Sodium O-isobutyl dithiocarbonate

Field studies

Administrative data

Endpoint:

field studies

Type of information:

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

Adequacy of study:

supporting study

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

GLP compliance:

not specified

Type of measurement:

Atmospheric monitoring

Media:

air

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:

Carbonodithioic acid, O-ethyl ester, sodium salt.

IUPAC Name:

Carbonodithioic acid, O-ethyl ester, sodium salt.

Constituent 3

Reference substance name:

sodium ethyl xanthate

IUPAC Name:

sodium ethyl xanthate

Results and discussion

Any other information on results incl. tables

Atmospheric monitoring

Atmospheric monitoring for sodium ethyl xanthate is not carried out at the minesites where it is used. Random instantaneous sampling for carbon disulphide isundertaken at some mine sites and in holds of ships, however, very limitedmonitoring data were available for assessment. Monitoring for carbon dilsulphide atmost mine sites was carried out using detector tubes either Drager or Kitagawa“length of stain” tubes. Other collection devices used include activated charcoaltubes and portable gas chromatography.In some States the rail authorities have carried out random monitoring for carbon disulphide before unloading sodium ethyl xanthate.

 

Western Mining Corporation

Western Mining Corporation submitted data from a review undertaken by IndustrialRisk Management Pty Ltd 36 of more than 400 atmospheric samples reported to theDepartment of Mines. The samples measured carbon disulphide levels at theirvarious mining operations and the results showed that:

• the maximum carbon disulphide level measured was 15 ppm in the mixing

section;

• only two readings were above 10 ppm;
• only 20 readings were at or above 5 ppm and most of these were recorded as being

in the “mixing section”; and

• the average concentration of atmospheric carbon disulphide from 133 samples

taken in the mixing section was less than 2.5 ppm.

 

Western Mining also submitted atmospheric monitoring data from Olympic DamOperations as shown in Table1. No information was supplied on the number ofsamples. All samples were instantaneous readings.

 

 

Table1: Carbon disulphide levels (instantaneous) at Olympic Dam Operations, WesternMining Corporation Ltd

 

 

Location	Average CS2 (ppm)	Maximum CS2 (ppm)
Xanthate mixing area	5	15
Flotation area	2	7

 

 

Mt Isa Mines Limited

Atmospheric monitoring of carbon disulphide at Mt Isa Mines Ltd was undertakenusing Kitagawa “length-of-stain” detector tubes. The carbon disulphide levelsmeasured at the various sites in the mine are provided in Table2.

 

Table2: Carbon disulphide levels (instantaneous) at Mt Isa Mines Ltd

 

Area	Activity description	CS2 level (ppm)
Reagent Mixing Plant	Between storage shed and tanks with sodium ethyl xanthate drums opened for 1 hr in full sun	2
	Walkway over spillage pump	< 0.3
	Drum crushing area	< 0.3
	Walkway above stock tanks, downward of tanks	< 0.3
Flotation area	Area between cell banks, between two cell sodium ethyl xanthate addition points	1
	Raised aisle between xanthate distributors	5

 

 

Pasminco Mining, Broken Hill

Routine atmospheric monitoring for carbon disulphide is not performed by PasmincoMining at Broken Hill. However, carbon disulphide levels as high as 16 ppm havebeen detected a few metres from the mixing station using a Drager tube.

Government authorities

In some States the rail authorities carry out random monitoring for carbondisulphide at the time of arrival of sodium ethyl xanthate before transferring theload from the ship on to trains. Queensland authorities have reported carbondisulphide levels as high as 20 ppm in containers with the door slightly open, whensome of the drum lids were observed to be loose.

Summary

The exposure standard recommended by the National Commission for carbondisulphide is a TWA of 10 ppm. From the limited data submitted for assessment itappears that, generally, carbon disulphide levels at the mine sites are below theTWA. However, instantaneous sampling using detector tubes indicated that, attimes, short-term excursions above 10 ppm occurred in the mixing area during mixingactivity at some user sites. High levels were also recorded in containers in shipholds on arrival of sodium ethyl xanthate at the ports.

The monitoring data indicate that there is the potential for exposure to high levelsof carbondisulphide during mixing and transport. However, the data wereinadequate to demonstrate how widespread this problem is and whether there isthe potential for exposure in other areas or activities.

Applicant's summary and conclusion

Conclusions:

Western Mining Corporation submitted data from a review undertaken by Industrial Risk Management Pty Ltd 36 of more than 400 atmospheric samples reported to the Department of Mines. The samples measured carbon disulphide levels at their various mining operations and the results showed that:
• the maximum carbon disulphide level measured was 15 ppm in the mixing
section;
• only two readings were above 10 ppm;
• only 20 readings were at or above 5 ppm and most of these were recorded as being
in the “mixing section”; and
• the average concentration of atmospheric carbon disulphide from 133 samples
taken in the mixing section was less than 2.5 ppm.

Executive summary:

Sodium ethyl xanthate readily decomposes in the presence of moisture and heat toevolve carbon disulphide. Some mining sites have used other xanthates that aremore stable and resistant to heat and moisture. However, due to their structural similarity, it is expected that all xanthates would have similar health effects either due to the xanthate or carbon disulphide.

Atmospheric monitoring for sodium ethyl xanthate is not carried out at either thesites of manufacture or end-use.When water is added to Sodium ethyl xanthate itreacts with water to form the others substances: alcohol, sodium carbonate,trithiocarbonate and carbon disulphide.

 Monitoring is however carried out for CS2,which is considered to be the major hazard during manufacture, storage and useof xanthates.