Tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate

Endpoint summary

Key value for chemical safety assessment

Effects on fertility

Description of key information

Key_Read-across - Toxicity to reproduction, OECD 421; NOELs for systemic toxicity 100 and 1000 mg/kg/day for males and females respectively. The NOEL for reproductive / developmental toxicity is considered to be 1000 mg/kg/day for offspring.

Supporting_Read-across - toxicity to reproduction, OECD 422; NOELs are considered to be 500 mg/kg/day for both reproductive toxicity and developmental toxicity. The NOEL is considered to be 1000 mg/kg/day for males and female offspring.

Link to relevant study records

Reference

Endpoint:

screening for reproductive / developmental toxicity

Type of information:

read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

key study

Justification for type of information:

REPORTING FORMAT FOR THE ANALOGUE APPROACH

INTRODUCTION
In order to fulfil the information requirements according to Annex VIII to Regulation (EC) No1907/2006 which applies for tonnages in the range between 10 and 100 tonnes/year, data on physico-chemical, toxicity, ecotoxicity and environmental fate properties of a chemical must be submitted. For the registration of tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate (EC No 221-508-0, CAS No 3126-80-5), available experimental data are confined to some physical-chemical and environmental fate information. Further information, notably for toxicicological and ecotoxicological endpoints, can be obtained from studies using the source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate, with the abbreviation TOTM (EC No 222-020-0, CAS No 3319-31-1). Data on structurally related ester compounds with other aliphatic alcohols can strengthen the read-across approach. In this regard, trioctyl benzene-1,2,4-tricarboxylate is considered as supporting compound.

The read-across justification relies on the principles detailed in the Guidance on information requirements and chemical safety assessment, Chapter R.6: QSARs and grouping of chemicals (ECHA, 2008), and the Read-Across Assessment Framework document (ECHA, 2017). The read-across hypothesis implies that different, but structurally similar compounds produce the same type of effects, or both are characterized by the absence of effects (analogue approach - Scenario 2). The properties of the target substance are predicted to be quantitatively equal or lower when compared to those of the source substance (worst-case prediction). Similar but not identical (bio-)transformation products or metabolites with the same type of functional groups may occur but are not exclusively the basis for the read-across hypothesis.

The source and the supporting compounds are characterized by a low-toxicity profile, with minor concerns arising from repeated dose and reproduction toxicity testing of the source substance. Due to the low systemic toxicity, information on the mode of action is limited which otherwise could be used to improve the read-across hypotheses. On the other hand, regarding the environmental fate, the source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate is known to be not readily biodegradable.

It will have to be shown that tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate (TOTM) and tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate do not share the properties, especially the mammalian toxicity, of phthalates such as bis(2-ethylhexyl) phthalate, with the abbreviation DEHP (EC No 204-211-0, CAS No 117-81-7), which proved to be an endocrine disruptor. Toxicokinetic studies in mammals indicate significant differences in gastrointestinal hydrolysis, metabolism and absorption between TOTM and DEHP which can explain the dissimilarity in the toxicity profile.


1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The rationale for the hypothesis is described in the Guidance on information requirements and chemical safety assessment, Chapter R.6: QSARs and grouping of chemicals (ECHA, 2008), and the Read-Across Assessment Framework document (ECHA, 2017). The read-across hypothesis implies that different, but structurally closely related compounds produce the same type of effects, or are characterized by the absence of effects, due to similar, biological active or inactive structural characteristics (analogue approach - Scenario 2).

Here, the properties of the target substance are predicted to be quantitatively equal or lower when compared to those of the source substance which represent the worst-case. This assumption is based on the observation that the toxicity decreases with an increasing number of formic acid residues attached to the phenyl ring (2 in phthalates, 3 in the source, 4 in the target compound). An explanation for this observation would be that the hydrolysis rate decreases with an increasing number of formic acid residues which are in an ester bond with 2-ethylhexan-1-ol. At the same time, resorbable mono-esters are formed to a lower extend. The sub-structure feature, which is shared by phthalates as well as the source and target compound, is phthalic acid, synonym 1,2-benzenedicarboxylic acid. Except for the hydrolysis product 2-ethylhexan-1-ol, which seems to be of low toxicological relevance, the biotransformation products or metabolites are similar as they show the same type but not the same number of functional groups. Details are reported in sections 4.1-3.

