湘西河流表层沉积物重金属污染特征及其潜在生态毒性风险

花垣河和峒河是湘西地区受到锰矿和铅锌矿生产影响严重的两条河流。通过表层沉积物采样分析了Cd、Pb、Cu、Ni、Cr、Zn和Mn的总量,根据BCR连续提取程序分析沉积物样品中重金属的地球化学赋存形态,采用内梅罗指数法和地积累指数法评价了沉积物重金属污染特征,根据重金属的富集程度探讨了重金属污染来源,采用淡水生态系统沉积物质量基准(SQGs,TEL/PEL)和毒性单位评价了花垣河和峒河沉积物中重金属元素的生态毒性风险。结果表明,花垣河和峒河绝大多数位点的表层沉积物中Cd、Pb、Cu、Ni、Cr、Zn和Mn的总量高于参照点,形成严重的复合污染,花垣河沉积物中重金属的污染水平明显高于峒河,但沿程变化规律不明显,而峒河沉积物中重金属的沿程变化较有规律,即上游含量低,中下游含量较高。两条河流表层沉积物中富集程度居前列的均为Cd、Pb、Zn和Mn。花垣河和峒河沉积物重金属污染主要来源于矿业生产所产生废渣和废水的点排放。在花垣河和峒河的大多数位点,Cd、Pb和Mn的形态具有共同特征,其生物可利用态均较大程度地超过生物不可利用态,而且Mn和Cd的生物可直接利用态所占比例远高于其它重金属,而Cu和Cr的生物可直接利用态所占比例很低。花垣河沉积物中Cd、Pb和Zn在所有位点极大地超过PEL,在峒河中下游,Cd、Pb、Ni和Zn超过PEL,具有较大的潜在生物毒性。除上游S1位点外,花垣河的其余各位点都具有明显的急性毒性,峒河中下游各位点具有明显的急性毒性,这些河段需要重点治理。     

惠州市3座供水水库沉积物重金属污染特征

为了解惠州市供水水库沉积物重金属(Cr、Cu、Zn、Cd、Pb和Hg)污染状况和垂直分布特征,于2008年5月在惠州市3座具代表性的水库湖泊区采集柱状沉积物样品,运用ICPMS法检测沉积物中重金属含量,并采用地积累指数法(Igen)和潜在生态风险指数法(RI)进行污染评价,同时运用主成分分析(PCA)对沉积物中重金属的可能来源进行分析.结果表明:3座水库沉积物重金属含量随沉积深度的变化差异明显,一些重金属含量的垂直变化不明显,而另一些垂直变化明显(降低或升高),但各种重金属在不同水库沉积物中呈现特有的垂直分布特征.根据地积累指数可知,3座水库中沉积物主要以Zn和Pb污染最为严重,达到轻度至强度污染(含量分别为Zn:49.98 ～ 640.29 mg·kg-1;Pb:21.94～300.66 mg· kg-1),同时沉积物中部或底部受到轻度的Cu污染(含量为16.85 ～45.46 mg·kg-1),基本未受Cr、Cd和Hg污染.据6种重金属潜在生态风险系数[Er(i)]及潜在生态风险指数(RI)可知,3座水库沉积物的重金属潜在风险均处于较低水平.据PCA分析和相关资料可知,矿山开采与冶炼、城市化和农林业快速发展等人类活动影响了3座水库沉积物重金属的分布特征和污染.其中,Zn主要来源于矿产开采与冶炼;除矿产开采与冶炼导致沙田水库Pb污染外,机动车尾气排放和生活垃圾等是3座水库沉积物Pb污染的主要途径;Cu污染主要来源于农业和林业污染.     

The Concentration and Partitioning of Heavy Metals in Surface Sediments of the Maharlu Lake,SW Iran

In this study, an assessment is made of the environmental impacts of heavy metal concentration and fractionation in bed sediments of the saline Maharlu Lake, SW Iran. Total elemental analysis indicated that sediments were highly enriched in Pb and Cd. Sequential extraction analysis revealed that salt of the lake is probably highly contaminated with Cd, Pb, and Co. Due to the oxidizing conditions of the lake, the organic matter fraction of the elements was not significant. In all sediments, Cd, Pb, Co, Mn, and Zn were strongly associated with exchangeable plus carbonate fractions, with mean percentage of 76.4%, 65.3%, 56%, 40.9%, and 34.3%, respectively. On average, the percentage of Ni associated with the sum of the exchangeable and carbonate fractions was 19.8%. Cr, Fe, and Cu fractionation indicated that these metals are environmentally inert and immobile. Statistical relationships among metal fractions and sediment properties showed that Cd, Pb, Zn, Ni, Co, and Mn were mainly from recent anthropogenic sources, while such sources were less important for Cr, Cu, and Fe. The latter metals represented natural geochemical levels.     

