宁夏贺兰县土壤重金属分布特征及其生态风险评价

为研究西北地区农田土壤重金属分布特征及其生态风险,以宁夏贺兰县为研究区,采集农田表层土壤样品140个,分析测试了Cr、Ni、Cu、Zn、As、Cd和Pb含量,并采用内梅罗综合污染指数和H?kanson潜在生态风险指数法进行了重金属生态风险评价。结果表明:宁夏贺兰县农田表层土壤Cr、Ni、Cu、Zn、As和Pb元素均低于国家土壤环境二级标准,仅有1.42%样点的Cd元素出现超标;与宁夏土壤背景值相比,各元素都有不同程度的累积,其中Cd和Ni元素超出背景值的点位率分别达到100%和85%;土壤各重金属元素的分布特征较为一致,各元素含量分布比较均匀,高值区集中在中部和东部地区,主要受人类活动的影响。单因子污染指数分析结果表明,Cd元素有0.71%的点位为中度污染水平,Ni和As分别有7.14%和5%的点位处于尚清洁水平,Cr、Cu、Zn、Pb全部清洁,尚未造成污染。重金属的单项生态风险指数(E_r~i)表明,Cd元素的平均潜在生态风险指数为97.68,达强烈风险水平,是最主要的生态风险元素。宁夏贺兰县农田土壤环境质量整体良好,Cd和Ni累积严重,值得关注。     

苏南某冶炼厂周边农田土壤重金属分布及风险评价

选择江苏南部冶炼厂周边污染的水稻田,采集耕层0～15cm的土壤,分析土壤中重金属Cd、Pb、Hg、As、Zn、Cu的污染程度及其空间变异特征。结果表明,土壤Cd、Pb、Cu、Zn、Hg的全量随着距污染源距离的增加而减少,呈现由东北向西南扩散的趋势,As则是由西北向东南扩散。6种重金属中Cd、Hg的污染范围相对较大,Zn的污染范围最小。DTPA浸提的6种重金属有效态含量都是距污染源距离越远而越少。采用内梅罗综合污染指数法对土壤中的重金属进行风险评价,土壤重金属的综合污染指数为39.27,污染程度已超过5级,为重度污染,其中Cd、Hg污染最为严重,含量范围分别为3.98～44.58mg·kg-1、0.36～2.01mg·kg-1,As为中度污染,Pb、Cu、Zn则为轻度污染,说明研究区域农产品安全生产存在很大的风险。     

三峡库区耕地重金属分布特征初步研究

通过对三峡重庆库区16个市、县(区)旱地和水田土样分析、统计、评价,研究了库区耕地土壤主要重金属元素分布特征。结果表明,库区耕地土壤有不同程度污染,重金属As、Cd、Cu、Ni的含量均有超标,Cd有最大超标;旱地土壤重金属含量略高于水田,紫色土略高于黄壤,各采样点重金属含量差异大;重金属元素Cd、Pb、Cu、As、Zn间存在极显著正相关,土壤污染有复合污染趋势;主要淹水区县土壤环境质量评价结果显示,仅巫山县污染综合指数评价为中污染,主城区、开县为轻微污染,涪陵区、长寿区、奉节县为警戒级,其余为安全级;耕地土壤中重金属元素均未超过土壤环境基本容量,能够保证作物品质和农业持续发展。同时对三峡库区耕地重金属淹水和非点源污染进行风险分析,指出库区开展淹水重金属形态与非点源污染输出研究意义.     

