Heavy metals partitioning in sediments of the Kabini River in South India

Cu, Cr, Fe, Mn, Ni, Pb, and Zn in the sediments of the Kabini River, Karnataka, India was studied to determine the association of metal with various geochemical phases by sequential extraction. The variations of heavy metal concentration depend on the lithology of the river basin and partly on anthropogenic activities. The Kabini River sediments are dominated by Sargur supracrustals with amphibolites, gneisses, carbonates, and ultrabasic rocks weathering into gneissic and serpentine soils carrying a natural load of cationic heavy metals. The source of heavy metals in the Kabini riverbed sediments is normally envisaged as additional inputs from anthropogenic over and above natural and lithogenic sources. Geochemical study indicates the metals under study were present mostly in the least mobilizable fraction in the overlying water and it is concluded that heavy metals in these sediments are to a great extent derived from multisource anthropogenic inputs besides geochemical background contributions The results show that lead and chromium have higher potential for mobilization from the sediment due to higher concentration at the exchangeable ion and sulfide ion bounded, also Cu and Pb have the greatest percentage of carbonate fraction, it means that the study area received inputs from urban and industrial effluents. Association of the Fe with organic matter fraction can be explained by the high affinity of these elements for the humic substances. Further, Zn and Ni reveal a significant enrichment in sediment and it is due to release of industrial wastewater into the river. These trace metals are possible contaminants to enter into aquatic and food chain.     

Heavy metal concentrations in water, suspended matter, and sediment from Gökova Bay, Turkey

The contents of heavy metals (Fe, Mn, Pb, Cu, Cd, and Hg) dissolved in water and suspended solids of Gökova Bay—partly and fully sampled in 2005 and 2006, respectively—are quite higher than the average values encountered in uncontaminated sea water. The high concentrations are associated with terrestrial inputs from the mining zones and anthropogenic (domestic + industrial) sources. Moreover, the distribution of Fe and Cu is affected by primary production because these elements function as nutrients in biological activities. The Cr, Ni, and Fe concentrations of surface sediments are above the shale average. The Cr and Ni contents of surface sediments representative of river mouths strongly correlate with total phosphorus contents. In a sulfide-poor environment, Pb and Cu were concentrated at a higher ratio in surface sediments than Cd, probably due to higher stabilities of their surface complexes with amorphous iron oxides and clay minerals existing as major components in the sediments. The exceptional enrichment of Zn may be attributed to double oxide formation with amorphous iron oxides in sediments. The high metal values are most probably caused by terrestrial inputs from anthropogenic sources and the mining zones at the southeast part of the bay. The Al, Mn, Pb, Cu, Zn, and Hg contents are below the shale average. The low values have possibly originated from the coarse-grained sandy sediments having a low affinity for metals. There are no distinct differences in the metal distributions in water and suspended matter between the years 2005 and 2006 in the bay, probably due to low sedimentation rates.     

An assessment of heavy metal contamination in soils of fresh water aquifer system and evaluation of eco-toxicity by lithogenic implications

The chemistry of heavy metals in sediments with respect to bio-availability and chemical reactivity is regulated by pH, texture, and organic matter contents of the sediments and specific binding form and coupled reactivity of the metals within. To focus on the metal distribution (Fe, Mn, Pb, Cd, Zn, Co, Cu, and Cr) and behavior in a fresh water aquifer system along with the ecological toxicity parameters, a four-step sequential extraction method was applied on 18 Eastern Ghats’ type sediments from fluorosis-hit Nayagarh district, India. Geo-accumulation index of metals in the sediments indicates that they are practically uncontaminated and/or less contaminated with and Fe, Mn, and Cu; contaminated to moderately contaminated with Pb, Zn, and Cr; and strongly contaminated with Cd. Rather, more than 80 % recovered Cd metal concentration in sediments constitute the labile fractions. Temporal clustering of metal fractions indicates transition metal fraction distribution claiming the sediment pH regulation. Similarly, base metal distribution accounts for organic carbon and soil conductivity due to their greater availability in exchangeable and sulfide fractions. Correlation analysis and factor analysis scores demonstrate lack of inter-relationship between transition group and base metal fractions. High fluoride concentration in ground water is associated with high sodium-bicarbonate-iron affinity with elevated pH values (i.e., >7.0) and high positive factor score with the total iron concentration in ground water.     

