Calcium dihydroxide precipitated with carbon dioxide during sugar juice purification

Endpoint summary

Description of key information

SFL 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

Endpoint:

acute toxicity: oral

Type of information:

experimental study

Adequacy of study:

key study

Study period:

7 February - 28 February 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study conducted under GLP

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

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 Ltd., Oxon, UK
- Age at study initiation: 8-12 weeks
- Weight at study initiation: 159-169 g
- Fasting period before study: overnight fast
- Housing: housed in groupd of up to four in suspended solid floor polypropylene cages furnished with woodflakes.
- Diet: ad libitum apart from fast period before dosing and 3-4 hours after dosing. Fed 2014C Teklad Global Rodent diet supplied by Harlan Laboratories UK Ltd., Oxon, UK
- Water: Mains drinkin gwater ad libitum
- Acclimation period: at least five days

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

IN-LIFE DATES: From: To:7/02/2013-28/02/2013

Route of administration:

oral: gavage

Vehicle:

water

Details on oral exposure:

VEHICLE
- Concentration in vehicle: 286.3 mg test substance/mL (animal #1) 289.9 mg test substance/mL (animals #2-5)
- Justification for choice of vehicle: Substance already contains around 30 % w/w water

MAXIMUM DOSE VOLUME APPLIED: 10 mL/kg

DOSAGE PREPARATION (if unusual):

CLASS METHOD (if applicable)
- Rationale for the selection of the starting dose: Based on available toxicity information

Doses:

Animal #1: 2863 mg/kg (equivalent to 1976 mg a.i./kg bw)
Animals # 2-5: 2899 mg/kg bw (equivalent to 2000 mg a.i./kg bw)

No. of animals per sex per dose:

5 females

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: clinical observations 0.5, 1, 2, 4 hours after dosing then daily for 14 days. Body weights day 0, 7 and 14.
- Necropsy of survivors performed: yes
- Other examinations performed: no

Statistics:

Not required

Preliminary study:

No effects seen at 1976 mg ai/kg bw.

Sex:

female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

act. ingr.

Mortality:

There were no deaths.

Clinical signs:

other: No signs of systemic toxicity were noted during the observation period.

Gross pathology:

No abnormalities were noted at necropsy.

Other findings:

Not applicable

Individual Body Weights and Body Weight Changes

 

Dose Level mg/kg	Animal Number and Sex	Body Weight (g) at Day			Body Weight Gain (g) During Week
		0	7	14	1	2
2000*	1-0 Female	162	180	204	18	24
	2-0 Female	159	172	183	13	11
	2-1 Female	165	180	192	15	12
	2-2 Female	168	183	196	15	13
	2-3 Female	169	202	215	33	13

*1976 mg a.i./kg bw for animal 1-0.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

The LD50 (rat) > 2000 mg a.i./kg bw.

Executive summary:

Five female rats were dosed by gavage with 2000 mg a.i./kg bw SFL in a GLP study performed according to OECD 420. There were no deaths and no signs of systemic toxicity were noted during the 14 day observation period. No abnormalities were noted at necropsy. The LD50 (rat) was estimated to be > 2000 mg a.i./kg bw.

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

High - one K=1 study available on the substance itself and a further K=2 study (reliability adjusted because of read across) is available for calcium carbonate, the main constituent of SFL.

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:

29 January - 18 February 2013

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: This summary is based on an unaudited draft report. The summary and reliability will be updated once the final report is available, however it is expected to be reliability 1 as it is a Guideline study performed under GLP.

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

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
- 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:
- Housing: Housed in groups of up to three by sex. Solid floor polypropylene cages/stainless steel lids/softwood flakes/ wooden chew blocks and cardboard 'fun tunnels' for enrichment.
- Diet: ad libitum except during exposure period
- Water: ad libitum except during exposure period. Harlan 2014C Rodent Diet, Harlan Laboratories UK Ltd, Oxon, UK
- Acclimation period: At least 5 days

