Appendix D Food Codes for NHANES - OEHHA

Scientific Review Panel Draft February, 2012
Following 16 hrs of exposure, 0.3% of freshly applied 63 NiCl2 in clay soil
penetrated the skin to receptor fluid and 12.1% was found bound to skin. No
significant difference for dermal absorption from sandy soil was observed. For
the nickel solution applied to skin, 0.4 and 57.9% of the dose applied was found
in receptor fluid and bound to skin, respectively. In aged sandy and clay soil,
0.03 and 0.05% nickel was found in the receptor fluid, respectively. Only 3.1 and
3.7% of the metal was bound to skin from sandy and clay soil, respectively.
Aging nickel in the soils appeared to be complete by 3 months, as further aging
in soil for 6 and 12 months did not result in further decreased dermal
bioavailability of the metal (Abdel-Rahman et al., 1997; Abdel-Rahman et al.,
1999).
Fullerton et al. (1986) examined the permeation of nickel salts, specifically nickel
sulfate and nickel chloride, through human full-thickness breast or leg skin in
vitro. Skin excised in surgery was exposed to aqueous solutions of 184 µg/cm 2
for each nickel salt for up to 144 hrs. In the first experiment the effect of
occlusion on the permeation rate of nickel chloride was examined. Occlusion
resulted in a significantly higher permeation rate (approximately 3.6 percent of
applied dose) compared with non-occluded exposure (approximately 0.23
percent) after 144 hours.
In the second experiment, nickel ions from a chloride solution were found to pass
through the skin about 50 times faster than nickel ions from a sulfate solution.
The amount of permeation of nickel chloride was much higher (16%) at 144
hours than nickel sulfate (0.3%). However, dermal penetration of the skin was
slow, having a lag-time of about 50 hours. The occluded-skin permeation of
nickel chloride was considerably higher in experiment 2 than experiment 1 (9-
16% vs 3.6%) and was attributed by the authors to the use of breast skin from
different donors.
In another study by the researchers, the stripping method was used in vitro on
human full thickness skin following exposure to 5% nickel chloride in a 5% methyl
cellulose gel for 96 hrs under occlusion (Fullerton et al., 1988). Nickel
penetration from the gel solution gave similar results to nickel penetration of the
pure nickel salt. Skin depth profiles found 50.9% was present on and in the
stratum corneum (skin was not washed before stripping) with most of the nickel
in the upper part of the stratum coeneum, 10.6% in the epidermis, 1.6% in the
dermis, and only 0.4% reached the receptor solution.
Although the time frame and doses were different, similar dermal absorption
results were obtained by Turkall et al. (2003) with in vitro dermal exposure of pig
skin to 64 ng of radiolabeled nickel chloride. Penetration of 63 Ni in ethanol
through pig skin was 0.4% of initial dose and a total of 58% of the nickel
remained in the skin at the end of 16 hrs.
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