Barium nitrate

Endpoint summary

Description of key information

Acute toxicity: oral
One K1 study is available (van Huygevoort, 2013). Under the test conditions a LD50 of 300 mg/kg bw in female Wistar rats was derived. This study was performed according to OECD guideline 423, EU method B.1 tris and EPA OPPTS 870.1100.
Acute toxicity: inhalation
A K2 acute inhalation toxicity test was performed in male and female Wistar rats according to the OECD 403 Guideline (van Huygevoort, 2010) with the read-across substance barium dichloride dihydrate. The acute inhalation LC50 value was derived to be > 1.1 mg/L air (analytical).
Acute toxicity: dermal
Study not required.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

29 January 2013-21 February 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

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 tris (Acute Oral Toxicity - Acute Toxic Class Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1100 (Acute Oral Toxicity)

Deviations:

no

GLP compliance:

yes

Test type:

acute toxic class method

Limit test:

no

Species:

rat

Strain:

other: Wistar strain Crl:WI (Han) (outbred, SPF-Quality).

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: approx. 10 weeks old
- Weight at study initiation: 146-181g .Body weight variation did not exceed +/- 20% of the sex mean
- Fasting period before study: Overnight prior to dosing and until 3-4 hours after administration of the test substance.
- Housing: Group- 3 animals per cage- labeled Makrolon cages (MIV type; height 18 cm.) containing sterilized sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France) and paper as cage-enrichment (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom).
- Diet (e.g. ad libitum): Ad libitum-pelleted rodent diet (SM R/M-Z from SSNIFF® Spezialdiäten GmbH, Soest, Germany).
- Water (e.g. ad libitum): Ad libitum tap water.
- Acclimation period: 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 18 to 24°C
- Humidity (%): 40 to 70%
- Air changes (per hr): 15
- Photoperiod (hrs dark / hrs light): 12-hour light/12-hour dark cycle

IN-LIFE DATES: From: 29 January 2013 To: 21 February 2013

Route of administration:

oral: gavage

Vehicle:

propylene glycol

Details on oral exposure:

VEHICLE
- Concentration in vehicle: varied depending on body weight
- Amount of vehicle (if gavage): 10 mL/kg
- Justification for choice of vehicle: Selected based on trial formulations performed at WIL Research Europe and on test substance data supplied by the sponsor.

MAXIMUM DOSE VOLUME APPLIED: 10mL/kg

DOSAGE PREPARATION (if unusual):To obtain homogeneity, the formulations were heated up to maximally 70 ºC for maximally 30 minutes. The formulations were allowed to cool down to maximally 40 ºC prior to dosing.

CLASS METHOD (if applicable): yes.
The toxicity of the test substance was assessed by stepwise treatment of groups of 3 females. The first group was treated at a dose level of 2000 mg/kg. The absence or presence of mortality of animals dosed at one step determined the next step, based on the test procedure defined in the guidelines. The onset, duration and severity of the signs of toxicity were taken into account for determination of the time interval between the dose groups.

Doses:

2000 mg/kg (10 mL/kg) body weight.
300 mg/kg (10 mL/kg) body weight.
50 mg/kg (10 mL/kg) body weight.

No. of animals per sex per dose:

3

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: At periodic intervals on the day of dosing (Day 1) and once daily thereafter, until Day 15. Body weights recorded at Day 1 and Day 15 (or death).
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs, body weight,organ weights.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 50 - < 300 mg/kg bw

Based on:

test mat.

Mortality:

The three animals dosed at 2000 mg/kg were found dead within 2 hours post-dose. Two (of the three) animals dosed at 300 mg/kg were found dead on Days 1 or 3. No mortality occurred at 50 mg/kg.

