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Ecotoxicological information

Toxicity to microorganisms

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Description of key information

NOEC (3 h): ≥ 1000 mg/L for the respiration of activated sludge microorganisms (OECD 209); read-across

Key value for chemical safety assessment

Additional information

Only a short abstract is available on the toxicity of 2,2-dimethyl-1,3-propanediyl dioctanoate (CAS No. 31335-74-7) to microorganisms. The assessment of toxicity to microorganisms was, therefore, based on a study conducted with the structurally similar category member Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS No. 68855-18-5). This read across approach is in accordance with Regulation (EC) No 1907/2006, Annex XI, 1.5. Grouping of substance and read across approach. Further justification is given within the endpoint summary 6.1 and within the category justification in Section 13.

The key study conducted with Heptanoic acid, ester with 2,2-dimethyl-1,3-propanediol (CAS No. 68855-18-5) was performed according to OECD Guideline 209 and GLP (Roulstone, 2012). Activated sludge of a predominantly domestic sewage was exposed to the test substance during 3 hours, at nominal concentrations of 0, 10, 100 and 1000 mg/L. No effect on the respiration of activated sludge was observed, and the NOEC was reported to be ≥ 1000 mg/L.

The supporting study carried out with 2,2-dimethyl-1,3-propanediyl dioctanoate (CAS No. 31335-74-7) was conducted according to OECD Guideline 209 (Latham, 1996). Activated sludge was exposed to the test substance at the nominal test concentrations of 1, 3.2, 10, 32 and 100 mg/L. Significant inhibition was only observed at 10 mg/L. Since no significant inhibition occurred at the higher concentrations, the result at 10 mg/L was considered anomalous. The 3 hour EC10 was reported to be > 100 mg/L.

Thus, based on the above mentioned result, and due to the structural and profile similarities of the two substances, as are explained with in the overall endpoint summary 6.1 it can be concluded that no effects on microorganisms are expected up to the limit of water solubility for 2,2-dimethyl-1,3-propanediyl dioctanoate.