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EC number: 304-780-6
CAS number: 94279-36-4
The bioaccumulation potential is low.
No experimental data is available on the bioaccumulation potential of
the PFAE aromatic category members. Therefore, all available related
data are combined in a Weight of Evidence approach (WoE), which is 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.
1907/2007 Annex IX and X.
Bioaccumulation refers to the uptake of a substance from all
environmental sources including water, food and sediment. However, the
accumulation of a substance in an organism is determined, not only by
uptake, but also by distribution, metabolism and excretion. Accumulation
takes place if the substance is taken up faster than it can be
metabolised and/or excreted.
In the case of the PFAE aromatic category members, uptake of dissolved
substance via water is expected to be low, since the substances can be
effectively removed in conventional STPs by biodegradation and sorption
to biomass due to their enhanced ultimate biodegradability and high
potential for adsorption (calculated log Koc > 5, KOCWIN v2.00).
Furthermore, the low water solubility (< 0.05 mg/L) and high estimated
log Kow values (calculated log Kow > 10, KOWWIN v1.68) indicate that the
members of the PFAE aromatic category are highly lipophilic. If released
into the aquatic environment, the category members undergo extensive
biodegradation and sorption on organic matter, as well as sedimentation.
Thus, the bioavailability of these substances in the water column is
reduced rapidly, which reduces the probability of uptake by aquatic
organisms (e.g., see McKim et al, 1984; Björk, 1995; Haitzer et al.,
Therefore, the relevant uptake route of PFAE aromatic category members
in organisms is considered predominately to be by ingestion of particle
If the substance is taken up by ingestion, absorption of the members of
the PFAE aromatic category is expected to be low based on the molecular
weight, size and structural complexity of the substances. These large
and complex structures assume a high degree of conformational
flexibility. Dimitrov et al. (2002) revealed a tendency of decreasing
log BCF with an increase in conformational flexibility of molecules.
They suggest that this effect is related to the enhancement of the
entropy factor on membrane permeability of chemicals. This concludes a
high probability that the substance may encounter the membrane in a
conformation which does not enable the substance to permeate.
Furthermore, the members of the PFAE aromatic category have high
molecular weights of 546 to 757 g/mol. Thus, it is unlikely that they
are readily absorbed, due to the steric hindrance of crossing biological
membranes. Following the ‘rule of 5’ (Lipinski et al., 2001), developed
to identify drug candidates with poor oral absorption based on criteria
regarding partitioning (log Kow >5) and molecular weight (>500 g/mol),
the substances are considered to be poorly absorbed after oral uptake
(also see Hsieh & Perkins, 1976).
However, ingested molecules of the PFAE aromatic category members can
undergo a stepwise hydrolysis into the respective alcohol as well as the
di- or monoester and the aromatic acid by gastrointestinal enzymes
((Lehninger, 1970; Mattson and Volpenhein, 1972) Further metabolism is
expected for that part of the substance that has been absorbed. During
the first step of alcohol metabolism, the alcohols are oxidised to the
corresponding carboxylic acids, followed by a stepwise elimination of
C2-units in the mitochondrial beta-oxidation process (OECD SIDS, 2006).
1,2,4-Benzene tricarboxylic acid might be further metabolized by
beta-oxidation, the degradation pathway of fatty acids after cleavage of
the aromatic ring. Excretion of the metabolites is expected via urine or
via expired air as CO2 after metabolic degradation.
The interaction between lipophilicity, bioavailability and membrane
permeability is considered to be the main reason why the relationship
between the bioaccumulation potential of a substance and its
hydrophobicity is commonly described by a relatively steep Gaussian
curve with the bioaccumulation peak approximately at log Kow of 6-7
(e.g., see Dimitrov et al., 2002; Nendza & Müller, 2007; Arnot and Gobas
2003). Substances with log Kow values above 10, which have been
calculated for the members of the PFAE aromatic category, are considered
to have a low bioaccumulation potential (e.g., Nendza & Müller, 2007;
Furthermore, for those substances with a log Kow value > 10 it is
unlikely that they reach the pass level of being bioaccumulative
according to OECD criteria for the PBT assessment (BCF > 2000 L/kg;
ECHA, 2012). This assumption is supported by QSAR calculations using
BCFBAF v3.01 performed for the PFAE aromatic category members. BCF/BAF
values of 0.89 L/kg and 0.89-10.92 L/kg were obtained (Arnot-Gobas
estimate, including biotransformation, upper trophic). Even though the
members of the PFAE aromatic category are outside the applicability
domain of the model, the estimation can be used as supporting indication
of low bioaccumulation potential. The model training set is only
consisting of substances with log Kow values of 0.31 - 8.70. But it
supports the statement that substances with high log Kow values (> 10)
have a lower potential for bioconcentration as summarized in the ECHA
Guidance R.11 and they are not expected to meet the B/vB criterion
The members of the PFAE aromatic category are characterized by a low
water solubility (< 0.05 mg/L), high log Kow values (> 10) and high
molecular weights (546-757 g/mol). Based on the physico/chemical
properties such as low water solubility and high potential for
adsorption a reduced availability in water is expected. The high
molecular weight of the substance significantly reduces the absorption
due to steric hindrance to cross biological membranes. Absorbed
molecules will be metabolized and the metabolites will be excreted. It
can be concluded that the bioaccumulation potential of the PFAE aromatic
category members is negligible. BCF/BAF values estimated by QSAR (BCFBAF
v3.01) also support this assumption (BCF values all well below 2000
L/kg). Taking all these information into account, it can be concluded
that bioaccumulation of the PFAE aromatic category members is unlikely
A detailed reference list is provided in the technical dossier
(see IUCLID, section 13) and within CSR.
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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