北方某水库表层沉积物重金属的赋存形态及其环境影响因子分析

为了解北方某水库重金属污染状况,采用BCR连续提取法对该水库表层沉积物中Cu、Pb、Zn、Cd的赋存形态进行了分析,对其含量及空间分布进行了研究,结合重金属总量讨论了各元素的潜在环境风险。结果表明,该水库表层沉积物中Cu、Pb、Zn、Cd的平均质量比分别为65.20 mg/kg、36.69 mg/kg、137.5 mg/kg、2.38 mg/kg,与该地区土壤元素背景值、该地区水系沉积物平均值及全国水系沉积物平均值相比,4种重金属元素均有一定程度的累积,其中Cd累积最为严重。形态分析结果表明,Cd主要以醋酸可提取态及可还原态存在,具有很高的环境风险;Pb主要以极高比例的可还原态存在,潜在风险较高;Zn和Cu存在较大比例的酸可提取态及可还原态,也具有一定程度的潜在风险。各元素生物有效性即可提取态含量排序为:Cd>Cu>Pb>Zn。     

Assessment of heavy metal enrichment in the offshore fine-grained sediments of the Caspian Sea

Sampling of the offshore seabed sediments of southwestern part of the Caspian Sea was carried out by gravity corer in order to study heavy metal concentration and the physicochemical factors controlling their distribution in the fine-grained fraction. The grain size distribution, amount, and type of clay minerals, total organic carbon (TOC) content, and Eh–pH of the sediments were determined. The average concentrations of the heavy metals in ppm are Mn (563), Cu (207.5), Sr (187), Zn (94), Pb (26.3), Ni (14.5), Co (11.5), Cd (2.56), and Ag (1.04) in their order of abundances. Co and Zn mostly indicate increase in silt-size fraction of the sediments suggesting their probable detrital provenance but the Mn, Ni, Cu, Sr, Pb, Cd, and Ag concentrations show a similar trend to distribution of the clay-size fraction. The concentrations of Mn, Co, and Cd increase with increase in the TOC content but the Cu, Pb, Ni, Ag, and Sr concentrations decrease with increase of the TOC content. The amounts of Zn, Cu, Sr, Pb, Cd, and Ag increase with increase in the CaCO₃ content. The calculated enrichment factor indicates that the sediments are very strong to extremely enriched in Ag, significantly enriched in Cu and Cd, and depleted to mineral for Pb, Sr, Co, Ni, and Zn. Variations of the Cu, Sr, Cd, Ag, and Pb concentrations are similar to the clay and CaCO₃ distributions.     

Enhanced anthropogenic heavy metal dispersal from tidal disturbance in the Jiaozhou Bay, North China

Heavy metal contamination in surface sediments of the Jiaozhou Bay was investigated in this study. Sediment sample was collected from the Jiaozhou Bay and its rivers. Heavy metal concentration was determined by inductively coupled plasma atomic emission spectroscopy and graphite furnace atomic absorption spectrometry. The result shows that river sediment in the east coast of the Jiaozhou Bay was heavily polluted especially for the Cu, Pb, Cd, and Zn. A slightly increase of heavy metal concentration was observed at stations near the east coast in the Jiaozhou Bay; however, contaminated sediment from polluted river was constrained mostly near shore within 3–4 km. Downstream decrease of heavy metals in river mouth suggested dilution from strong tidal current. Rapid seaward decline in the east coast and alongshore band dispersal pattern of heavy metals in surface sediment indicated mixing and remobilizing enhanced by large tidal range that regulated dispersal of sediments and anthropogenic heavy metals in the Jiaozhou Bay area.     

