Heavy metals in sediments of the Tecate River, Mexico

Ten sites along the Tecate River, Mexico were sampled to evaluate the cadmium, lead, nickel and chromium concentrations in sediments. The result shows contamination for cadmium in most of the sites, where two sites were class 4 (polluted to strongly polluted) according to geoaccumulation index proposed by Muller. Two sites were found polluted for all the heavy metals analyzed (Cr, Cd, Pb and Ni), indicating the effect of anthropogenic activities. A correlation between Ni and Cd concentration had been found indicating a common source. These metals are usually used in electroplating industry. The results of this study can be used for decision makers to prioritize measures to control the pollution for these metals.     

Recent changes in heavy metal storage in flood-plain soils of the Lahn River,central Germany

Between 1995 and 2007, the concentrations of Pb and Zn in floodplain soils increased along a 60-km reach of the Lahn River, Germany, suggesting that the storage of some metals in the fluvial system is out of phase with recent declines in the release of metals to the environment. Re-sampling of surface soils to 5 cm along five transects perpendicular to the river indicated that the concentration of Pb increased between 1995 and 2007 along two transects and was statistically unchanged at the other three. The concentration of Zn increased at three of five transects and was statistically unchanged at two transects over the same time period. Between 1995 and 2007, concentrations of Cu were statistically equal along four of five transects and declined at the other transect. The increase in Pb and Zn was greater in a more rural than in a more urbanized reach of the Lahn River. Soil texture and organic matter content had virtually no impact on the concentration of metals. The increase in Pb concentration suggests a lag between the decline in Pb releases to the environment and its movement through the fluvial system. Increased Zn storage may result from the high solubility of the metal and the relative ease with which it moves through the environment. Environmental controls appear to have slowed Cu storage along the Lahn River, but are not yet reflected in Pb and Zn storage.     

Competitive adsorption,release and speciation of heavy metals in the Yellow River sediments,China

The competitive adsorption and the release of selected heavy metals and their speciation distribution before and after adsorption in the Yellow River sediments are discussed. The adsorption of metals onto sediments increases with increasing pH value and decreases with increasing ionic strength. The competitive coefficient K _c and the distribution coefficient K _d are obtained to analyze the competitive abilities of selected heavy metals, which are ranked as Pb > Cu >> Zn > Cd. The competition among selected heavy metals becomes more impetuous with increasing ion concentration in water. Speciation analysis was done by an improved analytical procedure involving five steps of sequential extraction. Cu, Pb and Zn were mainly transformed into the carbonate-bound form (50.8–87.7%) in adsorption. Most of (60.7–77.3%) Cd was transformed into the exchangeable form, and the percentage of carbonate-bound Cd was 19.7–30.4%. The release reaction was so quick that the release capacity of selected heavy metals from sediments to aqueous solution reached half of the maximum value only in 30 s. As opposed to adsorption, the release capacities of selected heavy metals were ranked as Cd > Zn >> Cu > Pb. In this study, Cd produces the most severe environmental hazards, because its concentration in the release solution is 85.8 times more than the human health criteria of US EPA.     

Spatial variations in heavy metals on tidal flats in the Yangtze Estuary,China

Surface samples are used to determine onshore-offshore variations in heavy metal concentrations on tidal flats on Chongming and Hengsha Islands in the Yangtze Estuary, China. The Mann-Whitney U-Test suggests that proximity to the estuarine turbidity maximum does not result in significantly higher metal concentrations on tidal flats. Principal Components Analysis shows that grain-size is the primary control on metal concentrations, reflecting the occurrence of salt marsh and mud and sand flats. Sediment quality is comparable to that of pristine estuaries because of dilution by high river sediment loads.     

Heavy metals distribution and fractionation in sediments of the Mahanadi River basin, India

Heavy metals distribution in core sediments, different size fractions of bed sediments (>212 urn, 90-212 jam, 63–90 urn, 53–63 urn, < 53 urn), and suspended sediments (>30 urn, 20–30 m, 10–20 urn, 2–10 urn, <2 m) have been discussed. Pb, Zn, and Cr have been accumulating in recent years in the sediments. Si, Al, Fe, Ca, and Mg dominate the bed and suspended sediment composition. Metals show increasing concentrations in finer sediments. Applying multivariate analysis to sediment composition, metals have been grouped into different factors depending upon their source of origin. Chemical fractionation studies on suspended and bed sediments show Fe, Zn, Cu, and Pb are associated with the residual fraction and Mn with the exchangeable fraction.     

