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1.
烟台近岸典型生态区沉积物重金属形态分布及其污染状况   总被引:3,自引:0,他引:3  
运用Tessier连续提取法,对烟台海岸带3个典型生态敏感区表层沉积物重金属Cr、Cu、Cd、Pb、Zn、Ni的形态分布和污染状况进行了分析研究。结果表明,研究区域中河口区与排污口区重金属Cr、Cu、Cd、Zn和Ni的含量较高,尤其是Cd污染严重。养殖区基本符合海洋沉积物质量第1类标准;重金属Cr、Cu、Pb、Zn和N...  相似文献   

2.
海洋沉积物中重金属的活性形态对于指示沉积物污染状况具有重要作用;为探寻简洁且能够有效提取重金属活性形态的浸提方法;实验研究了0.1 mol/L和1 mol/L盐酸的单级提取和欧共体标准局(European Community Bureau of Reference)提出的BCR分级提取法对胶州湾表层沉积物中重金属(Cr、Cu、Ni、Pb、Zn)和Al、Fe、Mn的浸取效果。结果显示;3种提取方法提取的金属含量呈显著正相关关系;两种浓度的稀盐酸对BCR方法中的酸可提取态和可还原态金属均具有较好浸提效果;但对可氧化态金属浸提能力相对较弱。不同提取方法的人为信号指数(ASI)计算结果表明;BCR浸取法提取结果的金属ASI值最大;表明其对沉积物中金属活性形态提取效率较高;1 mol/L HCl提取结果的金属ASI值最低;可能是较高浓度强酸使沉积物较大颗粒内层中“惰性”金属被浸取出来;“增加”了金属活性组分的污染讯息信号;对沉积物中Cu、Pb和Zn而言;0.1 mol/L HCl提取结果的ASI值与BCR方法接近。经过Al归一化后;0.1 mol/L HCl浸提的重金属含量的空间分布与胶州湾的实际污染状况相吻合;表明0.1 mol/L的HCl在一定程度上能够代替复杂的BCR浸取法;此方法可简化重金属活性形态的提取步骤;适合大范围沉积物重金属污染评价。  相似文献   

3.
基于Landsat-8 OLI影像的南沙群岛岛礁遥感调查研究   总被引:1,自引:0,他引:1  
海洋沉积物中重金属的活性形态对于指示沉积物污染状况具有重要作用;为探寻简洁且能够有效提取重金属活性形态的浸提方法;实验研究了0.1 mol/L和1 mol/L盐酸的单级提取和欧共体标准局(European Community Bureau of Reference)提出的BCR分级提取法对胶州湾表层沉积物中重金属(Cr、Cu、Ni、Pb、Zn)和Al、Fe、Mn的浸取效果。结果显示;3种提取方法提取的金属含量呈显著正相关关系;两种浓度的稀盐酸对BCR方法中的酸可提取态和可还原态金属均具有较好浸提效果;但对可氧化态金属浸提能力相对较弱。不同提取方法的人为信号指数(ASI)计算结果表明;BCR浸取法提取结果的金属ASI值最大;表明其对沉积物中金属活性形态提取效率较高;1 mol/L HCl提取结果的金属ASI值最低;可能是较高浓度强酸使沉积物较大颗粒内层中“惰性”金属被浸取出来;“增加”了金属活性组分的污染讯息信号;对沉积物中Cu、Pb和Zn而言;0.1 mol/L HCl提取结果的ASI值与BCR方法接近。经过Al归一化后;0.1 mol/L HCl浸提的重金属含量的空间分布与胶州湾的实际污染状况相吻合;表明0.1 mol/L的HCl在一定程度上能够代替复杂的BCR浸取法;此方法可简化重金属活性形态的提取步骤;适合大范围沉积物重金属污染评价。  相似文献   

4.
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   

5.
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   

6.
长江口湿地沉积物中的氮、磷与重金属   总被引:7,自引:0,他引:7       下载免费PDF全文
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   

