Thought-provoking story describes alternatives to bisphenol A.
BPA is widely used in food can linings, and exposures through canned food are thought to be related to the frequency with which BPA is detected in the urine of the US population. This application of BPA has also proven to be one of the most difficult in terms of finding a substitute technology. The Washington Post article provides an excellent summary of the properties needed for high performance steel can linings and industry efforts to replace BPA-containing materials.
One of the most striking parts of the story is the revelation that one food company that switched to BPA-free steel cans is still finding trace amounts of BPA in its products. The source of contamination remains unknown. This adds to growing evidence that estrogenic chemicals are so widely used in manufacturing supply chains that it has become difficult to pinpoint how and where in the process they are able to migrate into food and drink. For example, a 2009 study found that bottled water showed estrogenic effects after it was stored in Tetra Pak liners. It is still unclear whether this was a result of the packaging materials themselves or some other aspect of the manufacturing process.
These findings suggest that our problems will not be solved just by replacing BPA in food can linings. As discussed in the Post article, BPA is used in thousands of consumer products, increasing the chances of cross-contamination. What's not mentioned, though, is that BPA is not the only estrogen mimic showing up in food. The problem is more systematic, begging the question, will the potential alternatives discussed in the story be any safer?
It is very difficult for a chemist sketching new molecules in a notebook to predict whether those structures will lead to a toxic product or a safe product. This has led to situations described by NIEHS director Linda Birnbaum as like "jumping from the fry pan into the fire" when it comes to substitutes, as she said in reference to alternative flame retardants.
A possible solution to this issue is greater cooperation between environmental health scientists and green chemists, who are seeking to better understand the connections between chemical properties and toxic endpoints. Progress in this area would make it easier to recognize chemical hazards as a design flaw.
The Post article did a good job bringing up difficult issues regarding chemicals in the food supply, and provided a rare focus on the quest for replacements. Other journalists could follow suit and begin asking more pointed questions that dig deeper into how chemicals can be made safer.