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Bisphenol A - what are the sources of exposure?

Friday, February 13, 2009

On January 28, 2009, Susanne Rust of the Milwaukee Journal Sentinel reported on a new finding that endocrine disruptor and suspected cancer-causing chemical Bisphenol A may stay in the human body much longer than previously thought, according to a study published in the journal Environmental Health Perspectives from Richard Stahlhut and Shanna Swan of the University of Rochester and Wade Welshons of the University of Missouri-Columbia, entitled "Bisphenol A Data in NHANES Suggest Longer Than Expected Half-Life, Substantial Non-Food Exposure, or Both".

BPA, a commonly used plastics chemical, leaches into food and beverage from polycarbonate plastic containers, epoxy can linings, and baby bottles. A year ago, scientists at the Centers for Disease Control and Prevention (CDC) analyzed the data from the National Health and Nutrition Examination Survey (NHANES) and discovered that BPA contaminates the bodies of 93% of Americans tested; women had higher BPA levels than men, and children and adolescents carried more BPA in their bodies compared to adults. Two key uncertainties were highlighted in the CDC study: what are all the sources for BPA exposure and how long this chemical would persist in the bodies of people of different ages.

BPA persists in the body The chemical industry and FDA have based their claims for BPA's safety to children on the assumption that this chemical has a short half-life in the body and is eliminated within 24 hours. However, when Rochester team re-analyzed the NHANES data in greater depth, they detected a new, startling finding that was previously missed: when a person abstains from food for 8-24 hours and thus avoids any food-based BPA exposure, BPA levels in their body drop off but never disappear. This persistence of BPA in the body may drive a lot of health risks, including breast cancer, diabetes and heart disease.

It's hard to reduce your exposure In 2008, Canada banned BPA use in baby bottles and took steps to minimize contamination of baby formula. Many states in the U.S. have been moving along the same path. In contrast, FDA has long stood in this issue on the side of the chemical industry, failing to protect the public from the health risks of BPA. Aggravated by the FDA's inaction, consumers have taken matters into their own hands, seeking out BPA-free products. Many manufacturers eagerly responded to the consumer demand and started offering BPA-free options. But is buying a BPA-free water bottle and avoiding canned food a sufficient measure for getting away from BPA exposure? Scientists were puzzled why bodies of so many Americans are polluted with BPA. Although plastics are ubiquitous in our society, not everybody is eating canned food and drinking water out of polycarbonate plastic bottles every day.

BPA exposures from new, unexpected sources As reported by the Journal Sentinel, "The research indicates for the first time that people are either constantly being bombarded with bisphenol A from non-food sources, such as receipts and plastic water piping, or they are storing the chemical in fat cells, unable to get rid of it as quickly as scientists have believed." The reference to receipts is fascinating - it is a little known fact that ordinary shopping receipts contain high levels of BPA, which smears on fingers and may end up being ingested or transferred into the body through the skin.

BPA contaminates much more than your body An estimated 6 billion pounds of BPA are produced globally annually, generating about $6 billion in sales. In addition to food containers, BPA is an additive in many other consumer products, some like plastic water pipes and municipal water storage tanks may also leach BPA directly into the drinking water. Let us also consider the other side of BPA lifecycle: What happens to those 6 billion pounds every year once they are released into the environment? They do not just disappear; on the contrary, BPA accumulates in the freshwater and marine environment, where it could damage wildlife reproduction. In 2007, an interdisciplinary team of scientists from seven different research institutions, found aquatic animals and aquatic ecosystems to be at great risk for BPA-caused endocrine disruption.

Water pollution with BPA is not just a risk to wildlife, as demonstrated by another research finding, this time from the U.S. Geological Survey (USGS). Tucked away among long data tables of a recent USGS report is a startling observation that BPA is 1 of the 5 most frequently detected chemical contaminants in groundwater sites analyzed by USGS. 30% of the samples tested by USGS scientists contained BPA. In many communities nationwide, groundwater is the main source of drinking water, and people in some communities might be continuously exposed to BPA simply from the water they drink. Water utilities have not been testing tap water for potential BPA contamination so we don't know how many people may be ingesting BPA with tap water. But just think about it: with 6 billion pounds of BPA produced every year, the purity of our water supplies may very well be at risk.

BPA is just one reason we need a new federal chemical policy The BPA debacle highlights the importance of looking before we leap, especially with respect to toxic chemicals. We need a watchful federal policy so that manufacturers would have to demonstrate the safety of their products before they are put on the market. This is why EWG supports the Kid-Safe Chemicals Act that would require that industrial chemicals be safe for infants, kids and other vulnerable groups. The old system of allowing chemicals on the market with minimal review is clearly broken and must be replaced with a new approach that would put human and environmental health ahead of manufacturers' profits.

Photo by jhhwild