Heavy metal contamination in a vulnerable mangrove swamp in South China

Concentrations of six heavy metals (Cu, Ni, Zn, Cd, Cr, and Pb) in sediments and fine roots, thick roots, branches, and leaves of six mangrove plant species collected from the Futian mangrove forest, South China were measured. The results show that both the sediments and plants in Futian mangrove ecosystem are moderately contaminated by heavy metals, with the main contaminants being Zn and Cu. All investigated metals showed very similar distribution patterns in the sediments, implying that they had the same anthropogenic source(s). High accumulations of the heavy metals were observed in the root tissues, especially the fine roots, and much lower concentrations in the other organs. This indicates that the roots strongly immobilize the heavy metals and (hence) that mangrove plants possess mechanisms that limit the upward transport of heavy metals and exclude them from sensitive tissues. The growth performance of propagules and 6-month-old seedlings of Bruguiera gymnorhiza in the presence of contaminating Cu and Cd was also examined. The results show that this plant is not sufficiently sensitive to heavy metals after its propagule stage for its regeneration and growth to be significantly affected by heavy metal contamination in the Futian mangrove ecosystem. However, older mangrove seedlings appeared to be more metal-tolerant than the younger seedlings due to their more efficient exclusion mechanism. Thus, the effects of metal contamination on young seedlings should be assessed when evaluating the risks posed by heavy metals in an ecosystem.     

Groundwater environmental capacity and its evaluation index

At present, anthropogenic contribution of heavy metals far exceeds natural input in some aquatic sediment, but the proportions are difficult to differentiate due to the changes in sediment characters. In this paper, the metal (Al, Fe, K, Mg, Ca, Cr, Cu, Ni, and Zn) concentrations, grain size, and total organic carbon (TOC) content in the surface and core sediments of Nansihu Lake Catchment (the open lake and six inflow rivers) were determined. The chemical speciations of the metals (Al, Fe, Cr, Cu, Ni, and Zn) in the surface sediments were also analyzed. Approaches of factor analysis, normalized enrichment factor (EF) and the new non-residual fractions enrichment factor (K_NRF) were used to differentiate the sources of the metals in the sediments, from detrital clastic debris or anthropogenic input, and to quantify the anthropogenic contamination. The results indicate that natural processes were more dominant in concentrating the metals in the surface and core sediments of the open lake. High concentration of Ca and deficiency of other metals in the upper layers of the sediment core were attributed to the input of carbonate minerals in the catchment with increasing human activities since 1980s. High TOC content magnified the deficiency of the metals. Nevertheless, the EF and K_NRF both reveal moderate to significant anthropogenic contamination of Cr, Cu, Ni, and Zn in the surface sediments of Laoyun River and the estuary and Cr in the surface sediments of Baima River. The proportion of non-residual fractions (acid soluble, reducible, and oxidizable fractions) of Cr, Cu, Ni, and Zn in the contaminated sediments increased to 37–99% from the background levels less than 30%.     

贵州某流域城市河段沉积物及悬浮物重金属污染研究

通过在丰水期对贵州省某流域城市河段悬浮物和沉积物中的重金属含量进行测定,运用单因子指数法、生态风险评价法、因子分析法,初步探讨了该河段Cu、Zn、Pb、Hg、Cd、Cr、Ni及As等8种重金属元素的含量分布、污染特征、潜在生态风险及主要来源。检测结果显示,沉积物和悬浮物中Hg、Cd、Zn、Pb、As的平均含量较高,是贵州省土壤背景值的1.02～16.97倍。单因子指数评价结果表明：在沉积物中,Zn、Pb、As为轻度污染,Hg和Cd为重度污染;在悬浮物中,Cu、Pb、As为轻度污染,Zn为中度污染,Hg和Cd为重度污染。潜在生态风险指数评价结果显示,Hg和Cd的生态风险最大,为主要污染元素。研究区沉积物样品综合生态风险指数(RI)介于183.27～1 393.96,平均值为912.06,总体处于严重生态风险等级;悬浮物样品RI值介于341.53～612.38,平均值为436.85,总体处于重度生态风险等级。其中,沉积物样品重金属平均生态风险等级高于悬浮物样品,支流样品重金属生态风险等级总体上低于干流下游样品。根据因子分析法分析结果,初步推测沉积物及悬浮物Hg、Cd、Cr、Ni含量主要受工...     

