Registration Dossier

Toxicological information

Genetic toxicity: in vitro

Currently viewing:

Administrative data

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:
The experimental phase of this study was performed between 26 May 2010 and 24 June 2010.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
guideline study
Justification for type of information:
REPORTING FORMAT FOR THE ANALOGUE APPROACH
See read-across justification report under Section 13 ‘Assessment Reports’.

1. HYPOTHESIS FOR THE ANALOGUE APPROACH
In accordance with REACH Annex XI, Section 1.5, of Regulation (EC) No. 1907/2006 (REACH) the standard testing regime may be adapted in cases where a grouping or read-across approach has been applied.

The similarities may be based on:
(1) a common functional group
(2) the common precursors and/or the likelihood of common breakdown products via physical or biological processes, which result in structurally similar chemicals; or
(3) a constant pattern in the changing of the potency of the properties across the category

The source substance and the target substance are considered to be similar enough to facilitate read-across for the following reasons:
1. Both substances show low systemic toxicity in in vivo studies. A number of studies are provided to show that monovalent potassium and/or sodium inorganic orthophosphates exhibit low systemic toxicity via the oral route for both acute exposure and repeated dose exposure.
2. Substance similarities: Both salts are monovalent inorganic phosphates, composed of a phosphate anion and an alkali metal cation. Both the Na+ and the K+ cation have a similar biological function and therefore orthophosphate salts of these types are not considered to differ in their systemic toxicity profile; differences arise in their local effects profile due to the increasing or decreasing acidity of the substances. This has been shown not to have an effect on the systemic toxicity profile of the substances, thus suggesting that they are metabolized via similar metabolic pathways and to similar breakdown products.
Justification for no further testing for genetic toxicity: As sodium and potassium phosphates are routinely used in the nutrient broths that support bacterial colonies in the laboratory and as such bacteria are constantly exposed to these inorganic phosphates. In addition, sodium orthophosphates are also found in the metabolic activation mixture (e.g. S9-mix) which is used in an AMES test to determine whether a test chemical can be metabolized within the body to produce a compound that may be genotoxic. The constant exposure of bacteria to these materials suggests that they pose no inherent risk of genotoxicity. In addition the Na+, K+ and PO43- ions are essential for life and are not considered to be genotoxic or mutagenic in standard test systems.

2. SOURCE AND TARGET CHEMICAL(S) (INCLUDING INFORMATION ON PURITY AND IMPURITIES)
See read-across justification report under Section 13 ‘Assessment Reports’.

3. ANALOGUE APPROACH JUSTIFICATION
See read-across justification report under Section 13 ‘Assessment Reports’.

4. DATA MATRIX
See read-across justification report under Section 13 ‘Assessment Reports’

Cross-reference
Reason / purpose:
read-across: supporting information

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Deviations:
no
Qualifier:
according to
Guideline:
JAPAN: Guidelines for Screening Mutagenicity Testing Of Chemicals
Deviations:
no
Qualifier:
equivalent or similar to
Guideline:
EPA OPPTS 870.5100 - Bacterial Reverse Mutation Test (August 1998)
Version / remarks:
Meets the requirements of the Japanese Regulatory Authorities including METI, MHLW and MAFF, OECD Guidelines for Testing of Chemicals No. 471 "and the USA, EPA (TSCA) OPPTS harmonised guidelines.
Deviations:
no
GLP compliance:
yes (incl. certificate)
Type of assay:
bacterial reverse mutation assay

Test material

Reference
Name:
Unnamed
Type:
Constituent
Type:
Constituent
Details on test material:
Sponsor's identification: PHOSPHORIC ACID TECHNICAL GRADE
Description : Clear colourless slightly viscous liquid
Purity : 85.01%
Batch number : HU10009
Date received : 05 May 2010
Expiry date : Not supplied
Storage conditions: Room temperature in the dark

