Distribution,bioavailability, and potential risk assessment of the metals in tributary sediments of Three Gorges Reservoir: The impact of water impoundment

To investigate the impact of water impoundment on the metal contamination in sediments cores from the three tributaries of Three Gorges Reservoir (TGR), the concentrations, distribution, bioavailability, and potential risk of eight trace metals between summer and winter were analyzed using sequential analysis. The mean contents of all studied metals were higher than the geochemical background value, and were higher in summer than in winter. The results of the partitioning study indicated that Cr and Ni prevailed in the residual fraction, while a small proportion was found in the easily soluble fractions. Cu and Zn were distributed mainly in the residual and reducible fraction, while Cd and Pb were predominantly associated with non-residual fractions. These observations suggested that the most easily mobilized metals in the study area were Cd and Pb. The mean enrichment factors (EF) of Cu, Zn, Cd and Hg were higher than 1.5, revealing the potential anthropogenic inputs, whilst the EF of other metals remained within the range of natural variability. The positive correlation between non-residual Cu, Zn and Cd and their EF values further indicated that anthropogenic inputs were the potentially major contributor for the enrichment of Cu, Zn and Cd in TGR sediments. The results evaluated by both potential ecological risk index and modified risk assessment code (mRAC) of all sampling sites demonstrated the relatively high potential risk of sediment contamination effect in TGR.     

A new index for assessing heavy metals contamination in sediments: A case study

In this study, heavy metals contamination in surface sediments of northwest Persian Gulf was investigated and a new index was formulated for assessing severity of heavy metal pollution in aquatic environments. The surface sediment samples were collected from 45 stations. The concentrations of 8 metals (Fe, Cu, Zn, Cr, Ni, Pb, Cd and V) were analyzed. According to the results of potential ecological risk index (RI), pollution load index (PLI) and modified degree of contamination (mCD), based on the average shale, considerable and intense pollution of heavy metals in sediments of study area was not observed. Based on the sediments quality guidelines the concentration of Ni at whole study area has frequently adverse biological effect on aquatic organisms. The mean effects range-median quotient indicated that surface sediments in the vicinity of petrochemical zone and Bahrekan pier with 49% probability of toxicity can be risky for the biota. The Consequence of the cluster analysis and principal component analysis/factor analysis indicated that Fe, Cu, Zn and Cr are mainly originated from natural sources and Ni, Pb, Cd and V are mostly derived from anthropogenic sources. Results of introduced index in this research (Contamination Severity Index) demonstrated that pollution of heavy metals in sediments at several sites is very intense. Assessment of results illustrated that proposed index is more reliable and logical compared with other investigated indices for evaluating heavy metals pollution in sediments of aquatic environments.     

Heavy Metals (Cd,Cu, Ni,Pb, and Zn) Fractionation in River Sediments,Hamedan, Western Iran

Five heavy metals (Cd, Cu, Ni, Pb, and Zn) in river sediments from Abshineh River, Hamedan, western Iran, were fractionated by a sequential extraction procedure. Cu, Ni, Pb, and Zn existed in sediments mainly in residual fraction (mean 92%, 86%, 77%, and 65%, respectively), whereas Cd occurred mostly as organic matter (mean 41%) and exchangeable (mean 25%) fractions. The mean percent of mobile fraction of Cd, Cu, Ni, Pb, and Zn in contaminated sediments was 25, 13, 4, 24, and 10, respectively, which suggests that the mobility and bioavailability of the five metals in sediments probably decline in the following order: Cd = Pb > Cu > Zn > Ni. The metal levels were also evaluated according to the contamination factor, which revealed significant anthropogenic pollution of Cd and Pb.     

