Vanadium carbide

Endpoint summary

Description of key information

Vanadium carbide is not acutely toxic via the oral, dermal, or inhalation route.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

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:

2011-01-31 to 2011-03-03

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

adopted 2001-12-17

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2011-01-21

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

Crj: CD(SD)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd
- Age at study initiation: approximately eight to twelve weeks of age prior to dosing (Day 1)
- Weight at study initiation: 205 - 235 g (Day 1)
- Fasting period before study: overnight prior to and approximately four hours after dosing
- Housing: they were housed in groups of three rats of the same sex, in solid bottomed polycarbonate cages with a stainless steel mesh lid. Each cage contained a quantity of autoclaved wood flake bedding.
- Diet (ad libitum, for exception please refer to "Fasting period before study" above): standard rodent diet (Rat and Mouse No. 1 Maintenance Diet); This diet contained no added antibiotic or other chemotherapeutic or prophylactic agent.
- Water (ad libitum): potable water
- Acclimation period: at least 5 days before treatment

During the acclimatisation period, each cage of animals was provided with a soft white untreated chew block and a plastic shelter for environmental enrichment. The wood blocks were removed from the cage of animals for the same period as the food on the day prior to dosing.

ENVIRONMENTAL CONDITIONS
- Temperature: 19 to 23°C
- Relative humidity: 40 to 70%
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

corn oil

Details on oral exposure:

DOSAGE PREPARATION: the test substance was formulated at a concentration of 30 and 200 mg/mL in the vehicle and
administered at a volume of 10 mL/kg bodyweight. The test substance formulations were prepared on the day of dosing.
Formulations were mixed using a vortex mixer just before the dosing procedure.

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: as no previous toxicological information was available the initial dose level was 300 mg/kg.

Doses:

300 and 2000 mg/kg

No. of animals per sex per dose:

6 female animals

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: cages of rats were checked at least twice daily for any mortalities. 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 (with the exception of Day 15 - morning only). The nature and severity, where appropriate, of the clinical signs and the time were recorded at each observation. The body weight 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 humanely killed on Day 15 by carbon dioxide asphyxiation.
All animals were subject to a macroscopic examination which consisted of opening the cranial, thoracic and abdominal cavities. The macroscopic appearance of all examined organs was recorded.

Statistics:

not applicable

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: LD50 cut off value: 5000 mg/kg bw

Mortality:

There were no deaths during the study.

Clinical signs:

other: There were no clinical signs of reaction to treatment throughout the study.

Gross pathology:

No abnormalities were noted in any animal at the macroscopic examination at study termination on Day 15.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

LD50 (female rats) > 2000 mg/kg bw (LD50 cut off value: 5000 mg/kg bw)
According to the EC-Commission directive 67/548/EEC and its subsequent amendments, vanadium carbide nitrate is not classified as acute toxic via the oral route.
According to the EC-Regulation 1272/2008 and subsequent regulations, vanadium carbide nitrate is not classified as acute toxic via the oral route.

Reference 2

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:

2010-08-05 to 2010-08-31

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study reliable without restrictions

Qualifier:

according to guideline

Guideline:

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

Version / remarks:

, adopted 2001-12-17

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2009-11-12

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Crj: CD(SD)

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany
- Age at study initiation: Approx. 8 weeks
- Weight at study initiation: 163 - 191 g
- Fasting period before study: Feeding was discontinued approx. 16 hours before administration.
- Housing: Granulated textured wood (Granulat A2, J. Brandenburg, 49424 Goldenstedt, Germany) was used as bedding material for the cages. During the 14-day observation period the animals were kept in groups of 3 animals in MAKROLON cages (type III plus).
- Diet: Commercial diet, ssniff® R/M-H V1534 (ssniff Spezialdiäten GmbH, 59494 Soest, Germany)
- Water (ad libitum): Drinking water
- Acclimation period: At least 5 adaptation days

ENVIRONMENTAL CONDITIONS
- Temperature: 22°C ± 3°C (maximum range)
- Relative humidity: 55% ± 15% (maximum range)
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Route of administration:

oral: gavage

Vehicle:

other: hydroxypropylmethylcellulose

Details on oral exposure:

MAXIMUM DOSE VOLUME APPLIED: The administration volume was 10 mL/kg b.w.

DOSAGE PREPARATION: Vanadium (metal powder) was suspended to the appropriate concentration in 0.8% aqueous hydroxypropylmethylcellulose (Methocel; batch no. 09 D14-N28, Fagron GmbH & Co., 22885 Barsbüttel, Germany).
No further information on the oral exposure was stated.

Doses:

2000 mg/kg b.w.

