Seasonal variation and partition of trace metals (Fe, Zn, Cu, Mn, Cr, Cd and Pb) in surface sediments: relationship with physico-chemical variables of water from the Calabar River, South Eastern Nigeria

The seasonal variation and partition of trace metals (Fe, Cu, Zn, Mn, Cd, Cr and Pb) in the surface sediments of the Calabar River are reported. Chemical partition of the metals in the sediments reveals that 2–30% of the total metal load was contributed by the non-detrital (acid-soluble) fraction, while fine-grained host minerals/compounds are the main carriers of the detrital (acid-insoluble) fraction (70–98%). Using multivariate statistical analysis, the seasonal fluctuations in the distribution of some of the metals show significant influence by physio-chemical changes (dissolved oxygen, pH, salinity and conductivity) in the water column. Fe–Mn oxide grain coatings and sulphide materials have been identified as scavengers of some of the non-detrital and detrital trace metals in the sediments. On the basis of index of geoaccumulation (I-geo) and comparison with previous studies, the Calabar River surface sediments have been classified as unpolluted.     

Heavy metals in surface water and stream sediments in Jamaica

The levels of heavy metals in water and stream sediments in Jamaica are presented and compared to levels in soils and environmental standards. Heavy metals (cadmium, chromium, copper, mercury, nickel, lead and zinc) appear to be less of a problem to Jamaica's freshwater environment than might be expected given the concentrations in soils. This can be explained by taking into account the dynamics of the Jamaican water environment and the relative absence of anthropogenic sources. The dynamics of the freshwater system on the other hand, could pass any environmental threat to the coastal environment. Because the stream sediments are relatively coarse and contain little organic material the bio-availability of micropollutants such as heavy metals from the sediments can be expected to be relatively high.     

复合污染下Cu、Cr、Ni和Cd在水稻植株中的富集特征

掌握水稻对污染土壤中重金属的吸收和富集特征,为科学认识水稻中重金属的残留问题、健康风险提供理论依据。采用田间试验,研究了4个不同处理量Cu、Cr、Ni、Cd复合污染下水稻的富集特征及其随生育期的变化规律。结果表明,重金属在水稻植株各部位中吸收富集系数的大小依次为：Cd〉Cu〉Ni〉Cr,根部重金属吸收富集系数是地上各部位的吸收富集系数的2~100倍。各重金属在水稻植株不同部位的积累分布明显不同,成熟期水稻植株中Cu在水稻不同部位的质量分数为根〉茎≥叶〉米粒〉谷壳,Ni的分布规律为根〉叶〉茎〉米粒〉谷壳,Cr的分布规律为根〉叶〉谷壳≥茎〉米粒,Cd的分布规律为根〉茎〉叶〉米粒〉谷壳;且随着重金属处理量的增加,水稻植株不同部位的重金属质量分数也呈上升趋势。成熟期米粒中Cu、Ni、Cr和Cd的质量分数范围分别为：4.50~6.19、1.86~4.63、0.72~0.76和0.08~0.39 mg·kg-1,与无公害食品标准（GB15199-94、GBT2762-2005）相比,米粒中Cu和Cr的质量分数均未超标,而Ni和Cd（Cd高剂量处理时）的质量分数均超标,存在食用安全风险。重金属在水稻植株不同部位的质量分数随生育期均呈现先升后降的趋势,灌浆中期达到最大,而到成熟期又明显降低。不同重金属在水稻植株中的富集能力和分布规律均呈现明显差异,不同生育期水稻植株中重金属的质量分数明显不同但其质量分数变化呈明显规律性。     

Levels of heavy metals (Zn,Cu, Cd,and Pb) in mudskippers (Periophthalmodon schlosseri) and sediments collected from intertidal areas at Morib and Remis,Peninsular Malaysia

