Persistent, mobile and toxic substances in the environment: A spotlight on current research and regulatory activities

Certain persistent and polar substances may pose a hazard to drinking water resources. To foster the knowledge exchange in this field the Working Group Environmental Monitoring of the German Chemical Society (GDCh) Division Environmental Chemistry and Ecotoxicology discussed at their meeting in December 2018 the significance and relevance of persistent, mobile and toxic chemicals (PMT substances) in the environment. Five oral contributions highlighted not only various aspects such as the identification of potential PMT substances based on certain properties and their possible regulation under the European REACH regulation, but also current developments in the analysis of PMT substances and results from environmental monitoring. The data presented prove that many persistent and mobile substances can be detected in surface waters. Once detected, it can be complex and costly to identify sources and reduce inputs, as a case study on 1,4-dioxane in Bavarian surface waters shows. The same applies to the removal of polar substances from raw water for drinking water production. Today, scientific advances in analytical methods make it easier to identify and quantify even very polar substances in water samples. In addition to the targeted analysis of critical chemicals, non-target screening is playing an increasingly important role. This opens up the possibility of detecting substances in water samples that have not previously been investigated in routine monitoring and testing their relevance for humans and the environment. However, the list of potentially occurring PM substances that have not yet been investigated is still very long. Further methodological improvements seem necessary here. In view of the evidence for the presence of PMT substances in the environment (e.g., trifluoroacetic acid and 1,4-dioxane) and the potential risks for drinking water abstraction, it seems important under consideration of the precautionary principle to identify and prioritise relevant REACH-registered substances. The assessment should be based on the intrinsic properties and the emission potential of the compounds. The implementation of a detailed proposal made at European level to regulate PMT and very persistent and very mobile (vPvM) substances in the context of REACH would ensure that chemicals identified as being substances of very high concern according to the PMT and vPvM criteria are subject to authorisation in future.