Acute Toxicity: inhalation.001 to 002

Acute Toxicity: inhalation.001

Administrative data

Purpose flag:

key study

Study result type:

experimental result

Study period:

From 1995-09-25 to 1995-12-01

Reliability:

1 (reliable without restriction)

Rationale for reliability incl. deficiencies:

GLP guideline study

Data source

Reference

Reference Type:

study report

Title:

Unnamed

Year:

1996

Report Date:

1996

Materials and methods

Test guideline

Qualifier:

according to

Guideline:

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

Deviations:

no

Principles of method if other than guideline:

Not applicable

GLP compliance:

yes

Test type:

standard acute method

Limit test:

no

Test materials

Identity of test material same as for substance defined in section 1 (if not read-across):

yes

Test material identityopen allclose all

Test material identity 1

Identifier:

CAS number

Identity:

10049-04-4

Test material identity 2

Identifier:

EC number

Identity:

233-162-8

Details on test material:

- Name of test material (as cited in study report): Chlorine dioxide, ClO2
- Lot/Batch number: None – in situ generation: method and equipment provided by ELF ATOCHEM
- Description: Gas
- Purity: Residual chlorine: maximum 3 ppm
- Stability: Extemporaneous generation was used
- Impurities: residual chlorine, maximum 3 ppm
- Molecular Mass: 67.5 g

Test animals

Species:

rat

Strain:

Wistar

Sex:

male/female

Details on test animals and environmental conditions:

TEST ANIMALS
- Source: Charles River France
- Age at study initiation: 6-8 weeks
- Weight at study initiation: 175-250 g (males), 150-200 g (females)
- Fasting period before study: no data
- Housing: in individual cages
- Diet (e.g. ad libitum): ad libitum
- Water (e.g. ad libitum): filtered water ad libitum
- Acclimation period: the minimum acclimatization period lasted for 5 days

ENVIRONMENTAL CONDITIONS
- Temperature (°C): 22° ± 2°C
- Humidity (%): 30% minimum
- Air changes (per hr):
- Photoperiod (hrs dark / hrs light): 12 hours dark/ 12 hours light

IN-LIFE DATES: no data

Administration / exposure

Route of administration:

inhalation: gas

Type of inhalation exposure:

other: oro-nasal

Vehicle:

other: no data

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
- Exposure apparatus: oro-nasal exposure chamber is composed of a vertical stainless steel cylinder. It included 4 movables stages. The 2 middle stages contained glass cylinders, nested radially. The upper part of the chamber included tubes for the inlet of the test atmosphere.
- Exposure chamber volume: 2 L
- Method of holding animals in test chamber: cylinder
- System of generating vapor: procuded by a device according to the method described in the ref 95/TEPO/0257/MV-724700 ELF ATOCHEM. According to the wanted concentration of chlorine dioxide, a peristaltic pump introduced a fitted volume of a 100 g/L sodium chlorite solution in a balloon flask containing sulphuric acid (5 N). This balloon had three exhaust and inlet manifolds. At the same time, an airflow was introduced by bubbling in this balloon. This constant air flow (300 L/hour) was manages by a rotameter and was measured by a gas meter. This airflow containing chlorine dioxide was propelled in a second balloon to be washed by bubbling in a sodium chlorite solution (100 g/L). This solution was renewed continuously, in order to maintain acidic pH. This washing allowed to eliminate traces of residual chlorine. At the washing balloon exhaust, gas flow was diluted before to be carried along into the rats exposure cylinder. The final air flow was 1060 L/hour, which corresponds to 530 changes per hour.
- Treatment of exhaust air: at chamber emergence, waste was processed before being rejected into the atmosphere.
- Temperature, humidity, pressure in air chamber:

TEST ATMOSPHERE
- Brief description of analytical method used: iodometry

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

4 h

Concentrations:

Nominal concentration: 0, 45, 70, 106 and 129 mg/m³
Analytical concentration: 0, 46, 71, 107 and 128 mg/m³

No. of animals per sex per dose:

5 rats/sex/group

Control animals:

yes

Details on study design:

- Duration of observation period following administration: 14 days
- Frequency of observations and weighing: upon arrival and then daily throughout the 14 days of the study
- Necropsy of survivors performed: yes (complete)
- Other examinations performed: Clinical observations, necropsy and histopathology. Mortality was noted daily.