Clinical signs:

other: At 2000 mg/kg no clinical signs were noted. At 300 mg/kg hunched posture, flat posture, lethargy, piloerection, uncoordinated movements, labored respiration, slow breathing were noted. At 50 mg/kg hunched posture, piloerection, uncoordinated movements, ch

Gross pathology:

Animals that were found dead had of the jejunum (several reddish foci) in one animal dosed at 2000 mg/kg and abnormalities of the stomach (several dark red foci at the glandular mucosa) and thymus (many dark red foci) in one animal dosed at 300 mg/kg. No test substance related macroscopic abnormalities were seen in the remaining animals found dead or in any of the surviving animals.

Interpretation of results:

Category 3 based on GHS criteria

Conclusions:

The oral LD50 value of barium nitrate in rats was found to be in the range of 50-300 mg/kg body weight. According to the OECD 423 test guideline, the LD50 cut-off value was considered to be 300 mg/kg body weight. This value is used for risk assessment purposes.

Based on these results and according to the Globally Harmonized System of Classification and Labelling of Chemicals (GHS) of the United Nations (2011), Barium Nitrate should be classified as: Toxic if swallowed (Category 3) for acute toxicity by the oral route. According to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures, barium nitrate should be classified as Category 3 and should be labeled as H301: Toxic if swallowed.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

300 mg/kg bw

Acute toxicity: via inhalation route

Link to relevant study records

Reference

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Study period:

2010-07-05 to 2010-07-26

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Version / remarks:

2009-09-07

Deviations:

no

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Sulzfeld, Germany.
- Age at study initiation: Approximately 9 weeks old
- Weight at study initiation: Males (mean weight): 253 g +/- 6 g; Females (mean weight): 165 g +/- 5 g
- Housing: Before exposure: Group housing of five animals per sex per cage in labelled Macrolon cages (type IV; height 18 cm) containing sterilised sawdust as bedding material (Litalabo, S.P.P.S., Argenteuil, France) and paper as cage-enrichment (Enviro-dri, Wm. Lillico & Son (Wonham Mill Ltd), Surrey, United Kingdom). After exposure: Group housing as decribed for before expsoure, except that a paper sheet was introduced into the cage covering the bedding and cage enrichment to prevent suffocation in case of bad health condition. At the end of the Day of exposure the paper sheet was removed.
- Diet (ad libitum except during exposure to the test substance): Pelleted rodent diet (SM R/M from SSNIFF® Spezialdiäten GmbH, Soest, Germany)
- Water (ad libitum except during exposure to the test substance): Tap water
- Acclimation period: At least 5 days before start of treatment under laboratory conditions.

ENVIRONMENTAL CONDITIONS
Animals were housed in a controlled environment.
- Temperature: 21.0 +/- 3.0 °C (actual range: 19.7 - 21.6 °C)
- Relative humidity: 40 - 70 % (actual range: 43 - 79 %)
- Air changes: Approx. 15 air changes per hour
- Photoperiod (hrs dark / hrs light): 12/12
No further information on the test animals was stated.

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Vehicle:

clean air

Details on inhalation exposure:

Before use the test substance was grounded with an automatic grinder (ZM-100, Retsch, Ochten, The Netherlands) and passed through a 150 µm steel mesh sieve.

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: The design of the exposure chamber is based on the flow past nose-only inhalation chamber (Am. Ind. Hyg Assoc. J. 44 (12): 923-928, 1983). The chamber consisted of three animal sections with eight animal ports each. Each animal port had its own atmosphere inlet and exhaust outlet. The animals were placed in polycarbonate restraining tubes and connected to the animal ports. The number of animal sections and number of open inlets were adapted to the air flow in such a way that at each animal port the theoretical air flow was at least 1 L/min, which ensures an adequate oxygen supply to the animals. The main inlet of the test atmosphere was located at the top section and the main outlet was located at the bottom section. The direction of the flow of the test atmosphere guaranteed a freshly generated atmosphere for each individual animal.
All components of the exposure chamber in contact with the test material were made of stainless steel, glass, rubber or plastic. The exposure chamber was placed in a fume hood, which maintained at a slight negative pressure.
Fifteen minutes after the last animal was placed the generation of the test atmosphere was started.

