Daphnia magna

In order to meet the requirements of the REACH legislation alternative approaches, providing experimental data and based on the 3R principles (Replace, Reduce and Refine animal testing), are necessary

ENNSATOX is a small collaborative project, funded by the EU under the 7th Framework's NMP Theme.

Aquatic toxicity information is essential in environmental risk assessment to determine the potential hazards of risks of new and existing chemicals.

Daphnia magna, a frequently used standard organism in laboratory toxicity testing was chosen for this study. In laboratory toxicity testing it is often assumed that organisms will respond in a similar manor as in a field situation. However, in realistic environments multiple factors and stressors, such as the differences in temperature, food availability, etc.... may strongly interfere with responses to pollutant stress. Moreover, organisms are almost always exposed to mixtures of chemical stressors in natural situations. From a toxicological point of view, these interactions can highly influence the overall impact of chemical stressors.

The number of chemical products produced by men is enormous. At present the number of chemicals registered by the Chemical Abstract Service exceeds 20 million. Estimations are that over 100.000 compounds are released in the environment in such volumes that they generate a potential threat for men and environment. Only little is known on the toxicological properties of this large group of chemicals. The scarce information available until now consists mainly of acute toxicity data. Long term adverse effects on populations, communities and ecosystems are poorly documented. The lack of chronic and long term data is illustrated by the phenomenon of endocrine disruption. Various chemicals are capable of interfering with the endocrine metabolism of several animal species leading to negative effects on their reproduction. There is a great deal of uncertainty about the possible adverse (endocrine disrupting) character of chemicals for men and environment due to the scarce availability of chronic toxicity data and restricted knowledge on the toxicological working mechanisms. Especially for the ecologically important group of invertebrates no clear assays for mechanistic evaluation of endocrinological pathways disruption are developed yet. It is clear that there is an urgent need for this kind of assays to provide both chronic relevant as well as mechanistic detailed data.