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Diss Factsheets

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

In response to the Final Decision Letter (dated 03 July 2020) CCH- D-2114515259 -48 -01/F three new in vitro genetic toxicity studies (Ames test (OECD 471), mouse micronucleus assay (OECD 487) and mouse lymphoma assay (OECD 490)) were conducted on the target substance. Results from all three in vitro studies were negative, fulfilling all information requirements.

Link to relevant study records

Referenceopen allclose all

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
09-Nov-2020 to 20-Nov-2020
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Qualifier:
according to guideline
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Qualifier:
according to guideline
Guideline:
EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)
GLP compliance:
yes (incl. QA statement)
Type of assay:
bacterial reverse mutation assay
Target gene:
S. typhimurium strains: his-operon
E. coli strains: tryptophan-operon
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Species / strain / cell type:
E. coli WP2 uvr A pKM 101
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced S9
Vehicle / solvent:
Dimethyl sulfoxide (DMSO)
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
9-aminoacridine
2-nitrofluorene
sodium azide
other: 2-aminoanthracene, Potassium dichromate
Details on test system and experimental conditions:
Preliminary assessment of solubility
A preliminary solubility assessment was conducted for the test item, Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9), at 100 mg per mL in dimethyl sulphoxide (DMSO). As the test item dissolved in DMSO at 100 mg per mL, solubility was not assessed with any other solvents and DMSO was used as the solvent for the test item throughout this study.

Mutagenicity tests
Test 1
A plate incorporation mutagenicity test was performed using Salmonella typhimurium LT2 strains TA1535, TA1537, TA98 and TA100, and Escherichia coli WP2 strain uvrA/pKM101, in both the presence and absence of S9 mix. In all cases there were three plates in the solvent control, test item and positive control groups.

Test 2
For Test 2, a liquid pre-incubation test was performed using Salmonella typhimurium LT2 strains TA1535, TA1537, TA98 and TA100, and Escherichia coli WP2 strain uvrA/pKM101 in the presence and absence of S9 mix. In all cases there were three plates in the solvent control, test item and positive control groups.

Test item administration
The test item was administered in solvent (DMSO) at a volume of 100 μL per plate for the plate incorporation method and a volume of 50 μL per plate when the liquid pre-incubation method was employed, within a maximum of three hours of formulation.
Evaluation criteria:
Test acceptance criteria
A minimum of five analysable (scoreable) concentrations was required, with at least four showing no signs of cytotoxicity.

Evaluation
Cytotoxicity
A dose of the test item was judged to be toxic to a bacterial strain if the formation of microcolonies (background lawn) was reduced, or a relevant decrease in the number of revertant colonies was seen.

Mutagenicity
A test item was considered to be mutagenic if the following criteria were satisfied:
- For all five strains, the mean number of revertant colonies is equal to or greater than 2 times the concurrent solvent control mean value at one or more doses of the test item, with or without. In addition, for TA1535 and TA1537, the mean number of revertant colonies of one or more doses of the test item, with or without metabolic activation must be equal to or greater than 2 times the relevant historical mean value.
- There was a dose-related increase in the number of revertant colonies.
- A reproducible (at one or more doses) increase in numbers of revertant colonies per plate in at least one strain with or without metabolic activation.
Statistics:
The mean number of revertant colonies and standard deviations were calculated for all groups.
All valid data were plotted and analysed using a linear regression analysis programme.
Key result
Species / strain:
S. typhimurium TA 1535
Remarks:
Plate incorporation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: above 5000 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Remarks:
Plate incorporation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: above 5000 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Remarks:
Plate incorporation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: above 5000 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Remarks:
Plate incorporation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: above 5000 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A pKM 101
Remarks:
Plate incorporation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1535
Remarks:
Liquid pre-incubation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
above 500 μg/plate without metabolic activation; 1600 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 1537
Remarks:
Liquid pre-incubation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
above 500 μg/plate without metabolic activation; 1600 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 98
Remarks:
Liquid pre-incubation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
above 500 μg/plate without metabolic activation; 1600 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
S. typhimurium TA 100
Remarks:
Liquid pre-incubation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
above 500 μg/plate without metabolic activation; 1600 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Key result
Species / strain:
E. coli WP2 uvr A pKM 101
Remarks:
Liquid pre-incubation test
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
5000 μg/plate with metabolic activation
Vehicle controls validity:
valid
Positive controls validity:
valid
Additional information on results:
Plate incorporation test
On the day of dosing, precipitate was seen at and above 500 μg per plate for all five strains in both the presence and absence of S9 mix. On the day of scoring, precipitate was seen at and above 1600 μg per plate for all five strains in both the presence and absence of S9 mix.
Evidence of cytotoxicity as indicated by reductions in the growth of the background lawns or in the incidence of spontaneous revertant colonies was seen at a dose of 5000 μg per plate for the four S. typhimurium strains in the absence of S9 mix.
No significant increase in numbers of revertant (histidine or tryptophan-independent) colonies was seen with any of the five indicator strains either in the presence or absence of S9 mix.

Liquid pre-incubation test
On the day of dosing precipitate was seen at and above 500 μg per plate for all five strains in both the presence and absence of S9 mix. On the day of scoring, precipitate was seen at and above 1600 μg per plate for all five strains in both the presence and absence of S9 mix.
Evidence of cytotoxicity as indicated by reductions in the growth of the background lawns or in the incidence of spontaneous revertant colonies was seen at and above a dose of 500 μg per plate for the four S. typhimurium strains in the absence of S9 mix, at and above 1600 μg per plate for four S. typhimurium strains in the presence of S9 mix, and at 5000 μg per plate for the E. coli strain in the absence of S9 mix.
No significant increase in numbers of revertant (histidine or tryptophan-independent) colonies was seen with any of the five indicator strains either in the presence or absence of S9 mix.
Remarks on result:
other: all strains/cell types tested
Remarks:
no mutagenic potential

Table 1 – Test 1: Petroleum Gas Oil Fraction, Co-pressed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): plate incorporation method – with metabolic activation

Dose per plate

Number of revertant colonies per plate

S. typhimuriumLT2

E. coliWP2

 

TA1535

TA1537

TA98

TA100

uvrA/pKM101

μg

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Solvent control

12

2.1

11

1.5

37

2.5

138

10.0

201

7.8

1.6

14

2.1

13

1.2

34

4.5

154

5.0

202

14.6

5

12

2.0

12

0.6

33

3.2

142

11.4

201

12.4

16

10

1.0

13

1.5

36

2.1

131

7.8

214

1.5

50

13

2.1

11

1.5

31

6.1

120

11.2

187

9.5

160

12

2.0

12

2.1

34

7.6

147

6.2

191

17.9

500

11

3.1

9

1.2

38

3.1

142

18.5

192

14.7

1600

11

4.7

10

3.2

39

2.6

150

11.4

194

14.0

5000

11

4.9

15

1.5

40

11.4

152

3.8

178

17.6

Positive control

176

7.5

152

4.5

1586

180.4

2455

20.9

1945

21.4

Positive controls

TA1535: 2-aminoanthracene 2 μg/plate
TA1537: 2-aminoanthracene 2 μg/plate
TA98: 2-aminoanthracene 2 μg/plate
TA100: 2-aminoanthracene 2 μg/plate
uvrA/pKM101: 2-aminoanthracene 20 μg/plate

 

Table 2 – Test 1: Petroleum Gas Oil Fraction, Co-pressed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): plate incorporation method – without metabolic activation

Dose per plate

Number of revertant colonies per plate

S. typhimuriumLT2

E. coliWP2

 