湖南省主要水系底泥重金属污染特征及其生态风险评价

为全面了解湖南省主要水系底泥中重金属含量及其潜在生态风险,在湖南省内的湘、资、沅、澧以及洞庭湖5个主要水系共采集了75个位点的底泥样品,分析了重金属元素含量和来源分布特征,并采用地累积指数法、内梅罗指数法和潜在生态风险指数法对其污染程度和潜在生态风险进行评价。结果表明,As、Cd、Cr、Cu、Mn、Pb和Zn的平均含量分别为32.87、7.59、78.09、70.69、1182.60、85.64 mg/kg和482.44 mg/kg。湘江和洞庭湖的污染相对严重,底泥中重金属含量明显高于资江、沅江和澧水;相关性分析表明多种重金属具有相同污染来源;地累积指数评价结果显示,湖南省主要水系底泥中Cd为重污染水平,Zn为中度污染,Cu、Mn和Pb均为轻度污染,而As和Cr污染程度为清洁;内梅罗指数法评价结果表明,除Cr为轻度污染外,湖南省主要水系底泥中其他6种重金属污染均为重污染级别;潜在生态风险评价结果显示,湖南省总体潜在生态风险属于中等级别,各水系潜在生态风险大小顺序为洞庭湖>资江>湘江>澧水>沅江,重金属Cd的潜在生态风险级别为很强,其他重金属元素都属于轻微级别。     

吴城鄱阳湖自然保护区鱼体重金属的富集及安全性评价

为研究吴城鄱阳湖自然保护区鱼类重金属的污染情况, 以鄱阳湖吴城6种常见淡水鱼(鲤、鳙、鲢、草鱼、青鱼、鳊)为研究对象, 分别研究鱼心脏、肝脏、鳃丝和肌肉等部位中铜、锌、铅、镉4种重金属的富集情况, 并采用目标危险系数(THQ)评价其健康风险。结果显示, 重金属元素在鱼体不同器官中的富集程度不同, Cd在肝脏中的含量最高, Cu在肝脏和心脏中的含量最高, Pb在肝脏中的富集含量最低, Zn在各器官的总体含量要高于其他3种元素。4种重金属在鱼肌肉中的含量均符合国内外标准。目标危险系数(THQ)分析结果表明, Pb导致的健康风险最高, Cd最低, 单一重金属THQ值和复合重金属TTHQ值均小于1, 说明吴城鄱阳湖自然保护区鱼类重金属的污染程度较低, 不会对消费者健康产生潜在危害。     

Total nitrogen and pH-controlled chemical speciation,bioavailability and ecological risk from Cd,Cr, Cu,Pb and Zn in the water level-fluctuating zone sediments of the Three Gorges Reservoir

We investigated the distribution and chemical speciation of Cd, Cr, Cu, Pb and Zn in the water level-fluctuating (WLF) zone of the main stream (MS) and tributaries (ZX and MX) of the Three Gorges Reservoir. We evaluated the ecological risk and pollution level from heavy metals based on the Potential Ecological Risk Index (RI), Risk Assessment Code (RAC), and Ratio of Secondary Phase and Primary Phase (RSP). Our results indicated that the total and bio-available heavy metal contents were higher in the tributaries than in the MS. Moderate pollution from Cd and light pollution from Pb were observed both at the MS and ZX sites, whereas the MX site exhibited a pattern of heavy Cd pollution and light Cr and Pb pollution. In our study area, the results indicated that Cd exhibited a higher ecological risk than did the other heavy metals. Finally, the pH and nitrogen content of sediments may play a key role in controlling the amount of heavy metal bioavailability, further inducing a higher potential ecological risk.     

