Heavy metal speciation in various types of fly ash from municipal solid waste incinerator

Fly ash (FA) from municipal solid waste incinerators has been known as hazardous waste, which is mostly because of the high content of heavy metal and dioxins. Besides the content, the form of the heavy metals in fly ash is also very important, because it is tightly related with the leaching behavior of fly ash in diverse circumstances. To evaluate the environment potential risk of fly ash, the Tessier chemical extraction method was adopted. In this study, four kinds of fly ash were examined, one sample from China (CFA) and the other three from Japan (RFA, CaFA and NaFA). Five metal elements were detected and they were Ni, Cr, Cd, Pb, and Cu. The result of total heavy metals’ concentration showed CFA has the lowest content. As to the Tessier chemical extraction experiments, the results show that Cd, Pb, and Cu have higher leaching risk in the environment than other heavy metals. The result of leaching test experiment showed that the more exchangeable speciation of Cd, Cr and Pb in FA, the more it could leach out in natural environment.     

介孔分子筛SBA负载CuO纳米颗粒去除H2S

采用超声波辅助浸渍法制备了一种新型SBA-15负载CuO纳米颗粒的复合介孔材料(SC),使用氮吸附、XRD、透射电子显微镜、电感耦合等离子体发射光谱、X射线光电子能谱等方法对SC进行了表征。并考察了SC对H2S的去除效果。研究结果表明:SC仍为介孔材料,超声处理会使CuO纳米颗粒更均匀地分散在主体材料孔道内;SC具有六角形长程有序性,说明辅以超声处理的浸渍方法可维持介孔材料的高度有序性;CuO纳米颗粒主要存在于载体孔道内;脱硫反应后的试样(SC-E)仍保留六角形特征,与SC相比介孔有序性降低;当Cu质量分数为3.23%时,SC的H2S穿透吸附量高达278mg/g。     

Hydrolytic Degradation of PPDO/PDLLA Blends Containing the Compatibilizer PLADO

The poly(para-dioxanone) (PPDO)/poly poly (dl-lactide) (PDLLA) blends containing various contents of compatibilizer (0, 1, 3, 5, 10 %) were prepared by solution co-precipitation, which were dissolved in 1,1,1,3,3,3-hexafluoro-2-propanol (HFIP) to form 10 % wt/vol solutions. Then in vitro hydrolytic degradation of PPDO/PDLLA blends containing poly (dl-lactide-co-para-dioxanone) (PLADO) as the compatibilizer was studied by the changes of weight loss, water absorption, thermal properties, surface morphology and mechanical properties of samples in phosphate buffered saline (pH 7.44) at 37 °C for 8 weeks. During the degradation, the weight loss and water absorption increased significantly for all blends, whereas hydrolysis rate of blends varied with the blend composition. The samples’ glass transition temperature decreased notably, while the degrees of crystallinity increased. Compared with uncompatibilized PPDO/PDLLA blends, PPDO/PDLLA blends with compatibilizer exhibited higher hydrolysis rate. The results suggested that the compatibilizer (PLADO) accelerated the hydrolysis rate of PPDO/PDLLA blends during the degradation.     

金沙江下游鱼类栖息地评估和保护优先级研究

为了给受金沙江下游水电开发影响的鱼类筛选合适的支流进行栖息地保护,对金沙江下游12条支流进行了鱼类栖息地评估和保护优先级的研究。通过河段分类-河段样方调查-河流整体评估的路线评估了支流栖息地质量;通过2次流动调查,结合历史资料获取了各支流的特有鱼类种数;最后,结合栖息地评估结果、各支流的特有鱼类种数、年径流量和水电开发强度,运用分层排序法,得出了各支流的保护优先级,由高到低依次为：牛栏江>西溪河>黑水河>普渡河>龙川江>鲹鱼河>西宁河>美姑河>以礼河>普隆河>勐果河>小江。建议将乌东德库区的龙川江和鲹鱼河、白鹤滩库区的黑水河和普渡河、溪洛渡库区的牛栏江和西溪河,以及向家坝库区的西宁河作为金沙江下游鱼类优先保护支流     

