Barium nitrate

Endpoint summary

Description of key information

Skin irritation:
van Huygevoort (2013) determined, in a K1 study, the skin irritation potential of barium nitrate in New Zealand White rabbits according to OECD Guideline 404, EU Method B.4 and EPA OPPTS 870.2500. Barium nitrate was observed to be non irritating to the skin. 
In addition, Verbaan (2013) determined the skin irritation potential of barium nitrate in a K1 in vitro skin irritation test (EPISKIN Small Model) according to OECD Guideline 439 and EU method B.46.
The in vivo skin irritation test of van Huygevoort (2013) was selected as key study as an in vivo skin irritation test is more reliable than an in vitro test.
Eye irritation:
van Huygevoort (2013) determined, in a K1 study, the eye irritation potential of barium nitrate in New Zealand White rabbits according to OECD Guideline 405, EU Method B.5 and EPA OPPTS 870.2400. Barium nitrate was observed to be irritating to the eye. 
In addition, Verspeek-Rip (2013) determined the eye irritation potential of barium nitrate in a K1 in vitro test using the bovine corneal opacity and permeability test (bcop test) according to OECD Guideline 437 and EU method B.47.
The in vivo eye irritation test of van Huygevoort (2013) was selected as key study as an in vivo eye irritation test is more reliable than an in vitro test.

Key value for chemical safety assessment

Skin irritation / corrosion

Link to relevant study records

Reference

Endpoint:

skin irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

From 15 January 2013 to 25 January 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented GLP study performed according to OECD Guideline 404, EU Method B.4 and EPA OPPTS 870.2500.

Qualifier:

according to guideline

Guideline:

OECD Guideline 404 (Acute Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.4 (Acute Toxicity: Dermal Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2500 (Acute Dermal Irritation)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Deutschland, Kissleg, Germany
- Age at study initiation: Animals used within the study were at least 8 weeks old
- Weight at study initiation: at least 1 kg
- Housing: Animals were individually housed in labeled cages with perforated floors (dimensions 67 x 62 x 55 cm) and shelters (dimensions 40 x 32 x 23 cm)
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): ad libitum
- Acclimation period: at least 5 days before the start of treatment under laboratory conditions

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

Type of coverage:

semiocclusive

Preparation of test site:

clipped

Vehicle:

unchanged (no vehicle)

Remarks:

the substance was moistened with 0.1mL of water

Controls:

no

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): 0.5 grams

VEHICLE
The test substance was moistened with 0.1 mL of the vehicle

Duration of treatment / exposure:

4 hours

Observation period:

Mortality/viability: twice daily
Toxicity: at least once daily
Body weight: day of treatment (prior to application) and after the final observation
Necropsy: No necropsy was performed according to protocol
Irritation: The skin reactions were assessed at approximately 1, 24, 48 and 72 hours after the removal of the dressings and test substance. The irritation scores and a description of all other (local) effects were recorded. Adjacent areas of the untreated skin of each animal served as controls.
No histopathology was performed.

Number of animals:

3 males

Details on study design:

TEST SITE
- Area of exposure: dorsal fur was clipped with electric clippers, exposing an area of approximately 150 square centimeters (10x15 cm). To facilitate scoring, treated skin areas were re-clipped at least 3 hours before the observations.
- Type of wrap if used: The patch was mounted on Micropore tape, which was wrapped around the abdomen and secured with Coban elastic bandage.

REMOVAL OF TEST SUBSTANCE
- Washing (if done): Four hours after the application, the dressing was removed and the skin cleaned of residual test substance using tap water.

SCORING SYSTEM:
The irritation was assessed according to the following numerical scoring system. At each observation, the highest scores given were recorded.
Erythema and eschar formation: scores from 0 to 4
Oedema formation: scores from 0 to 4

Irritation parameter:

erythema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritation parameter:

edema score

Basis:

mean

Time point:

24/48/72 h

Score:

0

Max. score:

4

Reversibility:

other: not applicable

Irritant / corrosive response data:

Irritation: No skin irritation was caused by 4 hours exposure to barium nitrate.
Corrosion: There was no evidence of a corrosive effect on the skin.
Coloration/remnants: No staining of the treated skin by the test substance was observed and no test substance remnants were seen.

Other effects:

Toxicity/mortality: No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred.

Interpretation of results:

GHS criteria not met

Conclusions:

Based on these results barium nitrate does not have to be classified and no obligatory labelling requirement for skin irritation according to Globally Harmonized System of classification and Labelling of Chemicals (GHS) of the United Nations (2011) and Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed (not irritating)

Eye irritation

Link to relevant study records

Reference

Endpoint:

eye irritation: in vivo

Type of information:

experimental study

Adequacy of study:

key study

Study period:

21 January 2013 - 12 February 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Well documented study in accordance with OECD Guidelines for Testing of Chemicals, Section 4, Health Effects, No.405, (EC) No 440/2008 Part B5; EPAOPPTS 870.2400.

