Phosphorus tribromide

Repeated dose toxicity: inhalation

Administrative data

Endpoint:

short-term repeated dose toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

weight of evidence

Reliability:

4 (not assignable)

Rationale for reliability incl. deficiencies:

data from handbook or collection of data

Justification for type of information:

Data is from NTRL report

Data source

Reference

Reference Type:

other: NTRL

Title:

Acute and Subchronic Toxicity Evaluations of the Halon Replacement Candidate Phosphorus Tribromide.

Author:

Robin E. Wolfe,Marcia L. Feldmann,David H. Ellis,Harry F. Leahy,arlyle D. Flemming,Darol E. Dodd

Year:

1997

Bibliographic source:

Armstrong Laboratory, Occupational and Environmental Health Directorate Toxicology Division, Human Systems Center Air Force Materiel Command,Wright-Patterson, 1997

Materials and methods

Test guideline

Qualifier:

according to guideline

Guideline:

other: Refer below principle

Principles of method if other than guideline:

5 days repeated dose inhalation toxicity study was performed to determine the toxic nature of Phosphorus tribromide upon repeated exposure by inhalation route.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Phosphorus tribromide

EC Number:

232-178-2

EC Name:

Phosphorus tribromide

Cas Number:

7789-60-8

Molecular formula:

Br3P

IUPAC Name:

phosphorus tribromide

Test material form:

liquid

Details on test material:

- Name of test material : Phosphorus tribromide
- Molecular formula: Br3P
- Molecular weight : 270.686 g/mol
- Smiles notation :P(Br)(Br)Br
- InChl :1S/Br3P/c14(2)3
- Substance type: Inorganic
- Physical state: Solid

Specific details on test material used for the study:

- Name of test material: Phosphorus tribromide
- Molecular formula: Br3P
- Molecular weight: 270.686 g/mol
- Substance type: Inorganic
- Physical state: Colourless to pale yellow liquid
- Purity: 99.99+ %
- Impurities (identity and concentrations): No data available

Test animals

Species:

rat

Strain:

Fischer 344

Remarks:

CDF®[F-344]/CrIBR

Details on species / strain selection:

No data

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River Laboratories
- Age at study initiation: No data available
- Weight at study initiation: Males: 100-125g and Females- 75-100 g
- Fasting period before study: No fasting before study
- Housing: the animals (two per cage) were housed in laminar air flow rooms in clear plastic cages with hardwoodchip bedding
- Diet (e.g. ad libitum): Purina Certified Rodent Diet #5002 ad libitum except during the inhalation exposure period
- Water (e.g. ad libitum): Water ad libitum except during the inhalation exposure period and for 12 h prior to sacrifice for the 5-day study
- Acclimation period: 2 weeks

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21 to 25°C
- Humidity (%):No data available
- Air changes (per hr): No data available
- Photoperiod (hrs dark / hrs light): light/dark cycle was set at 12-h intervals

IN-LIFE DATES: From: To: No data available

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Cannon chambers
- Method of holding animals in test chamber: Plexiglas restraining tubes with nose only chambers were used to hold the test animals
- Source and rate of air: Four Cannon nose-only inhalation chambers were supplied with dried laboratory air with a minimal air flow delivery rate of 500 mL/animal
- Method of conditioning air: No data
- System of generating particulates/aerosols: The required concentration of phosphorous tribromide was generated using Sage syringe pumps delivering the required mass of test material into the air supply for the Cannon-52 chambers.
- Temperature, humidity, pressure in air chamber: The temperature of the carrier air was monitored
- Air flow rate: 500 mL/min of dry (<3% RH) filtered house air with a minimum of 10 L/min used for each of the test groups
- Air change rate: No data available
- Method of particle size determination: No data available
- Treatment of exhaust air: A bypass and containment dump system was employed to allow for smooth initiation of exposures and for use as a safety measure in case of abnormal syringe pump operation. The containment areas were further isolated vfrom the general laboratory area through use of a separate exhaust line which vented the enclosures.

