Plastics, or Benjamin Braddock's Revenge

Naturalmom yesterday drew our attention to a lengthy article in the current issue of Discover, discussing the ubiquitous danger of plastics, which mimic estrogen and appear to be changing human genetics. It's very sobering reading, and worth excerpting at length. The gist of the piece is here:

Whereas lead exposure can be quantified by the drop in a child’s IQ and asbestos exposure can eventually be tallied by mesothelioma incidence, the typical standards of toxicology do not apply to the chemicals in plastic. If plastic harms, it does so by stealth: by mimicking our own hormones, by scrambling signals during development, by stimulating our own pathways excessively. And it may have that power at astonishingly low exposure levels, amounts that by typical toxicological measures look just fine. With plastic, less may be more, and a little may be a lot.

Phthalates are the chemical compounds used to make plastic soft. There's strong evidence indicating that they also biologically feminize male children:

If there is one point on which many scientists agree, it is the risk to the developing fetus and the young child. “At least a dozen studies have shown the effects of phthalates on human reproduction,” says University of Rochester epidemiologist and biostatistician Shanna Swan, the lead author of a much-cited study that showed higher exposure to some phthalates in mothers correlates with reduced “anogenital distance” in newborn boys. Biologists recognize a reduction in the length between the anus and the sex organ as an external marker of feminization, easily measured because it is typically twice as long in males as in females. The evidence on phthalates is strong enough for the European Union to have banned them in children’s toys, and last October California governor Arnold Schwarzenegger signed legislation, to take effect in 2009, setting stringent limits on the concentrations of phthalates in child-care products for children under age 3. The ban focuses on soft baby books, soft rattles, plastic bath ducks, and teething rings. Several other states are considering similar legislation.

BPA is another ubiquitous plastic that has been strongly linked to adverse biological effects -- and that has been found in higher concentrations in children. But it's so widely used, scientists say, that it's hard for people to grasp the magnitude of potential danger:

To shift public understanding on this issue is staggeringly difficult, especially given that exposure to plastic is not a matter of individual lifestyle. Unlike tobacco and lead paint, plastics are so useful we can hardly manage a day without them. Biologist Frederick vom Saal of the University of Missouri likens the issue to another colossal environmental threat. “This is the global warming of biology and human health,” he says.

The key thing to understand is that these substances do not act like normal toxins. Rather, they work by mimicking hormones. You would never think of giving estrogen pills to you children (male or female), but that's apparently what you do when you expose them to these substances. Which we all do, constantly, because we have little choice. This is the world we live in.

More:

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.”

Again: read the whole thing. I went into the kitchen last night and looked around to figure out how we could clear out these plastics ... and was overwhelmed by the difficulty of the task. And that's just the kitchen.