Qualifier:

according to guideline

Guideline:

OECD Guideline 405 (Acute Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.5 (Acute Toxicity: Eye Irritation / Corrosion)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.2400 (Acute Eye Irritation)

Deviations:

no

GLP compliance:

yes

Species:

rabbit

Strain:

New Zealand White

Details on test animals or tissues and environmental conditions:

TEST ANIMALS
- Source: Charles River France, L’Arbresle Cedex, France
- Age at study initiation: At least 8 weeks.
- Weight at study initiation: At least 1.0 kg.
- Housing: Individually housed in labeled cages with perforated floors (Ebeco, Germany, dimensions 67 x 62 x 55 cm) and shelters (Ebeco, Germany, dimensions 40 x 32 x 23 cm).
- Diet (e.g. ad libitum):Approximately 100 grams/day of pelleted diet for rabbits (Global Diet 2030 from Harlan Teklad®, Mucedola, Milanese, Italy).
- Water (e.g. ad libitum): Ad libitum tap water.
- Acclimation period: At least 5 days.

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

IN-LIFE DATES: From: 21 January 2013 To: 12 February 2013

Vehicle:

unchanged (no vehicle)

Controls:

other: One eye of each animal was left untreated as a reference control.

Amount / concentration applied:

TEST MATERIAL
- Amount(s) applied (volume or weight with unit):62.6 mg (range 62.2 – 63.0 mg). Equivalent to approximately 0.1 mL.

Duration of treatment / exposure:

24 hrs.

Observation period (in vivo):

14 days

Number of animals or in vitro replicates:

3

Details on study design:

REMOVAL OF TEST SUBSTANCE
- Washing (if done): None. 2% fluorecein stain was instilled to determine corneal damage.
- Time after start of exposure: 24 hr

SCORING SYSTEM: 1-4 for corneal irritation, iris, conjunctival irritation, chemosis, and discharge.

TOOL USED TO ASSESS SCORE: fluorescein

Irritation parameter:

cornea opacity score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Irritation parameter:

iris score

Basis:

animal #1

Time point:

24/48/72 h

Score:

0

Max. score:

1

Reversibility:

fully reversible within: 24 hr

Irritation parameter:

conjunctivae score

Basis:

animal #1

Time point:

24/48/72 h

Score:

2.7

Max. score:

3

Reversibility:

fully reversible within: 14 d

Irritation parameter:

chemosis score

Basis:

animal #1

Time point:

24/48/72 h

Score:

1.7

Max. score:

3

Reversibility:

fully reversible within: 7 d

Irritation parameter:

cornea opacity score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0

Irritation parameter:

iris score

Basis:

animal #2

Time point:

24/48/72 h

Score:

0.3

Max. score:

1

Reversibility:

fully reversible within: 48 hr

Irritation parameter:

conjunctivae score

Basis:

animal #2

Time point:

24/48/72 h

Score:

2.3

Max. score:

3

Reversibility:

fully reversible within: 14 d

Irritation parameter:

chemosis score

Basis:

animal #2

Time point:

24/48/72 h

Score:

1.3

Max. score:

2

Reversibility:

fully reversible within: 7 d

Irritation parameter:

cornea opacity score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0

Irritation parameter:

iris score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.3

Max. score:

1

Reversibility:

fully reversible within: 48 hr

Irritation parameter:

conjunctivae score

Basis:

animal #3

Time point:

24/48/72 h

Score:

1.7

Max. score:

2

Reversibility:

fully reversible within: 7 d

Irritation parameter:

chemosis score

Basis:

animal #3

Time point:

24/48/72 h

Score:

0.7

Max. score:

2

Reversibility:

fully reversible within: 72 hr

Irritant / corrosive response data:

Instillation of approximately 63 mg of barium nitrate (a volume of approximately 0.1 mL) into one eye of each of three rabbits resulted in effects on the iris and conjunctivae. Iridial irritation grade 1 was observed and resolved within 24 hours in one animal and within 48 hours in the other two animals. The irritation of the conjunctivae consisted of redness, chemosis and discharge and completely resolved within 7 days in one animal and within 14 days in the other two animals.
No corneal opacity was observed, and treatment of the eyes with 2% fluorescein 24 hours after test substance instillation revealed no corneal epithelial damage.

Other effects:

There was no evidence of ocular corrosion. No staining of (peri) ocular tissues by the test substance was observed and no test substance remnants were seen. No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred. The body weight gain shown by the animals over the study period was considered to be similar to that expected of normal untreated animals of the same age and strain.