TEST ATMOSPHERE
- Brief description of analytical method used: A Bromide specific ion electrode permitted quantification of the test material concentration through analysis of the bromide ion absorbed in an ionic strength buffer (pH 4.0). In order to monitor the lower concentrations, the ratio of vapor sample to buffer had to be increased from 10:1 air/absorber to 20:1 and 40:1. This allowed operation in the linear portion of the response curve. Sixty-mL plastic syringes containing 5.0 mL buffer were used to quantify the 50 mL vapor samples and acted as the reaction vessel for the absorption of PBr3. Multiple absorption samples were required to analyze the lower chamber concentrations.
- Samples taken from breathing zone: No data available

VEHICLE (if applicable)
- Justification for use and choice of vehicle: Air
- Composition of vehicle: No data available
- Type and concentration of dispersant aid (if powder): No data available
- Concentration of test material in vehicle: 0, 0.05, 0.1, and 0.5 mg/L (Mean ± SD exposuer concentrations are 0.06 ± 0.01,0.16 ± 0.03, and 0.51 ± 0.08 mg/L)
- Lot/batch no. of vehicle (if required): No data available
- Purity of vehicle: No data available

Analytical verification of doses or concentrations:

yes

Details on analytical verification of doses or concentrations:

A Bromide specific ion electrode permitted quantification of the test material concentration through analysis of the bromide ion absorbed in an ionic strength buffer (pH 4.0). In order to monitor the lower concentrations, the ratio of vapor sample to buffer had to be increased from 10:1 air/absorber to 20:1 and 40:1. This allowed operation in the linear portion of the response curve. Sixty-mL plastic syringes containing 5.0 mL buffer were used to quantify the 50 mL vapor samples and acted as the reaction vessel for the absorption of PBr3. Multiple absorption samples were required to analyze the lower chamber concentrations.

Duration of treatment / exposure:

Duration of treatment: 1 week
Duration of exposure: 5 days

Frequency of treatment:

4 h/day for 5 consecutive days

Doses / concentrations

Remarks:

0, 0.05, 0.1, and 0.5 mg/L (Mean ± SD exposuer concentrations are 0.06 ± 0.01,0.16 ± 0.03, and 0.51 ± 0.08 mg/L)

No. of animals per sex per dose:

Total: 20
0 mg/L: 5 males
0.05 mg/L: 5 males
0.1 mg/L: 5 males
0.5 mg/L: 5 males

Control animals:

yes, concurrent vehicle

Details on study design:

- Dose selection rationale: The highest concentration of PBr3 was determined considering the results of the acute inhalation toxicity test
- Rationale for animal assignment (if not random): No data
- Rationale for selecting satellite groups: No data
- Post-exposure recovery period in satellite groups: No data
- Section schedule rationale (if not random): No data

Positive control:

No data

Examinations

Observations and examinations performed and frequency:

CAGE SIDE OBSERVATIONS: Yes
- Time schedule: Daily
- Cage side observations checked in table [No.?] were included. Animals were observed for visible signs of toxicity

DETAILED CLINICAL OBSERVATIONS: Yes
- Time schedule: Daily

BODY WEIGHT: Yes
- Time schedule for examinations: terminal body weight was recorded prior to necrospy

FOOD CONSUMPTION AND COMPOUND INTAKE (if feeding study):
- Food consumption for each animal determined and mean daily diet consumption calculated as g food/kg body weight/day: No data available
- Compound intake calculated as time-weighted averages from the consumption and body weight gain data: No data available

FOOD EFFICIENCY:
- Body weight gain in kg/food consumption in kg per unit time X 100 calculated as time-weighted averages from the consumption and body weight gain data: No data available

WATER CONSUMPTION AND COMPOUND INTAKE (if drinking water study): No data available
- Time schedule for examinations: No data available

OPHTHALMOSCOPIC EXAMINATION: No data available
- Time schedule for examinations: No data available
- Dose groups that were examined: No data available

HAEMATOLOGY: Yes
- Time schedule for collection of blood: at necrospy
- Anaesthetic used for blood collection: No data
- Animals fasted: No data available
- How many animals: No data available
- Parameters checked in table [No.?] were examined. WBC, RBC, HGB, HCT, MCV, MCH, MCHC, Platelets, neutrophils, lymphocytes, monocytes, eosinophils, basophils