TA1535

TA1537

TA98

TA100

uvrA/pKM101

μg

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Solvent control

15

1.5

11

0.6

27

0.6

128

2.0

170

4.2

1.6

14

2.1

11

2.0

28

2.0

122

2.6

156

10.0

5

13

2.0

9

3.2

25

5.6

113

10.6

165

2.0

16

14

1.5

10

0.6

24

7.1

104

2.5

173

3.0

50

11

1.7

9

3.8

23

6.1

110

3.2

155

4.2

160

12

1.2

11

1.5

23

7.0

110

9.7

150

13.9

500

14

2.6

12

1.7

26

4.5

113

12.8

141

8.3

1600

11

0.6

10

2.5

25

5.5

101

10.8

141

10.0

5000

10

2.0

9

1.5

24

2.1

100

8.2

145

5.7

Positive control

432

7.6

195

8.3

360

13.1

558

28.3

1000

57.3

Positive controls

TA1535: sodium azide 0.5 μg/plate
TA1537: 2-aminocridine.HCl 50 μg/plate
TA98: 2-nitrofluorene 1 μg/plate
TA100: sodium azide 0.5 μg/plate
uvrA/pKM101: potassium dichromate 25 μg/plate

 

Table 3 – Test 2: Petroleum Gas Oil Fraction, Co-pressed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): liquid pre-incubation method – with metabolic activation

Dose per plate

Number of revertant colonies per plate

S. typhimuriumLT2

E. coliWP2

 

TA1535

TA1537

TA98

TA100

uvrA/pKM101

μg

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Solvent control

10

0.6

9

1.0

32

3.1

142

6.7

209

6.7

1.6

11

1.0

10

2.1

31

2.6

148

5.0

193

7.6

5

12

1.0

8

2.6

18

8.1

140

16.6

197

23.5

16

10

0.6

8

2.0

29

6.6

115

19.3

197

8.6

50

10

3.1

8

2.0

30

6.0

120

9.2

208

1.5

160

9

3.1

9

3.5

24

2.1

113

28.7

192

7.0

500

10

2.1

9

3.2

25

5.5

125

2.1

204

13.2

1600

7

2.0

6

2.1

25

5.6

116

11.8

195

12.7

5000

8

1.5

8

1.5

25

1.0

111

11.0

175

8.5

Positive control

126

1.5

102

6.1

1327

105.1

1769

35.4

1844

56.7

Positive controls

TA1535: 2-aminoanthracene 2 μg/plate
TA1537: 2-aminoanthracene 2 μg/plate
TA98: 2-aminoanthracene 2 μg/plate
TA100: 2-aminoanthracene 2 μg/plate
uvrA/pKM101: 2-aminoanthracene 20 μg/plate

 

Table 4 – Test 2: Petroleum Gas Oil Fraction, Co-pressed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): liquid pre-incorporation method – without metabolic activation

Dose per plate

Number of revertant colonies per plate

S. typhimuriumLT2

E. coliWP2

 

TA1535

TA1537

TA98

TA100

uvrA/pKM101

μg

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Mean

SD

Solvent control

13

1.2

9

0.6

28

1.2

118

2.5

146

7.2

1.6

12

1.0

9

0.6

27

5.7

120

4.2

148

7.1

5

12

2.0

8

1.0

26

1.7

113

3.5

135

2.0

16

11

2.6

9

2.1

28

2.1

116

6.8

143

5.0

50

10

1.5

11

1.2

27

4.5

110

3.6

132

6.8

160

11

2.1

8

1.2

23

6.0

101

3.0

128

6.0

500

10

2.6

5

3.1

16

1.5

98

8.9

121

7.8

1600

5

1.2

4

0.6

17

3.1

76

14.5

122

17.4

5000

7

1.0

3

1.5

15

3.0

100

7.8

100

4.0

Positive control

435

22.0

175

15.0

343

27.4

444

28.0

939

29.7

Positive controls

TA1535: sodium azide 0.5 μg/plate
TA1537: 2-aminocridine.HCl 50 μg/plate
TA98: 2-nitrofluorene 1 μg/plate
TA100: sodium azide 0.5 μg/plate
uvrA/pKM101: potassium dichromate 25 μg/plate

Conclusions:
It was concluded that Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) was not mutagenic for Salmonella typhimurium LT2 strains TA1535, TA1537, TA98 and TA100, and Escherichia coli WP2 strain uvrA/pKM101, either in the presence or absence of S9 mix, when tested under the conditions used in this assay.
Executive summary:

Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) was tested for mutagenic activity using genetically modified Salmonella typhimurium LT2 bacteria of strains TA1535, TA1537, TA98 and TA100, and Escherichia coli WP2 strain uvrA/pKM101 as indicator organisms, according to the methods of Maron and Ames, 1983, Venitt et al, 1984, Mortelmans and Zeiger, 2000 and Mortelmans and Riccio, 2000.

A preliminary solubility test was conducted. Dimethyl sulphoxide was found to be suitable and was therefore used throughout this study as the solvent for the test item.

A mutagenicity test was conducted for Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) using the plate incorporation method (Test 1) for all five indicator strains in both the presence and absence of an in vitro activation system based on S9 fraction obtained from Aroclor 1254-induced rat liver (S9 mix). The dose range used was 1.6 to 5000 μg per plate. As the result of Test 1 was clearly negative, a confirmatory test was carried out using the liquid pre-incubation method, Test 2, using a dose range of 1.6 to 5000 μg per plate in the presence and absence of S9 mix.

The test item showed evidence of cytotoxicity. The minimum dose level at which cytotoxicity was seen was 500 μg per plate. The maximum dose level scored for revertant colonies was 5000 μg per plate. The minimum dose level at which precipitate was seen on the test plates was 1600 μg per plate.

No significant increase in numbers of revertant (histidine or tryptophan-independent) colonies was seen with any of the five indicator strains either in the presence or absence of S9 mix.

It was concluded that Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) was not mutagenic for Salmonella typhimurium LT2 strains TA1535, TA1537, TA98 and TA100, and Escherichia coli WP2 strain uvrA/pKM101, either in the presence or absence of S9 mix, when tested under the conditions used in this assay.

Endpoint:
in vitro cytogenicity / micronucleus study
Type of information:
experimental study
Adequacy of study:
key study
Study period:
18-Jan-2021 to 25-Mar-2021
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 487 (In vitro Mammalian Cell Micronucleus Test)
GLP compliance:
yes (incl. QA statement)
Type of assay:
in vitro mammalian cell micronucleus test
Species / strain / cell type:
human lymphoblastoid cells (TK6)
Metabolic activation:
with and without
Metabolic activation system:
Aroclor 1254 induced S9
Test concentrations with justification for top dose:
The final concentration ranges tested from which micronuclei were analysed for were:
3h +S9 treatment schedule: 296.3 to 1500 µg/mL
3h -S9 treatment schedule : 666.7 to 1500 µg/mL
continuous treatment schedule (24h -S9): 131.7 to 666.7 µg/mL

The following levels of cytotoxicity were observed, recommended maximum level of cytotoxicity (55 ± 5%) was observed in the continuous and 3h -S9 treatment schedules:
3h +S9 treatment schedule: 42.67% at 1500 µg/mL
3h -S9 treatment schedule: 52.84% at 1500 µg/mL
continuous treatment schedule (24h -S9): 55.22% at 666.7 µg/mL

For a test item exhibiting apparent cytotoxicity, the aim was that the highest concentration selected was that which yielded cytotoxicity of ~55 ± 5%. Further doses were selected from those yielding decreasing levels of cytotoxicity, as far as a no-effect dose (little or no cytotoxicity by CBPI).

