Heavy metals in sediments and uptake by burrowing mayflies in western Lake Erie basin

During the past two decades, burrowing Hexagenia mayflies have returned to the western basin of Lake Erie. Because of their importance as a prey resource for higher trophic levels and their extensive residence time in potentially contaminated sediment, Hexagenia may be a source of heavy metal transfer. To better understand the distribution and transfer of heavy metals in sediment and mayflies, sediment and mayfly nymphs were collected from 24 locations across the western basin of Lake Erie in May 2007. Following USEPA protocols, samples were analyzed for 16 elements using ICP-OES or ICP-MS. Metal concentrations in the sediments exceeded the Threshold Effect Level for at least one metal at all sample sites. Sediment heavy metal distribution profiles indicate metal concentrations are correlated with organic matter content, and the highest heavy metal concentrations were found in the central deeper region of the western basin where organic content in the sediments was greatest. Hexagenia were distributed throughout the western basin, with greatest density (1350/m²) within the Detroit River plume. The Cd and Zn levels in mayflies were on average approximately 4 and 2 times greater, respectively, than sediment levels, and the Cd concentrations in the sediments exceeded the Threshold Effect Level at 27 of 28 sites and exceeded the Probable Effect Level at 9 of 28 sites. Spatial representation of heavy metal concentrations in mayflies exhibited a similar pattern to the spatial distribution of heavy metals and organic matter in the sediments with higher concentrations of metals found in mayflies residing in the central deeper region of the western basin.     

Role of bottom sediments in the secondary pollution of aquatic environments by heavy-metal compounds

The results of long‐term investigations into the concentrations of some heavy metals (Fe, Mn, Cu, Zn, Pb, Cr, and Cd) in the bottom sediments of the Dnieper reservoirs and the Dnieper–Bug estuary are considered. Maximum quantities of the metals studied are characteristic of southern water bodies located within industrial zones (the Zaporozh’e and Kakhovka reservoirs as well as the Dnieper–Bug estuary). The highest concentrations of the metals studied occurred in the clay silts (Fe, 11 600–32 400; Mn, 1504–3450; Cu, 38.9–85.5; Zn, 89.8–186.5; Cr, 48.6–193.0; and Cd, 1.9–4.4 mg kg^‐1 dry weight). Accumulation of heavy metals in the bottom sediments is an important factor in the self‐purification of aquatic environments. However, this process is reversible and therefore provides a constant threat of secondary water pollution. Secondary water pollution is observed in summer and autumn when water consumption increases. The concentrations of heavy metals increase by a factor of 1.5–3 after the drawdown of the water level. The main reason for the rise in the concentrations of metals is exchange between the bottom sediments and the water column. The rate of heavy metal migration is connected with the forms of occurrence in solid substrates and pore solutions in the bottom sediments, as well as with physico‐chemical conditions arising at the sediment/water boundary. Therefore, our investigations concentrated on the study of the fractional distribution of heavy metals among solid substrates and their forms of occurrence in interstitial solutions. This distribution depends, most of all, on the chemical properties of metals as well as the chemical and mineralogical composition of the sediments and the chemical properties of pore solutions. Most of the supply of Mn, Zn, Fe, and Cd is associated with oxides and hydroxides of iron and manganese (Mn, 74–93%; Zn, 43–70%; Fe, 27–59%; and Cd, 28–41%). Most copper and chromium is bound to organic matter and to scarcely soluble minerals. In the interstitial solutions studied, metals (except manganese) are found mainly as complex compounds with dissolved organic matter of a different molecular weight. Nevertheless, the fraction of complexes with a relatively low molecular weight (500–5000 Da) prevailed (40–70%). Dissolved manganese in the pore solutions consists chiefly of free (hydrated) ions Mn²⁺ (80–95%). The results obtained were used for a comparative evaluation of heavy metal mobility and the exchange ability of their associated compounds in the bottom sediment–water system.     

