共查询到20条相似文献，搜索用时 46 毫秒
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研究了总氮NT、总磷Pt、重金属Cu，Zn，Pb和Cd在崇明东滩湿地沉积物中的分布与累积特征。结果表明，NT和重金属表现为：芦苇带〉互花米草带〉海三棱镳草带〉光滩，即从光滩至芦苇带，从南部至北部，NT和重金属的质量分数呈现逐步增加的趋势。由于高潮带以细颗粒为主，有机质含量较高，因此NT和重金属表现出相应的富集；而沉积物PT在各个湖带呈均匀分布，这主要与沉积物中磷的化学形态组成有关。与上海南岸潮滩湿地和世界其他河口湿地相比，东滩湿地沉积物中重金属的质量分数相对较低，表明它是一块保存较为完好未受到污染的天然湿地，这主要与长江径流对污染物的稀释作用有关。 相似文献
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陆架区沉积物中重金属研究的基本方法及其应用 总被引：24，自引：0，他引：24
陆架区沉积物接纳了来自河流、大气、生物、火山等各种途径的颗粒物，是重金属汇集的场所，反映了一定时间内的环境变化特征。本文分析了沉积物中重金属的来源，探讨了沉积物中重金属研究的基本方法：总量分析方法、元素赋存形态、归一化法及重金属的生物毒性等。并探讨了目前沉积物中重金属研究仍存在的问题。 相似文献
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文章依据2018年8月长岛海域表层海洋沉积物调查数据，分析了表层沉积物主要污染物的时空分布特征及主要来源，通过单因子和潜在生态风险指数法评价了沉积物中各种元素的污染程度和潜在的生态风险。结果显示，长岛表层沉积物各污染物的单因子指数P均值由高到低依次排列为：As、Cr、Cu、Cd、Zn、Pb、有机碳、石油类、硫化物、Hg，重金属指标污染情况较理化指标严重；全部站位综合潜在生态风险指数RI＜105，属低生态风险；Cd对综合潜在生态风险指数的贡献率为47.0%，为主要潜在生态风险因子。长岛海域表层沉积物中重金属污染元素的主要来源包括：①大气沉降、海上交通排污带来的重金属污染；②周边区域的养殖面源、生活污水污染等带来的重金属污染；③煤矿和金矿等矿产资源开发等重金属污染。 相似文献
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深圳湾表层沉积物中重金属的分布 总被引：7，自引：0，他引：7
本文在1986年4月至1989年1月间深圳湾12次环境调查资料的基础上,报道了6个调查站的表层沉积物中6种重金属元素(Cu、Pb、Zn、Cd、Cr、N(?))的含量及其时空分布特征,以及表层沉积物中重金属的含量与环境因子的相关分析结果,并且对该湾表层沉积物中重金属的污染程度作出了评价,为今后深圳湾环境质量综合评价提供了背景资料。 相似文献
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莱州湾滨海湿地沉积物重金属的空间分布 总被引：8，自引：0，他引：8
通过研究莱州湾河口区滨海湿地沉积物重金属Pb,Zn,Cd,Cu的含量变化,分析表层沉积物及柱状沉积物,以期了解莱州湾河口区滨海湿地重金属含量的区域性变化,并从柱状沉积物剖面了解沉积物重金属累积的历史变化。研究结果表明,莱州湾河口区与邻近海域沉积物重金属含量在空间分布上与垂直分布上均呈现一定幅度的变化,且高浓度重金属显示区域内重金属呈现污染状况;在沉积物柱状剖面中,发现重金属含量在上层有大幅度增加之现象。另外,利用围隔式生态实验装置研究了该滨海湿地区域污染沉积物中重金属Pb,Zn,Cd,Cu在海水环境中的行为。结果表明,海水中的还原环境能抑制污染沉积物中重金属的释放,有助于体系中原有的重金属清除出水,而低生产力条件下,Pb,Zn表现出释放行为;高生产力和高悬浮物含量条件下,Pb和Zn表现出先释放后迁移,而Cd和Cu则呈现出相反的现象。 相似文献
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在调查现有沉积物分布和地貌背景下,进一步研究了钦州湾-北海近岸水域表层沉积物重金属与有机质分布特征,进行了含量对比与变化模拟,分析了重金属与有机质的关系。结果表明,研究区重金属平均含量在0.039×10-6～47.1×10-6之间,有机质平均含量0.85%,空间变异性均比较大,犀牛脚至三娘湾近岸、北海港区是多种重金属的聚集之处,空间梯度往往也比较大;不同类型沉积物中,重金属向细颗粒聚集效应明显,含量最大增幅为153%,平均含量在TY沉积物中达到最高,重金属与有机质相关性总体也较好,且Zn、Pb、As、Cu、Cd、Hg含量依次以对数方式递减;重金属含量分布与地貌类型也有一定关系,沉积了较多细颗粒物质的水下斜坡,重金属含量普遍要高;从三项典型的重金属Cu、Pb、Zn垂直分布来看,在1.0m左右开始明显增加,应与气候变化与人类影响有关;进行了沉积物质量评价,得出重金属质量指数在0.02～1.31之间,Cu、Pb、Zn、Cd、Hg和有机质均为一类沉积物,As出现了二类沉积物,与前人评价结果一致。 相似文献
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通过对丁字湾海域126个表层沉积物重金属(Hg、Cu、Pb、Zn、Cd、Cr、As、Ni)含量的测定及分析,采用潜在生态危害指数法、内梅罗指数法、地质累计指数法等多种评价方法,对研究区海域环境进行评价。结果表明,丁字湾海域表层沉积物中重金属含量主要集中在丁字湾湾口周边海域,Hg、Cd、As、Pb、Cu、Cr、Zn平均含量分别为0.02、0.08、8.38、15.31、11.49、60.96、46.42μg/g。利用不同的评价方法,可以看出丁字湾海域表层沉积物重金属元素总体呈未污染—轻微污染的现状,这与区内砂质沉积物广泛分布以及不活跃的人类活动密不可分。 相似文献
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《中国海洋大学学报(自然科学版)》2020,(Z1)
本文通过整编2000—2016年长江流域沉积物重金属研究数据,对7种重金属(铜、汞、铅、锌、镉、铬和砷)的含量、空间分布和赋存形态比例进行分析总结,并对其污染风险进行评价。研究结果发现沉积物中镉(Cd)含量超标最严重;从污染风险看,Cd在沉积物中的累积程度和生态风险要远高于另外6种重金属;从赋存形态看,Cd在沉积物中以酸提取态(B1)为主,生物可利用性要高于另外6种重金属,易在环境中迁移转化。本文结果表明Cd是长江流域沉积物的首要重金属污染元素和优控重金属元素。优先关注并重点防控沉积物Cd污染对控制长江流域重金属污染存在积极作用。 相似文献
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Arne Schnack-Friedrichsen Angela M. Davis Jim D. Bennell Dei G. Huws 《Marine Georesources & Geotechnology》2001,19(4):221-243
The interdependence between the seismo-acoustic properties of a marine sediment and its geotechnical/physical parameters has been known for many years, and it has been postulated that this should allow the extraction of geotechnical information from seismic data. Though in the literature many correlations have been published for the surficial layer, there is a lack of information for greater sediment depths. In this article, a desktop study on a synthetic seafloor model illustrates how the application of published near-surface prediction equations to subsurface sediments (up to several tens of meters burial depth) can lead to spurious predictions. To test this further, acoustic and geotechnical properties were measured on a number of sediment core samples, some of which were subjected to loading in acoustically-equipped consolidation cells (oedometers) to simulate greater burial depth conditions. For low effective pressures (representing