No. of animals per sex per dose:

1 dose level group of 6 female animals

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations were performed before and immediately, 5, 15, 30 and 60 min, as well as 3, 6 and 24 hours after administration.
During the follow-up period of two weeks, changes of skin and fur, eyes and mucous membranes, respiratory and the circulatory, autonomic and central nervous system and somatomotor activity as well as behaviour pattern were observed at least once a day until all symptoms subsided, thereafter each working day. Attention was also paid to possible tremors, convulsions, salivation, diarrhoea, lethargy, sleep and coma.
Observations on mortality were made at least once daily to minimize loss of animals during the study. Individual body weights were recorded before administration of the test item and thereafter in weekly intervals up to the end of the study.
- Necropsy of survivors performed: Yes
All animals were sacrificed, dissected and inspected macroscopically. All gross pathological changes were recorded.
- Other examinations performed: Changes in weight were calculated and recorded.
No further information on the test material was stated.

Statistics:

Not applicable

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Mortality:

No mortality occurred.

Clinical signs:

other: A single oral administration of 2000 mg vanadium (metal powder)/kg b.w. to female rats did not reveal any signs of toxicity. No clinical signs were observed.

Gross pathology:

No pathological changes were observed at necropsy.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

LD50 (rats, females) >2000 mg/kg b.w.
According to the EC-Commission Directive 67/548/EEC and its subsequent amendments on the approximation of the laws, regulations and administrative provision relating to the classification, packaging and labelling of dangerous substances and the results obtained under the present test conditions vanadium (metal powder) is non-toxic if swallowed, hence, no labelling is required.
Also, according to the EC Regulation 1272/2008 and subsequent regulations, the test material is not classified for acute oral toxicity.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

Two GLP-studies are reliable without restrictions.

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:

2013-01-03 to 2013-02-13

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 436 (Acute Inhalation Toxicity: Acute Toxic Class Method)

Version / remarks:

adoped September 7, 2009

Deviations:

no

Qualifier:

according to guideline

Guideline:

other: OECD Series on Testing and Assessment No. 125, Document No. ENV/JM/MONO (2010) 16, June 01, 2010

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

signed 2009-11-12

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

other: Crl: CD(SD)

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories, Research Models and Services, Germany GmbH, Sandhofer Weg 7, 97633 Sulzfeld, Germany
- Age at study initiation: males: 8 weeks; females: 9 weeks
- Weight at study initiation: males: 259 - 267 g; females: 220 - 237 g
- Fasting period before study: feeding was discontinued approx. 16 hours before exposure; only tap water was then available ad libitum.
- Housing: granulated textured wood (Granulat A2, J. Brandenburg, 49424 Goldenstedt, Germany) was used as bedding material for the cages. During the 14-day observation period, the animals are kept by sex in groups of 3 animals in MAKROLON cages (type III plus).
- Diet (e.g. ad libitum): commercial diet, ssniff® R/M-H V1534 (ssniff Spezialdiäten GmbH, 59494 Soest, Germany)
- Water (ad libitum): drinking water
- Acclimation period: at least 5 adaptation days

The animals were randomised before use. They were acclimatised to the test apparatus for approx. 1 hour on 2 days prior to testing. The restraining tubes did not impose undue physical, thermal or immobilization stress on the animals.

ENVIRONMENTAL CONDITIONS
- Temperature: 22°C ± 3°C (maximum range)
- Relative humidity: 55% ± 15% (maximum range)
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: the study was carried out using a dynamic inhalation apparatus (RHEMA-LABORTECHNIK, 65719 Hofheim/Taunus, Germany) (air changes/h (≥ 12 times)) with a nose-only exposure of the animals according to KIMMERLE & TEPPER. The apparatus consists of a cylindrical exposure chamber (volume 40 L) which holds 10 animals in pyrex tubes at the edge of the chamber in a radial position.

- System of generating particulates/aerosols: the dust of the test material was generated with a rotating brush dust generator (RBG 1000, PALAS GmbH Partikel und Lasermesstechnik,76229 Karlsruhe, Germany).
The generator was fed with compressed air (5.0 bar) from a compressor (ALUP Kompressorenfabrik, 73257 Köngen, Germany) (air was taken from the surrounding atmosphere of the laboratory room and filtered using at in-line disposable gas-filter).
At the bottom of the exposure chamber, the air was sucked off at a lower flow rate than it was created by the dust generator in order to produce a homogenous distribution and a positive pressure in the exposure chamber (inflow 900 L/h, outflow 800 L/h).
A manometer and an air-flow meter (ROTA Yokogawa GmbH & Co. KG, 79664 Wehr/Baden, Germany) were used to control the constant supply of compressed air and the exhaust, respectively. Flow rates were checked hourly and the corrected if necessary.
The exhaust air was drawn through gas wash-bottles.

