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湖北省是长江流域重要的湖泊分布区,由于河(江)湖关系自然演变和人类活动的双重影响,湖泊数量和湖泊面积变化都较大。本文利用时相为1975、2000、2007、2017年的卫星遥感影像作为基本信息源,借助GIS技术,调查研究了湖北省湖泊现状及变化情况。结果表明,2017年,湖北省域大、小天然湖泊共计808个(其中大于100 km2的湖泊有4个),湖泊总面积(平水位)2 776.96 km2,湖泊面积总量大,数量多,但空间分布极度不匀;1975-2017年的40余年间,湖泊总面积共减少了129.88 km2,年平均减少量为3.09 km2;湖泊变化阶段性特征突出,前30余年湖泊面积消减,数量减少,后10年面积增加,数量增加,反映出近10年来湖泊湿地生态环境总体趋于良性演化。 相似文献
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中国过去2000年湖泊沉积记录的高分辨率研究:现状与问题 总被引：22，自引：1，他引：22
过去２ｋａ地球环境的变化规律和原因是全球变化研究的关键内容之一，与其它自然记录相比，湖泊沉积具有储存信息量大，时间分辨率高和地理覆盖面广的优势。中国８０年代后期以来已陆续开展了全新世湖泊沉积与气候，环境演化研究，并有迅速发展之势，对于过去２ｋａ湖泊沉积的高分辨率研究，需要重视以下几方面问题，即提高核素测年的精度，建立环境指标的转换函数，注意早期化学成岩作用，选择分层湖和年层沉积，探讨气候要素有效指 相似文献
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青藏高原古近纪—新近纪古湖泊的特征及分布 总被引：4，自引：1，他引：4
通过野外地质调查,结合前人资料和遥感影像解译,对青藏高原古近纪-新近纪湖相地层进行了划分与对比,确定了湖相地层的地域分布.根据古近纪-新近纪湖相地层的展布范围,初步圈定出了63个古湖泊,划分出5个成湖阶段、13个成湖期,其统计总面积大于200×104km2.古湖泊的规模、形态、展布方向明显受构造和古地理的制约.研究表明,古近纪时期的古湖泊主要分布在高原的东北部地区,新近纪时期的古湖泊主要分布在高原的西南部地区,两者之间为过渡地带.青藏高原古近纪-新近纪古湖泊的演化,从时间上讲,有从老到新面积逐渐加大的趋势;从迁移方向上讲,有古湖泊的湖相沉积由东北向西南方向逐渐迁移、古湖泊的年龄由老变新的规律. 相似文献
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基于1∶10万与1∶50万地形图,考察了青藏高原的山地湖泊及其流域的河流(水文)、雪线、冰川高度、各高度山地面积与湖泊面积之间的关系。高原湖泊的规模与流域山地(其高度,中、西部湖拔大于500～750m,东部大于250m)存在密切关系。揭示山地降水是湖泊水的主要来源,其质(低温)与量是维持湖泊一定规模与稳定存在的主要因素。由于山地湖泊存在这种特殊的水文特点,因此,地质历史时期的暖湿期,高原山地湖泊比之低地、丘陵湖泊,扩涨规模可能更为显著。40～23kaB.P,高原山地湖泊异乎寻常地扩涨,可能是降水在暖期季风雨增加时,在山地区增高更甚,更多的低温水流贮湖泊造成的。 相似文献
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箕状湖盆萎缩阶段两种湖泊三角洲的沉积特征及成因探讨--以平庄、铁法盆地为例 总被引：7，自引：0，他引：7
以平庄、铁法盆地为例，首先阐述了箕状湖盆萎缩阶段的河口坝型湖泊三角洲发育于盆缘断裂一侧的扇前河流入湖的湖缘带，具有与海岸河控三角洲相似的沉积特征；Gilbert 型湖泊三角洲发育于沉积-侵蚀盆缘一侧河流入湖的湖缘带，具有由底积层、前积层、顶积层构成的垂向层序及朵状平面砂体形态，它与扇体没有成因联系和空间上的毗邻关系。在此基础上，论述了这两种湖泊三角洲形成的地质背景，并对它们的发育条件及进积方式等成因问题进行了较深入的探讨。 相似文献
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硫循环的酶促反应机制及湖泊环境效应 总被引：4，自引：1，他引：3
在湖泊沉积物表层存在着强烈的生物作用,使ＳＯ＾２－４转变成Ｓ＾２－,然后和Ｆｅ＾２＋结合而固定在沉积物中,这种ＳＯ＾２－４的清除机制具有重要的环境意义。本文论述了Ｈ２Ｓ的产生和各种形态硫转变成ＳＯ＾２－４的酶促反应机制,并阐述了不同微生物电子传递载体、最终电子受体和电子进入传递链的部位的差异以及生成ＡＴＰ的数目和环境效应的差异。 相似文献
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用湖泊沉积研究过去气候变化 总被引：6，自引：0，他引：6
湖泊沉积是一种具高分辨率的自然档案，记载了丰富的过去气候变迁信息；研究湖泊沉积，从中提取气候代用指标，可以恢复区域过去气候变迁史，进而推断过去全球气候变化。评述了目前研究和应用较多的十几种气候代用指标，如孢粉、碳和氧同位素、微体化石、分子化合物、碳酸钙含量、有机碳含量、藻类、沉积物粒径、矿物组合等；指出了当前特别重要的是要对各种气候代用指标的形成及其变化过程、气候代用指标的具体环境意义作深入细致的 相似文献
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记述了Ｇｅ湖的基本特征,讨论了全新世镇江海侵对Ｇｅ湖的影响,根据全新世各时期沉积物的分布,阐明了Ｇｅ湖湖岸的变化,依据古生物与人类活动遗迹资料,指出Ｇｅ湖演化发展可分为３个阶段,即距今１００００ａ～６０００ａ为雏现阶段,距今６０００ａ～２０００ａ为发展阶段,距今２０００ａ以来现代Ｇｅ湖成形阶段,究其成因为新构造活动－河道淤塞－人工改造而成。 相似文献
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Comprehensive evaluation of heavy metal contamination in surface and core sediments of Taihu Lake, the third largest freshwater lake in China 总被引：5，自引：2，他引：3
Enfeng Liu Gavin F. Birch Ji Shen Hezhong Yuan Enlou Zhang Yanmin Cao 《Environmental Earth Sciences》2012,67(1):39-51
