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EC number: 234-845-3 | CAS number: 12036-32-7
- Life Cycle description
- Uses advised against
- Endpoint summary
- Appearance / physical state / colour
- Melting point / freezing point
- Boiling point
- Density
- Particle size distribution (Granulometry)
- Vapour pressure
- Partition coefficient
- Water solubility
- Solubility in organic solvents / fat solubility
- Surface tension
- Flash point
- Auto flammability
- Flammability
- Explosiveness
- Oxidising properties
- Oxidation reduction potential
- Stability in organic solvents and identity of relevant degradation products
- Storage stability and reactivity towards container material
- Stability: thermal, sunlight, metals
- pH
- Dissociation constant
- Viscosity
- Additional physico-chemical information
- Additional physico-chemical properties of nanomaterials
- Nanomaterial agglomeration / aggregation
- Nanomaterial crystalline phase
- Nanomaterial crystallite and grain size
- Nanomaterial aspect ratio / shape
- Nanomaterial specific surface area
- Nanomaterial Zeta potential
- Nanomaterial surface chemistry
- Nanomaterial dustiness
- Nanomaterial porosity
- Nanomaterial pour density
- Nanomaterial photocatalytic activity
- Nanomaterial radical formation potential
- Nanomaterial catalytic activity
- Endpoint summary
- Stability
- Biodegradation
- Bioaccumulation
- Transport and distribution
- Environmental data
- Additional information on environmental fate and behaviour
- Ecotoxicological Summary
- Aquatic toxicity
- Endpoint summary
- Short-term toxicity to fish
- Long-term toxicity to fish
- Short-term toxicity to aquatic invertebrates
- Long-term toxicity to aquatic invertebrates
- Toxicity to aquatic algae and cyanobacteria
- Toxicity to aquatic plants other than algae
- Toxicity to microorganisms
- Endocrine disrupter testing in aquatic vertebrates – in vivo
- Toxicity to other aquatic organisms
- Sediment toxicity
- Terrestrial toxicity
- Biological effects monitoring
- Biotransformation and kinetics
- Additional ecotoxological information
- Toxicological Summary
- Toxicokinetics, metabolism and distribution
- Acute Toxicity
- Irritation / corrosion
- Sensitisation
- Repeated dose toxicity
- Genetic toxicity
- Carcinogenicity
- Toxicity to reproduction
- Specific investigations
- Exposure related observations in humans
- Toxic effects on livestock and pets
- Additional toxicological data
Acute Toxicity: inhalation
Administrative data
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- experimental study
- Adequacy of study:
- key study
- Study period:
- 09 July 2012 to 21 September 2012
- Reliability:
- 1 (reliable without restriction)
- Rationale for reliability incl. deficiencies:
- guideline study
- Justification for type of information:
- Read-across performed with structurally similar substance.
Cross-reference
- Reason / purpose for cross-reference:
- other: read-across target
Reference
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- supporting study
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: Study conducted on read-across material
- Justification for type of information:
- Read-across performed with structurally similar substance.
- Reason / purpose for cross-reference:
- read-across source
- Key result
- Sex:
- male/female
- Dose descriptor:
- LC50
- Effect level:
- > 5.21 mg/L air (analytical)
- Based on:
- test mat.
- Exp. duration:
- 4 h
Data source
Reference
- Reference Type:
- study report
- Title:
- Unnamed
- Year:
- 2 012
- Report date:
- 2012
Materials and methods
Test guideline
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)
- Deviations:
- yes
- Remarks:
- see below
- Principles of method if other than guideline:
- The mean mass median aerodynamic diameter (MMAD), which was 4.90, is outside the range given in test guidelines (1-4 µm). This deviation is considered to be due to the physical characteristics of the test material and is not considered to have affected the validity of the study.
- GLP compliance:
- yes (incl. QA statement)
- Test type:
- acute toxic class method
- Limit test:
- yes
Test material
- Reference substance name:
- Praseodymium(III,IV) oxide
- EC Number:
- 234-857-9
- EC Name:
- Praseodymium(III,IV) oxide
- Cas Number:
- 12037-29-5
- Molecular formula:
- O11Pr6
- IUPAC Name:
- praseodymium(III,IV) oxide
- Test material form:
- solid: particulate/powder
- Details on test material:
- Appearance: Brown powder
Storage conditions: Room temperature, in the dark
Constituent 1
Test animals
- Species:
- rat
- Strain:
- Wistar
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Strain: RccHan:WIST
- Age at study initiation: approximately 8 to 12 weeks
- Weight at study initiation: 200 to 350 g
- Fasting period before study: no
- Housing: The animals were housed in groups of up to three by sex in solid-floor polypropylene cages with stainless steel lids, furnished with softwood flakes and provided with environmental enrichment items: wooden chew blocks and cardboard “fun tunnels”.
