Consisting of two phenyl rings, which can be chlorinated at up to ten positions, they form a group of 209 congeners typically occurring in mixtures. Due to their chemical stability, temperature resistance and dielectric properties they had been widely used, for example, in closed electrical equipment but also openly as plasticizers in polymers and paints. It was estimated that between 1 and 1.5 million tons of PCBs were produced worldwide since the 1920s until being mostly banned in the 1980s and 90s. Because of improper discharge and high environmental mobility, they are not only found around urban industrialized places like Munich in Germany, the San Francisco Bay in the United States or megalopolises in China, but also in more rural areas like the Himalayan riverine network in Pakistan or down at the Mariana trench in the Pacific Ocean. The omnipresence is particularly concerning as it is known that PCBs negatively influence early childhood development and are declared carcinogenic among other harmful effects. In the river Nile in Egypt concentrations of PCBs between 14 and 20 µg L -1 were measured , while the United States Environmental Protection Agency enforces a maximum contaminant level of 0.5 µg L -1 with the declared goal of zero residues in their national primary drinking water regulations. In fact, the Stockholm Convention set the sophisticated aim of complete and environmentally-friendly elimination of PCBs until 2028 to obey the sustainable development goals (SDGs) of the United Nations. Therefore, it is necessary to efficiently clean waste water from PCBs at very low concentrations, so-called trace concentrations. In Germany more than 96 % of waste water is treated by conventional waste water treatment plants (WWTPs), which typically consist of a mechanical, a biological and a precipitation stage. However, even state-of-the-art WWTPs having an additional fourth stage comprised of oxidation via ozonation and/or activated carbon filters cannot remove all trace contaminants sufficiently. Consequently, advanced water cleaning is an active field of research. One way to classify approaches is by their biological, chemical and physical (or combined) nature. Microbial remediation of PCBs, i.e., degradation by microorganisms like A. xylosoxidans, is a low energy-consuming and environmentally-friendly approach. However, it takes long time and works less effective for stable chlorination at ortho-positions on the phenyl rings. Therefore, oxidation processes like the aforementioned ozonation or treatment with Fenton's reagent (Fe 2+ /H2O2) as well as dechlorination by reduction as shown with zero-valent iron provide more versatile degradation strength. Here, cost and environmental impact of the treatment itself are the issues of concern. Next to membrane filtration, which is inherently limited for large water volumes, POPs-attractive adsorbents providing large surface areas resemble a simple and cost-effective concept. As mentioned before, activated carbon is one of the most studied and already employed adsorbents for water remediation today providing high surface area but typedependent PCB adsorption efficiencies. Therefore, costly modification processes are necessary to target specific pollutants. Another elegant approach is to use superparamagnetic iron oxide nanoparticles (SPIONs), known for their theranostic medical applications or as precursors for Fischer-Tropsch catalysts, as adsorbents to enable removal from the water phase by applying a magnetic field gradient. Examples show SPIONs coated with complex molecules like β-cyclodextrins or tediously synthesized polymeric shells to make them attractive for PCBs.