After my daughter was born, I decided, after reading some scientific reports, to get my breast milk tested for industrial chemicals. I’d heard many everyday chemicals used in commerce are attracted to fat, and some of them accumulate in mammalian tissues, where they persist for a long time with largely unknown biological consequences. When I got the results, I learned that my breast milk (my daughter’s exclusive food source) clocked in with above-average levels of brominated flame retardants for U.S. women. This was alarming, but perhaps just as alarming was learning that levels in U.S. women were 10 to 100 times higher than those of anyone else in the world. We have 40-year-old California furniture flammability standards to thank for this. (For an excellent take-down of the bromine industry’s work behind the scenes, see this series in the Chicago Tribune.)
Half a century ago, the United States was a global leader in environmental legislation. After Rachel Carson published Silent Spring in 1962, we banned DDT, a commonly used pesticide that was turning up in human breast milk. From 1957 to 1961, when thalidomide was prescribed to thousands of pregnant women in Europe, causing devastating birth defects, the U.S. kept the drug off the market because one FDA pharmacologist believed more testing was needed. But today, when it comes to such regulatory matters, our lawmakers lag behind the rest of the world—and it’s women, and all of our children, who are paying the price.
At the time I tested my milk eight years ago, little was known about the possible health effects of these substances in humans, but since then, more work has been done. One of the more alarming studies of California women found that for every 10-fold increase in the concentration of four common formulations of flame retardants, there was a 30 percent decrease in the odds of getting pregnant each month. But there is still much to be learned about the effects of these chemicals on women and fetuses. (Breast milk, incidentally, is still preferable to formula from a health standpoint.)
Since I did my test, I’m happy to report that the class of flame retardants in question is being quietly phased out of use. Consequently, its levels in breast milk are falling. The legal flammability standards remain in place, however, and eerily similar substances—also largely untested—have stepped in to fill the commercial void.
We’ve long known that environmental exposures can reduce fertility in both women and men. The reasons are both subtle and overt, and some are still being teased out. We do know that chemically induced DNA damage affects eggs and sperm. In 1954, a boatful of Japanese fishermen exposed to fallout from hydrogen-bomb tests in the South Pacific, for example, returned home with no hair and fast-falling sperm counts. That was an unfortunate real-life experiment. It’s pretty well impossible to design controlled experiments using humans, but Dr. Patricia Hunt, a geneticist at Washington State University, has been dosing animals like mice and rhesus monkeys with bisphenol A, or BPA, the ubiquitous additive used to harden plastics. In both species, she’s found that the chemical damaged the chromosomes of adult eggs, leading to miscarriages and a greater likelihood of birth defects.
BPA was invented in the late 19th century using a byproduct of petroleum as a molecular backbone. By the 1930s, drug makers figured out it was estrogenic, and wondered if they could market it to women to prevent miscarriages. In the 1930s and ’40s, scientists were starting to synthesize artificial hormones, like cortisone, which turned out to be great for arthritis but caused serious side effects. BPA was a weak estrogen, and it was replaced by a compound called DES. Taken by millions of women between the 1940s and ’70s, DES was finally discovered to be causing rare vaginal cancers and malformed uteri in the reproductive-aged daughters of women who took it.
For a long time it was assumed, to the boon of pharmaceutical companies, that chemicals like DES, BPA, DDT, and thalidomide couldn’t cross the placenta. But it became glaringly obvious that they did, and that the fetus, particularly, was vulnerable to carcinogens and mutagens. Now scientists believe the fetus is also sensitive to endocrine disruptors at very low doses. After that, it can become a multi-generation problem.
As BPA researcher Hunt puts it, “The really stunning thing about the effect is we’re dosing grandma, it’s crossing the placenta and hitting her developing fetus, and if that fetus is a female, it’s changing the likelihood that that female is going to ovulate normal eggs,” says Hunt. “It’s a three-for-one hit.”
In addition to containing flame retardants, my breast milk also came back positive for just trace amounts of PCBs, a class of industrial compounds used to insulate machinery. Although PCBs have been banned for nearly 40 years, they persist in the environment for decades. The chemicals we are using—and not testing—today could potentially pose problems for our daughters and their daughters.
In 2004, the United Nations implemented the Stockholm Convention’s Treaty of Persistent Organic Pollutants. One hundred sixty-two countries agreed to ban or severely restrict 21 of the most egregious chemical offenders—those that meet the magic trifecta of concern: toxicity, persistence, and the ability to bioaccumulate in living tissues. Most are pesticides, but several more are flame retardants, dioxin, and PCBs, all the top-billed breast milk additives.
The U.S has not ratified the treaty.
In its lifetime, the Environmental Protection Agency has only banned a handful of chemicals. Under the Obama administration, after 12 years of political stonewalling, the agency finally restricted use of formaldehyde, a known carcinogen. Congress has also held up much-needed reforms to the Toxic Substances Control Act, the weak-kneed legislation governing chemicals testing.
Today, Europe is a safer place than the United States to gestate and nurse a baby. And while we seem to be moving ahead—haltingly, and without the full support of our politicians—we have no way of knowing what the future holds for the coming generations. We can hope, though, that where we once pioneered toxicological testing and regulations, we can do the same for hormone-disrupting substances, and concurrently pressure manufacturers to use safer alternatives. Both steps require vigilance from scientists, the public, and from government leaders. This administration has gone out of its way to support reproductive rights. Let’s hope they recognize that fetal and reproductive health are just as deserving.