Riverside Prenatal Biomonitoring Pilot Project:
Results for bisphenol A and parabens
June 2011 Report to the Community
What is the Riverside Prenatal Biomonitoring Pilot Project?
The Minnesota Department of Health conducted this project to measure certain chemicals in the urine
of pregnant women. Chemicals included environmental phenols, used in plastics and personal care
products, and cotinine, which indicates exposure to tobacco. This is a small pilot project, designed in
part to help MDH learn how best to do biomonitoring projects in the future. The project involved 66
women who participated in the Riverside Birth Study conducted by the University of Minnesota in 20092010 at Fairview Riverside Hospital.
What are environmental phenols?
Environmental phenols are chemicals used in plastics and personal care products. The phenols measured
in this study include bisphenol A (BPA) and four parabens: methyl, propyl, ethyl, and butyl paraben.
How are people exposed to BPA?
BPA is used to make hard polycarbonate plastics and epoxy resins. It is found in some plastic
containers and bottles (plastics marked on the bottom with a 7 may contain BPA) and in the
linings of most metal food and drink cans. People may be exposed to low levels when they eat
or drink from plastic containers that contain BPA, or from metal cans that contain BPA in the
lining. BPA has recently been found in cash register receipts and credit card slips. People may
be exposed when they touch the receipts.
How are people exposed to parabens?
Parabens are used as preservatives in foods and in personal care products such as shampoos
and cosmetics. More than one paraben may be used in the same product. People may be
exposed to low levels when they use a product that contains parabens on their skin or eat foods
that contain parabens.
Do environmental phenols harm people’s health?
Public awareness and media attention about possible health effects of exposure to BPA is increasing.
These concerns are based on studies in animals. While some of the animal studies raise concerns about
how low doses of BPA may affect the development of infants and young children, other studies indicate
that low levels of exposure to BPA are probably not harmful. But comparing research findings in animals
to health effects in humans can be difficult. Human studies are being conducted to explore possible
health effects, but we cannot say with certainty what any level of BPA measured in urine means for
human health. To help answer these questions, the federal government has launched a $30 million
research initiative on BPA.
Less research has been done on parabens. Some animal studies raise the concern that certain parabens
may affect the way the body responds to hormones, but it is not clear what this means for humans.
More research is needed.
Finding measurable levels of BPA or parabens in urine does not mean that these levels can cause a
health effect; it only tells us that the person was exposed to the chemicals.
What levels were found in pilot project participants? How do these compare to other studies?
MDH’s Public Health Laboratory analyzed the urine samples. BPA was detected in the urine of 56% of
women, methyl paraben in 94%, propyl paraben in 85%, ethyl paraben in 44%, and butyl paraben in 11%1.
Graph 1. Levels in urine of participants
Graph 1 shows levels of BPA,
methyl, and propyl paraben.2
Each participant’s level is
represented by a circle, and the
study average3 by a black line.
The average BPA level was 2.2
micrograms of BPA per gram of
creatinine ( g/g).4 BPA levels
were so low that they were
undetectable in some samples,
but as high as 47 g/g in one.
Methyl paraben averaged 73
g/g, ranging from undetectable
to 1158 g/g. Propyl paraben
averaged 14 g/g, ranging from
undetectable to 363 g/g.
Average levels for U.S. women in 2007-20085 are shown with a striped line in Graph 1 for each chemical.
Average BPA levels in Riverside project women were similar (2.2 compared to 2.4 g/g). Other studies
have measured BPA in pregnant women, with average levels ranging from 1.7 g/g in Cincinnati and the
Netherlands to 4.1 g/g in Norway.
Paraben levels were lower than the U.S. average (for methyl paraben, 73 compared to 126 g/g; for
propyl paraben, 14 compared to 22 g/g). Very few studies have measured parabens in pregnant women.
Because this was a small pilot project, we cannot conclude that these exposures represent all Minnesota
women. Also, BPA and parabens leave the body quickly after exposure, so results from one urine sample
show only the most recent exposure. Levels in a person’s urine can change based on time of day and
from day to day.
Do exposure levels show differences by income and racial/ethnic group?
Some studies have found that exposure to BPA and parabens differs by income level and race/ethnicity.
These differences may be due to available food options (eating more canned foods than fresh), cultural
dietary habits, targeted marketing of products (those containing parabens), or other factors.
