Registration Dossier

Administrative data

Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

A series of in vitro studies were conducted to assess the potential mutagenicity of LAS (read across). In the first study (Schoeberl 1993), a bacterial mutagenicity study (Ames test) was conducted using S. typhimurium strains TA 1535, TA 1537, TA 98 and TA 100, as well as TA1538 at test concentrations of 8, 40, 200, 1000 and 5000 μg/plate. All strains tested negative with and without S9 activation.

In the second test (Anon. 1995), the potential of LAS to cause mutations in mammalian cells was examined. Chinese Hamster Ovary (CHO) cells were exposed to concentrations of 0, 0.6, 1, 1.8, 3, and 6 μg/ml without S9, and 0, 6, 10, 18, 30, and 60 μg/ml with S9. The cells were then examined for cytogenicity and mutation frequency. Ethyl methane sulfonate and 3-(20-)methylcholanthrene were used as positive control substances. Preliminary tests show the test substance was cytotoxic at concentrations of 50 μg/ml or greater with metabolic activation, and 100 μg/ml or above without metabolic activation. There was no biologically significant increase in mutation frequency in the treated groups. Therefore, results show that LAS was not mutagenic to CHO cells both in the presence and absence of S9.

The third study (Murie and Innes 1997) examined the potential of LAS to cause chromosomal aberrations in mammalian cells. Chinese hamster ovary cells were exposed to concentrations of 2.5, 5, 10, 15, 20, 26, 33, and 39 μg/ml with S9, and 20, 39, 58, 78, 104, 130, and 156 μg/ml without S9. No biologically significant results were seen in treated cultures in the absence of metabolic activation. In the presence of metabolic activation the results were more equivocal. In the first of three tests, no cytotoxicity, and no increase in chromosome aberrations were observed at doses of 10 or 20 μg/ml and 100% cytotoxicity was observed at 39 μg/ml. In the second test, a steep cytotoxicity curve was observed between 10 and 20 μg/ml with a cell count of 68/90 % at the 10 μg/ml dose and no living cells remaining at the 20 μg/ml dose. An increased in aberration frequency could be observed at the 10 μg/ml dose. No increase in aberration frequency has been observed at lower doses which also did no show any cytotoxicity. To gain clarity on the positive result an additional test was conducted. Here, no cytotoxicity and no increase in chromosomal aberration frequency have been observed at the 10 μg/ml dose. At the 15 μg/ml dose the cell number was reduced to 25 % which is why this dose group cannot be evaluated due to excessive cytotoxicity. These results indicate that LAS is weakly clastogenic at cytotoxic concentrations but negative at concentrations below cytotoxic concentrations in this in vitro assay.

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
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP laboratory study
Qualifier:
according to
Guideline:
EU Method B.13/14 (Mutagenicity - Reverse Mutation Test Using Bacteria)
Principles of method if other than guideline:
Directive 84/449/EEC, B.14 Mutagenicity (Salmonella typhimurium - reverse mutation assay)" 1984; equivalent to OECD 471
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay
Species / strain / cell type:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Details on mammalian cell type (if applicable):
also TA 1538
Metabolic activation:
with and without
Metabolic activation system:
Arochlor-induced S9 fraction
Test concentrations with justification for top dose:
8, 40, 200, 1000 and 5000 ug/plate
Vehicle / solvent:
Water solution at 50 g/L
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
Remarks:
water
True negative controls:
yes
Positive controls:
yes
Remarks:
aminoanthracene
Positive control substance:
other: nitrofluorene, sodium azide and aminoacridine
Species / strain:
S. typhimurium TA 1535, TA 1537, TA 98 and TA 100
Metabolic activation:
with and without
Genotoxicity:
negative
Remarks:
with and without activation
Cytotoxicity / choice of top concentrations:
cytotoxicity
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
TA 1538 also tested negative. During the pre-incubation test, signs of toxicity were noted at concentrations as low as 125 ug/plate. No precipitation of the product was observed at any concentration tested.
Conclusions:
LAS is not mutagenic in the Ames test.
Executive summary:

A bacterial mutagenicity study (Ames test) was conducted on LAS and was found to be negative for mutagenicity.