- Method of particle size determination: an analysis of the particle size distribution was carried out twice during the exposure period using a cascade impactor according to MAY (MAY, K. R. Aerosol impaction jets, J. Aerosol Sci. 6, 403 (1975), RESEARCH ENGINEERS Ltd., London N1 5RD, UK.).
The dust from the exposure chamber was drawn through the cascade impactor for 5 minutes at a constant flow rate of 5 L/min. The slides were removed from the impactor and weighed on an analytical balance (SARTORIUS, type 1601 004, precision 0.1 mg). Deltas of slides’ weight were determined.
The mass median aerodynamic diameter (MMAD) was estimated by means of non-linear regression analysis. The 32 μm particle size range and the filter (particle size range < 0.5 μm) were not included in the determination of the MMAD in order not to give undue weight to these values.
The Geometric Standard Deviation (GSD) of the MMAD was calculated from the quotient of the 84.1 % - and the 50 %- mass fractions, both obtained from the above mentioned non-linear regression analysis.
In addition, a sample of approx. 10 g test material was taken from the exposure chamber to determine the median physical particle size with a CILAS 715 by My-Tec, 91325 Adelsdorf, Germany. This determination was non-GLP.

- Temperature, humidity, pressure in air chamber, oxygen content and carbon dioxide concentration: the oxygen content in the inhalation chamber was 21%. It was determined at the beginning and at the end of the exposure with a DRÄGER Oxygen-analysis test set (DRÄGER Tube Oxygen 67 28 081). Carbon dioxide concentration did not exceed 1%.
Temperature (21.3 °C ± 0.1 °C (main study) or 20.9 °C ± 0.1 °C (satellite group)) and humidity (70.3 % ± 0.1 % (main study) or 63.3 % ± 0.1 % (satellite group)) were measured once every hour with a climate control monitor (testo 175-HZ data logger).

The whole exposure system was mounted in an inhalation facility to protect the laboratory staff from possible hazards.

Exposition started by locating the animals into the exposure chamber after equilibration of the chamber concentration for at least 15 minutes (t95 approximately 8 minutes).

Before initiating the study with the animals, a pre-test was carried out with the exposure system in order to verify that under the experimental settings chosen, the limit concentration of 5 mg/L air could be achieved by gravimetric analysis.

The tests with the main study animals and the recovery animals were conducted in the same inhalation chamber but on different days. Between the exposure times the chamber was cleaned carefully.

TEST ATMOSPHERE
- Brief description of analytical method used: the actual dust concentration in the inhalation chamber was measured gravimetrically with an air sample filter (Minisart SM 17598 0.45 μm) and pump (Vacuubrand, MZ 2C (Membrane Pump,Vacuubrand GmbH + Co. KG, 97877 Wertheim/Main, Germany)) controlled by a rotameter. Dust samples were taken once every hour during the exposure. For that purpose, a probe was placed close to the animals' noses and air was drawn through the air sample filter at a constant flow of air of 5 L/min for 1 minute. The filters were weighed before and after sampling (accuracy 0.1 mg).
Individual chamber concentration samples did not deviate from the mean chamber concentration by more than 1%.
- Samples taken from breathing zone: yes

TEST ATMOSPHERE
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.):
Main study: 2.526 µm (GSD: 3.09)
Satellite group: 2.476 µm (GSD: 3.16)
No smaller GSDs could be obtained with the test item supplied.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

see above ("Details on inhalation exposure")

Duration of exposure:

4 h

Concentrations:

Main study (limit test):
- actual concentration: 5.05 ± 0.03 mg/L air
- nominal concentration: 7.78 mg/L air
Satellite group:
- actual concentration: 5.06 ± 0.03 mg/L air
- nominal concentration: 7.78 mg/L air

No. of animals per sex per dose:

Main study (limit test):
3 males / 3 females
Satellite group:
3 males / 3 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 24 hours (satellite group) and 14 days (main study)

- Frequency of observations and weighing: during the exposure period the animals were observed frequently. Following exposure, observations were made at least twice on the day of exposure and at least once each day and recorded systematically. A careful clinical examination was made at least once each day thereafter for a period of 14 days. Observations on mortality were made at least once daily (in the morning starting on test day 2) to minimize loss of animals to the study, e.g. necropsy or refrigeration of those animals found dead and isolation or sacrifice of weak or moribund animals.
Cageside observations included, but were not limited to: changes in the skin and fur, eyes, mucous membranes, respiratory, circulatory, autonomic and central nervous system, as well as somatomotor activity and behaviour pattern.
Particular attention was directed to observation of tremor, convulsions, salivation, diarrhoea, lethargy, sleep and coma. The animals were also observed for possible indications of respiratory irritation such as dyspnoea, rhinitis etc.
Individual weights of animals were determined once during the acclimatisation period, before and after the exposure on test day 1, on test days 3, 8 and 15. Changes in weight were calculated and recorded when survival exceeded one day. At the end of the test, all animals were weighed and sacrificed.

