Climbazole

Long-term toxicity to aquatic invertebrates

Description of key information

Daphnia magna was tested in a semi-static test system following OECD guideline no. 211 over 21 days. The NOEC (reproduction) was determined to be 0.2 mg/L and the LOEC (reproduction) was determined to be 0.4 mg/L.

Key value for chemical safety assessment

Fresh water invertebrates

Fresh water invertebrates

Dose descriptor:

NOEC

Effect concentration:

0.2 mg/L

Additional information

The effect of the test substance on the reproduction of Daphnia magna was studied in a valid GLP study according to OECD 211. The test was performed under semi-static conditions over 21 days. The daphnids (10 animals) were exposed to six different concentrations (0.025, 0.05, 0.1, 0.2, 0.4 and 0.8 mg/L). As the test concentrations were stable (analytical verification: recovery 94 to 115%) the effect concentrations were based on nominal concentrations.

The offspring produced by each parent animal were removed and counted daily from the appearance of the first brood. The mean number of living offspring in the test concentrations of 0.025 to 0.2 mg/L were higher than the corresponding control value, whereas it was significantly reduced at the two highest test concentrations (0.4 mg/L: 75.8 % and to 0.8 mg/L: 100 %). Significant reduced No. of living juveniles per parent animal produced per day (from the day of the first offspring on) were obtained with the test groups treated with 0.4 and 0.8 mg/L compared to the untreated control.

The additionally recorded time from the production of first brood until the end of the test showed significant differences of the values at the concentrations of 0.2, 0.4 and 0.8 mg/L from the control.

Besides the offspring counting other parameter were examined: microscopic examination of the newborns, presence of aborted eggs, aborted offspring, dead newborns and behavioral changes.Significantly higher numbers of aborted eggs and dead newborns were noticed in the concentrations of 0.4 and 0.8 mg/L. The presence of male neonates or ephippia was not noticed. Reduced activity of the newborns was noticed at the concentration of 0.2 mg/L.10 % mortality among the parent animals was observed during the testat the concentration of 0.05 mg/L, but as this value was within the acceptance range of the control, it was evaluated as non test item-related effect. No significant difference between the measured body length values of the daphnia exposed to the test substance and the measured values of the untreated animals were found.

The highest concentration tested without showing a toxic effect on reproduction after the 21-day exposure period (=NOEC) was determined as 0.2 mg/L and the determined LOEC was 0.4 mg/L.