Reaction mass of m-terphenyl and o-terphenyl

Endpoint summary

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

Read Across from terphenyl (CAS 26140 -60 -3) more specifically a Mixture or terphenyls and quarterphenyls; Key study: Genetic toxicity in vitro, Ames test (equivalent of similar to OECD 471) negative without metabolic activation for TA98, TA100, TA1535 and TA1537; negative with metabolic activation for strain TA98, TA1535 and TA 1537; positive with metabolic activation only for strain TA100, overall results equivocal

Read Across from terphenyl (CAS 26140 -60 -3) more specifically a Mixture or terphenyls and quarterphenyls; Supporting study: genetic toxicity in vitro, Ames test (according to Ames et al., 1975), negative

Read Across from terphenyl (CAS 26140 -60 -3) more specifically a Mixture or terphenyls and quarterphenyls; Supporting study: genetic toxicity in vitro, Ames test (according to Ames et al., 1975), negative

Read Across from terphenyl (CAS 26140 -60 -3) more specifically a Mixture or terphenyls and quarterphenyls; Key study: Genetic toxicity in vitro, Chromosome Aberration (OECD 473), negative

Read Across from terphenyl (CAS 26140 -60 -3) more specifically a Mixture or terphenyls and quarterphenyls; Key study: Genetic toxicity in vitro, In Vitro Mammalian Cell Gene Mutation Test (OECD 476), negative

Read Across from terphenyl (CAS 26140 -60 -3) more specifically a Mixture or terphenyls and quarterphenyls; Supporting study: Genetic toxicity in vitro, In Vitro Mammalian Cell Gene Mutation Test (OECD 476), negative

Link to relevant study records

Reference

Reference 1

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

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
In this justification, the read-across (bridging) concept is applied, based on the chemical structure of the potential analogues, their toxicokinetic behaviour and other available (eco-)toxicological data.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance terphenyl (containing mainly m-terphenyl, o-terphenyl and only little p-terphenyl as well as a low percentage of quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups. Obviously, the contained isomers are only different to a minor extent. Moreover, all isomers have common functional group(s). In addition, they were simulated to have the same breakdown products using the In vivo rat metabolism simulator and the Rat liver S9 metabolism simulator (OECD QSAR Toolbox v4.2).
Therefore both substances are expected to follow the same toxicokinetic pattern.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

source substance:
Mixture of terphenyls (ca. 60 %; mainly m- and o-terphenyls and only a minor content of p-terphenyl) and quarterphenyls (ca. 35 %)
structural formula: C18H14 and C24H18
The terphenyl substance consists of three constituents, each with their own Smiles notation and structural formula:
o-terphenyl: c(c(c(cccc1)c1)ccc2)(c(cccc3)c3)c2
m-terphenyl: c(c(cccc1)c1)(cccc2c(cccc3)c3)c2
p-terphenyl: c(c(cccc1)c1)(ccc(c(cccc2)c2)c3)c3
The quarterphenyls:
ortho-/ortho-:c1cccc(c1c1ccccc1)c1ccccc1c1ccccc1
ortho-/meta-: c1c(cccc1c1ccccc1c1ccccc1)c1ccccc1
ortho-/para-: c1cc(ccc1c1ccccc1)c1ccccc1c1ccccc1
meta-/meta-: c1c(cccc1c1cccc(c1)c1ccccc1)c1ccccc1
meta-/para-: c1cc(ccc1c1ccccc1)c1cccc(c1)c1ccccc1
para-/para-: c1cc(ccc1c1ccccc1)c1ccc(cc1)c1ccccc1
CAS 26140-60-3
EC No 247-477-3
purity: not specified

target substance:
Reaction mass of m-terphenyl and o-terphenyl (100 % m- and o-terphenyl)
structural formula: C18H14
The substance consists of two constituents, each with their own Smiles notation and structural formula:
o-terphenyl: c(c(c(cccc1)c1)ccc2)(c(cccc3)c3)c2
m-terphenyl: c(c(cccc1)c1)(cccc2c(cccc3)c3)c2
CAS -
EC No 904-797-4
purity: ≥ 90 - ≤ 100 % (w/w)

3. ANALOGUE APPROACH JUSTIFICATION
Reaction mass of m-terphenyl and o-terphenyl and Mixture of terphenyls (ca. 60 %) and quarterphenyls (ca. 35 %) belong to the group of closely related aromatic hydrocarbons. Terphenyls, also known as diphenylbenzenes or triphenyls, consist of a central benzene ring substituted with two phenyl groups.

Both chemicals are expected to be metabolised similarly building similar metabolites (“common breakdown product").
The similar findings (refer to data matrix outlined below) for both substances support the conclusion that similar molecules will be formed from both substances when applied systemically. In consequence, Mixture of terphenyls and quarterphenyls may perfectly serve as read-across substance for Reaction mass of m-terphenyl and o-terphenyl and vice versa. So, the available data on Mixture of terphenyls and quarterphenyls can be used to cover all systemic endpoints currently lacking from Reaction mass of m-terphenyl and o-terphenyl, making further testing obsolete.

4. DATA MATRIX
There is mainly physico-chemical data available on the toxicological properties of Reaction mass of m-terphenyl and o-terphenyl. Data on Mixture of terphenyls and quarterphenyls covers among others the toxicokinetic, acute toxicity, irritation / corrosion and genetic mutation in vitro endpoint. The identification and discussion of common properties will be based on available data including toxicological and physicochemical data.
The physical state of the two substances is solid (Reaction Mass of m-terphenyl and o-terphenyl is a cream coloured solid block at room temperature; Mixture of terphenyls and quarterphenyls is a soft solid at room temperature, melting to a yellow liquid). Their melting point lies at 32 °C and 145 °C; their boiling point at 355°C and 343°C. Furthermore, their density is quite similar (1.11 x 10E3 kg/m3 at 20.0 ± 0.5 ºC and 1.133 x 10E3 kg/m3 at 25 ºC) and the vapour pressure is also in the same range (1.8 x 10E-2 Pa at 25 °C (corresponding to 1.7765 x 10E-7 atmosphere) and 1.6x10-5to 3.0x10E-14 atmosphere; the estimated vapour pressure of the o-, m- and p-terphenyls ranged from 4.3 x 10E-7 to 8.0 x 10E-10 atmosphere.
The available data for the following physico-chemical properties, which are relevant for absorption into living organisms, are very similar. Both substances are medium sized molecules with a molecular weight of 230.31 (Reaction mass of m-terphenyl and o-terphenyl) resp. 230 and 306 (terphenyls and quarterphenyls), they are both insoluble and slightly soluble in water (Less than 1.0 x 10E-4 g/L of solution at 20.0 ± 0.5 °C (Reaction mass of m-terphenyl and o-terphenyl) and 0.151 mg/L at 25°C (Mixture of terphenyls and quarterphenyls), respectively). Moreover, they have a rather high logPow (3.01 to 5.94 (Reaction mass of m-terphenyl and o-terphenyl) and 5.86 at 22°C (Mixture of terphenyls and quarterphenyls)). Both chemicals are not readily biodegradable and they are not expected to be hydrolysed due to lack of functional groups. For Reaction mass of m-terphenyl and o-terphenyl a QSAR calculation on the bioconcentration factor (BCF) has been performed. For both - m-terphenyl and o-terphenyl - a BCF of 2041 L/kg wet-wt (3.31 log BCF) was predicted. Mixture of terphenyls and quarterphenyls has a low potential for bioaccumulation in aquatic organisms.

There is only data available for the target substance Reaction mass of m-terphenyl and o-terphenyl for the following toxicological endpoints: Repeated dose toxicity oral and Toxicity to reproduction (fertility / developmental toxicity).
Moreover, there is data available for the Read Across substance Mixture of terphenyls and quarterphenyls for the following endpoints: Acute toxicity oral, Acute toxicity dermal, Skin irritation / corrosion, Eye irritation /corrosion, Genetic toxicity in vitro.
The Read Across substance Mixture or terphenyls and quarterphenyls has been shown to be not acutely toxic and not irritating to the skin or the eyes. In addition, the Read Across substance has been shown to be not mutagenic. For Reaction mass of m-terphenyl and o-terphenyl a NOAEL of 100 mg/kg bw was derived for the endpoint Repeated dose toxicity oral and for reproduction / developmental toxicity, based on effects around parturition at 300 mg/kg/day.

