Sugar and Spice and…Lead and Mercury

Of all members of a human population, fetuses are the most vulnerable to toxic harm.
This post is 6 in the series: Sustainababy: Born to be Green

Sandra Steingraber is my hero. Her book, Having Faith: An Ecologist’s Journey to Motherhood, chronicles her own pregnancy from both a scientific and personal perspective. It’s beautifully and lovingly written—yet for a pregnant woman it’s also a tough read. Trained as a biologist, Steingraber meticulously documents the toxic hazards we live with every day, and that threaten each crucial stage of fetal development.

It’s not a pretty picture.

Food ChainOne point stands out: it’s the fetus, not an adult human, who really lives at the top of the food chain. Rethink all the textbook food chain charts you’ve seen in your life, where the silhouette of a grown man stands at the top, above all the flora and fauna. It should be a pregnant woman standing there, with a big arrow pointing at her belly. And “biomagnification” means that the higher up an animal is on the food chain, the greater its exposure to toxic chemicals. Sometimes, those concentrations rise by a factor of 10, or even 100, with each successive step up the food chain. The fetus, at the pinnacle of that chain, absorbs a higher concentration of food-borne and water-borne chemicals than its mother—at the very stage of life when it is most susceptible to toxic insult. In Steingraber’s words, “of all members of a human population, fetuses are most vulnerable to toxic harm.”

The potential consequences are serious. Toxic chemicals and pollutants have been linked with a range of birth defects and developmental delays, from the subtle to the acute: hyperactivity, learning disorders, impaired intellectual capacity, behavioral disorders, immune system impairments, compromised reproductive capacity, heart defects, circulatory problems, mental retardation, cancer, and deformed faces, limbs, and genitals, just to name a few of the nightmarish things that keep pregnant women up at night.

The thing is, some of these toxics are virtually ubiquitous in the environment—there’s no way to avoid all of them, no matter how careful you are. So, for all of the choices I’ve made to ensure the healthiest possible outcome for my pregnancy, there are just as many decisions about toxic chemicals that were already made for me.

So…is the fetus growing in my belly made of sugar and spice…or lead and mercury?

Coal-fired power plants are the largest source of mercury in the US. The mercury released from smokestacks here and abroad rains down into waterways, where natural processes convert it into methylmercury—a form that allows the toxin to wend its way up the food chain into fish.

John E. Amos Coal Power PlantI wonder what would happen if we reminded more mothers and fathers (and grandmothers, aunts, teachers, policymakers) that mercury—a toxic, persistent pollutant that accumulates in the food chain—can create serious risks for children, including “poor performance on neurobehavioral tasks, such as those measuring attention, fine motor function, language skills, visual-spatial abilities and verbal memory.” Would they pay more attention to climate legislation that would shift our dependence on dirty fossil fuels to cleaner, safer technologies?

Or is the alternative really just to keep pumping more resources into special-needs programs in our schools? Really??

According to a February 2009 report by Environmental News Service, “some 1,100 coal-fired units at more than 450 existing power plants emit 48 tons of mercury into the air each year.” Yet only 1/70th of a teaspoon of mercury is needed to contaminate a 25-acre lake to the point where fish are unsafe to eat. All but two US states have instituted fish consumption advisories, with over half of those mercury advisories applying to all water bodies in the state. A study released in August found that every fish in nearly 300 streams across the country was contaminated—one quarter of them at levels higher than EPA standards for human consumption. In November, the EPA released a study that found the neurotoxin mercury in game fish in 49 percent of lakes and reservoirs nationwide. (The study also found polychlorinated biphenyls, or PCBs—a mostly banned industrial chemical and probable carcinogen—in game fish at levels of potential concern in 17 percent of lakes and reservoirs sampled across the nation.) The Centers for Disease Control has found that as many as six percent of American women have mercury in their blood at levels that would put a fetus at risk of neurological damage.

Yikes.

Until quite recently, doctors and scientists thought that the womb worked as a magic barrier that kept everything bad away from a fetus. Not so. In fact, as Steingraber points out, the placenta invites some substances of a certain weight or profile—lead, for example—to come right in. Lead, it turns out, is a traveling companion to calcium. The placenta wants to deliver much-needed calcium to the developing body, and brain-damaging lead comes along for the ride. Lead has been shown to cause lower IQ scores in children. It is linked to mental retardation, anemia, hearing loss, and nerve damage, as well as aggression, poor language skills, short attention spans, hyperactivity, and delinquency. “We now know that lead can decrease mental acuity at levels one sixth those required to trigger physical symptoms,” Steingraber writes, “There is no safe threshold for lead exposure in fetuses.”

But lead—for all its lingering residue in our houses, our gardens, our air and water, and for all its lasting neurological effects—is actually a policy success story.

