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1.
In order to investigate the pollution levels, sources and ecological risks of arsenic (As) and heavy metals (Cr, Ni, Cu, Zn, Pb and Cd) in inshore sediments of the Yellow River estuary, the surface sediment in areas of inshore coastal waters were sampled in October 2014 as the flow-sediment regulation project (FSRP) was implemented for 13 years. Results showed that the concentrations of As and heavy metals in inshore sediments of the Yellow River estuary were in the order of Zn?>?Cr?>?Cu?>?Ni?>?Pb?>?As?>?Cd. Higher levels of As, Cr, Ni, Cu, Zn and Pb generally occurred in fine-grained sediments of the Yellow River estuary and the southeast region, which was consistent with the spatial distribution of clay. In contrast, higher concentrations of Cd were generally observed in northwest area of the Yellow River estuary and near the Qingshuigou estuary, which showed similarly spatial distribution with that of sand. The sediment quality guidelines (SQGS) and geoaccumulation indices (Igeo) indicated that the inshore sediments were polluted by Cu, Cd, As, Pb and Zn, and, among them, Cd pollution was more serious. Ecological risk indices (E r i ) demonstrated low risks for Cr, Ni, Cu, Zn, Pb and As, and high potential toxicity by Cd. The integrated ecological risk index implied that 6.8% of stations presented moderate risk, 4.5% of stations exhibited disastrous risk, and 88.7% of stations demonstrated considerable risk. Principal component analysis indicated that Ni, Cu, Zn, Pb and As might originate from common pollution sources, while Cr and Cd might share another similar sources. With the continuous implementation of FSRP, As and heavy metal levels in inshore sediments of the Yellow River estuary could be classified as stage I (2002–2010) and stage II (2010–2014). In the stage I, As, Cr, Ni, Cu, Zn and Pb levels fluctuated but decreased significantly, whereas Cd concentrations showed little variation. In the stage II, As and heavy metal levels significantly increased although some little fluctuations occurred. The continuous accumulation of As and heavy metals (especially for Cd) in inshore sediments of the Yellow River estuary would occur again as the FSRP was implemented for 9 years (since 2010). The ecotoxicological risk of Cd, As, Ni and Cu in inshore sediments might be more serious since the accumulation of the four elements would be continuously occurred in future years. Next step, there will be long-term potential consequences for marine organism if effective measures are not taken to control the loadings of metal pollutants into estuary.  相似文献   

2.
In the heavily industrialized Masan Bay of southern coast, Korea, the potential harmful effects of heavy metals (Cd, Co, Cu, Ni, Pb, Sn, Zn, and Hg) were evaluated in terms of the pollution load index (PLI) and ecological risk assessment index (ERI) methods, and the results obtained were considered alongside the health of the macrobenthic fauna communities. The results revealed that the bay sediments, especially in the inner bay and the outfall area of a sewage treatment plant, are exposed to moderate to serious levels of metal pollution. Hg and Cd contributed the most to the potential toxicity response indices in sediments recently deposited in the bay. The potential ecological risk assessment of heavy metals in the bay was highlighted by the use of the benthic biological pollution index (BPI), suggesting that the ERI is a useful toxicity response index, which can quantify the overall ecological risk level to a target environment.  相似文献   