Reason / purpose for cross-reference:

read-across source

Species / strain:

S. typhimurium TA 1535

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 100

Metabolic activation:

with

Genotoxicity:

positive

Remarks:

between 10-0.04 mg

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 1537

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 98

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Species / strain:

S. typhimurium TA 100

Metabolic activation:

without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

not specified

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Water solubility: not soluble in water
- Precipitation: sample precipitates out on plates at 10, 3 and 1 mg/plate

ADDITIONAL INFORMATION ON CYTOTOXICITY:
In the toxicity screen, a concentration of > or = 1mg of sample per plate expressed a slight level of toxicity in the presence and absence of microsomal activation.

The plate incorporation assay: Summary

With microsomal activation
Amount/plate (mg)	Revertants/plate
	TA98			TA100			TA1535			TA1537
10.0	42	32	40	138	170	128	10	10	10	9	7	6
3.0	50	35	35	124	154	144	10	7	8	3	6	6
1.0	37	49	43	107	128	124	12	18	14	7	6	5
0.2	46	34	38	128	123	133	16	8	13	10	2	6
0.04	45	47	38	132	126	125	16	9	14	8	7	10
0.01	41	35	33	99	99	81	5	15	8	5	10	4
Controls
Solvent	29	39	38	119	84	81	14	10	12	10	11	11
Negative	45			75			6			8
Positive		861			1159			280			342

   

Without microsomal activation
Amount/plate (mg)	Revertants/plate
	TA98			TA100			TA1535			TA1537
10.0	25	28	28	97	74	73	12	4	12	8	5	4
3.0	27	20	34	77	83	86	5	11	9	5	5	7
1.0	25	29	31	69	60	93	12	7	11	8	6	4
0.2	27	24	30	97	50	58	8	9	6	12	10	5
0.04	27	29	35	78	74	61	11	16	6	12	9	4
0.01	28	30	26	74	77	68	7	5	6	7	6	7
Controls
Solvent	29	27	29	89	63	79	8	8	7	11	19	8
Negative	28			91			14			8
Positive		667			1174			535			1564

Conclusions:

Interpretation of results: equivocal (overall result).
Individual results: negative without metabolic activation for TA98, TA100, TA1535 and TA1537; negative with metabolic activation for strain TA98, TA1535 and TA 1537; positive with metabolic activation only for strain TA100.
The Ames test indicated that there was no activation without metabolic activation. With metabolic activation, one strain showed positive results (TA100) while all other strains were negative. However, this single positive result in TA100 has to be judged carefully when taking a closer look at the mean values of the plates of TA100+S9: 93/ 128 / 128 / 120 / 141 / 145 revertants per plate (solvent: 95 revertants/plate). As such, the test item showed only a slight increase by a factor of 1.5 which can not clearly be judged as biologically relevant (an increase of more than 12 times was found for the positive control). A report of the U.S. Environmental Protection Agency Gene-Tox-Program (Kier et al., 1986, [1]) points out that a biologically relevant increase in tester strain TA100 requires the number of reversions to be at least twice as high. As such, taking into account the information given in the guidance on the application of the CLP criteria and in the publication of Kier et. al, 1986, the obtained results do not allow for a clear derivation of a positive result and are considered as equivocal and questionable.
[1] Kier, L.E., Brusick, D.J., Auletta, A.E., von Halle, E.S., Brown, M.M., Simmon, V.F., Dunkel, V., McCann, J., Mortelmans, K., Prival, M., Rao, T.K. and Ray, V. (1986), The Salmonella typhimurium/mammalian microsomal assay. A report of the U.S. Environmental Protection Agency Gene-Tox–Program, Mutat. Res. 168, 69-240

The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance biphenyl-2-ol used in this study belong to the group of closely related aromatic hydrocarbons. Also known as phenylbenzenes / diphenylbenzenes or biphenyls/ triphenyls, they consist of a central benzene ring substituted with one/ two phenyl groups.
Therefore both substances are expected to follow the same toxicokinetic pattern. For the detailed procedure of the read-across principle and justifications, please refer to the analogue approach justification depicted above.

Executive summary:

Mixture of terphenyls and quarterphenyls was not mutagenic with and without metabolic activation in Salmonella strains TA98, TA1535 and TA1537. The Mixture of terphenyls and quarterphenyls was not mutagenic without metabolic activation in Salmonella strain TA100. The experiments with the Mixture of terphenyls and quarterphenyls with metabolic activation revealed equivocal results in Salmonella strain TA100. A slight increase of the number of revertants per plate (factor of 1.5) was observed. However, this single positive result in TA100 has to be judged carefully when taking a closer look at the mean values of the plates of TA100+S9: 93/ 128 / 128 / 120 / 141 / 145 revertants per plate (solvent: 95 revertants/plate). As such, the Mixture of terphenyls and quarterphenyls showed only a slight increase by a factor of 1.5 which can not clearly be judged as biologically relevant (an increase of more than 12 times was found for the positive control). A report of the U.S. Environmental Protection Agency Gene-Tox-Program (Kier et al., 1986, [1]) points out that a biologically relevant increase in tester strain TA100 requires the number of reversions to be at least twice as high. As such, taking into account the information given in the guidance on the application of the CLP criteria, the obtained results do not allow for a clear derivation of a positive result and are considered as equivocal and questionable.

[1] Kier, L.E., Brusick, D.J., Auletta, A.E., von Halle, E.S., Brown, M.M., Simmon, V.F., Dunkel, V., McCann, J., Mortelmans, K., Prival, M., Rao, T.K. and Ray, V. (1986), The Salmonella typhimurium/mammalian microsomal assay. A report of the U.S. Environmental Protection Agency Gene-Tox–Program, Mutat. Res. 168, 69-240

The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance biphenyl-2-ol used in this study belong to the group of closely related aromatic hydrocarbons. Also known as phenylbenzenes / diphenylbenzenes or biphenyls/ triphenyls, they consist of a central benzene ring substituted with one/ two phenyl groups.

Therefore both substances are expected to follow the same toxicokinetic pattern. For the detailed procedure of the read-across principle and justifications, please refer to the analogue approach justification depicted above.

Reference 2

Endpoint:

in vitro cytogenicity / chromosome aberration study in mammalian cells

Remarks:

Type of genotoxicity: chromosome aberration

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
In this justification, the read-across (bridging) concept is applied, based on the chemical structure of the potential analogues, their toxicokinetic behaviour and other available (eco-)toxicological data.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance terphenyl (containing mainly m-terphenyl, p-terphenyl and only little o-terphenyl as well as a low percentage of quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups. Obviously, the contained isomers are only different to a minor extent. Moreover, all isomers have common functional group(s). In addition, they were simulated to have the same breakdown products using the In vivo rat metabolism simulator and the Rat liver S9 metabolism simulator (OECD QSAR Toolbox v4.2).
Therefore both substances are expected to follow the same toxicokinetic pattern.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

source substance:
Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls (< 25 %)
structural formula: C18H14 and C24H18
The terphenyl substance consists of three constituents, each with their own Smiles notation and structural formula:
o-terphenyl: c(c(c(cccc1)c1)ccc2)(c(cccc3)c3)c2
m-terphenyl: c(c(cccc1)c1)(cccc2c(cccc3)c3)c2
p-terphenyl: c(c(cccc1)c1)(ccc(c(cccc2)c2)c3)c3
The quarterphenyls:
ortho-/ortho-:c1cccc(c1c1ccccc1)c1ccccc1c1ccccc1
ortho-/meta-: c1c(cccc1c1ccccc1c1ccccc1)c1ccccc1
ortho-/para-: c1cc(ccc1c1ccccc1)c1ccccc1c1ccccc1
meta-/meta-: c1c(cccc1c1cccc(c1)c1ccccc1)c1ccccc1
meta-/para-: c1cc(ccc1c1ccccc1)c1cccc(c1)c1ccccc1
para-/para-: c1cc(ccc1c1ccccc1)c1ccc(cc1)c1ccccc1
CAS 26140-60-3
EC No 247-477-3
purity: not specified

target substance:
Reaction mass of m-terphenyl and o-terphenyl (100 % m- and o-terphenyl)
structural formula: C18H14
The substance consists of two constituents, each with their own Smiles notation and structural formula:
o-terphenyl: c(c(c(cccc1)c1)ccc2)(c(cccc3)c3)c2
m-terphenyl: c(c(cccc1)c1)(cccc2c(cccc3)c3)c2
CAS -
EC No 904-797-4
purity: ≥ 90 - ≤ 100 % (w/w)