Risk assessment of heavy metals in topsoil along the banks of theYangtze River in Huangshi,China

High concentrations of heavy metal in farmland threatens food production and human health. Our study assesses soil quality and the distribution of Cd, Cr, Cu, Zn, Pb and Ni, to identify possible sources of heavy metals along the banks of the Yangtze River in Huangshi. Heavy metal concentrations of 22 topsoil samples were measured using the inductively coupled plasma mass spectrometry instrument and data was analyzed by multivariate statistic approaches. Heavy metal contamination risk assessment was performed using a combination of the Nemerow multi-factor index method, the Hakanson potential ecological risk index method and the Muller index of geo-accumulation method. These methods determined similar results indicating that cadmium (Cd) poses a health risk to residents at the study site while Cr, Cu, Zn, Pb and Ni do not. The Nemerow multi-factor index method demonstrated that 18 samples were heavily polluted, three moderately polluted and one lightly polluted. The Muller index of geo-accumulation method found ten samples were moderately to strongly polluted by Cd, five were moderately polluted, six were lightly to moderately polluted and one was lightly polluted. The Hakanson potential ecological risk index method proved six samples were strongly polluted, seven were moderately polluted and nine were lightly polluted. Since our sampling sites were all in agricultural lands, we recommend the potential ecological risk index method as the most effective given it not only considers the range of pollutants contributing to soil pollution but factors in heavy metals toxicity. We are apt that the source of the high concentrations of Cd found in topsoil is derived from alluvial sediments upstream of the Yangtze River with a high percentage of residual speciation and a low percentage of exchangeable speciation distribution of Cd. This in turns indicates that a high concentration of Cd in soil had little impact on the natural environment. However, 31.9% of the iron-manganese oxides bound speciation indicating that such levels of Cd in soil would be potentially hazardous to the crops, particularly if exposed to a reductive condition.     

Distribution and assessment of sediment toxicity in Tamaki Estuary,Auckland, New Zealand

Heavy metal levels in surface sediments from Tamaki Estuary demonstrate significant up estuary increases in Cu, Pb, Zn, Cd and mud concentrations. Increased metal levels towards the head of the estuary are linked to local catchment sources reflecting the historical development, industrialisation and urbanisation of catchment areas surrounding the upper estuary. The relatively narrow constriction in the middle estuary (Panmure area), makes it susceptible to accumulation of upper estuary pollutants, since the constriction reduces circulation and extends the time required for fine waterborne sediments in the upper estuary to exchange with fresh coastal water. As a result fine fraction sediments trapped in the upper estuary facilitate capture and retention of pollutants at the head of the estuary. The increase in sandy mud poor sediments towards the mouth of the estuary is associated with generally low metal concentrations. The estuary’s geomorphic shape with a mid estuary constriction, sediment texture and mineralogy and catchment history are significant factors in understanding the overall spatial distribution of contaminants in the estuary. Bulk concentration values for Cu, Pb, Zn, and Cd in all the studied surface samples occur below ANZECC ISQG-H toxicity values. Cd and Cu concentrations are also below the ISQG-L toxicity levels for these elements. However, Pb and Zn concentrations do exceed the ISQG-L values in some of the surface bulk samples in the upper estuary proximal to long established sources of catchment pollution.     

Concentration distribution and assessment of several heavy metals in sediments of west-four Pearl River Estuary

