Scientists have discovered the presence of contaminants in the pelagic food chains in the lakes Mjøsa, Randsfjorden and Femunden in Norway, and in supplementary material of fish from Tyrifjorden and Vansjø, sampled in 2015. Mercury and persistent organic pollutants (cVMS, PCBs, PBDEs, PFAS) were analyzed in samples of fish from all lakes, as well as pelagic crustaceans in Mjøsa.