3. ANALOGUE APPROACH JUSTIFICATION
Reaction mass of m-terphenyl and o-terphenyl and Mixture of terphenyls and quarterphenyls (< 25 %) belong to the group of closely related aromatic hydrocarbons. Terphenyls, also known as diphenylbenzenes or triphenyls, consist of a central benzene ring substituted with two phenyl groups.

Both chemicals are expected to be metabolised similarly building similar metabolites (“common breakdown product").
The similar findings (refer to data matrix outlined below) for both substances support the conclusion that similar molecules will be formed from both substances when applied systemically. In consequence, Mixture of terphenyls and quarterphenyls may perfectly serve as read-across substance for Reaction mass of m-terphenyl and o-terphenyl and vice versa. So, the available data on Mixture of terphenyls and quarterphenyls can be used to cover all systemic endpoints currently lacking from Reaction mass of m-terphenyl and o-terphenyl, making further testing obsolete.

4. DATA MATRIX
There is mainly physico-chemical data available on the toxicological properties of Reaction mass of m-terphenyl and o-terphenyl. Data on Mixture of terphenyls and quarterphenyls covers the genetic mutation in vitro endpoint. The identification and discussion of common properties will be based on available data including toxicological and physicochemical data.
The physical state of the two substances is solid (Reaction Mass of m-terphenyl and o-terphenyl is a cream coloured solid block at room temperature; Mixture of terphenyls and quarterphenyls is a solid at room temperature). Their melting point lies at 32 °C and 145 °C; their boiling point at 355°C and 343°C. Furthermore, their density is quite similar (1.11 x 10E3 kg/m3 at 20.0 ± 0.5 ºC and 1.041 x 10E3 kg/m3 at 25 ºC) and the vapour pressure is expected to be in the same range ((1.8 x 10E-2 Pa at 25 °C, corresponding to 1.7765 x 10E-7 atmosphere for Reaction mass of m-terphenyl and o-terphenyl); the estimated vapour pressure of the o-, m- and p-terphenyls ranged from 4.3 x 10E-7 to 8.0 x 10E-10 atmosphere).
The available data for the following physico-chemical properties, which are relevant for absorption into living organisms, are very similar. Both substances are medium sized molecules with a molecular weight of 230.31 (Reaction mass of m-terphenyl and o-terphenyl) resp. 230 and 306 (terphenyls and quarterphenyls), they are both either insoluble and slightly soluble in water ((Less than 1.0 x 10E-4 g/L of solution at 20.0 ± 0.5 °C (Reaction mass of m-terphenyl and o-terphenyl) and 0.151 mg/L at 25°C (Mixture of terphenyls and quarterphenyls), respectively). Moreover, they have a rather high logPow (3.01 to 5.94 (Reaction mass of m-terphenyl and o-terphenyl) and 5.86 at 22°C (Mixture of terphenyls and quarterphenyls)). Both chemicals are not readily biodegradable and they are not expected to be hydrolysed due to lack of functional groups. For Reaction mass of m-terphenyl and o-terphenyl a QSAR calculation has been performed for the bioconcentration factor (BCF). For both - m-terphenyl and o-terphenyl - a BCF of 2041 L/kg wet-wt (3.31 log BCF) was predicted. Mixture of terphenyls and quarterphenyls has a low potential for bioaccumulation in aquatic organisms.

There is only data available for the target substance Reaction mass of m-terphenyl and o-terphenyl for the following toxicological endpoints: Repeated dose toxicity oral and Toxicity to reproduction (fertility / developmental toxicity).
Moreover, there is data available for the Read Across substance Mixture of terphenyls and quarterphenyls for the following endpoints: Genetic toxicity in vitro.
The Read Across substance Mixture or terphenyls and quarterphenyls has been shown to be not mutagenic. For Reaction mass of m-terphenyl and o-terphenyl a NOAEL of 100 mg/kg bw was derived for the endpoint Repeated dose toxicity oral and for reproduction / developmental toxicity, based on effects around parturition at 300 mg/kg/day.

Reason / purpose for cross-reference:

read-across source

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Vehicle controls validity:

not valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Solubility: the Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls was insoluble in acetone above 150 µg/mL

ADDITIONAL INFORMATION ON CYTOTOXICITY:
Preliminary cytotoxicity studies were conducted both with and without metabolic activation at Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls concentrations of 9.4, 18.8, 37.5, 75.0, and 150.0 µg/mL.
A statistically significant decrease in MI and in the percentage of M2 cells were noted for cells treated with 150 µg/mL and significant decreases in the percentage of M2 metaphase cells were noted at Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls R concentrations of 18.8 µglmL and above, with and without metabolic activation, respectively.
From these findings, Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls concentrations of 37.5, 75.0, and 150.0 µg/mL were chosen for the cytogenetic assay.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Cytogenetic Evaluation Of CHO Cells Exposed To Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls In The Absence Of Exogenous Metabolic Activation

	8-10 hour harvest		24-26 hour harvest
	Solvent control (1% Acetone)	Positive control (110 µg/mlMMS)	Solvent control (1% Acetone)	37.5 µg/mL Mixed Terphenyls and Quarterphenyls	75.0 µg/mL Mixed Terphenyls and Quarterphenyls	150.0 µg/mL Mixed Terphenyls and Quarterphenyls
Mitotic index (%)	4.4	1.2	3.5	2.1	1.7	2.5
Number of cells analyzed	100	100	100	100	100	100
Number (%) aberrant cells	3 (3.0)	98 (98.0)	2 (2.0)	1 (1.0)	2 (2.0)	1 (1.0)
Number (%) cells with structurally abnormal chromosomes*	2 (2.0)	97 (97.0)*	2 (2.0)	1 (1.0)	1 (1.0)	0
Number (%) cells with:
Chromosome deletions	0	0	0	0	0	0
Chromosome exchanges	0	0	0	0	0	0
Chromatid deletions	2 (2.0)	33 (91.7)	2 (2.0)	1 (1.0)	1 (1.0)	0
Chromatid exchanges	0	2 (5.6)	0	0	0	0
Polyploidy	1 (1.0)	1 (2.8)	0	0	1 (1.0)	1 (1.0)
Severe damage	0	64 (64.0)	0	0	0	0
Number (frequency/cell) of aberrations:
Overall aberrations	3 (0.03)	407 (4.07)	2 (0.02)	1 (0.01)	2 (0.02)	1 (0.01)
Structural aberrations*	2 (0.02)	406 (4.06)*	2 (0.02)	1 (0.01)	1 (0.01)	0
Chromosome deletions	0	0	0	0	0	0
Chromosome exchanges	0	0	0	0	0	0
Chromatid deletions	2 (0.02)	84 (2.33)	2 (0.02)	1 (0.01)	1 (0.01)	0
Chromatid exchanges	0	2 (0.06)	0	0	0	0
Number (%) cells with:
Chromatid gaps	14 (14.0)	20 (55.6)	3 (3.0)	3 (3.0)	3 (3.0)	1 (1.0)
Isochromatid gaps	7 (7.0)	2 (5.6)	2 (2.0)	3 (3.0)	0	5 (5.0)

*No significant differences were noted among the solvent control and Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls-treated cells. The positive control was significantly higher than the solvent control (p > 0.0001).

