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Short-term toxicity to fish

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Description of key information

The substance was acutely toxic to fathead minnow and the 96-hour LC50 value observed in a flow-through test system was 7.7 mg/L.

 

Key value for chemical safety assessment

LC50 for freshwater fish:
7.7 mg/L

Additional information

In a reliable, conclusive and valid study, the effects of the test item 3,5,5-Trimethylhexyl Acetate (CAS #58430-94-7) on fathead minnows (Pimephales promelas) after exposure of 96 hours under flow-through conditions were tested according to OECD TG 203, OPPTS 850.1075 and ASTM Standard E729 -96.

Nominal concentrations were 2.5, 5.0, 10, 20 and 40 mg/L. No oil slicks were observed for test solutions in the test chambers of the 5.0, 10 and 20 mg/L treatment groups, but an oily slick was noted in the 40 mg/L test chambers during the test. The mean measured test concentrations for this study were 0.97, 2.2, 4.0, 6.3 and 11 mg/L, representing 39, 44, 40, 32 and 28 % of nominal concentrations, respectively. The high volatility of the test substance resulted in analytical recoveries that were below 70% in all test concentrations. A flow-through test design was used to provide continuous delivery of the test substance to maximize concentrations. The results of the study are reported based upon the mean measured test concentrations.

All fish in the negative control, solvent control, and in the 0.97, 2.2 and 4.0 mg/L treatment groups appeared normal throughout the test, with no mortalities or overt signs of toxicity observed. Percent mortality in the 6.3 and 11 mg/L treatment groups at test termination was 15 and 100 %, respectively. Lethargy was observed among fish in the 6.3 mg/L treatment group throughout the exposure. Signs of toxicity observed among fish in the 11 mg/L treatment group were lethargy, loss of equilibrium and surfacing. Based on mean measured concentrations, the 96-hour LC50 value was 7.7 mg/L and the no-mortality concentration and the NOEC were 4.0 mg/L.