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1.
渤海中部沉积物铅来源的同位素示踪   总被引:1,自引:1,他引:0  
本研究对渤海中部表层和柱状沉积物中Pb的含量和同位素进行了分析,研究了其时空分布规律,并探讨了其物质来源。结果表明,表层沉积物中Pb的含量为14.54×10-6~59.42×10-6,其含量在渤海湾近岸、黄河口附近、研究区的东北部较高,而在研究区的中部和渤海湾北部含量较低;Pb同位素207Pb/206Pb的值为0.8341~0.8489,208Pb/206Pb的值为2.0828~2.0980。岩心沉积物中Pb含量、同位素组成与表层沉积物相似,整体上较为稳定,但在1990s以来呈现增大的趋势。渤海中部沉积物中Pb以自然来源为主,黄河沉积物是其主要物质来源,但渤海湾北端则与滦河源物质或沿岸侵蚀相关;人类活动影响主要出现在1990s以后,与中国含Pb矿石的燃烧等工业活动相关,但影响微弱,仅在黄河口西北近岸海域、渤海湾等个别站位得到体现。  相似文献   

2.
依据黄河三角洲王子岛海滩潮间带活贝壳和黄河三角洲贝壳堤中贝壳样品的铅同位素记录,初步探讨渤海湾南部最近6000多年来海水铅同位素变化特征及其环境意义,发现:①黄河三角洲贝壳堤中贝壳的铅同位素变化较大,^206Pb/^204Pb范围在18.207~18.648之间,平均值18.470;^207Pb/^204Pb在15.36~15.757之间,平均值15.619;^208Pb/^204Pb在37.947~38.945之间,平均值38.599。②渤海湾南部1.5~2.0kaBP海水放射性成因稳定铅同位素^206Pb、^207Pb、^208Pb相对于现在王子岛海滩潮间带海水亏损。③总体上讲,渤海湾南部4.5~6.0kaBP海水放射性成因稳定铅同位素相对于1.5~2.0kaBP的富集。④黄河三角洲贝壳堤中多数贝壳样品的铅同位素分布在海洋沉积物的范围内,但少数样品分布异常,其^206Ph/^204Pb、^207Pb/^204Pb,^208Pb/^204Pb偏低,可能是受陆地或相邻海区的玄武质中铅的输入的影响。  相似文献   

3.
为了解黄河尾闾及近岸沉积物中重金属的污染特征,采用电感耦合等离子体质谱仪(ICP-MS)测定了黄河河道和河口48个样品中Cr、Cu、Zn、Cd、Pb和As等6种重金属的含量,并对其分布和生态风险进行了评价。结果表明,黄河尾闾及近岸重金属的总含量沿河道至河口方向呈现先增加后降低再增加的趋势,至近岸B断面,As、Pb、Cd和Zn含量呈明显增加趋势,Cu和Cr含量增加幅度较小;黄河河口沉积物中重金属浓度明显高于河道沉积物中重金属的浓度。与我国其他流域相比,研究区域重金属含量处于较低水平。潜在生态风险评价结果表明,黄河尾闾及近岸沉积物6种重金属潜在生态风险系数从高到低依次为:CdAsPbZnCuCr,黄河尾闾及近岸沉积物的潜在生态风险主要由Cd和As引起,两者的贡献率分别为55.90%和29.54%,研究区域生态风险低,污染轻。研究结果将为黄河尾闾及近岸生态保护、环境管理和污染治理提供一定基础数据。  相似文献   

4.
主要针对黄河三角洲表层土壤及沉积物的重金属分布调查,2006—2008年间采集表层土壤样品219个(其中浅海湿地25个),运用先进的现代分析测试手段进行测试,得到黄河三角洲表层土壤中重金属元素的富集程度为:CrPbZnAsCuCdHg,浅海湿地中近海表层沉积物中重金属元素的富集程度较低,并根据研究区重金属的分布,将三角洲划为三个区域,北部油气开采影响区,中部黄河河流影响区,南部农业活动和生活污水排放联合影响区,黄河三角洲表层土壤中虽然具有较高的有机质,但是其对上三角洲平原表层土壤中重金属元素仅具有中等以下的富集作用,而对浅海湿地近海沉积物中的重金属具有中等以上的富集作用。  相似文献   

