The physicochemical properties and the concentrations of heavy metals of water samples collected from four different rivers of Nkanu east and west Local Government Areas of Enugu of state Nigeria were investigated because of the prevalent water borne diseases in these localities attributable to the drinking of contaminated water. The water samples were collected from different sites of Esu, Umuekwe, Umuobeagu and Atafu rivers and their physicochemical properties and heavy metal contents were measured. Sampling Stations were selected; samples were collected avoiding contamination from the selected sites in same season, from same depth. On site measurement of parameters was done with the same instruments. Rests of the parameters were measured in Laboratory. Lead (Pb) was present in Esu, Umuekwe, Umuobeagu and Atafu rivers at a concentration of 0.14, 0.03, 0.00 and 0.16 mg/L respectively; Zn was only detected in Esu and Umuobeagu at 0.07 and 0.01 mg/L respectively and cadmium (Cd) concentrations of 0.14, 0.14. 0.08 and 0.08 mg/L respectively. Iron was detected in only Umuekwe river having 0.17 mg/L and Atafu river having 0.21 mg/L while Ni was detected at 3.01, 4.20, 1.20 and 3.83 mg/L respectively. Only Atafu river had Cr at 0.01 mg/L, only Esu river had Co content at 0.05 mg/L, Mn content in Esu, Umuekwe, and Umuobeagu was found to be 0.01, 0.02 and 0.02 mg/L respectively with Atafu river having none. Hg concentration was found to be 0.57, 0.06, 0.42 and 0.82 mg/L for Esu, Umuekwe, Umuobeagu and Atafu rivers respectively. The concentrations of Pb and Cd were higher in all the four samples especially in Esu river as a result of its closeness to construction sites and refuse dump and the concentrations were above the acceptable limits of WHO standard of 0.010 and 0.005 mg/L respectively for drinking water while Hg, Fe, and Ni were found within the W.H.O limits of 0.001, 3.000 and 0.100 mg/L respectively. The rest were below the standard, thus confirming conclusively that the rivers are polluted with the presence of heavy metals.
Physicochemical characteristics and green microalgae composition of selected rivers in Ogun State, Nigeria
