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1.
The Dongting Lake, the second biggest freshwater lake in China, consists of three wetlands of national importance, namely the East Dongting Lake, the South Dongting Lake, and the West Dongting Lake. Surface sedi-ments were sampled from 57 locations across the lake. Nutrient concentrations [total organic carbon (TOC), total N (TN) and total P (TP)] and 16 element concentrations (Al, As, B, Ca, Cd, Cr, Cu, K, Fe, Hg, Mn, Ni, Pb, Si, Ti and Zn) in the sediments were measured to investigate the impact of industrialization along the lake's coastline and sev-eral tributaries on the profiles of nutrients and heavy metals in the lake's surface sediments. R-mode cluster analysis (CA) was used to integrate geochemical data. The result showed that euthophication of the Dongting Lake resulted mainly from TN and TOC. The main polluting trace metals are Hg, As, Cd, Zn, Pb and Mn, which are largely ad-sorbed on clay minerals or Fe/Mn oxides, or deposited as carbonates. Principal component analysis (PCA) revealed the source of micropollutants. The worst affected district by heavy metals is the East Dongting Lake, the pollution sources may originate mainly from the Xiangjiang drainage area. The results demonstrated that multivariate methods are the potentially great tools for the interpretation of the environmental data on lake sediments.  相似文献   

2.
In order to assess the pollution levels of selected heavy metals, 45 bottom sediment samples were collected from Al-Kharrar lagoon in central western Saudi Arabia. The concentrations of the heavy metals were recorded using inductively coupled plasma-mass spectrometer (ICP-MS). The results showed that the concentrations of Pb and Cd exceeded the environmental background values. However, the heavy metal contents were less than the threshold effect level (TEL) limit. The concentrations of heavy metals in lagoon bottom sediments varied spatially, but their variations showed similar trends. Elevated levels of metals were observed in the northern and southern parts of the lagoon. Evaluation of contamination levels by the sediment quality guidelines (SQG) of the US-EPA revealed that sediments were non-polluted-moderately to heavily polluted with Pb; non-polluted to moderately polluted with Cu; and non-polluted with Mn, Zn, Cd, and Cr. The geoaccumulation index showed that lagoon sediments were unpolluted with Cd, Mn, Fe, Hg, Mo, and Se; unpolluted to moderately polluted with Zn and Co; and moderately polluted with Pb, Cr, Cu, and As. The high enrichment factor values for Pb, As, Cu, Cr, Co, and Zn (>2) indicate their anthropogenic sources, whereas the remaining elements were of natural origins consistent with their low enrichment levels. The values of CF indicate that the bottom sediments of Al-Kharrar lagoon are moderately contaminated with Mn and Pb.  相似文献   

3.
松花江上游表层沉积物中重金属元素时空分布特征   总被引：1，自引：0，他引：1  
松花江是我国七大河流之一,研究其底泥重金属元素的时空分布特征对流域的水环境治理具有重要意义。本文对松花江（哈达山至松花湖段）底泥（表层沉积物）中元素As、Hg、Cr、Cd、Pb的分布特征进行了研究,并利用地累积指数分析了这些元素的污染状况。结果表明：研究区底泥几乎未受到As、Cr和Pb的污染,但多数地段内出现了Cd和Hg的污染,尤其是元素Hg,在个别地段的污染程度达到了极强;与10年前相比,一些重金属的污染得到了明显改善,但吉林市区段内Hg的污染仍非常严重。污染样品空间分布特征表明,松花江吉林市区段可能有来自工农业废水的重金属污染。  相似文献   

4.
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  
苏春利  王焰新 《矿物岩石》2006,26(2):111-116
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   

5.
Dissolved trace elements and heavy metals of waters and sediments in the ten shallow lakes in the middle and lower reaches of the Yangtze River region were determined to identify their composition and spatial distribution, and to assess the extent of their environmentally detrimental effects by comparison with water and sediment quality guidelines. Results indicated that As and Pb were the main pollutants in lake waters and Mn and Hg the potential ones, while As, Cu and Pb were the main pollutants in lake sediments. Their spatial distribution indicated that Daye Lake was seriously polluted by metals, which was corroborated by cluster analysis. Higher concentrations of trace elements have been found in lakes downstream of the Yangtze River delta, and higher concentrations of metals have been recorded in sediments of upstream lakes, suggesting that metals in water were more sensitive to anthropogenic activities and that metals in sediment were mainly controlled by minerals. Correlation analyses demonstrated that there were stronger associations among metals in lake sediments than those in lake waters, and their good relationships suggested the common sources. Further research on the subject will help develop water quality management with the aim of restoring shallow lakes in the Yangtze River.  相似文献   

