Appendix D Food Codes for NHANES - OEHHA

Scientific Review Panel Draft February, 2012
available reducing power of the matrix material and excess Cr(VI) may persist for
years in soils without reduction.
Oral bioaccessibility of Cr(VI) from aged soils was determined by Stewart et al.
(2003) using a physiologically based extraction test designed to simulate the
digestive process of the stomach. It would be expected that bioaccessibility for
dermal absorption of soil Cr(VI) would be no greater than oral absorption, and
has been used to estimate dermal exposure to Cr(VI) in soil in previous health
assessments (Sheehan et al., 1991).
In general, Cr(VI) bioaccessibility decreased with the aging of Cr(VI) in soils, with
decreased bioaccessibility being most rapid for the first 50 days and then slowing
dramatically between 50 and 200 days (Stewart et al., 2003). Chromium
bioaccessibility was significantly influenced by reduction processes catalyzed by
soil organic carbon. Soils with sufficient organic carbon had lower Cr(VI)
bioaccessibility values of about 10 to 20% due to enhanced reduction of Cr(VI) to
Cr(III). In soils where organic carbon was limited and reduction processes were
minimal, considerably higher Cr(VI) bioaccessibility values of 60-70% were
recorded.
Soil samples from two chromium waste sites that varied considerably in Cr(VI)
concentration were extracted with a synthetic sweat solution to determine the
potential for dermal bioaccessibility of Cr(VI) from contaminated soils (Wainman
et al., 1994). The soils examined were contaminated with slag containing
chromium from chromate and bichromate production facilities in New Jersey.
One set of soil samples contained 710 µg Cr(VI)/g soil and contained chromate
blooms, a thin layer of bright yellow crystals on the soil surface. Approximately
83% Cr(VI) was extracted in sweat from the soil with chromate blooms.
Adjusting the pH of the soil from pH 5 to 8 had little effect on Cr(VI) extraction. In
the other soil, the Cr(VI) concentration averaged 59 µg/g soil. Sweat extraction
of Cr(VI) increased from 15 to 32% with increasing soil pH from pH 5 to 8. No
Cr(VI) was extracted from the soil adjusted to pH 4. Extraction with distilleddeionized
water was also performed, resulting in 76 and 27% extraction from soil
with and without blooms, respectively.
Horowitz and Finley (1993) investigated the leaching of Cr(VI) in human sweat
from chromite ore processing residue. The New Jersey ore residue originated
from the same or similar processing facility as that investigated by Wainman et
al. (1994). The human sweat at a pH of 7.2-8.0 extracted < 0.01% of Cr(VI) from
the ore samples. Differences in the parent ore and extraction techniques were
suspected to have led to the widely varying extraction of Cr(VI) from samples
analyzed by Wainman et al. (1994) and Horowitz and Finley (1993).
Oral bioaccessibility studies have also been conducted on the New Jersey slag
material (Hamel et al., 1999). Using two different methods, chromium in the slag
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