The concentrations of Zn, Cu, Cd, and Pb were determined in different tissues of mudskipper fishes Periophthalmodon schlosseri caught at two selected locations (Morib and Remis) of the intertidal mudflat area of Selangor state, West Coast of Peninsular Malaysia and in surface sediment samples. Metal concentrations in the mudskipper tissue and in the sediment samples tended to vary significantly (p < 0.05) between the two locations. Higher metal concentrations (except for Zn) were mostly found in the tissues of mudskippers from Remis. For sediment samples, significantly (p < 0.05) higher metal concentrations of all metals were also found at Remis. Generally, metal distribution between different tissues of mudskipper varied with scales being highly accumulative of Zn, Cd, and Pb, while for Cu, the highest mean concentrations were found in the liver. The lowest mean concentrations of Zn, Cu, and Cd were found in the muscles except for Pb, which was lowest in the liver. This study suggests that mudskippers can be potential biomonitoring organisms for heavy metal bioavailability and contamination of intertidal coastal mudflats. The concentrations of Cd and Pb were slightly above the acceptable limits of Malaysian and European food safety guidelines.     

成都市河流表层沉积物重金属污染及潜在生态风险评价

根据流经成都市内的三条河流（府河、南河、沙河）表层沉积物重金属数据，采用Hakanson潜在生态危害指数法对重金属的潜在生态风险进行了评价。结果表明（1）重金属潜在的生态危害因子（Er^i）说明大多属于轻微生态危害范畴，产牛生态危害的主要重金属是Hg、Cd，Cu、Pb次之，As影响最小；（2）多种重金属的生态系统的潜在生态风险指数（RI）表明河流重金属污染属于轻微生态危害和接近中等生态危害，其受危害程度由强至弱的次序为：府河，南河，沙河。     

The distribution of heavy metals in deposited urban dusts and sediments, Coventry, England

Samples of urban dusts and sediments have been collected and categorised into three compartment those which act mainly as sources, those undergoing transport and those which have been deposited. The sediments were fractionated into <63m to match similar sized lacustrine sediments and <2mm to represent natural and anthropogenic fluvially transported sediments. Preliminary results of total heavy metals analysis show that the <2mm fraction of the source group exhibits the greatest variabilty in metal concentrations. Overall, however, the <63m fraction dominates regardless of compartment. Some heavy metal concentrations decrease through the sourcetransportdeposit process, possibly due to selective onward transport of finer material or other anthropogenic processes unique to the urban environment (e.g. street cleansing). Sitespecificity is indicated in a comparison with other similar studies.     

Heavy metals contamination in mudflat and mangrove sediments (Mumbai,India)

The focus of this study, carried out on mudflat and mangrove sediments of Ulhas Estuary and Thane Creek in Mumbai, India, documents how sediment analysis in different ecosystems can help in understanding metal behaviour and pollution status of the region. Based on the the geoaccumulation index (I _geo ), the study shows that the estuarine and creek regions, being recipients of industrial and domestic wastes, display moderate pollution. Ulhas Estuary with higher clay and organic matter contents, exhibits higher amounts of metals than Thane Creek. Furthermore, using correlation and cluster analyses, the creek projects stable subenvironments with similar types of metal associations, with Fe and total organic carbon as the dominant metal carriers. By contrast, in the estuarine subenvironments, the metal associations do not reveal any distinct trend, which may be attributed to the disturbance caused by dredging activities routinely carried out in the region. Factor analysis carried out on I _geo data in both regions further helped in identifying polluted metal groups.     

The relationship between epilithic periphyton (biofilm) bound metals and metals bound to sediments in freshwater systems

Surficial sediments and epilithic periphyton (biofilm) were sampled from six sites on the River Churnet and five sites on the River Manifold in Staffordshire and analysed for cadmium (Cd), copper (Cu), lead (Pb) and zinc (Zn). The sites demonstrated a wide range of sediment trace metal concentrations determined by inductively coupled plasma optical emission spectrometry (ICP-OES) and atomic absorbtion spectroscopy (AAS). Biofilm was removed from the substrate using physical abrasion and 0.005 M ethylenediaminoethanetetra-acetic acid (EDTA) extractant. The European Standards, Measurements and Testing Programmes (BCR) operationally defined geochemical speciation scheme was used to determine the exchangeable, acid soluble fraction of the sediments. Significant positive correlations were determined between the EDTA extractable biofilm and the exchangeable sediment fraction for Cd, Cu and Zn but not for Pb. Natural epilithic periphyton may be a potential metal biomonitor particularly of Cu, Cd and Zn in aquatic systems and provide supporting information in relation to potential sediment toxicity.     

