BPA: What, When, Where, How, Why
Bisphenol A, or BPA, has been recently thrust into the public spotlight because of its possible links to serious health issues. As you may know, Bisphenol A is a building block of polycarbonate plastic and it is everywhere. In fact, the chemical can be found in a slew of consumer products ranging from sports equipment to compact disks to baby formula. Chances are, the chemical is a big part of your everyday life. But what exactly is BPA? What is it made of? Where did it come from and what does it do?
Below are the basics of the chemical. The facts. The what, when, where, how and why of BPA.
What exactly is Bisphenol A?
Bisphenol A, commonly referred to as BPA, is a synthetic chemical compound. Many people are now aware that BPA is used to form a type of plastic. BPA is actually the key monomer used in the production of polycarbonate (PC) plastic and epoxy resin found in the lining of canned goods. PC plastic is hard and often shatter-proof. It is used in a wide range of consumer products such as water bottles, food storage containers, medical devices, CDs and baby bottles. Epoxy resin is found in the coating inside of almost all food and beverage cans.
What many people don’t know is that BPA mimics the hormone estrogen. It is what is known as an endocrine (or hormone) disrupting chemical. The endocrine system is the body’s finely tuned network of hormones and glands that control the development of the brain, the reproductive system and many other delicate systems.
Hormone disruptors (AKA endocrine disruptors), such as BPA, are substances that can interfere with the normal functioning of the hormone (or endocrine) system by duplicating, blocking or exaggerating hormonal responses. This can produce a wide range of adverse effects including reproductive, developmental and behavioral problems.
When was BPA invented and when did it become what it is today?
BPA was thrust into the limelight in the recent years but the chemical has actually been around for about 120 years. BPA was first synthesized by chemists in 1891.
BPA Timeline | Environmental Working Group
In the late 1930's, scientists discovered that BPA acted as an artificial estrogen. The estrogen impostor would have been used as a pharmaceutical hormone but a more potent synthetic estrogen called DES was invented, precluding the use of BPA. In what should have been a warning signal to the potential toxicity of BPA, DES was taken off the market when it was linked to reproductive cancers in babies born to mothers taking the chemical. (Decades later, similar toxic properties are being linked to BPA.)
The use of BPA in plastics would not take place for another twenty years. In the 1950's BPA began to appear in plastic consumer products throughout the world. For over 60 years, BPA has been used in the manufacturing of plastic without any law or regulation establishing its safety. In fact, although the Toxic Substances Control Act was passed by congress in 1976, it labeled BPA a "grandfather" chemical which means is was never evaluated and presumed safe by the Environmental Protection Agency.
There are seven classes of plastics. BPA is primarily found in polycarbonate plastics. It is also found in dental sealants and as an additive in other widely used consumer products. Some type seven (identified with the number seven within the recycling symbol) plastics, such as polycarbonate (which is identified with the letters PC near the recycling symbol) and epoxy resins are made with BPA. Polycarbonate plastics are used to make numerous consumer products including: baby bottles, sports equipment, compact disks, eye glass lenses, consumer electronics, medical equipment, and bicycle helmets. BPA-containing epoxy resin is used in almost every type of canned food in America. Some type three plastics (identified by the number three withing the recycling symbol) may also contain and leach BPA.
How does BPA find its way into our bodies?
BPA has been known to leach from plastics and can linings into our food and beverages. Studies have proven that heat (by microwaving, sterilizing, boiling or washing) accelerates this leaching. Researchers have shown concern that infants and children exposed to the chemical through re-usable baby bottles and baby formula are at a much higher risk to the adverse effects of BPA.
Why is BPA a concern?
As previously mentioned, BPA is a hormone disruptor that can interfere with the normal functioning of the endocrine system. It is also a building block of PC plastic, which is used in a slew of products that hold or are meant to hold food and beverages. BPA leaches from these products into our food and drink, exposing the population to the toxic chemical. Studies have linked BPA exposures, at low-dose levels, with a wide range of adverse effects including reproductive, behavioral and developmental problems.
Despite its dangers, however, BPA has been used in the manufacturing of PC plastic and can linings for over 60 years. The use of these plastics and lining today is incredibly widespread.
BPA is one of the highest-volume chemicals produced worldwide. In 2003 alone, over 6 billion pounds of BPA were used to manufacture PC plastic products, resin lining cans, dental sealants, and polyvinyl chloride plastic products. The ester bond linking BPA molecules undergoes hydrolysis, resulting in the release of BPA into food, beverages, and the environment. Human exposure to BPA is so widespread that a study conducted by the Centers for Disease Control and Prevention detected BPA in more than 93 percent of Americans.