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

160 CHAPIN ET AL.
referred to as 4,4 0 -isopropylidnediphenol. Polymers
manufactured with bisphenol A are FDA-approved for
use as anoxomers and in coatings, adhesives, single and
repeated food contact surfaces, and tooth shade resin
materials.
The European Union (2003) noted that resins, polycarbonate
plastics, and other products manufactured
from bisphenol A can contain trace amounts of residual
monomer and additional monomer may be generated
during breakdown of polymer. The American Plastics
Council reports that residual bisphenol A concentrations
in polycarbonate plastics and epoxy resins are generally
o50 ppm (S. Hentges, personal communication, October
30, 2006). Polymer hydrolysis can occur at elevated
temperature or extreme pH. An example of potential
human exposure is migration of bisphenol A from a food
container into the food. Exposure to bisphenol A through
food is discussed in detail in Section 1.2.3.2.
1.2.3 Occurrence
1.2.3.1 Environmental fate and bisphenol A levels in
environment: Bisphenol A may be present in the
environment as a result of direct releases from manufacturing
or processing facilities, fugitive emission during
processing and handling, or release of unreacted
monomer from products (European-Union, 2003). According
to the Toxics Release Inventory database, total
environmental release of bisphenol A in 2004 was 181,768
pounds, with releases of 132,256 pounds to air, 3533
pounds to water, 172 pounds to underground injection,
and 45,807 pounds to land (TRI, 2004).
Bisphenol A released to the atmosphere is likely
degraded by hydroxy radicals (European-Union, 2003).
Half-life for the reaction between bisphenol A and
hydroxy radicals was estimated at 0.2 days. It was also
noted that photolysis and photodegradation of bisphenol
A in the atmosphere is possible and photo-oxidation halflives
of 0.74–7.4 hr were estimated [reviewed in (Staples
et al., 1998; European-Union, 2003)]. The European
Union (2003) noted that because of its low volatility
and relatively short half-life in the atmosphere, bisphenol
A is not likely to enter the atmosphere in large amounts.
Removal by precipitation and occurrence in rain water
were thought likely to be negligible. Because of its short
half-life in the atmosphere, bisphenol A is unlikely to be
transported far from emission points.
Based on vapor pressure and Henry constant (Table 1),
the European Union (2003) and Staples et al. (1998)
concluded that bisphenol A is of low volatility and not
likely to be removed from water through volatilization.
Both groups concluded that hydrolysis of bisphenol A in
water is unlikely. However, there was disagreement on
potential for photo-oxidation of bisphenol A in water.
Based on physical and chemical properties, the European
Union concluded that photolysis of bisphenol A in water
is unlikely. Staples et al. (1998) noted that bisphenol A is
able to absorb ultraviolet light, especially in a basic
solution. Therefore, it was concluded that photolysis
from surface water is possible, depending on conditions
such as pH, turbidity, turbulence, and sunlight. Photooxidation
half-life of bisphenol A in water was estimated
at 66 hr to 160 days [reviewed in (Staples et al., 1998)].
Rapid biodegradation of bisphenol A from water was
reported in the majority of studies reviewed by the
European Union (2003) and Staples et al. (1998). A
biodegradation half-life of 2.5–4 days was reported in a
study measuring bisphenol A concentrations in surface
waters near the receiving stream of a bisphenol A
manufacturer [reviewed in (Staples et al., 1998)].
When the Staples et al. (1998) review was published,
soil sorption constants had not been measured but were
estimated at 314–1524. Based on such data, the European
Union (2003) and Staples et al. (1998) concluded that
bisphenol A adsorption to soils or sediments would be
‘‘modest’’ or ‘‘moderate.’’ Based on data for degradation
of bisphenol A in water, the European Union (2003)
predicted that bisphenol A would be degraded in soil
and estimated a half-life of 30 days for degradation of
bisphenol A in soil. Subsequent to the Staples et al. (1998)
and European Union (2003) reviews, a study examining
fate of 14 C-bisphenol A in soils through laboratory soil
degradation and batch adsorption tests was released by
Fent et al. (2003). In that study, 14 C-bisphenol A was
dissipated and not detectable in 4 different soil types
within 3 days. Soil distribution coefficients were determined
at 636–931, and based on those values, the study
authors concluded that bisphenol A has low mobility in
soil. The study authors concluded that bisphenol A is not
expected to be stable, mobile, or bioavailable from soils.
In studies reviewed by the European Union (2003) and
Staples et al. (1998), bioconcentration factors for fish were
measured at 3.5–68 and were found to be lower than
values estimated from the K ow. Both groups concluded
that potential for bioconcentration of bisphenol A is low
in fish. Higher bioconcentration factors (134–144) were
determined for clams [reviewed in (European-Union,
2003)].
Two studies examining aggregate exposures in preschool
age children in the U.S. used GC/MS to measure
bisphenol A concentrations in environmental media
(Wilson et al., 2003, 2006). In the first study (Wilson
et al., 2003), bisphenol A concentrations were measured in
air outside 2 day care centers and the homes of 9 children.
Bisphenol A was detected in 9 of 13 outdoor air samples at
o0.100–4.72 ng/m 3 (mean concentration 5 2.53 ng/m 3 at
day care centers; 1.26 ng/m 3 at home). In indoor air from
day care centers and homes, bisphenol A was detected in
12 of 13 samples at o0.100–29 ng/m 3 (mean concentration
5 6.38 ng/m 3 at day care centers; 11.8 ng/m 3 at
home). At those same locations, bisphenol A was detected
in all of 13 samples of floor dust at means (range) of 1.52–
1.95 (0.567–3.26) ppm (mg/g) and play area soils at means
(range) of 0.006–0.007 (0.004–0.014) ppm (mg/g). In the
second study (Wilson et al., 2006), bisphenol A concentrations
were measured inside and outside at least 222 homes
and 29 daycare centers. Bisphenol A was detected in 31–
44% of outdoor air samples from each location; concentrations
ranged from oLOD (0.9) to 51.5 ng/m 3 . Medians
were olimit of detection (LOD). Indoor air samples (45–
73%) contained detectable concentrations of bisphenol A;
concentrations were reported at oLOD (0.9)–193 ng/m 3 .
Median values were oLOD–1.82 ng/m 3 . Bisphenol A was
detected in 25–70% of dust samples; concentrations were
reported at oLOD(20) to 707 ng/g.Medianvalueswere
oLOD–30.8 ng/g.
A second U.S. study used a GC/MS method to
measure bisphenol A concentrations in dust from 1
office building and 3 homes and in air from 1 office
building and 1 home (Rudel et al., 2001). Bisphenol A
was detected in 3 of 6 dust samples (reporting limit
40.01 mg/extract) at concentrations of 0.25–0.48 mg/g
Birth Defects Research (Part B) 83:157–395, 2008