For Hunt, this accident was particularly poignant: She calls it the second of two “lightning strikes” in her life. She is a DES daughter who had multiple abnormal Pap smears in her youth and is also a breast cancer survivor (cancer runs in her family, but there is also evidence that DES daughters get more breast cancer). “It’s very ironic,” Hunt explains. “BPA was studied as a synthetic estrogen in the 1930s and abandoned in favor of DES, which was more potent. Yet both of them found their way into my life. A lot of the abnormalities turning up in DES sons and daughters can be reproduced in mouse experiments. And that’s one reason I’m concerned about BPA. The effects we see in our mice are pretty significant,” Hunt says.
Hunt’s research on BPA and the fetal ovary shows that “one exposure can hit three different generations. It hits the mom, crosses the placenta, and affects the fetus, but it also affects that fetal ovary that is busy producing the eggs that will make the next generation. So the mom’s exposure is impacting the genetic quality of her grandchildren. We’re dealing here with multigenerational changes.”
Through studies like these, Jirtle says, “we’re beginning to understand how a molecule present at the very earliest stages after fertilization can in effect be remembered into your twenties and thirties and maybe give rise to diseases. You can’t do toxicology anymore without that insight.”
While chemists, biologists, geneticists, and toxicologists are piecing together the puzzle, some consumers have concluded they should simply try to limit exposure to plastics in their own lives. “But how do you do that?” asks Soto, who herself uses glass containers at home. “For instance, the milk you’re drinking was pumped through plastic tubes. And you can’t store milk in permeable paper cartons—they have plastic linings. Even if you try, you don’t know whether you’re limiting your exposure by 5 percent or 95 percent.” BPA has been found in drinking water, in 41.2 percent of 139 streams sampled in 30 states, even in house dust. Even if we could regulate BPA to levels that were safe, Soto cautions, “zero plus zero plus zero is actually not zero. By that I mean you can take 10 estrogenic chemicals at doses that on their own don’t have an effect, but if you add them together, you end up with problems. BPA is only one of many estrogenic chemicals in our environment.”
Krimsky favors legislation based on an entirely new way of thinking. “We should base legislation on two rules,” he explains. “One, if a synthetic chemical accumulates in your body and is not metabolized, let’s ban it unless we need it for survival. Why? On the precautionary notion that it can’t be good for the body to be a storage site for junk chemicals with no known physiological purpose. Two, if a chemical is biologically active and interacts with our receptors, it’s probably not good. Ban it. Maybe it’s OK in very small doses, but it’s going to take you 50 or 100 years to figure out those doses, if you can even do it. We put a human being in prison for life based on circumstantial evidence. Yet we’re looking for more than circumstantial evidence in order to ban these chemicals.”
Hunt and other scientists hope their research will catch the attention of the public even more so than industry or policymakers. “I’m struck by how fast companies respond to consumer demand,” Hunt says. “When our study broke in 2003 and the media came calling, I kept saying that what concerns me the most are baby bottles. They’re polycarbonate, and it doesn’t stand up well. I got a call from a baby bottle manufacturer one day, and he said, ‘What’s going on? We’re getting all these calls from consumers.’ And I was amazed to see how rapidly new polymers came on the market for baby bottles.” Indeed, sales of glass and non-polycarbonate baby bottles are rising. In turn, when consumers are charged for plastic bags at the supermarket, they tend to bring their own. Ireland’s “plastax,” launched in 2002, has resulted in a 90 percent voluntary reduction in plastic bag use. Finally, corn-based, biodegradable plastics are beginning to surface, and though these polymers are not yet as durable as current plastics, the technology is advancing.
“We have no choice,” Soto says. “If reproduction is being affected, the survival of the species is compromised. Sooner or later we have to regulate it. And what constitutes proof? In the 1950s a woman’s lifetime risk of breast cancer was 1 in 22; today it’s 1 in 7. A threefold increase cannot be genetic, it is most likely environmental, and many of us believe it is due to endocrine disrupters. To know whether fetal exposure to BPA is producing breast cancer in humans, you have to collect blood from the mother and the newborn, bank it, and follow that cohort for many, many decades. One generation of researchers can’t do it. This is painful, and the public should know about it.”
Determining the long-term consequences is difficult, because early exposure can have effects observed only much later in life.
