Cadmium telluride

Endpoint summary

Description of key information

Assessment of the acute oral toxicity of cadmium telluride in Nagy, Labresearch Ltd et al., 2008:
A limit study with Wistar CRL:(WI) BR rats was carried out according to OECD guideline no 423 to assess the oral LD50. No deaths and no abnormalities in clinical signs, body weights, and necropsy findings were observed for any of the animals. An LD50 value >2000mg/kg bw was reported.
Assessment of the acute inhalation toxicity of cadmium telluride in Nagy, Labresearch Ltd et al., 2008:
A study was carried out according to OECD guideline no 403 to assess the acute inhalation toxicity of CdTe when administered to rats for a single continuous 4 -hour period, followed by an observation period of 14 days.
The acute inhalation median lethal concentrations (4hr LC50) (and 95% confidence limits) of CdTe, in Wistar Crl:(WI) BR strain rats, were calculated to be: All animals: 2.71 mg/L; Male only: 2.53 mg/L; Female only: 2.87 mg/L

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

not applicable

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)

GLP compliance:

yes (incl. QA statement)

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (Europe)Laboratories Inc. (TOXI-COOP KFT, 1103 Budapest, Hungary)
- Weight at study initiation (g): 210-212
- Housing: in groups of 3 in solid-floor cages (Type III) with stainless steel mesh lids and softwood flake bedding.
- Diet: ssniff SM R/M-Z+H “Autoclavable Complete Feed for Rats and Mice – Breeding and Maintenance” (ssniff Spezialdiäten GmbH, D-59494 Soest,
Germany)
- Water: tap water from municipal supplies, as for human consumption, ad libitum.
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30-70 %
- Air changes (per hr): 8-12
- Photoperiod (hrs dark / hrs light): 12 hours of continuous artificial light in each twenty-four hour period.

Route of administration:

oral: gavage

Vehicle:

other: 1% carboxymethylcellulose

Details on oral exposure:

On the day prior to treatment, food was withheld from the animals overnight; water was available to them during this period. On the day of treatment, animals were weighed before dosing. The exact volume to be given was calculated base on each animal‟s body weight and a constant dose volume of 10 ml/kg. The test item formulation was stirred continuously throughout the dosing procedure to ensure each animal was treated with a homogenous solution. A single administration by oral gavage was given to a group of three female rats. Food was made available to the animals 3 hours after the treatment. The treatment was followed by a fourteen-day observation period.

Doses:

2000mg/kg

No. of animals per sex per dose:

6

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
Morbidity/Mortality: Animals were checked daily during the observation period for morbidity and/or mortality.
Clinical Signs: All animals were observed for clinical signs once during the first 30 minutes after treatment, approximately one, two, three, four and six hours after dosing and subsequently once daily for fourteen days. Individual observations were performed on the skin and fur, eyes and mucous membranes and also respiratory, circulatory, autonomic and central nervous system, somatomotor activity and behaviour pattern. Particular attention was directed to observation of tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma.
Bodyweight: Individual bodyweights were recorded prior to treatment on the day of dosing (Day 0) and on Days 7 and 14.
Necropsy: At the end of the fourteen-day observation period the animals were sacrificed by exsanguination under anaesthesia and gross necropsies performed. After examination of the external appearance, the cranial, thoracic and abdominal cavities were opened and the appearance of the tissues and organs was observed. All gross pathological changes were recorded for each animal on the post mortem record sheets.

Statistics:

Data evaluations included the relationship, if any, between the animals‟ treatment with the Test Item and the incidence and severity of all abnormalitiesincluding mortality, behavioural or clinical observations, bodyweight changes, macroscopic abnormalities or any other toxicological effects

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Mortality:

No mortality observed

Clinical signs:

other: No clinical signs observed

Gross pathology:

Necroscopy:
Occasional occurrences of pale, raised areas were observed in the lungs of two animals at necropsy. Several instances of pin-prick sized haemorrhage in the lungs were also noted but such alterations are frequently recorded at this facility and are considered to be caused by the termination method used. Mild hydrometra was noted in one female, this is a sporadic occurrence in laboratory maintained rat and is without toxicological significance.

Other findings:

none

none

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Tests done according to standard protocol. Good quality and considered useful for setting the reference value for acute oral toxicity (LD50>2000mg/kg)

Executive summary:

The purpose of this study was to assess the acute oral toxicity of CdTe.

