Distribution and Chemical Forms of Heavy Metals in the Flood 1997 Sediments of the Upper and Middle Odra River and its Tributarie:, Poland

At the beginning of August 1997, 72 samples of flood sediments were taken along the Upper and Middle Odra river and its tributaries. The concentrations of Zn, Pb, Cu, Cd, Co, Ni, Cr, Mn, and Fe in the bulk samples and in the <20 μm fraction were determined by AAS method. The contents of metals vary in wide ranges and are significantly higher in the <20 μm fraction of sediments. The range concentrations vary as following: Zn 274...3 656 mg/kg, Pb 79...1 773 mg/kg, Cd 1.7...11.8 mg/kg, Cu 38...2 244 mg/kg, Cr 14...384 mg/kg, Co 4...73 mg/kg, Hg 0.2...3.9 mg/kg, Mn 214...6 972 mg/kg, and Fe 1.5...16.3 %. The highest amount of the metals was found in the Wrocław and Głogów regions. The mobile (exchangeable and carbonatic fractions) portions of metals reached up to 50 % of Zn, 40 % of Pb and Cu and 60 % of Mn.     

Spatial distribution and bonding forms of heavy metals in sediments along the middle course of the River Elbe (km 287ċ390)

Sediments of eight groyne fields along the middle course of the River Elbe (river km 287?390) were geochemically studied. The 78 sediment samples were analysed for pH and grain size distribution. The grain size fraction < 2 μm was used for mineralogical and chemical analysis: semiquantitative clay mineral analysis; total element content (Al, Ca, Fe, K, Mn, Cd, Cr, Cu, Ni, Pb, Zn), total inorganic and organic C, and bonding form fractionation with a six‐step sequential chemical extraction. The latter was performed on selected samples (n = 32). The sediments along the Elbe's course are still contaminated with heavy metals far above the local geogenic background level. An enrichment factor of more than 15 was calculated for zinc. Cr and Ni are the elements with the lowest enrichment. The bonding form analysis of selected heavy metals shows a dominance of relatively immobile bonding forms, e. g. the moderately reducible and the residual fraction, which implies a relative low mobility potential. Only Zn poses a higher potential threat to the environment, since it has a higher percentage of the first three extracted phases: adsorbed, carbonate, and easily reducible fraction.     

The distribution of trace metals in Florida Bay sediments

The distribution of trace metals based on surface sediments collected at 40 stations across Florida Bay was done in June, November and February 2000-2001. Concentrations of Sc, V, Ba, Cd, Cr, Co, Cu, Pb, Mn, Ni, Zn, Al and Mg were determined by ICP-MS, and the total Fe was determined by spectrophotometry. Organic carbon (OC), nitrogen (N), and calcium carbonate (CaCO3) were also measured. Eleven of 13 metals showed a similar distribution pattern for the various months studied. Maximum concentrations of metals were lower than those found in most estuarine systems and were concentrated in the north-central and western zones of the Bay. The Mn and Fe concentrations, unlike the other metals, gradually decreased from north (Everglades) to south (Florida Keys). Some metals (Ni, Zn, Cu, Cr, Pb and Ba) associated with petroleum use showed high concentrations at stations near the Tavernier marina. Florida Bay sediments are predominately CaCO3 (65.9-92.5%). The greatest value for OC (5.5%) and the lowest value of CaCO3 (65.9%) were found in the western zone. Trace metal distribution patterns are similar to the OC and N in the sediments. There was a strong correlation between most metals (V>Cu>Ni>Cr>Al>Co>Ba>Zn>Pb>Mg) and the percentage of OC. The maximum C/N values (9-12) were observed at the stations with the highest OC, where dense colonies of seagrass are found and most of the metals are concentrated. All metals except Mg, Mn and Co showed a strong correlation with Al and the fine fraction of the sediments (aluminosilicates) associated with continental input and river runoff.     

Study on the Historical Distribution of Metals in Aquatic Sediments

In this study, the historical distribution of metals, phosphorous, and sulfur at four different depths in the sediments of different lakes formed in the course of an urban river (in Londrina, Parana State, Brazil) were determined. The transport of metals along the course of the river was observed mainly for Mn, Cr, and Zn. High concentrations of Pb in the Capivara Bay and Cr in the river were attributed to contamination from a battery plant and a tannery, respectively. The concentrations of heavy metals in the deepest layers of the sediments remain high several years after deposition.     