The Concentration and Partitioning of Heavy Metals in Surface Sediments of the Maharlu Lake,SW Iran

In this study, an assessment is made of the environmental impacts of heavy metal concentration and fractionation in bed sediments of the saline Maharlu Lake, SW Iran. Total elemental analysis indicated that sediments were highly enriched in Pb and Cd. Sequential extraction analysis revealed that salt of the lake is probably highly contaminated with Cd, Pb, and Co. Due to the oxidizing conditions of the lake, the organic matter fraction of the elements was not significant. In all sediments, Cd, Pb, Co, Mn, and Zn were strongly associated with exchangeable plus carbonate fractions, with mean percentage of 76.4%, 65.3%, 56%, 40.9%, and 34.3%, respectively. On average, the percentage of Ni associated with the sum of the exchangeable and carbonate fractions was 19.8%. Cr, Fe, and Cu fractionation indicated that these metals are environmentally inert and immobile. Statistical relationships among metal fractions and sediment properties showed that Cd, Pb, Zn, Ni, Co, and Mn were mainly from recent anthropogenic sources, while such sources were less important for Cr, Cu, and Fe. The latter metals represented natural geochemical levels.     

Distribution and risk assessment of heavy metals in river surface sediments of middle reach of Xijiang River basin,China

Xijiang River is the main surface water source in Guangxi province, South China. This study was carried out to investigate the distribution and potential ecological risks of seven heavy metals (Cu, Pb, Zn, As, Cd, Ni, and Cr) in surface sediments in Xijiang River basin. The results illustrated that the average concentrations of Zn, Pb, Cd, Cu, As, Ni, and Cr were 483.9, 207.5, 13.35, 23.50, 312.1, 28.75, and 50.62 mg/kg, respectively. Among them, Zn, Pb, Cd, and As were the major heave metals with concentration exceeding Class 3 threshold value of Chinese national standard. The result also showed samples with high ecological risk were mainly located in the upstream of Xijiang River basin as Diaojiang River, Hongshui River, Jincheng River, and Dahuan River. Based on the pollution risk assessment, the area manifested composite pollution of heavy metals in the sediments, signifying As, Pb, and Cd as the dominant heavy metals, and there were high ecological risk in sediments for these metals. According to correlation matrix and factor analysis (FA), the seven heavy metals were divided into three types/classes, Cd, as and Zn attributed by anthropogenic sources, natural sources corresponds for Ni and Cr while both natural and anthropogenic sources were attributed to Cu.     

Metal Pollution Assessment in Sediments of the Southeastern Black Sea Coast of Turkey

The main objective of this investigation is to determine the concentration and accumulation of heavy metals in the coastal sediments of the Southeastern Black Sea of Turkey. The selected sampling area has mainly been affected by anthropogenic activities, such as agricultural, untreated domestic and treated industrial wastewater, and mining. Metal enrichment factor (EF), geo-accumulation index (I_geo), and metal pollution index (MPI) have been calculated and relative contamination levels evaluated at all stations. In this study, the maximum EF values calculated for nickel (Ni), cobalt (Co), cadmium (Cd), lead (Pb), chromium (Cr), arsenic (As), zinc (Zn), and copper (Cu) were 1.4, 3.1, 5.2, 7.8, 7.8, 20, 26, and 42, respectively. Metal pollution has decreased in recent years, but the enrichment of heavy metals has been observed to be relatively high, especially in the uppermost 3-6 cm of the core sample from the Sürmene sampling station, which has been polluted by mining activities. In addition, factor analysis revealed that the coastal sediments from the Eastern Black Sea were influenced by several sources, namely lithogenic and anthropogenic activities (mining, wastewater discharging, agriculture).     

Distribution of heavy metals and their chemical speciation in sediments from the Abelardo L. Rodríguez Dam,Sonora, México

Abstract

The purpose of this study was to investigate the distribution of total and bioavailable metals (Cd, Cu, Cr, Fe, Mn, Pb and Zn) in sediments of the Abelardo L. Rodríguez (ALR) dam located in the eastern part of the city of Hermosillo, Sonora, Mexico. Seventy two sediment samples were collected in 2009 during four sampling campaigns in February (spring), May (summer), September (end of summer) and December (winter) in five different areas within the dam surface (Zones I, II, III, IV and V), including the Gate Station. Determination of heavy metals was carried out by flame atomic absorption spectrophotometry (FAAS). The results indicate high levels of total heavy metals in the following order: Fe>Mn>Zn>Pb>Cu>Cr>Cd. This is indicative of the impact of human activities located in areas surrounding the reservoir, specifically urban and industrial. The distribution and state of accumulation of trace metals in the sediment is largely dominated by the residual and Fe/Mn oxides geochemical phases. Fraction I (exchangeable) also presented high concentrations of metals (Cu, Fe, Mn and Zn). From enrichment factor analysis, the study area is prevalently enriched in Cd, Cu and Pb in Zones I, II, III, IV and Gate Station. This indicates that the sediments are impacted by anthropogenic activities such as downloads, domestic and industrial wastewater. Geoaccumulation index (Igeo) indicates that Zones I, II, III, IV and V (including Gate Station) do not show contamination by Cr, Fe, Mn and Zn. However, there is a moderate to heavy contamination by Cd, Cu and Pb (Igeo: 2–4) in all areas of study. The comparison between the results obtained with the sediment quality criteria (LEL and SEL), indicate that Zones I, II, III, IV, V and Gate Station, are contaminated with Cd, Cu and Pb, and severely contaminated by Fe.

