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EC number: 235-118-3 | CAS number: 12070-06-3
- 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
Endpoint summary
Administrative data
Description of key information
In an acute oral toxicity according to OECD 423 no mortality was observed in rats at concentrations of 2000 mg tantalum/kg bw.
In an acute inhalation toxicity study according to OECD 403 conducted with tantalum and tantalum pentoxide no mortality occurred in rats at the highest practicable concentrations (5.18 mg/L and 3.89 mg/L tantalum and tantalum pentoxide, respectively).
Tantalum and tantalum pentoxide data are used in read-across approach in the assessment of the acute toxicity of tantalum carbide.
Key value for chemical safety assessment
Acute toxicity: via oral route
Link to relevant study records
- Endpoint:
- acute toxicity: oral
- Type of information:
- migrated information: read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Study period:
- 2000-09-23 to 2000-12-18
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: GLP guideline study. Tantalum used as read-across partner to Tantalum carbide.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 423 (Acute Oral toxicity - Acute Toxic Class Method)
- Deviations:
- no
- Qualifier:
- according to guideline
- Guideline:
- EU Method B.1 (Acute Toxicity (Oral))
- Deviations:
- no
- GLP compliance:
- yes
- Test type:
- acute toxic class method
- Limit test:
- yes
- Species:
- rat
- Strain:
- Sprague-Dawley
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Harlan U.K. Ltd., Bicester, Oxon, England
- Age at study initiation: 5 - 7 weeks
- Weight at study initiation: 92 - 115 g
- Fasting period before study: overnight prior to and approximately 4 hours following dosing
- Housing: in groups of three by sex in metal cages with mesh floors
- Diet: ad libitum
- Water: ad libitum
- Acclimation period: 5 days (min.)
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3
- Humidity (%): 30 - 70
- Photoperiod (hrs dark / hrs light): 12 / 12 - Route of administration:
- oral: gavage
- Vehicle:
- other: 1 % w/v aqueous methylcellulose
- Details on oral exposure:
- VEHICLE - 1 % w/v aqueous methylcellulose
DOSE VOLUME APPLIED: 10 mL/kg bw
TEST MATERIAL PREPARATION: the test material was formulated at a concentration of 20 % w/v in 1 % w/v aqueous methylcellulose and administered at a volume of 10 mL/kg bw. The test material was prepared on the day of dosing.
The appropriate dose volume of the test material was administered to each rat by oral gavage using a plastic syringe and catheter (8 ch). The day of dosing was designated day 1. - Doses:
- 2000 mg/kg bw
- No. of animals per sex per dose:
- 3
- Control animals:
- no
- Details on study design:
- - Treatment procedure: a group of three fasted female rats received the limit dose. As results at this dosage indicated the acute lethal oral dose to be greater than 2000 mg/kg bodyweight, in compliance with the study guidelines, a group of three fasted males was dosed at 2000 mg/kg to confirm the results and complete the study.
- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Mortality was checked at least twice daily while animals were observed for clinical signs soon after dosing and at frequent intervals for the remainder of day 1. On subsequent days, animals were observed once in the morning and again at the end of the experimental day. The nature and severity of the clinical signs and time were recorded at each observation. The bodyweight of each rat was recorded on days 1 (prior to dosing), 8 and 15. Individual weekly bodyweight changes and group mean bodyweights were calculated.
- Necropsy of survivors performed: yes - all animals were killed on day 15 by carbon dioxide asphyxiation and subjected to a macroscopic examination which consisted of opening the cranial, thoracic and abdominal cavities. The macroscopic appearance of all examined organs was recorded. - Statistics:
- N.A.
- Sex:
- male/female
- Dose descriptor:
- LD50
- Effect level:
- > 2 000 mg/kg bw
- Based on:
- test mat.
- Mortality:
- There were no deaths during the study.
- Clinical signs:
- other: Clinical signs of reaction to treatment were confined to piloerection and hunched posture, seen in all rats, with abnormal gait observed in all females. Recovery of rats, as judged by external appearance and behaviour, was complete by either day 2 (female
- Gross pathology:
- No abnormalities were revealed at the macroscopic examination at study termination on day 15.
