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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

No effect up to the limit of the water solubility of the test substance was observed.

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Additional information

One study, investigating the term toxicity to microorganisms of Fatty acids, C16-18 and C18-unsaturated, branched and linear (CAS No. 68955-98-6) is available. This study investigated the toxicity of the test substance to microorganisms is a cell multiplication inhibition test with Pseudomonas putida according to ISO 10712. Due to the low water solubility of the test substance, the test solutions were prepared as Water Accommodated Fractions (WAF). Within the 16 hours test period, while being exposed to a 10000 mg/L Water Accommodated Fraction loading rate, no effects on the growth rate of Pseudomonas putida up to the limit of the water solubility of the test substance were observed (Mead, 1997).

This test is supported by the findings of a similar test with a further dimerised fatty acids and its derivatives sub-category 1 member, Isooctadecanoic acid, investigating the toxicity to Pseudomonas putida.. The cultures of the bacteria were exposed to concentrations ranging from 0.001 to 4.8 mg/L (oversaturated concentration of test substance) for 18 hours. After 18h no effect on the growth inhibition of Pseudomonas putida was observed (Coenen, 1988). The water solubilities of the two substances vary. Isooctadecanoic acid has a water solubility < 1 mg/L. Fatty acids, C16-18 and C18-unsaturated, branched and linear has water solubility total sum of all components to be 15 mg/L, nevertheless it is expected that each component within the UVCB has solubility < 1mg/L. Hence it is important to note that both chemicals were observed to have a similar trend in their eco-toxicological profile - demonstrating that no toxicological can be expected tu to the water solubility limit.

Thus, it can be concluded that no toxicological effects on microorganisms are expected up to the water solubility of Fatty acids, C16-18 and C18-unsaturated, branched and linear (15 mg/L).