A study of trace element contamination in river sediments in Serbia using microwave-assisted aqua regia digestion and multivariate statistical analysis

The aim of this study was the evaluation of the trace element contamination level in sediments of the most important rivers in Serbia and their tributaries. The determination of the aqua regia soluble contents of 12 micro- and macro-elements (Ca, Cd, Co, Cr, Cu, Fe, Mn, Pb, Ni, Zn, Be and V) in sediments was developed by the microwave digestion technique combined with inductively coupled plasma atomic emission spectrometry. Correlation analysis and principal component analysis distinguishes factors of lithogenic and anthropogenic origins. The Fe, Mn, Be and V contents are controlled by a regional lithogenic high background factor, while Cd, Cr, Pb, Ni, Zn and Cu are recognized as tracer of pollution. For Co, mixed sources from both lithogenic and anthropogenic inputs were evidenced.The investigated sediment of the major rivers and their tributaries in Serbia showed high concentrations of metals, especially of Cd, Pb, Cu and Zn, which may cause serious environmental impacts. Rivers which flow into the Danube from its entrance into Serbia significantly influence the chemical load of the water and sediments.The experimental study was conducted using two BCR standard reference materials. The calculated accuracy and precision confirmed the good performance of the adopted procedures.     

Characterization of Metals in Surface Sediments from Xiaoyang River,Jiangsu, China

Some metal species and fractions have high affinity to anthropogenic activities, making it feasible to characterize the spatiotemporal characteristics of human-induced degradation of ecosystems. The accumulation of Fe, Mg, Mn, Zn, Cu, Cr, Ni, and Pb, their fractions, physiochemical parameters, and nutrients was evaluated in the surface sediments at 11 sites on the Xiaoyang River in urban and suburban locations in Jiangsu, China for the assessment of pollution. The sediment quality was evaluated based on sediment quality guidelines, enrichment factors, geoaccumulation index, potential ecological risk index, and risk assessment code. Principal component analysis and cluster analysis were used to identify the sources of the metals. The total concentrations of metals, enrichment factors, and geoaccumulation indices demonstrated that all sites were significantly polluted with Zn and significantly to moderately polluted by Cu, Pb, and Ni. Moreover, higher metal enrichment was present downstream through downtown Sheyang due to extensive human activities. However, the potential ecological risk indices and risk assessment codes revealed high bioavailability and toxicity of Pb in this region. These results indicated that the metal fraction showed higher susceptibility. The accuracy of the ecological risk assessment was evaluated in the river, indicating a heavy anthropogenic impact.     

Assessing spatial distribution,sources, and potential ecological risk of heavy metals in surface sediments of the Nansi Lake,Eastern China

The study is conducted to investigate the spatial distribution, sources and ecological risk of seven heavy metals in surface sediments of Nansi Lake, Eastern China. A total of 29 samples were collected in surface sediments of Nansi Lake, and were analyzed for three nutrients (TN, TOC and TP), two major metals (Al and Fe), as well as seven trace metals (As, Cd, Cr, Cu, Hg, Pb and Zn). The mean concentrations of As, Cd, Cr, Cu, Hg, Pb, Zn, Fe and Al were 14.41, 0.22, 71.10, 30.1, 0.048, 29.14, 90.2, 30,816 and 70,653 mg kg^?1, respectively, and the mean contents of these metals were higher than the background values with the exception of Cu and Fe. The spatial distribution indicated that the contents of all seven heavy metals were characterized by relatively higher contents in the upper lake than the lower lake. The hotspots with high values of As, Cd and Hg were associated with the river mouths, and the hotspots of Pb were mainly located around the dam in the central part, while no significant associations were displayed between spatial distribution of Cr, Cu, Zn and the river mouths. The mean enrichment factor (EF) values of As, Cd, Hg and Pb were 2.03, 2.93, 3.21 and 2.18, respectively, showing their moderate enrichment, while Cr, Cu and Zn with mean EF values of 1.19, 0.89 and 1.01 were deficiency to minimal enrichment. Multivariate and geostatistical analyses suggested that PC1 controlled by Cr, Cu and Zn was a lithogenic component, and come from parent rocks leaching. PC2 including Cd and partially Hg represented the factor from industrial wastewater discharge. PC3 showed elevated loadings of As and partially Cd, and could be attributed to the agricultural practices. While PC4 including Pb and partially Hg, was dominated by coal combustion. The results of potential ecological risk suggested that sediment environment of Nansi Lake suffered from high ecological risk.     

