泗河表层沉积物重金属形态分布特征及风险分析

采用改进的Tessier连续提取法分析泗河干流及支流7个采样点表层沉积物中的汞、砷、镉、铅、铬、镍、铜、锌和锰共9种重金属不同赋存形态含量,阐述不同重金属的形态分布特征,并运用污染因子法(Cfi)和风险评价指数法(RAC)对重金属的环境风险进行定量评价。结果表明,泗河表层沉积物中汞、镉和锰的平均含量均高于环境背景值,表现出明显的累积效应。沉积物中铬和镍以残渣态为主,除残渣态外,镉、锰和铜可提取态比例较高,铁锰氧化物结合态铅比例较大,汞则以腐殖酸结合态为主,而砷和锌的铁锰氧化物结合态及腐殖酸结合态均占有一定比例。重金属在沉积物中滞留时间由长至短依次为;铬＞镍＞锌＞铅＞砷＞铜＞汞＞锰＞镉。镉、锰和汞在沉积物中滞留时间较短。各种重金属RAC值依次为：镉＞锰＞铜＞锌＞铅＞汞＞砷＞镍＞铬。镉和锰表现出高风险水平,铜为中等风险水平,而汞、砷、铅、铬、镍和锌除了个别点位为中等风险外,大多为低风险水平。     

泉州市主要工业区土壤重金属健康风险评价

为了解泉州市工业区土壤重金属的污染程度,采用现场采样及室内测试方法对泉州市主要工业区土壤中Cd、As、Pb、Zn、Cu、Hg、Ni和Cr等重金属的含量进行测定分析,应用健康风险评价模型对这些工业区土壤重金属通过皮肤暴露途径所引起的健康风险作出评价.结果表明,工业区土壤已受到不同程度的重金属污染,其中以Zn、Cu、Pb污染最为严重.土壤重金属的含量空间分布并不均匀.土壤重金属非致病风险大小为:Pb＞ As＞ Cu＞ Cr＞ Cd＞ Zn＞ Hg＞ Ni,均小于致癌风险阚值1,对人体不会造成健康危害.致癌风险Cd＞ As,均低于致癌风险阈值,表明Cd和As不是主要的致癌风险因素.     

柿竹园矿区及周边农田土壤重金属形态分布与生物有效性研究

为了解柿竹园矿区及周边农田土壤重金属的生物有效性,采用连续提取法对该矿区及周边的农田土壤重金属Cu、Pb、Zn、Cd、As、Hg的形态分布和生物有效性进行了分析。结果表明:(1)柿竹园矿区及周边农田土壤未见Hg污染情况,但不同程度受到Cu、Pb、Zn、Cd、As的污染,尤以Cd、As污染为重;(2)柿竹园矿区及周边农田土壤中Cu、Pb、Zn以铁锰氧化物结合态为主,分别占其总量的48.3%、67.3%、47.1%,Cd铁锰氧化物结合态含量最高,残渣态、离子交换态和碳酸盐结合态次之;As和Hg以残渣态为主,含量比例在90%以上;(3)矿区及周边土壤中Cd的有效态含量最高,所占比例平均值为31.1%,远高于其他5种重金属元素,生物有效性最高,As的有效态含量最低,生物有效性最低。最后提出了采用稳定化修复技术清理污染源、采用磷酸二氢钙降低土壤中污染最严重元素Pb、Cd的生物有效性、采用香蒲等植物对工矿废弃地及部分未利用土地进行修复的建议。     

武汉市侏儒—消泗一带土壤形态分布研究

以武汉市侏儒—消泗地区土壤为对象,研究该区土壤形态样品中Se、Cd、As、Cu、Zn、Hg、Pb等7个元素的全量和7种形态分布及其生物有效性,研究对比各元素的各形态特征并总结其活性规律。结果表明,土壤中As、Cu、Zn、Hg、Pb、Se主要以残渣态存在,As、Cu、Zn、Hg残渣态占比均达60%以上,可交换态的比例很低。Cd主要以易利用态存在,且Cd的可交换态比例最高,活性最强。Se水溶态和腐殖酸结合态比率比重金属还高,Se相对容易被植物吸收。同时对Se、Cd在不同土壤类型中的各形态进行分析,结果表明二者的形态受土壤类型影响较大,可为改良富硒重镉土壤的p H和提高土壤硒的有效利用性提供一定依据。     

