Fatty acids, C16-18 and C18-unsatd., Me esters, epoxidized

Bioaccumulation: aquatic / sediment

Description of key information

Significant accumulation of the test item in organisms is not to be expected.

Additional information

Estimations of the BCF were performed with two different models. The results are evaluated in a weight-of-evidence-approach:

- EPISuite v4.1/BCFBAFv3.01: A BCF value of 528.5 was estimated on the basis of the log Kow of 6.71. Using the Arnot-Gobas method including biotransformation rates the BCF for the upper trophic level was estimated at 136.5; the BAF for the upper trophic level was estimated at 151.9.

- A BCF calculation using the CATALOGIC v.5.11.9.8 BCF base-line model v.02.05 is available for Fatty acids, C16 -18 and C18 -unsatd., Me esters, epoxidized (CAS 158318-67-3). The influence of mitigating factors like ionization of the molecule, water solubility, size and metabolism are also considered by the model. Taking into account these mitigating factors the BCF is reduced to 43.04 (log BCF = 1.6339), mainly due to metabolism.

Besides metabolism also the low water solubility and the molecular size reduce the log BCF as estimated by the model. Both parameters are discussed within the literature whether certain threshold values are suitable as cut-off criteria for indication of limited bioaccumulation. Regarding molecular size, the PBT working group on hazardous substances discussed a maximum diameter of > 17.4 Å (Comber et al., 2006).

The maximum diameter average of the test item is determined to be 17.8887 Å, depending on its conformation. All in all, based on the predicted log BCF of 1.6339 significant bioaccumulation is not to be expected in animal tissues. The test substance is to 100% within the parameter ranges, and 90.91% within the structural domain of the model.

CONCLUSIONS:

Following the calculated log Kow value of 6.71 (uncharged molecule) bioccumulation in organisms may not be excluded.

In two separate estimation models (BCFBAF v3.01 and CATALOGIC v5.11.9.8 BCF base-line model v.02.05) the BCF were calculated.

Using the estimation model BCFBAF v.3.01, the BCF value of the test item is calculated with 136.5 (Arnot-Gobas-method, upper trophic level). Using Catalogic v 5.11.9.8 [BCF base-line model v02.05], and considering mitigating factors like biotranformation, water solubility and molecular size, the BCF value is reduced to 43.04 (log BCF 1.6339), indicating low potential for bioaccumulation. In addition, due to the low water solubility exposure of aquatic organisms to significant amounts is unlikely. Therefore, unacceptable risks due to possible bioaccumulation are not expected.

The substance has a log Kow value above 3, suggesting potential to bioaccumulate. Nevertheless, the information gathered on environmental behaviour and metabolism in combination with the QSAR-estimated BCF values provide enough evidence (in accordance to the REACh Regulation (EC) No. 1907/2006, Annex XI General rules for adaptation of the standard testing regime set out in Annexes VII to X, 1.2, to cover the data requirements of Regulation (EC) No. 1907/2006, Annex IX) to state that these substance is likely to show low bioaccumulation potential.