Assessment of trace metals contamination in estuarine sediments using a sequential extraction technique and principal component analysis

Fractionation of the metals Cd, Cr, Cu, Ni, Pb and Zn in sediments was performed for samples collected from eight locations in the Poxim river estuary of Sergipe State, northeast Brazil, using the 3-stage sequential extraction procedure proposed by the European Community Bureau of Reference (BCR). The extraction method was found to be satisfactory for analysis of certified reference material BCR-701, with recovery values ranging from 85% (Cu) to 117% (Cr). The detection limits obtained were 0.001 to 0.305 µg g^− 1. Zn exhibited greatest mobility and bioavailability, indicative of anthropogenic sources, while Cr was mainly found in the residual fraction and could be used as an indicator for the contribution from natural sources. Cd, Cu, Ni and Pb were associated with the oxidizable fraction, and Pb, Cr and Ni with the reducible fraction. Principal component analysis (PCA) clearly separated the metals into three groups: I (Zn); II (Pb); III (Cd, Cu, Cr and Ni). These groupings were mainly due to different distributions of the metals in the various fractions, in sediments from the different locations. Risk assessment code (RAC) analysis indicated that although the metals presented a moderate overall risk to the aquatic environment, nickel showed a low risk (RAC < 10%) at three sites, while zinc presented a high risk (RAC > 30%) at four other sites.     

Contamination assessment of heavy metal in surface sediments of the Wuding River, northern China

The heavy metal contents and the contamination levels of the surface sediments of the Wuding River, northern China, were investigated. Heavy metal concentration ranged in μg g⁻¹: 50.15–71.91 for Cr, 408.1–442.9 for Mn, 20.11–43.59 for Ni, 17.51–20.1 for Cu, 68.32–89.57 for Zn, 0.2–0.38 for Cd and 15.08–16.14 for Pb in the Wuding River sediments. The enrichment factor (EF) and the geo-accumulation index (Igeo) demonstrated that the sediments of the Wuding River had been polluted by Cd, Cr and Ni, which mainly originated from anthropogenic sources, whereas the sediments had not been polluted by Zn, Pb, Cu and Mn, which were derived from the crust. In addition, the assessment results of EF and Igeo suggested that the sediments of the Wuding River was “moderately” polluted by Cd and “unpolluted to moderately” polluted by Cr and Ni. The elevated urban sewage discharges and agriculture fertilizers usage in river basin are the anthropogenic sources of these heavy metals in river.     

Exposure assessment of heavy metals in water and sediments from a Western Mediterranean basin (Rio Guadalhorce,Region of Andalusia,Southern Spain)

Concentrations of heavy metals (Cd, Cr, Cu, Ni and Pb) were measured in sediment and water from a representative Western Mediterranean basin in South Spain: Guadalhorce River. In the later twentieth century, cities such as Málaga (capital of the Costa del Sol), have suffered the impact of the mass summer tourism. The ancient industrial activities, abandoned mine sites and the actual urbanisation and coastal development, recreation and tourism, wastewater treatment facilities, have been sources of pollution. This river has been heavily modified, with three dams for volume regulation purposes owing to the climatic cycles, with some years very dry and others with torrential rains. In this study, different indices to assessment of sediment contamination, statistical tools (Kruskall–Wallis test, Conglomerate analysis), sequential extraction methods and environmental quality guidelines have been employed to assess the possible contamination of this basin. Other physical–chemical parameters as chloride concentration, pH and conductivity were also measured. The results indicated that Ni and Cu were the most troublesome metals because they were more easily mobilisable than Cr and Pb; Ni exceeds the SQGs guidelines, and Cu presents considerable contamination. These metals were derived from lithogenic and anthropogenic sources, respectively, according to the enrichment factors (EF) values. Ni was the most dangerous because Ni concentrations exceeded the threshold effect concentration (TEC) below which harmful effects are unlikely to be observed, in 96.6% of the samples analysed and even the probable effect concentration (PEC) above which harmful effects are likely to be observed, in 56.6%. The cause of this pollution was postulated to be by abandoned Ni mines, which indicates that the pollution from mining persists during several decades. Multivariate analyses used in this study provide important tools for better understanding of the pollution source identification.     

