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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

ErC50(72h) > 100 mg/L 
NOEC(r) >= 100 mg/L
EyC50(72h) > 100 mg/L
NOEC(y) >= 100 mg/L

Key value for chemical safety assessment

EC50 for freshwater algae:
100 mg/L
EC10 or NOEC for freshwater algae:
100 mg/L

Additional information

The acute toxicity to algae of the test substance according to OECD Guideline 201 and EU Method C.3 in a static freshwater test with Desmodesmus subspicatus (former name: Scenedesmus subspicatus) as test organism (Neuhahn, 2011). The study was conducted under certificated GLP compliance. Based on a range-finding study, the definitive test was conducted as "limit test" with a single substance concentration of 100 mg/L. For the test item concentration as well as for the control 6 replicates were prepared. The algal inoculum for the experiment were taken from an exponentially-growing pre-culture and were mixed with the nutrient medium to make up to a final cell density of about 5000 cells/mL in the test medium. During the test a temperature range of 21 - 24 °C was maintained in the vessels. All calculations were carried out using a statistical software program (ToxRatPro Version 2.10). Analysis of the yield and growth rate of the algal population within 72 h exposure period gave the following results: ErC50 (72h) > 100 mg/L and EyC50 (72 h) > 100 mg/L, as well as NOEC(r) >= 1000 mg/L and NOEC(y) >= 100 mg/L. Effective concentrations correspond to 89.2 % of nominal values at 72 h.

Additionally a prediction for long-term toxicity to green algae was performed with the computer program ECOSAR v1.00 (EPIWIN software) by US-EPA (Chemservice S.A., 2011). The program uses an extensive set of structure-activity relationships (SARs) to estimate the toxicity of chemicals discharged to water. For green algae a Chronic Value (ChV) of 70.66 mg/L was predicted. No GLP criteria are applicable for the usage of this tool, but due to the fact that it is a scientifically accepted calculation method the estimations performed are reliable with restrictions, but cannot be used for the chemical safety assessment.

According to the available data, the test substance is not classified as toxic to aquatic algae.