CLINICAL CHEMISTRY: Yes
- Time schedule for collection of blood: at necropsy
- Animals fasted: No data available
- How many animals: No data available
- Parameters checked in table [No.?] were examined. BUN, creatinine, chloride, calcium, P, Total protein, AST, ALT, Alkaline phosphatase, glucose, Na, Mg, K, Cholesterol, triglycerides, Total bilirubin, ALB/GLOB, CO2, Uric acid, albumin, creatine, kinase and LDH

URINALYSIS: No data available
- Time schedule for collection of urine: No data available
- Metabolism cages used for collection of urine: No data available
- Animals fasted: No data available
- Parameters checked in table [No.?] were examined. No data available

NEUROBEHAVIOURAL EXAMINATION: No data available
- Time schedule for examinations: No data available
- Dose groups that were examined: No data available
- Battery of functions tested: sensory activity / grip strength / motor activity / other: No data available

OTHER:

Sacrifice and pathology:

GROSS PATHOLOGY: Yes, wet tissue weights were determined for heart, kidneys, testes, liver, lungs, brain, spleen, thymus, and adrenal glands at necrospy. Gross pathology was performed on each rat

HISTOPATHOLOGY: Yes, The upper respiratory tract and gross lesions were taken for histopathologic examination.

Other examinations:

No data

Statistics:

Body weights were analyzed using the repeated mUltivariate analysis of variance with Scheffe pairwise comparisons. Hematology, clinical chemistry, and organ weights were analyzed using a two-factorial analysis of variance with multivariate comparisons. Histopathology data were analyzed through use of the Fischer Exact Test, or, if not valid, Yates' Corrected Chi-square was used.

Results and discussion

Results of examinations

Clinical signs:

no effects observed

Mortality:

no mortality observed

Body weight and weight changes:

effects observed, treatment-related

Food consumption and compound intake (if feeding study):

not specified

Food efficiency:

not specified

Water consumption and compound intake (if drinking water study):

not specified

Ophthalmological findings:

not specified

Haematological findings:

effects observed, treatment-related

Clinical biochemistry findings:

effects observed, treatment-related

Urinalysis findings:

not specified

Behaviour (functional findings):

not specified

Immunological findings:

not specified

Organ weight findings including organ / body weight ratios:

no effects observed

Gross pathological findings:

effects observed, treatment-related

Neuropathological findings:

not specified

Histopathological findings: non-neoplastic:

effects observed, treatment-related

Histopathological findings: neoplastic:

not specified

Other effects:

not specified

Details on results:

Clinical signs and mortality
Mortality: No mortality was observed during 5 day exposure period
Clinical signs: No signs of toxic stress were noted dring the 5 day exposure period.

Body weight and weight gain: Mean body weights decreased in 0.05, 0.1 and 0.5 mg/L test groups and were significantly different in the 0.5 mg/L group when compared to control on Study Days 3 and 4.

Food consumption and compound intake: No data available

Food efficiency: No data available

Water consumption and compound intake: No data available

Opthalmoscopic examination: No data available

Haematology: Statistically significant differences between control and PBr3- exposed animals were observed in several mean values hematologic parameters including basophils and monocytes at 0.05 mg/L. Additional statistically significant differences in mean values of hematologic parameters were sporadic and were not considered biologically important.

Clinical chemistry: Statistically significant differences between control and PBr3- exposed animals were observed in several mean values of serum chemistry and hematologic parameters. Increases in serum chloride values were attributable to interference with the presence of serum bromide. Increased values in calcium and potassium were noted in the 0.5 mg/L group. Decreased values when compared to control were observed in alkaline phosphatase and creatine kinase in the 0.5 mg/L group; ALT values in the 0.1 mg/L and 0.5 mg/L groups. Additional statistically significant differences in mean values of hematologic parameters were sporadic and were not considered biologically important.

Urinanalysis: No data available

Neurobehaviour: No data available

Organ weights: No statistically significant differences in the organ weight were noted in the test group as compared to control. Absolute organ weight means and mean organ weight to body weight ratios revealed no statistically significant differences compared to control animals.

