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EC number: 284-895-5
CAS number: 84989-06-0
The fraction of tar acids, rich in 2,4- and 2,5-dimethylphenol, recovered by distillation of low-temperature coal tar crude tar acids.
The PBT Assessment for D-Glucopyranose,
oligomeric, undecyl glycoside (CAS 98283-67-1) is based on the criteria
set out in the “Guidance on information requirements and chemical safety
assessment, Chapter R.11: PBT Assessment” (ECHA, 2012).
No data on Tar acids, Xylenol fraction (CAS
84989-06-0) itself are available. However, the biodegradation potential
was assessed based on numerous data available for the constituents of
Tar acids, Xylenol fraction (CAS 84989-06-0).
Although there is evidence that constituents like
cresols, ethylphenols or some xylenols are readily biodegradable Tar
acids, Xylenol fraction (CAS 84989-06-0) is considered as inherently
biodegradable since rapid degradation cannot be shown for all
constituents of the UVCB.
Results on the biodegradation in sediment provide
evidence that these constituents will be ultimately degraded under
aerobic conditions with half-lives between 9.4 and 43 h for p-cresol in
water and between 5.9 and 11 h in water/sediment systems. In so-called
eco-cores, p-cresol degraded with half-lives between 3.0 and 16 h. In
simulation studies with soil o-cresol degraded with half-live times of
1.6 d for sandy loam and 5.1 d for sandy silt loam. m-cresol degraded
with half-live times of 0.6 d for sandy loam and 11.3 d for sandy silt
loam. Therefore, the substance has a low potential for accumulation in
soil and sediment.
Since rapid degradation cannot be shown for all
constituents of Tar acids, Xylenol fraction (CAS 84989-06-0) the
persistency criteria cannot finally be assessed and the substance needs
to be considered as potentially P and vP.
In accordance with ECHA Guidance R.11 (ECHA,
2017) Tar acids, xylenol fraction (CAS 84989-06-0) is not considered to
meet the screening criterion for bioaccumulation in aquatic species.
This is based on an analogue read-across approach. Available data for
all main components of Tar acids, xylenol fraction (CAS 84989-06-0)
demonstrate the log Kow to be below 3, i.e. xylenol-isomers: 2.09 to
2.42 (DEZA, 2010; EPA, 2010; Sangster, 1989); cresol-isomers: 1.94 to
1.98 (OECD SIDS, 2003; Sangster, 1989); ethyl-phenols: 2.09 to 2.58
(DEZA, 2010; Umeyama et al., 1971; Sangster, 1989), or
trimethyl-phenols: 2.67 to 2.73 (Sangster, 1989). Thus, all available
log Kow values for all main components of Tar acids, xylenol fraction
(CAS 84989-06-0) are below the trigger value of 4.5.
However, according to ECHA Guidance R.11
(ECHA, 2017) there is indication that accumulation in air breathing
organisms might occur based on log Koa values slightly above the trigger
value of >5 (5.45 - 7.08) exemplarily calculated for some representative
components, i.e. 2,4-xylenol (CAS 105-67-9), m-cresol (CAS 108-39-4) and
4-ethylphenol (CAS 123-07-9), in combination with the log Kow > 2.
