Occurrence of a Polychlorinated Biphenyl (PCB) Congener in Surface Water, Sediments and Blackchin Tilapia ( Sarotherodon melanotheron  ) from Ologe Lagoon, Nigeria

Polychlorinated biphenyls (PCBs) are persistent organochlorine chemicals that are toxic to aquatic organisms and humans. PCBs levels were assessed in surface water, sediments and fish from Ologe Lagoon, a major water body receiving treated effluents from Agbara Industrial Estate, using Gas Chromatograph-Electron Capture Detector (GC- ECD). 2,4,4’-Trichlorobiphenyl (2,4,4’-TCB) was the only PCB congener detected in the assessed matrices. Sediment 2,4,4’-TCB levels ranged from 0.0033±0.00333 to 0.0430 ± 0.00351ng/g. There was a significant (p < 0.05) seasonal variation in the levels in sediments and surface water. The level in surface water from Zone 3 was above USEPA’s safe limit (0.0005 mg/L) in the rainy season. There was no significant (p > 0.05) seasonal difference in the mean concentrations of 2,4,4’-TCB in fish, and the levels were lower than WHO’s safe limit (0.2 mg/kg). Based on the negligible to low levels of 2,4,4’-TCB in S. melanotheron inhabiting the lagoon, the fish was considered safe for consumption. Levels of 2,4,4’- TCB found in the sediments and surface water in this study indicate that levels may change with season, therefore, we recommend that the concentrations of the compound are regularly monitored in order to timely avert toxic levels of bioavailable 2,4,4’-TCB in the water body.

Keywords
Polychlorinated biphenyls; Sarotherodon melanotheron; Sediments; Surface water