Effects of low pH on zooplankton in some suburban waterbodies of Chongqing City

ＥｆｆｅｃｔｓｏｆｌｏｗｐＨｏｎｚｏｏｐｌａｎｋｔｏｎｉｎｓｏｍｅｓｕｂｕｒｂａｎｗａｔｅｒｂｏｄｉｅｓｏｆＣｈｏｎｇｑｉｎｇＣｉｔｙＺｈｕａｎｇＤｅｈｕｉ（ＩｎｓｔｉｔｕｔｅｏｆＨｙｄｒｏｂｉｏｌｏｇｙ，ＣｈｉｎｅｓｅＡｃａｄｅｍｙｏｆＳｃｉｅｎｃ...     

重庆大气可吸入颗粒物中多环芳烃的分析测定

本文报告了重庆大气可吸入颗粒物(IP)中多环芳烃(PAH)的分析测定方法和结果.用GC-MS定性和定量分析了重庆IP中的PAH;研究了IP中PAH的种类和分布情况;确认重庆IP中存在甲基多环芳烃(MePAH)、约占33%;颗粒大小分布表明,约有98%PAH存在于小于3μm的颗粒中.     

Vitamins,folic acid and neural tube defects: Comments on investigations in the United States

No clear answer concerning whether multivitamin/folate supplementation prevents neural tube defects (NTDs) is provided by three studies in the United States. All these studies are occurrence in nature, no recurrence studies having been conducted. The Atlanta Birth Defects Study is subject to pronounced memory and recall biases, the length between event and interview being as long as 16 years. In a second study (Boston University), objections can be raised to certain aspects of the experimental design, and the claim that 22 per cent of women started vitamins sufficiently early after pregnancy diagnosis to influence NTD formation is suspicious. Our NICHD case control study of 541 women in California and Illinois revealed no evidence for multivitamins or folic acid preventing NTDs. U.S. public policy-makers face difficulties in applying results of recurrence or occurrence studies in high-risk areas to low-risk areas in the U.S.     

Dobbins-Camp水质模型的修正

对多宾斯 坎普 (Dobbins Camp)水质模型进行了修正 ;并分别运用传统多宾斯 坎普模型和修正模型 ,对某河段实测资料进行BOD、D(氧亏 )计算 ,比较两者之间的异同 ,及分析溶解氧对有机物降解的影响     

味精废水处理研究

味精废水具有浓度高、粘性大、pH值低、SS含量高等特点 ,其中SO42 及NH3 N含量高 ,使味精废水处理难度大。用Ca(OH) 2 中和味精废水 ,从而找出味精废水进入生化段的最佳条件     

柴油发电机噪声治理改造工程一例

介绍一例窄小空间的大功率柴油发电机噪声改造工程。通过对原机房的改造 ,增加隔声、吸声、通风等措施 ,使发电机噪声排放达标     

铜离子冲击下活性污泥微生物多样性的分子生态学分析

采用基于 16SrDNA序列分析方法 ,在长度多态 (LPM)和 16SrDNA的GC含量二维水平分析了受重金属污染的活性污泥系统内细菌的优势种类和多样性 .设计的PCR引物可以将细菌分为三大类 :即 1)proteobacterialα&δ(变形杆菌α&δ) ,2 )pro teobacterialβ&γ(变形杆菌 β&γ) ,以及 3)flexibacter(屈桡杆菌 )和革兰氏阳性菌 .分析了未受重金属驯化和受重金属驯化的两类活性污泥系统在重金属作用下优势种和多样性的变化 ,结果显示未驯化的活性污泥系统多样性减少但优势种的变化微小 ,而驯化系统优势种有较大的变化 ,但多样性基本不变 .这一结果证实驯化有助于提高微生物对重金属的抗性     

试论水质管理与饮水安全

随着生活水平的不断提高，人们对饮用水质量提出了更高的要求，而水环境质量的普通恶化又使人们不得不考虑饮用水的安全性。在简介了我国水资源现状的基础上，文中阐述了水质问题的重要性和我国水体环境质量的严峻性，指出了水质问题不仅制约着社会经济的发展，更直接地丰人们饮用水的安全性，已成为进入21世纪我国水资源问题的主要矛盾；在分析了我国水资源水质管理存在问题的基础上，从法律、法规、政策、经济等方面，着重探讨了加强水质管理与解决水资源供需矛盾和保证饮用水安全的关系。     

湿法烟气脱硫添加剂的试验研究

采用我校自主设计研制的水浴脱硫设备,以石灰石为脱硫剂,通过模拟烟气净化冷态模型试验研究了甲酸,乙酸,已二酸,草酸作为有机添加剂对湿法烟气脱硫的影响,并讨论了其机理.试验结果表明,有机酸添加剂能减缓脱硫液pH值的降低过程,能在较低的pH值时得到较高的脱硫率.实验结果为有机添加剂在湿法脱硫中的应用提供了理论依据.     

Acid resistance of methanogenic bacteria in a two-stage anaerobic process treating high concentration methanol Wastewater

In this study, the two-stage upflow anaerobic sludge blanket (UASB) system and batch experiments were employed to evaluate the performance of anaerobic digestion for the treatment of high concentration methanol wastewater. The acid resistance of granular sludge and methanogenic bacteria and their metabolizing activity were investigated. The results show that the pH of the first UASB changed from 4.9 to 5.8 and 5.5 to 6.2 for the second reactor. Apparently, these were not the advisable pH levels that common methanogenic bacteria could accept. The methanogenic bacteria of the system, viz. Methanosarcina barkeri, had some acid resistance and could still degrade methanol at pH 5.0. If the methanogenic bacteria were trained further, their acid resistance would be improved somewhat. Granular sludge of the system could protect the methanogenic bacteria within its body against the impact of the acidic environment and make them degrade methanol at pH 4.5. The performance of granular sludge was attributed to its structure, bacteria species, and the distribution of bacterium inside the granule. Translated from Acta Scientiae Circumstantiae, 2004, 24(4): 633–636 [译自: 环境科学学报]