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Toxicological information

Acute Toxicity: oral

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Administrative data

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:
other: Guideline study, all study parameters are well documented and based on the specific guideline.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
1991
Report Date:
1991

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 401 (Acute Oral Toxicity)
GLP compliance:
yes (incl. certificate)
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
solid: particulate/powder
Remarks:
migrated information: powder
Details on test material:
- Name of test material (as cited in study report): Tellurium
- Substance type: inorganic
- Physical state: fine black powder
- Analytical purity: > 99.5 %
- Lot/batch No.: 1103
- Storage condition of test material: first at 4 °C in the dark, later at ca. 20 °C

Test animals

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

Administration / exposure

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

Results and discussion

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.
Effect levels
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.

Applicant's summary and conclusion

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.