Pesticides and Perception of Risk
Are natural products safer than synthetic ones? This is a fundamental question that has been asked by faculty who have reviewed the scientific literature such as Dr. Joel Coats of Department of Entomology at Iowa State University. It is a difficult question to pose and analyze, but such as needed to clarify some of the confusion over the assessment of risk.
The experience of the general public on controlling pests is limited to their house, yard, garden, and pets. Urban situations account for at least a quarter of all insecticides used. Consumers seem to have a wide acceptance of pesticides as long as they are the ones using them regardless of the fact that they are not professionals. The same people may indicate a distrust when these materials are in the hands of others even though they may be trained and licensed, and aware of the label regulations. There are also other factors that contribute to this distrust.
Most chemicals registered as pesticides are lab-synthesized, petroleum-based ingredients. Distrust of synthetic insecticides began in 1962 when the press featured stories about DDT contaminating fish causing fish-eating predator populations to decline as a result of thin egg shells. Later insecticides were the organo-phosphates and carbamate esters that were more biodegradable but had broad-spectrum toxicity and could affect non-target organisms. Some were highly target-specific and very safe such as carbaryl (Sevin) used in gardens and in flea collars for cats and dogs.
Most people do not understand pesticide products and therefor are uncomfortable with their use in food supplies. For instance, inhaling benzene fumes while filling up the car with gasoline poses a much greater health risk than irradiating food or administering growth hormones to cows. But, people are familiar with filling up their car with gasoline and the use of gasoline. They do not understand the actions of pesticides or appreciate their use very well.
The general public feels that they are far removed from the decision-making process that registers products or control of their exposure to them. Their experience with exposure is primarily due to mis-applications such as herbicide drift on the lawn, yard or garden or to bodily reactions because they spilled the concentrated product or sprayed it on themselves unintentionally. Interestingly germicidal pesticides, fungal ointments and bug repellents are widely accepted. But, again these are more familiar and their purpose clearer to the public. Also exposure is usually voluntary.
The public is also suspicious that not all the effects of chronic, long-term exposure are known. There are a few cases where this may have happened. For instance, it took many years for the environmental effects of chlorinated hydrocarbons to be fully understood. These cases are rare but not unique to agricultural chemical. Common and serious examples are lead in paint, recently re-appearing on children's toys from China, and asbestos in school buildings.
Surveys showed that just about every household in this country used some pesticide product within a year. Many homes are treated every year by pest control operators and yards treated by lawn care outfits. Pesticide products are applied with care, following labeled instructions, and few accidents occur. Factors that are responsible for the most deaths in this country, over 10,000 per year, are tobacco, alcohol, cars, murder, and falls. Of poisonings, pesticides accounted for 12 possible cases in 1988.
People often respond to risk irrationally, that is, not in agreement with statistical records on likelihood of hazard occurrence. One measure of risk used by governments is the chance of dying in any year of one individual out of a million. Under this measure, you would have a one in a million chance of dying in the coming year by traveling on a bicycle for 10 miles, in a car for 150 miles or in a jet plane for 3,500 miles, or even canoeing for six minutes. The same is true if you eat 40 tablespoons of peanut butter or have a chest X-ray. Surgery, X-rays and alcohol use are much more dangerous than pesticides, police work or privately flying a plane, however the public believes the opposite to be true. Risks are perceived based on low familiarity and high dread.
Chemicals synthesized in the laboratory or found in nature, such as glycoalkaloids, some can be hazardous and some safe. Some may be toxic and some not, and some may leave residue and some may not. Three significant conclusions can be discerned:
1. The biological activity of a chemical depends on its structure regardless of source.
2. Safety depends on the chemical structure and the way the chemical is used.
3. Perceived risk is often not consistent with actual risk but related to familiarity.