Heavy metal concentrations in water and sediments in Tasik Chini, a freshwater lake, Malaysia

The purpose of this paper are to determine the concentration of heavy metals namely cadmium (Cd), copper (Cu) and lead (Pb) in water and sediment; and to investigate the effect of sediment pH and sediment organic matter on concentration of cadmium, copper and lead in sediment at oxidation fraction. For this purpose the concentration of heavy metals were measured in water and sediments at 15 sites from Tasik Chini, Peninsular Malaysia. The sequential extraction procedure used in this study was based on defined fractions: exchangeable, acid reduction, oxidation, and residual. The concentration of heavy metals in residual fraction was higher than the other fractions. Among the non-residual fractions, the concentration of heavy metals in organic matter fraction was much higher than other fractions collected from all sampling sites. The pH of the sediment in all sites was acidic. The mean pH ranges from 4.8 to 5.5 with the higher value observed at site 15. Results of organic matter analysis showed that the percentage of organic matter present in sediment samples varies throughout the lake and all sites of sediments were relatively rich in organic matter ranging from 13.0% to 34.2%. The highest mean percentage of organic matter was measured at sampling site 15, with value of 31.78%.     

Metal Pollution Assessment of Sediment and Water in the River Hindon, India

The metal pollution in water and sediment of the River Hindon in western Uttar Pradesh (India) was assessed for Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The metal concentrations in water showed wide temporal variation compared with bed sediment because of variability in water discharge and variations in suspended solid loadings. Metal concentrations in bed sediments provided a better evaluation of the degree and the extent of contamination in the aquatic environment, Santagarh and Atali being the most polluted sites of the river. The ratio of heavy metals to conservative elements (Fe, Al, etc.) may reveal the geochemical imbalances due to the elevated metal concentrations normally attributed to anthropogenic sources. Metal/Al ratios for the bed sediments of the river Hindon were used to determine the relative mobility and general trend of relative mobility occurred Fe > Mn > Zn > Cr > Ni > Pb > Cu > Cd.     

Fractionation and ecological risk of metals in urban river sediments in Zhongshan City, Pearl River Delta

Surface sediments collected from nine urban rivers located in Zhongshan City, Pearl River Delta, were analyzed for total concentration of metals with digestion and chemical fractionation adopting the modified European Community Bureau of Reference (BCR) sequential extraction procedure. The results showed that concentration and fractionation of metals varied significantly among the rivers. The total concentration of eight metals in most rivers did not exceed the China Environmental Quality Standard for Soil, Grade III. The potential ecological risk of metals to rivers were related to the land use patterns, in the order of manufacturing areas > residential areas > agriculture areas. The concentration of Pb in the reducible fraction was relatively high (60.0-84.3%). The dominant proportions of Cd, Zn and Cu were primary in the non-residual fraction (67.0%, 71.8% and 81.4% on average respectively), while the percentages of the residual fractions of Cr and Ni varied over a wide range (43-85% and 24-71% respectively). The approaches of the H?kanson ecological risk index and Secondary Phase Enrichment Factor were applied for ecological risk assessment and metal enrichment calculation. The results indicated Hg and Cd had posed high potential ecological risk to urban rivers in this region. Meanwhile, there was widespread pollution and high enrichment of Cu in river sediments in this region. Multiple regression analysis showed that five water quality parameters (pH, DO, COD(Mn), NH(4)(+)-N, TP) had little influence on the distribution of metal fractionation. This result revealed that the ecological risk of metals was not eliminated along with the improvement in water quality. Correlation studies showed that among the metals, Group A (Cd, As, Pb, Zn Hg, r = 0.730-0.924) and Group B (Cr, Cu, Ni, r = 0.815-0.948) were obtained, and the metal contaminations were from industrial activities rather than residential.     

Evaluating the efficiency of sediment metal pollution indices in interpreting the pollution of Haraz River sediments, southern Caspian Sea basin

