Substances of possible concern

1. This web page is intended to inform visitors to the OSPAR website about the OSPAR List of Substances of Possible Concern, and its role in OSPAR’s efforts to tackle hazardous substances in the aquatic environment. The "question and answer" format is intended to give readers a quick overview of the list, the criteria used to develop it, and its robustness and status. A contact procedure is given for readers who could provide data and information to improve the list.

2. The OSPAR List of Substances of Possible Concern is a dynamic working list is revised as new information becomes available. This may lead to exclusion of substances present on the current version of the OSPAR List of Substances of Possible Concern and to inclusion of other substances, if data on persistence, toxicity and liability to bioaccumulate (or evidence that they give rise to an equivalent level of concern) show that they should be added. This version of the OSPAR List of Substances of Possible Concern was last revised in 2015. OSPAR 2023 agreed to include the OSPAR List of Substances of Possible Concern as an annex to the OSPAR List of Chemicals for Priority Action

3. The OSPAR Commission is publishing this List of Substances of Possible Concern in order to enable the transparency of its decisions on which substances to classify as chemicals for priority action, and to provide an opportunity for any errors or omissions in the data on which those decisions were based to be put right. Our goal is to keep this information up-to-date and accurate. If errors or omissions are brought to our attention, they will be corrected.

4. Section A includes individual substances belonging to or related to prioritised substances or groups, such as brominated flame retardants, PAHs, PCBs, nonylphenols and perfluorinated substances. While the group of substances has been prioritised by OSPAR, not all individual substances have been evaluated for their intrinsic properties and risk for the marine environment in the Background Documents. They are therefore reflected on the List of Substances of Possible Concern.

5.OSPAR’s main objective for hazardous substances is to prevent pollution by hazardous substances, by eliminating their emissions, discharges and losses, to achieve levels that do not give rise to adverse effects on human health or the marine environment with the ultimate aim of achieving and maintaining concentrations in the marine environment at near background values for naturally occurring hazardous substances and close to zero for human made hazardous substances (OSPAR Strategy for the protection of the marine environment of the North-East Atlantic (Agreement 2021‑01).

6. In order to tackle the hazardous substances which are of possible concern to the marine environment, and to prioritise the substances of highest concern for immediate action, OSPAR developed a selection and prioritisation mechanism. This is described in the publication on the Dynamic Selection and Prioritisation Mechanism for Hazardous Substances (DYNAMEC) as published on the OSPAR web site. DYNAMEC is currently on hold whilst the List is under review.

7. The selection and prioritisation mechanism consisted initially of 3 basic steps:

step 1: an initial selection step which by a worst-case screening procedure identifies certain hazardous substances on the basis of their intrinsic hazardous properties of persistence, liability to bioaccumulate and toxicity (P, B and T). Definitions of P, B and T. These have been placed on the "List of Substances of Possible Concern" because they could adversely affect marine ecosystems;

step 2: a step which ranks these substances of possible concern according to their actual occurrence and effects in the marine environment;

step 3: a step which selects those substances from the ranked list judged to require priority action by OSPAR. Current OSPAR List of Chemicals for Priority Action.

8. OSPAR 2004 agreed that the focus of the further processes on the selection of substances is:

1. to consider new information on substances already on the List of Substances of Possible Concern;
2. to consider information on new substances not addressed under relevant EC initiatives and decide whether they should be added to the List of Substances of Possible Concern;
3. to consider information on substances proposed for addition to the List of Substances of Possible Concern via the Safety net procedure.

OSPAR will not, for the time being, take any new initiatives for prioritisation and ranking of substances. Agreement for Further Work in relation to the DYNAMEC Mechanism (Reference number: 2005-10). The List is under review.

9. OSPAR 2004 agreed to review the selection and prioritisation work taking place under the EC initiatives to identify any remaining significant gaps regarding the protection of the marine environment. OSPAR should then conclude whether to take up any such issues with the EC, or to fill any gap by further OSPAR work. To assist this review, OSPAR 2006 agreed further work on the substances of possible concern ( Agreement 2006-9) to narrow down the number of substances for efficient review by OSPAR. This consisted of a simple screening process in 2006 - 2009 of existing reliable evidence from easily accessible sources to identify substances for:

Section A - which warrant further work by OSPAR because they do not meet the criteria for Sections B - D and substances for which, for the time being, information is insufficient to group them in Sections B - D

Section B - which are of concern for OSPAR, but which are adequately addressed by EC initiatives or other international forums

Section C - which are not produced and/or used in the OSPAR catchment or are used in sufficiently contained systems making a threat to the marine environment unlikely

Section D - which appear not to be "hazardous substances" in the meaning of the Hazardous Substances Strategy but where the evidence is not conclusive

All substances listed in Sections A - D remain of possible concern and OSPAR can decide any time to take actions if considered necessary, especially if new information becomes available. The screening process and the information sources are summarised in the Screening Documentation. Extracts of the screening database can be obtained upon request from the Secretariat. OSPAR is continuing joint efforts to collect targeted information on substances in Section A to further clarify the concern of the substances and to direct any further actions which could be followed-up within OSPAR or brought to the attention of the most suitable international frameworks.