Moreover, lower toxicity of the target is also expected since the phthalate DEHP is specified as an impurity of the source but not of the target compound. Actually, the low concentrations of DEHP present as an impurity showed no significant influence on the outcome of toxicity studies. Thus, the hazard values established for the source substance constitute a worst-case because the target substance is less potent in terms of biological effects (“inert”).

For the source chemical, a comprehensive database is available which shows that the substance has a low toxicity profile. Irritating/corrosion effects on skin and eye, and skin sensitization were not observed. An OECD 422 screening test did not indicate developmental toxicity effects. Only marginal effects on reproductive organs were considered as not adverse. Observed changes in clinical chemistry parameters and liver weights of lower toxicological relevance could have been caused by an adaptive response. The target chemical is expected to share the low toxicity profile due to similar structural features.

Although the target and source chemicals are proposed by OECD Toolbox (v. 4.1) profiling to be attributed to the OECD HPV Chemical Category of High molecular weight phthalate esters this not constructive for the prediction of (eco-) toxicological effects. Well established differences in toxicokinetics (absorption, metabolism) of the source chemical and supporting compounds in comparison to phthalate esters such as bis(2-ethylhexyl) phthalate (DEHP, EC No 204-211-0, CAS No 117-81-7) can endorse this view and provide an explanation for the divergence in the biological activity found in toxicity and ecotoxicity studies. All these outlined arguments will be elucidated in more detail in the following sections.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
The compound to be registered, tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate (EC No 221-508-0, CAS No 3126-80-5), with the IUPAC name 1,2,4,5-tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, is a mono constituent substance in the physical form of a liquid (also identified as tetra(2-ethylhexyl) pyromellitate, common name tetraoctyl pyromellitate, abbreviation TOPM). The purity grade is ≥ 99 % (w/w), with water and ethanol as main impurities.

The source, specified as tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate (EC No 222-020-0, CAS No 3319-31-1), is also a mono constituent chemical. The following alternative names are known:1,2,4-tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate, TOTM, tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate, and tris(2-ethylhexyl) trimellitate. The common name is trioctyl trimellitate. According to information on the appearance, physical state, and colour of the registered source substance, the substance is liquid at standard temperature and pressure with pale yellow colour and faint odour. The purity grade is in the range between 98.29% and 100% (w/w). Chemical analysis revealed bis(2-ethylhexyl) phthalate (abbreviation DEHP, EC No 204-211-0, CAS No 117-81-7) as an impurity which is found in the concentration range from 0.0 to 0.07% (w/w), with a typical concentration of 0.05% (w/w). The identity of other impurities is unknown.

Identity of the source and target substance:

Chemical Target substance Source substance
EC number 221-508-0 222-020-0
EC name Tetrakis(2-ethylhexyl) Tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate
benzene-1,2,4,5-tetracarboxylate
CAS number 3126-80-5 3319-31-1
IUPAC name 1,2,4,5-tetrakis(2-ethylhexyl) Tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate
benzene-1,2,4,5-tetracarboxylate
Other names Tetra(2-ethylhexyl) pyromellitate, 1,2,4-tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate, TOTM, tris(2-ethylhexyl)
tetraoctyl pyromellitate, trimellitate, trioctyl trimellitate.
abbreviation TOPM
Molecular formula C33H54O6 C33H54O6
Smiles CCCCC(CC)COC(=O)c1cc(C(=O)OCC CCCCC(CC)COC(=O)c1ccc(C(=O)OCC(CC)CCCC)c(c1)C(=O)OCC(CC)CCCC
(CC)CCCC)c(cc1C(=O)OCC(CC)CCCC)C(=O)OCC(CC)CCCC
Molecular weight 702.507 g/mol 546.7783
Description Discrete chemical, mono constituent, organic Discrete chemical, mono constituent, organic
Physical form Liquid at 25°C Liquid at 25°C
Purity grade ≥ 99 % (w/w) 98.29%-100% (w/w)
Impurities Water and ethanol 0.0-0.07% (w/w) bis(2-ethylhexyl) phthalate (EC No 204-211-0),
and impurities of unknown identity

