Boron orthophosphate

Endpoint summary

Description of key information

Oral (according to OECD 420), rat: > 300 - < 2000 mg/kg bw
Inhalation (according to OECD 436), rat: > 5.31 mg/L (limit test)

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:

02 Oct - 13 Nov 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 420 (Acute Oral Toxicity - Fixed Dose Method)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.1 bis (Acute Oral Toxicity - Fixed Dose Procedure)

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The department of health of the government of the United Kingdom

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Limited, Oxon, UK
- Age at study initiation: 8-12 weeks
- Weight at study initiation: The bodyweight variation did not exceed ± 20% of the initial/mean bodyweight of any previously dosed animal(s).
- Fasting period before study: overnight fast immediately before dosing
- Housing: The animals were housed in groups of up to four in suspended solid-floor polypropylene cages furnished with woodflakes.
- Diet: ad libitum (2014C Teklad Global Rodent diet supplied by Harlan Teklad, Oxon, UK)
- Water: ad libitum; drinking water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 30-70
- Air changes (per hr): at least 15 per hour
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

oral: gavage

Vehicle:

other: distilled water

Details on oral exposure:

For the purpose of the study the test item was freshly prepared, as required, as a suspension in distilled water.
The test item was formulated within two hours of being applied to the test system. It is assumed that the formulation was stable for this duration.
No analysis was conducted to determine the homogeneity, concentration or stability of the test item formulation. This is an exception with regard to GLP and has been reflected in the GLP compliance statement.

Doses:

300 and 2000 mg/kg bw

No. of animals per sex per dose:

5

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Clinical observations were made ½, 1, 2, and 4 hours after dosing and subsequently once daily for 14 days. Morbidity and mortality checks were made twice daily. Individual bodyweights were recorded on Day 0 (the day of dosing) and on Days 7 and 14.
- Necropsy of survivors performed: yes
At the end of the observation period the animals were sacrificed by cervical dislocation. All animals were subjected to gross necropsy. This consisted of an external examination and opening of the abdominal and thoracic cavities. The appearance of any macroscopic abnormalities was recorded. No tissues were retained.

Preliminary study:

The starting dose in the sighting test was 300 mg/kg bw administered to one female. No mortality was observed, but hunched posture was noted during the day of dosing.

Sex:

female

Dose descriptor:

LD50

Effect level:

> 300 - < 2 000 mg/kg bw

Based on:

test mat.

Mortality:

Dose level: 2000 mg/kg bw
Two animals were found dead during the day of dosing or two days after dosing. One animal was sacrificed for humane reasons, due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home Office Project Licence, four days after dosing (see table 1).

Dose Level: 300 mg/kg bw
There were no deaths.

Clinical signs:

other: Dose level: 2000 mg/kg bw: There were no signs of systemic toxicity noted in the initial treated animal. Hunched posture was noted in 3/4 of the additional treated animals. Signs of systemic toxicity noted in one animal were lethargy, ataxia, pilo-erectio

Gross pathology:

Dose level: 2000 mg/kg bw:
Individual necropsy findings are given in Table 3.
Haemorrhagic, ulcerated and epithelial sloughing of the gastric mucosa were noted at necropsy of the animals that died during the study. Abnormalities noted at necropsy of the animal that was sacrificed due to humane reasons during the study were patchy pallor of the liver and gaseous stomach and small and large intestines. No abnormalities were noted in the surviving animals

Dose Level: 300 mg/kg bw:
Individual necropsy findings are given in Table 6.
No abnormalities were noted at necropsy.

Table 1. Individual clinical observations and mortality data – 2000 mg/kg bw

Dose level mg/kg bw	Animal number and sex	Effects noted after dosing (hours)				Effects noted during periods after doing (days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	2-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	*	0	0	0	0
	3-0 Female	H	H	H	0	0	X
	3-1 Female	H	H	H	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	3-2 Female	X°
	3-3 Female	H	HL	H	0	0	0	HPARlEm	HPALRl RdEmDhX*

 

= No signs of systemic toxicity

H = Hunched posture

L = Lethargy

A = Ataxia

P = Pilo-erection

Em = Emaciation

Rl = Laboured respiration

Rd = Decreased respiratory rate

Dh = Dehydration

X = Animal dead

X° = Animal found dead 18 minutes after dosing

X* = Animal sacrificed for humane reasons, due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home

Office Project Licence 

 