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

IN-LIFE DATES: From: To: 29/01/13-18/02/13

Route of administration:

inhalation: dust

Type of inhalation exposure:

nose only

Vehicle:

clean air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: SAG 410 Solid Aerosol Generator (TOPAS GmbH, Dresden, Germany)
- Exposure chamber volume: 30 L approximately
- Method of holding animals in test chamber: Tapered polycarbonate retraining tube
- Source and rate of air: Compressed air from an oil free compressor/ 60 L/min
- Method of conditioning air: Passed through a water trap and respiratory quality filters before it was introduced to the SAG 410.
- System of generating particulates/aerosols: The test item concentration within the chamber was controlled by adjusting the test item feed rate from the SAG 410.
- 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 (7.8, 5.8, 3.6, 1.4, 0.74 and 0.34 µm cut points) with stainless steel collection substrates and a back up glass fiber filter, housed in an aluminum 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 7.8, 5.8, 3.6, 1.4, 0.74 and 0.34 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.
- Treatment of exhaust air: The extract from the exposure chamber passed through a ‘scrubber’ trap and was connected with a high efficiency filter to a metered exhaust system
- Temperature, humidity, pressure in air chamber:

TEST ATMOSPHERE
- Brief description of analytical method used: The actual chamber concentration was measured at regular intervals during the exposure period. The gravimetric method used glass fiber 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 was 219% of the actual mean achieved atmosphere concentration and shows that keeping the aerosol airborne was relatively straightforward. See Table 1

- Samples taken from breathing zone: yes

TEST ATMOSPHERE
- See Tables 2, 3 & 4

CLASS METHOD (if applicable)
- Rationale for the selection of the starting concentration: Based on data from read-across substance (calcium carbonate)

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

5.09 mg/L

No. of animals per sex per dose:

3 male/ 3 female

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. Individual body weights 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
- Other examinations performed: clinical signs, body weight. 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.

Sex:

male/female

Dose descriptor:

LC50

Effect level:

> 5.09 mg/L air (analytical)

Based on:

test mat.

Exp. duration:

4 h

Mortality:

There were no deaths during the study

Clinical signs:

other: Common abnormalities noted during the study included increased respiratory rate, hunched posture, pilo-erection and wet fur. Occasional instances of red/brown staining around the snout were also noted. Animals recovered to appear normal from Days 7 to 9

Body weight:

All animals exhibited body weight losses or showed no bodyweight gain on the first day post-exposure. Reasonable body weight gains were noted for all male animals during the remainder of the recovery period. In contrast, all female animals exhibited bodyweight losses from Days 1 to 3, two of these animals also showed no bodyweight gain from Days 3 to 7. Reasonable bodyweight gains were noted in all females during the final week of recovery.

Gross pathology:

No macroscopic abnormalities were detected amongst animals at necropsy.

Interpretation of results:

not classified

Remarks:

Migrated information Criteria used for interpretation of results: EU

Executive summary:

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 Sugar Factory Lime (Dry), in the RccHan^TM: WIST strain rat, was greater than 5.09 mg/L

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating conc.

Value:

5 090 mg/m³ air

Quality of whole database:

High. k=2 study available on the substance itself and k=2 study available on read across substance calcium carbonate, the main constituent of SFL.

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:

13 February - 07 March 2013

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

other: Guideline study performed under GLP

Qualifier:

according to guideline

Guideline:

OECD Guideline 402 (Acute Dermal Toxicity)

Qualifier:

according to guideline

Guideline:

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

GLP compliance:

yes (incl. QA statement)

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 UK Ltd., Oxon, UK.
- Age at study initiation: 8-12 weeks
- Weight at study initiation: males 246-289 g; females 206-228 g
- Fasting period before study:
- Housing: 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: ad libitum 2014C Teklad Global Rodent diet supplied by Harlan Laboratories UK Ltd., Oxon, UK
- Water: ad libitum mains drinking water
- Acclimation period: 5 days minimum

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

IN-LIFE DATES: From: To: 13/02/2013 - 07/03/2013

Type of coverage:

semiocclusive

Vehicle:

water

Details on dermal exposure:

TEST SITE
- Area of exposure: back and flanks
- % coverage: approximately 10%
- 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): wiped with damp cotton wool
- Time after start of exposure: 24 h

TEST MATERIAL
- Amount(s) applied (volume or weight with unit): Equivalent to 2000 mg a.i./kg
- For solids, paste formed: test material was moistened with water

