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Toxicity to aquatic algae and cyanobacteria

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Description of key information

Scenedesmus subspicatus: 72-h ErC50 = 20 mg/L; 72-h ErC10 = 3.3 mg/L (mean measured; BASF, 1989)

Key value for chemical safety assessment

EC50 for freshwater algae:
20 mg/L
EC10 or NOEC for freshwater algae:
3.3 mg/L

Additional information

The growth inhibiting effect of valeraldehyde on algae was tested with Scenedesmus subspicatus according to EC Directive 79/831 EEC, Annex V, Section C. The reported effect values for growth rate are: 72 -h ErC50 = 20 mg/L, 72-h ErC10 = 3.3 mg/L (mean measured; BASF, 1989).

The growth inhibiting effect of valeraldehyde on algae was tested with Pseudokirchneriella subcapitata according to OECD 201. The initial cell density of 1E04 cells/mL. The exposure duration was 96 h. The test item concentrations were analytically verified. Results from the day 0 analysis yielded 93.4 to 120% of target values for the bulk dose solutions. The day 4 test solutions (with or without algae) yielded no quantifiable concentrations of n-valderaldehyde. Therefore the mean measured concentrations were used to express the effect values.

The reported effect values for growth rate are: 72 -h NOEC = 1.43 mg/L, 72 -h ErC50 = 123 mg/L (Dow, 2003).

Data from the NITE database state lower effect values for growth rate (72-h EC50 > 9.3 mg/L; NOEC = 4.1 mg/L; NITE 2010). Due to the better reliability and documentation the results from Dow (2003) were used for the evaluation of the toxic effects on algal growth.