Grouping strategies for assessing and managing persistent and mobile substances#

Authors#

Parviel Chirsir, Emma Helena Palm, Sivani Baskaran, Emma Schymanski, Zhanyun Wang, Raoul Wolf, Sarah E. Hale, Hans Peter H. Arp

Abstract#

Background:#

Persistent, Mobile and Toxic (PMT), or very Persistent and very Mobile (vPvM) substances are a wide class of chemicals that are recalcitrant to degradation, easily transported, and potentially harmful to humans and the environment. Due to their persistence and mobility, these substances are often widespread in the environment once emitted, particularly in water resources, causing increased challenges to water treatment processes. Some PMT/vPvM substances such as GenX and perfluorobutane sulfonic acid have been identified as substances of very high concern (SVHCs) under the European REACH regulation. With hundreds to thousands of potential PMT/vPvM substances yet to be assessed and managed, effective and efficient approaches that avoid a case-by-case assessment and prevent regrettable substitution are necessary to achieve the European Union’s zero-pollution goal of a non-toxic environment by 2050.

Main:#

Substance grouping has helped global regulation of some highly hazardous chemicals, e.g., through the Montreal Protocol and the Stockholm Convention. This article explores the potential of grouping strategies for assessing and managing PMT/vPvM substances. It provides an overview of PMT substances, reviews the definition of PMT/vPvM criteria and various lists of PMT substances available. It covers the current definition of groups, compares the use of substance grouping for hazard assessment and regulation, and discusses the advantages and disadvantages of grouping substances for regulation. The article explores strategies for grouping PMT/vPvM substances including read across, structural similarity and commonly retained moieties, as well as the potential application of these strategies using cheminformatics to predict P, M and T properties for selected examples.

Conclusion:#

Effective substance grouping can accelerate the assessment and management of PMT/vPvM substances, especially for substances that lack information. Advances to read-across methods and cheminformatics tools are needed to support efficient and effective chemical management, preventing broad entry of hazardous chemicals into the global market and favouring safer and more sustainable alternatives.