某炼钢厂周边农田土壤重金属污染状况的调查与评价

调查了闽西某炼钢厂周边农田土壤的重金属污染状况,以《土壤环境质量标准》(GB 15618—1995)中的二级标准作为评价标准,对土壤重金属Cr、Pb、Cd、Ni、Cu、Zn、As进行了污染指数评价、主成分分析和因子分析,以明确土壤中的主要污染重金属种类及其污染程度、重金属的主要来源和污染分布。单因子评价结果表明调查区土壤Cd和Zn的污染普遍且较严重,点位超标率分别为100%和95.5%;Pb、Cu和As污染程度较轻,点位超标率分别为29.6%、15.9%和6.8%;土壤未遭受Cr与Ni的污染。主成分分析和因子分析法分析结果表明,Pb、Cd、Cu、Zn、As之间相关性显著,具有同源性,主要受炼钢厂排放的污染物影响;而Cr和Ni之间相关性显著,亦具有同源性,主要受土壤本底含量的影响。土壤重金属的综合污染程度随距炼钢厂距离的增加而逐渐递减,炼钢厂污水进入农田的主要进水口附近的农田土壤污染较严重。     

三峡库区典型农业区土壤重金属污染特征及风险评价

为了解三峡库区农业区土壤重金属污染现状及环境风险水平,该文以重庆市8个典型农业区县(铜梁、云阳、万州、丰都、城口、垫江、南川和江津)土壤为研究对象,共采集表层(0~20 cm)土壤样品160个,依照《土壤环境监测技术规范(HJ/T 166-2004)》和《土壤环境质量标准GB 15618-1995》分析了土壤样品中8种重金属(As、Cd、Cr、Cu、Hg、Ni、Pb和Zn)的含量,比较了不同区县8种重金属污染现状及差异,应用地积累指数法和潜在生态风险指数法探讨了研究区土壤重金属的累积特征及潜在生态风险等级。结果表明:该研究区农业土壤8种重金属含量平均值均未超过《土壤环境质量标准GB 15618-1995》二级标准,与土壤背景值相比,Cd、Cr、Cu、Hg和Zn均具有极显著差异(P0.01),As、Ni和Pb差异不显著,8个区县Cr均表现出极显著差异(P0.01),城口区多种重金属均表现出极显著差异(P0.01),8种重金属地累积指数平均值均小于0,研究区土壤受重金属污染水平为未污染等级,单个重金属潜在生态风险顺序为HgCdAsHgCuNiCrZn,Hg元素潜在生态风险指数平均值为43.840,属中等生态风险等级,其余元素生态风险指数值均小于40,属于低生态风险等级,8种重金属综合潜在生态风险指数平均值为108135,为低生态风险等级。综合研究结果表明:三峡库区典型农业区土壤Cd、Cr、Cu、Hg和Zn具有一定程度的累积,且表现为多种重金属复合累积现象,Cr累积具有普遍性,Hg是影响三峡库区农业土壤综合潜在生态风险的主要元素,但研究区土壤重金属总体处于低生态风险水平。     

松嫩平原产油区农田土壤重金属含量及污染风险评价

  目的  为探明松嫩平原石油开采及石化工业活动区周边农田土壤重金属污染分布及风险状况。  方法  在大庆市让胡路区选择代表性农田采集96份土壤样品,测定重金属（Cd、Hg、Ni、Pb、Cu、Zn、Cr、As）含量;在利用地统计学克里金插值法分析重金属含量空间分布特征的基础上,采用地积累指数法和潜在生态危害指数法对该地区农田土壤重金属污染状况及其生态风险进行评价。  结果  该区土壤中Cd和Ni的含量分别为土壤背景值的1.39倍和1.27倍。在对各样点Pb、Zn、Cu和Cr 4种元素含量分析中,均出现不同程度的高于土壤背景值的样点。重金属Cd的地积累指数平均值为0.11,达到轻度~中度污染水平。研究区土壤重金属潜在生态危害风险指数（RI）平均值为84.84,从大到小为Cd > Hg > Ni > As > Pb > Cu > Zn > Cr,其中Cd的RI值最大为190.23,达到中等生态危害范围。研究区农田土壤重金属含量在空间分布上表现为:Cd、Zn和Pb含量高值区出现在中部地区,其它重金属元素含量高值区分布比较零散。  结论  研究区域内,8种重金属含量的平均值均低于风险筛选值,Cd和Ni两种重金属平均含量超出了背景值,从地积累指数来看,Cd污染等级为1级,其它7种元素均处于无污染水平。从潜在生态风险分析可知,该区域污染程度属于轻度生态危害范围。     

