The mutagenic potentials of tap water samples in Shanghai

The tap water samples were collected from the users' ends in several areas of Shanghai, which is located in Taihu Lake basin, Eastern China. Source water samples were also collected from two municipal source water facilities at the same time. Samples were assayed by three different short-term mutagenicity test systems: Salmonella/microsome assay (Ames test), the Arabinose resistance test (Ara test) and the SOS/umu test. The data showed that two source water samples did not display direct mutagenic potentials. Two tap water samples from city north, which were directly from Yangtze River, were also not mutagenic. Water samples from city south and middle which used source water originating from Taihu Lake were proved to be contaminated with mutagenic potentials by three different assay techniques. The boiled water displayed an even stronger mutagenic potential compared to its original tap water. The molecular mechanism of mutagenicity was associated with a reading frame-shifting potential. GC-MS analysis of tap water extracts from city middle and corresponding source water was compared. Qualitatively similar spectra were observed except for the peaks of three chlorinated aromatic hydrocarbon compounds, which existed only in the tap water. Since the water source has been polluted, raw water was heavily chlorinated in order to sterilize. More toxic compounds, including mutagens, might form during the multi-chlorination. Caution about the possibility of elevated cancer risks in the population that consumes heavily chlorinated water should be kept in mind. A cohort study in the residents of Shanghai is required.     

Ecotone shift and major droughts during the mid-late Holocene in the central Tibetan Plateau

A well-dated pollen record from a large lake located on the meadow-steppe ecotone provides a history of ecotone shift in response to monsoonal climate changes over the last 6000 years in the central Tibetan Plateau. The pollen record indicates that the ecotone shifted eastward during 6000-4900, 4400-3900, and 2800-1600 cal. yr BP when steppes occupied this region, whereas it shifted westward during the other intervals when the steppes were replaced by meadows. The quantitative reconstruction of paleoclimate derived from the pollen record shows that monsoon precipitation fluctuated around the present level over the last 6000 years in the central Tibetan Plateau. Three major drought episodes of 5600-4900, 4400-3900, and 2800-2400 cal. yr BP are detected by pollen signals and lake sediments. Comparison of our record with other climatic proxy data from the Tibetan Plateau and other monsoonal regions shows that these episodes are three major centennial-scale monsoon weakening events.     

电催化氧化中的三种催化材料处理酸性红B染料的比较研究

本文采用三种不同催化机理的材料———半导体材料TiO2 、软锰矿石和混合稀土进行了电催化氧化 (ECO)染料酸性红B的研究 ,结果表明 ,稀土材料在ECO体系中呈负催化效应 ;软锰矿石的色度去除催化效果明显 ;TiO2 的催化效果最显著 ,其色度和COD去除效果可比无催化剂时效果分别提高60 %和 75% ,可以作为电催化氧化的催化剂。并进一步研究了TiO2 用量对电催化氧化 (ECO)的影响。     

柴油机排放碳颗粒物和NOx催化净化技术的研究进展

本文从柴油机排放的特点、柴油机排放的标准、柴油机排放碳颗粒物和NOx催化净化技术等方面进行了综述与探讨,就柴油机排放碳颗粒物和NOx催化净化技术的研究提出了一些建议和设想.     

新型湿式湍流除尘器及在电厂输煤系统中的应用

介绍了针对火电厂输煤系统作业环境粉尘治理而研制开发的新型湿式湍流除尘器的设计思路、设备结构、技术特点及在电厂输煤系统的应用情况.     

粉煤灰和电石渣对聚丙烯塑料裂解的影响研究

研究了粉煤灰和电石渣对聚丙烯塑料裂解的影响,讨论了加入量对裂解速度和裂解产物的影响.结果表明:粉煤灰和电石渣都使裂解产物中的轻质部分(汽油和裂解气)增加、重油降低;粉煤灰比电石渣更能加快反应的进行,而且加入量越多,反应越快,需时越短;粉煤灰比电石渣对聚丙烯塑料的裂解具有明显的催化促进效果.     

蒽醌废水生化处理的活性污泥驯化

通过比较不同的污泥驯化方法研究了活性污泥法处理蒽醌废水的可行性.结果表明,常规的CODCr负荷提升法需要50 d才可以驯化出活性污泥.在进水中添加1 g/L葡萄糖可以快速提高污泥浓度,但是驯化出的污泥活性很低,不能满足废水的处理要求.最好的方法是添加1 g/L葡萄糖和原废水交叉循环驯化法,第28天就可以驯化出高活性的污泥.在平均进水CODCr为1 050 mg/L、HRT为24 h的条件下,CODCr去除率达到95.6%.     

程序计算法在数据处理中的应用

函数计算器程序计算功能简便易学,容易掌握,程序计算功能的深入开发,应用在一般的环境监测数据处理中,快速准确,非常便利。     

我国印染废水处理技术的现状和发展趋势

按物理法、化学法和生物法分别评述了我国印染废水治理技术的现状,并提出了今后的发展趋势。     

上流式厌氧污泥床处理城市垃圾渗沥液的试验研究

采用上流式厌氧污泥床 (UASB)处理城市垃圾渗沥液 ,结果表明 :在水力停留时间为 1～ 6d和容积负荷为 1 5～ 7 8kgCOD/m3 ·d的条件下 ,COD的去除率为 6 0 %～ 85 5 % ,且去除率随水力停留时间的延长和负荷的增加而增加 ;甲烷产量随容积负荷的增加而呈线性增加 ;沼气中甲烷的含量基本在 90 %之上 ;污泥的VSS/SS先由 0 6 2逐渐减小到 0 5 6 ,随后稳定在 0 5 4～ 0 5 8之间 ;污泥的比产甲烷速率一直维持在 0 0 0 35～ 0 0 0 5 3gCODCH4 /gVSS·gCOD·d之间 ;厌氧处理渗沥液的基本动力学常数Ks、μm、Y和kd 分别为 380 7mgCOD/L、0 0 337d-1、0 0 6 6 1gVSS/gCOD和 0 0 0 14d-1。