Endpoint:
in vitro gene mutation study in mammalian cells
Remarks:
Type of genotoxicity: gene mutation
Type of information:
read-across based on grouping of substances (category approach)
Adequacy of study:
key study
Study period:
May 16, 1995-June 30, 1995
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP laboratory study
Justification for type of information:
Category Approach; test material is reference substance LAS. LAS provides suitable read across for LAB Sulfonic Acids as both form the identical chemical species in aqueous solutions at neutral (physiological) pH, namely, the LAS ion (C10-13 linear alkyl benzene-SO3-) and would be expected to have similar genetic toxicity properties.
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 476 (In Vitro Mammalian Cell Gene Mutation Test)
GLP compliance:
yes (incl. certificate)
Type of assay:
mammalian cell gene mutation assay
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Metabolic activation system:
S9 from aroclor 1254 induced rat liver
Test concentrations with justification for top dose:
0, 0.6, 1, 1.8, 3, 6 ug/ml without S9
0, 6, 10, 18, 30, 60 ug/ml with S9
Vehicle / solvent:
None
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
yes
Remarks:
H0 medium
Positive controls:
yes
Positive control substance:
other: ethyl methane sulfonate; 3-(20-)methylcholanthrene
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium


DURATION
- Preincubation period: 1 week
- Exposure duration: 4 hrs
- Expression time (cells in growth medium): 6 days at 37 degree C for cloning efficiency study, 9 days for mutation assay


STAIN (for cytogenetic assays): Giemsa


NUMBER OF REPLICATIONS: 2


Evaluation criteria:
A test substance was considered mutagenic if a statistically significant dose-related increase in mutant frequency was found in concentrations with greater than 20% survival rate. The mean mutant frequency must also be significantly above the maximum spontaneous mutant frequency.
Statistics:
Statistical significance was determined by the t-test.
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
preliminary test showed cytotoxicity at >= 50 ug/ml without S9, and >= 100 ug/ml with S9.
Vehicle controls validity:
not examined
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
COMPARISON WITH HISTORICAL CONTROL DATA: In both the studies with and without S9, the mutant frequencies in the treated groups were statistically significantly higher than in the concurrent negative controls. However, the mutant frequencies in the treated groups were not significantly increased when compared to historical negative controls. There was also no dose-response relationship. The increased mutant frequency in treated groups was therefore not considered to be biologically significant.


Remarks on result:
other: all strains/cell types tested

Results of Test 1 ¿ Without S9 Mix            

Concentration (ug/ml)

Absolute cloning efficiency (%)

Mutant frequency ( x 106)

0

82

3 ± 2

0.6

86

7 ± 1

1

85

3 ± 2

1.8

78

5 ± 2

3

86

1 ± 1

6

83

0 ± 1

EMS

83

277 ± 17

Results of Test 1 ¿ With S9 Mix     

Concentration (ug/ml)

Absolute cloning efficiency (%)

Mutant frequency ( x 106)

0

90

2 ± 1

6

88

1 ± 1

10

84

9 ± 4

18

78

5 ± 3

30

89

3 ± 2

60

89

7 ± 2

MCA

81

91 ± 9

Results of Test 2 ¿ Without S9 Mix

Concentration (ug/ml)

Absolute cloning efficiency (%)

Mutant frequency ( x 106)

0

96

1 ± 1

0.6

92

2 ± 3

1

95

1 ± 1

1.8

93

5 ± 2

3

90

2 ± 1

6

91

6 ± 6

EMS

90

309 ± 20

Results of Test 2 ¿ With S9 Mix     

Concentration (ug/ml)

Absolute cloning efficiency (%)

Mutant frequency ( x 106)

0

90

2 ± 1

6

92

7 ± 3

10

88

9 ± 2

18

94

2 ± 1

30

93

2 ± 2

60

90

5 ± 1

MCA

95

89 ± 6

Conclusions:

The test substance is not mutagenic in either the presence or absence of metabolic activation.
Executive summary:

This study examined the potential of the test substance to cause mutations in mammalian cells. Chinese Hamster Ovary (CHO) cells were exposed to concentrations of 0, 0.6, 1, 1.8, 3, and 6 ug/ml without S9, and 0, 6, 10, 18, 30, and 60 ug/ml with S9. The cells were then examined for cytogenicity and mutation frequency. Ethyl methane sulfonate and 3-(20-)methylcholanthrene were used as positive control substances. The test substance was cytogenic at concentrations of 50 ug/ml or greater with metabolic activation, and 100 ug/ml or above without metabolic activation. There was no biologically significant increase in mutation frequency in the treated groups. The test substance is considered not mutagenic to CHO cells both in the presence and absence of S9.

Endpoint:
in vitro cytogenicity / chromosome aberration study in mammalian cells
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Study period:
May 25, 1995-November 23, 1995
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: GLP study done according to OECD guidelines. However, this study does not adequately address the results obtained at mildly cytotoxic concentrations.
Qualifier:
according to
Guideline:
OECD Guideline 473 (In Vitro Mammalian Chromosome Aberration Test)
GLP compliance:
yes (incl. certificate)
Type of assay:
in vitro mammalian chromosome aberration test
Species / strain / cell type:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Metabolic activation system:
S9 from Aroclor 1254 induced rat liver
Test concentrations with justification for top dose:
All concentrations in micrograms/ml

Test 1 with S9: 0.32, 0.63, 1.25, 2.5, 5, 10, 20, 39, 78
Test 1 without S9: 1.25, 2.5, 5, 10, 20, 39, 58,78, 156

Test 2 with S9: 2.5, 5, 10, 20, 26, 33, 39
Test 2 without S9: 20, 39, 58, 78, 130, 156

An additional test was done with S9 at the following dose levels:
2.5, 5, 7.5, 10, 15, 20, 25, and 30 ug/ml
Vehicle / solvent:
None
Untreated negative controls:
yes
Negative solvent / vehicle controls:
no
True negative controls:
no
Positive controls:
yes
Positive control substance:
other: methyl methanesulphonate, cyclophosphamide
Details on test system and experimental conditions:
METHOD OF APPLICATION: in medium


DURATION
- Exposure duration: 6 hrs with S9, 22 hrs without S9
- Expression time (cells in growth medium): 16-40 hrs with S9, 40 hrs without S9
- Selection time (if incubation with a selection agent): 2 hrs
- Fixation time (start of exposure up to fixation or harvest of cells): 24-48 hrs


SELECTION AGENT (mutation assays): Colcemid

NUMBER OF REPLICATIONS: 3


NUMBER OF CELLS EVALUATED: 100 metaphases


DETERMINATION OF CYTOTOXICITY
- Method: number of cells per culture


OTHER EXAMINATIONS:
- Determination of polyploidy: yes
- Determination of endoreplication: yes
Evaluation criteria:
A dosage was considered toxic if cell count was less then 60% of cell cultures. A test substance was considered clastogenic if a single dose caused the percentage of aberrant cells to be consistently greater than the 99% confidence limits of negative controls and there was also an increase at another dose level.
Statistics:
95% and 99% confidence limits
Species / strain:
Chinese hamster Ovary (CHO)
Metabolic activation:
with and without
Genotoxicity:
positive
Cytotoxicity / choice of top concentrations:
cytotoxicity
Remarks:
>= 15 microgram/ml with S9, >=58 microgram/ml without S9
Vehicle controls validity:
not examined
Untreated negative controls validity:
valid
Positive controls validity:
valid
Additional information on results:
In the absence of S9, only one culture (Test 2, 24 hr harvest, 20 ug/ml) showed a suspicious result. This single result was considered sporadic, as other cultures at this concentration, or at higher concentrations did not show a positive response. In Test 1, in the absence of S9, cytoxicity was seen at 78 micrograms/ml and above. In Test 2, in the absence of S9, cytoxicity was seen at concentrations of 58 micrograms/ml and above.

