沙颍河流域沉积物重金属污染特征及生态风险评价

为了解沙颍河流域沉积物重金属污染分布特征,于2013年5月采集沙颍河干流与支流共35个样点的表层沉积物,测定7种重金属(As、Cd、Cr、Cu、Hg、Pb和Zn)的含量。结果表明,沙颍河流域沉积物中As、Cd、Cr、Cu、Hg、Pb和Zn的平均含量分别为8.49、0.35、51.4、27.2、0.094、26.8和111.8 mg·kg~(-1)。Cd、Cu、Hg、Pb和Zn的平均含量均高于河南省土壤背景值,在不同程度上受到人为活动的影响。地积累指数统计结果表明,各重金属污染程度为CdHgZnPbCuCrAs,其中Cd污染最严重,91.43%的样点受到Cd污染。潜在生态危害指数结果表明,各重金属的生态风险为CdHgAsCuPbZnCr,Cd表现为很强风险,Hg表现为强风险,其他5种重金属生态风险较低。整个沙颍河流域属颍河周口段及其支流贾鲁河和清潩河的重金属污染问题最为突出,应该引起当地环保部门的重视。     

升金湖国家级自然保护区湖泊沉积物重金属分布及污染评价

为了解升金湖湿地生态系统环境状况, 采集表层沉积物样品, 分析其中重金属Cd、Cu、Pb、Zn和Hg以及粒度、TOC和TN的含量和分布特征, 运用地质累积指数法和潜在生态风险指数法进行污染程度和潜在生态风险评价。结果表明, 沉积物中Cd、Cu、Pb、Zn和Hg的平均含量分别为0.91 mg•kg-1±1.00 mg•kg-1, 37.51 mg•kg-1±7.69 mg•kg-1, 50.11 mg•kg-1±12.34 mg•kg-1, 147.98 mg•kg-1±20.97 mg•kg-1和118.7 μg•kg-1±45.6 μg•kg-1, 均高于区域水系沉积物元素背景值。相关分析显示, Cu、Pb和Zn显著正相关, 指示它们具有同源性。地质累积指数法计算结果表明升金湖重金属污染水平较低, 重金属累积程度排序为Hg>Cd>Cu>Pb>Zn;而潜在生态风险指数法结果表明升金湖整体处于中高度生态风险状态, 排序为Hg>Cd>Cu=Pb=Zn, Hg和Cd是主要的风险贡献因子。重金属污染程度与潜在生态风险指数有时候取决于环境背景值的选取。     

粤东沿海典型供水水库沉积物重金属污染特征

通过测定广东省东部沿海地区4座典型供水水库柱状沉积物主要重金属(Cr、Cu、Pb、Zn、Cd和Hg)含量,揭示了这4座水库沉积物重金属的污染特征及历史,并运用地积累指数及潜在生态危害指数法分别对表层沉积物重金属污染状态进行评价,最后分析了重金属可能来源。结果表明,除Cr外,Cu、Pb、Zn、Cd和Hg的含量均高于中国土壤环境质量标准Ⅰ类土标准值和工业化前全球沉积物重金属最高背景值,且4座水库间含量变异较大,表明4座水库沉积物均存在不同程度的重金属污染。据地积累指数评价,各重金属污染程度顺序为:Pb>Zn>Cd>Cu>Cr>Hg。潜在生态危害评价表明,河溪、汤溪及公平水库的生态危害程度要低于赤沙水库,各重金属污染程度顺序为:Cd>Hg>Pb>Cu>Zn>Cr,其中Cd和Hg对综合生态危害指数的贡献最大。4座水库沉积物重金属含量与人类活动强度表现出了较强的相互关系,流域内人类活动较强的公平、赤沙水库污染程度要明显高于人类活动较少的河溪和汤溪水库。     