Raman and SERS spectra of thiamethoxam and the Ag3–thiamethoxam complex: an experimental and theoretical investigation

Dutch water boards have a well-established program for monitoring pesticide contamination of surface waters. These monitoring data have been processed into a graphic format accessible online and designed to provide insight into pesticide presence in Dutch surface waters and trends over time: the Pesticides Atlas (http://www.pesticidesatlas.nl). With this tool one can easily get maps of where a pesticide is being measured and where it might possibly constitute an environmental problem over the years. Presently, results of the periods 1997/1998 until 2005/2006 are available at the level of individual active ingredients. At a national level, the percentage of pesticides concentrations that exceed the maximum tolerable risk has declined 30% to 38% over the years 2003/2004 compared with 1997/1998. This means that surface water quality in the Netherlands has improved with respect to pesticides, however there are still many locations at which the measured concentrations exceed the environmental quality standards. The results on linking land use to pesticides concentrations were shown to assist in optimization of monitoring programs. By developing the present Internet tool, many new opportunities for environmental risk assessment and risk management were identified, e.g. optimization of monitoring strategies and communication to policymakers.     

Short-term impact of reservoir impoundment on the patterns of mercury distribution in a subtropical aquatic ecosystem, Wujiang River, southwest China

Surveys on pre- and post-impoundment total mercury concentrations in water, seston and fish were conducted during 2007–2008 in the Wujiang River, southwest China. Compared with the pre-impoundment, total mercury in the reservoir and downstream water rapidly increased by 164–303 % during the first half year of flooding, and then decreased by 61.7–62.2 % after 9 months of flooding. However, total mercury in seston from the reservoir and downstream generally declined. There was no significant difference in the total mercury between reservoir fish with different habitat preference and feeding habit. We find that fish tissue mercury concentration significantly increased threefold after flooding, and the increasing rate is lower than those in subarctic and temperate reservoirs. The pre- and post-impoundment fish samples exceeding the Chinese hygienic standard for tolerances of mercury in foods increased from 1.3 to 17.4 %. Long-term monitoring of fish mercury level in Wujiang River should be undertaken to ensure local food security.     

多维电极法处理高色度活性染料模拟废水影响因素分析

以活性嫩黄K 4G染料模拟废水为处理对象 ,采用多维电极法 ,考查了各种因素对多维电极系统处理活性染料时的脱色率、CODCr降解率的影响 ,结果表明 ,增多活性炭量、增大电流密度、延长电解时间和加入铁屑 ,都能使脱色率和CODCr降解率得到提高 ,电导率的变化对脱色率和CODCr降解率有一定影响。利用正交实验比较了各因素的相对影响大小     

环境信息公开及在中国的实践

环境信息公开是一种新的环境管理制度，对于提高环境决策的质量和执行，控制污染有着一定的作用。我国已在政府环境信息公开、企业环境信息公开和其它形式环境信息公开进行了一些探索和实践。在实践中，我国存在着环境信息公开法规体系不完善、公开的环境信息不准确、企业及产品的环境信息公开不充分等问题，应在健全环境信息公开的法规体系、加大企业环境信息公开力度、建设公共环境信息系统等方面做进一步的工作。     

复合构建湿地运行初期理化性质及氮的变化

研究了在间歇式进水条件下，复合构建湿地系统对氮的去除效果，阐述了湿度要、溶氧、pH等理化因子变化的原因。实验初期，系统尚处于不稳定时期，对N的去除不够理想。随着筚驼逐步步和稳定状态，对KN、NH4^ 、N、NO2^-有明显的去除效果，平均去除率分别为50％、66％和71％。硝化－反硝化作用是氨氮去除的主要途径。从总体上看，有植物系统中硝态氮的出水含量较对照系统同，说明间歇式进水以及植物的存在都有利于硝化作用的发生。实验发现，复合构建湿地在冬季仍能较好地改善水质，是一种有效的水链管理对策，对受污水体水质改善和水生态系统恢复具有重要意义。