CHICAGO — FARM chemicals are suspected by some people - including some farmers - as a potential public health hazard. The evidence of such a threat is debatable, but the perception that one exists poses a public relations problem for agriculture.
``Farmers aren't throwing pesticides around helter-skelter,'' says Don Kuhlman, leader for environmental issues in the college of agriculture at the University of Illinois at Champagne (UIC). He notes that they use far less than even a decade ago, and often apply it at less than the label rate.
Yet, he says, it's farmers' responsibility to demonstrate that their practices over the long term won't endanger the nation's food and water supply or the workings of the environment. ``It will have to be the goal of every farmer to become a better environmental manager,'' Professor Kuhlman says.
Farm chemicals are divided between fertilizers and pesticides used against weeds, bugs, fungi, and rodents. Both types can enter the water supply through evaporation and runoff. Pesticide residues have been found on some food items. The difficulty comes in evaluating the risks from that.
For instance, 60 percent of food has no detectable chemical residue, Kuhlman says. Less than 1 percent has a residue exceeding the tolerance set by the Environmental Protection Agency (EPA), which builds in a safety factor of 100, he adds.
Current testing of synthetic chemicals exaggerates the human cancer risk, notes Luther Tweeten of Ohio State University. These tests are conducted using repeated near-lethal doses. Half of all chemicals, natural or synthetic, are carcinogenic in rodents when tested that way. At the same time, Dr. Tweeten notes, all plants produce natural toxins - many carcinogenic - to protect themselves from insects and fungi.
People consume 15,000 times more natural toxins than pesticide residues each day. Three cups of coffee contain natural carcinogens equal to a year's worth from pesticide residues. A peanut butter sandwich has 18 times greater chance of causing cancer than a glass of apple juice that contained a trace of the chemical Alar, Tweeten says. In short, if carcinogenic content were illegal, almost all food would be banned, he says.
``The consumer risks [from farm chemicals] are probably exaggerated,'' says Chuck Voight, an agriculture professor at UIC. But he adds: ``The user risks are probably underestimated.''
``Users'' means farmers.
Kris Ann Moyer of the National Farmers Union in Denver says the organization's members are increasingly concerned about health problems and are asking: ``Hey, is it because I've been spraying that stuff on my crops all these years?''
``I have some real reservations on chemicals,'' says Joe Sullivan, who has farmed 2,000 acres in Meeker, Colo., for 30 years. A friend of his in the crop-spraying business died of cancer. Mr. Sullivan blames it on the chemicals.
As for the US water supply, Tweeten cites a five-year EPA study of 1,347 wells in 50 states. Completed last year, it found 10 percent of urban wells and 4 percent of rural wells contained at least one pesticide. None of the urban wells and 0.6 percent of the rural wells had residues above EPA standards. The EPA concluded there is no ``immediate widespread health problem.''