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Key value for chemical safety assessment

Genetic toxicity in vitro

Description of key information

No data are available on the reaction mass itself. However, several studies are available for the three components (Sodium chloride, sodium carbonate and sodium sulfate).

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:
weight of evidence
Study period:
1983
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: sufficient information is available for the interpretation of results.
Qualifier:
equivalent or similar to guideline
Guideline:
OECD Guideline 471 (Bacterial Reverse Mutation Assay)
Principles of method if other than guideline:
none
GLP compliance:
not specified
Type of assay:
bacterial reverse mutation assay
Target gene:
histedine locus
Species / strain / cell type:
other: Ames reversion test with his - S. typhimurium strains TA1535, TA1537, TA1538, TA98, TA100 and, in part, TA97, and in a DNA-repair test with trp- E. coli strains WP2 (repair-proficient), WP67 (uvrA polA ) and CM871 (uvrA- recAlexA -).
Details on mammalian cell type (if applicable):
not applicable
Additional strain / cell type characteristics:
not applicable
Metabolic activation:
with and without
Metabolic activation system:
The S9 mix, prepared according to Ames et al. (1975), contained 10% liver $9 fractions from Aroclor- treated Sprague-Dawley rats, whose protein concentration had been adjusted to 30 mg/ml.
Test concentrations with justification for top dose:
Each compound was tested with each strain, both with and without S9 mix, at various dilutions (in duplicate or triplicate plates) performed by a
geometric ratio of 2, starting from its solubility or toxicity limit.
Specific test concentrations not mentioned in the report.
Vehicle / solvent:
- Vehicle(s)/solvent(s) used: water
Untreated negative controls:
yes
Negative solvent / vehicle controls:
yes
True negative controls:
not specified
Positive controls:
other: not specified in the report but out of 135 chemicals tested few were the historical positive control.
Positive control substance:
other:
Details on test system and experimental conditions:
METHOD OF APPLICATION: plate incorporation and spot test

NUMBER OF REPLICATIONS: duplicate


Determination OF CYTOTOXICITY:
- Method
other: by back ground lawn

Evaluation criteria:
Criteria for positivity of results included rate of increase of induced versus spontaneous revertants, dose dependence and reproducibility in separate
experiments (De Serres and Shelby, 1979).
The indications concerning the effect of S9 mix on mutagenicity, are intended to specify the metabolic trends of positive compounds in the
presence of liver S9 fractions, as inferred from dose-response data obtained by varying the concentrations either of test compound or of S9
fraction.
In the Ames test the mutagenic potency was expressed by dividing the number of revertants in excess of controls - as determined at the top level
of the linear part of dose-response curves with the most sensitive strain (identified with a C) symbol + by the corresponding amount of compound (in nmoles). Potency data were in the absence of S9 mix for direct-acting mutagens and in the presence of S9 mix for mutagens requiring
metabolic activation or undergoing an increase in activity. For negative compounds, 'less than' figures were caluclated by dividing an arbitrary
value of 100 revertants by the nmoles corresponding to the maximum dose of compound tested.
Statistics:
The plate count means were presented.
Species / strain:
other: Salmonella typhimurium strains TA97, TA98, TA100. TA1535, TA 1537 and, TA1538
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: not specified in the report
Vehicle controls validity:
valid
Untreated negative controls validity:
valid
Positive controls validity:
not specified
Additional information on results:
TEST-SPECIFIC CONFOUNDING FACTORS
- Effects of pH: no data
- Effects of osmolality: no data
- Evaporation from medium: no data
- Water solubility: yes

RANGE-FINDING/SCREENING STUDIES: no data

COMPARISON WITH HISTORICAL CONTROL DATA: no data

ADDITIONAL INFORMATION ON CYTOTOXICITY: A 2-M concentration of NaCI reduces survival.

It is known also that 2 M NaCI enhances the mutation frequency, somatic recombination andgene conversion in diploid yeast (Magni and Sora, unpublished data; Parker et al., 1986). Therefore,NaCI may induce chromosome breakage as well asmutations in yeast.

none

Conclusions:
Results: negative with and without metabolic activation.