The elevated levels of heavy metals detected in the sediment of the ALR Dam require special attention, since in the exchangeable fraction, the metals are specifically adsorbed on the sediment and can be released when the ionic composition of water changes. However, additional studies are required in this reservoir on the chemistry and toxicology of metals for a full assessment of potential risks posed to biota and man.     

Heavy metal contamination in vegetables grown around peri-urban and urban-industrial clusters in Ghaziabad,India

Heavy metal contamination of agricultural soils resulting from rapid industrialization and urbanization is of great concern because of potential health risk due to dietary intake of contaminated vegetables. The present study aims to evaluate the status of heavy metals contamination of agricultural soils and food crops around an urban-industrial region in India. Transfer factor values of Cu, Cr, Pb, Cd, Zn, and Ni from soil to vegetable was estimated. The mean heavy metal concentrations (mg/kg) in agricultural soils (Cu: 17.8, Cr: 27.3, Pb: 29.8, Cd: 0.43, Zn: 87, Mn: 306.6, Fe: 16984, and Ni: 53.8) were within allowable concentrations for Indian agricultural soil. The concentrations of Pb, Cd, Zn, and Ni in crops/vegetables exceeded the World Health Organization/Food and Agriculture Organization safe limits. Relative orders of transfer of metals from soil to edible parts of the crops/vegetables were Cd > Pb > Ni > Zn > Cu > Cr. The enrichment factors of heavy metals in soil indicated minor to moderately severe enrichment for Pb, Cd, and Ni; minor to moderate enrichment for Zn; no enrichment to minor enrichment for Mn; and no enrichment to moderate enrichment for Cu at different sites. Ecological risk index of soil showed considerable contamination in one of the wastewater irrigated sites.     

Heavy Metal Partitioning in Bottom Sediments of the Matanza-Riachuelo River and Main Tributary Streams

This study provides geochemical partitioning, potential bioavailability, and enrichment of Cd, Cu, Pb, and Zn in bottom sediments collected from the Matanza-Riachuelo River and its main tributary streams. A modified Tessier sequential extraction procedure, complemented with acid volatile sulfide (AVS) and simultaneous extracted metals (SEM) measurements, was applied to determine the partitioning of metals into four fractions (metals bound to amorphous sulfide, carbonate, and exchangeable), bound to Fe/Mn oxides (reducible), bound to organic matter/sulfide (oxidizable) and residual. Spatial and vertical distributions of metals were studied. The core sediments show a decreasing concentration of metals with depth. In top sediments, non-residual Cu was mainly associated with oxidizable phase, whereas Pb, Cd, and Zn were mainly associated with amorphous sulfide. Pb exhibited the highest enrichment in all sites. The ratio AVS/SEM was greater than one at sediment sections close to the water column, indicating that metals extracted with hydrochloric acid were mainly associated with the amorphous sulfide. The strong influence of amorphous sulfide in the retention of Cd, Pb, and Zn in anoxic sediments of Matanza-Riachuelo river system suggests that dredging and aeration could lead to the remobilization of metals from sediments to the water column, hence making the metals more available to the biota.     

