Chemistry Lessons: Living With Rachel Carson's Legacy

This story originally appeared in Issue 6 of our new weekly iPad magazine, Huffington, in the iTunes App store.

From Lynne Peeples at The Huffington Post

As you read this, a menagerie of chemical pollutants is coursing through your body. What you do and how you live doesn't matter. You have inhaled them, you've eaten them, you've absorbed them through your skin. You're doing it right now.

If you are an average American, your personal chemical inventory -- embedded in your blood, your breath and your bones -- will include an alphabet soup of phthalates, mercury, perfluorinated compounds, bisphenol A, and assorted chemical flame retardants.

If you are a new mother, you are passing these chemicals to your child through your breast milk. If you are pregnant, you are delivering them through your umbilical cord.

These inescapable realities of modern life -- realities that have vexed environmental advocates and worried scientists for years -- are not new. They were all foreseen, with sometimes chilling accuracy, 50 years ago this summer, when an unassuming marine biologist from Springdale, Penn., named Rachel Carson began publishing a series of articles in The New Yorker Magazine. Carson's essays, which accused the chemical industry of calculated deception and American regulators of wanton disregard for the proliferation of pesticides and other chemical pollutants released into the environment, would ultimately be published as the book "Silent Spring" -- considered by many to be the clarion call of the modern environmental movement.

Today, one study after another repeats the same cautions Carson raised decades ago, including how the tiniest chemical exposures can lead to long-term harm, especially to children.

“We’ve discovered many things that Carson intuitively anticipated, and also some things that she would’ve never imagined,” says John Peterson Myers, CEO and chief scientist at Environmental Health Sciences.

Optimists, Myers included, suggest that, by combining Carson’s prescient insights with modern advancements in biology and chemistry, we can preserve the health of future generations.

In 2010, chronic diseases such as heart disease and cancer surpassed infectious diseases as the leading causes of death across the world, notes Bruce Lanphear, an environmental health expert at Simon Fraser University in British Columbia. “That can be seen as both troubling and an opportunity,” he says, suggesting that we have the potential to eliminate some of the exposures now implicated in chronic diseases. “The problem is that it is really the mega-corporations that are designing, or keeping us from developing, regulatory policies to protect people.”

More than 80,000 chemicals currently used in the U.S. have never been fully tested for their potential to harm humans or the environment, according to the Natural Resources Defense Council.

“Maybe we didn’t heed a warning,” says environmental activist and lawyer Erin Brockovich. “Can we really afford to wait another 50 years?”

To celebrate the 50th anniversary of Silent Spring, Huffington decided to review five of Rachel Carson’s warnings made decades ago to see how they measure up today.

#1: “ Every human being is now subjected to contact with dangerous chemicals, from the moment of conception until death.”

A few years before she was pregnant with her first child, Elsie, Hannah Pingree got tested for toxic chemicals as part of a demonstration study by public health groups.

Although she has lived most of her life on an island 12 miles off the coast of Maine, her blood, hair and urine showed high levels of flame retardants, mercury and phthalates. “I was living nowhere near anything industrial,” says Pingree, former Speaker of the Maine House and now a consultant for “Safer Chemicals, Healthy Families,” a national coalition working to reform toxic chemical regulation. “This was simply from interacting with the environment and in my home.”

Pingree is now pregnant with her second child. As she knows, and as Carson suggested but had no way of proving at the time, exposures to toxic chemicals begin in the womb. Whatever exposures a mother encounters, so too does her future child.

As Carson wrote in The New Yorker on June 30, 1962: toxic chemicals have “entered the environment of almost everyone — even of children as yet unborn.” Within the body of the story, was an ad from the chemical giant Dupont Co. promoting its motto: “Better Things For Better Living … Through Chemistry.”

“Back in mid-century, a lot of people thought that the placenta was a barrier to environmental chemicals,” says Tracey Woodruff, a reproductive health expert at the University of California, San Francisco. It was some 40 years after Silent Spring’s publication when scientists finally confirmed Carson’s hunch — finding nearly 300 different industrial chemicals in samples of umbilical cord blood.

Pingree also knows, as did Carson, that a rapidly developing fetus or child is particularly vulnerable to the effects of those chemical exposures. Childhood cancer may be one tragic consequence. Carson pointed out that “more American school children die of cancer than from any other disease.” A statistic that holds true today.