Elemental Analysis of Edible Mountain Nettle (Obetia tenax) and the Influence of Soil on Its Chemical Composition

In developing countries, the dietary intake of essential elements is largely dependent on the consumption of edible fruits and leafy vegetables. The distribution of elements in the indigenous edible plant, Obetia tenax (mountain nettle), was investigated as a function of soil quality from eight sites in KwaZulu-Natal, South Africa. The results show concentrations of elements in the leaves to be in decreasing order of Ca?>?Mg?>?Fe?>?Mn?>?Zn?>?Cr?>?Cu?>?Ni?>?Pb?>?Co?>?As?>?Cd?>?Se, and in the stems and roots to be in decreasing order of Ca?>?Mg?>?Fe?>?Mn?>?Zn?>?Cu?>?Ni?>?As?>?Pb?>?Co?>?Cd?>?Cr?>?Se. The quality and pollution status of soil was evaluated by geoaccumulation indices and enrichment factors, which indicated moderate cadmium contamination at the Msinga location that was confirmed by the pollution index and ecological risk levels of single-factor pollution. An assessment of overall contamination of soil using Nemerow pollution index showed moderate pollution by cadmium, while the potential toxicity index indicated low-grade risk for all elements at all sites. Principal component and cluster analysis revealed two groups of elements with similarities, As, Cd, Co, Cr, Cu, Mn, Ni, and Fe, suggesting a lithogenic source and an anthropogenic source for Pb and Zn. Correlation analysis showed significantly positive correlations between As, Co, Cr, Cu, Fe, and Ni/Cd in the soil, confirming the elements’ common origin.     

煎煮对几种特色南药中重金属元素含量和形态影响

考察了几种特色南药中重金属(Cd,Cr,Cu,Fe,Mn,Ni,Pb,Sr,Zn)的含量状况,并采用形态连续萃取法分析重金属在药材中的形态分布,研究了药材煎煮时药材中重金属的释放及煎煮过程对药材中重金属形态分布的影响。结果表明,几种南药中Cr,Pb,Zn的含量较高,且巴戟天中的重金属总量高于限量标准;原药材中Cr,Cu,Mn,Ni,Pb和Zn主要存在于有机态和残留态,Fe和Sr主要存在于残留态。煎煮使南药中大量重金属迁移到药汤中;药汤中Cu,Mn,Cr,Pb和Zn主要来自于其在药材中的可交换态、碳酸盐结合态和有机态,而药汤中Sr,Ni和Fe不仅包含其非残留态,更多来自于它们的残留态。为减少药汤中重金属,对于Cu,Mn,Cr,Pb和Zn既要控制在药材中的总量,且需降低它们在药材中的非残留态含量;对于Fe,Ni和Sr则主要是控制其在药材中的总量。     

耐高盐碱蓬对湿地土壤中金属元素的富集特征研究

基于秦皇岛滨海湿地人工种植耐高盐碱蓬修复工程试验,通过分析湿地土壤沉积物及耐高盐碱蓬中不同金属元素的含量与变化,研究了耐高盐碱蓬对金属元素的富集特征。结果显示:湿地沉积物中Fe、Mn、Cr、Pb和Zn的浓度较高,分别为8 210. 94、110. 04、8. 78、8. 25、10. 95 mg/kg,Cd的浓度最低,平均值为0. 022 mg/kg,湿地试验区土壤中同一金属元素变异程度较小,分布较均匀。碱蓬体内重金属含量根据采集地点的不同有差异,但与各站位中土壤的重金属分布特征存在正相关性;其中碱蓬内Fe、Mn、Zn、Cu的平均含量相对较高,且Fe、Mn、Ni、Cu、As、Cd、Pb元素在碱蓬根中的平均含量高于茎叶,而Cr在茎中的平均含量最高,Zn和Mo在叶中的含量最高。碱蓬的根、茎、叶对Cd的富集效果最好,其次为Mo、Cu,对Fe、Mn、Zn、As和Pb的富集效果相对较差,说明碱蓬对沉积物中不同金属元素的富集移出率存在差异。金属元素在碱蓬中的转移系数研究表明,Mo、Zn、Cd和Mn等元素可由根部转移到叶中,而Fe、Ni、Pb、As和Cu等金属元素固定在根部,该研究可为利用碱蓬修复湿地重金属污染提供理论基础。     