The Haraz River is one of the most significant rivers in the southern Caspian Sea basin. Towards the estuary, the river receives discharges of industrial, agricultural, and urban wastes. In the present investigation, bulk concentrations of Cu, Zn, As, Cd, Pb, Fe, Ni, Cr, Co, and Sr in Haraz River (Iran) bed sediments were measured from several sample locations. In addition, association of studied metals with various sedimentary phases was assessed to determine the proportions of metals in different forms. The intensity of sediment contamination was evaluated using an enrichment factor (EF), geo-accumulation index (I_geo), and a newly developed pollution index (I_poll). Both EF and I_geo formulae compare present concentrations of metals to their background levels in crust and shale, respectively. In a specific area with its own geological background like Haraz River water basin where naturally high concentrations of metals may be found, such a comparison may lead to biased conclusions regarding levels of anthropogenic contamination. Accordingly, chemical partitioning results are substituted for the mean crust and shale levels in the new index (I_poll). The Pearson correlation coefficient between the anthropogenic portion of metallic pollution in Haraz river-bed sediments with I_poll showed much more value in comparison with those of geochemical accumulation index and enrichment factor. The order of metals introduced by anthropogenic activities are as follows: Sr > Pb > Co > Cd > Zn > Cu > Ni > As > Cr > Fe. The results showed relatively higher concentrations of Cd, As, Sr, and Pb in comparison with those of shale. However, based on the chemical partitioning of metals, it is found that Sr, Pb, Co, and Cd are the most mobile metals. In spite of the high As concentrations in sediments, it is not likely that this element is a major hazard for the aquatic environment since it is found mainly in the residual fraction. Also, Fe, Cr, and Ni are present in the greatest percentages in the residual fraction, which implies that these metals are strongly linked to the sediments.     

镇江内江底泥重金属分布特征及潜在生态危害评价

对镇江内江的底泥进行采集,测定底泥中的Cu、As、Hg、Cr、Pb、Cd、Zn、总磷、总氮、有机质的含量,采用潜在生态风险评价和相关性分析的方法,研究了底泥中重金属的污染水平、生态危害、分布特征和溯源。结果表明,(1)内江底泥中的重金属污染主要为Hg、Cd、As。各重金属单项潜在生态危害指数大小关系为Hg>Cd>As>Pb>Cu>Cr>Zn。(2)内江的整体生态环境受重金属的危害程度处在中等水平,重金属的生态威胁主要来自Hg,建议在达到强生态威胁程度的3#、8#、20#、21#采样点附近清理淤泥。(3)由重金属分布特征可知,湿地生态系统对重金属具有较好的吸附去除作用;在内江流速慢、死水多的地方易造成重金属富集;入江河口重金属富集也较明显;污染企业与重金属含量有直接关系。(4)由相关性探源可知,Cu、Zn、Cr主要来自于自然界,Hg、Cd、Pb主要来自于企业污水排放,As则来自于自然界和人为排放。     

Assessment of heavy metals in sediments from a typical catchment of the Yangtze River, China

An intensive investigation was conducted to study the accumulation, speciation, and distribution of various heavy metals (As, Cd, Cr, Cu, Hg, Ni, Pb, and Zn) in sediments from the Yangtze River catchment of Wuhan, China. The potential ecological risks posed by these heavy metals also were estimated. The median concentrations of most heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn) were higher than the background values of soils in Wuhan and were beyond the threshold effect level (TEL), implying heavy metal contamination of the sediments. Carbonate-bound Cd and exchangeable Cd, both of which had high bioavailability, were 40.2% and 30.5% of the total for Cd, respectively, demonstrating that Cd poses a high ecological risk in the sediments. The coefficients of the relationship among Pb, Hg, and Cu were greater than 0.797 using correlation analysis, indicating the highly positive correlation among these three elements. Besides, total organic carbon content played an important role in determining the behaviors of heavy metals in sediments. Principal component analysis was used to study the distribution and potential origin of heavy metals. The result suggested three principal components controlling their variability in sediments, which accounted for 36.72% (factor 1: Hg, Cu, and Pb), 28.69% (factor 2: Cr, Zn, and Ni), and 19.45% (factor 3: As and Cd) of the total variance. Overall, 75% of the studied sediment samples afforded relatively low potential ecological risk despite the fact that generally higher concentrations of heavy metals relative to TEL were detected in the sediments.     

