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epidemiological data
Type of information:
migrated information: read-across based on grouping of substances (category approach)
Adequacy of study:
supporting study
Study period:
1973 or earlier
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: 2e The study was well documented and meets generally accepted scientific principles, but was not conducted in compliance with GLP.

Data source

Referenceopen allclose all

Reference Type:
Human Exposure to Ferric Sulfate Aerosol: effects on pulmonary function and respiratory symptoms
Kleinman MT, Linn WS, Bailey RM, Anderson KR, Whynot JD, Medway DA, Hackney JD
Bibliographic source:
Am Ind Hyg Assoc J 42(4):298-304
Reference Type:
Reference Type:
Ferric Sulphate
Bibliographic source:
Dang Prop Ind Mat Rep 7(20):75-9

Materials and methods

Study type:
ecological study
Endpoint addressed:
respiratory irritation
repeated dose toxicity: inhalation
Test guideline
no guideline followed
Principles of method if other than guideline:
To determine whether people (normal and asthmatic) exposed for two hours to ferric sulfate aerosol would experience losses in pulmonary function or increases in the severity of respiratory symptoms.
GLP compliance:

Test material

Constituent 1
Reference substance name:
Diiron tris(sulphate)
EC Number:
EC Name:
Diiron tris(sulphate)
Cas Number:
diiron tris(sulphate)
Details on test material:
Ferric sulfate.
No further details available.


Details on study design:
Subjects served as their own control by blind exposure to 'sham' aerosol. The investigation was conducted as a 'double blind' study. Volunteers (38) were exposed to 75 µg/m3 aerosol for 2 hours on each of 5 days. The group average results were contrasted between day (sham or exposure) and conditions (pre- and post-exposure) using a two-way analysis of variance with repeated measure. A statistically significant interaction between day and condition (p< 0.05) was considered to indicate a possible exposure related change in pulmonary function. The replicate function determinations for each individual were also evaluated using a two-way analysis of variance. Because of the small number of tests available, a lower level of significance (p < 0.10) was accepted as indicating a possible exposure-related change. The concentration of ferric sulphate used in this study, 75 µg/m³, was considered by the authors to be “probably higher than ambient levels would be even in coal-burning urban areas”.
Exposure assessment:
Details on exposure:
TYPE OF EXPOSURE: exposure chamber

TYPE OF EXPOSURE MEASUREMENT: 63 m3 stainless-steel walled, environmentally controlled chamber

EXPOSURE LEVELS: 75 µg Fe2(SO4)3/m3, equivalent to an iron concentration of 20 µg/m3



DESCRIPTION / DELINEATION OF EXPOSURE GROUPS / CATEGORIES: 20 subjects with "normal" pulmonary function and no history of lung disease and 18 subjects who were diagnosed as "asthmatics" participated in the experiment. It was presupposed that the asthmatics might be more sensitive to the respiratory insult than the normals, so the normal group was exposed and their data evaluated before the asthmatics were tested.
Each subject underwent exposures on two separate days: one a sham in highly purified air, and the other in the test atmosphere.
Statistical methods:
Differences between pulmonary function results for sham and exposure days was indicated by interaction between day and condition in a two-way analysis of variance.

Results and discussion

Only five of the 38 volunteers tested showed patterns indicative of a decrement in pulmonary function. Nine of the subjects exhibited significant improvement in function. None of the subjects reported more than slight changes in symptoms during exposure. The authors considered that the tendency for a subject to improve after the ferric sulphate exposure could be related to allergy status, smoking history, or a combination of these factors. Furthermore, they recorded that “it is encouraging to note that at the relatively high aerosol concentration used in this study, there were no significant detrimental changes in the (study) population as a whole”. The study appears to have been well conducted and the conclusions are consistent with the data presented. It may be assumed that ferric sulphate aerosols do not produce any clear pulmonary effects in either normal persons or asthmatics.

Applicant's summary and conclusion

In a pre-GLP study into the respiratory effects of exposure to ferric sulfate aerosol in humans (reliability score 2) the authors concluded that "The study appears to have been well conducted  and the conclusions are consistent with the data presented. It may be assumed that ferric sulphate aerosols do not produce any clear pulmonary effects in either normal persons or asthmatics."
Executive summary:

In a pre-GLP study into the respiratory effects of exposure to ferric sulfate aerosol in humans (reliability score 2) volunteers (38) were 

exposed to 75 µg/m3 aerosol for 2 hours on each of 5 days. The investigation was conducted as a 'double blind' study. Subjects served 

as their own control by blind exposure to 'sham' aerosol. The group average results were contrasted between day (sham or exposure) 

and conditions (pre- and post-exposure) using a two-way analysis of variance with repeated measure. Only five of the 38 volunteers 

tested showed patterns indicative of a decrement in pulmonary function. Nine of the subjects

exhibited significant improvement in function. None of the subjects reported more than slight changes in symptoms during exposure. 

The authors considered that the tendency for a 

subject to improve after the ferric sulfate exposure could be related to allergy status, smoking history, or a combination of these factors. Furthermore, they recorded  that "it is encouraging to note that at the relatively high aerosol 

concentration used in this study, there were no significant decremental changes in the (study) population as a whole." The study appears 

to have been well conducted and the conclusions are consistent with the data presented. It may be assumed that ferric sulphate aerosols 

do not produce any clear pulmonary effects in either normal persons or asthmatics.