Based on the results of the experiment NaCl was negative in the Ames reverse mutation assay.
Executive summary:

All the compounds were assayed in the Ames test with 5 his- S. typhimurium strains (TA1535, TA1537, TA1538, TA98 and TA100), whose genetic features were described by Ames et al. (1975). Salmonella strains were a kind gift from Prof. Bruce N. Ames (Department of Biochemistry, University of California, Berkeley, CA, U.S.A.).

The plate-incorporation test was performed according to the standard procedure described by Ames et al. (1975), with some revisions suggested by Bruce N. Ames (personal communication) and now published by Maron and Ames (1983).

Each compound was tested with each strain, both with and without S9 mix, at various dilutions (in duplicate or triplicate plates) performed by a geometric ratio of 2, starting from its solubility or toxicity limit. Throughout the period of experiments the spontaneous reversion rate of Salmonella tester strains was within the ranges indicated by Ames et al. (1975) and Maron and Ames (1983).

All the compounds were assayed in the Ames test with 5 his- S. typhimurium strains (TA1535, TA1537, TA1538, TA98 and TA100), whose genetic features were described by Ames et al. (1975). Salmonella strains were a kind gift from Prof. Bruce N. Ames (Department of Biochemistry, University of California, Berkeley, CA, U.S.A.).

3 isogenic E. coli strains were used in the DNA-repair test, i.e. WP2 (wild-type, repair-profi164 cient) (Witkin, 1956), WP67 (uvrA-polA ) (Witkin, 1967) and CM871 (uvrA- recA lexA ) (Tweats et al., 1981). In some preliminary assays with the spot test strains WP2uvrA (uurA) (Hill,1958) and TM1080 (polA- lexA- plasmid R391) (Venturini and Monti-Bragadin, 1978) were also used. All these bacteria carry an ochre nonsense mutation blocking an intermediate process in the synthesis of tryptophan (Bridges et al., 1967). E. coli strains were a kind gift from Prof. C. Monti- Bragadin (Institute of Microbiology, University of Trieste, Italy).

The plate-incorporation test was performed according to the standard procedure described by Ames et al. (1975), with some revisions suggested by Bruce N. Ames (personal communication) and now published by Maron and Ames (1983).

Each compound was tested with each strain, both with and without S9 mix, at various dilutions (in duplicate or triplicate plates) performed by a geometric ratio of 2, starting from its solubility or toxicity limit. Throughout the period of experiments the spontaneous reversion rate of Salmonella tester strains was within the ranges indicated by Ames et al. (1975) and Maron and Ames (1983).

Criteria for positivity of results included rate of increase of induced versus spontaneous revertants, dose dependence and reproducibility in separate experiments (De Serres and Shelby, 1979).

The indications concerning the effect of S9 mix on mutagenicity, are intended to specify the metabolic trends of positive compounds in the

presence of liver S9 fractions, as inferred from dose-response data obtained by varying the concentrations either of test compound or of S9

fraction.

In the Ames test the mutagenic potency was expressed by dividing the number of revertants in excess of controls - as determined at the top level

of the linear part of dose-response curves with the most sensitive strain (identified with a C) symbol + by the corresponding amount of compound (in nmoles). Potency data were in the absence of S9 mix for direct-acting mutagens and in the presence of S9 mix for mutagens requiring

metabolic activation or undergoing an increase in activity. For negative compounds, 'less than' figures were caluclated by dividing an arbitrary value of 100 revertants by the nmoles corresponding to the maximum dose of compound tested.

Based on the results of the experiment NaCl was negative in the Ames reverse mutation assay.

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:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable, well-documented publication which meets basic scientific principles.
Principles of method if other than guideline:
Method: other: Ames; McCann and Yamasaki, 1975
GLP compliance:
no
Type of assay:
bacterial reverse mutation assay
Species / strain / cell type:
other: TA 92, 94, 98, 100, 1535, 1537
Metabolic activation:
with
Test concentrations with justification for top dose:
max. 10 mg/plate
Details on test system and experimental conditions:
- Ames test
- Species/cell type: S. typhimurium, TA 92, 94, 98, 100, 1535, 1537.
- Deficiences/Proficiences: his+
- Metabolic activation system: S9 mix, from livers of Fischer rats pretreated 5 days with polychlorinated biphenyls.
- Solvent: Phosphate buffer.
Metabolic activation:
with
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: not reported
Remarks on result:
other: other: TA 92, 94, 98, 100, 1535, 1537
GENOTOXIC EFFECTS: 
- With metabolic activation: Negative. 
- Without metabolic activation: Not performed.
PRECIPITATION CONCENTRATION: Not reported.
FREQUENCY OF EFFECTS: Not reported.
CYTOTOXIC CONCENTRATION:  
- With metabolic activation:10 mg/plate. 
- Without metabolic activation: Not performed.
TEST-SPECIFIC CONFOUNDING FACTORS: Not reported. 
STATISTICAL RESULTS: Not reported.
Conclusions:
Based on this test sodium carbonate does not induce mutation in bacteria (TA 92, 94, 98, 1535 and 1537) in presence of metabolic activation.
Executive summary:

In a Ames test study performed on S. Typhimurium strains (TA 92, 94, 98, 100, 1535, 1537) in two replicates with metabolic activation no mutation was induced under the test condition.

Endpoint:
in vitro gene mutation study in bacteria
Remarks:
Type of genotoxicity: gene mutation
Type of information:
experimental study
Adequacy of study:
weight of evidence
Study period:
1988
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Principles of method if other than guideline:
Method: other: Salmonella/Microsome test, Ames et al, Mutation Res. 31, 347-364 (1975)
GLP compliance:
yes
Type of assay:
bacterial reverse mutation assay
Species / strain / cell type:
other: S. Typhimurium TA1535, TA1537, TA100, TA98
Metabolic activation:
with and without
Test concentrations with justification for top dose:
312.5 to 5000 µg per plate with 4 dilutions
Details on test system and experimental conditions:
Ames test.
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
other: no cytotoxicity observed
Remarks on result:
other: other: S. Typhimurium TA1535, TA1537, TA100, TA98
Remarks:
Migrated from field 'Test system'.

RS-Freetext:
EFFECTS: 
- With metabolic activation: both tests, no effects
- Without metabolic activation: both tests, no effects
FREQUENCY OF EFFECTS: n.a.
PRECIPITATION CONCENTRATION: not described 
MITOTIC INDEX: not described
CYTOTOXIC CONCENTRATION: no toxicity observed up to 5000
mg/l
TEST-SPECIFIC CONFOUNDING FACTORS: not described
STATISTICAL RESULTS: n.a.

Conclusions:
Sodium sulfate is not mutagenic in an Ames test in S. Typhimurium with and without metabolic activation.
Executive summary:

 In an Ames tested performed in S. Typhimurium (TA 1535, 1537, 100 and 98) negative results were found with and without metabolic activation. Therefore sodium sulfate does not induce mutation in bacteria.

Endpoint:
in vitro gene mutation study in bacteria
Type of information:
read-across from supporting substance (structural analogue or surrogate)
Adequacy of study:
weight of evidence
Justification for type of information:
See Read-across justification attached.
Data are not available on the reaction mass itself. The data on the three components, Sodium carbonate, Sodium chloride and Sodium Sulfate are used. These three components do not induce mutation in bacteria. Therefore the reaction mass is considered to not induce mutation in bacteria.
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Reason / purpose for cross-reference:
read-across source
Key result
Species / strain:
S. typhimurium, other: several strains
Metabolic activation:
with and without
Genotoxicity:
negative
Cytotoxicity / choice of top concentrations:
not specified
Vehicle controls validity:
not applicable
Untreated negative controls validity:
not applicable
Positive controls validity:
not applicable
Conclusions:
Based on the data on the three components the reaction mass is considered to not induce mutation in bacteria. No classification is required.
Endpoint conclusion
Endpoint conclusion:
no adverse effect observed (negative)

Additional information

One study is available on each component regarding bacterial mutagenic test.

For the sodium carbonate, One OECD 471 study (Ishidate et al, 1984) is available on the sodium hydrogenocarbonate. The results are negative with metabolic activation (without activation not performed)

For Sodium chloride One OECD 471 study (De Flora et al, 1984) is available. The sodium chloride is not considered as genotoxic

For the sodium sulfate, also on Ames test is available (Bayer 1988). . The results are negative with and without metabolic activation.

Justification for classification or non-classification

Based on the available data, the three components of the reaction mass is not genotoxic. Therefore the reaction mass itself is not considered to be genotoxic.