Gross pathology: Irregular shaped and reddened nares were observed in 3 of 5 animals at 0.5 mg/L. No other gross pathology lessions were noted in the test group and control animals.

Histopathology: Microscopic lesions were observed in the 0.5 mg/L group and in the anterior-most segment of the nasal passages. In this group, suppurative (acute) inflammation of the mucosa of the nasal passages occurred at a statistically higher incidence than control animals (p<0.05). Chronic ulceration of the epithelium of the external nares was observed in 3 of 5 animals. Minimal squamous metaplasia of the respiratory epithelium was observed in the trachea of one rat in the high concentration group. In the 0.1 mg/L PBr3 group, 1 of 5 rats had slight inflammation of the nasal mucosa (most anterior regions). There were no microscopic lesions in rats of the 0.05 mg/L and control groups.

Effect levels

Dose descriptor:

NOAEC

Effect level:

0.05 mg/L air

Based on:

test mat.

Sex:

male

Basis for effect level:

other: No significant and adverse effect were noted at the mentioned dose level

Target system / organ toxicity

Critical effects observed:

not specified

Any other information on results incl. tables

TABLE 1. Mean body weight of male F-344 rats during five-day, nose-only inhalation exposure to phosphorus tribromide or air

Day	Control	0.05 mg/L	0.1 mg/L	0.5 mg/L
0	258.2 ± 8.0	259.0 ± 10.4	255.6 ± 12.5	258.8 ± 10.7
1	250.4 ±7.9	251.0 ± 10.5	245.3 ± 13.8	247.7 ± 12.6
2	245.4 ± 8.3	245.9 ± 9.4	241.6 ± 12.9	239.9 ± 10.2
3	242.7 ± 9.0	242.9 ± 9.8	237.3 ± 13.1	234.7 ± 9.9^b
4	241.2 ± 9.0	240.5 ± 10.5	236.3 ± 12.0	229.0 ± 8.5^b
5	225.7 ± 8.6	225.2 ± 8.6	220.6 ± 10.6	214.4 ± 7.9

 

a Mean ± SD, N=5.

b Significantly different from control at p<0.01.

TABLE 2. Mean Values· Of Serum Chemistry Parameters For Male F-344 Rats After Five-Day, Nose-Only Inhalation Exposure To Phosphorus Tribromide

Parameter	Control	0.05 mg/L	0.1 mg/L	0.5 mg/L
BUN (mg/dL)	15.8 ± 0.4	13.4 ± 1.3b	15.4 ± 1.1	16.6 ± 1.5
Chloride (mmol/L)	95.0 ± 1.2	99.2 ± 3.5	106.0 ± 1.4c	130.4 ± 3.1 c
Calcium (mmoIlL)	11.6 ± 0.3	11.4 ± 0.5	11.9 ± 0.4	12.4 ± 0.2b
ALT (IU/L)	59.8 ± 5.1	55.0 ±6.4	47.4 ± 6.1 b	38.4 ± 3.7c
Alkaline Phosphatase (lU/L)	151.0 ± 2.9	147.2 ± 12.1	139.0 ± 7.0	132.6 ± 8.4b
Potassium (mmol/L)	4.8 ± 0.3	4.8 ± 0.1	4.7 ± 0.1	5.4 ± 0.2c
Creatine Kinase (lUlL)	69.0 ±6.0	75.0 ± 16.3	59.8 ± 14.4	45.6 ± 10.7 b

a Mean ± SO, N =5.

b Significantly different from control at p<0.05.

c Significantly different from control at p<0.01.

 

TABLE 3. Blood Hematology Values For Male F-344 Rats After Five-Day, Nose-Only Inhalation Exposure To Phosphorus Tribromide

Parameter	Control	0.05 mg/L	0.1 mg/L	0.5 mg/L
Monocytes %)	6.3 ± 0.8	1.2±2.1b	4.4 ± 3.2	6.3 ±3.5
Basophils (%)	0.4 ± 0.2	<0.1 ± <0.1 b	0.2 ± 0.2	0.3 ± 0.2

a Mean ± SD, N = 5.

b Significantly different from control at p<0.05.

