Registration Dossier

Diss Factsheets

Ecotoxicological information

Sediment toxicity

Currently viewing:

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 DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5). The substance is not toxic to aquatic organisms up to the limit of water solubility and in addition, available data indicate that DiPE triisononanoate triethylhexanoate is not bioaccumulative. Based on the available information, toxicity to sediment organisms is not expected to be of concern.

Intrinsic properties and fate

DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5) exhibits a log Koc value of > 10 and is poorly water soluble (< 0.05 mg/L measured in aqua dest).The Guidance on information requirements and chemical safety assessment, Chapter R.7b (ECHA, 2012b) 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, 2012a)). Thus, discharged concentrations of these substances into the aqueous/sediment compartment are likely to be low.

Considering this one can assume that the availability of DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5) in the sediment environment is generally low, which reduces the probability of chronic exposure of sediment organisms in general.

Aquatic ecotoxicity data

Acute and chronic aquatic toxicity tests of the substance and its read across substances (CAS No. 647028-25-9, Dipentaerythritol ester of nC5/iC9 acids; CAS No. 84418-63-3, Isononanoic acid, mixed esters with dipentaerythritol, heptanoic acid and pentaerythritol) to fish, invertebrates, algae and microorganisms showed no adverse effects occurred in the range of the water solubility of the substance (< 0.05 mg/L measured in aqua dest). The obtained results indicate DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5) is likely to show no toxicity to sediment organisms as well.

Metabolisms/Bioaccumulation

After uptake by organisms, biotransformation of the substance by carboxylesterases into 2-Ethylhexanoic acid, Isononanoic acid and the corresponding alcohol is expected. However, the molecular weight range of 1053 g/mol and the high octanol/water partition coefficient of > 10 in combination with the low water solubility, indicates a low absorption and correspondently slower hydrolysis rate for this substance. All three metabolites are not of concern for the environment. REACh registration dossiers of 2-Ethylhexanoic acid, Isononanoic acid and Dipentaerythritol are available and can be publicly viewed on the ECHA webpage (http://echa.europa.eu/web/guest/information-on-chemicals/registered-substances). QSAR estimations using BCFBAF v3.0 support the expected low bioconcentration with BCF/BAF values of <1 L/kg for this substance.

Conclusion

Due to its log Koc value of > 10, 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, DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5) will be bioavailable to sediment organisms mainly via feed and contact with suspended organic particles. After uptake by sediment species, biotransformation of the substance by carboxylesterases into 2-Ethylhexanoic acid, Isononanoic acid and the corresponding alcohol is expected. 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 (all below 1 L/kg). Furthermore, aquatic toxicity data show that no effects occur up to the limit of water solubility. Therefore, DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5) is 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 CSR.