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Repeated dose toxicity: inhalation

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Administrative data

Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
19 November 2013 - 27 January 2015
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Cross-reference
Reason / purpose:
reference to other study
Reference
Endpoint:
short-term repeated dose toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
30 September 2011 - 25 April 2013
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
comparable to guideline study with acceptable restrictions
Qualifier:
equivalent or similar to
Guideline:
OECD Guideline 412 (Subacute Inhalation Toxicity: 28-Day Study)
Principles of method if other than guideline:
This Dose Range Finding study was performed to obtain information on the toxicity of the test item cadmium telluride (CdTe) and to determine the Maximum Tolerated Concentration (MTC) when administered to Wistar rats via the inhalation route in the form of a dry aerosol for 28 days.
GLP compliance:
yes
Limit test:
no
Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633 Sulzfeld.
- Age at study initiation: 8-9 weeks approximately
- Weight at study initiation: not exceeded ± 20% of the mean weight for each sex at onset of treatment- Males: 212-272 g; females: 144-188 g
- Housing: Group caging (5 animals, by sex, per cage); Cage type: polycarbonate solid floor cages (type III) with stainless steel mesh lids.
- Diet : ssniff® SM R/M-Z+H “Autoclavable Complete Feed for Rats and Mice – Breeding and Maintenance” (Ssniff Spezialdiäten GmbH, D-59494 Soest Germany) ad libitum
- Water : tap water as for human consumption ad libitum
- Acclimation period: 19-20 d


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.1-25.0
- Humidity (%): 31-65
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
other: unchanged (no vehicle)
Mass median aerodynamic diameter (MMAD):
ca. 1.19 - ca. 2.61 µm
Geometric standard deviation (GSD):
2.39
Remarks on MMAD:
MMAD / GSD: MMAD = 1.19-2.61 µm (geometric standard deviation = 1.76-2.39
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:
Dust particles were produced using Palas RBG 1000 powder disperser (Palas®GmbH, 76229 Karlsruhe, Germany) located at the top of the exposure chamber. Dispersion was carried out by a high velocity air flow over the tightly woven precision brush. In order to improve aerodynamic size distribution, large particles were trapped by impaction in the subsequent simple pre-separator (double glass). For the low concentration (0.01 mgL) the pre-separation device was doubled.
- Method of holding animals in test chamber: nose-only exposure unit, in a TSE Rodent Exposure System with each individual concentration or control group in a dedicated tower. Four identical, modular multilevel flow - past nose-only exposure units (towers) were used.
- Method of particle size determination:
Particle size analysis of generated atmospheres was performed using a 7-stage cascade impactor of Mercer style (TSE Systems GmbH, Bad Homburg, Germany). Such devices employ an inertial separation technique to isolate particles into discrete aerodynamic size ranges. Samples were collected once a week at each concentration tested. Samples were collected from a vacant animal exposure port (animals breathing zone) and the resulting data used to calculate the mass median aerodynamic diameter (MMAD), Geometric Standard Deviation (GSD) and percentage < 4 µm (considered to be inhalable in the rat).
The collection substrates and the backup filter were weighed (analytical balance) before and after sampling and the weight of test item, collected at each stage, calculated by this 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 < 0.550, 0.550, 0.960, 1.550, 2.105, 3.555, 6.655 and 10.550 µm was calculated.
From these data, using the software supplied with the impactor (TSE Systems GmbH, Bad Homburg, Germany), the Mass Median Aerodynamic Diameter (MMAD), and Geometric Standard Deviation (GSD) were calculated. In addition, the proportion (%) of aerosol less than 3 µm was determined.
Results of the particle size analysis from the samples taken at the animal’s breathing zone indicated that the test atmospheres were respirable to the rats and should ensure particle deposition both in the upper and the lower respiratory tract.
- Air flow rate: Airflows and relative pressures within the system were constantly monitored and controlled by the computer system thus ensuring a uniform distribution and constant flow of fresh aerosol to each exposure port (breathing zone). The flow of air through each port was at least 0.5 L/min. This flow rate was considered adequate to minimise re-breathing of the test atmosphere and maintained oxygen concentrations at greater than 19% and a carbon dioxide concentration not exceeding 1%.
- Temperature, humidity, pressure in air chamber: test atmosphere temperature, relative humidity, oxygen and carbon dioxide concentration were considered to be satisfactory for this type of study.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Concentrations  were monitored automatically (measured concentrations within 85% of nominal conc)
Duration of treatment / exposure:
28 days
Frequency of treatment:
28 consecutive days, in continuous daily 6 hour sessions with exception of 3 mg/m3, exposed 2hours/day at 10 mg/m3
Dose / conc.:
0 mg/m³ air (analytical)
Dose / conc.:
3 mg/m³ air (analytical)
Dose / conc.:
10 mg/m³ air (analytical)
Dose / conc.:
30 mg/m³ air (analytical)
Dose / conc.:
90 mg/m³ air (analytical)
No. of animals per sex per dose:
 5 M and 5 F per dose 
Control animals:
yes
Details on study design:
- Dose selection rationale: The concentration levels were set by the Sponsor in consultation with the Study Director, based on available data from previous experimental work, including the results of a Dose range finding 7-day inhalation toxicity study (CiToxLAB study code 11/115-103PE), where the Maximum Tolerated Concentration (MTC) was found to be close to 0.05 mg/L with six hours exposure.
- Post-exposure recovery period in satellite groups: no
Positive control:
None
Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Checks were made twice daily, early and late during the normal working day, for mortality and/or morbidity amongst the test animals.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: As a minimum, individual, clinical observations were performed prior to exposure and twice during exposure whilst the animals were still restrained. Following exposure, clinical observation was performed twice (as soon as practicable after removal from restraint, and approximately one hour after completion of the exposure). Detailed clinical observations were made on all animals outside the home cage in a standard arena once a week.