No deaths occurred in two groups of three rats treated at a dose level of 2000 mg/kg. The acute oral lethal dose (LD50) of CdTe, in Wistar Crl:(WI) BR strain rats, was therefore considered to be greater than 2000 mg/kg.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LD50

Value:

2 000 mg/kg bw

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

Study period:

not applicable

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Reason / purpose for cross-reference:

reference to other study

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (Europe)Laboratories Inc. (TOXI-COOP KFT, 1103 Budapest, Hungary)
- Weight at study initiation (g): 224-299
- Housing: in groups of 5, by sex, in solid-floor cages (Type III) with stainless steel mesh lids and softwood flake bedding.
- Diet: ssniff SM R/M-Z+H “Autoclavable Complete Feed for Rats and Mice – Breeding and Maintenance” (ssniff Spezialdiäten GmbH, D-59494 Soest,
Germany)
- Water: tap water, as for human consumption, ad libitum.
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30-70 %
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12 hours of continuous artificial light in each twenty-four hour period.

Route of administration:

inhalation

Type of inhalation exposure:

nose only

Vehicle:

other: unchanged (no vehicle)

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Solid Aerosol Generator (SAG 410) (TOPAS GmbH, D-01279 Dresden, Germany) (for group 1) and a rotating brush powder disperser (Palas GmbH, Karlsruhe, Germany) and compressed air (for group 2 and 3)
- Method of holding animals in test chamber: the animals were held in polycarbonate restraint tubes located around the chamber which allowed only the animal‟s nases to enter the exposure port.
- Source and rate of air: Compressed air was supplied by means of an oil-free compressor and passed through a suitable filter system prior to introduction to the dust generator. The aerosol generated was supplied, using suitable tubing, to a glass particle-size separation (sedimentation) device before entering the exposure system (for group 1). The compressed air was supplied by an oil-less compressor and passed through respiratory quality filters and condensate traps prior to use. The aerosol generated was supplied, using suitable tubing, to a glass particle-size separation (sedimentation) device before entering the exposure system (for group 2 and 3)
- Method of particle size determination:
determined three times during the exposure period using a 7-stage impactor of Mercer style (TSE Systems GmbH, Bad Homburg, Germany). Such devices employ an inertial separation technique to isolate particles in the discrete aerodynamic size ranges. Samples were taken from an unoccupied exposure port (representing the animal‟s breathing zone). The collection substrates and the backup filter were weighed before and after sampling and the weight of test item, collected at each stage, calculated by difference. The total amount collected for each stage was used to determine the cumulative amount below each cut-off point size. In this way, the proportion (%) of aerosol less than 0.33, 0.5, 0.77, 1.21, 1.93, 3.13 and 5.09 m was calculated. From these data, using software supplied with the impactor (TSE Systems GmbH, Bad Homburg, Germany), the Mass Median Aerodynamic Diameter (MMAD), and Geometric Standard Deviation were calculated. In addition, the proportion (%) of aerosol less than 4m (considered to be the respirable portion) was determined.
- Temperature, humidity, pressure in air chamber: monitored continuously and recorded every minute during each exposure period by the TSE-DACO monitoring system integrated into the exposure system:


TEST ATMOSPHERE
- Brief description of analytical method used: The test atmosphere was sampled at regular intervals during each exposure period. Samples were taken from an unoccupied exposure port (representing the animal‟s breathing zone) by pulling a suitable, known volume of test atmosphere through weighed GF10 glass fibre filters (Schleicher & Schuell GmbH, Dassel, Germany or similar).
- Samples taken from breathing zone: yes


Animal exposure system:
The animals were exposed, nose-only, to an atmosphere of the test item using a TSE Rodent Exposure System (TSE Systems GmbH, Bad Homburg, Germany). This system comprises of two, concentric anodised aluminium chambers and a computer control system incorporating pressure detectors and mass flow controllers.
Fresh aerosol from the generation system was constantly supplied to the inner plenum (distribution chamber) of the exposure system from where, under positive pressure, it was distributed to the individual exposure ports. The animals were held in polycarbonate restraint tubes located around the chamber which allowed only the animal‟s nares to enter the exposure port. After passing through the animal‟s breathing zone, spent aerosol entered the outer cylinder from where it was exhausted through a suitable filter system. Atmosphere generation was therefore dynamic.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

group 1: 5,73 mg/L
group 2: 1,07 mg/L
group 3: 3,03 mg/L

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
mortality/viability: once daily during the acclimatisation phase, once before exposure on the day of exposure (test day1), once per hour during exposure, once after exposure on test day 1, and twice daily during the remainder of the observation period
body weights: recorded on test datys 1 (before exposure), 4, 8 and 15 (day of necroscopy) using a Mettler PM 4000 balance
clinical signs: once per hour during exposure (only grosly abnormal signs, as the animals were in restraint tubes), once after exposure on test day 1, and once daily thereafter
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight

Statistics:

log/probit method: to calculate the median lethal concentration values and 95% confidence intervals

