Tantalum

Endpoint summary

Description of key information

The skin and eye irritation potential of tantalum metal was investigated in two in vivo studies conducted according to OECD 404 and OECD 405. No irritation was observed in both studies. Therefore, tantalum does not warrant classification for eye/skin irritation in accordance with Regulation 1272/2008 (CLP).

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

26 September 2000 to 29 September 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2500 (Acute Dermal Irritation)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Age at study initiation: at least 12 weeks
- Weight at study initiation: 2.5 - 2.6 kg
- Housing: individually in stainless steel cages with perforated floors
- Diet: standard laboratory rabbit diet ad libitum (Special Diet Services STANRAB (P) SQC pellet)
- Water: ad libitum (potable water for human consumption)
- Acclimation period: 12 days
- Source: Harlan UK Ltd., Bicester, Oxon, England

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 ± 2 °C
- Humidity (%): 30 - 70 %
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light (0600 - 1800)

IN-LIFE DATES: From 26 September 2000 to 29 September 2000

Type of coverage:

semiocclusive

Preparation of test site:

shaved

Vehicle:

unchanged (no vehicle)

Remarks:

test material moistened with distilled water

Controls:

not specified

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied: 0.5 g

Duration of treatment / exposure:

4 hours

Observation period:

3 days

Number of animals:

3

Details on study design:

TEST SITE
- 24 hours prior to application of the test material, hair was removed with electric clippers from the dorso-lumbar region of each rabbit exposing an area of skin approximately 100 mm x 100 mm.
Approximately 0.5 g test material was applied under a 2-ply 25 mm x 25 mm porous gauze pad, which had been moistened with 0.5 mL distilled water, to one intact skin site on each animal. Each treatment site was covered with "Elastoplast" elastic adhesive dressing for 4 hours. The animals were not restrained during the exposure period and were returned to their cages immediately after treatment.

REMOVAL OF TEST SUBSTANCE
- Washing: at the end of the exposure period, the semi-occlusive dressing and gauze pad were removed and the treatment site was washed with warm water (36 °C) to remove any residual test material. The treated area was blotted dry with absorbent paper.

CLINICAL SIGNS:
- All animals were observed daily for signs of ill health or toxicity

DERMAL RESPONSES:
- Examination of the treated skin was made on day 1 (approximately 60 minutes after removal of the dressings) and on days 2, 3 and 4 (equivalent to approximately 24, 48 and 72 hours after exposure).

SCORING SYSTEM: see field "Any other information on materials and methods incl. tables" for further information.

Irritation parameter:

erythema score

Basis:

mean

Remarks:

score of three animals

Time point:

24/48/72 h

Score:

0

Max. score:

0

Remarks on result:

other: no dermal irritation was observed

Irritation parameter:

edema score

Basis:

mean

Remarks:

score of three animals

Time point:

24/48/72 h

Score:

0

Max. score:

0

Remarks on result:

other: no dermal irritation was observed

Irritant / corrosive response data:

There were no signs of toxicity or ill health in any rabbit during the observation period and no dermal irritation was observed at any time during the test.

Table 1: Dermal Reactions

Means of scores at approx. 24, 48 and 72 hours
Animal No.	Erythema	Oedema
1369	0	0
1370	0	0
1371	0	0

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the test according to OECD 404, the test material did not elicit any reaction in any of the animals during the course of the study that meant that the test material required classification as a skin irritant. The study is considered to be reliable, relevant and adequate for risk assessment and classification and labelling purposes.

Executive summary:

The skin irritation potential of the test material was determined in accordance with the standardised guidelines OECD 404, EU Method B.4 and EPA OPPTS 870.2500. Three rabbits received a single four hour application of 0.5 g of the test material and were assessed for the following 3 days for any signs of skin irritation. No sign of dermal irritation was observed in any of the animals at any time during the course of the study.

Under the conditions of the study, the test material is considered to be non-irritating to the skin on an internal system for description of irritation responses. The test material does not require classification for skin irritation in line with Regulation 1272/2008.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

4 October 2000 to 13 October 2000

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Age at study initiation: at least 12 weeks
- Weight at study initiation: 2.4 - 2.8 kg
- Housing: individually in stainless steel cages with perforated floors
- Diet: standard laboratory rabbit diet ad libitum (Special Diet Services STANRAB (P) SQC pellet)
- Water: ad libitum (potable water for human consumption)
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 ± 2 °C
- Humidity (%): 30 - 70 %
- Photoperiod (hrs dark / hrs light): 12 hours dark / 12 hours light (0600 - 1800)

IN-LIFE DATES: From 4 October 2000 to 13 October 2000

Vehicle:

unchanged (no vehicle)

Controls:

yes, concurrent no treatment

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 100 mg

TREATMENT PROCEDURE
- The weight of the test material which when gently compacted occupied a volume of 0.1 mL exceeded 100 mg on all occasions. However, 100 mg only was placed in the lower everted lid of one eye of each animal. The eyelids were gently held together for one second before releasing. The contralateral eye remained untreated and served as a control.

Duration of treatment / exposure:

The treated eyes were not washed following test material installation.

