Persistent and mobile – KWR joins ZeroPM’s workshop in Dessau, Germany

ZeroPM’s Mission and Workshop Objectives

On the 19^th and 20^th of September 2024, KWR travelled to Dessau-Roßlau, Germany, to participate in the 2^nd workshop of the ZeroPM consortium, hosted by the German Federal Environment Agency (UBA). This EU project is one of the most active initiatives aimed at establishing an evidence-based multilevel framework to minimize the use, emissions, and pollution from persistent and mobile substances, thereby protecting European water resources and mitigating risks to human health.

This workshop, titled “Achieving Zero Pollution of Persistent and Mobile Substances: Prioritization through Substance Grouping and Risk Assessment,” gathered around 140 participants from academia, government, industry, NGOs, regulatory bodies, and the water sector. The Chemical Water Quality and Health team accepted the open call from the consortium, recognizing the relevance of the drinking water sector’s presence. The content and organization of the event were of high quality, providing an opportunity to expand and strengthen relationships among experts and other stakeholders in fields where KWR is actively involved. The discussions in the lively Discussion Cafés allowed participants to learn, share insights, raise doubts and explore ways to move towards a future with zero water pollution.

A significant focus was placed on “forever chemicals,” which are resistant to degradation in the environment (persistent, P) and easily move between matrices (mobile, M), particularly in water, and across large distances (Figure 1). PM substances are now ubiquitous in water, air, soil, and living organisms worldwide. They are very difficult to remove once in the environment and can contaminate our drinking water sources. Without effective actions on removal, prioritization and prevention, their presence and that of other concerning contaminants is expected to only increase.

Figure 1. EU CLP criteria for PMT/vPvM substances. Source: Chirsir et al. (2024)

The workshop addressed topics directly related to ongoing and upcoming research activities at KWR, including screening approaches for persistence and mobility, transformation products, substance grouping, exposure assessment, NAM-based hazard characterization, in vitro-in vivo extrapolation, risk assessment, reducing data gaps, quantifying uncertainties, and multi-stakeholder approaches towards zero pollution.

Research Needs and Limitations in Identifying Hazardous Substances

The event began with essential perspectives from regulatory bodies, including ECHA and UBA, discussing the research needs and limitations in identifying and prioritizing hazardous substances. Daunting figures were presented by some presenters, for example, highlighting the small number of substances currently regulated worldwide compared to the vast number of potentially very persistent and mobile (vPvM) substances and their transformation products.

The event also offered up-to-date knowledge on prioritizing PMT substances through grouping strategies and risk matrices. Grouping strategies are increasingly seen as a pragmatic alternative for singly assessing the hazardousness of substances by shared features, i.e., assess substances in bulk using proxy criteria rather than empirically testing each individual substance.

For example, substances can be grouped based on structural similarity or retained moieties from transformation products. In the first approach, we can assume that structurally similar substances will likely share similar properties of concern. Consequently, a large group of substances may be regulated and managed similarly. An example is the recent proposal to restrict thousands of PFAS in the EU, despite limited information on many of them; the few for which we have hazard and risk information are confidently viewed as concerning.

Another approach to address knowledge gaps involved a large ontological study analysing the co-occurrence of keywords (such as PFAS and toxicity) in scientific publications to signal potential toxicological and hazardous associations.

Toxicity and Risk-Based Approaches for Persistent, Mobile, and Toxic Substances

In the second day of the conference, the focus shifted to the toxicity of classes of substances that are not only recalcitrant to degradation and easily transported, but also potentially harmful to humans and the environment (persistent, mobile and toxic; PMT) (Figure 1). The latest developments in conceptualizing a prioritization scheme based on the risk of substances were shared with attendees, and applications of multimedia activity models for evaluating the fate of persistent and mobile substances were also presented.

Additionally, the integration of new toxicological results (e.g., endocrine-disrupting properties) of water-relevant substances using New Approach Methodologies (e.g., in vitro assays, PBK modelling) was discussed. A lively discussion followed, where stakeholders explored how to advance these approaches towards risk-based prioritization and regulatory application. Many drinking water companies struggle with substances like TFA, 1,4-dioxane, sulfamic acid, EDTA, melamine, 1H-benzotriazole, chlorothalonil M4, dikegulac and DMS. However, little is known about their emission or that of parent compounds.

Interestingly, several attendees emphasized the critical need of publicly accessible information about waste emissions, without which even the best computer models cannot provide accurate predictions. Nonetheless, it was encouraging to witness that, despite the complex challenges of bridging science and practice, scientists and regulators across various domains (chemical, environmental, health) are increasingly willing to collaborate in finding solutions among all the data-gaps and uncertainties. ‘Bridging science to practice’ is KWR’s motto, and we take pride in this role by, among its many activities, expanding the dialogue at events such as ZeroPM’s workshop.

In summary, in addition to the conceptual and practical knowledge shared among experts, this gathering provided an opportunity to stay up-to-date about the latest efforts for a future without pollution alongside key stakeholders, including academia, regulatory authorities, and industry.

The Chemical Water Quality and Health team congratulates our colleagues at the ZeroPM for a successful gathering and looks forward to its continued success!