- Diet (e.g. ad libitum): With the exception of the exposure period, free access to food was allowed; Harlan 2014C Rodent Diet, Harlan Laboratories UK Ltd., Oxon, UK.
- Water (e.g. ad libitum): ad libitum with the exception of the exposure period.
- Acclimation period: at least 5 days
- Source: Harlan Laboratories UK Ltd., Oxon, UK.
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 - 25 °C
- Humidity (%): 30 - 70 %
- Air changes (per hr): at least 15 per hour
- Photoperiod (hrs dark / hrs light): the lighting was controlled to give twelve hours continuous light and twelve hours darkness.
Administration / exposure
- Route of administration:
- inhalation: dust
- Type of inhalation exposure:
- nose only
- Vehicle:
- clean air
- Details on inhalation exposure:
- ATMOSPHERE GENERATION
A dust atmosphere was produced from the test material using an SAG 410 Solid Aerosol Generator located adjacent to the exposure chamber. The SAG 410 was connected to a metered compressed air supply.
A particle separator was introduced before the aerosol entered the exposure chamber during the sighting study in order to remove large particles and thereby increase the inhalable portion of the generated aerosol. This could not be utilised during the main study exposure as the target concentration could not be achieved with the particle separator attached to the generation equipment. The test material was ground in a Llytron mini grinder prior to use in the main study.
Compressed air was supplied by means of an oil free compressor and passed through a water trap and respiratory quality filters before it was introduced to the SAG 410.
The cylindrical exposure chamber had a volume of approximately 30 litres (dimensions: 28 cm diameter x 50 cm high). The concentration within the chamber was controlled by adjusting the test material feed rate from the SAG 410. The extract from the exposure chamber passed through a ‘scrubber’ trap and was connected with a high efficiency filter to a metered exhaust system. The chamber was maintained under negative pressure.
Prior to the start of the study, test material atmospheres were generated within the exposure chamber. During this characterisation period test material input rates and the generation system were varied in order to achieve the required atmospheric conditions.
EXPOSURE PROCEDURE
Prior to the day of exposure each rat was acclimatised (for approximately 2 hours) to a tapered polycarbonate restraining tube. During the day of exposure, each rat was individually held in a tapered, polycarbonate restraining tube fitted onto a single tier of the exposure chamber and sealed by means of a rubber ‘O’ ring.
A target concentration of 5.0 mg/L was used for the exposure. The mean achieved concentration was 104 % of target.
EXPOSURE CHAMBER TEMPERATURE AND RELATIVE HUMIDITY
The temperature and relative humidity inside the exposure chamber were measured by an electronic thermometer/humidity meter located in a vacant port in the animals’ breathing zone of the chamber and recorded every thirty minutes.
EXPOSURE CHAMBER OXYGEN CONCENTRATION
Oxygen levels within the exposure chamber were measured by an electronic oxygen analyser located in a port in the animals' breathing zone. The test atmosphere was generated to contain at least 19 % oxygen.
The MMAD was 4.90 µm, resulting in an inhalable fraction (% <4 µm) of 41.1. The geometric standard deviation was 2.50.
EXPOSURE CHAMBER ATMOSPHERE CONCENTRATION
The actual chamber concentration was measured at regular intervals during the exposure period. The gravimetric method used glass fibre filters placed in a filter holder. The holder was temporarily sealed in a vacant port in the exposure chamber in the animals’ breathing zone and a suitable, known volume of exposure chamber air was drawn through the filter using a vacuum pump.
Each filter was weighed before and after sampling in order to calculate the weight of collected test material. The difference in the two weights, divided by the volume of atmosphere sampled, gave the actual chamber concentration.
The nominal chamber concentration was calculated by dividing the mass of test material used by the total volume of air passed through the chamber.
The nominal concentration is 889 % of the actual mean achieved atmosphere concentration and shows that keeping the aerosol airborne was difficult.
