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
Chemosphere
July 13, 2020
DOI: 10.1016/j.chemosphere.2020.127536

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.

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