7.
通过现场调查研究报道了长江口及邻近海域表层沉积物中重金属、有机碳、石油类、硫化物以及氮磷的分布、来源以及沉积物环境质量.结果显示,长江口及邻近海域表层沉积物中重金属、有机碳、石油类、硫化物以及氮磷的分布很不均匀,除硫化物外,重金属、有机碳、石油类以及氮磷基本呈现长江口和杭州湾东北近岸的上海外海出现高值,其他区域浓度较低...  相似文献   

8.
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  
杨美兰  陆超华 《台湾海峡》1992,11(3):192-196
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   

9.
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   

10.
深圳铜鼓航道表层沉积物中重金属含量及潜在生态危害   总被引:1,自引:0,他引:1  
根据2009年9月深圳铜鼓航道表层沉积物中重金属含量的调查资料,采用单因子指数法和Hakanson生态风险指数法对其重金属污染特征及潜在生态风险进行了分析和评价.结果表明:重金属含量较低,属于国家一类海洋沉积物;表层沉积物已受到重金属Pb、Zn、As的污染,所有站住重金属综合污染指数均>5,达到中等污染水平,各重金属污...  相似文献   

11.
In order to assess the impact of deep-sea mining on the in situ benthic life, we measured the microbial standing stock and concentration of organic nutrients in the deep-sea sediments of the Central Indian Ocean Basin in the Indian pioneer area. Sediments were collected using box core and grab samples during September 1996. The total bacterial numbers ranged from 10 10 -10 11 cells per g -1 dry weight sediment. There was a marginal decrease in the number of bacteria from surface to 30 cm depth, though the subsurface section registered a higher number than did the surface. The highest numbers were encountered at depths of 4-8 cm. The retrievable number of bacteria were two orders less in comparison with the direct total counts of bacteria. An almost homogeneous distribution of bacteria, total organic carbon, living biomass, and lipids throughout the depth of cores indicates active microbial and benthic processes in the deep sea sediments. On the other hand, a uniform distribution of total counts of bacteria, carbohydrates, and total organic carbon in all the cores indicates their stable nature and suggests that they can serve as useful parameters for long-term monitoring of the area after the benthic disturbance. Further studies on temporal variability in this region would not only verify the observed norms of distribution of these variables but would also help to understand restabilization processes after the simulated benthic disturbance.  相似文献   

12.
An acoustic inversion method using a wide-band signal and two near field receivers is proposed and applied to multiple layered seabed models including a manganese sediment. The inversion problem can be formulated into a probabilistic model comprised of signals, a forward model, and additive noise. The forward model simulates wide-band signals, such as chirp signals, and is chosen to be the source-waveletconvolution plane wave modeling method. The wavelet matching technique, using weighted least-squares fitting, estimates the sediment sound-speed and thickness on which determination of the possible numerical ranges for a priori uniform distribution is based. The genetic algorithm is applied to a global optimization problem to find a maximum a posteriori solution for determined a priori search space. Here the object function is defined by an L 2 norm of the difference between measured and modeled signals. Not only the marginal pdf but also its statistics are calculated by numerical evaluation of integrals using the samples selected during importance sampling process of the genetic algorithm.  相似文献   

13.
海上大直径钢管桩打桩过程中,桩周土体受到强烈扰动而发生强度弱化,掌握桩周土体强度弱化规律对于准确预测打桩过程、保证工程安全具有重要意义。为研究土体强度弱化规律,开展了环剪试验模拟打桩对桩周土体的扰动,测试土体强度随剪切速率的变化规律,建立了描述土体强度弱化规律的拟合公式,引入到打桩分析软件中。研究结果表明:土体的强度折减程度不仅与土体本身的性质有关还受到土体的埋深和剪切速率的影响,埋深越深土体强度折减程度越低,剪切速率越高土体强度折减越高,在打桩分析中可采用这里推荐的线性折减方法来模拟不同深度处土体强度的折减规律。  相似文献   

