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Environmental fate & pathways

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DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5) is hydrolytically stable and therefore abiotic hydrolysis is not a relevant pathway in water. The substance is not readily biodegradable and based on an enhanced OECD 301B test, assessed as very persistent (vP). The substance has a log Koc > 5 indicating a potential to adsorb to soil and sediment particles. The estimated half time for the reaction with OH-radicals is < 7 hours (24h day; OH-concentration: 0.5E+06 OH/cm3). However, photodegradation is not an important environmental fate process since the substance is not expected to evaporate into the atmosphere due to its very low vapor pressure of < 0.01 Pa at 20 °C. Due to its low water solubility (< 0.05 mg/L in aqua bidest), and high potential for adsorption to soil and sediment particles, only low concentrations of the substance is expected to be released into the aquatic environment. The substance will be bioavailable to aquatic organisms mainly via feed and contact with suspended organic particles.

DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5) is not bioaccumulative, based on the criteria given in Regulation (EC) No. 1907/2006, Annex XIII, 1.1.2 (BCF < 2000 L/kg). After uptake by organisms, biotransformation of the substance by carboxylesterases into 2-Ethylhexanoic acid, Isononanoic acid and the corresponding alcohols 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. BCF/BAF values estimated with the BCFBAF v3.01 program, Arnot-Gobas model including biotransformation; support the assumption that this substance will not be bioaccumulative.

In conclusion, DiPE triisononanoate triethylhexanoate (CAS No. 68443-84-5) is found to be persistent in the environment. Due the low water solubility and high adsorption potential, the main route of exposure for aquatic organisms such as fish will be via food ingestion or contact with suspended solids. Ingested amounts of the substance in organisms are expected to be metabolized to 2-Ethylhexanoic acid, Isononanoic acid and Dipentaerythritol. 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).