6.
The BCR sequential extraction procedure is applied to probe into the speciation distribution of heavy metals (Cd, Cr, Zn, Cu and Pb) in lake sediments of Core XJ2 in Xijiu Lake, Taihu Lake catchment, China. The results showed that the effective species concentration of this five heavy metal elements increased obviously during the past century, the proportions of organic/sulphide fractions of Zn, Cu and Pb decreased while the Fe–Mn oxide fractions increased, and the proportion of Fe–Mn oxide fractions of Cd decreased while the exchangeable and carbonate fractions increased. The concentrations of exchangeable and carbonate fractions of these five elements were increased in the past century, especially the proportions of these fractions of Cd, Zn, Cu and Pb increased prominently. These changes could be attributed to the anthropogenic pollution. Since the changes of the heavy metal concentrations were corresponding to the history of human activities, especially the industry development, within the catchment.  相似文献   

7.
太湖沉积物重金属及营养盐污染研究   总被引：26，自引：1，他引：25  
通过太湖MS沉积岩芯元素地球化学指标的分析,对太湖沉积物污染历史进行了系统的讨论。根据化学元素的聚类分析结果、变化趋势,并与太湖流域经济发展进程对比,认为太湖沉积物铅、锌、锰、镍污染开始于20世纪70年代末期,砷、汞污染分别开始于30年代和40年代,随着底泥重金属污染程度的加重,沉积物表层磁化率明显升高;总磷自40年代以来含量不断增加,总氮、总有机碳含量增加开始于70年代末期,表明湖泊富营养化程度不断加重。太湖沉积物重金属及营养盐污染历史与该区经济发展阶段相吻合。  相似文献   

8.
以金矿开发影响的黄河二级支流太峪水系沉积物为研究对象,沿河采集16个表层沉积物样品,分层采集垂向剖面10件水库沉积物样品,测定了样品中重金属元素Hg、Pb、Cd、Cr、As、Cu和Zn的含量,采用Hakanson潜在生态指数法和Tomlinson污染负荷指数法评价重金属元素污染程度和潜在生态风险。结果表明,矿业活动是太峪水系沉积物重金属元素污染的主要因素;变异系数、富集系数和最高污染系数均反映Hg、Pb、Cd是太峪水系沉积物的特征污染重金属元素,Cr和As的质量分数接近地区背景值;太峪水系表层沉积物受到重金属元素的极强污染,山区段污染较山外更严重;整个流域的Hg、Pb、Cd具有很强的潜在生态危害,Cr、As、Zn的潜在生态危害轻微;太峪水系沉积物垂向各层沉积物都受到重金属元素的极强污染,生态问题以Hg、Pb、Cd的潜在生态危害为主,其污染和生态危害程度都高于流向上的沉积物。潜在生态危害指数评价突出了不同元素的毒性和危害程度,而污染负荷指数法侧重于样本空间上的污染程度,二者互补使用有利于实际问题的全面评价。  相似文献   

9.
The Nansi Lake has been seriously affected by long-term intensive industrial and urban activities. The objectives of this study were to determine the content, distribution, and ecological risk of arsenic and investigate the geochemical relationships between arsenic forms and sediment mineral phases of the Nansi Lake. Twenty samples of surface sediments were collected and analyzed for arsenic contents and chemical forms. Results indicated that total content of arsenic in the sediment samples averaged 13.45?mg/kg and ranged from 8.27 to 21.75?mg/kg. The arsenic was mostly associated with iron oxides (67.3%), followed by the association with the residual fraction (19.2%). In addition, total content of arsenic was positively correlated with the organic matter and iron contents in the sediment. The molar ratios of iron oxide bound arsenic content to iron content are lower than the maximal molar ratios of arsenic to iron for natural hematite, magnetite, and goethite. The total content of arsenic in the sediment samples was usually higher than threshold effect concentration of 9.79?mg/kg, but lower than probable effect concentration of 33.0?mg/kg for arsenic in freshwater sediments. Adverse effects or toxicity to the aquatic organisms, caused by arsenic in the sediments of the Nansi Lake, will likely occur at these levels of arsenic contamination.  相似文献   

