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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

Key value for chemical safety assessment

EC50 for freshwater algae:
4.81 mg/L
EC10 or NOEC for freshwater algae:
1.67 mg/L

Additional information

In the Klimisch 1 GLP study from Scheerbaum (2001) the growth of Scenedesmus subspicatus was determined in the presence of Chloracetamide.For the test interval from 0 -72 hours, the validity cirteria from OECD 201 (2006) were not met. The data were re-evaluated to meet the criteria outlined in the updated guideline from 2006. A new evaluation after 48 hours was carried out according to OECD-Guideline No. 201 (2006) and added as amendment to final report. The 48 hours exposure period meets the validity criteria of the guideline for the time interval from 0 - 48 hours. This scenario is foreseen in the guideline from 2006 (Page 2, section 11 of the guideline states: "The test period may be shortened to at least 48 hours to maintain unlimited, exponential growth during the test as long as the minimum multiplication factor of 16 is reached.") Since the validity criteria were fulfilled, the results are considered reliable. Hence, the 48 hour results as provided in the amendment of the final report were reported here.

The test was performed with Scenedesmus subspicatus (new name: Desmodesmus subspicatus) at a control and nominal 0.313, 0.625, 1.25, 2.5, 5 and 10 mg test item/L. Six control replicates and three replicates were set up for each treated test group. The cell density was measured via Chlorophyll-a-fluorescence (excitation at 435 nm, emission at 685 nm). The 48 hour-EC10 and EC50 values based on nominal concentrations were 1.67 and 4.81 mg/L, respectively.

The results are considered relevant and reliable for the risk assessment.