5.
为了解昌黎黄金海岸保护区表层海域沉积物中重金属的污染状况,采用欧共体标准物质局(Community Bureau of Reference,简称BCR)提出的三级4步提取法分析了沉积物中Cr、Pb、Cu、Zn、Ni的形态特征,并利用次生相原生相分布比值法(Ratio of secondary phrase and primary phrase)和潜在生态风险指数法(Potential ecological hazard index method)对沉积物重金属进行生态风险评价。结果表明,研究区5种重金属含量超过中国浅海沉积物环境背景值;5种金属均以残渣态为主,次生相中,Cu和Ni以可氧化态为主,Cr、Pb、Zn以可还原态为主。次生相原生相分布比值法表明:元素Pb和Ni为保护区表层沉积物中主要的污染元素,Cu、Cr和Zn则较为轻微。潜在生态风险指数法表明:5种金属元素潜在风险指数按顺序依次为Ni>Pb>Cu>Cr>Zn,在各点位均属于低风险级,环境危害较小。  相似文献   

6.
基于莱州湾32个典型站位的表层沉积物样品,系统分析了稀土元素(REE)组成和分布特征以及重金属污染程度和污染来源;探讨了影响重金属和稀土元素分布的环境因素,并从重金属潜在源区、化学蚀变指数(CIA)和REE特征3个角度分析了莱州湾表层沉积物来源。研究表明,稀土元素总量自莱州湾东南部向北部递增,部分稀土元素(Eu、Gd和Tb)含量主要与细粒级的黏土矿物和有机碳含量相关,受化学风化的影响很小。研究区部分站位受到了Cd和Hg的污染,且主要是人类活动富集的;Cu、Pb、Zn可能源于地壳自然风化产物,其中Cu和Zn还与人类活动密切相关;Cr则受自然风化和人类活动的双重影响而富集;大部分重金属含量的累积还受湾内水动力的影响。沉积物源的判别结果显示,研究区CIA平均值为50.83,接近黄河沉积物的CIA值(50.9~59.7),低于中国黄土;研究区稀土元素配分模式和特征参数也与黄河十分接近,表明黄河是莱州湾表层沉积物的重要来源;广利河与潍河-弥河三角洲仅对南部和西南部海域沉积物有贡献,而黄土和山东省土壤对莱州湾沉积物的贡献量相对更少。  相似文献   

7.
渤海中部表层沉积物中重金属赋存相态及来源   总被引:1,自引:1,他引:0  
近年来由于环渤海经济圈的快速发展,渤海接受了来自周边河流、沿岸排污及海上油气开采所产生的大量的重金属等污染物质,使得渤海的生态环境系统面临前所未有的压力。本文采用电感耦合等离子质谱仪(ICP-MS)对采自渤海中部的25个表层沉积物样品中的Cu、Co、Ni、Zn、Pb、Cr、Cd等重金属元素的含量和赋存相态进行了分析,探讨了重金属分布规律、污染状况及来源。研究结果表明,Cu、Co、Ni、Zn、Cr在渤海湾的近岸区域和渤海中部泥质区有较高的含量,而Pb和Cd则在整个研究区的含量都较高;表层沉积物中Cu、Co、Ni、Zn、Cr主要以残渣态形式存在,而Pb和Cd则具有较高的非残渣态含量;生态风险评价结果表明该区表层沉积物未受到Co、Ni、Cr的污染,Cu、Zn、Pb和Cd则为未污染-中等程度污染。重金属元素Co、Ni、Cr以自然来源为主,在沉积物中的分布主要受沉积物物质组成的影响,而Cu、Zn、Pb,尤其是Cd,则受到了人类活动的显著影响。黄河沉积物是研究区表层沉积物中重金属的主要来源,影响范围涵盖了本区大部分区域,但在研究区的北端受到滦河来源物质的影响,渤海湾和研究区中部则受到海河物质和大气沉降来源重金属的一定影响。  相似文献   

8.
于2015年9月,在渤海中部和黄海北部海域调查并采集表层沉积物样品,对样品的粒度、重金属(Cu、Pb、Zn、Cd、Cr)含量及有机碳含量进行了测定,探讨表层沉积物重金属含量、生态风险及其空间分布特征,分析影响生态风险空间分布的因素。结果表明:受河流输入及海洋沉积环境的影响,沉积物重金属含量较高的区域为河口区、渤海湾口以及北黄海中西部,调查区表层沉积物重金属Cu、Pb、Zn和Cr单因子潜在生态风险程度为低污染水平,Cd达到中等污染水平;表层沉积物重金属综合潜在生态风险均为中等水平。  相似文献   

9.
分析了东寨港海水、表层沉积物和生物体中重金属Cu、Zn、Pb、Cd、Hg、类金属As的含量及分布特征,并运用单因子指数法、地积累指数法评价了该调查区重金属污染程度。结果表明:东寨港海水中除Pb的含量符合二类海水标准外,其余含量均符合一类海水标准,且远低于渔业水质标准限值;表层沉积物中典型重金属元素含量都符合海洋沉积物质量一类标准,基本属于无污染区;本区湿地沉积物中的重金属含量比岛内及周边区典型红树林湿地略偏高;红树林及暗滩沉积物中重金属比东寨港水底沉积物重金属含量高,表明河口湾潮滩上的红树林区可能是重金属元素的富集区,东寨港目前可能受到了陆源污染的影响;生物体中重金属含量均符合一类标准,符合无公害水产品的要求。  相似文献   

