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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

Data source

Reference
Reference Type:
publication
Title:
Unnamed
Year:
1975

Materials and methods

Endpoint addressed:
basic toxicokinetics
Test guideline
Qualifier:
no guideline followed
Principles of method if other than guideline:
Between 1966 and 1973, up to 35 different organs and tissues from a total of 129 cadavers were analyzed for lead content. Of this total, 119 (60 male adults, 36 female adults, and 23 male and female children) had no history of occupational exposure to lead. Seven of the remaining 10 subjects, all male adults, had defined histories of occupational lead exposure. The remaining three subjects had unknown occupational histories. Causes of death were varied, and all cases had been subjected to postmortem examination for reasons associated with unusual or ill-defined causes of death.
GLP compliance:
no

Test material

Reference
Name:
Unnamed
Type:
Constituent
Test material form:
other: body measurements
Details on test material:
Measurements in blood/bone/bodily fluids/soft tissues as specified

Method

Ethical approval:
not applicable

Results and discussion

Results:
Bone lead concentrations increased with age in both sexes, particularly in males and in dense bone, varying between mean values of 2 ppm in the ribs of children to over 50 ppm in the dense petrous temporal bones of elderly male adults. Male adults had over 30% more lead in their bones than females. Mean concentrations of lead in soft tissues varied from less than 0.1 ppm in organs such as muscle and heart to over 2 ppm in the aorta. In most tissues with lead values greater than 0.2 ppm, the male concentrations exceeded female values by about 30%. With the exception of the aorta, spleen, lung, and prostate, lead concentrations did not increase with age in the soft tissues of either sex after about the second decade of life. The concentrations of lead in the soft tissues of children were comparable to female adults, but the concentrations in bone were much lower (range of 2-5 ppm in children vs. range of 6-26 ppm in adult females).

In male adults occupationally exposed to lead, the concentrations of lead in bone exceeded the concentrations in unexposed adults within the same age group by two- to three-fold. Soft tissue lead concentrations between the two groups were less divergent.

An assessment of the total body burden of lead indicated higher levels in adult male subjects (mean value of 164.8 mg) compared to adult female subjects (mean value of 103.6 mg). Over 90% of the total body burden of lead in adults was in bone, of which over 70% was in dense bone. Male adults occupationally exposed to lead had mean total body burdens of 566.4 mg lead, of which 97% was in bone.

Lead concentrations in hair and nails were higher than soft tissue lead concentrations and varied widely. Hair lead measurements were not considered to provide a reliable assessment of lead absorption.

Applicant's summary and conclusion

Conclusions:
The authors concluded that the findings do not suggest that levels of lead in the environment, with the exception of unusual circumstances of exposure, have caused an increase of lead uptake in body tissues in recent decades and that the physiological capacity for humans to excrete varying quantities of absorbed lead appears to be well adapted to protect from the adverse effects of lead.
Executive summary:

Between 1966 and 1973, up to 35 different organs and tissues from a total of 129 cadavers were analyzed for lead content. Of this total, 119 (60 male adults, 36 female adults, and 23 male and female children) had no history of occupational exposure to lead. Seven of the remaining 10 subjects, all male adults, had defined histories of occupational lead exposure. The remaining three subjects had unknown occupational histories. Causes of death were varied, and all cases had been subjected to postmortem examination for reasons associated with unusual or undefined casuses of death. Bone lead concentrations increased with age in both sexes, particularly in males and in dense bone, varying between mean values of 2 ppm in the ribs of children to over 50 ppm in the dense petrous temporal bones of elderly male adults. Male adults had over 30% more lead in their bones than females. Mean concentrations of lead in soft tissues varied from less than 0.1 ppm in organs such as muscle and heart to over 2 ppm in the aorta. In most tissues with lead values greater than 0.2 ppm, the male concentrations exceeded female values by about 30%. With the exception of the aorta, spleen, lung, and prostate, lead concentrations did not increase with age in the soft tissues of either sex after about the second decade of life. The concentrations of lead in the soft tissues of children were comparable to female adults, but the concentrations in bone were much lower (range of 2-5 ppm in children vs. range of 6-26 ppm in adult females). In male adults occupationally exposed to lead, the concentrations of lead in bone exceeded the concentrations in unexposed adults within the same age group by two- to three-fold. Soft tissue lead concentrations between the two groups were less divergent. An assessment of the total body burden of lead indicated higher levels in adult male subjects (mean value of 164.8 mg) compared to adult female subjects (mean value of 103.6 mg). Over 90% of the total body burden of lead in adults was in bone, of which over 70% was in dense bone. Male adults occupationally exposed to lead had mean total body burdens of 566.4 mb lead, of which 97% was in bone. Lead concentrations in hair and nails were higher than soft tissue lead concentrations and varied widely. Hair lead measurements were not considered to provide a reliable assessment of lead absorption. The authors concluded that the findings do not suggest that levels of lead in the environment, with the exception of unusual circumstances of exposure, have caused an increase of lead uptake in body tissues in recent decades and that the physiological capacity for humans to excrete varying quantities of absorbed lead appears to be well adapted to protect from the adverse effects of lead.