人工湿地植物炭基材料特性及铁碳微电解填料制备

以人工湿地中典型植物为原料制备了不同条件下的炭基材料,并对其产率和结构特性进行了分析;同时考察了铁碳质量比、膨润土配比和焙烧温度对铁碳微电解填料除磷和化学需氧量(Chemical Oxygen Demand,COD)性能的影响,优化了植物基铁碳微电解填料的最佳配比和制备条件.结果表明:炭基材料主要由C、H、O和N四种元...     

Phylogeny of Collembola based on cuticular compounds:inherent usefulness and limitation of a character type

The phylogeny of Collembola, originally discussed from a morphological point of view, has more recently benefited from novel insights brought by molecular analyses. Both morphological and molecular characters produced a well-resolved phylogenetic hypothesis including all orders, most families, and a large number of genera. However, several conflicting points exist between molecular and morphological data, and new characters are clearly needed to resolve these inconsistencies. In this study the usefulness of a new character type not previously used in the phylogenetic study of Collembola was tested: the epicuticular chemical compounds. Our phylogenetic analysis was based on 380 compounds from 26 Collembola species. The results show good resolution for terminal branches but not for internal nodes. This is probably due to the partial involvement of epicuticular lipids in ecological functions such as water conservation and sexual attraction. Thus, this character type is appropriate for reconstructing phylogenetic relationships among recently diversified groups. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

紫贻贝消化腺淀粉酶的提取及部分性质研究

以紫贻贝为原料,从其消化腺中提取淀粉酶,确定其最佳提取条件,并探讨其部分酶学性质。采用缓冲液提取法,通过单因素试验考察提取温度、提取溶剂的pH和提取时间三个因素对紫贻贝消化腺中淀粉酶活性的影响。用平行对照试验来研究该酶的最适催化温度以及各种离子对其活性的影响。结果表明,该酶的最佳提取条件为温度20℃、pH值3.0-4.0、提取时间45min;最适反应温度为35℃,EDTA、Mg2+、Zn2+对该酶有抑制作用,而Ca2+、Mn2+对该酶有促进作用。     

用于流化床反应器的生物膜载体的比较研究

分别采用活性炭、橡胶和轻质陶粒作为生物膜载体,用流化床生物反应器进行废水处理的实验,比较3种载体材料的挂膜特性、耐磨性,并比较了对废水COD和NH3-N的去除效果。从实验中发现,活性炭具有吸附力强、比重小、挂膜时间比较短等特点,但耐磨性较差;橡胶载体具有比重较小,动力消耗较小的特点,但生物膜挂膜时间较长;陶粒比重适中,较其它两者偏大,挂膜时间最短,耐磨性能比活性炭要好,具有较强的实用价值和很大的研究潜力。     

矿业城市浅层地下水污染机制研究

分析了不同来源的污染物对矿业城市浅层地下水的污染机制，重点阐述淮南市区浅层地下水的主要污染源及其分布形状、主要污染物及其性状特征。     

垃圾焚烧发电厂周边土壤多溴联苯醚污染特征及来源解析

为了分析市政垃圾焚烧发电厂PBDEs(polybrominated diphenyl ethers,多溴联苯醚)排放对周边环境的影响,于2012年8—9月,在哈尔滨2座市政垃圾焚烧发电厂周边共采集20个表层(0~10 cm)土壤样品,分析土壤中PBDEs的污染特征及其来源. 结果表明:垃圾焚烧发电厂周边土壤中w(∑₁₂PBDEs)(12种PBDEs的质量分数之和)为5.32~169 ng/g(以干质量计,下同),平均值为62.9 ng/g;PBDEs的主要组分为BDE-209,w(BDE-209)为5.18~169 ng/g,占w(∑₁₂PBDEs)的95%以上;w(∑₁₂PBDEs)显著高于2006年哈尔滨市区污染土壤值,二者相差1~2个数量级. 由于垃圾处理年限和处理量差异较大,垃圾焚烧发电厂A周边土壤中w(PBDEs)显著高于垃圾焚烧发电厂B. 与国内其他用地类型污染土壤相比,垃圾焚烧发电厂周边土壤中PBDEs处于中度污染水平. 主成分分析结果显示,PBDEs主要来源于商用十溴联苯醚及其降解物和商用五溴联苯醚.      

