Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

The 72-hour NOEC and ErC50 for Pseudokirchneriella subcapitata (formerly Selenastrum capricornutum) exposed to Unoxol 3,4 Dialdehyde was 1.7 and 17 mg/L, respectively.

Key value for chemical safety assessment

EC50 for freshwater algae:
17 mg/L
EC10 or NOEC for freshwater algae:
1.7 mg/L

Additional information

In a valid toxicity study with Pseudokirchneriella subcapitata (Klimisch score = 1), algal cells were exposed to nominal test concentrations of 0, 4.6, 10, 22, 46 and 100 mg/LUnoxol 3,4 Dialdehyde. Measured test concentrations were determined from samples of test medium collected from each treatment and control group at the beginning, at 24 hours, and at end of the test (72 hours). At the end of the test, measured concentrations remained stable for the two highest test concentrations, while a significant and concentration dependent decrease was observed in samples taken from the three lowest concentrations. Based on these results, the time weighted average exposure concentrations were calculated to correspond to 1.7, 5.5, 21, 47, and 105 mg/L. Samples were collected from each replicate test chamber at approximately 24-hour intervals during the test to determine cell densities. Areas under the growth curve and growth rates were used to calculate percent inhibition values relative to the control over the 72 -hour exposure period. The 72-hour NOEC and EC50 based on growth rate were 1.7 and 17 mg/L, respectively. The 72-hour NOEC and EC50 based on biomass were <1.7 and 5.9 mg/L, respectively. Since the use of the average specific growth rate for estimating toxicity is scientifically preferred (OECD 201), this toxicity value was selected as key for this endpoint.