Dicopper sulphide

Acute Toxicity: dermal

Administrative data

Endpoint:

acute toxicity: dermal

Type of information:

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

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Already evaluated by the Competent Authority for Biocides and Existing Substances Regulations.

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

2002

Materials and methods

Test guideline

Test guideline 1

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Test guideline 2

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

yes

Test material

Test material information

Constituent 1

Reference substance name:

copper oxide

IUPAC Name:

copper oxide

Constituent 2

Reference substance name:

Copper oxide

EC Number:

215-269-1

EC Name:

Copper oxide

Cas Number:

1317-38-0

Molecular formula:

CuO

IUPAC Name:

copper(II) oxide

Details on test material:

Lot/Batch number: 02-0084
Description: Brown/black powder.
Purity: 97.7% cupric oxide.
Stability: Stable at room temperature.
Molecular formula: CuO
Molecular weight: 79.55
Smiles notation: O=[Cu]
InCHI: 1s/Cu.O

Test animals

Species:

rat

Strain:

Sprague-Dawley

Sex:

male/female

Details on test animals or test system and environmental conditions:

Source: Charles River (UK) Ltd, Margate, Kent, UK.
Age/weight at study initiation: At the start of the study the animals weighed at least 200g and were approximately 8 weeks old.

Administration / exposure

Type of coverage:

semiocclusive

Vehicle:

water

Remarks:

The test substance was moistened with distilled water.

Details on dermal exposure:

Area covered: 10% of body surface.
Removal of test substance: The test site was swabbed with arachis oil BP to remove any residual material.

Duration of exposure:

24 hours.

Doses:

2000 mg/kg b.w.
Concentration in vehicle: Not reported.
Total volume applied: Not reported.

No. of animals per sex per dose:

5 male and 5 female animals per group.

Control animals:

no

Details on study design:

Postexposure period: 14 days.
Examinations: Clinical observations, mortality, dermal reactions, irritation, bodyweights and necropsy.
Observations for death or toxicity were taken 0.5, 1, 2 and 4 hours after dosing and then once daily for fourteen days. Dermal reactions and signs of irritation were measured after removal of the dressings and once daily for fourteen days. Individual bodyweights were measured prior to dosing and seven and fourteen days after treatment. All animals were subjected to gross pathological examination after death.

Statistics:

Acute dermal median lethal dose (LD50) was determined from mortality data and not by statistical analysis.

Results and discussion

Effect levels

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

There were no mortalities among any of the treated animals at study termination.

Clinical signs:

other: There were no signs of systemic toxicity at any observation time point in any of the treated animals.

Gross pathology:

No abnormalities were noted at necropsy.

Other findings:

There were no signs of dermal irritation at any observation time point in any of the treated animals.

Any other information on results incl. tables

There were no mortalities or signs of systemic toxicity among any of the animals treated with copper oxide at the test concentration of 2000 mg/kg b.w.

The acute median lethal dose (LD₅₀) of copper oxide in the Sprague-Dawley CD (Crl: CD (SD) IGS BR) strain of rat was, therefore, found to be >2000 mg/kg b.w.

Justification of the read-across from copper (II) oxide to dicopper sulphide:

In order to minimise animal testing, data on the acute dermal toxicity, eye irritation and sensitisation potential of copper(II) oxide have been read across to dicopper sulphide (copper (II) oxide is unclassified on the basis of acute toxicity, irritation and sensitisation potential). These are both simple inorganic copper compounds with low water solubility and an anion of no toxicological concern. In fact, theoretical estimates for the solubility of dicopper sulphide are orders of magnitude lower than those of the oxide, ranging from 3.43E-10 µg/L to 1.36E-08 µg/L (see the attached document "The Solubility Products of Copper Sulphide" for further information). It is generally accepted that lower water solubility can be equated to lower bioavailability and hence acute toxicity; an effect clearly seen by a comparison of copper(II) oxide toxicity with that of the more soluble copper(I) oxide. On this basis, it is considered that a read-across of the acute toxicological, irritation and sensitisation properties from copper(II) oxide to dicopper sulphide represents a reasonable worst-case approach, and leads to that conclusion that dicopper sulphide is similarly unclassified. This conclusion is supported by the fact that acute oral toxicity (Bradshaw, 2012) and skin irritation testing (Warren, 2012) carried out with dicopper sulphide confirms that this compound is unclassified for these endpoints.

 

 

Applicant's summary and conclusion

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute median lethal dose (LD50) of copper oxide in the Sprague-Dawley CD (Crl: CD (SD) IGS BR) strain of rat was found to be >2000 mg/kg b.w.

Executive summary:

Materials and Methods:

The study was performed to assess the acute dermal toxicity of copper oxide in Sprague-Dawley CD (Crl:CD (SD) IGS BR) strain rats. A group of 10 animals (five male and five female) were given a single, 24-hour semi-occluded dermal application of test material moistened with distilled water at a dose level of 2000 mg/kg bw to an area of shorn skin (approximately 10% of the total body surface area).

The animals were observed for death or overt signs of toxicity 0.5, 1, 2 and 4 hours after dosing and subsequently once daily for 14 days. Following removal of the dressing (after 24-hours exposure), the test sites were examined for evidence of primary irritation and scored according to the scale from Draize J. H. 1977.

Individual bodyweights were recorded prior to application of the test material, on Day 0, 7 and 14.

At the end of the study, animals were sacrificed and subjected to gross necropsy. The appearance of any macroscopic abnormalities was recorded.

The study was conducted according to OECD Guidelines for the Testing of Chemicals No. 402 'Acute Dermal Toxicity' (adopted 24 February 1987) and Commission Directive 92/69/EEC Method B3 Acute Toxicity (Dermal).  The study was also conducted according to GLP.

No deviations from the test guidelines, or deficiencies in the method were reported.

Results and Discussion:

There were no mortalities, signs of systemic toxicity, or dermal irritation among any of the animals treated with copper oxide at the test concentration of 2000 mg/kg b.w. All animals showed expected gains in bodyweight over the study period and there were no abnormalities noted at necropsy.

The acute median lethal dose (LD50) of copper oxide in the Sprague-Dawley CD (Crl: CD (SD) IGS BR) strain of rat was, therefore, found to be >2000 mg/kg b.w.

The test material does not meet the criteria for classification and will not require labelling for dermal toxicity.