土壤-水稻系统重金属空间异质性研究——以浙江省嵊州市为例

在嵊州农产品产地共采集94对土壤-水稻样品,研究重金属在土壤-水稻系统的污染特征及空间异质性.结果表明,土壤重金属Cd、Cu、Ni、Pb和Zn的平均含量分别为0.20、28.64、27.03、38.51和98.74mg/kg,与背景值相比较,这些重金属在研究区均有不同程度的累积,局部污染严重,但是水稻重金属没有超过国家规定的食品安全标准,仍处于安全水平.土壤重金属Cd、Cu、Ni、Pb和Zn都属于中等程度变异,其变异系数分别为45.00%、46.65%、81.54%、18.07%、32.47%.地统计学和局部Moran's I指数结果可识别出这五个重金属的污染分布情况.土壤Cd、Cu、Ni和Zn的空间分布较为相似,基本为东西部含量较低,中部较高,这与工业活动和其他的人为活动有关.土壤-水稻系统重金属的迁移、吸收主要受土壤重金属含量和土壤理化性状的影响.从长远来看,重金属污染对当地生态和居民健康仍有潜在的威胁.     

陕西省生态环境景观格局脆弱性及空间关联研究

基于地理信息系统GIS和景观格局指数分析Fragstats,研究陕西省生态环境景观格局脆弱性及空间关联,结果显示:2001年、2006年和2011年,陕西省景观格局脆弱度分别为0~7.406 6、0~7.970 5和0~8.034 8,呈下降的趋势,高脆弱区面积逐渐减小,低脆弱区和较低脆弱区面积逐渐增大.2001年、2006年和2011年的全局Moran`s I 指数分别是0.792 8、0.692 1和0.679 9,呈不断减少的趋势,景观格局脆弱度存在较强的正相关现象.局部空间自相关表明,2001年"高-高"值的区域主要分布在陕西中部和南部,2006年"高-高"值的区域分布在除中南部以外的区域,2011年"高-高"值的区域分布在除中西部以外的区域.     

Spatial and seasonal variations in bacterial communities of the Yellow Sea by T-RFLP analysis

Four typical coastal sites (rocky shore, sandy shore, mud flat shore, and artificial harbor) at the Yellow Sea were chosen to investigate the spatial and seasonal variations in bacterial communities. This was accomplished by using terminal restriction fragment length polymorphism (T-RFLP) analysis of PCR amplified 16S rDNA fragments. Two kinds of tetrameric restriction enzymes, HhaI and MspI, were used in the experiment to depict the bacterial community diversity in different marine environments. It was found that the community compositions digested by the two enzymes separately were different. However, the results of bacterial community diversity derived from them were similar. The MDA analysis results of T-RFLP profiles coming from HhaI and MspI both exhibited a significant seasonal community shift for bacteria and a relatively low spatial variation among the four locations. With HhaI as the sample, the pair wise T-tests also revealed that variations were minor between each pair of marine environments, with R ranging from 0.198 to 0.349. However, the bacterial community structure in the mud flat site depicted a larger difference than each of the other three sites (R ranging from 0.282 to 0.349).     

稀土铒掺杂TiO_2光催化剂的吸附和光催化活性研究

通过溶胶-凝胶法成功的制备了一系列Er3+掺杂的TiO2光催化剂,并通过XRD、DRS对催化剂进行了表征,结果表明所制催化剂为锐钛矿型,Er3+的掺杂有利于抑制晶粒生长,提高晶体的热稳定性。紫外-可见吸收(DRS)光谱证实,Er3+的掺杂增强了催化剂在可见光区域的吸收能力。吸附实验结果表明,Er3+的掺杂显著提高了橙黄I在TiO2催化剂表面的吸附能力,随掺杂量增加,吸附增强。活性实验结果表明,Er3+的掺杂显著提高了TiO2的光催化活性,最佳掺杂量为1.5%。     

Flow cytometric analysis of nuclear DNA stained with SYBR Green I in Phaeodactylum tricornutum北大核心CSCD

This study aimed to investigate a suitable method to stain the nuclei of Phaeodactylum tricornutum with a flow cytometer equipped with a 488-nm laser to detect the DNA. Exponentially growing cells were fixed using a 70% ethanol, a 1% glutaraldehyde and a 1% formaldehyde solution, respectively. The samples were treated with RNase A and were then stained with propidium iodide. Samples not treated with RNase A were stained with SYBR-green I. All these samples were observed under a fluorescence microscope and the content of the nuclear DNA was quantitated by flow cytometry. Specific fluoresce spots indicate that fluorescence was detected only in the nuclei of cells stained with SYBR-green I and non-RNase A treated, using fluorescence microscopy. The result of flow cytometry showed that the DNA histogram of cells stained with SYBR-green I had distinct G1 and G2/M peaks, with a fit degree (RCS) of about 3, and a coefficient of variation (CV) of around 8.6%. However, the DNA histograms of cells stained with propidium iodide had a higher CV value, a poor fit degree, and no obvious G1 and G2/M peaks. The results indicate that SYBR Green I is an adequate detection method for nuclear DNA quantitation in cells of P. tricornutum using a flow cytometer equipped with a 488-nm laser, and without RNase A treatment. © 2018 Science Press. All rights reserved.     