长江南京段近岸沉积物中重金属富集特征与形态分析

在对长江南京段八卦洲和杨中两个冲积洲近岸沉积物及其优势野生植物中A1、Cu、zn、Cr、Pb、Nj和Cd元素含量分析的基础上,分别考查了这些重金属的富集系数(EF)和生物富集因子(BCF),并采用BCR连续提取法对Cd的赋存形态进行了研究.结果表明,本区域长江近岸沉积物和野生植物中重金属存在不同程度的富集现象,两洲沉积物中Cu、Cr、Pb、Ni、Cd均有富集趋势,各元素EF>1的样品占总样品比例分别为Cu 50%、Cr40%、Pb40%、Ni 40%、Cd20%.而在野生桐蒿和芦蒿两种优势植物中Cd富集显著,其中桐蒿的BCF平均值高达2.57.采用BCR连续提取法对沉积物中Cd进行形态分析,结果显示,沉积物中Cd主要以酸溶/交换态(B1)和可还原态(B2)为主,二者分别为31.7%和45.5%,占到总量的70%以上,B1态远高于一般土壤和沉积物中重金属的分布,表现出很强的迁移性和生物可利用性.新生成沉积物较老沉积物中的B1态有显著增加,反映出沉积物越新,Cd的迁移性越强的趋势.研究结果说明长江城市段近岸沉积物中Cd受近期人为因素影响明显,具有一定的生态风险.     

Heavy metals in top core sediments from the southern Campania shelf (Italy): Hints to define large-scale geochemical backgrounds

The results of a geochemical survey carried out on the southern Campania shelf (southern Italy) are illustrated, offering a tempting opportunity to discuss the statement and definition of regional geochemical backgrounds for selected heavy metals. A total of 104 top core sediments, collected on average 1.5 km from one another and covering a shelf area of about 1300 km², were analysed for grain size, organic carbon content (OC), and heavy-metal (As, Al, Fe, Cd, V, Cr, Zn, Cu, Ni, Hg, and Pb) concentrations. The characteristics of the area, scarcely influenced by industrial activities, and the extensive data set, make this study suitable for an appropriate multivariate and spatial geostatistical methodologies used for i) a reliable definition of large-scale marine sediments' geochemical backgrounds and ii) an accurate discrimination of different geological controls on trace-element distribution patterns. Enrichment factors estimated with respect to both the average shale composition and the weighted average metal concentrations measured in inland soils rule out significant anthropogenic inputs. A spatial-geostatistics approach (kriging of spatial component based on an accurate implementation of variographic surveying) was applied, and this is proposed as an appropriate quantitative methodology to define the geochemical backgrounds for the different heavy metals. Two nested spatial structures were identified for some of the heavy metals, thus allowing clear identification of local and regional geochemical controls related to the different spatial variability of grain size.     

Fractionation of Mn, Fe, Zn and Cu in Sediments of Khor Kalabsha, Lake Nasser, Egypt

Khor Kalabsha is the second largest Khor in Lake Nasser, which is a freshwater side-branch of the main lake. Chemical analysis of the samples indicates that calcium carbonate and organic matter content in the surface sediments average 17.8 and 3.07%, respectively. Moreover, manganese, iron, zinc and copper concentrations are lower in Khor Kalabsha than in other lakes of Egypt. It has been found that both oxides and residual forms constitute the major part of the measured elements in the study area, while manganese and iron play an important role in building up clay minerals. It is noted that both zinc and copper fractions are controlled by biological and biochemical processes.     

