ABSTRACT
BACKGROUND: Engineered nanomaterials (ENMs) are marketed as a substance or mixtures and are additionally used due to their active agent properties in products such as pesticides or biocides, for which specific regulations apply. Currently, there are no specific testing strategies for environmental fate and effects of ENMs within the different regulations. An environmental test and risk assessment strategy for ENMs have been developed considering the general principles of chemical assessment. RESULTS: The test strategy has been developed based on the knowledge of national and international discussions. It also takes into account the conclusions made by the OECD WPMN which held an expert meeting in January 2013. For the test strategy development, both conventional and alternative endpoints were discussed and environmental fate and effects were addressed separately. CONCLUSION: A tiered scheme as commonly used in the context of precautionary environmental risk assessment was suggested including the use of mathematical models and trigger values to either stop the procedure or proceed to the next tier. There are still several gaps which have to be filled, especially with respect to fate, to develop the test strategy further. The test strategy features a general approach. It is not specified to fulfil the information requirements of certain legislation (e.g. plant protection act, biocide regulation, REACH). However, the adaption of single elements of the strategy to the specific needs of certain legislation will provide a valuable contribution in relation to the testing of nanomaterials.
ABSTRACT
This paper details the derivation of a list of 60 reference chemicals for the development of alternatives to animal testing in ecotoxicology with a particular focus on fish. The chemicals were selected as a prerequisite to gather mechanistic information on the performance of alternative testing systems, namely vertebrate cell lines and fish embryos, in comparison to the fish acute lethality test. To avoid the need for additional experiments with fish, the U.S. EPA fathead minnow database was consulted as reference for whole organism responses. This database was compared to the Halle Registry of Cytotoxicity and a collation of data by the German EPA (UBA) on acute toxicity data derived from zebrafish embryos. Chemicals that were present in the fathead minnow database and in at least one of the other two databases were subject to selection. Criteria included the coverage of a wide range of toxicity and physico-chemical parameters as well as the determination of outliers of the in vivo/in vitro correlations. While the reference list of chemicals now guides our research for improving cell line and fish embryo assays to make them widely applicable, the list could be of benefit to search for alternatives in ecotoxicology in general. One example would be the use of this list to validate structure-activity prediction models, which in turn would benefit from a continuous extension of this list with regard to physico-chemical and toxicological data.
