Calcium carbonate

Endpoint summary

Description of key information

Bulk calcium carbonate is not considered to be acutely harmful by the oral, dermal or inhalation routes.

Key value for chemical safety assessment

Acute toxicity: via oral route

Link to relevant study records

Reference

Reference 1

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

19 November 2007 to 11 December 2007

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: GLP 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)

Test type:

fixed dose procedure

Limit test:

yes

Specific details on test material used for the study:

Bulk calcium carbonate

Species:

rat

Strain:

Sprague-Dawley

Sex:

female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Charles River (UK) Ltd, Margate, Kent, UK
- Age at study initiation: 8 - 12 weeks
- Weight at study initiation: 205-237 g
- Fasting period before study: overnight prior to dosing
- Housing: suspended polypropylene cages furnished with soft woodflakes and fitted with stainless steel lids.
- Diet: ad libitum (except overnight prior to dosing and 3-4 hours after dosing)
- Water: ad libitum
- Acclimation period: at least 5 days


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 19 to 25 °C
- Humidity (%): 30 to 70%
- Air changes (per hr): At least 15 changes per hour
- Photoperiod (hrs dark / hrs light): 12 hours of continuous artificial light in each 24 hour period.

Route of administration:

oral: gavage

Vehicle:

arachis oil

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 200 mg/mL
- Amount of vehicle (if gavage): 10 mL/kg

Doses:

2000 mg/kg

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: general observations - at 0.5, 1, 2 and 4 hours after dosing then again at least once daily for 14 days; bodyweights were recorded on days 0, 7 and 14.
- Necropsy of survivors performed: yes
- Other examinations performed: clinical signs.

Statistics:

No data

Preliminary study:

The female test animal did not die during the study following a single oral dose of 2000 mg/kg bw. There were no clinical signs during the preliminary study.

Key result

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Sex:

female

Dose descriptor:

LD0

Effect level:

> 2 000 mg/kg bw

Mortality:

No mortalities occurred.

Clinical signs:

other: No clinical signs of systemic toxicity were observed.

Gross pathology:

No adverse effects were observed.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute oral median lethal dose (LD50) of the test material in the female Sprague-Dawley rat was estimated to be > 2000 mg/kg bw

Reference 2

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

supporting study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

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

Qualifier:

no guideline followed

Principles of method if other than guideline:

The study examined whether the bioavailability of calcium carbonate and calcium citrate could be improved by reducing the particle size. Because nanoscale supplements are novel formulas in health foods, the acute toxicity, sub-chronic toxicity (see separate IUCLID entry) and bioavailability (see separate IUCLID entry) needs to be determined in both sexes of mice in advance.
Standard acute toxicological evaluations of the ICR mice were performed in the initial assessment of the effects of nanoscale calcium carbonate internalisation. Micro calcium carbonate and nano calcium carbonate were administered in a single dose by gavage using a gastric intubation tube. The animals were then observed for a period of 7 days.

GLP compliance:

no

Specific details on test material used for the study:

Uncoated nano calcium carbonate

Species:

mouse

Strain:

ICR

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: National Taiwan University Hospital, Taipei, Taiwan
- Age at study initiation: 8-10 weeks
- Fasting period before study: Animals were fasted overnight
- Diet: Pelleted mouse feed available ad libitum
- Water: Reverse osmosis water available ad libitum


ENVIRONMENTAL CONDITIONS
- Temperature (°C): 21-25 °C
- Humidity (%): 30-70%
- Photoperiod (hrs dark / hrs light): 12 h/12 h day/night cycle


Sham surgery (n = 6, SHAM) or bilateral ovariectomy (n = 30, OVX) was performed from a dorsal approach at 6 to 8 week old mice. Surgical removal of the ovaries is a well-represented approach to mimic the postmenopausal condition in mice. In the sham operation, ovaries were exteriorised and then replaced.

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

The test materials were administered in a single dose by gavage using a gastric intubation tube.

Doses:

Vitamin D3 (261 U/ kg bw) plus micro calcium carbonate: 1.3g/kg bw
Vitamin D3 (261 U/ kg bw) plus nano calcium carbonate: 1.3g/kg bw

No. of animals per sex per dose:

8 animals/sex/dose

Control animals:

yes

Details on study design:

On day seven, all the animals were weighed and any signs of toxicity were noted.

