Appendix D Food Codes for NHANES - OEHHA

Scientific Review Panel Draft February, 2012
to TCDD, is not a significant factor for dermal absorption (Mayes et al., 2002).
On the other hand, oral studies of soil-laden TCDD do indicate aging to be factor
in the reduction of TCDD intestinal absorption (Poiger and Schlatter, 1980).
F. 4.3 Polycyclic Aromatic Hydrocarbons as Benzo[a]pyrene (BaP)
Recommended point estimate for dermal uptake from soil: 13%
Field studies of workers have shown that dermal absorption of PAHs may be
significant. Dermal absorption of PAHs, based on the urinary excretion of 1hydroxypyrene
(1-HP), has been documented among petrochemical industry
workers, including those digging in PAH-contaminated soil (Boogaard and van
Sittert, 1995). Although no attempt was made to quantify the extent of absorption
through dermal and inhalation routes, the results of the study strongly suggest
dermal uptake is substantial and is mitigated by the use of appropriate protective
clothing. Elovaara et al. (1995) compared the levels of urinary 1-HP among 6
creosote workers compared to that expected from the inhalation of the known air
levels of PAHs containing ≥ 4 rings. Higher levels of urinary 1-HP were observed
than could be accounted for solely from the inhalation route of exposure.
F. 4.3.1 Studies Considered
A. Key Study
In Wester et al. (1990b), the dermal uptake of soil-bound BaP was studied in vivo
in four rhesus monkeys. The systemic absorption of soil-bound BaP was based
on urinary excretion following exposure of 12 cm 2 abdominal skin to 10 ppm BaP
in soil at a soil loading of 40 mg/cm 2 skin. A nonocclusive cover protected the
dermal application site. Prior to sieving to approximately 180-320 µm diameter,
the soil composition was 26 percent sand, 26 percent clay, and 48 percent silt
with 0.9 percent organic carbon content.
Exposure duration to the chemical laden soil was 24 hours, during which time
urine was collected. The cover was removed, visible soil was collected, and the
skin application site was washed with soap and water. Urine was then collected
for 6 additional days for a cumulative recovery period of 7 days. Incomplete
excretion of BaP was corrected by the urinary excretion of BaP following
intravenous (iv) administration of the PAH in acetone. The authors report a
mean 24 hour dermal absorption factor of 13.2 ± 3.4 percent (Table F.4).
Radiolabeled BaP ( 14 C-BaP) was mixed with commercial gardening soil and
applied in vitro onto fresh human female breast skin (obtained within 1 day of
harvest) for 24 hrs by means of Bronaugh diffusion cells (Moody et al., 2007).
The same amount of 14 C-BaP was also applied without soil to human skin
samples. The soil had been sieved to