PARTICLE SIZE DISTRIBUTION
The particle size of the generated atmosphere inside the exposure chamber was determined three times during the exposure period using a Marple Personal Cascade Impactor. This device consisted of six impactor stages (9.8, 6.0, 3.5, 1.6, 0.93 and 0.52 µm cut points) with stainless steel collection substrates and a back up glass fibre filter, housed in an aluminium sampler. The sampler was temporarily sealed in a sampling port in the animals’ breathing zone and a suitable, known volume of exposure chamber air was drawn through it using a vacuum pump.
The collection substrates and backup filter were weighed before and after sampling and the weight of the test material, collected at each stage, calculated by the difference.
The mean amount 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 9.8, 6.0, 3.5, 1.6, 0.93 and 0.52 µm was calculated.
The resulting values were converted to probits and plotted against Log10 cut-point size. From this plot, the Mass Median Aerodynamic Diameter (MMAD) was determined (as the 50 % point) and the geometric standard deviation was calculated. In addition the proportion (%) of aerosol less than 4 µm (considered to be the inhalable fraction) was determined. - Analytical verification of test atmosphere concentrations:
- yes
- Remarks:
- The test atmosphere was sampled seventeen times during the exposure period and the actual concentration of the test material calculated.
- Duration of exposure:
- 4 h
- Concentrations:
- 5.21 mg/L
- No. of animals per sex per dose:
- 3 animals per sex per dose
- Control animals:
- no
- Details on study design:
- - Duration of observation period following administration: all animals were observed for clinical signs at hourly intervals during exposure, immediately on removal from the restraining tubes at the end of exposure, one hour after termination of exposure and subsequently once daily for up to 14 days. Any evidence of overt toxicity was recorded at each observation.
- Frequency of weighing: Individual bodyweights were recorded on arrival, prior to treatment on the day of exposure and on Days 1, 3, 7 and 14.
- Necropsy of survivors performed: yes. At the end of the 14 day observation period the animals were killed by intravenous overdose of sodium pentobarbitone. All animals were subjected to a full external and internal examination, and any macroscopic abnormalities were recorded. The respiratory tract was subjected to a detailed macroscopic examination for signs of irritancy or local toxicity.
Results and discussion
- Preliminary study:
- SIGHTING EXPOSURE
During characterisation, a group of two rats (one male, one female) were exposed to an atmosphere of the test material at a mean achieved atmosphere concentration of 2.26 mg/L for approximately four hours. Increased respiratory rate was the only significant observation noted in both animals during exposure, on removal from the chamber and one hour post-exposure, red/brown staining around the snout was also noted in both animals on removal. One day post-exposure, both animals exhibited increased respiratory rate and hunched posture only. Both animals recovered quickly to appear normal on Day 3 or Day 4 post-exposure.
Effect levels
- Key result
- Sex:
- male/female
- Dose descriptor:
- LC50
- Effect level:
- > 5.21 mg/L air (analytical)
- Based on:
- test mat.
- Exp. duration:
- 4 h
- Mortality:
- There was no mortality during the study.
- Clinical signs:
- other: In addition to the observations considered to be due to the restraint procedure (such as hunched posture, pilo-erection, wet fur and fur staining due to the test material), increased respiratory rate was noted in all animals during exposure, on removal fr
- Body weight:
- All animals exhibited bodyweight losses or showed no bodyweight gain on the first day post-exposure. All animals exhibited bodyweight gains during the remainder of the observation period, with the exception of one female animal which showed no bodyweight gain from Days 1 to 3 post-exposure.
- Gross pathology:
- Four animals (all males and one female) exhibited dark patches on the lungs at necropsy.
Any other information on results incl. tables
Table 1: Exposure Chamber Atmosphere Concentrations
Duration of Exposure (minutes) |
Net Weight of Sample (mg) |
Volume of Air Sampled (L) |
Chamber Flow Rate (L/min) |
Atmosphere Concentration (mg/L) |
5 |
9.81 |
2 |
60 |
4.91 |
15 |
10.56 |
2 |
60 |
5.28 |
29 |
10.72 |
2 |
60 |
5.36 |
45 |
10.17 |
2 |
60 |
5.09 |
60 |
10.05 |
2 |
60 |
5.03 |
75 |
10.74 |
2 |
60 |
5.37 |
90 |
10.31 |
2 |
60 |
5.16 |
105 |
11.94 |
2 |
60 |
5.97 |
120 |
10.18 |
2 |
60 |
5.09 |
135 |
10.46 |
2 |
60 |
5.23 |
150 |
10.32 |
2 |
60 |
5.16 |
165 |
10.76 |
2 |
60 |
5.38 |
181 |
9.80 |
2 |
60 |
4.90 |
195 |
10.09 |
2 |
60 |
5.05 |
210 |
10.66 |
2 |
60 |
5.33 |
225 |
10.67 |
2 |
60 |
5.34 |
235 |
9.84 |
2 |
60 |
4.92 |
Mean achieved atmosphere concentration: 5.21 mg/L (standard deviation 0.26)
Nominal Concentration
- Test material used: 714 g
- Air flow: 60 L/min
- Total generation time: 257 minutes*
- Nominal concentration: 46.3 mg/L
* Test atmospheres were generated for a total of 17 minutes prior to animal insertion to ensure that the test material concentration was being achieved.