Comparison of metal analysis in sediments using EDXRF and ICP-OES with the HCl and Tessie extraction methods

The work presents an investigation on metal availability in sediments during 13 months using the dispersive-energy X-ray fluorescence (EDXRF) and atomic emission spectrometry with induced argon plasma (ICP-OES) techniques and single extraction (0.1 mol l⁻¹ HCl) and Tessie’s sequential speciation methods. The EDXRF technique could yield essentially the same profile as ICP-OES for the seasonal variation of metals in sediments, but in a more practical way. The sequential extraction procedure (SEP) was more efficient in metal dissolution than single extraction. The Pb, Ni, Al, Cr, and Fe elements were less efficiently extracted with single extraction in relation to sequential extraction. For Co both methodologies were equivalent, but for Cu and Mn the extraction was higher with single extraction. Single extraction does not mobilize Pb, Ni, Al, Cr, and Fe adsorbed on oxides and bound to organic matter. However for Cu and Mn, not only extracted these metals from the four fractions, but it also dissolved part of the fifth fraction (residual). Principal Component Analysis discriminated seasonal variations in the content of several metals, mainly Fe, Co, Ni, and Zn. The mobility of metallic ions in the sediments is conditioned to the seasonal flow of organic and inorganic material coming from the river or by the erosion of adjacent soils.     

氧化与还原条件下伊通河长春区段沉积物重金属形态特征的对比研究

利用改进的Tessier连续萃取法研究了伊通河长春市自由大桥处不同深度沉积物样品在氧化及还原条件下Cu,Pb,Zn和Ni的形态变化规律,同时分析了沉积物样品中酸可挥发性硫(Acid volatile sulfide,AVS)和同时提取重金属(Simultaneous extract metals,SEM)的含量. 实验结果表明，样品经干燥、研磨处理后,Cu有机/硫化物结合态比例减少40%,锰氧化物结合态的比例显著增加; Pb,Zn和Ni 3种元素有机/硫化物结合态比例均略有下降,变化幅度小于Cu,并重新分配到不同的化学相中. 通过SEM中各金属含量与有机/硫化物结合态中金属含量的对比可知,还原性沉积物中Cu除了与硫化物结合外,很大一部分是以有机物形态存在的,Pb,Zn,Ni,Fe和Mn则主要以硫化物形态存在,各元素形态分析均不同程度地受到萃取剂的影响.     

A review of heavy metal contaminations in urban soils, urban road dusts and agricultural soils from China

This paper reviews quite a few heavy metal contamination related studies in several cities from China over the past 10 years. The concentrations, sources, contamination levels, sample collection and analytical tools of heavy metals in urban soils, urban road dusts and agricultural soils were widely compared and discussed in this study. The results indicate that nearly all the concentrations of Cr, Ni, Cu, Pb, Zn, As, Hg and Cd are higher than their background values of soil in China. Among the cities, the contamination levels of the heavy metals vary in a large range. The geoaccumulation index shows that the contamination of Cr, Ni, Cu, Pb, Zn and Cd is widespread in urban soils and urban road dusts of the cities. Generally, the contamination levels of Cu, Pb, Zn and Cd are higher than that of Ni and Cr. Agricultural soils are also significantly influenced by Cd, Hg and Pb derived from anthropogenic activities. The integrated pollution index (IPI) indicates that the urban soils and urban road dusts of the developed cities and the industrial cities have higher contamination levels of the heavy metals. The comparison of the IPIs of heavy metals in urban soils and urban road dusts of Shanghai, Hangzhou, Guangzhou and Hongkong reveals that the contamination levels of the metals in urban road dusts are higher than that in urban soils in the cities. Moreover, the main sources of the metals in urban soils, urban road dusts and agricultural soils are also different.     