The spatial and temporal variations of Fe, K, Co, V, Cr, Cu, Ni, Zn, and Pb were determined in the sediments of Taihu Lake, the third largest freshwater lake in China and categorized into natural origin (Fe, K, Co, and V) and human contamination (Cr, Cu, Ni, Zn, and Pb) groups by principal component analysis. Most of the metals were positively correlated with the clay content (<4???m) and negatively correlated with the >16???m fraction, indicating the dominant role of grain size in regulating metals concentrations. Geochemical normalization and enrichment factors (EFs) were introduced to reduce the confounding of variable grain size and to quantify anthropogenic contributions. Higher EF values for Cr, Cu, Ni, and Zn occurred in the north Zhushan, Meiliang, and Gonghu Bays, indicating a high level of human contamination from the northern cities, such as Wuxi and Changzhou. Higher EF values of Pb were also present in the southwest and east lake areas, denoting the existence of additional anthropogenic sources. Chrome, Cu, Ni, Zn, and Pb showed increasing EF values in the top layers of sediment cores, indicating enhancing contamination since 1970s with rapid economy development in the catchment. These results indicate that geochemical normalization is a necessary and effective method in quantifying heavy metals contamination, and that historic sediment should be used as background values in calculating EFs. Potential risks of the heavy metals were assessed linking the consensus-based sediment quality guidelines and human contamination. Concentrations of Ni and Cr are greater than the threshold effect concentration (TEC) values, even in the sediments before 1970s, due to higher background concentrations in terrestrial parent materials. Concentrations of Ni and Cr are generally lower than the probable effect concentration (PEC) values, and concentrations of Cu and Zn are below the TEC values in the open lake areas. Whereas, concentrations of Ni and Cr are surpassing the PEC values and Cu and Zn are surpassing the TEC values in the north bays due to the high level of human contamination, where they were with EFs over 1.2, denoting higher potential eco-risks. 相似文献
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内海湾底泥沉积物的环境质量状况与水生生物的生存和人体健康关系密切。在广东汕头市内海湾两岸23个点位采集了表层(0~20 cm)和深层(100~120 cm)底泥沉积物样品46件,对其pH值和Cd、Hg、As、Pb、Cr、Cu、Zn计7项重金属及K含量进行测试分析,调查底泥中这些重金属的含量特征,并参照农用地水田土壤污染风险管控标准对重金属环境污染质量进行评价。结果表明汕头内海湾底泥沉积物的pH介于7.00~8.82之间,平均值为7.83,在46件样品中41件样品的pH值大于7.5。内海湾底泥中7项重金属元素的含量均明显低于环境污染风险管制值,即对该区底泥重金属环境污染不需要管制。Cd、As、Pb、Cr这4项重金属含量均低于污染风险筛选值,其污染风险可以忽略。2件表层样品的Hg含量值高于污染风险筛选值,18件样品的Cu和Zn含量值高于污染风险筛选值,因此建议对底泥中Cu、Zn、Hg含量进行环境质量监测。K含量介于0.70%~2.59%,平均值为1.54%。基于表层底泥和深层底泥元素含量对比分析,认为该区Hg污染来源应为人为源;Cu、Zn的污染来源一部分为人为源,另一部分可能为人为源、自然源或二者的混合源。 相似文献
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T. Thangaradjou Pon Subhashini S. Raja E. Dilipan E. P. Nobi 《Environmental Earth Sciences》2014,71(3):1135-1146
Surface sediments of nine islands of Lakshadweep were evaluated for their heavy metal concentration (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn). Sediments of thirteen seagrass and seven non seagrass sites were collected randomly and analysed for heavy metal concentration using Inductively Coupled Plasma Optical Emission Spectrometer. Heavy metals like Cu, Ni and Zn were found in higher concentrations in the seagrass sediments, whereas other heavy metals such as Cd, Co, Cr, Fe, Mn and Pb were higher in non seagrass sediments. Different pollution indices were calculated to evaluate contamination level of all heavy metals in the sediments. Cadmium