Environmental Movement at 40: Is Earth Healthier?

Hillary Mayell
for National Geographic News
April 19, 2002
Forty years ago target="_new">Rachel Carson, a writer and marine biologist,
published Silent Spring, a book documenting the chemical warfare
that human beings were waging on the natural world. The book is widely
credited with launching today's environmental movement.

"silent spring" was her metaphor for the destruction humans were
wreaking on their environment.

As she saw it, a small American town, the farms prosperous, the people healthy and happy, the forests teeming with wildlife—all was silenced, or sickened by a mysterious illness brought on by the people themselves. The "strange blight" was caused by the unexamined and virtually unregulated practice of dumping, spraying, dusting, and otherwise distributing harmful chemicals into the environment.

The chemical industry, government scientists, and the media attacked Carson as a hysterical woman; her facts were called inaccurate, her competency questioned. But her book became a best-seller.

Reviewing the book in 1962, Time magazine joined the crowd, questioning the book's accuracy and the validity of her conclusions; several decades later, the magazine named her one of the 100 most influential people of the 20th century.

Are we better off since Carson opened the eyes of Americans to the destruction being wreaked on nature?

"I think we are better off in the sense that this is known to be a problem and there is some regulation and even prohibition in some cases," said Thomas E. Lovejoy, chief biodiversity adviser for the World Bank and chair of the Conservation Trust Advisory Board of the National Geographic Society.

"Better off than we would have been," he added. "But we continue to introduce new chemicals to the environment, even new categories of threats, and pre-test them insufficiently. And almost nothing is being done to look at combined and possibly synergistic effects."

Monday, April 22, is Earth Day 2002, and the planet's problems are legion. Research and political maneuvering in recent decades suggest that now, more than ever, revisiting Rachel Carson may be imperative.

Persistent Toxins

Carson was the first to introduce the general public to the concept of persistent bioaccumulative toxins—substances that are long lasting, move readily from land to air and water, and can build up in the food chain to levels that are harmful to humans, wildlife, and the environment. These compounds can be found everywhere—in herbicides, pesticides, insecticides, detergents, plastics, and even cosmetics.

When Carson wrote her book, toxicity testing of new chemical compounds was limited to figuring out whether exposure to a chemical at high concentrations would cause cancer. Since then, scientists have discovered a previously unsuspected threat posed by many synthetic chemicals: the ability to disrupt the body's internal chemical messaging systems.

Even at very low levels of exposure, these so-called endocrine-disrupting chemicals can alter sexual, neurological, and behavioral development, impair reproduction, and undermine immune systems. It's not merely a question of dying young; research suggests that some of these chemicals could leave generations of people with subtly impaired intellectual functioning, reduced fertility, and weakened immune systems.

"No one would have believed ten years ago what we're finding out today," said John Peterson Myers, a zoologist and co-author of Our Stolen Future. "Low doses matter. We're now aware that it doesn't take a lot to cause a big effect. The atrazine story is a case in point."

A research study published in the April 16 issue of Proceedings of the National Academy of Sciences found that exposure to as little as 0.1 parts per billion of atrazine, the most common weed killer in America, caused reproductive abnormalities in frogs.

Atrazine can be found everywhere—in rainwater, snow runoff, and groundwater. There is virtually no atrazine-free environment, according to Tyrone B. Hayes of the University of California, who led the research.

Regulating Pollutants

"We're in the midst of a revolution that started with Rachel Carson, and what we're learning today will require fundamental changes in how we structure regulating these chemicals," said Myers. "Faced with this kind of data, we can't keep looking at just one chemical at a time. We experience soups of chemicals that all interact with one another. There has to be a new standard—the system we have now is broken."

Change will not come easily or swiftly.

On April 12, the Bush administration announced that it was submitting the Stockholm Convention on Persistent Organic Pollutants (POPs) to Congress—with some modifications. The international treaty, approved by 127 nations in May 2001, calls for the complete elimination of the "Dirty Dozen": 12 chemicals that persist in the environment and are acknowledged to be extremely harmful to humans.

Although the United States signed the treaty, the enabling legislation sent to Congress eliminates a provision in the treaty that allows for the addition of new chemicals to the list if scientific evidence warrants it. Atrazine, the weed killer that causes frogs to develop male and female sex organs at concentrations 30 times lower than what is approved by the Environmental Protection Agency, is not one of the 12 POPs named in the treaty.

The burden of proof in regulating chemicals needs to be changed from one in which harm must be demonstrated before a product is withdrawn, to an approach where safety is ensured beyond reasonable doubt before widespread deployment is allowed, Myers argues.

"Europe is far ahead of the United States in adopting a precautionary approach on this issue," said Myers. "The Swedish Chemicals Policy Committee has developed a standard that says if it's persistent and bioaccumulative, you don't need to show toxicity—that's enough. And that's the direction we need to be heading in."

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