长江南京段近岸沉积物和土壤中重金属分布特征分析

通过测定沉积物和土壤中Cd、Pb、Cr、Zn、Cu、Ni 6种重金属元素的平均含量,计算其富集因子,分析长江南京段近岸沉积物和土壤中重金属的空间分布特征,结果表明,几种重金属在沉积物中的富集次序为:CdPbCr1NiCuZn,在土壤中为:CdZnCu1CrPbNi,除Zn和Cu外,其他几种金属在沉积物中的富集程度高于土壤,同时Cd的含量超过土壤环境质量三级标准。以Cd和Pb为例分析了重金属含量与沉积物粒级之间的关系,回归分析显示,Cd、Pb的含量与颗粒物的粒级呈显著的相关性,与细颗粒物的含量有密切关系,细颗粒携带的重金属,在长江水力分选作用下到达下游,成为沉积物中重金属的主要来源。     

An approach to partition the anthropogenic and natural components of heavy metal accumulations in roadside agricultural soil

This paper describes a new approach that allows us to partition the anthropogenic and natural contributions to heavy metal accumulations in roadside agricultural soils. This approach, combining trend analysis and multivariate statistical analysis, partitions total heavy metals into three components: anthropogenic, natural, and unexplained residual. The approach was applied in a case study in Yixing City, China, to determine the spatial distributions of heavy metal accumulations. The results show that anthropogenic components of Pb, Cu, Zn, and Cd account for 52.4%, 23.04%, 5.09%, and 10.9% of total content, respectively. Spatial distributions of anthropogenic components are characterized by decreasing accumulation with increasing distance from the road. Ranges of influence of traffic for Pb, Cu, and Cd are beyond 300 m, whereas the range of Zn is less than 200 m. The spatial distributions of the four elements?? natural components show relatively similar distribution patterns. Assessments of variable partition methods show that the predicted values of Pb, Cu, Zn, and Cd are consistent with their measured values. The anthropogenic components extracted from total contents of heavy metal will be useful for modeling heavy metal accumulations produced by human activities.     

Heavy metal and polycyclic aromatic hydrocarbons in Ebrié lagoon sediments, Côte d’Ivoire

Surface sediments throughout Ebrié lagoon, Côte d’Ivoire were collected in 2001 and analyzed for their heavy metal and polycyclic aromatic hydrocarbons (PAH) contaminant content. Geochemical maps of heavy metals (Cd, Cu, Zn, Fe, and Mn) in the surface sediment were produced based on geographical information system (GIS) technology. Heavy metals and PAH were detected at high concentration and provide evidence for several anthropogenic inputs to the lagoon. A significant spatial relationship was found for Fe, Zn, and Cu in the sediment using a GIS-based analysis, suggesting that these metal contaminants in the sediments of the Biétri bay had common sources.     

Impact of anthropogenic input on physicochemical parameters and trace metals in marine surface sediments of Bay of Bengal off Chennai, India

The study of heavy metal distribution in coastal surface sediments is an important component in understanding the exogenic cycling as well as in assessing the effect of anthropogenic influences on the marine ecosystem. In this study, surface sediment samples were collected from five different traverses along the innershelf of Bay of Bengal, off Chennai, India during pre- and post-monsoon seasons. The results of Spearmen correlation matrix, factor and cluster analysis, enrichment and contamination factor analysis, and geoaccumulation index of the heavy metals analyzed in the collected surface sediment were discussed. The level of both enrichment and contamination factor are shown in following order Cd > Cu > Cr > Ni > Pb > Co > Zn > Mn > Fe > Hg. The geoaccumulation index suggests that Cd and Cu are strongly to extremely pollute the sediments in both seasons. The results strongly indict anthropogenic sources for moderate input of Cd and Cu in to the innershelf of Chennai coast.     

Speciation and assessment of heavy metals in surface sediments of Jinjiang River tidal reach, southeast of China

The concentration and speciation of heavy metals (Cr, Ni, Cu, Zn, Cd, Pb) in surface sediments (??≤ 63 μm) of Jinjiang River tidal reach are determined to evaluate the metal behavior. A modified BCR three-step sequential extraction procedure is carried out, and the residual fraction is undertaken by microwave-assisted acid digestion. The index of geo-accumulation indicates that Cd appeared highest among all these heavy metals in surface sediments, Cr, Cu, Zn lower, and Ni, Pb the least. The percentage of Zn, Cd is comparatively higher in the acid soluble fraction, Pb and Cu higher in the reductive fraction, indicating larger potential danger to the environment. So it is essential for developing the future remediation plans and pollution control strategies.