Hydrogeochemical and Biophysical Characterization of Groundwater in Eastern Nigeria: A Case Study of Onitsha and Environs

Abstract

Hydro-geological studies revealed that Onitsha and environs tapped their groundwater from the middle aquifer (> 40 m < 90 m)which belongs to the Ameki group; hence, water samples from ten (10) wells in areas of high population density namely Okpoko, Fegge, main market, GRA phase 1, Inland town, Nkpor, Obosi, Awada and Mgbemena on 6049’30”E and 608’830”N were collected for biological and physiochemical analysis in order to determine its quality for consumption by comparing with established standard of World Health Organization. The samples were analyzed using standard methods. The Coliform counts result showed a range of 1 to 30MPN/100MI while heavy metal value shows that Fe > Zn > Mn > Ba > Cu. The results for the major cations analyzed shows a mean value of Na+ (3.32 mg l-1), K+ (0.8mg l-1) Ca2+ (8.62 mg l-1), Mg2+ (2.57mg l-1), Temperature, pH, Total Dissolved Solid (TDS) and Electrical Conductivity (EC) where measured in situ, major anions where also analyzed and the results shows that the mean value for HCO3- (61mg l-1), PO43- (61.5 mg l-l), NO3- (21.6 mg l-1) , SO42- (99 mg l- 1), while Cl- (450 mg l-1), Correlation at P < 0.05 using micro soft excel 2007shows that metals assessed were from similar source. The ultimate result when compared with World Health Organization shows that the groundwater of the middle aquiferous horizon in Onitsha and environ in Eastern Nigeria is polluted in some areas covered in this research and not fit for consumption except when treated appropriately.