Tellurium

Endpoint summary

Description of key information

Acute oral toxicity: LD50 > 5000 mg/kg bw, OECD Guideline 401, GLP compliant
Acute inhalation toxicity: LC50 > 2.42 mg/L, according to OECD Guideline 403, GLP compliant
Acute dermal toxicity: no data available

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-01-22 to 1991-02-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

yes (incl. certificate)

Test type:

standard acute method

Limit test:

yes

Species:

mouse

Strain:

Swiss

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan/CPB, Austerlitz, the Netherlands
- Age at study initiation: 5-6 weeks old
- Weight at study initiation:
- Fasting period before study: 4 hours before dosing
- Housing: five females per cage, macrolon, type II, males individually in macrolon casegs type I.
- Diet (e.g. ad libitum): standard laboratory mice diet ad libitum
- Water (e.g. ad libitum): Tap water ad libitum.
- Acclimation period: 7 - 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): between 52 - 62 %
- Air changes (per hr): ca 10 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours Iight/12 hours dark cycle

Route of administration:

oral: gavage

Vehicle:

maize oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 50 % w/v
MAXIMUM DOSE VOLUME APPLIED: 10 mL/ kg max. Dose volume

Doses:

Preliminary study: 250, 500, 1000, 2000 and 5000 mg/kg bw
Main study: 5000 mg/kg bw

No. of animals per sex per dose:

Preliminary study: 2 females/ dose
Main study: 5 animals/ sex/ dose

Control animals:

no

Details on study design:

A preliminary test to determine the approximate level of acute oral toxicity was carried out with five groups of 2 females each. The five dose levels were 250, 500, 1000, 2000 and 5000 mg/kg bw. The dilutions prepared in the preliminary test were 25, 50, 100, 200 and 500 mg tellurium per mL maize oil and the dosing- volume was 10 mL/kg body weight.

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations were made within 1 hour and within 4 hours after dosing, and subsequently at least once
daily throughout the observation period of 14 days; body weights were recorded on day 0, 3, 7 and 14.
- Necropsy of survivors performed: yes

Preliminary study:

In the preliminary experiment, no mortality occurred during the 7-day observation period nor did the animals show any signs of abnormal behavior or abnormal appearance that could be ascribed to treatment with the test substance. On the basis of these results, it was decided to perform the main study with a limit-dose of 500 mg/kg body weight.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occured during the 14-day observation period.

Clinical signs:

The animals did not show any signs of abnormal behavior or abnormal appearance that could be ascribed to treatment with the test substance.

Body weight:

All animals gained weight during the 14-day observation period.

Gross pathology:

Examination of the animals at autopsy did not reveal any treatment-related gross changes.

Interpretation of results:

not classified

Remarks:

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

Conclusions:

The LD50 for tellurium (powder) was determined to be above 5000mg/kg bw .

Executive summary:

This acute oral toxicity study was conducted according to OECD Guideline 401 (Acute Oral Toxicity). A preliminary test to determine the approximate level of acute oral toxicity was carried out at dose levels of 250, 500, 1000, 2000 and 5000 mg/kg bw with 2 females each. No mortality and no treatment related effects were observed.

In the main study Swiss mice were given a single oral dose of tellurium (powder) in maize oil at a dose of 5000, mg/kg bw (5 animals/sex/ group) and observed for 14 days.

No mortality occurred. The animals did not show any signs of abnormal behavior or abnormal appearance that could be ascribed to treatment with the test substance.

All animals gained weight during the 14-day observation period.

Examination of the animals at autopsy did not reveal any treatment-related gross alterations.

Since no mortality occurred during the 14-day observation period, the oral LD₅₀of tellurium is considered to exceed 5000 mg/kg bw in both male and female mice.

