Disodium fluorophosphate

Endpoint summary

Description of key information

Acute oral toxicity: Three weight of evidence studies are available for the acute oral toxicity endpoint, all studies are conducted prior to the institution of GLP but are well documented and acceptable for assessment. The studies, Lim (1978) and Shourie (1950) report LD50 values of 710 mg/kg bw and 570 ± 68 mg/ kg bw respectively.The third, Whitford (1990) reports higher values but in the same classification range.  According to Regulation (EC) No 1272/2008 (EU CLP) these results are sufficient to classify the test material for acute toxicity via the oral route (Category 4).
Acute dermal toxicity: Testing was waived on the basis that further in vivo testing is considered to be scientifically unjustified as testing has been performed on the likely route of exposure (inhalation).
Acute inhalation toxicity: A GLP study conducted according to OECD Guideline 403 is available to assess the acute inhalation toxicity of disodium fluorophosphate. The acute inhalation median lethal concentration (LC50) of the test material was found to be greater than the maximum attainable concentration and the study is therefore considered to be equivalent to a limit test conducted at 5mg/ L. In accordance with Regulation EC (No.) 1272/2008 (EU CLP) disodium fluorophosphate will not be classified for acute inhalation toxicity.

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:

weight of evidence

Study period:

no data

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

study well documented, meets generally accepted scientific principles, acceptable for assessment

Qualifier:

according to guideline

Guideline:

other: no data

Deviations:

not applicable

Principles of method if other than guideline:

Forty-five fasted albino rats weighing 200 to 300 grams were given a single dose of from 263 mg/ kg to 1323 mg/ kg of a 5% aqueous solution of the test material. Administration was via stomach tube. The percentage mortality observed in 24 hours was used to predict values for the LD50.

GLP compliance:

no

Remarks:

Study predates GLP

Test type:

fixed dose procedure

Limit test:

yes

Species:

rat

Strain:

not specified

Sex:

not specified

Details on test animals or test system and environmental conditions:

TEST ANIMALS

- Weight at study initiation: 200 - 300 grams
- Fasting period before study: yes, no data on duration

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

no data

Doses:

Single doses of from 263 mg/ kg to 1323 mg/ kg were administered in a 5% aqueous solution.

No. of animals per sex per dose:

Forty-five rats were divided into 9 groups of 5 animals.

Control animals:

not specified

Details on study design:

The percentage mortality observed in 24 hours was recorded.

Statistics:

LD50 values were predicted by graphical analysis.

Preliminary study:

No data.

Sex:

not specified

Dose descriptor:

LD50

Effect level:

570 mg/kg bw

Remarks on result:

other: ± 68 mg/ kg

Mortality:

No data.

Clinical signs:

other: No data.

Gross pathology:

No data.

Other findings:

On the basis of fluoride content the LD50 is 75 mg/ kg bodyweight

No data.

Interpretation of results:

Toxicity Category IV

Remarks:

Migrated information no data Criteria used for interpretation of results: EU

Conclusions:

The LD50 of rats orally gavaged with sodium monofluorophosphate was predicted to 570 ± 68 mg/ kg bodyweight.

This study is considered to be acceptable and to adequately satisfy both the guideline requirement and the regulatory requirement for this endpoint as a key study. In accordance with Regulation (EC) 1272/2008 the test material is considered to be classified for acute toxicity via the oral route (Category 4).

Endpoint conclusion

Endpoint conclusion:

adverse effect observed

Dose descriptor:

LD50

Value:

570 mg/kg bw

Quality of whole database:

The available data are published literature reports and are not performed in accordance with GLP. They have been assigned a Klimisch score of 2.

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:

18 May 2010 - 03 August 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Remarks:

Study conducted in compliance with agreed protocols, with no or minor deviations from standard test guidelines and/or minor methodological deficiencies, which do not affect the quality of the relevant results. This study is conducted according to an appropriate guideline and under the conditions of GLP, the study is therefore considered to be acceptable and to adequately satisfy both the guideline requirement and the regulatory requirement as a key study for this endpoint.

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

yes

Remarks:

Values for relative humidity during husbandry above the target range occasionally occurred, usually following room cleaning, and were considered not to have any influence on the study. Geometric Standard Deviations values marginally above the target range

Qualifier:

according to guideline

Guideline:

EU Method B.2 (Acute Toxicity (Inhalation))

Deviations:

no

Qualifier:

according to guideline

Guideline:

EPA OPPTS 870.1300 (Acute inhalation toxicity)

Deviations:

yes

Remarks:

Values for relative humidity during husbandry above the target range occasionally occurred, usually following room cleaning, and were considered not to have any influence on the study.

