Abstract

The aim of this study was to assess the physical and chemical quality of groundwater in relation to borehole location and seasonality in Chikhwawa District, Southern Malawi. A multi-stage borehole sampling procedure was used to randomly collect water samples from 20 boreholes (one sample per borehole) in triplicates. From the three main topographical areas of Chikhwawa District, ten boreholes were randomly chosen from a flood plain area, five from marshy and swampy areas and the other five boreholes from upland or high altitude areas. The samples were analysed for pH, Total Dissolved Solids (TDS), chlorides, nitrates, phosphates, sodium, iron, potassium, manganese, magnesium and calcium (pH, TDS, Cl,NO3-, PO32-, Na, Fe, K, Mn, Mg, Ca,). .The results showed significantly higher values for pH, nitrates, phosphates, chlorides, sodium, potassium and magnesium in the dry season as compared to the wet season (p <0.05). This could be attributed to the dilution factor. The levels of TDS in water samples for both seasons showed no statistically significant difference (p < 0.05). Only two boreholes recorded the presence of manganese while no borehole recorded the presence of iron in the water samples. But levels of pH, TDS, nitrates, phosphates, and chlorides (dry season only for chlorides) were above the recommended WHO and MS Maximum Contaminant Limits (MCL). For the cations, sodium is the most abundant with a decreasing trend of Na>Mg>Ca>K. Levels of nitrates, chlorides, sodium, calcium and magnesium showed spatial variation with boreholes in flood plain areas showed higher levels than boreholes in higher altitude/ basement complex aquifers.

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School	: School of Natural and Applied Sciences
Issued Date	: 2011

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