Appendix D Food Codes for NHANES - OEHHA

Scientific Review Panel Draft February, 2012
Bress and Bidanset (1991) studied percutaneous absorption of lead in vitro using
human abdominal skin obtained from autopsy, and guinea pig dorsal skin. PbO
or lead acetate (10 mg) in saline solution was applied to 1.3 cm 2 skin samples.
After 24 hours, the lead content of the saline reservoir fluid was measured. The
lead content of the skin samples after exposure was not measured. In this
experiment, 0.05% of the applied dose of lead acetate was recovered in the
reservoir fluid, and less than 0.01% of the PbO. There was no difference
between human and guinea pig skin.
Bress and Bidanset (1991) also examined in vivo percutaneous lead absorption
in guinea pigs. Lead acetate or PbO, mixed in aqueous solution, was applied to
a shaved area (2 cm 2 ) of the back (300 mg lead per kg body weight). After
exposure for 1 week, the animals were killed and lead was measured in blood,
brain, liver and kidney. Percent of applied dose absorbed could not be
determined from this study. However, the concentration of lead in the measured
tissues following lead oxide exposure was similar to that from control animals. In
contrast, the lead concentration in measured tissues following lead acetate
exposure was greater than controls, although absorption was considered poor,
and statistics were not provided.
Moore et al. (1980) studied percutaneous absorption of lead acetate in humans
from two commercial hair dye products. The products (one a lotion and one a
cream) were spiked with lead-203 ( 203 Pb) and applied to each subject’s forehead
(n=8) for 12 hours. The preparations were applied in various forms (wet and
dried) with periods of one month between each application. Lead absorption was
estimated from blood counts, whole-body counts, and urine activity. Results
were normalized for each subject by administration of an intravenous tracer dose
of lead chloride.
The mean uptake of 203 Pb activity, measured in whole body at 12 hours, was
greatest when the preparation was dried and skin was slightly abraded (0.18% of
applied dose). The mean absorption including all methods of application
(measured in whole body at 12 hours) was 0.058% with a range of 0-0.3%. It
has been noted that the presence of colloidal sulphur in the lead acetate
formulations used by Moore et al. (1980) may have led to the formation of
insoluble lead sulfide, which would be unlikely to be significantly absorbed
through skin (Stauber et al., 1994).
In a series of studies in human volunteers, aqueous solutions of inorganic lead
salts including lead chloride and lead nitrate were shown to be rapidly absorbed
through skin within 3-6 hrs and enter the extracellular compartment, resulting in
increased concentrations of lead in the sweat and saliva but not the blood (Lilly et
al., 1988; Stauber et al., 1994). However, application of radiolabeled lead ( 204 Pb)
to skin of volunteers resulted in measurable increases of 204 Pb in the blood but
with a very short residence time (Stauber et al., 1994). Preliminary experiments
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