Method

Target gene:
Histidine for Salmonella.
Tryptophan for E.Coli
Species / strainopen allclose all
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
Not applicable.
Additional strain / cell type characteristics:
not applicable
Species / strain / cell type:
E. coli WP2 uvr A
Details on mammalian cell type (if applicable):
Not applicable.
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
phenobarbitone/beta­naphthoflavone induced rat liver, S9
Test concentrations with justification for top dose:
Preliminary Toxicity Test: 0, 0.15, 0.5, 1.5, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate
main test:
Experiment one: 50, 150, 500, 1500 and 5000 µg/plate
Experiment two: 50, 150, 500, 1500 and 5000 µg/plate
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: Sterile distilled water.
- Justification for choice of solvent/vehicle: The test material was fully miscible in sterile distilled water at 50 mg/ml in solubility checks performed in house. Sterile distilled water was therefore selected as the vehicle.
Controlsopen allclose all
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA100
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 1 µg/plate
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA1535
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 2 µg/plate
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA1537
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 2 µg/plate
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of WP2uvrA
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
other: 2-Aminoanthracene: 10 µg/plate
Remarks:
With S9 mix
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA98
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water
True negative controls:
no
Positive controls:
yes
Positive control substance:
benzo(a)pyrene
Remarks:
With S9 mix Migrated to IUCLID6: Benzo(a)pyrene: 5 µg/plate
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA98
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water
True negative controls:
no
Positive controls:
yes
Positive control substance:
4-nitroquinoline-N-oxide
Remarks:
without S9 mix Migrated to IUCLID6: 4-Nitroquinoline-1-oxide: 0.2 µg/plate
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA1537
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water.
True negative controls:
no
Positive controls:
yes
Positive control substance:
9-aminoacridine
Remarks:
without S9 mix Migrated to IUCLID6: 9-Aminoacridine: 80 µg/plate
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA100
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water.
True negative controls:
no
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
without S9 mix Migrated to IUCLID6: N-ethyl-N'-nitro-N-nitrosoguanidine: 3 µg/plate
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of TA1535
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
Without S9 mix Migrated to IUCLID6: N-ethyl-N'-nitro-N-nitrosoguanidine: 5 µg/plate
Untreated negative controls:
yes
Remarks:
Spontaneous mutation rates of WP2uvrA
Negative solvent / vehicle controls:
yes
Remarks:
Sterile distilled water
True negative controls:
not specified
Positive controls:
yes
Positive control substance:
N-ethyl-N-nitro-N-nitrosoguanidine
Remarks:
Without S9 mix Migrated to IUCLID6: N-ethyl-N'-nitro-N-nitrosoguanidine: 2 µg/plate
Details on test system and experimental conditions:
Test Procedure
Preliminary Toxicity Test
In order to select appropriate dose levels for use in the main test, a preliminary test was carried out to determine the toxicity of the test material. The concentrations tested were 0, 0.15, 0.5, 1.5, 5, 15, 50, 150, 500, 1500 and 5000 µg/plate. The test was performed by mixing 0.1 ml of bacterial culture (TA100 or WP2uvrA-), 2 ml of molten, trace histidine or tryptophan supplemented, top agar, 0.1 ml of test material formulation and 0.5 ml of S9-mix or phosphate buffer and overlaying onto sterile plates of Vogel-Bonner Minimal agar (30 ml/plate). Ten concentrations of the test material formulation and a vehicle control (sterile distilled water) were tested. In addition, 0.1 ml of the maximum concentration of the test material and 2 ml of molten, trace histidine or tryptophan supplemented, top agar were overlaid onto a sterile Nutrient agar plate in order to assess the sterility of the test material. After approximately 48 hours incubation at 37°C the plates were assessed for numbers of revertant colonies using a Domino colony counter and examined for effects on the growth of the bacterial background lawn.

Mutation Test - Experiment 1
Five concentrations of the test material (50, 150, 500, 1500 and 5000 µg/plate) were assayed in triplicate against each tester strain, using the direct plate incorporation method.
Measured aliquots (0.1 ml) of one of the bacterial cultures were dispensed into sets of test tubes followed by 2.0 ml of molten, trace histidine or tryptophan supplemented, top agar, 0.1 ml of the test material formulation, vehicle or positive control and either 0.5 ml of S9-mix or phosphate buffer. The contents of each test tube were mixed and equally distributed onto the surface of Vogel-Bonner Minimal agar plates (one tube per plate). This procedure was repeated, in triplicate, for each bacterial strain and for each concentration of test material both with and without S9-mix.
All of the plates were incubated at 37°C for approximately 48 hours and the frequency of revertant colonies assessed using a Domino colony counter.

