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The PMT screening tool is an online tool designed to predict the persistence (P), mobility (M) and human toxicity (T) of chemicals based on modelling results for the endpoints of interest. Emissions of chemicals that are persistent and mobile in the aquatic environment and hazardous to humans and/or ecosystems (PMT), or that are very persistent and very mobile (vPvM) should be avoided. For this purpose, screening approaches are needed to identify PMT/vPvM chemicals as early as possible. The PMT screening tool can be used by permit officers (responsible for e.g. industrial wastewater discharge permits), risk assessors, drinking water suppliers, industry and others to screen chemicals for potential PMT concerns.
The basic approach is to score chemicals from 0 (no or very low PMT potential) to 1 (very high PMT potential). Also, for the individual properties P, M, and T as well as for the overall PMT-score, the scores are constructed to give:
- a score of 0 to 0.33 to indicate low to moderate P, M and/or T potential;
- a score of 0.33 to 0.5 indicates high P, M and/or T potential;
- and a score of 0.5 to 1 indicates very high P (vP), M (vM) and/or T potential.
For a substance to have a concern for PMT properties, all three indicators (or property criteria) must be met for the same chemical (P and M and T). ). However, to identify as many potential PMT candidates as possible, we decided to give a chemical a high overall PMT-score ( ≥ 0.33) even if that chemical scores low to moderate on P, M or T. This enables the identification of chemicals of concern that may not score high on all three indicators (P, M and T) but that do cause a concern based on the combination of (some of) these indicators. From a screening point of view, this more cautious approach is considered valuable.
The scientific paper describing the methodology in detail is available via this link. The methodology is based on earlier work by Hartmann et al. (2021) and Rorije et al. (2011). A more practical description of the methodology as well as its application domain and interpretation of its output can be found on the PMT/vPvM information page.
A CAS-number of a chemical structure needs to be provided as input. The user can either search a single substance using the tab ‘Search one substance’ or a list of substances (CAS-numbers) using the tab ‘Search a batch of substances’.
The output for a single substance search includes the CAS-number and (when available) the name of the input chemical as well as the overall combined PMT score and the individual P, M and T scores for that substance. Furthermore, an explanation of the scores is provided, which includes the predicted indicators for P and M that are used for the calculation of the scores. A link to more detailed substance information is also given, if available.
The output for the batch search includes the same information as the single substance search, except for the explanation on the P and M scores. A link to get that information per substance is included.
It should be noted that a low or high PMT score is only a first indication that the substance is of potential low or high concern (for having PMT properties). The screening approach should be used as a first screening step, which needs to be followed by further investigation of the properties leading to high predicted PMT-scores. Follow-up can for instance include collection of emission data and/or experimental data on persistence, mobility and/or toxicity. When evaluating the presented output, it is advised to not only look at the smiley indicators but to pay attention to the underlying scores.
Finally, it should be noted that predictions of low PMT concern (or absence of any prediction) does not mean that a chemical can be used safely. Other effects or properties might not be excluded. Furthermore, substances with high P and/or T scores, but low M scores, might still be of potential concern for human health and/or the environment for instance because of potential persistent, bioaccumulative and toxic (PBT) properties or Carcinogenic, Mutagenic and/or Reprotoxic (CMR) properties. For more information please read the PMT/vPvM information page, PBT/vPvB information page, CMR information page or ZZS information page (in Dutch).
- Carcinogenic, mutagenic or reprotoxic
- Persistent, bioaccumulative and toxic
- Persistent, mobile and toxic
- Very persistent and very bioaccumulative
- Very persistent and very mobile
- Dutch Substances of Very High Concern (in Dutch: Zeer Zorgwekkende Stoffen)