For test items that did not yield apparent cytotoxicity, the three highest test concentrations were selected for further microscopic analysis.
Vehicle / solvent:
Dimethyl sulfoxide (DMSO)
Negative solvent / vehicle controls:
yes
Positive controls:
yes
Positive control substance:
colchicine
cyclophosphamide
mitomycin C
Details on test system and experimental conditions:
Test system
The study was designed to meet the requirements of OECD Guideline 487 (2016) and was agreed with the sponsor prior to commencement of the study. Since this study utilised isolated human lymphocytes and hence used cytokinesis block protocols, the specific guidance (in OECD 487) relating to lymphocytes and studies performed in the presence of cytoB, was followed.

Experimental conditions
Human lymphocytes were isolated from pooled anti-coagulated fresh blood obtained from two healthy non-smoking males and allowed to proliferate for approximately 44 to 48 hours in the presence of the mitogen, phytohaemagglutinin (PHA). Cultures of proliferating lymphocytes were exposed to the test item in the presence of S9 mix for 3 hours before cells were washed and then further incubated (humidified atmosphere of 5% CO2 at a temperature of 37oC) in fresh medium containing cytoB for approximately 21 hours. Treatments in the absence of S9 mix were performed for a 3-hour period (followed by cell washing and incubation in fresh medium containing cytoB for approximately 21 hours) and for a continuous exposure period for 24 hours. In the continuous treatment condition, cytoB was added concurrently with the test item. Duplicate cultures were treated for each test item concentration and positive control. For the solvent-treated controls, four cultures were dosed with DMSO.
Evaluation criteria:
Criteria for a clearly positive response:
- at least one of the test concentrations exhibited a statistically significant increase compared with the concurrent negative control
- the increase was dose-related in at least one experimental condition when evaluated with an appropriate trend test
- any of the results were outside the distribution of the historical solvent control range (Poisson-based 95% control limits)

Criteria for a clearly negative response
- none of the test concentrations exhibited a statistically significant increase compared with the concurrent negative control
- there was no concentration-related increase when evaluated using an appropriate trend test
- all results were inside the distribution of the historical negative control data (Poisson-based 95% control limits)

Criteria for an equivocal response
Although most experiments are expected to yield clearly positive or negative results, in some cases the data preclude making a definitive judgement about the activity of the test item. Such equivocal responses may occur regardless of the number of times the experiment was repeated.
Statistics:
The number of micronuclei analysed from 2000 binucleated cells for each selected test item dose was compared with that from the concurrent solvent control. Pair-wise statistical analysis employing a one-sided Fisher’s Exact test were used to evaluate statistical significance (p < 0.05). A linear trend test was employed (Cochran-Armitage) in order to confirm there was no dose related increase (p < 0.05).
Key result
Species / strain:
lymphocytes: micronuclei
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity, but tested up to precipitating concentrations
Vehicle controls validity:
valid
Positive controls validity:
valid
Remarks on result:
other: all strains/cell types tested
Remarks:
no mutagenic potential

Micronucleus data

Table 1 – Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): 3 hour exposure testing in the presence of S9 mix

Dose (μg/mL)

3h +S9 treatment

CBPI

% Cytostasis

% MN per dose

p-value

Solvent (DMSO)

1.599

N/A

1.0

N/A

296.3

1.550

8.15

1.2

ns

1000

1.481

19.67

1.1

ns

1500P

1.343

42.67

1.0

ns

CPA 4

1.418

30.15

4.3

2.942×10-11

CBPI = cytokinesis block proliferation index
MN per dose = micronucleated binucleates/2000 binucleates
CPA = cyclophosphamide
P = precipitate observed at the end of the treatment period
ns = not statistically significant (by Fisher’s exact test), % - individual percentages of micronucleated binucleated cells,Cochran-Armitage treated test p-value = 8.445
×10-1, therefore not statistically significant

Table 2 – Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): 3 hour exposure testing in the absence of S9 mix

Dose (μg/mL)

3h +S9 treatment

CBPI

% Cytostasis

% MN per dose

p-value

Solvent (DMSO)

1.490

N/A

1.1

N/A

666.7

1.426

13.05

1.3

ns

1000

1.315

35.63

1.1

ns

1500P

1.231

52.84

1.0

ns

MMC 50 ng/mL

1.443

9.56

4.6

1.006×10-11

CBPI = cytokinesis block proliferation index
MN per dose = micronucleated binucleates/2000 binucleates
MMC = mitomycin
P = precipitate observed at the end of the treatment period
ns = not statistically significant (by Fisher’s exact test), % - individual percentages of micronucleated binucleated cells,Cochran-Armitage treated test p-value = 5.309
×10-1, therefore not statistically significant

Table 3 – Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): continuous (24 hour) exposure testing in the absence of S9 mix

Dose (μg/mL)

3h +S9 treatment

CBPI

% Cytostasis

% MN per dose

p-value

Solvent (DMSO)

1.460

N/A

1.1

N/A

131.7

1.501

-8.91

1.1

ns

296.3

1.335

27.10

1.0

ns

444.4

1.298

35.22

1.2

ns

666.7

1.206

55.22

1.2

ns

MMC 30 ng/mL

1.376

18.26

4.5

1.043×10-11

COL 7.5 ng/mL

1.458

0.43

3.9

2.275×10-11

CBPI = cytokinesis block proliferation index
MN per dose = micronucleated binucleates/2000 binucleates
MMC = mitomycin
COL = colchicine
P = precipitate observed at the end of the treatment period
ns = not statistically significant (by Fisher’s exact test), % - individual percentages of micronucleated binucleated cells,Cochran-Armitage treated test p-value = 6.801
×10-1, therefore not statistically significant

Cytotoxicity assessment

Table 4 – Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): cytotoxicity assessment in cytokinesis blocked lymphocytes from 3 hour exposure testing in the presence of S9 mix

Concentration
µg/mL

Number of nucleated cells

CBPI

% Cytostasis

Mono-

Bi-

Multi-

Total scored

Solvent (DMSO)

208

286

7

501

1.599

0.00

5.138

sns

sns

sns

sns

ND

ND

7.707

sns

sns

sns

sns

ND

ND

11.56

sns

sns

sns

sns

ND

ND

17.34

sns

sns

sns

sns

ND

ND

26.01

sns

sns

sns

sns

ND

ND

39.02

sns

sns

sns

sns

ND

ND

58.53

sns

sns

sns

sns

ND

ND

87.79

sns

sns

sns

sns

ND

ND

131.7

sns

sns

sns

sns

ND

ND

197.5

sns

sns

sns

sns

ND

ND

296.3

231

263

6

500

1.550

8.15

444.4

250

250

1

501

1.503

16.00

666.7

251

244

5

500

1.508

15.16

1000

265

231

5

501

1.481

19.67

1500P

334

162

5

501

1.343

42.67

CPA 4 µg/mL

316

200

10

526

1.418

30.15

Mono = mononucleated cells
Bi = binucleated cells
Multi = multinucleated cells
total scored = sum of mono-, bi- and multi-
CBPI = cytokinesis block proliferation index
CPA = cyclophosphamide
sns = slide not scored/analysed
ND = not determined
P = precipitate observed at the end of the treatment period

Table 5 – Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): cytotoxicity assessment in cytokinesis blocked lymphocytes from 3 hour exposure testing in the absence of S9 mix

Concentration

µg/mL

Number of nucleated cells

CBPI

% Cytostasis

Mono-

Bi-

Multi-

Total scored

Solvent (DMSO)

283

260

4

547

1.490

0.00

5.138

sns

sns

sns

sns

ND

ND

7.707

sns

sns

sns

sns

ND

ND

11.56

sns

sns

sns

sns

ND

ND

17.34

sns

sns

sns

sns

ND

ND

26.01

sns

sns

sns

sns

ND

ND

39.02

sns

sns

sns

sns

ND

ND

58.53

sns

sns

sns

sns

ND

ND

87.79

sns

sns

sns

sns

ND

ND

131.7

sns

sns

sns

sns

ND

ND

197.5

257

241

3

501

1.493

-0.63

296.3

274

226

0

500

1.452

7.74

444.4

301

205

0

506

1.405

17.31

666.7

288

211

1

500

1.426

13.05

1000

344

156

1

501

1.315

35.63

1500P

386

116

0

502

1.231

52.84

MMC 50 ng/mL

281

218

2

501

1.443

9.56

Mono = mononucleated cells
Bi = binucleated cells
Multi = multinucleated cells
total scored = sum of mono-, bi- and multi-
CBPI = cytokinesis block proliferation index
MMC = mitomycin C
sns = slide not scored/analysed
ND = not determined
P = precipitate observed at the end of the treatment period


