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     ANNEX 7

    (Ref. ?7.8)





    Cut-Off Values for the Selection Criteria of the OSPAR Dynamic Selection and

    Prioritisation Mechanism for Hazardous Substances

     1(Reference Number: 2005-9)

1. The intrinsic properties of individual substances, specifically whether they are persistent (P), toxic (T)

    or liable to bioaccumulate (B), determine whether they fall within the definition of hazardous substances

    given in the OSPAR Strategy with regard to Hazardous Substances. These three intrinsic properties (PTB

    criteria) have been used, along with cut-off values for each, as the criteria for selecting substances in the

    Initial Selection Procedure of the Dynamic Selection and Prioritisation Mechanism. The criteria are also used

    for selection of new substances (c.f. Agreement for Further Work in relation to the DYNAMEC Mechanism,

    reference number: 2005-8), as well as for deselecting substances. The cut-off values for each of these criteria

    are as follows:

     2Persistency (P): ....................................... Half-life (T) of 50 days and ?

    Liability to Bioaccumulate (B): ............... log K>=4 or BCF>=500 and ow

    Toxicity (T) ............................................ T: acute L(E)C=<1 mg/l, long-term NOEC=<0,1 mg/l aq50


     T: CMR or chronic toxicity mammalian

2. This selection is a combination of the least stringent criteria considered during the development of the

    Initial Selection Procedure. For aquatic toxicity, contrary to the EC classification, mammalian toxicity is

    added in addition to the criteria for the aquatic environment (counts for all selections). For bioaccumulation 3the selected cut-off value is the same as that proposed for international harmonisation in classification and

    labelling. For persistence, the principal criterion is that the substance has a half-life in the freshwater or

    marine environment of 50 days or more. Further specification of the persistence criterion, including

    approaches applied in the absence of data on the half-life of a substance, are given in Appendix 1.

1 This will replace agreement number 2001-1. Furthermore a new edition of the ”DYNAMEC Manual”, The Dynamic

    Selection and Prioritisation Mechanism for Hazardous Substances (DYNAMEC), OSPAR publication 2002/146,

    will be prepared to take account of this revision of its Annex 3.

    2 In the absence of data on half-lives, alternative approaches have been agreed, as described in Appendix 1, which

    allow the use of different types of available information on the biodegradability of a substance.

    3 The process for and the results of the OECD Global Harmonisation of Classification Criteria can be found on the

    Internet at


    OSPAR Commission Summary Record OSPAR 2005 OSPAR 05/21/1-E, Annex 7

    Appendix 1

Persistency Criteria within the Hazardous Substances Strategy

    1. The persistence of a substance reflects the potential for the substance to reach the marine environment and to be transported to remote areas as well as the potential for long-term exposure of organisms. In order to assess the persistence in the marine environment in the context of the OSPAR Hazardous Substances Strategy an approach is applied that allows the use of different types of available information on the biodegradability of a substance. In this approach three different levels of information are defined: ? Level 3: Experimental data on persistence

    ? Level 2: Other experimental data

    ? Level 1: Data from biodegradation estimation models

    2. An explanation of the type of information that is relevant within these levels and the relevant cut-off values is given below. It must be noted that this approach reflects existing knowledge on biodegradation and should be considered as a pragmatic approach that makes optimal use of the available data and methods. Clearly, more research is needed to better estimate persistence in the marine environment from existing biodegradation tests. Moreover, other degradation mechanisms such as hydrolysis and photolysis should be taken into account if they are relevant.

Level 3: Experimental data on persistence

    3. The half-life should be used as the first and main criterion for determining whether substances should be regarded as persistent in the context of the Hazardous Substances Strategy. Hence appropriate half-life data override data from levels 1 and 2. In principle persistence should be determined in relevant simulation test systems that determine the half-life under relevant environmental conditions. The most relevant conditions should be considered; e.g. for a substance that could reach the marine environment only through transport by freshwater, the half-life in the freshwater environment is the most relevant, provided that the residence time in freshwater is sufficiently long. A cut-off value of 50 days should be used in freshwater (as a transport medium) as well as in the marine environment when it is likely that the substance can reach this compartment. As a general rule, in dealing with cases for deselection in which half-lives in freshwater or marine waters are considered, the degradation tests performed according to OECD protocols (or equivalent) under the most relevant environmental conditions are preferred for assessing against the 50 day cut-off value. Extrapolation of DT values to other conditions (e.g. temperature) will not be relied upon without 50

    justification, and tests performed under particular conditions need to be evaluated on a case by case basis.

    4. The assessment of the half-life should include consideration of PBT-properties of metabolites. A substance is not considered to be a PBT substance if both of the following conditions are met: (i) the half-life of the parent compound is less than 50 days and (ii) the resulting metabolites are not PBT chemicals.