BODY WEIGHT: Yes
- Time schedule for examinations: Body weight of each animal was recorded with a precision of 1 g at randomization, then on Day 0 (before the exposure), and twice a week thereafter and at the termination on Days 25/24 (High Dose animals) or Day 28 (prior to necropsy, fasted).
For the High Dose females, the terminal (Day 24) body weight values were used for statistical evaluation, as the values were similar to these obtained one day earlier, on Day 23.
Body weights were recorded at death, for animals found dead during the course of the study.


FOOD CONSUMPTION:
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Food consumption was recorded with precision of 1 g weekly.

HAEMATOLOGY: Yes

CLINICAL CHEMISTRY: Yes .

URINALYSIS: Yes
Urinalysis was performed during the last week of the study. Urine samples were collected for 16 hours during an overnight period of food deprivation. Animals were placed in metabolic cages during collection. The evaluation of the urine samples was performed by observation or test strips as applicable.

NEUROBEHAVIOURAL EXAMINATION: Yes / No / No data
- Time schedule for examinations:
- Dose groups that were examined:
- Battery of functions tested: sensory activity / grip strength / motor activity / other:

Sacrifice and pathology:
GROSS PATHOLOGY: Yes
organ weight measurements
bronchoalveolar lavage
tissue preservation and microscopic evaluation
Statistics:
The heterogeneity of variance between groups was checked by Bartlett’s homogeneity of variance test. Where no significant heterogeneity is detected, a one-way analysis of variance was carried out. If the obtained result is positive, Duncan’s Multiple Range test was used to assess the significance of inter-group differences. Where significant heterogeneity is found, the normal distribution of data was examined by Kolmogorov-Smirnov test. If the data is not normal distributed, the non-parametric method of Kruskal-Wallis One-Way analysis of variance was used. If there is a positive result, the inter-group comparisons was performed using Mann-Whitney U-test. The frequency of clinical observations and necropsy and histopathology findings were calculated as applicable.
Clinical signs:
effects observed, treatment-related
Mortality:
mortality observed, treatment-related
Body weight and weight changes:
effects observed, treatment-related
Food consumption and compound intake (if feeding study):
effects observed, treatment-related
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
effects observed, treatment-related
Clinical biochemistry findings:
effects observed, treatment-related
Urinalysis findings:
effects observed, treatment-related
Behaviour (functional findings):
not specified
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Gross pathological findings:
effects observed, treatment-related
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Histopathological findings: neoplastic:
not specified
Details on results:
CLINICAL SIGNS AND MORTALITY:
mortality:Exposure to the test atmosphere at 0.09 mg/L (High Concentration Group) six hours/day, caused the loss of two animals and the premature termination of the exposure due to ethical reasons in Week 4. (Study Days 24 and 23, males and females, respectively).
clinical signs:
The main clinical sign was increased respiratory rate (tachypnea) and was observed throughout the study with dose related incidence and severity. The incidence and severity increased with the duration of the study.
At 0.09 mg/L (Group 5) slight tachypnea appeared first on Day 0 following the exposure in single animals, in week 2 was noted as moderate, and thereafter became severe and permanent. Additionally, from Day 21 (males) and Day 15 (females), slight to moderate decreased activity was observed. Due to continuous body weight loss, the animals became thin from Day 17/14 (males/females) and some of them cachectic by the termination of the study.
In found dead animals, in addition, partially closed eyelids and, in the male, signs of hematuria (e.g. red/brown staining of the fur at urogenital area) were observed.
In animals exposed to a concentration of 0.03 mg/L for six hours (Group 4), slight/moderate tachypnea was observed from Day 12-15 in few animals, with increasing severity and incidence on following days. Persistent moderate tachypnea was observed in males from Day 26 and in females (slight to moderate) from Day 17 up to the termination of the study.
At 0.01 mg/L (Group 3, six-hour exposure), slightly increased respiratory rate was first observed on Day 19/20 in single female and male during/following the exposure, moderate tachypnea was observed on Day 24 in males and from Day 22 in females, and the sign became persistent in females only, from Day 25 up to the termination of the study.
In the animals exposed at 0.003 mg/L (Group 2), slightly increased respiratory rate was observed following the exposure from Day 20. Following the last exposure on Day 27, moderate tachypnea was observed in 2 of 5 females.
Ruffled coat was noted in all animals including controls, however, with higher incidence in Groups 4 and 5.
Wet fur and fur staining were commonly recorded during and following the exposure. These observations were considered to be related to the restraint and exposure procedures and were considered not to be toxicologically significant.


BODY WEIGHT AND WEIGHT GAIN:
Test item related effects on body weight was observed in both males and females exposed at (0.03 and 0.09 mg/L).
Permanent body weight loss was observed at 0.09 mg/L (High Concentration Group) and was up to 23% in males and 29% in females at the termination of the treatment on Day 24 or 23, compared to the initial values.
At 0.03 mg/L (Mid Concentration) moderate body weight gain suppression was observed in males throughout the exposure period, while in females following a severe body weight gain suppression on weeks 2 and 3, slight body weight loss was recorded in week 4.
The lower mean body weight was in accordance with the decreased food consumption in Groups 4 and 5.
At 0.01 mg/L (Mid-low Concentration), minimal body weight gain suppression was noted in males; however, the mean body weight value was comparable with the control. No effect was observed in females in this group.
The mean body weight and body weight gain of males and females in Group 2 (Low Concentration, 0.003 mg/L) were comparable to the control values during the 4-week exposure period.