In Test 1, in the presence of S9, no positive results were seen at concentrations of up to 20 micrograms/ml. Metaphases could not be analyzed due to severe cytotoxicity at the 39 and 78 microgram/ml concentrations. In Test 2, in the presence of S9, one of the cultures at the 5 microgram/ml concentration gave a suspicious result, and both cultures at the 10 microgram/ml concentrations gave positive responses. Mild cytotoxity was also seen at the 10 microgram/ml concentration. At concentrations at and above 20 micrograms/ml, metaphases could not be analyzed due to severe cytotoxicity. No positive results were seen in the Test 2, 48 hr harvest cultures grown in the presence of S9, though moderate cytotoxicity was seen in one of the 20 microgram/ml cultures, and severe cytotoxicity was seen in all cultures above this concentration.

A third test was done in the presence of S9, which showed positive results at the 15 micrograms/ml concentration. However, this concentration was also moderately cytotoxic with only 26% of cells survival. However, due to the low survival of cells, these results are not definitive for determining clastogenicity. Higher concentrations were completely cytotoxic. An additional assessment was then performed at 10 micrograms/ml in the presence of S9, with negative results.

Remarks on result:
other: all strains/cell types tested

Abbreviations used in tables:

T ¿ Toxicity evident from morphological changes

TT- Toxicity evident from reduced cell count (<60% of vehicle)

TTT- Too toxic for metaphase assessment

Concentration (micrograms/ml)

Aberration Frequency (lesions/cell)

Aberrant Cell Frequency (% Including Gaps)

Aberrant Cell Frequency (% Excluding Gaps)

Cytotoxicity

Ham¿s F10 medium

0.01

1

0

Nil

Ham¿s F10 medium

0.02

1

1

Nil

0.32

-

-

-

Nil

0.32

-

-

-

Nil

0.63

-

-

-

Nil

0.63

-

-

-

Nil

1.25

-

-

-

Nil

1.25

-

-

-

Nil

2.5

0.01

1

0

Nil

2.5

0.00

0

0

Nil

5

0.00

0

0

Nil

5

0.05

5

0

Nil

10

0.01

1

0

Nil

10

0.01

1

0

Nil

20

0.00

0

0

Nil

20

0.00

0

0

Nil

39

-

-

-

TTT

39

-

-

-

TTT

78

-

-

-

TTT

78

-

-

-

TTT

Cyclophosphamide (20 micrograms/ml)

0.14

8

4

-

Cyclophosphamide

(30 micrograms/ml)

0.06

4

4

-

Cyclophosphamide

(40 micrograms/ml)

0.33

20

19

-

Test 1 ¿ Without S9 Mix, 24 hr Harvest

Concentration (micrograms/ml)

Aberration Frequency (lesions/cell)

Aberrant Cell Frequency (% Including Gaps)

Aberrant Cell Frequency (% Excluding Gaps)

Cytotoxicity

Ham¿s F10 medium

0.00

0

0

Nil

Ham¿s F10 medium

0.00

0

0

Nil

1.25

-

-

-

Nil

1.25

-

-

-

Nil

2.5

-

-

-

Nil

2.5

-

-

-

Nil

5

-

-

-

Nil

5

-

-

-

Nil

10

-

-

-

Nil

10

-

-

-

Nil

20

-

-

-

Nil

20

-

-

-

Nil

39

0.01

1

0

Nil

39

0.00

0

0

Nil

58

0.01

1

0

Nil

58

0.00

0

0

Nil

78

0.00

0

0

T

78

0.00

0

0

T

156

-

-

-

TTT

156

-

-

-

TTT

Methyl methane-sulphonate

(10 micrograms/ml)

0.03

3

1

-

Cyclophosphamide

(20 micrograms/ml)

0.16

14

10

-

Test 2 ¿ With S9 Mix, 24 hr Harvest

Concentration (micrograms/ml)

Aberration Frequency (lesions/cell)

Aberrant Cell Frequency (% Including Gaps)

Aberrant Cell Frequency (% Excluding Gaps)