海河流域典型区域重金属沉积物生态风险研究

针对水库重金属污染及其生态效应问题，分析海河流域北部4座典型水库沉积物中6种重金属(As、Cr、Cu、Ni、Pb和Zn)的分布情况，并评价污染物类型的相关性。采用地累积指数法、潜在生态风险指数法和物种敏感性分布法分析4个水库沉积物中重金属的生态风险。结果表明：沙河水库、密云水库和于桥水库的重金属沉积物生态风险等级为优，官厅水库重金属沉积物生态风险等级为良。不同重金属对5%的底栖生物物种的危害质量分数(HC5)不同，由高到低依次为As(0.210 mg/kg)>Ni(0.071 mg/kg)>Cr(0.052 mg/kg)>Zn(0.050 mg/kg)>Cu(0.006 mg/kg)>Pb(0.005 mg/kg)。研究成果有助于了解水库沉积物中重金属的生态风险，为水库生态管理提供依据。     

河蚬扰动对不同质地沉积物中重金属生物有效性与毒性的影响

为探讨河蚬扰动对沉积物中重金属生物有效性与毒性的影响,制作重金属污染的不同质地沉积物(不同有机质含量和不同砂质含量)样品,采用室内模拟并借助间隙水平衡(Peeper)和薄膜扩散梯度(DGT)原位测定手段,试验研究了河蚬扰动作用下沉积物中重金属生物有效性以及毒性的变化特征。结果表明:河蚬扰动促进沉积物中重金属离子向上覆水释放,使上覆水中的Cd质量浓度增大了2%～12%,As增大了2%～198%;河蚬扰动使Cd、As的活性增大,在砂质沉积物中的活性大于有机质沉积物中的活性;河蚬扰动可促使沉积物中酸可挥发性硫化物的含量降低,进而改变其对沉积物中亲硫金属的结合能力,增强了沉积物中重金属的毒性。     

The impact of a sewage treatment plant's effluent on sediment quality in a small bay in Lake Geneva (Switzerland–France). Part 2: Temporal evolution of heavy metals

The Bay of Vidy is the most contaminated area of Lake Geneva, Switzerland, as a result of the release of treated and untreated waste water from the municipal sewage treatment plant of the city of Lausanne and its surroundings. The reconstruction of the historical deposition of heavy metals in the sediment of the bay has been performed by the analysis of several dated (radiocaesium) sediment cores. The presence of sewage‐derived contaminants in the Bay of Vidy since the beginning of the sewage treatment plant's operations in 1964 is clearly observed, when a sharp increase in heavy metal contents is recorded, with maximum concentrations of cadmium, copper, zinc and lead occurring between the late 1960s and early 1970s. Despite considerable improvement in recent times, the present concentrations of the investigated heavy metals in sediments of the Bay of Vidy are still higher than concentrations measured at the centre of the lake, the latter close to Lake Geneva's natural background values. It is concluded that the quantity of heavy metals deposited in the bay is considerable and, because of sediment instability, will constitute a potential hazard for biota.     

沙颍河表层沉积物中氮与重金属的分布特征及污染评价

为揭示沙颍河沉积物中氮及重金属的分布和污染特征,于2015年6—9月采集了沙颍河干支流主要站点的表层沉积物及上覆水样品,分析了其中氮的赋存形态和重金属的分布,探讨了水体-沉积物氮的转化机制及重金属的来源。结果表明:沙颍河表层沉积物中NO-3-N、NH+4-N、ON(有机氮)和TN的质量比分别为21.47~53.60 mg/kg、1.702 3~3.066 1 mg/kg、1 050~2 390 mg/kg和1 071~2 488 mg/kg,ON占TN的97.17%以上;表层沉积物中Cd、Cu、Zn和As质量比分别为1.583~3.533 mg/kg、21.98~64.60 mg/kg、148.5~165.5 mg/kg和1.527~2.416 mg/kg。Pearson相关性分析表明:表层沉积物中氮主要存在于有机物中,表层沉积物释放NH+4-N已经成为影响沙颍河水体NH+4-N浓度的一个重要因素;沙颍河大部分站点的表层沉积物有机指数和ON分别处于Ⅱ、Ⅳ级,有机碳污染较轻,ON污染严重;潜在生态评价中重金属Cd已经达到了很强-极强的污染程度,其余重金属则处于轻微污染水平;重金属潜在生态风险指数IR显示沙颍河表层沉积物重金属潜在风险已经到了很强-极强的水平,其中Cd对IR的贡献达97.22%。     

An investigation of rainwater tanks quality and sediment dynamics.

