Registration Dossier

Administrative data

Link to relevant study record(s)

Description of key information

Key value for chemical safety assessment

Additional information

No experimental data evaluating the toxicity to sediment organisms is available 2,2-bis[[(1-oxoisononyl)oxy]methyl]-1,3-propanediyl diisononanoate(93803-89-5).The substance is not toxic to aquatic organisms up to the limit of water solubility and in addition, available data indicate that 2,2-bis[[(1-oxoisononyl)oxy]methyl]-1,3-propanediyl diisononanoateis not bioaccumulative. Based on the available information, toxicity to sediment organisms is not expected to be of concern.

Intrinsic properties, fate and bioaccumulation

2,2-bis[[(1-oxoisononyl)oxy]methyl]-1,3-propanediyl diisononanoateexhibits a log Koc value of > 5 and is poorly water soluble (< 0.05 mg/L measured in aqua dest). The Guidance on information requirements and chemical safety assessment, Chapter R7.b (ECHA, 2012) states that once insoluble chemicals enter a standard STP, they will be extensively removed in the primary settling tank and fat trap and thus, only limited amounts will get in contact with activated sludge organisms. Nevertheless, once this contact takes place, these substances are expected to be removed from the water column to a significant degree by adsorption to sewage sludge (Guidance on information requirements and chemical safety assessment, Chapter R.7a, (ECHA, 2012). Thus, discharged concentrations of this substance (if at all) into the aqueous/sediment compartment are likely to be low.

Bioaccumulation is not expected based on the molecular weight (697.04 g/mol), size and structural complexity of the substance the uptake from medium into sediment organisms is considered to be low (Dimitrov et al. (2002).

The supporting BCF/BAF values estimated with the BCFBAF v3.01 program, Arnot-Gobas model including biotransformation, also indicate that this substance will not be bioaccumulative (BCF and BAF values were calculated to be 0.893, respectively).

Considering this, one can assume that the availability of 2,2-bis[[(1-oxoisononyl)oxy]methyl]-1,3-propanediyl diisononanoatein the sediment environment is generally low, which reduces the probability of chronic exposure of sediment organisms in general.

Aquatic ecotoxicity data

Aquatic toxicity tests of the substance to fish, invertebrates, algae and microorganisms showed no adverse effects in the range of the water solubility (< 0.05 mg/L measured in aqua dest). The obtained results indicate that 2,2-bis[[(1-oxoisononyl)oxy]methyl]-1,3-propanediyl diisononanoateis likely to show no toxicity to sediment organisms as well.

Conclusion

Due to its log Koc value of > 5, significant adsorption of this substance to activated sludge in conventional STPs will take place and only low concentrations are expected to be released (if at all) into the environment. Once present in the aquatic compartment, due to the high log Kow, low water solubility and high adsorption potential, 2,2-bis[[(1-oxoisononyl)oxy]methyl]-1,3-propanediyl diisononanoatewill be bioavailable to sediment organisms mainly via feed and contact with suspended organic particles. However, based on the molecular weight, size and structural complexity of the substance the uptake from medium into sediment organisms is considered to be low. This is supported by a calculated BCF value below 2000 L/kg. Furthermore, aquatic toxicity data show that no effects occur up to the limit of water solubility. Therefore2,2-bis[[(1-oxoisononyl)oxy]methyl]-1,3-propanediyl diisononanoateis unlikely to pose a risk for sediment organisms in general and testing is thus omitted.

A detailed reference list is provided in the technical dossier (see IUCLID, section 13) and within the CSR.