Cytotoxicity

Ham¿s F-10 medium

0.01

1

0

Nil

Ham¿s F-10 medium

0.02

2

1

Nil

2.5

0.07

2

1

Nil

2.5

0.04

3

1

Nil

5

0.04

3

2

Nil

5

0.06

6

4

Nil

10

0.12

8

6

T

10

0.19

13

5

T

20

-

-

-

TTT

20

-

-

-

TTT

26

-

-

-

TTT

26

-

-

-

TTT

33

-

-

-

TTT

33

-

-

-

TTT

39

-

-

-

TTT

39

-

-

-

TTT

Cyclophosphamide

(40 micrograms/ml)

0.38

20

17

-

Cyclophosphamide

(50 micrograms/ml)

0.31

18

11

-

Test 2 ¿ With S9 Mix, 48 hr Harvest

Concentration (micrograms/ml)

Aberration Frequency (lesions/cell)

Aberrant Cell Frequency (% Including Gaps)

Aberrant Cell Frequency (% Excluding Gaps)

Cytotoxicity

Ham¿s F-10 medium

0.00

0

0

Nil

Ham¿s F-10 medium

0.00

0

0

Nil

2.5

0.01

1

0

Nil

2.5

0.01

1

1

Nil

5

0.00

0

0

Nil

5

0.02

2

2

Nil

10

0.03

2

1

Nil

10

0.02

2

1

TT

20

-

-

-

TTT

20

-

-

-

TTT

26

-

-

-

TTT

26

-

-

-

TTT

33

-

-

-

TTT

33

-

-

-

TTT

39

-

-

-

TTT

39

-

-

-

TTT

Cyclophosphamide

(40 micrograms/ml)

0.03

3

2

-

Cyclophosphamide

(50 micrograms/ml)

0.10

8

7

-

Test 2 ¿ Without S9 Mix, 24 hr Harvest

Concentration (micrograms/ml)

Aberration Frequency (lesions/cell)

Aberrant Cell Frequency (% Including Gaps)

Aberrant Cell Frequency (% Excluding Gaps)

Cytotoxicity

Ham¿s F-10 medium

0.02

2

2

Nil

Ham¿s F-10 medium

0.03

3

0

Nil

20

0.02

2

0

Nil

20

0.05

5

3

Nil

39

0.02

2

1

Nil

39

0.04

4

0

Nil

58

0.01

1

1

Nil

58

0.06

6

1

Nil

78

-

-

-

TTT

78

-

-

-

TTT

104

-

-

-

TTT

104

-

-

-

TTT

130

-

-

-

TTT

130

-

-

-

TTT

156

-

-

-

TTT

156

-

-

-

TTT

Methyl methane-sulphonate

(10 micrograms/ml)

0.30

21

14

-

Methyl methane-sulphonate

(20 micrograms/ml)

0.71

33

28

-

Test 2 ¿ Without S9 Mix, 48 hr Harvest

Concentration (micrograms/ml)

Aberration Frequency (lesions/cell)

Aberrant Cell Frequency (% Including Gaps)

Aberrant Cell Frequency (% Excluding Gaps)

Cytotoxicity

Ham¿s F-10 medium

0.01

1

1

Nil

Ham¿s F-10 medium

0.00

0

0

Nil

20

0.00

0

0

Nil

20

0.00

0

0

Nil

39

0.01

1

1

Nil

39

0.00

0

0

Nil

58

0.00

0

0

T

58

0.01

1

0

T

78

-

-

-

TTT

78

-

-

-

TTT

104

-

-

-

TTT

104

-

-

-

TTT

130

-

-

-

TTT

130

-

-

-

TTT

156

-

-

-

TTT

156

-

-

-

TTT

Methyl methane-sulphonate

(20 micrograms/ml)

0.21

11

8

-

Methyl methane- sulphonate

(40 micrograms/ml)

3.20

60

60

-

Test 3 ¿ With S9 Mix, 24 hr Harvest

Concentration (micrograms/ml)

Aberration Frequency (lesions/cell)

Aberrant Cell Frequency (% Including Gaps)

Aberrant Cell Frequency (% Excluding Gaps)