10.
太湖沉积物微量元素特征和变化：自然与人类活动的影响   总被引：7，自引：1，他引：7  
通过对太湖沉积物微量元素的测定，分析了沉积物的元素含量特征及变化趋势，指出了重金属元素的分布特点。沉积物和岩石微量元素的上地壳标准化值显示，它们的曲线存在明显的区别，反映了物质在风化和沉积过程中不同的性质差异。重金属在太湖北部地区较高，在南部地区较低，特别是As、Hg、Cu、Zn、Ni。对照背景值，探讨了重金属元素的富集程度，并运用地累积指数评估了沉积物的污染程度。根据1987年和2000年的数据，计算了重金属的累积速率。最后，讨论了自然作用和人类活动对微量元素的影响。  相似文献   

11.
Core and surface sediments from the Tonalli River, a tributary of the artificial lake, Lake Burragorang, in the Blue Mountains National Park, New South Wales, Australia, were studied to evaluate the spatio-temporal distribution of pollutants from the Yerranderie silver-lead-zinc mine site, abandoned in the late 1920s. A sediment core was collected in the mouth of the Tonalli River, at its junction with Lake Burragorang, and surface sediment samples were collected in the Tonalli River and its tributaries. The concentrations of Pb, As, Zn, Cu, Cd, Hg and Ag in the sediments were determined by ICP-MS and ICP-AES techniques. Temporal variability of metal concentrations was established through 210Pb dating of the core sediments and compared with published historical records, rainfall records and bushfire data. Metal concentrations in core sediments showed an overall increase around the year 1950 as well as increases coincident with heavy rainfall. Spatially, metal concentrations were up to 400 times the guideline limit around mine sites but decreased rapidly with distance downstream of the mines.  相似文献   

12.
Sequential core sediments from northwestern Taihu Lake in China were analyzed for grain size, organic carbon and heavy metal content. The sediments are composed of organic-poor clayey-fine silts. The chemical speciations of Cu, Fe, Mn, Ni, Pb, and Zn were also analyzed using the BCR sequential extraction procedure. Cu, Fe, Ni, and Zn are mainly associated with the residue fraction; Mn is concentrated mainly in exchangeable/carbonate fraction and residue fraction; and Pb mainly in Fe/Mn oxide fraction and organic/sulfide fraction. The exchangeable/carbonate fractions of Cu, Fe, Ni, Zn and Pb are lower. The fractions of Ni, Pb and Zn bound to the Fe/Mn oxide have significant correlations with reducible Mn; the organic/sulfide fractions of Cu, Mn, Ni, Pb, and Zn have significant correlations with TOC. The extractable fractions of Cu, Mn, Ni, Pb, and Zn are high at the top 4 cm of the core sediments as compared to those in the deeper layers, showing the anthropogenic input of heavy metals is due to rapid industrial development. The heavy metal pollution history of the sediments has been recorded since the late 1970s, determined by the result of ^137Cs dating.  相似文献   

13.
The present study investigates the anthropogenic metal input into the lake system, the toxic metal pollution in the sediments of Kodaikanal Lake. Surface sediment samples were collected at seven locations to represent its spatial variability within the lake. Samples were subjected to analyze for Fe, Co, Cr, Mn, Ni, Zn, Cd, Cu, Ag, Pb, Hg, and As by energy dispersive X-ray fluorescence (EDXRF) and their concentrations in lake sediments range from 102,000–109,000, 561–2699, 292–544, 211–482, 79–163, 57–265, 57–74, 37–92, 46–59, 20–97, 19–30, to 13–24 mg/kg, respectively. The sources of pollution were inferred through spatial and statistical analyses. Most of the toxic metal contents in the sediments are found to exceed the background concentration in all locations. The enrichment factor (EF) and index of geoaccumulation (I geo) of Hg, Co, Cd, and Ag showed that sediments of Kodaikanal Lake exhibit the probability of anthropogenic influence. The significant Pearson’s correlation coefficient is also suggesting that they probably originated from the same source of occurrence. The contamination factor and degree of contamination of the Kodaikanal Lake sediments are strongly polluted in terms of most of the examined metals. The study also provides environmentally significant information about anthropogenic influence on the lake sediments.  相似文献   

