Water Quality Considerations in Rainwater Harvesting Case Study of Heavy Metal Contamination in Kampala City

Past studies have established a link between industrialization and heavy metal contamination of rainwater. However, no such study has been done in Kampala, or elsewhere in Uganda. In view of industrialization and the proliferation of iron roofs, this study aimed at addressing the suitability of rainwater harvesting and its quality as an alternative source of drinking water supply. The specific objectives were; to identify the predominant roof-covering materials in use in Kampala; to determine the level of heavy metal contamination obtained from each of these roof materials; and to compare the quality of water obtained, with various accepted standards for drinking water. The roof coverings considered were clay tiles, plain Galvanized Corrugated Iron (GCI) sheets and painted GCI sheets. In each of these types, they were further classified as relatively new, medium age and the relatively older. Samples were collected from each of the five divisions, including a control sample that was intercepted directly from open space. In the laboratory, heavy metal tests were performed on these samples, using a Flame Atomic Absorption Spectrophotometer. The metals tested were Cadmium, Copper, Lead, Zinc and Nickel.