What Is the Real Scientific Consensus on Pesticides?

Published December 1, 2007

According to the Web site of the Environmental Working Group, “There is growing consensus in the scientific community that small doses of pesticides and other chemicals can adversely affect people, especially during vulnerable periods of fetal development and childhood when exposures can have long lasting effects.”

An online petition to ban the use of pesticides in the Canadian provinces of Newfoundland and Labrador claims, “Current scientific consensus is that common lawn chemicals create significant human health risks and pose a threat to our eco-systems.” It cites “the Ontario College of Family Physicians, Newfoundland and Labrador Medical Association, Canadian Cancer Society, Canadian Lung Association, etc.” (http://www.petitiononline.com/NLBan/petition.html)

Canada has imposed sweeping restrictions on the use of pesticides and herbicides, and a growing number of cities in the United States are attempting to ban or restrict their use in parks, schools, and other public spaces.

Is there really a “consensus” on the threat posed by pesticides? If there is, what does it say?

What Doctors, Scientists Believe

What scientists and health experts actually know about pesticides is quite different from what is suggested by the Environmental Working Group and other anti-pesticide advocacy groups. Most would endorse the following summary of what is known:

  • We know synthetic chemicals that might cause cancer in high doses are present in the human diet in extremely small amounts, too small to pose more than a minuscule threat to human health.
  • As our ability improves to detect ever-smaller amounts of chemicals in human and other animal tissue, we are discovering synthetic chemicals are ubiquitous. But just because they are detectible doesn’t mean their presence is harmful. It is still true that “the dose makes the poison.”
  • According to Dr. Bruce Ames, a prominent biochemist at the University of California-Berkeley, we consume 10,000 times more naturally occurring potential carcinogens than manmade pesticide residues, by weight, yet even natural carcinogens are not likely to pose a significant health threat.
  • Age-adjusted cancer rates in the U.S. have been falling, according to the National Cancer Institute, since at least the early 1990s, even while the generation that was most likely to have been exposed to pesticides has reached retirement age.
  • We have discovered connections between genetics, obesity, and infection that explain a growing share of cancer cases that once were mistakenly attributed to exposure to chemicals.
  • Dr. Elizabeth Whelan, president of the American Council on Science and Health, has repeatedly shown how animal testing, while a valuable tool for determining the safety of many kinds of chemicals and drugs, tends to overestimate the likelihood of harmful effects when extrapolated to humans. Human subjects often would have to ingest thousands of gallons or pounds of a suspect substance to achieve the equivalent “dose” received by a laboratory mouse or rat.
  • The benefits of pesticide use are enormous. In crop protection, they increase yields and lower prices, making fruits and vegetables affordable to millions of people. By controlling vermin, they protect the health of children and adults. By battling weeds and termites, they prevent the loss of billions of dollars of property every year.

Junk Scientists

The general public is fed a steady stream of alarmist propaganda that tells a very different story about pesticides. The huge growth in the organic food industry in the U.S. and around the world is entirely the result of public fear of the health effects of pesticides and other synthetic chemicals in our diets.

Most of the false alarms come from one or more of five interest groups that have learned how to profit from anti-pesticide alarmism. They are:

  • the news media, which finds it can sell more newspapers or attract more viewers by exaggerating the tiny and hypothetical risks associated with pesticide use;
  • politicians, who campaign for reelection by promising to protect our children by passing new laws and regulations on chemical manufacturers, even though they surely must know that existing regulations are more than adequate to protect the public;
  • liberal advocacy groups, such as the Environmental Working Group, Pesticide Action Network, and World Wildlife Fund, which raise hundreds of millions of dollars a year by cranking out news releases, newsletters, and fundraising appeals claiming exposure to pesticides is making children sick and immediate action is necessary;
  • government agencies, including the World Health Organization, Food and Drug Administration, and state and local government agencies, which seek to expand their budgets and authority by publicizing dubious research and ignoring contradictory evidence appearing in peer-reviewed journals; and
  • the organic food industry, which pours millions of dollars into liberal advocacy groups and advertising campaigns designed to frighten people about the safety of the food they eat and the water they drink, to boost demand for their own, more expensive and often less healthy, products.

While there are many honest and sincere people working for companies and organizations in these five groups, it is difficult to believe they are all unaware of the true scientific consensus on the safety of food and water in the United States. Some willfully ignore the truth, while others simply lie.

Next month: What we can do to stop the junk scientists!

Joseph Bast ([email protected]) is president of The Heartland Institute and publisher of Environment & Climate News.