High-Resolution Pollution History Since the nineteenth Century Reconstructed from the Grietherorter Oxbow, Lower Rhine River (Germany)

The Rhine River is among Europe's most anthropogenically influenced and industrialized river systems, with persistent organic pollutants (POPs) accumulating in fluvial sedimentary archives over centuries. This study reconstructs a high-resolution pollution history from the Grietherorter Oxbow (Lower Rhine River, Germany), spanning the nineteenth and twentieth centuries. Therefore, a 370 cm-long sediment core was retrieved and analyzed using a non-target GC–MS screening. The identified contaminants were quantified and grouped into five contaminant groups: (I) aromatic compounds (e.g., polycyclic aromatic hydrocarbons (PAHs)); (II) halogenated compounds (e.g., polychlorinated biphenyls (PCBs), organochlorine pesticides, flame retardants (PBDEs)); (III) non-halogenated technical compounds (e.g., diisopropylnaphthalenes (DIPNs), diphenylamines); (IV) personal care products and pharmaceuticals (e.g., linear alkyl benzenes (LABs), methyltriclosane) and (V) further functionalized compounds (e.g., carbazoles, dibenzothiophene). Concentration maxima for most POPs reflect industrial emissions from the Rhine-Ruhr region during the mid-20th-century peak industrialization. Legacy contaminants (PCBs, dichlorodiphenyltrichloroethane (DDT) metabolites, coal-tar derivatives) demonstrate the long-term preservation potential of lipophilic pollutants in oxbow sediments. With the distribution pattern chronostratigraphic markers are identified, correlating with known industrial activities (e.g., coal processing, chemical manufacturing, and agriculture), followed by restrictions for pollutants like PCBs and their substitutes Ugilec 141®. This study demonstrates that recently abandoned, partly connected oxbows serve as valuable environmental archives for reconstructing anthropogenic pollution histories in heavily impacted fluvial systems.