What Plastic Baby Bottles and Climate Change Have in Common
A simple mistake can derail the best planned experiments. But sometimes – just sometimes – such an error can lead to an even bigger discovery.
Sixty five is retirement age. AARP gets in touch when you turn fifty. But a woman only has to be thirty-five years old to receive the demoralizing designation "advanced maternal age." That's the age when the chance of producing genetically defective eggs starts to climb steadily, increasing the risk of Down syndrome and other debilitating or deadly conditions.
Dr. Patricia Hunt, a Meyer Distinguished Professor at Washington State University, has long wanted to understand why this happens. For more than fifteen years, though, much of her effort has been dedicated to teasing apart an even more complicated problem - the effect of common household plastics on our ability to produce normal, healthy pregnancies and babies.
It all started with a simple mistake. Hunt uses mice as experimental proxies for the men and women she's ultimately interested in helping. In the late 1990s, a new employee washed the plastic mouse cages and water bottles with the detergent intended for the floor. It took months to see the effect on the plastic - hazing, cracking, softening - but only a week to know something was very wrong.
Suddenly, mice that had an excellent track record of producing normal, healthy eggs were acting like they had the ovaries of a forty-five year old woman. Actually, it was even worse than that, so bad that Hunt initially thought they'd mixed up normal mice and genetic mutants prone to producing defective eggs. In the span of a week, the proportion of eggs that were genetically abnormal jumped from 1-2 percent to 40 percent.
After months of detective work, Hunt and her lab members confirmed that the damaged cages and water bottles were leaching bisphenol-A, or BPA, and that was causing the spike in eggs with genetic abnormalities. They then replaced all of their mouse-houses and even the mice that live in them, and set off in a new research direction. Almost twenty years later, she's still trying to nail down how plastic chemicals like BPA cause reproductive problems in animals, and whether we humans need to be worried about similar effects.
What may be most striking about Hunt's story is the fact that it's not unique. Hunt says that, among the first generation of plastics researchers, it's common to find scientists who entered the field by accident, when the effects of plastic made their other research impossible.
The findings of that first cadre of self-made plastics researchers have since attracted others to the field, but the explosion of research on the hormone-like activities of plastic chemicals, like BPA, has yet to coalesce into a clear picture of how they do what they do and how much of a risk they pose. Different labs get different results depending on how much BPA they give to their research subjects, how and when it's delivered, what food they're using, and the genetic background of the animals involved.
Making the leap from lab rats to humans adds yet another level of complexity and uncertainty. Studies have shown that the vast majority - ninety percent or more - of us, have detectable levels of BPA in our blood at any time. But just because something is there, doesn't necessarily mean it's a problem. It's extremely difficult to blame any particular health problem on any one chemical, when we're exposed to so many possible offenders all the time and our susceptibility to them varies based on everything from genetics, to diet, to where we live.
Hunt compares the plastic conundrum to climate change, saying that even though there's uncertainty about many of the details, there's solidly enough science to warrant concern and a serious conversation about how to address it. She shares her own concerns freely - with colleagues, parent groups, and legislators. Along the way, she's helped raise awareness about the possible dangers of plastic baby bottles and learned the power of her own words. Some might say that makes her an activist, for better or worse; she prefers to think of herself as a concerned scientist.