Evaluation of Physico-Chemical and Heavy Metals Concentration of Groundwater in Okrika, Rivers State, Nigeria

Groundwater is susceptible to overexploitation and pollution, causing water stress. Seawater intrusion makes coastal aquifer groundwater more vulnerable. Therefore, this study examined groundwater samples from Okrika coastal community aquifers in Rivers State, Nigeria. Standard field and laboratory methods were used to analyze physico-chemical and microbiological parameters in 10 groundwater samples from functional boreholes in the study region. The water was tested for drinking, household, and other uses. Mean values for the following parameters are shown: pH: 5.6; Temperature: 29.3°C; Turbidity: 2.1 NTU; Dissolved Oxygen: 6.6 mg/L; Biological and Chemical Oxygen Demands: 0.4 and 0.6 mg/L; Hardness: 21.2 mg/L; Residual chlorine: < 0.01 mg/L; Electrical conductivity: 52.7 μS/cm; Salinity: 25.9 mg/L; Acidity: 0.4; Alkalinity: 6.6 mg/L; Total Suspended Solids: 0.5 mg/L; Total Dissolved Solids, 29mg/L; Nitrite, < 0.001 mg/L; Chloride, 13.6 mg/L; Sulphate, 0.7 mg/L; Nitrate; 0.9 mg/L; Phosphate, 0.5 mg/L; Calcium, 0.3 mg/L; Sodium, 3.1mg/L; Iron, 0.1 mg/L; Magnesium, 0.9 mg/L; Zinc, 0.04 mg/L; Lead < 0.001 mg/L; Total Coliform,1574 MPN/100 mL; Faecal Coliform, 1510 MPN/100 mL. The parameters' values are within NSDWQ 2015 and WHO 2017 limits, except for Iron, which has a slightly high concentration, and Total and Faecal Coliform, which have high values in most of the study area. These data also suggest that the groundwater is soft, low in dissolved components, and slightly acidic. Few aquifers in the research area had salt-water incursion due to chloride levels. The water is appropriate for drinking and other domestic uses when compared to drinking water standards. Acidity of the water can be treated by base- exchange with dolomite, while iron by aeration and filtration methods. Total Coliform and Faecal Coliform treatment involve removing contamination sources, repairing systems, shock chlorinating and flushing impacted boreholes.