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Ecotoxicological information

Short-term toxicity to fish

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Description of key information

No effects on fish up to the limit of water solubility

Key value for chemical safety assessment

Additional information

Studies are available for the pure homologue members of the fatty acid category. In addition some studies are summarized 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 fatty acids, hydrogenated tallow, distn. residues (CAS 700 -84 -4), which contains as main constituents C16 with a content of 5 - 35% and C18 with a content of 25 - 65%, read-across is performed to studies available for the pure homologues palmitic acid (C16 - CAS 57 -10 -3) and stearic acid (C18 - CAS 57 -11 -4). For evaluation of the mixture, only studies available for the pure homologues which were determined as key studies or used of a weight of evidence approach were chosen for a read-across. All linked studies conducted with the pure homologues were used in a weight of evidence approach to cover the endpoint "short-term toxicity to fish" for the considered fatty acid mixture.

 

Fatty acid homologue

LC50
(as reported in the study)

Water solubility*

Test design and species

Reference

C16 - CAS 57-10-3
palmit
ic acid

> 1000 mg/L (nominal)

< 0.05 at 20 °C

96 h, semi-static,
Danio rerio

Richterich and Mühlberg, 2001b

C18 - CAS 57-11-4
stearic acid

> 10000 mg/L (nominal)

insoluble

48 h, static,
Leuciscus idus

Richterich and Mühlberg, 2001c

* see category justification

The homologue C16 (palmitic acid: CAS 5 7 -10 -3) was tested on zebrafish (Danio rerio) according to ISO 7346 -1 in a semi-static test (Richterich and Mühlberg, 2001b). In the study nominal concentrations of 0.1, 0.5, 2.8, 16, 90, 250 and 1000 mg/L were tested. No mortality was observed at any test concentration and thus up to the limit of water solubility which is below 0.05 mg/L. In the study the LC50 was reported to be above 1000 mg/L.

The homologue C18 (stearic acid: CAS 57 -11 -4) was tested on golden orfe (Leuciscus idus) (Richterich and Mühlberg, 2001c). In the static test, which was conducted according to DIN 38412/15, the fish were exposed to different concentrations of the test substance (1000, 3000, 10000 mg/L nominal). In the study no effects on fish were reported, resulting in a LC50 > 10000 mg/L.

Concluding from the results reported for the pure homologues C16 and C18 no toxicity within the range of water solubility is expected for the considered fatty acid mixture.