The Groundwater Research Group at Queens University Belfast (QUB) focuses on hydrological contaminant pathways, fractured rock, poorly productive aquifers and wetland hydrology/hydrogeology. Colleagues in the QUB Environmental Engineering Research Centre research arsenic remediation and groundwater management in the Indian sub-continent. Collaborative research undertaken by Groundwater Research Group staff has direct applications for improving water quality in sub-Saharan Africa and other developing nations.
Despite improvements in water treatment over the past century, potable water supplies contaminated with pathogenic micro organisms (pathogens) continue to cause sporadic waterborne disease outbreaks across the developed world. Fortunately, such occurrences remain rare. In the developing world, by contrast, such incidences are far more common, with microbiological contamination of water supplies being responsible for an estimated 2.2 million deaths annually.
To better understand the mechanisms by which urban groundwater supplies become contaminated in developing countries, a hydrogeological investigation of groundwater discharging from a large urban spring in Kampala, Uganda was undertaken by Dr. Raymond Flynn (Queen’s University Belfast), Dr. Richard Taylor (University College London), Dr. Robinah Kulabako (Makerere University, Kampala) and Ms. Marion Miret (University of Neuchatel). The study aimed to explain water quality by monitoring spring discharge, along with the chemical and microbiological characteristics of spring water.
Study results showed that high densities of pit latrines in the immediate vicinity of the spring could be associated with elevated nitrate levels (130 mg/l) and chloride (56 mg/l). By contrast indicator micro-organism levels, reflecting pathogen contamination, were not detected in spring discharge during the dry season. Laboratory-based batch tests and column tests of lateritic subsoil, comprising the uppermost layers of the saprolite aquifer that supplies the spring, indicate an exceptionally high capacity for adsorbing and inactivating (killing) bacteria and viruses. The findings explained why incidences of water borne disease among spring water users remained low outside the wet season. Currently studies are under way to examine the possibility of using laterite as part of an inexpensive intermediate technology treatment system for domestic water supplies.
Further details of the hydrogeological study can be obtained in the journal Soil, Air and Water Pollution (June 2012, Volume 223, Issue 5, pp 2405-2416).