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Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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Description of key information

The analogue substance is not bioaccumulative.

Key value for chemical safety assessment

BCF (aquatic species):
77.7 L/kg ww

Additional information

In accordance with column 2 of EC 1907/2006 Annex IX bioaccumulation testing in aquatic species is not required if the substance has a low potential for bioaccumulation. Due to the chemical properties of the test substance the potential for bioaccumulation is assumed to be low.

There is no specific data on the substance. Read-across to the properties of Hexanoic acid, 3,5,5-trimethyl-, 1,1'-[2-ethyl-2-[[(3,5,5-trimethyl-1-oxohexyl)oxy]methyl]-1,3-propanediyl] ester (EC 613-848-7, CAS65870-94-2),Fatty acid polyols (Fatty acids, C5-9, esters with pentaerythritol (EC 270-290-3, CAS 68424-30-6) and Decanoic acid, ester with 2-ethyl-2-(hydroxymethyl)-1,3-propanediol octanoate (EC 234-392-1, CAS 11138-60-6)) and their analogues is applicable based on the similarity in structure and physico-chemical properties.

The justification for read-across is presented in Section 13 Assessment reports- Read-across justification.

The log Kow for EC 613-848-7 was experimentally determined to be > 9.4 . For log Kow values between 1 and 6, the BCF increases linearly. At very high log Kow (> 6), a decreasing relationship between the two parameters is observed. Moreover, the experimental and QSAR-based determination of the BCF is inaccurate or even technically not feasible for poorly water soluble substances like EC 613-848-7. For substances with a log Kow of > 10 the BCF is probably lower than 2000 L/kg which indicates that the test substance is not bioaccumulative according to the PBT-criteria (according to “Guidance on information requirements and chemical safety assessment – Chapter R.11: PBT Assessment” published by ECHA (2008)). A BCF was calculated to be 77.7 L/kg wet weight (BCFBAF v3.00, regression based estimate) which correlates with the assumptions from the ECHA Guidance.

Furthermore, a log Kow of ≥ 10 can be taken as an indicator for reduced bioaccumulation potential (according to “Guidance on information requirements and chemical safety assessment – Chapter R.7c: Endpoint specific guidance” published by ECHA (2008). As the Log Kow of the test substance has been experimentally determined to be > 9.4 the substance is not expected to be bioaccumulative.

In addition, the test substance is poorly soluble in water (< 2.4 mg/L) so only low concentrations can be expected in the aquatic environment and thus in aquatic organisms. Furthermore the test substance is readily biodegradable. If the test substance is occasionally released to the aquatic environment it will be readily biodegraded, which reduces the potential uptake by aquatic organisms.

Acute studies with aquatic organisms on structural analogue substances did not result in any toxic effects in the range of water solubility.

The justification for read-across is presented in Section 13 Assessment reports- Read-across justification.

Chronic toxicity data with mammals exhibited no toxic effects to rats after 28- days of exposure for the read-across substance Fatty acids, C5-10, esters with pentaerythritol (CAS 68424-31-7). This is an indication that the test substance is chronically non-toxic.

Although there are no quantitative data on the uptake of Fatty Acid Polyol Esters they might be absorbed via oral, respiratory, and dermal routes of exposure. The absorbability of esterified alcohols containing one to eight ester groups given orally has been studied and there was little difference for polyol esters up to four ester groups. Esters of polyols (pentaerythritol, dipentaerythritol and 1,1,1-trimethylolpropane) have a common metabolic fate that involves stepwise hydrolysis to the carboxylic (e.g. fatty) acids and their polyols (pentaerythritol, dipentaerythritol or trimethylolpropane), respectively. This is supported by the action of ubiquitously distributed unspecific esterases and by site-specific and non-specific gastrointestinal lipases so only low and transient exposure to the parent compound is expected.

Straight-chain fatty acids are normal dietary constituents and ubiquitous substrates for energy production by physiological pathways like the citric acid cycle, sugar synthesis, and lipid synthesis. Medium-chain fatty acids (MCFA) are readily absorbed from the small intestine directly into the bloodstream and transported to the liver for hepatic metabolism, while long-chain fatty acids (LCFA) are less readily absorbed, are incorporated into chylomicrons and enter the lymphatic system. It has been noted by several investigators that increasing fatty acid chain length slightly decreased their digestibility. MCFA are readily broken down to carbon dioxide and two-carbon fragments, while LCFA are re-esterified to triacylglycerols and either metabolized for energy or stored in adipose tissue. Fatty acids are therefore inherently harmless.

The polyols are very polar (log Kow<-2) and do not accumulate in the body but are readily excreted via urine. Alternatively, one or several hydroxyl groups can be oxidized to a carboxylic acid moiety prior to urinary excretion. In conclusion there are sufficient toxicity data for both the resulting fatty acids and the alcohol component, showing that the metabolites have little or no potential to cause toxic effects.

Thus, in view of the harmlessness of degradation products and that no bioaccumulation in animal tissue is expected, further testing is not necessary.

Therefore, in accordance with Annex XIII the substance is not bioaccumulative.