Heavy metals in surface sediments of lakes in Guangzhou public parks in China and their relations with anthropogenic activities and urbanization

This study aimed to investigate the pollution of heavy metals in the sediments of park lakes in Guangzhou, which is a large city with rapid urbanization, industrialization, and dense population in South China. Thirty-two surface sediment samples were collected from seven lakes in different districts of this city. The concentrations and distributions of Cr, Ni, Cu, Zn, Cd, and Pb were measured to assess the level of enrichment and toxicity in the sediments. The enrichment factor showed that Pb and Zn showed severe enrichment in all lakes except for the Dafu Shan Forest Park (DFS), and the geo-accumulation index (I_geo) showed that all lakes were polluted with Cu, Pb, Cd, Ni, and Zn in different levels. The results of risk assessment indicated that the DFS located in the suburbs represented moderate risks; however, other lakes in the city central represented high or very high risks. Moreover, Cd had the primary contribution to the risk of the sediments' environment in urban lakes. Multivariate statistical analyses are carried out to explore the correlativity between heavy metals and human development indices. This study indicated that the levels of heavy metals' contamination and ecological risk of urban lakes in Guangzhou have a close relationship with anthropogenic activities.     

Dissemination of heavy-metal contamination in surface sediments of the Uzunçayır Dam Lake,Tunceli, Turkey

The objective of this study was to determine the heavy-metal concentrations (Cu, Pb, Zn, Ni, Mn, Fe, As, Cd, Cr, and Hg), evaluate the pollution levels, and determine the concentration of chlorophyll-a and organic carbon in the surface sediments of the Uzunçay?r Dam Lake, Tunceli, Turkey, between 2015 and 2016. In order to evaluate the effect of the pollution level in the study area, the contamination factor (CF), enrichment factor, potential ecological risk index, and pollution load index were used. The concentrations of the studied heavy metals were ordered as follows: Fe > Mn > Ni > Cr > Zn > Cu > Pb > As > Cd > Hg. The highest CF value was found for the Ni element among the studied heavy metals in the Dam Lake. Moreover, the highest CF mean value was found for the As contamination level. According to the toxicity analyses in the study area, the potential toxic effect of sediments was not at a very serious level.     

Evaluation of Soil Contamination Indices in a Mining Area of Jiangxi,China

There is currently a wide variety of methods used to evaluate soil contamination. We present a discussion of the advantages and limitations of different soil contamination assessment methods. In this study, we analyzed seven trace elements (As, Cd, Cr, Cu, Hg, Pb, and Zn) that are indicators of soil contamination in Dexing, a city in China that is famous for its vast nonferrous mineral resources in China, using enrichment factor (EF), geoaccumulation index (I_geo), pollution index (PI), and principal component analysis (PCA). The three contamination indices and PCA were then mapped to understand the status and trends of soil contamination in this region. The entire study area is strongly enriched in Cd, Cu, Pb, and Zn, especially in areas near mine sites. As and Hg were also present in high concentrations in urban areas. Results indicated that Cr in this area originated from both anthropogenic and natural sources. PCA combined with Geographic Information System (GIS) was successfully used to discriminate between natural and anthropogenic trace metals.     

Assessment of metals in agricultural soil of surrounding areas of Urmia Lake,northwest Iran: A preliminary ecological risk assessment and source identification

The aim of this study was to quantify the levels of toxic heavy metals and sodium in topsoil of farmlands around the Urmia Lake. A total of 96 topsoil samples were collected, pre-treated, and analyzed for metals using ICP-AES.

Median concentrations of As, Cd, Cu, Ni, Pb, Zn, and Na in sampling sites were 5, 0.26, 30, 40, 13, 84, and 251 mg/kg, respectively. The enrichment factor, geoaccumulation index, and contamination factor of the metals ranked them in the order of: Na > Pb > Cu > As > Cd > Zn > Ni, indicating minor contamination for them except Na and Pb with moderate contamination. Furthermore, the spatial analysis indicated that Cd, Cu, Pb, Ni, and Zn had similar distribution patterns in the north and northwest lands of the lake. Principal component analysis revealed anthropogenic sources for Cd, Cu, Ni, Pb, and Zn in the soil, whereas, sources of As and Na were most likely related to the dust emitting from the dried bed of Urmia Lake and from a cement industry. Potential ecological risk index in 7% of the sampling sites was at serious or considerable pollution level, and Cd and Pb were identified as the main pollutants.     

