Preliminary Assessment of Water Quality in Some Hydrocarbon-imparted Ogoni Communities in River State, Nigeria

Aim: This study aimed to assess the quality of drinking water in some hydrocarbon-impacted Ogoni communities.

Study Design: The study employ a cross-sectional and analytical design using stratified sampling method.

Place and Duration of Study: Department of Medical Laboratory Science of Rivers State University, Giolee Global Resource Limited and Environmental Consultancy Services between March 2020 and March 2021.

Methodology: Water samples were collected from (20 hydrocarbon- impacted communities) in the 4 Local Government Area (LGAs) of Ogoni land. These water samples were analyzed to determine the physicochemical, bacteriological, heavy metal and total petroleum hydrocarbon (TPH) parameters using standard methods and operational procedures. The data obtained were subjected to descriptive statistical analysis. The general linearized model (GIG) was used to generate analysis of variance (ANOVA) mean and standard error and arrange, statistically significant was set as p-value of .05 (95% confidence limit). Pearson correlation test was used to calculate the correlation between TPH, Heavy metal, and physicochemical parameters in hydrocarbon and non-hydrocarbon impacted communities. All statistical analyses were performed using GraphPad Prism (Version 8).

Results: The results obtained for physicochemical parameters were pH 4.3±0.8 mg/l, EC 0.03±0.05 mg/l, DO 5.5±1.6 mg/l, Temp 25.0±0.0 mg/l, Mv 0.32±0.27 mg/l, Nitrite 0.0058±013 mg/l, Nitrate 0.1530±158 mg/l. These results were all below the recommended standard for Nigeria standard of drinking water quality (NSDWQ) and World Health Organization (WHO). The bacteriological analyses were carried out using multiple tubes technique (Most Probable Number), total coliform count, (TC), total heterotrophic count (THBC) and total fungal count (TFC). The results obtained were 0.941±2.397 cfu/ml, 89.3±176.6 cfu/ml, 297.8±144.4 cfu/ml, and 0.32±0.84 cfu/ml respectively. The p-values for TFC (<0.0002) were statistically significant. Heavy metal profiling was: Cr 0.194±0.320 mg/l, Cd 0.469±0.569 mg/l, Cu 0.211±0.348 mg/l, Pb 0.0336±0.20 mg/l, Fe 0.705±1.244 mg/l, Zn 0.258±0.249 mg/l, respectively. Generally, the concentration of heavy metal increased more than the standard recommended by NSDWQ and WHO except for Zn 0.255±0.249 mg/l, and Cu 0.56±0.50 mg/l, that is slightly lower than the acceptable limit recommended by WHO and NSWWQ. The sequences of heavy metal concentration were in Cd > Cr> Pb>Fe> Cu.>Zn. The statistical significance values for Pb p=.003 and for Zn p=.009 were statistically significant. The concentration of TPH were (349.9 ppm/ml) higher than the recommended values for NSDWQ and WHO.

Conclusion: The findings in this research reviewed a worrisome level of TPH and Pb, and which could have devastating impact on bacterial biodiversity.