Something's in the air: BPA found around the world.

Sep 30, 2010

Pingqing F and K Kawamura. 2010. Ubiquity of bisphenol A in the atmosphere, Environmental Pollution 158:3138-3143.

A global study finds bisphenol A is in the air, showing yet another possible way people are exposed to the notorious endocrine disruptor.

Add air to the growing list of places where bisphenol A (BPA) is found, say a pair of Japanese researchers who have measured and reported levels of the chemical in the world's atmosphere. They discovered BPA in air samples from all over the world at widely varied levels – from almost nothing in remote areas near the poles to 10,000 times more than that in India and other heavily populated regions of Asia.

The results show the far reaching extent of BPA contamination and identify yet another likely source of exposure for people. Exposure is possible because researchers found that BPA floats in the air attached to particles that can infiltrate lungs. Still, the amounts of this exposure and any potential health risks from breathing the contaminated air are not known.

Researchers believe that BPA enters the air when plastics, electronics and other waste are burned, since the highest concentrations were measured near populated areas and coincided with high levels of other chemicals that are associated with burning plastics. BPA is a common ingredient in these types of products, and incineration is a popular way to dispose of this waste in certain parts of the world. Manufacturing processes for plastics and other consumer products containing BPA are also thought to be a major source of BPA in the air.

Controlling these emissions could limit worldwide exposure – especially in Asia – and could reduce any health effects associated from breathing it in, the researchers conclude.

Recently, much media attention has focused on the safety and health risks of exposure to BPA. The ubiquitous chemical has been measured in human blood, urine and umbilical cord blood, as well as in soil, water and dust.

Hundreds of scientific studies have linked BPA to health effects in animals. Rodents and monkeys exposed to BPA in the womb develop obesity, neurobehavioral and reproductive problems, and cancers of the prostate and mammary gland as they age. In humans, BPA exposure is linked to diabetes and heart disease in adults and behavioral problems in toddlers.  Another study linked high levels of BPA to sexual dysfunction in Chinese factory workers.

Because of concerns for the plausible health effects of BPA exposure, a few U.S. states, Canada and some European countries have restricted or banned the use of BPA in baby bottles or children's products, but widespread use remains.

Most human exposure is believed to occur through eating foods contaminated with BPA that seeps out of food and beverage can linings. BPA has also been detected in a range of paper products including cash register receipts, food-contact papers – like the kinds used for take-out food –  and paper towels. Recent studies indicate that the BPA in thermal and carbonless paper products can rub off onto skin where it can be absorbed or eaten. Inhaling or ingesting BPA-contaminated dust is also a potential way that it can get into people, especially toddlers.

In this unprecedented, multinational study, Japanese researchers Pingqing Fu and Kimitaka Kawamura reported on levels of BPA in 12 cities in India, China, Japan, New Zealand and the U.S.; two rural sites in China and Germany; eight marine areas in the Pacific Ocean, the Atlantic Ocean, the Indian Ocean, the Sea of Japan and the China Sea; and three polar regions in Canada and the Antarctic. They examined more than 260 samples collected when they cruised the world and used some previously recorded levels, most noteably a decades-old measure from the one U.S. city they included in the study. Comparisons for this city were limited due to the age of the reading.

The levels around the world varied wildly, depending on their distance from populated areas. Although levels in many Asian cities were high, levels in megacities Mumbai and Chennai in India were 10 times higher than those in China, Japan or New Zealand. The highest concentrations at the marine sites were found off the Asian coast.

BPA was also detected in the air at all three polar sites studied, although levels were much lower than samples collected elsewhere. Not surprisingly, the lowest levels of all were collected in Antarctica.

The authors suggest that the Asian continent is a strong source of BPA. BPA may be "emitted" from there and carried in the air for long distances by winds to other areas of the world, they propose. This is one reason they sampled air at the North and South poles.

There may be a silver lining, according to the researchers. If burning plastics are the main cause for the elevated levels of BPA in the air of some Asian megacities, simply eliminating the burning would be one way to significantly lower its levels in the atmosphere.