Cytoxicity

Ham¿s F-10 medium

0.04

4

0

Nil

Ham¿s F-10 medium

0.04

4

0

Nil

2.5

-

-

-

Nil

2.5

-

-

-

Nil

5

-

-

-

Nil

5

-

-

-

Nil

7.5

-

-

-

Nil

7.5

-

-

-

Nil

10

-

-

-

Nil

10

-

-

-

Nil

15

0.20

12

8

TT

15

0.18

12

6

TT

20

-

-

-

TTT

20

-

-

-

TTT

25

-

-

-

TTT

25

-

-

-

TTT

30

-

-

-

TTT

30

-

-

-

TTT

Cyclophosphamide

(30 micrograms/ml)

0.24

14

12

-

Cyclophosphamide

(40 micrograms/ml)

0.32

17

11

-

Test 3 - see tables below

Conclusions:
Interpretation of results (migrated information):
negative without metabolic activation
positive with metabolic activation at cytotoxic concentrations or above

The test substance is not clastogenic in the absence of metabolic activation. The test substance is also not clastogenic in the presence of metabolic activation at non-cytotoxic concentrations. At cytotoxic concentrations, the test substance is weakly clastogenic.
Executive summary:

This study examined the potential of the test substance Marlon A 350 to cause chromosomal aberrations in mammalian cells. Chinese hamster ovary cells were exposed to concentrations of 0.32 to 78 ug/ml with S9, and 1.25 to 156 ug/ml without S9. Methyl methanesuflphonate and cyclophosphamide were used as positive controls. No biologically significant results were seen in treated cultures in the absence of metabolic activation. Positive responses were seen at cytotoxic concentrations in the presence of S9. Concentrations below the level of cytotoxicty with S9 did not show positive results. The test substance is not clastogenic in the absence of metabolic activation, or with metabolic activation below cytotoxic concentrations. These results indicate that LAS is weakly clastogenic at cytotoxic concentrations but negative at concentrations below cytotoxic concentrations

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

Genetic toxicity in vivo

Description of key information

A series of in vivo mutagenicity studies are available. In the key study, 40 male and 40 female mice were given a single oral dose by gavage of 1122 mg/kg LAB Sulfonic Acid and evaluated for chromosome aberrations. Only a single dose has been evaluated which was in the range of the acute oral LD50 value for LAB Sulfonic Acid in rats (LD50 = 1470 mg/kg). Furthermore, slight cytotoxicity has been observed after 48 hours. No statistically significant or biologically relevant increases in the number of polychromatic erythrocytes with micronuclei were observed; therefore the test material is considered negative for cytogenicity.

In an in vivo mammalian chromosome aberration study on LAS (read across) by Osaka Prefectural Institute of Public Health Report 1976, groups of male mice were given doses of 200, 400, or 800 mg LAS/kg. This is about half the acute oral LD50 of 1655 mg/kg, as cited by the authors of the study. Mice were sacrificed at 6, 24, and 48 hrs, three of the mice from each dosage group were sacrificed, and bone marrow cells from the femurs collected and examined for chromosome aberrations. In addition, one group of mice was exposed daily for 5 consecutive days. Additional groups of mice were exposed to commercial detergents containing 19% or 17.1% of LAS. None of the treatment groups showed any significant increase in chromosome aberrations as compared to negative controls while the positive control, Mitomycin C, clearly showed an increase in chromosomal aberration frequency. Therefore, LAS was not considered clastogenic in this assay.

A second chromosomal aberration study on LAS (read across) was conducted by Masubuchi et al. 1976. In this study, groups of five male mice or five male rats were fed diets containing 0.9% LAS for 9 months (1125 mg/kg bw/d for mice, 405 mg/kg bw/d for rats). At the end of this period, the animals were sacrificed, and the bone marrow cells examined for chromosome aberrations. No increase in chromosome aberrations was seen as compared to negative controls in either species but no positive controls have been included in this assay. LAS was not clastogenic in this assay.

These same authors (Masubuchi et al. 1976) also conducted a dominant lethal study in mice. A group of seven male mice were fed a diet containing 0.6% LAS for 9 months (750 mg/kg bw/d). At the end of this period they were each mated with two untreated females. Females were sacrificed on day 13 of gestation for examination of ovaries and uteri. No evidence of dominant lethal mutations was observed as compared to the controls.