Levels,solid-phase fractions and sources of heavy metals at site received industrial effluents: a case study

Heavy metals in the site received industrial effluents were investigated to assess the pollution levels, distribution of metal among solid-phase fractions and possible metal sources. The soil samples at different depths of 0–5, 5–25 and 25–50 cm were collected and analyzed for Fe, Mn, Cd, Zn, Cu, Ni and Pb. Among all metals, Cd content was not detected in all soil samples. The average contents of Pb and Zn are higher than the corresponding values of common range in earth crust. Meanwhile, the maximum contents of Cu and Zn are higher than those of Dutch optimum value but lower that the Dutch protection act target value. The maximum contents of Cu, Pb and Zn are higher than the average shale value. The most investigated heavy metals are mostly found in the potentially labile pool (>50.0%) including metal bound to carbonate, Fe/Mn oxides, or organically fractions. Enrichment factor (EF) in combination with multivariate analysis including principal component analysis (PCA) and hierarchical cluster analysis (HCA) suggest that Mn and Ni associated with Fe in the soil samples were primarily originated from lithogenic sources. Pb was largely derived only from anthropogenic source, while Cu and Zn in the soil samples were controlled by the mixed natural and anthropogenic sources. These results suggest that discharging the industrial effluents into dumping site increased pollution level of Pb, Zn and Cu as well as enhanced their potentially labile pool that may be responsible for occurring potential toxic impacts on environmental quality.     

Contamination and environmental risk assessment of heavy metals in marine sediments from Tahaddart estuary (NW of Morocco)

Abstract

The distribution, contamination status, and ecological risks of heavy metals in Tahaddart estuary were investigated. 24 surface sediment samples and two cores were collected and analyzed for major (Al and Fe), heavy metals (As, Cd, Cr, Cu, Ni, Pb, and Zn), and grain size composition. The heavy metals assessment was carried out using different environmental indices. The results indicated that the spatial distribution patterns of Al, Fe, and Zn were mainly determined by the distribution of the finer grained fraction (<63?μm) in the sediment. In contrast, As, Cd, Cr, Cu, Ni, and Pb concentrations were controlled by anthropogenic activities (vehicular traffic from Highway Bridge and thermal power plant). The distribution of heavy metals in sediment cores showed an upward enrichment in heavy metals with high concentration found in the uppermost may related to the increasing in human activities. The pollution indexes confirmed that the Tahaddart estuary sediment was considerably to high contaminated by heavy metals near to different anthropogenic inputs. Similarly, the potential ecological risk index and the biological risk index present 21% probability of toxicity posing potential risk to the aquatic organisms. These results provide basic information that can be used to protect and improve the quality of this ecosystem.     

浙江油茶产地土壤和果实金属元素含量特征

为探讨油茶(Camellia oleifera)产地土壤和油茶果实中金属元素分布和富集特征,在油茶果实成熟期,对浙江5个油茶产地土壤及油茶果实中金属元素进行污染分析和富集能力评价.结果表明,浙江油茶产地土壤中Pb、Cr、Cd、As、Hg、Ni、Cu和Zn含量低于农用地土壤污染风险筛选值,综合污染等级为安全.个别产区常山...     

Heavy Metal Contamination of Soil,Plant and Air of Scrapyard of Discarded Vehicles at Zarqa City,Jordan

Ninety soil samples, forty plant samples (Anabasis articulata), and twenty air samples were collected from the scrap yard of discarded vehicles near Zarqa city, Jordan. These samples were analyzed for heavy metals: Cd, Pb, Zn, Cu, Mn, Al, and Fe. Longitudinal and vertical profiles of soil samples were studied. Generally, the levels of all heavy metals studied in the scrap yard area were found to be higher than those of the control samples. The levels of heavy metals decreased with depth until reaching a constant value at 9 cm depth. The levels of heavy metals also decreased at distances farther away from the scrap yard area. A significant difference in heavy metal concentrations was found between washed and unwashed plant samples. On the other hand, no significant differences have been found between plant samples from inside and outside the scrap yard area. Air samples showed wide variations in heavy metal levels among the sampling sites. The enrichment factors for non-crustal elements such as Pb, Cd, Cu, and Zn, in both soil and particulate matter, were found to be more than 10, indicating anthropogenic sources such as dust, rust, and exhaust emissions from the scrap yard area, whereas the crustal elements such as Fe and Mn showed enrichment factors of less than 10.     

