β,4-dimethylcyclohex-3-ene-1-propan-1-al

Toxicity to aquatic algae and cyanobacteria

Description of key information

The study was conducted to determine the inhibitory effect of the Limoxal on the growth of the freshwater green algae Pseudokirchneriella subcapitata according to the OECD Guideline 201 in compliance with GLP. Exponentially growing algal cells were exposed for a period of 72 hours to a range of concentrations, nominally 10, 5, 2.5, 1.25 and 0.63 mg test item/L (spacing factor 2), and a control, corresponding to the following geometric mean measured concentrations of the test item: 6.35, 2.49, 1.11, 0.426 and 0.0252 mg test item/L and a control. This study encompassed 6 treatment groups (5 concentrations of the test item and a control) with three replicates per test concentration and six replicates for the control. At test start 50 mL of the test media were inoculated with nominal 5000 algal cells per mL test medium and defined volumes of the algal suspensions were sampled after 24, 48 and 72 hours for determination of cell densities by spectrophotometric measurement. Yield (y) and growth rate (r) of the algae were determined. The initial concentrations and the maintenance of the exposure concentrations during the test were assessed in the analytical part. All reported results refer to geometric mean concentrations, since the test item concentrations were not within ± 20% of the nominal or measured initial concentrations during the test. Under the study conditions, the 72-hour ErC50 value was calculated to be 5.88 mg test item/L. The 72-hour ErC10 was determined to be 3.04 mg test item/L.

Key value for chemical safety assessment

EC50 for freshwater algae:

5.88 mg/L

EC10 or NOEC for freshwater algae:

3.04 mg/L