Trisodium trimetaphosphate

Endpoint summary

Description of key information

Acute oral toxicity: Three studies are available for the acute oral toxicity endpoint. All studies indicate that trisodium trimetaphosphate has a low potential for systemic toxicity following acute administration via the oral route. 
The key study (Bradshaw J, 2010) has been conducted to a current guideline (OECD 420) and according to GLP. The acute oral median dose (LD50) of trisodium trimetaphosphate in the female Wistar strain rat was estimated to be greater than 2000 mg/kg bw and is therefore not classified according to Regulation (EC) No 1272/2008 (EU CLP). This conclusion is supported by the additional data provided for this endpoint.
Acute inhalation toxicity: One key study exists. The study (Griffiths D, 2012) is conducted under the conditions of GLP and in accordance with an appropriate guideline (OECD 436). This study has been assigned a Klimisch reliability of 1. The LC50 of trisodium trimetaphosphate in male and female Wistar strain rat was found to be > 5.09 mg/L (maximum attainable concentration) and is therefore not classified according to Regulation (EC) No 1272/2008 (EU CLP).

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:

The study was performed between 26 November 2009 and 15 December 2009

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:

Date of GLP inspection: 01 April 2010 Date of Signature on GLP certificate: 26 November 2009

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 UK Limited, Bicester, Oxon, UK.

- Age at study initiation:
At the start of the study the animals were eight to twelve weeks of age.

- 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 (e.g. ad libitum):
(2014 Teklad Global Rodent diet supplied by Harlan Teklad, Blackthorn, Bicester, Oxon, UK) was allowed ad libitum throughout the study.

- Water (e.g. ad libitum):free access to mains drinking water

- Acclimation period:acclimatisation period of at least five days


ENVIRONMENTAL CONDITIONS
- Temperature (°C):
19 to 25°C

- Humidity (%):
30 to 70%

- Air changes (per hr):
The rate of air exchange was at least fifteen changes per hour.

- Photoperiod (hrs dark / hrs light):
lighting was controlled by a time switch to give twelve hours continuous light (06:00 to 18:00) and twelve hours darkness.


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

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle:
For the purpose of the study the test material was freshly prepared, as required, as a suspension in distilled water to give a dose level of 2000mg/kg bodyweight.

- Amount of vehicle (if gavage):
Not stated

- Justification for choice of vehicle:
Distilled water was the preferred vehicle of the test method.

- Lot/batch no. (if required):
Not stated

- Purity:
Not stated


MAXIMUM DOSE VOLUME APPLIED:
10ml/kg


DOSAGE PREPARATION (if unusual):
Not applicable

CLASS METHOD (if applicable)

- Rationale for the selection of the starting dose:
Using available information on the toxicity of the test material, 2000 mg/kg was chosen as the starting dose.

Doses:

Following a sighting test at a dose level of 2000 mg/kg, an additional four fasted female animals were given a single oral dose of test material, as a solution in distilled water, at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

No. of animals per sex per dose:

1 female at 2000 mg/kg
4 females at 2000 mg/kg

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 then daily for fourteen 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

- Other examinations performed:
Clinical signs, body weight.

Preliminary study:

A sighting test at a dose level of 2000 mg/kg was performed.

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

test mat.

Remarks on result:

other: 95% confidence limits not given in study report.

Mortality:

There were no deaths.

Clinical signs:

other: There were no signs of systemic toxicity.

Gross pathology:

No abnormalities were noted at necropsy.

