Slags, elec. furnace smelting, iron silicate

Health surveillance data

Administrative data

Endpoint:

health surveillance data

Type of information:

migrated information: read-across from supporting substance (structural analogue or surrogate)

Adequacy of study:

weight of evidence

Reliability:

2 (reliable with restrictions)

Rationale for reliability incl. deficiencies:

other: Acceptable, well documented study report which meets basic scientific principles. Read-across to kaolin exposure.

Data source

Reference

Reference Type:

publication

Title:

Inhalation of china stone and china clay dusts: realtionship between the mineralogy of dust retained in the lungs and pathological changes.

Author:

Wagner J.c, Pooley F.D, Gibbs A, Lyons J, Sheers G, and C-B. Moncrieff

Year:

1986

Bibliographic source:

Thorax 41, 190-196

Materials and methods

Study type:

human medical data

Endpoint addressed:

repeated dose toxicity: inhalation

Test guideline

Qualifier:

no guideline required

Principles of method if other than guideline:

The lungs of 62 men, whose previous occupational exposure to china clay dust might have contributed to their death, were examined macroscopically and histologically. Available chest radiographs were studied, and samples of lung tissue were submitted for mineralogical analysis.

GLP compliance:

not specified

Test material

Test material information

Constituent 1

Reference substance name:

China clay

IUPAC Name:

China clay

Constituent 2

Reference substance name:

China clay and stone

IUPAC Name:

China clay and stone

Details on test material:

The cases were divided into three groups of exposure:
a) China clay (kaolinite > 90% by mass, quarz <1.1% by mass and feldspars <1.0% by mass
b) kaolinite < 90% by mass, quarz >0.9% by mass and feldspars >1.0% by mass
c) miscellaneous (fairly diverse mineral compositions)

Method

Type of population:

occupational

Ethical approval:

not specified

Details on study design:

The lungs of 62 men with suspected pneumoconiosis, whose previous occupational exposure to china clay dust might have contributed to their death, were examined macroscopically and histologically. Available chest radiographs were studied, and samples of lung tissue were submitted for mineralogical analysis. All men had been employed in the production of China clay or china stone.

Results and discussion

Results:

The radiological data showed that those lungs with interstitial changes and a high kaolinite content tended to show irregular radiological changes, while nodular opacities were more common in those with a high quartz content.
The pathological examination showed that nodular fibrosis was statistically significantly related to the quartz concentration. Interstitial fibrosis, on the other hand seemed to be related to the kaolinite concentration. However, there was no statistically significant relationship between kaolinite concentration and interstitial fibrosis grades.

Any other information on results incl. tables

The study supports previous epidemiological and radiological studies, indicating that the risk for developing kaolinite pneumoconiosis increases with the dryness of the material handled and cumulative years of exposure.

It should be noticed that the study group was small, and pneumoconiosis had been identified only in a few of the subjects during their lifetime. The patients were mainly elderly, and therefore the findings reflect much higher exposure levels than in the industry of today.

Applicant's summary and conclusion

Executive summary:

The lungs of 62 men with suspected pneumoconiosis, whose previous occupational exposure to china clay dust might have contributed to their death, were examined macroscopically and histologically. Available chest radiographs were studied, and samples of lung tissue were submitted for mineralogical analysis. All men had been employed in the production of China clay or china stone. The findings of nodular fibrosis were statistically significantly related to the quartz concentrations measured in the lung samples. Interstitial fibrosis, on the other hand seemed to be realted to the kaolinite concentration. However, there was no statistically significant relationship between kaolinite concentration and interstitial fibrosis grades.