3. ANALOGUE APPROACH JUSTIFICATION
[Summarise here based on available experimental data how these results verify that the read-across is justified]

Functional groups and substituents
The chemical structures of the target and the source substances can be described as esters of 2-ethylhexanol with pyromellitic acid and trimellitic acid, respectively. Four or three formic acid residues which show an ester bond with branched alkane substituents are attached to an aromatic ring (benzol), respectively. The organic functional groups are specified in Table 3 (see attached 'Read-across justification' in IUCLID section 13.2) which shows that the target and the source chemical are characterized by the same type of organic functional groups. Only the number of ‘carboxylic acid esters’ with ‘alkanes, branched with tertiary carbon’ is varying (4 vs 3, respectively). The sub-structure feature, which is shared by phthalates as well as the source and target compound, is phthalic acid, synonym 1,2-benzenedicarboxylic acid. The conformation, i.e. spatial arrangement of atoms in the molecules of the target and the source substance, is flexible.

PubChem substructure similarity features
The structural similarity of the target and source read-across substances has in addition been verified by application of PubChem substructure similarity features which are implemented in OECD Toolbox (v. 4.1).

Method: The PubChem generates a substructure fingerprint for each chemical structure. These fingerprints are used for similarity neighboring. In this context, a substructure is a fragment of chemical structure. A fingerprint is an ordered list of binary (1/0) bits. Each bit represents a Boolean determination of specific atom or test features. 7 groups of PubChem features have been defined:
• Hierarchical element counts;
• Rings;
• Simple atom pairs;
• Simple atom nearest neighbors;
• Detailed atom neighbors;
• Simple SMARTS patterns (SMART is a language that allows specifying substructures by using rules that are straightforward extensions of SMILES);
• Complex SMARTS patterns.

Results: The target compound shares 111 out of 112 substructure features with the source whereas the source compound shares 111 out of 113 substructure

The assessment of similarities in compounds the organism is exposed to relies on experimental data regarding the toxicokinetics of tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate as well as the prediction of hydrolysis products and metabolites by OECD Toolbox (v. 4.1) both for the source and target read-across substance. Hydrolysis of ester bonds by intestinal and liver esterases is also well established (Younggil, 2001). Moreover, substantial information on in vivo metabolism of phthalates such as mono(2-ethylhexyl) phthalate (MEHP, CAS No 4376-20-9, EC No 224-477-1) is considered since differences in metabolism can endorse the view that tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate and tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate are less toxic than low molecular weight phthalates.

Please refer to IUCLID section 7.1.1 'Basic toxicokinetis' and IUCLID section 13.2 'read-across justification' for detiailed information about absorption, distribution, metabolism and excretion of the source and target substance.

Prediction of metabolites by the hydrolysis simulator (acidic) and hydrolysis simulator (basic) resulted in an identical set of 7 metabolites in each case for tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, and a set of 8 metabolites for tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate. Obviously, the prediction is based on the assumption that the ester bonds of trimellitic acid and pyromellitic acid, respectively, are successively hydrolysed, with the result that all of the possible isomers are released. An overview of predicted hydrolysis products and compounds yielded by the metabolism simulators is presented below, along with experimental data.

