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Short-term toxicity to aquatic invertebrates

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Description of key information

3-hydroxy-1,1-dimethylbutyl 2-ethyl-2-methylheptaneperoxoate did not induce acute immobilization of Daphnia magna at or  below 1.8 mg/L after 48 hours of exposure (NOEC) with a 48h-EC50 of 4.8  mg/L (95% confidence interval between 4.2 and 5.8 mg/L).

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates
Effect concentration:
4.8 mg/L

Additional information

Daphnia were exposed in a semi-static test for a maximum of 48 hours to a concentration range of 1.0 to 10 mg/L forming a geometric progression with a factor of 1.8. The test was performed in duplicate with 10 daphnia per vessel. Since 3-hydroxy-1,1-dimethylbutyl 2-ethyl-2-methylheptaneperoxoate was expected to degrade in light, the test was performed in the dark. Analytical confirmation of test concentrations was not performed, owing to problems with the detection of 3-hydroxy-1,1-dimethylbutyl 2-ethyl-2-methylheptaneperoxoate in water samples at the concentrations tested.

After 24 hours of exposure no immobilization of daphnia was seen in any of the concentrations tested.

Alter 48 hours of exposure immobilization of all daphnia exposed was seen at a concentration of 10 mg/L, while 55% of the daphnia exposed to 5.6 mg/L and 15% at 3.2 mg/L became immobilised. No immobilization of daphnia was seen at or below1.8 mg/L.

The 48h-EC50 was calculated to be 4.8 mg/L with 95% confidence interval ranging frorn 4.2 to 5.8 mg/L based on nominal concentrations (regression fine: log10(conc.)=0.26 +(probit-2.815)/5.11). Finally, NOEC for 3-hydroxy-1,1-dimethylbutyl 2-ethyl-2-methylheptaneperoxoate with respect to mobility of Daphnia magna was found to be 1.8 mg/1 after 48 hours of exposure.