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Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

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Description of key information

72h EC50 (Desmodesmus subspicatus; growth rate) = 34 mg/L (nominal concentration, DIN 38412 (9))
72h EC10 (Desmodesmus subspicatus; biomass) = 19 mg/L (nominal concentration, DIN 38412 (9))

Key value for chemical safety assessment

EC50 for freshwater algae:
34 mg/L
EC10 or NOEC for freshwater algae:
19 mg/L

Additional information

Three reliable studies investigating toxic effects of C16-18AS Na (CAS 68955-20-4) to freshwater algae are available. The key non-GLP study was performed with Desmodesmus subspicatus according to DIN 38412 (9) (Richterich 2001). Growth inhibition caused by the test substance was determined after 24, 48 and 72 hours of exposure to eleven test concentrations up to 3000 mg/L substance of 55.5% purity (equal to 1650 mg a.i./L). No analytical monitoring is available. The results show that the 72-hour EC50 value for growth rate was 34 mg a.i./L and for biomass 30 mg a.i./L (nominal concentrations). The EC10 for biomass was 19 mg a.i./L (nominal concentrations). Moreover, the non-GLP study by Steber (1988) with Chlorella vulgaris performed according to Algal Assay Procedure Bottle Test, National Research Program, US EPA (1971) is available. Algae were exposed to the test substance for 14 days. The reported EC50 value for growth rate is 14.4 mg a.i./L and the EC10 value for growth rate is 28.6 mg/L (nominal concentrations, no analytical monitoring available). Another non-GLP test reported by Steber (1988) was done with Desmodesmus subspicatus according to the procedure for growth inhibition toxicity testing by UBA Berlin, 1984. Algae were exposed to the test substance for 96 hours. The EC50 value for growth rate was 57.6 mg a.i./L (nominal concentration, no analytical monitoring available). The EC10 value for growth rate was 25.5 mg a.i./L (nominal concentration).