Mutation Test - Experiment 2
The second experiment was performed using fresh bacterial cultures, test material and control solutions. The test material dose range was the same as Experiment 1 (50 to 5000 µg/plate).
The test material formulations and vehicle control were dosed using the pre-incubation method as follows:
Measured aliquots (0.1 ml) of one of the bacterial cultures were dispensed into sets of test tubes followed by 0.5 ml of S9-mix or phosphate buffer and 0.1 ml of the vehicle or test material formulation and incubated for 20 minutes at 37°C with shaking at approximately 130 rpm prior to the addition of 2 ml of molten, trace histidine or tryptophan supplemented, top agar. The contents of the tube were then mixed and equally distributed on the surface of Vogel-Bonner Minimal agar plates (one tube per plate). This procedure was repeated, in triplicate, for each bacterial strain and for each concentration of test material both with and without S9-mix.
The positive and untreated controls were dosed using the standard plate incorporation method described in Section "Mutation Test - Experiment 1".
All of the plates were incubated at 37°C for approximately 48 hours and the frequency of revertant colonies assessed using a Domino colony counter.
Evaluation criteria:
Acceptance Criteria
The reverse mutation assay may be considered valid if the following criteria are met:
All tester strain cultures exhibit a characteristic number of spontaneous revertants per plate in the vehicle and untreated controls. Acceptable ranges are presented in the standard test method section 3 with historical control ranges for 2008 and 2009 in Appendix 2.
The appropriate characteristics for each tester strain have been confirmed, eg rfa cell-wall mutation and pKM101 plasmid R-factor etc.
All tester strain cultures should be in the range of 1 to 9.9 x 109 bacteria per ml.
Each mean positive control value should be at least twice the respective vehicle control value for each strain, thus demonstrating both the intrinsic sensitivity of the tester strains to mutagenic exposure and the integrity of the S9-mix. The historical control ranges for 2008 and 2009 are presented in the attached Appendix 2.
There should be a minimum of four non-toxic test material dose levels.
There should be no evidence of excessive contamination.

Evaluation Criteria
There are several criteria for determining a positive result, such as a dose-related increase in revertant frequency over the dose range tested and/or a reproducible increase at one or more concentrations in at least one bacterial strain with or without metabolic activation. Biological relevance of the results will be considered first, statistical methods, as recommended by the UKEMS (6) can also be used as an aid to evaluation, however, statistical significance will not be the only determining factor for a positive response.
A test material will be considered non-mutagenic (negative) in the test system if the above criteria are not met.
Although most experiments will give clear positive or negative results, in some instances the data generated will prohibit a definitive judgement about the test material activity. Results of this type will be reported as equivocal.
Statistics:
Standard deviation

Results and discussion

Test resultsopen allclose all
Species / strain:
E. coli WP2 uvr A
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity
Remarks:
Tested up to maximum recommended dose of 5000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
no cytotoxicity nor precipitates, but tested up to recommended limit concentrations
Remarks:
Tested up to maximum recommended dose of 5000 µg/plate
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
RESULTS
Preliminary Toxicity Test
The test material was non-toxic to the strains of bacteria used (TA100 and WP2uvrA-). The test material formulation and S9-mix used in this experiment were both shown to be sterile.
The numbers of revertant colonies for the toxicity assay were:


With (+) or without (-)
S9-mix Strain Dose (µg/plate)
0 0.15 0.5 1.5 5 15 50 150 500 1500 5000
- TA100 88 80 111 93 98 86 90 93 76 99 74
+ TA100 98 74 102 88 109 92 80 114 97 90 99
- WP2uvrA- 22 27 18 23 24 19 22 25 21 22 22
+ WP2uvrA- 19 32 30 31 22 23 25 24 22 20 23

Mutation Test
Prior to use, the master strains were checked for characteristics, viability and spontaneous reversion rate (all were found to be satisfactory). The amino acid supplemented top agar and S9‑mix used in both experiments was shown to be sterile. The culture density for each bacterial strain was also checked and considered acceptable. These data are not given in the report.