Sex:

male/female

Dose descriptor:

other: NOAEL

Effect level:

1 300 mg/kg bw

Mortality:

No mortality was observed.

Clinical signs:

other: Throughout the study, no unusual behaviour or differences between groups were observed (i.e. no laboured breathing, difficulty moving, hunching or unusual interactions with cage mates were observed).

Table 1: Body weight and mortality during the 7-day acute toxicity test

Dose	Sex (n)	Initial body weight (g)	Final body weight (g)	Mortality dead/treated
Control	Male (8) Female (8)	33.2 ± 3.3 32.5 ± 3.7	35.3 ± 3.9 34.2 ± 3.8	0/8 0/8
Micro calcium carbonate (1.3 g/kg bw)	Male (8) Female (8)	33.4 ± 3.2 32.7 ± 3.4	34.9 ± 3.2 34.3 ± 3.6	0/8 0/8
Nano calcium carbonate (1.3 g/kg bw)	Male (8) Female (8)	32.5 ± 3.6 33.1 ± 2.9	33.7 ± 4.1 34.9 ±3.8	0/8 0/8

Data are mean ± SE values

 

Conclusions:

No mortality or unusual behaviour were observed during the course of the study. The NOAEL for both micro calcium carbonate and nano calcium carbonate were reported to be 1.3 g/kg bw.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

Two studies available, both reliable (K=1, K=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:

20 April 2010 to 04 May 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 403 (Acute Inhalation Toxicity)

Deviations:

no

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:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Specific details on test material used for the study:

Bulk calcium carbonate

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: 9 weeks
- Weight at study initiation: Males: 254.7 - 271.5 g; Females: 177.3 - 200.3 g
- Housing: Optimal Hygienic Conditions (OHC) inside a barrier system. Animals were housed in groups of 5 of the same sex in Makrolon® type-IV cages with wire mesh tops and standard softwood bedding including paper enrichment.
- Diet: Pelleted standard Harlan Teklad 2914C rat maintenance diet available ad libitum except during the period when the animals were restrained in exposure tubes.
- Water: Community tap water from Füllinsdorf available ad libitum in water bottles, except during the period when they were restrained in exposure tubes.
- Acclimation period: Seven days under laboratory conditions

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22 ± 3 °C
- Humidity (%): 30 - 70%
- Air changes: 10-15 per hour
- Photoperiod: 12 hour fluorescent light / 12 hour dark cycle

Route of administration:

inhalation: aerosol

Type of inhalation exposure:

nose only

Remarks:

Flow past exposure

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: Inhalation exposure was performed using a flow-past, nose-only exposure system. The inhalation exposure system is located inside a ducted extraction cabinet.
- Exposure chamber volume: Not specified
- Method of holding animals in test chamber: The animals were confined separately in restraint tubes which were positioned radially around the exposure chamber.
- Source and rate of air: The flow of air at each tube was 0.97 L/min, which is sufficient to minimize re-breathing of the test aerosol as it is more than twice the respiratory minute volume of rodents. The actual airflow rate through the exposure chamber was recorded at approximately 30 minute intervals from the start of the inhalation exposure.
- Method of conditioning air: Not specified
- 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: The particle size distribution of the test aerosol was determined three times during exposure using a 7 stage Mercer cascade Impactor. The particle size distribution was measured by gravimetrically analyzing the test item deposited on each stage of the cascade impactor.
Mass Median Aerodynamic Diameters (MMAD) and Geometric Standard Deviations (GSD) were calculated on the basis of the results from the impactor, using Microsoft Excel Software. The target range was 1 to 4 μm for the MMAD and between 1.5 and 3 for the GSD.
- Treatment of exhaust air: The exhaled air is exhausted through the gap near each feed tube out of the exposure chamber.
- Temperature, humidity, pressure etc in air chamber: The oxygen concentration, airflow rate, temperature and relative humidity of the test atmosphere was measured continuously during exposure using a calibrated device. The results were recorded manually and were reported at 30 minute intervals from the start of exposure and additionally at the end of exposure. The oxygen concentration was maintained above 19% during each exposure period.
Mean oxygen concentration: 20.9 vol%, Mean temperature: 22.4 °C; Mean relative humidity: 7.3%