- Necropsy of survivors performed: yes
Necropsy of all main study and satellite animals (3 + 3 males and 3 + 3 females) was carried out and all gross pathological changes were recorded:
- Satellite animals: necropsy at 24 hours after cessation of exposure, as this is likely to be the time at which any signs of respiratory irritation would have manifested;
- Main study animals: necropsy at the end of the 14-day observation period, also to assess whether any respiratory tract irritation persists or abates.

- Histopathology:
All main study and satellite animals were subjected to the same level of histopathological examination upon necropsy at the end of the respective observation period. During histopathology, attention was paid to alterations that might be indicative of respiratory irritation, such as hyperaemia, oedema, minimal inflammation, thickened mucous layer.
The following organs of all animals were fixed in 10 % (nose, i.e. head without brain, eyes and lower jaw) or 7 % (other organs) buffered formalin for histopathological examination:
- Nasal cavity, nasopharynx and paranasal sinus:
The tip and level 1 of the nose were taken from a cut just anterior to the incisor teeth. With tip removed, level 2 was taken approximately 2 mm posterior to free tip of the incisor teeth. Level 3 was cut through the incisive papilla. Level 4 was cut through the middle of the second palatal ridge, which is located just anterior to the molar teeth. Level 5 was cut through the middle of the molar teeth. All sections were embedded face down to yield a section from the anterior section, except the nose tip was embedded posterior surface down.
- Larynx
- Trachea
- Lungs (five levels)
Paraffin sections were prepared of all above mentioned organs and stained with haematoxylin-eosin.

Statistics:

Since no animal died prematurely, the calculation of an LC50 was not required.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.05 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

No animal died prematurely.

Clinical signs:

other: Under the present test conditions, a 4-hour inhalation exposure to Vanadium carbide at a concentration of 5.05 mg/L air revealed slight ataxia on test day 1 immediately after the end of exposure until 30 minutes post exposure, slight dyspnoea (reduced fre

Body weight:

No influence on body weight gain was observed.

Gross pathology:

Macroscopic changes in the nasal cavity and lungs: marbled lungs were observed in all animals of the main study (14-day sacrifice) and in all satellite animals (24-hour sacrifice). Oedematous lungs were observed in 2 of 3 male or female animals of the main study, each, and 1 of 3 male or female satellite animals, each. Lungs reduced in size were observed in 1 male and 1 female main study animals and 1 female satellite animal. A greyish discoloured lung was observed in 1 male satellite animal.

Other findings:

- HISTOPATHOLOGY:

Microscopic changes in the nasal cavity and lungs:
1. Test item-related histopathological changes:
The histomorphological examination of the trachea, larynx, lungs and the nose of male and female rats after inhalation of Vanadium carbide did not reveal any morphological changes, considered to be related to the inhalation of the test item, in the main study animals (14-day sacrifice) and in the satellite animals (24-hour sacrifice).

2. Non-test item-related histopathological changes:
Male and female animals of the main study (14-day sacrifice) and the satellite group (24-hour sacrifice):
- Observations made for the nose (five levels): the nasal cavity of level 1 to 5 revealed a normal squamous epithelium and a normal respiratory epithelium. The normal respiratory epithelium partially contained cilia consisted of three major cell types: the basal cells above the basement membrane, the ciliated epithelial and the secretory goblet cells. A minimal to mild subepithelial lympho-histiocytic infiltrations or lymphocytic follicles was noted in the respiratory epithelium for nose level 2 to 5 of a few rats.

A normal olfactory epithelium with 5 to 7 nuclear layers, normal basal cells, olfactory sensory cells and sustentacular cells was observed for levels 2 to 5 of all animals.
- Observations made for the lungs (five levels): all 5 lung localizations revealed a normal lung structure. A minimal to mild congestion and a pneumonic foci in one rat are coincidental findings and thus not test item-related.
The trachea of some male and female animals revealed a focal minimal to mild subepithelial lympho-histiocytic inflammatory reactions with normal epithelial cells. The epithelium of the larynx was normal. Some animals revealed a focal minimal lympho-histiocytic infiltration in the subepithelial tissue of the trachea and the larynx.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

LC50 (rats, 4 hours) > 5.05 mg/L air (actual concentration)
Based on the results of the histopathological and macroscopic investigations, vanadium carbide does not require classification for respiratory irritation.
According to the EC Regulation 1272/2008 and subsequent adaptations, vanadium carbide does not meet classification criteria as acute toxic via the inhalation route or as specific target organ toxicity - single exposure.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating conc.

