Reflexive assessment of practical and holistic sanitation development tools using the rural and peri-urban case of Mexico

Lack of sanitation affects the lives of billions of people worldwide. It is now generally agreed that sustainable solutions to this complex problem require social and cultural factors to be addressed in addition to the habitual economic and technical aspects. Increasingly, sector professionals view the fragmented approaches to sanitation as a limiting factor. This refers to the fragmentation of the knowledge on the subject among often hermetic disciplines and to the distribution of political mandates on sanitation across many institutions, which independently tackle specific aspects of the issue. Holistic approaches have often been suggested as a solution. This paper presents the development of such a holistic approach, designed to assess sanitation development in rural and peri-urban settings. Tested in three Mexican communities, it relies on qualitative research tools to identify critical influences to sanitation development. This article presents generic results about micro and macro-factors affecting sanitation development in Mexican villages, and reflexively examines the research process as well as the strengths and limitations of the approach. The conceptual map developed for each case study successfully highlights the interconnectedness of all factors affecting sanitation development. Despite some weaknesses, these maps constitute a practical assessment tool for interdisciplinary teams deployed in integrated water and sanitation development programs and a valuable didactic tool for training activities.     

用大型底栖动物和ODP系统评价珠江的有机污染

采用大型底栖动物需氧有机体百分率ODP(oxygen demander percentage)法对广州珠江前航道、西航道和流溪河的下游段进行河流有机污染评价.结果显示:底栖动物需氧类群密度在三河段间分布确有显著性差异,并根据其ODP可以判断流溪河水质相对较好,水质级别为中国地表水环境质量标准(EQSSW)Ⅳ级,西航道和前航道水质级别都为Ⅴ级.通过测试,这一方法能成功地应用在珠江及流溪河,且该法可以较好地匹配于EQSSW五级评价系统,初步认为ODP系统可以成为一个较好的河流水质生物监测方法.图3表4参13     

Phytoremediation of Atrazine by Poplar Trees: Toxicity,Uptake, and Transformation

Toxicity, uptake, and transformation of atrazine [2-chloro-4-(ethylamino)-6-(isopropylamino)-s-triazine] by three species of poplar tree were assessed. Poplar cuttings were grown in sealed flasks with hydrophonic solutions and exposed to various concentrations of atrazine for a period of two weeks. Toxicity effects were evaluated by monitoring transpiration and measuring poplar cutting mass. Exposure to higher atrazine concentrations resulted in decrease of biomass and transpiration accompanied by leaf chlorosis and abscission. However, poplar cuttings exposed to lower concentrations of atrazine grew well and transpired at a constant rate during experiment periods. Poplar cuttings could take up, hydrolyze, and dealkylate atrazine to less toxic metabolites. Metabolism of atrazine occurred in roots, stems, and leaves and became more complete with increased residence time in tissue. These results suggest that phytoremediation is a viable approach to removing atrazine from contaminated water and should be considered for other contaminants.