基于地球化学基线的内蒙古东来地区土壤重金属污染评价

目前,在中、小尺度上确定环境地球化学基线并准确实现重金属元素的空间分布是研究陆表环境变化过程的基础性工作,仍需深入研究。在野外样品采集、实验室分析及取得内蒙古东来地区土壤重金属数据的基础上,采用标准化法确定了内蒙东来地区的表层土壤中8种重金属元素Cu、Cr、Ni、Pb、Zn、Hg、As、Cd的地球化学基线值,分别以研究区土壤背景值及地球化学基线值为参照,使用地累积指数法和潜在生态污染指数法对研究区土壤质量进行了评价,并对几种重金属元素空间分布特征进行了研究。结果表明,由地累积指数法确定研究区土壤Ni、Zn、Pb、As、Hg、Cd元素达到轻-中度污染水平的样品占比分别为4.9%、3.4%、3.8%、7.9%、6.0%、6.2%,其它元素未达到污染水平;由潜在生态风险指数法评价结果可知,Hg和Cd元素具有较重潜在生态风险,达到较重及以上潜在生态风险等级的样品占比依次为9.1%和2.1%,其它元素风险较低;不同参比值的选取对评价结果有一定的影响,整体看来以地球化学基线值为参比值的评价效果较好于以土壤背景值的评价效果。达到一定污染等级的元素集中分布在东来镇东北部及西部地区,其原因可能与人口分布及通过该区的铁路、公路有关。研究区土壤环境质量总体较好,但个别元素潜在生态风险指数较高,应加强管控及预防重金属污染。     

工业型城乡交错区农业土壤Cu、Zn、Pb和Cd的空间分布及影响因素研究

在江苏省无锡市工业型城乡交错区，选择8km2区域，采集119个土壤样品，对土壤Cu、Zn、Pb,Cd及其有效态含量的空间分布和影响因素进行探讨。结果表明：该区土壤Cu、Zn、Pb、Cd含量和变异系数都明显增加，土壤有效态重金属含量与相应的全量重金属含量具有显著相关性。土壤Cu、Zn、Cd空间变异主要受到工业影响，但由于该区工业类型的多样性和工厂分布的分散性，Cu、Zn、、Cd空间分布模式并不相同。本区土壤Pb的分布与工厂分布的相关性不大，但随与城市距离增加而降低。公路和土地利用与土壤重金属含量的关系表现不明显。该区工业污染对土壤重金属空间变异的影响可能掩盖了公路和土地利用等的影响，建议在城乡交错区合理安排工业布局以控制土壤受重金属污染的范围。     

陕北地区土壤重金属污染特征及生态风险评价

以陕西省靖边县表层土壤（0~20 cm）为研究对象,应用SPSS 19.0软件分析土壤样品中重金属Cr、Cu、Zn、As、Cd、Pb、Hg等7种重金属的含量及来源,运用Hakanson潜在生态危害指数法评价研究区土壤重金属潜在生态危害程度。结果表明,研究区土壤重金属平均含量均低于《土壤环境质量标准》二级标准,各重金属元素变异性较小;相关性分析表明,研究区土壤重金属元素中Cu、Zn、As、Pb两两之间呈极显著的正相关关系;因子分子显示,土壤中重金属的主要来源可能包括研究区附近石油开采活动、交通运输、无机农药和化肥的施用以及工业和居民燃煤等;生态危害评价显示,研究区土壤中仅有Cd元素存在潜在生态风险,其他Cr、Cu、Zn、As、Pb、Hg 6种元素的潜在生态风险均处于低危害水平。     