临安市雷竹林土壤重金属污染特征及生态风险评价

为了解临安市雷竹林土壤重金属污染特征,采集并测定了160个土壤样品的Hg、As、Cu、Pb、Zn、Cd、Cr、Ni、Co、Mn等重金属含量,采用单因子污染指数和内梅罗综合污染指数对雷竹林土壤重金属污染程度进行分析,并应用Hankanson潜在生态风险指数法对雷竹林土壤重金属潜在生态风险进行评价.结果表明:雷竹林土壤重金属Hg、As、Cu、Pb、Zn、Cd、Cr、Ni、Co、Mn的平均含量分别为0.16、7.41、34.36、87.98、103.98、0.26、59.12、29.56、11.44、350.26mg·kg-1,Pb、Cd、Zn和Cu平均值超过浙江省土壤背景值,分别是对应背景值的2.89、1.70、1.12、1.12倍.经单因子污染指数评价,不同重金属元素的平均污染程度大小依次为Pb＞Cd＞Cu=Zn＞Hg＞As＞Ni＞Co＞Cr＞Mn,其中Pb有中度污染,Cd、Cu和Zn有轻度污染.经内梅罗综合污染指数评价,160个样点都受到不同程度的重金属污染,轻度污染、中度污染和重度污染水平所占比率分别为55.6％、29.4％和15.0％.各重金属单因子潜在生态风险指数平均值评价结果显示,只有Cd污染达到中等生态风险,其他重金属均为轻微生态风险,而局部采样点Cd和Hg单因子潜在生态风险指数最大值分别达到256.82和187.33,存在很强生态风险.重金属综合因子潜在生态风险指数评价结果表明,临安市雷竹林土壤整体上存在轻微生态风险.     

防城港临时性海洋倾倒区沉积物重金属污染现状及其生态风险评价

对防城港临时性海洋倾倒区表层沉积物重金属的含量和分布进行了对比分析,并采用污染指数法和Hakanson潜在生态风险指数法对其重金属的污染特征及潜在生态风险程度进行了评价。结果表明,倾倒区沉积物Hg、Pb、As和Zn的含量显著性升高;总体污染程度为中等污染,各重金属元素的污染程度由高到低排序依次为As(3.59)>Hg(2.19)>Pb(1.42)>Zn(1.20)>Cu(1.05)>Cd(0.91),其中As是主要污染因子;该海域表层沉积物重金属总体潜在生态风险程度为中等,各重金属元素的潜在生态风险程度由高到低排序依次为Hg(87.74)>As(35.89)>Cd(27.27)>Pb(7.08)>Cu(5.23)>Zn(1.20),其中Hg为主要潜在生态风险因子。     

白银市不同区域蔬菜地土壤重金属污染特征及生态风险评价

选取白银市城郊东大沟、西大沟蔬菜地土壤样品共128个,调查了Cu、Ni、Zn、Cr、As、Cd、Hg、Pb等8种重金属的含量,采用人为影响倍数、主成分分析法、地质累积指数法和潜在生态风险法研究评价了其污染状况。结果表明:白银市蔬菜地土壤Cu、Zn、As、Cd、Hg、Pb等6种重金属含量均超过甘肃土壤背景值,其中东大沟Zn、As、Cd和西大沟As、Cd超过了国家土壤质量二级标准。变异程度和人为影响倍数表明:东大沟Cd、Hg,西大沟Hg、As空间分布非常不均匀,受人为影响最显著。主成分分析表明:东大沟Cu、Cd、Pb和西大沟Zn、Cd含量由多种因素控制。地质累积指数(Igeo)表明:白银市蔬菜地Cd、As、Hg、Zn污染程度比较严重,达到了中度污染到强污染,尤其东大沟Cd污染部分甚至达到极强污染,Ni、Cr为无污染。潜在生态危害分析表明:单个潜在生态风险参数(Ei)和综合潜在生态风险指数(RI)均为东大沟西大沟,其中Cd、Hg和As的单个潜在生态危害程度较高。虽然东大沟蔬菜地重金属污染严重于西大沟,但研究区整体污染程度和生态危害在逐年减轻。     