Grain size parameters, trace metals (Co, Cu, Ni, Pb, Cr, Zn, Ba, Zr and Sr) and total organic matter (TOM) of 38 surficial sediments and a sediment core of west-four Pearl River Estuary region were analyzed. The spacial distribution and the transportation procession of the chemical element in surficial sediments were studied mainly. Multivariate statistics are used to analyses the interrelationship of metal elements, TOM and the grain size parameters. The results demonstrated that terrigenous sediment taken by the rivers are main sources of the trace metal elements and TOM, and the lithology of parent material is a dominating factor controlling the trace metal composition in the surficial sediment. In addition, the hydrodynamic condition and landform are the dominating factors controlling the large-scale distribution, while the anthropogenic input in the coastal area alters the regional distribution of heavy metal elements Co, Cu, Ni, Pb, Cr and Zn. The enrichment factor (EF) analysis was used for the differentiation of the metal source between anthropogenic and naturally occurring, and for the assessment of the anthropogenic influence, the deeper layer content of heavy metals were calculated as the background values and Zr was chosen as the reference element for Co, Cu, Ni, Pb, Cr and Zn. The result indicate prevalent enrichment of Co, Cu, Ni, Pb and Cr, and the contamination of Pb is most obvious, further more, the peculiar high EF value sites of Zn and Pb probably suggest point source input.     

Mercury,arsenic, antimony,and selenium contents of sediment from the Kuskokwim River,Bethel, Alaska,USA

The Kuskokwim River at Bethel, Alaska, drains a major mercury-antimony metallogenic province in its upper reaches and tributaries. Bethel (population 4000) is situated on the Kuskokwim floodplain and also draws its water supply from wells located in river-deposited sediment. A boring through overbank and floodplain sediment has provided material to establish a baseline datum for sediment-hosted heavy metals. Mercury (total), arsenic, antimony, and selenium contents were determined; aluminum was also determined and used as normalizing factor. The contents of the heavy metals were relatively constant with depth and do not reflect any potential enrichment from upstream contaminant sources.     

Heavy metal pollution in freshly deposited sediments of the Yamuna River (the Ganges River tributary): a case study from Delhi and Agra urban centres, India

 The Yamuna River sediments, collected from Delhi and Agra urban centres, were analysed for concentration and distribution of nine heavy metals by means of atomic adsorption spectrometry. Total metal contents varied in the following ranges (in mg/kg): Cr (157–817), Mn (515–1015), Fe (28,700–45,300), Co(11.7–28.4), Ni (40–538), Cu (40–1204), Zn (107–1974), Pb (22–856) and Cd (0.50–114.8). The degree of metal enrichment was compared with the average shale concentration and shows exceptionally high values for Cr, Ni, Cu, Zn, Pb and Cd in both urban centres. In the total heavy metal concentration, anthropogenic input contains 70% Cr, 74% Cu, 59% Zn, 46% Pb, 90% Cd in Delhi and 61% Cr, 23% Ni, 71% Cu, 72% Zn, 63% Pb, 94% Cd in Agra. A significant correlation was observed between increasing Cr, Ni, Zn, and Cu concentrations with increasing total sediment carbon and total sediment sulfur content. Based on the Müller's geoaccumulation index, the quality of the river sediments can be regarded as being moderately polluted to very highly polluted with Cr, Ni, Cu, Zn, Pb and Cd in the Delhi and Agra urban centres. The present sediment analysis, therefore, plays an important role in environmental measures for the Yamuna River and the planning of these city centres. Received: 21 June 1999 · Accepted: 1 October 1999     

Distribution of heavy metals in the Piscinas beach sediments (SW Sardinia, Italy)

We have studied sediments of the Piscinas beach (SW Sardinia, Italy), which is supplied by two streams that wash mine dumps of abandoned lead and zinc mines at Montevecchio and Ingurtosu, situated inland from the supply basin of the beach itself. A study of the texture, mineralogy and geochemistry of the sediments was conducted for the purpose of assessing the possible influence of the mine waste on the composition of the sediments, looking for any anomalous enrichments in heavy metals. Furthermore, to evaluate and quantify metal release into the sea, samples of Posidonia oceanica, a bioaccumulator marine plant, were also examined. The results indicate that the distribution of heavy metals in the foreshore sediments is particularly affected by the contribution of the streams, while in the shoreface the distribution is affected by the currents that disperse the sediments both out to sea and southwards. The metal contents of the Posidonia oceanica are correlated with the different stages of activity of the mines. Received: 28 January 1998 · Accepted: 22 April 1998     

Groundwater geochemistry,hydrogeology and potash mineral potential of the Lake Woods region,Northern Territory,Australia

