ABSTRACT 

Physiochemical and bacteriological analyses of water samples from three different boreholes located close to a dumpsite at Owerri, Nigeria were carried out to evaluate the level of dumpsite pollution on underground water. Some soil hydraulic properties were analyzed to determine the penetration rate of leachate into the underground water. Borehole locations were at distances of 50m, 100m, and 500m respectively away from the dumpsite. The parameters determined included; turbidity, temperature, pH, chemical oxygen demand (COD), total dissolved solids (TDS), Total Hardness (TH), Total  Iron, Nitrate, Nitrite, Chloride, Calcium and some metals such as Copper, Zinc and Lead using standard laboratory equipment and procedures. Most of these parameters indicated slight pollution but below the Nigerian Standard for Drinking water quality (NSDWQ) and World Health Organization (WHO) limits permissible for consumption. The pH and turbidity values of 6.95 and 3.5 NTU respectively were obtained indicating the presence of active microorganism. Temperature was peaked at 27.8⁰C. The concentrations of COD, TDS, and TH were highest at 2.2mg/L, 352mg/L and 150mg/L respectively. The maximum observed concentrations of calcium, nitrate, nitrite and chloride were 75mg/L, 56mg/L, 1.1 mg/L and 193mg/L respectively. The metals iron, lead, zinc were peak at 4mg/L, 0.1 mg/L and 0.1mg/L respectively, while copper was only detected in one site with maximum value of 0.2mg/L. Bacteriological analysis ranged from 0-50/100ml MPN for all the boreholes. For soil hydraulic properties the maximum values obtained were as follows; soil infiltration rate (I.R) - 5.6 cm/hr., soil bulk density-1.2 g/cm³, cation exchange capacity (C.E.C.)-1.1% and effective porosity (E.P)-65%. Statistical analyses indicated significant differences in all the parameters tested for, in the samples at (p<0.05) compared to WHO and NSDWQ standards. The results showed that underground water from site 1 and 3 was slightly polluted but still require certain levels of treatment before use while that of site 2 at Aba road was highly polluted and such needed to be thoroughly treated before use. Therefore, the use of advanced water treatment technology and water purification methods such as sedimentation, filtration, distillation and chlorination of drinking water before consumption to prevent infections are recommended also adequate public enlightenment on proper waste disposal management, treatment and siting of boreholes far away from dump sites are encouraged.