Manganese concentration analyses
We explored Mn accumulation to better understand the effects of Mn exposure on fish. Single organs (e.g., liver, brain) were too small to provide sufficient dry weight for Mn detection. Instead, we focused on the head (e.g., brain, gills) and the rest of the body (e.g., liver, muscle tissue), i.e., we used two samples per fish in the analyses. Samples were freeze dried for 48 hours (Christ Alpha 2–4), smashed and digested in aqua regia (HNO3:HCl 1:3). Then, the digested tissue samples were filtered and filled to a final volume of 10 ml with ultrapure water, after which the samples were analyzed similarly than the water samples with Perkin-Elmer Avio 500 ICP OES.