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 EC50 for the test substance, both in terms of biomass, growth rate and yield were found to be greater than 105 mg/L over the 72-hour test period.  The no-observed effect concentration (NOEC) over this period could not be calculated, but must be 105 mg/L with levels of inhibition of at most 6%

Key value for chemical safety assessment

Additional information

An Algal Growth Inhibition Assay was conducted by Huntingdon Life Sciences Ltd, UK, to determine the effect of the test substance on aquatic algae. The study was conducted in accordance with OECD and EC test guidelines, and in compliance with GLP.

Six algal cultures, with an initial nominal cell density of 1 x 104/mL, were exposed to the test substance at a nominal concentration of 100 mg/L. The test medium was prepared in OECD medium by the direct addition of the test substance to the dilution medium; to aid dispersion, the test medium was treated by ultrasound for 15 minutes before use. The cultures were incubated in an orbital incubator under continuous illumination at temperatures ranging from 21.4 to 22.5°C for 72 hours.

The mean measured level of the test substance in samples of the test cultures ranged from 109% of the nominal value at the start of the test to 102% after 72 hours (93% of the starting value), giving an overall mean measured level of 105 mg/L. Cell numbers were counted daily to monitor growth. The test results are expressed in terms of the area under the growth curve, growth rate and yield.

After 72 hours of exposure to the test substance, the EbC50, ErC50 and EyC50 could not be calculated, but must be >105 mg/L with levels of inhibition of at most 6%. The “no observed effect concentration” (NOEC) for area under the growth curve, growth rate and yield was 105 mg/L.