 

TABLE 4. Organ Weights and Organ-To-Bodyweight Ratios Of Male F-344 Rats After Five-Day, Nose-Only Inhalation Exposure To Phosphorus Tribromide

Organ	Control	0.05 mg/L	0.1 mg/L	0.5 mg/L
Body Wt	226 ± 8.6	225 ± 8.6	221 ± 10.6	214 ± 7.9
Liver	7.12 ± 0.72	6.88 ± 0.57	6.65 ± 0.37	6.47 ± 0.56
Kidneys	1.77 ± 0.08	1.76 ± 0.08	1.52 ± 0.41	1.68 ± 0.08
Testes	2.84 ± 0.13	2.78 ± 0.09	2.53 ± 0.46	2.65 ± 0.12
Brain	1.79 ± <0.01	1.79 ± 0.04	1.78 ± 0.01	1.74 ± 0.06
Adrenals	0.04 ± 0.02	0.05 ± 0.01	0.05 ± 0.01	0.05 ± 0.01
Lungs	1.45 ± 0.14	1.34 ± 0.10	1.46 ± 0.07	1.09 ± 0.61
Thymus	0.25 ± 0.04	0.22 ± 0.03	0.20 ± 0.03	0.19 ± 0.02
Heart	0.79 ± 0.04	0.81 ± 0.05	0.81 ± 0.02	0.82 ± 0.06

a Mean ± SO, N=5.

b Organ weight/body weight x 100.

Applicant's summary and conclusion

Conclusions:

The No Observed Adverse Effect Concentration (NOAEC) for phosphorus tribromide in a 5 days exposure period is considered to be 0.05 mg/L air.

Executive summary:

5 days repeated dose inhalation toxicity study was performed to determine the toxic nature of Phosphorus tribromide upon repeated exposure by inhalation route. Males CDF®[F-344]/CrIBR rats were treated at dose levels of 0.05, 0.1 or 0.5 mg/L test chemical in vapout form for 4h/days for 5 days by the nose only route of exposure. Mean ± SD exposure concentrations were 0.06 ± 0.01,0.16 ± 0.03, and 0.51 ± 0.08 mg/L respectively. The doses were selected considering the results of acute inhalation toxicity test. Exposures were performed using Cannon chambers. The animals were observed for mortlaity and clinical signs, changes in body weight, hematological and clinical chemistry parameters and gross and histopathology observations were made. The animals did not show any signs of toxic stress or mortality during the 5 days observation period. Mean body weights decreased in 0.05, 0.1 and 0.5 mg/L test groups and were significantly different in the 0.5 mg/L group when compared to control on Study Days 3 and 4. Statistically significant differences between control and PBr3- exposed animals were observed in several mean values of serum chemistry and hematologic parameters. Increases in serum chloride values were attributable to interference with the presence of serum bromide. Increased values in calcium and potassium were noted in the 0.5 mg/L group. Decreased values when compared to control were observed in alkaline phosphatase and creatine kinase in the 0.5 mg/L group; ALT values in the 0.1 mg/L and 0.5 mg/L groups. Additional statistically significant differences in mean values of hematologic parameters were sporadic and were not considered biologically important. No statistically significant differences in the organ weight were noted in the test group as compared to control. Absolute organ weight means and mean organ weight to body weight ratios revealed no statistically significant differences compared to control animals. Irregular shaped and reddened nares were observed in 3 of 5 animals at 0.5 mg/L. No other gross pathology lessions were noted in the test group and control animals. Microscopic lesions were observed in the 0.5 mg/L group and in the anterior-most segment of the nasal passages. In this group, suppurative (acute) inflammation of the mucosa of the nasal passages occurred at a statistically higher incidence than control animals (p<0.05). Chronic ulceration of the epithelium of the external nares was observed in 3 of 5 animals. Minimal squamous metaplasia of the respiratory epithelium was observed in the trachea of one rat in the high concentration group. In the 0.1 mg/L PBr3 group, 1 of 5 rats had slight inflammation of the nasal mucosa (most anterior regions). There were no microscopic lesions in rats of the 0.06 mg/L and control groups. Based on the observations made, the No Observed Adverse Effect Concentration (NOAEC) for phosphorus tribromide in a 5 days exposure period is considered to be 0.05 mg/L air.