Cytogenetic Evaluation Of CHO Cells Exposed To Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls In The Presence Of Exogenous Metabolic Activation (8 -10 Hour Harvest)

	Solvent control (1% Acetone)	37.5 µg/mL Mixed terphenyls and Quarterphenyls	75.0 µg/mL Mixed Terphenyls and Quarterphenyls	150.0 µg/mL Mixed terphenyls and Quarterphenyls	Positive control (110 µg/mL CP)
Mitotic index (%)	3.3	4.2	6.2	2.4	0.5
Number of cells analyzed	100	100	100	100	100
Number (%) aberrant cells	0	2 (2.0)	4 (4.0)	5 (5.0)	19 (19.0)
Number (%) cells with structurally abnormal chromosomes*	0	2 (2.0)	4 (4.0)	5 (5.0)	19 (19.0)*
Number (%) cells with:
Chromosome deletions	0	0	1 (1.0)	0	0
Chromosome exchanges	0	0	0	0	0
Chromatid deletions	0	2 (2.0)	3 (3.0)	5 (5.0)	17 (17.2)
Chromatid exchanges	0	0	0	0	1 (1.0)
Polyploidy	0	0	0	0	0
Severe damage	0	0	0	0	1 (1.0)
Number (frequency/cell) of aberrations:
Overall aberrations	0	3 (0.03)	4 (0.04)	5 (0.05)	32 (0.32)
Structural aberrations*	0	3 (0.03)	4 (0.04)	5 (0.05)	32 (0.32)*
Chromosome deletions	0	0	1 (0.01)	0	0
Chromosome exchanges	0	0	0	0	0
Chromatid deletions	0	3 (0.03)	3 (0.03)	5 (0.05)	26 (0.26)
Chromatid exchanges	0	0	0	0	1 (0.01)
Number (%) cells with:
Chromatid gaps	7 (7.0)	4 (4.0)	5 (5.0)	9 (9.0)	23 (23.2)
Isochromatid gaps	0	0	0	0	0

*No significant differences were noted among the solvent control and Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls-treated cells. The positive control was significantly higher than the solvent control (p > 0.05).

Conclusions:

Interpretation of results: negative
The chromosome aberration test showed no significant differences between the solvent control and the cells treated with the test substance. The test substance Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls is considered not to have clastogenic effects in CHO cells.
The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance mixed terphenyl (containing mainly m-terphenyl, p-terphenyl and only a mino content of o-terphenyl) and quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups.
Therefore both substances are expected to follow the same toxicokinetic pattern. For the detailed procedure of the read-across principle and justifications, please refer to the analogue approach justification depicted above.

Executive summary:

The ability of Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls to induce chromosomal aberrations (CA) in Chenise hamster ovary (CHO) cells both in the presence and in the absence of rat S9 metabolic activation (MA). In the definitive studies, CHO cells were exposed to Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls at concentrations of 37.5, 75 and 150 µg/mL in the absence of and in the presence of MA. The cells were then evaluated microscopically for mitotic indices and for chromosomal aberrations. Solvent and positive controls were included in the study. It was concluded that Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls does not induce chromosomal aberrations in the presence of in the absence of MA under the conditions used in this study.

The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance mixed terphenyl (containing mainly m-terphenyl, p-terphenyl and only a mino content of o-terphenyl) and quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups.

Therefore both substances are expected to follow the same toxicokinetic pattern. For the detailed procedure of the read-across principle and justifications, please refer to the analogue approach justification depicted above.

Reference 3

Endpoint:

in vitro gene mutation study in mammalian cells

Remarks:

Type of genotoxicity: gene mutation

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
In this justification, the read-across (bridging) concept is applied, based on the chemical structure of the potential analogues, their toxicokinetic behaviour and other available (eco-)toxicological data.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance terphenyl (containing mainly m-terphenyl, o-terphenyl and only little p-terphenyl as well as a low percentage of quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups. Obviously, the contained isomers are only different to a minor extent. Moreover, all isomers have common functional group(s). In addition, they were simulated to have the same breakdown products using the In vivo rat metabolism simulator and the Rat liver S9 metabolism simulator (OECD QSAR Toolbox v4.2).
Therefore, both substances are expected to follow the same toxicokinetic pattern.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

source substance:
Mixture of terphenyls (mainly m- and o-terphenyls and only a minor content of p-terphenyl) and quarterphenyls (ca. 25 %)
structural formula: C18H14 and C24H18
The terphenyl substance consists of three constituents, each with their own Smiles notation and structural formula:
o-terphenyl: c(c(c(cccc1)c1)ccc2)(c(cccc3)c3)c2
m-terphenyl: c(c(cccc1)c1)(cccc2c(cccc3)c3)c2
p-terphenyl: c(c(cccc1)c1)(ccc(c(cccc2)c2)c3)c3
The quarterphenyls:
ortho-/ortho-:c1cccc(c1c1ccccc1)c1ccccc1c1ccccc1
ortho-/meta-: c1c(cccc1c1ccccc1c1ccccc1)c1ccccc1
ortho-/para-: c1cc(ccc1c1ccccc1)c1ccccc1c1ccccc1
meta-/meta-: c1c(cccc1c1cccc(c1)c1ccccc1)c1ccccc1
meta-/para-: c1cc(ccc1c1ccccc1)c1cccc(c1)c1ccccc1
para-/para-: c1cc(ccc1c1ccccc1)c1ccc(cc1)c1ccccc1
CAS 26140-60-3
EC No 247-477-3
purity: not specified

target substance:
Reaction mass of m-terphenyl and o-terphenyl (100 % m- and o-terphenyl)
structural formula: C18H14
The substance consists of two constituents, each with their own Smiles notation and structural formula:
o-terphenyl: c(c(c(cccc1)c1)ccc2)(c(cccc3)c3)c2
m-terphenyl: c(c(cccc1)c1)(cccc2c(cccc3)c3)c2
CAS -
EC No 904-797-4
purity: ≥ 90 - ≤ 100 % (w/w)

3. ANALOGUE APPROACH JUSTIFICATION
Reaction mass of m-terphenyl and o-terphenyl and Mixture of terphenyls and quarterphenyls (ca. 25 %) belong to the group of closely related aromatic hydrocarbons. Terphenyls, also known as diphenylbenzenes or triphenyls, consist of a central benzene ring substituted with two phenyl groups.

Both chemicals are expected to be metabolised similarly building similar metabolites (“common breakdown product").
The similar findings (refer to data matrix outlined below) for both substances support the conclusion that similar molecules will be formed from both substances when applied systemically. In consequence, Mixture of terphenyls and quarterphenyls may perfectly serve as read-across substance for Reaction mass of m-terphenyl and o-terphenyl and vice versa. So, the available data on Mixture of terphenyls and quarterphenyls can be used to cover all systemic endpoints currently lacking from Reaction mass of m-terphenyl and o-terphenyl, making further testing obsolete.

