Appendix D Food Codes for NHANES - OEHHA

Scientific Review Panel Draft February, 2012
A. Key Study
The dermal uptake of each of the two commercial PCB formulations Aroclor 1242
and Aroclor 1254 was studied in vivo in female rhesus monkeys (Wester et al.,
1993b). Aroclor 1242 is dominated by the tri- and tetra congeners (68 percent)
and Aroclor 1254 is dominated by the penta- and hexa congeners (83 percent).
Each PCB preparation was adsorbed onto soil particles that before sieving
contained 26% sand, 26% clay, 48% silt, and 0.9% organic carbon. The soil was
fractionated by particle size to 180 - 300 µm. The soil levels of the PCB
preparations were 44 ppm Aroclor 1242 and 23 ppm Aroclor 1254.
The PCB laden soil was applied for 24 hours to a 12 cm 2 area of lightly shaved
abdominal skin which was protected by a non-occluded patch. The applied
doses were 1.75 µg/cm 2 Aroclor 1242 and 0.91 µg/cm 2 Aroclor 1254. The soil
loadings were 40 mg soil/cm 2 skin for both preparations. Following the first 24
hour exposure during which systemic absorption was measured as the content
recovered in urine and feces, the patch was removed, the visible soil was
removed from the site of application, the treated skin was washed with
soap/water, and urine/feces were collected for an additional 34 days. One group
of monkeys was exposed to the PCBs intravenously to adjust the cumulative
urine/feces recovery of the dermally applied PCBs. The corrected fractional
dermal absorption was 13.9% for Aroclor 1242 and 14.1% for Aroclor 1254.
B. Supporting Studies
PCBs are frequently found as complex mixtures of isomers in soil. To determine
the effect of chlorine substitution on dermal absorption, Garner and Matthews
(1998) applied dermal doses of 14 C-labeled mono-, di-, tetra-, and
hexachlorobiphenyls to 1 cm 2 areas on the backs of rats for 48 hrs. Dermal
penetration varied inversely with the degree of chlorination and ranged from
essentially 100% for monochlorobiphenyl to about 30% for the
hexachlorobiphenyl. However, the highly chlorinated PCBs tend to have slower
metabolism and elimination and remain in the site of exposure longer, resulting in
slow diffusion to the systemic circulation.
Mayes et al. (2002) dermally exposed female rhesus monkeys to radiolabeled
Aroclor 1260 in soil in a manner similar to that used by Wester et al. (1993b).
The soil was classified as sandy silt made up of 20% sand, 54% silt and 20%
clay with a total organic carbon content of 5-6%. Sieving to