TEST ATMOSPHERE
- Brief description of analytical method used:
Gravimetric determinations of aerosol concentration were performed eight times during exposure. The samples were collected on a Millipore®durapore filter, Type HVLP loaded in a 47 mm inline 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.
Chemical determinations of aerosol concentration were performed eight times during exposure using the filters collected for gravimetric determination. The filters were transferred into appropriate labeled vials, forwarded at ambient temperature the scientist responsible for formulation analysis and stored at room temperature (20 ± 5 °C) until analysis. The samples were analyzed using an AAS method as follows:
Instrument: Perkin-Elmer Model PE 2100 (software 4100) atomic absorption spectrometer
Flame: Acetylene flame/nitrogen(I) oxide
Slit Width: 0.7 nm high
Wavelength: Calcium: 422.7 nm
- Samples taken from breathing zone: yes

TEST ATMOSPHERE
- Particle size distribution: See table; the particle size of the generated aerosol was fairly stable during the whole exposure period.
- MMAD (Mass median aerodynamic diameter) / GSD (Geometric st. dev.): The Mass Median Aerodynamic Diameters (MMAD) obtained from three gravimetric measurements of particle size distribution during the exposure were similar (MMAD between 2.28 μm and 2.89 μm).The MMADs were well within the target range of 1 to 4 μm, thus deposition of the particles can be assumed to have occurred in both the upper and the lower respiratory tract. In addition, the Geometric Standard Deviations (GSD) were within the target range of 1.5 to 3. Hence, the particle size distributions obtained were considered to be appropriate for acute inhalation toxicity testing.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

Atomic absorption spectrometry

Duration of exposure:

4 h

Remarks on duration:

Exposure was interrupted three times for a total of 8 minutes for cleaning purpose. Nevertheless, the animals were exposed for a period of 4 hours as those interruptions were accounted for.

Concentrations:

Target aerosol concentration: 5 mg/L air
Nominal aerosol concentration: 9.4 mg/L air
Mean measured gravimetric aerosol concentration: 3.0 mg/L air
Mean measured chemical aerosol concentration: 3.0 mg/L air

It was not possible to achieve the target concentration of 5 mg/L air as the achieved level was at the technical limit. Therefore, some variations in the aerosol concentrations occurred. The chemical aerosol concentration compared favourably to the gravimetrically determined concentration. This was in accordance with the high purity of the test item.

No. of animals per sex per dose:

5 animals/ sex

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: Observations for viability were recorded once before exposure on the day of exposure (test day 1), three times during exposure, immediately and 1 h after exposure on test day 1 and twice daily during the observation period.
- Necropsy of survivors performed: yes: All animals were necropsied and examined for macroscopic abnormalities.
- Other examinations performed: Clinical signs: Each animal was examined three times during exposure, immediately and 1 h after exposure on test day 1 and once daily during the observation period. Only grossly abnormal signs were detectable during exposure, as the animals were restrained in the exposure tubes; Body weight: The body weight of each animal was recorded on test days 1 (before exposure), 2, 4, 8 and 15 (before necropsy).

Statistics:

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

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 3 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

All animals survived the scheduled observation period.

Clinical signs:

other: Clinical signs consisted of ruffled fur only and were recorded for all animals starting one hour after exposure. This observation was noted for up to a maximum of test day 4. From test day 5 onwards all animals were free of clinical signs.

Body weight:

The body weight of animal No. 1 on test day 1 was considered to be incorrect, probably due to a weighing error. The body weight of this animal from test day 2 onwards was within the range of the other male animals. These animals showed slight body weight loss from test day 1 to test day 2. Marginal to slight body weight loss was also noted in three females from test day 1 to test day 2 and in one female up to test day 4. All these animals showed normal body weight thereafter as well as the remaining female animal.

Gross pathology:

There were no macroscopic findings during this study.

