Fig. 4.

Scatter diagrams of A concentrations of Mn in hair and water and B Ni in hair and water in the black shale area at Sotkamo (n = 45), C concentrations of Mn in hair and Ni in water and D Ni in hair and Mn in water in the reference area at Sotkamo (n = 17), and E concentrations of Ni and Mn in hair, and F Ni in hair and water in the black shale area at Kaavi (n = 19). The study areas are rural and pristine, and sparsely populated