北京市海淀区某些重点企业周边表层土壤重金属污染风险评价与变化趋势研究

采用单因子指数法、内梅罗综合污染指数法、地累积指数法与潜在生态危害指数法对2018—2020年海淀区重点企业周边表层土壤样品中8项重金属元素全含量进行污染、累积与生态风险评价,浅析重金属累积来源及变化趋势.结果表明,PN最大值为0.55,低于0.7,土壤环境质量为安全等级.Cr、Cu、Zn、Hg、As为主要累积元素,Cu、Zn、Pb、Hg、Ni两两之间存在极显著相关性,Cr与其他元素相关性相对较弱.分析土壤中Cr累积主要受成土母质影响,Hg累积主要为点源污染造成.土壤中重金属全含量各年均值变化趋势平稳,仅个别企业周边土壤潜在生态风险相对略高,建议加强企业内部和周边土壤监测等.     

锦州市土壤重金属污染特征及生态风险评价

以锦州市为研究区,分析8种土壤重金属As、Cd、Hg、Cr、Cu、Pb、Zn、Ni的污染特征,采用单因子污染指数法、地累积指数法、内梅罗综合指数法和Hakanson潜在生态风险指数法确定锦州市土壤重金属污染程度,评价土壤重金属潜在生态风险.结果表明,锦州市土壤重金属Cd和Cr含量高于全国土壤及辽宁省土壤背景值,Cu、Hg、Ni和Pb含量高于辽宁省土壤背景值.采用单因子污染指数评价,Cd为中度污染,Hg、Pb、Cr、Ni和Cu为轻度污染.经地累积指数法评价,Cd为轻中度污染,其他重金属为无污染.内梅罗综合污染指数平均值为2.25,为中度污染等级.研究区综合潜在风险指数平均值为157.34,处于中等生态风险,造成局部地区土壤潜在生态风险较高的重金属为Cd和Hg.     

高邮湖底泥及出入湖河口表层沉积物重金属元素分布与潜在生态风险评价

为查清高邮湖底泥及出入湖河口表层沉积物重金属分布特征,评价其潜在生态风险,以湖区及周边25个底泥和沉积物样品为载体,重点研究8种重金属元素,选用单因子污染指数法、内梅罗综合指数法、地累积指数法和潜在生态风险指数法,相似比对重金属污染等级及评价潜在生态风险。测试数据表明,8种重金属元素中,仅Hg含量（平均值）未超过里下河浅洼平原表层土壤重金属元素背景值,As含量（最大值）超过农用地土壤污染风险筛选值。Pearson相关系数矩阵表明,重金属元素Ni与Cr、Pb、Zn、Cu之间具显著同源性;单因子污染指数法与内梅罗综合指数法评价结果显示,污染指数均值排序均为As＞Cd＞Pb＞Cu＞Zn＞Ni＞Cr＞Hg,但对As、Cd评价前者为轻度污染,后者为中度污染;地累积指数Igeo显示,仅As为轻度污染,其余元素均为无污染状态。沉积物单项潜在生态风险指数排序为Cd＞Hg＞As＞Pb＞Cu＞Ni＞Cr＞Zn,仅Cd属中风险,其余元素为低风险;研究区综合潜在生态风险指数RI均值为115.7,表明全区总体生态风险属于低风险状态,重金属有沿入湖河口向湖心区富集趋势。     

小秦岭金矿区西峪河底泥重金属污染的潜在生态危害评价

重金属元素易于累积,生态效应影响强烈.分析了陕豫接壤的西峪河水系沉积物中Hg、Pb、Cd、As、Cr、Cu、Zn 7种重金属元素的含量,根据地区参比值,评价了金矿活动对西峪河底泥的污染.结果显示Hg、Pb是主要的污染元素;进而用潜在生态危害指数法探讨了重金属元素污染的潜在生态危害性,认为整个西峪河流域的Hg、Pb潜在生态危害很强,Cd具有强的潜在生态危害,而Cr、As、Zn的潜在生态危害性轻微.     

