Chemicals Good for Your Lawn Could Be Bad for You

I’ll do anything to avoid yard work. And it shows. On a street lined with brilliant green lawns and colorful flower beds, our little patch of heaven often looks like hell. Faced with the choice of playing golf or trimming grass and tending to the shrubs, I’ll wield a pitching wedge instead of a weed whacker any day.

It’s not that I’m lazy. OK, maybe I’m a little lazy. But there are certain aspects of yard work that I put off because they give me the creeps. I’m thinking of all the bug- and weed-killing chemicals I would need to dump on my lawn to keep it looking as spiffy as my neighbors’ grass and gardens. If insecticides and herbicides can wipe out armies of bugs and vaporize the gnarliest of weeds, aren’t they capable of messing up my brain and DNA?

A few recent news stories hint that the quest for a perfect lawn could indeed come at a price. In early June, the Environmental Protection Agency banned household use of chlorpyrifos, a chemical found in more than 800 brands of pesticides, including some popular lawn treatments. The agency declared that exposure to chlorpyrifos may cause brain damage, especially in children.

A few weeks later, the Journal of the American Medical Assn. reported on preliminary research at Stanford University suggesting that gardeners who frequently handle or apply pesticides may increase their risk for Parkinson’s disease.

Of course, concerns that pesticides cause cancer and other diseases, as well as threaten the environment, aren’t new. Scientists have been studying these matters since before Rachel Carson wrote her cautionary book, “Silent Spring,” in 1962. But researchers still don’t agree on the actual level of risk facing people who use these chemicals, especially the casual gardener who’s just trying to keep his lawn green and dandelion-free.

“There is not a safe level of exposure to these chemicals,” asserts Columbia University biologist Joe Thornton, author of “Pandora’s Poison” (MIT Press, 2000), a book about the dangers of a specific category of industrial chemicals. These chemicals, called organo-chlorines, are involved in the production of paper, plastics and some pesticides, including 2,4-D, a chemical found in many common weed killers.

“There’s little doubt that 2,4-D causes cancer,” says Thornton, in a phone interview. He cites lab studies of rats exposed to the chemical, as well as surveys of farmers who use 2,4-D and similar pesticides that reveal unusually high rates of Hodgkin’s disease and non-Hodgkin’s lymphoma, as well as prostate and testicular cancers. Not to mention diminished sperm counts.

Thornton also points to a National Cancer Institute study in 1991 that found that dogs are more likely to develop non-Hodgkin’s lymphoma if their owners use herbicides containing 2,4-D.

Think you can learn to live with a few dandelions after all? That’s Thornton’s advice. (Then again, he lives in Brooklyn, where there’s not a whole lot of social pressure to produce a perfect lawn.) Thornton also suggests planting weed-resistant varieties of grass. Of course, using organic gardening techniques may help avoid some of the problems with nasty pesticides. When all else fails, weeds can still be eliminated the old-fashioned way: by yanking them out by the root.

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Other scientists, such as UC Riverside toxicologist Robert Krieger, believe that fears about the dangers of lawn chemicals are overblown. After all, he points out, studies of disease rates among populations such as gardeners and farmers don’t prove cause and effect. In other words, something besides pesticide exposure may have caused the high rates of Parkinson’s disease and cancer.

What’s more, Krieger says, some studies have shown that rats fed 2,4-D don’t get sick--even if they eat the stuff for 113 days in a row. And his own research has determined that when a person applies a lawn chemical, the actual exposure he or she receives is “vanishingly small,” says Krieger. He estimates that a proper application of pesticide exposes a gardener to less than 0.1% of the amount of toxic material it would take to make you sick.

Who’s right? Difficult to say, but if you’re a believer in better lawns through chemistry, you should at least follow some common-sense guidelines when you go hunting for weeds and bugs.

Follow the label instructions on a bag or bottle of pesticide to the letter. Wear a long-sleeved shirt and pants. Wash your exposed skin thoroughly when you’re finished. Keep off the grass or out of the garden until the pesticide has dried or until the instructions say it’s safe. One other thing: Don’t apply weed killer on a windy day. You may end up destroying plants you hadn’t intended to kill and your neighbor’s rose bushes, which could prove hazardous to your health.