Heavy metals (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, V and Zn) were analysed at ALS Scandinavia AB using a mass spectrometer and the organic chemistry (δ¹⁵N, δ¹³C, TN, TOC and C/N) analysis was conducted at the University of Gothenburg using a SerCon isotope ratio mass spectrometer, both from freeze-dried sediment samples. The environmental variable units are as follows: metals are all (mg/kg), TN (ppm), TOC (mg/L). C/N, δ¹⁵N and δ¹³C have no units as they are isotope ratios.