Impact of nickel mining and metallurgical activities on the distribution of heavy metals in sediments of Levisa, Cabonico and Nipe Bays, Cuba

At MayarÕ zone, northeast Cuba, important lateritic deposits have been exploited since 1943. The mineral is used as raw material in a nickel-processing plant which discharges its untreated solid and liquid wastes into Levisa Bay. Similarly to the adjacent Nipe and Cabonico bays, fluvial currents from the mining areas convey a significant mineral load into this bay. To assess the environmental impact caused by the mining and the metallurgical activities, the distribution of Ni, Co, Fe, Mn, Cu, Pb and Zn was investigated in surface and core sediment samples. Uni- and multivariate statistical methods as well as different indices and pollutant factors were used to interpret results. These revealed significant environmental impacts in some areas of the three bays with high concentrations of Ni, Co, Fe and Mn, whose values are up to two orders of magnitude greater than the zone baseline levels. The metal concentrations decreased with increasing distance from discharges. A comparison with other Cuban bays and coastal zones, confirmed that the main source of metal pollution in these three bays was not urban and industrial activities, but lateritic mining and metallurgy.     

深圳蛇口渔港沉积物重金属分布及潜在生态风险评价

沉积物重金属污染对水生生态系统具有潜在危害.渔港是海岸带水环境的重要组成部分.对取自深圳蛇口渔港的10个表层沉积物样品中的As、Cd、Cu、Pb和Zn等典型重金属元素进行了分析,探讨了其空间分布;运用地积累指数法(Igeo)和生态危害指数法(RI),评价了表层沉积物中重金属的富集程度和潜在生态风险,初步探讨了其污染来源.结果表明:(1)蛇口渔港海域沉积物重金属Cu的污染十分严重,Zn和Pb污染较严重,其浓度均为港内>港口>港外;(2)渔港内沉积物重金属的富集达重度污染程度,潜在生态危害风险强.其中,又以Cu的富集程度最高,潜在生态危害风险最强;(3)渔港内Cu的污染,可能与电子工业废水的排放,以及渔业特有的防附着生物涂料有关.     

Heavy metals associated with reduced sulfur in sediments from different deposition environments in the Pearl River estuary, China

Distribution of acid volatile sulfur (AVS) and the simultaneously extracted metals (SEM: Cu, Pb, Zn, Cd, Ni) in sediment profiles has been studied at five sites in Pearl River estuary, China. Of the five sampling locations, Nos.1 and 2 are in the middle shoal, Nos.3 and 4 in the west shoal and No. 5 locates to the south of the estuary. The AVS content in the sediments of the middle shoal varies in a small range (0.25–4.06 μmol g⁻¹), while that of west shoal increases with depth from 0 to ultimately 26.09 μmol g⁻¹. The SEM concentration in the sediment profiles at location Nos. 1, 2 and 5 is generally in the range of 0.95±0.2 μmol g⁻¹ with a slight upward increase, while that in the sediment of west shallows are much higher (1.43–2.42 μmol g⁻¹) with a significant upward increase, especially in the upper layer of ca. 15 cm. The observed upward increase of SEM content at all the sites implies that heavy metal contamination of sediment in the Pearl River estuary is increasing. Calculations of the excess heavy metal content which is defined by SEM-AVS molar difference suggests that the upper sediment in the Pearl River estuary, especially on the west shallows, could be a source of heavy metal contaminants and may cause toxicity to the benthos. The site-specific distribution patterns in the AVS and SEM profiles were interpreted according to the hydrogeochemistry of deposition environments.     