We collected 38 groundwater and two surface-water samples in the semi-arid Lake Woods region of the Northern Territory to better understand the hydrogeochemistry of this system, which straddles the Wiso, Tennant Creek and Georgina geological regions. Lake Woods is presently a losing waterbody feeding the underlying groundwater system. The main aquifers comprise mainly carbonate (limestone and dolostone), siliciclastic (sandstone and siltstone) and evaporitic units. The water composition was determined in terms of bulk properties (pH, electrical conductivity, temperature, dissolved oxygen, redox potential), 40 major, minor and trace elements, and six isotopes (δ¹⁸O_water, δ²H_water, δ¹³C_DIC, δ³⁴S_SO4^2–, δ¹⁸O_SO4^2–, ⁸⁷Sr/⁸⁶Sr). The groundwater is recharged through infiltration in the catchment from monsoonal rainfall (annual average rainfall ～600?mm) and runoff. It evolves geochemically mainly through evapotranspiration and water–mineral interaction (dissolution of carbonates, silicates and to a lesser extent sulfates). The two surface waters (one from the main creek feeding the lake, the other from the lake itself) are extraordinarily enriched in ¹⁸O and ²H isotopes (δ¹⁸O of +10.9 and +16.4‰ VSMOW, and δ²H of +41 and +93‰ VSMOW, respectively), which is interpreted to reflect evaporation during the dry season (annual average evaporation ～3000?mm) under low humidity conditions (annual average relative humidity ～40%). This interpretation is supported by modelling results. The potassium (K) relative enrichment (K/Cl^– mass ratio over 50 times that of sea water) is similar to that observed in salt-lake systems worldwide that are prospective for potash resources. Potassium enrichment is believed to derive partly from dust during atmospheric transport/deposition, but mostly from weathering of K-silicates in the aquifer materials (and possibly underlying formations). Further studies of Australian salt-lake systems are required to reach evidence-based conclusions on their mineral potential for potash, lithium, boron and other low-temperature mineral system commodities such as uranium.     

Granulometric and chemical composition of the Sava River sediments upstream and downstream of the Krsko nuclear power plant

Total concentrations of 13 elements (K, Ca, Ti, Cr, Mn, Fe, Cu, Zn, Rb, Sr, Y, Zr, Pb) in the size-fractionated Sava River sediments upstream and downstream of the Krsko nuclear power plant together with metal speciation within bulk sediment have been investigated. Trace metals generally increase with decreasing particle size, however, because of entrapment of organic matter in the 0.63–1 mm fraction, concentrations in the coarser sediment fraction are higher than expected. Exchangeable Pb, Zn, Cu, Mn, Cr and Fe are generally found to represent a negligible fraction of the total metal concentration of the bulk sediment. Seasonal variations of the Pb, Zn and Cu concentrations in the <0.5 mm fraction reflect decreased values during the spring period. Heavy metal concentrations in the 2003 waste water discharges from the Krsko nuclear power plant released into the Sava River were much lower than their maximum allowed values. Combined rubidium and organic matter normalization of the Zn, Pb and Cu concentrations, which was applied on the minus 0.063 mm fraction, indicated three potential sources of contaminants.     

Magnetic signature of heavy metals pollution of sediments: case study from the East Lake in Wuhan,China

Detailed magnetic measurements and geochemical analyses were performed on 114 sediment samples collected from the East Lake, Wuhan city, China, to establish a possible link between the enhanced concentration of anthropogenic magnetic particles and heavy metals with known sources. Relatively higher magnetic susceptibility values (mass-specific, χ, >150 × 10⁻⁸ m³ kg⁻¹) were observed for samples near the pollution sources: e.g. the Wuhan Iron and Steel Company (WISC), the Qingshan Thermal Power Plant (QTPP), the banks (driveways) of the lake and near the sightseeing route of yachts on the lake. Moreover, χ is positively correlated to the concentration of Pb (correlation coefficient r = 0.682), but negatively or weakly correlated with both Zn and Cu. In contrast, anhysteretic remanent magnetization (ARM) is significantly correlated with these major heavy metals (r = 0.645 for Zn–ARM, 0.699 for Pb–ARM and 0.841 for Cu–ARM, respectively), which indicate that ARM serves a better indicator for the pollution of heavy metals in this lake. Thermomagnetic analysis combined with magnetic hysteresis measurements revealed that magnetites in the pseudo-single-domain/multidomain grain-size regions are dominant. Scanning electron microscopy and energy dispersive X-ray examinations of the magnetic extracts showed that these Fe-rich particles have different morphologies: orange-peel structure, hollow structure with adhered smaller particles, Zr-rich melted-like irregular particles, pear-shaped spherules and spherules with slick surfaces. These features are typical for particles produced by anthropogenic activities. Because of the genetic relationship between the environmental setting of the East Lake and the nearby pollution sources, this study suggests that in situ magnetic surveys are sensitive to evaluate the environmental pollution on the lake bottom.     