10.
海南东寨港重金属在多种环境介质中污染状况及评价   总被引:1,自引:0,他引:1  
分析了东寨港海水、表层沉积物和生物体中重金属Cu、Zn、Pb、Cd、Hg、类金属As的含量及分布特征,并运用单 因子指数法、地积累指数法评价了该调查区重金属污染程度。结果表明:东寨港海水中除Pb 的含量符合二类海水标准外, 其余含量均符合一类海水标准,且远低于渔业水质标准限值;表层沉积物中典型重金属元素含量都符合海洋沉积物质量一类 标准,基本属于无污染区;本区湿地沉积物中的重金属含量比岛内及周边区典型红树林湿地略偏高;红树林及暗滩沉积物中 重金属比东寨港水底沉积物重金属含量高,表明河口湾潮滩上的红树林区可能是重金属元素的富集区,东寨港目前可能受到 了陆源污染的影响;生物体中重金属含量均符合一类标准,符合无公害水产品的要求。  相似文献   

11.
本文基于南大洋环流研究最新资料,从资料来源、动力模式以及有待解决的问题几个方面较详细地阐述南大洋环流动力学研究动态。  相似文献   

12.
选取长江口外赤潮多发区沉积物柱状样,在高分辨率测年基础上,通过有机碳、有机碳同位素(δ13C)、生物硅、绿素等多项指标的分析获得了调查海区古生产力的变化信息。并结合近几十年来营养盐浓度及组成结构的变化探讨了海洋浮游藻类组成结构的变化在海洋古环境中的记录。柱状样年代可追溯到20世纪40年代初。δ13C值在柱中的分布为-26.15×10-3~-19.5×10-3,表明有机碳为陆源与海生的混合。生物标志物在柱状样中的分布可大致分为三个阶段,50年代以前含量均较低;50年代至80年代含量均增加,表明海洋浮游藻类活动强烈且以硅藻为主,与此阶段长江口营养盐浓度迅速增加相对应;80年代以后,生物硅的含量下降至整个柱中最低水平,绿素有所降低,但高于50年代前的水平,而有机碳含量增加,表明在该时段硅藻生物量降低,其他藻类生物量有所增加,这与长江口营养盐氮盐持续增加而硅酸盐逐年降低、氮与磷的含量比值、磷与硅的含量比值迅速增大有关。沉积记录还表明此阶段陆源有机碳的贡献增强。  相似文献   

13.
A numerical experiment on the reproduction of the variability in the state of North Atlantic water in 1948–2007 with a spatial resolution of 0.25° has been performed using the global ocean model developed at Institute of Numerical Mathematics, Russian Academy of Sciences (INM RAS), and the Shirshov Institute of Oceanology (IO RAS) (the INM–IO model). The data on the state of the atmosphere, radiation fluxes, and bulk formulas of the CORE-II protocol are used as boundary conditions. Five successive 60-year calculation cycles have been performed in order to obtain the quasi-equilibrium state of a model ocean. For the last 20 years, the main elements of large-scale ocean circulation have been analyzed and compared with the WOA09 atlas data and the results of other models.  相似文献   

14.
This paper analyses the global tendency of the sea level rise (SLR) and its long term influence on the sea level upstream drainage cascade based on the example of the level’s variation in the Vistula Lagoon of the Baltic Sea compared to the other lagoons and coastal regions of the southeastern part of the Baltic Sea. A steady positive trend in the water level variations was revealed; its magnitude varies significantly depending on the time period. In general, during the 100–150 year period, the rate of the SLR in the lagoons and coastal areas of the Baltic Sea (1.7–1.8 mm per year) is close to the SLR rate in the World Ocean. In the second half of the 20th century, the increased rate of the SLR in the lagoons and marine areas became stronger (up to 3.6 mm per year in the Vistula Lagoon and in 1959–2006 in the sea and exceeded the rate of global ocean SLR). It dramatically increased at the end of the last century both in the lagoons and in the sea (up to 10.0–15.0 mm per year). This is the response not only to the global climate warming but it is likely that it is also a response to the changes of the climate driving forces that influence the regimes of the local wind and precipitation in the catchment.  相似文献   