3.
《国际泥沙研究》2016,(2):164-172
The ecological risk assessment for Al,Zn,Cu,Ni,V,Pb,Cd,and Hg in surface sediment collected from the Egyptian Red Sea coast was evaluated using the Geo-accumulation Index(I_(geo)).Sediment Enrichment Factor(SEF) and Potential Ecological Risk Index(PERI) methods.The predominant heavy metal,aluminum,showed high concentrations along both of Aqaba Gulf(4378.8 ± 2554.1 μg/g) and southern part of the Red Sea(2972.8 + 1527.5 μg/g).while it recorded the lowest concentration in Suez Gulf(829.7 ± 398.2 μg/g).The determined heavy metal concentrations had the order of Al Zn -Ni V Pb Cu Cd Hg.The statistical analyses showed some correlations among the heavy metals contents.Several international sediment quality guidelines were used to estimate the quality of the collected sediments.Interestingly,the recorded average heavy metals concentrations were lower than those of the permissible contents for sediment quality guidelines.The Geo-accumulation index calculations(I_(geo)) proved that the investigated region could be classified as an unpolluted area.Sediment Enrichment Factor(K_(SEF)) study showed high values in Suez Gulf region.The single pollution index analysis of heavy metals in the sediments(C~i_f) indicated that Al,Zn,V,and Pb were of natural origin,while Ni,Cd and Hg were seriously affected by human activities.Interestingly,amongst,all the determined heavy metals,Cd and Hg gave moderate ecological risk indicators.  相似文献   

4.
典型小型水库表层沉积物重金属分布特征及生态风险   总被引：2，自引：1，他引：1  
以典型乡镇水库通济桥水库表层沉积物为研究对象,在分析其中As、Cd、Cr、Cu、Hg、Ni、Pb和Zn等有毒、有害重金属分布特征的基础上,分析重金属来源,评价重金属污染程度及其潜在生态危害.结果表明:通济桥水库表层沉积物中,上述8种重金属均存在一定程度的污染,坝前和入库区污染物蓄积更为明显.其中,Hg和Cd的污染范围较广、污染程度较严重.受重金属Hg和Cd的影响,水库表层沉积物存在中等程度的重金属生态危害风险,其中坝前区域已处于强风险等级.为保障水库水体水质安全,防范重金属污染应提到当前水库管理工作的重要位置.  相似文献   

5.
In the recent years,the Red Sea coast of Yemen has been severely affected by intensive anthropogenic activities.The current study constitutes a thorough inquiry to evaluate the extent of heavy metals pollution in Yemen's Red Sea coast sediment and identifies the possible sources of pollution.The concentrations of five metals(copper(Cu),zinc(Zn),cadmium(Cd),lead(Pb),and nickel(Ni))collected from nine sites along the Red Sea coast of Yemen were assessed using an atomic absorption spectrophotometer(ASS).Sediment quality indices,such as the sediment quality guidelines(SQGs),potential ecological risk(RI),contamination factor(CF),pollution load index(PLI),geoaccumulation index(Igeo),and modified degree of contamination(mCd)were computed.In addition,multivariate statistical techniques(principal component analysis(PCA),hierarchical cluster analysis,and Pearson's correlation analysis)were applied to identify the potential sources of metals.The mean concentrations of Cu,Zn,Cd,Pb,and Ni were 51.3,61.9,4.02,9.9,and 33.4 mg/kg dry wt,respectively.The spatial distribution revealed that the metals concentrations were high at the middle zone and low southward of Hodeida city.According to the SQGs,the adverse biological effects of metals were occasionally associated with Cu and Cd,frequently associated with Ni,and not expected to occur with Zn and Pb.The RI indicated that the sediment of the studied sites pose low(RI<50)to considerable(100≤RI<200)ecological risk.The mean effect range-median quotient(M-ERM-Q)indicated that the combination of the studied metals had the toxicity probability of 21%at all studied sites.Igeo and CF indicated that the metals concentrations were in the descending order of:Zn>Ni>Pb>Cd>Cu,whereas the PLI and mCd indicated that Ras Isa(Site 5)and Urj village(Site 6)were the most polluted sites.PCA,cluster analysis,and correlation analysis found that Cd,Pb,and Ni mostly originated from anthropogenic sources while Cu and Zn were mainly derived from natural sources.Thus,it is evident that the intensive anthropogenic activities had negative influence on metals accumulation in the sediment of the Red Sea coast of Yemen leading to detrimental effects to the whole ecosystem.These comprehensive findings provide valuable information and data for future monitoring studies regarding heavy metals pollution and sediment quality at the Red Sea coast of Yemen.  相似文献   