 Table 2. Individual bodyweight and bodyweight changes– 2000 mg/kg bw

Dose level mg/kg	Animal number and sex	Bodyweight (g) at day			Bodyweight (g) at Death	Bodyweight gain (g) during week
		0	7	14		1	2
2000	2-0 Female	169	180	190		11	10
	3-0 Female	157	-	-	149	-	-
	3-1 Female	166	194	207		28	13
	3-2 Female	151	-	-	151	-	-
	3-3 Female	154	-	-	116	-	-

- = animal dead

 

Table 3. Individual Necropsy Findings – 2000 mg/kg bw

Dose level mg/kg	Animal number and sex	Time of death	Macroscopic observations
2000	2-0 Female	Killed day 14	No abnormalities detected
	3-0 Female	Found dead Day 2	Gastric mucosa: haemorrhagic epithelial sloughing
	3-1 Female	Killed day 14	No abnormalities detected
	3-2 Female	Found dead Day 2	Gastric mucosa: haemorrhagic ulcerated
	3-3 Female	Humanely killed Day 4	Liver: patchy pallor Stomach: gaseous Small intestine: gaseous Large intestine: gaseous

 

 

Table 4. Individual clinical observations and mortality data.– 300 mg/kg bw

Dose level mg/kg	Animal number and sex	Effects noted after dosing (hours)				Effects noted during periods after doing (days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
300	1-0 Female	H	H	H	H	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	4-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	4-1 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	4-2 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	4-3 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

 

0 = No signs of systemic toxicity

H = Hunched posture

 

 

Table 5. Individual bodyweight and bodyweight changes– 300 mg/kg bw

Dose level mg/kg	Animal number and sex	Bodyweight (g) at day			Bodyweight gain (g) during week
		0	7	14	1	2
300	1-0 Female	158	184	200	26	16
	4-0 Female	142	156	182	14	26
	4-1 Female	159	164	188	5	24
	4-2 Female	148	152	174	4	22
	4-3 Female	155	165	182	10	17

 

 

 Table 6. Individual Necropsy Findings– 300 mg/kg bw

Dose level mg/kg	Animal number and sex	Time of death	Macroscopic observations
300	1-0 Female	Killed day 14	No abnormalities detected
	4-0 Female	Killed day 14	No abnormalities detected
	4-1 Female	Killed day 14	No abnormalities detected
	4-2 Female	Killed day 14	No abnormalities detected
	4-3 Female	Killed day 14	No abnormalities detected

 

Interpretation of results:

Category 4 based on GHS criteria

Conclusions:

CLP: Cat. 4, H302

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

300 mg/kg bw

Quality of whole database:

The available information comprises an adequate and reliable study, and is thus sufficient to fulfil the standard information requirements set out in Annex VII, 8.5, of Regulation (EC) No 1907/2006.

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:

19 Sep - 08 Oct 2012

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

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

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Remarks:

The department of health of the government of the United Kingdom

Test type:

acute toxic class method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Further details on strain: RccHanTM : WIST strain rats
- Source: Harlan Laboratories UK Ltd, Oxon, UK
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 200-350 g
- Housing: The animals were housed in groups of up to three by sex in solid-floor polypropylene cages with stainless steel lids, furnished with softwood flakes (Datesand Ltd., Cheshire, UK) and provided with environmental enrichment items: wooden chew blocks and cardboard “fun tunnels” (Datesand Ltd., Cheshire, UK).
- Diet: with the exception of the exposure period diet (Harlan 2014C Rodent Diet, Harlan Laboratories UK Ltd, Oxon, UK) was available ad libitum
- Water: with the exception of the exposure period water was available ad libitum, drinking water
- Acclimation period: at least 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19-25
- Humidity (%): 30-70
- Air changes (per hr): at least 15
- Photoperiod (hrs dark / hrs light): 12/12

