Polychlorinated Biphenyls in Brackish Water Fish in the River Niger, Nigeria

摘要

Background. Anthropogenic polychlorinated biphenyls (PCBs) in aquatic environmentsposes human and ecological health risks in Nigeria.Objectives. This study determined the concentrations of PCBs in brackish water fish in theRiver Niger to assess the contamination status of fish consumed by the local population.Methods. The sampled fish species included Drepane africana, Mochokus niloticus,Chrysichthys nigrodigitatus, Pristipoma jubelini, Vomer septapinis, Pseudotolithussenegalensis, Mugil cephalus, Pseudotolithus elongatus, Sphyraena piscatorum and Lutjanusgoreensis, purchased from landing sites. Six fish from each species were sampled, for a totalof 60 samples. Twenty-seven (27) PCB congeners, #8, #18 #28, #44, #52, #60, #77, #81, #101,#105, #114, #118, #123, #126, #128, #138, #153, #156, #157, #167, #169, #170, #180, #185,#189, #195, and #206 were screened in the fish samples using standard methods. The PCBswere identified and quantified using gas chromatography (GC) (Hewlett Packard GC 5890series 11 with electron capture detector). Confirmation was performed using ShimadzuGCMS QP2010.Results. The sum of the National Oceanic and Atmospheric Administration Agency(∑NOAA) PCBs occurred at the highest concentration of 1830.0±484.0 μg/kg detected inVomer septapinis, and the lowest in Pseudotolithus senegalensis, with a mean concentrationof 795±169.3 μg/kg. The concentration of dioxin-like (DL) PCBs was highest in Pristipomajubelini (992.0±88.6 μg/kg) and lowest (285.6±81.5 μg/kg) in Drepane africana. The highestmean concentration (418.±177.6 μg/kg) of International Council for the Exploration of theSeas-7 (ICES-7) PCBs was observed in Vomer septapinis. The heavier ICES-7 congenersPCB-138, PCB-153, and PCB-180 occurred at higher concentrations compared to the lightermolecular weight ICES-7: PCB-28, PCB-52, and PCB-101. The European Union (EU) markerPCB limit of 335 μg/kg was exceeded in all the brackish water fishes with the exception ofMochokus niloticus, Pristipoma jubelini and Pseudotolithus senegalensis.Discussion. The total level of PCBs in the brackish fish samples was relatively high at 1000μg/kg (above the World Health Organization (WHO) and Food and Agriculture Organizationof the United Nations (FAO) guideline of 1000 μg/kg fresh weight). The EU guideline valuefor fish (220 μg/kg fresh weight) was exceeded in about 80% of the brackish fish samplesstudied.Conclusions. Consumption of fish from the River Niger may expose humans topolychlorinated biphenyls. In addition, since contamination of the fish samples is anindication of river contamination, river water quality is of great concern and there is a needfor additional PCB data on water quality to be distributed to the community, followed bymitigation measures.Competing interests. The authors declare no competing financial interests.