Tellurium

Endpoint summary

Description of key information

No irritation/corrosion to skin or eye was observed in the conducted studies with Tellurium. Furthermore no irritation was reported in an acute inhalation study with tellurium powder. 

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-06-13 to 2012-06-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 439 (In Vitro Skin Irritation: Reconstructed Human Epidermis Test Method)

Qualifier:

according to guideline

Guideline:

EU Method B.46 (In Vitro Skin Irritation: Reconstructed Human Epidermis Model Test)

GLP compliance:

yes (incl. QA statement)

Details on test animals or test system and environmental conditions:

Human Skin model:
EPISKIN-SM is a three-dimensional human epidermis model. Adult human-derived epidermal keratinocytes are seeded on a dermal substitute
consisting of a collagen type I matrix coated with type IV collagen. A highly differentiated and stratified epidermis model is obtained after 13-day
culture period comprising the main basal, supra basal, spinous and granular layers and a functional stratum corneum (Tinois et al., 1994). Its use
for skin irritation testing involves topical application of test materials to the surface of the epidermis, and the subsequent assessment of their
effects on cell viability.

Details on study design:

The irritation potential of a chemical may be predicted by measurement of its cytotoxic effect, as reflected in the MTT assay, on the EPISKIN reconstituted human epidermis. This method is approved by international regulatory agencies as a replacement for the identification of irritants / corrosives in the in vivo Rabbit skin assay (OECD 404).

Irritation / corrosion parameter:

other: other: relative viability (%)

Value:

103

Remarks on result:

other:

Remarks:

Basis: mean. Time point: after 15 minutes incubation. Reversibility: no data. Remarks: The relative cell viability was 103 % of negative control; as this value is clearly above the threshold value of ≤ 50 % for classification, thus the test substance is considered to be not irritating.. (migrated information)

Substance	Optical Density (OD)		Viability (%)
Negative Control: PBS	1	0.669	88
	2	0.748	98
	3	0.874	114
	mean	0.764	100
	standard deviation (SD)		13.11
Positive Control: SDS 5%	1	0.112	15
	2	0.058	7.6
	3	0.066	8.6
	mean	0.079	10
	standard deviation (SD)		4.01
Test Item: Tellurium	1	0.859	112
	2	0.779	102
	3	0.718	94
	mean	0.785	103
	standard deviation (SD)		9.02

 

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: other: CLP; EU GHS (Regulation (EC) No 1272/2008)

Conclusions:

Tellurium was considered to be not irritating in an in-vitro skin irritation study using the EPISKIN model.

Executive summary:

In a study conducted according to OECD guideline 439 in-vitro skin irritation of Tellurium was tested using the EPISKIN model.

Disks of EPISKIN (three units / chemical) were treated with Tellurium and incubated for 15 minutes at room temperature. Exposure of test material was terminated by rinsing with PBS. Epidermis units were then incubated at 37°C for 42 hours in an incubator with 5% CO2. The viability of the epidermis on each disk was assessed by incubating the tissues for 3 hours with MTT solution at 37°C in 5% CO2 protected from light. The formazan extract in acidified isopropanol was then spectrophotometrically evaluated for optical density (OD) and quantified.

SDS 5% and PBS treated epidermis were used as positive and negative controls, respectively. For each treated tissue viability was expressed as a % relative to negative control. If the mean relative viability after 15 minutes exposure and 42 hours post incubation is less or equal (≤) to 50% of the negative control, the test substance is considered to be irritant to skin.

Following exposure with Tellurium, the mean relative viability of epidermis was 103 %. All validity criteria were within acceptable limits and therefore the study can be considered as valid.

In conclusion results indicate that Tellurium can be considered to be non-irritating.