Value:

5 050 mg/m³ air

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Data waiving:

other justification

Justification for data waiving:

other:

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Acute oral toxicity

Speciation:

Upon dissolution, vanadium substances transform in artificial body fluids, including PBS, sweat, gastric juice and lung fluid, predominantlyto the pentavalent form, except in artificial lysosomal fluid; here, even pentavalent forms are converted almost completely to tetravalent species already after a short period of time (for more information on in vitro bioaccessibility testing,please refer IUCLID section 7).Thus, it can be assumed that vanadium speciation in body fluids is controlled by the conditions of the respective medium but not by the vanadium source.

Read-across concept:

The toxicity of vanadium carbide may reasonably be considered to be determined by the bioavailability of vanadium. As a first surrogate for bioavailability, the solubility of a test substance may be used. Under conditions of the transformation/dissolution test (T/D, OECD Series 29) with vanadium carbide powder at a loading of 1 mg/L, dissolved vanadium concentrations after 28d were 41.7 and 27.8 µg V /L at pH 8 and pH 6, respectively. Under similar conditions of the T/D test with vanadium carbide nitride, dissolved vanadium concentrations after 28d at pH 8 and pH 6 were below 1.8 µg V /L while for vanadiun metal powder, dissolved vanadium concentrations after 28d were 38.4 and 39.6 µg V /L at pH 8 and pH 6, respectively. Vanadium carbide (2.1 mg/L; 20°C/pH 5.2), vanadium carbide nitride (0.01 mg/L; 20°C/pH 6.8) and vanadium metal (0.15 mg/L; 20°C/pH 5.8) are substances that are also poorly / sparingly soluble in water. In sum, read-across from vanadium compounds with similar water solubility, i.e. vanadium carbide nitride and vanadium metal, is considered acceptable because kinetic data indicate a similar solubility potential.

Vanadium carbide nitride and vanadium metal powder are non-toxic if swallowed since respective LD50 values (rats, females) are above 2000 mg/kg bw. By read-across based on similar solubility potentials, vanadium carbide is considered to be also non-toxic.

Acute inhalation toxicity

Vanadium carbide is non-toxic if inhaled since the LC50 value (rats, 4 hours) is above 5.05 mg/L air (actual concentration).

Furthermore, vanadium carbide was tested for its potential to become airborne (modified Heubach procedure, DIN 55992-1:2006), yielding MMADs of 4.76 µm (P = 18%) and 27.20 µm (P = 82%) with GSDs of 1.98 and 1.47, respectively. On the basis of results of this dustiness test, MPPD modelling was performed and indicates that the substance does not penetrate to the deep lung tissues (tracheobronchial: 0.5%; pulmonary: 1.1%), whereas the inhaled material (Head: 56.4%) is cleared to the GI tract (by swallowing), where oral bioavailability will determine its uptake. Based on MMAD and MMPD modelling, respiration risk is low and vanadium carbide has a very low potential for human inhalation hazard during handling or application.

Acute dermal toxicity

Acute toxicity testing via the dermal route is not considered to be scientifically justified. However, following the HERAG guidance for metals and metal salts (see section 7.1.2 of the technical dossier, dermal absorption), a dermal absorption rate in the range of maximally 0.1-1.0 % can be anticipated. Dermal absorption in this order of magnitude is not considered to be “significant”.

Justification for selection of acute toxicity – oral endpoint

Two reliable studies conducted with vanadium carbide nitride and vanadium metal are available; read across is performed.

Justification for selection of acute toxicity – inhalation endpoint

There is one reliable study available conducted with vanadium carbide.

Justification for classification or non-classification

The available information indicates that vanadium carbide is not acutely toxic or harmful. Therefore, classification of vanadium carbide for acute toxicity is not required according to Directive 67/548/EEC and Regulation (EC) 1272/2008.

Specific target organ toxicant (STOT) – single exposure

The classification criteria according to Regulation (EC) 1272/2008 as specific target organ toxicant (STOT) – single exposure, oral, inhalation, or dermal are not met since adverse health effects, including reversible and irreversible, were not observed immediately or delayed after exposure.