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January 8, 2009

BPA controversy: What's in your water bottle?

Is your water bottle making you sick? What about the plastic container that holds the lunch you brought from home?

Among the most recent chemicals targeted for public concern is bisphenol A, an industrial chemical mainly used to make polycarbonate plastics and epoxy resins.

BPA is among a number of xenoestrogens (artificial compounds that mimic the effects of natural estrogens) counted as estrogen-disrupting chemicals.

Polycarbonate plastics are among those “other plastics” designated with a 7 in the triangular recycling code stamped on the product. However, not all plastics marked with a 7 contain polycarbonates. To be certain, consumers should look for further identification on the product package (such as “PC” for polycarbonate) or contact the manufacturer.

People can be exposed to BPA when it migrates from plastic containers into food or drinks, particularly during heating, or when it leaches from can linings. Babies are exposed to the chemical when BPA migrates into canned liquid infant formula or from polycarbonate baby bottles when boiling water is added to powdered formula.

As often is the case, even the scientists can’t agree about the safety of BPA, leaving consumers unsure whether they ought to be concerned.

A draft assessment by the U.S. Food and Drug Administration concluded last August that “an adequate margin of safety exists for BPA at current levels of exposure from food contact uses.”

But FDA’s own Science Board subcommittee on BPA, in its scientific peer-review of the draft assessment, disagreed. The subcommittee, which included Howard Rockette, chair of Pitt’s Graduate School of Public Health’s Department of Biostatistics, concluded that the margins of safety identified by the FDA may be inadequate.

The subcommittee, consisting of two members of the Science Board and five scientists from government and academia, disagreed with the FDA’s choice to exclude certain studies from its safety assessment and found, in part, that in light of other studies (and several published after the draft was completed) that the margins of safety may be “far less than those defined by FDA as ‘adequate.’”

In addition, the panel pointed out that the draft assessment did not examine cumulative exposures, noting: “The human health risks of the food contact applications may be understated when only a single source of exposure is considered and limited data are available regarding other food contact exposures,” such as those from polycarbonate “sippy” cups or sport bottles.

A report released last September by the National Toxicology Program (NTP) found that human exposure to BPA is of “some concern” for effects on development of the prostate gland and brain and for behavioral effects in fetuses, infants and children.

NTP, a research program at the National Institutes of Health’s National Institute of Environmental Health Sciences, uses a five-level scale ranging from “negligible” to “serious,” with “some concern” being the midpoint. In a prepared NIH release, NTP associate director John Bucher stated, “We are expressing this level of concern because we see developmental changes occurring in some animal studies at BPA exposure levels similar to those experienced by humans.”

In the same release, Michael Shelby, director of the NTP Center for the Evaluation of Risks to Human Reproduction, noted that more research is needed to understand how the findings relate to human health and development, “but at this point we can’t dismiss the possibility that the effects we’re seeing in animals may occur in humans,” adding that concerned parents can choose to reduce their children’s exposure to BPA.

In response to consumer concerns, some manufacturers and retailers already are turning to alternatives. Toys ‘R’ Us has announced it will phase out baby products containing BPA. Wal-Mart has stopped stocking baby products containing BPA in Canada and plans to phase them out this year in the United States.

“BPA-free” is turning up on more and more product labels. Tennessee-based Eastman Chemical Co. is marketing a BPA-free plastic called Tritan, which it touts as being compliant with FDA, European Union and Japanese Ministry of Health and Welfare food safety standards.

Sport bottle maker Nalgene and baby bottle producer Evenflo are among manufacturers that have turned to Tritan in light of consumer demand for BPA-free products.

James Fabisiak, a researcher in Pitt’s Department of Environmental and Occupational Health, pointed out that health risk controversies represent a two-edged sword: The public nature of the debate brings attention to the concern, but the intense focus on one chemical also can divert attention from other dangers.

That’s not to say public attention can’t yield positive effects on health, he noted, citing success in decreasing lead in the environment by legislating it out of gasoline and paint, thanks to public demand and ensuing government action.