- Other findings:
- N.A.
- Interpretation of results:
- practically nontoxic
- Remarks:
- Migrated information Criteria used for interpretation of results: EU
- Conclusions:
- In conclusion, in an acute oral toxicity study (OECD 423), the LD50 value in rats after oral Tantalum treatment was greater than 2000 mg/kg body weight.
- Executive summary:
In an acute oral toxicity study (OECD 423), groups of fasted Sprague Dawley rats (3/sex) were given a single dose of Tantalum (99.9 %) in 1% w/v aqueous methylcellulose at a dose of 2000 mg/kg bw and were observed for 14 days. There were only mild signs of toxicity oberserved and a full recovery of rats was completed by either day 2 (females) or day 3 (males). No mortality occurred. Based on the results from this study, the LD50 in rats after Tantalum treatment is considered to be greater than 2000 mg/kg bw.
This information is used in a read-across approach for the assessment of tantalum carbide.
Reference
Table 1: Signs of Reaction to Treatment
Clinical signs | No of rats in groups of 3 showing signs | |
Male | Female | |
Piloerection | 3 | 3 |
Hunched posture | 3 | 3 |
Abnormal gait | 0 | 3 |
Table 2: Individual Bodyweights and Bodyweight Gains
Dose (mg/kg) | Sex | Animal No. | Bodyweight (g) on day | Bodyweight gains (g) on day | |||
1* | 8 | 15 | 8 | 15 | |||
2000 | Male | 4 | 109 | 185 | 237 | 76 | 52 |
5 | 100 | 164 | 213 | 64 | 49 | ||
6 | 115 | 184 | 237 | 69 | 53 | ||
Mean | 108 | 178 | 229 | ||||
Female | 1 | 98 | 142 | 166 | 44 | 24 | |
2 | 92 | 134 | 157 | 42 | 23 | ||
3 | 98 | 137 | 160 | 39 | 23 | ||
Mean | 96 | 138 | 161 |
*Prior to dosing
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Quality of whole database:
- Ta data are used in a read-cross approach in the assessment of TaC.
Acute toxicity: via inhalation route
Link to relevant study records
- Endpoint:
- acute toxicity: inhalation
- Type of information:
- migrated information: read-across from supporting substance (structural analogue or surrogate)
- Adequacy of study:
- key study
- Study period:
- 2000-09-25 to 2001-03-20
- Reliability:
- 2 (reliable with restrictions)
- Rationale for reliability incl. deficiencies:
- other: GLP guideline study. Tantalum used as read-across partner to Tantalum carbide.
- Qualifier:
- according to guideline
- Guideline:
- OECD Guideline 403 (Acute Inhalation Toxicity)
- Deviations:
- yes
- Remarks:
- ; see text box below
- Qualifier:
- according to guideline
- Guideline:
- EPA OPPTS 870.1300 (Acute inhalation toxicity)
- Deviations:
- yes
- Remarks:
- ; see text box below
- Principles of method if other than guideline:
- The mass median aerodynamic diameter (MMAD) of the test aerosol was 4.6 µm. This MMAD is slightly in excess of the guideline maximum of 4.0 µm. However it is considered that the value obtained was the minimum practical at the concentration achieved given the nature of the test material.
- GLP compliance:
- yes
- Test type:
- standard acute method
- Limit test:
- yes
- Species:
- rat
- Strain:
- Sprague-Dawley
- Sex:
- male/female
- Details on test animals or test system and environmental conditions:
- TEST ANIMALS
- Source: Charles River UK Limited, Margate, England
- Age at study initiation: 7 and 8 weeks (males and females respectively)
- Housing: by sex, in groups of 5 in holding cages made of stainless steel sheet and wire mesh suspended on a movable rack
- Diet: ad libitum
- Water: tap water ad libitum
- Acclimation period: 6 days
ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19.5 - 20.5
- Humidity (%): 39 - 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:
- air
- Details on inhalation exposure:
- GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: a Wright Dust Feed mechanism was used to produce and maintain atmospheres containing a particulate aerosol by suspending material scraped from the surface of a compressed powder in a stream of dry air. The concentration of particulate aerosol was altered by changing the rate at which the scraper blade is advanced into the compressed powder held in the test material canister. The Wright Dust Feed was mounted on a glass cylinder attached to the top of the exposure chamber. The conditioned test atmosphere entered through a port at the top centre of the chamber and passed out through a port at the base section below the level of the rats.
