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EC number: 500-148-0
CAS number: 61788-89-4
In accordance with Regulation (EC) No 1907/2006, Annex IX, 9.3.2, column 2 a bioaccumulation study does not need to be conducted as the substance has a low potential for bioaccumulation and a low potential to cross biological membranes.
Due to the properties of the Dimerised Fatty Acids category members,
their bioaccumulation potential in aquatic organisms is assumed to be
The Dimerised Fatty Acids are relatively large molecules (C16-18 as
monomers, C36 as dimers and C54 as trimers) with high molecular weights
(monomenric acids: ≈ 282 g/mol, dimeric acids 561 g/mol, trimeric acids
838 g/mol). Thus, they have a low potential to cross biological
membranes (Lipinski et al., 2001).
From the toxicokinetic behaviour of mono- and oligomeric acids in
mammals it can be assumed that unsaturated monomeric C16-C18 fatty acids
are more readily absorbed than saturated fatty acids like octadecanoic
and isooctadecanoic acid but less readily than fatty acids with shorter
chain length. Very low absorption is reported for dimeric and trimeric
fatty acids via the gastro intestinal tract and thus, most of the
ingested fatty acids will be excreted in the faeces (≥ 80% for dimeric
acid methyl esters (Hsieh and Perkins, 1976; Paschke et al. 1964)). In
case of absorption fatty acids will undergo rapid metabolism and
excretion (either in the expired CO2 or as hydroxylated or conjugated
metabolite in the urine in the case of cyclic fatty acids) as they feed
into physiological pathways like the citric acid cycle, sugar synthesis,
and lipid synthesis.
Hence, no significant bioaccumulation in animal tissue is expected for
Dimerised Fatty Acids due to general low absorbed amounts and their
metabolic fate in organisms.
Furthermore, as dimerised fatty acids have very low water solubilities
(sub-category dimers and trimers: < 0.52 mg/L), only low concentrations
in the aquatic environment and thus low concentrations in aquatic
organisms can be expected at all. The U.S. EPA HPV report (2009) states
an expected low bioaccumulation potential based on the negligible
solubility and their anionic nature.
In conclusion, Fatty acids, C18-unsaturated, dimers (CAS No. 61788-89-4)
does not pose a risk to organisms in regard to
bioaccumulation/biomagnification, consequently in accordance with
Regulation (EC) No 1907/2006, Annex IX, 9.3.2, column 2 a
bioaccumulation study does not need to be conducted as the substance has
a low potential for bioaccumulation and a low potential to cross
Hsieh, A. and Perkins, E.G. (1976). Nutrition and Metabolic Studies of
Methyl Ester of Dimer Fatty Acids in the Rat. Lipids, 11(10):763-768.
Lipinski et al. (2001) Experimental and computational approaches to
estimate solubility and permeability in drug discovery and development
settings, Adv. Drug Del. Rev., 2001, 46, 3-26.
Paschke, R.F. et al. (1964). Dimer acid structures. The dehydro-dimer
from methyl oleate and Di-t-butyl peroxide. Journal of the American Oil
Chemists' Society 41(1):56-60.
U.S. Environmental Protection Agency (2009). Risk-Based Prioritization
Document. Initial Risk-Based Prioritization of High Production Volume
(HPV) Chemicals – Fatty Acid Dimers and Trimer Category. pp 1-19. Report
date: April 2009.
Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.
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