EVALUATION OF BOREHOLE WATER QUALITY IN GASHUA, YOBE STATE, NIGERIA

Abstract

Water is one of the valuable natural resources whose quality and quantity has vital concern for the human welfare. The study evaluated the water quality (bacteriological and physicochemical parameters) of twenty (20) selected boreholes in Gashua, Yobe State. The percentage (%) efficiency of yield for the twenty (20) boreholes analysed ranges from 16.1% to 99.5%, the least being observed at Takari location (GB19), while the highest at Kabalankara location (GB8); within this range, 85% of the boreholes were producing below 50% efficiency and 15% produce above. The results of the pH values of 20% of the water samples from the boreholes studied ranges from pH 6.50 to 6.82 which are within the NSDWQ maximum permissible limit, while the pH of 80% of the water samples ranges from pH 5.84 to 6.42 which were more acidic and below NSDWQ permissible limit. The heavy metal contamination of water samples shows 100% of the samples contained As, Cd, Hg above, Fe within NSDWQ maximum permissible limits, while Pb was not detected in all the samples analysed. The result of total coliform tests ranges from 0.00 to 4.0 CFU/100ml, which indicated 100% the samples passed NSDWQ maximum permissible limit, while E. coli test result range from 0.00 to 3.0 CFU/100ml from which only 20% of the samples (Takari, Fada, Karamintanda and Yusufari Road) passed the NSDWQ maximum permissible limit. Other physicochemical parameters such as electrical conductivity (EC), total dissolve solids (TDS), total hardness (TH), nitrate (NO3-), sulphate (SO4-), chloride (Cl-), Magnesium (Mg) and calcium (Ca) ranges as 0.06 – 0.25 µs/cm; 0.04-0.13 mg/L; 0.72-1.01 mg/L; 1.99-31.55 mg/L; 13.98-37.61 mg/L; 2.07-24.07 mg/L; 0.13-1.06 mg/L and 0.65-2.59 mg/L respectively, all passed the NSDWQ maximum permissible limit. The observed causes of low yield could be due to Hydrogeological, technical/constructional and operations/maintenance factors. Presence of heavy metals and bacteriological contamination could be attributed to the agricultural activities such as irrigation farming which involve use of waste water, chemical fertilizer and other agrochemicals. Traditional potash mining activities which warranted for littered faecal deposits in the area by the miners and the irrigation farmers could be linked to the bacteriological contamination of some of the water samples. The need to deploy expertise by State and local government council in the affected areas will alleviate the situation and adequately supply portable water that can meet the demand of the increasing population of the area.