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

点击翻译按钮获取中文摘要

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.