrocores located off Penny's Bay on Lantau Island revealed an enrichment of heavy metals in the upper 1-2 m of the cores within the eastern part of the study site. Whole-core magnetic susceptibility measurements also showed a greater concentration of magnetic particles in the surficial layer of these cores. A significant correlation exists between the magnetic susceptibility and the concentrations of Pb, Zn and Cu, as well as the Tomlinson pollution load index (PLI). The proximity of these cores to a major navigation fairway and an anchorage site suggests probable contamination of the surficial seabed sediments by shipping-related wastes. A study of the magnetic properties of one of the cores, VT60, revealed a difference in the magnetic properties between the contaminated and the uncontaminated sediments. Samples from the contaminated zone exhibited relatively stronger magnetic remanence and susceptibility. The two groups of samples also formed distinct trends on the hysteresis ratios plot. A level of unusually high magnetic susceptibility within the contaminated zone was attributable to the presence of strongly magnetized granules, which were probably refuse from shipping-related activities. Geochemical and magnetic results were also conducted on samples of different size-fractions from this core. The < 63 microns fraction was found to contain a relatively higher magnetic susceptibility and greater heavy-metal content.  相似文献   

沪杭高速公路GPS线路控制网的测设   总被引：3，自引：0，他引：3  

施一民 《测绘工程》1996,5(2):45-48

采用ＧＰＳ定位技术先建立高精度线路控制网，然后再分段加密线路导线，不仅精度高、施测方便，而且充分保证了线路导线点的可靠性，与以往按支导线布设的线路导线相比，具有诸多优点。文中介绍了在沪杭高速公路上应用ＧＰＳ定位技术的经验。  相似文献