Concentration of 7 Heavy Metals in Sediments and Mangrove Root Samples from Mai Po, Hong Kong

Concentration of 7 heavy metals, Zn, Fe, Cu, Cr, Cd, Pb and Ni in mudflat sediments, mangrove root sediments and root tissues of Acanthus ilicifolius, Aegicerus corniculatum and Kandelia candel from the Mai Po Nature Reserve, Northwest Hong Kong, were measured. Metal concentrations in the upper 0–10 cm of the sediment cores from the mudflat were 4–25% higher than those found in the bottom 21–30 cm. Relative Topsoil Enrichment Index approximated 1.0 for all the metals. Mudflat sediment concentrations of Fe, Ni, Cr, Cd and Cu were greater than those found in the mangrove sediments. Except for Fe, concentrations of the other 6 heavy metals were more elevated in the mangrove root sediments than in the corresponding root samples. Higher concentration factors for Zn, Fe and Cu may indicate bioaccumulation. Mean metal concentrations in both mudflat and mangrove sediments decreased in the order Fe > Zn > Pb > Ni > Cu > Cr > Cd. Mangrove root tissues also showed the same pattern except that Pb > Cu > Ni     

The distribution and speciation of trace metals in surface sediments from the Pearl River Estuary and the Daya Bay, Southern China

Surface sediments collected from the Pearl River Estuary (PRE) and the Daya Bay (DYB) were analyzed for total metal concentrations and chemical phase partitioning. The total concentrations of Cr, Cu, Ni, Pb, and Zn in the PRE were obviously higher than those in DYB. The maximum concentrations of trace metals in DYB occurred in the four sub-basins, especially in Dapeng Cove, while the concentrations of these metals in the western side of the PRE were higher than those in the east side. Such distribution pattern was primarily due to the different hydraulic conditions and inputs of anthropogenic trace metals. The chemical partitioning of metals analyzed by the BCR sequential extraction method showed that Cr, Ni, and Zn of both areas were present dominantly in the residual fraction, while Pb was found mostly in the non-residual fractions. The partitioning of Cu showed a significant difference between the two areas.     

太湖流域滆湖底泥重金属赋存特征及其生物有效性

为了探讨太湖流域滆湖底泥重金属(Cd、Cr、Cu、Zn、Ni和Pb)的赋存特征及其生物有效性,对底泥重金属总量、形态以及生物富集量进行了分析.结果表明,6种重金属含量的空间分布表现为北部湖区最高,其次为南部湖区,中部湖区最低,重金属Ni、Cu、Zn和Pb含量显著高于沉积物背景值,分别是背景值的4.77、3.89、2.96和2.76倍,重金属总量与沉积物中的黏土成分含量具有显著相关性.采用三级四部提取法对重金属形态进行分析表明,6种重金属的生物有效态(弱酸结合态、可还原态和可氧化态之和)含量顺序为CdCuZnPbNiCr,其中Cd、Cu、Zn和Pb的生物有效态含量分别占总量的84.15%、78.47%、76.50%和64.29%.Cu和Zn在铜锈环棱螺中富集含量要显著高于其他金属元素.相关性分析表明,6种重金属中仅Cr和Pb的生物富集量与有效态含量具有显著相关性,这表明,重金属在生物体内的富集不仅与有效态含量有关,还与底泥重金属总量有关.因此,评价滆湖重金属的生态风险时需要综合考虑重金属的总量及生物有效态含量.     

Assessment of Metal Pollution in Water and Surface Sediments of the Seyhan River,Turkey, Using Different Indexes

The aim of this study was to assess the level of heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) contamination and enrichment in the surface sediments of the Seyhan River, which is the receiving water body of both treated and untreated municipal and industrial effluents as well as agricultural drainage waters generated within Adana, Turkey. Sediment and water samples were taken from six previously determined stations covering the downstream of the Seyhan dam during both wet and dry seasons and the samples were then analyzed for the heavy metals of concern. When both dry and wet seasons were considered, metal concentrations varied significantly within a broad range with Al, 7210–33 967 mg kg^?1 dw; Cr, 46–122 mg kg^?1 dw; Cu, 6–57 mg kg^?1 dw; Fe, 10 294–26 556 mg kg^?1 dw; Mn, 144–638 mg kg^?1 dw; Ni, 82–215 mg kg^?1 dw; Pb, 11–75 mg kg^?1 dw; Zn, 34–146 mg kg^?1 dw in the sediments while Cd was at non‐detectable levels for all stations. For both seasons combined, the enrichment factor (EF) and the geo‐accumulation index (I_geo) for the sediments in terms of the specified metals ranged from 0.56 to 10.36 and ?2.92 to 1.56, respectively, throughout the lower Seyhan River. The sediment quality guidelines (SQG) of US‐EPA suggested the sediments of the Seyhan River demonstrated “unpolluted to moderate pollution” of Cu, Pb, and Zn, “moderate to very strong pollution” of Cr and Ni. The water quality data, on the other hand, indicated very low levels of these metals suggesting that the metal content in the surface sediments were most probably originating from fine sediments transported along the river route instead of water/wastewater discharges with high metal content.     