北京市南沙河沉积物重金属污染特征及风险评价

北京南沙河是海淀北部地区的重要排水和风景观赏性河道,为全面了解南沙河底泥沉积物中重金属的污染特征,采集了表层沉积物样品,分析了重金属元素的含量和形态,并利用单因子指数法、Hakanson综合污染指数法和潜在生态风险指数法对沉积物重金属进行了生态风险评价.结果表明:南沙河表层沉积物各种重金属元素存在较好的同源性,污染程度为:Cr＞Cd＞Zn＞Cu＞Pb＞Ni.基于单项潜在生态风险指数的评价表明,该区域重金属生态风险等级由强至弱依次为:Cd＞Pb＞Cu≈Cr＞Ni≈Zn,其中,仅Cd具有较高的潜在生态风险,综合潜在生态风险指数表明,除了京藏高速桥河段危害等级较高外,南沙河总体处于轻微的生态风险等级.形态分析表明,Cd的酸提取态含量高,迁移性最强,最容易对生物造成直接危害,其次是Pb和Zn,Cu和Ni具有一定程度的潜在环境危害,Cr产生环境危害的可能性较小.     

大兴安岭森林土壤重金属含量空间变异与污染评价

重金属是危害森林生态健康的主要污染物之一,迄今有关大兴安岭森林土壤重金属含量、空间变异和污染程度鲜见报道。本文通过野外调查采样,应用GIS空间分析技术,结合经典重金属污染评价方法,分析了大兴安岭森林土壤Cd、Cr、Pb、Cu、Zn、Ni、Hg及As含量的空间变异与污染程度。结果表明:(1)研究区8种重金属含量具有中等空间异质性,变异系数在16.67%~35.39%。Cd、Cr、Pb、Zn、Hg、As的块金值/基台值[C0/(C0+C)]25%,其空间变异主要由母质、地形等结构性变异引起,Cu和Ni的C0/(C0+C)在25%~75%,即非结构性因素人类活动对二者的影响较大。土壤重金属含量呈斑块状、条带状和岛状分布。(2)大兴安岭森林土壤8种重金属含量主要表现为累积的特征。8种重金属含量的平均值与最大值均未超过《国家土壤环境质量标准》(GB 15618—1995)二级标准限值,其中Cu、Zn、As的最大值超过一级标准,而其他5种元素的最大值均未超过一级标准。(3)地积累指数表明,土壤Cr、Pb、Ni无污染风险,其他5种元素污染风险较低。内梅罗综合污染指数表明,土壤整体质量已经处于轻污染状态。单因子潜在生态风险指数分析表明,Cu、Ni、Pb、Cr、Zn、As不具有潜在生态风险,Hg、Cd的部分样点的单因子生态风险指数Eri值存在生态风险,其中Hg的个别特征点已经达到Ⅲ级(中等风险)水平;潜在生态风险指数表明,研究区80%的样点无潜在生态风险,20%样点处于一般生态风险水平。     

惠州市3座供水水库沉积物重金属污染特征

为了解惠州市供水水库沉积物重金属(Cr、Cu、Zn、Cd、Pb和Hg)污染状况和垂直分布特征,于2008年5月在惠州市3座具代表性的水库湖泊区采集柱状沉积物样品,运用ICPMS法检测沉积物中重金属含量,并采用地积累指数法(Igen)和潜在生态风险指数法(RI)进行污染评价,同时运用主成分分析(PCA)对沉积物中重金属的可能来源进行分析.结果表明:3座水库沉积物重金属含量随沉积深度的变化差异明显,一些重金属含量的垂直变化不明显,而另一些垂直变化明显(降低或升高),但各种重金属在不同水库沉积物中呈现特有的垂直分布特征.根据地积累指数可知,3座水库中沉积物主要以Zn和Pb污染最为严重,达到轻度至强度污染(含量分别为Zn:49.98 ～ 640.29 mg·kg-1;Pb:21.94～300.66 mg· kg-1),同时沉积物中部或底部受到轻度的Cu污染(含量为16.85 ～45.46 mg·kg-1),基本未受Cr、Cd和Hg污染.据6种重金属潜在生态风险系数[Er(i)]及潜在生态风险指数(RI)可知,3座水库沉积物的重金属潜在风险均处于较低水平.据PCA分析和相关资料可知,矿山开采与冶炼、城市化和农林业快速发展等人类活动影响了3座水库沉积物重金属的分布特征和污染.其中,Zn主要来源于矿产开采与冶炼;除矿产开采与冶炼导致沙田水库Pb污染外,机动车尾气排放和生活垃圾等是3座水库沉积物Pb污染的主要途径;Cu污染主要来源于农业和林业污染.     

