Nitrogen inputs to stream water from forests along an elevational gradient in New Mexico

Studies of nitrogen inputs in precipitation and outputs in stream water for a number of terrestrial ecosystems support the hypothesis that undisturbed communities have the ability to reduce losses of nitrogen via stream water. In spite of different levels of biomass, productivity and stream discharge for these communities, net losses of nitrogen were similar. Maintaining nitrogen in an organic or cation form (NH₃, NH₄⁺) is an important factor in minimizing loss. This may be accomplished by slow rates of mineralization, rapid plant uptake, and denitrification through the electron sink pathway. Denitrification by the dissimilatory pathway may also be important.     

燃气快速热水器有害物排放及其对厨房环境污染的试验研究

利用燃气快速热水器在不同使用工况下，烟气中有害气体含量及厨房环境测试数据，分析了热水器排放及其对厨房环境的污染情况。通过分析得出结论，提醒人们在使用热水器时应注意的问题。模拟工况有以下几种：厨房空气流通情况下热水器正常使用；厨房空气不流通情况下使用热水器；厨房空气流通情况下，热水器烟道部分堵塞；厨房空气不流通情况下，热水器烟道部分堵塞。     

Enhanced adsorption of Cd (II) on a hydrous Al (III) floc in the presence of a modified form of polyethylenimine

A polymer modified with succinic anhydride has been investigated for the adsorption of cadmium (II) on a freshly precipitated aluminium (III) hydroxide floc. The proportion of chelate attached to the polymer is varied to determine the relationship between carboxyl and amino groups on the polyelectrolyte, in terms of enhanced adsorption of cadmium (II) on a hydrous aluminium floc. The presence of polyelectrolyte enhanced the adsorption of 3.3 ppm Cd (II) on a 333 ppm Al (III) floc at every concentration of polyelectrolyte investigated. The proportion of succinic anhydride attached to the polymer had an impact on the increased adsorption of Cd (II) on an Al (III) floc observed. A decreasing proportion of succinic anhydride to polymer resulted in a decrease in the amount of cadmium adsorbed on the floc. Above pH 8, a decrease in the % Cd (II) adsorbed on the floc and % Al (III) retained within the floc decreases with the presence of polyelectrolyte as a result of the formation of soluble Cd-Polyethylenimine-succinic acid (PEISA) complexes. When the Al-PEISA combination was applied to a complex matrix where Cd (II), Cu (II) and Ni (II) ions competed for adsorption, enhanced adsorption was observed for Cd (II) and Ni (II). At pH 7, dissolution of the floc observed with the addition of discrete chelates was not observed with the addition of polyelectrolytes.     

谈城市水资源的可持续利用

结合我国水资源短缺及其利用现状，对水价格的状况进行了分析，提出了合理确定水价，发挥水价杠杆作用，加强政府宏观调控的具体措施，以实现城市水资源的可持续性利用。     

Detection of enteric viruses, Giardia and Cryptosporidium in two different types of drinking water treatment facilities

In this study, two types of drinking water treatment facilities (two conventional drinking water treatment plants (DWTPs) and two compact units (Cus)) were compared referring to their production capacity. Water samples were collected from three main points: (a) different water treatment steps (b) washings of sand filters and (c) distribution system at different distances from the water treatment plants. Both viruses and protozoa were concentrated from each water sample by adsorption and accumulation on the same nitrocellulose membrane filters (0.45 microm pore size). Enteroviruses were detected by plaque infectivity assay in BGM cells and HAV, HEV and Norovirus were detected by RT-PCR. Giardia and Cryptosporidium were detected by conventional staining methods and PCR. The results revealed that enterovirus load at the intake ranged between 10-15 PFU/L for the two compact units and between 4.5 and 75 PFU/L for the two conventional DWTPs. The virus load in distribution system of the first type DWTPs at 1 km from the plant was the same as that of the intake. Viruses in the other type of treatment plants CUs at 1, 5 and 7 km, were much reduced. Investigation of raw water sediments of the two DWTPs showed enterovirus counts between 12 and 17.5 PFU/L. Virus count was reduced in sand of filters after washing. Giardia cysts were equally detected by microscopy and PCR in only intake samples of EL-Hawamdia CU (33.3%) and Meet Fares DWTP (50%). Cryptosporidium oocysts were equally detected by microscopy and PCR in intake samples of Abo EL-Nomros CU (100%), EL-Hawamdia CU (66.7%) and Fowa DWTP (50%). At Meet Fares DWTP three positive intake samples for Cryptosporidium were detected by PCR, compared with only two positive samples by microscopy. Giardia cysts and Cryptosporidium oocysts were detected in raw water sediment and sand of filters before washing. Only one sample from Meet Fares DWTP sand of filters after washing was positive for both Giardia and Cryptosporidium. It can be concluded that the poor microbial quality of the water may be due to improper operational skills and management of the various water treatment plants (especially at the two high capacity treatment plants).     

室内单立管排水系统若干问题的探讨

肯定了单立管排水系统的优越性及其广泛发展前途。通过流态分析和计算，指出了影响管道内压力波动的关键问题。对系统中关键配件的结构形式提出了改进意见和设想。指出在高层建筑中推广采用塑料管材的必要性。     

沃尔斯温泉水疗中心创作启示

基于彼得·祖托的沃尔斯温泉水疗中心创作 ,对古代神庙建筑中 poche的继承和重新利用进行了阐述 ,指出历史传统是一种具有延续发展的生命力的东西 ,优秀的设计和创作都有其产生和发展的历史渊源。     

Observations on the changes in nitrate concentrations along streams in seven upland moorland catchments in Northeast Scotland

River water has been sampled under baseflow conditions in both summer and winter at c. 250-m intervals along the length of each of seven rivers in northeast Scotland, and the nitrate contents have been determined. The resultant data have been examined in the context of the nitrogen saturation hypothesis. Capacity of the catchment soils to retain nitrate was generally minimal in winter. Although biological uptake of nitrate was evident in summer, in the upper part of each catchment substantial nitrate leaching still occurred. The phenomenon was most marked in water draining from hill peats, except where these were conspicuously waterlogged. The results are discussed in the context of possible nitrogen saturation effects on upper catchment slopes.     

小导管注浆在富水大粒径砂卵石地层中的应用

结合北京地铁某站小导管注浆施工工程实例，详细阐述了小导管加工及安装工艺流程，并提出了在富水大粒径砂卵石地层中设计和施工小导管应注意的问题及处理措施。     

Lipophilic organic contaminants in the Rhine river, Germany

Detailed gas chromatographic-mass spectrometric analyses applied to eight Rhine river water samples constituted a comprehensive characterization of the low molecular weight organic contamination. Within the group of predominant anthropogenic contaminants, only a few compounds were characterized as frequently detected or priority pollutants. Numerous compounds exhibiting physiological or ecotoxicological properties are only rarely reported or still unnoticed riverine contaminants. Information on environmental behaviour or ecotoxicological effects is still limited for most of these substances. In particular, several brominated compounds (mono- and dibrominated (methoxyphenyl)propionic acids and hydroxymethylacetophenones) were identified for the first time as environmental contaminants. Quantitative analyses differentiated five groups of pollutants with respect to their concentration profiles. The spatial distribution and the intensity of emission sources on the one hand and the environmental stability as well as the tendency to adsorb on the particulate matter on the other hand determined the quantitative occurrence of individual compounds.