Negative results in the in vivo studies together with the negative results in the Ames test strongly indicate that LAS (read-across) and LAB Sulfonic Acids do not have mutagenic or clastogenic potential in vivo.

Link to relevant study records
Reference
Endpoint:
in vivo mammalian somatic cell study: cytogenicity / erythrocyte micronucleus
Remarks:
Type of genotoxicity: chromosome aberration
Type of information:
experimental study
Adequacy of study:
key study
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: GLP laboratory study
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 474 (Mammalian Erythrocyte Micronucleus Test)
GLP compliance:
yes (incl. certificate)
Type of assay:
micronucleus assay
Species:
mouse
Strain:
NMRI
Sex:
male/female
Details on test animals and environmental conditions:
Strain NMRI. Animals were approximately 22-26 g (male) and 20-25 g (female) and acclimated for 1 week to the test conditions (20 =/- 3 degrees C, 30-70% relative humidity, 12 hour light/dark cycle). Food was given daily and water was ad libitum. All animals were healthy at the time of test initiation.
Route of administration:
oral: gavage
Vehicle:
NaCl
Duration of treatment / exposure:
72 hours
Frequency of treatment:
single dose
Remarks:
Doses / Concentrations:
1122 mg/kg
Basis:
actual ingested
No. of animals per sex per dose:
40 males and 40 females per dose
Control animals:
yes
Positive control(s):
Endoxan (cyclophosphamid)
Tissues and cell types examined:
Cells were taken from the thigh.
Details of tissue and slide preparation:
Cells were mixed with cattle serum and suspended, then centrifuged. The sediment was then resuspended. The suspension was seperated in a cellulose chromatography column. This was centrifuged, and mixed with fetal calf serum and EDTA. This was air-dried for 24 hrs and stained with Giemsa.
Evaluation criteria:
number of polychromatid erythrocytes (PCE)
ratio of PCE to normochromatid erythrocytes (NCE)
number of cells with micronucleus
Sex:
male/female
Genotoxicity:
negative
Toxicity:
no effects
Vehicle controls validity:
valid
Negative controls validity:
valid
Positive controls validity:
valid

No significant increases in the number of polychromatic erythrocytes with micronuclei were observed.

Conclusions:
Interpretation of results (migrated information): negative
Executive summary:

No significant increases in the number of polychromatic erythrocytes with micronuclei were observed.

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

Additional information

Additional information from genetic toxicity in vivo:

In vivo genotoxicity data indicate that LAB Sulfonic Acids are not clastogenic. Additional data is available on LAS which provides suitable read across for LAB Sulfonic Acids as both form the identical chemical species in aqueous solutions at neutral (physiological) pH, namely, the LAS ion (C10-13 linear alkyl benzene-SO3-) and would be expected to have similar toxicological properties. LAS (read across) was consistently found not to cause induction of gene mutations in the Ames bacterial reverse mutation assay as well as in the OECD 476 in vitro mammalian cell gene mutation test. LAS (read across) was found to be weakly positive at cytotoxic concentrations, but negative at concentrations below cytotoxic concentrations, when tested in an in vitro chromosome aberration assay in CHO cells. When tested in a series of in vivo genotoxicity studies, LAS (read across) was consistently found to not cause any clastogenic or mutagenic responses. The positive result in the in vitro chromosome aberration study using a rodent cell line (CHO cells) derived from cancer tissues that is lacking proper cell cycle control has to be seen in the context of the extensive in vivo data. In vivo studies do assess genotoxicity under more realistic conditions, including exposure, and therefore the negative results in the in vivo studies together with the negative results in the Ames test strongly indicate that LAS (read-across) and LAB Sulfonic Acids do not have mutagenic or clastogenic potential in vivo.


Justification for selection of genetic toxicity endpoint
In vivo experimental studies, consistent with in vitro mutagenicity studies, considered more reliable than in vitro cytogenicity study.

Justification for classification or non-classification

Based on the negative results observed in the in vivo studies together with the negative results in the Ames test, LAB Sulfonic Acids are not expected to have mutagenic or clastogenic potential in vivo.