Observation period (in vivo):

All animals were observed daily for signs of ill health or toxicity. Examinations of the eyes were made 1, 24, 48 and 72 hours after installation.

Number of animals or in vitro replicates:

3
One animal was treated in advance of the other two, to ensure that if a severe response was produced, no further animals would be exposed.

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): irrigation was not performed.

SCORING SYSTEM: The reactions were scored in accordance with the numerical system outline in field "Any other information on materials and methods incl. tables".

TOOL USED TO ASSESS SCORE: Observation of the eyes was aided by the use of a handheld light.

Irritation parameter:

cornea opacity score

Basis:

mean

Remarks:

score of three animals

Time point:

24/48/72 h

Score:

0

Remarks on result:

other: No corneal damage was observed

Irritation parameter:

iris score

Basis:

mean

Remarks:

score of three animals

Time point:

24/48/72 h

Score:

0

Remarks on result:

other: No iridial inflammation was observed

Irritation parameter:

conjunctivae score

Remarks:

redness

Basis:

mean

Remarks:

score of three animals

Time point:

24/48/72 h

Score:

0.1

Reversibility:

fully reversible within: 2 days

Remarks on result:

other: Redness was seen in the eye of one male rabbit after 24 hours

Irritation parameter:

chemosis score

Basis:

mean

Remarks:

score of three animals

Time point:

24/48/72 h

Score:

0

Remarks on result:

other: No chemosis was observed

Irritant / corrosive response data:

No corneal damage or iridial inflammation was observed. Transient, hyperaemia of the blood vessels of the conjunctivae was seen in all animals, resolving completely by either one or two days after instillation.

Table 1: Ocular Reactions

Means of scores at approx. 24, 48 and 72 hours after administration
Animal No.	Corneal opacity	Iridial lesions	Conjunctival
			Redness	Chemosis
1389	0	0	0	0
1456	0	0	0.3	0
1457	0	0	0	0

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Under the conditions of the test according to OECD 405, the test material elicited only transient, very slight conjunctival irritation in any of the animals during the course of the study, meaning that the test material does not require classification as an eye irritant. The study is considered to be reliable, relevant and adequate for risk assessment and classification and labelling purposes.

Executive summary:

The eye irritation potential of the test material was determined in accordance with the standardised guidelines OECD 405, EU Method B.5 and EPA OPPTS 870.2400. Approximately 0.1 mL of test material was applied into one eye each of three rabbits and the animals assessed for 3 days to determine the grade of ocular reaction.

No corneal damage or any iridial effects were seen. Conjunctival effects consisted of transient, very slight irritation in one animal approximately 24 hours after installation. All signs of irritation had completely resolved 1 to 2 days following test material installation.

Under the conditions of the study, the test material is considered to be practically non-irritating to the eyes based on an internal system for description of irritation responses. The test material does not require classification for eye irritation in line with Regulation No. 1272/2008.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin

The skin irritation potential of the test material was determined in accordance with the standardised guidelines OECD 404, EU Method B.4 and EPA OPPTS 870.2500. Three rabbits received a single four hour application of 0.5 g of the test material and were assessed for the following 3 days for any signs of skin irritation.

No sign of dermal irritation was observed in any of the animals at any time during the course of the study.

Conflicting information was available in the form of handbook data (Merck), which suggested that tantalum can act as a skin irritant. Since no information on materials and methods was available to support classification as a skin irritant, and in consideration of a lack of epidemiological information to substantiate classification, this information was disregarded.

Eye

The eye irritation potential of the test material was determined in accordance with the standardised guidelines OECD 405, EU Method B.5 and EPA OPPTS 870.2400. Approximately 0.1 mL of test material was applied into one eye each of three rabbits and the animals assessed for 3 days to determine the grade of ocular reaction.

No corneal damage or any iridial effects were seen. Conjunctival effects consisted of transient, very slight irritation in one animal approximately 24 hours after installation. All signs of irritation had completely resolved 1 to 2 days following test material installation.

Conflicting information was available in the form of handbook data (Kirk-Othmer, Merck), which suggested that tantalum can act as an eye irritant. Since no information on materials and methods was available to support classification as an eye irritant, and in consideration of a lack of epidemiological information to substantiate classification, the handbook information was disregarded.

Justification for selection of skin irritation / corrosion endpoint:
The study was performed in line with GLP and accepted standardised guidelines with a high standard of reporting. The study was assigned a reliability score of 1 in accordance with the criteria for assessing data quality as outlined in Klimisch (1997) and considered suitable for assessment as an accurate reflection of the test material.

Justification for selection of eye irritation endpoint:
The study was performed in line with GLP and accepted standardised guidelines with a high standard of reporting. The study was assigned a reliability score of 1 in accordance with the criteria for assessing data quality as outlined in Klimisch (1997) and considered suitable for assessment as an accurate reflection of the test material.

Justification for classification or non-classification

The skin and eye irritation potential of tantalum metal was investigated in two in vivo studies conducted according to OECD 404 and OECD 405. No irritation was observed in both studies. Therefore, tantalum does not warrant classification for eye/skin irritation in accordance with Regulation 1272/2008 (CLP).