赣南某矿区土壤重金属污染评价与研究

这是一篇矿山环境工程领域的论文。对赣南某矿区40个土壤样品的重金属含量进行了测定,结果显示,Cu、Zn、Cr、Ni、Cd、As和Hg含量的平均值均低于江西省土壤重金属背景值,而Pb含量高于背景值。相关性分析结果表明,研究区内土壤重金属Cu和Cr、Ni、Cd,Zn和Cd,Ni和Cr、Cd,Hg和As呈现显著正相关,说明其可能具有较高的同源性或复合关系。分别利用单因子污染指数法、Nemerow综合污染指数法、污染负荷指数法和潜在生态风险分析法对研究区内土壤污染程度进行了评价和风险评估。单因子污染指数法评价结果表明,单一元素污染程度由高到低依次是Pb>Cd>Zn,但总体污染程度较低;Nemerow综合污染指数指出重金属重度污染的样本点主要集中在矿区和河流中下游地区;土壤样本重金属污染系数均值从高到低依次是Pb、Cd、Zn、Cr、Cu、Hg、Ni和As,整个研究区内土壤污染负荷指数适中,污染水平中等;重金属Cu、Zn、Cr、Ni和As的潜在生态风险评价属于轻微生态风险,而Cd、Hg、Pb在研究区土壤生态环境中的贡献率较高。综合四种方法可知,整个研究区土壤重金属的综合潜在生态风险处于...     

煤矿周边土壤重金属形态特征及迁移转化规律

为了研究煤矿周边土壤内重金属形态特征以及迁移转化规律,采用Tessier五步连续提取法分析了矿区周边土壤内重金属形态特征,研究了重金属迁移和释放规律以及重金属分布状况。结果表明:(1)土壤内Cd主要以有机物结合态和铁锰氧化结合态存于土壤中,Cu主要以碳酸盐结合态和残渣态留存在于土壤中,Pb、Zn主要以可交换态和碳酸盐结合态存在于土壤中。Pb、Zn、Cu生物有效利用率较高。(2)重金属的释放速率受酸碱性影响明显,酸性条件会加快重金属的释放并促进Pb、Zn、Cu、Cd在土壤与水体之间交换、迁移。(3)重金属Pb、Zn主要分布在表层,煤矿开采对土壤内重金属Pb、Zn含量影响较大,对Cu、Cd影响小。     

清水塘土壤中重金属含量空间分布特征

通过对清水塘区土壤的研究,讨论土壤纵面重金属的分布特征。结果表明：该地区Zn、Cu、Pb、Cd、As、Rb、Co、Ni、Cr、Hg等的重金属含量平均值均高于全国土壤元素背景值。Zn、Pb、Cd、As等元素平均含量明显偏高。大多数重金属含量随土层的加深呈下降趋势,土壤各层重金属变异系数波动范围较大,位于冶炼厂附近的土壤剖面采样点,其重金属含量平均值明显高于其他采样点。土壤中的Zn和Cu、Pb和Zn,Zn和Hg,Pb和Hg,Rb和Cd有正相关关系(p<0.01),Cu和Sr,Pb和Sb,Sr和Cr之间具有一定的负相关关系。     