14.
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   

15.
Oedometer tests have been carried out on 70 undisturbed surficial clays (at approximately 250 mm below the mudline), mostly collected by free-fall corers from sites widely scattered throughout the deep-sea North Atlantic. Acoustic measurements were also made, initially on contiguous samples and ultimately on the same sample using a geophysically instrumented oedometer which also collected electrical resistivity data. Apart from those quiescent areas below the carbonate compensation depth, such as north of the West Indies where very fine clays exist, most of the samples are silty clays whose geotechnical-geophysical properties are dependent on the type of clay minerals present (and their ability to take in moisture), the sand-size fraction, and the quantity of carbonate present. Thus the pure clays have high compressibilities which decrease on the addition of coarse particles, while the converse is true for the acoustic parameters, these increasing with the sand fraction. Using the notion of the intrinsic compression line for all samples, and comparison to it of the measured compression curves, it is clear that, contrary to some previously held ideas, most deep-sea clays are normally consolidated; the addition of carbonate has the effect of creating an open, stronger sediment skeleton. Interestingly, where information is available, the variation with depth of a sample's acoustic velocity follows the void ratio pressure relationship of the compression curve. This allows the construction of an in-situ sediment compression curve using the in-situ geophysical observations.  相似文献   

16.
17.
Particle fluxes were measured 7 m above the sea bottom during the predisturbance, disturbance, and postdisturbance periods by using time series sediment traps attached to seven deep-sea moorings deployed in the INDEX experiment site in the Central Indian Basin. The predisturbance particle fluxes varied between 22.3 to 55.1 mg m -2 day -1 . Increased and variable particle fluxes were recorded by the sediment traps during the disturbance period. The increase observed was 0.5 to 4 times more than the background predisturbance fluxes. The increases in particle fluxes (~4 times) recorded by the sediment trap located in the southwestern direction (DMS-1) were the greatest, which could be the result of preferential movement of resuspended particles generated during the deep-sea benthic disturbance along the general current direction prevailing in this area during the experimental period. Also, the traps located closer to the disturbance area recorded greater fluxes than did the traps far away, across the Deep Sea Sediment Resuspension System path. This variability in recorded particle fluxes by the traps around the disturbance area clearly indicates that physical characteristics such as grain size and density of the resuspended particles produced during the disturbance had an important effect on particle movement. The postdisturbance measurements during ~5 days showed a reduction in particle fluxes of ~50%, indicating rapid particle settlement.  相似文献   

18.
This article reviews information recently available from existing marine and coastal mining for responses to environmental issues affecting marine mining at different depths. It is particularly but not exclusively concerned with those issues affecting seabed biodiversity impact and recovery. Much information has been gathered in the past 10 years from shallow mining operations for construction aggregate, diamonds, and gold, from coastal mines discharging tailings to shallow and deep water, and from experimental deep mining tests. The responses to issues identified are summarized in a series of eight tables intended to facilitate site-specific consideration. Since impacts can spread widely in the surface mixing layer SML, and can affect the biologically productive euphotic zone, the main issues considered arise from the depth of mining relative to the SML of the sea. Where mining is below the SML, the issue is whether it is environmentally better to bring the extraction products to the surface vessel for processing (and waste discharge), or to process the extraction products as much as possible on the seabed. Responses to the issues need to be sitespecific, and dependent on adequate preoperational environmental impact and recovery prediction. For deep tailings disposal from a surface vessel, there are four important environmental unknowns: (1) the possible growth of "marine snow" (bacterial flocs) utilizing the enormous quantities of fine tailings particles (hundreds or thousands of metric tons per day) as nuclei for growth, (2) the possibility that local keystone plankton and nekton species may migrate diurnally down to and beyond the depth of deep discharge and hence be subjected to tailings impact at depth, (3) the burrow-up capability of deep benthos and their ability to survive high rates of tailings deposition, and (4) the pattern and rate of dispersion of a tailings density current through the deep water column from discharge point to seabed. Actions to obtain relevant information in general and site-specifically are suggested.  相似文献   

19.
《海洋学报(英文版)》2014,(8):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   

20.
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