Influence of mangrove reforestation on heavy metal accumulation and speciation in intertidal sediments

To investigate the influence of mangrove reforestation on heavy metal accumulation and speciation in intertidal sediments, core sediments from a restored mangrove forest and adjacent mud flat in Yifeng Estuary (southeastern China) were analyzed. The chemical speciation of heavy metals (Pb, Zn, Cu, Cr and Ni) was determined according to a sequential extraction procedure. Special attention was paid to the upper 20 cm of sediment, in which metal accumulation was enhanced and speciation was obviously modified. Mangrove reforestation decreased the concentrations of all metals in the acid-soluble fraction and increased metal concentrations in the oxidizable fraction. Increased Pb, Zn and Cu concentrations and decreased Ni and Cr concentrations were observed in the reducible fraction. These results suggest that mangrove reforestation facilitated the accumulation of heavy metals in the upper sediment layers but decreased their bioavailability and mobility.     

Metals in Sediments of the Upper Laguna Madre

The Laguna Madre system is the largest hypersaline coastal basin in the United States. Surface sediments from 22 Upper Laguna Madre (ULM) sites were analyzed for grain size and metals (Cd, Cu, Ba, Cr, Mn, Ni, Pb, V, Zn, Fe, and Al) to assess the extent of contamination in the area. Sediments were found to consist mainly of sand texture. Clay and silts were minor constituents (<10%) of the sediments. Anomalies in metal concentrations were found at some sites and were related to probable sources, i.e., recreational and industrial activities. Concentrations of metals were normalized to grain size, Al, and Fe to distinguish natural and anthropogenic sources. Most metals showed positive correlations (p < 0.001) with Fe and Al, suggesting a natural variability of metal concentrations in sediments. Concentrations of metals, except Cd and Pb, at most sites were found to be below threshold concentrations thought to produce toxic effects in marine and estuarine organisms.     

Chemical forms of heavy metal contaminants in sediments of Miyun reservoir

The chemical forms, spatial distribution and sources of As, Hg, Cd, Pb and Zn in sediments of the Miyun reservoir were studied. The results of sequential extraction demonstrate that most of As, Pb and Zn were bound to the residual fraction, Hg was associated with the sulfide fraction while Cd was associated with the carbonate fraction and the residual fraction. On the vertical profiles the concentrations of the heavy metals in total and each fractions mostly decreased with increasing depths in sediments, suggesting that the heavy metals input from the upstream watershed increases yearly. Summation of the residual fraction, the sulfide fraction and the carbonate fraction accounts for 60.03%―85.60% of the total heavy metal contents in the sediments, which represent the geochemical background values of the elements and relate closely to soil erosion. Results of the main factor analysis show that most sediments of the reservoir come from the upstream soil erosion, the point source pollution and domestic waste. Moreover, the microbial activities taking place on the sediment-water interface are also one of the major factors to cause the increasing content of the organic matter fraction and the iron-manganese oxide fraction. Environmental change of the reservoir water could make the removability of the heavy metals increase, leading to the increase of their concentrations in pore water in sediments, and imperiling water quality of the reservoir.     

