Registration Dossier

Administrative data

Endpoint:
health surveillance data
Type of information:
experimental study
Adequacy of study:
supporting study
Study period:
No data
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Study well documented, meets generally accepted scientific principles and acceptable for assessment. Information indicative for toxicokinetic section.
Cross-referenceopen allclose all
Reason / purpose:
reference to same study
Reason / purpose:
reference to other study

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
2008

Materials and methods

Study type:
biological exposure monitoring
Endpoint addressed:
basic toxicokinetics
Principles of method if other than guideline:
Study was conducted to examine the aluminum exposure and kinetics of aluminum in a group of shipyard workers engaged in welding and grinding when making ship hulls of aluminum and to compare these data with those of workers exposed to aluminum sulfate in aluminum sulfate production. Biological behavior of the aluminum species in the workers were assessed by changes in aluminum concentrations in biological fluids (urine and serum) over a short time (2 work days) and a long time (2 years).
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
not specified
Details on test material:
- Name of test material (as cited in study report): Aluminum sulfate

Method

Type of population:
occupational
Ethical approval:
confirmed and informed consent free of coercion received
Remarks:
study protocol was approved by the Ethics Committee of the Finnish Institute of Occupational Health.
Details on study design:
This is an observational study among workers exposed to different aluminum compounds. In this study, two groups of workers exposed to different aluminum compounds [(welders or fitters) and aluminum sulfate producers]. In addition, the exposure scenario was manipulated by varying the extent of the use of protection devices; compared the accumulation of aluminum among workers with different histories of the use of protection devices. The study concentrated on short-term changes in the aluminum concentrations in body fluids, and also to follow the long-term disappearance of aluminum among welders whose exposure ceased.

Results and discussion

Results:
The mean 8-hour time-weighted average concentration of aluminum was 1.1 (range 0.008-6.1) mg/m3 for the shipyard and 0.13 (range 0.02-0.5) mg/m3 for the aluminum sulfate plant. Welding fume contained aluminum oxide particles <0.1 μm in diameter and their agglomerates, whereas bauxite and aluminum sulfate particles ranged from 1 to 10 μm in diameter. The shipyard welders' mean postshift serum and urinary concentrations of aluminum (S-Al and U-Al, respectively) were 0.22 and 3.4 µmol/l, respectively, and the aluminum sulfate workers' corresponding values were 0.13 and 0.58 µmol/l.

After study day I, the median serum aluminum concentration in the group of 12 welders and fitters decreased by about 50% (t-test for paired samples, P<0.01) overnight in 16 hours. In contrast, the concentration of aluminum in the corresponding urine samples from the same workers did not show any consistent change (P=0.64). As regards the five aluminum sulfate plant workers, there were no trends of change overnight after study day I either for the serum aluminum or urinary aluminum concentration. It is however worth noting that, compared with the corresponding value of the welders and fitters, their serum aluminum concentration was relatively higher than the urinary aluminum concentration.

After aluminum welding at the shipyard had ceased, the median S-Al concentration decreased by about 50% (P=0.007) within a year, but there was no change (P=0.75) in the corresponding U-Al concentration.

Any other information on results incl. tables

See the attached document for tables of results

Applicant's summary and conclusion

Conclusions:
About 1% of aluminum in welding fume appears to be rapidly absorbed from the lungs, whereas an undetermined fraction is retained and forms a lung burden. A higher fractional absorption of aluminum seems possible for aluminum sulfate workers without evidence of a lung burden. After rapid absorption, aluminum is slowly mobilized from the lung burden and dominates the S-Al and U-Al concentrations of aluminum welders. For kinetic reasons, S-Al or U-Al concentrations cannot be used to estimate the accumulation of aluminum in the target organs of toxicity. However, using U-Al analysis to monitor aluminum welders' lung burden seems practical.
Executive summary:

Airborne and internal aluminum exposure was assessed for 12 aluminum welders in a shipyard and 5 manufacturers of aluminum sulfate. Particles were characterized with X-ray diffraction and scanning electron microscopy. Aluminum in air and biological samples was analyzed using electrothermal atomic absorption spectrometry. Basic toxicokinetic features were inferred from the data.

 

The mean 8-hour time-weighted average concentration of aluminum was 1.1 (range 0.008-6.1) mg/m3 for the shipyard and 0.13 (range 0.02-0.5) mg/m3 for the aluminum sulfate plant. Welding fume contained aluminum oxide particles <0.1 µm in diameter and their agglomerates, whereas bauxite and aluminum sulfate particles ranged from 1 to 10 µm in diameter. The shipyard welders' mean postshift serum and urinary concentrations of aluminum (S-Al and U-Al, respectively) were 0.22 and 3.4 µmol/l, respectively, and the aluminum sulfate workers' corresponding values were 0.13 and 0.58 µmol/l. Between two shifts, the welders' S-Al concentration decreased by about 50% (P<0.01), but their U-Al concentration did not change (P=0.64). No corresponding temporal changes occurred among the aluminum sulfate workers. After aluminum welding at the shipyard had ceased, the median S-Al concentration decreased by about 50% (P=0.007) within a year, but there was no change (P=0.75) in the corresponding U-Al concentration.

 

About 1% of aluminum in welding fume appears to be rapidly absorbed from the lungs, whereas an undetermined fraction is retained and forms a lung burden. A higher fractional absorption of aluminum seems possible for aluminum sulfate workers without evidence of a lung burden. After rapid absorption, aluminum is slowly mobilized from the lung burden and dominates the S-Al and U-Al concentrations of aluminum welders. For kinetic reasons, S-Al or U-Al concentrations cannot be used to estimate the accumulation of aluminum in the target organs of toxicity. However, using U-Al analysis to monitor aluminum welders' lung burden seems practical.