Duration of exposure:

24 h

Doses:

2899 mg/kg (equivalent to 2000 mg a.i./kg body weight)

No. of animals per sex per dose:

5/sex/dose

Control animals:

no

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: The animals were observed for deaths or overt signs of toxicity ½, 1, 2 and 4 hours after dosing and subsequently once daily for fourteen days. Individual body weights were recorded prior to application of the test item on Day 0 and on Days 7 and 14.
- Necropsy of survivors performed: yes
- Other examinations performed: Dermal irritation (on removal of the patch and once daily thereafter)

Statistics:

Not applicable

Sex:

male/female

Dose descriptor:

LD50

Effect level:

> 2 000 mg/kg bw

Based on:

act. ingr.

Mortality:

There were no deaths.

Clinical signs:

other: No signs of systemic toxicity were noted during the observation period.

Gross pathology:

No abnormalities were noted at necropsy.

Other findings:

Dermal irritation:
Brown coloured staining, not preventing evaluation of skin responses, was noted at the test sites of all animals one day after dosing.
There were no signs of dermal irritation.

Individual Body Weights and Body Weight Changes

 

Dose Level mg a.i./kg	Animal Number and Sex	Body Weight (g) at Day			Body Weight Gain (g) During Week
		0	7	14	1	2
2000	1-0 Male	263	279	300	16	21
	1-1 Male	289	309	342	20	33
	1-2 Male	247	255	272	8	17
	1-3 Male	265	285	309	20	24
	1-4 Male	246	255	276	9	21
	2-0 Female	224	223	232	-1	9
	2-1 Female	211	211	215	0	4
	2-2 Female	215	216	221	1	5
	2-3 Female	206	210	217	4	7
	2-4 Female	228	223	239	-5	16

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 item in the Wistar strain rat was found to be greater than 2899 mg/kg body weight (equivalent to 2000 mg active ingredient/kg body weight).

Executive summary:

In a GLP study performed according to OECD TG 402 a group of ten animals (five males and five females) was given a single, 24 hour, semi-occluded dermal application of the test item to intact skin at a dose level of 2899 mg/kg body weight (equivalent to 2000 mg active ingredient/kg body weight). Clinical signs and body weight development were monitored during the study. All animals were subjected to gross necropsy. There were no deaths, signs of systemic toxicity or dermal irritation. Animals showed expected gains in body weight except for three females which showed bodyweight loss or no gain in body weight during the first week with expected gain in bodyweight during the second week. No abnormalities were noted at necropsy. The acute dermal median lethal dose (LD50) of the test item in the Wistar strain rat was found to be greater than 2899 mg/kg body weight (equivalent to 2000 mg active ingredient/kg body weight).

Endpoint conclusion

Endpoint conclusion:

no adverse effect observed

Dose descriptor:

discriminating dose

Value:

2 000 mg/kg bw

Quality of whole database:

High - one K=1 study available on the substance itself and a further K=2 study (reliability adjusted because of read across) is available for calcium carbonate, the main constituent of SFL.

Additional information

Acute toxicity - Oral route:

In a reliable GLP study performed according to OECD TG 420 [Harlan Laboratories (2013a)] Sugar Factory Lime (SFL) was administered by gavage at 2899 mg/kg bw (equivalent to 2000 mg a.i./kg bw)to 5 female rats (Wistar). 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 or adverse changes in bodyweight. No macroscopic effects were noted at necropsy. The oral LD50 for rats was > 2000 mg a.i./kg bw.

The findings of this study are supported by the results of a study performed using calcium carbonate, the major constituent of SFL [Bradshaw J (2008)]. In this study, performed according to OECD TG 420 under GLP, the LD50 for female Sprague-Dawley rats was > 2000 mg/kg bw.