In many cases, however, the effects of early life exposures don’t appear for decades, and once they do, they’re almost impossible to trace back to their origins, Carson noted. “A child is not going to necessarily wake up with some rash, but they may later have cancer at age 50,” says Pingree. She is less worried about her now 16-month-old’s “daily survival,” and more about the long-term effects of “things like pesticides and the plastic she’s chewing on.”

Still, Myers, the chief scientist at Environmental Health Sciences, points to a “remarkable ray of hope.”

“We’re learning that we actually may be able to prevent chronic diseases of adulthood by reducing exposures in the womb,” he says.

#2: “ Once they were kept in containers marked with skull and crossbones.”

Pingree does everything she can to limit both her and Elsie’s chemical exposures. Like other parents, however, she finds the task frustrating.

“It’s impossible for a parent to live their life trying to make the right decisions about chemicals. There are so many things we don’t know,” says Pingree. “We have this system that allows all of us to have these levels of consumer and industrial chemicals without any idea how they got in there.”

Potentially toxic chemicals are pervasive yet generally invisible — from pajamas treated with flame retardants to bisphenol-A leaching out of plastic bottles to pesticides lingering on fruits.

Parents faced much the same predicament 50 years ago. “Lulled by the soft sell and the hidden persuader,” wrote Carson, “the average citizen is seldom aware of the deadly materials with which he is surrounding himself.”

Manufacturers are rarely required to disclose ingredients in their products, notes Woodruff. And when they do, there are often loopholes such as the requirement that a pesticide label need only include the names of “active” ingredients.

“You can’t know it if you don’t see it,” she says.

Further, disclosures are irrelevant if no tests have been done to identify harmful effects. This is the case for tens of thousands of chemicals common in consumer products. Aside from substances designed to be ingested as food or drug, newly developed commercial chemicals are virtually unregulated in the U.S. — until and unless they are proven harmful.

“The burden of proof in this country is on proving a chemical is dangerous rather than on the side of those who introduce the chemical to prove that it is safe,” says Eric Chivian, director of Harvard Medical School’s Center for Health and the Global Environment. Europe, he notes, has it the other way around.

Carson expressed her own frustration with the U.S. government’s lack of chemical regulation.” If the Bill of Rights contains no guarantee that a citizen shall be secure against lethal poisons distributed either by private individuals or by public officials,” wrote Carson, “it is surely only because our forefathers, despite their considerable wisdom and foresight, could conceive of no such problem.”

Of course, there are also those unintentional ingredients that find their way into products today without anyone’s knowledge. A study published in May suggested that peanut butter can be a source of trace amounts of flame retardants.

“There are always little surprises that we’re finding,” says Woodruff.

#3: “ The chemical war is never won, and all life is caught in its violent crossfire.”

Though women’s nylons were the subject of the 1962 DuPont ad that adorned Carson’s New Yorker article, the company also had a big hand in the pesticide business. In fact, DuPont was a major manufacturer of the prime antagonist in Silent Spring: DDT.

Worry over the widespread aerial spraying of the pesticide inspired Carson to pursue her book.
“Not only forests and cultivated fields are sprayed, but towns and cities as well,” she wrote. “The legend that the herbicides are toxic only to plants and so pose no threat to animal life has been widely disseminated, but unfortunately it is not true.”

While DDT was banned in the U.S. a decade after the publication of her book, and subsequently banned for agricultural use worldwide, Carson’s concerns persist. DDT remains in limited use for the control of mosquito-borne diseases and replacement pesticides now pose their own risks.

Environmental advocates fear widespread poisoning, as well as a continuing arms race with nature that they say humans are destined to lose.

“Evidence of aerial spraying this year in California points to the pesticide treadmill that Carson had acknowledged 50 years ago,” says Paul Towers of the nonprofit Pesticide Action Network.

Mosquito districts in the state are enlisting more toxic chemicals than they had in years past for the control of West Nile Virus due to concerns over pesticide resistance in mosquitoes. Insects that can withstand a spray are more likely to spawn the next generation of pests. And over time, this survival of the fittest can render useless whatever chemical concoction is employed.

Meanwhile, industrial agriculture may soon transition to a genetically-modified corn resistant to two common pesticides, Roundup and 2,4-D, in response to growing resistance among weeds. The result, advocates fear, is the use of stronger doses of the herbicides. Roundup has been shown to disrupt human hormones; 2,4-D was a component of Agent Orange.

Matt Liebman, of Iowa State University, foresees weeds evolving resistance to the new variety of corn within a few years. “Then we’ll be on same treadmill that we’ve been on,” he says.

