Registration Dossier

Ecotoxicological information

Toxicity to aquatic algae and cyanobacteria

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

No effects up to the limit of water solubility are expected.

Key value for chemical safety assessment

Additional information

Studies are available for some pure homologue members of the fatty acid category. In addition some studies are available for certain fatty acid mixtures. Generally it could be stated that toxicity of fatty acids to aquatic organisms increases with increasing chain length up to the water solubility limit at a chain length of C12. For longer chains no effects at saturation are observed.

For the mixture under discussion here no study on algae is available. Thus a read-across is prepared to a study conducted with the pure homologue C16 (CAS 57 -10 -3), one of the main components of the mixture. For the other main constituent, stearic acid, no test on algae is available.

For the evaluation of the mixture only studies available for pure homologues which were determined as key were chosen for read-across.

Fatty acid homologue

EC50for growth rate (as reported in the study)

Water solubility*

Test design and species

Reference

C16 - CAS 57-10-3 palmitic acid

> 0.9 mg/L (initial mean measured)

< 0.05 at 20 °C

72 h, static,
Pseudokirchneriella subcapitata

NITE, 2003b

* see category justification

Palmitic acid (C16: CAS 57 -10 -3) was tested on Pseudokirchneriella subcapitata as well under OECD 201 in a GLP-study (NITE, 2003b). One test substance concentration was used (10 mg/L nominal, corresponding to 0.9 mg/L initial mean measured), which was above the reported water solubility limit for this substance (< 0.05 mg/L according to the category justification). As no effects could be observed at this test concentration, the EC50 for growth rate is reported to be above 0.9 mg/L (initial mean measured).

From the reported results of the test available for the fatty acid homologue C16 no adverse effects of the considered fatty acid mixture are expected on algae. In the cited test no effects up to the water solubility limits of the pure homologues were reported. Thus for the considered fatty acid mixture no effects within the range of water solubility is expected.