土法炼锌导致土壤中铅分布特征和形态变化的研究

对贵州省赫章县土法炼锌区土壤中Pb分布特征和形态变化进行了研究。各炼锌点表层土壤中全铅含量71.8~37247.4 mg.kg-1,远高于贵州省土壤背景值(29.3 mg.kg-1)。其分布特征表现为:土壤中Pb含量总趋势随着炼锌时间增加而增加,随着距废渣堆的距离增加而降低。剖面中全铅含量分析表明Pb主要累积在土壤表层,但随着冶炼时间增加深层土壤中Pb累积程度也逐渐加大。以CaCl2和DTPA作为提取剂的简化连续提取法对土壤中Pb形态进行分析,结果显示,土壤中CaCl2和DTPA提取态Pb占全量的比例很低,平均值分别为0.3%和5%,但是其绝对含量高达6.4~1037 mg.kg-1;并随着Pb在土壤中累积时间的加长,CaCl2和DTPA提取态Pb所占比例呈显著降低的趋势,但其绝对含量逐渐增加。     

湘江微污染饮用水源水生物过滤去除特性研究

通过试验探讨了不同滤料介质组成的生物滤柱对湘江微污染水源的处理效果。结果表明,生物过滤具有良好的去浊性能,浊度的去除是传统吸附截留和生物吸附共同作用的结果;生物过滤可有效去除微污染水源中的有机物,NH+4-N,总铁和Mn2+,提高饮用水生物稳定性。颗粒活性炭-石英砂双层滤料组合要优于石英砂单层滤料和无烟煤-石英砂双层滤料,加氯水反冲洗不利于生物滤池的运行。      

贵州降雨变化趋势与极值特征分析

利用1961—2004年逐日降雨资料,分析了贵州降雨强度、无雨天数、极值降雨的变化趋势及空间分布特征。利用Mann-Kendall法与反距离权重插值法对贵州近44年降雨时空变化趋势进行了分析。利用Gumbel分布拟合最大日降雨量的概率分布特征,并利用极大似然法进行分布参数估计,推求了极端(50年,百年一遇)降雨情形。结果表明,贵州近44年来汛期有雨日降雨强度、最大日降雨量、连续3日、5日、7日无雨的出现频率呈现明显的上升趋势;最大日降雨总体由南向北减少,连续无雨天气出现频率的增加幅度空间分布总体呈东高西低的趋势。     

Residual congener pattern of dioxins in human breast milk in southern Vietnam

This study evaluated residual congener patterns of dioxin/furan (=PCDD/DF) related to tactical herbicides aerially sprayed over the regions of southern Vietnam through Operation Ranch Hand. The study focused on Cam Chinh (CC) commune, Quang Tri province (an area sprayed with tactical herbicides), and the Cam Phuc (CP) commune, Ha Tinh province (a non-sprayed area). Breast milk samples for analysis were collected in September 2002 and July 2003 from lactating primiparous and multiparous mothers born after the war (<31 years old). We found the levels of each congener in the CC commune were higher than in the CP commune, and determined specificity in the PCDD/DF congener pattern in CC commune samples by cluster analysis. The congener pattern is characterized by higher (the hexa-, the hepta-, and the octa-) chlorinated PCDD/DFs; this appears to be the same profile as that presented by pentachlorophenol (PCP), rather than 2,4,5-trichlorophenoxy acid (2,4,5-T) contaminated with 2,3,7,8-TCDD. A GC/MS study in the 1970s detected the chlorophenols 2,4-di and 2,4,6-trichlorophenol in some Agent Orange samples, which contained, like PCP, a wide variety of PCDD/DF congeners. In this context, it may be expected that certain tactical herbicides contaminated with various chlorophenol impurities, have a unique congener pattern when compared with pure 2,4,5-T formulations.