Breasts (20 page)

The most common flame-retardant found in human breast milk is a mixture known as “penta-BDE,” which was until 2004 manufactured by the Great Lakes Chemical Corporation based in West Lafayette, Indiana. The company was making over twenty million pounds of it per year, most of it to drench flexible poly
urethane foam. In 2004, however, the European Union banned this substance and another called “octa-BDE” (the names refer to how many bromine atoms bond to carbon rings in the molecule), concluding they were likely to be “chronically toxic in humans.” For its part, the U.S. government instituted a voluntary phase-out in production but allowed foam manufacturers to continue to use large existing stockpiles. Another compound, “deca-BDE,” is set to be phased out beginning in 2013, but a major replacement, decaethane, is almost identical in structure. Most of us will continue to be sitting on and ingesting PBDEs and their chemical cousins for a long, long time.

WHEN ARNOLD SCHECTER CALLED WITH MY PBDE RESULTS, HE
had mixed news. The “good” news in relative terms was that at 36 parts per billion, my levels were only two points above the U.S. median. This means that roughly half of women tested had levels above mine and half below. The bad news was that my levels were presumably higher before I nursed my first child, and they were still many times higher than those of the rest of the industrialized world. What this meant, though, in absolute terms, remained unclear.

We knew that in rats, PBDEs bind to thyroid transport proteins and interfere with proper brain growth. “The most sensitive health endpoint is the harm done during development of the fetus and child,” said Tom McDonald, then of the California Office of Environmental Health Hazard Assessment. “We’ve seen irreversible and permanent behavior in the learning abilities and memory in rats and mice. At low doses, quite frankly, we’ve seen effects to the reproductive organs and delays in puberty. If you look at tissue
concentrations, the levels [of PBDEs] in some people are comparable right now.”

Based on the limited bio-monitoring tests done so far, it appears that 5 percent of the general U.S. population may have unusually high levels of flame-retardants in their bodies for reasons nobody understands. Their levels, over 400 parts per billion, correlate to the levels at which harmful effects are seen in lab animals. Several recent animal studies indicate that PCBs and PBDEs may act in unison to block protein receptors and affect thyroid and endocrine functioning.

When I first started writing about PBDEs six years ago, we knew little about their health effects in humans. But since then, the compounds have been better studied, and the results have not been reassuring. In humans as well as rodents, they are believed to interfere with thyroid hormones. These, in turn, play a strong role in brain development and the regulation of metabolism, ovulation, the menstrual cycle, and fertility. You don’t want to monkey around with a nursing baby’s thyroid. In 2010, researchers in New York found that babies and toddlers with the highest PBDE levels scored lower on tests of mental and physical development, including verbal and performance IQ.

In adults, low thyroid levels—which I happen to have—have been linked to breast cancer. A recent study found that California women were 30 percent less likely to become pregnant in a given month for every tenfold increase in blood PBDE level. The authors concluded, “Because exposure to PBDEs is ubiquitous in industrialized nations, even small decreases in fecundability may have widereaching public health impacts.” Males may be affected as well. A Danish study showed an association between PBDE levels and the
incidence of male genital birth defects and lower birth weights. None of this bodes well for infant exposures.

To learn more about the recent science, I attended an international conference in San Antonio, Texas, called simply “Dioxin.” The weeklong meeting, which convenes annually, is devoted to sharing the latest data on POPs, or persistent organic pollutants, including but not limited to halogenated flame-retardants. All POPs have as their defining characteristics a long life, widespread distribution, and well-established toxicity. Today we all live in the same chemical ocean with better and worse eddies. Not only do many synthetic substances accumulate up the food chain, but also they move great distances, carried by rain, wind, snow, and ocean currents. Lest you doubt these chemicals are everywhere, the conference sessions included such titles as “Flame Retardants in the Serum of Pet Dogs,” “Evaluation of Human Toenail as a Non-invasive Biomonitoring Matrix for Assessing Human Exposure to Environmental Organic Pollutants,” and “Human Exposure to Fluorinated Ski Wax.”

