Polychlorinated biphenyls in sediments and fish species from the Murchison Bay of Lake Victoria, Uganda

Abstract

• High concentrations of PCBs were found at sites near wastewater discharges.• The PCB concentrations were low to moderate compared to other locations worldwide.• Based on the European Commission set TEQ, the fish were fit for human consumption. Polychlorinated biphenyls (PCBs) were determined in sediments and two fish species collected from the Murchison Bay in Lake Victoria, using high resolution gas chromatography coupled to a high resolution mass spectrometer. Total PCB concentrations (Σ 18 PCBs) varied widely with mean values ranging from 777 to 4325 pg g −1 dry weight (dw) for sediments and 80 to 779 pg g −1 wet weight (ww) for fish. The PCB levels in the sediments were significantly higher at the station closest to Nakivubo channel, presumably due to effluents discharged by the channel, which may contain domestically produced commercial PCB mixtures. For fish, the concentrations in Nile perch (Lates niloticus) were significantly greater than those in Nile tilapia (Oreochromis niloticus) at all study stations, possibly due to dietary differences among species. World Health Organization-toxic equivalents (WHO 2005 -TEQs) for the dioxin-like PCBs were 0.04-0.64 pg g −1 dw and 0.01-0.39 pg g −1 ww for sediments and fish, respectively. The non-ortho PCBs exhibited the highest contribution to the Σ 12 TEQs (N75%) compared to the mono-ortho PCBs in both fish species. The TEQs in the present study were lower than many reported worldwide in literature for fish and were within the permissible level recommended by the European Commission, implying that the fish did not pose health hazards related to PCBs to the consumers. a b s t r a c t a r t i c l e i n f o

PCBs in fish and their cestode parasites in Lake Victoria

“…The concentration of Σ7PCBs in sediments were higher than those measured in River Pangani, Tanzania (1.3-7.0 μg/kg dw; Hellar-Kihampa et al 2013), Murchison Bay, Lake Victoria, Uganda (0.41-4.652 μg/kg dw; Ssebugere et al 2014b), and Pearl River Delta, South China (0.43-1.77 μg/kg dw; Wang et al 2011). These values were also consistently very high compared to River Congo, DRC (<0.005-0.65 μg/kg dw; Verhaert et al 2013), in the Napoleon Gulf of Lake Victoria, Uganda (0.04-1.02 μg/kg dw; Ssebugere et al 2014a), and those from Guanabara Bay (0.018-0.184 μg/kg dw; de Souza et al 2008).…”

Persistent Organochlorine Compounds Levels in Selected Fish Species from Lake Victoria and Associated Human Health Risks

“…Lake Victoria is a trans-boundary lake shared between Tanzania (51%), Uganda (43%) and Kenya (6%). It is the World's second largest lake with the approximated total surface area of 68,800km 2 after Lake Superior of North America [9,10]. The lake supports one of the World's most productive inland species of fisheries of commercial value such as Nile perch, Nile tilapia, and other species.…”

“…The lake supports one of the World's most productive inland species of fisheries of commercial value such as Nile perch, Nile tilapia, and other species. The highly caught and consumed fish species at international and domestic markets are Nile perch (Lates niloticus) and Nile tilapia (Oreochromis niloticus) respectively [9,10].…”

“…Though the age of fish was not determined, previous studies have reported that the length of fish is directly related to its age and that age has great influence on the bioaccumulation of the investigated organochlorinated compounds in fish [6]. And the longer the fish lives in a contaminated aquatic environment, the more the organochlorine compounds it accumulates; this is because the available evidence shows that organochlorine compounds tend to biomagnify with time [9,23,24].…”

“…Evidence shows that PCBs have stopped been produced worldwide since 1984; however, several PCB containing materials have been used much longer. However, studies in countries that are sharing Lake Victoria with Tanzania namely, Uganda and Kenya have reported significant quantities of PCBs in water, sediments, and in fish [9,10,11]. The compounds are reported to be semi-volatile and this nature has enabled them to move longer distances in the atmosphere before they are finally deposited in the environmental compartments [12].…”