Fig. 3

Development of sediment concentrations in ng/g d.w. of different persistent organic micropollutants in various mountain lakes of the world over time. Development of A ∑PAH concentrations, B ∑PCB concentrations and C ∑DDT concentrations. Vertical lines represent points of reference and show average concentrations of the 1970s and − 90 s in lakes of the U.S. in urban (dashed line), light urban (dotted line) and remote areas (solid line) (Additional file 1: Table S2)