Monograph on the Potential Human Reproductive and ... - OEHHA

174 CHAPIN ET AL.
Table 11
Bisphenol A Exposure Estimates by the European Commission a
Type of food and amount Concentration of bisphenol Exposure estimate (mg/kg
Age (body weight) consumed A in food (mg/kg) bw/day)
0–4-month old infant (4.5 kg) 0.7 L of formula/day 10 1.6
6–12-month old infant (8.8 kg) 0.7 L of formula/day 10 0.8
6–12-month old infant (8.8 kg) 0.38 kg canned food/day 20 0.85
4–6-year-old child (18 kg) 1.05 kg canned food/day 20 1.2
Adult (60 kg) 1.05 kg canned food/day 20 0.37
Adult (60 kg) 0.75 L wine/day 9 0.11
a European Commission (2002).
European Union (2003). Products included: marine
antifouling agents used on boats, wood varnish, wood
fillers, and adhesives. With the exception of adhesives for
which frequent use was thought possible, exposure to the
other products was considered to be relatively rare.
Exposures were estimated based on factors such as epoxy
and residual bisphenol A concentrations, exposure time,
area of skin exposed, and possible generation of mists
during processes such as brushing. Inhalation exposures
by product were estimated at 3 x 10 -4 mg for antifouling
agents and 0.02 mg for wood varnish. Dermal exposure by
product without protective clothing was estimated at
29 mg for antifouling agents, 3.6 mg for wood varnish, 9 mg
for wood filler, and 14 mg for adhesives. [Dermal
exposure to adhesives appears to be incorrectly reported
as 1 lg in Table 4.20 of the European Union
review.] Exposure was estimated to be 1–2 orders of
magnitude lower when protective clothing such as
gloves was used. Assuming an absorption rate of 10%,
dermal exposure to bisphenol A through adhesives was
estimated at 0.02 mg/kg bw/day.
The European Commission, 2002) reviewed the report
by the European Union (2003) in draft and suggested
alternate exposure estimates. Those estimates and the
assumptions used to support those estimates are summarized
in Table 11.
Miyamoto and Kotake (2006) estimated aggregate oral
and inhalation exposure to bisphenol A in Japanese male
children and adults. The estimates were based on
unpublished Japanese data. This report is the only
known study investigating potential exposure to children
through mouthing of toys. Mouthing times were estimated
by surveying the mothers of 50 infants and
recording 25 infants on video camera. Mean7SD daily
mouthing times were reported at 41.7713.7 min for
infants 0–5 months of age and 73.9732.9 min for infants
6–11 months of age. Migration rates were estimated from
0 mg/cm 2 /min for toys that do not contain bisphenol A to
0.0162 mg/cm 2 /min, the highest value reported in the
Japanese literature. It was assumed that most toys were
not manufactured with polycarbonate, epoxy resins, or
grades of PVC that contain bisphenol A. Surface area of
toys was assumed to be 10 cm2. In estimating oral
exposures to bisphenol A, intake from food was also
considered. Bisphenol A concentrations measured in
migration testing of polycarbonate bottles and food
surveys are summarized in Section 1.2.3.2. Volume of
food consumption and frequency of article use were
considered in estimates of bisphenol intake through food.
Bisphenol A concentrations in drinking water were
considered to be 0–0.17 mg/L, and water intake was
assumed to be 2 L/day. In estimating inhalation
exposures, concentrations of bisphenol A were considered
to range from 0–8.1 ng/m 3 in indoor air and 0–
28 ng/m 3
in outdoor air. Time spent indoors and
outdoors and breathing rates were considered. Absorption
from lungs was assumed at 100%. Estimated
exposures from mouthing of toys, food and water intake,
and inhaled air are summarized in Table 12.
Additional estimates of bisphenol A exposure through
food are summarized in Table 5 and Table 6. Details of
studies conducted by Earls et al. (2000) and Onn Wong
et al. (2005) are presented in Section 1.2.3.2. Exposure
estimates conducted by the FDA are described below.
Limited details were available from the other studies that
were presented in reviews.
The FDA (1996) estimated bisphenol A intake in
infants and adults resulting from exposures to epoxy
food-can linings and polycarbonate plastics. Exposure
estimates occurring through contact of formula with
polycarbonate bottles were based on results of a study
conducted by the Chemistry Methods Branch of the FDA.
The Chemistry Methods Branch also measured concentrations
of bisphenol A in 5 brands of infant formula (14
samples total); the study is also published as Biles et al.
(1997a). In estimating adult bisphenol A exposure
through the consumption of canned foods, the FDA
considered surveys conducted by the Chemistry Methods
Branch, Brotons et al. (1995), and the Society of
Plastics Industry Group. It appears that the study by the
Society of Plastics Industry Group was later published by
Howe et al. (1998) and included a re-analysis to correct
some interferences observed in analytical methods.
Exposure estimates and assumptions used to make the
estimates are summarized in Table 13.
Table 14 summarizes exposure estimates for aggregate
or food exposures. Studies suggest that the majority of
bisphenol A exposure occurs through food and that
environmental exposures do not appear to substantially
affect total exposure, with the possible exception of
exposure near point sources. Table 14 includes estimates
that CERHR believes to represent potentially realistic
exposure scenarios and does not include data from
extreme worst-case scenarios such as possible point–
source exposures.
1.2.4.1.2 Estimates based on biological monitoring: Goodman
et al. (2006) noted that total urinary bisphenol A
concentrations were useful for estimating bisphenol A
intake. Because of extensive first-pass metabolism, little
parent compound is systemically circulated, as discussed
in more detail in Section 2. Because nearly 100% of an
acute exposure to bisphenol A is excreted in urine within
Birth Defects Research (Part B) 83:157–395, 2008