- System of generating particulates/aerosols: The test substance was fed to a stream of pressurized air (mean air flow 28.4 L/min) by means of a spiral feeder (Randcastle Extrusion Systems, Cedar Grove, NJ, USA) and an air mover (type 611210-060, Foxvalve, Dover NJ, USA). The aerosol was passed through a cyclone, allowing larger particles to settle, before it entered the exposure chamber. The rotation speed of the feeder was varied to obtain the desired exposure concentration. Due to the unexpected high usage of test substance, part of the test substance was retrieved from the exposure system, grounded, sieved and used for the continuation of the exposure.
From the exposure chamber the test atmosphere was passed through a filter before it was released to the exhaust of the fume hood.

- Method of particle size determination: The particle size distribution was characterized twice during the exposure period. The samples were drawn (2L/min) from the test atmosphere through a tube mounted in one of the free animal ports of the middle section of the exposure chamber. The samples were collected with an 8 stage Marple personal cascade impactor containing fiber glass filters (SKC 225-713, fiber glass, SKC Omega Specialty Division, Chelmsford, MA, USA) and a fiber glass back-up filter (SEC-290-F1, Westech, Upper Stondon, Bedfordshire, England). Amounts of test substance collected were measured gravimetrically. Subsequently the MMAD and the GSD were determined.

- Temperature, humidity, pressure in air chamber: The temperature and relative humidity were measured with a humidity and temperature indicator (E + E Elektronik, Engerwitzdorf, Austria) and were recorded after the animals were placed in the experimental set-up and at 30 minute intervals after initiation of the exposure. The probe was inserted in a tube mounted in one of the free animal ports of the middle section of the exposure chamber.
The temperature of the atmosphere was between 22.0 and 22.6 °C and relative humidity was between 49 and 58 %.

TEST ATMOSPHERE
- Nominal concentration: The nominal concentration has to be calculated by dividing the amount of test substance used by the volume of pressurized air (average air flow times exposure time) entering the exposure chamber used for exposure of the animals. Since part of the test substance was retrieved from the exposure system but not weighed before use, the exact nominal concentration could not be calculated.
- Brief description of analytical method used: The actual concentration was determined fourteen times during the exposure period. Samples were drawn from the test atmosphere through a tube mounted in one of the free animal ports of the middle section of the exposure chamber. Samples were drawn through a glass fiber filter (type APFC04700, Millipore, Billerica, MA, USA). The collected amount of the test substance in the air sample was measured gravimetrically. Sample volumes were measured by means of a dry gas meter (type G 1.6, Actaris Meterfabriek B.V., Dordrecht, The Netherlands).
The mean concentration with standard deviation was calculated.

TEST ATMOSPHERE
- MMAD / GSD : The MMAD and GSD were determined tiwce. The MMAD was 4.2 µm (GSD 1.6) and 4.2 µm (GSD 1.4) respectively.

- STABILITY MONITORING: The opacity of the test atmosphere exceeded the maximum which could be monitored by means of an aerosol monitoring system. An indication of the stability of the test atmosphere was obtained from the concentration measurements, which were equally distributed over time.
No further information on the inhalation exposure was stated.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

see "details on inhalation exposure" above

Duration of exposure:

240 min

Concentrations:

Mean actual concentration: 1.1 +/- 0.4 mg/L
The nominal concentration was between 44.9 and 89.8 mg/L resulting in a generation efficiency (ratio of actual and nominal concentration) between 1.2 and 2.4 %. Due to the unexpected high usage of test substance, test substance was retrieved from the exposure system and re-used. Since the weight of the retrieved amount was inadvertently not documented, the nominal concentration and efficiency could not be calculated precisely. This did not invalidate the outcome of the study.