“We have to be very careful of what we expose people to in food and the atmosphere,” Fabisiak said, cautioning however that “it’s always easier to show something is unsafe than safe.”

Changes may or may not represent an improvement. For instance, health concerns about butter prompted consumers to switch to margarine. Now trans-fats found in those alternative products are seen as bad.

He said the question becomes: Is the change that we make going to be more or less hazardous?

BPA is used in products ranging from food and drink containers to CDs and electronic equipment. A 2003-04 study by the Centers for Disease Control and Prevention (CDC) found some 93 percent of Americans have detectable levels of BPA in their urine. 

“Polycarbonate is used all over the place,” said Eric Beckman, a chemical engineer and director of the Mascaro Sustainability Initiative in the Swanson School of Engineering. Industry estimates put annual worldwide production of BPA at about 7 billion pounds, making BPA an economically significant product.

About 65 percent of BPA is used in the production of polycarbonate plastic. Some 30 percent is used in making epoxy resins, with the remaining 5 percent used in other products, Beckman said.

BPA polycarbonates have several attractive characteristics, he noted. Among them are high impact strength (some football helmets are made from them) and a softening temperature above the boiling point, which makes the material useful for medical equipment because the equipment can be steam sterilized without losing its shape.

Polycarbonates also are lightweight and transparent, which provides a cleaner look.

Other combinations of properties make polycarbonates the best material for use in CDs — although that’s becoming less important as iPods, memory sticks and drag-and-drop computer technologies are reducing the need for CDs, Beckman said.

Still, BPA is big both in its economic and environmental impact — emblematic of valuable but problematic chemicals, more of which are sure to be recognized as more sophisticated toxicological measurements are developed, Beckman said.

In addition to entering the food supply, BPA and other estrogen-disrupting chemicals can enter the water supply through leachate from landfills, discharges from wastewater treatment plants and sewer outflows, exposing fish and other wildlife to multiple chemicals that can affect endocrine function.

Endocrine disrupters have been associated with infertility; reproductive impairments; early onset of puberty; endometriosis, and breast, prostate, uterine and other cancers in humans and wildlife.

Research done by GSPH graduate student Maxine Wright-Walters in conjunction with faculty member Conrad Daniel Volz suggests that existing risk models may underestimate the risk BPA poses in aquatic environments. Their review of additional toxicity studies suggests that aquatic environments aren’t protected sufficiently from BPA’s effects at concentrations of 8 micrograms or less per liter established by earlier research.

The researchers say that suggests that the effects on aquatic creatures’ survival, growth, development and reproduction “may start to begin at extremely low concentrations that are environmentally relevant and have been reported in surface waters in China, Germany, Japan, the Netherlands and the USA.” (Additional information is available on the Pitt Center for Healthy Environments and Communities web site at

Although BPA isn’t known to accumulate in the body, more study is needed to examine the effects of long-term exposure, the researchers say.

Pitt’s Fabisiak recommends that consumers take a cautious, reasonable approach.

All chemicals can be toxic in certain concentrations, he noted. And evaluating the dangers can be complex.

Studying chemical mixtures that may be more indicative of actual exposures is difficult because such experiments are more unwieldy than those focused on a single substance, he said.

Timing also may make a difference, but it’s difficult to pinpoint for study, especially in humans. Exposure to a substance at a critical point in development might yield adverse impacts while no effect might be observed during other stages, he noted.

Accounting for other subtle contributors also can be hard to tease out, raising additional questions.

For example, a review using National Health and Nutrition Examination Survey data associated elevated urinary levels of BPA with higher rates of diabetes and cardiovascular events. But, is BPA the cause? Individuals differ widely, not only genetically but also in habit and lifestyle choices. Perhaps those with higher levels of BPA ate canned vegetables more than fresh vegetables. Were those who ate fresh veggies more health-conscious overall? By their lifestyles could they have been exposed to more BPA or to less? “It’s hard to know, particularly when you’re studying it years later,” Fabisiak said.