- Exposure chamber volume: 30 L
- Method of holding animals in test chamber: snout-only exposure chambers (animals held in moulded polycarbonate restraining tubes and held in a forward position by an adjustable foamed plastic stopper, which also provided a seal for the tube)
- Source and rate of air: clean, dry air was passed through an electronic neutraliser, connected to a generator and the supply pressure adjusted to give a flow rate of 16 litre/minute. An in-line flow meter was used to monitor the generator air supply throughout the exposure. The exhaust airflow was calibrated and adjusted to produce a slightly negative pressure.
- Method of particle size determination: particle size measured with a Marple cascade impactor. The volume of air sampled was measured using a wet-type gas meter. The amount of material collected on the stages of the sampler was determined gravimetrically. The particle size distribution of the test atmosphere was then assessed using linear regression analysis.
- Treatment of exhausted air: the exposure system was positioned inside a large cabinet equipped with an extract fan exhausting to atmosphere through an absolute filter.
- Temperature and humidity in air chamber: 20.0 - 20.1 °C, 42 - 58 % (mean values)
TEST ATMOSPHERE
- Brief description of analytical method used: five samples of air were removed from the test chamber following equilibration and hourly thereafter. Each air sample was withdrawn at a rate of 2 L/min through a pre-weighed glass fibre filter. The volume of air sampled was measured using a wet-type gas meter. The filters were reweighed following sampling for gravimetric analysis of the test aerosol.
TEST ATMOSPHERE
- MMAD (Mass median aerodynamic diameter): 4.6 µm (approximately 67 % of the aerosol generated consisted of particulate of size < 7 µm) - Analytical verification of test atmosphere concentrations:
- yes
- Duration of exposure:
- 4 h
- Concentrations:
- The nominal concentration was 92.2 mg/L. The mean chamber concentration was 5.6 % of the nominal concentration that reflects losses of the test material due to impaction, deposition and cohesion due to static within the exposure system. The mean chamber concentration of total particulate was 5.18 mg/L and was in good agreement with target (5 mg/L).
- No. of animals per sex per dose:
- 5
- Control animals:
- yes
- Details on study design:
- - Duration of observation period following administration: 14 days.
- Environmental conditions in the exposure chamber: air temperature was measured using an alcohol-in-glass thermometer and relative humidity was measured using a Casella type T6900 relative humidity meter. The temperature and relative humidity were recorded at the start of exposure and then at 30 minute intervals during the 4 hour exposure.
- Frequency of observations and weighing: throughout the study, all cages were checked at least twice daily for dead or moribund animals. Rats were observed intermittently for signs of reaction to the test material during exposure and at least twice daily throughout the observation period. Clinical signs were recorded at the end of the chamber equilibration period, at 0.25, 0.5 and 1.0 hours then hourly during the exposure. Clinical signs were recorded immediately following exposure and then at 1.0 and 2.0 hours post-exposure. During the observation period, clinical signs were recorded twice daily. Bodyweights were recorded twice during the week prior to exposure (day 0) and then weekly during the observation period and on the day of death.
- Necropsy of survivors performed: yes.
- Other examinations performed: at the end of the 14-day observation period, the rats were killed by intraperitoneal injection of pentobarbitone sodium followed by exsanguinations from the brachial blood vessels and subjected to a detailed macroscopic examination. The lungs (including the larynx and trachea) were removed, dissected clear of surrounding tissue, weighed and the weights recorded. - Sex:
- male/female
- Dose descriptor:
- LC50
- Effect level:
- > 5.18 mg/L air
- Based on:
- test mat.
- Exp. duration:
- 4 h
- Mortality:
- There were no unscheduled deaths.