基于Moran’s I指数的京津冀地区PM2.5空间自相关分析

选取2014~2018年京津冀地区环境监测站点PM_2.5浓度观测数据,基于Moran's I指数,分析了该地区PM_2.5浓度的时空变化特征以及空间相关性。研究表明:2014~2018年京津冀地区PM_2.5浓度空间分布差异显著,2014年良、轻度、中度污染面积约占1/3,降至2018年以“良”为主;PM_2.5浓度空间分布北部、西部优于南部、东部地区,山区优于平原地区;PM_2.5浓度年平均值、IQR、Q1、Q3值及标准差均呈下降趋势,达到且接近于“良”以上程度的站点,从2014年2成增长至2018年8成;通过对历年及各月PM_2.5浓度全局Moran's I指数分析,I值(除7月外)均超过0.5,生成的P值均小于显著水平0.01,Z得分均超过了临界值2.58;年、月平均值均呈显著的集聚效应,年值集聚效应呈减弱趋势,月值集聚效应秋、冬季大于春、夏季,空间集聚效应与污染程度呈显著正相关;局部空间自相关历年、各月H-H集聚主要出现在京津冀南部地区,L-L集聚主要出现在北部地区。京津冀地区PM_2.5浓度值分布存在空间异质性,主要影响因素为地理、气候和经济环境。     

危险废物暂存库渗漏风险规避措施与实践

为了减少危险废物暂存库的环境风险,在项目实施中增设渗漏检测系统,通过对暂存库防渗膜进行长期的实时检测,规避了因暂存库渗漏造成的环境风险,使单层混凝土结构的暂存库实现了双层混凝土结构的遮断型填埋场才具有的渗漏检测和修补功能.渗漏检测的信息通过GSM网络进入Intemet进行数据交换,将检测信息传递到环境管理部门,提高了监督管理的水平.渗漏检测以2个检测电极间充满渗出液时电阻发生突变的特点作为HDPE膜渗漏的判据,结合渗出液的化学成分来判断渗漏的种类,利用TC35I无线模块通过GSM网进入Internet进行数据交换,实现了危险废物暂存库渗漏的网络化监测.利用HDPE膜的绝缘性提出了用偶极子检测HDPE膜漏洞的定位方法,为修补漏洞创造条件.并指出检测电压随漏洞大小、偶极子间距、贮存库液体的电阻率、供电电压的增加而增高,随偶极子距HDPE膜的距离、偶极子移动方向到漏洞的距离、暂存库液体的深度的增加而减小.     

轻型机动车尾气排放测试研究

通过在底盘测功机上进行轻型机动车的稳态负荷工况测试和瞬态负荷工况测试,进一步研究轻型机动车尾气排放污染物浓度、发动机输出功率、机动车行驶速度的相关性。并提出了通过计算排放变化率／加速度比例系数来确定稳态工况与瞬态工况的相关关系的方法,这对于I／M检测制度有很重要的技术意义。     

利用加速器质谱仪进行快速~(129)I检测的方法研究

加速器质谱法是~(129)I最灵敏的检测方法。传统方法分析样品时通常需要复杂的化学制样流程,对样品中碘元素进行分离、富集和纯化,测试周期较长,成本高。在核应急分析等类型的应用研究中,需要对大批量样品中的~(129)I含量开展快速检测,针对此类应用需求特点,本研究尝试开发一种快速、流程简便并且成本低廉的~(129)I-AMS检测方法。以三种已知~(129)I水平的国际标准物质作为研究样品,将干燥和研磨均匀化的样品粉末直接与加入过本底碘的电热导体介质(Nb粉末)混合后压入靶座,实现快速制靶,进行加速器质谱测量,再结合制靶时称量的相关质量关系数据就能直接计算得出原始样品中的~(129)I活度。通过对测量数据与已知值进行比较分析验证了方法的可靠性,估算方法的探测下限可达0.15μBq?g~(-1)。