Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to aquatic plants other than algae

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

Two aquatic plant (other than algae) studies were conducted. In the first study (Maki 1981), the long term toxicity of C11.6LAS to the aquatic plant (Elodea canadensis) was determined in a 28 day model ecosystem test. The nominal test concentrations were 0.5, 1.0, 2.0, and 4.0 mg/L, and were confirmed by analytical measurements.Growth inhibition was not observed even at highest tested concentration (4 mg/L). Growth throughout the exposure period approximately doubled the initial biomass of the vegetative shoots used at the start of the exposure. Hence, the NOEC was found to be>4 mg/L. The data are for C11.6 LAS and no normalization is required.

In the second study (Bishop and Perry 1981; Bishop 1980; van de Plassche et al 1999), the duckweed, Lemna minor, was exposed to C11.8LAS. Endpoints included frond count, dry weight, growth rate, and root length after a 7 day exposure period in a flow through study. The measured test concentrations were 0, 2.1, 3.8, 8, 17 and 34 mg/L. The resultant EC10value, based on frond number, was 0.21 mg/L. The EC50value, also based on frond number, was 2.30 mg/L C11.8LAS. Normalizing the EC10of 0.21 mg/L to C11.6LAS results in a final value of 0.30 mg/L.

Key value for chemical safety assessment

Additional information

In general, algae were not affected by C12LAS or increased in density, particularly blue-green algae, and autotrophic activity increased with increasing C12 LAS. In contrast, some invertebrates declined in density at concentrations >0.293 mg/L, as a result of increasing drift from the shock of the initial dose or from long-term toxicity and habitat changes. Microbes acclimated to mineralizing C12 LAS. Overall, the heterotrophic periphyton community remained robust and did not change their food (amino acid) uptake rate.