Lead has been in use since Roman times (even then, it was linked with mental illness, disease, and death), but over the last several decades, public health campaigns and new regulations have focused on reducing exposures. The success of these reduction efforts can be measured by declining blood level concentrations in humans. But it was an uphill battle to institute the strong community standards that resulted in these successes. Here’s a lead policy timeline—showing a progression from grave error to common sense:   

  • 1923: Leaded gasoline went on sale for the first time in the United States.

  • 1925:  After a rash of deaths in the plants that produced the gasoline additive, the US Surgeon General temporarily suspended the production and sale of leaded gasoline—but soon after, the lead industry released its own quick study that indicated no problems with lead exposure and the ban was lifted. No compulsory standards were set for 5 decades.
  • 1925, an international covenant banned lead-based paints for interior use in much of the world, acknowledging that lead was a neurotoxin. Faced again with industry pressure (namely from Lead Industry Associates), the United States was n
    ot a signatory to the agreement (around the same time, the lead industry also successfully lobbied against restrictions on lead in US plumbing and fought labeling requirements that would warn buyers not to use lead paint on children’s toys, furniture, or rooms.).

  • 1973:  The US Environmental Protection Agency initiated a phase-out of leaded gasoline.
  • 1977:  Lead paint banned in the US.
  • 1990:  Lead in gasoline was banned completely—after 70 years of use, with 15.4 billion pounds of lead released into the atmosphere, much of which has sifted down into the topsoil.

Because of lax community standards in place in the United States through much of the 20th century, most homes built before 1978 contain lead paint—and children and pregnant women living in those homes continue to face risks from it. A Right-to-Know law to warn of these risks in real estate transactions and rental agreements was implemented by the EPA in 1996.  But since lead was phased out, levels in the human body have plummeted. According to the US Center for Disease Control and Prevention, average concentrations of lead in the US population’s blood have decline by a whopping 75 percent between 1976 and 1991, and fell even further by 2002.

Steps are still being taken to eradicate lead for good. In 2008, after a scare about lead-contaminated toys imported from China, Washington’s Gov. Christine Gregoire signed the Children’s Safe Products Act boasting the toughest lead standards in the nation, a limit of 90 parts per million (ppm). Then the US Congress passed its own law with lead standards, the Consumer Product Safety Modernization Act, signed by President Bush in August.

Meanwhile, it’s been an even steeper uphill battle to rein in mercury pollution—a decades-long battle in which community standards have made little headway. In 2009, after a federal appeals court threw out plans drafted by the Bush administration and favored by industry, the Obama administration said it would begin crafting new regulations to control mercury emissions from power plants. The Bush rule would have allowed power plants to buy and sell pollution credits, instead of requiring each plant to install equipment to reduce mercury pollution. The EPA has also proposed a new regulation to clamp down on emissions of mercury from cement plants. These are baby steps—and they come far later than common sense would dictate (that is, if human health came before industry profit in legislative decision-making.)

I’ll write about this more later, but fish (the food that’s most likely to contain unhealthy levels of mercury for pregnant women) is also one of the best sources of omega-3 fats (DHA and EPA), some of the best stuff in the world for brain development.

On the surface, our culture appears obsessed with preventing and detecting birth defects. Pregnancy books are rife with cautions against alcohol and cigarettes during pregnancy. A pregnant women with a glass of wine in her hand can get furious stares in polite company. Yet society’s obsession with fetal health has limits: it focuses almost exclusively on the personal choices of a pregnant woman.  The choices we make together as a community—the standards we choose for our water and air and food, and how our electricity is produced—can be just as important to fetal health as personal decisions, yet all too often are simply overlooked—or outright trumped by pressure for profit.

But if we insist that a pregnant woman make responsible choices for her baby—and declare anything less reckless and irresponsible—shouldn’t we demand the same high standards for the community at large?

Photo courtesy of Flickr user Wigwam Jones under a Creative Commons license.

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Comments

  1. Eric de Place says:

    First-rate post, Anna!One of the things from Steingraber’s book that was most arresting to me was her history of lead paint policy in the US. It’s eerily similar to the environmental debates we have today: industry did everything it could to obfuscate evidence, confuse the public, and lean on elected officials. (In fact, the little boy that appears on Dutch Boy paint cans originated as a tactic to convince parents that it was safe to use leaded paint in their children’s rooms and on their furniture!) Unfortunately, as with climate policy to date, industry was largely successful in their campaign to preserve the status quo, children be dammed.

  2. got mercury says:

    To estimate your mercury exposure from fish check out the free online mercury calculator at http://www.gotmercury.org. Based on the current U.S. EPA and FDA guidelines, the mercury calculator is an excellent way to know your potential mercury exposure risk. You can also use the free mobile mercury calculator for cell phone browsers at http://www.gotmercury.mobi

  3. Working Dad says:

    What a thought-provoking blog post. So much time is devoted to alleged harm from vaccines, when coal plants are real threats to pregnant women. Thanks, looks like I need to get a copy of the book.

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