Scientific African (Nov 2023)
Source apportionment of polychlorinated biphenyls in surface water and sediments from River Otamiri, Imo State
Abstract
Polychlorinated biphenyls (PCBs) are a group of toxic, long-lasting substances that have a high propensity to accumulate in the environment as organic pollutants which can cause potential risk to the environment. In this regard, the concentration and sources of PCBs in the surface water and sediment of River Otamiri in Imo State was investigated. This study collected surface water and sediment samples from River Otamiri at four sampling points. It was analyzed for PCBs concentration using an Agilent 7890A gas chromatograph coupled to an Agilent 5975C mass selective detector. Twenty-eight PCB congeners were detected in the water and sediment samples. Also, the PCB congeners' descriptive statistics (mean and standard deviation) in the studied matrices were reported. The concentration of PCB congeners for the surface water and sediment ranged from 622.87–935.84 ng L−1 and 1621.03–2748.17 μg kg−1 respectively. The concentration of PCB congeners in the studied matrices revealed that PCB-118 had the highest concentration, while the lowest concentration was recorded in PCB-157. Statistical methods were used to identify the source of the pollutant in the studied matrices. Pearson's correlation coefficient for PCBs in sediment and surface water samples was calculated, and the results revealed that all the sampling points showed a strong and positive correlation with each other, indicating a similar origin/source. Based on this study's findings from principal component analysis (PCA), the origin/source of the pollutant was similar and was attributed to geogenic factors such as the leaching of soils from waste dumpsites and auto-mechanic workshops around the River Otamiri. In addition, ANOVA of PCBs in the surface water and sediments revealed a p-value less than 0.05 in all the studied matrices. The study's findings suggest that using statistical methods can give a scientific basis for monitoring and determining the source of polychlorinated biphenyls in surface water and sediments. In conclusion, government agencies are to develop environmental policies and framework that will guide and protect the environment from organic pollutants (PCBs) that will pose risk to the surface water and sediments of rivers.