Rainwater tanks are being introduced into urban areas in Australia to supplement centralised potable supply systems. A pilot scale tank study and a full-scale field tank study found that heavy metal concentrations in water samples taken from the tank's supply point can, in some cases, exceed levels recommended by guidelines. Both studies also found very high concentrations of heavy metals in the sediments accumulated at the base of rainwater tanks. Laboratory experiments are underway to investigate sediment transport processes within a full-scale tank. Preliminary results demonstrate the effect of sediment resuspension on the quality of water released from the tank outlet. Improved tank designs that reduce sediment resuspension and mitigate impacts on water quality are the focus of future work.     

Nutrient and heavy metal storage and mobility within sediments in Kouris Reservoir,Cyprus

The objective of this study was to evaluate the risks associated with nutrient and heavy metal pollution in the water and sediments of Kouris Reservoir in Cyprus, and to recommend applicable measures to alleviate them. The reservoir drainage area contains various historic abandoned copper mines existing in an ophiolite geological substrate. Kouris Reservoir water is classified as oligotrophic to mesotrophic, with phosphorus being the limiting factor for algae growth. The thermal stratification of the reservoir enhances anoxic conditions in the reservoir hypolimnion, initiating phosphorus release back into the water column from the lake bottom sediments. The increased phosphorus release, in combination with increased water temperatures during the summer months (i.e. reaching 27 °C in August), may be the key factors enhancing the growth of microbial communities and cyanobacteria blooms. The sediment of Kouris Reservoir is classified as ‘low risk’ on the basis of the Ecological Risk Index scheme, in contrast to the Geoaccumulation Index, which indicates a moderate degree of contamination for chromium (Cr), nickel (Ni) and copper (Cu), and a high degree for lead (Pb). Heavy metals are strongly bound to the sediment matrix at pH values between 7 and 9, but can be released back into the water column at potential acid pH values. In addition, the sediments exhibit a high copper and chromium absorption affinity under current water quality conditions in the reservoir, as shown by batch absorption experiments. The experimental results suggest dredging of the reservoir sediment, and its subsequent dumping of the sediments near influent streams, would have adverse effects on the environment in the event of acid rain or other environmental changes that might acidify the sediment.     

Metals,acid-volatile sulfides,organics, and particle distributions of contaminated sediments

An overview of key physical/chemical parameters for contaminated sediments is presented. While sediment cores from remote lakes show little or no enrichment with heavy metals (Pb, Hg, Cd, Zn, Cu) and PAHs in top layers, the contamination near industrial areas is more significant. Cd in more bioavailable geochemical phases can occur in response to Cu inputs to sediments, and aeration during dredging operations of anaerobic sediments can reduce the pH causing release of heavy metals. The toxicity of anaerobic sediments to benthos can be effectively predicted based on interstitial water concentrations and the molar ratio between simultaneously extracted metals and acid-volatile sulfides (SEM/AVS). The toxicity of PAHs and other organics can be predicted based on equilibrium partitioning. Principal component analysis indicates that PAHs are associated with organic carbon and silt, and PCBs with inorganic clay. Finally, formulated reference sediments appear to be useful in toxicity testing by creating uniform parameters matching field conditions, and by isolating the effects of specific contaminants.     

The use of flux-corer experiments in the determination of heavy metal re-distribution in and of potential leaching from the sediments

Metal dynamics between sediments, interstitial water and overlying water are particularly complex. The movement of metals, their availability, and possible toxicity are influenced by various chemical and physical reactions and factors such as oxygen/redox gradients, pH, grain size, etc. To study the impact of oxygen on the release from and the re-distribution of Cd, Pb, Zn and Cu in sediments, flux-corer experiments have been optimised and performed.The flux experiment was carried out using 3 identical sediment cores. The first (control) sediment core was completely characterised before, the two other cores after the experiment. Pore water extractions and sequential extractions were performed on 2 cm depth intervals throughout the 20 cm long sediment cores.In the flux experiment, the sediment cores were exposed to a small volume of overlying water, which was continuously renewed. The change of trace metal mobility was assessed by following concentration-changes in the outflow. It has been found by the use of the flux-corer experiment, that the Cd, Pb, Zn and Cu concentrations in the outflow are at least 3–6 times higher during oxic conditions. Flux-corer experiments can be useful tools to facilitate the study of the change of heavy metal mobility and distribution in the sediment induced by the change in surface water policy.     