Summary of toxicokinetics with conclusions on similarities:

Hydrolysis by esterases is considered to be an important first step in the oral absorption of ortho-phthalates. The potential for such hydrolysis to occur with the source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate has been examined in an in-vitro study using rat gut homogenate. There was no evidence of hydrolysis occurring wheras the corresponding phthalate, bis(2-ethylhexyl) phthalate (abbreviation DEHP, EC No 204-211-0, CAS No 117-81-7), was significantly hydrolysed.
The absorption, distribution, metabolism and elimination of the radiolabeled source substance have been investigated in the rat following oral administration of a single dose. Recovery of the administered dose was 94%, with approximately 75% eliminated unchanged in the faeces, 16.3% found in the urine and 1.9% in expired air. Residual radioactivity in the carcass after 6 days was <0.6% of the administered dose. Findings indicate that the compound may be partially hydrolysed in the gastro-intestinal tract to 2-ethylhexan-1-ol and the corresponding di-ester and, following further hydrolysis, the mono-ester. Only 2-ethylhexanol and a single isomer of the monoester (i.e. mono-(2-ethylhexyl) trimellitate) appear to be absorbed. Following absorption, 2-ethylhexanol was extensively metabolised with metabolites eliminated in the urine and as expired 14CO2. There was no evident metabolism of mono-(2-ethylhexyl) trimellitate, this being eliminated unchanged. Urinary excretion of radioactivity was bi-phasic with half-lives of 3.1 and 42 hours.
When barriers to absorption are by-passed by intravenous administration, the source chemical has been found to distribute mainly in the liver, lungs and spleen. Excretion of the substance or its metabolites over 14 days was slow with 21.3% and 2.8% of the administered dose found in the faeces and urine, respectively, suggesting a half-life of approximately 40 days. While data from the intravenous route may suggest a possible concern for potential bioaccumulation, the substance is poorly absorbed by the oral route, and the kinetics of urinary elimination suggest a far shorter half-life, indicating a lower potential for bioaccumulation.
An in vitro dermal absorption study using full-thickness skin samples in a Franz diffusion cell system showed that the compound is not systemically bioavailable after dermal exposure. This finding is supported by the results of the IH SkinPerm model. Due to the low vapor pressure, a significant respiratory uptake from airborne vapors can be excluded.

Regarding similarities in chemical structures, physico-chemical properties (see below), and in addition results of OECD Toolbox profiling, similar toxicokinetic characteristics are expected for the target substance. This means that the ester bonds of tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate will probably be successively hydrolysed at a low rate in the gastrointestinal tract. The hydrolysis products 2-ethylhexan-1-ol and mono-(2-ethylhexyl) pyromellitate will likely be absorbed to a low extend. 2-Ethylhexan-1-ol but not the mono-ester will undergo further phase-I metabolism. There is no evidence that carboxyl groups of the source and target compounds are modified during phase I-metabolism, or metabolites are produced which play a role for the toxicological behavior of phthalates.
In conclusion, except for the hydrolysis product 2-ethylhexan-1-ol, the biotransformation products or metabolites of the source and target compound are similar as they show the same type but not the same number of functional groups. Available toxicokinetic data may imply that the extend of monoester formation in the gastrointestinal tract, as well as the absorption and systemic bioavailability decreases with an increasing number of ester bonds (2 ester bonds occur in phthalates, 3 in the source substance, 4 in the target substance). Therefore, it seems to be plausible that the gastrointestinal absorption of hydrolysis products of the target substance, i.e. the potential metabolites 2-ethylhexan-1-ol and mono-(2-ethylhexyl) pyromellitate, is very low. The latter metabolite will possibly not undergo a phase-I metabolism but rather be excreted unchanged in the urine, similarly to mono-(2-ethylhexyl) trimellitate. Especially due to low water solubility < 1 mg/L, the target substance is predicted by the IH SkinPerm model to be not absorbed through the skin. The low volatility of the target substance as well as the octanol-water partition coefficient (log Po/w of 6.01) will obviate a significant respiratory uptake