Results for the negative controls (spontaneous mutation rates) are presented in Table 1 and were considered to be acceptable. These data are for concurrent untreated control plates performed on the same day as the Mutation Test.
The individual plate counts, the mean number of revertant colonies and the standard deviations, for the test material, positive and vehicle controls, both with and without metabolic activation, are presented in Table 2 and Table 3 for Experiment 1 and Table 4 and Table 5 for Experiment 2.
A history profile of vehicle and positive control values for 2008 and 2009 is presented in Appendix 2.
The test material caused no visible reduction in the growth of the bacterial background lawn at any dose level and was, therefore, tested up to the maximum recommended dose level of 5000 µg/plate. No test material precipitate was observed on the plates of any of the doses tested in either the presence or absence of S9-mix.

No significant increases in the frequency of revertant colonies were recorded for any of the strains of bacteria, at any dose level either with or without metabolic activation or exposure method.
All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies thus confirming the activity of theS9-mix and the sensitivity of the bacterial strains.
Remarks on result:
other: all strains/cell types tested
Remarks:
Migrated from field 'Test system'.

Any other information on results incl. tables

Table1              Spontaneous Mutation Rates (Concurrent Negative Controls)

EXPERIMENT 1

Number of revertants (mean number of colonies per plate)

Base-pair substitution type

Frameshift type

TA100

TA1535

WP2uvrA-

TA98

TA1537

96

 

20

 

22

 

16

 

7

 

95

(93)

21

(20)

18

(21)

21

(21)

12

(11)

88

 

18

 

22

 

25

 

13

 

EXPERIMENT 2

Number of revertants (mean number of colonies per plate)

Base-pair substitution type

Frameshift type

TA100

TA1535

WP2uvrA-

TA98

TA1537

89

 

12

 

53

 

18

 

10

 

96

(97)

18

(13)

34

(40)

21

(21)

13

(11)

107

 

10

 

32

 

23

 

11

 

Table 2              Test Results: Experiment 1 – Without Metabolic Activation

Test Period

From: 08 June 2010

To: 11 June 2010

With or without

S9-Mix

Test

substance

concentration

(µg/plate)

Number of revertants (mean number of colonies per plate)

Base-pair substitution type

Frameshift type

TA100

TA1535

WP2uvrA-

TA98

TA1537

-

0

108

92

89

(96)

10.2#

22

29

25

(25)

3.5

23

32

27

(27)

4.5

22

15

27

(21)

6.0

16

14

10

(13)

3.1

-

50

86

99

115

(100)

14.5

26

27

27

(27)

0.6

33

29

27

(30)

3.1

14

21

14

(16)

4.0

10

15

16

(14)

3.2

-

150

107

111

97

(105)

7.2

20

25

24

(23)

2.6

24

30

24

(26)

3.5

20

18

15

(18)

2.5

15

16

13

(15)

1.5

-

500

98

103

102

(101)

2.6

29

21

23

(24)

4.2

32

26

30

(29)

3.1

20

19

18

(19)

1.0

12

7

15

(11)

4.0

-

1500

103

103

117

(108)

8.1

23

20

18

(20)

2.5

27

31

26

(28)

2.6

16

14

22

(17)

4.2

10

15

10

(12)

2.9

-

5000

111

119

112

(114)

4.4

25

19

22

(22)

3.0

29

27

22

(26)

3.6

13

21

19

(18)

4.2

12

13

11

(12)

1.0

Positive

controls

 

S9-Mix

 

-

Name

Concentration

(μg/plate)

No. colonies

per plate

ENNG

ENNG

ENNG

4NQO

9AA

3

5

2

0.2

80

499

514

504

(506)

7.6

306

269

231

(269)

37.5

208

189

240

(212)

25.8

145

145

152

(147)

4.0

559

652

385

(532)