Two Dimensional Heavy Metal Transport Model for Natural Watercourses

This work presents the development and calibration of a two‐dimensional (depth‐averaged) river flow, sediment transport and heavy metal transport model in natural watercourses. Because heavy metals occur in dissolved and adsorbed phases, implementing the active‐layer concept for sediment transport computation enabled the development of a heavy metal transport model that accounts for pollutant moving in dissolved phase, adsorbed on suspended sediment, adsorbed on bed‐load, deposited in the active‐layer of the river bed or adsorbed on sediment in deeper strata. The proposed concept also enables the modelling of pollutant exchange processes using accessible sediment particle surface area for suspended and bed sediment separately. The presented heavy metal transport model is able to manage sediment mixtures found in natural watercourses using an arbitrary number of sediment size‐classes, distinguishing in this way smaller size‐classes that engage in interaction with the pollutant. Using field measurements for a reach of the Danube River, simulations were conducted for water flow, sediment transport and heavy metal transport. While some discrepancies between measured and computed values for pollutant concentrations were observed, the model reproduced the water and sediment contamination quite reasonably with acceptable mass conservation errors. The simulations also gave an insight in the general behaviour of the monitored heavy metals in the considered river reach. Therefore, it can be concluded that the developed model is suitable for simulating complex flow, sediment transport and heavy metal transport conditions in natural watercourses. Copyright © 2015 John Wiley & Sons, Ltd.     

Assessment of element distribution and heavy metal contamination in Chilika Lake sediments (India)

Chilika Lake is situated on the Indian east coast. It is one of the largest lagoons in the world, with a unique assemblage of marine, brackish water and freshwater species. Due to the opening of new connections to the sea in the years 2000 and 2008, an environmental change is expected in the lagoon. The study gives an assessment of sediment contamination by heavy metals on the verge of this change (sampling campaign in 2000). Sediment samples from two surface levels (0–5 and 30–35 cm), and from depth profiles, were analysed for mineralogical composition, main and trace element concentrations, and element bonding forms. Background concentrations from a depth profile were also examined. The profile spans a time of ≈13 500 years. Age determinations by radiocarbon dating and the ¹³⁷Cs- and ²¹⁰Pb-method were carried out. The composition of the surface sediments is generally uniform. The heavy metals exhibit slightly decreasing concentrations from NE to SW, thus indicating the supply of contaminants from the Mahanadi River. The anthropogenic portion of the heavy metal supply is mainly bound to Fe-oxide-hydroxides. Phosphorus is enriched in the sediments of the southern lake sector. Changes in element concentrations in the last 13 500 years have occurred mainly in two steps. The long-term variations exceed the anthropogenic changes caused by the Mahanadi River inputs. The very sensitive response of coastal area fabrics on climate changes also causes fast geogenic changes in element concentrations in sediments (similar grain sizes). This prevents the use of element concentrations from deep sediment horizons to define contaminations in those areas.     

Assessment of heavy metal contamination in coastal lake sediments associated with urbanization: Southern Kerala,India

The study of the spatiotemporal variation of heavy metals in lake sediments is of great importance because heavy metals can result in toxic effects on aquatic biota through bioaccumulation. This study was undertaken to evaluate the degree of heavy metal contamination in the lacustrine sediments and the corresponding environmental deterioration in a tropical, urban, coastal lake (Akkulam–Veli), located in Kerala, India. The spatiotemporal variations of the cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), manganese (Mn), nickel (Ni) and zinc (Zn) concentrations in the lake sediments, as well as various indices of anthropogenic contamination, including Contamination Factor (CF), Pollution Load Index and Geoaccumulation Index (Igeo), were used to assess the degree of contamination. This study indicated contamination of the lake sediments with Cu, Pb and Zn. Urban domestic sewage and land run‐off are the major drivers of the heavy metal loads to the lake. During the pre‐monsoon, sediment contamination occurs in the upstream portion of Akkulam Lake because of a high clay content in the sediments. During the monsoon period, Akkulam Lake and the upstream portion of Veli Lake exhibit sediment contamination owing to high silt content. Domestic sewage is the main source of copper and zinc to the lake. Sewage bypass into the drains in the lake basin is largely responsible for the copper and zinc sediment contamination. High traffic levels and wastewater discharges from service stations/workshops are the main cause of the Pb loads entering the lake. Rubber particles of vehicle tires contain zinc and copper pigments that can accumulate on the surface of busy streets, entering the drains during rainfall events. Based on these study results, the accumulation of copper, zinc and lead in lake sediment can be controlled to a great extent by restricting the above‐noted activities. As the sediment content of lead, zinc and copper is confined to the clay fraction during the non‐rainy season and to the silt fraction during other seasons, lake restoration work should largely incorporate treating the clay and silt fractions, respectively, during both the non‐rainy season and rainy season.     