Synopsis of physico-chemical properties
Pyromelliate (Target) TOTM (Source)
Physical state Liquid at 20 °C and 101.3 kPa Liquid at 20 °C and 101.3 kPa
Melting / freezing point -34°C at 101,3kPa (exp.) -43 °C at 101.3 kPa (exp.)
Boiling point 573.5 °C (QSAR, SPARC by ARChem) 355 °C (exp.)
Relative density 0.9908 g/cm3 at 25 °C 0.9885 g/cm3
Granulometry Not applicable (liquid state) Not applicable (liquid state)
Vapour pressure 2.09E-9 hPa (QSAR, MPBPWIN™ 6.8E-10 hPa at 25 °C (exp.)
by EPI Suite v4.1)
Partition coefficient
n-octanol/water (log value) 6.01 (exp.) 8.00 at 25 °C and pH 4.8 (exp.)
Water solubility < 1 mg/L at 30 °C (exp.) 3.06 µg/L at 25 °C (exp.)
(identical to the cut-off value for insolubility
in water according to ECHA guidance)
Surface tension Study scientifically not necessary in accordance with ECHA guidance
Flash point 262 °C (exp.) 224 °C (exp.)
Autoflammability / self-ignition temperature Study scientifically not necessary, flash point >200 °C at 101.3 kPa
Flammability Study scientifically not necessary, flash point >200 °C at 101.3 kPa
Explosive properties Study scientifically not necessary - the substance contains no chemical groups associated with explosive properties.
Oxidising properties Based on a consideration of the chemical structure of the substance, oxidising properties do not
need to be assessed.
Stability in organic solvents and
identity of relevant degradation products The stability of the substance in organic solvents is not considered to be critical.
Dissociation constant Study scientifically not necessary - the substance does not contain any functional groups that dissociate.
Viscosity 1.7 cm2/s at 40°C 0.87 cm2/s at 40 °C (kinematic viscosity, exp.)
(kinematic viscosity, exp.)
*Published data, cf. UNEP (2002) and ECHA (2013-2017)

Based on experimental data and QSARs, the relevant physico-chemical properties of the source and target substance are similar. This supports the view that their pattern of biological effects and the underlying mechanisms may also show analogies.

The assessment of similarities in compounds the organism is exposed to (section 4.2), with reference to the corresponding Assessment Element 2.1 of the RAAF document (ECHA, 2017), relies on experimental data for the source compound and predictions (OECD Toolbox, IH SkinPerm model) combined with theoretical considerations for the target compound. Due to a very low oral and dermal absorption rate with very low systemic bioavailability, non-common compounds (with the same type but not the same number of functional groups) are considered as not relevant in vivo. On this basis, the assessment option “acceptable with medium confidence” is chosen.

Both the source and supporting compound have shown a low toxicity profile, without local and systemic toxicity effects except for minor findings, which were regarded as non-adverse, after repeated exposure to the supporting chemical. More in detail, in a Combined Repeated Dose Toxicity Study with the Reproduction/Developmental Toxicity Screening Test according to OECD TG 422 using 1,2,4-benzenetricarboxylic acid, trioctyl ester some irregularities in clinical-chemistry parameters were noted in male and female rats at the mid and/or high dose level (125 and 500 mg/kg bw/day orally, respectively). At 500 mg/kg bw/day significant changes in liver weights of females were recorded. These findings may be attributed to treatment but could represent an adaptive response.

The information presented in paragraph 4.3 suggests that the hypothesis of common underlying biological mechanisms, both in qualitative and quantitative aspects (Assessment Elements 2.2 and 2.3 according to the RAAF-document, see ECHA, 2017) is acceptable. With respect to the fact that no toxicity studies for the target compound are available, the assessment option “acceptable with just sufficient confidence” may be appropriate. For the specific case, the Assessment Elements 2.4 (Exposure to other compounds than to those linked to the prediction) and 2.5 (Occurrence of other effects than covered by the hypothesis and justification) are considered as not relevant.