 

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1991-01-22 to 1991-02-12

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

yes (incl. certificate)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Harlan/CPB, Austerlitz, the Netherlands
- Age at study initiation: ca 5 weeks old
- Weight at study initiation:
- Fasting period before study: overneight
- Housing: five animals per cage (stainless steel cages, fitted with wire screen floor and front)
- Diet (e.g. ad libitum): standard laboratory rat diet ad libitum
- Water (e.g. ad libitum): Tap water ad libitum.
- Acclimation period: 7 - 14 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): between 54 -77.5 %
- Air changes (per hr): ca 10 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours Iight/12 hours dark cycle

Route of administration:

oral: gavage

Vehicle:

maize oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 50 % w/v
MAXIMUM DOSE VOLUME APPLIED: 10 mL/ kg max. Dose volume

Doses:

Preliminary study: 250, 500, 1000, 2000 and 5000 mg/kg bw
Main study: 5000 mg/kg bw

No. of animals per sex per dose:

Preliminary study: 2 females/ dose
Main study: 5 animals/ sex/ dose

Control animals:

no

Details on study design:

A preliminary test to determine the approximate level of acute oral toxicity was carried out with five groups of 2 females each. The five dose levels were 250, 500, 1000, 2000 and 5000 mg/kg bw. The dilutions prepared in the preliminary test were 25, 50, 100, 200 and 500 mg tellurium per mL maize oil and the dosing- volume was 10 mL/kg body weight.

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations were made within 1 hour and within 4 hours after dosing, and subsequently at least once daily throughout the observation period of 14 days; body weights were recorded on day 0, 3, 7 and 14.
- Necropsy of survivors performed: yes

Preliminary study:

In the preliminary experiment, no mortality occurred during the 7-day observation period nor did the animals show any signs of abnormal behavior or abnormal appearance that could be ascribed to treatment with the test substance. On the basis of these results, it was decided to perform the main study with a limit-dose of 500 mg/kg body weight.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occured during the 14-day observation period.

Clinical signs:

The animals did not show any signs of abnormal behavior or abnormal appearance that could be ascribed to treatment with the test substance.

Body weight:

All animals gained weight during the 14-day observation period.

Gross pathology:

Examination of the animals at autopsy did not reveal any treatment-related gross changes.

Interpretation of results:

not classified

Remarks:

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

Conclusions:

The LD50 for tellurium (powder) was determined to be above 5000mg/kg bw .

Executive summary:

This acute oral toxicity study was conducted according to OECD Guideline 401 (Acute Oral Toxicity). A preliminary test to determine the approximate level of acute oral toxicity was carried out at dose levels of 250, 500, 1000, 2000 and 5000 mg/kg bw with 2 females each. No mortality and no treatment related effects were observed.

In the main study Wistar rats were given a single oral dose of tellurium (powder) in maize oil at a dose of 5000, mg/kg bw (5 animals/sex/ group) and observed for 14 days.

No mortality occurred. The animals did not show any signs of abnormal behavior or abnormal appearance that could be ascribed to treatment with the test substance.

All animals gained weight during the 14-day observation period.

Examination of the animals at autopsy did not reveal any treatment-related gross alterations.

Since no mortality occurred during the 14-day observation period, the oral LD₅₀of tellurium is considered to exceed 5000 mg/kg bw in both male and female rats.

 

 

Reference 3

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

1996-01-31 to 1996-02-16

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to

Guideline:

OECD Guideline 401 (Acute Oral Toxicity)

GLP compliance:

yes (incl. certificate)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Wiga, Sulzfeld, Germany
- Age at study initiation: 5 - 6 weeks old upon arrival
- Weight at study initiation:
- Fasting period before study: overneight
- Housing: five animals per cage (stainless steel cages, fitted with wire screen floor and front)
- Diet (e.g. ad libitum): standard laboratory rat diet ad libitum
- Water (e.g. ad libitum): Tap water ad libitum.
- Acclimation period: 21 - 23 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3°C
- Humidity (%): between 32. 5 - 80 %
- Air changes (per hr): ca 10 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours Iight/12 hours dark cycle

Route of administration:

oral: gavage

Vehicle:

maize oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 50 % w/v
MAXIMUM DOSE VOLUME APPLIED: 10 mL/ kg max. Dose volume

Doses:

5000 mg/kg bw

No. of animals per sex per dose:

5 animals/ sex/ dose

Control animals:

no

Details on study design:

A screening was carried out with two females treated with a dose level of 5000 mg/kg body weight to check for mortality. Since no mortality was observed, the study was continued with three females and five males which were treated with the same dose level. All animals were dosed with a 500 mg/mL suspension in maize oil and a 10mL/kg body weight dosing volume.