Accumulation of muds and metals in the Hudson River estuary turbidity maximum

 In the Hudson River estuary, fine mud and toxic metals are enriched in the upstream turbidity maximum. The mechanisms causing the enrichment were assessed through the analysis of suspended-sediment concentration (SSC) (bottom and surface), particle size, and trace metal distributions. Bottom SSCs varied across the study area by a factor of ten, and the turbidity maximum activity was observed in between kilometers 45 and 80. The particle-size analysis defined two accumulation modes: <4.65 and >22.1 μm. The ratio of the fine-to-coarse mode increased from 1.75 to 2.75 in the turbidity maximum. The fine mud concentration (55–60%) in the turbidity maximum was found to have a high correlation (r=0.98;p<0.005) with the concentration of <2-μm particles. A conceptual model was derived in order to understand the possible mechanisms by which fine mud (and specifically <2-μm particles) is concentrated. The two dominant size modes were analyzed for toxic metals. The upstream tributaries are major sources of metals compared to point sources at downstream locations. In the turbidity maximum, Cd, Cu, Zn, and Pb are significantly enriched compared to average shale metal values and ERM toxicity guidelines by 580, 42, 10, 16 and 12, 7, 2.4, 1.4 times, respectively. Decreasing metal concentrations downstream of the turbidity maximum imply that Haverstraw Bay acts as temporary storage for fine particles and enriched metals. It is demonstrated in this study that toxic metals are enriched in Haverstraw Bay due to the mud accumulation. The high levels of toxic metals in the sediments of the Hudson River estuary are a major concern because human activities (dredging and river traffic) cause resuspension of sediments and can change the mobility patterns of bioavailable contaminants. Received: 4 June 1997 · Accepted: 9 September 1997     

Accumulation of heavy metals in Oostriku peat bog,Estonia: -site description,conceptual modelling and geochemical modelling of the source of the metals

Oxidation of sulphides leads to the dissolution of metals, which are transported with water and accumulate at geochemical barriers. Such barriers can form in peat bogs. This paper gives an introduction into the long-term processes in Oostriku peat bog where high accumulations of heavy metals are observed. Peat and water samples are analysed for Fe, As and heavy metals (Cd, Cu, Mn, Ni, Pb and Zn) using different methods. A concept is based on the observations. Metals are leached by sulphide oxidation in the carbonate rocks upstream of the peat. The water feeds the peat from below. The metals are sorbed and precipitated in the peat. The sulphide oxidation is simulated to examine the origin and metal speciation in the water. The simulated solution is compared with the groundwater entering the peat. The results showed a fair agreement for the major constituents. There were considerable differences for species with low concentrations.     

The distribution of heavy metals in an abandoned mining area; a case study of Strauss Pit, the Drake mining area, Australia: implications for the environmental management of mine sites