1
These percentages depend on the limit of detection (LOD) for the chemical analysis – the level below which results cannot be
reliably measured. The LOD for all chemicals was 1 microgram per liter of urine. Because other studies have different LODs, the
percentages cannot be compared directly.
2
Figures do not include ethyl and butyl paraben (detected in < 50% of women).
3
The averages shown are geometric means.
4
Levels are adjusted by creatinine, a waste product found in urine. This is a common way to account for dilution of the urine sample.
5
Levels measured as part of the National Health and Nutrition Examination Survey.
2
Graph 2. BPA by income and race/ethnicity
As Graphs 2 and 3 show, the Riverside
Project also found differences in
exposure to these chemicals by income
level and race/ethnicity: levels of BPA
and methyl paraben were highest in the
lowest income group. Because of the
small number (n) of women in some
groups, we cannot say for sure what
these differences mean. BPA, methyl,
and propyl paraben levels were higher in
non-white women than white women.
Methyl paraben levels were 3½ times
higher in non-white than white women.
Graph 3. Parabens by income and race/ethnicity
The small size of the pilot project meant
that we had to combine all non-white
racial/ethnic groups, including people
who self-identified as Black/African
American, Hispanic, Asian, and other
groups. Future studies should be larger
and should include more participants
from non-white racial/ethnic groups.
What can I do to avoid exposure to environmental phenols, both for myself and my family?
Chemical
Bisphenol A
(BPA)
How to reduce exposure
Avoid using plastic containers with the number 7 on the bottom. Throw away bottles
and cups that are scratched or cloudy if they contain BPA. Do not heat foods or
liquids in plastic containers containing BPA.
Where possible, use fresh or frozen fruits and vegetables or food packaged in glass
jars instead of canned food. Knowing which brands of canned food may contain BPA
is difficult; search the Web or contact manufacturers to find more information.
As of January 2009, the six major makers of baby bottles and infant feeding cups no
longer use BPA. In January 2011, Minnesota banned the retail sale of these products
containing BPA. To make sure a bottle or cup is BPA-free, read the label or contact
the manufacturer. If you are not sure, do not store or heat milk or formula in it and
throw it away if it is scratched or cloudy. If you feed your infant formula, choose
powdered rather than liquid formula.
Parabens
Read the ingredient lists of personal care products, such as hair gel, face creams, lotions,
shampoos, and bath products, and avoid those containing parabens. Other names for
parabens are methyl p-hydroxybenzoate and methyl parahydroxybenzoate. Most major
brands of deodorants and anti-perspirants in the U.S. do not contain parabens.
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Should I breastfeed my baby?
Breast milk is the best food for babies. While environmental phenols can be passed to a baby through
breast milk, the levels are typically very low. The benefits of breastfeeding far outweigh any risks from
exposure. If you express your breast milk for your baby to drink by bottle, do not store or heat the milk
in bottles that contain BPA. See “How to reduce exposure,” above.
What public health actions are being taken to reduce exposure of the public to environmental phenols?
Based on the uncertainty about health effects of BPA, some states have passed precautionary laws to
reduce BPA exposure in infants and children. In Minnesota, the retail sale of baby bottles or baby cups
containing BPA became illegal on January 1, 2011. In addition, MDH developed a list of Priority
Chemicals as part of the 2009 Toxic Free Kids Act which includes BPA. Other states (Maine and
Washington) with similar lists have required manufacturers to report products containing the listed
chemicals. At the same time, some manufacturers and retailers have voluntarily phased out using BPA in
their products.
Where can I get more information on reducing exposure to environmental phenols?
MDH Community and Family Health Division, “Baby bottles, breastfeeding, and BPA: Information for
parents and caregivers”: http://www.health.state.mn.us/divs/fh/mchatf/documents/bpafactsheet.pdf
MDH Environmental Health Division, Web page on BPA:
http://www.health.state.mn.us/divs/eh/risk/chemhazards/bisphenola.html
U.S. Department of Health & Human Services, “BPA information for parents”:
http://www.hhs.gov/safety/bpa/
MDH Office of Statewide Health Improvement Initiatives, Web page on nutrition/access to fresh
food: http://www.health.state.mn.us/nutrition
For more information, contact the Environmental Health Tracking
and Biomonitoring Program at the Minnesota Department of Health.
Call: (651) 201-5900 or (800) 205-4987
Email: [email protected]
Visit: http://www.health.state.mn.us/tracking
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