6.
为评估滆湖围网拆除工程实施效果,采用高密度网格化布点方法,系统分析滆湖沉积物营养盐和重金属的空间分布和污染特征;并基于有机氮评价方法、综合污染指数评价方法、重金属地质累积指数法和重金属潜在生态风险评价方法进行污染风险评价.结果表明,滆湖沉积物总氮(TN)、总磷(TP)和总有机碳(TOC)的平均含量分别为(3709±1004)mg/kg、(1127±650) mg/kg和(78.39±23.88) mg/g,三者空间分布特征较为一致;营养盐综合污染指数评价表明,全湖整体为重度污染,其中全湖TN均处于重度污染状态,TP绝大部分区域也处于重度污染状态.沉积物重金属Zn、Cr、As、Pb、Ni、Cu、Cd 的平均含量分别为(170.62±47.25)、(105.18±34.91)、(68.55±10.86)、(52.43±14.73)、(44.04±11.93)、(42.57±12.43)、(1.55±1.06) mg/kg,整体上呈现出由南向北、自西向东逐渐增加的趋势,重金属含量最高值在湖区东北角;地积累指数法和潜在生态风险指数法评价结果均表明Cd和As是主要的生态风险贡献因子,其中Cr和Ni的污染程度表现为清洁,Cr、Ni、Cu、Zn和Pb的单项潜在生态风险等级表现为轻微风险.与围网拆除前比,湖中区西南部沉积物营养盐含量无显著变化,湖南区南部沉积物营养盐状况明显改善,但其余各区域沉积物营养盐状况均有不同程度的恶化;湖区沉积物中重金属元素平均含量均有极大程度的降低,降幅在29.50%～80.45%之间,表明在外源污染输入得到一定控制时,围网拆除在控氮、控磷效果及改善重金属污染状况方面有着积极作用.  相似文献   

7.
River water and sediment embody environmental characteristics that give valuable eco-environmental information.Due to rapid industrialization,the aquatic environment of any urban river can be seriously polluted by heavy metals（HMs）.The global concern is caused by heavy metal pollution because of its potential harm to aquatic ecosystems and human health.In the Bhairab River,Bangladesh,surface sediment concentrations of globally alarming toxic metals such as arsenic（As）,chromium（Cr）,cadmium（Cd）,an...  相似文献   

8.
分析了阳宗海柱状及表层沉积物中Al、Fe、Mn、Zn、Cr、Co、Ni、Cu、As、Cd、Pb等金属元素的含量,结合沉积年代学,研究了沉积物重金属污染的时空变化和潜在生态风险特征.结果表明,表层沉积物中重金属含量具有一定的空间差异性,As、Cd、Cu、Pb和Zn在中东部湖区含量较高,而Cr、Co、Ni含量高值位于南、北湖区的近岸区域;柱状沉积物中,1990s之前As、Cd、Cu、Pb和Zn含量较为稳定,1990s中后期以来,其含量逐渐增加,并在2009-2010年前后达到最大值,此后逐渐下降;而柱状沉积物中Cr、Co、Ni含量变化趋势与Al、Fe相似,总体上由下向上逐渐降低,这主要与沉积物质地(粒度)逐渐变粗有关.重金属富集系数表明,阳宗海沉积物中主要污染元素为As、Cd、Cu、Pb和Zn,1990s中后期污染程度快速增加,2009-2010年前后达到峰值,此后污染程度逐渐降低;表层沉积物中Cu为未污染至"弱"污染水平;Zn、Pb为"弱-中等"污染水平,As为"中等-强"污染水平,Cd为"弱-强"污染水平,中东部湖区污染程度高于其他湖区,这可能与该湖区缺少入湖径流、自然碎屑物质沉积速率较低以及砷污染事件等人为源的重金属贡献影响更为显著有关.生态风险评价结果表明,在2002-2010年前后沉积物重金属达到"中等-强"潜在生态危害,主要贡献因子是Cd和As,近年来其生态风险等级逐渐降低;表层沉积物中重金属在中东部湖区具有"中等"程度潜在生态危害,而其他湖区表层沉积物重金属具有较低程度的潜在生态风险.  相似文献   

