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Toxicity to microorganisms

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Description of key information

NOELR (16 h) >= 10000 mg/L (ISO 10712; Pseudomonas putida); read-across

Key value for chemical safety assessment

Additional information

No studies investigating the toxicity to microorganisms of Fatty acids, C18 unsaturated, trimers, hydrogenated are available. Therefore, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5, a read across to the structurally similar substances Fatty acids, C18-unsatd., dimers (CAS No. 61788-89-4), Fatty acids, C16-18 and C18-unsatd., branched and linear (CAS No. 68955-98-6) and Isooctadecanoic acid (CAS No. 30399-84-9). Further justification is given within the endpoint summary 6.1 and within the analogue justification in Section 13.

The key study conducted with Fatty acids, C18-unsatd., dimers (CAS No. 61788-89-4) was performed as a limit test following a guideline similar to ISO 10712 and according to GLP (Sewell, 1997). The test organism Pseudomonas putida was exposed to the test substance at a loading rate of 10000 mg/L, prepared as water accommodated fractions (WAF), for 16 hours. As no significant growth inhibition was observed, the NOELR was reported to be ≥ 10000 mg/L.

The key study conducted with Fatty acids, C16-18 and C18-unsatd., branched and linear (CAS No. 68955-98-6) was performed as a limit test according to ISO 10712 and GLP (Mead, 1997). The test organism Pseudomonas putida was exposed to the test substance at a loading rate of 1000 mg/L, prepared as water accommodated fractions (WAF), for 16 hours. As no significant growth inhibition was observed, the NOELR was reported to be ≥ 10000 mg/L.

The key study conducted with Isooctadecanoic acid (CAS No. 30399-84-9) was performed as a limit test according to the Guideline Bewertung Wassergefährdender Stoffe (1979). The effect of the test substance on cell multiplication of a pure culture of Pseudomonas putida was assessed. Cultures of the bacteria were exposed to concentrations ranging from 0.001 to 4.8 mg/L and to an oversaturated concentration of test substance. As no significant growth inhibition was observed, the NOEC was reported to be ≥ 4.8 mg/L.

Thus, based on the above mentioned results, and due to the structural and profile similarities of the substances, as are explained with in the overall endpoint summary 6.1 it can be concluded that no significant toxicological effects on microorganisms are expected for Fatty acids, C18 unsaturated, trimers, hydrogenated.