Evaluation of geochemical behavior and heavy metal distribution of sediments：The case study of the Tirumalairajan river estuary,southeast coast of India

The purpose of this study was to assess the chemical partitioning of selected heavy metals(Fe,Mn,Cu,Zn,Pb,Cr,Co and Ni) in 10 surface sediments at Tirumalairajan River Estuary in the southeastern coast of India.A five-step sequential extraction technique was used to assess the environmental status of heavy metals.Most of metals were considered to be immobile due to the high availability in the residual fraction of heavy metals.The sediments of Tirumalairajan River estuary had not been polluted by heavy metals,and they didn’t pose any high ecological risk.The seasonal variations of heavy metals were slightly higher in summer than in monsoon season.Factor analysis was also carned out to understand the associations of metals in different fractions with sand,silt,clay,organic matter,pH,salinity and other metals.The relationship between the Q-mode and R-mode cluster analyses was useful for identifying the pollution levels in both seasons.It was proved that the enrichment of heavy metals was related with geogenic and anthropogenic sources.The information on total metal concentrations in sediments was not sufficient for assessing the metal behavior in the environment,but the sequential extraction technique was more effective in estimating the environmental impact of contaminated sediments.     

Geochemical baselines of major, minor and trace elements in the tropical sediments of the Terengganu River basin, Malaysia

The geochemical baselines and distribution of 31 elements (Al, Fe, K, Na, Mg, Ca, Mn, Ba, Cr, Zr, Ni, Sr, Zn, Y, Li, Cu, Mo, Nb, Th, Co, Ga, W, Ta, Be, Ti, Ge, Se, Bi, Te, Sc and Re) and physico-chemical parameters of the tropical surface sediments of the Terengganu River basin, Malaysia, are reported. Sediments are sandy loam to sand in texture consisting of mostly quartz, low organic matter content (average-2.68%), low CEC (average-2.02 cmol(+)/kg) and mildly acidic pH1:5 (average-5.91). Concentrations of Mn, Fe, Ba, Cr, Ni, Cu, Mo and Se were measured to be above the environmental sediment quality criteria at various locations. Lake sediments registered significantly higher Al, Fe, Ti, Mg, Ca, Mn, Te and Sc concentrations as compared to the river sediments. Most of the elements investigated showed an association with silt size fraction (2-63 μm). Among the investigated metals, Mo and Fe concentrations showed an increasing (5-fold) and decreasing (3-fold) trend, respectively, along the river path from the upstream to the downstream depending on the stream pH-redox conditions. The enrichment factor values (EF 5) of Cr, Ni, Mo and Se indicated enrichment from anthropogenic activities. Alkali and alkali earth metals registered a significant depletion (EF values 0.7) as compared to the Earth's crust. Principal component analysis of the two main components (PC1, 87.4% and PC2, 8.7%) revealed a well-defined group of estuary sediments. Lake and river sediment sampling locations did not form defined groups revealing heterogeneity in the origin of geologic material and the in-stream geochemical processes. However, Cr, Ni, Mo and Se formed a separate group with elevated concentrations (e.g. Cr1,000 mg/kg) indicating contamination of sediments. This work presents the geochemical baselines of the tropical sediments as industrial development and urbanization along the north east coast of Peninsular Malaysia are advancing rapidly.     

Chemical forms of Pb, Zn and Cu in the sediment profiles of the Pearl River Estuary

The chemical forms of heavy metals (Pb, Zn and Cu) in sediment cores of the Pearl River Estuary were studied using a sequential chemical extraction method. The isotope ratios of 206Pb/207Pb in various chemical fractions were also measured to assess the potential Pb sources. Zinc and Cu were mainly associated with the residual fraction. The Fe-Mn oxide and organic/sulphide fractions were the next important phases for Zn and Cu, respectively. For Pb, different chemical partitioning patterns were found among different sediment cores. Most Pb was associated with the residual fraction in the sediments. In some sediment profiles, the major phase of Pb in the top layers was the Fe-Mn oxide fraction. The proportion of Pb in the Fe-Mn oxide fraction decreased significantly with increasing depth. Among the different depths, the 206Pb/207Pb isotope ratios in the residual fraction remained fairly stable, with a mean value of 1.202, which may represent the natural background value. The 206Pb/207Pb ratios in the exchangeable fraction were the lowest among the five fractions, particularly in top sediments, showing the anthropogenic inputs of heavy metals from recent rapid industrial development in the surrounding region. For the other three non-residual fractions, there was a similar trend of increasing 206Pb/207Pb ratios down the profile. Results from this study are useful in assessing both the chemical changes for heavy metals in marine sediments and the potential of heavy metal release into the water environment of an estuary area.     

