Risk assessment on disinfection by-products of drinking water of different water sources and disinfection processes

The occurrences of trihalomethanes (THMs) and haloacetics (HAAs) in the water supply in Beijing and Canada were investigated. The concentrations of THMs and HAAs in Beijing and Canada were below the maximum contaminant levels specified by the USEPA and WHO standards. The multi-pathway risk assessment (assessed through oral ingestion, dermal absorption and inhalation exposure to drinking water) was used to assess the cancer risk and the hazard index of THMs and HAAs from fifteen waterworks in Beijing, China and three treatment plants using different disinfection processes in Canada. Residents in Beijing and residents who were served by three treatment plants using different disinfection processes in Canada had a higher risk of cancer through oral ingestion than through the other two pathways. The cancer risk resulted from disinfection by-products (DBPs) was 8.50E-05(for males), 9.25E-05(for females) in Beijing, China, while it was 1.18E-04, 1.44E-04 in Canada. The risk was higher when water treatment plants used surface water source than when they used ground water source and mixture water source in Beijing. The risk showed different changes in three treatment plants using different disinfection processes in Canada. The lifetime cancer risk for THMs followed the order: Plant 2>Plant 1>Plant 3. And, the lifetime cancer risk for HAAs was: Plant 1>Plant 2>Plant 3.     

垃圾渗滤液的膜生物反应器与传统生物工艺述评

采用文献调研法比较评价了膜生物反应器与传统生物工艺对垃圾渗滤液的处理效果。结果表明,渗滤液的水质特征(主要指COD)主要由渗滤液年龄决定,B/C值和渗滤液年龄对COD去除有重要影响。传统生物处理常采用多级组合工艺,渗滤液特性、工艺单元数、水力停留时间和有机负荷率等是影响COD去除的重要参数。近年来,MBR工艺的应用日益广泛,对于B/C值较低的老龄渗滤液,MBR工艺可获得更好的COD去除效果,也有利于废水的膜深度处理。     

偶氮染料分子结构对其生物脱色影响的研究进展

偶氮染料是工业中染料用量最大的一类,不同的分子结构对其微生物脱色性能具有一定的影响作用。文章综述了偶氮染料分子结构中的取代基种类及其取代位置对染料的脱色规律,以及分子特征结构对微生物脱色的量化分析。对目前染料生物脱色规律研究中存在的问题进行了分析,提出相应的对策措施。     

彭水电站蓄水前后鱼类群落多样性特征

根据2006-2008年9-10月渔业资源动态监测资料,分析研究了彭水电站蓄水前后坝上和坝下江段鱼类群落结构变化及其生物多样性变化特征.研究结果表明:3次监测中,调查江段出现的鱼类共有9科44属63种,其中长江上游特有鱼类22种;渔获物中,群体数量主要由体重＜50 g的小型鱼类和幼鱼组成,而群体重量主要由＜500g的中...     

水华蓝藻生物质对Cu~(2+)的吸附动力学及吸附平衡研究

文章初步研究了水华蓝藻生物质对重金属离子Cu2+的吸附特性,包括生物吸附动力学和吸附等温线。生物吸附动力学结果表明,Cu2+的生物吸附可分为两个阶段,第一个阶段能较快地达到平衡,而之后的阶段进行缓慢。透析袋处理的蓝藻生物质在不同pH(3,4,5,6)的铜离子溶液条件下,吸附效率依次为62.4%,78.1%,71.2%,60.35%,吸附最大值为7.81 mg/g。水华蓝藻生物质对Cu2+的生物吸附平衡等温线可以用Freundlich模型精确拟合。水华蓝藻生物质在处理低浓度的含Cu2+废水方面有潜力。湖泊富营养化的优势在于产生低成本的、大量的、可收集的水华,这说明自然环境中的藻类资源如蓝藻水华生物质,可能作为商业中使用的生物吸附剂。     

含油废水处理技术

概述了含油废水的来源、特点、分类及危害,介绍了含油废水的处理方法的原理、优势及存在的问题,同时简述了各种处理方法的最新研究成果,最后提出了含油废水发展趋势。     

Primary neuronal-astrocytic co-culture platform for neurotoxicity assessment of di-(2-ethylhexyl) phthalate

