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EC number: 250-705-4
CAS number: 31566-31-1
Justification for grouping of substances and read-across
The Glycerides category covers aliphatic (fatty) acid esters of
glycerol. The category contains both well-defined and UVCB substances
with aliphatic acid carbon chain lengths of C2 (acetate) and C7-C22,
which are mostly linear saturated and even numbered. Some of the
substances in the category contain unsaturated fatty acids (e.g. oleic
acid in 2,3-dihydroxypropyl oleate, CAS 111-03-5 or general fatty acids
C16-22 (even) unsaturated in Glycerides, C14-18 and
C16-22-unsatd., mono- and di-, CAS 91744-43-7). Some category members
contain branched fatty acids. Branching is mostly methyl groups (e.g.
isooctadecanoic acid, monoester with glycerol, CAS 66085-00-5 or
1,2,3-propanetriyl triisooctadecanoate, CAS 26942-95-0). In one category
member the branching cannot be located precisely (Glycerides, C16-18 and
C18-unsatd., branched and linear mono-, di- and tri, ELINCS 460-300-6).
Hydroxylated fatty acids are present in three substances (Castor oil,
CAS 8001-79-4; castor oil hydrogenated, CAS 8001-78-3 and
2,3-dihydroxypropyl 12-hydroxyoctadecanoate, CAS 6284-43-1).
Hydroxylation occurs on C12 of stearic acid in all these
substances. Acetylated chains are present in the last part of the
category, comprising fatty acids from C8 to C18 (even) and also C18
unsaturated, additionally a C18 acetylated fatty acid is present with
the acetic acid located in C12 position (e.g. Glycerides, castor oil
mono-, hydrogenated acetates / 12-acetoxy-octadecanoic acid,
2,3-diacetoxy, CAS 736150-63-3). All glycerides build mono-, di- and
tri-esters in variable proportions.
The available data allows for an accurate hazard and risk assessment of
the category and the category concept is applied for the assessment of
environmental fate, environmental and human health hazards. Thus where
applicable, environmental and human health effects are predicted from
adequate and reliable data for source substance(s) within the group by
interpolation to the target substances in the group (read-across
approach) applying the group concept in accordance with Annex XI, Item
1.5, of Regulation (EC) No 1907/2006. In particular, for each specific
endpoint the source substance(s) structurally closest to the target
substance is/are chosen for read-across, with due regard to the
requirements of adequacy and reliability of the available data.
Structural similarities and similarities in properties and/or activities
of the source and target substance are the basis of read-across.
A detailed justification for the grouping of chemicals and read-across
is provided in the technical dossier (see IUCLID Section 6.1 and Section
13) and within chapter 7.1 of the CSR.
The Terrestrial toxicity parameters of the Glycerides category are
presented in the table below.
Toxicity to soil macroorganisms except arthropods
Toxicity to terrestrial arthropods
Toxicity to terrestrial plants
Toxicity to soil microorganisms
RA: CAS 91052-28-7
Waiving based on CSA
Weight of Evidence (WoE)
NOEC ≥ 1000 mg/kg
RA: CAS 620-67-7
NOEC ≥ 1000 mg/kg dw
EC50 (21 d) > 61 mg/kg soil dw
Weight of Evidence (WoE
Weight of Evidence (WoE)
Exposure based waiving
Category members subject to the REACh Phase-in registration deadline of
31 May 2013 are indicated in bold font.
Substances that are either already registered under REACh or not subject
to the REACh Phase-in registration deadline of 31 May 2013 are indicated
in normal font.
Surrogate substances are either chemicals forming part of a related
category of structurally similar fatty acid esters or
precursors/breakdown products of category members (i.e. alcohol and
fatty acid moieties). Available data on these substances are used for
assessment of (eco )toxicological properties by read-across on the same
basis of structural similarity and/or mechanistic reasoning as described
below for the present category.