14.
The understanding of the solid-phase speciation of arsenic in soils and sediments is important in the evaluations of its potential mobility and availability in the environment. The spoil heaps of abandoned mercury mines contain waste materials with high arsenic and heavy metals concentrations. The weathering of these tailings can cause their mobilization to the surroundings. In this work, the mobility and availability of arsenic and some heavy metals were evaluated in sediments from two heavily polluted mercury mining districts in Asturias (NW Spain). For this purpose, a slightly modified version of the Bureau Community of Reference sequential extraction scheme was applied to sediments. The total contents in the operationally defined fractions were analysed by inductively coupled plasma-atomic emission spectrometry. Extremely high total arsenic concentrations were found in all sediments ranging from 4,000 to 24,800 mg kg?1. High easily mobilizable arsenic contents were found in the first mining area, related to the solubilization of Ca-bearing phases, supported by extracts analyses, X-ray diffraction results and the positive correlation found among the As and Ca fractionations. Ni and Zn were the most mobile among heavy metals, being Cr the least mobile, suggesting an anthropogenic origin due to the metallurgical processes, transport or dispersion generated from neighbour spoil heaps. In the second mining area, the bulk of As was concentrated in the residual phase, as well as Cr, Cu, Fe, Pb, Ti, indicating a mineralogical origin and the low availability of these elements. The strong correlations established between As and Fe and Ti distributions support the hypothesis that As is mainly associated to structural mineral phases in these sediments.  相似文献   

15.
金鹏  祁超  郭炳跃 《江苏地质》2023,47(4):420-427
为查清高邮湖底泥及出入湖河口表层沉积物重金属分布特征,评价其潜在生态风险,以湖区及周边25个底泥和沉积物样品为载体,重点研究8种重金属元素,选用单因子污染指数法、内梅罗综合指数法、地累积指数法和潜在生态风险指数法,相似比对重金属污染等级及评价潜在生态风险。测试数据表明,8种重金属元素中,仅Hg含量（平均值）未超过里下河浅洼平原表层土壤重金属元素背景值,As含量（最大值）超过农用地土壤污染风险筛选值。Pearson相关系数矩阵表明,重金属元素Ni与Cr、Pb、Zn、Cu之间具显著同源性;单因子污染指数法与内梅罗综合指数法评价结果显示,污染指数均值排序均为As＞Cd＞Pb＞Cu＞Zn＞Ni＞Cr＞Hg,但对As、Cd评价前者为轻度污染,后者为中度污染;地累积指数Igeo显示,仅As为轻度污染,其余元素均为无污染状态。沉积物单项潜在生态风险指数排序为Cd＞Hg＞As＞Pb＞Cu＞Ni＞Cr＞Zn,仅Cd属中风险,其余元素为低风险;研究区综合潜在生态风险指数RI均值为115.7,表明全区总体生态风险属于低风险状态,重金属有沿入湖河口向湖心区富集趋势。  相似文献   

16.
Sediments of the Lagoa Vermelha (Red Lake), situated in the Ribeira Valley, southeastern Brazil, are made of a homogeneous, organic-rich, black clay with no visible sedimentary structures. The inorganic geochemical record (Al, As, Ba, Br, Co,Cs, Cr, Fe, Mn, Ni, Rb, Sc, Sb, V, Zn, Hg and Pb) of the lake sediments was analyzed in a core spanning 2430 years. The largest temporal changes in trace metal contents occurred approximately within the last 180 years. Recent sediments were found to be enriched in Pb, Zn, Hg, Ni, Mn, Br and Sb (more than 2-fold increase with respect to the “natural background level”). The enhanced accumulation of Br, Sb, and Mn was attributed to biogeochemical processes and diagenesis. On the other hand, the anomalous concentrations of Pb, Zn, Hg and Ni were attributed to pollution. As Lagoa Vermelha is located in a relatively pristine area, far removed from direct contamination sources, the increased metal contents of surface sediments most likely resulted from atmospheric fallout. Stable Pb isotopes provided additional evidence for anthropogenic contamination. The shift of 206Pb/207Pb ratios toward decreasing values in the increasingly younger sediments is consistent with an increasing contribution of airborne anthropogenic lead. In the uppermost sediments (0-10 cm), the lowest values of the 206Pb/207Pb ratios may reflect the influence of the less radiogenic Pb from the Ribeira Valley District ores (206Pb/207Pb between 1.04 and 1.10), emitted during the last 50 years.  相似文献   