Statistics:

Method of determination of LD50: Litchfield and Wilcoxon

Results and discussion

Preliminary study (if fixed dose study):

Not applicable

Effect levels

Sex:

male/female

Endpoint:

LC50

Effect level:

89 mg/m³ air

Based on:

test mat.

95% CL:

69 - 119

Exp. duration:

4 h

Remarks:

The LC50 was a calculated value.

Mortality:

See table 7.2.2/1 for mortality data.

Clinical signs:

Clinical signs observed in all dose groups include: respiratory distress (abdominal respiration, noisy respiration, laboured respiration and nasal secretion) and general weakness (piloerection, hunched back, decrease of activity and weight loss / thin body condition).

Body weight:

Early mortality in all but the lowest dose and control groups prevented the evaluation of statistically significant weight changes. Whatever the tested concentration, a delay in the body weight gain with weight loss is observed for 3 days at least after the exposure to chlorine dioxide.
For the lowest dose group rats (no mortality) this period of weight loss is followed by a period of weight gain which appears similar to the control group, and indicates the reversibility of lesions.

Gross pathology:

Lungs from dosed animals showed frequent mottling, redness and depressed areas. Shrunken spleens were also noted in some animals which received ClO2.
The main lesion induced by ClO2 is the destruction of alveolar walls, which creates pulmonary emphysema lesions. This emphysema was found on all rats of the study (except control) whatever the tested concentration. The severity of the lesion is proportional to the dose. The lowest grading is observed with rats exposed to the lowest concentration. The differences of mortality between rats (incidence/precocity) restrict this observation.
Rats found dead early had lesions of edema too.

Other findings:

No data

Any other information on results incl. tables:

Table 7.2.2/1: Table for Acute Toxicity
Dose [mg/m3]	Number of dead / number investigated		Time of death	Observations
	Male	Female
0	0/5	0/5	-
45	0/5	0/5	-
70	3/5	0/5	Day 1 (1), day 9 (2)
106	4/5	2/5	Day 1 (4), day 8 (1), day 13 (1)
129	5/5	4/5	Day 1 (5), day 8 (3), day 9 (1)
LD50 value	89 mg/m3 (32 ppm) with 95% confidence limits: 69 mg/m3 (24.6 ppm) - 119 mg/m3 (41.6 ppm)

Applicant's summary and conclusion

Conclusions:

The LC50 (4 hours) is calculated to be 89.6 mg/m3 (32 ppm) (with 95% confidence limits: 69 mg/m3 (24.6 ppm) - 119 mg/m3 (41.6 ppm)). 
Under the test conditions, Chlorine dioxide gas is classified:
- as very toxic according to the Directive 67/548/EC
- in category 1 according to the CLP regulation (1272/2008)

Executive summary:

In an acute inhalation toxicity study (EU Method B.2 (Acute Toxicity (Inhalation)) conducted in compliance with GLP, groups of young adult Wistar rats were exposed by oro-nasal inhalation to Chlorine Dioxide for 4 hours at concentrations of 0, 45, 70, 106 and 129 mg/m3. Then, animals were observed for 2 weeks post exposure for clinical signs, body weight changes and finally gross autopsy was performed at the end of the experiment.

Clinical signs observed in all dose groups included: respiratory distress and general weakness. Early mortality in all but the lowest dose and control groups prevented the evaluation of statistically significant weight changes. Whatever the tested concentration, a delay in the body weight gain with weight loss is observed for 3 days at least after the exposure to chlorine dioxide. For the lowest dose group rats (no mortality), this period of weight loss is followed by a period of weight gain which appeared similar to the control group, and indicated the reversibility of lesions. Lungs from treated animals showed frequent mottling, redness and depressed area. The main lesion induced by ClO2 is the destruction of alveolar walls, which creates pulmonary emphysema lesions. This emphysema was found on all rats of the study (except control) whatever the tested concentration. The severity of the lesion is proportional to the dose. Animals died by respiratory deficiency.