recorded higher contamination factor (1.733–21.067), enrichment factor (276.10–12,270) and Geo-accumulation Index (0.208–3.811) both in seagrass and nonseagrass sediments. Multivariate statistical analysis such as principal component analysis and cluster analysis coupled together with correlation co-efficient was used to identify the possible sources of heavy metal pollution in the region. Average concentrations of Cd in Lakshadweep islands were slightly higher than effective range, low but still below effective range medium. All other metals were still below these ranges indicating fairly uncontaminated sediment in the region. 相似文献
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Xiao-Hu Li Zhong-Li Tang Feng-You Chu Ling-Yuan Yang 《Environmental Earth Sciences》2011,64(6):1667-1674
Heavy metal contamination was the main environmental problem around the Jinchang Ni–Cu mine area of Gansu, Northwest China.
The concentration of heavy metals (Cr, Cu, Ni, Pb, and Zn) in various environmental mediums around the Jinchang Ni–Cu mine
area were analyzed using atomic absorption spectrometry (AAS). The different chemical speciation of heavy metals was extracted
using BCR (European Community Bureau of Reference) sequential extraction procedure, and the concentration of chemical speciation
of each heavy metal was measured by inductively coupled plasma-atomic emission spectrometry. The results showed that Cu and
Ni were the most important heavy metal pollutants in various mediums including cultivated soils, dust on slagheap surfaces,
tailings, and sediments in waste water drains. In the tailings and sediments, the concentrations of Ni were obviously higher
than those of Cu, whereas, in the soil and dust, the concentrations of Cu were higher than those of Ni. Analysis of chemical
speciation indicated that Cr and Zn were mainly in residual fraction; Cu was mainly in oxidizable fraction; Ni was mainly
in reducible fraction and acid soluble fraction; and Pb was mainly in reducible fraction and residual fraction. The extent
of contamination of various environmental mediums was different because the heavy metals were derived from different sources.
Furthermore, the mobility of various heavy metals was different because of the different distribution of chemical speciation. 相似文献
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S. Venkatramanan T. Ramkumar I. Anithamary S. Vasudevan 《Arabian Journal of Geosciences》2014,7(1):123-130
Surface sediments collected at the Tirumalairajan river estuary and their surrounding coastal areas were analyzed for the bulk metal concentration. The sediments were collected from post- and premonsoon seasons. Dominances of heavy metals are in the following order: Fe > Mn > Zn > Pb > Cu in both seasons from estuary and coastal area. The results reveal that Fe, Mn, Cu, Pb, and Zn demonstrated an increased pattern from the estuary when compared to the coastal area. The heavy metal pattern of the sediments of the Tirumalairajan river estuary and its surrounding coastal area offered strong evidence that the coastal area was a major source of heavy metals to the estuarine region. For various metals, the contamination factor and geoaccumulation index (I geo) have been calculated to assess the degree of pollution in sediments. The contamination factor and geoaccumulation index show that Zn, Pb, and Cu unpolluted to moderately pollute the sediments in estuarine part. This study shows the major sources of metal contamination in catchment and anthropogenic ones, such as agriculture runoff, discharge of industrial wastewater, and municipal sewage through the estuary and adjoining coastal area. 相似文献
