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Ecotoxicological information

Toxicity to aquatic plants other than algae

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Description of key information

ErC50 (Lemna minor, 7d, frond number) > 100 mg/L (nominal)

Key value for chemical safety assessment

EC50 for freshwater plants:
100 mg/L

Additional information

This study was performed in order to evaluate the toxicity of tehe test item towards Lemna minor following the OECD Guideline 221 (2006). The study was performed using 5 concentrations ranging from 4.6 to 100 mg/L. Incubation time was 7 days. The frond number of each replicate was determined at the beginning, at day 2 and 5 during the test and at the end of the experiment. Additionally, the dry mass of 12 representative fronds was determined at the beginning of the experiment. At the end of the experiment the dry mass of each replicate was determined. Growth rate µ and the yield were determined from the frond number and the drymass at the respective observation times.

Significant inhibition of plant growth was observed at the following concentrations: 10 (only yield dry mass), 22, 46 and 100 mg/L.

At the start and at the end of the test, the content of the test item in the test solutions was determined using photometer.

The measured concentrations lay between 94 % and 100 % of the nominal concentrations at the beginning of the test and between 92 % and 103 % of the nominal concentrations at the end of the test. Therefore, the determination of the results was based on the nominal concentration.

For the estimation of the EC50s of the test item, the fits showed sufficient statistical correspondence of the data with the dose-response-equation.

The 7d-EC50s of the positive control were determined in a separate reference test. The values lay within the desired range.

The pH of the blankcontrolshould not vary by more than 1.5 units. The change was 1.2 units in the blank control.

All validity criteria were met.

No observations were made which might cause doubts concerning the validity of the study outcome. The result of the test can be considered valid.

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