LC50combined = 89 mg/m3air (95% CL 69 -119 mg/m3).

This acute inhalation study is classified as acceptable. It does satisfy with the guidelines requirements for an inhalation study (EU Method B.2) in the rats. Under the test conditions, Chlorine dioxide gas is classified as very toxic according to the Directive 67/548/EC and in category 1 according to the CLP regulation (1272/2008).

Interpretation of results:

very toxic

Criteria used for interpretation of results:

EU

Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number does however not guarantee that the information in the dossier is correct or that the dossier is compliant with Regulation (EC) No 1907/2006 (the REACH Regulation). This information has not been reviewed or verified by the Agency or any other authority. The content is subject to change without prior notice.
Reproduction or further distribution of this information may be subject to copyright protection. Use of the information without obtaining the permission from the owner(s) of the respective information might violate the rights of the owner.

Acute Toxicity: inhalation.002

Administrative data

Study result type:

experimental result

Study period:

no data

Reliability:

3 (not reliable)

Rationale for reliability incl. deficiencies:

Does not meet important criteria of today standard methods

Data source

Reference

Reference Type:

publication

Title:

Chlorine dioxide - Toxicity in animal experiments and industrial risks.

Author:

Dalhamn T.

Year:

1957

Bibliographic source:

A.M.A. Archives of Industrial Health, 15: 101-107

Materials and methods

Test guideline

Qualifier:

no guideline followed

Principles of method if other than guideline:

Rats were exposed to Chlorine Dioxide by gas inhalation at dose level of 260 ppm for two hours.

GLP compliance:

no data

Test type:

standard acute method

Limit test:

no

Test materials

Identity of test material same as for substance defined in section 1 (if not read-across):

yes

Test material identityopen allclose all

Test material identity 1

Test material identity 2

Details on test material:

Chlorine dioxide gas (purity and batch number not stated)

Test animals

Species:

rat

Strain:

no data

Sex:

no data

Details on test animals and environmental conditions:

No data

Administration / exposure

Route of administration:

inhalation: gas

Type of inhalation exposure:

no data

Vehicle:

air

Details on inhalation exposure:

Compressed air and ClO2 gas (the latter via air bubbled through a solution of ClO2 were mixed in a mixing chamber. After passing through the exposure chamber, ClO2 gas was allowed to escape either through a fume cupboard or through a Peligot tube containing KI solution and via a drying tower through a gas meter. To maintain a constant concentration, the gas was changed every 30 minutes.

Analytical verification of test atmosphere concentrations:

yes

Duration of exposure:

2 h

Concentrations:

Nominal concentration = 260 ppm (728 mg/m3)
Actual concentrations measured = 265, 264, 266 and 245 ppm.

No. of animals per sex per dose:

4 rats

Control animals:

no

Details on study design:

Urine examined for protein and weight recorded (frequency unstated)
Organs examined at necropsy: kidneys, liver and lungs.

Statistics:

No data

Results and discussion

Preliminary study (if fixed dose study):

Not applicable

Mortality:

One of the rats died during exposure and the remaining three rats were sacrificed immediately following the 2-hour exposure period

Clinical signs:

Ocular discharge and epistaxis were especially prominent.

Body weight:

No data

Gross pathology:

Microscopic examination revealed pulmonary edema and circulatory engorgement

Other findings:

No data

Any other information on results incl. tables:

No data

Applicant's summary and conclusion

Executive summary:

A single 2-hour inhalation exposure of four rats to a chlorine dioxide concentration of 260 ppm (728 mg/m3) was conducted.

Urine was examined for protein and weight recorded. At the end of the experiment, animals were sacrified and kidneys, liver and lungs were examined at necropsy.

The rats were severely affected. Ocular discharge and epistaxis were especially prominent. One rat died after about an hour's exposure. The others were killed as soon as exposure had ceased. The kidneys, liver, spleen and lungs of all four rats were microscopically examined.Pulmonary edema and circulatory engorgement were invariably present.

Information on Registered Substances comes from registration dossiers which have been assigned a registration number. The assignment of a registration number do