A regulatory perspective on the systematic use of high-resolution mass spectrometry non-target screening data in environmental monitoring and chemicals management – use cases from the German NTSPortal

Background Society aims for a pollutant-free environment, reflected in initiatives under the European Green Deal, which seek to reduce hazardous substances and promote safe, sustainable chemical use. Comprehensive exposure data are needed to identify sources, understand mixtures and eliminate sources of chemical pollution. High-resolution mass spectrometry non-target screening (HRMS NTS) is increasingly used in environmental regulatory context to chemically characterize the environment as completely as possible and retrospectively screen for known and emerging substances. The data used in this study come from the German NTSPortal, a permanent application for archiving and visualising riverine HRMS NTS data from national and state laboratories. Results The NTSPortal uses an internal spectral library that provides identification levels comparable to standardised target analysis, facilitating the regulatory acceptance of HRMS NTS data for prioritisation and mixture assessment. We provide several use cases demonstrating the wide applicability of this approach in different sectors of chemicals management. The analysis showed that despite marked spatial variability between sampling stations, mixture composition remained stable over time, with 855 of 1721 substances detected at least once and 247 substances occurring ubiquitously. HRMS NTS data demonstrated the effectiveness of regulatory measures, such as use restrictions and complete bans, e.g. declining trends for carbendazim and climbazole. Furthermore, the findings highlight their potential to evaluate the effectiveness of the revised Urban Waste Water Treatment Directive and to support One Health concepts. Conclusions Data from the German NTSPortal enabled a comprehensive, matrix-spanning and temporal characterisation of riverine chemical mixtures, revealing both stable mixture compositions over time and persistent, catchment-specific substances. These data facilitated high-resolution mixture assessments across space and time, alongside trend analyses that meet regulatory needs in environmental monitoring and chemical risk assessment. Further temporal, spatial, chemical and matrix-spanning expansion of HRMS NTS repositories will enhance their value for environmental monitoring programmes. Strengthening interoperability, implementing FAIR data principles, and developing advanced tools for prioritisation, quantification and toxicity prediction, including AI-based approaches, will be crucial to fully realise the regulatory potential of NTS portals in the future.