Plastics such as polyvinyl chlorides （PVC） are widely used in many indoor constructed environments; however, their unbound chemicals, such as di-（2-ethylhexyl） phthalates （DEHP）, can leach into the surrounding environment. This study focused on DEHP＇s effect on the central nervous system by determining the precise DEHP content in mice brain tissue after exposure to the chemical, to evaluate the specific exposure range. Primary neuronal-astrocyte co-culture systems were used as in vitro models for chemical hazard identification of DEHP. Oxidative stress was hypothesized as a probable mechanism involved, and therefore the total reactive oxygen species （ROS） concentration was determined as a biomarker of oxidative stress. In addition, NeuriteTracer, a neurite tracing plugin with ImageJ, was used to develop an assay for neurotoxicity to provide quantitative measurements of neurological parameters, such as neuronal number, neuron count and neurite length, all of which could indicate neurotoxic effects. The results showed that with 1 nmol/L DEHP exposure, there was a significant increase in ROS concentrations, indicating that the neuronal-astrocyte cultures were injured due to exposure to DEHP. In response, astrocyte proliferation （gliosis） was initiated, serving as a mechanism to maintain a homeostatic environment for neurons and protect neurons from toxic chemicals. There is a need to assess the cumulative effects of DEHP in animals to evaluate the possible uotake and effects on the human neuronal system from exoosure to DEHP in the indoor environment.     

Characterization of extracellular polymeric substances in the biofilms of typical bacteria by the sulfur K-edge XANES spectroscopy

A combined approach of physicochemical extraction and sulfur K-edge X-ray absorption near-edge structure（XANES） spectroscopy was applied to characterize the extracellular polymeric substances（EPS） of typical bacterial biofilms in this study. Physicochemical analysis showed variation of the contents of DNA,polysaccharide and protein in different fractions of EPS in different mediums. The sulfur K-edge XANES analysis yielded a variety of spectra.Spectral fitting of the XANES spectra utilizing a large set of model compounds showed that there was more reduced sulfur in both LB-EPS（loosely bound EPS） and TB-EPS（tightly bound EPS） of all the biofilms in LB medium than in R2 A medium. More oxidized sulfur was identified in LB-EPS than that in TB-EPS,suggesting different niches and physiological heterogeneity in the biofilms. Our results suggested that the sulfur K-edge XANES can be a useful tool to analyze the sulfur speciation in EPS of biofilms.     

我国辐射环境自动监测系统建设的回顾与展望

辐射环境自动监测是我国辐射环境监测工作的重要内容,是核与辐射安全监管工作的重要手段.本文回顾了“十一五”以来,我国辐射环境自动监测系统建设的进展情况和在核与辐射监管工作中所发挥的作用,总结了辐射环境自动监测系统的建设和运行经验,并对今后的工作进行了展望,提出了完善系统建设和运行的合理化建议.研究指出,作为国家辐射环境监测网的重要组成部分,辐射环境自动监测系统初步具备了对我国省会城市和主要地级城市的辐射环境质量状况的实时监测能力.但由于我国辐射环境自动监测站于2008年底才开始在全国范围内建设,起步较晚、经验不足,依然存在点位数量和代表性不够、自动化程度不够高、软件系统功能不成熟、标准化和规范化问题比较突出,缺乏质量控制技术、运行维护难度大等问题.为此本文提出：第一,增加自动监测站数量,点位布设更有针对性;第二,增加自动监测站的类型;第三,加强软件系统的分析和控制能力;第四,完善相关标准、技术规范和质保体系;第五,完善运行维护体系;第六,增强国际学习和交流.     

南京市氮氧化物排放行业分布特征及减排对策

采用污染源普查资料与实地调查相结合的方法,对南京市各行业氮氧化物(NOx)排放源及排放量进行调查和梳理。结果表明:各行业NO x排放分担率依次为电力41%、机动车25%、钢铁10%、水泥9%、石化7%、其它工业5%、居民生活3%。针对南京市现状,对重点排放源提出了NO x减排措施与对策。