Appendix D Food Codes for NHANES - OEHHA

Scientific Review Panel Draft February, 2012
was also found at the dermal-epidermal junction and the upper mid-dermis.
Chromium levels differed considerably between different biopsies, but the
content of chromium was the same order of magnitude at all exposure durations
indicating that a steady state was reached within 5 hrs of exposure.
Alternatively, Mali et al. (1964) measured the disappearance of a radiolabeled
chromate solution absorbed dermally in two human volunteers and determined
penetration into stratum corneum by tape stripping. Application of a 0.02 ml
0.25% dichromate solution (containing 50 µg Cr(VI)) on a patch to the arm for 12
hrs resulted in the disappearance, and presumed absorption, of 22 µg Cr into the
skin. Tape stripping of stratum corneum removed 0.35 µg of radiolabel in the
skin.
Systemic uptake of chromium was studied in four human volunteers following a
three hour submersion in a tub of water containing 22 mg/L Cr(VI) as potassium
dichromate (Corbett et al., 1997). Urinary chromium excretion showed large
intra-individual variability. Five-day total Cr urinary excretion above historical
background ranged from 17.5 to 1.4 µg, with an average of 6.1 µg. Urine levels
of chromium were normal in three volunteers by day 2, although a fourth
volunteer excreted elevated levels of chromium up to the end of the experiment
on day 5. Elevated blood and serum levels of chromium were recorded within 1
hr after end of exposure. Chromium content of red blood cells was generally
increased about 2-fold, and serum content was increased about 3- to 5-fold.
Chromium levels in red blood cells and serum had returned to control levels 2
days after exposure. The systemic uptake rate through skin ranged from 4.1E-04
to 7.5E-05 µg/cm 2 -hr with an average of 1.5E-04 µg/cm 2 -hr.
Aqueous solutions of Cr(VI) as potassium dichromate, and Cr(III) as chromium
trichloride and chromium nitrate were applied in vitro to full thickness human
abdominal skin in diffusion cells at a chromium content of 0.034 M
(Gammelgaard et al., 1992). Test solutions of 556 µl/cm 2 were applied over a
skin surface area of 1.8 or 0.7 cm 2 . After 190 hrs exposure of skin to the
dichromate, 134 and 12 µg Cr/cm 2 were found in the epidermis and dermis,
respectively. Only 0.037 µg Cr/cm 2 was found in the recipient phase. A total
Cr(VI) permeation of 15% was calculated. Significantly less Cr(III) from either the
trichloride or nitrate was found in skin. Cr(III) content in skin was no more than
9% of the chromium content applied as Cr(VI), with no chromium found in the
recipient phase. The lower permeation of Cr(III) was considered a result of the
skin acting as a barrier to absorption of the positive Cr(III) ions.
In other experiments by Gammelgaard et al. (1992), application of the
dichromate at concentrations of 0.125, 0.25, and 0.5% to skin for 48 hrs showed
increased Cr content in skin with increasing concentration, although no Cr was
detected in the recipient phase. Total percent Cr permeation of 0.7, 0.7 and
1.1% was calculated for exposure to the 0.5, 0.25 and 0.125% dichromate
solutions, respectively. Increasing dichromate concentration (0.5 to 2.5% Cr
F-26