Reaction mass of 3,5,6,6-tetramethyl-4-methyleneheptan-2-one and (E)-3,4,5,6,6-pentamethylhept-3-en-2-one

Short-term toxicity to fish

Description of key information

An OECD TG 203 guideline study in compliance with GLP with carp (Cyprinus carpio) is available for the test substance. Fish (7/dose) were exposed to nominal concentrations of 0.46, 1.0, 2.2, 4.6, and 10 mg/L under semi-static conditions for 96 hours. Because the test substance is volatile the exposure was performed in air-tight closed vessels with a headspace reduced to a minimum. Analysis of the samples taken at the start of the test showed measured concentrations of 3.1 and 7.3 mg/L at the nominal concentrations of 4.6 and 10 mg/L, respectively. After 48 hours of exposure the test substance concentrations measured remained constant (80-91% of initial). Analysis of samples taken during the last refreshment period confirmed previous results. Based on these results the effect parameters were expressed on the basis of initially measured concentrations. Besides the highest concentration tested no mortality or clinical effects were observed in the control and remaining concentrations. From the beginning of exposure fish in the highest concentration were immobilized. Three fish died within the first 24 hours of exposure and total mortality was reached at the 72 hour of exposure. The study met the acceptability criteria prescribed by the protocol and was considered valid. Since measured concentrations deviated by more than 20% from nominal, results were based on the initially measured concentrations. The 96-h LC50 value is 4.8 mg/L (95% C.L. is 3.1 to 7.3 mg/L).

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Dose descriptor:

LC50

Effect concentration:

4.8 mg/L