Concerned consumers need to educate themselves on where they may be exposing themselves to BPA and how they may avoid those exposures, Fabisiak said.

“I don’t think there are that many people getting sick from exposure to BPA,” he said. However, that’s not to say that people don’t need to be protected. “But who, and at what amount?”

Practically speaking, Fabisiak said, his rule is “don’t do anything to excess.”

Controlling the dose may be more practical than outright bans. “If the chemical industry and wastewater can be regulated to keep the dose low enough to be protected, it would be better than banning it,” he said. But, the question remains: How to find that safe dose?

On its web site, the FDA states that it believes FDA-regulated products containing BPA are safe and that exposure levels from food contact are below those that may cause health effects, a position it says is consistent with BPA risk assessments conducted by the European Food Safety Authority and the Japanese National Institute of Advanced Industrial Science and Technology.

“At this time, FDA is not recommending that anyone discontinue using products that contain BPA while we continue our risk assessment process. However, concerned consumers should know that several alternatives to polycarbonate baby bottles exist, including glass baby bottles,” the site’s BPA page states.

Likewise, while a Canadian government fact sheet on BPA stated that current research indicates BPA does not pose a health risk to the general public, uncertainty about the potential effects on infants and children has prompted the government to move forward with a ban on polycarbonate baby bottles. It also plans to establish maximum BPA concentrations in wastewater to limit release of the chemical into the environment and to work with manufacturers to reduce levels of BPA in infant formula. The Canadian government advised that adults do not need to quit using polycarbonate bottles, tableware or containers, but that those concerned about BPA migrating into food during heating may wish to switch to glass or other alternatives.

But are there good alternatives?

In a request for proposals for a recent round of seed grant funding, Pitt’s Mascaro Sustainability Initiative presented the development of alternatives to chemicals such as BPA as one research challenge related to sustainable design.

“We dangle ideas which fit our criteria,” said MSA director Beckman, adding that MSA seeks proposals for areas representing a “really big problem from a social and/or economic standpoint” in an area undersubscribed by researchers. “BPA fits the bill.”

The RFP acknowledged the existence of widely used chemicals such as PVC, brominated flame retardants, phthalates and bisphenol A that are sources of controversy due to the combination of high economic value and drawbacks such as human or ecological toxicity.

“Although off-the-shelf alternatives to these have been proposed, the alternatives typically do not match the original product in price and performance. There is a strong need to eliminate problematic high-volume chemicals from the environment through innovative design,” the RFP stated.

While MSI’s challenge found no takers, Beckman believes design should have a seat at the table when it comes to the development of chemical products.

“I don’t think a lot of design goes into the materials we use,” Beckman said, noting that many are accidents that were stumbled upon then optimized rather than being designed with intent and with attention toward alternatives.

“Design of alternatives typically isn’t thought about until you’re at the brink,” he said, noting that if an alternative is found “it’s going to be found as a crash course.”

That rush typically eliminates academia from participating. “We’re too slow,” Beckman said. “We’re the odd man out just when we’re needed most.”

Once a health issue arises in products that are in use, rather than discuss alternatives, “it becomes an argument,” he said.

The business and finance contingent argues that it will cost too much to change. Toxicology experts take the side that it would be too expensive not to change. “People that design things never get brought into the discussion,” he said.

Good alternatives should be “better, greener and cheaper,” Beckman said. When replacement materials are more expensive and don’t work as well, he said, his question to those designing them would be “Why did you stop?”

Beckman said one example of alternatives being designed came when chlorofluorocarbons (CFCs) were implicated in the depletion of the ozone layer. When the Montreal Protocol in the late 1980s set out a timetable for phasing out ozone-depleting materials, “people got serious about designing alternatives,” he said. Working on the problem starting with the molecular structure, then moving on to issues of performance and other characteristics, new generations of CFC alternatives have been designed.

“It’s an example of what you can do,” he said. “I wish you’d see that more often but you don’t.”

—Kimberly K. Barlow

Filed under: Feature,Volume 41 Issue 9

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