Spatial distribution,fractionation and ecological risk assessment of potentially toxic metals in bottom sediments of the Zarivar freshwater Lake (Northwestern Iran)

Freshwater lakes are one of the most vulnerable ecosystems to environmental contamination. This study was initiated to assess the spatial distribution, fractionation, ecological risk of selected potentially toxic metals (Pb, Zn, Cu, Cr, and Ni) in bottom sediments of the Zarivar lake, the second largest freshwater lake in Iran. The results revealed that Pb, Zn and Cu had the high spatial variability (coefficient of variation >50) across the sampling sites and their maximum concentrations (197.5 for Pb, 198.7 for Zn and 185.6 mg/kg for Cu) were observed in sampling sites from the northern, western and eastern margins of the lake. Cr and Ni with average concentrations of 28.3 and 31.38 mg/kg respectively, exhibited low spatial variability (coefficient of variation <20) and their concentrations did not vary significantly among the sampling sites. Based on the redundancy analysis (RDA), sediment organic matter was strongly correlated with Pb, Zn and Cu while Fe₂O₃ and Al₂O₃ showed a positive correlation with Ni and Cr. The calculated average enrichment factor (EF) and geoaccumulation index (I_geo) showed that the contamination level of metals can be arranged in the following order of Pb> Cu > Zn > Cr > Ni. Results from the modified five-step sequential extraction analysis indicated that 40 % of total Pb and Zn were associated with the reducible fraction, 45 % of Cu with the oxidizable fraction and more than 80 % of total Ni and Cr were retrieved from the residual fraction. It was also noticed that Pb, Zn and Cu were more incorporated into the non-residual fractions in the sites with a higher total concentration of these metals, suggesting that both total concentration and fractionation behavior of metals were influenced by their potential sources in the study area. Ecological risk assessment using the potential ecological risk index (PERI) and the modified potential ecological risk index (MPERI) showed that sediments from the eight sampling sites pose a moderate to considerable risk whereas the other sites had low ecological risk level. In comparison to sediment quality guidelines (SQGs), the effects range low (ERL) and probable effect level (PEL) values for Pb, Cu and Zn were exceeded at some sampling sites while Ni and Cr concentrations were found to be below or close to their SQGs values at all the sampling sites. Pb was generally identified as the contaminant of most concern in the study area. Taking into account the results obtained from the fractionation study and the source contribution estimate, it can be inferred that the Pb, Zn and Cu with the average contribution of 79, 54 and 64 % respectively, were mainly derived from anthropogenic sources whereas Ni and Cr with the estimated contribution of 80 and 89 % were predominately from the lithogenic source.     

Present state and historical changes of trace metal pollution in Kaoping coastal sediments, southwestern Taiwan

Surface and gravity-cored sediments were collected from the Kaoping coastal area off southwestern Taiwan to determine particle size, organic carbon, trace metal concentration and enrichment factor (EF), 210Pb dating, and 206Pb/207Pb ratio for determining present and historical metal pollution. Surface distributions of trace metals ranged from 0.02 to 0.13 mg/kg for Cd (EF: 0.16-1.65), from 35 to 189 mg/kg for Cr (EF: 0.85-2.92), from 25 to 64 mg/kg for Ni (EF: 0.53-2.38), from 10 to 32 mg/kg for Pb (EF: 1.20-4.94), and from 29 to 129 mg/kg for Zn (EF: 1.18-3.50). Trace metal concentrations correlate closely with distributions of mud (<63 microm) and organic carbon which accumulate largely around river mouths and within the Kaoping Canyon. With the exception of Cd, Cr and Ni in certain areas with rather coarse sediments, metals were generally elevated above the baseline levels over the studied area. Metals were also relatively enriched in areas with high contents of mud and organic carbon. Sedimentation rates derived from the excess 210Pb data in core sediments sampled from the canyon illustrate metal pollution beginning around 1970 that is corresponding to the booming time of economic growth in Taiwan. Meanwhile, the status of Pb pollution in core sediments is verified by an inversed correlation between 206Pb/207Pb ratios and Pb concentrations. Anthropogenic Pb and other metals in the studied area were apparently derived primarily from the Kaoping River and accumulated around the river mouth and within the Kaoping Canyon. The Kaoping Canyon appears to act as a major sink for river borne trace metals.     

南京玄武湖底泥重金属形态与环境意义

通过对玄武湖12个底泥样品采用连续提取的方法,分别获得湖中6种金属的总量和形态分布数据,并用因子分析的方法对金属总量进行统计分析.金属总量结果表明,部分样点的Ni和大部分样点的Cr、Pb、Zn超过背景值,显示有轻度污染,这与玄武湖周围的地理环境和人类活动对底泥重金属的影响有关.对金属形态分析的结果表明,在所测金属中残渣态是主要的存在形式,其次比例较高的是有机物和硫化物结合态,而Pb、Zn有潜在的生物危害性.     