黄河水系沉积物重金属赋存形态及污染特征

2004年采集了黄河干流及西纳川等支流的水系沉积物,测定了沉积物样品中Cu、Zn、Pb、Cd、Cr、As和Hg等重金属元素的含量,并用BCR连续提取法分析研究了各元素的赋存形态,同时采用地累积指数法(Igeo)和次生相原生相分布比值法(RSP)分别对黄河流域水系沉积物中重金属的污染状况及生态风险进行了评估.结果表明:黄河水系沉积物中重金属含量特征总体符合全球页岩重金属元素丰度的基本趋势,但在部分人为污染较重的区域,表现出一定的地理差异;从浓度水平衡量,重金属的污染较轻;黄河水系沉积物中Cu、Zn、Cr和As主要以残渣态(B4)形式存在,具有较好的环境稳定性,而Pb、Hg和Cd以活性较大的弱吸附态存在,可能具有相对较大的环境影响;生态风险评价的结果显示,Pb、Cd和Hg具有相对较高的生态风险指数,尤其是Pb的潜在风险应该引起重视.     

新疆石河子农耕区不同植被类型昆虫群落结构特征

2006年7～9月,用五点抽样法对新疆石河子农耕区不同植被类型中的昆虫群落结构进行调查,共采集到昆虫68种,隶属10目34科,共计6727头,其中叶蝉和蚜虫是主要害虫,瓢虫和草蛉是主要天敌昆虫。群落结构分析表明:在不同植被类型中昆虫群落多样性显著不同,以苗圃的多样性指数最高(2.5739),玉米的最低(1.0189),果木类的高于农作物的,间作的高于单纯植物的。     

干旱指标研究进展

干旱作为全球最为常见的自然灾害之一,已经对我国的农业生产造成了严重影响。为更好地预测影响作物的干旱并及时采取应对措施,综述了国内外广泛应用的各类干旱指标,包括气象指标、土壤墒情指标、作物生理生态指标及其它综合监测指标等,评述了各类干旱指标的优缺点以及在农业上的适用性,探讨了未来以作物干旱为核心的干旱指标研究拟重视的方面,以为减缓和预防干旱对农业的不良影响及制订科学的政策提供依据。     

Plan evaluation indices: A journey of evolution

AimA systemic review and analysis of evolution journey of indices, such as conformity index (CI), homogeneity index (HI) and gradient index (GI), described in the literature.BackgroundModern radiotherapy techniques like VMAT, SRS and SBRT produce highly conformal plans and provide better critical structure and normal tissue sparing. These treatment techniques can generate a number of competitive plans for the same patients with different dose distributions. Therefore, indices like CI, HI and GI serve as complementary tools in addition to visual slice by slice isodose verification while plan evaluation. Reliability and accuracy of these indices have been tested in the past and found shortcomings and benefits when compared to one another.Material and methodsPotentially relevant studies published after 1993 were identified through a pubmed and web of science search using words “conformity index”, “Homogeneity index”, “Gradient index”,” Stereotactic radiosurgery”,” stereotactic Body radiotherapy” “complexity metrics” and “plan evaluation index”. Combinations of words “plan evaluation index conformity index” were also searched as were bibliographies of downloaded papers.Results and conclusionsMathematical definitions of plan evaluation indices modified with time. CI definitions presented by various authors tested at their own and could not be generalized. Those mathematical definitions of CI which take into account OAR sparing grant more confidence in plan evaluation. Gradient index emerged as a significant plan evaluation index in addition to CI whereas homogeneity index losing its credibility. Biological index base plan evaluation is becoming popular and may replace or alter the role of dosimetrical indices.     