FOOD CONSUMPTION:
There was a significant decrease in food consumption in both males and females in Groups 4 and 5, (exposed at 0.03 and, 0.09 mg/L for six hours). The lower food consumption was in accordance with the effect on body weight.

Slightly lower mean food consumption was recorded for Group 3 females during the last week of the exposure.

In both males and females in Group 2 (Low Concentration, 0.003 mg/L), no adverse effect was observed on food consumption.


HAEMATOLOGY:
Changes in hematology were found mostly in groups exposed at 0.03 and 0.09 mg/L (Mid and High Concentration) and consisted of slightly increased red blood cell (RBC) count, hemoglobin (HGB) concentration and hematocrit (HCT) value in both males and females, decreased reticulocyte count in males and females at 0.09 mg/L, increased neutrophil granulocyte count with concomitant decrease in lymphocyte count in both males and females (relative values were evaluated), increased monocyte count in males and decreased platelets count in females at 0.09 mg/L.

CLINICAL CHEMISTRY:
Test item related clinical chemistry findings occurred mostly at 0.09 mg/L and consisted of increased activity of Aspartate Aminotransferase (AST), Alkaline Phosphatase (ALKP) and Gamma Glutamyltransferase (GGT) in both males and females. AST and ALKP activity was also slightly increased at 0.03 mg/L. Albumin concentration was decreased in both males and females at 0.09 mg/L, with concomitant increase in Calcium (Ca++) concentration, decreased albumin to globulin (A/G) ratio and lower creatinine concentration. Sodium (Na+) concentration was increased in both males and females at 0.03 and 0.09 mg/L. Blood urea concentration was slightly increased in females at 0.01, 0.03 and 0.09 mg/L.

URINALYSIS:
The urinalysis parameters were comparable to the controls in both males and females in Groups 2, 3 and 4 (exposed at 0.003, 0.01 and 0.03 mg/L, respectively). The mild differences were recorded in the urine volume in females in Groups 3 and 4 (p<0.05), i.e. compared with the control, smaller samples were collected for some of the females, however without any changes in the specific gravity values. The finding was not directly attributable to the test item exposure. Protein content was detected in all samples from both males and females in Group 4 (exposed at 0.03 mg/L), however this finding was noted with lower incidence also in the control animals. It should be noted, that for the animals in Group 5 (exposed at 0.09 mg/L) due to insufficient sample collection only few urine samples were examined.


ORGAN WEIGHTS:
Adrenal weights were lower in both sexes (by approximately 20-30%) at 0.09 mg/L and ovary weights were decreased at 0.03 and 0.09 mg/L.
Liver and kidney weights were decreased by approximately 30%, and 15-25% respectively at 0.09 mg/L, and were considered to be secondary effect related to the significant body weight loss of the animals.
Weights of lungs were dose dependently increased in all test atmosphere exposed animals, and were approximately 1.5-2 times higher in the Low Concentration Group and up to 3 times higher at 0.09 mg/L.

GROSS PATHOLOGY:
Inflammatory changes in lungs of all treated animals were detectable in bronchoalveolar lavage (BAL) in the form of increased activity of lactate dehydrogenase and protein concentration.

HISTOPATHOLOGY: NON-NEOPLASTIC:
Gross observation and increase in weight of lungs correlated microscopically with alveolar/interstitial/bronchiolar inflammation and hyperplasia of Type II pneumocytes and black pigment in the cytoplasm of macrophages. In addition, at 0.03 and 0.09 mg/L, interstitial fibroplasia was observed. The lung changes were accompanied by dose related, minimal to moderate hyperplasia and degeneration/necrosis of the macrophage in the lung-associated lymph nodes at 0.01, 0.03 and 0.09 mg/L. At a concentration of 0.003 mg/L (achieved by exposure to 0.01 mg/L for two hours) minimal alveolar/interstitial/bronchiolar inflammation, minimal hyperplasia of the Type II pneumocytes and minimal lymphoid hyperplasia of the lung-associated lymph nodes was experienced.
Decreased thymus weight in exposed animals correlated microscopically with lymphoid atrophy, and with reduced peripheral lymphocyte counts detected during hematological examination.
In the testes of exposed animals minimal, multifocal, tubular atrophy and in the epididymes minimal hypospermia were observed.


Dose descriptor:
LOAEL
Effect level:
3 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
other: adverse effects on respiratory tract
Critical effects observed:
not specified

None

Conclusions:
CdTe administered to Han Wistar rats as dry aerosol by the inhalation route, daily for 28 days at the lowest possible concentration of 0.01 mg/L for 2 hours was considered to have an adverse effect on the respiratory tract. Therefore the no observed adverse effect-level (NOAEL) was not found in this study.
Executive summary:

An exposure to the Cadmium telluride (CdTe) in the form of a dry aerosol to Wistar rats for up to 28 consecutive days at concentration levels of 0.003, 0.01, 0.03 and 0.09 mg/L was associated with following effects:

-Exposure to the test atmosphere at 0.09 mg/L for six hours/day, caused the loss of two animals and early termination of the exposure due to ethical reasons on Week 4.(Study Days 24 and 23, males and females, respectively). Exposure resulted in severe tachypnea (increased respiratory rate) and decreased activity, expressed body weight loss and reduced food consumption. Changes in hematology and clinical chemistry parameters reflected poor condition of the animals, however changes in some of the parameters might be indicative for liver and kidney impairment. An increase in lung weights (2-3 times versus control) was associated with mild to moderatealveolar/interstitial inflammation,mild to moderate interstitial fibroplasia and degeneration/necrosis of the macrophages in the lung associated lymph nodes. Weight of the thymus was markedly decreased.