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: observations were made within 1 hour and within 4 hours after dosing, and subsequently at least once daily throughout the observation period of 14 days; body weights were recorded on day 0, 3, 7 and 14.
- Necropsy of survivors performed: yes

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 5 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occured during the 14-day observation period.

Clinical signs:

No clinical symptoms were observed.

Body weight:

All animals gained weight during the 14-day observation period.

Gross pathology:

Examination of the animals at autopsy did not reveal any treatment-related gross alterations.

Interpretation of results:

not classified

Remarks:

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

Conclusions:

The LD50 for tellurium (powder) was determined to be above 5000mg/kg bw .

Executive summary:

This acute oral toxicity study was conducted according to OECD Guideline 401 (Acute Oral Toxicity). A screening was carried out with two female Wistar rats treated with a dose level of 5000 mg/kg bw to check for mortality. Since no mortality was observed, the study was continued with three females and five males which were treated with the same dose level and observed for 14 days.

No clinical symptoms were observed and no mortality occurred during the 14-day observation period. All animals gained weight during the 14-day observation period.

Examination of the animals at autopsy did not reveal any treatment-related gross alterations.

Since no mortality occurred during the 14-day observation period, the oral LD₅₀of tellurium is considered to exceed 5000 mg/kg bw in both male and female rats.

 

 

 

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

5 000 mg/kg bw

Quality of whole database:

The key studies are GLP-compliant and of high quality (Klimisch 1).

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

GLP compliance:

yes (incl. certificate)

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River Wiga, Sulzfeld, Germany
- Age at study initiation: 5-6 weeks old upon arrival
- Weight at study initiation: mean body weight 304g males, mean females 192 g
- Fasting period before study: no data
- Housing: five animals per cage stainless steel cages fitted with wire-mesh floor and front.
- Diet (e.g. ad libitum): standard laboratory rodent diet ad libitum
- Water (e.g. ad libitum): Tap water ad libitum.
- Acclimation period: no data

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18.5 - 21.5 °C
- Humidity (%): between 70-85 %
- Air changes (per hr): 10 air changes/hour
- Photoperiod (hrs dark / hrs light): 12 hours Iight/12 hours dark cycle

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: modified nose-only inhalation chamber from ADG Developments LTD.
- Exposure chamber volume: 60 L
- Method of holding animals in test chamber: plastic animal holders (Batelle).
- Source and rate of air: air from compressed air system; average flow 3.1 m³/h
- System of generating particulates/aerosols:
Due to the inhomogeneity of the particles sizes of the test material, the test material was ground during a short period of time using a grinder. In preliminary experiments it turned out that it was not possible to use any moving device for transportation of the particles to the aerosol generation device since the particles coalesced strongly during transport. Therefore, a means of transportation had to be found in which the particles did not move themselves. Hereto, a moving tray was developed with tow grooves filled with test material (effective length 58 cm). A test atmosphere was generated by moving the tray with one filled groove along the suction side of the airmover. (AIR VAC 100) which was operated with pressurized air. When reaching the end of the groove, the second groove was started. In the meantime the first groove was refilled. This procedure was repeated every 15 minutes. The generation system was placed in a hood.
The inhalation equipment was designed to expose tats to a continuous supply of fresh test atmosphere. The generated aerosol was passed to the inlet of the exposure unit. From there it was directed downward through the mixing chambers towards the animal holders. At the bottom of the unit the test atmosphere was exhausted.

- Method of particle size determination: 11 - stage cascade impactor
- Treatment of exhaust air: no data
- Temperature, humidity, pressure in air chamber: 20.3 +/- 0.1 °C; relative humidity was very low (12 +/- 1 %). Air has been used from the compressed air system has a very low relative humidity.