4. DATA MATRIX
There is mainly physico-chemical data available on the toxicological properties of Reaction mass of m-terphenyl and o-terphenyl. Data on Mixture of terphenyls and quarterphenyls covers the acute toxicity to inhalation endpoint and genetic mutation in vitro and in vivo endpoint. The identification and discussion of common properties will be based on available data including toxicological and physicochemical data.
The physical state of the two substances is solid (Reaction Mass of m-terphenyl and o-terphenyl is a cream coloured solid block at room temperature; Mixture of terphenyls and quarterphenyl is a soft solid melting to yellow liquid at room temperature). Their melting point lies at 32 °C and 40-70 °C; their boiling point at 355°C and approximately 400 °C. Furthermore, their density is quite similar (1.11 x 10E3 kg/m3 at 20.0 ± 0.5 ºC and 1.041 x 10E3 kg/m3 at 25 ºC or 1.081 kg/m³ at 60°C) and the vapour pressure is expected to be in the same range (1.8 x 10E-2 Pa at 25 °C, corresponding to 1.7765 x 10E-7 atmosphere for Reaction mass of m-terphenyl and o-terphenyl and 11 mm Hg at 200°c for Mixture of terphenyls and quarterphenyls); the estimated vapour pressure of the o-, m- and p-terphenyls ranged from 4.3 x 10E-7 to 8.0 x 10E-10 atmosphere).
The available data for the following physico-chemical properties, which are relevant for absorption into living organisms, are very similar. Both substances are medium sized molecules with a molecular weight of 230.31 (Reaction mass of m-terphenyl and o-terphenyl) resp. 230 and 306 (terphenyls and quarterphenyls)), they are both either insoluble expected to be insoluble to slightly soluble in water ((Less than 1.0 x 10E-4 g/L of solution at 20.0 ± 0.5 °C (Reaction mass of m-terphenyl and o-terphenyl). Moreover, they have a rather high logPow (3.01 to 5.94 (Reaction mass of m-terphenyl and o-terphenyl) and 5.86 at 22°C (Mixture of terphenyls and quarterphenyls)). Both chemicals are not readily biodegradable and they are not expected to be hydrolysed due to lack of functional groups. For Reaction mass of m-terphenyl and o-terphenyl a QSAR calculation has been performed for the biocncentration factor (BCF). For both - m-terphenyl and o-terphenyl - a BCF of 2041 L/kg wet-wt (3.31 log BCF) was predicted. Mixture of terphenyls and quarterphenyls has a low potential for bioaccumulation in aquatic organisms.

There is only data available for the target substance Reaction mass of m-terphenyl and o-terphenyl for the following toxicological endpoints: Repeated dose toxicity oral and Toxicity to reproduction (fertility / developmental toxicity).
Moreover, there is data available for the Read Across substance Mixture of terphenyls and quarterphenyls for the following endpoints: Acute toxicity to inhalation, Genetic toxicity in vitro and Genetic toxicity in vivo.
The Read Across substance Mixture or terphenyls and quarterphenyls has been shown to be not mutagenic. For Reaction mass of m-terphenyl and o-terphenyl a NOAEL of 100 mg/kg bw was derived for the endpoint Repeated dose toxicity oral and for reproduction / developmental toxicity, based on effects around parturition at 300 mg/kg/day.

Reason / purpose for cross-reference:

read-across source

Species / strain:

Chinese hamster Ovary (CHO)

Metabolic activation:

with and without

Genotoxicity:

negative

Cytotoxicity / choice of top concentrations:

cytotoxicity

Vehicle controls validity:

valid

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

TEST-SPECIFIC CONFOUNDING FACTORS
- Precipitation: the Mixture of terphenyls and quarterphenyls precipitated out of solution at the 100, 333 and 1000 µg/mL dose levels when added to the treatment media.

RANGE-FINDING/SCREENING STUDIES:
The Mixture of terphenyls and quarterphenyls was evaluated in a Preliminary Mutagenicity Screen at dose levels of 20, 50 and 100 µg/mL of treatment volume at 0, 1, 2, 5 and 10% concentrations of metabolic activation preparation. Initial cell survivals from this assay were 60.6% to 76.4% without metabolic activation and 14.3% to 76.9%, 32.3% to 90.8%, 60.8% to 79.7% and 47.6% to 81% relative cell survival at the 1, 2, 5 and 10% S-9 concentrations, respectively. At these dose levels and S-9 concentrations, there were no statistically significant increases in the mutation frequencies observed in the treated cultures, however, regression analysis expressed the possibility of a dose dependent trend with the 10% S-9 concentration.

ADDITIONAL INFORMATION ON CYTOTOXICITY:
The Mixture of terphenyls and quarterphenyls was evaluated for cytotoxicity at 8 doses with 0.3, 1, 3.3, 10.0, 33.3, 100.0, 333.0 and 1000.0 µg/mL of media. All dose levels were tested in single replicate without and with metabolic activation at concentrations of 1%, 2%, 5% and 10% of the treatment volume.
Results without metabolic activation produced 67.4, 45.3 and 66.6% relative cell survival at the 100, 333 and 1000 µg/mL dose levels, respectively. With metabolic activation, the 333 µg/mL dose level was cytotoxic at all S-9 concentrations. However, at the 1000 µg/mL dose level, results showed a 69.9, 37.9, 44.0 and 42.4% relative cell survival at the 1, 2, 5 and 10% S-9 concentrations, respectively. This difference in cytotoxic effects at the 333 and 1000 µg/mL dose levels was due to the fact that at the 1000 µg/mL level the Mixture of terphenyls and quarterphenyls precipitation effectively resembled a clump of the Mixture of terphenyls and quarterphenyls which was non-misable in the test media, resulting in a very low effective dose, where as there was a good suspension of the precipitate at the 333 µg/mL dose level yielding a higher effective dose.

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Summary of triplicates mutagenicity data for control and treated cultures:

Compound	µg/mL			S-9 (+ or -)			Relative initial survival (%)			Total No. of mutants (5 plates)			Cloning efficiency (%)			Mutant frequency (Mutants/10^6clonable cells)			Mean mutation frequency
Untreated	-	-	-	-	-	-	98.1	95.0	106.8	3	5	1	82.5	75.7	86.7	3.6	6.6	1.2	3.8
Untreated	-	-	-	+10%	+10%	+10%	99.1	99.6	112.0	4	1	0	98.0	84.7	84.0	4.1	1.2	0.0	1.8
Acetone	5	5	5	-	-	-	107.07	99.8	89.7	9	5	11	99.8	89.2	84.3	9.0	5.6	13.0	9.2
Acetone	5	5	5	+10%	+10%	+10%	93.8	108.9	105.3	8	9	9	91.7	87.8	88.2	8.7	10.3	10.2	9.7
EMS	200	200	200	-	-	-	71.1	80.1	83.2	164	212	254	77.2	70.5	75.8	212.4	300.7	335.1	282.7
DMN	100	100	100	+10%	+10%	+10%	76.8	70.2	69.3	111	65	68	70.7	79.7	70.0	157.0	81.6	97.1	111.9
Mixture of terphenyls and quarterphenyls	5	5	5	-	-	-	104.7	112.8	87.8	10	3	2	82.7	90.0	85.8	12.1	3.3	2.3	5.9
Mixture of terphenyls and quarterphenyls	25	25	25	-	-	-	87.6	91.7	87.3	2	4	9	93.5	89.5	89.5	2.1	4.5	10.1	5.6
Mixture of terphenyls and quarterphenyls	50	50	50	-	-	-	78.9	78.6	63.7	8	2	0	90.7	90.3	95.3	8.8	2.2	0.0	3.6
Mixture of terphenyls and quarterphenyls	75	75	75	-	-	-	44.3	46.2	37.9	1	1	3	104.0	96.0	91.5	1.0	1.0	3.3	1.7
Mixture of terphenyls and quarterphenyls	100	100	100	-	-	-	25.0	16.8	29.9	0	5	4	107.7	83.8	101.5	0.0	6.0	3.9	3.3
Mixture of terphenyls and quarterphenyls	5	5	5	+10%	+10%	+10%	98.1	89.2	101.0	4	8	6	91.5	86.5	84.2	4.4	9.2	7.1	7.0
Mixture of terphenyls and quarterphenyls	25	25	25	+10%	+10%	+10%	89.7	70.8	76.6	7	7	1	86.0	103.3	93.5	8.1	6.8	1.1	5.4
Mixture of terphenyls and quarterphenyls	50	50	50	+10%	-	-	69.6	73.0	70.6	Culture contaminated
Mixture of terphenyls and quarterphenyls	75	75	75	+10%	+10%	+10%	51.8	53.7	60.2	7	6	3	94.5	97.3	79.3	7.4	6.2	3.8	5.9
Mixture of terphenyls and quarterphenyls	100	100	100	+10%	+10%	+10%	48.8	44.5	52.2	8	12	2	82.2	85.5	70.3	9.7	14.0	2.8	8.8

Conclusions:

Interpretation of results:negative
The results for the Mixture of terphenyls and quarterphenyls were negative in the CHO/HGPRT Mammalian Cell Forward Gene Mutation Assay.
The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance mixed terphenyl (containing mainly m-terphenyl, o-terphenyl and only a mino content of p-terphenyl) and a minor content of quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups.
Therefore both substances are expected to follow the same toxicokinetic pattern.