Heavy Metals in Sediments and Oysters From Bluefields Bay, Nicaragua

The distribution of trace metals (Co, Cu, Fe, Mn, Ni, Pb and Zn) was investigated during a year (1994-95) in surface and core sediment samples and in the oyster (Crassotrea rhizophorae) from Bluefields Bay, Nicaragua. the aim was to assess the arthropogenic impact of potential pollutant sources, mainly Bluefields City, since domestic waste waters are discharged directly or by infiltration to the bay. Lyophilised samples were submitted to different acid digestion methods and analysed by flame atomic absorption spectrophotometry. the results showed highest contents for copper, lead and zinc near Bluefields City, with an increase in the affected area in the rainy season that is generated by greater city run off. Metal contents in oysters do not show the same distribution pattern than in sediments and were similar to those from other areas without reflecting pollution levels.     

镇江市古运河河岸沉积物重金属分布特征及潜在生态风险评价

对镇江市古运河河岸7个表层沉积物中重金属As、Cu、Pb、Cd、Zn、Cr含量进行测定,并通过富集系数、地累积指数法、潜在生态风险评价以及主成分分析等对沉积物重金属的分布特征进行综合分析与评价.结果表明:(1)古运河河岸带沉积物Cr、Cu、Zn、As、Pb和Cd元素的含量平均值分别为45.07、41.70、254.06、19.67、45.88、0.75 mg·kg-1,p H平均值为7.98.对比《国家土壤环境质量标准》可知,沉积物中Cu、Zn、Pb、As属于超一级标准,而Cd属于超二级标准.(2)6种重金属的富集系数表现为:AsCdPbZnCuCr,且综合富集系数在空间上表现为:G2G5G1G4G3G7G6;(3)古运河河岸表层沉积物地累积指数表现为AsCdPbCuZnCr,6种重金属中As富集量最大,Cr的富集量最小.(4)单项潜在生态危害系数结果表明,Cr、Cu、Zn、Pb均为轻微生态危害程度,As和Cd处于中等生态危害程度.从RI值判断,古运河河岸沉积物总体处于轻微生态危害.(5)相关性和主成分分析结果表明,Pb、Cu、Cr、Cd是决定第一主成分的4个主要因子,且Cu与Pb、Cd以及Pb与Cd元素具有相同的污染源.As、Zn在第二主成分中具有较高的载荷值,且As与Zn之间的相关性较弱,表明这两种重金属并非来自同一污染源.     

珠海近岸海域表层沉积物中的重金属及生态危害评价

为了研究珠江口近海海域重金属的污染状况,2009年8—12月对珠海珠江口4个站点的表层沉积物进行了6次采样,测定了表层沉积物中重金属Cd、Cr、Pb、Hg、Cu、Zn、Mn、Ni、Fe和金属Al的质量分数,分析了它们质量分数间的相关性,依据Lars Hakanson提出的沉积物中金属污染物评价方法,对Cd、Cr、Pb、Hg、Cu和Zn等6种典型重金属的潜在危害进行了评价。结果表明,Cd、Cu和Zn是该调查区域的主要重金属污染物,应该予以优先控制和治理。位于马骝洲水道入海口的S1位点上,金属元素（Cd除外）质量分数的季节特征是秋季（丰水期）〈冬季（枯水期）,重金属危害指数（RT）为轻微级,重金属潜在生态危害系数（Eir）顺序为Cd〉Hg〉Pb〉Cu〉Zn〉Cr;在S2位点,Cd、Cu、Hg、Ni和Fe的平均质量分数为秋季〉冬季,其它5种金属则为秋季〈冬季,RT为强级;在S3、S4位点上,8种金属元素（Hg、Mn除外）的质量分数呈现秋季〉冬季的现象,RT为很强级;S2、S3和S4站点的Eir均表现为Cd〉Hg〉Cu〉Pb〉Zn〉Cr的顺序。     

Effect of mixtures of metals on the spotted Babylon snail (Babylonia areolata) under different temperature conditions

A study was conducted on the Babylon snail (Babylonia areolata) to examine the effects of copper (Cu), cadmium (Cd), nickel (Ni), and zinc (Zn) on different life stages of this gastropod. Metal toxicity significantly varied according to the life stage of the snail. The different LC₅₀ values obtained were 0.51, 5.49, 0.31, and 0.2 ppm for Cu, Zn, Cd, and Ni for the larval stage and 4.98, 15.19, 0.91, and 1.21 ppm at the juvenile stage and 8.54, 17.52, 1.14, and 1.44 ppm in the adult stage. Studies were also conducted on the effects of dual metal concentrations and experiments were repeated with temperature as a variable. Results demonstrated that metal toxicity values were altered depending on the metals involved in the combination as well as temperature under which the experiment was conducted.     