河南省某铅冶炼厂附近农田土壤重金属污染特征

研究的目的是探讨河南省的铅冶炼企业对附近土壤重金属性质的影响。研究在某年产铅200 000 t以上铅的冶炼厂附近由远及近设置A1和A2两个采样断面(断面中心位置距离冶炼厂烟囱距离分别为2500和1000 m),分析了土壤样品重金属含量。结果表明,A1断面土壤Cd、Cr、Cu、Ni、Pb和Zn的中值分别为4.13、138、20.7、32.7、86.5和66.0 mg kg-1,A2断面以上元素的中值分别为5.75、43.7、22.0、34.0、145和84.7 mg kg-1。研究区土壤Pb的空间分布的均一性较Cd差,Pb的分布受到西南风的影响。土壤Cd、Cu、Pb和Zn含量均随着到冶炼厂烟囱距离的增加而下降,含量和距离间存在显著相关性(P0.05)。各元素的有效性系数(DTPA提取态与全量的比值)以Pb和Cd最大,平均值分别为36.5%和16.8%。以上结果表明,该冶炼厂已经造成了附近农田土壤Pb和Cd的明显积累,且Pb和Cd有较高的有效性。     

有色金属采选冶基地周边土壤中重金属纵向分层研究

土壤中重金属元素的纵向分布特征是土壤自身理化性质和外界环境影响下的综合反映,探寻这个特征对于了解土壤中重金属污染程度和研究修复治理技术意义重大。本研究通过对大型有色金属采选冶企业下风向7种不同土地利用类型的土壤进行纵向采样分析,对重金属元素Zn、Cu、Pb、Cr的纵向分布及累积指数进行了研究,为进一步探寻重金属元素的环境行为及来源,了解重金属污染现状,制定修复方法提供技术参考。研究结果表明:研究区域土壤中重金属含量整体上受到了外源干扰,不同用地类型与不同深度土层重金属含量大小关系不一,证明了不同植被与不同土壤性质对重金属迁移有影响;研究区域重金属整体下移较为活跃,Cr元素表现最为明显;土壤样本中重金属含量均高于内蒙古土壤背景值,重金属元素有不断富集的趋势。     

西北地区金属尾矿地根瘤菌的重金属抗性及其系统发育研究

对分离自陕西、甘肃金属尾矿废弃地寄主为刺槐、鸡眼草、草木樨等23种豆科植物的188株根瘤菌进行了7种重金属的抗性分析、最大抗性水平（MRL）的确定和抗性菌株的系统发育研究。结果表明，菌株之间对重金属的耐受性存在较大差异，大部分菌株表现出对Hg^2＋、Cd^2＋、Cr^6＋（〈0.5 mmol·L^-1）敏感，而对Pb^2＋（〈2.5 mmol·L^-1）不敏感。在液体培养基中，CCNWSX0403和CCNWSX0360可耐受4.0 mmol·L^-1 Zn^2＋，分别可耐受2.4 mmol·L^-1 和2.8 mmol·L^-1 Cu^2＋，CCNWGS0139可耐受0.4 mmol·L^-1 Hg^2＋，CCNWSX0003可耐受2.4 mmol·L^-1 Ni^2＋，CCNWGS0284和CCNWGS0142可耐受4.8 mmol·L^-1 Pb^2＋。9株抗性菌株的16S rDNA全序列分析表明：CCNWGS0122和CCNWSX0003分别属于中慢生根瘤菌属（Mesorhizobium）和中华根瘤菌属（Sinorhizobium）；4株对Pb^2＋、Hg^2＋耐受性较强的菌株CCNWSX0386、CCNWGS0139、CCNWGS0284和CCNWGS0142均属于土壤杆菌属（Agrobacterium）；而属于慢生根瘤菌属（Bradyrhizobium）的3株菌CCNWGS0309、CCNWSX0403和CCNWSX0360对Cu^2＋、Zn^2＋耐受性较好。总体上Agrobacterium对Hg^2＋和Pb^2＋的耐受性较好，Bradyrhizobium比Rhizobium、Sinorhizobium、Mesorhizo     

