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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

EL50 (16 h) > 10000 mg/L for Pseudomonas putida (ISO 10712).
NOEC (3 h) 1000 mg/L for activated sludge microorganisms (OECD 209).

Key value for chemical safety assessment

Additional information

Since no experimental studies investigating the toxicity of fatty acids, tall-oil, triesters with trimethylolpropane (CAS 94581-09-6) to activated sludge microorganisms are available for this endpoint, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5 a read across to the structurally related source substances fatty acids, C16-18 (even numbered) and C18-unsatd., branched and linear, di- and triesters with trimethylolpropane (former CAS 85005-23-8), fatty acids, C16-18 and C18-unsatd., branched and linear ester with trimethylolpropane (CAS 403507-18-6) and fatty acids, tall-oil, triesters with trimethylolpropane was conducted. The latter substance is not the same as the substance subject to registration since it contains of modified tall-oil fatty acids. This read-across is justified in detail in the overall summary (IUCLID section 6.1) and within the analogue justification in IUCLID Section 13. In this case of read-across, the best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substances were used for the assessment.

The first study with the read-across substance fatty acids, C16-18 (even numbered) and C18-unsatd., branched and linear, di- and triesters with trimethylolpropane (former CAS 85005-23-8) was performed according to ISO 10712 with Pseudomonas putida (Pateman, 1997). No effect on the growth of Pseudomonas putida was observed at the tested concentration of 10000 mg/L and an EL10 and EL50 (16 h) > 10000 mg/L (WAF loading rate) was derived. Furthermore, the biodegradation tests exhibit the readily biodegradability of the test substance.

The second study with the read-across substance fatty acids, C16-18 and C18-unsatd., branched and linear ester with trimethylolpropane (CAS 403507-18-6) was performed according to OECD 209 (GLP) using activated sludge microorganisms (Clarke, 2004). A limit test concentration of nominal 1000 mg/L was used. Activated sludge from the aeration stage of a municipal sewage treatment plant was collected as inoculum. Oily globules of test material were visible on the surface and dispersed throughout the test media at 0 h, 30 min and 3 h contact time. However, no effects on the respiration rate was observed after 3 h resulting in an EC50 (3 h) of > 1000 mg/L and a NOEC (3 h) of 1000 mg/L.

The third substance fatty acids, tall-oil, triesters with trimethylolpropane containing modified tall-oil fatty acids was performed according to OECD 209 with activated sludge from a communal sewage treatment plant. After 3 h no inhibition of respiration was observed resulting in an EC10/50 > 10000 mg/L.

Based on the available experimental studies from three structurally related read-across substances (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which are characterized by a similar ecotoxicological profile and comparable structure, it can be concluded that fatty acids, tall-oil, triesters with trimethylolpropane (CAS 94581-09-6) will not exhibit effects to activated sludge microorganisms.