Persistent, Mobile and Toxic Chemicals

As this category does not yet exist as a specific REACH SVHC category, these substances are currently classified under the category Equivalent Level of Concern (ELoC).

In 2019, 29 persistent, mobile and toxic (PMT) and very persistent and very mobile (vPvM) chemicals were added to the SIN List. The assessments were performed by Professor Martin Scheringer and Dr Helena Andrade from ETH Zürich. At the time, there were no EU-wide criteria for PMT, and the criteria for mobility were the same as those proposed by the German Environment Agency (UBA).

In 2025, an additional 18 PMT/vPvM chemicals were added to the SIN List. This time using the new EU Classification, Labelling and Packaging (CLP) Regulation PMT/vPvM criteria, available since the PMT/vPvM were added as a new hazard classes in 2023 (note that these criteria differ from the UBA criteria, most importantly, the mobility thresholds are lower). The assessments were performed by a team of experts led by Professor Hans Peter Arp from the Norwegian Geotechnical Institute (NGI) and Dr Sarah Hale from Technologiezentrum Wasser/German Water Centre (DVGW-TZW), as part of the EU Horizon 2020 research and innovation project ZeroPM; Zero pollution of persistent, mobile substances.

The assessment processes in 2019 and 2025 both relied on structured weight-of-evidence (WoE) approaches since high-quality, experimental biodegradation simulation studies are rarely available. In 2019, chemical property estimations were used for an initial assessment and to prioritise chemicals for more in-depth data collection via the open literature. In 2025, the main guiding document for the PMT assessment was the CLP guidance, and the starting point was to apply the guideline principles to assess the chemicals based on openly available data in the REACH registration dossiers, in some cases complemented with data from the literature.

In both 2019 and 2025, the assessment process started with lists of several hundred chemicals that are potential PMT/vPvM (compiled by UBA and the NGI). From these extensive lists, prioritisations were made to select a limited number of chemicals for assessment, with the goal of including them on the SIN List. For each chemical, a fact sheet was written, describing the assessment and the underlying data, together with additional information about the chemical. Key data from these fact sheets is made available on the SIN List entries.

The assessment processes from 2019 and 2025 are described in more detail below.

 

The assessment process in 2025

The assessment process started with a list comprising 343 vPvM/PMT substances. The database included data on substance properties related to persistence, mobility, and toxicity, as well as uses from REACH registration dossiers, quantitative and qualitative structure-activity relationships (QSAR) derived data on substance properties, estimates of emission likelihood, monitoring data, and information on regulatory status. To this database, potential PMT/vPvM chemicals in focus in the ZeroPM project were added. For all chemicals possible, the database was complemented with modelled probabilities of the substance meeting P and M criteria.

To select the chemicals to include as PMT/vPvM on the SIN List, the following steps were taken:

  • Initial screening for substances with a high probability of meeting the CLP PMT/vPvM criteria (based on the modelling results), which are in industrial use and not already on the SIN List.
  • Further prioritisation based on urgency of action (based on scores for emission potential, environmental occurrence, regulatory status and inclusion in focus lists in the ZeroPM project) and the likelihood of meeting persistence (P) and mobility (M) criteria (using again the modelling results, with a higher likelihood threshold) rendered a shortlist of more than 60 chemicals for further assessment.
  • Further substantiation of the vPvM/PMT assessment was conducted for the shortlisted chemicals, starting with those with the highest scores. Chemicals with enough evidence of PMT/vPvM properties were selected to be included on the SIN List. Chemicals lacking enough evidence of PMT/vPvM properties were identified as relevant for more testing.

In general, assessing the persistence of the chemicals was the most difficult task, as data were scarce and the initial results seemed scattered and inconsistent, pointing in different directions.

Reliable and high-quality data on persistence from a simulation test on biodegradation, i.e. half-lives directly comparable to the persistence criteria, were seldom available. Therefore, a tiered WoE approach to assess persistence based on screening tests for ready and inherent biodegradation was defined in collaboration with experts within the ZeroPM project. Chemicals that did not degrade at all, or only to a small extent, in screening tests of biodegradability, were identified as potentially being persistent. The available results were carefully scrutinised to determine if the test was protocol-compliant and relevant to the assessment. If additional data supported it, we concluded that the chemical has properties meeting the P criteria.

The assessment of mobility and toxicity was more straightforward. For mobility, experimental test results for the organic carbon-water partition coefficient (KOC), as described in the REACH registration dossiers, or, when suitable, estimations of this partitioning coefficient, were compared to the M criteria. For toxicity assessments, the classifications in the CLP regulation served as the starting point. For chemicals indicated to be toxic but not classified, the expert team collected data from open databases and literature to assess toxicity in relation to the T criteria.

 

The assessment process in 2019

The assessment process began with a list of 344 chemicals in total. This list was reduced after screening using EPI Suite Estimations and by removing non-REACH relevant chemicals or chemicals already on the SIN List. Some chemicals were also manually added because they were specifically interesting, and the total number of evaluated chemicals was 24.

After this selection was finished, several aspects were considered in the evaluation of the 24 chemicals:

  • Existing regulation or classification under REACH and CLP or as Persistent Organic Pollutant (POP) under the Stockholm Convention (regarding the P and T dimensions).
  • Results from the screening study by (Arp and Hale, 2019): chemicals that have PMT properties according to the data generated were given high priority. From the 24 chemicals we selected, this study classified one as PM, six as PMT, nine as vPvM, and eight as vPvMT.
  • In parallel, a technical note by this same group, Arp et al., has been adopted by the NORMAN network as the NORMAN Potential PMT substances list (Arp, 2018). From our final selection of 24 chemicals, 16 were present in this list.
  • Production volume: Among the chemicals with PMT properties, higher priority was given to high-production-volume chemicals (HPVCs) or those registered under REACH in larger tonnage bands.
  • The criteria for mobility were the same as those proposed by the German Environment Agency (UBA) in its 2019 criteria version, which was also presented at the CARACAL meeting.

For each chemical, an extensive search was conducted in publicly accessible databases as well. Basic information on the chemical, its applications, and expected PMT behaviour was collected and summarised, along with additional information wherever relevant, such as the detection of the chemical in the environment.

Chemicals were, after discussions with experts from member states, included in the SIN List if they fulfilled at least one of the following:

  • Fulfilled the REACH Annexe XIII “P” and/or “T” criteria in combination with Mobility criteria as proposed by the German UBA;
  • Showed substantial structural similarity to chemicals that are already regulated as P/vP and/or T under REACH or the Stockholm Convention on POPs;
  • Degraded in the environment or organisms into substances that fulfil 1.