Mercury

Acute Toxicity: inhalation

Administrative data

Endpoint:

acute toxicity: inhalation

Type of information:

experimental study

Adequacy of study:

key study

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Study reliable with restrictions

Data source

Reference

Reference Type:

publication

Title:

Lung and blood superoxide dismutase activity in mercury vapor exposed rats: effect of N-acetylcysteine treatment

Author:

Livardjani, F. et al.

Year:

1991

Bibliographic source:

Toxicology, 66, 289 - 295.

Materials and methods

Principles of method if other than guideline:

Rats were exposed whole body to mercury vapours (30 mg/m^3) for either 1 or 2 h.

GLP compliance:

not specified

Limit test:

no

Test material

Test material information

Constituent 1

Reference substance name:

Mercury

EC Number:

231-106-7

EC Name:

Mercury

Cas Number:

7439-97-6

Molecular formula:

Hg

IUPAC Name:

mercury

Details on test material:

- Name of test material (as cited in study report): mercury (vapour form administered)
No further information on the test material was stated.

Test animals

Species:

rat

Strain:

Wistar

Sex:

male

Details on test animals or test system and environmental conditions:

TEST ANIMALS
- Weight at study initiation: approx. 150 g.
- Housing: in a metabolic box.
No further information on the test animals was stated.

Administration / exposure

Route of administration:

inhalation: vapour

Type of inhalation exposure:

whole body

Vehicle:

air

Details on inhalation exposure:

GENERATION OF TEST ATMOSPHERE / CHAMBER DESCRIPTION
Rats were maintained in a metabolic box which was placed in a hermetic chamber (0.33 cm^3). Mercury vapours were introduced by a pump (3 l/min) from heated mercury contained in a flask heated outside the chamber. The air was continuously recycled and the temperature maintained at 22 +/- 0.5 °C.

TEST ATMOSPHERE
In the circulating air, Hg concentration was measured in 10-ml samples, within 5 min of initial animal exposure, by atomic absorption spectrometry (spectrometer IL 152) according to Heimbuerger et al. (Heimburger, R., Liverdjani, F., and Leroy, M.J. (1986). Analyse du mercure par spectrométrie d'absorption atomique en vapeur froide. Analysis, 14, 173.).
No further information on the inhalation exposure was stated.

Analytical verification of test atmosphere concentrations:

yes

Remarks:

see "Details on inhalation exposure" above

Duration of exposure:

1 - 2

Remarks on duration:

Group 1 was exposed for 1 h and group 2 for 2 h.

Concentrations:

Two types of Hg exposure:
Group 1: 26.6 +/- 4.7 mg Hg per m^3
Group 2. 27.0 +/- 3.8 mg Hg per m^3

No. of animals per sex per dose:

32 male rats

Control animals:

not specified

Details on study design:

The animals were sacrified 1, 2, 3, 4, 5, 6, 7 and 15 days after Hg exposure.
Observations of clinical signs were conducted. The animals either died spontaneously or were sacrified after anesthesia by i.p. injection of 350 mg/kg of ketamine. Blood was taken by cardiac puncture, the lung was excised and frozen at -70 °C. Mercury measurements were made in the blood and the lung samples. Also, superoxide dismutase activity was measured in the blood and the lung samples.
No further information on the study design was stated.

Statistics:

no data

Results and discussion

Effect levels

Effect levels 1

Sex:

male

Dose descriptor:

LC50

Effect level:

> 26.6 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

1 h

Remarks on result:

other: All animals of group 1 survived until scheduled sacrifice. (Standard deviation: +/- 4.7 mg/m^3).

Effect levels 2

Sex:

male

Dose descriptor:

LC50

Effect level:

< 27 mg/m³ air (analytical)

Based on:

test mat.

Exp. duration:

2 h

Remarks on result:

other: 20 of 32 animals of Group 2 died by asphyxia before scheduled sacrifice. No animals were alive 5 days after intoxication. (Standard deviation: 3.8 mg/m^3).

Mortality:

No animals of group 1 died in advance of sacrifice.
20 of 32 animals of Group 2 died by asphyxia before the sacrifice time. No animals were living more than 5 days after intoxication.

Clinical signs:

other: During Hg exposure, the animals of Group 1 did not show breathing difficulties. The animals of Group 2 showed dyspnoea.

Body weight:

The animals of Group 2 had also an important weight loss ranging from 15 to 25 %.

Gross pathology:

No data

Applicant's summary and conclusion

Interpretation of results:

very toxic

Remarks:

Migrated information Criteria used for interpretation of results: EU

Conclusions:

Metalic mercury is classified according to the EC Regulation No. 1272/2008 and subsequent regulations as fatal if inhaled.
According to the the criteria specified by Directive 67/548/EEC and subsequent regulations, the test item is very toxic by inhalation.