Robust techniques based on liquid (LC) and gas chromatography (GC) coupled with high-resolution mass spectrometry (HR-MS) enable sensitive screening, identification, and (semi)quantification of thousands of substances in a single sample. Recent progress in computational sciences has enabled archiving and processing of HR-MS ‘big data’ at the routine level. As a result, community-based databases containing thousands of environmental pollutants are rapidly growing and large databases of substances with unique identifiers allowing for inter-comparison at the global scale have become available. A data-archiving infrastructure is proposed, allowing for retrospective screening of HR-MS data, which will help define the ‘chemical universe’ of organic substances and enable prioritisation of toxicants causing adverse environmental effects at the local, river basin, and national and European scale in support of the European water and chemicals management policy.