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What is BPA and why is it bad for us?

Thankfully the media in Australia seem to have finally picked up on the dangers of manufacturing and using BPA plastic; which should in turn encourage people to become more informed & consumer savvy concerning the risks associated with BPA. But what exactly is it and why is it so bad for us, our children & our environment?

I have consciously tried not to use products that may contain BPA for several years now and this is part of the reason why I stock alternative high quality stainless steel and sustainable wood products within Fishica. But I have found it difficult to sum up why BPA is so dangerous and unnecessary…

A visit to the relevant Wikipedia page from where the bulk of the following information was taken found literally pages of information collated from a large number of sources world wide. The fact that there is so much information in itself seems to acknowledge how serious the issue is. While I have only selected bits and pieces to share here I encourage you to start reading yourself and follow the associated links that may help you understand in greater depth. In doing so I have little doubt you will be as horrified as I am and will want to take steps to ensure you, your family and friends have as little contact with BPA products as possible.

Bisphenol A, commonly abbreviated as BPA, is an organic compound with two *phenol functional groups. It is used to make polycarbonate plastic and epoxy resins, along with other applications.

(*Phenol definition: Phenol, also known as carbolic acid, is an organic compound. It is a white crystalline solid. The molecule consists of a phenyl (-C6H5), bonded to a hydroxyl (-OH) group. It is produced on a large scale (about 7 billion kg/year) as a precursor to many materials and useful compounds. It is only mildly acidic but requires careful handling due to its propensity to cause burns).

Known to be estrogenic since the mid 1930s, concerns about the use of bisphenol A in consumer products were regularly reported in the news media in 2008 after several governments issued reports questioning its safety, prompting some retailers to remove products containing it from their shelves. A 2010 report from the United States Food and Drug Administration (FDA) raised further concerns regarding exposure of fetuses, infants and young children. In September 2010, Canada became the first country to declare BPA as a toxic substance. In the European Union and Canada, BPA use is banned in baby bottles.

Use

Bisphenol A is used primarily to make plastics, and products containing bisphenol A-based plastics have been in commerce use since 1957. At least 8 billion pounds of BPA are used by manufacturers yearly. It is a key monomer in production of epoxy resins and in the most common form of polycarbonate plastic.

Polycarbonate plastic, which is clear and nearly shatter-proof, is used to make a variety of common products including baby and water bottles, sports equipment, medical and dental devices, dental fillings and sealants, eyeglass lenses, CDs and DVDs, and household electronics. BPA is also used in the synthesis of polysulfones and polyether ketones, as an antioxidant in some plasticizers, and as a polymerization inhibitor in PVC. Epoxy resins containing bisphenol A are used as coatings on the inside of almost all food and beverage cans, however, due to BPA health concerns, in Japan epoxy coating was mostly replaced by PET film. Bisphenol A is also a precursor to the flame retardant tetrabromobisphenol A, and was formerly used as a fungicide. Bisphenol A is a preferred color developer in carbonless copy paper and thermal paper, with the most common public exposure coming from some thermal point of sale receipt paper. BPA-based products are also used in foundry castings and for lining water pipes.

Identification in plastics

“In general, plastics that are marked with recycle codes 1, 2, 4, 5, and 6 are very unlikely to contain BPA. Some, but not all, plastics that are marked with recycle codes 3 or 7 may be made with BPA.”

There are seven classes of plastics used in packaging applications. Type 7 is the catch-all “other” class, and some type 7 plastics, such as polycarbonate (sometimes identified with the letters “PC” near the recycling symbol) and epoxy resins, are made from bisphenol A monomer.

Types 3 and 6 (PVC) can also contain bisphenol A as an antioxidant in plasticizers. This is particularly true for “flexible PVC”, but not true for PVC pipes

Some type 7 plastics may leak bisphenol A

Flexible type 3 plastics may leak bisphenol A


Health effects

Bisphenol A is an endocrine disruptor, which can mimic the body’s own hormones and may lead to negative health effects. Early development appears to be the period of greatest sensitivity to its effects, and some studies have linked prenatal exposure to later neurological difficulties. Regulatory bodies have determined safety levels for humans, but those safety levels are currently being questioned or under review as a result of new scientific studies. A 2011 study that investigated the number of chemicals to which pregnant women in the U.S. are exposed found BPA in 96% of women.

In 2009, The Endocrine Society released a statement expressing concern over current human exposure to BPA

Fetal and Early Childhood Exposures

Children may be more susceptible to BPA exposure than adults. A recent study found higher urinary concentrations in young children than in adults under typical exposure scenarios. This increased susceptibility is most likely based on their reduced capacity to eliminate *xenobiotics and also their estimated higher daily exposure to BPA, adjusted for weight, compared to adults.

