Characterising pathogen contamination in urban groundwater in Kabwe, Zambia: a comparative study using multiple pollution indicators and contributing risk factors

Low income urban communities across Africa depend on the use of shallow, often polluted, groundwater sources for drinking and domestic use. The factors influencing microbiological contamination in groundwater are complex and require multiple assessment approaches. Microbial contamination is often predicted using sanitary risk assessments and characterised using thermotolerant coliforms and faecal streptococci as indicators. This paper evaluates this approach against molecular pathogen broad screening, in-situ optical fluorescence for tryptophan (a protein marker associated with waste water) and inorganic chemistry, in groundwater across Kabwe, Zambia. Thermotolerant coliforms are assessed against risk factors obtained from sanitary surveys and wider hazard assessments. Groundwater samples were obtained from both deeper boreholes and shallow hand-dug wells located in a range of housing densities and land uses. Sampling was repeated in both the dry and wet seasons to investigate temporal differences. Preliminary results show that thermtolerant coliforms were generally absent in the deep boreholes and high in the shallow wells (10 2 -10 4