Executive summary:

The mixture of terphenyls and quarterphenyls was evaluated for cytotoxicity in Chinese Hamster Ovary Cells (CHO), clone K1 designated CHO-K1 -BH4 at dose levels of 0.33, 1.0, 3.33, 10, 3.33 100, 333 and 1000 µg/mL of treatment volume at concentrations of 0, 1, 2, 5, and 10% metabolic activations (S9) preparation. The Mixture of terphenyls and quarterphenyls precipitated out of solution at the 100, 333 and 1000 µg/mL dose levels. There was complete cytotoxicity at the 333 µg/mL dose level at the 1, 2, 5 and 10% S9 levels, however relative survivals of 69.9, 37.9, 44 and 42.4% were abserved at the 1000 µg/mL at similar S9 concentrations. Results at the 100 µg/mL dose level showed 0, 59, 61.6 and 58.7% relative cell survivals at the 1, 2, 5 and 10% S9 concentrations, respectively. Results without metabolic activation produced 67.4, 45.3 and 66.6% relative cell survival at the 100, 333 and 1000 µg/mL dose levels, respectively.

Based on these findings, the Mixture of terphenyls and quarterphenyls was evaluated in a preliminary mutagenicity screen at dose levels of 20, 50 and 100 µg/mL of treatment volume at 1, 2, 5 and 10% concentrations of metabolic activation (S9) preparation. At these dose levels and S9 concentrations, there were no statistically significant increases in the mutation frequencies observed in the treated cultures, however, a dose dependent trend was noted within the 10% S9 concentration treated cultures.

The Mixture of terphenyls and quarterphenyls was evaluated in the CHO/HGPRT Mammalian Cell Forward Gene Mutation Assay at dose levels of 5, 25, 50, 75 and 100 µg/mL of treatment volume without and with a 10% (v/v) concentration of metabolic activation (S9) preparation. There were no statistically significant increases in the mutation frequencies of Mixture of terphenyls and quarterphenyls treated cultures.

The results for the Mixture of terphenyls and quarterphenyls were negative in the CHO/HGPRT Mammalian Cell Forward Gene Mutation Assay according to the criteria of the test protocol.

The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance mixed terphenyl (containing mainly m-terphenyl, o-terphenyl and only a mino content of p-terphenyl) and a minor content of quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups.

Therefore both substances are expected to follow the same toxicokinetic pattern.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Genetic toxicity in vivo

Description of key information

Read Across from terphenyl (CAS 26140 -60 -3) more specifically a Mixture or terphenyls and quarterphenyls; Key study: Genetic toxicity in vitro, (Mammalian Bone Marrow Chromosome Aberration Test (OECD 475), negative

Link to relevant study records

Reference

Endpoint:

in vivo mammalian somatic cell study: cytogenicity / bone marrow chromosome aberration

Remarks:

Type of genotoxicity: chromosome aberration

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
In this justification, the read-across (bridging) concept is applied, based on the chemical structure of the potential analogues, their toxicokinetic behaviour and other available (eco-)toxicological data.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance terphenyl (containing mainly m-terphenyl, o-terphenyl and only little p-terphenyl as well al a low percentage of quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups. Obviously, the contained isomers are only different to a minor extent. Moreover, all isomers have common functional group(s). In addition, they were simulated to have the same breakdown products using the In vivo rat metabolism simulator and the Rat liver S9 metabolism simulator (OECD QSAR Toolbox v4.2).
Therefore, both substances are expected to follow the same toxicokinetic pattern.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)

source substance:
Mixture of terphenyls (mainly m- and o-terphenyls and only a minor content of p-terphenyl) and quarterphenyls (ca. 25 %)
structural formula: C18H14 and C24H18
The terphenyl substance consists of three constituents, each with their own Smiles notation and structural formula:
o-terphenyl: c(c(c(cccc1)c1)ccc2)(c(cccc3)c3)c2
m-terphenyl: c(c(cccc1)c1)(cccc2c(cccc3)c3)c2
p-terphenyl: c(c(cccc1)c1)(ccc(c(cccc2)c2)c3)c3
The quarterphenyls:
ortho-/ortho-:c1cccc(c1c1ccccc1)c1ccccc1c1ccccc1
ortho-/meta-: c1c(cccc1c1ccccc1c1ccccc1)c1ccccc1
ortho-/para-: c1cc(ccc1c1ccccc1)c1ccccc1c1ccccc1
meta-/meta-: c1c(cccc1c1cccc(c1)c1ccccc1)c1ccccc1
meta-/para-: c1cc(ccc1c1ccccc1)c1cccc(c1)c1ccccc1
para-/para-: c1cc(ccc1c1ccccc1)c1ccc(cc1)c1ccccc1
CAS 26140-60-3
EC No 247-477-3
purity: not specified

target substance:
Reaction mass of m-terphenyl and o-terphenyl (100 % m- and o-terphenyl)
structural formula: C18H14
The substance consists of two constituents, each with their own Smiles notation and structural formula:
o-terphenyl: c(c(c(cccc1)c1)ccc2)(c(cccc3)c3)c2
m-terphenyl: c(c(cccc1)c1)(cccc2c(cccc3)c3)c2
CAS -
EC No 904-797-4
purity: ≥ 90 - ≤ 100 % (w/w)

3. ANALOGUE APPROACH JUSTIFICATION
Reaction mass of m-terphenyl and o-terphenyl and Mixture of terphenyls and quarterphenyls (ca. 2 5 %) belong to the group of closely related aromatic hydrocarbons. Terphenyls, also known as diphenylbenzenes or triphenyls, consist of a central benzene ring substituted with two phenyl groups.

Both chemicals are expected to be metabolised similarly building similar metabolites (“common breakdown product").
The similar findings (refer to data matrix outlined below) for both substances support the conclusion that similar molecules will be formed from both substances when applied systemically. In consequence, Mixture of terphenyls and quarterphenyls may perfectly serve as read-across substance for Reaction mass of m-terphenyl and o-terphenyl and vice versa. So, the available data on Mixture of terphenyls and quarterphenyls can be used to cover all systemic endpoints currently lacking from Reaction mass of m-terphenyl and o-terphenyl, making further testing obsolete.

