Antioxidant and metabolism responses to polyphenol stress in cyanobacterium Microcystis aeruginosa

Three common polyphenol compounds Gallic Acid (GA), Pyrogallic Acid (PA) and Catechol (CA) are known to have allelochemical-exhibiting inhibitory effects on the growth of the cyanobacterium Microcystis aeruginosa (M. aeruginosa). Metabolism and antioxidant responses in M. aeruginosa were investigated to elucidate the mechanism by which the three polyphenols inhibit algal growth. The inhibition effects of polyphenols were in the order of CA > PA > GA. The GA and CA exposures increased protein contents, superoxide dismutase (SOD) activity, catalase (CAT) activity and soluble sugar, especially for exposure to GA of 25 mg L^?1. Soluble sugar content increased significantly especially when exposed to CA for 72 h. When exposed to PA, protein content, and SOD and CAT activities initially increased but over longer treatment time the activities decreased, in contrast to sugar content. Our results suggest that PA exposure for longer periods of time may inhibit catabolism action, while CA exposure could induce more oxide stress than GA or PA. The overall study showed that polyphenol-induced oxidative damage might be responsible for polyphenol inhibition on M. aeruginosa growth. The increases in cellular antioxidant enzymes and soluble sugar may have been to counteract the oxidative stress.     

两相厌氧消化工艺处理鸡粪

以鸡粪为发酵原料,采用序批式两相厌氧消化工艺在中温条件(37℃)下对其进行消化处理。分别将水解酸化相和产甲烷相pH值控制在5.5±0.3和7.0±0.3,通过改变进样含固率(TS)研究有机负荷(OLR)对两相消化系统处理鸡粪过程中污染物转化和去除效果的影响。结果表明,水解酸化相出水总有机碳(TOC)、挥发酸(VFAs)和氨氮(NH4+-N)浓度都随OLR升高而升高。VFAs组成相对稳定,其中乙酸占总VFAs浓度的57%～64%,其次为正丁酸和丙酸。产甲烷相出水TOC和VFAs稳定在较低水平,TOC去除率最大达到90%以上。产甲烷相进水氨氮主要以NH4+形式在反应器内不断积累。实验后期产甲烷相生物气中甲烷体积分数维持在64%上,证明两相消化系统在实验条件下良好运行。     

基于层次分析法的坦塘垃圾填埋场适宜性评价

垃圾填埋场场址的适宜性评价是生活垃圾填埋场建设和运营的前提和基础。以湖南省永州市坦塘垃圾填埋场为例,在分析研究区的地质与水文地质条件的基础上,确定了填埋场适宜性的影响因素为填埋场规模、运输条件、环境条件、建场条件和地质条件,具体包括填埋场面积及容量、综合路况条件、对地表水体污染的可能性、地形平坦程度以及场地是否处在岩溶区等条件,明确了局部地区岩溶发育是制约其适宜性的主要因素。结合垃圾填埋场的建设情况和相关规范、标准,采用层次分析法对坦塘垃圾填埋场进行适宜性评价。评价结果表明,坦塘垃圾填埋场是一个适宜场地,评价结果与实际情况相符。     

Isolation and identification of an anti-algal compound from Artemisia annua and mechanisms of inhibitory effect on algae

The goals of this work were to isolate and identify an anti-algal compound from extracts of Artemisia annua and study its mode of action on Microcystis aeruginosa. The anti-algal compound was isolated from the extracts using column chromatography and activity-guided fractionation methods. Artemisinin with strong anti-algal activity was identified by gas chromatography-mass spectrometry and ¹H Nuclear Magnetic Resonance. The EC₅₀ of artemisinin on M. aeruginosa was 3.2 mg L⁻¹. Artemisinin decreased the soluble protein content and increased the superoxide dismutase activity and ascorbic acid content of M. aeruginosa, but exerted no effect on soluble sugar content. The results suggested the mode of action of artemisinin on algae may primarily be the increasing level of reactive oxygen species in algae cells. The results of our research could aid in the development of new anti-algal substances and lead to further study of mechanisms of inhibitory effect on algae.     

