Potassium isopentyl dithiocarbonate

Endpoint summary

Description of key information

Skin irritation:
Corrosive (rabbits)

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

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

Adequacy of study:

weight of evidence

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

other: see 'Remark'

Remarks:

The study was not regarded reliable, since only summary from IUCLID 2000 data set is available and details on the test substance and study results are not available for assessment. However, the study was conducted according to OECD guideline 404. Read-across justification: Target substance belongs into the group of substances called xanthates. The xanthates are generally prepared from the reaction of the alkoxide, which reacts with carbon disulphide to give the xanthate. These substances contain common functional group which is dithiocarbonate (-OCSS-). Though they are structural analogues with the target substance. All these analogue substances are also used in similar use application as water solutions. All xanthates decompose in the presence of water. In neutral to alkaline media, they will release carbon disulphide, particular alcohol(s) and carbonates and dithiocarbonates. Carbon disulphide is the major and the most volatile and the most hazardous decomposition product of xanthates. It is also more toxic to human health than the target substance. As the xanthates can be considered as a group of substances which have structural similarity and similar behaviour in contact with water and in the physiological processes, their irritation as well as acute and systemic adverse effects to human health are similar. Therefore, and in order to avoid the unnecessary animal testing, the read-across data from the analogue xanthates is used to evaluate the irritation, and short term and/or long-term toxicological effects of the target substance. As the target substance is an unstable compound, the apparent toxicity reflects to the toxicity of the degradation products. The selection of the most critical degradation products for the hazard assessment are based on the known decomposition reaction of the target substance and based on the physicochemical properties and toxicological properties of the degradation products. The adverse effects through inhalation route are not relevant for the substance itself, which is a solid non-volatile pellet form substance. However, the most serious human health hazards are related to CS2 released from the target substance. Therefore, the formation of carbon disulphide by decomposition is the driving force for human health hazard assessment via inhalation and taken into account in DNEL derivation and in the exposure assessment of the target substance.

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

not specified

GLP compliance:

yes

Species:

rabbit

Strain:

not specified

Preparation of test site:

not specified

Vehicle:

physiological saline

Amount / concentration applied:

500 mg test substance + 0.15 ml 0.9% NaCl

Duration of treatment / exposure:

4 hours

Irritation parameter:

other:

Basis:

mean

Remarks on result:

other: corrosive

Interpretation of results:

Category 1A (corrosive)

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

Potassium isobutyl xanthate (500mg) was applied in the volume of 0.15ml on the flank of rabbit. The test substance was classified as corrosive.

Executive summary:

This study was performed for analogue substance. The study was regarded not reliable, since available document is insufficient for assessment. However, the study was conducted according to the OECD 404 guideline. This study is used as weight of evidence in the hazard assessment.

The classification of this substance is based on the pH, which is above > 11.5. Thus, classification for Skin Corr. 1A is warranted.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (corrosive)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation

Data waiving:

study scientifically not necessary / other information available

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation

The weight of evidence approach is used to assess the skin irritation of potassium isoamyl xanthate based on the classification of the substance and the animal data from the analogue substance, potassium isobutyl xanthate.

A skin irritation study by Clariant (1987) was performed for analogue category substance, potassium isobutyl xanthate. The read-across justification is presented in the Annex I of this CSR.

The test substance (500 mg) was applied in the volume of 0.15 ml on the flank of rabbits for 4 hours. The test substance was evaluated to be corrosive to the skin of the rabbit. The study was regarded not reliable, since available document is insufficient for assessment. However, the study was conducted according to the OECD 404 guideline.

As a conclusion, the classification of potassium isoamyl xanthate is based on the pH, which is above > 11.5 at maximum concentration of 25 % water solution in which the substance in used . Thus, classification for Skin Corr. 1A is warranted. Animal study conducted for the analogue substance supports this conclusion.

Eye irritation

No data available. Based on the high pH of potassium isoamyl xanthate solution the substance is classified as corrosive to skin (Skin Corr. 1A) and with the risk of eye damage. According to column 2 of REACH Annex VIII no testing for eye irritation is required.

Respiratory irritation

The decomposition products of potassium isoamyl xanthate, 3-methyl-1-butanol, has self-classification based on lead registration 2010 as STOT SE3 H335; affected organ: respiratory tract; route of exposure: inhalation. 1-pentanol, released only trace amounts, has harmonized classification as STOT SE H335. The concentrations of 3 -methyl-1 -butanol and 1-pentanol are not expected to exceed the generic concentration limit (GCL) of 20 % to trigger classification of the mixture, since the target substance is used typically only as 20 % solution and the target substance decomposes slowly in use applications. Alcohols also degrade rapidly in aqueous solutions. Thus, the classification for respiratory irritation is not needed for potassium isoamyl xanthate.

Justification for selection of skin irritation / corrosion endpoint:
The substance is classified as Skin. Corr. 1A with risk of eye damage based on the high pH of the water solutions of the substance. Thus, no study needed. However, there is available one study conducted for the analogue substance, potassium isobutyl xanthate, supporting this classification.

Justification for selection of eye irritation endpoint:
The substance is classified as Skin. Corr. 1A with risk of eye damage based on the high pH of the water solutions of the substance. Thus, no study needed.

Effects on skin irritation/corrosion: corrosive

Justification for classification or non-classification

Based on the pH of the substance and animal data from the analogue substance, potassium isoamyl xanthate has to be classified to hazard class Skin Corr. 1A with the risk of serious damage of eyes according to CLP Regulation 1272/2008 and as C; R35 according to Directive 67/548/EEC.