Effects of industrialization on groundwater quality in Shagamu and Ota industrial areas of Ogun state, Nigeria

In recent years, there has been an increasing ecological and global public health concern associated with environmental contamination by heavy metals on groundwater resources especially in the developing countries. Hence, this study assessed the impacts of industrialization on the quality of groundwater in Shagamu and Ota industrial areas of Ogun State, Nigeria between the period of July and December 2018, covering both wet and dry season. A total of 80 samples was collected from the industrial areas while a total of four control samples was also collected from the residential areas of the study locations across both wet and dry season using a random sampling technique. The water samples were then analyzed in the laboratory for their physico-chemical parameters (using standard procedures) and heavy metals using the Atomic Absorption Spectrophotometer (AAS). The results were evaluated for descriptive and inferential statistics using SPSS for Windows version 20.0. The mean range of values for the measured parameters was: pH (4.35–9.42), EC (18.50–684.0 μScm(−1)), hardness (3.83–396.06 mg/L), Ca(2+) (0.18–138.75 mg/L) and that of heavy metals concentrations in the water sample were: Pb (0.003–0.199 mg/L), Cd (0.002–0.013 mg/L), Ni (0.004–0.259 mg/L), Cr (0.002–0.54 mg/L), Mn (0.015–1.940 mg/L), Fe (0.02–2.01 mg/L), Cu (0.012–0.72 mg/L), Zn (0.004–0.500 mg/L). A comparison of the obtained results with the World Health Organization standards (for drinking water) revealed that the levels of pH, Ca, Pb, Ni, Mn, Fe, Cd, and Cr were higher than the prescribed values. It was observed that groundwater sources for the dry season in both Ota and Shagamu have higher heavy metal concentrations that are above the permissible limits than the wet season, implying that more industrial activities were probably conducted during the dry season under the sampling period. The result of the heavy metals was in the magnitude according to the trend Fe > Mn > Cu > Cr > Zn > Ni > Pb > Cd. This study revealed that these industrialized areas contained high concentrations of heavy metals which can cause health disorders and behavioral defects. Thus, the water in the study locations is not suitable for consumption without prior treatment. It is therefore, recommends that the water in the study locations should be treated before were used for various domestic purposes, and the construction of the boreholes and dug wells are proposed here to follow proper siting regulations.