(*Xenobiotic definition: A xenobiotic is a chemical which is found in an organism but which is not normally produced or expected to be present in it. It can also cover substances which are present in much higher concentrations than are usual. Specifically, drugs such as antibiotics are xenobiotics in humans because the human body does not produce them itself, nor are they part of a normal diet.)

Infants fed with liquid formula are among the most exposed, and those fed formula from polycarbonate bottles are particularly at risk. A 2010 study of people in Austria, Switzerland, and Germany has suggested polycarbonate (PC) baby bottles as the most prominent role of exposure for infants, and canned food for adults and teenagers. In the United States, the growing concern over BPA exposure in infants in recent years has lead the manufacturers of plastic baby bottles to stop using BPA in their bottles. However, babies may still be exposed if they are fed with old or hand-me-down bottles bought before the companies stopped using BPA.

One often overlooked source of exposure occurs when a pregnant woman is exposed, thereby exposing the fetus. Animal studies have shown that BPA can be found in both the placenta and the amniotic fluid of pregnant mice.  A small US study in 2009, funded by the EWG, detected an average of 2.8 ng/mL BPA in the blood of 9 out of the 10 umbilical cords tested. After the baby is born, maternal exposure can continue to effect the infant through transfer of BPA to the infant via breast milk. Because of these exposures that can occur both during and after pregnancy, mothers wishing to limit their child’s exposure to BPA should attempt to limit their own exposures during that time period.

While the majority of exposures have been shown to come through the diet, accidental ingestion can also be considered a source of exposure. One study conducted in Japan tested plastic baby books to look for possible leaching into saliva when babies chew on them. While the results of this study have yet to be replicated, it gives reason to question whether exposure can also occur in infants through ingestion by chewing on certain books or toys.

Other studies

Studies have associated recurrent miscarriage with BPA serum concentrations, oxidative stress and inflammation in postmenopausal women with urinary concentrations, externalizing behaviors in two-year old children, especially among female children, with mother’s urinary concentrations, altered hormone levels in men and declining male sexual function with urinary concentrations. The Canadian Health Measures Survey, 2007 to 2009 published in 2010 found that teenagers carry 30 percent more l bisphenol A (BPA) in their bodies than older adults. The reason for this is not known. A 2010 study that analyzed BPA urinary concentrations has concluded that for people under 18 years of age BPA may negatively impact human immune function. A study done in 2010 reported the daily excretion levels of BPA among European adults in a large-scale and high-quality population-based sample, and it was shown that higher BPA daily excretion was associated with an increase in serum total testosterone concentration in men. A 2011 study found higher BPA levels in women with polycystic ovary syndrome compared to controls. Furthermore, researchers found a statistically significant positive association between male sex hormones and BPA in these women suggesting a potential role of BPA in ovarian dysfunction. A 2010 study found that people over age 18 with higher levels of BPA exposure had higher CMV antibody levels, which suggests their cell-mediated immune system may not be functioning properly.

Sexual difficulties

A 2009 study on Chinese workers in BPA factories found that workers were four times more likely to report erectile dysfunction, reduced sexual desire and overall dissatisfaction with their sex life than workers with no heightened BPA exposure. BPA workers were also seven times more likely to have ejaculation difficulties. They were also more likely to report reduced sexual function within one year of beginning employment at the factory, and the higher the exposure, the more likely they were to have sexual difficulties.

Environmental risk

In general, studies have shown that BPA can affect growth, reproduction and development in aquatic organisms. Among freshwater organisms, fish appear to be the most sensitive species. Evidence of endocrine-related effects in fish, aquatic invertebrates, amphibians and reptiles has been reported at environmentally relevant exposure levels lower than those required for acute toxicity. There is a widespread variation in reported values for endocrine-related effects, but many fall in the range of 1μg/L to 1 mg/L.

BPA can contaminate the environment either directly or through degradation of products containing BPA, such as ocean-borne plastic trash.

As an environmental contaminant this compound interferes with nitrogen fixation at the roots of leguminous plants. According to Environment Canada, “initial assessment shows that at low levels, bisphenol A can harm fish and organisms over time. Studies also indicate that it can currently be found in municipal wastewater.”

A 2009 review of the biological impacts of plasticizers on wildlife published by the Royal Society with a focus on annelids (both aquatic and terrestrial), molluscs, crustaceans, insects, fish and amphibians concluded that BPA have been shown to affect reproduction in all studied animal groups, to impair development in crustaceans and amphibians and to induce genetic aberrations.

A large 2010 study of two rivers in Canada found that areas contaminated with hormone-like chemicals including bisphenol A showed females made up 85 per cent of the population of a certain fish, while females made up only 55 per cent in uncontaminated areas

Reference: http://en.wikipedia.org/wiki/Bisphenol_A