Appendix D Food Codes for NHANES - OEHHA

Scientific Review PanelSRP Draft Version 2 February,June 2012
from air to mother’s milk. Such improved data could allow for a robust
determination of the Tco values for individual compounds (see Table J.1-1).
Table J.1-1: Default Tcos ( d/kg) for Mother’s Milk
Chemical/chem.
group
Tco LCL UCL
PCDDs - oral 3.7 2.68 5.23
PCDFs - oral 1.8 1.27 2.43
Dioxin-like PCBs - oral 1.7 0.69 4.40
PAHs – inhalation 1.55 0.731 3.281
PAHs – oral 0.401 0.132 1.218
Lead - inhalation 0.064 0.056 0.074
LCL, lower 95% confidence interval of the mean Tco; UCL, upper 95%
confidence interval of the mean Tco
When calculating cancer risk from speciated PCDD/Fs, dioxin-like PCBs and
PAHs, assume that the ratios of congeners measured in the emissions are
preserved when transferred from the mother’s body to breast milk. OEHHA
recommends a single Tco for each chemical group (e.g. PCDDs oral). Risk
assessors can apply TEQs to the infant dose after applying the Tco for a
chemical group to each congener in the group to calculate infant cancer risk for
the mother’s milk pathway.
The mother’s exposure from multiple pathways should be included in estimating
the concentration of contaminant in mother’s milk. One key factor that plays a
role in the difference between oral and inhalation transfer coefficient (e.g., for
PAHs) is first pass metabolism which is lacking in dermal and inhalation
exposures. Thus, for simplicity, OEHHA applies the transfer coefficients from
inhalation to the dermal absorption pathway for lead and PAHs. For lead, we are
using the inhalation Tco for all the other pathways of exposure to the mother.
Likewise for PCDD/Fs and dioxin-like PCBs, we are using the oral Tco for the
other pathways of exposure to the mother in Eq. J-2.
J-50