Dipentaerythritol hexaesters of 3,5,5-trimethylhexanoic, n-decanoic, n-heptanoic, and n-octanoic acids

Long-term toxicity to fish

Additional information

The hazard assessment is based on the data currently available. New studies with the registered substance and/or other member substances of the polyol esters family will be conducted in the future. The finalised studies will be included in the technical dossier as soon as they become available, and the hazard assessment will be re-evaluated accordingly.

Experimental data on the long-term toxicity of fatty acids C5-10 esters with dipentaerythritol (CAS 70983-72-1) to fish are not available.

The release of the substance to the environment after passing through conventional Sewage Treatment Plants (STPs) is expected to be low. The Guidance on information requirements and chemical safety assessment, Chapter R7.b (ECHA, 2017) 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, 2017). Thus, discharged concentrations of this substance into the aqueous/sediment compartment are likely to be low. Furthermore, the available acute fish tests showed no adverse effects up to the limit of its water solubility (LL50/LC50 (96 h) > 100 mg/L (nominal), read-across substances). Based on the available information fish cannot be identified as the most sensitive organism. According to the Guidance on information requirements and chemical safety assessment, Chapter R7.b (ECHA, 2017), long-term toxicity testing on fish should only be conducted if it represents the most sensitive taxonomic group. The Guidance states that if invertebrates are likely to be more sensitive than fish and algae or the relative sensitivity of invertebrates cannot be predicted, long-term testing on Daphnia sp. should be preferred instead of fish. Long-term toxicity testing to aquatic invertebrates is available resulting in significant effects on reproduction at nominal concentrations of 2 mg/L (main test) and 100 mg/L (preliminary test).

Furthermore, the main components of the UVCB substance have high molecular weights of 759 to 1179.77 g/mol. Thus, it is unlikely that they are readily absorbed due to the steric hindrance of crossing biological membranes. Following the ‘rule of 5’ (Lipinski et al., 2001), developed to identify drug candidates with poor oral absorption, the substance is considered to be poorly absorbed after oral uptake based on criteria like partition coefficient (log Kow > 5) and molecular weight (> 500 g/mol).

 

In conclusion, long-term effects of Fatty acids C5-10 esters with dipentaerythritol on fish are not to be expected.

 

References

ECHA. 2017. Guidance on information requirements and chemical safety assessment – Chapter R.11: PBT assessment. European Chemicals Agency, Helsinki

Lipinski CA, Lombardo F, Dominy BW, Feeney PJ. 2001. Experimental and computational approaches to estimate solubility and permeability in drug discovery and development settings. Adv Drug Del Rev 46: 3–26