纳米银与六价铬对污水生物处理的复合影响

随着纳米银的广泛使用,纳米银和重金属共同暴露的环境风险也逐渐增加.六价铬(Cr(Ⅵ))是污水处理厂主要存在的重金属之一,为了阐明纳米银和Cr(Ⅵ)的复合效应和环境影响,采用不同浓度的纳米银和Cr(Ⅵ)共同暴露于污水生物处理系统中,通过考察其对污水生物处理的复合影响,揭示二者潜在的生态风险.结果表明:(1)当纳米银≤1....     

Aerosol size distributions in urban Jinan: Seasonal characteristics and variations between weekdays and weekends in a heavily polluted atmosphere

Aerosol size distributions, trace gas, and PM(2.5) concentrations have been measured in urban Jinan, China, over 6 months in 2007 and 2008, covering spring, summer, fall, and winter time periods. Number concentrations of particles (10-2,500 nm) were 16,200, 13,900, 11,200, and 21,600 cm(?-3) in spring, summer, fall, and winter, respectively. Compared with other urban studies, Jinan has higher number concentrations of accumulation-mode particles (100-500 nm) and particles (10-2,500 nm), but lower concentrations of ultrafine particles (10-100 nm). The number, surface and volume concentrations, and size distributions of particles showed obvious seasonal variation and are also influenced by traffic emissions. Through correlation analysis, traffic emissions are proposed to be a more important contributor to Atkien-mode and accumulation-mode particles than coal firing. Around midday, the presence of nanoparticles and new particle formation is limited to pre-existing particles from traffic emissions and the mass transport of particles from suburban and rural areas. Compared with other studies in urban areas of Europe and the USA, the variation of particle number concentration and related gas concentration in Jinan between weekdays and weekends is smaller and the reasons has been deduced.     

Genetic diversity and population structure of the Chinese mitten crab <Emphasis Type="Italic">Eriocheir sinensis</Emphasis> in its native range

The Chinese mitten crab Eriocheir sinensis is an indigenous and economically important species in China, but can also be found as invasive species in Europe and America. Mitten crabs have been exploited extensively as a food resource since the 1990s. Despite its ecological and economic importance, the genetic structure of native mitten crab populations is not well understood. In this paper, we investigated the genetic structure of mitten crab populations in China by screening samples from ten locations covering six river systems at six microsatellite loci. Our results provide further evidence that mitten crabs from the River Nanliujiang in Southern China are a genetically differentiated population within the native range of Eriocheir, and should be recognized as a separate taxonomic unit. In contrast, extremely low levels of genetic differentiation and no significant geographic population structure were found among the samples located north of the River Nanliujiang. Based on the reproductive biology of mitten crabs and the geography of their habitat we argue that both natural and human-mediated gene flow are unlikely to fully account for the similar allele frequency distributions at microsatellite loci. Large population sizes of mitten crabs suggest instead that a virtual absence of genetic drift and significant homoplasy of microsatellite alleles have contributed to the observed pattern. Furthermore, a coalescent-based maximum likelihood method indicated a more than two-fold lower effective population size of the Southern population compared to the Northern Group and low but significant levels of gene flow between both areas.     

不同C/N值下亚硝酸盐氧化菌和异养菌混合体系的微生物多样性

采用PCR-RFLP技术研究了不同C/N比下亚硝酸盐氧化菌及异养菌混合体系的微牛物多样性,并探讨了微生物菌群结构与其功能(硝化件能)的关系.C/N=0时,混合体系主要由自养菌和寡营养菌(85.1%)组成,包括亚硝酸盐氧化菌(NOB)、拟杆菌门、α-变形菌纲、浮霉菌门和绿色非硫细菌中的一些菌株.C/N=0.44时,混合体系中的自养菌减少,异养菌(主要是γ-变形菌纲的成员)大量出现.C/N=8.82时,γ-变形菌纲的菌株尤其是反硝化菌Pseudomonas sp.占主导(93.8%),与此同时,随着C/N升高,该混合体系的硝化性能也由专一的亚硝酸盐氧化过程转变为同时硝化反硝化过程.微生物菌群结构的转变较好地解释了其硝化性能的改变.本研究揭示了微生物菌群结构与其功能的内在联系,同时表明PCR-RFLP技术与化学分析相结合是研究微生物菌群结构与功能的有力工具.图3表2参13     

