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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

Key value for chemical safety assessment

LC50 for freshwater fish:
100 mg/L

Additional information

The lethality effect of AZDN was assessed in Danio rerio exposed for 24, 48, 72 and 96 hours according to the procedure described in Method C.1 of Directive 92/69/EEC corresponding to OECD Guideline No 203.

At 100 mg/l AZDN did not show any mortality in the fish species used, the LC50-96h was >100 mg/l.

The validity criteria for the study have been met, the mortality in the control did not exceed 10% at the end of the test and the concentration of dissolved oxygen remained above 60% of the air saturated value 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 involving Oryzias latipes, the median lethal concentration (LC50) of 2-2’-azobis (2-methylpropanitrile) at 96 hrs based on its selected concentration was >10 mg/L. Nevertheless, as no higher concentration was tested the picture cannot be considered as complete. The study is therefore disregarded.

Lethal and sub-lethal effects of AZDN were assessed in Oryzyas latipes exposed for 14 days according to the procedure described in OECD Guideline No 204. At 10 mg/l AZDN did not show any mortality in the fish species used, the LC50 -14d was >10 mg/l.

The fish were observed over the test period for differences in weight, length, behaviour and mortality. At the end of the 14 day exposure period, the no overall effect concentration NOEC was found to be = 10 mg/L.