Concentrations and chemical forms of potentially toxic metals in road-deposited sediments from di erent zones of Hangzhou, China

The 25 road-deposited sediments were collected from five di erent land-use zones (industrial, residential, commercial, park, and countryside) in Hangzhou, China. The concentrations of metals (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) in these samples were determined using ICP-AES after digestion with the mixture of HNO3-HF-HCl (aqua regia), and chemically fractionated according to the modified BCR (the European Community Bureau of Reference) sequential extraction procedure. The high metal concentration levels were detected in the sample from industrial zone and commercial zone having heavy tra c. While the low metal levels were noted in the street dust sample from residential zone, park, and countryside zone. The mobility sequence based on the sum of the BCR sequential extraction stages was: Zn (80.28%), Pb (78.68%), Cd (77.66%) > Cu (73.34%) > Mn (67.92%) > Co (41.66%) > Ni (30.36%) > Cr (21.56%), Fe (20.86%). Correlation analysis and principal component analysis were applied to the data matrix to evaluate the analytical results and to identify the possible pollution sources of metals. Factor analysis showed that these areas were mainly contaminated by three sources, namely lithology, tra c, and industry.     

湘江表层沉积物重金属的赋存形态及其环境影响因子分析

采用BCR三步分级提取法分析了湘江衡阳段与岳阳段表层沉积物中4种重金属（Cd、Pb、Cu、Zn）不同赋存形态的含量,阐述了重金属赋存形态及其环境影响因子的关系,评估了这4种重金属的生物有效性.结果表明,4种元素均以弱酸溶解态、可还原态和可氧化态3种可提取态为主,各元素生物有效性即可提取态含量排序为：Cd〉Pb〉Zn〉C...     

Risk assessment and binding mechanisms of potentially toxic metals in sediments from different water levels in a coastal wetland

The excessive accumulation of potentially toxic metals (Pb and Cd) in coastal wetlands is among the main factors threatening wetland ecosystems. However, the effects of water table depth (WTD) on the risk and binding mechanisms of potentially toxic metals in sediments remain unclear. Here, sediments from different WTD obtained from a typical coastal wetland were evaluated using a newly developed strategy based on chemical extraction methods coupled with high-resolution spectroscopy. Our findings indicated that the WTD of the coastal wetland fluctuates frequently and the average enrichment factor for Pb was categorized as minor, whereas Cd enrichment was categorized as moderate. High-resolution spectroscopy techniques also demonstrated that organic functional groups and partly inorganic compounds (e.g., Fe-O/Si-O) played a vital role in the binding of Pb and Cd to surface sediments. Additionally, mineral components rather than organic groups were mainly bound to these metals in the bottom sediments. Collectively, our findings provide key insights into the potential health effects and binding characteristics of potentially toxic metals in sediments, as well as their dynamic behavior under varying sediment depths at a microscale.     

湖北网湖沉积物重金属分布特征、源解析及风险评价

为揭示湖北网湖沉积物重金属污染特征,采用空间插值法、主成分分析法和地累积指数对其污染特征、来源识别及生态风险状况进行分析。结果表明：5种重金属的平均浓度从高到低依次为Zn>Cr>Cu>Pb>Cd,且浓度均超过湖北省土壤背景值;Pearson相关性分析表明,Zn与Cd、Pb浓度呈正相关（P<0.05),Cu与Zn、Cr浓度呈负相关（P<0.05)。主成分分析发现,主成分1由Pb、Cd、Zn构成,主要来源于河流运输和农业活动影响;主成分2由Cr和Cu构成,主要来源于矿物风化等自然背景和工业活动及水产养殖等人类活动污染影响。地累积指数结果显示,网湖沉积物中重金属处于低风险状态,但Cd和Cu达到中度污染,为主要污染物,应予以关注。

     

滇池内湖滨带沉积物中重金属形态分析

采用BCR3步分级提取法测定了滇池内湖滨带沉积物中4种重金属(Pb、Cd、Cu和Zn)不同形态的含量,初步评估了这4种重金属的生物有效性.结果表明,Cd和Zn主要以可提取态存在(即弱酸溶解态、可还原态和可氧化态),而Pb和Cu均以残渣态为主要存在形式.通过计算可提取态含量所占总量百分量大小,可知各金属的生物有效性大小排序为:Zn(53.06%)>Cd(50.84%)>Cu(34.62%)> Pb(28.65%).沉积物中总有机碳(TOC)与各金属不同形态间的相关性分析表明,可氧化态重金属与有机碳结合的趋势远大于弱酸溶解态和可还原态.表层沉积物中可提取态重金属的空间分布特征明显表现为草海>外海,除Cu外,大部分样点的可提取态Pb、Cd和Zn含量均随采样深度增加而减少.     

