Bisphenol-A (BPA) is a synthetic chemical and a petrochemical derivative that was first used in 1957, most commonly as a hardening agent in plastics. Subject to ongoing controversies, questions about its safety continue to be raised in the face of reassurances from the corporate sector.
Xeno-oestrogens are endocrine-disrupting chemicals that mimic natural female sex hormones, misguiding cell development in dysfunctional ways.
A traditional basis of toxicology is that “the dose makes the poison”, which implies that the toxic risk diminishes as the dose drops. BPA challenges this assumption, its effects being stronger at lower levels that more closely approximate the concentration of hormones in the body.
BPA is hard to avoid, having recently been identified in the urine of 96 per cent of pregnant women in the US. In adults, it is generally metabolised within 24 hours but usually gets replenished on an ongoing basis via exposure from multiple environmental sources.
For babies, liver enzyme activity is only about 5 per cent of that of adults and mathematical modelling predicts that babies’ blood BPA levels are 11 times higher than those of an adult. Mother-to-baby transfer of the chemical has been identified.
Exposure has been linked to a range of elevated health risks, including:
- Male infertility
- Breast cancer
- Sexual dysfunction
- Heart disease
- Infant brain development concerns
- Child behavioural issues
According to the French food safety agency ANSES, risks from BPA appear to be disproportionately high for unborn children.
Both BPA and its sister chemical bisphenol-S have been detected in landfill leachate. When entering waterways, BPA can affect the appearance and behaviour of fish, leading to inter-species breeding that could impact biodiversity. In the US, the use of sewage sludge as a fertiliser is causing BPA residues to turn up in non-organic fresh produce.
For most of the population, canned food and drink are the primary sources of exposure. BPA is commonly found in both the white and clear inner linings that prevent metal from coming in contact with the contents. Being water-soluble, it readily migrates into food and liquids, an effect that’s more marked for acidic content such as tomatoes, tomato juice and canned soft drinks.
Tests carried out in 2010 by the Australian consumer group Choice detected BPA residues in 33 of 38 canned food products. Similar US testing has revealed that levels wary widely, even when comparing two identical cans made by the same company.
A couple of Swedish reporters recently carried out an experiment involving consuming nothing but canned food for two days. Their urine BPA levels were observed to increase by 28- to 46-fold. Other research has found that three days spent eating food that was neither canned nor packaged reduced BPA urine levels by 50–70 per cent. This further highlights the benefits of choosing fresh food over packaged and canned.
In response to the BPA controversy, a few food companies have opted to go BPA-free. These include Heinz, but only for its baby food range. American organic food company Eden Foods went BPA-free with its canned range in 1999 (with the exception of tomato products) by switching to baked-on oleoresinous C-enamel. The packaging cost rose by 14 per cent, amounting to US 2.2 cents per can (AUD 2.4 cents/NZD 2.6 cents).
Many people have been exposed to misleading information indicating that plastic bottles contain BPA. In reality, nearly all plastic water bottles are BPA-free. It is, however, widely used in polycarbonate products, such as water cooler jugs and refillable water bottles (recycling code 7), and in some PVC plastics (recycling code 3) as an antioxidant. Most controversially, BPA is found in some baby bottles and sippy cups. Many baby bottles are available now with the proud boast, “BPA-free”. Polycarbonate is also used for some microwave ovenware, cooking implements, mugs, and storage containers.
With repeated use, the BPA released from polycarbonate plastic tends to increase. In the US, the National Toxicology Program recommends minimising exposure by not microwaving food in plastic containers and not putting plastics in the dishwasher with harsh detergents.
Unfortunately, the problems associated with BPA seem to extend to most types of plastic. A 2011 study looked at 455 products made from plastics with recycling codes 1, 2, 5, 6 and 7 and found that 72 per cent demonstrated oestrogenic activity, with this proportion reaching 95 per cent after washing and microwaving. Not one single type of plastic tested received a relatively clean bill of health. The study’s authors suggested that plastic packaging could be cheaply reformulated to be xeno-oestrogen-free.
Another source of BPA is the thermal receipts issued by retailers and financial institutions. Low-level exposure begins as soon as a finger touches a receipt and is increased roughly 10-fold if the finger is wet or greasy. Recent tests among subjects handling receipts for two hours showed increased BPA levels in the urine, with gloves being effective at avoiding absorption. If you regularly touch receipts in your workplace, wear thin gloves if your workplace permits it.
As receipts rub against banknotes, BPA is transferred to money, especially in warmer climates. A recent survey of the notes circulating in 21 countries found that Australia had one of the three highest BPA levels. As a precaution, wash your hands after handling both receipts and money.
Both BPA and BPS are commonly used in receipts, so be cautious of “BPA-free” assurances. BPS has similar properties to those of BPA, has roughly the same level of endocrine-disrupting activity and is more persistent in the environment. Research has found that BPS may be 19 times better absorbed via the skin than BPA.
Thermal receipts are fully recyclable and, as a result, low concentrations of both BPA and BPS have been detected in recycled paper products, including toilet paper. It’s worth lobbying retailers to remove BPA and BPS from their receipts and to ask the Recycling Near You (recyclingnearyou.com.au) and Recycle.co.nz websites to add an update discouraging the recycling of receipts. On balance, it’s safer to throw them in the garbage.