Reproduction/developmental toxicity
An OECD screening study using the source substance revealed no functional changes in fertility or reproductive performance although histopathological examination indicated reduced spermatocytes and spermatids in the testes of males given the substance at doses of 300 or 1000 mg/kg/day. The NOELs for reproductive toxicity were considered to be 100 and 1000 mg/kg/day for males and females, respectively. Regarding effects on the offspring, a NOEL of 1000 mg/kg bw/day was derived from this study.
In a repeat-dose toxicity study combined with a reproductive/developmental toxicity screening test conducted on a supporting substance (the alcohol ester side chains of the molecule being linear rather than branched), no significant effect on reproductive ability, organ weight or histopathology of the ovary, delivery or maternal behaviour was apparent. The NOEL for reproductive / developmental toxicity was considered to be 500 mg/kg/day for both parents and offspring, the highest dose examined.
Overall, exposure to the source chemical and the supporting compound in reproduction/developmental screening tests up to a maximum dose level of 1000/mg/kg bw/day orally was not associated with adverse findings. Unlike DEHP, profiling results (OECD Toolbox v.4.1) indicate that structural features of the source target compound do not show alerts for estrogen receptor binding or a reproductive/developmental toxicity potential according to the DART scheme. Thus, it can be expected that the target chemical will not affect the reproductive performance or offspring development.

4. DATA MATRIX
see Section 13.2 'Read across justification' and 'Data Matrix'

Reason / purpose for cross-reference:

read-across source

Reason / purpose for cross-reference:

read-across: supporting information

Remarks:

read-across justification

Reason / purpose for cross-reference:

read-across: supporting information

Remarks:

Toxicokinetic

Vehicle:

corn oil

Dose / conc.:

0 mg/kg bw/day (nominal)

Remarks:

vehicle

Dose / conc.:

100 mg/kg bw/day (nominal)

Dose / conc.:

300 mg/kg bw/day (nominal)

Dose / conc.:

1 000 mg/kg bw/day (nominal)

Clinical signs:

no effects observed

Dermal irritation (if dermal study):

not examined

Mortality:

no mortality observed

Body weight and weight changes:

no effects observed

Description (incidence and severity):

No statistical significant difference from controls.

Food consumption and compound intake (if feeding study):

no effects observed

Description (incidence and severity):

No statistical significant difference from controls.

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Behaviour (functional findings):

not examined

Immunological findings:

not examined

Organ weight findings including organ / body weight ratios:

no effects observed

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Description (incidence and severity):

Slightly reduced numbers of spermatocytes and spermatids in 2/12 and 11/12 animals given 300 and 1000 mg/kg/day tris(2-ethylhexyl) benzene-1,2,4-tricarboxylaterespectively and a moderate decrease in 1/12 animals given 1000 mg/kg/day tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate. At this animal, a few multinucleate giant cell were appeared and slightly vacuolization of sertoli sells were observed. Also, at the epididymis, moderate amount of cell debris moderate decrease of spermatids and slightly granuloma of spermatic were observed. In addition the number of cells/number of spermatids in seminiferous tubules was reduced in males given 300 mg/kg/day tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate in stages I-VI. In males given 1000 mg/kg/day in stage I-IV numbers of spermatocytes and spermatids were reduced. In stages VII-XIV spermatocyte and spermatid numbers continued to be low and the sertolicell ratio was also reduced.

For the control group, atrophy of seminiferous tubule were observed 2 animals. At these animals, slightly amount of cell debris were observed. one of these animals, slight decrease of spermatids was also observed.

For females:
Cyst of corpus luteum of ovary was observed 2 animals of 300 mg/kg dosing group. No abnormal ovary observed at the female of 100 mg/kg dosing without successful copulation, females of control and 100 mg/kg dosing without pregnant.