small burial depths extending to around 10 meters subsurface), the general applicability of established relationships was confirmed: the prediction of porosity, bulk density, and mean grain size from acoustic velocity and impedance appears generally possible for the investigated sedimentary environments. As effective pressure increases through, the observed relationships deviate more and more from the established ones for the near-surface area. For the samples tested in this study, in some instances increasing pressure even resulted in decreasing velocities. There are several possible explanations for this abnormal behavior, including the presence of gas, overconsolidation, or bimodal grain size distribution. The results indicate that an appropriate depth correction must be introduced into the published prediction equations in order to obtain reliable estimates of physical sediment properties for greater subsurface depths. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2000,23(1):55-61
Specific properties of the interannual sea level variations and annual tides in the Northwestern Pacific were studied. Several tide stations were monitored. The monthly mean sea level for the year of 1995 was analyzed at each tide station. A seismic event in 1995, some tectonic activity around the subject area, and the Kuroshio (the oceanic western boundary current) may possibly contaminate results which would have occurred from the astronomical annual tide alone. 相似文献
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The effect of different fixation and storage protocols on the flow cytometric (FCM) simultaneous analysis of bacterioplankton and phytoplankton in coastal seawater samples (Mediterranean coastal lagoons) was investigated. FCM measurements (cell number, fluorescence and scatter characteristics) were obtained through DAPI staining. Three fixatives [glutaraldehyde (GA), formaldehyde (FA) and paraformaldehyde (PFA)] and two storage (3 months duration) methods (5 °C and −196 °C) were tested. Two dominant populations were detected in studied samples: bacteria and eukaryotic picophytoplankton. Adding fixatives (2% final concentration) appears necessary to obtain FCM exhaustive counts of all the bacteria and phytoplanktonic cells. This was related to the permeation effect of fixatives which allowed a better DAPI staining of the cells. Maximum fluorescence, i.e. optimal staining of the cells was obtained with FA or PFA, and significant lower fluorescences with GA. Fixed samples stored at 5 °C induced rapid cell loss. Only storage in liquid nitrogen of samples fixed with FA or PFA, allows mid-term (≥4 months) preservation of bacteria or picophytoplankton cell numbers, and limited evolution of DAPI-induced fluorescence and scatter characteristics. 相似文献
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《海洋学报(英文版)》2014,(9):F0003-F0003
<正>Acta Oceanologica Sinica(AOS)is a comprehensive academic journal edited by the Editorial Committee of Acta Oceanologica Sinica and is designed to provide a forum for important research papers of the marine scientific community which reflect the information on a worldwide basis.The journal publishes scholarly papers on marine science and technology,including physics,chemistry,biology, 相似文献
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The relationship between the flux of exotic benthic foraminiferal tests (i.e. tests which are supplied from open-sea sources alone) in a tidal inlet and that of bulk sediment was analysed, which can be expressed as two first-order linear equations. According to this relationship, in order to determine net sediment transport directions in the entrance, the test concentration in surficial sediments of the tidal basin can be compared against a ‘ critical level ’. The critical level is determined for the conditions that no net transport of bulk sediment is present within the entrance. If the observed concentration (averaged over the tidal basin) is higher than the simulated critical level, then the net sediment transport