3-methyl-5-(2,2,3-trimethyl-3-cyclopenten-1-yl)pent-4-en-2-ol

Short-term toxicity to fish

Description of key information

The acute toxicity of Ebanol to the freshwater fish fathead minnow (Pimephales promelas) has been investigated and gave a 96-Hour LC50 value of 2.3 mg/l with 95% confidence limits of 1.7 - 3.0 mg/l.  The No Observed Effect Concentration was 0.96 mg/l.

Key value for chemical safety assessment

Fresh water fish

Fresh water fish

Effect concentration:

2.3 mg/L

Additional information

Following a preliminary range-finding test, fish were exposed to an aqueous solution of the test item over a range of nominal concentrations of 0.30, 0.54, 0.96, 1.7 and 3.0 mg/l for a period of 96 hours at a temperature of approximately 21ºC under semi-static test conditions involving daily renewal of the test preparations. The test item solution was prepared by stirring an excess (100 mg/l) of the test item in dechlorinated tap water with the aid of propeller stirring at approximately 1500 rpm for 24 hours. After the stirring period, the undissolved test item was removed by filtration to give a saturated solution with a nominal test concentration of 30 mg/l. Dilutions were prepared, in dechlorinated tap water, from this saturated solution to give the remainder of the test series. Samples for analytical confirmation of actual exposure concentrations were taken at the start and the end of the first and last refreshment period.

Analysis of the saturated solution, used to prepare the test concentrations, at 0 and 72 hours showed measured concentrations of 25.7 and 32.5 mg/l respectively (86% and 108% of nominal respectively). The results from the freshly prepared media at 0 and 72 hours showed measured concentrations to range from 80% to 102% of nominal. Results from the old media at 24 and 96 hours showed a decline in measured concentrations over the 24-Hour dosing periods with results ranging from 48% to 87% of nominal. 

The test item is known to be stable in the test media over a 24-Hour period and has also been shown to be stable over a 72-Hour period for the Algal Inhibition study (Harlan Laboratories Ltd Project Number: 0766-0176). As both tests conducted were similarly covered, losses due to volatilisation were not expected. It was therefore considered that the decline in measured concentrations over the 24-Hour dosing periods was possibly due to adsorption to the test organisms and/or organic waste. It was therefore considered justifiable to base the results on nominal test concentrations only.

The study met the acceptability criteria prescribed by the study plan and was considered valid.

The 96-Hour LC₅₀based on nominal test concentrations was 2.3 mg/l with 95% confidence limits of 1.7 - 3.0 mg/l. 

The No Observed Effect Concentration was 0.96 mg/l.