No. of animals per sex per dose:

5 males / 5 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing:
- Mortality/Viability: Twice daily. The time of death was recorded as precisely as possible.
- Clinical signs: During exposure: Three times during exposure for mortality, behavioural signs of distress and effects on respiration; After exposure: On Day 1, one and three hours after exposure and once daily thereafter until Day 15. The symptoms were graded according to fixed scales and the time of onset, degree and duration were recorded: Maximum grade 4: grading slight (1) to very severe (4); Maximum grade 3: grading slight (1) to severe (3); Maximum grade 1: presence is scored (1).
- Body weights: Days 1 (pre-administration, 2, 4, 8 and 15
- Necropsy of survivors performed: Yes
The animals surviving to the end of the observation period were sacrificed by an intraperitoneal injection with Euthasol® (AST Farma BV, Oudewater, The Netherlands). All animals assigned to the study were subjected to necropsy and descriptions of all internal macroscopic abnormalities were recorded. Particular attention was given to any changes in the respiratory tract.
No further information on the study design was stated.

Statistics:

No statistical analysis was performed.

Key result

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 1.1 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

243 min

Remarks on result:

other: This value is the mean actual concentration. The standard deviation is 0.4 mg/L.

Mortality:

One male was found dead within three hours after exposure. No further mortality occurred.

Clinical signs:

other: No clinical signs were noted during exposure. After exposure, slow breathing, shallow or laboured respiration, flat or hunched posture, lethargy, hypothermia, piloerection and/or ptosis were noted among the animals on Days 1 and/or 2. One female showed ab

Body weight:

Overall mean body weight gain in surviving males and females was within the range expected for rats of this strain and age used in this type of study.

Gross pathology:

No abnormalities were found at macroscopic post mortem examination of the animals.

Other findings:

No data

Exposure to 1.1 mg/L of barium chloride di-hydrate resulted in significant signs of toxicity (mortality of one male, severe and persisting clinical signs) indicating that significant mortality could be expected at the next higher exposure level of 5 mg/L. In consultation with the sponsor, it was therefore decided not to expose animals to a higher concentration.

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

Based on the results, the inhalatory LC50 (4h) value of barium chloride dihydrate in Wistar rats was considered to exceed 1 mg/L.
According to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures, barium chloride dihydrate should be classified as Category 4 and should be labelled as H332: Harmful if inhaled.
Also, according to 67/548/EC and subsequent regulations, barium chloride dihydrate is classified as harmful by inhalation.

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LC50

Value:

1 100 mg/m³ air

Quality of whole database:

GLP guideline study of 2010

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Acute toxicity: oral

van Huygevoort (2013) investigated the acute oral toxicity in female Wistar rats. This K1 study was performed according to OECD Guideline 423, EU method B.1 tris and EPA OPPTS 870.1100. The substance was formulated in propylene glycol and administered by oral gavage. The toxicity was assessed by stepwise treatment of groups of 3 females at doses of 2000 (first dose), 300 and 50 mg/kg bw. Animals were observed for a period of 14 days.

The three animals dosed at 2000 mg/kg were found dead within 2 hours post-dose. Two (of the three) animals dosed at 300 mg/kg were found dead on Days 1 or 3. No mortality occurred at 50 mg/kg. Clinical signs were observed at all the doses but the surviving animals recovered from the symptoms between Days 2 and 3.

The oral LD50 value of barium nitrate in rats was found to be in the range of 50-300 mg/kg body weight. According to the OECD 423 test guideline, the LD50 cut-off value was considered to be 300 mg/kg body weight.

In addition, the acute oral LD50 value of the read-across substance barium chloride in male and female Sprague-Dawley derived CD rats was 419 and 408 mg/kg respectively (Borzelleca, 1988). The study was performed equivalent to OECD Guideline 401.

