2.2. Water/sediment incubation experiment Three batches of sediments were collected from two rivers in Germany, i.e. Roter Main upstream and downstream of the city of Bayreuth, and Gründlach downstream of the city of Herolds-berg. Artificial river water was prepared in the laboratory (seeSupplementary Material for details). The composition of the water was adapted to the aquatic chemistry of the river Roter Main. Allincubation experiments were conducted in 1 L glass bottles whichwere