Table 6 – Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9): cytotoxicity assessment in cytokinesis blocked lymphocytes from continuous (24 hour) exposure testing in the absence of S9 mix

Concentration
µg/mL

Number of nucleated cells

CBPI

% Cytostasis

Mono-

Bi-

Multi-

Total scored

Solvent (DMSO)

270

230

0

500

1.460

0.00

5.138

sns

sns

sns

sns

ND

ND

7.707

sns

sns

sns

sns

ND

ND

11.56

sns

sns

sns

sns

ND

ND

17.34

sns

sns

sns

sns

ND

ND

26.01

sns

sns

sns

sns

ND

ND

39.02

sns

sns

sns

sns

ND

ND

58.53

sns

sns

sns

sns

ND

ND

87.79

240

259

2

501

1.525

-14.12

131.7

253

245

3

501

1.501

-8.91

197.5

325

174

2

501

1.355

22.76

296.3

335

164

2

501

1.335

27.10

444.4

355

141

4

500

1.298

35.22

666.7

397

103

0

500

1.206

55.22

1000

399

101

0

500

1.202

56.09

1500P

450

50

1

501

1.104

77.44

MMC 30 ng/mL

314

184

2

500

1.376

18.26

Col 7.5 ng/mL

286

199

15

500

1.458

0.43

Mono = mononucleated cells
Bi = binucleated cells
Multi = multinucleated cells
total scored = sum of mono-, bi- and multi-
CBPI = cytokinesis block proliferation index
MMC = mitocyin C
sns = slide not scored/analysed
ND = not determined
P = precipitate observed at the end of the treatment period


Conclusions:
It was concluded that Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) did not induce the formation of micronuclei (MN) in human lymphocytes in the absence and presence of S9, under the test conditions used. The criteria for a negative response were met.
Executive summary:

Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) was tested for its potential to induce micronucleus formation in thein vitro micronucleus test with manual scoring on microscope slides. In all tests none of the treatment schedules resulted in significant increases in micronucleus formation in test item treated cultures. It was concluded that Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) did not induce the formation of micronuclei (MN) in human lymphocytes in the absence and presence of S9, under the test conditions used. The criteria for a negative response were met.

Endpoint:
in vitro gene mutation study in mammalian cells
Type of information:
experimental study
Adequacy of study:
key study
Study period:
2021-AUG-19 to 2021-NOV-24
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Qualifier:
according to guideline
Guideline:
OECD Guideline 490 (In Vitro Mammalian Cell Gene Mutation Tests Using the Thymidine Kinase Gene)
Version / remarks:
2016
Deviations:
not specified
GLP compliance:
yes (incl. QA statement)
Type of assay:
in vitro mammalian cell gene mutation tests using the thymidine kinase gene
Target gene:
Thymidine kinase gene
Species / strain / cell type:
mouse lymphoma L5178Y cells
Remarks:
cells sub-line Tk+/- 3.7.2C
Details on mammalian cell type (if applicable):
CELLS USED

- Type and source of cells: Mouse lymphoma L5178Y cells of the sub-line Tk+/- 3.7.2C (AstraZeneca Genetic Toxicology, Alderley Park (Master stock Batch: 09 September 2004))

- Suitability of cells: Thymidine kinase (TK) allows cells to salvage thymidine for use in DNA synthesis; deficiency in this enzyme is not lethal because cells are able to survive using the de novo DNA synthetic pathway. Mouse lymphoma L5178Y 3.7.2C cells are heterozygous at the Tk locus (Tk+/-) and may undergo forward mutation to the Tk-/- genotype with little or no TK activity. Both Tk+/- and Tk-/- cells are viable in non-selective medium but addition of a thymidine analogue that can be phosphorylated, e.g., trifluorothymidine (TFT) to the culture results in killing of the Tk+/- heterozygotes with preferential survival of the Tk-/- mutants. The mutant frequency can thus be estimated by comparing the cloning efficiency of cells in medium with and without the selective agent, TFT, and mutagenic activity is determined by treating cultures with different concentrations of the test substance and examining the effect on mutant frequency.

For cell lines:

- Absence of Mycoplasma contamination: Gentronix L5178Y cell stocks were checked for mycoplasma and confirmed to be mycoplasma free

- Number of passages if applicable: Cells were passaged into fresh medium every 1 to 4 days for a minimum of 4 days prior to use, following this time, cells were routinely passaged every 1 to 4 days.

- Methods for maintenance in cell culture: A vial of frozen stock L5178Y cells was removed from ultra-cold storage, thawed and initiated in culture using RPMI 1640 medium containing 10% heat-inactivated horse serum (Gibco Life Technologies, UK), antibiotics and Pluronic F68. Cells were passaged into fresh medium every 1 to 4 days for a minimum of 4 days prior to use, following this time, cells were routinely passaged every 1 to 4 days. Incubation was at 37°C in a humidified atmosphere of 5% CO2 in air. On the day of the test, cells were counted, and the cell density adjusted to 1 x 10˄7 in 20 mL (3 hour experiments). Cells were resuspended in the appropriate media.

- Cell cycle length, doubling time or proliferation index: The doubling time for L5178Y cells is between approximately 8 and 11 hours (Lorge et al, 2016).

- Modal number of chromosomes: 40

- Periodically checked for karyotype stability: not specified

- Periodically ‘cleansed’ of spontaneous mutants: Frozen batches of cells were prepared from the master stock after purging of Tk-/- mutants by culturing for approximately 24 hours in medium containing methotrexate.

MEDIA USED

- Type and composition of media, CO2 concentration, humidity level, temperature, if applicable: For all applications, the medium was RPMI 1640 supplemented with, 2 mmol/L sodium pyruvate, 200 IU/mL penicillin and 200 μg/mL streptomycin. Pluronic F68 solution and heat-inactivated donor horse serum (HIDHS) were added to RPMI to give the different media used for various stages of the test, as follows:

Supplements Abbreviation Use
10% HIDHS R10 Stock cell maintenance
0.1% Pluronic F68 R0P Exposure to test substance (media replacement / dilution)
10% HIDHS + 0.1% Pluronic F68 R10P Exposure to test substance, maintenance during expression periods and general cell culture
20% HIDHS + 0.1% Pluronic F68 R20P Cloning cells for viability and TFT resistance
Additional strain / cell type characteristics:
not specified
Metabolic activation:
with and without
Metabolic activation system:
Type and composition of metabolic activation system:
- source of S9: Purchased from Molecular Toxicology Inc. (Boone, North Carolina, USA) via TRiNOVA Biochem GmbH (Germany)
- method of preparation of S9 mix: Prepared from the livers of male Sprague-Dawley rats treated with Aroclor 1254. Its metabolic capacity was demonstrated by key enzyme assays and the ability to activate reference agents to bacterial mutagens. Protein content was adjusted to 30 mg/mL by dilution with RPMI 1640 before incorporation into the S9 mix used in the study. The S9 fraction was stored deep-frozen in a -80°C freezer. Sufficient vials were removed from the -80°C freezer, thawed and used; any excess S9 fraction was discarded. The complete activation system (S9 mix) was prepared immediately before use; final concentrations in the 3 hour treatment in the presence of S9 mix were as follows:

Nicotinamide adenine dinucleotide phosphate : 0.5 mM
Glucose-6-phosphate : 2.5 mM
Rat liver homogenate (S9 fraction): 2% v/v

- concentration or volume of S9 mix and S9 in the final culture medium: 2% v/v (final concentration in the 3 hour treatment in the presence of S9 mix)

- quality controls of S9 (e.g., enzymatic activity, sterility, metabolic capability): Not specified
Test concentrations with justification for top dose:
I] Range finding experiment (01): The test material was prepared in DMSO at 150.0 mg/mL. It was then prepared in a dilution series, typically with a 1.25-fold dilution factor and the nominal concentrations were:

2.162, 2.702, 3.378, 4.222, 5.278, 6.597, 8.246, 10.31, 12.88, 16.11, 20.13, 25.17, 31.46, 39.32, 49.15, 61.44, 76.80, 96.00, 120.0, and 150.0 mg/mL

II] Mutation Experiment 01 (3-hour treatments): Based on findings in the Range Finder Experiment 01, for the Main Experiment 01 the test material was prepared in DMSO at 31.46 mg/mL for the 3 hour -S9 treatment schedule and at 150.0 mg/mL for the 3 hour +S9 treatment schedule. It was then prepared in an appropriate dilution scheme (based upon the Range Finder results). The test material was finally diluted for treatment by adding 200 μL to 20 mL of appropriate tissue culture medium containing 1 × 10˄7 cells. The nominal concentrations of the test material were:

-S9: 3.762, 7.524, 15.05, 16.72, 18.58, 20.64, 22.93, 25.48, 28.31, and 31.46 mg/mL

+S9: 1.920, 3.840, 7.680, 15.36, 30.72, 61.44, 76.80, 96.00, 108.0, 120.0, and 150.0 mg/mL

III] Mutation Experiment 02 (3-hour treatments): Based on findings in the Range Finder Experiment 01 and the Main Experiment 01, for the Main Experiment 02 the test material was prepared in DMSO at 31.46 mg/mL for the 3 hour –S9 treatment schedule and at 150.0 mg/mL for the 3 hour +S9 treatment schedule was then prepared in an appropriate dilution scheme (based upon the Range Finder and Main Experiment 01 results). The test material was finally diluted for treatment by adding 200 μL to 20 mL of appropriate tissue culture medium containing 1 × 10˄7 cells. The nominal concentrations of the test material were:

-S9: 3.998, 7.997, 8.885, 9.872, 10.97, 12.19, 13.54, 15.05, 16.72, 18.58, 20.64, 22.93, 25.48, 28.31 and 31.46 mg/mL

+S9: 1.920, 3.840, 7.680, 15.36, 30.72, 61.44, 76.80, 96.00, 108.3, 114.0, 120.0 and 150.0 mg/mL
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Dimethyl sulfoxide DMSO (1%)

- Justification for choice of solvent/vehicle: DMSO was selected as the test material was found to be easily soluble when diluted in it and it is a well-established solvent. The solutions were prepared on the day of use and cultures were treated within two hours of formulation.

- Justification for percentage of solvent in the final culture medium: Not specified
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
cyclophosphamide
Details on test system and experimental conditions:
NUMBER OF REPLICATIONS:
- Number of cultures per concentration (single, duplicate, triplicate) : Duplicate
- Number of independent experiments : 2 (Mutation experiment 01 and 02)

METHOD OF TREATMENT/ EXPOSURE:
- Cell density at seeding (if applicable): 1 x 10˄7 in 20 mL (3 hour experiments)
- Test substance added in medium

TREATMENT AND HARVEST SCHEDULE:
- Exposure duration/duration of treatment: 3 hours

FOR GENE MUTATION:
- Expression time (cells in growth medium between treatment and selection): 48 hours
- Selection time (if incubation with a selective agent): 2 days
- Fixation time (start of exposure up to fixation or harvest of cells): 12 to 14 days
- Method used: microwell plates for the mouse lymphoma assay.
- If a selective agent is used, indicate its identity, its concentration and, duration and period of cell exposure.: Trifluorothymidine (TFT)
- Number of cells seeded and method to enumerate numbers of viable and mutants cells: 1 x 10˄7 in 20 mL (3 hour experiment).
- Criteria for small (slow growing) and large (fast growing) colonies: A colony was assessed to be large if it covered one quarter or more of the area of the well. If a well contained both a small and large colony, this was scored as a well containing a small colony.

METHODS FOR MEASUREMENT OF CYTOTOXICITY
- Method, e.g.: relative total growth (RTG)
- Any supplementary information relevant to cytotoxicity: RTG was used as the definitive measure of cytotoxicity in the mutation assay, and was the product of RSG and Relative cloning efficiency (RCE). RCE was a measure of viability at the time of selection for TFT resistant mutants in an individual culture. RCE was the CE expressed as a percentage of the mean control CE in non-selective medium (viable plates).

Relative cloning efficiency (RCE):

%RCE = (CE / Mean control CE) x 100

Relative total growth (RTG):

%RTG= (% RSG x % RCE) / 100

METHODS FOR MEASUREMENTS OF GENOTOXICITY :
Preliminary cytotoxicity test (Range finder)

In the range finder test (01), single cultures were treated with a number of concentrations of test material and the cell counts were used to calculate Relative Suspension Growth (RSG), the resulting values i.e., those best covering a cytotoxicity range (if applicable), were used to select concentrations to use on the main mutation assay. There were two solvent control cultures and no positive controls tested for each treatment. Cultures were not plated for the range finder experiment.

Mutation assay (Microwell method)
In each mutation assay (01 and 02 – 3 hour treatments), duplicate cultures were treated with a number of concentrations of test material and the most appropriate i.e., best covering a cytotoxicity range (if applicable) of 10% to 90% RSG, were sampled for CE (viability) and TFT resistance. There were four solvent control cultures and two positive control cultures tested for each treatment. In tests using 3 hours exposure, 1 x 10˄7 cells were treated in 20 mL medium containing approximately 2.5% serum.

At the end of exposure period, the cells were maintained in exponential growth for an expression period of approximately 48 hours before cloning in 96-well microtitre plates. Each culture was cloned on two selective (for TFT resistance) and two non-selective (for viability) plates with 2000 and 1.6 cells per well, respectively.

To demonstrate the mutability of the cells, 4-nitroquinoline-1-oxide (4NQO) was included as the positive control in the mutation assays without metabolic activation (-S9). Cyclophosphamide (CPA) was included in the mutation assay with metabolic activation (+S9) for the same reason and also to demonstrate the efficacy of the S9-cofactor mix. In addition, since CPA is known to cause chromosomal damage (resulting in small colonies) as well as to point mutations, its use should demonstrate the sensitivity of the test system to clastogens.

In all cases, duplicate cultures were treated with a single positive control concentration in dimethyl sulphoxide (DMSO) at a volume of 1% of the exposure medium. The use of DMSO at this level has been shown previously to be acceptable and is customarily used in this test system.

The mutant frequency (MF) for each treatment was calculated:

MF for each culture was calculated from the proportion of wells without colonies in selective medium plates, P(0)MF. It was corrected for viability using CE (above) calculated from the proportion of wells without colonies in nonselective medium, P(0)CE. Where the selective medium plates were seeded with 2000 cells per well, and the non-selective medium plates with 1.6 cells per well:

MF P (0) = (Total number of wells – number of wells with a colony) / Total number of wells

Individual MF = (−ln P(0) Mutant Plates / 2000 x (Viability (CE)) / 100)) x 1000,000

Average MF (pooled) = (MF total for that treatment condition / Total number of replicates for that treatment condition)

Induced Mutant Frequency (IMF) calculations:

Pooled IMF = Mean MF of replicate culture (test substance) - Mean MF of control

Pooled IMF small = Mean small MF of replicate culture (test substance) - Mean small IMF of control

IMF small colonies % = (IMF (small) of replicate culture (test substance) / IMF of pooled cultures (test substance)) x100
Evaluation criteria:
I] Criteria for conclusion of a clearly positive result:
The criteria for concluding that an individual test is clearly positive was:
a) the MF at one or more concentrations is at least 126 x 10˄-6 greater than the concurrent solvent control (GEF) and
b) there is a significant dose-relationship as indicated by trend test analysis and
c) any positive results obtained at less than 10% RTG are excluded

The positive control cultures mutant frequency values should approximate those of the acceptable ranges from the Test Facility’s historical control database.