These screening values (Kow and Koa) referred
to in the ECHA Guidance R.11 are a function of the modelled organisms,
food webs and environments used to obtain these values. To develop this
partition coefficient combination it was clearly indicated in the
guidance that biomagnification potential is only assumed for substances
with high chemical absorption efficiency from the diet, no
biotransformation after absorption and negligible active transport (in
Since there are no studies available in which
the toxicokinetic behavior of tar acid, xylenol fraction (CAS
84989-06-0) has been investigated in accordance with Annex VIII, Column
1, Section 8.8.1, of Regulation (EC) No 1907/2006 and with Guidance on
information requirements and chemical safety assessment Chapter R.7c:
Endpoint specific guidance (ECHA, 2017), an assessment of the
toxicokinetic behavior of tar acid, xylenol fraction is conducted to the
extent that can be derived from the relevant available information. This
comprises a qualitative assessment of the available substance-specific
data on physico-chemical and toxicological properties according to
Guidance on information requirements and chemical safety assessment
Chapter R.7c: Endpoint specific guidance (ECHA, 2017) and taking into
account further available information on surrogate substances and
The evaluation of the toxicokinetic behavior
indicates that Tar acid, xylenol fraction (CAS 84989-06-0) is expected
to be well absorbed via the oral route. Mechanisms by which substances
can be absorbed in the gastro-intestinal (GI) tract include the passage
of small water-soluble molecules (molecular weight up to around 200)
through aqueous pores or carriage of such molecules across membranes
with the bulk passage of water. As the test substance and its
constituents are soluble in water and have a relatively low molecular
weight, this passive diffusion will be the predominant mechanism for
absorption in the GI tract. In addition moderate octanol/water partition
coefficient (log Kow) values (between -1 and 4) are favorable for
absorption by passive diffusion, being applicable for the test substance
and it constituents. Following the above it can be concluded that the
test substance and its constituents will result in a high systemic
exposure after oral administration. For hazard and risk assessment
purposes oral absorption of the tar acid, xylenol fraction is set to
100%. The results of the toxicity studies with cresol isomers and
xylenol isomers do not provide reasons to deviate from this proposed
As regards distribution, once absorbed the
water soluble tar acid, xylenol fraction (CAS 84989-06-0) and its
constituents are expected to widely distribute through the body. Its
moderate lipophilic character indicates that they are likely to
distribute into cells and the intracellular concentration may be higher
than extracellular concentration. Wide distribution through the body is
confirmed from the histopathologic findings in the repeated dose studies.
Considering metabolism, Tar acid, xylenol
fraction (CAS 84989-06-0) and its constituents are expected to undergo
Phase I reactions including aliphatic and aromatic hydroxylation and
further oxidation. Phase II reactions, including glucuronidation and
sulfation, will further increase water solubility.
Based on the high water solubility and the
low molecular weight, tar acid, xylenol fraction (CAS 84989-06-0) and
its conjugation products are expected to be mainly excreted in the urine.
Thus, with reference to the toxicokinetic
behavior Tar acid, xylenol fraction (CAS 84989-06-0) is expected to be
well absorbed via the oral, dermal and inhalation route. Absorption
factors of 100% are proposed for all routes. The substance is
anticipated to be widely distributed through the body, metabolized and
excreted mainly in the urine. No bioaccumulation potential is expected.
In conclusion, the trigger values for
biomagnification in air-breathing (terrestrial) organisms as stipulated
in the ECHA Guidance R.11 are likely to overestimate the potential for
biomagnification in the food chain. Even though absorption via oral
exposure is likely the described metabolic and excretion pathways are
expected to minimize biomagnification in the food chain.
Thus, Tar acids, xylenol fraction (CAS 84989-06-0)
exhibits a low potential for bioaccumulation and is not B and not vB.
Considering the environment the lowest availabe
chronic value among all trophic levels, species and environmental
compartments is a NOEC of 1 mg/L for the constituents p-cresol.
Furthermore, according to Directive 67/548/EEC no classification applies
for carcinogenicity (category 1 or 2), mutagenicity (category 1 or 2) or
toxicity to reproduction (category 1, 2, or 3) and/or no classification
applies according to the consolidated version of Regulation (EC) No
1272/2008 and further amendments (ATPs) for carcinogenicity (category 1A
or 1B), germ cell mutagenicity (category 1A or 1B) or toxicity to
reproduction (category 1A, 1B, or 2). Further, there is no evidence of
chronic toxicity, as indentified by the classifications T, R48 or Xn,
R48 according to Directive 67/548/EEC or specific target organ toxicity
after repeated exposure (STOT RE category 1 or 2) according to
Regulation EC No 1272/2008.
Therefore, Tar acids, xylenol fraction (CAS
84989-06-6) is not toxic and is considered not T.
In summary Tar acids, xylenol fraction (CAS
84989-06-0) is not PBT/vPvB.
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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