Surface water samples from the Drake mining area show elevated metal concentrations, notably cadmium, iron and zinc. A detailed study of a sphalerite /quartz vein from Strauss Pit and chalcopyrite and pyrite from the Adeline mine and Strauss Pit indicate that micro-scale analyses of ores are necessary for environmental management of mine sites. Analyses show that Cd is elevated, up to 2.1 % by weight, and is associated with sphalerite, replacing Zn, or to a lesser extent replacing Pb within small galena grains. High concentrations of Cu are also associated with the Strauss Pit ore as small chalcopyrite grains along the margins of the sphalerite vein, within the central quartz zone of the vein system, and as replacement rims on sphalerite grains. Chalcopyrite from the Adeline mine area, is by comparison, metal poor, but still contains elevated heavy metal concentrations. Whereas, pyrite and chalcopyrite, from Strauss Pit have variable heavy metal concentrations, with chalcopyrite from within sphalerite veins having higher Cd and Zn concentrations than chalcopyrite distal to the veins. Cadmium and other heavy metals within the ores are mobilised during sulphide weathering and enter the drainage network; precipitation of secondary oxidation minerals act as temporary stores for many heavy metals. The complexity of the mineral and heavy metal associations at Strauss Pit suggest that a detailed knowledge of these associations and distributions within ore bodies, and associated waste rocks, are needed by environmental managers of mine sites because the presence of havy metals may greatly affect the decision making process, and management strategies employed. Received; 14 July 1999 · Accepted: 17 August 1999     

江西德兴铜矿大坞河土壤重金属累积特征与成因

江西德兴铜矿是中国超大型斑岩铜矿,随着矿业活动的增加,德兴铜矿区重金属污染问题日益严重。查明德兴铜矿土壤重金属累积作用及原因,可为政府机构、矿山开展环境整冶提供科学依据。在大坞河上游、中游、下游选定3个剖面,采集50件土壤样品,得出其基于地球化学基线的累积特征。整体来讲,Cu、Mo累积作用最为显著,Cr、As累积作用明显,同时发现一级、二级阶地上累积显著,并从矿石组合、地化背景、河流阶地、元素形态、矿山生产等角度开展累积作用的原因分析。     

Distribution and fractionation of heavy metals in the surface sediments of the Ganges- Brahmaputra-Meghna river system in the Bengal basin

 The lower Ganges-Brahmaputra-Meghna (G-B-M) drainage basin occupies the total Bengal Basin, which is one of the unique basins of the world because of its location and size, density of population, and catastrophic deposition of sediments. The increased heavy metal concentration in the 63 m fraction of surface sediments shows similarity among major segments of the G-B-M system in the basin, which reflects the homogenization of lithologic and chemical diversity of the greater denudation regime by the river processes. The differences in heavy metal concentation in the lower G-B-M system with that of its upper and middle counterpart is mainly related to the contrast between Himalayan rivers and the other major South Asian rivers, and may be due to the geological differences of their denudation regime. Heavy metals in the Lower G-B-M system have an affinity towards the clay fraction of the sediments. The correlation matix of heavy metals in the lower Brahmaputra and Meghna suggests the importance of Fe-Mn oxyhydroxides in their accumulations. Iron, Ti and Mn are higher in the Meghna main channel, Zn is higher in the Meghna tributaries, and Cr is higher in both the Brahmaputra and Meghna compared to the value for standard shale. The enrichment factor is ≤1 for most of the metals except Mn which is relatively higher in the Meghna and lower Ganges main channels. The geoaccumulation index (I_geo) for most of the heavy metals lies below grade zero, suggesting unpolluted sediment quality. The lower Ganges system shows relatively higher concentration in the nondetrital fraction of heavy metals, probably due to the presence of petroleum refinery, industrial and mining effluents, and agricultural runoff in the drainage basin. The relative uniformity in concentration of heavy metals in vertical profiles may be due to the uniformity in sediment grain size and catastrophic deposition of sediments, where the time period represented by the vertical sediment column is not enough to reflect the cultural accumulation of heavy metals. The Bengal basin thus represents a relatively unperturbed alluvial basin with regards to heavy metal pollution. Received: 21 July 1997 · Accepted: 13 October 1997     

苏州河沉积物中Zn、Cu 、Hg的形态分布研究及沉积特点初探

本文以上海市苏州河沉积物为研究对象,采用Tessier形态分析法研究了沉积物中重金属元素Zn、Cu和Hg的含量变化与形态分布,初步探讨了沉积特点,对苏州河底泥的进一步治理提供了参考.结果表明,样品中Zn 、Cu、 Hg的含量匀接近或高于生物有影响水平;Zn 、Cu分别主要存在于有机态和Fe-Mn氧化物态中,可交换含量较少;Zn 、Cu、 Hg含量随沉积物浓度的变化为:沉积物表层重金属含量较低并略有起伏,中部较高,底层较低.