Downstream From 'Silent Spring'

By Robert L. Wolke
Wednesday, June 6, 2007


Local beekeepers sold organic honey, bakers displayed artisanal loaves, and some of Pittsburgh's best chefs offered dishes made with products from nearby organic farms, including the renowned lamb from Jamison Farm, an hour away. Under small tents, representatives of the Audubon Society, the Sierra Club, the Carnegie Museum of Natural History, Slow Food Pittsburgh and Whole Foods Market handed out materials about environmental conservation.

It was a birthday party: the 100th anniversary of the birth of Rachel Carson, held at her birthplace, a 30-minute drive from my home in Pittsburgh. How could I not go?

Carson's 1962 book, "Silent Spring," changed the world. By exposing the devastation being wrought upon nature's flying and walking creatures by the undisciplined spreading of powerful chemicals to kill the crawling ones, she awakened the world to the harmful environmental consequences of human activity. Among her legacies are the Environmental Protection Agency and the Clean Air, Clean Water and Endangered Species acts.

But how far have we come since "Silent Spring"? Walking around the event, I asked a dozen or so people whether they think we are better or worse off today regarding the hazards of pesticides. Among those who, like me, were around in the 1950s, the predominant view was a split decision: America is better off because scores of highly toxic pesticides have been banned (remember DDT, chlordane, dieldrin?), but the Third World is worse off because those same chemicals are still in use there. Most poor, food-strapped countries have tropical or semitropical climates in which insects flourish, and pesticides may offer the only hope of an adequate harvest.

My younger interviewees, though, tended to think we are worse off today than in Carson's time. Why? Because, they say, today's factory farms are using not only pesticides but also herbicides, chemical fertilizers and animal hormones with little restraint, compromising the wholesomeness and safety of our foods as never before.

Let's examine that train of thought.

It is hard for today's environmentally conscious generation to realize how naive and primitive we were in the 1940s and 1950s. I can remember being shooed indoors by my mother when the fogging trucks came by, spraying mosquito-control DDT on the New York City beaches. I can remember movie newsreels (tell the kids what newsreels were) showing crop-dusting airplanes spraying 2,4-D over acres of farm fields; that chemical, when combined with 2,4,4-T, is the notorious Vietnam War-era Agent Orange. And I can remember (mea culpa) using black-market chlordane to fight the cockroaches when I lived in Florida. Are things really worse now?

The EPA, created eight years after "Silent Spring," sets "tolerance limits" for pesticide residues in food and water, based on each chemical's degree of risk to human health. All amounts are measured in parts per million (ppm). To illustrate, one ppm would be equivalent to one inch of a 16-mile-long carrot.

The U.S. Department of Agriculture enforces the EPA tolerance limits for meat, poultry and some egg products, while the Food and Drug Administration enforces the limits for all other foods. From 1991 to 2006, the USDA tested 118 types of food products for the presence of more than 440 different pesticides. Regardless of what one might think about the effectiveness of our politicized and lobby-driven federal agencies, that's an awful lot of watching over our foods.

According to the FDA, more than half of the samples of produce tested do not even show measurable toxic residues. Fewer than 1 percent of tested samples exceed the tolerance limit of a given pesticide plus the chemicals it breaks down into in the environment. Moral: The fact that a pesticide was used in growing your fruit does not mean pesticide residue will still be there when you buy it. But wash it anyway.

We still have a long way to go, and slip-ups can occur, in part because of the inadequate number of inspections of our gigantic cornucopia of American and imported foods, a shortage the agencies will be quick to ascribe to inadequate leadership and funding.

But better off than in 1962? You bet your bananas.

Robert L. Wolke ( is professor emeritus of chemistry at the University of Pittsburgh and author of "What Einstein Told His Cook: Kitchen Science Explained" (W.W. Norton, 2002). He can be reached

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