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Ecotoxicological information

Toxicity to microorganisms

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Reference
Endpoint:
toxicity to microorganisms, other
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
key study
Justification for type of information:
Refer to analogue justification document provided in IUCLID section 13.
Reason / purpose:
read-across source
Duration:
14 d
Dose descriptor:
NOEC
Effect conc.:
>= 20 mg/L
Nominal / measured:
nominal
Conc. based on:
test mat.
Basis for effect:
other: Result of toxicity control from ready biodegradability test
Remarks on result:
other:
Remarks:
source, RA-A, CAS 68604-38-6, REAGENS, 2012, Toxicity Control of OECD 301 B, RL2

Description of key information

NOEC (14 d) ≥ 20 mg/L (Toxicity control of ready biodegradation test OECD 301B); read-across.

Key value for chemical safety assessment

Additional information

No study investigating the toxicity of Octadecanoic acid, ester with 2,2'-[oxybis(methylene)]bis[2- (hydroxymethyl)-1,3-propanediol] (CAS 70969-57-2) to aquatic microorganisms is available. Therefore, 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., hexaesters with dipentaerythritol (CAS 68604-38-6) is applied.

Based on the high degree of similarity between the structural and physico-chemical properties of the target and source substance, the source substance is considered a suitable representative for the evaluation of the toxicity of the target substance to aquatic microorganisms. The read-across approach is justified in detail within the analogue justification in IUCLID section 13.

Since no studies on the toxicity to activated sludge microorganisms are available a toxicity control from a ready biodegradability study of Fatty acids, C16-18 and C18-unsatd., hexaesters with dipentaerythritol (CAS 68604-38-6) is used to derive a NOEC for the toxicity to activated sludge microorganisms. If a compound degrades well in a ready biodegradability test, or does not inhibit the degradation of a positive control at a certain concentration, this concentration can be used as a NOEC value. This approach is in accordance with the Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, ECHA 2017).

A substance can be assumed to be not inhibitory to activated sludge microorganisms, if in the toxicity control of a ready biodegradation test, more than 25% degradation based on CO2 evolution (CO2/ThCO2) occurred within 14 days (OECD guideline 301). For Fatty acids, C16-18 and C18-unsatd., hexaesters with dipentaerythritol (CAS 68604-38-6) a biodegradation test according to OECD guideline 301B is available. The test includes a toxicity control, which contains 20 mg/L of the test substance and 20 mg/L of the reference material (sodium benzoate). The toxicity control attained 26.7% degradation after 5 days of incubation (40.9% after 14 d). Hence, the substance is not toxic to aquatic microorganisms in the toxicity control and a NOEC (14 d) ≥ 20 mg/L was derived.

Based on the available results from structurally related source 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 Octadecanoic acid, ester with 2,2'-[oxybis(methylene)]bis[2- (hydroxymethyl)-1,3-propanediol] (CAS 70969-57-2) will not exhibit effects to microorganisms up to the limit of water solubility.