Table 1: Test atmosphere conditions

Recording time (hours:min)		O2 concentration (vol %)		Temperature (° C)		Relative humidity (% RH)
08:10		20.7		22.5		6.4
08:40		20.6		22.5		6.2
09:10		20.7		22.5		6.7
09:45		20.6		22.5		13.8
10:15		20.7		22.5		7.7
10:45		20.7		22.6		6.7
11:15		20.7		22.5		6.2
11:45		20.6		22.3		6.0
12:15		20.7		22.3		6.8
12.18		20.7		22.2		6.8
MEAN		20.6		22.4		7.3
St. Dev.		0.0		0.1		2.3
N		10		10		10

 

 

Table 2: Chemical determination of aerosol concentrations

Sampling time (hours:min)	Sampling volume (L)	Amount of test item on the filter (mg)	Chemical aerosol concentration (mg/L air)
08:25-08:30	5.1	29.49	5.8
09:25 - 09:30	5.1	10.84	2.1
09:44 - 09:48	4.0	5.799	1.4
10:03 - 10:07	4.0	7.885	2.0
10:25 - 10:29	4.0	14.14	3.5
10:56 - 11:00	4.0	11.90	2.9
11:30 - 11:34	4.0	13.11	3.2
11:55 - 11:59	4.0	12.37	3.1
Mean			3.0
St. Dev.			1.3
N			8

 

 

Table 3: Particle size distribution

Time	Total amount collected (µg)	Percentages: Stage No. Effective cut-off diameter (µm)								MMAD (µm)	GSD	Corr. Coeff. (R)	%<4 µm
		1 --	2 4.6	3 3.0	4 2.13	5 1.6	6 1.06	7 0.715	8 0.325
08:36	754	15.4	25.6	27.1	17.4	8.0	3.6	1.1	2.0	2.61	2.11	0.946	71.6
10:32	849	22.0	26.3	19.4	15.4	9.2	3.2	2.5	2.0	2.89	2.37	0.965	64.7
11:37	735	6.9	34.3	25.9	16.2	11.2	2.3	0.3	3.0	2.28	1.94	0.913	80.2

 

Table 4: Body weights

Day	Animal body weight (g)
	1	2	3	4	5
Males
1	140.7a	264.6	271.5	268.9	254.7
2	255.7	252.5	264.7	262.1	243.3
4	264.8	262.2	271.9	270.7	254.7
8	283.3	279.8	282.5	286.3	266.5
15	305.8	300.5	306.1	310.2	282.2
Females
1	200.3	194.0	199.0	177.3	194.9
2	198.6	189.8	195.6	185.6	189.5
4	203.9	197.0	194.7	193.3	197.0
8	214.3	205.7	205.9	196.5	209.5
15	214.6	213.0	221.4	209.3	226.5

a Error undetermined

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The LC50 of Calcium carbonate (CAS: 471-34-1) obtained in this study was estimated to be greater than 3.0 mg/L air (chemically determined mean aerosol concentration). This was the highest technically achievable concentration and in accordance with Regulation (EC) No. 1272/2008 (EU CLP) the substance is not considered to be classified.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating conc.

Value:

3 000 mg/m³ air

Quality of whole database:

One study available, K=1

Acute toxicity: via dermal route

Link to relevant study records

Reference

Endpoint:

acute toxicity: dermal

Type of information:

experimental study

Adequacy of study:

key study

Study period:

06 January 2010 - 20 January 2010

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

guideline study

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Deviations:

no

Qualifier:

according to guideline

Guideline:

EU Method B.3 (Acute Toxicity (Dermal))

Deviations:

no

GLP compliance:

yes (incl. QA statement)

Test type:

standard acute method

Limit test:

yes

Specific details on test material used for the study:

Uncoated nano calcium carbonate

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Source: Harlan Laboratories UK Limited, Bicester, Oxon, UK
- Age at study initiation: 8-12 weeks
- Weight at study initiation: at least 200 g
- Fasting period before study: No data
- Housing: The animals were housed in suspended solid floor polypropylene cages furnished with woodflakes. The animals were housed individually during the 24-hour exposure period and in groups of five, by sex, for the remainder of the study.
- Diet (e.g. ad libitum): Food (2014 Teklad Global Rodent diet) was available ad libitum.
- Water (e.g. ad libitum): Mains drinking 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 fifteen changes per hour
- Photoperiod (hrs dark / hrs light): twelve hours continuous light (06:00 to 18:00) and twelve hours darkness

