Biotoxicity of nickel oxide nanoparticles and bio-remediation by microalgae Chlorella vulgaris

Adverse effects of manufactured nickel oxide nanoparticles on the microalgae Chlorellavulgaris were determined by algal growth-inhibition test and morphological observation via transmission electron microscopy (TEM). Results showed that the NiO nanoparticles had severe impacts on the algae, with 72 h EC(50) values of 32.28 mg NiOL(-1). Under the stress of NiO nanoparticles, C. vulgaris cells showed plasmolysis, cytomembrane breakage and thylakoids disorder. NiO nanoparticles aggregated and deposited in algal culture media. The presence of algal cells accelerated aggregation of nanoparticles. Moreover, about 0.14% ionic Ni was released when NiO NPs were added into seawater. The attachment of aggregates to algal cell surface and the presence of released ionic Ni were likely responsible for the toxic effects. Interestingly, some NiO nanoparticles were reduced to zero valence nickel as determined by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analysis. The maximum ratios of nickel reduction was achieved at 72 h of exposure, in accordance with the time-course of changes in soluble protein content of treated C. vulgaris, implying that some proteins of algae are involved in the process. Our results indicate that the toxicity and bioavailability of NiO nanoparticles to marine algae are reduced by aggregation and reduction of NiO. Thus, marine algae have the potential for usage in nano-pollution bio-remediation in aquatic system.     

淀粉-g-丙烯酸/凹凸棒土复合物制备及其吸附废水中NH_4~＋-N性能

采用反相乳液聚合法以凹凸棒土为原料,合成了新型NH4＋-N吸附剂淀粉-g-丙烯酸/凹凸棒土,并进行了氨氮吸附对比实验。结果表明：凹凸棒土氨氮单位吸附量为4.243 mg/g;淀粉-g-丙烯酸/凹凸棒土氨氮单位吸附量为5.301 mg/g,吸附能力比未改性的凹凸棒土提高了25%。淀粉-g-丙烯酸/凹凸棒土的氨氮吸附过程比凹凸棒土更符合Freundlich等温吸附模型。随着pH、温度的升高,凹凸棒土和淀粉-g-丙烯酸/凹凸棒土对NH4＋-N吸附量逐渐增大。     

Quantification and analysis of airborne bacterial characteristics in a nursing care institution

Indoor air quality has become a critical issue because people spend most of their time in the indoor environment. The factors that influence indoor air quality are very important to environmental sanitation and air quality improvement. This study focuses on monitoring air quality, colony counts, and bacteria species of the indoor air of a nursing care institution. The regular colony counts in two different wards range from 55 to 600 cfu m(-3) Regression analysis results indicate that the bacterial colony counts have close correlation with relative humidity or carbon dioxide (CO2) but not with carbon monoxide (CO) or ozone (O3). Real-time PCR was used to quantify the bacterial pathogens of nosocomial infection, including Acinetobacter baumannii, Citrobacter freundii, Escherichia coli, Klebsiella pneumoniae, and methicillin-sensitive Staphylococcus aureus. The most abundant bacteria species in the air of the nursing care institution is E. coli.     

pH、溶解氧、叶绿素a之间相关性研究Ⅰ:养殖水体

利用国内、外近20年的资料和饮用水水源地潘家口水库现场围隔实验结果,分析养殖水体中pH、溶解氧(dissolved oxygen,DO)和叶绿素a之间的相互关系.结果表明,当叶绿素a平均含量低于10μg/L时,水体交换弱的夏季和秋季养殖水域水体中pH、DO与叶绿素a无明显相关甚至无相关;水体交换强的夏季和秋季养殖水域水...     