    5. Half-life determination from experimental studies using a water-sediment system may be hampered by the formation of unextractable residues in the sediment, also called bound residues, that hardly exhibit further degradation (very slow formation of CO). Usually the nature of the bound residues cannot be 2

    clarified. If the bound residues would cause toxic effects, and correspond to a significant amount of the original parent substance, the parent substance (if it fulfills the B and T criterion) should be considered a PBT substance. A "significant amount" of bound residues could be any amount corresponding to more than 10% of the parent substance, but the assessment of what is a significant amount should be made on a case by case basis. Concerns over bound residues should be investigated through the use of sediment toxicity testing (using Chironomus or other appropriate sediment dwelling organisms) or by other types of tests that could

    show whether those residues are harmful to organisms. When such a test points out that the bound residues do not have toxic effects, the substance is considered to be non-PBT.


    OSPAR Commission Summary Record OSPAR 2005 OSPAR 05/21/1-E, Annex 7

Level 2: Other experimental data

6. The available information relating to biodegradability is dominated by test results on Ready

    Biodegradability (OECD Test Guideline 301 a-d- or equivalent) and to a lesser extent by data on the Inherent

    Biodegradability (OECD TG 302 a-c or equivalent). The conditions for degradation in the freshwater and

    marine environment are very far from the conditions applied in these standard tests. Hence, extrapolation of

    the existing biodegradation information (either measured data from ready and inherent tests or results from

    QSAR modelling) to degradation rates in the marine environment is very difficult, and care should be taken

    not to over-interpret the outcome of the ready/inherent tests. However, in order to use the available

    information to select potentially persistent substances the results of different types of tests should be used in the following way:

    ? when results from inherent tests are available that indicate that the substance does not fulfil the criteria

    this is a clear indication that the substance can reach the marine environment and be persistent under

    marine conditions, and that its initial selection is warranted.

    ? when only test results from ready biodegradation test are available indicating that the substance does not

    fulfil the criteria the substance is also initially selected. However, it is recognised that there is an urgent

    need for (industry to provide) better realistic data in order to determine the real potential for persistency.

    It must be noted that in this case it is not proposed that inherent tests are performed but rather to go

    directly to Level 3 testing.

    ? data from inherent tests that fulfil the pass criteria for these tests may still be persistent under marine

    conditions. However, in order to make the best use of available information it can be accepted that the 4results of two specific tests are used when they fulfil certain criteria. These tests are:

    o Zahn-Wellens Test (OECD 302B): Pass level for ultimate degradation must be reached

    within 7 days, lag-phase should be no longer than 3 days, percentage removal in the test

    before degradation occurs should be below 15%, not tested with pre-adapted micro-


    o MITI II -test (OECD 302C): Pass level for ultimate degradation must be reached within

    14 days, lag-phase should be no longer than 3 days, not tested with pre-adapted micro-


7. A case by case assessment is needed in order to decide that a substance can be deselected for

    persistency using the results from the above mentioned inherent tests.

Level 1: Data from biodegradation estimation models

8. For many chemicals no experimental data are available at all, which makes the initial selection of these

    substances problematic. Fortunately, models are available such as the SYRACUSE BIOWIN model that can

    be used to estimate the potential for biodegradation in the environment. It is proposed that rather stringent

    cut-off levels are used in order to select those substances for which there is a fair level of concern regarding

    their potential for persistence in the marine environment. A combination of two BIOWIN models has been

    used for the application of QSARs in the initial selection mechanism. The first model (BIOWIN 1) indicates

    that a substance is not rapidly degradable in the environment. The second model (BIOWIN 3) indicates that

    ultimate biodegradation in the environment is expected to occur in weeks to months where the exact cut-off

    point is “calibrated” on the basis of the data base for 1,2,4-trichlorobenzene, a substance that is known for

    being rather persistent under environmental conditions. In model terms the cut-off values are BPP1<0,5 and

    BPP3<2,2. It is recognised that further work in the development of biodegradation QSARs is needed and that

    experience with the cut-off values would be beneficial for future application of QSAR models within further

    work in relation to the DYNAMEC mechanism.

     4 The criteria for the inherent tests are similar to the criteria defined in the EC Technical Guidance Document in

    support of Commission Directive 93/67/EEC on Risk Assessment for new notified substances, Commission

    Regulation (EC) No 1488/94 on Risk Assessment for existing substances and Directive 98/8/EC of the European

    Parliament and of the Council concerning the placing of biocidal products on the market, Chapter 3, Section 4,

    Environmental Risk Assessment Marine.


    OSPAR Commission Summary Record OSPAR 2005 OSPAR 05/21/1-E, Annex 7

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