- Clinical signs:
- other: DURING EXPOSURE: - Exaggerated breathing was observed in a proportion of test rats from 15 minutes and in all test rats from 30 minutes into exposure. Grey staining of the fur was noted for all test rats from 3 hours into exposure. Soiling of the fur wit
- Body weight:
- There were no treatment-related effects.
- Gross pathology:
- There were no treatment-related effects at necropsy.
Incidental effects noted included: small dark foci noted on the lungs of two male test rats and a male control rat. Hair loss from head was noted for a male test rat. - Other findings:
- Lung weight: there were no treatment-related effects.
- Interpretation of results:
- practically nontoxic
- Remarks:
- Migrated information Criteria used for interpretation of results: EU
- Conclusions:
- In conclusions, in acute inhalation study in rats the LC50 after nose-only exposure to Tantalum was estimated to be greater than 5.18 mg/L.
- Executive summary:
In an acute inhalation toxicity study (OECD 403), groups of young adult Sprague Dawley rats (5/sex) were exposed nose-only to Tantalum (99.9%) for 4 hours at a concentration of 5.18 mg/L. Animals then were observed for 14 days. A further group, acting as a concurrent common control was exposed to clean air only. No unscheduled deaths occurred. Clinical signs during the exposure period were limited to exaggerated breathing in test rats 15 to 30 minutes into exposure and grey staining on the fur 3 hours into exposure. During the observation period, clinical signs were limited to exaggerated breathing in all test rats immediately post exposure, persisting to day 4 of the observation period. A black/grey substance on the fur of the snout and jaws was evident on all test animals, persisting to day 2 of the observation period and hair loss from head of a single male test rat on day 14 of the observation period. All animals gained weight during the study. There were no macroscopic abnormalities at examination post mortem. Based on the results, LC50 was estimated to be greater than 5.18 mg/L for both male and female rats.
This information is used in a read-across approach for the assessment of tantalum carbide.
Reference
Table 1: Chamber Concentration of Test Material
Sample | Time taken (h:min) | Gravimetric conc. (mg/L) | Nominal conc. (mg/L) |
1 | 0:10 | 4.95 | |
2 | 1:00 | 5.00 | |
3 | 2:00 | 5.48 | |
4 | 2:58 | 5.04 | |
5 | 3:54 | 5.41 | |
Mean | 5.18 | 92.2 | |
SD | 0.249 |
Table 2: Particle Size Distribution of Test Material
Sample | Time taken (h:min) | Stage | Cut-off size (µm) | Amount collected (mg) |
PSD 1 | 1:31 | 1 | 21.30 | 0.06 |
2 | 14.80 | 0.07 | ||
3 | 9.80 | 0.35 | ||
4 | 6.00 | 0.63 | ||
5 | 3.50 | 0.34 | ||
6 | 1.55 | 0.26 | ||
7 | 0.93 | 0.01 | ||
8 | 0.52 | 0.00 | ||
Filter | 0.00 | 0.08 | ||
Total | 1.80 | |||
PSD 2 | 3:31 | 1 | 21.30 | 0.00 |
2 | 14.80 | 0.09 | ||
3 | 9.80 | 0.39 | ||
4 | 6.00 | 0.77 | ||
5 | 3.50 | 0.40 | ||
6 | 1.55 | 0.29 | ||
7 | 0.93 | 0.06 | ||
8 | 0.52 | 0.03 | ||
Filter | 0.00 | 0.08 | ||
Total | 2.11 |
Table 3: Calculations | |||
Cut-off size (µm) | % less than size (cumulative) | ||
PSD 1 | PSD 2 | Combined | |
21.30 | 96.60 | 100.00 | 98.50 |
14.80 | 92.70 | 95.70 | 94.40 |
9.80 | 73.30 | 77.20 | 75.50 |
6.00 | 38.30 | 40.70 | 39.70 |
3.50 | 19.40 | 21.70 | 20.80 |
1.55 | 5.00 | 8.00 | 6.70 |
0.93 | 4.40 | 5.20 | 4.90 |
0.52 | 4.40 | 3.80 | 4.10 |
MMAD (µm) | 5.10 | 4.00 | 4.60 |
geometric SD | 2.66 | 2.28 | 2.53 |
% respirable (< 7 µm) | 62.00 | 75.00 | 67.00 |
SD= standard deviation
Table 4: Individual and Group Mean Bodyweights