利用甘蔗渣制备微生物絮凝剂的预处理方法研究

通过对甘蔗渣进行不同的预处理,确定了提高纤维素酶糖化率和酱油曲霉发酵液絮凝率的方法.利用正交实验对固液比、颗粒粒径、溶剂浓度和预处理时间及其交互作用进行考察,确定较优的工艺方案.结果表明,在相同条件下,碱处理能够有效提高纤维素酶的糖化率,处理后甘蔗渣的酶解液中还原性糖浓度和酱油曲霉发酵液的絮凝率分别为3.46 g/L和...     

pH、溶解氧、叶绿素a之间相关性研究Ⅱ：非养殖水体

利用国内、外近20年的资料和饮用水水源地潘家口水库现场围隔实验结果,分析非养殖水体中pH、溶解氧（DO）和叶绿素a之间的相互关系。结果表明,当水体处于富营养化状态即叶绿素a平均含量高于10μg/L时,pH、DO与叶绿素a呈显著正相关。当叶绿素a平均含量低于10μg/L时,水体交换强或有机重污染的天然水体中DO与叶绿素a...     

低剂量臭氧的直接通加对活性污泥的活性、微生物种群及污泥减量化的影响

研究构建了2个容积为1.1 L的好氧活性污泥反应器（即1号和2号反应器）1,号反应器每天直接通加低剂量臭氧（投加量为0.01 g O3/g TSS）,不加臭氧的2号反应器作为对照平行运行,均采用每天换一次人工污水的充/排式操作。运行71 d的结果表明2,个反应器对人工污水COD的处理效果基本相同。反应器运行40 d后1,号反应器的污泥浓度比2号反应器的污泥浓度低1 400～1 700 mg/L并可稳定在8 200 mg/L,污泥减量化效果明显。低剂量臭氧的直接通加明显降低了胞内ATP浓度,并影响了微生物的抗氧化活性,2号反应器的平均超氧化物歧化酶和过氧化氢酶酶活比1号反应器分别高了24.3%和9.5%。PCR-DGGE对两反应器微生物种群的分析结果表明：Uncultured gammaproteobacteria bacteri-um、Nannocystis exedens和Uncultured actinobacterium为1号反应器的主要种群;而2号反应器的主要种群为Uncultured bacte-rium和Uncultured gammaproteobacteria bacterium。     

聚合氯化铝污泥对磷的吸附动力学及热力学

聚合氯化铝污泥（polyaluminium chloride sludge,PACS）是指以聚合氯化铝（PAC）为混凝剂的城镇给水厂在生产过程中所产生的污泥。采用批量吸附实验考察了PACS对磷的吸附动力学及热力学行为。结果表明,吸附反应发生1 h后,PACS对磷的吸附量达到平衡吸附量的75%～90%,随后PACS对磷的...     

论基于EGIS平台的放射源管理系统的开发

放射源管理系统是一种基于环境地理信息系统平台的资源管理系统,是GIS技术与环境监测技术、环境管理技术、数据库技术等各种环境信息分析和处理技术的集成。系统为环保部门提供了一个功能强大的空间信息服务和管理工具,可以直观、方便地获取放射源的监控、管理等数据信息,为环境管理部门的决策提供依据。     

Municipal solid waste source-separated collection in China: A comparative analysis

A pilot program focusing on municipal solid waste (MSW) source-separated collection was launched in eight major cities throughout China in 2000. Detailed investigations were carried out and a comprehensive system was constructed to evaluate the effects of the eight-year implementation in those cities. This paper provides an overview of different methods of collection, transportation, and treatment of MSW in the eight cities; as well as making a comparative analysis of MSW source-separated collection in China. Information about the quantity and composition of MSW shows that the characteristics of MSW are similar, which are low calorific value, high moisture content and high proportion of organisms. Differences which exist among the eight cities in municipal solid waste management (MSWM) are presented in this paper. Only Beijing and Shanghai demonstrated a relatively effective result in the implementation of MSW source-separated collection. While the six remaining cities result in poor performance. Considering the current status of MSWM, source-separated collection should be a key priority. Thus, a wider range of cities should participate in this program instead of merely the eight pilot cities. It is evident that an integrated MSWM system is urgently needed. Kitchen waste and recyclables are encouraged to be separated at the source. Stakeholders involved play an important role in MSWM, thus their responsibilities should be clearly identified. Improvement in legislation, coordination mechanisms and public education are problematic issues that need to be addressed.