Polychlorinated biphenyls (PCBs) in water and sediments from the Udu River, Niger Delta, Nigeria: concentration, distribution and risk assessment

Abstract

In this study, five surface water and sediment samples were collected from five different points along the course of the Udu River, Niger Delta, Nigeria, which were near the human population. Water samples were liquid-liquid extracted with dichloromethane in a separatory funnel, while sediment samples were Soxhlet extracted using a mixture of acetone, dichloromethane, and n-hexane. Quantification of polychlorinated biphenyls (PCBs) in the extracts was done using gas chromatography-mass spectrometry. The ecological risk of PCBs was assessed by comparing the determined PCB concentrations with established guideline values, while health risk was evaluated using non-cancer and total cancer risk models. From the results obtained, only one congener (PCB-167) was present in water samples, with concentrations ranging from 20-1860 ng L-1. For sediment samples, 28 congeners were detected. The concentration of Ʃ28PCBs and the 12 dioxin-like PCBs (dl-PCBs) ranged from 5.34-16.1 and 1.07-5.36 ng g-1, respectively. The toxicity equivalence values for dl-PCBs varied from 0.0065-0.018. Compared to guideline values for both water and sediment, the PCB concentration obtained in this study does not pose any ecological risk at all except for one sampled point. Similarly, the hazard index values for non-cancer risk evaluation were < 1 at all but one point, while total cancer risk values were between 1 × 10-6 and 1 × 10-4 at all but one sampling point, indicating no potential risk of developing cancer associated with PCBs in water and sediments of the Udu River.

Health risk assessment of polychlorinated biphenyls exposure from inland rivers sediments in Warri-South, Warri, Delta State

“…The concentration of 16 PCBs were also discovered as non-dioxin-like PCBs which are PCB8, 18, 28, 44, 52, 66, 101, 128, 138, 153, 170, 180, 187, 195, 206 and 209 and they ranged between 0.18 -386.47 ng g -1 for Ugbuwangue river sediment, 0.13 -111.98 ng g -1 for Ugbori river sediment and 0.31 -4245.71 ng g -1 for Edjeba river sediment. Polychlorinated biphenyls are extremely carcinogenic compounds that may be present in industrial and consumer foodstuffs [21]. A comparison of ∑28 PCBs concentrations in river sediments studied with others reported for river sediment in literature are shown in Table 4.…”

Study the regional and seasonal variation of polychlorinated biphenyl in sediments of the Eastern AL-Hammar Marshes, Iraq

“…At the apex of the food chain, they biomagnify, including humans. (Kelly et al, 2007;Iniaghe and Kpomah, 2022).…”