城市污泥好氧堆肥过程中重金属的形态变化

污泥中重金属的含量和各重金属的生物有效性是污泥农业利用的重要限制因素.本研究对城市污泥进行了堆肥化处理,并采集不同阶段样品,通过顺序浸提法对样品中不同形态的重金属进行提取,分别利用原子吸收分光光度计测定Zn、Cu、Ni、Pb、Cd含量、分光光度法测定Cr和As含量.研究结果发现,与现有国际及我国污泥农用标准比较,所研究污泥中重金属含量均未超过允许的水平.污泥堆肥中Cu、Ni、Cd、Cr主要以残渣态形式存在,Cu、Ni、Pb、Cd四种重金属元素的可氧化态含量也相对较高,除Cd外,经过堆肥化处理后所有重金属的有效态含量均呈下降趋势,因此,堆肥可以促进污泥中的重金属稳定化,降低土壤的污染风险.     

Heavy metals partitioning in the sediments of Izmir Inner Bay

Izmir Bay is known to be polluted by high concentrations of heavy metals and organic pollutants.Sediment samples taken from 7 different stations in Izmir Inner Bay were analyzed for their total organic matter content and,Cu,Cr Pb and Zn.In addition,the chemical distribution of the metals were determined by means of the BCR(Community Bureau of Reference)Extraction Procedure (developed by European Commission for Standards,Measurement and Testing) which allows the determination of metals bound as four fractions;exchangeable and acid soluble,reducible(bound to iron-manganese oxides),oxidizable(bound to organics)and residual.The results show that Izmir Inner Bay contains sediments with high metal concentrations.According to the chemical distribution of metals,Cr and Cu tend to accumulate mostly on the organic fraction of the sediment.Pb is mostly found in the reducible fraction where Zn is mobile in the sediment,and it is distributed evenly on each fraction.     

Fractionation of heavy metals in shallow marine sediments from Jinzhou Bay, China

This work investigated the distribution and speciation of Cd, Cu, Pb, Fe and Mn in the shallow sediments of Jinzhou Bay, Northeast China, which has been heavily contaminated by nonferrous smelting activities. The concentrations of Cd, Cu and Pb in sediments were found to be 100, 13 and 7 times, respectively, being higher than the national guideline (GB 18668-2002). Sequential extraction test showed that 39%-61% of Cd were exchangeable fractions, indicating that Cd in the sediments posed a high risk to local...     

Characterizing spatial distribution and sources of heavy metals in the soils from mining-smelting activities in Shuikoushan, Hunan Province, China

The spatial variation of heavy metals in the soils in Shuikoushan mining-smelting area, Hunan Province, China, was investigated using multivariate and geo-statistic analysis. A total of 106 composite soil samples were collected in an area of about 100 km2. Concentrations of total As, Cd, Pb, Zn, Cu and Cr were measured using inductively coupled plasma mass spectrometry (ICP-MS). Arsenic and Pb were found to have a common source, indicating the same sources and spreading processes, such as aerosols and airborne particulates from smelting chimneys. Airborne sources from smelting chimneys contributed greatly to Cd in the area, which demonstrated the same dispersion pattern as As and Pb. However, two hot spots of Cd around smelters were possibly enlarged by wastewaters, demonstrating another important source of Cd in Shuikouhsan. Geo-statistic interpolated mapping demonstrated that hotspots of Zn were only found proximal to the large smelters, suggesting that Zn primarily came from the chimneys of larger smelters. The major Cu hot-spots appeared closely to the tailing dam, indicating that weathering and leaching of tailings were the major sources of Cu contamination in Shuikoushan. Our findings indicated that airborne volatile particles and aerosols contributed the most to As, Cd, Pb, Zn and Cu contamination, while Cd and Cu may also derive from the discharge of wastewater from smelters and the leaching of tailings, respectively.     

