On-site sanitation systems (OSS), such as pit latrines, are an important source of methane (CH4), with emissions increasing when they are wet, and this occurs when anaerobic conditions dominate. This paper presents the development of a model, which uses seasonal changes in groundwater to account for the fluctuating inundation of pit latrines, and, therefore, the associated CH4 emissions from varying degrees of anerobic conditions are examined. Given that observed timeseries of groundwater table depth at high enough spatial and temporal resolutions are often difficult to obtain in low- and middle-income countries (LMICs), inverse distance weighted (IDW) interpolation is used to generate values for a whole region, which is then used, alongside average pit latrine depth, to determine areas of pit latrine inundation. Outcomes are further informed with open-source contextual data, covering population, urban/rural split, and sanitation facility data, before using methodologies from the Intergovernmental Panel on Climate Change (IPCC) to generate CH4 emissions data. As a case study, we use data from Senegal to illustrate how this model works. Results show total CH4 emissions for the month of January to be ~1.69 kt CH4. We have also discussed the potential use of satellite remote sensing data in regions where access to historical groundwater data is limited. Understanding when the pit conditions are most likely to change could lead to incentives for better management strategies, as well as a reduction in CH4 production.

Outdoor food markets represent important locations where foodborne illnesses and other infectious diseases can spread. Countries in Africa face particular challenges given the importance of these markets in food supply and low rates of access to safely managed water and sanitation. We undertook a scoping review of evidence related to disease transmission in food markets in sub-Saharan Africa, North Africa and identified 46 papers for data extraction and synthesis. Vendor behaviour or awareness was reported in the majority of papers and about half reported on market infrastructure. Fewer studies have been reported on regulatory environments or food contamination. Studies on water supply, sanitation and handwashing facilities focused on the presence of services and did not evaluate quality, thus conclusions cannot be drawn on service adequacy. Studies of vendor behaviour were primarily based on self-reporting and subject to bias. Most studies reported high levels of vendor awareness of the need for hygiene, but where observations were also conducted, these showed lower levels of behaviours in practice. Our findings suggest that there are limited studies on environmental hygiene in outdoor food markets and this is an area warranting further research, including into the quality of services and addressing methodological weaknesses.