Acute toxicity: inhalation

van Huygevoort (2010) investigated the acute inhalation toxicity with the read-across substance barium dichloride dihydrate in male/female Wistar rats (5 animals/sex/group). The study was performed according to OECD guideline 403. Animals were exposed (nose only) to the substance as aerosol for 240 minutes (4 -hrs). The test substance data indicated that significant mortality could be expected at the limit concentration of 5 mg/L. Therefore animals were exposed to the next lower concentration of 1.1 mg/L (the cut off value of the guideline was increased with 10% in order to avoid the mean actual concentration to fall below the cut off value due to experimental variation. The mean actual concentration was 1.1 +/- 0.4 mg/L. The nominal concentration was between 44.9 and 89.8 mg/L resulting in a generation efficiency (ratio of actual and nominal concentration) between 1.2 and 2.4 %. Due to the unexpected high usage of test substance, test substance was retrieved from the exposure system and re-used. Since the weight of the retrieved amount was inadvertently not documented, the nominal concentration and efficiency could not be calculated precisely. This did not invalidate the outcome of the study. The MMAD was 4.2 µm (GSD 1.6) and 4.2 µm (GSD 1.4) respectively.

Animals were observed for 14 days. One female was found dead within three hours after exposure. No further mortality occurred.

The acute inhalation LC50 value was derived to be > 1.1 mg/L air (analytical). Since according to regulation(EC) 272/2008 the threshold value for LC50 is >= 1 mg/L, it can reasonably be stated that the LC50 of barium chloride is > 1 mg/L.

This study was considered reliable with restrictions (K2) to reflect the read-across status. The read across justification is added in Section 13 of IUCLID.

Acute toxicity: dermal

A key study is available for the oral route of exposure and data are available for the inhalation route of exposure from the read-across substance barium dichloride dihydrate. According to the REACH Regulation, only one additional route of exposure should be tested other than the oral route of exposure for acute toxicity (column 2, annex VIII, section 8.5). Therefore, it is not necessary to perform an acute toxicity study via the dermal route of exposure.

Justification for selection of acute toxicity – oral endpoint
Only study on barium nitrate available

Justification for selection of acute toxicity – inhalation endpoint
Only one reliable study available (read-across from barium dychloride dihydrated). This study was performed with a limit concentration of 1.1 mg/L barium chloride dihydrate which relates to a concentration of 0.94 mg/L barium chloride. Exposure to 1.1 mg/L of barium chloride dihydrate resulted in significant signs of toxicity (mortality of one male, severe and persisting clinical signs) indicating that significant mortality could expected at the next higher exposure level of 5 mg/L. Due to animal welfare reasons, it was therefore decided not expose animals to a higher concentration. Instead, since according to regulation (EC) 1272/2008 the threshold value for LC50 is >= 1 mg/L, it can reasonably be stated that the LC50 of barium chloride is > 1 mg/L.

Justification for selection of acute toxicity – dermal endpoint
According to the REACH Regulation, only one additional route of exposure should be tested other than the oral route of exposure for acute toxicity (column 2, annex VIII, section 8.5). Therefore, it is not necessary to perform an acute toxicity study via the dermal route of exposure.

Justification for classification or non-classification

Based on the available data on barium nitrate and according to the criteria of the DSD and CLP Regulation, barium nitrate should be classified as R25 and as acute oral toxicant category 3, H301 (toxic if swallowed).

Based on the available read-across data of barium chloride dihydrate and according to the DSD and CLP Regulation, barium nitrate should be classified as R20 and acute inhalation toxicant category 4, H332: Harmful if inhaled.

Specific target organ toxicant (STOT) – single exposure: inhalation
The classification criteria according to regulation (EC) 1272/2008 as specific target organ toxicant (STOT) – single exposure, inhalation are not met since no reversible or irreversible adverse health effects were observed immediately or delayed after exposure and no effects were observed at the guidance value, inhalation for a Category 1 classification of <= 1 mg/L/4h and at the guidance value, inhalation for a Category 2 <= 5 mg/L/4h - > 1 mg/L/4h. No additional classification required.