Pollution characteristics of the recent sediments in the Hangzhou section of the Grand Canal, China

Spatial distribution of heavy metals, arsenic and organic matter in recent sediments in the Hangzhou section of the Grand Canal and their relationships were analyzed. The results showed that the concentrations of heavy metals and organic matters varied widely along the canal, and the average geological accumulation factors decreased in the following orders: organic carbon(2.6), zinc(2.1 ), cadmium(2.0), copper( 1.5), lead(1.1), nitrogen(0.9), mercury (0.8), phosphorus(0.4), arsenic(0.2) and chromium(0). Content of heavy metals and organic carbon in the top 10 cm layer were lower than that of lower layers, except for mercury and organic carbon in the S9 section. Contents of organic carbon in the top 50 cm layer of the mud sediments are significantly higher than those undemeath. In the bottom mud layer, there is a concentration peak of the pollutants. In the mud sediments of the canal, cadmium mainly occurred in the Fe and Mn oxide fraction, copper in the organic fraction, lead in the Fe and Mn oxide fraction, and zinc in the carbonate and the Fe and Mn oxide fraction.     

Semivolatile organic compounds, organochlorine pesticides and heavy metals in sediments and risk assessment in Huaihe River of China

The concentrations of semivolatile organic compounds, organochlorine pesticides and heavy metals in sediments from Jiangsu reach of Huaihe River, China, were presented. The organic compounds were extracted by acetone： n-hexane using a Soxhlet apparatus and concentrations were performed using HP6890 gas chromatography coupled by FID and ECD detector. The total contents of 8 heavy metals by inductively coupled plasma atomic emission spectrometry or cold-vapor/atomic absorption spectrometry were developed. 30 semivolatile organic compounds were detected, including substituted benzenes, phenols, phthalates and polycyclic aromatic hydrocarbons, from 0.01 to 3.01 mg/kg. 16 organochlorine pesticides were almost detected and from 0.010 to 2.339 μg/kg. Concentrations of major metals were 50 mg/kg or less, mean level of mercury was only 0.055 mg/kg. Compared to sediment quality guidelines （SQGs）, concentrations of some semivolatilc organic compounds were high enough to cause possible toxic effects to living resources. The organochlorine pesticides presented relatively low, lower than threshold effect concentrations （TECs）, harmful effects on sediment-dwelling organisms were not expected. Chromium posed probable toxic effects to the living resources, other heavy metals had no threat temporarily according to SQGs.     

香港汀角红树植物、沉积物及双壳类动物重金属含量

汀角有香港面积最大的硬底质红树林,作者调查了该红树林区沉积物、红树植物以及双壳类动物体内重金属(Cu、Pb、Zn和Ni)的含量.总体看,沉积物中重金属含量与其他地点相比较低,红树植物根际沉积物中重金属含量高于光滩.红树植物组织内重金属含量较低,体内Pb、Zn的含量均低于根际沉积物,但对Cu、Ni有一定的富集,Cu可在根部和叶内富集,而Ni只在根部富集,并束缚于此.双壳类动物对4种重金属的吸收存在较大差异,Zn、Cu的富集明显高于Pb和Ni的富集程度.5种动物中又以岩蠔最高,体内的Zn、Cu分别达到3913, 378mg/g.从重金属含量看,作为食用动物有一定的风险.     

