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 since the year 2000, the safety of many of these water supplies remains unknown. Acknowledging the weaknesses of current water quality and hydrogeological means of assuring microbial safety, this paper has the objective of developing improved methods for the assessment and management of microbiological water safety based on a ‘risk’ paradigm. This paper provides evidence for the risk assessment of both conventional aquifer pathways and localised (short circuiting) pathways to 25 wells of three well technology types in Mozambique between 2002 and 2005.* Findings from the research outline improve methods of risk assessment and management by demonstrating that (1) the predominant source of contamination was from animal faeces rather than from latrines/septic tanks, (2) short circuiting is a significant risk to shallow groundwater in developing countries, (3) the use of alternative indicator organisms (e.g. enterococci) may improve risk understanding and (4) the World Health Organisation Water Safety Plans are recommended as an appropriate method of risk management.

Outbreaks of contamination events in many developing countries occur during periods of peak rainfall. This study presents evidence of direct pulse response of shallow groundwater contamination events to rainfall in Northern Mozambique. The objective of the paper is to establish both a statistical relationship between rainfall and contamination and to analyse the pathways through which runoff resulted in contamination. To achieve this, data from 25 wells were monitored over a 12-month period in Lichinga, Northern Mozambique, and then compared to historical rainfall from the previous 8 years. Categorical (soil survey) and parametric (water quality, rainfall, depth-to-water-table) data were further collected before, during and after the 4-month monomodal rains. Using logistic regression statistics, three distinct conclusions were drawn from the study. Firstly, the study demonstrated a direct pulse response between increased numbers of presumptive thermotolerant coliforms and enterococci bacteria. Secondly, the study observed high risk of contamination through localised, as opposed to aquifer pathways, and thirdly, the study noted a higher survival function and stability of presumptive enterococci bacteria as compared to presumptive thermotolerant coliforms in the environment and at depth.