Temporal water quality study of the heavily human-impacted Likangala River, Zomba, Malawi

Abstract: River water is used for a range of purposes, for example irrigation, laundry, hygiene, mining of sand, as drinking water and for disposal of wastes and wastewater. These anthropogenic activities, along with agriculture and the local climate and geology will have effects on the water quality, and by extension the people living in the area. This study intends to evaluate the water quality of Likangala River, which is a perennial river in southern Malawi, during hot dry season linking it to the activities present in the direct vicinity of the urban segment of the river. A small land use survey was carried out, and eight points for water sampling chosen for analysis of a set of physio-chemical water quality parameters. Also an estimate of the water discharge of the time was made. It was found that most parameters were within the guidelines for drinking water set up by WHO (2011) and Malawi Bureau of Standards (MBS, 2008), although turbidity, manganese, iron, chromium and lead showed elevated levels. Some, but not all, parameters showed a trend with low values upstream the city and higher values downstream (except pH with a inverse trend), and almost all parameters were significantly higher in the effluents from the Zomba Sewage Works, and also directly afterwards.