The reconstructed human epidermis model EPISKIN-SM is designed to predict and classify the skin irritant potential of chemicals, by measuring its cytotoxic effect, as reflected in the MTT assay, on the EPISKIN reconstituted human epidermis. This method is approved by international regulatory agencies as a replacement for the identification of irritants / corrosives in the in vivo Rabbit skin assay (OECD 404).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vitro / ex vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2012-05-15

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 438 (Isolated Chicken Eye Test Method for Identifying Ocular Corrosives and Severe Irritants)

Qualifier:

according to guideline

Guideline:

EU method B.48 (Isolated chicken eye test method for identifying occular corrosives and severe irritants)

GLP compliance:

yes (incl. QA statement)

Details on test animals or tissues and environmental conditions:

Species of chicken: ROSS 308
Source: TARAVIS KFT. 9600 Sárvár, Rábasömjéni út. 129.

Chicken heads were collected after slaughter in a commercial abattoir from chickens which are used for human consumption. Heads were collected
by a slaughter house technician. After collection, the heads were inspected for appropriate quality and wrapped with paper moistened with saline,
then placed in a plastic box that can be closed (4-5 heads/box).
The heads were transported to CiToxLAB Hungary Ltd. at ambient temperature at the earliest convenience.
The heads were received at CiToxLAB Hungary Ltd. and processed within approximately 2 hours of collection.

Vehicle:

unchanged (no vehicle)

Details on study design:

Assessment of the general IN VITRO eye irritancy and regulatory GHS classification.

Not irritating
3×I
2×I, 1×II
2xII, 1xI

Slightly irritating
(GHS category 2B: Mild irritant / causes eye irritation)
3×II
2×II, 1×III
1×I, 1×II, 1×III

Moderately irritating
(GHS category 2A: Irritant / causes eye irritation)
3×III
2×III, 1×II
2xI, 1xIV1
2×III, 1×IV
2×III, 1×I
2×II, 1×IV
1×II, 1×III, 1×IV

Corrosive/severely irritating
(GHS category 1: Irreversible effects on the eye / serious damage to the eye)

3×IV
2×IV, 1×III
2×IV, 1×II
2×IV, 1×I
Corneal opacity ≥ 3 at 30 min (in at least 2 eyes)
Corneal opacity = 4 at any time point (in at least 2 eyes)
Severe loosening of epithelium (in at least 1 eye)

Irritation parameter:

other: maximum corneal swelling

Run / experiment:

up to 75 min

Value:

0

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: ICE class I

Irritation parameter:

other: maximum corneal swelling

Run / experiment:

up to 240 min

Value:

0

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: ICE class I

Irritation parameter:

cornea opacity score

Run / experiment:

maximum

Value:

0

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: ICE class I

Irritation parameter:

fluorescein retention score

Run / experiment:

30 min.

Value:

0

Negative controls validity:

valid

Positive controls validity:

valid

Remarks on result:

other: ICE class I

	Corneal thickness (instrument units) Relative observation time (min)
Eye No.	-45 min	0	Change	30	75	Max change < 75	120	180	240	Max change < 240
1	86	86	0 %	86	86	0 %	86	86	86	0 %
3	88	87	-1 %	88	87	1 %	87	87	87	1 %
4	86	86	0 %	86	86	0 %	86	86	86	0 %
NC	86	86	0 %	86	86	0 %	86	86	86	0 %

 

 

	Corneal opacity score Relative observation time (min)
Eye No.	0	30	75	120	180	240	Max ∆ Opac
1	0	0	0	0	0	0	0
3	0	0	0	0	0	0	0
4	0	0	0	0	0	0	0
NC	0	0	0	0	0	0	0

 

	Fluorescein Relative observation time (min)
Eye No.	0	30
1	0	0
3	0	0
4	0	0
NC	0.5	0.5

 NC = negative control

 

POSITIVE CONTROL

Observation	Value		ICE Class*
Mean maximum corneal swelling at up to 75 min	3 %		I
Mean maximum corneal swelling at up to 240 min	7 %		II
Mean maximum corneal opacity	3.83		IV
Mean fluorescein retention	2.67		IV
Other Observations		The Imidazole was stuck on the cornea surface after the post-treatment rinse. The cornea surface was not cleared 240 minutes after the post-treatment rinse.
Overall ICE Class*		1xII 2xIV

 The positive control Imidazole was classed as severely irritating, GHS Classification: Category 1.