-Exposure at 0.03 mg/L for six hours was associated with slight/moderate tachypnea, moderate body weight gain suppression and/or in females slight temporary body weight loss and minimal changes in a few clinical chemistry parameters. An increase in lung weights (2-3 times versus control), correlated with minimal to mild alveolar/interstitial/bronchiolar inflammation, minimal to mild interstitial fibroplasiasand degeneration/necrosis of the macrophages in the lung-associated lymph nodes.

-Exposure at 0.01 mg/L for six hours resulted in slight tachypnea, minimal body weight gain suppression in males and an increase in lungs weight (2-2.7 times versus control), which correlated with minimal alveolar/interstitial/bronchiolar inflammationand minimal degeneration/necrosis of the macrophages in the lung-associated lymph nodes.

-Exposure at 0.003 mg/L (achieved by exposure of 0.01 mg/L for two hours) was associated with slight, transient tachypnea during the last week of the exposure, increase in lungs weights (by about 1.5-2 times), which correlated with minimal alveolar/interstitial/bronchiolar inflammation and minimal hyperplasia of the Type II pneumocytes .

 

In conclusion, under the conditions of this study, CdTe administered to Han Wistar rats as dry aerosol by the inhalation route, daily for 28 days at the lowest possible concentration of 0.01 mg/L for 2 hours was considered to have an adverse effect on the respiratory tract. Therefore the no observed adverse effect-level (NOAEL) was not found in this study.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2015
Report Date:
2015

Materials and methods

Test guideline
Qualifier:
according to
Guideline:
OECD Guideline 412 (Subacute Inhalation Toxicity: 28-Day Study)
GLP compliance:
yes
Limit test:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
aerosol dispenser: not specified
Remarks:
migrated information: aerosol
Details on test material:
Name: Cadmium telluride
Short name (used for raw data): CdTe
Batch number: 138683 and 163568
CAS number: 1306-25-8
Appearance: Black solid
Purity: > 99.99%
Expiry date: 2 years from the first opening (24 May 2013, 05 November 2013, resp.) if kept under inert atmosphere (e.g. nitrogen)
Storage conditions: at Room Temperature (15 - 30ºC) under inert gas (e.g. nitrogen)
Use of the substance: Photovoltaic modules and semiconductor industry
Safety Precautions: Routine safety precautions (gloves, goggles, lab coat) for unknown materials were applied to assure personnel health and safety. For respiratory protection, face mask with P3R particulate filter were used. Precautions required in handling are outlined in the Material Safety Data Sheet.

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, D-97633 Sulzfeld.
- Age at study initiation: less than 9 weeks old at the initiation of treatment
- Weight at study initiation: At initiation of treatment: (Main and Recovery) Males: 199-226 g; Females: 149-180 g- The weight variation in groups did not exceed ± 20% of the mean weight for either sex
- Housing: Group caging (up to 3 animals, by sex, per cage, (i.e.3+2 main and recovery and 2 satellite) Cage type: Polycarbonate solid floor cages (type III) with stainless steel mesh lids.
- Diet : ssniff® SM R/M-Z+H “Autoclavable Complete Feed for Rats and Mice – Breeding and Maintenance” (Ssniff Spezialdiäten GmbH, D-59494 Soest Germany) ad libitum
- Water : tap water as for human consumption ad libitum
- Acclimation period: At least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 20.0-25.0°C
- Humidity (%): 34-54 %
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12/12

Administration / exposure

Route of administration:
inhalation: aerosol
Type of inhalation exposure:
nose only
Vehicle:
other: unchanged (no vehicle)
Mass median aerodynamic diameter (MMAD):
ca. 1.08 - ca. 1.8 µm
Geometric standard deviation (GSD):
2.78
Remarks on MMAD:
MMAD / GSD: MMAD = 1.08-1.80 μm (geometric standard deviation = 1.75-2.78)

Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:
An extended technical trial was carried out before animals were exposed. During this period, airflow settings, test item input and the atmosphere generation system was adopted to achieve the required atmospheric concentration of 1 μg/mL and of good constancy. Palas RBG 1000 powder disperser (Palas®GmbH, 76229 Karlsruhe, Germany) was selected as the most appropriate generator for the study purpose. Dispersion of the test item was carried out by a high velocity air flow over the
tightly woven precision brush. In order to improve test atmosphere quality, before entering the exposure system the test aerosol was optimised by passing though subsequent pre-separation and dilution devices.
- Method of holding animals in test chamber: nose-only exposure unit, in a TSE Rodent Exposure System for exposure of test item atmosphere or control group in dedicated towers. Two modular multilevel flow-past nose only exposure units (towers) were used.
- Method of particle size determination:
An aerosol atmosphere was generated to contain particles with a mass median aerodynamic diameter (MMAD) between 1 to 3 μm with a geometric standard deviation (δg) in the range of 1.5 to 3.
Particle size analysis of generated atmospheres was performed using a 7-stage cascade impactor of Mercer style (TSE Systems GmbH, Bad Homburg, Germany). Such devices employ an inertial separation technique to isolate
particles into discrete aerodynamic size ranges. Samples were collected at least once a week at each concentration tested. Samples were collected from a vacant animal exposure port (animals breathing zone) and the resulting data
used to calculate the mass median aerodynamic diameter (MMAD), Geometric Standard Deviation (GSD) and percentage < 4 μm (considered to be inhalable in the rat).
Test item deposition on each stage was measured by gravimetric analysis and confirmed by ICP analysis for Cd by ICP/MS method (determination of cadmium content) as appropriate at the Test Site.
- Air flow rate: Airflows and relative pressures within the system were constantly monitored and controlled by the computer system thus ensuring a uniform distribution and constant flow of fresh aerosol to each exposure port (breathing zone). The flow of air through each port was at approximately 1 L/min. This flow rate is considered adequate to minimise re-breathing of the test atmosphere and to maintain oxygen concentrations at greater than 19% and a carbon dioxide
concentration not exceeding 1%.
- Temperature, humidity, pressure in air chamber: test atmosphere temperature, relative humidity, oxygen and carbon dioxide concentration were considered to be satisfactory for this type of study.
Analytical verification of doses or concentrations:
yes
Details on analytical verification of doses or concentrations:
Concentrations  were monitored automatically (measured concentrations within 85% of nominal conc)
Duration of treatment / exposure:
28 days
Frequency of treatment:
28 consecutive days, in continuous daily 6 hour sessions; but 0.3 and 0.1 mg/m3 achieved by exposure to the test atmosphere concentration of 1 mg/m3 for 2 hours/day and 40 min/day, respectively.
Doses / concentrationsopen allclose all
Dose / conc.:
0 mg/m³ air (analytical)
Dose / conc.:
0.1 mg/m³ air (analytical)
Dose / conc.:
0.3 mg/m³ air (analytical)
Dose / conc.:
1 mg/m³ air (analytical)
No. of animals per sex per dose:
- 5 males and 5 females in 4 Main groups (control and 3 test item-treated groups) sacrificed one day following the last exposure on Day 28
- 5 males and 5 females in 2 Recovery groups (control and High dose groups) sacrificed following 14-day treatment free observation period
Control animals:
yes
Details on study design:
- Dose selection rationale: The concentration levels of 0.1, 0.3 and 1 μg/L were set by the Sponsor in consultation with the Study Director, based on available data from previous experimental work, including the results of previous, 28-day inhalation study (CitoxLAB study code 11/115-103P) (Grosz et al 2013, Cadmium telluride ( CdTe ): 28-Day Dose Range Finding Inhalation Toxicity Study (Nose-only) in the Rat" (CiToxLAB Hungary Ltd. study code: 11/115-103P, 2013)).
In this study, rats were exposed to the test atmospheres achieved by dispersion of ground CdTe in air, for 6 hours/day. The lowest dose level of 0.003 mg/L (achieved from 0.01 mg/L by reduction of the exposure duration to 2 hours) was associated with adverse effects in the respiratory tract in the form of increase in lungs weight (by approximately 1.5-2 times) correlated with minimal alveolar/interstitial /bronchiolar inflammation, minimal hyperplasia of the Type II. pneumocytes
and minimal lymphoid hyperplasia of the lung-associated lymph nodes. The NOAEL was not determined in this preceding study.
- Post-exposure recovery period in satellite groups: yes
Positive control:
None

Examinations

Observations and examinations performed and frequency:
CAGE SIDE OBSERVATIONS: Yes
- Time schedule:Checks were made twice daily, early and late during the normal working day, for mortality and/or morbidity amongst the test animals.

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Individual clinical observations were performed prior to exposure and twice during exposure whilst the animals are still restrained. Following exposure clinical observation was performed twice (as soon as practicable after removal from restraint, and approximately one hour after completion of the exposure). Detailed clinical observations were made on all animals outside the home cage in a standard arena once a week.
The animals were observed for changes in 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. All changes were recorded.

BODY WEIGHT: Yes
- Time schedule for examinations: The body weight of each animal was recorded with a precision of 1 g at randomization, then on Day 0 (before the exposure), twice a week thereafter and on Days 28 and 42 (prior to necropsy, fasted).

FOOD CONSUMPTION: YES
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: Yes
Food consumption was recorded with precision of 1 g weekly.

HAEMATOLOGY: Yes
- Time schedule for collection of blood:
At the end of the treatment or recovery periods, prior to scheduled necropsy on Day 28 or 42, blood samples for clinical pathology evaluation (haematology,
coagulation, and clinical biochemistry) were collected by heart puncture under pentobarbital anaesthesia.
After an overnight period of food deprivation of animals, 3 blood samples were collected, for haematology (approximately 1.2 mL blood in tubes with K3-EDTA as anticoagulant, 1.6 mg/mL blood), for blood clotting times
(approximately 1.4 mL blood for APTT and PT measurements, in tubes with sodium citrate as anticoagulant) and one to obtain serum (approximately 1 mL blood as practical in tubes with no anticoagulant) for clinical chemistry.
- Animals fasted: Yes


CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: At the end of the treatment or recovery periods, prior to scheduled necropsy on Day 28 or 42, blood samples for clinical pathology evaluation (haematology,
coagulation, and clinical biochemistry) were collected by heart puncture under pentobarbital anaesthesia.
After an overnight period of food deprivation of animals, 3 blood samples were collected, for haematology (approximately 1.2 mL blood in tubes with K3-EDTA as anticoagulant, 1.6 mg/mL blood), for blood clotting times
(approximately 1.4 mL blood for APTT and PT measurements, in tubes with sodium citrate as anticoagulant) and one to obtain serum (approximately 1 mL blood as practical in tubes with no anticoagulant) for clinical chemistry.
- Animals fasted: Yes
- Parameters checked in table [YES] were examined: Glucose ; T-BIL ; Urea ; Chol. ; Creat. ; Trig. ; Phos. ; Na+ ; K+ ; Ca++ ; Cl- ; Tot. Prot. ; Alb. ; A/G ; AST/GOT ; ALT/GPT ; ALKP Alkaline. Phosphatase – activity; GGT Gamma Glutamyltransferase -activity : Bile acids


URINALYSIS: Yes
Urinalysis was performed prior to scheduled necropsy on Days 28 and 42. Urine samples were collected for 16 hours during an overnight period of food deprivation. Animals were placed individually in metabolic cages during
collection. The evaluation of the urine samples was performed by observation (e.g. appearance, colour) or test strips as applicable.

NEUROBEHAVIOURAL EXAMINATION: No

Sacrifice and pathology:
GROSS PATHOLOGY: Yes
organ weight measurements
bronchoalveolar lavage
tissue preservation and microscopic evaluation
Statistics:
The heterogeneity of variance between groups was checked by Bartlett’s homogeneity of variance test. Where no significant heterogeneity was detected, a one-way analysis of variance was carried out. If the obtained result was positive, Duncan’s Multiple Range test was used to assess the significance of inter-group differences. Where significant heterogeneity was found, the normal distribution of data was examined by Kolmogorov-Smirnov test. If the data was not normal distributed, the non-parametric method of Kruskal-Wallis One-Way analysis of variance was used. If there was a positive result, the intergroup comparisons were performed using Mann-Whitney U-test. For recovery groups T test was used.

Results and discussion

Results of examinations

Clinical signs:
effects observed, non-treatment-related
Description (incidence and severity):
No clinical signs of toxicological importance were noted in any of the experimental group.
Ruffled fur was occasionally observed in single animals in all test item exposed animals and in control males. This observation was considered to be procedure related. Additionally, red-brown staining of the fur on the nose/snout, around eyes and on the head was observed in the test item exposed animals and control.
This clinical sign, related to porphyrin discharge was considered to be a common observation in animals treated by the inhalation route.
A staining of the fur by test item was noted following the exposure mostly in animals exposed for 6 hour/day in both sexes.
Wet fur was commonly recorded in both test item exposed animals and control. This observation was considered to be related to the restraint and exposure
procedures and not to be toxicologically significant.
During a 14-day recovery period the animals were symptom-free.
Mortality:
no mortality observed
Body weight and weight changes:
no effects observed
Food consumption and compound intake (if feeding study):
no effects observed
Food efficiency:
not specified
Water consumption and compound intake (if drinking water study):
not specified
Ophthalmological findings:
not specified
Haematological findings:
effects observed, treatment-related
Description (incidence and severity):
· Increase in neutrophil granulocyte count in all exposed males and in females in Mid and High dose (exposure levels of 0.3 and 1 mg/L, respectively) groups on Day 28 and in high dose groups following recovery period (Day 42). The differences attained statistical significance, except males on 42 day.
· Decrease in lymphocyte percentage in all exposed males and in females in Mid and High dose (exposure slevels of 0.3 and 1 mg/L, respectively) groups on Day 28 and in high dose groups following recovery period (Day 42), without any significant changes in absolute number, however slightly higher values were measured for females on Day 28. The change in percentage was a consequence of increase in neutrophil granulocyte.
· A minimal increase in total white blood cells (WBC) count in both males and females in Mid and High dose (exposure levels of 0.3 and 1 mg/L, respectively) groups on Day 28 and in High dose recovery groups. The differences to control attained statistical significance for females on Day 28, only.
· Decreased platelet count in High dose (exposure level of 1 mg/L) females, on Day 42 (p<0.05). On Day 28 the values were at control level, and the relatively higher control mean value on was attributable to one female (151) with individual value of 1042 K/mL. It should be noted, that the differences were of low magnitude, and all values, including control were relatively low.
Clinical biochemistry findings:
effects observed, non-treatment-related
Description (incidence and severity):
Clinical chemistry evaluation did not reveal any obvious toxicity for test item following 28-day exposure at any of dose levels.
Compared to controls, high dose females (exposure of 1 mg/L) had slightly higher mean calcium, phosphorus and sodium concentration on Day 28 and the
differences attained statistical significance. Slightly higher mean phosphorus concentration was measured also for Mid dose, while
sodium concentration for low dose females (exposure levels of 0.3 and 0.1 mg/L, respectively).
As the mean and individual values remained within the normal ranges, the changes were not considered toxicologically significant.
Following the end of the recovery period, these parameters did not differ from the control mean.
No statistically significant changes were recorded for these parameters in the males.
Urinalysis findings:
effects observed, non-treatment-related
Description (incidence and severity):
No effects were noted, which could be related to the test item.
Statistical differences were recorded in the urine volume in females on Day 42 (p<0.05), however, without any changes in the specific gravity values. This
finding was attributable to the relatively smaller samples collected for some of the control females.
Results of sediment analysis revealed no significant differences between control and treated animals.
Behaviour (functional findings):
not specified
Immunological findings:
not specified
Organ weight findings including organ / body weight ratios:
effects observed, treatment-related
Description (incidence and severity):
Dose dependent increase in lungs weight (absolute and relative values) was noted in both sexes in all treated groups on Days 28 and 42. Increase was in the range of approximately 35-45% (males) and 20-24% (females) in the Low dose group, 50-65% in Mid dose group and 94-106% in the High dose, compared to control mean. Following the recovery period, the mean lungs weights were in the range of 120-126% and 106-110% in males
and females, respectively.
The changes in organ weights correlated with macroscopic observations, i.e. enlarged, gray mottled lungs with enlarged and gray coloured lung-associated lymph nodes (high dose Days 28 and 42), enlarged lungs and the lungassociated lymph nodes (mid dose) and enlarged lung-associated lymph nodes (low dose).

