N-butyl acetate

Toxicity to aquatic algae and cyanobacteria

Description of key information

The effect of n-butyl acetate on growth of Desmodesmus subspicatus (reported as Scenedesmus subspicatus) was investigated: 72-h NOEC: 200 mg/L, 72-h ErC50 = 648 mg/L  (no analytical monitoring; Huels, 1988).
In an OECD 201 study with the analogue substance iso-butyl acetate the following vaules were determined: 72-h NOEC: 196 mg/L, 72-h ErC50 = 397 mg/L  (CERI, 2000) (lowest values from three studies evaluated in a weight-of-evidence approach).

Key value for chemical safety assessment

EC50 for freshwater algae:

397 mg/L

EC10 or NOEC for freshwater algae:

196 mg/L

Additional information

The growth inhibiting effect of n-butyl acetate on algae was tested with Desmodesmus subspicatus (reported as Scenedesmus subspicatus). The exposure duration was 72 h. No analytical monitoring. The report does not present raw data. The reported effect values were: 72 -h NOEC: 200 mg/L, 72 -h EC10: 296 mg/L, 72 -h EC50: 648 mg/L and 72 -h EC90: 1541 mg/L.

In a further study with limited documentation growth inhibtion of n-butyl acetate on Scenedesmus sp. was tested over 96 h. An EC 3 of 320 mg/L was found in this study.

In a third study the inhibting effect of iso-butyl acetate (CAS 110 -19 -0) on growth rate of Pseudokirchnerella subcapitata (reported as Selenastrum capricornutum) was tested for 72 h. An EC50 of 397 mg/L and a NOAEC of 196 mg/L was determined in this reliable OECD 201 study. Justification of using these data for reading-across to the submission substance is provided in the documentation included in section 13.

In a weight-of-evidence evaluation these data show that toxicity of n-butyl acetate to algae is low and less compared to test organisms of other trophic levels. The lowest NOAEC observed comes from the study using iso-butyl acetate.