9.
The aim of this study was to assess the level of heavy metals (Al, Cd, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) contamination and enrichment in the surface sediments of the Seyhan River, which is the receiving water body of both treated and untreated municipal and industrial effluents as well as agricultural drainage waters generated within Adana, Turkey. Sediment and water samples were taken from six previously determined stations covering the downstream of the Seyhan dam during both wet and dry seasons and the samples were then analyzed for the heavy metals of concern. When both dry and wet seasons were considered, metal concentrations varied significantly within a broad range with Al, 7210–33 967 mg kg?1 dw; Cr, 46–122 mg kg?1 dw; Cu, 6–57 mg kg?1 dw; Fe, 10 294–26 556 mg kg?1 dw; Mn, 144–638 mg kg?1 dw; Ni, 82–215 mg kg?1 dw; Pb, 11–75 mg kg?1 dw; Zn, 34–146 mg kg?1 dw in the sediments while Cd was at non‐detectable levels for all stations. For both seasons combined, the enrichment factor (EF) and the geo‐accumulation index (Igeo) for the sediments in terms of the specified metals ranged from 0.56 to 10.36 and ?2.92 to 1.56, respectively, throughout the lower Seyhan River. The sediment quality guidelines (SQG) of US‐EPA suggested the sediments of the Seyhan River demonstrated “unpolluted to moderate pollution” of Cu, Pb, and Zn, “moderate to very strong pollution” of Cr and Ni. The water quality data, on the other hand, indicated very low levels of these metals suggesting that the metal content in the surface sediments were most probably originating from fine sediments transported along the river route instead of water/wastewater discharges with high metal content.  相似文献   

10.
We conducted an analysis of heavy metals content, including As, Cd, Cr, Cu, Hg, Pb, and Zn in sediments from aquatic ecosystems in China measured in recent publications. Then, we evaluated the extent of heavy metal pollution in these ecosystems in seven different industrial districts in China (Dongbei, Huabei, Huazhong, Huanan, Huaxik, Xibei, and Huadong) with the potential ecological risk index. We found that Cd was the most concentrated pollutant, followed by Hg and As, while Cr, Cu, Pb, Zn were found in low concentrations in sediments from all types of aquatic ecosystem in China. Sediments collected from all seven industrial districts were heavily polluted, and the sequence, from most to least polluted was Dongbei>Huabei>Huazhong>Huanan>Huaxi>Xibei>Huadong. All four types of aquatic ecosystem were found to be seriously polluted and the sequence, from most to least polluted was: river>sea>lake>wetland. Specifically, Cd and Hg were the most serious pollutants in all four aquatic ecosystems, and As was also a serious pollutant in rivers. For the seven industrial districts studied the sea was the most polluted ecosystem in Dongbei, the river was the most polluted ecosystem in Huabei, Huanan, Huazhong, and the lake was the most polluted in Huadong, Huaxi, and Xibei.  相似文献   

11.
An overall and comparative ecological risk assessment of heavy metals (including Cd, Cr, Cu, Pb, Zn, Hg and As) in surface sediments from China’s eight major aquatic bodies was conducted to better understand their potential risks on a national scale. By applying the joint approach of Hakanson risk index (RI) and Monte Carlo simulation, ecological risk in this work is expressed as probability distribution of RI values instead of single point calculations to reflect the uncertainties in risk assessment process. The results show that the highest ecological risks posed by heavy metals existed in Xiangjiang River and Dianchi Lake. Although only a slim margin of high risk (651.88/600 = 1.08 and 700.61/600 = 1.17) was identified based on average RI values, the probabilities of high risk level derived from Monte Carlo simulation reached as high as 56.7 and 52.9 % in these two aquatic bodies, respectively. And the probability of low risk level was less than 1.6 %. Furthermore, the risk was mainly contributed by Hg and Cd, discharged through local intensive mining and industrial activities. The findings indicate that rigid control and effective management measures to prevent heavy metal pollution are urgently needed in China, especially for the high-risk aquatic bodies. This study shows that the joint approach can be used to identify the high risk water bodies and the major metal pollutants. It may avoid overestimating or underestimating the ecological risk and provide more decision-making support for risk alleviation in the polluted aquatic bodies.  相似文献   