After a mariachi band played a welcome, I cornered Linda Birnbaum, the director of the National Toxicology Program at the National Institute of Environmental Health Sciences. Birnbaum is a bureaucrat, but she’s respected for her forthright views. I asked her if she believes people are harmed by flame-retardants. “Because we are all exposed on a continual basis, they will cause problems for some people,” she said. “We all have different vulnerabilities: age, genetics, pesticide exposure, co-exposures, or cross-exposures. Our old way of looking at these things is one chemical at a time and that doesn’t protect us.” We are the sum of our chemicals.

If POPs are so bad for us, wouldn’t we already be seeing a rise in the number of people with related health effects? Birnbaum said we might be seeing exactly that. She cited a rising prevalence of
thyroid disorders, infertility, and learning and behavior problems. Although we don’t know exactly what has triggered these problems, Birnbaum says chemicals like halogenated flame-retardants “will eventually build up to levels of concern, and we need to monitor and reduce them,” she said.

She does not go so far as to suggest women stop breast-feeding. But since we’ll be living with these substances for a good long while, it’s certainly a reasonable question for women in industrialized countries to consider. To answer it, it’s important to have some perspective. Breast milk is, after all, just one source of these chemicals for the baby. If they exist in milk, they exist in blood, and the infant’s first and arguably most significant exposure takes place across the placenta during fetal development. Another huge exposure takes place in the home, just by lollygagging around, crawling on the carpets, sucking on fingers, and orally exploring the (flameretarded) world. My kids thought cell phones and remote controls were pacifiers. Although it is known that breast-fed infants and toddlers have considerably higher levels of the chemicals in their bodies, their formula-fed peers catch up by mid-childhood.

Then there is the argument that breast-feeding may actually protect infants from the effects of chemicals, even as it is exposing them. Some studies have found that breast-fed babies develop better despite the additional chemicals found in breast milk, which is why the World Health Organization and other groups continue to recommend breast-feeding even among the Inuit, whose breast milk could technically qualify as hazardous waste.

Some lactivists are reluctant to highlight breast-milk contamination because they don’t want women to have yet another excuse not to breast-feed. This may be a real concern, but in a long history of such behavior it comes across as yet another condescending
way to treat pregnant or nursing women. We’ll tell you what you need to know! Trust us! When a California state senator proposed a statewide breast milk bio-monitoring program a few years back, an activist group opposed it, citing fear among mothers.

Yet breast milk is both a real reflection of our body burdens and a powerful symbol of contamination. “We test breast milk because it is a big sample with a lot of fat, it’s chemical-rich, and it’s noninvasive,” California’s Hooper told me. “We should be searching for fetal contaminants, and breast milk is the easiest way to look for them. It’s a direct reading of what the fetus is getting.” And let’s face it, breast milk carries some political weight. It was not until persistent organic chemicals began appearing in human milk that countries took steps to ban them. “Clearly breast milk speaks louder than sediment,” Hooper said. “When breast milk speaks, people listen.”

But despite the reassuring arguments to just keep breast-feeding, I find myself unsettled. The amount of chemicals that infants suckle through milk isn’t insignificant. Recent studies show that lactating mothers off-load about 2 to 3 percent of their total PBDE body burden per month to their offspring, or about 30 percent if they nurse for a year. I nursed both of my kids for eighteen months, and now I can’t help but wonder if that was such a great idea. For other chemicals, the dump rate is even higher, with a range of up to 14 percent per month for dioxins and up to 8 percent per month for PCBs. (I know I had these substances in my milk as well, because we tested them for good measure. Sorry, kids!) Mothers who breast-feed for a year also siphon off to their infants 90 percent of their body burden of perfluorinated compounds, known as PFCs. Used in the manufacture of products such as Scotchgard, GORE-TEX, and Teflon, PFCs have spread across the globe, even ending up in polar bear tissues, and they virtually never break down in the environment. An
EPA panel concluded one type of PFC called PFOA was “likely to be carcinogenic in humans.”

