Tracking the distribution of persistent and mobile wastewater-derived substances in the southern and central North Sea using anthropogenic gadolinium from MRI contrast agents as a far-field tracer
Dennis Kraemer, Katja Schmidt, Franziska Klimpel, Uwe Rauch, David Ernst, Sophie Anna Luise Paul, Matthias Haeckel, Andrea Koschinsky, Michael Bau
Abstract
The use of the rare earth element gadolinium (Gd) in contrast agents for magnetic resonance imaging has led to a significant (micro-)contamination of riverine and coastal environments in many parts of the world. This study comprises a detailed investigation on the rare earth elements and yttrium inventory of the North Sea and also reports data for the major tributaries Thames, Rhine, Ems, Weser and Elbe. We show that large parts of the southern North Sea, including the Wadden Sea UNESCO Natural World Heritage site, are (micro)contaminated with Gd from Gd-based contrast agents (GBCA). Their dispersion reveals their estuarine input and allows to effectively track water masses and currents. The chemical persistence and conservative behavior of GBCA, coupled with the low detection limits of state-of-the-art analytical methods, makes the anthropogenic Gd a sensitive screening proxy for monitoring similarly stable, but potentially hazardous, persistent chemical/pharmaceutical substances in natural waters. • Rare earth element distributions in the North Sea and Elbe, Ems and Weser rivers • Significant contamination with anthropogenic Gd from MRI contrast agents • Anthropogenic Gd introduced into rivers and North Sea via wastewater discharge • Anthropogenic Gd is a screening proxy for monitoring wastewater-derived substances. • Wastewater-derived substances in UNESCO World Natural Heritage Site Wadden Sea