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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

The test item FAT 60'253/A had no inhibitory effect on the growth (biomass and growth rate) of Scenedesmus subspicatus during the exposure period of 72 hours up to and including the undiluted filtrate with the mean measured test item concentration of 0.018 mg/l (loading rate of 100 mg/l). Thus, this test concentration was determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours)

Key value for chemical safety assessment

EC10, LC10 or NOEC for freshwater algae:
0.018 mg/L

Additional information

The influence of the test item FAT 60'253/A on the growth of the green algal species Scenedesmus subspicatus CHODAT was investigated in a 72-hour static test according to the Commission Directive 92/69/EEC, C.3,1992, and the OECD Guideline No. 201, 1984.

Due to the very low water solubility of the test item, a super saturated stock dispersion of the test item with a loading rate of nominal 100 mg/l was continuously stirred at room temperature in the dark over 7 days. Then, the dispersion was filtered. The undiluted filtrate with the maximum concentration of dissolved and very finely dispersed test item and the dilutions 1:2.2, 1:4.6, 1:10, and 1:22 were used as test media. Additionally, a control was tested in parallel.

The test item FAT 60'253/A had no inhibitory effect on the growth (biomass and growth rate) of Scenedesmus subspicatus during the exposure period of 72 hours up to and including the undiluted filtrate with the mean measured test item concentration of 0.018 mg/l (loading rate of 100 mg/l). Thus, this test concentration was determined as the 72-hour NOEC (highest concentration tested without toxic effects after a test period of 72 hours). The NOEC might even be higher but concentrations of the test item above the maximum concentration which could be dissolved or very finely dispersed in the test water were not tested, according to the guidelines. The 72-hour LOEC (lowest concentration tested with toxic effects) and the 72-hour EC50 for the algal biomass b and the growth rate u were clearly higher than the solubility limit of the test item in the test water. These parameters could not be quantified due to the absence of a toxic effect of FAT 60'253/A up to the highest test concentration which could be dissolved or very finely dispersed in the test water.