II] Criteria for conclusion of a clearly negative result:
The criterion for concluding that an individual test is negative (considered non-mutagenic) will be:
a) The GEF is not exceeded at any test substance concentration.
b) There is no concentration related increase. A trend test will be conducted if the GEF is exceeded or if the Study Director feels that it may aid in the interpretation of a possible concentration related increase that may be just below the GEF.
Statistics:
Please see 'Any other information on materials and methods incl. tables' for information on Statistics.'
Key result
Species / strain:
mouse lymphoma L5178Y cells
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
True negative controls validity:
not specified
Positive controls validity:
valid
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
There were no remarkable changes in osmolality or pH observed between the solvent controls and test concentrations evaluated using an osmometer and pH meter, respectively.

RANGE-FINDING/SCREENING STUDIES:

Treatment schedule: 3 hours in the absence of metabolic activation (-S9)
The concentration range tested was 21.62 to 1500 μg/mL. Upon addition of test material to the culture medium, precipitate was observed at a concentration of 491.5 μg/mL and above. At the end of the treatment period, precipitate was observed at a concentration of 1500 μg/mL and above. Cytotoxicity (identified as a reduction in RSG of less than 10%) was observed at a concentration of 314.6 μg/mL and above. Lower concentrations of 251.7, 201.3, 161.1, 128.8, 103.1, 82.46, 65.97, 52.78, 42.22, 33.78, 27.02 and 21.62 μg/mL yielded mean RSG values of 28, 78, 94, 94, 94, 100, 100, 100, 94, 100, 94, and 94%, respectively.

Treatment schedule: 3 hours in the presence of metabolic activation (+S9)
The concentration range tested was 21.62 to 1500 μg/mL. Upon addition of test material to the culture medium, precipitate was observed at a concentration of 491.5 μg/mL and above. At the end of the treatment period, precipitate was observed at a concentration of 1500 μg/mL. Cytotoxicity (identified as a reduction in RSG of less than 10%) was observed at a concentration of 1500 μg/mL. Lower concentrations of 1200, 960.0, 768.0, 614.4, 491.5, 393.2, 314.6, 251.7, 201.3, 161.1, 128.8, 103.1, 82.46, 65.97,52.78, 42.22, 33.78, 27.02 and 21.62 μg/mL yielded mean RSG values of 11, 32, 47, 63, 68, 63, 58, 68, 63, 68, 74, 79, 84, 79, 79, 84, 89, 89, and 95%, respectively.

STUDY RESULTS
- Concurrent vehicle negative and positive control data:

The mean solvent control (DMSO) suspension growth, cloning efficiency, and mutant frequency were consistent with those stated in the OECD guideline (490) and current historical control data. The results obtained with positive control agents demonstrated the ability of the test system to identify mutagens and clastogens and where appropriate, the ability of the S9 mix to metabolise cyclophosphamide.

Main Mutagenicity Experiments:

Experiment 1: Treatment schedule: 3 hours in the absence of metabolic activation (-S9):
The concentration range tested was 37.62 to 314.6 μg/mL. Upon addition of test item to the culture medium, precipitate was observed at a concentration of 229.3 μg/mL and above. At the end of the treatment period, no precipitate was observed at any concentration tested.

A mean RSG value of 12% was observed at a concentration of 314.6 μg/mL. Lower concentrations of 283.1, 254.8, 229.3, 206.4, 185.8, 167.2, 150.5, 75.24and 37.62 μg/mL yielded mean RSG values of 1, 25, 17, 16, 3, 6, 12, 103, and 102%, respectively. Due to variability and lack of coverage in the RSG values, if plated it was unlikely that the RTG values would have covered the cytotoxicity range, from that producing cytotoxicity and including concentrations at which there is moderate and little or no cytotoxicity. Therefore, the cultures were discarded and further testing was conducted.

Experiment 2: Treatment schedule: 3 hours without metabolic activation (-S9):
The concentration range tested was 39.98 to 314.6 μg/mL. Upon addition of test item to the culture medium, precipitate was observed at a concentration of 206.4 μg/mL and above. At the end of the treatment period, no precipitate was observed at any concentration tested.

A mean RSG value of 1% was observed at a concentration of 314.6 μg/mL. Lower concentrations of 283.1, 254.8, 229.3, 206.4, 185.8, 167.2, 150.5, 135.4, 121.9, 109.7, 98.72, 88.85, 79.97 and 39.98 μg/mL yielded mean RSG values of 1, 2, 3, 3, 5, 8, 10, 17, 32, 41. 65. 67. 78 and 97%, respectively. The following concentrations were selected for plating 150.5, 135.4, 121.9, 109.7, 98.72, 79.97, and 39.98 μg/mL. A mean RTG value of 8% (cytotoxicity of 92%) was observed at a concentration of 150.5 μg/mL. Lower concentrations of 135.4, 121.9, 109.7, 98.72, 79.97, and 39.98 μg/mL yielded mean RTG values of 11, 25, 32, 57, 78, and 101%, respectively.

Data for the SG, CE, and MF in the solvent control of the 3 hour treatment without S9 mix were consistent with those stated in the OECD guideline and the MF was consistent with the test facility’s historical control database (based on 95% confidence limits) for L5178Y cells and therefore, the acceptance criteria were met. Data for the small colony IMF (174 x 10˄-6) in the 4NQO positive control result of the 3 hour treatment without S9 mix were consistent with the acceptance criteria stated in the OECD guidelineand the test facility’s historical control database and a mean RTG value of 87% was observed. The mutant frequencies of the test item did not exceed the GEF at any concentrations analysed. As no concentration came close to meeting or exceeding the GEF a trend-test was not conducted as there was no apparent evidence of a relevant concentration related increase in mutant frequency. The criteria for a clear negative result were met.

Experiment 1: Treatment schedule: 3 hours with metabolic activation (+S9):
The concentration range tested was 19.20 to 1500 μg/mL. Upon addition of test item to the culture medium, precipitate was observed at a concentration of 1080 µg/mL and above. At the end of the treatment period, no precipitate was observed at any concentration tested.

A mean RSG value of 76% was observed at a concentration of 1500 μg/mL. Lower concentrations of 1200, 1080, 960, 768.0, 614.4, 307.2, 153.6, 76.80, 38.40, and 19.20 μg/mL yielded mean RSG values of 11, 46, 58, 78, 80, 84, 89, 86, 93, and 97%, respectively. Due to the lack of cytotoxicity observed at the top dose (1500 µg/mL), leading to inconsistencies in RSG values and the dose response, the cultures were discarded and further testing was conducted.

Experiment 2: Treatment schedule: 3 hours with metabolic activation (+S9):

The concentration range tested was 19.20 to 1500 μg/mL. Upon addition of test item to the culture medium, precipitate was observed at a concentration of 614.4 µg/mL and above. At the end of the treatment period, no precipitate was observed at any concentration tested.