Type of coverage:

semiocclusive

Vehicle:

arachis oil

Details on dermal exposure:

TEST SITE
- Area of exposure: back and flanks of each animal
- % coverage: approximately 10% of the total body surface area
- Type of wrap if used: A piece of surgical gauze was placed over the treatment area and semi-occluded with a piece of self-adhesive bandage.


REMOVAL OF TEST SUBSTANCE
- Washing (if done): After the 24-hour contact period the bandage was carefully removed and the treated skin and surrounding hair wiped with cotton wool moistened with arachis oil BP to remove any residual test material.
- Time after start of exposure: 24 h


TEST MATERIAL
The appropriate amount of test material, moistened with arachis oil BP, was applied as evenly as possible to an area of shorn skin using a graduated syringe.

Duration of exposure:

24 h

Doses:

2000 mg/kg

No. of animals per sex per dose:

5 animals/ sex/ dose

Control animals:

not specified

Details on study design:

The animals were observed for deaths or overt signs of toxicity 0.5, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days.

After removal of the dressings and subsequently once daily for fourteen days, the test sites were examined for evidence of primary irritation and scored according to the scale from Draize (1977).

Individual bodyweights were recorded prior to application of the test material on Day 0 and on Days 7 and 14.

At the end of the study the animals were killed 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.

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Mortality:

There were no deaths.

Clinical signs:

other: There were no signs of systemic toxicity or dermal irritation.

Gross pathology:

No abnormalities were noted at necropsy.

Table 1: Individual clinical observations and mortality data

Dose level (mg/kg)	Animal no. & sex	Effects noted after initiation of exposure (hours)				Effects noted after initiation of exposure (days)
		0.5	1	2	4	1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	Males (1-1, 1-2, 1-3 & 1-4)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0
	Females (2-1, 2-2, 2-3 & 2-4)	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0	0

0 = no signs of systemic toxicity

 

 

Table 2: Individual dermal reactions – Males

Dose level (mg/kg)	Animal no. & sex	Observation	Effects noted after initiation of exposure (days)
			1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	Males (1-1, 1-2, 1-3 & 1-4)	Erythema	0	0	0	0	0	0	0	0	0	0	0	0	0	0
		Oedema	0	0	0	0	0	0	0	0	0	0	0	0	0	0
		Other	0	0	0	0	0	0	0	0	0	0	0	0	0	0

0 = No reactions

 

 

Table 3: Individual dermal reactions – Females

Dose level (mg/kg)	Animal no. & sex	Observation	Effects noted after initiation of exposure (days)
			1	2	3	4	5	6	7	8	9	10	11	12	13	14
2000	Females (2-1, 2-2, 2-3 & 2-4)	Erythema	0	0	0	0	0	0	0	0	0	0	0	0	0	0
		Oedema	0	0	0	0	0	0	0	0	0	0	0	0	0	0
		Other	0	0	0	0	0	0	0	0	0	0	0	0	0	0

0 = No reactions

 

 

Table 4: Individual bodyweights and weekly bodyweight changes

Dose level (mg/kg)	Animal no. & sex	Bodyweight (g) at Day			Bodyweight change (g) during week
		0	7	14	1	2
2000	1-0 Male	232	256	278	24	22
	1-1 Male	235	255	270	20	15
	1-2 Male	242	268	288	26	20
	1-3 Male	224	246	270	22	24
	1-4 Male	234	261	279	27	18
	2-0 Female	220	228	239	8	11
	2-1 Female	203	204	216	1	12
	2-2 Female	211	216	218	5	2
	2-3 Female	217	220	230	3	10
	2-4 Female	212	213	220	1	7

 

 

Table 5: Individual necropsy findings

Dose level (mg/kg)	Animal no. & sex	Macroscopic observations
2000	Males (1-1, 1-2, 1-3 & 1-4)	No abnormalities detected
	Females (2-1, 2-2, 2-3 & 2-4)	No abnormalities detected