Table1              Individual Clinical Observations and Mortality Data

Dose Level mg/kg	Animal Number and Sex	Effects Noted After Dosing (Hours)				Effects Noted During Period After Dosing (Days)
		½	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	1-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-0 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-1 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-2 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	2-3 Female	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

 

Table2              Individual Bodyweights and Bodyweight Changes

Dose Level mg/kg	Animal Number and Sex	Bodyweight (g) at Day			Bodyweight Gain (g) During Week
		0	7	14	1	2
2000	1-0 Female	196	201	202	5	1
	2-0 Female	170	181	197	11	16
	2-1 Female	184	199	209	15	10
	2-2 Female	169	182	183	13	1
	2-3 Female	178	181	185	3	4

 

Table3              Individual Necropsy Findings

Dose Level mg/kg	Animal Number and Sex	Time of Death	Macroscopic Observations
2000	1-0 Female	Killed Day 14	No abnormalities detected
	2-0 Female	Killed Day 14	No abnormalities detected
	2-1 Female	Killed Day 14	No abnormalities detected
	2-2 Female	Killed Day 14	No abnormalities detected
	2-3 Female	Killed Day 14	No abnormalities detected

0= No signs of systemic toxicity

Interpretation of results:

GHS criteria not met

Conclusions:

The acute oral median lethal dose (LD50) of the test material in the female Wistar strain rat was estimated to be greater than 2000 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. In addition, this study is sufficient for the classification and labelling of trisodium trimetaphosphate in accordance with Regulation (EC) No. 1272/2008 (EU CLP).

Executive summary:

Introduction. 

The study was performed to assess the acute oral toxicity of the test material in the Wistar strain rat. The method was designed to meet the requirements of the following:

OECD Guidelines for Testing of Chemicals No 420 “Acute Oral Toxicity - Fixed Dose Method” (adopted 17 December 2001)

Method B1 bis Acute Toxicity (Oral) of Commission Regulation (EC) No. 440/2008

Method. 

Following a sighting test at a dose level of 2000 mg/kg, an additional four fasted female animals were given a single oral dose of test material, as a suspension in distilled water, at a dose level of 2000 mg/kg bodyweight. Clinical signs and bodyweight development were monitored during the study. All animals were subjected to gross necropsy.

Mortality. 

There were no deaths.

Clinical Observations. 

There were no signs of systemic toxicity.

Bodyweight. 

All animals showed expected gains in bodyweight.

Necropsy. 

No abnormalities were noted at necropsy.

Conclusion. 

The acute oral median lethal dose (LD₅₀) of the test material in the female Wistar strain rat was estimated to be greater than 2000 mg/kg bodyweight (Globally Harmonised Classification System-Unclassified).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

LD50 >2000 mg/kg bw
The study is conducted under the conditions of GLP and in accordance with an appropriate guideline (OECD 420). This study has been assigned a Klimisch reliability of 1. The supporting data are not considered to be sufficient for use as stand-alone information but are sufficient to support the conclusions drawn from the key study. The database is considered to be of high quality.

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

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:

Date of Inspection: 19-21 July 2011, Date of signature: 31 August 2011

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
- Fasting period before study: none
- 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 (e.g. ad libitum): with the exception of the exposure period diet (Harlan 2014C Rodent Diet, Harlan Laboratories UK Ltd, Oxon, UK) was available ad libitum
- Water (e.g. ad libitum): with the exception of the exposure period water was available ad libitum.
- Acclimation period: At least 5 days

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

IN-LIFE DATES: From: To:

Route of administration:

inhalation: aerosol

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. See 'exposure apparatus' for further details.
- 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 (9.7, 6.7, 3.8, 1.8, 0.94 and 0.46 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 9.7, 6.7, 3.8, 1.8, 0.94 and 0.46 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. Individual values are given in Attachment 1.
-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. Individual values are given in Attachment 2.

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 D 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 356% of the actual mean achieved atmosphere concentration and shows that keeping the aerosol airborne was moderately difficult.

VEHICLE
- Composition of vehicle (if applicable):
- Concentration of test material in vehicle (if applicable):
- Justification of choice of vehicle:
- Lot/batch no. (if required):
- Purity:

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution:
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.):

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration:

Analytical verification of test atmosphere concentrations:

no

Duration of exposure:

4 h

Concentrations:

5.09 mg/L (target concentration 5 mg/L)

No. of animals per sex per dose:

3 males, 3 females

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 killed 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:

> 5.09 mg/L air

Based on:

test mat.

