An assessment of the relative significance of risks from distal and proximal faecal hazards to the health of urban populations

卫生干预并不能可靠地改善公共健康。几乎没有做什么工作来追踪粪便污染从其源头(卫生链中的一个失误)到人口暴露点。接触可能来自当地或远离接触地点的来源。提高对城市空间粪便流动性质的理解，有助于确定最有效的城市卫生干预措施的优先次序。该项目将通过对现有知识进行文献回顾和分析来进行。然后，将对印度德里巴拉普拉盆地的各种开创性家庭进行Sanipath类型的采样和数据收集。根据这些结果，将使用各种方法追踪粪便污染的来源，例如追查用于给种植新鲜农产品的土壤施肥的粪便的来源，以及检查造成露天排水沟污染的上游群落。这将导致绘制种子家庭的粪便集水图，比较不同社区之间的差异，并最终扩大这一范围，以了解粪便污染对社区的贡献。这项研究将回答有关粪便污染在城市环境中移动的方式的重要问题，这将使更有效的干预措施能够保护社区的健康。这些途径包括不适当地处置和再利用粪便污泥和废水。如F图所示，清洁的水、卫生设施和洗手应该可以阻止粪便病原体的传播，但在现实中，即使社区采取了这些干预措施，病原体仍然可以从城市的其他地区到达，并造成高水平的污染，从而不可避免地传播疾病。探索城市环境中复杂的污染源-途径-暴露之间的联系将能够在空间上绘制粪便危害图，从而能够以证据为基础确定改善健康的最有效干预措施。

Sanitation interventions do not reliably improve public health. Little work has been done to track faecal contamination from its source (a failure in the sanitation chain) to population exposure points. Exposure may arise from sources locally or remote from the point of exposure. Improving understanding of the nature of faecal flows in the urban space could help prioritise the most effective urban sanitation interventions. The project will be carried out by conducting literature review and analysis of the current knowledge. Then Sanipath-type sampling and data gathering will be done for a variety of seminal households in the Barapullah basin in Delhi, India. From these results the sources of the faecal contamination will be traced using a variety of methods, such as following back the origins of the faeces used to fertilise the soil where the fresh produce is grown, and examining the upstream communities contributing to the contamination in the open drains. This will lead to the mapping of faecal catchments for the seminal households, comparison of how these vary between communities, and eventually the upscaling of this to understand the faecal contamination contributions to the communities. This research will answer important questions on the way that faecal contamination moves around the urban environment which will enable more effective interventions to protect the health of communities. These pathways include the inappropriate disposal and reuse of faecal sludge and waste water. As is shown in the F-diagram, clean water, sanitation and hand washing should block the transmission of faecal pathogens, but in reality, even if a community has these interventions the pathogens can still arrive from other areas of the city, and cause high levels of contamination that inevitably transmits disease. Exploration of the complex source-pathway-exposures linkages in the urban environment would enable faecal hazards to be mapped spatially, which would allow evidence-based determination of the most effective interventions to improve health.