Physico-chemical and Bacteriological Assessment of Groundwater from Peri-urban Area of Douala – Cameroon

Abstract

The physicochemical characterization of water of the peri-urban area of Douala city was carried out from 04 springs and 21 wells in February 2013 and August 2013 corresponding to the dry season and the rainy season respectively. For bacteriological analyzes, thirteen water points were sampled, including 4 sources, 08 wells in the rainy and dry season. All the water points yielded pH values below 7,0 and were classified as acidic water. Electrical conductivity ranged between 44.30-483μm/cm and then waters are poor mineralized. The relative abundance of major ions (mg/l) was Ca2+> Na+> K+> Mg2+ for cations in dry season whereas and Na+> K+> Ca2+>Mg2+ in the rainy season. For the anions, HCO3-> Cl->SO42-> NO3- in the dry season whereas in the rainy season HCO3- > Cl- > NO3- > SO42-. Major ion concentrations were within the WHO guidelines for drinking water, but a few points have a concentrations below the WHO limits. Main water types in the both seasons were Ca-Mg-HCO3 and Ca-Mg-Cl. Bacteriological analysis revealed that all water points sampled during the rainy season and some (67%) during dry season contain feacal contamination control germs. Bacteriological contamination of the water is of human and animal origin. Human origin is linked outflow from latrines used by the population. The spring and well waters analysed are not suitable for drinking and domestic purposes except two springs in the dry season.