135.5

ENNG N-ethyl-N'-nitro-N-nitrosoguanidine

4NQO 4-Nitroquinoline-1-oxide

9AA    9-Aminoacridine

#        Standard deviation

Table 3              Test Results: Experiment 1 – With Metabolic Activation

Test Period

From: 08 June 2010

To: 11 June 2010

With or without

S9-Mix

Test

substance

concentration

(µg/plate)

Number of revertants (mean number of colonies per plate)

Base-pair substitution type

Frameshift type

TA100

TA1535

WP2uvrA-

TA98

TA1537

+

0

103

103

87

(98)

9.2#

14

14

13

(14)

0.6

26

30

36

(31)

5.0

24

25

31

(27)

3.8

9

14

14

(12)

2.9

+

50

104

110

99

(104)

5.5

13

7

10

(10)

3.0

25

30

31

(29)

3.2

21

18

23

(21)

2.5

10

15

14

(13)

2.6

+

150

119

100

93

(104)

13.5

12

13

14

(13)

1.0

30

34

32

(32)

2.0

23

25

25

(24)

1.2

13

10

7

(10)

3.0

+

500

90

84

92

(89)

4.2

14

14

15

(14)

0.6

30

24

26

(27)

3.1

18

24

29

(24)

5.5

15

11

11

(12)

2.3

+

1500

104

107

100

(104)

3.5

12

9

14

(12)

2.5

35

29

29

(31)

3.5

27

23

33

(28)

5.0

10

15

9

(11)

3.2

+

5000

86

98

84

(89)

7.6

14

14

12

(13)

1.2

30

30

27

(29)

1.7

24

23

32

(26)

4.9

12

9

14

(12)

2.5

Positive

controls

 

S9-Mix

 

+

Name

Concentration

(μg/plate)

No. colonies

per plate

2AA

2AA

2AA

BP

2AA

1

2

10

5

2

405

389

381

(392)

12.2

219

197

229

(215)

16.4

300

323

324

(316)

13.6

202

133

128

(154)

41.4

242

273

216

(244)

28.5

 2AABP#

2AA    2-Aminoanthracene

BP      Benzo(a)pyren

#        Standard deviation

Table 4              Test Results: Experiment 2 – Without Metabolic Activation

Test Period

From: 21 June 2010

To: 24 June 2010

With or without

S9-Mix

Test

substance

concentration

(µg/plate)

Number of revertants (mean number of colonies per plate)

Base-pair substitution type

Frameshift type

TA100

TA1535

WP2uvrA-

TA98

TA1537

-

0

122

107

101

(110)

10.8#

18

9

15

(14)

4.6

30

21

33

(28)

6.2

32

26

20

(26)

6.0

20

19

15

(18)

2.6

-

50

98

122

98

(106)

13.9

15

11

18

(15)

3.5

35

24

42

(34)

9.1

18

20

23

(20)

2.5

9

27

8

(15)

10.7

-

150

84

101

110

(98)

13.2

13

15

8

(12)

3.6

33

25

31

(30)

4.2

27

16

24

(22)

5.7

12

14

18

(15)

3.1

-

500

123

113

122

(119)

5.5

12

8

13

(11)

2.6

25

43

25

(31)

10.4

26

24

35

(28)

5.9

15

10

16

(14)

3.2

-

1500

112

106

97

(105)

7.5

11

13

15

(13)

2.0

33

37

33

(34)

2.3

31

20

23

(25)

5.7

11

14

14

(13)

1.7

-

5000

89

100

101

(97)

6.7

7

8

20

(12)

7.2

35

31

30

(32)

2.6

27

20

21

(23)

3.8

7

9

10

(9)

1.5

Positive

controls

 

S9-Mix

 

-

Name

Concentration

(μg/plate)

No. colonies

per plate

ENNG

ENNG

ENNG

4NQO

9AA

3

5

2

0.2

80

507

430

484

(474)

39.5

466

276

298

(347)

103.9

317

330

301

(316)

14.5

152

157

132

(147)

13.2

2206

2210

2107

(2174)