Fungal diversity in pigeonpea (Cajanus cajan (L.) Millspaugh) cropping system of calcareous soil

Soil mycofloral diversity plays a pivotal role in crop production and is an integral part of any ecosystem. Pigeonpea cropping system provides a congenial environment to soil microbes by fixing nitrogen and solubilizing phosphorus which in turn provides sufficient nutrients for their prolific growth. The present study was undertaken to know the fungal diversity in calcareous soil of Bihar region in India, which are not supportive to growth of many fungi owing to high calcium content. Soil samples were collected from pigeonpea cropping system treated with native and commercial isolates of phosphorus solubilizing bacteria (PSB) and plant growth promoting rhizobacteria (PGPR) along with Rhizobium. Thirty-seven species belonging to seven genera and a group of unidentified species were isolated. Aspergillus and Penicillium were the dominant genera in all the treatments. Absidia and Cunnighmella were distributed only once as rare genera. Though single species of Pythium, Rhizopus, Periconia, Geotrichum and Gliocladium genera were recorded but their occurrence was even in all the treatments. The diversity and equitability index were not varied much in different treatments except one. The deuteromucetous fungi occupied the highest space followed by zygomycetous, mycelia sterilia and mastigomycetous fungi.     

Wheat genotypic variability in grain yield and carbon isotope discrimination under Mediterranean conditions assessed by spectral reflectance

A collection of 368 advanced lines and cultivars of spring wheat(Triticum aestivum L.) from Chile, Uruguay, and CIMMYT(Centro Internacional de Mejoramiento de Maíz y Trigo), with good agronomic characteristics were evaluated under the Mediterranean conditions of central Chile. Three different water regimes were assayed: severe water stress(SWS, rain fed), mild water stress(MWS; one irrigation around booting), and full irrigation(FI; four irrigations: at tillering,flag leaf appearance, heading, and middle grain filling). Traits evaluated were grain yield(GY), agronomical yield components,days from sowing to heading, carbon isotope discrimination(D13C) in kernels, and canopy spectral reflectance. Correlation analyses were performed for 70 spectral reflectance indices(SRI) and the other traits evaluated in the three trials. GY and D13C were the traits best correlated with SRI, particularly when these indices were measured during grain filling. However,only GY could be predicted using a single regression, with ResearchNormalized Difference Moisture Index(NDMI2: 2,200; 1,100)having the best fit to the data for the three trials. For D13C, only individual regressions could be forecast under FI(r2: 0.25–0.37)and MWS(r2: 0.45–0.59) but not under SWS(r2: 0.03–0.09).NIR‐based SRI proved to be better predictors than those that combine visible and NIR wavelengths.     

Wheat genotypic variability in grain yield and carbon isotope discrimination under Mediterranean conditions assessed by spectral reflectance

A collection of 368 advanced lines and cultivars of spring wheat（Triticum aestivum L.） from Chile, Uruguay, and CIMMYT（Centro Internacional de Mejoramiento de Maíz y Trigo）, with good agronomic characteristics were evaluated under the Mediterranean conditions of central Chile. Three different water regimes were assayed： severe water stress（SWS, rain fed）, mild water stress（MWS; one irrigation around booting）, and full irrigation（FI; four irrigations： at tillering,flag leaf appearance, heading, and middle grain filling）. Traits evaluated were grain yield（GY）, agronomical yield components,days from sowing to heading, carbon isotope discrimination（△^13C） in kernels, and canopy spectral reflectance. Correlation analyses were performed for 70 spectral reflectance indices（SRI） and the other traits evaluated in the three trials. GY and △^13C were the traits best correlated with SRI, particularly when these indices were measured during grain filling. However,only GY could be predicted using a single regression, with ResearchNormalized Difference Moisture Index（NDMI2： 2,200; 1,100）having the best fit to the data for the three trials. For △^13C, only individual regressions could be forecast under FI（r^2： 0.25–0.37）and MWS（r^2： 0.45–0.59） but not under SWS（r^2： 0.03–0.09）.NIR‐based SRI proved to be better predictors than those that combine visible and NIR wavelengths.     