Heavy Metal Removal in Cold Climate Bioretention

A bioretention media is a stormwater treatment option designed to reduce peak runoff volumes and improve water quality through soil infiltration and plant mitigation. To investigate the heavy metal removal in a bioretention media in a cold climate setting, a small pilot sized bioretention box was built in Trondheim, Norway. The system was sized using the Prince Georges County bioretention design method from 1993. Three runoff events, created using historical data, were undertaken in April 2005 and then again in August 2005. Both the peak flow reduction and the total volume reduction were significantly lower in April compared to August. Peak flow reduction was 13% in April versus 26% in August and the total volume reduction was 13% in April versus 25% in August. Metal retention was good for both seasons with 90% mass reduction of zinc, 82% mass reduction of lead and 72% mass reduction of copper. Plant uptake of metals was documented between 2 to 7%; however adsorption and mechanical filtration through the mulch and soil column were the most dominant metal retention processes. The metal retention was independent of the selected hydraulic loading rates (equivalent to 1.4–7.5 mm h^?1 precipitation) showing that variable inflow rates during this set of events did not affect the treatment efficiency of the system.     

Metal concentrations in marine sediments from Lebanon

Nearshore shallow marine sediment was collected from fourteen points along the Lebanese coast and analyzed for heavy metals. The samples consisting of medium to fine sand (those from Khaldé, Rmeileh, and Sidon) had generally lower metal concentrations than those made up of very coarse to coarse sand (Tabarja, Beirut, Adloun), fine to very fine sand (Beirut), and very find sand to coarse silt (Nahr Ibrahim Village). The sediments which had the highest Pb, Zn, and Mn were from Beirut and Adloun. Those with the highest Fe concentrations came from Beirut and Nahr Ibrahim Village, and the highest Cu occurred in sediments collected from Beirut and Tabarja. The metal levels found do not seem to reflect abnormal contamination in the areas sampled. More extensive work is recommended.     

调控剂对锌镉污染土壤植物修复效率及后茬蔬菜重金属吸收的影响

采用盆栽试验,在连续12年高量施用污泥有机肥引起的Zn、Cd污染土壤上种植伴矿景天,并向土壤中添加亚氨基二琥珀酸(IDS)、乙二胺二琥珀酸三钠(EDDS)、硫磺等化学调控剂及稳定剂钙镁磷肥,研究调控剂对伴矿景天吸收Zn、Cd及施用钙镁磷肥对后茬蔬菜重金属污染风险的影响,以期探索出既可提高超积累植物重金属吸取修复效率又能降低后茬农作物重金属污染风险的植物修复模式.结果表明,施用120 mmol/kg硫粉(Sed+S)处理可显著增加伴矿景天地上部生物量,分别比未加调控剂的对照处理伴矿景天(Sed)、伴矿景天添加有机调控剂(Sed+OE)处理增加34.7％和47.9％.施用3 mmol/kg IDS则显著降低了伴矿景天地上部Cd浓度,比Sed处理降低了35.5％.施用钙镁磷肥稳定剂可有效降低后茬蔬菜苋菜体内Zn、Cd浓度,降幅为57％、63％,施用4 g/kg钙镁磷肥后土壤醋酸铵提取态Zn、Cd分别较对照降低66.1％、72.4％.可见,适当施用硫肥能促进伴矿景天的生长,添加钙镁磷肥降低土壤有效态重金属浓度,减少后茬作物污染风险.     

Metal Concentrations in Organs of the Clam Amiantis umbonella and Their Use in Monitoring Metal Contamination of Coastal Sediments

The aim of this study was to evaluate the use of metal concentrations in clam organs to monitor metal contamination in coastal sediments. The concentrations of Cd, Cr, Cu, Hg, Ni, Pb, V, and Zn were measured in the kidneys, gonads, mantles, gills, digestive gland, and hearts of the infaunal clam Amiantis umbonella collected from a contaminated site near desalination and power plant discharges, and a reference site in Kuwait Bay. Metal concentrations in sediment and sediment pore water were also measured at the collection sites of individual clams at the contaminated site. The concentrations of all metals in all organs (except Zn in the digestive gland) were significantly higher in clams from the contaminated site than from the reference site. Metal concentrations in several organs in A. umbonella from the contaminated site were correlated with those in the sediments and pore waters to which they were exposed. However, fresh weights of gonads, gills, and mantles were significantly lower in clams from the contaminated site compared to the reference site, indicating that the observed elevated concentrations of metals in the organs of clams from the contaminated site largely reflect lower organ weights, rather than higher metal loads, and that these organs in A. umbonella and perhaps other clams are not appropriate for use as biomonitors of metal contamination. Metal concentrations in clam kidneys showed a wide dynamic range with respect to environmental contamination and kidney weight was not variable. Therefore, metal concentrations in clam kidneys provide a reliable biomonitor of contaminant metals in coastal marine sediments.     