GLP compliance:

yes (incl. QA statement)

Remarks:

Date of inspection: 5th to 9th and 26th to 30th November 2007 Date of signature: 30th April 2008

Test type:

standard acute method

Limit test:

yes

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS

- Source:
Harlan Laboratories B.V., Kreuzelweg 53, 5961 NM Horst / Netherlands

- Age at study initiation:
Males: 10 weeks, Females: 10 weeks

- Weight at study initiation:
Males: 256.3 to 316.1 g, Females: 181.5 to 199.0 g

- Fasting period before study:
Not applicable

- Housing:
Animals were housed in groups of 5 of the same sex in Makrolon® type-IV cages with wire mesh tops and standard softwood bedding ("Lignocel" J. Rettenmaier & Söhne GmbH & Co KG, 73494 Rosenberg / Germany, imported by Provimi Kliba AG, 4303 Kaiseraugst / Switzerland) including paper enrichment (Enviro-dri from Lillico, Biotechnology, Surrey, UK).

- Diet (e.g. ad libitum):
Animals had ad libitum access to a pelleted standard Harlan Teklad 2914C rat maintenance diet (Provimi Kliba AG, 4303 Kaiseraugst, Switzerland) batch no. 82/09 except during the period when the animals were restrained in exposure tubes. Results of the analyses for contaminants and their limits of acceptability are archived at Harlan Laboratories Ltd.

- Water (e.g. ad libitum):
Community tap water from Füllinsdorf ad libitum in water bottles, except during the period when they were restrained in exposure tubes. Results of representative analyses for contaminants are archived at Harlan Laboratories Ltd.

- Acclimation period:
Performed under Harlan Laboratories Study B68308 for 14 days under laboratory conditions, after clinical health examination. Only animals without any visible signs of illness were used for the study. A further observation of clinical signs was performed on the day of exposure, before exposure start.

ENVIRONMENTAL CONDITIONS
Optimal Hygienic Conditions (OHC) inside a barrier system. Air-conditioned with 10 - 15 air changes per hour, continuously monitored environment with a temperature range of 22 ± 3 °C, a relative humidity range of 30 - 70% and a 12 hour fluorescent light / 12 hour dark cycle. Values for relative humidity above the range occasionally occurred, usually following room cleaning, and were considered not to have any influence on the study. These data are not reported but retained at Harlan Laboratories Ltd. A radio program was played during most of the light period.

IN-LIFE DATES: From: Day 1 To: Day 14

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Remarks:

flow-past

Vehicle:

clean air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:
A CR3020 rotating brush aerosol generator connected to a micronizing jet mill. The aerosol generated was then discharged into the flow-past, nose-only exposure chamber through a 63Ni charge neutralizer.

- Exposure chamber volume:
Not applicable (nose-only, flow-past inhalation exposure chamber)

- Method of holding animals in test chamber:
The animals were confined separately in restraint tubes which were positioned radially around the flow-past, nose-only exposure chamber. Only the nose of each animal was exposed to the test atmosphere.

- Source of air:
Compressed air was supplied by means of an oil free compressor and passed respiratory quality filters before it was introduced into the exposure system.

- Method of conditioning air:
Respiratory quality filters

- System of generating particulates/aerosols:
A dust aerosol was generated from the test item using a CR3020 rotating brush aerosol generator connected to a micronizing jet mill. The aerosol generated was then discharged into the exposure chamber through a 63Ni charge neutralizer.

- Method of particle size determination:
Mercer Impactor (Model 02-130, In-Tox. Products Inc., Albuquerque, New Mexico, U.S.A.).

- Treatment of exhaust air:
Filtered

- Temperature, humidity, pressure in air chamber:
The oxygen concentration, temperature and relative humidity of the test atmosphere were measured continuously during the exposure on test aerosol samples taken at a representative exposure port using a calibrated device. The results were recorded manually and are reported at 30 minute intervals from the start of exposure.

TEST ATMOSPHERE
- Brief description of analytical method used:
Gravimetric determinations of aerosol concentration were performed six times during exposure. The samples were collected on a Millipore®durapore filter, Type HVLP loaded in a 47 mm in-line stainless steel filter sampling device. The filters were weighed before and immediately after sampling using a calibrated balance. The test aerosol concentration was calculated from the amount of test item present on the filter and the sample volume.

- Samples taken from breathing zone:
yes

VEHICLE
No vehicle used.

Analytical verification of test atmosphere concentrations:

no

Remarks:

Gravimetric only

Duration of exposure:

4 h

Concentrations:

Mean Achieved (mg/L) 2.1
The nominal aerosol concentration was 6.5 mg/L air.
Mean Mass Median Aerodynamic Diameter (µm) 2.89, 2.97, and 2.93
Inhalable Fraction (% <4 µm) 61.7, 60.7, and 60.9%
Geometric Standard Deviation 3.00, 3.01, 3.05

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:
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 fourteen days. Individual bodyweights were recorded prior to treatment on the day of exposure and on Days 2, 4, 8 and 15 or at death.

- Necropsy of survivors performed:
yes

- Other examinations performed:
None

Statistics:

No statistical analysis was performed as only one group was allocated to the study.

Preliminary study:

Not applicable

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 2.1 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Remarks on result:

other: CL not given

Mortality:

All animals survived the scheduled observation period.

Clinical signs:

other: Immediately and two hours after the end of exposure (test day 1), ruffled fur was noted in all animals. In addition, immediately after the end of exposure slight or moderate salivation was observed in two males and 5 females. From test day 2 onwards, unti

Body weight:

From test day 1 to test day 2, slight to moderate body weight loss was noted in all animals. Thereafter all animals gained weight until scheduled necropsy.