Assessment of Heavy Metal Enrichment,Bioavailability, and Controlling Factors in Sediments of Taihu Lake,China

Heavy metal distribution, bioavailability, and ecological risk in the surface sediment of Taihu Lake were evaluated. Samples were collected from eight representative sites in September 2011 and February 2012. In the surface sediment, average metal contents were in the order of Cr > Zn > Ni > Pb > Cu. Spatially, Zhushan Bay maintained higher Cu, Ni, and Zn contents and Xiaomeikou maintained higher Cr and Pb contents than other sites. Spatial and temporal variation were observed in the bioavailable metals determined by acid-soluble fraction of BCR extraction. The labile metals in Zhushan Bay and Xiaomeikou were quantified by diffusive gradients in thin films (DGT) and DGT-labile concentrations of Zn, Ni, Cu, Pb, and Cd were in descending order, indicating the inconsistence of labile concentrations of different heavy metals with the total metal contents and that the toxic effect of Cd in sediment should be given attention. The ecological risk assessed by Hakanson potential ecological risk index showed that Zhushan Bay suffered the most serious pollution and should be given special attention. Bioavailability of metals should be taken into account during risk assessment for more accurate estimation.     

Heavy Metals (Cd,Cu, Ni,Pb, and Zn) Fractionation in River Sediments,Hamedan, Western Iran

Five heavy metals (Cd, Cu, Ni, Pb, and Zn) in river sediments from Abshineh River, Hamedan, western Iran, were fractionated by a sequential extraction procedure. Cu, Ni, Pb, and Zn existed in sediments mainly in residual fraction (mean 92%, 86%, 77%, and 65%, respectively), whereas Cd occurred mostly as organic matter (mean 41%) and exchangeable (mean 25%) fractions. The mean percent of mobile fraction of Cd, Cu, Ni, Pb, and Zn in contaminated sediments was 25, 13, 4, 24, and 10, respectively, which suggests that the mobility and bioavailability of the five metals in sediments probably decline in the following order: Cd = Pb > Cu > Zn > Ni. The metal levels were also evaluated according to the contamination factor, which revealed significant anthropogenic pollution of Cd and Pb.     

南四湖典型入湖河流沉积物重金属污染特征与风险评价研究

以南四湖两条典型入湖河流为研究对象,分别对湖东的泗河及湖西的东鱼河沉积物中9种重金属(Cr、Ni、Zn、Cu、Pb、Hg、Cd、As、Mn)含量进行分析,最后采用多种方法解析重金属的来源并对其污染特征和生态风险进行评价.结果表明,两条河流沉积物中重金属均存在一定程度的富集,尤其是Hg、Zn、Cd富集最严重.泗河沉积物中...     

Distribution and bioavailability of heavy metals in different particle-size fractions of sediments in Taihu Lake,China

Abstract

Taihu Lake is one of the most important water sources in the economically developed central-eastern part of China, and metal pollution is a major concern for the lake. The distribution and bioavailability of Cd, Cr, Cu, Pb, Sb and Zn were analysed in undifferentiated bottom sediments and in various particle-size fractions of the sediment from different parts of the lake. The average concentration of total metals in undifferentiated sediments ranged from 0.86 mg kg^-1 (Cd) to 95.45 mg kg^-1 (Zn) for the entire lake, with the highest concentrations in Zhushan Bay. The concentration of heavy metals was higher in extremely fine sands (0.064–0.125 mm) and fine sands (0.125–0.25 mm) than in other fractions. Sequential extractions showed that Cu, Zn and Cd were the most bioavailable accounting for 55.6%, 38.7% and 30.0% of their total concentration, respectively. However, the bioavailable proportion of many metals was not significantly different between grain grades except for Cu and Zn, which were higher in silts (<0.064 mm) than in other grades. Compared with the background values of local soils, the concentration of Zn, Cd, Cu, Pb and Sb was higher, indicating enrichment in the sediment. From ecological safety concerns, Zn, Cd and Cu should be examined closely because of their higher bioavailabilty in the sediment.     

Levels,solid-phase fractions and sources of heavy metals at site received industrial effluents: a case study

Heavy metals in the site received industrial effluents were investigated to assess the pollution levels, distribution of metal among solid-phase fractions and possible metal sources. The soil samples at different depths of 0–5, 5–25 and 25–50 cm were collected and analyzed for Fe, Mn, Cd, Zn, Cu, Ni and Pb. Among all metals, Cd content was not detected in all soil samples. The average contents of Pb and Zn are higher than the corresponding values of common range in earth crust. Meanwhile, the maximum contents of Cu and Zn are higher than those of Dutch optimum value but lower that the Dutch protection act target value. The maximum contents of Cu, Pb and Zn are higher than the average shale value. The most investigated heavy metals are mostly found in the potentially labile pool (>50.0%) including metal bound to carbonate, Fe/Mn oxides, or organically fractions. Enrichment factor (EF) in combination with multivariate analysis including principal component analysis (PCA) and hierarchical cluster analysis (HCA) suggest that Mn and Ni associated with Fe in the soil samples were primarily originated from lithogenic sources. Pb was largely derived only from anthropogenic source, while Cu and Zn in the soil samples were controlled by the mixed natural and anthropogenic sources. These results suggest that discharging the industrial effluents into dumping site increased pollution level of Pb, Zn and Cu as well as enhanced their potentially labile pool that may be responsible for occurring potential toxic impacts on environmental quality.     

