Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

A toxicity study in algae with the test substance was performed according to OECD guideline 201. The result obtained relevant for C&L was a NOEC value between 1 mg/L to 10 mg/L (1 ≤ NOEC ≤ 10). The results obtained relevant for PNEC derivation were ErC50 (24-72 h) of 9.84 mg/L and a NOEC (24  -72 h) of 3.10mg/L.

Key value for chemical safety assessment

EC50 for freshwater algae:
9.84 mg/L
EC10 or NOEC for freshwater algae:
3.1 mg/L

Additional information

Toxicity to aquatic algae was assessed in a study according OECD guideline 201 with the test substance in concentrations of 0.53, 0.95, 1.7, 3.09, 5.56, 10.0 mg/L. The test substance tends to split immediately to two components in aqueous solution. Its half-life is about 1 hour, and it almost fully decomposes in 5 to 6 hours. Therefore, concentration of the test substance in a test solution was not measured. Thus, the test result was calculated in accordance with a target concentration. Results obtained showed that the growth inhibition concentration by comparison of growth rate for 24 - 72 hours, ErC50 (24 - 72) was 9.84 mg/L, and its 95 % confidence interval was 8.33 - 12.25 mg/L. The NOEC (Velocity method 24-72 hours) was 3.10 mg/L or more. The growth inhibition concentration by comparison of growth rate, ErC50 (24 - 48 hours) was 10.00 mg/L or more and the NOEC (Velocity method 24 - 48 hours) was 10.00 mg/L or more. The growth inhibition concentration by comparison of areas under growth curve, EbC50 (0 - 72 hours) was 3.74 mg/L (95 % Confidence interval: 3.26 mg/L - 4.34 mg/L) and the NOEC (Area method 0-72 hours) was 1.00 mg/L.

The following results were taken into account: EC50 value of 3.74 mg/L and NOEC value of 1.00 mg/L based on biomass, obtained for the whole study exposure period (0-72 hours). On the other hand EC50 value of 9.84 mg/L and NOEC value of 3.10 mg/L based on growth rate, obtained for study exposure period of 24-72 hours (but not 0 -72 hours). When additionally, supposing that minimal change occurred at exposure time 0-24 hours (as no data was available for this time point), it can be assumed that the NOEC value arising from these results and relevant for C&L is between 1 mg/L to 10 mg/L. Thus, the substance is not considered according to these results to be not chronically or acutely harmful for aquatic organisms. ErC50 (24-72 hours) of 9.84 mg/L and NOEC (based on growth rate, 24 -72 hours) of 3.10 mg/L were considered for PNEC calculations being the most suitable available parameters/ results.