Environmental Problems, Their Causes, and Sustainability 1

veloped countries, but use in developing countries issoaring.After growing rapidly, pesticide use on crops inthe United States has leveled off since 1980, but nonagriculturaluses have increased. About one-fourth ofpesticide use in the United States is for ridding houses,gardens, lawns, parks, playing fields, swimmingpools, and golf courses of pests.According to the U.S. Environmental ProtectionAgency (EPA), the average lawn in the United States isdoused with 10 times more synthetic pesticides perhectare than U.S. cropland. Golf courses get almost asmuch pesticide per hectare as lawns get. Childrenrolling around in the grass on treated lawns and in cityparks can pick up dangerous levels of some of thesechemicals. They are especially vulnerable because theyare still developing and can absorb more of thesechemicals in proportion to their body weight thanadults do. Health scientists warn that exposures tothese and other toxic chemicals early in life can increasethe risk of developing learning disabilities,behavioral problems, some forms of cancer, and otherchronic diseases in childhood and in adulthood. Pesticidecompany officials dispute such claims.The EPA also estimates that 84% of U.S. homesuse pesticide products such as bait boxes, pest strips,bug bombs, flea collars, pesticide pet shampoos, andweed killers. What pesticide products are used whereyou live?Sending someone roses, carnations, or other cutflowers is a nice gesture. Most of the cut flowers soldin the United States are imported from countries suchas Colombia and Ecuador. Bad news for romance. Accordingto a 1995 report by the World Resources Institute,flowers from these countries are heavily dosedwith fungicides, insecticides, and herbicides. Thisposes health threats to the tens of thousands of workers,most of them women, who work in flower farmsand greenhouses for about $5 a day. Environmentalistsurge us to buy organic flowers.*Some pesticides, called broad-spectrum agents, aretoxic to many species; others, called selective or narrowspectrumagents, are effective against a narrowly definedgroup of organisms. Pesticides vary in their persistence,the length of time they remain deadly in theenvironment (Table 23-1). In 1962, biologist RachelCarson warned against relying on synthetic organicchemicals to kill insects and other species we deempests (Individuals Matter, p. 27).*You can search for local farms, farmers’ markets, and communitygroups that supply fresh and dried organic flowers atwww.localharvest.org. There are not many organic flower growersin the United States, but this could change if the demandincreased.23-2 THE CASE FOR PESTICIDESWhat Are the Advantages of ModernSynthetic Pesticides? Many BenefitsModern pesticides save lives, increase foodsupplies, increase profits for farmers, work fast,and are safe if used properly.Proponents of conventional chemical pesticides contendthat their benefits outweigh their harmful effects.Conventional pesticides have a number of importantbenefits.They save human lives. Since 1945, DDT and otherchlorinated hydrocarbon and organophosphate insecticidesprobably have prevented the premature deaths ofat least 7 million people (some say as many as 500 million)from insect-transmitted diseases such as malaria(carried by the Anopheles mosquito), bubonic plague(carried by rat fleas), and typhus (carried by body liceand fleas).They increase food supplies. According to the UNFood and Agriculture Organization, about 55% of theworld’s potential human food supply is lost to pests—about two-thirds of that before harvest and the rest after.Pests before and after harvest destroy an estimated37% of the potential U.S. food supply; insects cause 13%of these losses, plant pathogens 12%, and weeds 12%.Without pesticides, these losses would be worse, andfood prices would rise. Figure 23-2 (p. 522) shows fiveof the most common insect pests in the United Statesand their ranges.They increase profits for farmers. Pesticide companiesestimate that every $1 spent on pesticides leadsto an increase in U.S. crop yields worth approximately$4 (but studies have shown this benefit dropsto about $2 if the harmful effects of pesticides areincluded).They work faster and better than alternatives. Pesticidescontrol most pests quickly at a reasonable cost,have a long shelf life, are easily shipped and applied,and are safe when handled properly by farm workers.When genetic resistance occurs, farmers can usestronger doses or switch to other pesticides.When used properly, their health risks are very lowcompared with their benefits. According to ElizabethWhelan, director of the American Council on Scienceand Health (ACSH), which presents the position of thepesticide industry, “The reality is that pesticides, whenused in the approved regulatory manner, pose no riskto either farm workers or consumers.” According tothe EPA, the worst-case scenario is that synthetic pesticidesin food cause 0.5–1% of all cancer-related deathsin the United States, or 3,000–6,000 premature deathsper year, far less than the estimated number of livessaved each year by pesticides.http://biology.brookscole.com/miller14521