Integrated assessment of heavy metal contamination in sediments from a coastal industrial basin, NE China

The purpose of this study is to investigate the current status of metal pollution of the sediments from urban-stream, estuary and Jinzhou Bay of the coastal industrial city, NE China. Forty surface sediment samples from river, estuary and bay and one sediment core from Jinzhou bay were collected and analyzed for heavy metal concentrations of Cu, Zn, Pb, Cd, Ni and Mn. The data reveals that there was a remarkable change in the contents of heavy metals among the sampling sediments, and all the mean values of heavy metal concentration were higher than the national guideline values of marine sediment quality of China (GB 18668-2002). This is one of the most polluted of the world's impacted coastal systems. Both the correlation analyses and geostatistical analyses showed that Cu, Zn, Pb and Cd have a very similar spatial pattern and come from the industrial activities, and the concentration of Mn mainly caused by natural factors. The estuary is the most polluted area with extremely high potential ecological risk; however the contamination decreased with distance seaward of the river estuary. This study clearly highlights the urgent need to make great efforts to control the industrial emission and the exceptionally severe heavy metal pollution in the coastal area, and the immediate measures should be carried out to minimize the rate of contamination, and extent of future pollution problems.     

Bioavailability and Concentration of Heavy Metals in the Sediments and Leaves of Grey Mangrove, <Emphasis Type="BoldItalic">Avicennia marina</Emphasis> (Forsk.) Vierh,in Sirik Azini Creek,Iran

The concentration and bioavailability of Ni, Cu, Cd, Zn, and Pb in the sediments and leaves of grey mangrove, Avicennia marina, were studied throughout Sirik Azini creek (Iran) with a view to determine heavy metals bioavailability, and two methods were used. Results show that Zn and Ni had the highest concentrations in the sediments, while Cd and Cu were found to have the lowest concentrations in the sediments. Compared to the mean concentrations of heavy metals in sedimentary rock (shales), Zn and Cu showed lower concentration, possibly indicating that the origin of these heavy metals is natural. A geo-accumulation index (I _geo) was used to determine the degree of contamination in the sediments. I _geo values for Zn, Cu, Pb, and Ni showed that there is no pollution from these metals in the study area. As heavy metal concentrations in leaves were higher than the bioavailable fraction of metals in sediments, it follows that bioconcentration factors (leaf/bioavailable sediment) for some metals were higher than 1.     

Assessment of the Distribution,Sources and Potential Ecological Risk of Heavy Metals in the Dry Surface Sediment of Aibi Lake in Northwest China

The distribution, sources and potential ecological risk of heavy metals in the sediment of lakes in eastern China and other areas of the world that have undergone rapid economic development have been widely researched by scholars. However, this is not true for heavy metals in the sediment of rump lakes in the arid regions of China and world-wide. Because of this, we chose Aibi Lake to serve as a typical rump lake in an oasis in an arid area in northwest China for our study. Sediment samples were collected from the lake and then the quantities of the heavy metals Pb, Ni, Cd, Cu, Zn, Hg and Cr were measured. Then using a variety of statistical methods, we analyzed the distribution, sources, pollution status and the potential ecological risk of these metals. The results show that: (1) The amounts of the seven heavy metals all fell within the Second Soil National Standard, but the average and maximum values were all higher than the background values of Xinjiang in northwest China. (2) Multivariate statistical analysis determined that the Cd, Pb, Hg and Zn in the sediment were mainly derived from man-sources, and Cu, Ni, and Cr were mainly from the natural geological background. (3) Enrichment factor analysis and the geo-accumulation index evaluation method show that Cd, Hg and Pb in the surface sediment of the Aibi Lake were at low and partial pollution levels, while Zn, Cr, Ni and Cu were at no and low pollution levels. (4) Calculation of the potential ecological hazards index found that, among the seven tested heavy metals, Cd, Hg and Pb were the main potential ecological risk factors, and the contribution of each was 42.6%, 28.6%, and 24.0%, respectively. Cd is the main potential ecological risk factor, followed by Hg and Pb. This work revealed that recent economic development of the Aibi Lake Basin has negatively influenced the accumulation of heavy metals in the sediments of the lake, and, therefore, we should pay increasing attention to this problem and take effective measures to protect the ecology of the Aibi Lake Basin. This work can provide a scientific basis for an early warning of heavy metal pollution and for protection of the environment. Furthermore, it can serve as a reference when creating policies for the economic development in Aibi Lake Basin and environmental protection of rump lakes in arid regions of northwest China and other areas of the world.     