17.
Following recent concerns of chemical pollution around Lake Naivasha, especially originating from recent agricultural activities in the catchment, samples of water, sediments, and fish Common carp (Cyprinus carpio) were collected from the Hippo Point, Kasarani, Mouth of Malewa River, Mouth of Karati River, Crescent Island, Sher Karuturi Discharge outlet and Oserian Bay for analysis of Cu, Cd and Pb by FAAS. The mean heavy metal levels ranged from 5.12?C58.11 (Pb), 1.06?C1.73 (Cd), and <0.03?C2.29 (Cu) mg/kg wet weight in C. carpio muscle, <100?C179.83 (Pb), <10.00?C10.06 (Cd) and <30.00?C32.33 (Cu) ??g/L in surface water, and 17.11?C53.07 (Pb), 1.18?C5.58 (Cd) and 3.00?C8.48 (Cu) mg/kg dry weight in sediment and showed a wide variation within and between samples with relatively high concentrations in sediments and fish muscle tissues. The results indicate that Lake Naivasha, in some parts, is polluted with these heavy metals of which relatively higher concentrations are found at the discharge outlets near Sher Karuturi and Oserian Bay. This indicates possible contribution from surrounding horticultural/floricultural activities and the Mouths of the Rivers Malewa and Karati which flow from it??s upper catchment.  相似文献   

18.
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   

19.
 An evaluation of the influence of channel processes (erosion, accumulation, processing of channel sediments) on the dispersal of heavy metals in bottom sediments was carried out in the channels of the Sztoła and Biała Przemsza rivers in Upper Silesia, Poland. These rivers receive waters from a Zn and Pb mine. Mine waters transport a large amount of fine-grained sediments contaminated with heavy metals. The polluted material is accumulated in these stream courses and mixed with nearly homogeneous sandy sediment derived from erosion of the river banks and bed. Because these alluvia are easily set in motion, the distribution of heavy metal concentration in the channel in fraction <1 mm reflects differences in physical processes of sedimentation in its cross-section. The minimal values in active channel and maximal in the near-bank zone are typical for those channel sections where heavy metals, present in a solid state, are transported as a suspended load (normally the largest part of a polluted river course). In short sections heavy metals associated with the grains of a large mass which has accumulated in the active channel are transported as a bed load and the typical distribution pattern is reversed (in fractions both <1 mm and <0.063 mm). Such regularities can be disturbed in localities where strong, turbulent flow or frequent eddying occur and Mn oxides and hydrooxides and associated elements precipitate. The smallest variation in heavy metal concentration in the homogenous, fine-grained bank sediments which are trapped by plants below water level is a feature which recommends these localities as being the most suitable for monitoring of river pollution. Received: 11 November 1997 · Accepted: 12 March 1998  相似文献   

20.
In this paper210 Pb and 137Cs dating methods were used to determine sedimentation rates of lakes Dianchi, Erhai and Poyanghu, and to establish the time scale of the sediments. Also based on geochemical records in the sediment column, the historical variation in heavy metal content over the past one hundred years was determined. Some element concentration increased rapidly after the 1970s, such as Cu, Zn and Mn in the sediments of northern Lake Dianchi, Cd and Mn in southern Lake Erhai and in the west central parts of Lake Poyanghu, Our investigations indicate that the increase in element concentration is caused by human activities. In order to understand the extent of the effect caused by human activities, we have calculated the flux of Zn, Cd and Mn. Results show that the flux caused by human activities is seven times greater than the natural one and the ratio is about 2 times in Lake Erhai and Lake Poyanghu.  相似文献   

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