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Toxicological information

Exposure related observations in humans: other data

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Administrative data

Endpoint:
exposure-related observations in humans: other data
Type of information:
experimental study
Adequacy of study:
supporting study
Reliability:
2 (reliable with restrictions)
Rationale for reliability incl. deficiencies:
other: Acceptable publication which meets basic scientific principles

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1990

Materials and methods

Endpoint addressed:
basic toxicokinetics
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Study to investigate fluoride and aluminium kinetics in cryolite workers.
GLP compliance:
not specified

Test material

Reference
Name:
Unnamed
Type:
Constituent

Method

Ethical approval:
confirmed, but no further information available
Details on study design:
Eight male workers at a cryolite concentrator participated in a 4-day study after 5 days of vacation. Dust exposures were 0.16 to 21.2 mg/m3. Plasma concentrations and urinary excretion of fluoride and aluminium were determined during a 4-day working week. Urine was collected before work began and during two 4 hr periods.
Exposure assessment:
measured
Details on exposure:
Cryolite exposure was monitored by personal filters and varied between 0.16 and 21.2 mg/m3.

Results and discussion

Results:
Preshift urine fluoride concentrations increased during the week. Fluoride concentrations in postshift urine and serum both correlated with the dust exposures. Serum fluoride concentrations decreased with a half-life of 3.3 to 6.9 hr after work. Fluoride clearance was 40.5 to 76.5 ml/min at urinary flow rates of 0.89 to 2.21 ml/min. Median preshift aluminium concentrations were 1.2 μmol/L in serum and 2.4 μmol/L in urine and were relatively high compared to levels during the working week (range of medians for serum: 0.8-0.9 μmol/L and range of medians for urine: 3.8 - 4.7 μmol/L). Workers with the highest dust exposure on a certain day had the highest serum aluminium concentrations at the end of the shift and the highest aluminium excretion after the shift. Aluminium and fluoride concentrations in the urine were significantly related. On a molar basis, almost 100 fold more fluoride (compared to aluminium) was excreted during a 24 hour period.
Based on the amounts of urinary excreted fluoride, exposure time, dust concentration and average minute volume it could be calculated, that approximately 31% of the inhaled amounts of fluoride were excreted in the urine.
Absorption of cryolite dust is dependent on the particle size, but Grandjean et al. (1990) gives no information about particle size. Therefore, it should be taken into consideration that not the total amount of cryolite dust might have been consisting of respirable particles so that even higher absorption values might be possible. Due to the uncertainties concerning particle size, respirable fraction and deposition in bones and teeth, a default value of 100% for inhalation absorption cannot be excluded.

Applicant's summary and conclusion