Fatty acids, dehydrated castor-oil

Endpoint summary

Additional information

The biodegradation data for the members of the fatty acids category includes standard biodegradation studies as well as modelling data (QSAR). The vast majority of the experimental results revealed ready biodegradability which was supported by reliable QSAR predictions. As summarized in the category justification, the members of the fatty acids will predominantly ready biodegrade. Individual degradation rates reported may vary to some degree depending on their physico chemical properties (e.g. water solubility), bioavailability and test methods employed. In some cases insufficient sampling points were available to determine whether or not the 10-day window was met. Studies in which the 10-day window was not met likely did not ensure that the fatty acids tested were fully in solution. According to the ECHAs Guidance on information requirements and chemical safety assessment (Chapter R.7b: Endpoint specific guidance, 2008) the screening tests on ready biodegradation sometimes fail because of the stringent test conditions, in general, and the differences among the individual tests in terms of their stringency. Therefore, consistent positive test results should generally supersede negative results. In conclusion, aliphatic fatty acids comprising C6-C22 carbon chain length are readily biodegradable providing a sufficient bioavailability is given. This judgment is consistent with the hazard assessment presented in the OECD SIDS (2009) for the category “Aliphatic Acids Category” where aliphatic fatty acids with a carbon chain length in the range of C6 – C22 also were judged to be readily biodegradable.