Distribution of Heavy Metals and Arsenic in Greenbelt Roadside Soils of Pudong New District in Shanghai

We studied the distribution of seven heavy metals and As in typical municipal greenbelt roadside soils in Pudong New District, Shanghai, China. As and Ni showed no significant accumulation compared with the background values of the local soils, but there was strong evidence of accumulation of Cd, Cr, Cu, Hg, Pb and Zn in the roadside soils. However, only Zn and Cd contents were higher than the pollution thresholds of the Chinese National Soil Quality standard. The concentrations of heavy metal(loid)s in the soils were significantly affected by the length of time since the roads were constructed. Soils from areas adjacent to an older road had higher levels of Cu, Pb, Cd and Zn. In terms of spatial distribution, more Cd, Cu, Pb and Zn were found in the soil from the green areas of median between carriageways than from those of the roadside verges. Vertical distribution analysis shows that the contents of Pb, Cd, Cu and Zn had maximum values in the topsoil and were substantially lower in the deeper layers of the soil profile. Moreover, correlation analysis reveals that these four heavy metals originated from the same pollution sources and their contents were directly associated with the traffic density.     

Metal (Fe, Zn, Cu, Pb and Cd) concentration patterns in components of a macrophyte-based coastal lagoon ecosystem

Information on the metal biological fate in macrophyte-based coastal lagoons is provided; this information can contribute to the assessment of the environmental effects of metal pollution and to the development of predictive models for rational management of coastal lagoons. Iron, Zn, Cu, Pb and Cd concentrations in the dominant invertebrate and fish species of Monolimni Lagoon, Mediterranean Sea, as well as in potential major sources for metal accumulation in these animals (water, sediments, angiosperms, seaweeds), were measured. Principal Component Analysis (PCA) was conducted using metal concentrations in invertebrates and fishes. All five metal concentrations loaded significantly on the first PCA axis; however, Zn and Cu loadings were less significant than Cd and even less than Fe and Pb ones. The samples of deposit-feeding invertebrates were separated from those of the rest of the organisms (browsing, herbivorous and carnivorous invertebrates, carnivorous gobies and muscle tissues of detritivorous mullets) along the first PCA axis. Deposit-feeding invertebrates displayed the highest Fe and Pb contents, and in general, the highest or comparatively high Cd, Zn and Cu ones. Carnivorous gobies showed comparatively high Zn contents and carnivorous shrimps the highest Cu ones, while muscle tissues of detritivorous mullets had low metal loads. In addition, there was no essential increase in metal concentrations corresponding to the increasing trophic level (autotrophs, to herbivores, to carnivores). Our findings suggest that (a) the variability in Fe, Pb and Cd contents in invertebrates and gobies depends at least to some extent on interspecific differences in feeding habits—deposit feeders accumulated the highest metal amounts probably due to high rates of uptake from sediments, (b) the variability in Zn and Cu concentrations in these organisms depends also on other interspecific differences apart from those in feeding habits, (c) metal accumulation in mullet muscle tissues does not depend markedly on feeding habits and (d) the trophic transfer of macrophyte-bound metals to the coastal lagoon food web is of relatively minor importance.     

浙江油茶产地土壤和果实金属元素含量特征

为探讨油茶(Camellia oleifera)产地土壤和油茶果实中金属元素分布和富集特征,在油茶果实成熟期,对浙江5个油茶产地土壤及油茶果实中金属元素进行污染分析和富集能力评价.结果表明,浙江油茶产地土壤中Pb、Cr、Cd、As、Hg、Ni、Cu和Zn含量低于农用地土壤污染风险筛选值,综合污染等级为安全.个别产区常山...     

