Sodium O-isobutyl dithiocarbonate

Biological effects monitoring

Administrative data

Endpoint:

biological effects monitoring

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)

Data source

Reference

Reference Type:

review article or handbook

Title:

Priority existing chemical Report No. 5

Author:

Dep. of Health and Ageing, Australian Government

Year:

1995

Bibliographic source:

National Industrial Chemicals Notification and Assessment Scheme

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Determination of carbon disulphide concentrations in blood or urine by Iodine-azide test and Estimation of urinary thio-thiazolidine-4-carboxylic acid (TTCA)

GLP compliance:

no

Type of study / information:

Biological monitoring for determination of carbon disulphide concentrations in blood or urine.

Test material

Test material information

Constituent 1

Reference substance name:

Sodium O-ethyl dithiocarbonate

EC Number:

205-440-9

EC Name:

Sodium O-ethyl dithiocarbonate

Cas Number:

140-90-9

IUPAC Name:

sodium O-ethyl dithiocarbonate

Constituent 2

Reference substance name:

sodium ethyl xanthate

IUPAC Name:

sodium ethyl xanthate

Test material form:

solid: compact

Results and discussion

Any other information on results incl. tables

Biological monitoring

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.

It is generally considered that adverse effects from exposure to xanthates (inhumans and animals) are associated with CS2 toxicity. It is not known whatcontribution to human toxicity is likely from inhalation/dermal absorption of CS2per se, as a xanthate decomposition product, and CS2 as a xanthate metabolite.

Determination of carbon disulphide concentrations in blood or urine is not useful as ameasure of exposure, as only 1% of the absorbed carbon disulphide is excretedunchanged in the urine.Estimation of the concentration of the metabolites of carbondisulphide can be used as a measure of exposure.

 

Iodine-azide test

The iodine-azide test is based on the capacity of a metabolite of carbon disulphideto catalyse the iodine-azide reaction. The time required for decolourisation ofiodine after addition of the iodine-azide reagent to the urine is an indication of theamount of carbon disulphide metabolite in the urine. The time is inversely andexponentially related to the concentration of the metabolite. The time is correctedaccording to the creatinine concentration to avoid collection of 24 hr urine samples.

An exposure coefficient can be calculated from the creatinine concentration.The iodine-azide reaction catalysed by the metabolite probably a thiazolidine is:

 

2NaN₃+ I₂→ 3N₂+ 2NaI

 

This method is sensitive to atmospheric concentrations of 16 ppm and above of carbondisulphide. Exposure is considered to be negligible if decolourisation does not occurwithin 3 hrs. This method is not a precise method of monitoring and only indicatesoverexposure.

 

This method has been modified by Jakubowski9 and is based on measurement of theamount of iodine used for titration of the carbon disulphide metabolites thatcatalyse the iodine-azide reaction. This method can be used to assess exposure tocarbon disulphide levels as low as 3 ppm.

 

Determination of thio compounds

Estimation of urinary thio-thiazolidine-4-carboxylic acid (TTCA) concentration by high performance liquid chromatography may be used to monitor carbon disulphideexposure. TTCA is formed in the body by the reaction between carbon disulphideand glutathione. Excretion of TTCA may reflect the rate of metabolism of carbon disulphide rather than exposure.

 

Applicant's summary and conclusion

Conclusions:

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.
It is generally considered that adverse effects from exposure to xanthates (in humans and animals) are associated with CS2 toxicity. It is not known what contribution to human toxicity is likely from inhalation/dermal absorption of CS2 per se, as a xanthate decomposition product, and CS2 as a xanthate metabolite.
Determination of carbon disulphide concentrations in blood or urine is not useful as a measure of exposure, as only 1% of the absorbed carbon disulphide is excreted unchanged in the urine. Estimation of the concentration of the metabolites of carbon disulphide can be used as a measure of exposure.