Two studies investigating the toxicity of Glycerides to soil
macroorganisms are available for the monoconstituent substance
propane-1,2,3-triyl trisheptanoate (CAS 620-67-7, triglyceride, C7 fatty
acid) and the UVCB substance Glycerides, C14-18 and C16-18 unsatd,
mono-, di- and tri- (CAS 91052-28-7). The Glycerides category members
(with the exception of 2,3-dihydroxypropyl laurate (CAS 142-18-7)) show
high adsorption potential based on log Koc values >3. Therefore, tests
conducted on soil-dwelling organisms that feed on soil particles (such
as earthworms or arthropods) are most relevant for the evaluation of
terrestrial toxicity of these substances (Guidance on information
requirements and chemical safety assessment, Chapter R7.b (ECHA, 2012)).
Propane-1,2,3-triyl trisheptanoate (CAS 620-67-7) and Glycerides, C14-18
and C16-18 unsatd, mono-, di- and tri- (CAS 91052-28-7) cover the whole
fatty acid C-chain range within the Glycerides category and also
different degrees of esterification. Therefore, these two substances are
expected to be good representatives of the toxicity of Glycerides to
soil macroorganisms. Both tests were performed according to OECD 207,
under GLP conditions (Muckle, 2012; Moser, 2012). The test organisms
Eisenia fetida was exposed to the respective test substance for 14 days
at a concentration of 1000 mg/kg dw (limit tests). No effects on
survival or biomass were reported during the exposure period, leading to
NOEC values ≥ 1000 mg/kg dw. Based on these results, toxicity to soil
macroorganisms is not anticipated within the Glycerides category.
Furthermore, literature data evaluating the effects of fatty acid
esters, including one of the Glyceride category members (Glycerol
tristearate, CAS No. 555-43-1) to soil microorganisms are available.
Hita et al. (1996) investigated the degradation of the model molecule
tristearin (Glycerol tristearate) in three different soils for 4 weeks.
The amount of stearic acid increased in considerable amounts during the
experiment showing the hydrolytic activity of lipases breaking the ester
bonds. Furthermore, the investigation of ester fractions showed the
generation of new alkanoic acids (methyl stearate, ethyl stearate and
propyl stearate) which were not determined in the controls. Nevertheless
the amounts were no longer present after 4 weeks, which leads to the
assumption that degradation by soil microorganisms had occurred. The
same was shown by Cecutti et al. (2002) and Banchio and Gramajo (1997)
for other fatty acid esters. Effects on soil microorganisms are thus not
expected to be of concern for the Glycerides category members.
A rapid and ultimate degradation of the Glycerides category members in
all environmental compartments, including soil, can be expected. All
substances of the Glycerides category are readily biodegradable. Chronic
exposure of terrestrial organisms is thus very unlikely. Due to the
metabolization via enzymatic hydrolysis of the Glycerides category
members, a relevant uptake and bioaccumulation in biota is not expected.
Enzymatic breakdown will initially lead to the free fatty acid and
glycerol (and for this substance additionally acetic acid). Glycerides
are naturally stored by organisms as long-term energy reserves.
Especially in periods in which the energy demand is high (reproduction,
migration, etc.), glycerides are mobilized from the storage sites as
source of fatty acids. Fatty acid catabolism is the most important
energy source in many species, resulting in the release of acetyl CoA
and NADH (throughβ-oxidation) and eventually, via the tricarboxylic
cycle, the production of metabolic energy in the form of ATP (Tocher,
Acute and chronic values obtained in tests conducted on fish,
invertebrates, algae and microorganisms showed no adverse effects in the
range of the water solubility of the substances (or the highest
attainable solubility in aqueous medium), with the exception of
Glycerides, palm-oil mono-, hydrogenated, acetates (CAS 93572-32-8) and
2,3-dihydroxypropyl laurate (CAS 142-18-7). The substances are
classified as environmental hazard Chronic category 3, according to
Regulation (EC) No. 1272/2008, and exposure based waiving is performed
to cover the terrestrial endpoints (based on RCR < 1). Based on the
information gathered from different taxonomic groups, in combination
with the ready biodegradability and rapid metabolization of these
substances, it can be concluded that toxicity to terrestrial organisms
is highly unlikely for the Glycerides category members.
A detailed reference list is provided in the technical dossier (see
IUCLID, section 13) and within the 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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