A mean RSG value of 2% was observed at a concentration of 1500 μg/mL. Lower concentrations of 1200, 1140, 1083, 960.0, 768.0, 614.4, 307.2, 153.6, 76.80, 38.40, and 19.20 μg/mL yielded mean RSG values of 3, 5, 8, 14, 33, 56, 68, 70, 81, 89, and 89%, respectively. The following concentrations were selected for plating 1200, 960.0, 768.0, 614.4, 307.2 and 38.40 μg/mL.

A mean RTG of 1% (cytotoxicity of 99%) was observed at a concentration of 1200 μg/mL. Lower concentrations of 960.0, 768.0, 614.4, 307.2, and 38.40 μg/mL gave RTG values of 10, 26, 54, 64, and 101%, respectively. However, the concentration 1200 µg/mL was excluded as the RTG was below 10%, in accordance with the OECD guideline. Furthermore, a high CE value for a 38.40 µg/mL culture was recorded, this was thought to be due to a sampling error when preparing the cell suspension for plating. Therefore, this culture was excluded from the data analysis; this is deemed as acceptable as single cultures can be dosed in accordance with the OECD guidelines and will not impact the validity and integrity of the study.

Data for the SG, CE and MF in the solvent control of the 3 hour treatment with S9 mix were consistent those stated in the OECD guideline and the MF was consistent with the test facility’s historical control database (based on 95% confidence limits) for L5178Y cells and therefore, the acceptance criteria were met. Data for the small colony IMF (507x10-6) in the CPA positive control result of the 3 hour with S9 mix were consistent with the acceptance criteria stated in the OECD guideline. The CPA mutant frequency (1416x10-6) was higher than the upper 95% confidence limits of the historical positive control (165-1342 x10˄-6), however this was considered acceptable since it demonstrated a positive response could be induced. A mean RTG value of 52% was observed for the CPA. The mutant frequencies of the test item did not exceed the GEF at any concentrations analysed. As no concentration came close to meeting or exceeding the GEF a trend-test was not conducted as there was no apparent evidence of a relevant concentration related increase in mutant frequency The criteria for a clear negative result were met.

There was no indication of a requirement to conduct testing for 24 hours without S9, as outlined in the OECD guideline. Namely, the test item was readily soluble and is not known to be of a class of substances that require longer exposure times to be detected (e.g. a nucleoside analogue). Further testing with a 24 hours without S9 treatment schedule was not required for this test item, this has no impact on the validity and integrity of this study.

HISTORICAL CONTROL DATA (with ranges, means and standard deviation, and 95% control limits for the distribution as well as the number of data)
- Positive historical control data: Please see 'Table 4' in 'Any other information on results incl. tables' for information on historical control data.
- Negative (solvent/vehicle) historical control data: Please see 'Table 4' in 'Any other information on results incl. tables' for information on historical control data.

Table 2. Summary of Analysed Concentrations

Exposure Condition

Test Material Concentration

(µg/mL)

RTG%*

SG*

CE%*

X 10-6

IMF Small Colonies%*

(MF) Historical control data 95% confidence limits

MF*

IMF

(pooled all colonies)*

IMF

(small colonies)*

3 hour

(-S9 mix)

Experiment 02

Solvent (DMSO)

100

18

111

98

0

0

0

58 to 111

GEF Threshold

N/A

N/A

N/A

224

N/A

N/A

N/A

N/A

39.98

101

18

116

83

-15

1

79.97

78

14

111

82

-16

-5

98.72

57

12

97

101

3

13

109.7

32

7

86

103

4

15

121.9

25

6

88

133

35

32

135.4

11

3

74

188

90

43

150.5

8

2

83

168

70

21

4NQO 0.19

87

18

97

562

464

174

38

445 to 1044

 

3 hour

(+S9 mix)

Experiment 02

Solvent (DMSO)

100

21

108

113

0

0

0

54 to 115

GEF Threshold

N/A

N/A

N/A

239

N/A

N/A

N/A

N/A

38.40

101

19

123

87

-26

-4

307.2

64

14

101

132

19

0

614.4

54

12

104

184

71

32

768.0

26

7

83

195

82

44

960.0

10

3

78

195

82

43

1200 E

1

1

22

277

164

52

CPA 2.79

52

17

68

1416

1303

507

39

165 to 1342

Key: conc. = Concentration

RTG = Relative Total Growth

SG = Suspension Growth

CE = Cloning Efficiency

MF = Mutant Frequency

IMF = Induced Mutant Frequency

N/A = Not applicable

4NQO = 4-Nitroquinoline

CPA = Cyclophosphamide

* = mean values

E = Excluded as RTG below 10%

GEF = global evaluation factor (126x10-6).

The GEF was not exceeded for any concentration tested

Table 3. Osmolality and pH Measurements at the end of each Treatment (Experiment 01)

Timepoint

Osmolality (mOsm/kg)

pH

3 hour (-S9)

DMSO

314.6 µg/mL

DMSO

314.6 µg/mL

433

430

7.36

7.36

3 hour (+S9)

DMSO

1500 µg/mL

DMSO

1500 µg/mL

442

439

7.26

7.29

Table 4. Historical Control Data

Control

Concentration

Metabolic

Activation

Treatment

Range of Mutant Frequency (within database) Min to Max

Mean

Standard Deviation

95% Confidence Limits

Number of data points

Solvent (vehicle)

1% DMSO

-

3h

62 to 105

85

14

58 to 111

13

4-Nitroquinoline-1-oxide

0.001 mM

(1 µM)

-

3h

519 to 1069

745

153

445 to 1044

13

Solvent
(vehicle)

1% DMSO

+

3h

54 to 112

85

15

54 to 115

13

Cyclophosphamide

0.01 mM

(10 µM)

+

3h

417 to 1581

753

300

165 to 1342

13

Data generated:

3h -S9 mix from 25 July 2017 to 04 May 2021

3h +S9 mix from 08 December 2015 to 04 May 2021

Conclusions:
Petroleum Gas Oil fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal origin (EC 941-364-9) was not mutagenic in the mouse lymphoma L5178Y Tk locus assay in the absence and presence of S9 mix, and under the test conditions used.
Executive summary:

In a key in vitro mammalian cell gene mutation assay, the potential of the test material (Petroleum Gas Oil fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal origin (EC 941-364-9)) to induce forward mutation at the thymidine kinase (Tk) locus in mouse lymphoma L5178Y TK+/-3.7.2 C cells was evaluated. Treatment concentrations for the mutation assays were selected on the basis of the result of a range-finding preliminary cytotoxicity test.

The test material was applied to the test system under two treatment schedules: treatment for 3 hours in the absence and presence of an in vitro activation system based on S9 fraction obtained from Aroclor 1254-induced rat liver (S9 mix). Dimethyl sulphoxide (DMSO) was used as vehicle in this study.

The following test material concentrations were examined in the mutation assays:

Range finding experiment:

21.62, 29.02, 33.78, 42.22, 52.78, 65.97, 82.46, 103.1, 128.8, 161.1, 201.3, 251.7, 314.6, 393.2, 491.5, 614.4, 768.0, 960.0, 1200, 1500 μg/mL.

Main Mutation Experiment 01 (3-hour treatment):

(-S9): 39.98 to 314.6 μg/mL

(+S9): 19.20 to 1200 μg/mL

Data for the suspension growth (SG), CE and Mutant Frequency (MF) in the solvent control for all treatment schedules were consistent with those stated in the OECD guideline and the MF was consistent with the test facility’s historical control database (based on 95% confidence limits) for L5178Y cells and therefore, the acceptance criteria were met. The positive control results for all treatment schedules were consistent with the acceptance criteria stated in the OECD guideline.

In Experiment 02, 3-hour -S9 treatment exposure: a concentration of 150.5 µg/mL gave 8% relative total growth (RTG) (cytotoxicity of 92%). In Experiment 02, 3-hour +S9 treatment exposure: a concentration of 960.0 µg/mL gave 10% RTG (cytotoxicity of 90%).