Histopathological findings: neoplastic:

not examined

Other effects:

not examined

Reproductive function: oestrous cycle:

no effects observed

Description (incidence and severity):

No statistical significant difference from controls.

Reproductive function: sperm measures:

effects observed, treatment-related

Reproductive performance:

no effects observed

Key result

Dose descriptor:

NOEL

Effect level:

100 mg/kg bw/day

Based on:

test mat.

Sex:

male

Basis for effect level:

histopathology: non-neoplastic

Key result

Dose descriptor:

NOEL

Effect level:

1 000 mg/kg bw/day

Based on:

test mat.

Sex:

female

Basis for effect level:

other: see 'Remark'

Clinical signs:

no effects observed

Mortality / viability:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Description (incidence and severity):

Body weight and body weight gain in pups from the 300 mg/kg/day group were slightly low. However as the body weight and body weight gain in the 100 and 1000 mg/kg/day groups were unaffected this was not considered to be a definite effect of treatment.

Food consumption and compound intake (if feeding study):

not examined

Food efficiency:

not examined

Ophthalmological findings:

not examined

Haematological findings:

not examined

Clinical biochemistry findings:

not examined

Urinalysis findings:

not examined

Sexual maturation:

not examined

Organ weight findings including organ / body weight ratios:

not examined

Gross pathological findings:

no effects observed

Histopathological findings:

no effects observed

Other effects:

not examined

Behaviour (functional findings):

not examined

Developmental immunotoxicity:

not examined

Key result

Dose descriptor:

NOEL

Generation:

F1

Effect level:

1 000 mg/kg bw/day

Based on:

test mat.

Sex:

male/female

Basis for effect level:

other: see 'Remark'

Reproductive effects observed:

not specified

Conclusions:

Repeat dose toxicity: Histopathological examination revealed reduced spermatocytes and spermatids in the testes of males given tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate at doses of 300 and 1000 mg/kg/day. Treatment with tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate had no effect on the appearance, condition or behaviour, body weight, food consumption, necropsy findings, weights of the testes, epididymis or ovaries, or histopathology of the ovaries. The NOELs are considered to be 100 and 1000 mg/kg/day for males and females respectively.

Reproductive and developmental toxicity: With the exception of the effects in male described above treatment with tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate at dosages of 100, 300 or 1000 mg/kg/day had no effect on reproductive ability, organ weight or histopathology of the ovary, delivery or maternal behaviour of the dams. The NOELs are considered to be 100 and 1000 mg/kg/day for males and females respectively.

Pup post natal development: No effects of treatment with tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate at dosages of 100, 300 or 1000 mg/kg/day were detected on viability, general appearance, body weights or autopsy findings. The NOEL is considered to be 1000 mg/kg/day for males and female offspring.

These results can be considered the same for the target substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate.

Executive summary:

An OECD reproductive/developmental toxicity screening test [TG 421] was performed (MHWJapan, 1998) in compliance with GLP criteria and this study was identified to have been well conducted and reported. The study was performed with the read-across source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate.

A gavage study in SD rats was conducted at doses of 100, 300 and 1,000 mg/kg/day (male: 46 days,female: from 14 days before mating to day 3 of lactation) of the source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate.

Histopathological examination revealed decreased spermatocytes and spermatids in the testes of males given the substance at doses of 300 or 1000 mg/kg/day. Treatment had no effect on the appearance, body weight, food consumption, necropsy findings, weights of the testes, epididymis or ovaries, or histopathology of the ovaries. On the basis of these findings, the NOELs for systemic toxicity are considered to be 100 and 1000 mg/kg/day for males and females respectively.

With the exception of the effects in malesobserved on histopathological examination, treatment at dosages of 100, 300 and 1000 mg/kg/day had no effect on reproductive ability, organ weight or histopathological appearance of the ovaries, delivery or maternal behaviour of the dams.No effect of tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate was detected on viability, general appearance, body weight or autopsy findings of offspring. Body weight gain of pups at 300 mg/kg bw/day was slightly low, but body weights of all pups at 100 and 1000 mg/kg bw/day were not statistically different form control. On the basis of these findings, the NOELs for reproductive / developmental toxicity were considered to be 100mg/kg bw/day for male rats, 1,000 mg/kg bw/day for female rats, and 1,000 mg/kg bw/day for offspring.