“Carson was not arguing for banning all pesticides,” notes John Wargo of Yale University, who spent six months going through 117 boxes of Carson’s personal files. “She was simply arguing against the broad-scale prophylactic application that would lead to widespread contamination and exposure. Her arguments follow a train of logic and a narrative that would be extremely useful today.”

#4: “ The contamination of our world is not alone a matter of mass spraying. Indeed, for most of us this is of less importance than the innumerable small-scale exposures to which we are subjected day by day, year after year.”

Earlier this year, the U.S. Centers for Disease Control and Prevention declared that there is no safe level of lead in the bloodstreams of children. Even in tiny amounts, exposures to the heavy metal via dust and flakes of lead paint can damage a child’s developing brain.

Scientists today are also heard stating similarly grim warnings about a growing number of environmental toxins, found in a lengthening list of places.

“People took Carson somewhat seriously in the case of DDT, but she was also talking in very broad terms about chemicals,” says Pingree. Whether from eating a piece of salmon or breathing in second-hand smoke or chemicals sprayed on a lawn, each of our everyday exposures may be tiny, though not necessarily insignificant.

“One part in a million sounds like a very small amount — and so it is,” wrote Carson, referencing a likely amount of pesticide residue on food. “But such substances are so potent that a minute quantity can bring about vast changes in the body.”

Lanphear of Simon Frasier University notes that we are now worrying about even smaller exposures than Carson was suggesting. “Parts per billion,” he says.

Recent research has also questioned the popular notion that “the dose makes the poison.” Minuscule concentrations of chemicals that disrupt hormones — common in industrial pollution, pesticides and plastics — may have potent effects, sometimes even when large doses of the same chemical appear harmless. Some chemicals also can accumulate in the environment and the human body, where they can combine and interact with other chemicals.

“This is why there is no ‘safe’ dose of a carcinogen,” Carson wrote. Carson pointed out one combination of chemicals that had already raised red flags among scientists: malathion mixed with other organophosphate pesticides. Administered together, she wrote, “a massive poisoning results — up to 50 times as severe as would be predicted on the basis of adding together the toxicities of the two.”

Organophosphates, including malathion, are still in use today.

“Things are far more complicated chemically than they were in Carson’s time,” says Wargo. “There are so many uses of many more active ingredients, inert ingredients and differently formulated products that it’s become difficult for governments to identify the risks.”

“We are now living in a world probably beyond what Carson could have ever imagined, in terms of the number of chemicals kids interact with every day,” says Pingree. “And we’re having all the impacts that she worried about.”

#5: “ These injuries to the genetic material are of a kind that may lead to disease in the individual exposed or they may make their effects felt in future generations.”

In other words, if you happen to be obese or infertile, facing cancer or diabetes or any number of other diseases, it might well have something to do with your father’s exposure to a plastic toy in 1955, or even his father’s exposure to his comrades’ chemical-laced second-hand smoke after he successfully stormed the beach at Normandy. Your own children and grandchildren may even pay the price of the ancestral exposures.

Carson hinted at this possible new spin on nature versus nurture 50 years ago, and scientists are only now confirming her suspicions.

“That was a very insightful comment for the time,” says Michael Skinner, a leading expert in an emerging field called epigenetics at Washington State University. “It came long before we had any data, before anything was appreciated about this.”

Studies published over the last couple of months have bolstered the notion that toxic chemicals in our ancestors’ environment could help explain cases of a variety of diseases and cognitive problems that we and our children suffer today — even without exposure to the contaminants ourselves.

“Many behavioral diseases like autism run in families but do not follow normal genetic patterns,” says Skinner. “Our findings really fit the bill.”

Environmental insults don’t necessarily have to alter our genetic code to cause lasting trouble, Skinner and other scientists have discovered. They also can disrupt the body’s ability to interpret these inherited instructions, and in certain cases, this so-called epigenetic defect is handed down and becomes more pronounced in subsequent generations.

A young soldier exposed to Agent Orange in Vietnam, for example, or a kid caught in a drift of DDT insect repellant on his 1950s cul-de-sac, might well pass on health consequences to their children, and then to their children’s children, and so on down the family line.

Myers says that he used to “draw solace” from the belief that environmental contaminants such as plasticizers and flame retardants, now likely linked to conditions such as diabetes and asthma, were not affecting any inheritable information. In other words, if you were to remove the exposure, most people thought that the next generation would be spared.

“This casts a significant shadow of a doubt,” he said, “on that assumption.”