Group | Rat | Day of observation | ||||||
-7 | -4 | -2 | -1 | 0 | 7 | 14 | ||
1 M (Control) | 101 | 215 | 246 | 268 | 278 | 331 | 377 | |
102 | 221 | 253 | 277 | 284 | 331 | 368 | ||
103 | 223 | 245 | 274 | 280 | 332 | 349 | ||
104 | 235 | 265 | 288 | 298 | 350 | 386 | ||
105 | 228 | 265 | 292 | 295 | 359 | 404 | ||
Mean | 224 | 255 | 280 | 287 | 341 | 377 | ||
2 M (Test) | 81 | 219 | 239 | 258 | 306 | 352 | ||
82 | 220 | 239 | 257 | 297 | 332 | |||
83 | 228 | 243 | 261 | 299 | 335 | |||
84 | 228 | 249 | 263 | 300 | 343 | |||
85 | 218 | 235 | 253 | 300 | 343 | |||
Mean | 223 | 241 | 258 | 300 | 341 | |||
1 F (Control) | 106 | 204 | 223 | 234 | 237 | 256 | 265 | |
107 | 189 | 199 | 199 | 204 | 209 | 205 | ||
108 | 208 | 220 | 228 | 229 | 243 | 252 | ||
109 | 204 | 222 | 225 | 233 | 255 | 255 | ||
110 | 209 | 222 | 231 | 236 | 245 | 247 | ||
Mean | 203 | 217 | 223 | 228 | 242 | 245 | ||
2 F (Test) | 86 | 199 | 215 | 222 | 238 | 242 | ||
87 | 205 | 211 | 212 | 227 | 235 | |||
88 | 203 | 207 | 216 | 233 | 237 | |||
89 | 208 | 212 | 219 | 222 | 211 | |||
90 | 196 | 205 | 209 | 218 | 229 | |||
Mean | 202 | 210 | 216 | 228 | 231 |
Endpoint conclusion
- Endpoint conclusion:
- no adverse effect observed
- Quality of whole database:
- No deaths occured after 4h exposure of rats by Ta and Ta2O5, respectively. Test substance concentrations were higher in the study conducted with Ta (exposure concentration of test item itself as well as converted to concentration of TaC). Thus this study is considered to be the key study for the risk assessment of TaC (read-across approach).
Acute toxicity: via dermal route
Endpoint conclusion
- Endpoint conclusion:
- no study available
Additional information
Tantalum and tantalum pentoxide were used to assess in a read across approach the acute toxicity of tantalum carbide. Assuming that tantalum is the crucial component of tantalum carbide for the toxicity assessment, both tantalum and tantalum pentoxide serve the purpose of toxicity assessment as they are of higher solubility in water than tantalum carbide. Therefore the applied doses of tantalum by treatment with either tantalum of tantalum pentoxide fulfil the requirements of test dosages specified in OECD guidelines 404 and 405.
In an acute oral toxicity according to OECD 423 rats showed no mortality after treatment with tantalum at a dose of 2000 mg/kg bw. Thus the oral LD50 can be considered to be greater than 2000 mg/kg bw. In an acute inhalation toxicity study according to OECD 403 rats were exposed nose only to the source substances tantalum and tantalum pentoxide for 4 hours and were afterwards observed for 14 days. No mortality occurred at the highest concentration which was possible to generate. Thus, the LC 50 for tantalum is considered to be greater than 5.18 mg/L and the LC 50 after inhalation of tantalum pentoxide is considered to be greater than 3.89 mg/L.
For a detailed description of the read-across approach please refer to the read-across report.
Justification for selection of acute toxicity – oral endpoint
GLP guideline study according to OECD 423
Justification for selection of acute toxicity – inhalation endpoint
GLP guideline study according to OECD 403
Justification for classification or non-classification
The target substance tantalum carbide does not warrant classification for acute toxicity as no mortality occurred after treatment with the suitable read-across partner in acute toxicity studies according to OECD 423 and OECD 403.
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