This can be similarly transferred to the target substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, due to strong structural analogies

Effect on fertility: via oral route

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

NOAEL

100 mg/kg bw/day

Study duration:

subacute

Species:

rat

Quality of whole database:

Good quality due to guideline studies with good documentation.

Effect on fertility: via inhalation route

Endpoint conclusion:

no study available

Effect on fertility: via dermal route

Endpoint conclusion:

no study available

Additional information

In the key GLP compliant OECD 421 screening study of reproductive toxicity (MHW Japan, 1998) with the source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate in rats histopathological examination revealed reduced spermatocytes and spermatids in the testes of males given the substance at doses of 300 or 1000 mg/kg/day. Treatment had no effect on the appearance, body weight, food consumption, necropsy findings, weights of the testes, epididymis or ovaries, or histopathology of the ovaries. The NOELs for systemic toxicity are considered to be 100 and 1000 mg/kg/day for males and females respectively.

With the exception of the effects in males, treatment at dosages of 100, 300 and 1000 mg/kg/day had no effect on reproductive ability, organ weight or histopathology of the ovary, delivery or maternal behaviour of the dams. The NOEL for reproductive / developmental toxicity is considered to be 1000 mg/kg/day for offspring.

In a supporting repeated-dose toxicity combined with a screening study of reproductive toxicity (MHW Japan, 2001) according to OECD Guideline 422 and GLP criteria on the structural analogue trioctyl benzene-1,2,4-tricarboxylate no significant effect on reproductive ability, organ weight or histopathology of the ovary, delivery or maternal behaviour was apparent. The NOEL for reproductive / developmental toxicity is considered to be 500 mg/kg/day for both parents and offspring, the highest dose level examined.

This can be similarly transferred to the target substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, due to strong structural analogies

Short description of key information:
Fertility - Rat: NO(A)EL - Males - 100 mg/kg/day; Females - 1000 mg/kg/day

Effects on developmental toxicity

Effect on developmental toxicity: via oral route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via inhalation route

Endpoint conclusion:

no study available

Effect on developmental toxicity: via dermal route

Endpoint conclusion:

no study available

Justification for classification or non-classification

An OECD 421 screening study of reproductive toxicity (MHW Japan, 1998) with the read-across source substance tris(2-ethylhexyl) benzene-1,2,4-tricarboxylate with CAS No 3319-31-1 revealed no functional changes in fertility or reproductive performance although histopathological examination revealed reduced spermatocytes and spermatids in the testes of males given the substance at doses of 300 or 1000 mg/kg/day. This outcome is supported by MHW Japan, 2001 OECD 422 study (cobined Repeated Dose Toxicity Study with the Reproduction / Developmental toxicity Screening Test) on another structural analogue trioctyl benzene-1,2,4-tricarboxylate (CAS 89-04-3). Treatment with the substance had no significant effects on reproductive and developmental toxicity. The NOELs are considered to be 500 mg/kg/day for both reproductive toxicity and developmental toxicity. No effects of treatment with trioctyl benzene-1,2,4-tricarboxylate at dosages of 100, 300 or 1000 mg/kg/day were detected on viability, general appearance, body weights or autopsy findings of pup post natal development. The NOEL is considered to be 1000 mg/kg/day for males and female offspring.

This can be similarly transferred to the target substance tetrakis(2-ethylhexyl) benzene-1,2,4,5-tetracarboxylate, due to strong structural analogies

In accordance with Regulation (EC) No 1272/2008 effects such as small changes in semen parameters are considered to be of low or minimal toxicological significance insufficient to warrant classification.