is directed to landward. This method is applied to the analysis of net sand transport at Christchurch Harbour, a tidal inlet system located in southern England. In this investigation, concentrations of exotic foraminiferal tests in the surficial sediments of the tidal basin and ebb tidal delta area were obtained from the analysis of sea-bed sediment samples. A series of probable critical levels were calculated based upon the data sets with regard to: (1) sediment discharge from the rivers; (2) magnitude of sediment discharge within the entrance during the ebb; (3) the test concentration outside the harbour; (4) the thickness of the moving layer; and (5) two parameters associated with dispersive processes. The results show that the concentration in the tidal basin sediment is higher than a number of simulated critical concentrations for representative cases. Consequently, the high level of the concentration of exotic benthic foraminiferal tests within the harbour should be explained as a result of landward net transport of sands within the entrance. 相似文献
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Coastal inundation associated with extreme sea levels is the main factor which leads to the loss of life and property whenever a severe tropical cyclonic storm hits the Indian coasts. The Andhra and Orissa coasts are most vulnerable for coastal inundation due to extreme rise in sea levels associated with tropical cyclones. Loss of life may be minimized if extreme sea levels and associated coastal flooding is predicted well in advance. Keeping this in view, location specific coastal inundation models are developed and applied for the Andhra and Orissa coasts of India. Several numerical experiments are carried out using the data of past severe cyclones that struck these regions. The simulated inland inundation distances are found to be in general agreement with the reported flooding. 相似文献
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Hoi-Soo Jung Kap-Sik Jeong Yong-Shik Chu Sung-Hyun Park Ki-Hyune Kim 《Marine Georesources & Geotechnology》2001,19(3):181-195
Grain size and water content in box-core sediments from the Clarion-Clipperton fracture zone (C-C zone) in the northeast equatorial Pacific were analyzed in detail to understand the downcore variations across a hiatus between Quaternary and Tertiary layers. Grain-size distributions in the topmost core sediments show two modes: a coarse mode (peaked at 50 μm) and a fine mode (at 2-25 μm). The coarse mode disappears gradually with depth accompanied by the dissolution of siliceous fossil tests, whereas the fine mode coarsens due to the formation of authigenic minerals. Water content increases abruptly across a color boundary between an upper pale brown layer and a lower dark brown layer that is the hiatus between Quaternary and Tertiary layers. Abundant smectites and microvoid molds, which are created by the prolonged fossil dissolution in the underlying sediment, are attributed for the abrupt downcore variation of water content. Overall variations in grain size and water content in the topmost core sediments in the western C-C zone are possibly constrained by the dissolution of biogenic siliceous fossils. Variations in geotechnical properties related to these changes must be considered in the design of nodule collectors. 相似文献
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Shigehisa Nakamura 《Marine Geodesy》2001,24(1):27-33
This article concerns an interrelation between the sea levels and the western boundary flow near a tectonic boundary in a local zone in the Northwestern Pacific. In this zone, sea level variations at stations located on the coast facing the Pacific are studied to find the interrelation between variations of the Kurosio flow as an index of the distance of the flow axis off a specific coast. The result is discussed after data processing of the monthly means of the sea levels, and a notice is taken of variations caused by active crustal upheavals during a seismic event, a local earthquake. 相似文献