Microbiological quality and metal levels in wells and boreholes water in some peri-urban communities in Kumasi, Ghana.

摘要

Many communities in Kumasi, Ghana, are increasingly dependent on boreholes and hand dug wells. The aim of this study was to examine the drinking water suitability of 6 wells and 3 boreholes in periurban communities in Kumasi, between December 2003 and January 2005. Total coliforms, faecal coliforms and enterococci were enumerated using the standard most probable number method and membrane filtration methods. The heavy metals in the water samples were determined using the atomic absorption spectrometry method. Overall, significantly higher bacterial counts were recorded during the wet (rainy) season compared to the dry (harmattan) season. Faecal coliforms counts (FCC) in 3 borehole samples ranged between 3 x 101 and 3.5 x 107 per 100 ml (geometric means 1.82, 1.75 and 2.8 x 104) while mean numbers of enterococci were 103-105 times lower. The range and geometric means of FCC was similar in samples from wells but levels of enterococci were 8 times higher than in boreholes. Manganese and iron levels were well within the WHO standards for all 9 sites but lead levels except for one site (Boadi) were all higher than the WHO standard. A brief sanitation survey at each site suggested that wells and boreholes were frequently cited near latrines, refuse tips and other social amenities, and in the vicinity of domestic or grazing animals. In Kumasi, the water from shallow wells and boreholes, upon which the local communities depend is of poor quality. The data are being used to advise the local government. An integrated approach is required to minimise faecal pollution of wells and boreholes within peri-urban communities.