15.
近30年来莱州湾滨海湿地景观格局变化特征研究   总被引:1,自引:0,他引:1       下载免费PDF全文
基于莱州湾滨海湿地特征以及野外实地观测数据,利用landsat遥感影像手段,揭示1990-2018年莱州湾滨海湿地景观格局变化特征,并结合景观指数分析莱州湾滨海湿地异质性。结果表明,1990-2018年间,莱州湾滨海湿地呈现人工滨海湿地面积增加而天然滨海湿地面积减少的趋势。截至2018年莱州湾滨海湿地面积总计1954 km2,其中天然滨海湿地面积约811 km2,人工滨海湿地面积约1143 km2,分别占42%和58%,滨海湿地向建设用地转化的趋势明显。斑块数量(NP)、景观形状指数(LSI)等景观指数值逐年增加,表明莱州湾景观格局变化明显且破碎化程度加重。莱州湾滨海湿地不同岸段之间景观格局变化的驱动机制不完全一样,造成其破碎化程度加重的自然驱动力有河口冲淤、降水量变化等;人工驱动力主要为城市建设、港口码头、集约用海区建设、养殖业和制盐业的开发利用等。以期对莱州湾滨海湿地生态系统退化原因、合理利用和优化土地空间布局、采取有效措施保护及恢复滨海湿地提供一定的技术支持。  相似文献   

16.
Field data in the Oman ophiolite show that the Moho transition zone (MTZ), which is on average 300 m thick above mantle diapirs, reduces to 50 m away from diapirs, with a sharp transition at the outskirts of the diapirs. We show here that this reduction is dominantly due to compaction of a dunitic mush present above diapirs in the MTZ, with upward injection of a wehrlitic magma in the crust, and, to a lesser extent, due to tectonic stretching. In order to explain the fraction of wehrlites injected into the crust, which is in the range of 25%, it is necessary that mantle upwelling is active, with a mantle flow velocity away from diapirs several times faster than the spreading velocity. If this velocity exceeds 5 times the ridge spreading-rate, a significant part of the MTZ may be entrained down into the mantle, flowing away from the diapir as tabular dunites.  相似文献   

17.
1Introduction Besidestheprecipitationandriverdischarges,the watersinthePacificOceanandtheAtlanticOceanare thesourcesoftheArcticOceanwater.TheAtlantic waterenterstheArcticOceanviatheFramStraitand theBarentsSea.Foritsdenserfeatureduetohigh salinity,mostofitsinkstothenorthofSvaldbardand circulatesinallthedeepbasinsintheArcticOcean, formingthedeepandbottomwatersoftheArcticO- cean(Aagaardetal.,1985;Rudelsetal.,1999).The BeringStraitistheonlychannelforthePacificwater toflowintotheArcticOce…  相似文献   

18.
19.
Variations in the speciation of iron in the northern North Sea were investigated in an area covering at least two different water masses and an algal bloom, using a combination of techniques. Catalytic cathodic stripping voltammetry was used to measure the concentrations of reactive iron (FeR) and total iron (FeT) in unfiltered samples, while dissolved iron (FeD) was measured by GFAAS after extraction of filtered sea water. FeR was defined by the amount of iron that complexed with 20 μM 1-nitroso-2-napthol (NN) at pH 6.9. FeT was determined after UV-digestion at pH 2.4. Concentrations of natural organic iron complexing ligands and values for conditional stability constants, were determined in unfiltered samples by titration. Mean concentrations of 1.3 nM for FeR, 10.0 nM for FeT and 1.7 nM for FeD were obtained for the area sampled. FeR concentrations increased towards the south of the area investigated, as a result of the increased influence of continental run off. FeR concentrations were found to be enhanced below the nutricline (below 40 m) as a result of the remineralisation of organic material. Enhanced levels of FeT were observed in some surface samples and in samples collected below 30 m at stations in the south of the area studied, thought to be a result of high concentrations of biogenic particulate material and the resuspended sediments respectively. FeD concentrations varied between values similar to those of FeT in samples from the north of the area to values similar to those of FeR in the south. The bloom was thought to have influenced the distribution of both FeR and FeT, but less evidence was observed for any influence on FeR and FeD. The concentration of organic complexing ligands, which could possibly include a contribution from adsorption sites on particulate material, increased slightly in the bloom area and in North Sea waters. Iron was found to be fully (99.9%) complexed by the organic complexing ligands at a pH of 6.9 and largely complexed (82–96%) at pH 8. The ligands were almost saturated with iron suggesting that the ligand concentration could limit the concentration of iron occurring as dissolved species.  相似文献   

20.
Variability of the Kuroshio in the East China Sea in 1995   总被引:4,自引:0,他引:4  
INTRODUCTIONTherearemanyresearchworksabbottheKUrOShioVTanditSSeaSOnalvacationintheEastChinaho(GUan,1988;Nishizawaetal.,1982;TangandTaShiro,1993;SunandKaneko,1993;Yuanetal.,1990;Yuanetal.,1993;Yuanetal.,1994;Yuanetal.,1995;LiuandYuan,1997a,b).~previou...  相似文献   

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