Ponderal indices at birth

At birth, the index weight/height is the highest correlated with weight, height and cephalic perimeter, for the index of Quételet (BMI) the correlations are also significant although lower. In both cases, the variation with age is significant. For the Rohrer index, the situation is different, the changes with age being almost absent. In front of these results, can we decide which index would be adequate to establish the nutritional status at birth? For Cole (1986), for such a ponderal index the correlation with height would have to be absent. Rolland-Cachera (1982) proposed also that the correlations with height would be absent but would be high with weight. In the case of the newborns of our study the only index being not correlated to height is the Rohrer index with low correlation also with the cephalic perimeter and high correlation with weight (although here the correlation is even higher with BMI and W/H). During the utero-placentary disfunction the foetal weight is affected but not height and cephalic perimeter: in this case, the advantage is also to an index correlated with weight but not with height.     

近50年京津冀气候舒适度的区域时空特征分析

受气候变化影响,区域气候舒适期势必会发生不同程度的变化。从气候舒适性的视角出发,利用京津冀地区1966—2015年的170个观测站点50年逐日气象资料,以温湿指数、风效指数、着衣指数及其综合指数为气候舒适性的评价指标,统计分析区域气候舒适期的起止日期、天数及其年际间变化规律,揭示京津冀区域气候舒适度的时空变化特征,为区域人口合理分布和气候资源评价提供科学依据。此外,以日为时间尺度进行气候舒适期分析,有利于气候变化背景下区域间横向和区域内纵向的比较研究。结果显示:(1)京津冀气候舒适度指数近50年来的变化趋势基本相同,综合指数呈显著增加趋势;但各地间变幅存在一定差异,其中天津气候舒适度指数变化幅度最为明显,北京变化相对平稳。(2)从气候舒适度综合指数来看,京津冀地区气候舒适期年内分布呈"M"型,舒适期相对集中在4—5月、9—10月,舒适和较舒适等级的月累计日数均达到28 d以上,其中5月气候最为舒适,舒适等级日数最多,达到24—26 d;北京年平均舒适天数最多(100 d),天津最少(91 d)。(3)从单一气候舒适度指数来看,京津冀舒适和较舒适等级的初始日期大多呈显著的提前趋势;终止日期和天数大多略有增加,但变化趋势不显著。而综合指数显示,1966—2015年较舒适等级的初始日期变化最为显著,大约每10年提前3—4 d;天津和河北终止日期变化也达到显著水平,大约每10年推迟1—2 d,北京增加趋势不明显。(4)京津冀气候舒适期的空间分布显示,舒适等级的日数从西北向东南地区呈减少特征,河北北部舒适等级的年平均日数最多达115—120 d,东南部最少,不足90 d。     

Genetic Group Index on Multiple Traits for Homogeneous Covariance Structure

A multi-trait index for ranking different genetic groups/populations with homogeneous covariance structure is developed and illustrated with live data.     

甲真菌病患者分离真菌多样性分析

为了探寻甲真菌病患者病甲部位的真菌多样性,以期对临床治疗提供参考,结合菌种培养的形态学研究和rDNA ITS序列分析的方法,对临床拟诊为甲真菌病患者的病甲分离培养菌株进行物种鉴定,并以丰富性指数(Ma)、多样性指数(H′)、均匀度指数(J)等指标分析指甲和趾甲分离真菌的多样性。2010年2月至9月在北京大学第三医院皮肤科的1 568例拟诊甲真菌病患者中,641例培养阳性,包括趾甲561例和指甲80例。检测到的皮肤癣菌占59.13%(其中红色毛癣菌为96.04%),酵母菌17.00%,其他真菌23.87%。分离自趾甲的Candida galli、Lewia infectoria和Paraconiothyrium hawaiiense,以及分离自指甲的Cyberlindnera jadinii确定为中国新记录种。趾甲分离菌的物种多样性指数H′、丰富度指数Ma和均匀度指数J均高于指甲分离菌。研究结果表明,该医院就诊甲真菌病患者可分离培养的真菌以皮肤癣菌的红色毛癣菌为主要物种,且趾甲分离菌的菌种多样性较指甲的更为明显。