Uptake,Translocation, and Bioaccumulation of Elements in Forest Nettle (Laportea alatipes)

Elements found in the edible parts of plants are considered to be the main source of nutrients for humans and animals. However, there is insufficient information on the relationship between heavy metal pollution in the growing soil of most edible plants. In this study, the distribution of elements in the edible forest nettle (Laportea alatipes) was evaluated as a function of geographical location. Forest land soils had higher concentrations of minor elements (Cu, Cr, Ni, and Zn) compared to soils from rural and suburban areas. Translocation factors for Cd and Pb showed effective translocation from the roots to the leaves; however, these heavy metals in leaves were still above South African maximum permissible levels for vegetables. Atmospheric depositions may play a significant role in higher Cd and Pb concentrations in the leaves. Bioaccumulation factors showed the plant to accumulate Cu, Mn, and Zn to meet physiological requirement levels. Geoaccumulation indices and enrichment factors showed no soil contamination or minimal enrichment by trace metals. Principal component analysis showed Co, Cr, Cu, Fe, Ni, Pb, and Zn in soil to originate from a common source which may be soil silicates and other minerals.     

Distribution and speciation of metals in surface sediments of Taranto [corrected] gulf (Ionian Sea, Southern Italy)

Concentrations of metals (Al, Fe, Ti, Ni, Mn, Cr, Zn, Cu, Pb) were determined in surface sediments from Taranto gulf (Ionian Sea, Southern Italy) in order to assess the distribution and the bioavailability of metals. Total metal content and speciation of Fe, Ni, Mn, Zn, Cu and Pb were determined. Sediment cores were also sampled in some stations of particular interest. The analytical results show that metals distribution does not show significant variations in relation to depth. Metal distribution in the Taranto gulf is mainly influenced by industrial wastes from Taranto town, by rivers of the Basilicata region and by prevailing anticlockwise marine currents. These factors cause an accumulation of metals in the sediments near to the coasts of Calabria. The statistical analysis, effected by HCA and PCA methods, can be considered a good starting point in order to classify sediment samples and to locate accumulation areas. Metal speciation shows that Fe, Ni and Zn are present in sediments mainly as sulphides, Mn is present principally in an ion-exchange form or bound to carbonate, while Cu and Pb are mainly present in the fraction bounds to humic acids.     

Metals in water and surface sediments from Henan reaches of the Yellow River, China

The concentrations of Cd, Cr, Cu, Ni, Pb and Zn were determined in the water and surface sediments from the Henan reaches of the Yellow River. Twenty-three sampling sites along the Yellow River and its tributaries were selected. Generally, metal concentrations were found to decrease in sequences of Zn > Cu > Pb > Cr > Ni > Cd in water and Zn > Cr > Pb > Ni > Cu > Cd in sediments. High levels of metal concentration were determined at a few stations of the river and its tributaries, such as Yiluo River, Si River and Qin River. The pollution of the Yellow River by Cd, Cr, Cu, Ni, Pb and Zn can be regarded as much higher compared to the background values, US EPA criteria (1999) and China water quality criteria (2002). For sediments, metal levels except Pb did not significantly exceed the average shale levels and backgrounds in several countries including China. Data analysis manifests that positive correlations were found between Cu, Ni and Zn in water, and Pb, Ni, Zn and Cr in sediments. The Pearson correlation coefficient analysis and Cluster analysis were provided to assess the possible contamination sources. The results indicate a general appearance of serious pollution along the banks of the Yellow River. The wastewaters discharged by the mine plants, smelter plants, power plants, battery plants, tannery plants, etc., and sewage inputs from the cities along the river banks may be the sources of metals.     