Lately, the industrial world’s enthusiasm for breast-feeding is being somewhat and very carefully modulated. As I learned at the Dioxin conference, the Norwegian Scientific Committee for Food Safety is currently debating that country’s breast-feeding recommendations, a fact that would have been unthinkable a decade ago. “I don’t think it will change the current recommendations, but maybe there’s no benefit to breast-feeding after six months,” Cathrine Thomsen of the Norwegian Institutes of Public Health told me. Consider the gravity of this statement. Norway has the single highest breast-feeding rate in the world, with 99 percent of new mothers doing it. At six months, more than half of all babies are still nursing. The country has actually banned advertising by formula companies. It grants paid maternity leave for forty-two weeks. This is a country deeply committed to breast-feeding. And now it is rethinking it.

In Sweden, as Åke Bergman, a respected researcher there told me, “there is now a strong recommendation that women not lose weight during nursing,” because that further mobilizes the contaminants in her fat and sends them into her milk. “It is like upending the candy bowl,” he said, with the brightly colored candy being the POPs nestled in and among our fat cells. If you’re scratching your head because you’d heard that losing weight was part of the point of breast-feeding, you’re not alone. The old rules no longer apply.

Thankfully, our overall levels of these compounds are still quite low. But one can almost imagine a grim sci-fi future in which firstborns are sacrificed or discarded like bad first pancakes. Incredibly, this may already be happening in marine mammals. Adult female striped and bottlenose dolphins are actually the “pur
est” of all, because they have so effectively dumped (the technical word is
depurated
) up to 91 percent of their chemicals into their offspring, especially the firstborn. It’s a much greater transfer than what occurs during gestation. And because their milk is so much fattier than ours, it also contains a much higher concentration of pollutants such as DDT and PCBs. The levels in firstborn calves sit above the threshold for which serious health effects can be expected, said biologist Randall Wells, a senior conservation scientist with the Chicago Zoological Society. And in fact, firstborn bottlenose calves off the coast of Sarasota, Florida, experience a much higher mortality rate than their younger siblings, about 70 percent versus 40 percent. This could be due to a variety of factors (such as maternal inexperience), but Wells said he wouldn’t be surprised if pollution plays a role. “It does make me concerned for mammals,” he said. “I wish we didn’t have to contend with pollution along with everything else.”

IF WE WANT TO REDUCE OUR TO EXPOSURE TO THESE COM
pounds, we need to know more about where they come from. Wanting to trace how those flame-retardants in my breast milk got there, I decided to start with my house dust. Because the compounds are not molecularly bound to the foam, they easily migrate out of their products and attach to dust, where they can be inhaled or ingested by women like me. So I collected dust from my vacuum cleaner bag and sent it off to Duke University. There toils Heather Stapleton. A dedicated young environmental chemist and new mother, Stapleton has become something of a flame-retardant queen. She recently made a splash by figuring out that house dust, not food, is our major source of exposure to PBDEs. (Of course,
breast-feeding infants are an exception to this rule, since they do get most of their load from milk.)

A couple of months later, Stapleton sent me a spreadsheet. Each “congener” or molecular type of PBDE (there are dozens) leaves a fingerprint, and they can be traced. Once again, my self-image as a granola girl was dinged: I had average-to-high levels of these substances in my home. For example, one congener, deca-209, is found in the hard polystyrene backsides of TVs and monitors. This is the flame-retardant not yet phased out in the United States. Based on a study of homes in Boston, the mean level for this congener in house dust is 4,502 parts per billion. My dust’s deca-209 level was 5,279, probably because we have two home offices. I shouldn’t feel so bad, though; one house had 185,600. What were they doing in there? Was that Mark Zuckerberg’s dorm? On the other hand, the mean level for penta-47 (used in foam furniture) is 1,865. My level was 632. My level of octa-203 (used in electronics) was nearly triple the mean of 3.6. The portrait of my home, in other words, is pretty typically plushed, wired, and, well, dusty.

On the upside, dust studies of homes in the United States and Europe show that PBDE levels are starting to drop modestly, reflective of the bans and phase-outs. Our levels in milk will soon be leveling off and dropping as well. But hold the champagne. Flameretardants are like the story of Hydra. You cut off one head and you get eight more. Since PBDEs have waned, some seventy-six new and suspect flame-retardants have taken up their call. My detective work was not yet complete.