Trace substance load in the Danube – origin and ongoing monitoring of new unknowns

Abstract

Raw and drinking water monitoring is crucial for a safe drinking water supply. In addition to targeted analysis, untargeted screening approaches are gaining importance since these methods enable the detection of unknown or not expected trace substances. Both methods were established to examine the Danube and its tributaries around the metropolitan area of Ulm. The highest median concentrations were determined for highly polar substances. These compounds need particular attention, as they are often persistent and mobile and may thus break through natural or technical barriers and reach the drinking wa-ter. More than half of the positive findings in the Danube represented pharmaceuticals and X-ray contrast media. Unexpec-tedly high concentration peaks with large temporal variance suggest industrial point sources. A final source apportionment by intelligent sampling, analysis and data processing strategies is already planned and will establish the basis to take specific measures for environment and human health protection.