阳宗海表层沉积物中的重金属生态风险评估

对从阳宗海湖底表层采集的25组沉积物样品中的10种重金属质量比进行分析,结果表明,Ti、Mn、Zn、V、Cr、Cu、Ni、Co、Pb和As的质量比平均值均超过了当地土壤背景值。而重金属系统聚类分析表明,Zn、Cr、Pb、As高度相关,其污染主要由于人类活动造成;Ti、Mn、V、Cu、Ni、Co的分布特征相似,其污染原因以岩石风化等自然因素为主。单因子富集系数评价表明,阳宗海10种重金属均达到了中度富集程度,其中As、Cu、Cr富集程度较为突出。用Hakanson潜在生态风险指数法评价阳宗海表层沉积物中重金属的生态风险,结果表明,阳宗海表层沉积物中重金属的生态风险总体属轻微程度,阳宗海南岸局部区域达到中等生态风险程度。几种重金属对阳宗海生态风险的贡献由大到小依次为As、Cu、Co、Ni、Pb、Cr、V、Zn、Mn、Ti,其中,As是阳宗海最突出的生态风险因子。     

An assessment of sediment reuse for sediment management of Gallito Ciego Reservoir,Peru

Gallito Ciego Reservoir, with a surface area of 14.2 km² and mean depth of 40.3 m, is located in the Jequetepeque River basin in north‐western Peru. It is rapidly filling with sediments, endangering its main purpose of supplying agricultural irrigation water. A sediment volume corresponding to 70% of the dead water volume has accumulated in the reservoir up to 2007, with reservoir bottom outlet becoming blocked. Below the dam, 35 000 ha of irrigated cropland, supporting 115 000 habitants, are endangered. This study was conducted to evaluate the possibilities of sediment management, especially the use of the sediment for agricultural purposes in the Jequetepeque River basin. Sediment samples were collected from littoral and profound sites in the reservoir. Suspended sediments also were collected. Physical parameters were investigated, and the nutrient and heavy metal concentrations were determined. By comparing grain‐size distribution and nutrient content, as well as pollutant concentration of the sediments, to those of terrestrial soils near the reservoir, an assessment of the potential for applying the sediments on the cropland was undertaken. Texture investigations of profound sediments revealed a strong grain‐size classification within the reservoir. Because the heavy metal concentrations in the sediments were below toxic thresholds, and the concentrations of nutrients also were low, using the sediments for agricultural purposes would not constitute risks, although they cannot replace fertilizer. As a soil amendment and building material, the sediments do have an economical value. Its dredging and use, however, must be seen as only one component of more holistic sediment management of the Jequetepeque Watershed.     

Sediment and heavy metal distribution and transport in a coastal area affected by a submarine outfall in the Basque Country (Northern Spain)

In 1989 a submarine outfall was brought into service in the coastal area of Zarautz, in the Basque Country (north of Spain). The outfall discharge point is located at −35 m depth and −1 km offshore. This work deals with the sediment dispersion and distribution patterns in the vicinity of an outfall. The methodological field procedures included bathimetric surveys and sediment sampling for grain size characterization and analysis of organic matter content and heavy metal concentrations. Sediment resuspension and transport paths were estimated. Small-sized sediments have been only deposited in the proximity of the outfall discharge point. Heavy metal distribution in the sediments shows only minor influence of the outfall. Only under storm weather conditions sediments will get into suspension. Sediment transport studies suggest a net transport from the outfall discharge point to the N-NW. It can be established that sediments discharged by the outfall will not be transported coastwards; thus, water quality in this area will not be affected.     

