Inorganic lead as nitrate or acetate was absorbed through human forearm skin. Of 4.4 mg applied in the quantitative experiment, 3.1 mg was recovered and 1.3 mg (29 percent) was not recovered. Total lead in blood and urine did not rise, while 204Pb concentration and abundance did. The discussion also says 5 mg was applied in one experiment with 1.3 mg absorbed. Both wordings are kept. Microgram units are often printed as g or similar; values are copied as ug where the figure axis says ug/L.
Key numbers
| Analyte | Matrix | Value | Unit | Statistic | N | Where |
|---|---|---|---|---|---|---|
| Pb | iontophoresis sweat, opposite arm | 6 ± 4 | ug/L | mean ± stated spread | subject C | Fig. 1 p.5 (printed 59) |
| Pb | iontophoresis sweat, right arm | 174 | ug/L | maximum | subject C | Fig. 1 p.5 (printed 59) |
| Pb | sweat | 46 | ug/L | maximum | subject A | p.5 (printed 59) |
| Pb | sweat | 71 | ug Pb/L | maximum | subject A | p.5 (printed 59) |
| Pb | sweat | 70 | ug/L | maximum | experiment 1 | Fig. 2 p.6 (printed 60) |
| Pb | sweat | 2.3 | ug/L | maximum 204Pb | experiment 1 | Fig. 2 p.6 (printed 60) |
| Pb | sweat | 3.95 | atom percent | maximum abundance | experiment 1 | Fig. 2 p.6 (printed 60) |
| Pb | sweat | 61 | ug/L | maximum | experiment 2 | p.6 (printed 60) |
| Pb | whole blood | 1.824 | atom percent | maximum | subject A | Table 1 p.6 (printed 60) |
| Pb | serum | 0.17-0.53 | ug/L | range | subject B | Table 3 text p.7 (printed 61) |
| Pb | urine | 2.2 to 3.5 | ug/g creatinine | range | subject B | Table 4 text p.7 (printed 61) |
| Pb | urine | 3.0 ± 0.5 | ug/g creatinine | mean | subject B | p.7 (printed 61) |
Methods (brief)
Lead was applied on a membrane filter to the left arm, sometimes occluded. Sweat was collected from the opposite arm by iontophoresis or in a sauna. Lead carbonate (6.6 mg, 66 atom percent 204Pb) was not absorbed until converted to nitrate. Lead metal powder and PbO dissolution and 210Pb uptake into erythrocytes were measured in vitro.
Detection and reporting: sweat lead below detection limit 0.5 ug/L before tracer application in experiment 2; TIMS 204Pb abundance precision stated as 0.1 percent
Basis: applied mass on skin; concentrations in sweat, blood, serum, and urine
Evidence fitness
This source can support: percutaneous absorption of inorganic lead nitrate and acetate in humans; 204Pb time courses in blood, serum, sweat, and urine; in vitro dissolution and erythrocyte uptake.
It cannot support: a population blood-lead survey; lead concentration in dust or consumer products; a regulatory limit.
Limitations
Few subjects. Much of the unrecovered lead may still have been in the epidermis. The 23 and 8 figures in the sweat-excretion sentence are printed with a per-litre unit. Moore et al. 1980 (0 to 0.3 percent of applied dose in blood) is a citation and was not entered. No regulatory lead limit is set.
Related evidence
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