Registration Dossier

Toxicological information

Direct observations: clinical cases, poisoning incidents and other

Administrative data

Endpoint:
direct observations: clinical cases, poisoning incidents and other
Type of information:
other: case report
Adequacy of study:
disregarded due to major methodological deficiencies
Study period:
1980
Reliability:
3 (not reliable)
Rationale for reliability incl. deficiencies:
other: Significance and origin of the reported findings remain unclear.

Data source

Reference
Reference Type:
publication
Title:
Rare Earth Pneumoconiosis
Author:
Husain HM, Dick JA, Kaplan YS
Year:
1980
Bibliographic source:
J. Soc. Occup. Med., 30, 15-19

Materials and methods

Study type:
clinical case study
Endpoint addressed:
repeated dose toxicity: inhalation
Test guideline
Qualifier:
no guideline available
Principles of method if other than guideline:
Report of the results of a routine chest Radiograph of an emplyee who was involved in the handling of rare earth concentrate.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Details on test material:
- Name of test material (as cited in study report): Rare earth concentrate
- Composition:
- rare earth oxides: 60%
- Calcium oxide: 9%
- fluorine: 6%
- barium sulphate: 1.1%
- silicon dioxide: 1.0%
- other oxides (Mn, Sr etc): 0.9%
- Iron oxide: 0.6%
- magnesium oxide: 0.3%
- water: 0.1%
- traces of thoriumoxide.
The rare earth oxide fraction was reported to have the following composition:
- Cerium: 50%
- Lanthanum 31.1%
- Neodymium: 12.9%
- Praseodymium: 5.0%
-Samarium: 0.62%
- Gadolinium: 0.2%
- Europium: 0.11 %
- Yitrium: 0.05%
other: 0.02%

Method

Type of population:
occupational
Subjects:
- Number of subjects exposed: 2
- Sex: male
- Age: 34, other persons age not given
- Race: not stated
- Demographic information: one other occupation 18 months in building, 10 years in the rare earth production process
- Known diseases: none
- Other: did not follow hygiene advice
Ethical approval:
not applicable
Route of exposure:
inhalation
Reason of exposure:
intentional, occupational
Exposure assessment:
not specified
Details on exposure:
Employment for over 10 years in a dry process involving handling of rare earth concentrate. The work atmosphere is described as containing dust particles deposited onto machines and circulating in the air. Exposure not quatified.
Examinations:
Repiratory function tests:
Vital capacity
FEV1
Inspiratory reserve volume
Tidal volume
Expiratoty reserve volume
Residual volume
Total lung capacity
Chest X-ray
clincal chemical blood analysis: calcium, phosphate, alkaline phosphatase, urea, electrolytes, serum proteins.
Medical treatment:
none

Results and discussion

Clinical signs:
All lung function parameters were normal and no other clinical signs were observed.
No changes in the clincal chemistry blood parameters were observed.
Results of examinations:
All lung function parameters of both subjects were normal.
Chest radiography of one worker was normal, while one showed the following findings:
Discrete nodular shadowing in particular in the middle zones of each lung. The nodules were opaque and the authors conclude that the apparance was consitent with occupational dust exposure classified as category 22Q according to ILO 1971. Another chest radiograph taken 11 months later showed essentially the same findings without any indication of change. No firm conclusions could be drawn on the significance of the radiological findings and their origin.

Applicant's summary and conclusion

Conclusions:
One case of a chest x-ray aparently showing dust deposits in the lung without an impairment of lung fuction, clincal chemistry parameters and other clincal signs was described in a worker occupationally handling rare earth concentrates for more than 10 years. Another worker with comparable work history had a normal chest x-ray result. Exposure was to a mixture of metal and other inorganic components, but the level of exposure was not determined. No causal relationship to lanthanium oxide expsoure can be established from this study.
Executive summary:

One case of a chest x-ray aparently showing dust deposits in the lung without an impairment of lung fuction, clincal chemistry parameters and other clincal signs was described in a worker occupationally handling rare earth concentrates for more than 10 years. Another worker with comparable work history had a normal chest x-ray result. Exposure was to a mixture of metal and other inorganic components, but the level of exposure was not determined. No causal relationship to lanthanium oxide expsoure can be established from this study.