Cyclopentanol, 2-pentyl-, (1R,2S)-rel-

Toxicity to aquatic algae and cyanobacteria

Description of key information

EU Method C.3, OECD Guideline 201, GLP, key study, validity 2:
72h-ErC50 = 14.0 mg/L (95% confidence interval: 11.3 -17.5 mg/L).
72h-ErC10 = 4.6 mg/L (95% confidence interval: 2.8 -6.2 mg/L).
72h-NOECr = 1.7 mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

14 mg/L

EC10 or NOEC for freshwater algae:

1.7 mg/L

Additional information

One key study is available to assess the influence of the registered substance on the growth of the freshwater green algal species Pseudokirchneriella subcapitata in a 72h static condition, according to the EU Method C.3 and the OECD Guideline 201 with GLP statement.

The nominal concentrations of the test substance of 0.32, 1.0, 3.2, 10, 32 and 100 mg/L were tested in parallel with a control. Since the test substance was determined to be volatile, the test was performed in a closed system to avoid losses of the volatile substance.

The measured concentrations of the test substance in the test media samples were between 63 and 107% of nominal values at the start of the test. During the test period of 72 hours, a decrease of test substance concentration in the test media occurred at least in the lower test concentrations. The mean measured test concentrations (calculated as the geometric means of the concentrations measured at the start and the end of the test) were between 21 and 101% of nominal values.

The biological results were related to the mean measured test substance concentrations, which were 0.10, 0.21, 1.7, 6.6, 22 and 101 mg/L, respectively, corresponding to the nominal test item concentrations mentioned above. Unfortunately, the geometric spacing of critical measured concentrations between 15 and 72% effects was greater than a factor of 3.2 as recommended in the guideline due to substance loss at the lower concentration.

Based on the growth rate, the 72h-ErC10 and 72h-ErC50 were determined to be 4.6 mg/L (95% confidence interval: 2.8 -6.2 mg/L) and 14.0 mg/L (95% confidence interval: 11.3 -17.5 mg/L), respectively. The 72h-NOEC was 1.7 mg/L.

All validity criteria were fulfilled. In the control, the biomass increased by a factor of 214 over 72 hours. The mean coefficient of variation of the daily growth rates in the control (section by section growth rates) during 72 hours was 18.4% and the coefficient of variation of the average specific growth rates in the replicates of the control after 72 hours was 2.3%.