A comparison of an optimised sequential extraction procedure and dilute acid leaching of elements in anoxic sediments, including the effects of oxidation on sediment metal partitioning

The effect of oxidation of anoxic sediment upon the extraction of 13 elements (Cd, Sn, Sb, Pb, Al, Cr, Mn, Fe, Co, Ni, Cu, Zn, As) using the optimised Community Bureau of Reference of the European Commission (BCR) sequential extraction procedure and a dilute acid partial extraction procedure (4 h, 1 mol L⁻¹ HCl) was investigated. Elements commonly associated with the sulfidic phase, Cd, Cu, Pb, Zn and Fe exhibited the most significant changes under the BCR sequential extraction procedure. Cd, Cu, Zn, and to a lesser extent Pb, were redistributed into the weak acid extractable fraction upon oxidation of the anoxic sediment and Fe was redistributed into the reducible fraction as expected, but an increase was also observed in the residual Fe. For the HCl partial extraction, sediments with moderate acid volatile sulfide (AVS) levels (1-100 μmol g⁻¹) showed no significant difference in element partitioning following oxidation, whilst sediments containing high AVS levels (>100 μmol g⁻¹) were significantly different with elevated concentrations of Cu and Sn noted in the partial extract following oxidation of the sediment. Comparison of the labile metals released using the BCR sequential extraction procedure (ΣSteps 1-3) to labile metals extracted using the dilute HCl partial extraction showed that no method was consistently more aggressive than the other, with the HCl partial extraction extracting more Sn and Sb from the anoxic sediment than the BCR procedure, whilst the BCR procedure extracted more Cr, Co, Cu and As than the HCl extraction.     

Distribution of Minor and Trace Metals in Carezza Lake (ANTARCTICA) Ecosystem

Abstract

This paper reports the distribution of a series of metals in natural samples collected at Carezza Lake in Antarctica, during the Italian Expedition in the austral summer 1989/90. The considered elements are: water, sediments and soil sampled from the surroundings of the lake and algae. The determination of the total concentration of the following metals was performed: Al, As, Ca, Cd, Co, Cr, Cu, Fe, Mg, Mn, Na, Ni, Pb, Zn. In addition, for sediment and soil samples, a speciation study was performed for some metals, namely Cd, Co, Cr, Cu, Fe, Mn, Ni, Zn, using the Tessier procedure.     

Geochemical characterisation of Antarctic soils and lacustrine sediments from Terra Nova Bay

In Terra Nova Bay region (northern Victoria Land, Antarctica), the interactions among soil, meltwater and lakes are poorly understood with regard to the physicochemical transformations that occur when solid materials are exchanged among them. In order to ascertain the natural dynamics of several elements, namely Al, As, Ca, Cd, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, P, Pb, Ti and Zn, as well as the perturbations by human activities and/or global contamination, soils and sediments from four catchments (Tarn Flat, Edmonson Point, Inexpressible Island and Northern Foothills) were studied.To accomplish the above mentioned objectives, the particle-size distribution and mineralogical composition, as well as the total C, H and N contents and the total concentrations of the investigated elements were determined. Finally in order to assess metal mobility, the modified BCR three-step sequential extraction procedure was applied to the samples and the partitioning of five metals, namely Cr, Fe, Mn, Pb and Zn, into different fractions was determined.Lithology and topography are the main factors that differentiate the physicochemical characteristics of the soils and sediments investigated. The lacustrine sediments and the soils sampled around the lakes showed a similar mineralogical and chemical composition, as evidence that rock- and soil-weathering processes occur primarily during the warm summer periods, when the lakes are partially ice-free. Nevertheless the presence of chlorite in these systems indicated that chemical weathering has taken place even in these extreme conditions. In general, the geochemical composition of soils and sediments in this Antarctic area seems to be influenced mainly by the nature of the bedrock and by the input of sea-spray, and, to a lesser degree, by mechanical and chemical weathering as well as by biological processes; no evidence of a local or global anthropogenic contamination was found.     

铅接触者铅与锰、铬、镍、镉、铜、铁、锌、钙、镁相关关系的分析

检测了50名名接触者在驱铅前后全血中铅、锰、铬、镍、镉水平以及血清中铜、铁、锌、钙、镁水平,并将其与50名对照组比较。结果表明,铅对人体内钙、镁、锌、铜、铬、镍均有影响。