Gross pathological findings:
effects observed, treatment-related
Description (incidence and severity):
Enlarged, gray mottled lungs with enlarged and gray coloured lung-associated lymph nodes (high dose Days 28 and 42), enlarged lungs and the lung associated lymph nodes (mid dose) and enlarged lung-associated lymph nodes
(low dose).
Neuropathological findings:
not examined
Histopathological findings: non-neoplastic:
effects observed, treatment-related
Description (incidence and severity):
Evaluation of bronchoalveolar lavage (BAL) fluid on Day 28, revealed inflammatory changes in the form of dose dependent increase in total cell
counts (all exposed groups) and significant increase in lactate dehydrogenase (LDH) activity, protein concentration in Mid and High dose (exposure level of
0.3 and 1 µg/L, respectively) groups. Similar alterations were noted on Day 42.
Microscopically diffuse alveolar/interstitial inflammation was observed in lungs at all exposure levels. The changes were minimal in Low dose groups
and were noted in 4 of 5 males and 4 of 5 females, while minimal to mild inflammation was observed in all animals in the Mid and High groups, with
slightly increased severity in high dose animals.
Additionally, minimal accumulation of alveolar foamy macrophages and minimal to mild cytoplasmic deposits of black pigment in interstitial macrophages were observed with dose dependent manner in Mid and High dose (exposure level of 0.3 and 1 µg/L, respectively) groups in both sexes.
In the lung-associated lymph nodes mild to moderate lymphoid hyperplasia, aggregates of macrophages and presence of black pigment in macrophages
were noted at all exposure levels. Minimal to mild degeneration/necrosis of the macrophages was noted in the lung-associated lymph nodes at Mid and High
dose (exposure level of 0.3 and 1 µg/L, respectively) groups.
Following recovery period changes in the lungs and lung-associated lymph nodes were still present, although severity of diffuse alveolar/interstitial
inflammation of lungs slightly increased, which was expected consequence of the slow clearance of particles from lungs.

Histopathological findings: neoplastic:
not specified
Details on results:
CLINICAL SIGNS AND MORTALITY:
mortality: no mortality at any of the exposure level.
clinical signs:
No clinical signs of toxicological importance were noted in any of the experimental group.

BODY WEIGHT AND WEIGHT GAIN:
No effect on body weight was observed in any of the test item exposed groups.

FOOD CONSUMPTION:
No effect on food consumption was observed in any of the test item exposed groups.

HAEMATOLOGY:
Dose dependent increase in neutrophil granulocyte count was observed in all exposed males and in Mid and High dose females (exposure level of 0.3 and 1 mg/L, respectively) on Day 28 and in High dose (1 mg/L) groups following recovery period (Day 42).

Decrease in lymphocyte percentage in all exposed males and in females in Mid and High dose (exposure slevels of 0.3 and 1 mg/L, respectively)
groups on Day 28 and in high dose groups following recovery period (Day 42), without any significant changes in absolute number, however
slightly higher values were measured for females on Day 28. The change in percentage was a consequence of increase in neutrophil
granulocyte.

A minimal increase in total white blood cells (WBC) count in both males and females in Mid and High dose (exposure levels of 0.3 and
1 mg/L, respectively) groups on Day 28 and in High dose recovery groups. The differences to control attained statistical significance for
females on Day 28, only.

Decreased platelet count in High dose (exposure level of 1 mg/L) females, on Day 42 (p<0.05). On Day 28 the values were at control
level, and the relatively higher control mean value on was attributable to one female (151) with individual value of 1042 K/mL. It should be
noted, that the differences were of low magnitude, and all values, including control were relatively low.

There were no test item related adverse effects in blood clotting, clinical chemistry or urinalysis parameters at any dose level.

CLINICAL CHEMISTRY:
Clinical chemistry evaluation did not reveal any obvious toxicity for test item following 28-day exposure at any of dose levels.

URINALYSIS:
No effects were noted, which could be related to the test item.

ORGAN WEIGHTS:
Dose dependent increase in lungs weight (absolute and relative values) was noted in both sexes in all treated groups on Days 28 and
42. Increase was in the range of approximately 35-45% (males) and 20-24% (females) in the Low dose group, 50-65% in Mid dose group and 94-106% in
the High dose, compared to control mean. Following the recovery period, the mean lungs weights were in the range of 120-126% and 106-110% in males
and females, respectively.
The changes in organ weights correlated with macroscopic observations, i.e. enlarged, gray mottled lungs with enlarged and gray coloured lung-associated
lymph nodes (high dose Days 28 and 42), enlarged lungs and the lungassociated lymph nodes (mid dose) and enlarged lung-associated lymph nodes
(low dose).