10. A number of substances which do not meet the full P, B and T criteria have already been added to the List of Substances of Possible Concern because it has been recognised that they give rise to a similar level of concern (for example, endocrine disruptors, or shown to be widely spread in the marine environment by monitoring). The procedures with which OSPAR may add further substances to the list on the basis of equivalent concern are presented in the Guidance on How to Apply the Safety Net Procedure for the Inclusion of Substances in the List of Substances of Possible Concern (Reference number: 2002-10).

11. The List of Substances of Possible Concern consists of the substances which have been selected on the basis of their intrinsic hazardous properties (step 1). The substances on the List of Chemicals for Priority Action are those which the OSPAR Commission has to date determined require priority action, based primarily on recommendations from DYNAMEC’s ranking process and expert judgement as to which substances represent the highest concern due to the amount produced, the degree of hazardous properties and/or the actual occurrence in the marine environment (steps 2 and 3). As the work of OSPAR progresses, it is envisaged that the List of Chemicals for Priority Action will be further updated with substances from the List of Possible Concern in order that the objectives of the Strategy can be progressively met. OSPAR 2023 agreed that the List of Substances of Possible Concern sould be included as an annex to the List of Chemicals for Priority Action.

12. The substances on the OSPAR List of Substances of Possible Concern have been identified by a worst-case screening of a number of databases with experimental data on P, B and T. However, when experimental data are not available, substances have been identified by employing different models (QSARs: Quantitative Structure Activity Relationships) which estimate these values on the basis of chemical structure. The screening is not exhaustive as not all possible data sources have been available or because of limitations in the models employed. Furthermore, some substances may falsely have been selected due to data errors or outliers.

13. The P, B and T criteria used for the selection of the Substances of Possible Concern are described in the Agreement on Cut-Off Values for the Selection Criteria of the OSPAR Dynamic Selection and Prioritisation Mechanism for Hazardous Substances (Reference number 2005-09).

14. The underlying data used for the selection of the Substances of Possible Concern can be found on the relevant fact sheets.

15. Expert judgement has been undertaken for only a part of the substances. Data for most of the substances have only been subjected to a preliminary scrutiny to ensure that they are sufficiently credible to indicate a possible concern. Therefore, there is still considerable room for improvement and confirmation of the data, that were used in a worst-case screening procedure, especially if appropriate experimental values are available which may replace QSAR estimates. The extent to which the data for a certain substance has been scrutinised is indicated in the box "remarks" of the fact sheet for that substance.

16. OSPAR is keen to update the list and the fact sheets with more good quality data, and has been working with industry trade associations and OSPAR Contracting Parties to obtain such information. The more the list and the fact sheets become updated and validated with good quality data, the better the list will act as a tool to flag up those substances which are likely to be of concern to the marine environment. The List is under review.

17. OSPAR is keen to get more good quality data with regard to the intrinsic properties (P,B and T) of these substances, or other substances with similar properties. However, OSPAR also does need information with regard to the production and use of these substances, and information on their occurrence in the environment.

18. Following expert review of additional data that has come forward, OSPAR has removed several substances from the list since it was first published. Information on these substances and the reasons for their removal can be found on the List of Substances Removed from the OSPAR List of Substances of Possible Concern (Reference number 2004-13).

19. The fact sheets for the deselected substances have been updated to include information about the reasons for deselection. Following this the fact sheets have been removed from the website and will not be updated any further. They are stored in the database of the OSPAR Secretariat and can be made available upon request to the Secretariat.

20. Visitors to this website who have information which would enable OSPAR to update its List of Substances of Possible Concern are invited to contact the OSPAR Secretariat who will advise them further regarding the submission of relevant information. An empty fact sheet for the submission of such information and a glossary explaining the content of the fact sheet are available for downloading.

21. The Commission accepts no responsibility or liability whatsoever with regard to the contents of the list or the supporting data sheets. Efforts have been made to ensure that the information given is as accurate as possible, but it is not necessarily comprehensive, complete, accurate or up-to-date.

22. This disclaimer is not intended to limit the liability of the Commission contrary to any obligations imposed by applicable national law nor to exclude liability for matters which may not be excluded under that law.