Appendix D Food Codes for NHANES - OEHHA

Scientific Review Panel Draft February, 2012
Kimura and Otaki (1972) used liver and kidney accumulation of cadmium in
rabbits and hairless mice to estimate dermal absorption. A total dose of 30.5 mg
Cd (in an aqueous CdCl2 solution) was administered to rabbit skin (n=1) in 5
doses over 3 weeks. Two weeks after the final application, 0.40% of the applied
dose was found in liver and kidney combined. In rabbits (n=2), a total dose of 61
mg Cd was administered in multiple cream-like and milk-like ointment
applications, resulting in 0.45 and 0.61%of the applied dose, respectively, in liver
and kidney combined. The type of ointment vehicle used did not appear to
greatly affect the absorption or accumulation characteristics of Cd. Dermal
absorption of cadmium in hairless mice, estimated from kidney and liver
accumulation, ranged from 0.07-0.27% after a single application of ointment
(0.61 mg Cd). Cadmium absorption after multiple ointment applications on
hairless mice ranged from 0.59 - 0.87% of applied dose.
Aqueous 1.0, 0.1 and 0.01% cadmium solutions were painted onto the skin of
mice and rats and air dried each day for ten days (Lansdown and Sampson,
1996). Perceptible skin damage occurred at the two highest doses, likely
resulting in increased dermal absorption. At the lowest dose, significantly
increased skin content of cadmium was observed in both mice (138 ng Cd/g) and
rats (248 ng Cd/g). Adequate data to estimate fractional absorption were not
provided.
Although no studies estimated dermal absorption of cadmium aged in soils,
Aringhieri et al. (1985) reported that 80% of cadmium added to a soil containing
high organic matter (14.2%) and high clay content (60%) was adsorbed to soil
particles within 10 min of addition to a soil. Tang et al. (2006) observed that
bioaccessibility of cadmium (relating closely to absorption following ingestion of
soil) in strongly acidic soils spiked with cadmium reached nearly steady state
levels as high as 77% after the first week of aging. In soils highly contaminated
with heavy metals by industrial sources, the MgCl2-exchangeable fraction of
cadmium was about 37% and was considered the most mobile and biologically
available heavy metal in the samples examined (Hickey and Kittrick, 1984).
F. 3.3.2 Discussion and Recommendation for a Cadmium and Cadmium
Compounds ABS
No in vivo studies investigating fractional absorption of cadmium from soil were
located. The human in vitro study by Wester et al. (1992) provided the only
quantitative data for dermal absorption of cadmium from soil. The retention and
concentrating of cadmium in skin with slow systemic absorption demonstrate the
necessity for including the cadmium found in exposed skin for estimating an ABS
point estimate.
The lack of quantitative in vivo studies and the use of 16 hr rather than 24 hr
exposures support a point estimate based on the highest fractional absorption of
0.2%, rather than a the lower estimate of 0.1% (based on an averaging of
F-24