12.
The heavy metal inventory and the ecological risk of the estuarine sediments in Hailing Bay, an important maricultural zone along the southern coast of China, were investigated. Results show that the surface sediments were mainly polluted by As (2.17-20.34 mg/kg), Ni (1.37-42.50mg/kg), Cu (1.21-58.84 mg/kg) and Zn (11.69-219.22 mg/kg). Furthermore, the aquafarming zone was significantly more polluted than the non-aquafarming zone, and cluster analysis suggested additional sources of heavy metal input in the aquafarming zone. As, Cr, Cu, Ni, Pb and Zn were mainly present in the non-bioavailable residual form in the surface sediments, whereas Cd was predominantly in the highly mobile acid soluble and reducible fractions. The ecological risk of the polluted sediments stemmed mainly from Cd, and from As, Cu and Pb to less degrees. The highest potential risks occurred near the aquaculture base, indicating the need to control heavy metal inputs from aquafarming activities.  相似文献   

13.
白洋淀沉积物-沉水植物-水系统重金属污染分布特征   总被引：6，自引：1，他引：5  
通过对白洋淀沉水植物及对应沉积物和水中Cd、Pb、As含量测定，以期揭示白洋淀沉积物-沉水植物-水系统中重金属污染状况及分布规律，明确不同沉水植物对重金属的富集能力.结果表明，地表水Cd、Pb、As浓度均符合我国地表水I类水质标准，不同采样区重金属浓度差异不显著.上覆水Pb浓度显著高于地表水和间隙水，间隙水As浓度显著高于地表水和上覆水；地积累指数法和潜在生态危害指数法评价结果表明，沉积物中重金属污染程度表现为Cd > Pb > As，Cd污染最严重，达到"轻度-偏重度"污染程度，"中等-极强"生态危害级别，As为清洁水平，不同采样区重金属污染程度表现为生活水产养殖区 > 纳污区 > 淀边缘区；沉水植物重金属富集能力表现为金鱼藻（Ceratophyllum demersum L.） > 菹草（Potamogeton crispus L.）和穗状狐尾藻（Myriophyllum spicatum L.） > 篦齿眼子菜（Potamogeton pectinatus L.）.植物体内重金属含量与体内氮、磷含量呈显著正相关，氮、磷营养盐影响沉水植物对重金属的富集.  相似文献   

14.
武汉典型湖泊沉积物中重金属累积特征及其环境风险   总被引：20，自引：1，他引：19  
采集武汉市8个典型湖泊的表层沉积物,分析11种重金属的含量及其不同形态组成,研究了不同湖泊金属元素的富集与污染程度,探讨了沉积物中重金属的污染来源及其潜在生态风险,结果表明,沉积物中重金属Cd累积最严重,Zn和Hg也发生明显累积,龙阳湖污染较重,南太子湖和墨水湖污染中等,其它湖泊污染总体较轻.沉积物性质对重金属累积的影响不显著,城市工业活动强烈影响着重金属的分布,不同重金属的形态分布差异较大,Cd生物可利用态含量最高,其次为Mn、Zn、Co、Cu和Pb;而Sb和Hg以残留态占绝对优势,生态风险较小,相关分析和主成分分析表明,化石燃料燃烧、金属冶炼等是武汉市湖泊沉积物中重金属来源的主要贡献者,同时岩石风化等地球化学过程也影响着重金属的污染.  相似文献   