Assessment of Heavy Metals Pollution in Sediments of the Korbevačka River in Southeastern Serbia

The Korbeva?ka River is located in the southeastern part of Serbia. This river is a main recipient of all kinds of pollutants from the Pb?Zn mine “Grot.” Sediments from the Korbeva?ka River were studied to determine the distribution of the metals along the river, assess the quality of sediment, and find the degree of contamination. The concentration of iron, manganese, nickel, copper, zinc, cadmium, lead, mercury, arsenic, chromium, and barium were determined. River sediments were collected and analyzed for heavy metal concentration using atomic absorption spectrophotometer. The degree of pollution in the sediments of the Korbeva?ka River has been evaluated based on Canadian sediment quality guidelines, enrichment factor (EF), geo-accumulation index (I_geo) and pollution load index (PLI). Inter-metal associations have been evaluated by Pearson correlation coefficients (r). The results indicated that: (1) sediments have been polluted with Pb, Cd, Zn, and Cu and have high anthropogenic influences; (2) the calculation of geo-accumulation index suggests that the Korbeva?ka River sediments have background concentrations of Fe, Cr, and Ni (I_geo < 1); (3) the co-precipitation (inclusion, occlusion, and adsorption) of heavy metals (except As and Ba) with Mn and Fe geochemical phases.     

Heavy Metal Contamination in Sediments and Floodplain Topsoils of the Lean River Catchment,China

Heavy metals (Cd, Ni, Cu, Pb, and Zn) and total sulfur (TS) in both surficial sediments and adjacent floodplain topsoils of the Lean River catchment are investigated to comprehend the effects of flooding on heavy metals in soils, the evolution of the quality of sediments, and transfer of sediment metals. The results show that concentrations of metals except for Ni in soils are significantly correlated with those in sediments. At most upstream or downstream locations, sediment metal concentrations are found comparable to those in soils (sed/soil≈1). For Cu at locations close to the Dexing Copper Mine (DCM), flooding brought Cu-poor clays into the floodplain soil system and this leads to sed/soil<1, while at locations adjacent to the Yinshan Lead-zinc Mine (YLM), suspended solids containing high concentrations of iron and magnesium oxide absorb large quantities of dissolved Cd, Pb, and Zn and deposit on the floodplain during flooding (sed/soil>1). In spite of an elevated Cu production of the DCM, a significant decrease in sediment Cu concentrations is found as compared to those 10 years ago. The decrease may be due to the elevated Cu ore utilizing efficiency and the use of a new modern tailing pool. At the location closest to the Yinshan Lead-zinc Mine (YLM), Pb and Zn concentrations increased in recent sediments. In the Lean River, metal contamination in sediments cannot reach the location 60 km downstream of their sources in 2005.     

Distribution and contamination pattern of heavy metals from surface sediments in the southern part of Caspian Sea,Iran

This study concentrates on the speciation and distribution patterns of some heavy metals (Pb, Ni, Cd, Zn, and Cu) in surface sediments in the southern part of the Caspian Sea, the biggest lake in the world, to obtain an overall classification for the origins of metals in the area using a sequential extraction technique. At all sampling stations, Pb, Ni, Zn, and Cu were mostly (>50%) accumulated in the resistant fraction, which indicated that there were no significant anthropogenic inputs of Pb, Ni, Zn, and Cu into the surface sediments of the south Caspian Sea. Guilan province on the west coast of Caspian Sea accumulated higher percentages of non-resistant fractions of Pb and Zn, while Mazandaran and Golestan provinces in the middle and western parts of the Caspian Sea, in the Iranian zone, accumulated higher percentages of non-resistant fractions of Ni and Cu. The present study revealed that the coastal area of the south Caspian Sea is still not seriously contaminated. Cadmium in Guilan and Golestan provinces were dominated by non-resistant fractions (55–69%), which indicated more anthropogenic inputs of Cd on the south coast of the Caspian Sea in comparison with other metals.