Variations of Metal Availability and Bio-accessibility in Water-Logged Soils with Various Metal Contents: In Vitro Experiments

Reducing conditions of submerged soils were simulated in laboratory experiments by keeping various soil samples from urban areas under an aqueous solution in sealed flasks for several lengths of time. A polluted soil from a different origin was also included for comparison. Metals dissolved at various times were determined, and availability and bio-accessibility of metals present in the solid phase were estimated. Although significant amounts of Fe and Mn were dissolved, other metals were released to the solution to a much lesser extent. This effect is attributed to the greater solubility of reduced forms of Fe and Mn, and the small amounts of other metals dissolved during water-logging were related with metals retained by, or occluded in, the reduced Fe or Mn compounds. The amounts of available and bio-accessible metals remaining in the solid phase were significantly increased by water-logging, particularly the latter form. Such increase of metal mobility is likely to favour metal leaching to the water table as well as the transfer of potentially toxic elements to humans during recreational activities.     

我国烟用肥料中重金属含量调查分析

采集了我国12个主要植烟省份2010—2011年期间使用的95个烟用肥料样品(其中有机肥样品28个、无机复混肥样品39个、磷肥样品13个、钾肥样品15个),测定了其重金属As、Cd、Cr、Hg和Pb的含量。结果表明:我国烟用肥料中重金属含量均低于相应的国家限量标准,无超标现象,其中Pb、Cr含量相对较高,Cd、As、Hg含量相对较低;磷肥中5类重金属含量都较高,无机复混肥中As、Cd、Pb含量较高,有机肥中Hg、Cr含量较高,钾肥中Cr和Cd含量较高;黄淮烟区的肥料重金属含量较高,尤其是Cd和Cr。     

湿地生态系统对污水中重金属的修复作用

湿地污水处理技术的研究是国内外众多学者关注的热点之一。综合国内外在污水湿地处理技术方面的研究成果,对湿地生态系统及其各组成要素对重金属污染的修复作用及其作用机理进行了讨论,针对目前利用湿地生态系统进行重金属污染废水修复过程中应注意的几个问题进行了探讨,并对今后研究发展方向进行了评述。     

Addition of Calcareous Metal Waster to Acid Soils: Consequences for Metal Solubility

A model was tested which predicts the pH and solution metal concentration in the solution phase of soil amended with (waste-) incinerator fly ash (FA). Graded quantities of calcareous metal-rich FA were equilibrated with an acid clay soil, in aerated CaCl2 suspensions (0.01 M), to give a pH range of 3.1 (100% soil) to 7.5 (100% FA). As the FA loading was increased, the concentrations of Zn, Cd and Pb in solution passed through a maximum and then declined until the pH of the soil/ash mixtures approximated that of the pure FA (pHFA). This apparently complex pattern was accurately described by a simple pH- dependent adsorption equation relating adsorbed metal (Mads) to divalent metal concentration in solution (M2+) and pH through 3 constants designated n, Kads} and m: For pH < pHFA, log (Mads (M2+)n) = Kads + m pH However, at greater ash loadings the solution metal concentration and pH remained constant with FA addition and a solubility product (Ks) could be applied: For pH ≥ pHFA, og(M2+) = log Ks - 2 pH Metal concentrations in solution [Msoln] were greatest at very low FA loadings (around 2%); at lower FA additions [Msoln] was limited by total metal concentration while at higher additions of ash the solubility of metals was suppressed by the liming effect of the fly ash. It was therefore concluded that low levels of dust transfer from disposal sites to surrounding acidic soils may be the greatest source of metal pollution to biological and aquatic systems.