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: A dust atmosphere was produced from the test item using a SAG 410 Solid Aerosol Generator (TOPAS GmbH, Dresden, Germany) located adjacent to the exposure chamber. The SAG 410 was connected to a metered compressed air supply.
Compressed air was supplied by means of an oil free compressor and passed through a water trap and respiratory quality filters before it was introduced to the SAG 410.
- Exposure chamber volume: 30 litres (dimensions: 28 cm diameter x 50 cm high)
-Chamber flow rate: The chamber flow rate was maintained at 60 L/min providing 120 air changes per hour.
- Method of holding animals in test chamber: each rat was individually held in a tapered, polycarbonate restraining tube fitted onto a single tier of the exposure chamber and sealed by means of a rubber ‘O’ ring. Only the nose of each animal was exposed to the test atmosphere.
- Method of conditioning air: The concentration within the chamber was controlled by adjusting the test item feed rate from the SAG 410. The extract from the exposure chamber passed through a ‘scrubber’ trap and was connected with a high efficiency filter to a metered exhaust system. The chamber was maintained under negative pressure.
- System of generating particulates/aerosols: In order to facilitate aerosolisation and reduce particle size, the test item was ground using a small amount of diethyl ether in a Retsch Planetary Ball Mill (Retsch (UK) Ltd, Leeds, UK) all of the solvent was removed via evaporation prior to use. The absorption of the test item was not determined.
- Method of particle size determination: The particle size of the generated atmosphere inside the exposure chamber was determined three times during the exposure period using a Marple Personal Cascade Impactor (Westech IS Ltd, Beds., UK). This device consisted of six impactor stages (8.6, 5.5, 3.8, 1.7, 0.86 and 0.41 μm cut points) with stainless steel collection substrates and a back up glass fibre filter, housed in an aluminium sampler. The sampler was temporarily sealed in a sampling port in the animals’ breathing zone and a suitable, known volume of exposure chamber air was drawn through it using a vacuum pump.
The collection substrates and backup filter were weighed before and after sampling and the weight of test item, collected at each stage, calculated by difference.
The mean amount for each stage was used to determine the cumulative amount below each cut-off point size. In this way, the proportion (%) of aerosol less than 8.6, 5.5, 3.8, 1.7, 0.86 and 0.41 μm was calculated.
The resulting values were converted to probits and plotted against Log10 cut-point size. From this plot, the Mass Median Aerodynamic Diameter (MMAD) was determined (as the 50% point) and the geometric standard deviation was calculated. In addition the proportion (%) of aerosol less than 4 μm (considered to be the inhalable fraction) was determined.
- Temperature, humidity, pressure in air chamber: The temperature and relative humidity inside the exposure chamber were measured by an electronic thermometer/humidity meter (Hanna Instruments Ltd, Beds., UK) located in a vacant port in the animals’ breathing zone of the chamber and recorded every thirty minutes throughout the four-hour exposure period.
-Exposure chamber oxygen concentration: Oxygen levels within the exposure chamber were measured by an electronic oxygen analyser (Servomex (UK) Ltd, Crowborough, East Sussex) located in a port in the animals breathing zone during the four-hour exposure period. The test atmosphere was generated to contain at least 19% oxygen.

TEST ATMOSPHERE
- Brief description of analytical method used: Homogeneity of the test atmosphere within the chamber was not specifically determined during this study. Chambers of the same design (ADG Developments Ltd, Hitchin, Herts, UK) have been fully validated and shown to produce evenly distributed atmospheres in the animals’ breathing zone with a wide variety of test items (Green, J. et al, 1984).
Prior to the start of the study, test item atmospheres were generated within the exposure chamber. During this characterisation period test item input rates, grinding techniques and generation systems were varied in order to achieve the required atmospheric conditions.
- Samples taken from breathing zone: yes
The actual chamber concentration was measured at regular intervals during the exposure period. The gravimetric method used glass fibre filters placed in a filter holder. The holder was temporarily sealed in a vacant port in the exposure chamber in the animals’ breathing zone and a suitable, known volume of exposure chamber air was drawn through the filter using a vacuum pump.
Each filter was weighed before and after sampling in order to calculate the weight of collected test item. The difference in the two weights, divided by the volume of atmosphere sampled, gave the actual chamber concentration.
The nominal chamber concentration was calculated by dividing the mass of test item used by the total volume of air passed through the chamber.
The nominal concentration is 243 % of the actual mean achieved atmosphere concentration and shows that keeping the aerosol airborne was moderately difficult.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5 mg/L

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: All animals were observed for clinical signs at hourly intervals during exposure, immediately on removal from the restraining tubes at the end of exposure, one hour after termination of exposure and subsequently once daily for up to fourteen days. Any evidence of overt toxicity was recorded at each observation.
- Bodyweight: Individual bodyweights were recorded on arrival, prior to treatment on the day of exposure and on Days 1, 3, 7 and 14.
- Necropsy of survivors performed: yes
At the end of the fourteen day observation period the animals were sacrificied by intravenous overdose of sodium pentobarbitone. All animals were subjected to a full external and internal examination, and any macroscopic abnormalities were recorded. The respiratory tract was subjected to a detailed macroscopic examination for signs of irritancy or local toxicity.