In final mutation assay experiments, upon addition of the test item to the culture medium, precipitate was observed at a concentration of 206.4 µg/mL and above in the 3h –S9 mix treatment schedule and at a concentration of 614.4 µg/mL and above in the 3h +S9 mix treatment schedule. At the end of the treatment period, no precipitate was observed in either treatment schedule.

No relevant changes in mutant frequency (MF) were observed for any of the treatment schedules at any of the concentrations analysed. The Global Evaluation Factor (GEF) was not exceeded for any of the test concentrations analysed and the criteria for a clear negative response were met for all treatment schedules.

Under the test conditions used, Petroleum Gas Oil fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal origin (EC 941-364-9) was not mutagenic in the mouse lymphoma L5178Y Tk locus assay in the absence and presence of S9 mix.

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Genetic toxicity in vivo

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

In Vitro

In vitro Gene Mutation in Bacterial Cells

 

Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) was tested for mutagenic activity using genetically modified Salmonella typhimurium LT2 bacteria of strains TA1535, TA1537, TA98 and TA100, and Escherichia coli WP2 strain uvrA/pKM101 as indicator organisms, according to the methods of Maron and Ames, 1983, Venitt et al, 1984, Mortelmans and Zeiger, 2000 and Mortelmans and Riccio, 2000 (Mee, 2020).

 

A preliminary solubility test was conducted. Dimethyl sulphoxide was found to be suitable and was therefore used throughout this study as the solvent for the test item.

 

A mutagenicity test was conducted for Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) using the plate incorporation method (Test 1) for all five indicator strains in both the presence and absence of an in vitro activation system based on S9 fraction obtained from Aroclor 1254-induced rat liver (S9 mix). The dose range used was 1.6 to 5000μg per plate. As the result of Test 1 was clearly negative, a confirmatory test was carried out using the liquid pre-incubation method, Test 2, using a dose range of 1.6 to 5000μg per plate in the presence and absence of S9 mix.

 

The test item showed evidence of cytotoxicity. The minimum dose level at which cytotoxicity was seen was 500μg per plate. The maximum dose level scored for revertant colonies was 5000μg per plate. The minimum dose level at which precipitate was seen on the test plates was 1600μg per plate.

 

No significant increase in numbers of revertant (histidine or tryptophan-independent) colonies was seen with any of the five indicator strains either in the presence or absence of S9 mix.

 

It was concluded that Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) was not mutagenic for Salmonella typhimurium LT2 strains TA1535, TA1537, TA98 and TA100, and Escherichia coli WP2 strain uvrA/pKM101, either in the presence or absence of S9 mix, when tested under the conditions used in this assay.

 

In vitro Micronucleus Assay in Mammalian Cells

 

Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) was tested for its potential to induce micronucleus formation in the in vitro micronucleus test with manual scoring on microscope slides. In all tests none of the treatment schedules resulted in significant increases in micronucleus formation in test item treated cultures. It was concluded that Petroleum Gas Oil Fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal Origin (EC 941-364-9) did not induce the formation of micronuclei (MN) in human lymphocytes in the absence and presence of S9, under the test conditions used.The criteria for a negative response was met. (Clare, 2021)

 

In vitro Gene Mutation in Mammalian Cells

 

In a key in vitro mammalian cell gene mutation assay (Clare, 2022), the potential of the test material (Petroleum Gas Oil fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal origin (EC 941-364-9)) to induce forward mutation at the thymidine kinase (Tk) locus in mouse lymphoma L5178Y TK+/-3.7.2 C cells was evaluated. Treatment concentrations for the mutation assays were selected on the basis of the result of a range-finding preliminary cytotoxicity test.

 

The test material was applied to the test system under two treatment schedules: treatment for 3 hours in the absence and presence of an in vitro activation system based on S9 fraction obtained from Aroclor 1254-induced rat liver (S9 mix). Dimethyl sulphoxide (DMSO) was used as vehicle in this study.

 

The following test material concentrations were examined in the mutation assays:

 

Range finding experiment:

21.62, 29.02, 33.78, 42.22, 52.78, 65.97, 82.46, 103.1, 128.8, 161.1, 201.3, 251.7, 314.6, 393.2, 491.5, 614.4, 768.0, 960.0, 1200, 1500μg/mL.

 

Main Mutation Experiment 01 (3-hour treatment):

(-S9): 39.98 to 314.6 μg/mL

(+S9): 19.20 to 1500μg/mL

 

Data for the suspension growth (SG), CE and Mutant Frequency (MF) in the solvent control for all treatment schedules were consistent with those stated in the OECD guideline and the MF was consistent with the test facility’s historical control database (based on 95% confidence limits) for L5178Y cells and therefore, the acceptance criteria were met. The positive control results for all treatment schedules were consistent with the acceptance criteria stated in the OECD guideline.

 

In Experiment 02, 3-hour -S9 treatment exposure: a concentration of 150.5 µg/mL gave 8% relative total growth (RTG) (cytotoxicity of 92%). In Experiment 02, 3-hour +S9 treatment exposure: a concentration of 960.0 µg/mL gave 10% RTG (cytotoxicity of 90%).

 

In final mutation assay experiments, upon addition of the test item to the culture medium, precipitate was observed at a concentration of 206.4 µg/mL and above in the 3h –S9 mix treatment schedule and at a concentration of 614.4 µg/mL and above in the 3h +S9 mix treatment schedule. At the end of the treatment period, no precipitate was observed in either treatment schedule.

 

No relevant changes in mutant frequency (MF) were observed for any of the treatment schedules at any of the concentrations analysed. The Global Evaluation Factor (GEF) was not exceeded for any of the test concentrations analysed and the criteria for a clear negative response were met for all treatment schedules.

 

Under the test conditions used, Petroleum Gas Oil fraction, Co-processed with Renewable Hydrocarbons of Plant and/or Animal origin (EC 941-364-9) was not mutagenic in the mouse lymphoma L5178Y Tk locus assay in the absence and presence of S9 mix.

Read-across

It is noted that any supporting genotoxic robust study summaries for read-across substances are all available in the Concawe VHGO dossiers for those substances. For clarity reasons, where data are available on “Petroleum gas oil fraction, co-processed with organic substances of plant and/or animal origin” (EC 941-364-9), the dossier isfocused on data generated on the substance itself andthere is referenceto those robust study summaries in the Concawe dossiers for the remaining read across data which are part of the WoE

Justification for classification or non-classification

Some oil products containing relatively high concentrations of polycyclic aromatic compounds (PAC) are considered genotoxic carcinogens, and, consequently, are classified and labelled as carcinogenic, Cat. 1A or 1B (H350) or Cat. 2 (H351) according to the EU CLP Regulation (EC) 1272/2008. This classification as carcinogenic does not automatically imply that these substances need also to be classified as mutagenic as defined by the CLP Regulation. The EU legislation aims primarily to classify substances as mutagenic if there is evidence of producing heritable genetic damage, i.e. evidence of producing mutations that are transmitted to the progeny or evidence of producing somatic mutations in combination with evidence of the substance or relevant metabolite reaching the germ line cells in the reproductive organs. The PAC in oil products are poorly bioavailable due to their physico-chemical properties (low water solubility and high molecular weight), making it unlikely that the genotoxic constituents can reach and cause damage to germ cells (Roy, 2007; Potter, 1999). Considering their poor bioavailability, oil products which have been classified as carcinogenic do not need to be classified as mutagenic unless there is clear evidence that germ cells are affected by exposure, consistent with the CLP Regulation. For example, based on in vivo micronucleus tests on home heating oil as well as for read-across substances that were all negative for genotoxicity, vacuum gas oils/hydrocracked gas oils/distillate fuels are not classified as mutagens according to the EU CLP Regulation (EC) 1272/2008.