豫西金矿集区矿业活动对周边农田土壤重金属影响研究

矿业活动会促进重金属向生态系统扩散,并在周边农田土壤中累积而引发潜在生态风险。豫西金矿集区矿业生产历史悠久,但在长期的矿产资源开采、选冶、加工生产过程中,缺乏对矿区周边农田土壤重金属元素的累积、空间分布和生态风险的关注,矿业活动对环境的影响程度尚不清楚。为掌握该矿集区矿业活动对周边农田土壤重金属的影响程度,支撑服务矿集区生态修复和周边农业安全生产,本文在金矿集区周边农田采集375件土壤样品,采用冷蒸气原子荧光光谱法(CV-AFS)、氢化物发生原子荧光光谱法(HG-AFS)、电感耦合等离子体发射光谱/质谱法(ICP-OES/MS)检测了样品中Cu、Pb、Zn、Ni、As、Hg、Cd、Cr重金属元素含量。用地累积指数法和潜在生态风险指数法研究了矿集区周边农田土壤中重金属元素的累积特征、空间分布和生态风险,分析评价了矿集区矿业活动对周边农田土壤重金属的影响。研究结果表明：(1)矿集区周边农田土壤中Cu、Pb、Zn、Ni、As、Hg、Cd、Cr含量平均值都低于国家农田土壤重金属污染风险筛选值,但均高于背景值,分别是背景值的1.47、3.24、2.06、1.05、1.03、1.52、2.77、1...     

农田表层土壤中重金属潜在生态风险效应研究

皖江经济区南陵县是我国商品粮生产基地之一,该区农田表层土壤中重金属元素潜在生态风险效应研究对于提高粮食安全具有重要意义。文章以南陵县基本农田区作为主要研究区,按土地质量地球化学调查评价要求,布设和采集了0~20 cm深度的表层土壤样品500组,分别监测了土壤中Cd、Pb、Cr、Hg、As、Cu、Fe、Mn和Zn等重金属含量现状,并采用地质累积指数法和潜在生态风险指数法量化解析了这些重金属在土壤中的潜在生态风险效应。结果表明:（1）土壤中除了Cr元素,其余重金属元素都不同程度存在异常;（2）局部土壤中Cd、Hg和Fe等元素含量存在异常,平均含量分别是所在区域背景值的1.92,1.95,7.13倍,存在潜在生态风险的影响;（3）土壤中重金属元素的潜在生态风险值（平均RI值）为164.5,Cd和Hg元素为主要影响元素。     

陕西潼关县金矿矿区周边农田土壤重金属生态健康风险评价

为了解潼关金矿矿区早期粗放式的矿业活动对矿区周边农田土壤的重金属污染状况的影响以及对暴露人群的不良健康效应的评价,采用地质调查工程选取了矿区附近6块农田土壤为研究对象,通过X射线荧光光谱分析法测定了68个土壤样本中Cd、Hg、As、Pb、Cr、Cu、Ni、Zn等8种土壤重金属含量,采用地累积指数法、潜在生态危害指数法和健康风险评估模型分别评价该区土壤重金属污染程度、潜在生态风险和人体健康风险。结果表明,该区农田土壤中Cd、Hg、Pb、Cu、Ni、Zn 6种重金属平均值高于潼关县土壤背景值,呈现不同程度的积累;Pb、Hg、Cd的土壤积累含量不仅超出了土壤重金属污染对农产品质量存在安全风险的最低限值农用地土壤污染风险筛选值,还分别以41.2%、72.1%、14.7%的超标率超出了土壤重金属污染对农产品质量存在安全风险的最高限值农用地土壤污染风险管制值;研究区土壤重金属污染评价显示,土壤中Hg、Cd、Pb总体污染程度最重,Cu、Zn总体呈现轻—重污染,Ni、Cr、As总体呈现无污染状态。生态风险评价显示,Hg、Cd、Pb为主要生态危害元素,Hg为极强风险,Cd和Pb为强风险。人体健康风险表明,研究区重金属对儿童的非致癌风险显著,Pb、Hg为主要非致癌因子;致癌风险均在合理范围,Cd致癌风险最大,手-口摄入为最主要的暴露途经,儿童更易受到重金属污染威胁。     

黔西北典型铅锌矿区土壤重金属污染特征及其来源分析

研究矿区周边土壤重金属污染状况及其来源对土壤污染治理具有重要意义。本文以黔西北玉兰、永昌和杉树林铅锌矿周边农田土壤为研究对象,测定了土壤中的Pb、Zn、Ni、Cd、Cr、As、Hg和Cu含量,采用单因子污染指数、内梅罗综合污染指数和潜在生态风险指数评价了重金属污染状况,并结合多元统计分析探讨重金属的来源。结果表明,玉兰和永昌矿区Pb、Zn、Cd和Cu为重度污染,杉树林矿区Pb、Zn、Cd、Hg和As为重度污染,其余重金属为轻度或无污染,综合污染指数显示3个矿区均属重度污染。潜在生态风险指数表明玉兰和永昌矿区Cd、Hg和Pb及杉树林矿区Cd、Hg、Pb和As为中度或以上生态风险,其余重金属为低生态风险,综合生态风险指数显示玉兰和杉树林为极高生态风险,永昌为高生态风险。主成分分析表明,Pb、Zn、Hg、As和Cd主要源于矿山开采等人为活动,Ni和Cr主要源于成土母质,Cu污染是采矿作业和农业活动共同作用的结果。     