Sex:

male/female

Dose descriptor:

LC50

Effect level:

2.71 mg/L air

Exp. duration:

4 h

Sex:

male

Dose descriptor:

LC50

Effect level:

2.53 mg/L air

Exp. duration:

4 h

Sex:

female

Dose descriptor:

LC50

Effect level:

2.87 mg/L air

Exp. duration:

4 h

Mortality:

The total deaths were respectively 10/10, 0/10 and 7/10 for group 1, 2 and 3

Clinical signs:

other: Wet fur and fur staining on various occasions were commonly recorded both during and for several hours after exposure. These observations were considered to be related to the restraint and exposure procedures and, in isolation, are considered not to be bi

Body weight:

The majority of surviving animals (9/13) during the observation period showed strong bodyweight losses, especially in the first week of the observation period.

Gross pathology:

Necroscopy:
Amongst animals that died during the course of the study, the following abnormalities were detected:
Lungs: dark red, edemic;
Trachea: foamy content;
Liver: congestion;
Kidneys: pale;
Intestines: empty;
Tracheobronchial lymph nodes: enlarged
Spleen: enlarged.
In the dead animals the alteration found in the lungs and in the liver (congestion) can be in connection with an acute circulatory insufficiency.
Amongst animals necropsied at terminal kill, the following macroscopic abnormalities were recorded:
Lungs – dark red, edemic, greyish-green colored areas;
Trachea: foamy content;
Kidneys: one-side pyelectasis;
Tracheobronchial lymph nodes: enlarged (bean sized), greyish-green colored;
Spleen: enlarged;
Uterus: slight hydrometra (in female animlas);
Nourishment: undernourishment;
Liver: congestion
In the surviving animals the hydrometra and the pyelectasis in an alteration with sporatic occurrence in experimental rats without toxicological meaning.
The alteration (dead and surviving animals too) found in the trachea, in the lungs (edemic, discoloration), in the tracheobronchial lymph nodes can be in connection with the effect of the test item. Macroscopic alteration in connection with the effect of the test item (CdTe) was found in the lungs and in the tracheobronchial lymph nodes.

Other findings:

none

none

Interpretation of results:

harmful

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Tests done according to standard protocol. Good quality and considered useful for setting the reference value for acute inhalation toxicity (LC50, 4h=2.7mg/L)

Executive summary:

The purpose of this study was to assess the acute inhalation toxicity of CdTe when administered to rats for a single continuous 4 -hour period, followed by an observation period of 14 days.

The acute inhalation median lethal concentrations (4hr LC50) (and 95% confidence limits) of CdTe, in Wistar Crl:(WI) BR strain rats, were calculated to be: All animals: 2.71 mg/L; Male only: 2.53 mg/L; Female only: 2.87 mg/L

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

An LC50 for acute inhalation toxicity of 2.7 mg CdTe/L was shown in the study of Nagy, 2008.
This study is disregarded as the test material is not representative for CdTe as put on the market.

Due to the granular nature of the powder >75µm, suitable test atmosphere could not be produced from the material as supplied. Prior to the use, therefore, the test item was ground using a VEB Elmo Ball mill. This raises the question of the representativeness of the tested substance in comparison to the form placed and subsequently used on the EU market.

The non-representative nature of milled CdTe was clearly shown in a series of Scanning Electron Microscopy (SEM) photographs of the cadmium telluride material as placed on the market, the isolated fine 'dust' and a simulated milled fraction of cadmium telluride (see IUCLID section 7.5.2 Repeated dose toxicity inhalation: attached doc 'CdTe inhalation waiver').

Therefore, due to the non-inhalable nature of cadmium telluride, it is proposed that the substance is not classified for the acute inhalation route

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Justification for classification or non-classification

Cadmium telluride is of very low acute oral and dermal toxicity not requiring a classification according to the EC criteria.

An LC50 for acute inhalation toxicity of 2.7 mg CdTe/L requires a classifcation as Actue Tox Cat 4; H332.

However, due to the granular nature of the powder >75µm, suitable test atmosphere could not be produced from the material as supplied. Prior to the use, therefore, the test item was ground using a VEB Elmo Ball mill. This raises the question of the representativeness of the tested substance in comparison to the form placed and subsequently used on the EU market.

The non-representative nature of milled CdTe was clearly shown in a series of Scanning Electron Microscopy (SEM) photographs of the cadmium telluride material as placed on the market, the isolated fine 'dust' and a simulated milled fraction of cadmium telluride (see IUCLID section 7.5.2 Repeated dose toxicity inhalation: attached doc 'CdTe inhalation waiver').

 

Therefore, due to the non-inhalable nature of cadmium telluride, it is proposed that the substance is not classified for the acute inhalation route.