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

ECr50 = 192 mg/l based on frond number and dry weight

Key value for chemical safety assessment

Additional information

No studies on the "toxicity to aquatic plants other than algae" are available for the substance in itself.

Nevertheless a study have been conducted with an analogue molecule (Similar Substance 03). Further information are reported in the Read Across justification attached to section 13.

The inhibitory effects of the test substance to the duckweed Lemna minor were investigated over a period of 7 days, based on the frond number and biomass (dry weight), following the guideline OECD 221.

The test solutions were prepared by respective dilutions of a stock solution in SIS Medium. The test was performed at 230, 72.8, 23.0, 7.28 and 2.30 mg/l nominal concentration, corresponding to 150, 47.4, 15.0, 4.74, 1.50, and 0.474 mg/l of the active ingredient.

Three parallel test vessels were used for each test concentration of the test item and six vessels for the blank controls.

The test concentrations during the 7 day test period were determined by photometry at the beginning of the test, as well as after 3, 5 and 7 days of exposure. These analyses confirmed the right dosage of the test item, and showed that the concentrations of the test item remained stable over the whole 7 day test period. However, the lowest concentrations did not remain in the 80-120 % range of the nominal concentration. Therefore, the effective concentrations (ErCx and EyCx) were assessed based on the geometric mean (GM) of the measured concentrations of the active ingredient.

The two endpoints frond number and biomass (dry weight) were investigated at days 3, 5 and 7, and each of them were assessed as growth rate and yield.

The ERx50 values based on growth rate were:

ECr50 = 192 mg/l based on frond number

ECr50 = 192 mg/l based on dry weight