Tomato, Potato Sprays Linked to Parkinson’s Disease

The chemicals sprayed on tomatoes and potatoes could be making people who live near farms sick.

March 30, 2012

A common combination of chemicals used to protect the vegetable rows of someone who's planting potatoes, dry bean, and tomato crops from bugs, weeds, and other pests seems to have a very unappetizing side effect. New research out of UCLA backs previous theories suggesting that exposure to pesticides could trigger Parkinson’s disease, a degenerative disorder of the central nervous system that can impair motor skill, speech, and other functions. The new study appeared in this month’s American Journal of Epidemiology. “We were able to show in humans what animal data had previously suggested,” says lead study author Sadie Costello, former doctoral student at UCLA who is now at the University of California, Berkeley. “Animal experiments are done in highly controlled environments in which exposure can be measured . . . the chance of actually seeing an effect in humans is not very high unless there is, in fact, quite a large effect.”

THE DETAILS: High rates of Parkinson’s disease have been reported in farmers and rural populations, raising suspicion that pesticides can trigger the disorder. In this study, researchers enrolled 368 longtime residents of California’s Central Valley who had been diagnosed with Parkinson’s and another 341 residents as a control group. Residents who lived within 500 meters of fields sprayed with the fungicide maneb and the herbicide paraquat between 1974 and 1999 had a 75 percent higher risk of developing Parkinson’s, compared with those who lived farther away. In people diagnosed with the disease before they were 60 years old, researchers found earlier exposure increased their risk for the disease as much as four- to sixfold. Exposure to just one type of pesticide increased their risk more than twofold.


“The results confirmed two previous observations from animal studies,” says Beate Ritz, the study’s senior author and professor of epidemiology at the UCLA School of Public Health. “One, that exposure to multiple chemicals may increase the effect of each chemical. That’s important, since humans are often exposed to more than one pesticide in the environment. And second, that the timing of exposure is also important.”

WHAT IT MEANS: Don’t live near a farm? Don’t think this doesn’t affect you. Centers for Disease Control studies have found that some pesticide chemicals are present in the blood or urine of nearly every person in America. When these chemicals are sprayed on fields, they wind up in our air, soil, drinking water, and food supply. And it’s not always clear which chemicals are most threatening. “We really don't know what the ‘worst’ [pesticides] are because the criteria for evaluating them have been so weak, and the government has largely looked the other way until very recently,” explains Warren Porter, PhD, professor and former chair of zoology, and professor of environmental toxicology at the University of Wisconsin-Madison.

Take the following steps to rid your own property of toxic chemicals to help contribute to the cleanup of our food and water supply:

• Start in your own backyard. Americans dump nearly 90 million pounds of herbicides and pesticides on their lawns every year. If you need a little data to deter you from using chemicals on your lawn and garden, consider the following facts:

‣ Much of those chemicals run off and contaminates drinking water supplies.

‣ A popular chemical in “weed and feed” products, 2,4-D, has been linked to non-Hodgkin’s lymphoma. This chemical was detected inside 63 percent of homes, because it’s tracked in from outdoors.

‣ A Journal of the National Cancer Institute study found exposure to garden pesticides can increase the risk of childhood leukemia nearly sevenfold.


‣ More than half of the 30 most commonly used lawn pesticides are hazardous to birds and toxic to fish and aquatic life. Eleven of these pesticides can impact bees.

‣ Low levels of pesticides can promote miscarriages, and researchers have linked household pesticides to breast cancer in women.

‣ Herbicides used on chemically treated lawns can double your dog’s risk of developing canine lymphoma.

An important point to realize is that you do have a choice: You can have a lush lawn and still protect your family’s health by going organic. Everything you ever needed to know about gardening organically can be found at

• Vote with your wallet. The biggest change you can bring to the American market starts with how you spend your dollar. “Ordinary people can have an immense impact by changing their buying patterns. Buy organic, buy a good water filter, ask restaurants to offer organic items on the menu, get your hospital to go green, and patronize golf courses that have organic practices,” suggests Porter. “Economics is immensely powerful and a change of only 0.5 percent market share has profound effects on a corporation.”