GROSS PATHOLOGY:
Enlarged, gray mottled lungs with enlarged and gray coloured lung-associated lymph nodes (high dose Days 28 and 42), enlarged lungs and the lung associated lymph nodes (mid dose) and enlarged lung-associated lymph nodes (low dose).

HISTOPATHOLOGY: NON-NEOPLASTIC:
Changes in the lungs were characterized by minimal to mild diffuse alveolar/interstitial inflammation and occurred in all test item exposed groups.
The changes were minimal in Low dose (exposure level of 0.1 µg/L) groups and were noted in 4 of 5 males and 4 of 5 females. In Mid and High dose
groups (exposure level of 0.3 and 1 µg/L, respectively), the alveolar/interstitial inflammation was classified as minimal to mild diffuse change and was
observed in all animals in these groups, with slightly increased severity in high dose animals.

In addition, minimal accumulation of alveolar foamy macrophages and minimal to mild cytoplasmic deposits of black pigment in interstitial
macrophages was observed in Mid and High dose (exposure level of 0.3 and 1 µg/L, respectively) groups in both sexes. The severity of these changes
suggested dose dependency. Pulmonary inflammatory changes were consistent with the BAL fluid findings.
Dose dependence was also noted in changes in the lung-associated lymph nodes. Clearance of test item particles from the lung to the lung-associated
lymph nodes resulted only in lymphoid hyperplasia and minimal/mild degeneration/necrosis of the macrophages at the highest doses.
In all test item exposed groups mild to moderate lymphoid hyperplasia in the cortex/paracortex, aggregates of macrophages in the paracortex/medulla and
the presence of black pigment in macrophage cytoplasm, were detected, while minimal to mild degeneration/necrosis of the macrophages was observed in
Mid and High dose (exposure level of 0.3 and 1 µg/L, respectively) groups in both sexes.
After the recovery period, changes in the lungs and lung-associated lymph nodes were still present.
Mild to moderate diffuse alveolar/interstitial inflammation of the lungs occurred in all High dose animals (1 µg/L). It should be noted that moderate
intensity was not microscopically detected in animals sacrificed on Day 28.
Minimal accumulation of alveolar foamy macrophages (9/10) and minimal to moderate black pigment in the cytoplasm of interstitial macrophages (10/10)
were present in the Recovery High dose animals. These changes were considered as expected consequence of the slow clearance of insoluble
particles from lungs.
Moderate lymphoid hyperplasia in the cortex/paracortex and aggregates of macrophages in the paracortex/medulla in the lung-associated lymph nodes
were detected in all High dose animals, in addition to the presence of black pigment in the cytoplasm of macrophages (10/10) and minimal to mild
degeneration/necrosis of the macrophages (10/10).



Effect levels

Dose descriptor:
LOAEL
Effect level:
0.1 mg/m³ air
Based on:
test mat.
Sex:
male/female
Basis for effect level:
histopathology: non-neoplastic
other: adverse effects on respiratory tract
Remarks on result:
other: 0.1 mg/m3 air achieved by exposure to 1mg/m3 for 40 minutes)

Target system / organ toxicity

Critical effects observed:
not specified

Any other information on results incl. tables

None

Applicant's summary and conclusion

Conclusions:
CdTe administered to Han Wistar rats as dry aerosol by the inhalation route, daily for 28 days at the lowest possible concentration of 1 µg/L for 40 minutes was considered to have a minimal adverse effect on the respiratory tract. The no observed adverse effect-level (NOAEL) is below this exposure level.
Executive summary:

An exposure to the Cadmium telluride (CdTe) in the form of a dry aerosol to Hannover Wistar rats for 28 consecutive days at concentration of 1 mg/L for 6 hour and 0.3 μg/L (achieved by exposure to the 1.0 μg/L for two hours) was associated with enlarged, gray mottled lungs and enlarged, gray coloured lung associated lymph, increase in lungs weight (absolute and relative values) in both sexes by approximately 94-106% (at 1 mg/L) and 50-65% (0.3 mg/L), correlated with minimal to mild diffuse alveolar/interstitial inflammation, accumulation of foamy alveolar macrophages and black cytoplasmic pigment in interstitial macrophages of the lungs. Additionally, lymphoid hyperplasia and aggregates of macrophages, presence of black pigment in macrophages and degeneration/necrosis of the macrophages were found in the lung associated

lymph nodes. Inflammatory changes of lungs were detectable by bronchoalveolar lavage and increase in neutrophil granulocyte count in peripheral blood detected at haematology. Changes were still present following 14-day treatment free period.

Exposure at 0.1 μg/L (achieved by exposure to the 1.0 μg/L for 40 minutes) resulted in increase of lungs weight by approximately 35-45% (males) and 20 -24% (females), without any macroscopic observation, except enlarged lung associated lymph nodes. Microscopically minimal diffuse alveolar/interstitial inflammation was observed in lungs in 4 of 5 males and 4 of 5 females, in addition to mild changes in lung-associated lymph nodes (mild lymphoid hyperplasia and aggregates of macrophages, presence of black pigment).

In conclusion, under the conditions of this study, CdTe administered to Hannover Wistar rats as dry aerosol by the inhalation route, daily for 28 days at the lowest possible concentration of 1.0 μg/L for 40 minutes was considered to have a minimal adverse effect on the respiratory tract. The no observed adverse effect-level (NOAEL) is below this exposure level.