基于指标规范变换的广义环境系统评价的普适指数公式

为了建立适用于广义环境系统评价的普适指数公式，针对传统的环境评价指数公式不具有普适、规范和通用的局限，提出适用于广义环境系统任意指标的参照值和规范变换式的设计原则和方法；该变换要求变换后的任意指标的各分级标准规范值都能被限定在各自的较小区间内，从而用规范值表示的任意指标皆"等效"于同一个规范指标；再分别用不同限定区间内生成的随机数模拟任意指标的不同分级标准的规范值，不同区间内生成的所有随机数组成不同分级标准的全部训练（学习）样本，借助免疫进化算法优化不同评价指数公式中的参数，得到适用于广义环境系统评价的9个（广义）普适指数公式，并论证了公式的可靠性.分别将9个普适指数公式用于北京市朝阳区19个监测井的9项指标的地下水水质的综合评价，以及用于郑州、西安、上海三市2000年可持续发展评价.结果表明：9个普适指数公式用于同一监测井水质的评价结果几乎完全相同，也与传统评价方法的评价结果基本一致；用于郑州、西安、上海三市可持续发展评价的结果分别是3级、3级、2级，比传统评价法更符合实际情况.9个普适指数公式使广义环境系统的评价变得简洁、规范、统一和通用；基于指标规范变换的评价指数公式的建模思想和方法对建立广义环境系统的普适智能评价模型有借鉴作用.     

焦作市某赤泥堆放场周围地下水水质评价

焦作市某赤泥堆放场一期工程采用了在堆放场底部铺设赤泥加石灰垫层和防渗膜的工程防渗处理措施.基于其防渗处理现状,文章探讨了该区域地下水对赤泥冲灰水的日最大允许入渗量,和赤泥冲灰水的实际日渗透量.评价了该防渗处理措施的可行性和在地下水日活动量稳定的状况下,该赤泥堆放场对周围地下水的影响.结果表明:将赤泥加石灰垫层用作防渗的措施值得大力推广;该堆放场在使用年限内不会对周围区域地下水水质造成太大的影响.     

Chemical behavior and risk assessment of four pesticidesin soil and water

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涕灭威对地下水污染敏感区的预测与区划试点

本文根据涕灭威在室内模拟试验与田间试验的结果，详细剖析了影响涕灭威农药在土壤中残留和移动的各种因子，建立了涕灭威农药对地下水污染的敏感性模型，并就涕灭威农药在江苏使用后对地下水可能造成污染的情况进行了预测与区划试点，结果与用美国环保局提供的ＰＲＺＭ模型计算结果和田间实测结果基本一致，本模型可用于预测涕灭威农药在其它地区使用后对地下水可能造成污染的情况。     

聚丙烯酰胺生物降解研究进展

聚丙烯酰胺（PAM）是丙烯酰胺均聚物和各种共聚物的统称，作为一种高技术含量、高附加值的重要化工产品，已广泛应用到工农业生产的各个领域并渗透到人们的日常生活中．过去通常认为聚丙烯酰胺是非常稳定的高分子聚合物，事实上，在自然条件下，聚丙烯酰胺会发生缓慢的物理降解（热、剪切）、化学降解（水解、氧化以及催化氧化）和生物降解，最终生成各种低聚物以及具有神经毒性的剧毒丙烯酰胺单体，对人体造成了极大的间接或直接危害．因此，进行聚丙烯酰胺的降解研究很有意义，而聚丙烯酰胺的生物降解研究领域几乎为空白．参33     

重庆市的可持续发展与生态环境建设

重庆市我国最大的直辖市，长江上游的经济中心，水陆交通枢纽，西部大开发战略的实施给它带来了升载难逢的发展机遇，它将成为开发西部的重要突破口和增长极，但目前严重的环境污染已成为制约重庆社会经济可持续发展的重要因素，本文首先从可持续发展的角度对重庆市生态环境的污染现状及原因进行剖析，分析了重庆市生态环境建设面临的各种机遇和挑战，最后指出了解决重庆市生态问题的主要对策措施。