Suchergebnisse

In July 2013, the Fish Embryo Acute Toxicity Test (FET) was adopted by OECD as Test Guideline 236. The FET thus represents the first fully validated alternative method within the OECD Test Guidelines Programme in the ecotoxicology sector. However, the practical applicability of the FET has ever since been discussed with respect to a series of aspects, which are addressed in this report: With respect to the potential barrier function of the zebrafish chorion, the molecular size for a free passage of non-charged chemical substances across the chorion of the zebrafish could be set at 3,000 - 4,000 Da. The limit for the passage of charged molecules is lower than that of non-charged ones. DMSO concentrations of ≥ 0.1 % decrease the barrier function of the chorion. Zebrafish embryos, juveniles and adults have been studied to a different extent with respect to their biotransformation capacities. Our knowledge on biotransformation capacities in zebrafish is fragmentary. On this basis, transfer of biotransformation data from juvenile to adult fish is not possible. In zebrafish embryos, biotransformation could be documented whenever studied in more detail; only for rare exceptions, lack of biotransformation was demonstrated. Gene activation cannot be translated into biochemical functionality; mammalian data cannot be extrapolated to fish. The analysis of historical short-term (acute) Fish Toxicity Test (AFT) data produced according to OECD TG 203 within a dataset used for a corresponding FET study by ECHA started with 2936 studies on a total of 1842 substances. Applications of filters identical to those used for the FET analysis resulted in exclusion of 62.3 % of the AFT studies and 63.0 % of the substances. Data of the present report will be integrated into OECD project no. 2.54: "Guidance Document on an Integrated Approach on Testing and Assessment for Fish Acute Toxicity Testing" - Integration of the Fish Embryo Test into the Threshold Approach".

The OECD Test Guidelines (TG) for Chemicals are a specific tool for assessing the potential effects of chemicals on human health and the environment. These internationally standardised TGs for the testing of chemicals are used by industry, academia and authorities in the testing and evaluation of chemicals (industrial chemicals, pesticides, biocides, pharmaceuticals, etc.). As part of the OECD Test Guidelines Programme (TGP), the OECD TGs are developed and updated by the OECD Working Group of National Coordinators for the OECD Test Guidelines Programme (WNT). To ensure that the OECD TGs reflect the state of the art in science and technology and meet the regulatory requirements of member countries, the OECD TGs are to be continuously expanded and updated. As regular review of the OECD TGs is not a standard requirement, it is the responsibility of OECD member countries to identify, propose and implement the projects necessary to update the TGs. Therefore, the focus is often on guidelines in which member countries have a particular interest and for which sufficient resources are available to initiate a revision process. Test guidelines that may not be used as frequently or are of low interest tend to be neglected in this approach, although a revision may be necessary. The aim of this project was to identify OECD TGs that are not state of the art. Only OECD TGs that refer to the effects of chemicals on biotic systems, to the behaviour and fate of chemicals in the environment or to their physicochemical properties when used for environmental risk assessment were considered. Based on a detailed questionnaire, a comprehensive survey was conducted to identify the needs for TG revisions. Proposals for revising the TGs were evaluated in a second survey. Both surveys were open to all interested parties including industry, science, contract labs, NGOs and authorities. After completion of the surveys, the results were discussed in three thematic workshops. Recommendations for the revision of the OECD Test Guidelines were developed and prioritised, which were finally presented to the members of the WNT.