Registration Dossier

Diss Factsheets

Ecotoxicological information

Toxicity to microorganisms

Currently viewing:

Administrative data

Link to relevant study record(s)

Description of key information

NOEC (14 d) ≥ 26.7 mg/L (Toxicity control OECD 301B)

Key value for chemical safety assessment

Additional information

Since no studies investigating the toxicity of 2,2-bis(hydroxymethyl)propane-1,3-diyl didocosanoate (CAS 68258-72-0) to activated sludge microorganisms are available, in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5 a read-across to the structurally related source substance Fatty acids, C16-18 and C18-unsatd., esters with pentaerythritol (CAS 85711-45-1) was conducted. The source substance is representative to evaluate the short-term toxicity of the target substance to aquatic algae.

The target substance 2,2-bis(hydroxymethyl)propane-1,3-diyl didocosanoate (CAS 68258-72-0) is characterized di-, tri-, tetraester of pentaerythritol an fatty acids with a chain lengths of C22. The degree of esterification is variable. However, mainly tri- and tetraesters are the result of the esterification process. Source substance Fatty acids, C16-18 and C18-unsatd., esters with pentaerythritol is characterised as a mono-, di-, tri- and tetraester of pentaerythritol with mainly C18 unsaturated 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 substance was used for the assessment.

One study investigating the toxicity of the source substance fatty acids, C16-18 and C18-unsaturated, esters with pentaerythritol (CAS 85711-45-1) to activated sludge microorganisms is available. An inhibition control of a ready biodegradability study using activated sludge as inoculum was used for the assessment (Muckle, 2013). In this study according to OECD 301B a NOEC (14 d) of ≥ 26.7 mg/L could be determined indicating no inhibition of respiration. In accordance with the OECD Guideline 301 the test substance can be considered to be not inhibitory to the inoculum if in a toxicity test, containing both the test substance and a reference compound, more than 25% degradation (based on total ThOD or ThCO2) occurred within 14 d. It can therefore be concluded that the source substance fatty acids, C16-18 and C18-unsaturated, esters with pentaerythritol (CAS 85711-45-1) will not exhibit inhibitory effects to aquatic microorganisms. The test item concentration in the toxicity control of 26.7 mg/L can be used as NOEC value for the toxicity to activated sludge microorganisms.

In addition to this result a qualitative assessment of the toxicity to activated sludge microorganisms can be made based on the biodegradation study conducted with the target substance itself. Due to a technical error the toxicity control could not be evaluated in the available study on the ready biodegradability of the target substance (Simon, 2016). However, according to the laboratory there is no plausible hint for toxicity on sewage sludge organisms by the test item. Biodegradation was observed the test suspensions and in the toxicity control assays - even though no quantification is possible in the latter ones. Thus, the test item 2,2-bis(hydroxymethyl)propane-1,3-diyl didocosanoate can be expected to be non-toxic to activated sludge microorganisms in a ready biodegradability test.

Based on the available result from a structurally related source substance (in accordance to Regulation (EC) No 1907/2006 Annex XI, 1.5) which is characterized by a similar ecotoxicological profile and comparable structure and the study for the target substance itself, it can be concluded that 2,2-bis(hydroxymethyl)propane-1,3-diyl didocosanoate will not exhibit detrimental effects on activated sludge microorganisms.