4. DATA MATRIX
There is mainly physico-chemical data available on the toxicological properties of Reaction mass of m-terphenyl and o-terphenyl. Data on Mixture of terphenyls and quarterphenyls covers the acute toxicity to inhalation endpoint and genetic mutation in vitro and in vivo endpoint. The identification and discussion of common properties will be based on available data including toxicological and physicochemical data.
The physical state of the two substances is solid (Reaction Mass of m-terphenyl and o-terphenyl is a cream coloured solid block at room temperature; Mixture of terphenyls and quarterphenyls is a soft solid melting to yellow liquid at room temperature). Their melting point lies at 32 °C and 40-70 °C; their boiling point at 355°C and approximately 400 °C. Furthermore, their density is quite similar (1.11 x 10E3 kg/m3 at 20.0 ± 0.5 ºC and 1.041 x 10E3 kg/m3 at 25 ºC or 1.081 kg/m³ at 60°C) and the vapour pressure is expected to be in the same range ((1.8 x 10E-2 Pa at 25 °C, corresponding to 1.7765 x 10E-7 atmosphere for Reaction mass of m-terphenyl and o-terphenyl and 11 mm Hg at 200°c for Mixture of terphenyls and quarterphenyls); the estimated vapour pressure of the o-, m- and p-terphenyls ranged from 4.3 x 10E-7 to 8.0 x 10E-10 atmosphere)).
The available data for the following physico-chemical properties, which are relevant for absorption into living organisms, are very similar. Both substances are medium sized molecules with a molecular weight of 230.31 (Reaction mass of m-terphenyl and o-terphenyl) resp. 230 and 306 (Mixture of terphenyls and quarterphenyls)), they are both either insoluble expected to be insoluble to slightly soluble in water (Less than 1.0 x 10E-4 g/L of solution at 20.0 ± 0.5 °C (Reaction mass of m-terphenyl and o-terphenyl)=. Moreover, they have a rather high logPow (3.01 to 5.94 (Reaction mass of m-terphenyl and o-terphenyl) and 5.86 at 22°C (Mixture of terphenyls and quarterphenyls)). Both chemicals are not readily biodegradable and they are not expected to be hydrolysed due to lack of functional groups. For Reaction mass of m-terphenyl and o-terphenyl a QSAR calculation has been performed for the bioconcentration factor (BCF). For both - m-terphenyl and o-terphenyl - a BCF of 2041 L/kg wet-wt (3.31 log BCF) was predicted. Mixture of terphenyls and quarterphenyls has a low potential for bioaccumulation in aquatic organisms.

There is only data available for the target substance Reaction mass of m-terphenyl and o-terphenyl for the following toxicological endpoints: Repeated dose toxicity oral and Toxicity to reproduction (fertility / developmental toxicity).
Moreover, there is data available for the Read Across substance Mixture of terphenyls and quarterphenyls for the following endpoints: Acute toxicity to inhalation, Genetic toxicity in vitro and Genetic toxicity in vivo.
The Read Across substance Mixture or terphenyls and quarterphenyls has been shown to be not mutagenic. For Reaction mass of m-terphenyl and o-terphenyl a NOAEL of 100 mg/kg bw was derived for the endpoint Repeated dose toxicity oral and for reproduction / developmental toxicity, based on effects around parturition at 300 mg/kg/day.

Reason / purpose for cross-reference:

read-across source

Sex:

male/female

Genotoxicity:

negative

Vehicle controls validity:

valid

Positive controls validity:

valid

Additional information on results:

RESULTS OF RANGE-FINDING STUDY
- Dose range: 4, 20, 100, 500, or 2500 mg/kg
- Clinical signs of toxicity in test animals: There was no significant effect of treatment with Mixture of terphenyls and quarterphenyls on body weight during the 14-day period of the study. No significant clinical signs of toxicity were noted during the study, and no animals died as a result of treatment with the Mixture of terphenyls and quarterphenyls.

PILOT STUDIES
- Dose range: 0, 500, 240, 3350, 5000 mg/kg
- Clinical signs of toxicity in test animals: In the 24-hour pilot study, there was no consistent, significant effect of treatment with the Mixture of terphenyls and quarterphenyls on animal body weights or mitotic indices. No significant clinical signs of toxicity were observed.
In the 14-day pilot study, the mean body weight gain was depressed for males treated with 3350 and 5000 mg/kg the Mixture of terphenyls and quarterphenyls. None of the animals died. The only signs of toxicity observed were rough fur for several animals and swelling at the site of injection of the Mixture of terphenyls and quarterphenyls in one male and two females treated with 5000 mg/kg. An LD50 value for the Mixture of terphenyls and quarterphenyls could not be calculated because there were no deaths.

RESULTS OF DEFINITIVE STUDY
- Clinical signs of toxicity in test animals: Moderate exudates from one eye were observed in one female (5000 mg/kg dose group) and one male (500 mg/kg dose group) on the afternoon after dosing. The eyes of these animals were clear the next day. No other signs of toxicity were observed.
- Cytological observations: At 6, 12, and 24 hour posttreatment, no significant differences in any of the three measures of cytological damage evaluated were observed between the negative control and the Mixture of terphenyls and quarterphenyls-treatment groups in male or female rats.
- Appropriateness of dose levels and route: Based on results from the pilot studies.
- Statistical evaluation: The three measures of cytological damage that were statistically evaluated were the MI, the percentage of chromosomally aberrant cells, and the frequency of chromosomal aberrations per cell.

Cytogenetic evaluation of bone marrow cells treated with the Mixture of terphenyls and quarterphenyls:

	Female rats
	6-hour sacrifice		12-hour sacrifice		24-hour sacrifice
	Negative control	5000 mg/kg test item	Negative control	5000 mg/kg test item	Negative control	5000 mg/kg test item	0.2 mg/kgTEM
Number of animals	5	5	5	5	5	5	5
Mitotic Index * (Mean % ±SEM)	2.44 ± 0.60	2.61 ± 0.60	5.14 ± 0.98	3.52 ± 1.18	2.20 ± 0.51	3.77 ± 0.61	1.49 ± 0.42
Number of cells analyzed	300	300	300	300	298	300	300
Number of aberrant cells° (Mean % ±SEM)	1 (0.33 ± 0.33)	0	0	0	1 (0.34 ± 0.34)	0	134 (44.67 ± 9.09)
Number of cells with structurally abnormal chromosomes (Mean % ±SEM)	0	0	0	0	1 (0.34 ± 0.34)	0	131 (43.67 ± 9.01)
Number of cells (%) with:
Chromosome deletions	0	0	0	0	0	0	0
Chromosome exchanges	0	0	0	0	0	0	0
Chromatid deletions	0	0	0	0	1 (0.34)	0	36 (17.48)
Chromatid exchanges	0	0	0	0	0	0	6 (2.91)
Aneuploidy	1 (0.33)	0	0	0	0	0	1 (1.46)
Plyploidy	0	0	0	0	0	0	0
Severe damage	0	0	0	0	0	0	94 (31.33)
Types of aberrations per cell:
Overall frequency of aberrations** (Mean % ±SEM)	0.003 ± 0.003	0	0	0	0.003 ± 0.003	0	1.820 ± 0.508
Chromosome deletions	0	0	0	0	0	0	0
Chromosome exchanges	0	0	0	0	0	0	0
Chromatid deletions	0	0	0	0	1 (0.003)	0	65 (0.316)
Chromatid exchanges	0	0	0	0	0	0	8 (0.039)
Number of cells (%) with:
Chromatid gaps	1 (0.33)	1 (0.33)	2 (0.67)	2 (0.67)	0	0	7 (3.40)
Chromosome gaps	0	0	0	0	0	0	0

 

	Male rats
	6-hour sacrifice		12-hour sacrifice		24-hour sacrifice
	Negative control	5000 mg/kg test item	Negative control	5000 mg/kg test item	Negative control	5000 mg/kg test item	0.2 mg/kgTEM
Number of animals	5	5	5	5	5	5	5
Mitotic Index * (Mean % ±SEM)	4.57 ± 1.15	5.38 ± 1.45	6.06 ± 2.97	7.24 ± 1.88	6.10 ± 0.68	4.75 ± 0.50	2.53 ± 0.37
Number of cells analyzed	300	290	300	300	300	300	300
Number of aberrant cells° (Mean % ±SEM)	0	0	1 (0.33 ± 0.33)	1 (0.33 ± 0.33)	1 (0.33 ± 0.33)	0	117 (39.00 ± 6.47)
Number of cells with structurally abnormal chromosomes (Mean % ±SEM)	0	0	0	0	0	0	116 (38.67 ± 6.76)
Number of cells (%) with:
Chromosome deletions	0	0	0	0	0	0	0
Chromosome exchanges	0	0	0	0	0	0	0
Chromatid deletions	0	0	0	0	0	0	30 (13.45)
Chromatid exchanges	0	0	0	0	0	0	19 (8.52)
Aneuploidy	0	0	1 (0.33)	1 (0.33)	1 (0.33)	0	1 (0.45)
Plyploidy	0	0	0	0	0	0	0 (0.00)
Severe damage	0	0	0	0	0	0	77 (25.67)
Types of aberrations per cell:
Overall frequency of aberrations** (Mean % ±SEM)	0	0	0.003 ± 0.003	0.03 ± 0.003	0.003 ± 0.003	0	1.547 ± 0.309
Chromosome deletions	0	0	0	0	0	0	0
Chromosome exchanges	0	0	0	0	0	0	0
Chromatid deletions	0	0	0	0	0	0	49 (0.220)
Chromatid exchanges	0	0	0	0	0	0	29 (0.130)
Number of cells (%) with:
Chromatid gaps	0	1 (0.34)	0	2 (0.67)	0	1 (0.33)	6 (2.69)
Chromosome gaps	0	0	0	0	0	0	1 (10.45)

