Abstract

Polychlorinated Biphenyls (PCBs) are a class of the persistent organic pollutants (POPs) with long-range transport, and the ability to bioaccumulate and biomagnify through the food chain. Seventeen PCBs were analysed in sediment samples collected from six stations in the Lagos lagoon. Using a Van Veen grab sampler and stored in glass bottles following standard procedures. Cleaned extracts were analysed using a Gas Chromatograph interfaced to a Mass Spectrometer (GC-MS) equipped with an Elite-5MS (5% diphenyl/95% dimethyl polysiloxane) fused with a capillary column (30 × 0.25μm ID × 0.25 μm df). The mean concentration of PCBs in sediment samples ranged from 0.093 mg/L in Unilag lagoon front to 2.626 mg/L in Okobaba sampling stations. Analysis of variance showed that there is no significant difference (P>0.05) in the mean PCB concentrations across the stations. The number of low-chlorinated PCB homologues (∑di-PCB - ∑penta-PCB) detected in this study dominated in occurrence with 99.23% while the high-chlorinated ones (∑hexa-PCB - ∑nona-PCB) showed only 0.77% occurrence. These research findings indicate that PCB congeners have been introduced into the Lagos lagoon from anthropogenic sources. Their lipophilic nature, and persistence in the sediment could pose serious ecological and health risks especially as some of the benthic macroinverbrates, which live at the sediment are sources of food to higher organisms and man. There is need for constant monitoring of the lagoon.