Spatial profiles of perfluoroalkyl substances and mercury in fish from northern Lake Victoria, East Africa
By Kenneth Arinaitwe, Arne Koch, Anthony Taabu-Munyaho, Karsten Marien, Thorsten Reemtsma, and Urs Berger
July 13, 2020
There is an acute deficit of data on per- and polyfluoroalkyl substances (PFASs) and mercury (Hg) in the open waters of Lake Victoria, East Africa, relative to nearshore areas. We analyzed stable isotopes (δ15N and δ13C), PFASs and Hg in Nile Perch and Nile Tilapia muscle and liver samples from nearshore and open lake locations from the Ugandan part of the lake. The δ15N values of Nile Perch muscle indicated a higher trophic level for samples from the open lake than from nearshore locations. Averages of ∑PFAS concentrations in Nile Perch muscle and liver (0.44 and 1.75 ng/g ww, respectively) were significantly higher than in Nile Tilapia (0.24 and 0.50 ng/g ww, respectively). ∑PFAS concentrations in muscle of open lake Nile Perch were significantly higher than for nearshore samples. A similar observation was made for total mercury concentrations in muscle (THg_Muscle) of Nile Perch. THg was dominated by methyl mercury (MeHg+, 22-124 ng/g ww) and mercuric mercury (Hg2+, + and some PFASs (e.g. PFOS: r = 0.704, P = 0.016) suggested similar exposure routes or factors. Estimated daily intake values of PFOS and Hg were below international limits.