Registration Dossier

Environmental fate & pathways

Endpoint summary

Administrative data

Description of key information

Additional information

The assessment of biodegradation is based on 19 valid, reliable studies available within the category. In all of these studies the test substance was determined to be readily biodegradable. The study conducted with the read-across substance dodecanoic acid, isooctyl ester (CAS No. 84713-06-4) was not used for assessment, due to the low sludge concentration (1.6E03 cells/mL) in the test solution. Within this test, the substance almost fulfilled the criteria for ready biodegradation under the test conditions and would have probably passed if it had been tested with a higher, standard sludge concentration. Hence, the results of the biodegradation tests within the category are consistent, and the substances can be considered as readily biodegradable.

 

The 19 available studies cover the variability of the category with different alcohol and fatty acid chain lengths (MW 256.42 - 396.7 mg/L). The data gaps within the category can thus be filled by intrapolation. Only the smallest constituent of the UVCB isopentyl decanoate and octanoate (CAS No. 1365095-43-7) is outside the size range of the tested substances (MW 214.34 mg/L). However, the substance has practically the same structure as isopentyl laurate (CAS No. 6309-51-9), which was shown to be readily biodegradable, and having a shorter fatty acid chain, should be even more easily biodegraded (Bozcar et al., 2001).

 

In conclusion, the data available on biodegradation for the SCAE C2-C8 category show a clear, consistent pattern of ready biodegradability. SCAE C2-C8 is a robust category with a large amount of reliable, consistent data throughout the category. In each case of read-across, the best suited (highest degree of structural similarity, nearest physico-chemical properties) read-across substances were entered into IUCLID. Generally, larger and branched molecules are considered as a worst case approach, since the chain length and substitutions are determining factors for biodegradation of fatty acid alcohol esters (Boczar et al., 2001; Dias and Alexander, 1971). Furthermore, as can be seen in the data matrix of the category justification in Section 13, all reliable data in the category support the hazard assessment of each category member, by showing a consistent pattern of results.

 

Boczar, B.A., Forney, L., Begley, W., Larson, R.J. and Federle, T.W., 2001,Water Research Vol. 35, No. 17, pp. 4208–4216

Dias, F.F. and Alexander, M., 1971, Applied Microbiology, Vol. 22, No. 6, p. 1114-1118