Registration Dossier

Toxicological information

Acute Toxicity: inhalation

Currently viewing:

Administrative data

Endpoint:
acute toxicity: inhalation
Type of information:
experimental study
Adequacy of study:
key study
Study period:
26 March 2010 to 20 April 2010.
Reliability:
1 (reliable without restriction)
Rationale for reliability incl. deficiencies:
other: 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.

Data source

Reference
Reference Type:
study report
Title:
Unnamed
Year:
2010
Report Date:
2010

Materials and methods

Test guidelineopen allclose all
Qualifier:
according to
Guideline:
OECD Guideline 403 (Acute Inhalation Toxicity)
Deviations:
no
Qualifier:
according to
Guideline:
EU Method B.2 (Acute Toxicity (Inhalation))
Deviations:
no
GLP compliance:
yes (incl. certificate)
Remarks:
Date of GLP inspection: 15/09/2009. Date of signature on GLP certificate: 26/11/2009
Test type:
standard acute method
Limit test:
yes

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
Sponsor's identification: MnSO4.H2O
Description : Extremely pale pink powder
Batch number : 08729
Date received : 08 September 2008
Storage conditions: Room temperature, in the dark

Test animals

Species:
rat
Strain:
Wistar
Sex:
male/female
Details on test animals and environmental conditions:
TEST ANIMALS
- Source: Male and female HsdHan : WIST strain rats were supplied by Harlan UK Ltd, Oxon, UK.
- Age at study initiation: Approximately eight to twelve weeks old.
- Weight at study initiation: Within the weight range of 200g to 350g.
- Housing: The animals were housed in groups of five 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, free access to food (Harlan 2014 Rodent Diet, Harlan UK Ltd, Oxon, UK) was allowed throughout the study.
- Water (e.g. ad libitum): With the exception of the exposure period, free access to mains drinking water was allowed throughout the study.
- Acclimation period: At least five days.

ENVIRONMENTAL CONDITIONS
- Temperature (°C): The environmental controls were set to achieve values of 19 - 25°C
- Humidity (%): The environmental controls were set to achieve values of 30 - 70% relative humidity.
- Air changes (per hr): At least fifteen changes per hour.
- Photoperiod (hrs dark / hrs light): Lighting was controlled to give twelve hours continuous light and twelve hours darkness.

Administration / exposure

Route of administration:
inhalation: dust
Type of inhalation exposure:
nose only
Vehicle:
other: no vehicle
Details on inhalation exposure:
GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus:
A dust atmosphere was produced from the test material 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. The cylindrical exposure chamber had a volume of approximately 30 litres (dimensions: 28 cm diameter x 50 cm high). The concentration within the chamber was controlled by adjusting the test material 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.

- Exposure chamber volume:
Approximately 30 litres (dimensions: 28 cm diameter x 50 cm high).

- 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.

- Source and rate of air:
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.

- Method of conditioning air:
Compressed air passed through a water trap and respiratory quality filters.

- System of generating particulates/aerosols:
A dust atmosphere was produced from the test material 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.

- 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).

- Treatment of exhaust air:
Filtered.

- 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.

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 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 material. 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 material used by the total volume of air passed through the chamber.


- Samples taken from breathing zone: yes

VEHICLE
Not applicable.

TEST ATMOSPHERE (if not tabulated)
- Particle size distribution: Inhalable fraction (% < 4 µm): 53.8%
- MMAD (Mass median aerodynamic diameter): 3.64 µm

Analytical verification of test atmosphere concentrations:
yes
Duration of exposure:
4 h
Concentrations:
Mean achieved atmosphere concentration (mg/L): 4.98
Mean Mass Median Aerodynamic Diameter (MMAD) = 3.64 µm
Geometric Standard Deviation (GSD) = 2.74
Predicted amount less than 4 µm = 53.8%
No. of animals per sex per dose:
5 per sex per dose
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. Any evidence of overt toxicity was recorded at each observation.
Individual bodyweights were recorded prior to treatment on the day of exposure and on Days 7 and 14.

- Necropsy of survivors performed: 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:
Data evaluations included the relationship, if any, between the animals’ exposure to the test material 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 material was made.

Results and discussion

Preliminary study:
Not applicable
Effect levels
Sex:
male/female
Dose descriptor:
LC50
Effect level:
> 4.45 mg/L air
Based on:
other: MnSO4 (as anhydrous)
Exp. duration:
4 h
Mortality:
No deaths occurred in a group of ten rats exposed to a mean achieved atmosphere concentration of 4.98 mg MnSO4.H2O/L for four hours.
Clinical signs:
other: 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 and for a short period after exposure. These observations a
Body weight:
Variations in bodyweight gain are frequently seen for female animals of this strain and age during this type of study and, in isolation, are considered not to be significant.

All males and four female animals exhibited a slight bodyweight loss or reduced bodyweight gain during Week 1. With the exception of one female animal which exhibited a loss during Week 2 (this animal exhibited normal development during Week 1) animals recovered to exhibit normal development.
Gross pathology:
With the exception of one instance of dark patches on the lungs, no macroscopic abnormalities were detected at necropsy.

