2,2,5-trimethyl-5-pentylcyclopentan-1-one

Short-term toxicity to aquatic invertebrates

Description of key information

OECD Guideline 202, GLP, key study, validity 1:
48h-EC50 (Daphnia magna) = 2.9 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Effect concentration:

2.9 mg/L

Additional information

One valid key study is available to assess the short-term toxicity of the registered substance to aquatic invertebrates, Daphnia magna.

Twenty daphnids per group (four replicates, five daphnids per replicate) were exposed to a control and to 4.6, 10, 22, 46 and 100% of a Water Soluble Fraction (WSF) prepared at a loading rate of 100 mg/L, during 48 hours under static conditions, according to OECD Guideline 202 with GLP statement. Analysis of the samples taken at the start of the final test showed measured concentrations of 0.43, 1.1, 2.0, 4.5 and 10 mg/l at 4.6, 10, 22, 46 and 100% of the WSF, respectively. During the exposure period the measured concentration decreased to 45-54% of initial at the end of the test. This can be due to possible volatilization (VP = 9.2 at 25°C; Henry constant = 95.5 Pa.m3/mol). Based on these results, the average exposure concentrations were calculated to be 0.30, 0.73, 1.4, 3.3 and 6.9 mg/L. After 48 hours of exposure all organisms exposed to the two highest test concentrations were immobilized. No immobility was observed at any of the lower test concentrations. Note that a maximum of 10% immobility is acceptable for the control group. Therefore the 5% immobilisation observed during the current test was considered to be insignificant. In conclusion, under the test conditions, the 48h-EC50 was 2.9 mg/L based on average exposure concentrations.