Authors: Umbugadu, A.A. and Akinwumi, T.V.
Abstract
The release of wastes generated from the activities at automobile workshops leads to heavy metals contamination of groundwater which can be harmful to human health. The study is aimed at investigating the physicochemical and
heavy metal contamination of groundwater from three automobile workshops at Super, Jankara and Kola areas located at Alimosho, Ifako – Ijaye and Agege Local Government areas of Lagos State. Fifteen (15) samples were collected from residential houses near the automobile workshops, at 5m – 75m depth and taken to Federal Institute of Industrial Research (FIIRO) laboratory at Oshodi, Lagos. Electrical conductivity (EC), pH, temperature and total dissolved solids (TDS) were measured onsite using a 107 model pH meter. The samples were analysed for lead, magnesium, manganese, cadmium, arsenic, chromium and mercury using Atomic Absorption Spectroscopy; Perkin Elmer model Analyst 3000.The TDS value of all the samples in this research ranged from 0.017 mg/l – 0.097mg/l which is within the W.H.O. standards of 500mg/l. The pH value of all the analysed groundwater samples ranged from 4.4 – 7. This implied that groundwater in the study area are slightly acidic to neutral. The groundwater samples from JW03 are below the acceptable pH limit of W.H.O while the groundwater from the remaining 14 sampling points have pH values less than 6.5, hence, they are slightly acidic. Only two sampling points in Jankara; JW06 and JW07, falls within the W.H.O acceptable limit while the remaining samples have values lower than 6.5. The electrical
conductivity in the water analysed ranged from 0.72 μS/cm – 194 μS/cm. The electrical conductivity value of all the water samples analysed are below the W.H.O standard of 1000μS/cm. This result reflects a low input of solute in the groundwater. The temperature values of the groundwater samples of the three areas of the research ranged from 26.8 ºC – 37.8ºC with a median value of 30.2ºC. The values exceeded that of W.H.O limit of 25ºC. The concentration of heavy metal in groundwater of the three mechanic workshops are in this trend; Pb>Mn>Cd>Cr. Arsenic was not detected in all the groundwater samples from the three mechanic workshops. The metal Pb have a range of 0.382 mg/l – 1.895mg/l and an average of 1.070mg/l, Mn ranged from 0.067 mg/l – 2.0933mg/l with an average of 0.7468mg/l, Cd ranged from 0.146 mg/l – 0.5937mg/l with an average of 0.36mg/l while Cr ranged from 0.036 mg/l -0.098mg/l with an average of 0.060mg/l.