58.3

ENNG4NQO9AA#

ENNG N-ethyl-N'-nitro-N-nitrosoguanidine

4NQO 4-Nitroquinoline-1-oxide

9AA    9-Aminoacridine

#        Standard deviation

Table 5              Test Results: Experiment 2 – With Metabolic Activation

Test Period

From: 21 June 2010

To: 24 June 2010

With or without

S9-Mix

Test

substance

concentration

(µg/plate)

Number of revertants (mean number of colonies per plate)

Base-pair substitution type

Frameshift type

TA100

TA1535

WP2uvrA-

TA98

TA1537

+

0

102

107

118

(109)

8.2#

16

18

20

(18)

2.0

40

34

43

(39)

4.6

42

27

24

(31)

9.6

20

11

9

(13)

5.9

+

50

99

108

85

(97)

11.6

11

11

13

(12)

1.2

37

37

37

(37)

0.0

26

24

32

(27)

4.2

15

19

10

(15)

4.5

+

150

81

82

95

(86)

7.8

11

9

22

(14)

7.0

44

42

35

(40)

4.7

37

34

22

(31)

7.9

23

13

9

(15)

7.2

+

500

99

108

136

(114)

19.3

19

13

16

(16)

3.0

33

36

35

(35)

1.5

30

23

26

(26)

3.5

13

7

7

(9)

3.5

+

1500

101

76

75

(84)

14.7

14

9

15

(13)

3.2

32

41

34

(36)

4.7

25

25

30

(27)

2.9

10

11

10

(10)

0.6

+

5000

93

77

84

(85)

8.0

14

9

13

(12)

2.6

40

41

41

(41)

0.6

23

31

29

(28)

4.2

9

12

10

(10)

1.5

Positive

controls

 

S9-Mix

 

+

Name

Concentration

(μg/plate)

No. colonies

per plate

2AA

2AA

2AA

BP

2AA

1

2

10

5

2

592

675

673

(647)

47.4

145

132

152

(143)

10.1

299

262

321

(294)

29.8

188

198

246

(211)

31.0

157

166

161

(161)

4.5

 2AABP#

2AA    2-Aminoanthracene

BP      Benzo(a)pyren

#        Standard deviation

Applicant's summary and conclusion

Conclusions:
Interpretation of results (migrated information):
negative

The test material was considered to be non-mutagenic under the conditions of this test.
Executive summary:

Introduction.

The method conforms to the guidelines for bacterial mutagenicity testing published by the major Japanese Regulatory Authorities including METI, MHLW and MAFF. It also meets the requirements of the OECD Guidelines for Testing of Chemicals No. 471 "Bacterial Reverse Mutation Test", Method B13/14 of Commission Regulation (EC) Number 440/2008 of 30 May 2008 and the USA, EPA (TSCA) OPPTS harmonised guidelines.

Methods.

Salmonella typhimurium strains TA1535, TA1537, TA98, TA100 and Escherichia coli strain WP2uvrA-were treated with the test material using both the Ames plate incorporation and pre-incubation methods at five dose levels, in triplicate, both with and without the addition of a rat liver homogenate metabolising system (10% liver S9 in standard co-factors). The dose range was determined in a preliminary toxicity assay and was 50 to 5000 µg/plate in the first experiment. The experiment was repeated on a separate day (pre-incubation method) using the same dose range as Experiment 1, fresh cultures of the bacterial strains and fresh test material formulations.

Results.

The vehicle (sterile distilled water) control plates gave counts of revertant colonies within the normal range. All of the positive control chemicals used in the test induced marked increases in the frequency of revertant colonies, both with or without metabolic activation. Thus, the sensitivity of the assay and the efficacy of the S9-mix were validated.

The test material caused no visible reduction in the growth of the bacterial background lawn at any dose level and was, therefore, tested up to the maximum recommended dose level of 5000 µg/plate. No test material precipitate was observed on the plates at any of the doses tested in either the presence or absence of S9-mix.

No significant increases in the frequency of revertant colonies were recorded for any of the bacterial strains, with any dose of the test material, either with or without metabolic activation or exposure method.

Conclusion.

The test material was considered to be non-mutagenic under the conditions of this test.