Many holistically oriented people who are proactive about maintaining their health avoid mercury-containing amalgam fillings in favour of dental composite materials. Few are aware that about 90 per cent of these composite fillings contain a chemical known as bis-GMA, which leaches low levels of BPA into the body via the mouth.
In 2012, the New England Children’s Amalgam Trial found that children who received composite fillings containing bis-GMA had worse behaviour outcomes than those who received non-bis-GMA materials, including amalgams.
Some bis-GMA-free composites exist — details are fairly easy to track down online — and holistic dentists are more likely to use them. When looking at biocompatibility among dental materials, BPA is one among several factors to consider.
BPA can also show up in a number of other odd places, including:
- Aluminium drinking bottles (if it sticks to a magnet, it will be steel)
- Gasket seals for mason jars
- Cigarette filters and secondhand tobacco smoke
- Linings of plastic water pipes
- Bottle tops
- The inner layer of epoxy-coated water tanks
- The inner layer of epoxy-coated wine vats, and in the plastic bags inside some boxed wine
- Epoxy flooring and paints
Safety limits & scientific opinion
While the EU applies a 600 parts per billion BPA limit for food and drink, neither Australia nor New Zealand have set their own limit. An international Acceptable Daily Intake (ADI) is set at 50 micrograms (millionths of a gram) per kilo of bodyweight per day, although in January 2014 European authorities temporarily tightened their limit by a factor of 10, to five micrograms.
One of BPA’s strongest critics is Professor Frederick vom Saal at the University of Missouri in the US, who is extremely concerned about what he sees as BPA risks being covered up and ignored, given that some scientific studies are showing effects at very low concentrations.
Linda Birnbaum of the US National Institute of Environmental Health Sciences (NIEHS) is reporting seeing effects from BPA at the picogram (trillionth of a gram) level. Cutting-edge research underway in France, aided by a team from Australia’s Deakin University, has identified a powerful oestrogen receptor protein pathway in the body that is about a thousand times more potent than other similar receptors.
An international panel of 38 experts concluded in the Chapel Hill Consensus Statement that “The wide range of adverse effects of low doses of BPA in laboratory animals … is a great cause for concern with regard to the potential for similar adverse effects in humans.”
When the Milwaukee Journal Sentinel followed the BPA money trail in 2008, it concluded that the US Food and Drug Administration (FDA) had relied on industry lobbyists for data sources. The FDA’s evaluation of BPA was based on two industry-funded studies that relied on a breed of rat that was little affected by BPA, while one of the studies was described by researchers as having “fatal flaws”.
A 2005 review of scientific literature by Vom Saal showed that 109 of 119 government-funded studies (92 per cent) identified significant effects on rats and mice. Perhaps unsurprisingly, none of the 11 industry-funded studies that he examined uncovered harmful results.
Regulated … or not
In a 2010 report, the FDA expressed “some concern” about possible hazards from BPA to foetuses, babies and young children. Since then, it has backtracked and now claims the chemical is safe. This view is contradicted by other US agencies, including the Office of Women’s Health and the science-focused NIEHS.
On its website, Food Standards Australia New Zealand (FSANZ) says the “overwhelming weight of scientific opinion is that there is no health or safety issue at the levels people are exposed to”. A similar view is held by the New Zealand Food Safety Authority.
However, some other countries are taking a conspicuously different route. In 2010, Canada was the first country to declare BPA toxic and potentially harmful to health. Japan voluntarily replaced the BPA in food cans with PET film about 10 years ago and BPA (but not BPS) was banned from receipts.
For baby bottles and sippy cups, the use of BPA is currently prohibited in the EU and 11 countries including the US, Canada and China. In Australia and New Zealand, BPA in baby bottles is subject to a voluntary phase-out that began in 2010, and products with BPA have been removed by the large retailers.
France has been particularly proactive, with the country’s food safety agency ANSES advising pregnant women and young children to avoid BPA from all sources. In 2015, it will become the first country to ban BPA from food contact packaging and in the meantime requires a warning message on BPA-lined cans that reads: “Packaging made using bisphenol-A. Use not recommended for pregnant or breast-feeding women or for children under three.” France, Denmark, Belgium and Sweden have banned BPA from food containers intended for under-threes.
A plastic reality check
The BPA industry appears to be playing a delaying game to stave off the inevitable regulatory action. Strategies include negative industry-funded studies, aggressive lobbying and pro-industry websites such as BPA Coalition and Facts About BPA.
Compared to the US, where BPA is a major controversy, in Australia and New Zealand its continued presence is aided by a generally lazy mainstream media and by supermarkets and food companies that may be concerned about the small extra cost of BPA-free cans. In a weak regulatory environment, they are unlikely to budge except in response to consumer pressure.
While avoiding BPA and BPS is important, unfortunately “BPA-free” does not equate to “safe”. The problem of other xeno-oestrogens (including other bisphenols) in plastics is a priority issue and we will only be able to evaluate the alternatives when information is freely provided to consumers.
Our Stolen Future, ourstolenfuture.org
Martin Oliver is a writer and researcher based in Lismore, northern NSW, Australia.