湖北省红安县基于生态地质单元的土壤重金属分布规律对比研究

为探索生态地质单元对土壤重金属分布规律的控制作用，参考生态地质单元三级分区标准，在红安县划分出8个生态地质单元，筛选金沙湖长英质变质岩缓丘陵(JSH)、永佳河基性—超基性岩低丘陵(YJH)和觅儿寺第四系缓丘陵(MES)3个重点生态地质单元，系统采集740件表层土壤样，开展8种重金属(As、Cd、Cr、Cu、Hg、Ni、Pb、Zn)分布特征及来源的对比分析。研究表明，不同生态地质单元内土壤重金属含量的数理统计特征差异较大，YJH生态地质单元土壤的As、Cr、Cu、Ni、Zn, MES生态地质单元土壤的Cd、Hg、Pb的平均含量和中位数相对较高；JSH、YJH、MES生态地质单元土壤的超标重金属分别为Cd、Cr、Ni, Cd、Cr、Cu、Ni、Zn, As、Cd、Cr、Cu、Ni、Pb、Zn,并分别表现出存在少量Cd、Cr、Ni轻微污染，以Cd、Cu、Ni轻微污染为主，以Cd、Cr、Cu、Ni轻微污染为主的特征。综合超标重金属空间分布特征及主成分分析结果，认为不同生态地质单元土壤中重金属的来源不同，YJH和JSH生态地质单元土壤的Cr、Cu、Ni可能主要来源于自然界的基性—超基性岩及萤石矿...     

皖北煤矿区农田土壤-小麦中重金属分布特征 及健康风险评价

为了研究矿区农田土壤-小麦中重金属分布及农作物中重金属的迁移特征,以皖北恒源煤矿为研究对象,在矿区范围内采集了16个农田土壤和对应的小麦样品进行测试分析,应用内梅罗指数法评价了矿区内农田土壤重金属的污染状况,采用回归模型分析研究土壤根系、根系茎籽粒中重金属的迁移转化,并利用靶标危害系数法评价了小麦籽粒中重金属对人身健康的影响。研究结果表明:研究区农田土壤中的Cu、Zn、Mn、Pb、Hg、Cd、As、Cr和Ni等8种重金属元素含量低;小麦籽粒中重金属含量也未超出标准限量值;在小麦根、茎、籽粒等器官中,Mn、Pb、Cd、As、Cr和Ni在小麦根部含量最大,Hg较多地分布在小麦的茎中,Zn和Cu更易向上迁移至小麦的籽粒中;小麦籽粒中的Pb、Hg、Cd、As和Cr等重金属的单一重金属元素的靶标危害系数THQ和多种重金属元素的复合危害系数TTHQ均小于1。     

准能公司污水厂外排污泥重金属形态赋存特征及环境风险

对神华准格尔能源公司污水处理厂外排污泥进行扫描电镜及X-射线能谱分析,表明污泥颗粒具有形状不规则,大小分布不均匀,表面有明显褶皱等特点,C、O、Na三种元素含量最高。利用电感耦合等离子体质谱仪(ICP-MS)对外排污泥中重金属含量进行分析,重金属含量大小顺序为MnZnCuCrNiAsPbCd,含量依次为945.07mg/kg、477.04mg/kg、96.99mg/kg、84.57mg/kg、84.4mg/kg、45.04mg/kg、40.85mg/kg、0.34mg/kg,其中Cr、Ni、Zn、Pb、Mn主要以残渣态存在,Cu和As主要以可氧化态为主。地累积指数法(Igeo)评价表明Zn具有偏重的环境风险,Ni、Cu、As可能造成中度的环境污染,Pb、Mn、Cd可能造成轻微的环境污染;潜在生态危害指数法(RI)评价表明Cd具有较高的潜在生态风险,需要引起注意。     

Current situation and future trend of China rare earth luminescent materialindustry(continued)

<正>Developing ecological lighting source The world is facing the big problem of energy shortage today and the contradiction between economy development and environmental protection is worsened.Therefore,people are more likely to choose an ecological light source that is more energy efficient and environmental friendly.The choice provides great opportunity for the development of rare earth optical material industry in China.The concept of green lighting positions rare earth luminescent material as a leading player in illumination market.The light source of both rare earth luminescent lamp and LED lamp is ecological and energy saving.This is why     

Galaxy Magnets achieved the net profit of 34.02 million yuan in the first six months of 2014

正Galaxy Magnet announced its financial results for the first half of 2014 on August 14.For the first six months ended on 30 June 2014,Galaxy Magnet achieved operation income of RMB 182.3 million,up8.40% over the same period of 2013,and the net profit attributable to the shareholders of the listed company of 34.02 million yuan,increasing 35.49% over the same period of last year.Stable performance increase was led by development of new customers and application market of magnets.     