Acute toxicity - Dermal route:

In a reliable GLP study performed according to OECD TG 402 [Harlan Laboratories (2013d)] a group of ten Wistar rats (five males and five females) was given a single, 24 hour, semi-occluded dermal application of Sugar Factory Lime (SFL) to intact skin at a dose level of 2899 mg/kg bw (equivalent to 2000 mg a.i./kg bw). Clinical signs and body weight development were monitored during the study. All animals were subjected to gross necropsy. There were no deaths, signs of systemic toxicity or dermal irritation. Animals showed expected gains in body weight except for three females which showed bodyweight loss or no gain in body weight during the first week with expected gain in bodyweight during the second week. No abnormalities were noted at necropsy. The dermal LD50 for rats was > 2000 mg a.i./kg bw).

The findings of this study are supported by the results of a study performed using a nano- form of calcium carbonate, the major constituent of SFL [Bradshaw (2010a)]. In this study, performed according to OECD TG 402 under GLP, the LD50 for female Sprague-Dawley rats was > 2000 mg/kg bw.

Acute toxicity - Inhalation route:

Sugar Factory Lime (SFL) as manufactured and supplied contains approximately 30 %w/w of water. Although it remains as a powder in this form, it is damp and non-free-flowing. A preliminary study was performed to investigate whether it was possible to generate a stable dust atmosphere from the SFL in this form [Harlan Laboratories Ltd (2013c)]. In order to reduce the particle size of the test item and facilitate aerolisation, the test item was first ground using a Lloytron mini grinder prior to use. Attempts were then made to generate stable dust atmosphere using either a SAG410 Solid Aerosol Generator or a Wright’s Dust Feed. These pieces of equipment have been employed for many years at the laboratory and have proven themselves to be very effective at generating test atmospheres that are suitable for use in this type of study. However, in both cases the test item caused the test item to block and stall extremely quickly and a stable atmosphere could not be generated. It is concluded based on this experiment that, due to the physical nature of SFL as manufactured and supplied and its apparent low volatility, it is considered unlikely to represent a significant hazard by the inhalation route.

In order to investigate the intrinsic properties of the substance, a sample of SFL was dried until the water content was approximately 2.14 % w/w. A preliminary investigation demonstrated that a stable aerosol could be generated using this substance and a full study was undertaken. In this study, performed to OECD TG 436 under GLP, a group of six RccHan™ : WIST strain rats (three males and three females) was exposed to an atmosphere of SFL at 5.09 mg/L [Harlan Laboratories Ltd (2013b)]. The animals were exposed for four hours using a nose only exposure system.The animals were observed for clinical signs and mortality for 14 days and on test day 15 all animals were sacrificed and necropsied.There were no deaths during the study. Common abnormalities noted during the study included increased respiratory rate, hunched posture, pilo-erection and wet fur. Occasional instances of red/brown staining around the snout were also noted. Animals recovered to appear normal from days 7 to 9 post-exposure. All animals exhibited body weight losses or showed no bodyweight gain on the first day post-exposure. Reasonable body weight gains were noted for all male animals during the remainder of the recovery period. In contrast, all female animals exhibited bodyweight losses from Days 1 to 3, two of these animals also showed no bodyweight gain from Days 3 to 7. Reasonable bodyweight gains were noted in all females during the final week of recovery. No macroscopic abnormalities were detected amongst animals at necropsy.The inhalation LC50 for rats was > 5.09 mg/L air.

In a supporting study, performed to OECD TG 403 under GLP calcium carbonate, the major constituent of SFL,was administered by inhalation at a measured concentration of 3 mg/L air to 5 male and 5 female rats (Wistar) [Schuler D (2010)]. 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 LC50 for rats was > 3 mg/L air. This was the highest technically achievable concentration.

Justification for selection of acute toxicity – oral endpoint
Study performed on the substance itself

Justification for selection of acute toxicity – inhalation endpoint
Study performed on the substance itself

Justification for selection of acute toxicity – dermal endpoint
Study performed on the substance itself

Justification for classification or non-classification

Oral: The oral LD50 for rats was > 2000 mg/kg bw in an OECD Guideline 420 study performed using SFL. Therefore Sugar Factory Lime does not require classification 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 SFL. Therefore the substance does not require classification according to the criteria described in Regulation (EC) No 1272/2008.

Inhalation: The inhalation LC50 for rats was > 5.09 mg/L air in an OECD Guideline 436 study performed using SFL. Therefore, Sugar Factory Lime is not considered to be classified according to the criteria described in Regulation (EC) No 1272/2008.