Appendix D Food Codes for NHANES - OEHHA

Scientific Review Panel Draft February, 2012
Following 8-hr dermal application, an increase in urinary excretion of arsenic
above background was not detectable, indicating virtually no absorption of
arsenic from CCA-treated wood residue. The researchers determined that the
absorbed dose would need to be in the range of 0.10 to 0.16% of the applied
dose to be detectable above background.
The negligible dermal absorption of arsenic from the CCA residues is a result of
arsenic chemically bound with other metals (particularly chromium) and ultimately
to the wood structure (Nico et al., 2004). The leaching characteristics of soluble
arsenic in CCA residues were also investigated by extraction in human sweat
(Nico et al., 2006). The sweat extraction procedure indicated that up to 12% of
total arsenic is available for dermal absorption from CCA-treated wood residue.
However, only 1.4% soluble arsenic was extracted with sweat from CCA-residue
aged in soil near a CCA-treated utility pole. Gastric leaching conditions resulted
in up to 2-3 times greater solubilization of arsenic from CCA-treated wood
compared to sweat leaching, indicating soil ingestion of CCA-released arsenic
can be a health concern.
F. 3.1.2 Discussion and Recommendation for Arsenic and Arsenic Compounds
ABS
Dermal exposure of skin to arsenic resulting in passage of arsenic through skin
to the bloodstream is the primary concern under the “Hot Spots” program.
However, arsenic that becomes bound in skin may also have toxicological
consequences. Regardless of route of exposure to arsenic the skin is a critical
target organ for arsenic toxicity due to local absorption and binding of sulfhydrylgroup-containing
proteins (Hostynek et al., 1993). The affinity for sulfhydryl
groups leads to arsenic’s accumulation and tenacious retention in keratin-rich
tissues such as hair, nails, and skin. Measurement of in vitro percutaneous
absorption of As(III) and As(V) by human epidermal skin cultures for 6 hrs shows
strong affinity of arsenic for the keratinocytes, with an estimated 30% of As(V)
passing through skin being retained compared to over 90% of the As(III) being
retained (Bernstam et al., 2002).
Accumulation of arsenic in the skin is characterized by hyperpigmentation,
keratoses of the palms of the hands and soles of the feet, and diffuse macular
pigmentation or diffuse darkening of the skin on the limbs and trunk, attributed to
the reduction and deposition of the element in the metallic state (Hostynek,
2003). Chronic arsenic accumulation in skin increases the susceptibility of the
skin to ultraviolet light and is associated with an increased incidence of tumors of
exposed skin, although skin cancer is primarily a result of oral arsenical
poisoning and characterized by multifocal lesions over the entire body (Hostynek
et al., 1993; OEHHA, 1999).
The key in vivo monkey study by Wester et al. (1993a) provides an average
fractional absorption of 3.9% based on two dose levels of arsenic that had been
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