Rainwater quality assessment in Sefwi Dwinase, western north region of Ghana

Abstract

Rainwater is considered to be one of the reliable means of water supply to sustain life. In Ghana, there have been efforts to create awareness and interest in RWH to achieve national water coverage. However, atmospheric and other pollutions threaten its usage. This study analyzed the impact of different roofing materials on the physico-chemical, trace metals and microbial quality of rainwater in Sefwi Dwinase and how it can be efficiently put to use. Using descriptive design, twenty-one samples were taken from open environment, plain aluminium, flat concrete and colour-coated galvanized roofs. The samples were tested at the laboratory for concentrations of Total hardness, pH, TDS, DOC, EC, Calcium, Magnesium, Lead, Iron and Total coliform. The result revealed that, the physico-chemical parameters of the rainwater in the study area fell within the WHO guideline value for potability except pH which had some samples to be slightly acidic. Iron, Lead and TC had higher concentrations above WHO guideline. Plain aluminium roof is slightly advantageous over the others for RWH. Also, anthropogenic and biological factors increase trace metals and Total coliform in the rainwater. I concluded that, while the physico-chemical quality of the rainwater is good, it has trace metal and bacterial contamination. Meanwhile, with proper treatment, it can be used for potable and non-potable purposes. RWHS should be efficiently installed by authorities in institutions such as schools and hospitals in the town to augment water supply from the other sources, amidst regular cleaning of roof catchments, treatment of water and testing to monitor contaminations.