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Short-term toxicity to aquatic invertebrates

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Description of key information

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
367 mg/L

Additional information

The acute toxicity (inhibition of mobility) of AZDN was assessed in Daphnia magna exposed for 24 and 48 hours, according to the procedure described in Method C.2 of Directive 92/69/EEC. Daphnia were exposed in static conditions to a range of concentrations of AZDN (160 - 367 mg/l) for up to 48 hours. The highest concentration of AZDN used (367 mg/l) did not show a significant immobilisation in Daphnia magna following the 48 hours exposure. The validity criteria for the study have been met, the immobilisation in the control did not exceed 10% at the end of the test and the concentration of dissolved oxygen remained above 2 mg/l at the end of the test. The pH did not vary by more than 1 unit and the concentrations of the test substance were maintained to within 80% of the initial concentration over the duration of the test.

In the second study, the results obtained after exposure for 24 hrs were that 50% immobilization concentration (EiC50) was >10 mg/L, and the 50% immobilization concentration (EiC50) at 48 hrs was also >10 mg/L. The maximum no-observed-effect concentration (NOECi) was 10 mg/L and the minimum 100% immobilization concentration was found to be >10 mg/L. These concentrations are based on the nominal concentrations of the test substance to which Daphnia magna were exposed.

Nevertheless, as no higher concentration was tested the picture cannot be considered as complete. The study is therefore disregarded.