Sodium O-isobutyl dithiocarbonate

Genetic toxicity: in vitro

Administrative data

Endpoint:

in vitro gene mutation study in bacteria

Remarks:

Type of genotoxicity: gene mutation

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate. In addition, xanthates decompose on aging to form a number of byproducts, depending on the pH, temperature, etc. Risks associated with xanthate are, therefore, a function of the breakdown of the product or un-reacted raw materials remaining in the product.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1992

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 471 (Bacterial Reverse Mutation Assay)

Deviations:

yes

Remarks:

only 4 bacterial strains tested

Test guideline 2

Qualifier:

according to guideline

Guideline:

EPA OTS 798.5265 (The Salmonella typhimurium Bacterial Reverse Mutation Test)

Deviations:

no

GLP compliance:

not specified

Type of assay:

bacterial reverse mutation assay

Test material

Test material information

Constituent 1

Reference substance name:

Carbon disulphide

EC Number:

200-843-6

EC Name:

Carbon disulphide

Cas Number:

75-15-0

Molecular formula:

CS2

IUPAC Name:

dithioxomethane

Test material form:

aerosol dispenser: not specified

Remarks:

migrated information: aerosol

Details on test material:

Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.
In addition, xanthates decompose on aging to form a number of byproducts, depending on the pH, temperature, etc. Risks associated with xanthate are, therefore, a function of the breakdown of the product or un-reacted raw materials remaining in the product.
- Name of test material (as cited in study report): carbon disulphide
- Molecular formula (if other than submission substance): CS2
- Physical state: liquid
- Analytical purity: >99.8%
- Impurities (identity and concentrations): iron, <1 mg/kg; sulfide <3 mg/kg
- Purity test date: 03.07.1992
- batch No.: 0609206042530
- Storage condition of test material: kept cool in the original container
- Density: 1.264 g/cm2

Method

Species / strain

Species / strain / cell type:

S. typhimurium TA 1535, TA 1537, TA 98 and TA 100

Additional strain / cell type characteristics:

not specified

Metabolic activation:

with and without

Metabolic activation system:

S9 mix- rat liver, Aroclor 1254 administered

Test concentrations with justification for top dose:

0.005%, 0.01%, 0.025%, 0.05%, 0.1% v/v

Vehicle / solvent:

- Vehicle(s)/solvent(s) used: none

Controls

Untreated negative controls:

yes

Negative solvent / vehicle controls:

no

Remarks:

no solvent/vehicle used

Positive controls:

yes

Positive control substance:

other: in the abscence and presence of metabolic activation: 2-aminoanthracene (TA1535), benzo[alpha]pyrene (TA1537, TA100, TA98); in the abscence of metabolic activation: sodium azide (TA1535, TA100), 9-aminoacridine (TA1537), 2-nitrofluorene (TA98);

Remarks:

dicloromethane in a vapour phase (7.5% v/v) was included in each test without metabolic activation

Details on test system and experimental conditions:

METHOD OF APPLICATION: in agar (plate incorporation)

NUMBER OF REPLICATIONS:3/ treatment

DETERMINATION OF CYTOTOXICITY

- Method: abscence or thinning of the background lawn of non-revertant colonies

EXPOSURE TO CS2:
Sets of solidified plates were placed, with lids removed, in stainless steel racks, designed to keep the plates separate and permit atmospheric circulation, inside stainless steel vessels. These vessels were then sealed and partially evacuated. Calculated volumes of carbon disulphide liquid were injected into the vessels via a septum and allowed to vaporize, producing atmospheres containing carbon disulphide at the nominal concentrations
mentioned above.Sterile air was admitted to the vessels in order to equilibrate the contents to atmospheric pressure, and the vessels with their contents were incubated at 37°C for 48 hours. After removal from the vessels, the plates were incubated for a further day in order to permit revertant
colonies to grow to a size large enough to be scored.

Evaluation criteria:

number of revertants/plate

Results and discussion

Test results

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:

other: yes, only at the highest concentration

Vehicle controls validity:

not applicable

Untreated negative controls validity:

valid

Positive controls validity:

valid

Additional information on results:

Carbon disulphide was examined for its mutagenic activity in four histidine-dependent auxotrophs ofSalmonella typhimurium, strains TA98, TA100, TA1535, TA1537. Agar plates, seeded with the tester strains, were exposed to the test material in vapour phase, in the abscence and presence of metabolic activation, in the following nominal concentrations: 0.005%, 0.01%, 0.025%, 0.05% and 0.1% v/v (nominal). These concentrations were selected following preliminary toxicity tests in strain TA 98. Carbon disulphide did not exhibit any mutagenic activity under the conditions of this test. No increases in revertants were obtained in any of the four tester strains following exposure to carbon disulphide at the concentrations tested. Inhibition of bacterial growth, observed as thinning of the background lawn of non-revertant cells and reduction in revertant colony numbers, occurred in all strains with carbon disulphide at a nominal concentration of 0.1 % v/v. The positive and negative controls were valid.
The study was performed according to the OECD Guidelines for Testing of Chemicals No. 471 (1983) and US EPA (TSCA) Guideline § 798.5265 (1985, amended 1987).

Remarks on result:

other: all strains/cell types tested

Remarks:

Migrated from field 'Test system'.

Applicant's summary and conclusion

Conclusions:

Interpretation of results (migrated information):
negative

No mutagenic activity of CS2 detected.Carbon disulphide is both a reagent in the manufacture, as well as a decomposition product of xanthates. Sodium isobutyl xanthate readily decomposes to carbon disulphide, especially in the presence of moisture/water. Therefore, the health effects of carbon disulphide (CS2) need to be considered in the assessment of sodium isobutyl xanthate.
In addition, xanthates decompose on aging to form a number of byproducts, depending on the pH, temperature, etc. Risks associated with xanthate are, therefore, a function of the breakdown of the product or un-reacted raw materials remaining in the product.

Executive summary:

Carbon disulphide was examined for its mutagenic activity in four histidine-dependent auxotrophs of Salmonella typhimurium, strains TA98, TA100, TA1535, TA1537. Agar plates, seeded with the tester strains, were exposed to the test material in vapour phase, in the abscence and presence of metabolic activation, in the following nominal concentrations: 0.005%, 0.01%, 0.025%, 0.05% and 0.1% v/v (nominal). These concentrations were selected following preliminary toxicity tests in strain TA 98. Carbon disulphide did not exhibit any mutagenic activity under the conditions of this test. No increases in revertants were obtained in any of the four tester strains following exposure to carbon disulphide at the concentrations tested. Inhibition of bacterial growth, observed as thinning of the background lawn of non-revertant cells and reduction in revertant colony numbers, occurred in all strains with carbon disulphide at a nominal concentration of 0.1 % v/v. The positive and negative controls were valid. The study was performed according to the OECD Guidelines for Testing of Chemicals No. 471 (1983) and US EPA (TSCA) Guideline § 798.5265 (1985, amended 1987).