二氧化硫排放测算方法与控制对策探讨

二氧化硫作为衡量企业减排成绩和环境效益的重要指标,其计算方法的选取尤为重要。通过对几种常用二氧化硫排放测算方法的研究及比较,选取了物料衡算法作为长庆油田公司第一采气厂天然气净化厂环境统计分析的基本计算依据,确定了二氧化硫排放问题的关键影响因素,同时从环境统计学角度给出了二氧化硫达标排放的控制指标及建议,为有效开展二氧化硫及其他污染物的排放问题研究,提供技术指导及方法依据。     

Scientometric analysis of coastal eutrophication research during the period of 1993 to 2008

No studies were reported on the field of coastal eutrophication research by using bibliometrics. The objective of this study was to evaluate the coastal eutrophication research performance based on all the related articles in Science Citation Index databases from 1993 to 2008. Document type, publication output, authorship, keywords, publication pattern, country, and institute of publication were analyzed. The USA contributed 35.0% of total articles where the ten major industrial countries accounted for the majority of the total production. An indicator citation per publication was presented in this study to evaluate the impact of number of authors, institutes, countries, and journals. The mean value of citation per publication of collaborative papers was higher than that of single country or institute publications. Collaboration trend was toward multi-authors, multi-institutes and multi-countries papers. This was coincident with the research trends of coastal eutrophication, which was thought to be a component of global change. Additionally, keywords analysis was used to indicate the formation and shift of hot research.     

Simultaneous determination of three herbicides by differential pulse voltammetry and chemometrics

A novel differential pulse voltammetry method (DPV) was researched and developed for the simultaneous determination of Pendimethalin, Dinoseb and sodium 5-nitroguaiacolate (5NG) with the aid of chemometrics. The voltammograms of these three compounds overlapped significantly, and to facilitate the simultaneous determination of the three analytes, chemometrics methods were applied. These included classical least squares (CLS), principal component regression (PCR), partial least squares (PLS) and radial basis function-artificial neural networks (RBF-ANN). A separately prepared verification data set was used to confirm the calibrations, which were built from the original and first derivative data matrices of the voltammograms. On the basis relative prediction errors and recoveries of the analytes, the RBF-ANN and the DPLS (D - first derivative spectra) models performed best and are particularly recommended for application. The DPLS calibration model was applied satisfactorily for the prediction of the three analytes from market vegetables and lake water samples.     

炭化污泥吸附染料的性能及其在处理印染废水中的应用

采用等温吸附实验,比较研究了活性炭和炭化污泥染料吸附特性.结果表明,活性炭和炭化污泥对次甲基蓝、酸性大红GR、碱性紫3种染料的等温(25±2℃)吸附曲线可用Langmuir或Freundlich方程来描述,回归系数为0.94～0.99,达到极显著水平(P＜O.01).根据Langmuir方程计算得出,炭化污泥对次甲基蓝...     

草甘膦母液膜分离的电渗析预处理

研究了用电渗析法去除草甘膦母液中影响膜通量的亚磷酸根,主要考察了pH值、工作电压、反应时间和温度等因素对亚磷酸根去除率的影响,并对电渗析预处理后母液纳滤膜分离的膜通量进行实验验证。实验表明：淡化液、浓缩液流量为30 L/h,pH值约为8.1,工作电压为20 V,反应时间为2 h左右,温度〈30℃时,电渗析对母液中亚磷酸...     

饮用水源水无机金属污染的应急处理

根据密云水库供水现状,针对突发性无机金属污染事件,采用聚合氯化铝辅助化学沉淀法进行应急处理。选用Cu2＋、Fe2＋、Zn2＋和Cd2＋ 4种金属离子为目标污染物,首先通过小试实验确立了最佳混凝处理条件。结果表明,调节pH值为8．0左右,可使初始浓度为5mg／L和10mg／L的Cu2＋浓度降至0．96mg／L和0．67mg／L;初始浓度为1．5mg／L和3mg／L的Fe2＋浓度降至0．27mg／L和0．24mg／L;初始浓度为0．05mg／L和0．1mg／L的Cd2＋浓度降为0．0089mg／L和0．0078mg／L;调节pH值为9．0时,可使初始浓度为5mg／L和10mg／L的Zn2＋浓度降至0．57mg／L和0．48mg／L。4种污染物出水浓度均低于国家饮用水标准。在小试基础上,在北京第九水厂开展无机金属污染处理的中试实验,结果表明所选用的聚合氯化铝辅助化学沉淀法简便易行,可实现污染物快速、有效去除。