包头南海子湿地三种鹭鸟羽毛与环境中重金属含量的关系

于2016年7至10月采用电感耦合等离子体发射光谱法(ICP-OES),测定了内蒙古包头南海子湿地繁殖期过后的白琵鹭(Platalea leucorodia)、苍鹭(Ardea cinerea)和夜鹭(Nycticorax nycticorax)3种鹭鸟初级飞羽及环境因子(水、土壤、食物)中As、Cd、Cr、Cu、Ni、Pb、Zn、Fe、Mn、Hg 10种重金属的含量,采用单因素方差分析方法比较了不同鹭鸟种类羽毛重金属含量差异,并通过生物富集系数及Pearson相关性检验分析了羽毛与环境因子间重金属含量之间的关系,以揭示包头南海子湿地环境中重金属污染现状及生物富集特征。结果表明:(1)被检测的10种重金属中,As、Cd、Cr、Cu、Pb、Zn、Hg 7种元素在湿地环境中均已超标,尤其土壤中Fe、Zn、Cu已达到重度污染的程度。(2)不同重金属元素在鹭鸟羽毛中的含量存在差异,其中Fe元素在白琵鹭羽毛中的含量水平最高(388.77 mg/kg),Cd元素在夜鹭羽毛中的含量最低(0.12 mg/kg)。在鹭鸟羽毛中重金属含量由高至低的顺序分别为,白琵鹭Fe、Zn、Mn、Cu、Hg、Cr、Ni、Pb、As、Cd,苍鹭Zn、Fe、Cu、Cr、Ni、As、Mn、Hg、Pb、Cd,夜鹭Zn、Fe、Mn、Cu、Ni、Pb、Hg、Cr、As、Cd。除Pb和Cd元素外,其他8种元素含量在3种鹭鸟羽毛中的含量种间差异显著。(3)相关分析表明,鹭鸟羽毛中的重金属含量与环境因子中的重金属含量显著相关且呈现富集特征,为此可作为监测当地环境污染的指示性材料。     

赣江上游沉积物重金属空间分布及污染特征

为了解赣江上游表层沉积物重金属污染特征,采集赣江上游38个样品,采用电感耦合等离子体质谱仪(ICP-MS,Agilent 8800)分析沉积物中重金属含量,结合内梅罗综合污染指数法、地累积指数法、主成分分析及沉积物质量基准等研究赣江上游沉积物中重金属污染程度,分析污染物可能的来源及评价其存在的生态风险。结果表明:赣江上游沉积物中W、Cr、Mn、Cu、Zn、As、Cd、Hg、Pb等9种重金属的平均含量分别为12.30、4.40、999.84、9.72、293.81、47.66、2.85、1.34、63.68 mg·kg-1;除Cr和Cu外,其余7种重金属的平均值均超过江西省土壤背景值。内梅罗综合污染评价表明,赣江上游表层沉积物中47.37%的采样点呈严重污染,28.95%采样点污染明显,其中污染程度章水段>桃江段>贡江段;地积累指数法显示,Mn、As、W、Pb呈轻度污染,Cd和Hg呈中度或偏重度污染;主成分分析显示,As、W、Hg、Pb具有相似的污染源,Cr和Mn具有相似的污染源;沉积物质量基准分析表明,对底栖生物可能产生毒性效应的重金属主要是Cd和Hg,主要分布在章水段和桃江段。     

Assessment of Heavy Metal Pollution in Water and Sediments from the Ghalechay River,Baychebagh Copper Mine Area,Iran

The concentrations of selected heavy metals in sediments and waters in Baychebagh copper mine were determined using ICP-OES. Except for Co, the average concentrations of Cd, Cu, Pb, and Zn in sediments from the Ghalechay River in the district exceed the world-average shale and continental upper crust value. Enrichment factors for Pb, Cu, and Cd were significantly enriched in sediments, indicating environmental contamination. Geoaccumulation index calculated for different sampling stations indicates that the sediments are unpolluted with respect to Co and Zn while unpolluted to moderately polluted with Cu and highly polluted with Pb and Cd. The Sediment Quality Guidelines (SQGs) suggest that Cd and Pb may pose the highest risk for the environment. Sequential extraction analyses of sediments revealed that Cu, Co, Pb, and Zn bound to extractable, carbonate, reducible and oxidizable fractions are lower than residual fraction. About 10% of the total Pb was associated with the exchangeable fraction, indicating remobilization, while Cd (89%), Pb (73%) Co (58%), Cu (76%), and Zn (68%) closely associated with the residual and oxidizable fractions, resulting in their environmental immobility. The residual forms are not expected to be released under normal conditions in the river and could be considered an inert phase.