小秦岭金矿区西峪河底泥重金属元素污染的潜在生态危害评价

重金属元素易于累积,生态效应影响强烈。分析了陕豫接壤的西峪河水系沉积物中Hg、Pb、Cd、As、Cr、Cu、Zn 7种重金属元素的含量,根据地区参比值,评价了金矿活动对西峪河底泥的污染。结果显示Hg、Pb是主要的污染元素;进而用潜在生态危害指数法探讨了重金属元素污染的潜在生态危害性,认为整个西峪河流域的Hg、Pb潜在生态危害很强,Cd具有强的潜在生态危害,而Cr、As、Zn的潜在生态危害性轻微。     

西安市公园土壤重金属元素含量水平及风险评价

利用X-Ray荧光光谱仪对西安市城市公园表层土壤的Pb、Cu、Zn、Cr、Mn、As的质量分数进行了分析,阐明了这几种重金属元素的分布特征,并用内梅罗综合污染指数法和潜在生态风险指数法对其进行了评价.结果表明,As在个别公园呈现富积;Zn和Mn普遍存在一定程度的富积;Cu、Pb在公园内的累积程度相对较大.西安市公园土壤重金属元素属于中等污染,其潜在生态风险处于中等水平,各重金属元素的潜在生态风险系数大小顺序为Pb=As>Cu>Cr>Mn>Zn.     

CSAMT 法在辽西康杖子区深部探矿中的应用

可控源音频大地电磁法(CSAMT)具有探测深度大、横向分辨率高、抗干扰能力强的特点,在深部找矿勘探中有着重要的指导意义。肖家营子铜钼矿床是辽西地区一个大型矽卡岩型金属矿床,大部分矿体是隐伏矿体,矿区外围的康杖子区与本区有相似的成矿地质环境,成矿地质条件优越.矿体与围岩电性差异明显,通过应用CSAMT,矿体具有低电阻特点,根据成果推断解释,对深部有利成矿部位进行了钻探验证,取得了理想的探矿效果,在矿区外围取得第二深度空间找矿重大突破。     

Geography in general education in Nigeria

This paper traces the development of geographic education in Nigeria and examines the views of geographers, other academics, students and the public at large about the importance of geography. Geography's value is immense despite the non-professional nature of the discipline. Nevertheless, there is a need to define geography's status and ensure career prospects for students. The Nigerian Geographical Association (from classroom teaachers to top geographers) must promote geography, improve its status in schools and universities, and continuously restructure its content and methods to address pertinent social needs.     

Trends in landslide occurrence in Nepal

Nepal is a mountainous, less developed kingdom that straddles the boundary between the Indian and Himalayan tectonic plates. In Nepal, landslides represent a major constraint on development, causing high levels of economic loss and substantial numbers of fatalities each year. There is a general consensus that the impacts of landslides in countries such as Nepal are increasing with time, but until now there has been little or no quantitative data to support this view, or to explain the causes of the increases. In this paper, a database of landslide fatalities in Nepal has been compiled and analysed for the period 1978–2005. The database suggests that there is a high level of variability in the occurrence of landslides from year to year, but that the overall trend is upward. Analyses of the trends in the data suggest that there is a cyclicity in the occurrence of landslide fatalities that strongly mirrors the cyclicity observed in the SW (summer) monsoon in South Asia. Perhaps surprisingly the relationship is inverse, but this is explained through an inverse relationship between monsoon strength and the amount of precipitation in the Hill District areas of Nepal. It is also clear that in recent years the number of fatalities has increased dramatically over and above the effects of the monsoon cycle. Three explanations are explored for this: land-use change, the effects of the ongoing civil war in Nepal, and road building. It is concluded that a major component of the generally upward trend in landslide impact probably results from the rural road-building programme, and its attendant changes to physical and natural systems.     