Sedimentology and Geochemistry of Modern Sediments in the Kingston Basin of Lake Ontario

Accumulation of Recent fine sediment is limited to deep water areas in the Kingston basin and thicknesses of more than 50 cm are found only in the St. Lawrence trough; elsewhere, sands and silty sands are largely composed of reworked material. Local sources provide little input of fine sediment to the Kingston basin. Statistical relationships derived from geochemical analyses indicate several forms of association between heavy metals and organic carbon, sulphides, clays, hydrous Fe and Mn oxides, and carbonates. A comparison between Kingston and Niagara sediments shows that the combined effects of riverine and lacustrine erosion have resulted in a generally greater content of carbonates in the Niagara sediments. The content of Fe (which is partly influenced by redox potential) is highest, however, in sediment of the Kingston basin, where higher P values are also associated with an increased clay content. Differences in the concentrations of heavy metals in Lake Ontario, except for Hg, Co, Cu, and Zn, are largely explained by variations in silt and clay contents. Contaminant loadings from the Niagara River are largely responsible for the anomalously high concentrations of Hg and, to a lesser extent, Cu and Zn. Cobalt occurs at higher concentrations in the sediments of eastern Lake Ontario, where its presence is thought to reflect glacial dispersal patterns.     

Environmental risk assessment of surface water and sediments in Copenhagen harbour

The environmental risk assessment of Holmen, a former naval base, included characterisation of the sediments with regard to pollution with xenobiotics, heavy metals, nutrients and bacteria, and ecotoxicity. A simple hydraulic model was established, and the release of substances from the sediment to the water was assessed. Sediment biotests with Corophium volutator and porewater biotests with Skeletonema costatum and Acartia tonsa were conducted. The sediment was characterised as strongly contaminated in the major parts of the investigated area. Based on the application of the acid volatile sulfide method it was concluded that practically none of the heavy metals were bioavailable. Both the sediment and the porewater from a number of stations were toxic. The toxicity did not appear to be attributable to the content of heavy metals, more likely to other contaminants. Furthermore, the sediment, which has served as a sink for accumulation of contaminants over a period of many years, also may constitute a source of contamination due to potential release of heavy metals and xenobiotics from the sediment to the water in some areas. The release appears to give rise to concentrations above the EU Water Quality Objectives at some stations.     

Redox-related release of phosphorus from sediments in large and shallow Lake Peipsi: Evidence from sediment studies and long-term monitoring data

In large and shallow lakes, the role of the redox-related release of phosphorus (P) from sediments has remained in the shadow of sediment resuspension. In the current study, we concentrated on this knowledge gap regarding factors controlling lake water quality. We combined long-term monitoring data with the studies on sediment P mobility in August 2018 by measuring redox potential, pore water concentrations of soluble reactive phosphorus (SRP), dissolved iron (Fe), sediment P fractions, and by calculating diffusive P flux. Using lake water total P (TP) concentrations for 21 years (1997–2018), we quantified internal P load based on water column summer increase of TP (IL_{in situ}). Significant positive correlations were found between the diffusive P flux and the Fe-bound P concentration in the sediment for conditions of well-oxidized sediment surfaces. The analysis of long-term data showed that P mobilized in sediments is likely to be released via sediment disturbances. Sediment resuspension is favoured by decreased water level during late summer-early autumn. Additionally, the release of P from anoxic sediment surfaces is also possible, as was indicated by significant positive correlations of IL_{in situ} with the anoxic factor (a measure of extent of anoxia) and August water temperature. The potential P release from anoxic sediment surfaces contributed about 80% to IL_{in situ} in the northern basin, and about 280% in the more productive southern basin. Hence, the redox-related P release seems to sustain the high productivity of these large and shallow lake basins and is supported by sediment resuspension as a transport mechanism.     

Fractionation of heavy metals in sediment cores from the Ell-Ren River,Taiwan

Fractionation of heavy metals (Cr, Cu, Co, Zn, Ni, and Pb) in sediment cores taken from three heavily polluted locations of the Ell-Ren River in southern Taiwan was studied. After the three sediment cores were separated into several depth sections, sequential extraction procedure was used to determine the variations in heavy metal binding fractions (exchangeable, bound to carbonates, bound to Mn oxides, bound to Fe oxides, and bound to organic matter) with different sediment depth, and followed by multivariate analyses. It turns out that a deeper sediment depth tended to result in smaller amounts of total extractable heavy metals (TEHMs), indicating that heavy metal pollution of the river has been intensifying these years. The decreasing order of TEHMs was: Zn > Cu > Pb > Cr > Ni > Co. The TEHMs Zn and Cu detected from different depth of the three sediment cores were mainly originated from “bound to carbonates” and “bound to organic matter” fractions, respectively. Also, the percentages of the heavy metals contained in each of the five binding fractons only slightly varied with sediment depth. From multivariate analyses, all the heavy metals except Co behaved similarly and might be discharged from the same pollution sources.