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Ecotoxicological information

Toxicity to aquatic plants other than algae

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Description of key information

ErC50 > 102 mg/l a.i. based on frond number and dry weight

Key value for chemical safety assessment

Additional information

The growth inhibitory effects of the test item to the duckweed Lemna minor were investigated according to test guideline OECD 221, under static conditions over a period of 7 days.

The test solutions were prepared by respective dilutions of a stock solutionin Swedish Standard medium.

The test was performed at 162, 51.3, 16.2, 5.13 and 1.62 mg/l nominal concentration of the test item, corresponding to100, 31.6, 10, 3.16 an d 1.0 mg/lof 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 indicated that the concentrations of the test item were stable over the whole 7-day period, but that the two lowest concentrations were not within 80-120 % of the nominal concentrations. Therefore, the effective concentrations (ErC50and EyC50) 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 7-day ErC50 (based on frond number) of the test item on the duckweed Lemna minor is > 102 mg/l. This value is based on the measured concentrations of the active ingredient.