Eternal Source Blog

How are people exposed to BPA?

19/08/2011 at 11:26 am Leave a comment

It is hard to comprehend that in 2005 the US Centers for Disease Control & Prevention (CDC) found that 95 percent of Americans have detectable levels of BPA in their bodies[1]. Not only that, but in many cases these levels were found to be above the concentrations known to reliably cause adverse effects (like the ones discussed in a previous post) in laboratory experiments.

So the question is, how does BPA get into our bodies?

BPA leaching from Polycarbonate Plastics

BPA-based polycarbonate plastic products are thought to break down readily, particularly when heated or when washed with strong detergents.

For example,

• When we heat a baby bottle that contains BPA (on the stove or in a microwave) BPA is released into the contents of the bottle (like a baby’s milk or formula), which is then ingested.
• When we re-use a plastic water bottle or food container to the point where it is visibly scratched, or wearing down, BPA leaches into the contents inside, which we then ingest.

BPA leaching from the Epoxy Resins in Canned Foods

Some canned foods (like tinned fruits, vegetables, soft drinks etc) are lined with an epoxy resin that contains BPA.

This lining helps to protect the contents of the can from having contact from the actual metal the can is made from.

Studies have found that this epoxy resin can leach BPA directly into the contents of the can, although leaching normally occurs in cans containing liquids (like liquid vegetables, fruit, liquid baby formula etc) rather than dry contents (like powdered baby formula). For example:

• In March 2007 in the United States: the Environmental Working Group[2] found BPA in over half of the 97 cans of name-brand fruit, vegetables, soft drinks & liquid infant formula they tested in the United States. In some cases, the concentrations of BPA in a single serving were more than 200 times the government’s traditional safe level of exposure for industrial chemicals[3].

• In September 2010 in Australia, Choice tested 38 canned foods in Australia, including baby foods, baked beans, coconut milk, corn kernels, olive oil, spaghetti and tuna[4]. While none of the cans Choice tested contained BPA in excess of the EU’s limit of 600ppb, 33 of the 38 samples contained some BPA. In addition, Choice found that just one serving of 29 out of the 38 samples would give a 70kg adult more BPA than some experts believe to be a safe daily level of exposure. Its well worth looking at the full published list on Choice’s website.

BPA leaching from Thermal Paper in Shop Receipts

In October 2010, the Environmental Working Group conducted a study on BPA leaching from Shop Receipts in the United States and found that 2/5 of the paper receipts tested had been coated with BPA[5].

• Some of the major US retailers using BPA-containing receipts in at least some of their outlets included McDonalds, KFC, Walmart, Safeway & U.S. Postal Service.

While scientists have not yet determined how much of the BPA coating can transfer to human skin they are in the process of exploring what kind of exposure is likely through our skin and what kind of exposure is likely orally (as the BPA may transfer from our hands onto our food as we eat).

Other Potential Sources of BPA leaching

Scientists are also exploring other sources of potential BPA leaching & exposure, such as through drinking water (BPA has been found in some rivers and estuaries in the USA and therefore may be contaminating drinking water).

Studies are also being conducted in Japan and the USA about the impact of BPA leaching from landfills into surrounding ecosystems.

References:

[1] “Toxic Baby Bottles Report 2007″, Environment California, page 18.

[2] The Environmental Working Group is a non-profit environmental science research and advocacy group in Washington, D.C., United States dedicated to protecting public health and the environment.

[3] “A Survey of Bisphenol A in U.S. Canned Foods”, 5 March 2007, Environmental Working Group.

[4] “BPA in canned foods”, 1 Sep 2010, by David Oakenfull for Choice.

[5] “Synthetic estrogen BPA coats cash register receipts”, 2 November 2010, Environmental Working Group.

Entry filed under: Bisphenol A (BPA), Chemicals of Concern. Tags: BPA, Exposure to BPA.