TEST ATMOSPHERE
- Brief description of analytical method used: Gravimetrical analysis; once each half hour by passing 10 L test atmosphere at 5 L/min through fiber glass filters.
- Samples taken from breathing zone: yes
- Particle size distribution: 72 % of the particles had an aerodynamic diameter between 1.8 and 4.2 µm.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

nominal concentration 6.7 g/m³
analytical concentration: 2.42 g/m³

No. of animals per sex per dose:

5 aminals per sex per dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The rats were visually inspected just before exposure, for reaction to treatment during the exposure, shortly after exposure, and once daily during the observation period. Body weights were recorded just prior to exposure and at days 7 and 14.
- Necropsy of survivors performed: yes

Statistics:

NA

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2.42 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: None of the rats died during or after exposure.

Mortality:

None of the rats died during or after exposure.

Clinical signs:

other: No abnormalities were seen during exposure except for black heads of all rats. Black heads, half closed eyes and hunched posture were observed immediately after exposure. Grey dust was seen on the fur of all rats the first two days of the observation peri

Body weight:

Almost all rats showed strongly decreased body weights one week after exposure compared with their pre-exposure weight; all rats had gained weight at the end of the 14-day observation period, although pre-exposure weights was just or nearly reached in female rats.

Gross pathology:

At autopsy, a garlic-like scent was smelled. Greyish, brownish spotted lungs were observed in all male rats. Female rats showed pale and/or grey-black stained lungs. In addition, a grey thymus was observed in 4 females.

The mean actual concentration and standard deviation turned out to be 2.42 (0.19) g/m³. Nominal concentration was 6.7 g/m³.

Particle size measurement showed that ca. 72 % of the particles had an aerodynamic diameter between 1.8 and 4.2 µm.

Interpretation of results:

Toxicity Category IV

Remarks:

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

Conclusions:

The 4-hour LC50 value for tellurium was higher than 2.42 g/m³.

Executive summary:

In an acute inhalation toxicity study according to OECD guideline 403, groups of young adult wistar rats (5/sex) were exposed by inhalation route to tellurium powder (99.5 % a.i.) for 4 hours to nose only at an analytical concentration of 2.42 g/m³ corresponding to 6.7 g/m³ nominal, which was the highest attainable concentration.  Animals then were observed for 14 days.

Since none of the rats died, it was concluded that the 4-hour LC50 value was higher than 2.42 g/m³  (mg/L)

No abnormalities were seen during exposure except for black heads. Black heads, half closed eyes and hunched posture were observed immediately after exposure. Grey dust on the fur was seen in all rats and baldness in female rats during the observation period.

Almost all rats showed strongly decreased body weights one week after exposure; weight gained was observed at the end of the 14-day observation period, although pre-exposure weights was just or nearly reached in female rats.

Greyish, brownish or black stained lungs were seen in all rats at autopsy. A grey thymus was observed in four out of five females.

Particle size measurement showed that ca. 72 % of the particles had an aerodynamic diameter between 1.8 and 4.2 µm.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

2 420 mg/m³

Quality of whole database:

The key study is GLP-compliant and of high quality (Klimisch 1).

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

No data are available for the dermal route, hower dermal is not considered to be the major route of exposure for tellurium. Furthermore, the physicochemical and toxicological properties do not suggest potential for significant rate of absorption through the skin.

No data gaps were identified. The available data are adequate for risk assessment and classification and labelling purposes.

Justification for selection of acute toxicity – oral endpoint
Data from three studies conducted according to OECD guideline 401 are available, two with rats and one with mice.
In all studies the LD50 was > 5000 mg/kg bw.

Justification for selection of acute toxicity – inhalation endpoint
In the acute inhalation toxicity study, according to OECD guideline 403 (Acute inhalation toxicity) the LC50 was > 2.42 g/m³ air.

Justification for classification or non-classification

According to the CLP Regulation (EU GHS Regulation (EC) No 1272/2008) no classification and labelling would be required for tellurium for acute oral, based on acute oral toxicity value of LD50 > 5000 mg/kg bw.

For the inhalation route classification in the acute toxicity category IV is required based on the LC50 value of > 2.42 mg/L air.