Gross pathology:

There were no macroscopic findings.

Other findings:

Not applicable.

The nominal aerosol concentration was 6.5 mg/L air.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The LC50 of disodium fluorophosphate obtained in this study was estimated to be greater than 2.1 mg/L air (gravimetrically determined mean aerosol concentration). This was the highest technically achievable concentration. There was no indication of relevant sex-related differences in toxicity of the test item. There were no animal mortalities during the observation period.

This study is conducted according to an appropriate guideline and under the conditions of GLP, the study is therefore considered to be acceptable and to adequately satisfy both the guideline requirement and the regulatory requirement as a key study for this endpoint.

Executive summary:

A group of five male and five female albino rats [RccHan^TM:WIST(SPF)] was exposed by nose-only, flow-past inhalation for four hours to the test item atagravimetricallydetermined mean concentration of 2.1 mg/L air.All animals were observed for clinical signs and mortality during the inhalation exposure and the subsequent 14-dayobservation period. Body weights were recorded prior to exposure on test day 1, and during the observation period on test days 2, 4, 8 and 15 before necropsy. On test day 15 all animals were sacrificed and necropsied.

 

The ranges of aerosol concentration, temperature, relative humidity, oxygen content and airflow rate measured during the exposure were considered to be satisfactory for a study of this type. In addition, the test item was considered to be respirable to rats.

 

All animals survived the scheduled observation period.

 

Clinical signs were limited to the day of exposure and consisted of ruffled fur in all and salivation in most animals.

 

From test day 1 to test day 2, transient body weight loss was noted in all animals. Body weight gain was observed thereafter.

 

No macroscopic findings were recorded.

 

In conclusion, the LC₅₀ofDisodium monofluoro phosphateobtained in this study was estimated to be greater than 2.1 mg/Lair (gravimetrically determined mean aerosol concentration). This concentration was at the technical limit with a respirable particle size.There was no indication of relevant sex-related differences in toxicity of the test item.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

LC50

Value:

2 100 mg/m³ air

Quality of whole database:

The study is compliant with GLP and has a Klimisch score of 1.

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Quality of whole database:

No data available. A second acute study is provided on the likely route of exposure (inhalation).

Additional information

Acute oral toxicity: The LD50 value reported by Shourie(1950) is to be used for the purposes of risk assessment. Shourie(1950) is comparable to the modern day guideline OECD 401, most notably because the study was conducted using rats rather than mice, as in Lim (1978). In addition to this, a wide range of doses were used in Shourie(1950) therefore generating more meaningful results which will provide a value closer to the true LD50. Finally, the value obtained in Shourie(1950) is a lower value and therefore represents a worst case scenario.

Acute dermal toxicity:

The standard testing regime, as defined in Regulation (EC) No. 1907/2006 has been adapted on the following basis:

In accordance with Annex VIII, Section 8.5.3, Column 2 of regulation (EC) No. 1907/2006 (REACH) testing by the dermal route is appropriate if :

1.      Inhalation of the substance is unlikely; and

2.      skin contact in production and/or use is likely; and

3.      the physicochemical and toxicological suggest a potential for a significant rate of absorption through the skin.

Although skin contact is likely during production and use of disodium fluorophosphate, inhalation of the substance is also likely and as such an acute inhalation study has been performed. As disodium fluorophosphate is an inorganic chemical with a molecular weight of >100 systemic absorption via the dermal route is unlikely and as such inhalation and oral routes are considered to be a worst-case for systemic absorption. In addition, no signs of systemic toxicity were observed in the acute skin and eye studies conducted on disodium fluorophosphate and therefore it can be reliably assumed that a full characterisation of the acute systemic toxicity profile of disodium fluorophosphate can be derived from the acute oral and inhalation studies and as such further in vivo testing would be unethical and could not be scientifically justified.

Justification for selection of acute toxicity – oral endpoint
Three studies are available. This study is selected as it provides the worst-case value.

Justification for selection of acute toxicity – inhalation endpoint
Only one study available.

Justification for classification or non-classification

Acute oral toxicity: Disodium fluorophosphate is considered to be classified for acute oral toxicity (Category 4) in accordance with Regulation (EC) No. 1272/2008 (EU CLP). The weight of evidence reports values for the LD50 of 570 - 1125.38 mg/kg bw. All values lie within the classification range for Category 4 and are sufficient for classification. No further testing is deemed scientifically justified.

Acute inhalation toxicity: Disodium fluorophosphate is not considered to be classified for acute inhalation toxicity in accordance with Regulation (EC) No. 1272/2008 (EU CLP).The key study is considered to be adequate and reliable for the purposes of classification and therefore further in vivo testing is not considered to be scientifically justified.

Acute dermal toxicity: Disodium fluorophosphate is not considered to be classified for acute dermal toxicity in accordance with Regulation (EC) No. 1272/2008 (EU CLP). A toxicologist's expert report is considered to be adequate and reliable for the purposes of classification and therefore further in vivo testing is not considered to be scientifically justified.