Arbuscular mycorrhizal fungal phylogenetic groups differ in affecting host plants along heavy metal levels

Arbuscular mycorrhizal fungi（AMF） are important components of soil microbial communities,and play important role in plant growth. However, the effects of AMF phylogenetic groups（Glomeraceae and non-Glomeraceae） on host plant under various heavy metal levels are not clear. Here we conducted a meta-analysis to compare symbiotic relationship between AMF phylogenetic groups（Glomeraceae and non-Glomeraceae） and host plant functional groups（herbs vs. trees, and non-legumes vs. legumes） at three heavy metal levels. In the meta-analysis, we calculate the effect size（ln（RR）） by taking the natural logarithm of the response ratio of inoculated to non-inoculated shoot biomass from each study. We found that the effect size of Glomeraceae increased, but the effect size of non-Glomeraceae decreased under high level of heavy metal compared to low level. According to the effect size, both Glomeraceae and non-Glomeraceae promoted host plant growth, but had different effects under various heavy metal levels. Glomeraceae provided more benefit to host plants than non-Glomeraceae did under heavy metal condition, while non-Glomeraceae provided more benefit to host plants than Glomeraceae did under no heavy metal. AMF phylogenetic groups also differed in promoting plant functional groups under various heavy metal levels.Interacting with Glomeraceae, herbs and legumes grew better than trees and non-legumes did under high heavy metal level, while trees and legumes grew better than herbs and non-legumes did under medium heavy metal level. Interacting with non-Glomeraceae, herbs and legumes grew better than trees and non-legumes did under no heavy metal. We suggested that the combination of legume with Glomeraceae could be a useful way in the remediation of heavy metal polluted environment.     

Aerobic granules cultivated and operated in continuous-flow bioreactor under particle-size selective pressure

A novel method based on the selective pressure of particle size （particle-size cultivation method, PSCM） was developed for the cultivation and operation of aerobic granular sludge in a continuous-flow reactor, and compared with the conventional method based on the selective pressure of settling velocity （settling-velocity cultivation method, SVCM）. Results indicated that aerobic granules could be cultivated in continuous operation mode by this developed method within 14 days. Although in the granulation process, under particle-size selective pressure, mixed liquor suspended solids （MLSS） in the reactor fluctuated greatly and filamentous bacteria dominated the sludge system during the initial operation days, no obvious difference in profile was found between the aerobic granules cultivated by PSCM and SVCM. Moreover, aerobic granules cultivated by PSCM presented larger diameter, lower water content and higher specific rates of nitrification, denitrifieation and phosphorus removal, but lower settling velocity. Under long term operation of more than 30 days, aerobic granules in the continuous-flow reactor could remain stable and obtain good chemical oxygen demand （COD）, NH4^＋-N, total nitrogen （TN） and total phosphorus （TP） removal. The results indicate that PSCM was dependent on the cultivation and maintenance of the stability of aerobic granules in continuous-flow bioreactors.     

京津冀及周边地区低碳经济发展水平评价

随着应对全球气候变化进程的不断推进,“低碳经济”已逐渐成为世界各国实现经济社会可持续发展的必由之路.京津冀及周边地区社会经济发展较不平衡,整体推进低碳经济发展存在较大的困难,为有效促进低碳经济发展的策略选择,本文通过构建低碳经济发展水平评价指标体系,对京津冀及周边地区的低碳经济发展状况进行评价.结果显示,京津冀及周边地区低碳经济发展水平差异较大：北京低碳经济水平相对较高,其他地区距离低碳经济发展水平尚有较大差距.由此,京津冀及周边地区应根据地区经济发展特点及其低碳经济发展状况,采取不同的低碳发展策略选择,以有效推进低碳经济发展模式的顺利转型.     

宁夏南部山区新修水平梯田耕地质量提升技术研究

本文针对宁南山区新修水平梯田水土流失和土壤肥力持续衰退的问题,从梯田培肥技术、耕作技术和管理措施3个方面研究总结了宁南山区新修水平梯田耕地质量提升关键技术,为提高宁南山区新修水平梯田生产力提供了技术保障.     