2010年的美国铀矿业

2010年,美国铀矿总共施工7 209个钻孔,总进尺1 493 520 m;生产铀1 628.55 t;铀矿业总支出费用为2.773亿美元,其中铀矿地勘费支出为3 450万美元,占铀矿业总费用的12.44%。铀矿地勘钻探费用为4 460万美元,占铀矿业总费用的16.08%。     

地下水环境中的硫代砷研究进展

硫代砷是富硫化物地下水中砷的重要形态,对环境和人类健康有潜在威胁。目前硫代砷研究程度尚低,本次主要针对国内外地下水（地热水）中硫代砷的存在形态,水文—生物—环境地球化学过程,样品保存,定量检测方法等方面进行研究。结论如下:pH, 氧化还原电位,硫化物含量和微生物作用等是影响地下水中硫代砷稳定存在和形态分布的重要因素。含铁矿物能与水中的硫代砷形成配位键对其进行吸附,吸附性普遍弱于（亚）砷酸盐,因此,地下水中硫代砷可能表现出更强的迁移性。用于硫代砷检测的自然水样在采集中可采取过滤,速冻,厌氧和低温短期保存的操作流程,以减缓该形态的转化甚至消失。色谱联用ICP-MS系统可用于自然水样中硫代砷的分离定量检测,紫外—可见分光光度法和X射线吸收光谱法在不同场景下也可对硫代砷进行定量和表征分析。地热水和浅层地下水中均可能存在硫代砷,由于水样中硫代砷的不稳定性,室内检测和分析难以准确反映现场过程,因此,野外样品保存技术和现场检测方法的更新可能在未来有更大研究空间,值得进一步探索。     

花岗岩地区地下水水文地质特征分析

通过对泰安市岱岳区花岗岩地区地下水的形成条件、地下水类型、分布状况、水文地质特征以及地下水补给、径流、排泄条件的分析,指出了花岗岩地区供水方向。     

Recent advances in aquaculture in Japan

Conclusions During the last ten years, aquaculture, especially mariculture has undergone remarkable expansion to counter-balance the gap between the supply and demand of fishery products in Japan. Its expansion has also been supported by the traditional preference of the Japanese people for seafood. Mariculture is now being forced to change its structure due to adverse economic circumstances such as the rise in the cost of energy, feeds and other materials for culture, low market prices, deterioration of environmental conditions, and many other factors. Before these constraints can be resolved, advanced scientific knowledge and technologies must be integrated to develop new types of aquaculture. Expansion of maricultural activities to more open-sea and off shore areas would be one route to follow. Technologies for the development of formulated diets not only for young but also for adults and larvae, establishment of feeding standards, prevention of epizootic diseases must support the establishment of modern aquaculture.The culture-based fisheries, or marine ranching, is becoming a subject for further development in Japan. Much research work has been conducted with a great degree of governmental support. Establishment of a net work of seedstock production farms has made it possible to carry out releasing experiments on a large scale. A newly integrated restoration system could be developed on the basis of these experiments, even though the profits resulting from the artificial restoration of stocks is not thouroughly verified at present. The commencement of a national scheme for culture-based fisheries would be a manifestation of the enthusiasm of the Japanese fish industry.     

Some Measurements of Radon in Soils and in Stream-Water in County Durham

Radon is a radioactive gas emanating naturally from uranium rich granites and shales. It may be emitted from the ground surface into the atmosphere as a gas, or it may be dissolved into stream water and transported over distance. The levels of radon gas in soils at ground surface depend on a number of factors relating to the source of the gas and to its transmission. Igneous rocks contain the highest mean concentrations of radium and uranium. The depth of cover is relevant also. Surveys over the years by the National Radiological Protection Board (NRPB) and others have indicated that the highest concentrations in the United Kingdom occur in Cornwall, Devon and northeast Scotland. However, recent reports have indicated that high concentrations of the gas may be detected in small pockets in counties outside of those considered at high risk. This survey relates to a series of measurements taken in and around Darlington, County Durham. The results showed the presence of small areas with strong concentrations of radon in soil gas, but only minor levels of dissolved gas in stream waters.     

内蒙古苏尼特地下水氟污染形成机理研究

为了研究内蒙古苏尼特地区地下水氟污染机理,本文运用水文地球化学分类方法,从水文地质、水化学特征两方面研究其地下水的水质特征、氟的起源、分布规律及污染形成机理。研究结果发现:高氟地下水的主要水质类型为HCO3—Na型,pH值在7.08～9.38之间,氟浓度与井深有关,即井越浅,氟浓度越高;地下水中氟浓度最高达14.78mg/L,5～9月地下水氟浓度相对增长率在7.8～23.1之间;F-浓度与Li+、Br-相关系数达0.89和0.82,受断层影响的深层地下水中F-浓度几乎与Li+、Br-没有相关关系,这暗示着氟来源于浅部,并受到强烈的蒸发作用影响而使水中的氟浓缩;地质调查发现该地区还有数个萤石矿存在,显微镜分析结果证实表层土壤中普遍存在CaF2,地下水中的氟来自CaF2。高氟地下水存在于潜水层,深部含水层的地下水可供开采。从断层带涌出的水对潜水层有稀释作用。