Appendix D Food Codes for NHANES - OEHHA

Scientific Review PanelSRP Draft Version 2 February,June 2012
J.5 Summary and Recommendations
This appendix develops lactational transfer coefficients for use in estimating the
concentration of a multipathway chemical in mother’s milk from an estimate of
chronic incremental daily dose to the mother from local stationary sources.
OEHHA derived human lactational transfer coefficients from studies that
measured contaminants in human milk and daily intake from inhalation or oral
exposure (e.g. air, cigarette smoke or diet) in the same or a similar human
population. These coefficients can be applied to the mother’s chronic daily dose
estimated by the Hot Spots exposure model to estimate a chemical concentration
in her milk.
We established transfer coefficients (Tcos) for individual congeners and WHO-
TEQ summary PCDDs/Fs and dioxin-like-PCBs, individual and summary
carcinogenic PAHs, and lead through equations J-1-3, data on exposure and
breast milk contamination from background (global), accidental and occupational
sources, and a set of simplifying assumptions. We assume that a mother’s intake
and elimination is constant before lactation. We also assume that changes in a
woman’s body due to the onset of lactation occur as a single shift in elimination
rate over the lactation period. In some cases, OEHHA adjusted some
measurements of human milk and contaminant intake to account for confounding
factors. In such cases, OEHHA describes the method of adjustment in the text
and table containing adjusted values.
We described the methods for deriving specific Tcos from measurements of
human milk, intake and transfer estimates from studies of populations exposed to
general global sources of pollutants. Although the proportional contribution from
various exposure pathways to total exposure from a single Hot Spots facility is
likely to be quite different from exposure found with global sources, we believe
Tcos in this appendix have been derived from data that serve as reasonable
surrogates of transfer from Hot Spot facility exposures.
J.5.1 Dioxins and Furans
Personal factors such as body fat, smoking status and past lactation practices
can affect body burden and elimination rates. For example, smoking has been
associated with a 30% to 100% increase in elimination rates of some dioxin
congeners (Milbrath et al. 2009, Flesch-Janys et al. 1996). As well, the onset of
lactation sets a new elimination pathway into effect and can substantially reduce
the maternal body burden of PCBs during 6 months of lactation (Niessen et
al.1984, Landrigan et al. 2002).
Therefore, OEHHA incorporated conservative assumptions regarding these
factors into our model (i.e. reference half-lives based on body burden below 700
ppt in the blood, adult age, nonsmoker, no recent prior breast-feeding period and
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