Interpretation of results:

not irritating

Remarks:

Migrated information Criteria used for interpretation of results: expert judgment

Conclusions:

In this in vitro eye irritation study in the Isolated Chicken Eyes model with Tellurium powder, the results suggest that the test item is not a severe eye irritant. Tellurium powder remained adhered to the cornea surface after the post-treatment rinse.

Executive summary:

An in vitro eye irritation study of the test item Tellurium was performed in isolated chicken’s eyes. The irritation effects of the test item were evaluated according to the OECD No.: 438 (07th September 2009).

After the zero reference measurements, the eye was held in horizontal position and 30 mg of Tellurium was applied onto the centre of the cornea such that the entire surface of the cornea was covered. After 10 seconds, the surface was rinsed with saline. The positive control eyes were treated with 30 mg Imidazole. The negative control eye was treated with 30 μL of isotonic saline.

In this in vitro eye irritation study in the Isolated Chicken Eyes model with Tellurium, the results suggest that the test item is not a severe eye irritant, all scores were zero. Tellurium remained adhered to the cornea surface after the post-treatment rinse.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Additional information

Skin irritation:

In a study conducted according to OECD guideline 439 in-vitro skin irritation of Tellurium was tested using the EPISKIN model.

Following exposure with Tellurium, the mean relative viability of epidermis was 103 %. All validity criteria were within acceptable limits and therefore the study can be considered as valid.

In conclusion results indicate that Tellurium can be considered to be non-irritating.

Eye irritation:

An in vitro eye irritation study of the test item Tellurium was performed in isolated chicken’s eyes (OECD guideline 438). The irritation effects of the test item were evaluated according to the OECD No.: 438 (07th September 2009).

In this in vitro eye irritation study in the Isolated Chicken Eyes model with Tellurium, the results suggest that the test item is not a severe eye irritant, all scores were zero. Tellurium remained adhered to the cornea surface after the post-treatment rinse.

Justification for selection of skin irritation / corrosion endpoint:
In an in vitro skin irritation study according to OECD 439 (Human Skin Model Test) Tellurium was found to be not irritating to the human skin.

Justification for selection of eye irritation endpoint:
In an in vitro "Isolated Chicken Eye Test Method for Identifying Ocular Corrosives and Severe Irritants" according to OECD 438, Tellurium was proven to be non-corrosive and/or not severe irritanting.

Justification for classification or non-classification

Skin irritation:

According to the CLP Regulation (EU GHS Regulation (EC) No 1272/2008) no classification and labelling is required for skin irritation of tellurium, based on reliable data from an in-vitro study according to OECD 439 (Human Skin Model Test). The mean relative viability of epidermis is well below the threshold for irritancy of ≤ 50%, for Tellurium, the mean relative viability of epidermis was 103 %.

The method is approved by international regulatory agencies as a replacement for the identification of irritants / corrosives in the in vivo Rabbit skin assay (OECD 404).

Eye irritation:

In an in vitro study conducted according to OECD Guideline no. 438, (2009), the observed scores for Tellurium in the study were all zero for maximum corneal swelling (up to 75 and 240 min), corneal opacity and fluorescein retention.

This corresponds to ICE class I for all parameters.

The absence of severe eye irritation is proven in the study and no classification and labelling for severe eye irritation according to CLP Regulation (EU GHS Regulation (EC) No 1272/2008) is required.

The ICE test method was re-evaluation by international regulatory agencies and the OECD guideline 438 was adopted (26 July 2013), mainly with respect to applicability domain for classification.

Now the use of the ICE test method is also recommended to identify chemicals that do not require classification for eye irritation or serious eye damage as defined by the UN GHS (No Category, NC).

The ICE test method is therefore suitable to be used as an initial step within a Bottom-Up testing strategy approach and negative results can be used for classification purposes.

In conclusion no classification and labelling for eye irritation according to CLP Regulation (EU GHS Regulation (EC) No 1272/2008) is required.