南黄海南部海域表层沉积物重金属来源解析及风险评价

基于2012年夏季对南黄海南部海域的调查资料,分析了表层沉积物中7种重金属元素的含量分布特征;采用多元统计分析,揭示了研究区表层沉积物重金属污染的主要来源及各元素之间的相关性;应用地质累积指数法和Hakanson潜在生态风险指数法对重金属元素进行了污染及风险分析.结果表明:Cd、Pb的含量均符合国标规定的一类沉积物标准,Zn、Cu、Cr在绝大部分站位也都低于国标规定的一类沉积物的最高标准,仅在个别站位处达到二类或三类沉积物标准;除Cr、Cd、Mn外,其余各重金属与Al2O3、平均粒径之间有显著的相关性,表明它们均以自然来源为主,并受到沉积物粒度的控制,遵循"元素的粒度控制律";Cr、Cd、Mn与Al2O3的相关系数较小,表明其可能受到人为污染源的影响.通过主成分分析和聚类分析可将7种重金属元素辨识为2个主成分,PC1(Zn、Cu、Pb、Fe、Mn)为自然源因子,PC2(Cr、Cd)为工农业源因子;其中,Cr、Cd在PC1和PC2上均具有一定的正载荷,受自然地质背景和人类活动的共同控制.地质累积指数法评价结果表明,Zn、Cu、Cd、Pb整体均处于清洁级别,而Cr则处于轻微污染水平,污染程度排序依次为CrPbCdZnCu;潜在生态风险评价结果表明,各元素潜在生态危害等级排序依次为CdPbCuCrZn,Cr、Zn、Cu和Pb均为低生态危害等级,Cd以低中等生态危害等级为主,局部出现较重生态危害等级,综合潜在生态风险评价为低度.     

Changes of Cu, Zn, and Ni chemical speciation in sewage sludge co-composted with sodium sulfide and lime

A batch composting study was performed to evaluate the feasibility of co-composting sewage sludge with sodium sulfide and lime （SSL） mixture （Na2S/CaO= 1：1）, aiming at reducing the availability of heavy metals in the sludge compost. Sewage sludge with sawdust as a bulking agent was amended with SSL at 3% （w/w, dw）, and composted for 15 d in laboratory batch reactors. The four stages of the Tessier sequential extraction method was employed to investigate changes in heavy metal fractions of Cu, Zn, and Ni in sewage sludge composted with SSL. For all the three metals, the mobile fractions, such as, exchangeable and carbonate bound were mainly transformed into low availability fractions （organic matter and sulfide, Fe-Mn oxides bound and residual forms）, and the addition of SSL enhanced this transformation. Therefore, SSL is a suitable material to co-compost with sewage sludge to reduce the availability of heavy metals. According to the cabbage seed germination test, a SSL amendment of ≤3% （w/w, dw） is recommended to co-compost with sewage sludge.     

陆浑水库沉积物重金属空间分布特征及风险评价

为了解洛阳市饮用水水源地陆浑水库沉积物中重金属污染程度,采集32个点位的表层沉积物,分析6种重金属（Cd、Cr、Cu、Ni、Pb和Zn）的空间分布特征,并运用地累积指数法、潜在生态风险指数和聚类分析等方法对研究区重金属污染程度进行评价、生态风险评价及源解析.结果表明：Cd、Cu、Pb和Zn含量超过黄河流域河南段重金属土壤背景值,分别是其8.8、2.0、6.5、2.3倍,重金属存在明显富集,且主要污染集中于坝前区域.地累积指数法评价结果显示,Cd为强污染,Pb为中-强污染.潜在生态风险指数表明,陆浑水库沉积物重金属风险呈自上游至下游逐渐增强的趋势,总体处于高度生态危害,潜在生态风险指数均值达到312.94,其中Cd为主要贡献因子.富集系数法和聚类分析结果显示：Cd、Cu、Pb和Zn主要为人为源,Cr和Pb以自然源为主.总体而言,陆浑水库沉积物中重金属Cd和Pb污染相对较重,可能会对水库水环境构成威胁.     

杭州市河道底泥重金属污染评价与环保疏浚深度研究

重金属是河道底泥疏浚要控制的重要污染物,而疏浚深度是生态疏浚工程中需要确定的关键参数.本文以杭州经济技术开发区河道为研究对象,共采集18处底泥柱状样,采用土壤背景值、土壤环境质量二级标准值、变异系数和相关性分析方法对底泥中Cu、Zn、Pb、Cd、Ni、As的污染状况进行了评价,同时分析重金属总量和有效态含量在垂向上的变化特征,并引入地累积指数法对各深度底泥中的重金属进行累积性评估,利用本文提出的临界累积深度方法来确定合理的环保疏浚深度.结果表明,河道表层底泥中Cu、Zn、Pb、Cd、Ni、As的平均含量分别为165.16、342.40、55.34、3.61、34.06、36.70 mg·kg-1,Cd、Cu、As、Zn的有效态含量分别为0.007、3.37、0.095、20.76 mg·kg-1,重金属总量均超过了杭嘉湖平原土壤背景值,其中Cd污染最为严重.各重金属元素在底泥中的变异系数为0.29~2.39,空间分布并不均匀.重金属总量和有效态含量随底泥深度的增大整体呈下降趋势,但受不同时期人类活动污染及河道整治影响而呈不规则变化.各重金属元素的富集程度为CdAsZnPbNiCu,其中,Cd污染等级为2~6级,污染程度为中度污染至极强污染.利用临界累积深度方法推算得到研究区域河道底泥环保疏浚深度为0~0.9 m.     