Evolution of Heterogeneous Mixed Siliciclastic/Carbonate Aquifers Containing Metastable Sediments

Mixed carbonate and siliciclastic marine sediments commonly become freshwater aquifers in eastern coastal regions of the United States and many other global locations. As these deposits age, the carbonate fraction of the sediment is commonly removed by dissolution and the aquifer can become a solely siliciclastic system or contain zones or beds of pure quartz sand. During aquifer evolution, the sediment grain size characteristics, hydraulic conductivity, and porosity change. An investigation of these changes using mixed carbonate/siliciclastic sediment samples collected from a modern barrier island beach in southern Florida showed that the average mean grain diameter decreased with removal of the carbonate fraction, but the average hydraulic conductivity and porosity increased slightly, but not to statistical significance. This counterintuitive result occurs because of the change in the pore types from a combined shelter and intergranular pore system producing a dual porosity system in the mixed sediments to a single intergranular pore system in the siliciclastic sediment fraction. Within the mixed carbonate/siliciclastic sediment, in the pure carbonate fraction, large shell fractions form grain‐supported large pores, which become filled with sand‐sized quartz as the shell fragments decrease in size or as the sediment becomes compacted. The hydraulic conductivity increases because the shell fragments that were oriented perpendicular to flow caused an increase in the length of the flow path, or a larger scale tortuosity, compared with the flow through pure quartz sand.     

Size Fractions of Heavy Metals in Waters

The heavy metal content of river water samples with 12 and 15 mg/l dry matter of seston is increased to 400 … 3900μg/l by the addition of inorganic heavy metal salts, and after three days the distribution of the heavy metals is determined by fractional filtration (8, 3, 1.2, 0.8, 0.65, 0.45 and 0.22 μm pore size). More than 80% of Ni, Co and Mn are found in the fraction <0.22 μm, 60% of Pb and Cu in >8 μm as well as 40 and 25%, resp., in <0.22 μm, Cd, Cr and Zn are found in all fractions, 60 … 80% being in the fraction <0.22 μm, 90% of Fe occurring in the fraction >8 μm. The influence of specific parameters of water quality as pH-value and seston concentration on the distribution requires further investigations.     

巢湖沉积物重金属富集特征与人为污染评价

本文分析了巢湖主要入湖河流河口区表层沉积物及西部湖心区沉积岩芯中Al、Fe、Ni、Cr、Cu、Zn、Pb、Li、V等金属元素变化特征,采用地球化学方法对金属元素变化的"粒度效应"进行矫正,并以Li、V为参照元素对矫正结果进行检验;参考历史沉积物,对河口区及西部湖心区沉积物重金属人为污染特征进行分析;结合沉积岩芯210Pb年代结果,估算西部湖心区近150a来Ni、Cr、Cu、Zn、Pb等重金属元素的人为污染贡献量.结果表明,河口表层沉积物重金属污染具有显著的空间差异,南淝河河口重金属人为污染最重,其中Ni、Cr、Cu、Zn、Pb的人为污染贡献量分别为12.2、32.2、25.3、479.9和76.0 mg/kg,分别占总含量的35%、37%、64%、92%和77%;其次是柘皋河河口,主要重金属污染元素为Cu、Zn和Pb,人为污染贡献量达57.6、57.0和19.5 mg/kg,分别占总含量的73%、47%和36%;而派河、白石山河、杭埠河等河口表层沉积物中重金属元素人为污染程度较弱.巢湖西部湖心区主要污染元素为Cu、Zn、Pb,人为污染开始于1950s,1980年以来其人为污染贡献量显著增加,平均为16.2、245.6、47.8 mg/(m2.a),分别占各元素沉积通量的23%、61%和37%;Ni人为污染开始于1980s初期,人为污染贡献量平均为12.6 mg/(m2.a),占其沉积通量的13%左右;Cr基本未受人为污染影响.西部湖心区沉积岩芯及南淝河河口表层沉积物中重金属污染程度均表现为Zn>Pb>Cu,而且南淝河河口沉积物重金属污染程度显著高于西部湖心区.结合主要入湖河流径流量与河口沉积物重金属污染特征,认为巢湖西部湖心区重金属污染主要通过南淝河输入,来自合肥等城市的废水是主要的污染源.