Table 2: Particle Size Distribution - Cascade Impactor Data
Impactor Stage Number |
Cut Point (µm) |
Amount Collected (mg) Per Sample Number |
Mean Amount Collected (mg) |
||
1 |
2 |
3 |
|||
3 |
9.8 |
0.69 |
0.82 |
0.54 |
0.68 |
4 |
6.0 |
0.67 |
0.84 |
0.55 |
0.69 |
5 |
3.5 |
0.76 |
0.93 |
0.54 |
0.74 |
6 |
1.6 |
0.53 |
0.67 |
0.57 |
0.59 |
7 |
0.93 |
0.34 |
0.43 |
0.29 |
0.35 |
8 |
0.52 |
0.02 |
0.09 |
0.12 |
0.08 |
Back-up filter |
<0.52 |
0.00 |
0.05 |
0.02 |
0.02 |
Total mean amount of test material collected: 3.15 mg
Table 3: Particle Size Distribution - Calculation
Cut Point (µm) |
Log10 Cut Point |
Mean Cumulative Amount Less Than Cut Point |
||
(mg) |
(%) |
Probit |
||
9.8 |
0.991 |
2.47 |
78.4 |
5.79 |
6.0 |
0.778 |
1.78 |
56.5 |
5.16 |
3.5 |
0.544 |
1.04 |
33.0 |
4.56 |
1.6 |
0.204 |
0.45 |
14.3 |
3.93 |
0.93 |
-0.032 |
0.10 |
3.18 |
3.14 |
0.52 |
-0.284 |
0.02 |
0.635 |
2.51 |
MMAD: 4.90 µm
Geometric standard deviation: 2.50
Predicted amount <4 µm: 41.1 %
Table 4: Individual Bodyweights
Animal Number and Sex |
Bodyweight (g) on Day: |
Increment (g) During Days: |
|||||||||
-9 |
0 |
1 |
3 |
7 |
14 |
-9 to 0 |
0 to 1 |
1 to 3 |
3 to 7 |
7 to 14 |
|
1 Male |
241 |
288 |
280 |
297 |
312 |
319 |
47 |
-8 |
17 |
15 |
7 |
2 Male |
229 |
263 |
254 |
264 |
270 |
290 |
34 |
-9 |
10 |
6 |
20 |
3 Male |
236 |
271 |
266 |
271 |
283 |
294 |
35 |
-5 |
5 |
12 |
11 |
4 Female |
191 |
226 |
219 |
229 |
236 |
245 |
35 |
-7 |
10 |
7 |
9 |
5 Female |
199 |
228 |
228 |
234 |
238 |
250 |
29 |
0 |
6 |
4 |
12 |
6 Female |
187 |
218 |
216 |
216 |
221 |
224 |
31 |
-2 |
0 |
5 |
3 |
Applicant's summary and conclusion
- Interpretation of results:
- other: Not classified in accordance with EU criteria
- Conclusions:
- The 4 hour LC50 was determined to be > 5.21 mg/L, therefore the test material requires no classification under the conditions of this study in accordance with EU criteria.
- Executive summary:
An acute inhalation study was conducted to assess the toxicity potential of the test material in accordance with the standardised guideline OECD 436.
Male and female RccHan:WIST strain rats (3 per sex) were exposed (nose only) for 4 hours to a dust atmosphere containing the test material at a mean concentration of 5.21 mg/L, with a MMAD of 4.90 µm.
Following exposure, the animals were observed for 14 days for signs of mortality and toxicity. At the end of the observation period, all animals were subjected to necropsy.
No deaths occurred throughout the study and the 4 hour LC50 was therefore determined to be > 5.21 mg/L. The test material requires no classification under the conditions of this study in accordance with EU criteria.
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