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Toxicity to aquatic plants other than algae

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Description of key information

ErC50 (Lemna minor, 7d, frond number) > 47.96 mg/L (meas. (geom. mean))

Key value for chemical safety assessment

Additional information

The acute toxicity of the test item to aquatic plants was investigated in a 7–day static test to Lemna minor, according to the OECD Guideline 221 (2006). The study was performed using 6 concentrations ranging from 0.32 to 100 mg/L (nominal concentration). The frond number of each replicate was determined at the beginning, at day 3 and 6 during the test and at the end of the experiment. Additionally, the dry mass of each replicate was determined at the beginning and at the end of the experiment. Growth rate µ and the yield were determined from the frond number and the dry mass at the respective observation times.

At the end of test, replicates with and without plants were analysed. The measured concentrations in the replicates with and without plants are in the same range. Therefore, the measured values in the replicates without plants were used for evaluation.

The measured concentrations lay between 22 % and 47 % of the nominal concentrations at the beginning of the test and between 20 % and 51 % of the nominal concentrations at the end of the test (without plants). Therefore, the determination of the NOEC / LOEC / ECx was based on the geometric mean of the measured concentrations. The 7d-EC50 values of positive control were determined in a separate reference test; the value of the growth rate lay within the desired range of 1.7 - 5.7 mg/L.