15.
太湖流域滆湖底泥重金属赋存特征及其生物有效性   总被引：1，自引：0，他引：1  
包先明  晁建颖  尹洪斌 《湖泊科学》2016,28(5):1010-1017
为了探讨太湖流域滆湖底泥重金属(Cd、Cr、Cu、Zn、Ni和Pb)的赋存特征及其生物有效性,对底泥重金属总量、形态以及生物富集量进行了分析.结果表明,6种重金属含量的空间分布表现为北部湖区最高,其次为南部湖区,中部湖区最低,重金属Ni、Cu、Zn和Pb含量显著高于沉积物背景值,分别是背景值的4.77、3.89、2.96和2.76倍,重金属总量与沉积物中的黏土成分含量具有显著相关性.采用三级四部提取法对重金属形态进行分析表明,6种重金属的生物有效态(弱酸结合态、可还原态和可氧化态之和)含量顺序为CdCuZnPbNiCr,其中Cd、Cu、Zn和Pb的生物有效态含量分别占总量的84.15%、78.47%、76.50%和64.29%.Cu和Zn在铜锈环棱螺中富集含量要显著高于其他金属元素.相关性分析表明,6种重金属中仅Cr和Pb的生物富集量与有效态含量具有显著相关性,这表明,重金属在生物体内的富集不仅与有效态含量有关,还与底泥重金属总量有关.因此,评价滆湖重金属的生态风险时需要综合考虑重金属的总量及生物有效态含量.  相似文献   

16.
A geographically extensive investigation was carried out to analyze the concentrations of heavy metals, PCBs and OCPs in the sediments and marine organisms collected from the Liaohe Estuary. In order to determine the spatial distribution and potential ecological risk of heavy metals, the surface sediments were collected from 44 sites in the Liaohe Estuary. The results showed that the heavy metal contents in the sediments were observed in the following order: Cr (11.2–84.8 mg/kg) > Cu (1.7–47.9 mg/kg) > Pb (4.3–28.3 mg/kg) > As (1.61–12.77 mg/kg) > Cd (0.06–0.47 mg/kg) > Hg (0.005–0.113 mg/kg). In comparison with the concentrations of heavy metals and POPs in other regions, the concentrations of As, Pb and DDTs in the Liaohe Estuary were generally low, and other pollutant concentrations were inconsistent with those reported in other regions. The contamination factor (CF), the pollution load index (PLI), the geoaccumulation index and the potential ecological risk index were used to analyze the pollution situation, which showed that the heavy metal pollution in Liaohe Estuary is mainly dominated by Cd and Hg. The concentrations of the four heavy metals varied significantly in the three kinds of tested organisms (fish, mollusk and crustacean), indicating the different accumulative abilities of the species. The results obtained in this study provide useful information background information for further ecology investigation and management in this region.  相似文献   

17.
Total metal concentrations (Cr, Ni, Cu, Zn, and Pb), acid volatile sulfide and simultaneously extracted metals (AVS-SEM), and heavy metal fractionation were used to assess the heavy metals contamination status and ecological risk in the sediments of the Pearl River Estuary (PRE) and adjacent shelf. Elevated concentrations at estuarine sites and lower concentrations at adjacent shelf sites are observed, especially for Cu and Zn. Within the PRE, the concentration of heavy metals in the western shore was mostly higher than that in the middle shore. The metals from anthropogenic sources mainly occur in the labile fraction and may be taken up by organisms as the environmental parameters change. A combination of total metal concentrations, metal contamination index and sequential extraction analysis is necessary to get the comprehensive information on the baseline, anthropogenic discharge and bioavailability of heavy metals.  相似文献   