锦州湾沉积物中重金属污染的潜在生物毒性风险评价

选择污染严重的锦州湾表层沉积物作为研究对象,运用2套由生物效应数据库法导出的沉积物质量基准(ERL/ERM和TEL/PEL)评价了锦州湾沉积物中重金属的生物毒性风险.同时与地累积指数对重金属污染的评价结果进行了比较.结果表明,潜在生物毒性风险评价和重金属污染评价所反映的结果相一致,可以相互补充和借鉴.基于生态效应数据库法的沉积物质量基准可以有效的评价重金属潜在生物毒性风险.     

Potential toxic risk of heavy metals from sediment of the Pearl River in South China

Based on the monitoring of five heavy metal elements in the surface sediments of the Pearl River in South China, potential toxicity of the heavy metals was assessed using consensus-based sediment quality guidelines (SQGs) method and geo-accumulation (I_geo) index method. The monitoring results showed the heavy metal concentrations were significantly and positively correlated with each other, demonstrating a common trend in variation of concentration in the surface sediments. The assessment using the consensus-based SQGs method showed the potential toxicity of Cu was the highest, and Cd was the lowest. The evaluation based on mean probable effect concentration (PEC) quotient showed the region was seriously polluted with high toxicity heavy metals. Correlation analysis revealed a significant and positive correlation between the mean PEC quotient and the average of I_geo with a correlation coefficient of 0.926 (n = 23, P < 0.01). In conclusion, the consensus-based SQGs and mean PEC quotient are applicable to assess potential toxicity risks of heavy metals in freshwater sediments in the Pearl River.     

贵州草海沉积物重金属元素分布特征及健康风险评价

为研究贵州威宁草海重金属污染现状,对该区域内20个采样点表层沉积物中的6种重金属元素(Pb、Cd、Cu、Zn、Fe、Mn)进行检测和分析.结果表明,表层沉积物中Cd、Zn和Pb的含量分别为贵州省土壤背景值的32.44、614.45和185.30倍,主要来源为采矿及矿物加工.此外,县城污水排放对Cu分布有一定的影响.Cd...     

环巢湖流域表层沉积物重金属赋存特征及潜在生态风险评价

以环巢湖流域表层沉积物为对象,对8种重金属(Cd、Cr、Cu、Zn、Ni、Pb、As和Hg)总量及形态进行分析并运用潜在风险指数法对重金属的生态风险进行了评价.结果表明,环巢湖流域表层沉积物中重金属元素Cd、Cr、Ni、Cu、Zn、Pb、As和Hg的总量总体呈现为南淝河-十五里河水系含量高,其次是裕溪河及支流,其他5条水系的重金属含量相对较低. BCR形态分析表明,重金属元素Hg、Cr、Ni和Cu主要以残渣态存在(分别占总量的77.56%、64.83%、56.52%和48.93%),Cd的可提取态含量比例最高(89.22%),其次为Zn、Pb和As(70.35%,69.50%和63.70%). 潜在生态风险危害指数(RI)表明,Cu、Zn、Pb、Cr、Ni和As均为低污染等级,Cd为较重污染等级,Hg为重污染等级,7个水系的重金属潜在生态风险指数排序为:南淝河-十五里河>裕溪河>柘皋河>杭埠河-丰乐河>派河>白石山河>兆河,重潜在风险和严重潜在风险的区域主要分布在南淝河-十五里河水系以及裕溪河水系,因此,今后对巢湖流域进行重金属整治时可着重考虑针对这两条水系的Cd和Hg元素的重点治理.