Microbiological risk assessment and management of shallow groundwater sources in Lichinga, Mozambique
The principal Water target of the Millennium Development Goals (MDG) is to Ensure environmental sustainability by halving the proportion of people without access to safe water by 2015. Although great strides have been made in meeting this challenge in terms of provision of services since the year 2000, the safety of many these water supplies remains unknown. One of the biggest challenges therefore facing water development professionals is how to ensure sufficient levels of both quantity and guality of safe water. One of the principal mechanisms for monitoring the progress towards attaining the MDG goals for access to safe water is the UNICEF/WHO Joint Monitoring Programme (JMP). However, the JMP acknowledges that one of its current weaknesses is in assessing safety related to different technology types. In acknowledgement of these weaknesses and of the weakness of reliance on "end product testing" as a means of assuring microbiological safety, the thesis proposes improved methods of assessment and management of microbiological water safety based on a "risk" paradigm. Coinciding with proposed new risk based methods of assessing water safety outlined in the 3d edition of the World Health Organization Guidelines for Drinking Water Quality (2004), the thesis researches the risk to three well technology types in Mozambique. Principal pathways to microbiological contamination of shallow groundwater were assessed which included both the conventional aquifer pathways and preferential or localised pathways. The research adopted an experimental design that uses a mix of qualitative and quantitative data collection techniques. Data were collected over 12 months in 25 well sites in Lichinga, Mozambique. Findings from the research demonstrated that risk assessment and management are effective tools in understanding the level of safety associated with the well technologies under study. The research indicated firstly that risk assessment aids the identification of specific risk variables (of which animal faeces is a predominant risk), secondly that the use of alternative indicator organisms (e.g. enterococci) may improve risk understanding, thirdly that there is a strong statistical correlation between use of surrogates (e. g. turbidity) and microbes and fourthly that Water Safety Plans are an appropriate method of risk management. Furthermore, the research supports the JMP definitions of improved water sources, which suggest that upgraded wells are not an improved source due to their high vulnerability to contamination through localised pathways. The recommendations from the thesis include; non-inclusion of upgraded wells in the JMP in Mozambique, greater use of enterococci and turbidity as surrogate indicators of faecal pollution, the need for the development of rapid risk assessment and management techniques for rural areas in developing countries and the inclusion of localised pathways as a principal route of assessment. Potential areas of further research include field-based studies of assessment of faecal sources of Enterococci bacteria, and rapid methods for the development of model Water Safety Plans.