Registration Dossier

Environmental fate & pathways

Bioaccumulation: aquatic / sediment

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The assessment entity “tall oil” is a mixture of different saturated and unsaturated C16 -C18 fatty acids. Therefore, the endpoint is addressed with publicly available data on fatty acids with the same or similar structure, including conservatively fatty acids with a shorter chain (i.e. C14) if relevant and appropriate in accordance with previously applied read-across approaches (U.S. EPA Fact Sheet, 2008).

A registration dossier shall contain information on the environmental hazard assessment (Regulation 1907/2006, Article 10). For the environmental hazard assessment of tall oil, the standard testing regime set out in Annexes VII to IX is adapted in accordance with Section 1.2 and 1.3 of Annex XI so that “testing does not appear to be scientifically necessary” as follows:

(I) The ecotoxic potential of the fatty acid (tall oil) is assumed to be negligible. Fatty acids are generally not considered to represent a risk to the environment, which is reflected in their exemption from the obligation to register (Annex V, Section 9 and Regulation (EC) No 987/2008).

(II) Based on reviews of HERA (2003) and OECD SIDS (2014), the water solubility of fatty acids seems to generally decrease with increasing chain length whereas the octanol-water partition coefficient logKow seems to increase. Estimated bioconcentration factors (BCF) of aliphatic acids calculated using EPI Suite v4.10 are below 100 indicating a low potential for bioaccumulation OECD SIDS (2014). This is mainly attributable to the fact that fatty acids are readily biodegradable in the environment and will also rapidly be degraded in the animal body by the β-oxidation pathway (e.g. essential process in the citric acid cycle). Hence, fatty acids are not expected to bioaccumulate (EU RAR Zinc distearate, 2008).

(III) BCF values (BCFBAF v3.01; EPI Suite v4.1; regression-based log BCF estimates) were estimated for tall oil based on QSAR taking into account its major components, oleic and linoleic acid (C18 fatty acids) as well as palmitric acid (C16 fatty acid). Based on experimental log Kow values (amounting to 7.64, 7.05 and 7.17 for oleic, linoleic and palmitric acid, respectively), a regression-based log BCF was estimated with 1.75 L/kg (corresponding to a BCF of 56.2 L/kg) for each of the three fatty acids.

In summary, QSAR-based estimates and a ready biodegradability indicate a low bioaccumulation potential for C16-18 fatty acids. Thus, performing further bioaccumulation tests of tall oil is from a scientific point of view not expected to provide more insight into the environmental fate and is not considered necessary for the environmental hazard assessment. The need for such testing is waived in consideration of animal welfare.

 

References:

 

OECD SIDS initial assessment profile- aliphatic acids (2014), CoCAM 6 September 30-October 3, Italy/ICCA, p. 41

HERA (2003). Human & Environmental Risk Assessment on ingredients of European household cleaning products. Fatty Acid Salts (Soap) Environmental Risk Assessment

EU Risk Assessment Report, RAR - Zinc distearate (2008), CAS No. 557-05-1 & 91051-01-3. PART 1 Environment, p. 63

U.S. Environmental Protection Agency, U.S. EPA (2008). Ammonium nonanoate (031802) Fact Sheet, OPP Chemical Code: 031802, p. 2

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