Any other information on results incl. tables

Mortality Data

Mean Achieved Atmosphere Concentration (mg/L)

Sex

Deaths During Exposure

Deaths Post Exposure

(1 Hour)

Deaths During Day of Observation

Total Deaths

1

2

3

4

5

6

7

8-14

4.98

Male

0

0

0

0

0

0

0

0

0

0

0/10

Female

0

0

0

0

0

0

0

0

0

0

KEY TO CLINICAL OBSERVATIONS

H

=

hunched posture

P

=

pilo-erection

Ri

=

increased respiratory rate

Wf

=

wet fur

0

=

no abnormalities detected

Individual Clinical Observations (Day of Exposure)

Mean Achieved Atmosphere Concentration (mg/L)

Animal

Number and Sex

Hours During Exposure

On Removal

From

Chamber

One Hour

Post-Exposure

1

2

3

4.98

1 Male

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

2 Male

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

3 Male

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

4 Male

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

5 Male

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

6 Female

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

7 Female

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

8 Female

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

9 Female

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

10 Female

Wf

Wf

Wf

Wf H P Ri

Wf H P Ri

Individual Clinical Observations (Recovery Period)

Mean Achieved Atmosphere Concentration (mg/L)

Animal Number and Sex

Days Post Exposure

1

2

3

4

5

6

7

8-14

4.98

1 Male

H Ri

H

0

0

0

0

0

0

2 Male

H Ri

H

0

0

0

0

0

0

3 Male

H P Ri

H

0

0

0

0

0

0

4 Male

H Ri

H

0

0

0

0

0

0

5 Male

H Ri

H

0

0

0

0

0

0

6 Female

H P Ri

H

0

0

0

0

0

0

7 Female

H Ri

H

0

0

0

0

0

0

8 Female

H P Ri

H

0

0

0

0

0

0

9 Female

H P Ri

H

0

0

0

0

0

0

10 Female

H Ri

H

0

0

0

0

0

0

Individual Bodyweights

Mean Achieved Atmosphere Concentration (mg/L)

Animal Number and Sex

Bodyweight (g) on Day:

Increment (g) During Week:

0

7

14

1

2

4.98

1 Male

286

290

301

4

11

2 Male

311

310

321

-1

11

3 Male

330

325

355

-5

30

4 Male

326

333

350

7

17

5 Male

323

322

350

-1

28

6 Female

239

221

240

-18

19

7 Female

259

248

255

-11

7

8 Female

237

233

243

-4

10

9 Female

222

233

226

11

-7

10 Female

235

233

239

-2

6

Individual Necropsy Findings

Mean Achieved Atmosphere Concentration (mg/L)

Macroscopic Observations

Animal Number and Sex

1

Male

2

Male

3

Male

4

Male

5

Male

6

Female

7

Female

8

Female

9

Female

10

Female

4.98

Lungs:

Dark Patches

 

 

P

 

 

 

 

 

 

 

 

 

N

N

 

N

N

N

N

N

N

N

Applicant's summary and conclusion

Interpretation of results:
GHS criteria not met
Conclusions:
No deaths occurred in a group of ten rats exposed to a mean achieved atmosphere concentration of 4.98 mg/L for four hours. It was therefore considered that the acute inhalation median lethal concentration (4 hr LC50) of MnSO4.H2O, in the HsdHan : WIST strain rat, was greater than 4.98 mg/L. The equivalent LC50 value for the anhydrous form of this material is considered to be >4.45 mg/L.
On the basis of this result, MnSO4 does not meet the criteria for classification in the EU in accordance with both Council Directive 67/548/EEC as amended and Regulation (EC) No 1272/2008 and will not require labelling for inhalation toxicity.
Executive summary:

Introduction. A study was performed to assess the acute inhalation toxicity of the test material. The method used followed that described in the OECD Guidelines for Testing of Chemicals (1981) No. 403 “Acute Inhalation Toxicity” referenced as Method B2 (Inhalation) of Commission Regulation (EC) No. 440/2008.

Methods. A group of ten HsdHan: WIST strain rats (five males and five females) was exposed to a dust atmosphere. The animals were exposed for four hours using a nose only exposure system, followed by a fourteen day observation period.

Results. The mean achieved atmosphere concentration was as follows:

Atmosphere Concentration

Mean Achieved (mg/L)

Standard Deviation

Nominal (mg/L)

4.98

0.88

57.2

The characteristics of the achieved atmosphere were as follows:

Mean Achieved Atmosphere Concentration (mg/L)

Mean Mass Median Aerodynamic Diameter (µm)

Inhalable Fraction

(% <4 µm)

Geometric Standard Deviation

4.98

3.64

53.8

2.74

The mortality data were summarised as follows:

Mean Achieved Atmosphere Concentration (mg/L)

Deaths

Male

Female

Total

4.98

0/5

0/5

0/10

Clinical Observations. Common abnormalities noted during the study included increased respiratory rate, hunched posture, pilo-erection and wet fur. Animals recovered quickly to appear normal from Day 3 post-exposure.

Bodyweight. All males and four female animals exhibited a slight bodyweight loss or reduced bodyweight gain during Week 1. With the exception of one female animal which exhibited a loss during Week 2 (this animal exhibited normal development during Week 1) animals recovered to exhibit normal development.

Necropsy. With the exception of one instance of dark patches on the lungs, no macroscopic abnormalities were detected at necropsy.

Conclusion. No deaths occurred in a group of ten rats exposed to a mean achieved atmosphere concentration of4.98mg/L for four hours. It was therefore considered that the acute inhalation median lethal concentration (4 hr LC50) of MnSO4, in the HsdHan: WIST strain rat, was greater than 4.98mg/L. The equivalent LC50 value for the anhydrous form of this material is considered to be >4.45mg/L.

On the basis of this result, MnSO4does not meet the criteria for classification in the EU in accordance with both Council Directive 67/548/EEC as amended and Regulation (EC) No 1272/2008 and will not require labelling for inhalation toxicity.