Interpretation of results:

Category 2 (irritating to eyes) based on GHS criteria

Conclusions:

Barium nitrate was found to cause irritation to the rabbit eye. Since the redness of the conjunctivae exceeded the classification threshold of 2 in two (of the three) animals which did not recover within 7 days, 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 irritating to eyes (Category 2A). According to the Regulation (EC) No 1272/2008 on classification, labelling and packaging of substances and mixtures, barium nitrate should be classified as irritating to eyes (Category 2) and labeled as H319 (causes serious eye irritation).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed (irritating)

Respiratory irritation

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Skin irritation / corrosion

van Huygevoort (2013) studied the skin irritation/corrosion potential of barium nitrate by applying the susbtance on one intact site on the upper dorsal trunk. The dorsal fur was clipped with electric clippers, exposing an area of approximately 150 square centimeters (10x15 cm). Four hours after the application, the dressing was removed and the skin cleaned of residual test substance using tap water.

The irritation was assessed according to the following numerical scoring system. At each observation, the highest scores given were recorded.

Erythema and eschar formation: scores from 0 to 4

Oedema formation: scores from 0 to 4

No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred. No staining of the treated skin by the test substance was observed and no test substance remnants were seen.

No skin irritation was caused by 4 hours exposure to barium nitrate.

This study is selected as key study.

In addition, Verbaan (2013) studied the skin irritation potential of barium nitrate in an in vitro skin irritation test using a human skin model (Episkin). The possible skin irritation potential was tested through topical application for 15 minutes. Barium nitrate was applied directly on top of the skin tissue for 15 minutes. After a 42 hour incubation period, determination of the cytotoxic (irritancy) effect was performed. Cytotoxicity is expressed as the reduction of mitochondrial dehydrogenase activity measured by formazan production from MTT at the end of the treatment.

Skin irritation is expressed as the remaining cell viability after exposure to the test substance. The relative mean tissue viability obtained after 15 minutes treatment with barium nitrate compared to the negative control tissues was 102%. Since the mean relative tissue viability for barium nitrate was above 50% after 15 minutes treatment barium nitrate is considered to be non-irritant.

The positive control has a mean cell viability of 31% after 15 minutes exposure. The absolute mean OD570 (optical density at 570 nm) of the negative control tissues was within the laboratory historical control data range. The standard deviation value of the percentage viability of three tissues treated identically with test substance, negative and positive control was less than 15%, indicating that the test system functioned properly.

It was concluded that this test is valid and that barium is non-irritant in the in vitro skin irritation test under the experimental conditions described in the report.

Eye irritation / corrosion

van Huygevoort (2013) studied the eye irritation/corrosion potential of barium nitrate by applying the susbtance in the eye of three New Zealand rabbits. Approximately 62.6 mg (equivalent to 0.1 mL) were applied for a duration of 24 hours. Fluoresceine was used to assess the effects. Iridial irritation grade 1 was observed and resolved within 24 hours in one animal and within 48 hours in the other two animals. The irritation of the conjunctivae consisted of redness, chemosis and discharge and completely resolved within 7 days in one animal and within 14 days in the other two animals.
No corneal opacity was observed, and treatment of the eyes with 2% fluorescein 24 hours after test substance instillation revealed no corneal epithelial damage. There was no evidence of ocular corrosion. No staining of (peri) ocular tissues by the test substance was observed and no test substance remnants were seen. No symptoms of systemic toxicity were observed in the animals during the test period and no mortality occurred. The body weight gain shown by the animals over the study period was considered to be similar to that expected of normal untreated animals of the same age and strain. It was concluded that barium nitrate was found to cause irritation to the rabbit eye.

This study is selected as key study.

In addition, Verspeek-Rip (2013) determined the eye irritation potential of barium nitrate in a K1 in vitro test using the bovine corneal opacity and permeability test (bcop test). The purpose of this study was to determine the eye irritation potential of the test material after a treatment period of approximately 240 minutes. The individual in vitro irritancy scores for the negative controls ranged from 0.0 to 1.0. The negative control responses for opacity and permeability were less than the upper limits of the laboratory historical range indicating that the negative control did not induce irritancy. The individual positive control in vitro irritancy scores ranged from 72 to 156. The mean in vitro irritancy score of the positive control was 111 and within the historical positive control data range. Therefore the test conditions were adequate and the test system valid.

The mean in vitro irritancy score for barium bitrate was below 55.1 after 240 minutes treatment thus barium nitrate is considered not to be a severe irritant or corrosive under the experimental conditions of this study.

Justification for selection of skin irritation / corrosion endpoint:
In vivo test is more reliable than in vitro test

Justification for selection of eye irritation endpoint:
In vivo test is more reliable than in vitro test

Effects on eye irritation: irritating

Justification for classification or non-classification

Based on the available data and according to the criteria of the DSD and CLP Regulation, barium nitrate should not be classified as irritating to the skin.

Based on the available data and according to the criteria of the DSD and CLP Regulation, barium nitrate should be classified as irritating to eyes, R36 and category 2 eye irritant, H319 (causes serious eye irritation).