The European Union Reference Laboratory for Alternatives to Animal Testing (EURL ECVAM) of the European Commission's Joint Research Centre has published an article on the possible use of a simple modelling approach to avoid the need for chronic fish testing in chemical risk assessment.
The assessment of aquatic toxicity is an important component of the environmental hazard and risk assessment of all types of chemicals, and is therefore included in several pieces of EU chemicals legislation.
Aquatic toxicity is usually determined by testing on organisms representing the three trophic levels:
- plants (or algae),
- invertebrates (crustaceans such as Daphnia spp.) and
- vertebrates (fish)
Whereas acute aquatic toxicity testing is a basic requirement in most pieces of EU chemicals legislation, chronic aquatic toxicity testing may be required on a case by case basis, for example when the outcome of the acute testing indicates a risk, or when long-term exposure to the chemical is expected.
However, in accordance with EU Directive 2010/63 on the protection of animals used for scientific purposes, all available information should be considered before testing on vertebrates, including fish, is carried out.
In this context, the JRC has explored the utility of simple extrapolation approaches, based on existing aquatic toxicity data, for avoiding chronic fish testing.
Acute and chronic toxicity data for Daphnia and fish were extracted from various databases and analysed to identify possible relationships taking into consideration the chemical mode of action.
The results of this analysis indicate that interspecies extrapolations based on invertebrate (Daphnia) data could support the waiving of chronic fish toxicity test in low-tier risk assessments, especially for chemicals acting by unspecific reactivity and non-polar narcosis. Acute-to-chronic extrapolations from existing acute fish toxicity data are also recommended as a means of deriving information on chronic fish toxicity without the need to perform additional fish tests, irrespective of the chemical’s mode of action.
Read more in: Kienzler et al "Waiving chronic fish tests: possible use of acute-to chronic relationships and interspecies correlations", Toxicological and Environmental Chemistry 99 (2017) 1129-1151, doi: 10.1080/02772248.2016.1246663
- 7 september 2017