Fatty acids, C16-18 and C18-unsatd., tetraesters with pentaerythritol

Toxicity to microorganisms

Description of key information

EL50 (16 h) > 10000 mg/L (ISO 10712)

Additional information

In accordance to Regulation (EC) No. 1907/2006 Annex XI, 1.5 a read across to two structurally related sub-category memberspentaerytritol tetraoleate (CAS 19321-40-5)and decanoic acid, mixed esters with heptanoic acid, octanoic acid, pentaerythritol and valeric acid (CAS No. 71010-76-9) was conducted to fulfill the data requirements according to Annex IX forfatty acids, C16-18 and C18-unsatd., tetraesters with pentaerythritol (CAS 68604-44-4) in regard to toxicity to microorganisms.This read-across is justified in detail in the overall summary (IUCLID chapter 6.1) and within the category 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 fatty acid chain length of C16 and C18 of the first read-across substances are identical to those of the target substance. The second read-across substance covers the other end of the sub-category with shorter fatty acid chain lengths (C5-10). All substances contain the same alcohol (pentaerythritol) and are tetra-esters. As it can be seen in the data matrix of the category justification in section 13 and the overall summary, all reliable data in the category support the hazard assessment of each category member by showing a consistent pattern of results.

The first study with the read-across substancepentaerytritol tetraoleate (CAS 19321-40-5)was conducted under static conditions according to ISO 10712 investigating aquatic microorganisms (Mead, 1997). In this GLP study an aqueous suspension of Pseudomonas putida was used as inoculum. A nominal test concentration of 10000 mg/L was used (prepared as WAF). The test substance did not inhibit the growth of Pseudomonas putida. Hence, the 16 h-EL50 was determined to be > 10000 mg/L based on the nominal test concentration. This result is confirmed by the result of the toxicity control of the biodegradation study with the read-across substance (Desmares-Koopmans, 1997). In this study according to OECD 301B a 14 d-NOEC of 15.6 mg/L could be determined, based on the inhibition control.

The second study with the read-across substance decanoic acid, mixed esters with heptanoic acid, octanoic acid, pentaerythritol and valeric acid (CAS No. 71010-76-9) supports this result. It was conducted under static conditions according to OECD 209 investigating aquatic microorganisms (Dickinson, 2008). In this GLP studynon-adapted activated sludge obtained from a domestic sewage treatment plant was used as inoculum. Test concentrations of 10, 100 and 1000 mg/L were prepared. Test substance was added directly to the test vessels. The test substance did not inhibit the respiration rate of activated sludge microorganisms at any of the concentrations employed in the test. Hence, the 3 h-EC50 was determined to be > 1000 mg/L based on the nominal test concentration. Therefore it can be concluded that the test substance will not exhibit effects on the respiration rate of microorganisms. Based on these results from 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, it can be concluded thatfatty acids, C16-18 and C18-unsatd., tetraesters with pentaerythritol (CAS 68604-44-4)will not exhibit inhibitory effects to aquatic microorganism.