Conclusions:

Interpretation of results: negative
The Mixture of terphenyls and quarterphenyls does not induced chromosomal damage in the in vivo micronucleus test.
The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance Mixture of terphenyls (containing mainly m-terphenyl, o-terphenyl and only a mino content of p-terphenyl and a minor content of quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups.
Therefore, both substances are expected to follow the same toxicokinetic pattern. For the detailed procedure of the read-across principle and justifications, please refer to the analogue approach justification depicted above.

Executive summary:

This study assessed the ability of the Mixture of terphenyls and quarterphenyls administered by intra-peritoneal injection to induce chromosomal damage in bone marrow cells for Fischer 344 rats. In the definitive study, rats were given the Mixture of terphenyls and quarterphenyls at doses of 0, 500, 2500 and 5000 mg/kg body weight. Groups of animals were sacrificed 6, 12 and 24 hrs after treatment. Cells from animals exposed to 0 and 5000 mg/kg and those from animals in the positive control groups were evaluated microscopically for mitotic index and chromosomal abnormalities. On the basis of those results, it could be concluded that the Mixture of terphenyls and quarterphenyls dose not induce chromosomal damage in male and female Fischer 344 rats under the conditions used in this study.

The target substance Reaction mass of m-terphenyl and o-terphenyl and the source substance Mixture of terphenyls (containing mainly m-terphenyl, o-terphenyl and only a mino content of p-terphenyl and a minor content of quarterphenyls) used in this study belong to the group of closely related aromatic hydrocarbons. Also known as diphenylbenzenes or triphenyls, they consist of a central benzene ring substituted with two phenyl groups.

Therefore, both substances are expected to follow the same toxicokinetic pattern. For the detailed procedure of the read-across principle and justifications, please refer to the analogue approach justification depicted above.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (negative)

Additional information

There are no data available for the target substance. However, several reliable test results are available for structurally related read across substances. The results of these will be described in the following.

In vitro:

In vitro bacterial cells - Gene mutations

The key study for the read across substance Mixture of toluene soluble terphenyls and quarterphenyls for gene mutations in bacterial cells is an Ames reverse mutation test (K1, equivalent of similar to OECD 471, GLP). The test substance Mixture of toluene soluble terphenyls and quarterphenyls was subjected to the Ames test according to the procedure described in the original paper by Ames et al. (1975). Test concentrations were 0.1, 1.0, 10.0, and 500.0 µg/plate. S. typhimurium strains TA 1535, TA 1537, TA 98 and TA 100 were used. The positive controls confirmed that the bacterial strains were active. Increased numbers of revertants were seen in TA100 strains in replicate assays. This activity was observed only in the presence of S9 activating enzymes. All other strains were negative, both with and without metabolic activation (TA98, TA1535 and TA1537). As such, the results are overall interpreted as equivocal.

Two supporting (K2) Ames studies (one performed with Mixture of terphenyls and quarterphenyls and one with a Mixture of quarterphenyls and higher polyphenyls) - in which the same strains and concentrations as in the key study were used - showed no mutagenic activity in any of the strains, both with and without metabolic activation. Additionally, in these tests a Saccharomyces cerevisiae D4 strain and a S. typhimurium TA 1538 strain were subjected to the same test conditions, and showed no gene mutation effect both with and without metabolic activation.

Based on the overall results from these three tests the test substances were not shown to be genotoxic in the majority of the tests. Without metabolic activation, no genotoxicity was observed in any of the tests, with metabolic activation genotoxicity was observed in one strain (TA100) in one of the tests (this increase can not be judged to be biologically relevant, due to only a small increase of the number of reverants by the factor of 1.5). Therefore, no definitive conclusion on genotoxicity can be drawn based on the results of these Ames tests alone.

In vitro mammalian cells – Gene mutations

The key study for the structurally related read across substance (Mixture of terphenyls (mainly m- and o-terphenyls and only a minor content of p-terphenyl)) and quarterphenyls for gene mutations in mammalian cells is a GLP (OECD guideline 476) , K1 study addressing forward gene mutation effects on Chinese Hamster Ovary (CHO) cell lines targeting the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus. Tested concentrations were 5, 25, 50, 75 and 100 µg/mL, both with and without metabolic activation. The cytotoxicity of the test substance Mixture of terphenyls and quarterphenyls was tested at 8 doses ranging from 0.3 to 1000 µg/mL of media, which was well above the solubility limit of the test substance. Cell lines treated with test substance did not show increased mean mutation frequencies both with and without metabolic activation. The test substance Mixture of terphenyls and quarterphenyls as a consequence is not considered to introduce gene mutations in mammalian cells according to the described study protocol.

The supporting study (K2) evaluated the same endpoints as the key study, but used a substance with a slightly different composition (Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls). This supporting study completely supported the findings of the key study, no gene mutations in mammalian cells were observed.

In vitro mammalian cells – Chromosome aberration

A GLP in vitro chromosome aberrations test with the structurally related read across substance (Mixture of terphenyls (mainly m- and p-terphenyls and only a minor content of o-terphenyl) and quarterphenyls was performed according to the OECD 473 guideline. Chinese hamster ovary cells were exposed to 37.5, 75.0 or 150.0 µg/mL of the Mixture of terphenyls and quarterphenyls for 24 hours in the absence of metabolic activation or 2 hours with metabolic activation. Cytotoxicity was evaluated by exposing cells in culture in a range-finder test with concentrations ranging from 9.4 to 150.0 µg/mL. The doses chosen for the cytogenetic assay were based upon the findings from this cytotoxicity test. The cells were microscopically evaluated for mitotic indices and for chromosomal aberrations. The chromosome aberrations test showed no significant differences between the solvent control and the cells treated with test substance. As a consequence, the outcome of the test is negative and the test substance can be considered to have no clastogenic effects in Chinese hamster ovary cells.

Conclusion in vitro results:

Based on all available in vitro tests, the substance does not appear to be genotoxic.

 

In vivo:

One K1 in vivo micronucleus test is available for the structurally related read across substance (Mixture of terphenyls (mainly m- and o-terphenyls and only a minor content of p-terphenyl) and quarterphenyls). The test is conducted according to GLP and equivalent to OECD Guideline 475. Groups of 6 animals per sex per dose per time of sacrifice received a single intraperitoneal dose of test substance Mixture of terphenyls and quarterphenyls at 500, 2500 and 5000 mg/kg bw. Groups of rats were sacrificed 6, 12 and 24 hours after treatment. At 6, 12 and 24 hour post-treatment, no significant differences in mitotic index, % of chromosomally aberrant cells and frequency of chromosomal aberrations per cell were observed between the group treated with the test substance and the negative control group. It can thus be concluded that the test substance Mixture of terphenyls and quarterphenyls does not induce chromosomal damage in this in vivo micronucleus test.

 

Overall conclusion in vitro and in vivo:

Based on all tests results from in vitro and in vivo studies it can be concluded that the substance is not genotoxic by any of the mechanisms described.

Endpoint Conclusion: No adverse effect observed (negative)

Justification for classification or non-classification

Based in the available data, the classification is not warranted according to the criteria of EU Classification, Labelling and Packaging of Substances and Mixtures (CLP) Regulation No 1272/2008.