 

 

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The acute dermal median lethal dose (LD50) of the test material in the Wistar strain rat was found to be greater than 2000 mg/kg bodyweight.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

One study available, K=1

Additional information

Acute toxicity - Oral route:

In a reliable GLP study performed to OECD Guideline 420 [Bradshaw 2008] bulk calcium carbonate was administered by gavage at 2,000 mg/kg bw to 5 female rats (Sprague-Dawley). The animals were observed for clinical signs and mortality for 14 days. No mortalities were observed in the observation period and there were no clinical signs of systemic toxicity, adverse changes in bodyweight or macroscopic effects noted at necropsy. The oral LD50 for rats was > 2000 mg/kg bw.

Acute toxicity - Inhalation route:

In a reliable GLP study performed to OECD Guideline 403 [Schuler D, 2010], bulk calcium carbonate was administered by inhalation at a measured concentration of 3 mg/L air to 5 male and 5 female rats (Wistar). The animals were observed for clinical signs and mortality for 14 days and on test day 15, all animals were sacrificed and necropsied.All animals survived the scheduled observation period. Ruffled fur was observed in all animals from the end of the exposure up to test day 4. Thereafter, all animals were free of clinical signs. Transient body weight loss was noted in most animals from test day 1 to test day 2 but normal body weight development was observed in general thereafter. No macroscopic findings were present at necropsy.The inhalation LD50 for rats was > 3 mg/L air. This was the highest technically achievable concentration.

Three different samples of Calcium Carbonate were supplied by the Sponsor: 1). calcium carbonate (nano); 2). calcium carbonate (aragonite form); 3). precipitated calcium carbonate (bulk). Preliminary technical trials were conducted with the above-mentioned samples differing in size (nano versus precipitated) and crystal structure (aragonite versus precipitated).

The original intention was to use the nano form of calcium carbonate because this form was anticipated to represent the worst case as it is likely to be more soluble than the bulk form due to the smaller particle size and hence greater surface area for systemic absorption and passage throughout the lungs. However, the aerosol concentration targeted in this study could only be achieved with precipitated calcium carbonate. Aerosol generation trials with calcium carbonate (nano) and calcium carbonate (aragonite form) resulted in blockage of the aerosol generator. As a result the study was performed with precipitated calcium carbonate (bulk).

Acute toxicity - Dermal route:

In a reliable GLP study performed to OECD Guideline 402 [Bradshaw 2010] uncoated nano calcium carbonate was applied as a paste in arachis oil to the skin of 5 male and 5 female rats (Wistar) at a dose of 2000 mg/kg bw and covered with a semi-occlusive dressing for 24 hours. After completion of the exposure period the skin was wiped with cotton wool moistened with arachis oil to remove any residual test material. There were no deaths or clinical signs of systemic toxicity during the 14 -day observation period. All animals showed expected bodyweight gains over the study period. No abnormalities were noted at necropsy. The LD₅₀was > 2000 mg/kg bw.

The nano form of calcium carbonate was tested because this form was anticipated to represent the worst case as the smaller size particles are more likely to be transported through the skin. However, the results are directly applicable to the bulk form of calcium carbonate.

Justification for classification or non-classification

Oral: The oral LD50 for rats was > 2000 mg/kg bw in an OECD Guideline 420 study. Therefore bulk calcium carbonate does not require classification according to the criteria described in Regulation (EC) No 1272/2008

Inhalation: The inhalation LD50 for rats was > 3 mg/L air in an OECD Guideline 403 study. The result was achieved at the maximum attainable concentration and is considered to be equivalent to a limit test conducted at 5 mg/L. Therefore, bulk calcium carbonate is not considered to be classified according to the criteria described in Regulation (EC) No 1272/2008.

Dermal: The dermal LD50 for rats was > 2000 mg/kg bw in an OECD Guideline 402 study performed using uncoated nano calcium carbonate. This result is read across to the bulk form, therefore bulk calcium carbonate does not require classification according to the criteria described in Regulation (EC) No 1272/2008