Rare Earth Application in Steel in China

<正>China has rich rare earth resources.Output of rare earth and steel in China ranks the top first in the world.However,there is still certain distance between the steel produced in China and developed countries from the point of varieties and quality.China still has to import some types of steel.Improving the quality should be emphasiZed in future development of steel industry in China.Rare earth can be used to upgrade traditional steel     

China rare earth market review

正November 21~30,2014Due to weak demand from downstream industries,transactions of rare earth in Chinese domestic market were inactive.It was difficult to sell any rare earth products except for dysprosium oxide and terbium oxide.Suppliers lost confidence in recent market.Demand for rare earth products was soft.Consumers continued to take a wait-and-see attitude.Rare earth export market remained slow.     

稀散金属产业的观察与思考

分析了近年来国内外稀散金属产业的生产、应用、资源与市场状况.铟锡氧化物靶材、砷化镓晶片、锗红外材料、铼高温合金和硒在电解锰及玻璃的应用等已成为稀散金属的主要应用领域.稀散金属的产量快速增长达到历史高位而导致了市场的失衡.以GaInP_2/GaAs/Ge,CIGS和CdTe为代表的非硅系太阳能电池是稀散金属的新兴应用领域,将给稀散金属带来日益增长的需求.     

Current situation and future trend of China rare earth luminescent material industry

<正>Rare earth luminescent material is one of the most important application sectors of rare earths.China enjoys the exceptional advantage to develop rare earth luminescent material for its abundant rare earth resources.After several decades'endeavor,China's rare earth luminescent material industry,headed by rare earth phosphor for lamp and LED and high efficient rare earth energy-saving light source,has been gradually developed into a scale industry.China has become a major production base of rare earth phosphor for lamps and rare earth     

China rare earth market review

正June 1~10,2014Rare earth market remained weak.Quoted price of rare earth products was similar to that in May.There was no sign of recovery in downstream market.The market of NdFeB magnetic materials and phosphor was depressed.Catalyst,polishing powder and ceramic industries remained inactive.Demand from downstream industry was soft.Consumers purchased on their needs.Suppliers had strong intention to sell.Prices of rare earth products     

Annual Report analysis of Chinese rare earth-related listed companies in 2013

<正>Chinese rare earth-related listed companies have published their 2013 annual reports.It can be understood from their reports that production and operation activities of Chinese rare earth-related companies were still heavily affected by macro economy and industrial policies.They basically followed the steps of national economy.In 2013,world economy recovered slowly but the economy     

Market opportunities and challenges for rare earth polishing powder

正1.Status of rare earth polishing powder Rare earth polishing powder with high content of cerium oxide began to replace iron oxide for glass polishing and became one of the key materials in glass polishing process since 1940.Compared with traditional iron oxide,rare earth polishing powder has many advantages,such as fast polishing rate,high polishing quality and long service life.It can achieve good surface quality and improve operation conditions.For example,in lens polishing,the polishing work that cerium     

Baotou Research Institute of Rare Earths developed a new RE alloy preparation technology

正Pyrometallurgy Laboratory of Baotou Research Institute of Rare Earths had independently developed a new preparation technology of rare earth alloy for NdFeB.The alloy can remarkably enhance the coercivity of NdFeB magnet but also evidently reduce the production cost of the magnet.The new master alloy was prepared in the kA pilot-scale electrolytic cell by the independent technology.The rare earth master alloy can be used as the raw material for NdFeB.Compared