Statistics:

Evaluation of Data
Data evaluations included the relationship, if any, between the animals’ exposure to the test item and the incidence and severity of all abnormalities including behavioural and clinical observations, necropsy findings, bodyweight changes, mortality and any other toxicological effects.
Using the mortality data obtained, an estimate of the acute inhalation median lethal concentration (LC50) of the test item was made.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.31 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

There was no mortality.

Clinical signs:

other: Signs of hunched posture, pilo-erection and red/brown staining around the eyes or snout are commonly seen in animals for short periods on removal from the chamber following 4-hour inhalation studies. Wet fur is commonly recorded both during and for a shor

Body weight:

Two males and two female animals exhibited bodyweight losses on the first day post-exposure. All animals exhibited bodyweight gains during the remainder of the recovery period.

Gross pathology:

No macroscopic abnormalities were detected amongst animals at necropsy.

Interpretation of results:

GHS criteria not met

Conclusions:

CLP: not classified

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

5 000 mg/m³ air

Quality of whole database:

The available information comprises an adequate and reliable study, and is thus sufficient to fulfil the standard information requirements set out in Annex VII-VIII, 8.5, of Regulation (EC) No 1907/2006.

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

The acute oral toxicity was investigated in rats according to OECD 420 and in compliance with GLP (Bradshaw, 2013). The test substance was suspended in distilled water. In a sighting test at dose levels of 300 and 2000 mg/kg bw in one animal each, there were no deaths. Due to the absence of mortality, the test substance was orally administered via gavage to four female rats at a dose level at 2000 mg/kg bw. Two animals were found dead during the day of dosing or two days after dosing. One animal was sacrificed for humane reasons, due to the occurrence of clinical signs of toxicity that exceeded the severity limit set forth in the UK Home Office Project Licence, four days after dosing. Overall 3 of 5 females died in the high dose group. Signs of systemic toxicity observed were hunched posture, lethargy, ataxia, pilo-erection, emaciation, labored respiration, decreased respiratory rate and dehydration. Body weights were not changed. At necropsy, haemorrhagic, ulcerated and epithelial sloughing of the gastric mucosa were noted in the animals that died during the study. The animal sacrificed due to humane reasons showed patchy pallor of the liver and gaseous stomach and small and large intestines. No abnormalities were noted at necropsy of surviving animals. Based on the results at the dose level of 2000 mg/kg bw, a dose level of 300 mg/kg bw was investigated in four female rats. There were no deaths and no signs of systemic toxicity. Body weights were not changed and no abnormalities were found at necropsy. Under the conditions of the study, the LD50 value was considered to be > 300 and < 2000 mg/kg bw.

 

In order to assess the acute inhalation toxicity of boron orthophosphate, male and female rats were exposed for four hours using a nose only exposure to a dust atmosphere of the test substance (Griffiths, 2013). According to OECD 436 and under GLP, the mean achieved atmosphere concentration of the test substance was 5.31 mg/L in air. The mass median aerodynamic diameter (MMAD) was determined to be 2.72 µm and the geometric standard deviation was 2.4. No deaths occurred in 3 male and 3 female rats exposed to the mean achieved atmosphere test concentration of 5.31 mg/L four hours. Signs of hunched posture, pilo-erection and red/brown staining around the eyes or snout are commonly seen in animals for short periods on removal from the chamber following 4-hour inhalation studies. Wet fur is commonly recorded both during and for a short period after exposure. These observations are considered to be associated with the restraint procedure and, in isolation, are not indicative of toxicity. In addition to the observations considered to be due to the restraint procedure, increased respiratory rate was noted in all animals during exposure, on removal from the chamber and one hour post-exposure.

One day after exposure, all animals exhibited increased respiratory rate, hunched posture and pilo-erection. Animals recovered to appear normal from Days 7 to 10 post-exposure. Two males and two female animals exhibited bodyweight losses on the first day post-exposure. No macroscopic abnormalities were found at necropsy. Under the conditions of the study, the LC50 value was considered to be > 5.31 mg/L

Justification for classification or non-classification

The available data on acute oral toxicity with boron orthophosphate (CAS 13308-51-5) meet the criteria for classification as Category 4, H302 according to Regulation (EC) No 1272/2008.

The available data on acute inhalation toxicity with boron orthophosphate (CAS 13308-51-5) do not meet the criteria for classification according to Regulation (EC) No 1272/2008, and are therefore conclusive but not sufficient for classification.