Bisphenol A

**Bisphenol A** (**BPA**) is an organic compound. It is a bisphenol, a type of compound with two linked phenol groups. The "A" stands for acetone, which is used to link the two phenols. BPA is an important commodity chemical, with billions of tonnes made every year. It is used to make many different types of plastic, mostly polycarbonates and epoxy resins.

BPA is controversial because of links to health issues. Scientists discovered in the mid 1930s that people and animals react to BPA in the same way that they react to hormones (with oestrogen-like effects). Some stores stopped selling products made with BPA in 2008 because government reports said BPA was not safe for humans. Many news stories wrote about BPA safety.

A 2010 report from the United States Food and Drug Administration said that contact with BPA could hurt fetuses, infants and young children. In September 2010, Canada became the first country to say that BPA was a toxic substance. In the European Union and Canada, BPA cannot be used to make baby bottles.

## Uses

BPA will react with other chemicals to make different types of plastic. The most common use of BPA is to make polycarbonate. In this reaction, BPA reacts with phosgene to make a long chain made of carbonate esters. Hydrogen chloride is made as a byproduct, so a base is usually added to neutralise it.

BPA is also used to make bisphenol A diglycidyl ether (BADGE). This reaction uses epichlorohydrin and a strong base like sodium hydroxide. BADGE is an ingredient in epoxy resin and other thermoset materials like vinyl ester resin.

The use of these plastics for bottles, plumbing, and canning means that contamination of food and drinking water by BPA is a public health problem. Because of this, people have started to use alternatives to BPA for food and drink containers.

## Health effects

Bisphenol A damages the way hormones regulate (control) the human body (endocrine disruptor). BPA can pretend to be the body's own hormones. BPA may cause health problems. Very young children are most sensitive to BPA. Some studies have shown that there is a link (connection) between BPA exposure before birth and later problems of the nervous system. Health organizations have decided how much BPA (in a substance) is safe for people. But new studies have caused other scientists and health organizations to disagree with these decisions.  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.

### Expert panel conclusions

In 2007, 38 experts on bisphenol A wrote a scientific consensus statement which said average levels in people are above those that cause harm to many animals in laboratory experiments.  However, the experts noted that 1) BPA is not persistent in the environment or in humans, 2) biomonitoring surveys indicate that exposure is continuous, 3) it is hard to use acute animal exposure studies to estimate daily human exposure to BPA, and 4) no studies that had examined BPA pharmacokinetics in animal models had followed continuous low level exposures. The measurement of BPA levels in human serum and other body fluids suggests that either BPA intake is much higher than previously thought or that BPA can bioaccumulate in some conditions such as pregnancy, or both.  A 2011 study, the first to examine BPA in a continuous low level exposure throughout the day, did find an increased absorption and accumulation of BPA in the blood of mice.

In 2007, 153 government-funded BPA experiments on lab animals and tissues found adverse effects and 14 did not.  In contrast,  all 13 studies funded by chemical corporations reported no harm. The studies indicating harm reported a variety of harmful effects in rodent offspring exposed in the womb: abnormal weight gain, insulin resistance, prostate cancer, and too much mammary gland development.

A panel convened by the U.S. National Institutes of Health in 2007 determined that there was "some concern" about BPA's effects on fetal and infant brain development and behavior. The concern over the effect of BPA on infants was also heightened by the fact that infants and children are estimated to have the highest daily intake of BPA. A 2008 report by the U.S. National Toxicology Program later agreed with the panel, expressing "some concern for effects on the brain, behavior, and prostate gland in fetuses, infants, and children at current human exposures to bisphenol A," and "_minimal_ concern for effects on the mammary gland and an earlier age for puberty for females in fetuses, infants, and children at current human exposures to bisphenol A." The NTP had "_negligible_ concern that exposure of pregnant women to bisphenol A will result in fetal or neonatal mortality, birth defects, or reduced birth weight and growth in their offspring."

### Other opinions

In 2009, The Endocrine Society said it was worried about current human exposure to BPA.

In 2011, the United Kingdom Food Standards Agency's chief scientist said "the evidence [is] that BPA is rapidly absorbed, detoxified, and eliminated from humans – therefore is not a health concern."

## Other websites

- Plastic Not Fantastic with Bisphenol A (www.scientificamerican.com)
- US FDA statement on bisphenol A from 2008

- Hazard in a bottle Attempt to regulate BPA in California defeated (from _The Economist_)
- Bisphenol-A News & Products  News commentary on BPA Containing Products

- How to Protect Your Baby from BPA (Bisphenol A)
- ChemSub Online : Bisphenol A.