Exp. duration:

4 h

Mortality:

There was no mortality.

Clinical signs:

other: Individual clinical observations are given in Attachment 5. Signs of hunched posture and pilo-erection 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

Body weight:

Individual bodyweights, together with bodyweight changes, are given in Attachment 6.
Two males and all female animals exhibited bodyweight losses or showed no bodyweight gains on the first day post-exposure. All animals exhibited reasonable bodyweight gains during the remainder of the recovery period.

Gross pathology:

Individual necropsy findings are given in Appendix 7.
With the exception of one instance of dark patches on the lungs, no macroscopic abnormalities were detected amongst animals at necropsy.

It is noted that the mean mass median aerodynamic diameter (MMAD) exceeds the range given in test guidelines (1-4 μm). This deviation is due to the physical characteristics of the test item. During the characterisation phase of the study various techniques were employed in order to try and reduce the achievable MMAD, these included grinding the test item in a planetary ball mill and adding particle separation devices into the generation system in order to try and remove larger particles. During the characterisation phase of the study the test atmosphere concentration was reduced to 2 mg/L in an attempt to achieve a particle size as close to 4 μm as possible. This did reduce the particle size slightly but it wasn’t considered to be significant. It was, therefore, preferable to expose the animals to a higher concentration of test item, even though this also increased the MMAD, as this resulted in the animals being exposed to the highest possible concentration of particles.

Interpretation of results:

GHS criteria not met

Conclusions:

No deaths occurred in a group of six rats exposed to a mean achieved atmosphere concentration of 5.09 mg/L for four hours. It was therefore considered that the acute inhalation median lethal concentration (4 hr LC50) of trisodium trimetaphosphate, in the RccHanTM : WIST strain rat, was greater than 5.09 mg/L (Globally Harmonised Classification System – unclassified).
This study is considered to be acceptable for use as a key study in accordance with Regulation (EC) No. 1907/2006 (REACH) and for classification and labelling in accordance with Regulation (EC) No. 1272/2008 (EU CLP). Further testing is scientifically unjustified.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Quality of whole database:

LC50 >5090 mg/m3
The study is conducted under the conditions of GLP and in accordance with an appropriate guideline (OECD 436). This study has been assigned a Klimisch reliability of 1. The database is considered to be of high quality.

Acute toxicity: via dermal route

Endpoint conclusion

Endpoint conclusion:

no study available

Additional information

Acute dermal toxicity: adaptation

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 trisodium trimetaphosphate, inhalation of the substance is also likely and as such an acute inhalation study is available.

Furthermore, according to Annex VIII, Section 8.5.3, Column 2 of REACH, testing by the dermal route is not appropriate when the physicochemical and toxicological properties suggest that the rate of absorption through the skin will not occur at a significant rate.

The molecular weight of the substance is >100, this makes dermal absorption unlikely *. In addition, the very high water solubility of 265 g/l suggests that the substance is too hydrophilic to cross the lipid rich environment of the striatum corneum. Taken together these properties suggest that dermal uptake will be minimal.

 

Further, the studies conducted to assess the potential for acute oral and inhalation toxicity concluded that trisodium trimetaphosphate is not classified in accordance with Regulation (EC) No. 1272/2008 (EU CLP). As it is considered likely that absorption via the oral or inhalation routes will be greater than total systemic absorption via the dermal route, it can be concluded that trisodium trimetaphosphate will not be classified for acute dermal toxicity. Further in vivo testing is therefore considered to be scientifically unjustified.

 

*According to the ECHA Guidance on Information Requirements and Chemical Safety Assessment; Chapter R.7c: Endpoint Specific Guidance.

Justification for classification or non-classification

Trisodium trimetaphosphate is not considered to be classified for acute toxicity via any route. The data provided for this endpoint are considered to be conclusive and no further investigation is required.