18.
This study was designed to investigate heavy metal (Tl, Pb, Cu, Zn, and Ni) contamination levels of arable soils and vegetables grown in the vicinity of a sulfuric acid factory in the Western Guangdong Province, China. Health risks associated with these metals by consumption of vegetables were assessed based on the hazard quotient (HQ). The soils show a most significant contamination of Tl, followed by Pb, Cu, Zn, and Ni. The heavy metal contents (µg/g, dry weight basis) in the edible parts of vegetables range from 5.60 to 105 for Tl, below detection limit to 227 for Pb, 5.0–30.0 for Cu, 10.0–82.9 for Zn, and 0.50–26.0 for Ni, mostly exceeding the proposed maximum permissible level in Germany or China. For the studied vegetables, the subterranean part generally bears higher contents of Tl and Zn than the aerial part, while the former has lower contents of Cu and Ni than the latter. In addition, the results reveal that Tl is the major risk contributor for the local people since its HQ values are mostly much higher than 1.0. The potential health risk of Tl pollution in the food chain and the issue of food safety should be highly concerned and kept under continued surveillance and control.  相似文献   

19.
Freshwater lakes are one of the most vulnerable ecosystems to environmental contamination. This study was initiated to assess the spatial distribution, fractionation, ecological risk of selected potentially toxic metals (Pb, Zn, Cu, Cr, and Ni) in bottom sediments of the Zarivar lake, the second largest freshwater lake in Iran. The results revealed that Pb, Zn and Cu had the high spatial variability (coefficient of variation >50) across the sampling sites and their maximum concentrations (197.5 for Pb, 198.7 for Zn and 185.6 mg/kg for Cu) were observed in sampling sites from the northern, western and eastern margins of the lake. Cr and Ni with average concentrations of 28.3 and 31.38 mg/kg respectively, exhibited low spatial variability (coefficient of variation <20) and their concentrations did not vary significantly among the sampling sites. Based on the redundancy analysis (RDA), sediment organic matter was strongly correlated with Pb, Zn and Cu while Fe2O3 and Al2O3 showed a positive correlation with Ni and Cr. The calculated average enrichment factor (EF) and geoaccumulation index (Igeo) showed that the contamination level of metals can be arranged in the following order of Pb> Cu > Zn > Cr > Ni. Results from the modified five-step sequential extraction analysis indicated that 40 % of total Pb and Zn were associated with the reducible fraction, 45 % of Cu with the oxidizable fraction and more than 80 % of total Ni and Cr were retrieved from the residual fraction. It was also noticed that Pb, Zn and Cu were more incorporated into the non-residual fractions in the sites with a higher total concentration of these metals, suggesting that both total concentration and fractionation behavior of metals were influenced by their potential sources in the study area. Ecological risk assessment using the potential ecological risk index (PERI) and the modified potential ecological risk index (MPERI) showed that sediments from the eight sampling sites pose a moderate to considerable risk whereas the other sites had low ecological risk level. In comparison to sediment quality guidelines (SQGs), the effects range low (ERL) and probable effect level (PEL) values for Pb, Cu and Zn were exceeded at some sampling sites while Ni and Cr concentrations were found to be below or close to their SQGs values at all the sampling sites. Pb was generally identified as the contaminant of most concern in the study area. Taking into account the results obtained from the fractionation study and the source contribution estimate, it can be inferred that the Pb, Zn and Cu with the average contribution of 79, 54 and 64 % respectively, were mainly derived from anthropogenic sources whereas Ni and Cr with the estimated contribution of 80 and 89 % were predominately from the lithogenic source.  相似文献   

20.
Surface soils (0–20 cm) were collected from along a tidal ditch of the Yellow River Estuary in August of 2007. Samples were subjected to a total digestion technique before they were analyzed for total concentrations of As, Cr, Cd, Cu, Ni, Pb, Zn, P and S in order to investigate heavy metal contamination levels in wetland soils nearby the tidal ditches and their main sources. Results showed that the mean concentrations of these heavy metals except for As and Cd were lower than the Class I criteria. Nearly all sampling sites showed lower contamination levels for As and Cd, while no contamination levels for other heavy metals. Cr, Cu, and Ni mainly originated from parent rocks, and Pb and As might originate from tidal seawater and oil field pollution, respectively; while Cd and Zn mainly originated from parent rocks and tidal seawater. Most of heavy metals showed significant correlations with total concentrations of P and S, however, no significant correlations were observed between them and soil pH, slat and soil organic matter.  相似文献   

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