影响实验室检测结果准确性的因素分析

环境监测实验室的检测结果直接为环境管理、污染治理等环保部门提供服务,因此检测数据的准确性十分重要。本文通过对影响环境监测实验室检测结果的因素人、机、料、法、环五个方面入手,详尽地研究这五个方面对检测结果的影响。     

油品装卸过程静电特性研究

为了研究油品装卸过程中的静电危险性,在两个城市的油库和加油站对油品的装油、卸油过程,以及装油的油罐车从油库向加油站行驶的过程中,油罐车内油品的油面电位进行了静电检测。通过对大量油罐车内油面电位的检测数据分析可以看出,在正常装卸油过程中,油罐车内油品的油面电位远远小于标准所规定安全油面电位,有缩短稳油时间的可能性。     

曝气膜生物反应器运行过程中污泥活性特征变化及其对膜污染的影响

研究了曝气膜生物反应器运行过程中活性污泥主要活性特征变化及其对膜污染的影响.通过排出剩余污泥的办法维持活性污泥浓度在4000 mg·L-1左右,并连续运行75 d.运行期间,每日检测活性污泥的各项性质指标便于反映污泥特性的变化.结果表明,随着反应器运行时间的延长,污泥脱氢酶活性逐渐增加,其对反应器的运行有着两方面的作用,一方面会强化微生物对污染物的去除,但另一方面则导致了胞外聚合物的增加,并加速膜污染.而污泥表观产率则随着运行时间的延长先增加后有所减少,其粒径逐渐减小,且胞外聚合物呈现增加的趋势,总的出水水质情况逐渐提高,与此同时,反应器内原生动物及后生动物在运行前期较少,而在后期大量出现.膜污染分析结果表明运行后期膜污染速度明显加快,其原因在于:污泥粒径的减小以及胞外聚合物的增加导致细小颗粒及胞外聚合物堵塞或在膜表面沉积数量增加.     

淠河灌区集中式饮用水源地水质健康风险等级研究

为了解淠河灌区集中式饮用水源地水质健康风险状况,选取Cr6+、As、Cd、Pb、Mn、Cu、Zn、Fe、F、NH+4-N等10项污染因子作为健康风险指标,运用三角模糊集理论和α-截集技术,确立置信度为0.8,得到各污染指标的健康风险区间值;同时建立模糊化特征的风险等级判别标准和判别方法.结果表明,该水源地水质总健康风险值为4,风险等级为Ⅳ级(一般).3种化学致癌物Cr6+、As、Cd合计风险区间值介于5.586×10-5~9.365×10-5之间,风险由高到低的顺序依次为:Cr6+AsCd,浓度在空间上变化不大,具有一定的负面效应,但均未超过美国环保署推荐的最大可接受水平1.0×10-4;Cr6+风险区间值较大,风险等级较高,应将Cr6+作为首要的健康风险管理控制指标.其余7种非致癌化学有毒物没有风险,不存在负面效应,非致癌健康风险明显低于致癌风险.     

应用模糊数学法综合评价营口石门水库水质级别

应用模糊数学法综合了5项主要污染指标评价了2008-2012年营口石门水库的水质级别,改变了仅凭单因子评价水质级别的方法,评价更合理,更符合实际情况。     

模拟烹饪油烟的粒径分布与扩散

烹饪油烟颗粒物粒径分布与扩散特性研究有助于解析其对室内空气质量和居民健康的影响,采用电子低压撞击器(ELPI)实时监测了油烟机开启和关闭状态下,模拟烹饪油烟发生处和3 m外位置处,0.03~10μm范围内油烟颗粒数浓度和质量浓度随粒径分布.油烟颗粒主要以655 nm以下的细颗粒为主.油烟机能够显著降低室内油烟浓度,开启油烟机后,油烟发生处颗粒数浓度从2.8×106个·cm-3降低到2.3×105个·cm-3,PM2.5(空气动力学直径≤2.5μm的颗粒)质量浓度从85.9 mg·m-3降低到6.2 mg·m-3.油烟机对PM10的净化效率高于PM2.5.油烟迅速从发生处扩散到3 m外,无通风状态下,总颗粒数浓度衰减达65%,PM2.5质量浓度衰减达75%.计算流体动力学(CFD)模拟了油烟机对油烟PM2.5质量浓度场扩散分布影响.红外摄像仪监测了油烟温度场分布扩散,以扇形向外扩散,伴随着油烟温度梯度降低.