AVS-SEM relationships and potential bioavailability of trace metals in sediments from the Southeastern Mediterranean sea,Egypt

In risk assessment of aquatic sediments, much attention is paid to the difference between acid volatile sulfide (AVS) and simultaneously extracted metals (SEM) as indicators of metal bioavailability. Distribution of AVS and SEM (Cd, Cu, Ni, Pb and Zn) were determined in 20 representative sampling sites collected along the Egyptian Mediterranean coast. Total SEM concentration [ΣSEM] ranged from 0.012 to 0.241 μmoleg^?1. AVS concentrations were much more variable, showing significant spatial variations. The values ranged from 0.015 to 31.326 μmoleg^?1. The different relationships between AVS and SEM to establish mechanical models such as the ratio of ΣSEM and AVS [ΣSEM/AVS], the difference between the ΣSEM and AVS [ΣSEM–AVS], or the organic carbon normalised difference between SEM and AVS [ΣSEM-AVS]/f_oc models were used as parameters to evaluate potential bioavailability. Considering SEM/AVS model, sediments at the Western Harbour, Eastern Harbour, Ras El-Burr, El-Gamil East, and Port Said stations are occasionally toxic, while according to SEM-AVS model, no indication of associated adverse toxic effect would occur at any of the sampling sites. Calculated [ΣSEM-AVS]/f_oc was<130 μmoleg^?1 in the sediments indicating that sediments should pose a low risk of adverse biological effects owing to cadmium, copper, lead, nickel and zinc. Association of adverse effects to aquatic organisms was determined, using the classification of the sediments according to the Sediment Quality Guidelines (SQGs). The marine Threshold Effect Levels (TEL) and Probable Effect Levels (PEL) were used in this work and in order to obtain a more realistic measure of predicted toxicity, mean PEL quotients (PELq) were calculated. The mean PELq calculated for the sampling sites was (0.11–1.5) and categorised as slightly toxic at all stations except Baghoush, Nobarreya and western harbour, which had PELq<0.1 and categorised as non-toxic. The obtained data concluded that the remobility and bioavailability of trace metals contained in surfacial sediments of the Egyptian Mediterranean coastal area are low.     

Heavy Metals and Arsenic in Sediments, Mussels and Marine Water from Murano (Venice, Italy)

This paper describes a study of the trace element distribution in sediments, marine water and mussel Mytilus galloprovincialis of the Venetian Lagoon around the Island of Murano, an island with a long tradition of glassmaking. Trace elements analysed include Fe, Mn, Zn, Cu, Cr, Pb, Ni, Ag and As. Sediments are contaminated with Zn, Cu, Ag, As and Pb, with levels in the <2m fraction that are likely to cause adverse biological effects to marine organisms. The pelite (<63m) is the main carrier of heavy metals at most sites. However, the fine-grained and coarse sand on the southern coast of Murano accounts for a significant proportion of Fe, Mn, Zn, Cr, Ag, Ni and Pb. Most trace element concentrations found in soft tissue of mussels appear to be within recommended Italian and international guidelines for shellfish for human consumption, the only exception being relatively high As levels. The bioaccumulation of Ag and Cr is more pronounced in the shell of these organisms. In the marine water of the lagoon, trace elements are more enriched than in other areas of the Mediterranean, with particular reference to the dissolved labile species of Zn, Mn, As, Cu, Ni and Cr.