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Narendra Kumar Meena M. Prakasam Ravi Bhushan Sudipta Sarkar Pranaya Diwate Upasana Banerji 《Environmental Earth Sciences》2017,76(1):39
The lakes of the Himalaya are degrading due to increase in toxic heavy metal loading. This study reports the last 50-year heavy metal pollution loading in the Rewalsar Lake, Himachal Pradesh, India. Sediment cores were recovered to study the pollution loading in the lake sediments. The 137Cs and 210Pb isotope-based sedimentation rate suggest rapid sedimentation in the lake during the last ~50 years. The concentrations of Mn, Cu, Zn, Cd, Pb, Co, Ni, Cr metals in the lake sediments owe its contributions both to the natural and anthropogenic sources. Prior to ca 1990 AD, metal loading was dominated by the lithogenic input, whereas post ca 1990 AD the metal loading was controlled by the anthropogenic factors. The Pb concentration in the lake gradually increased during 1990–2004 and then decreased significantly till present. The higher concentration of Pb seems to be derived from the fossil fuel burning, while the Cr concentration in the lake indicates the use of fertilizer in the catchment area. The lowest concentrations of elements around ca 1990 AD seem to have occurred due to channelization of the lake feeding system. 相似文献
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近50年来抚仙湖重金属污染的沉积记录* 总被引：15，自引：8，他引：15
文章以抚仙湖污染严重的北部和基本未受人类活动影响的中部为研究对象,分别采集了沉积岩芯FB和FZ,通过对岩芯的137 Cs测年和重金属元素(Cu,Ni,Ti,Cr,V,Pb,Cd和Zn)的含量分析,研究了湖泊重金属来源和污染历史,并利用地质累积指数法评价了湖泊重金属污染程度。结果表明:抚仙湖北部的平均沉积速率约为2.0~2.8mm/a;20世纪80年代以前,湖泊北部和中部的重金属元素(Cu,Ni,Ti,V,Pb,Cd,Zn)以自然来源为主;80年代以后,抚仙湖受到人类活动的影响,但湖泊中部Cu,Ni,Ti,V,Pb,Zn以及湖泊北部Cu,Ni,Ti,V仍以自然来源为主;湖泊北部Pb和Zn地质累积指数值小于1,属无污染到中度污染;北部Cd地质累积指数为3~4,达强度污染;中部Cd地质累积指数为2~3,属中强度污染;且Pb,Zn和Cd污染程度有加速增大的趋势。 相似文献
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太湖MS岩芯重金属元素地球化学形态研究 总被引：21，自引：4，他引：17
采用BCR三步提取法对太湖MS岩芯沉积物中Cu、Fe、Mn、Ni、Pb和Zn等6种重金属元素的化学形态进行了研究.结果表明,有效结合态的Cu、Ni和Pb主要以有机物及硫化物结合态、Fe-Mn氧化物结合态存在,Fe和Zn主要以Fe-Mn氧化物结合态存在,Mn主要以可交换态及碳酸盐结合态存在;Fe-Mn氧化物结合态的Ni、Pb和Zn与可还原态的Mn有较好的正相关关系,有机物及硫化物结合态的Cu、Mn、Ni、Pb和Zn与有机碳含量有较好的正相关关系;重金属形态分布体现了重金属元素地球化学性质的差异,以及重金属形态含量与沉积物理化性质的关系.沉积岩芯重金属元素形态垂向变化规律及次生相富集系数表明,Cu、Mn、Ni、Pb和Zn在沉积岩芯13～4 cm有效结合态含量较稳定,为自然沉积;4～0 cm有效结合态含量明显升高,存在一定程度的人为污染.根据137Cs测年结果判断,沉积岩芯Cu、Mn、Ni、Pb和Zn等重金属污染开始于20世纪70年代末期,主要污染元素及污染历史与太湖流域污染工业类型及经济发展阶段相吻合. 相似文献
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武汉市墨水湖沉积物重金属污染特征与防治对策 总被引：8，自引：2，他引：8
武汉市墨水湖重金属污染严重,其污染特征在我国城市湖泊中具代表性。在对墨水湖不同湖区沉积物中重金属污染物空间分布特征进行分析的基础上,应用地积累指数法探讨不同重金属元素含量随深度变化的规律和原因,并对墨水湖沉积物中重金属的污染程度进行评价表明:墨水湖沉积物中重金属元素锌和汞污染最为严重,污染程度由高到低依次为:Zn>Hg>Cu>C r>Pb>A s;从整个湖区来看,分布有排污口的周边湖区污染严重,湖心污染程度较低;沉积物中主要重金属元素含量随深度增加而降低,其变化规律主要受污染状况的影响,沉积物颗粒粒径的变化和早期成岩作用的影响不大。为了改善墨水湖水质条件和重金属污染严重的现状,必须在截污、疏浚和引水工程等基本治理措施保护下,重建和恢复沉水植物系统,才能从根本上改善湖泊水质。 相似文献