Pesticide Use: Environmental Risks and Alternatives by Jennifer Decker INTRODUCTION that the only longterm answer to pest control is through Of the 1.1 billion pounds of pesticide chemi- a highly complex "ecological approach" to farming. Id. cals used nationwide in 1984, seventy-seven percent at 17. or 861 million pounds were used in agriculture. The This article surveys problems with pesticide California Public Interest Research Group (CAL- use and a number of "ecological approaches" to PIRG) reports that sixty to eighty percent of pesti- fanning that are currently used or being tested by cides used are to enhance the cosmetic appearance, U.S. farmers. Some of these methods have been and not the life, of the produce. Agriculture Practices around for centuries and are being rediscovered in and the 1990 Farm Bill Hearings Before the Sub- this country; others are being developed through comm. on Conservation and Forestry and Comm. on university and government research programs. Agric., Nutrition and Forestry, U.S. Senate, Febru- These programs have a number of common benefits ary 9, 1990 (statement by Mr. Richard Reed, Califor- including their dramatic reduction pesticide usage nia Action Network). Nationally, eleven percent of and reduction of water waste from irrigation. Id. at the pesticides used are fungicides, twenty-three per- 17. cent are insecticides, and sixty-six percent are herbi- cides. Mattes, Kicking the Pesticide Habit, AMICUS THE PROBLEMS: HUMAN HEALTH AND Journal, Fall 1989, Volume 11, Number 4, p. 16. In THE ENVIRONMENT California alone, farmers use over ninety-three mil- Pesticide use affects the health of farm work- lion pounds of pesticides and nearly five billion ers and consumers and damages the environment. pounds of fertilizers each year. Agriculture Practices EPA's experts rank pesticides as a more serious and the 1990 Farm Bill Hearings Before the Sub- public health risk than hazardous waste sites. comm. on Conservation and Forestry and Comm. on Johnson, Congress Again Tries Rewriting Pesticide Agric., Nutrition and Forestry, U.S. Senate, Febru- Law, San FranciscoExaminer, July 31, 1987. Scien- ary 9, 1990 (statement by Ms. Jennifer Curtis, Re- tists, however, disagree about the degree of health search Associate of Natural Resources Defense danger from any given pesticide. Because EPA's Council). testing of over 600 chemical agents is decades behind Nationally, pesticide use has increased dra- schedule and terribly underfunded, answers will not matically in the latter part of this century, without a come quickly. corresponding reduction in pest damage. Pesticide The potential health problems from pesticide chemical use has increased thirty-three fold since exposure can be divided into two classes: acute 1945 (Hileman, Alternative Agriculture, Chemical effects and chronic effects. Acute effects result from and Engineering News, March 5, 1990, at 29), yet contact with high levels of a chemical over a short crop loss from insects has increased twofold, from duration, usually causing immediate signs of con- about seven percent to thirteen percent. Id. See also tamination. These effects include nausea, skin irrita- Mattes, Kicking the Pesticide Habit at 10. According tion, and other minor problems. U.S. Environmental to Dr. Pimentel, a professor of insect ecology and Protection Agency, Agricultural Chemicals in agricultural sciences at Cornell University, society Ground Water: Proposed Pesticide Strategy, Office turned to chemicals during the 1940's as an easy of Pesticides and Toxic Substances, December 1987, solution to agricultural pests. He believes society's p. 25. resulting reliance on a chemical solution to every pest Chronic effects from pesticide exposure are problem was misguided, creating costly environ- harder to document because of the long latency mental and health problems. Dr. Pimentel suggests period between exposure and the onset of symp- toms. Many effects are known, however, including Nationally, EPA's Superfund program has cancer, mutations, birth defects, and immunological halted any site investigation where non-point source problems. Scientists agree that there are risks from pesticide contamination is suspected. Contamina- drinking pesticide-laden ground water, but they are tion from legally applied pesticides is so widespread unsure about the exact health effects of low level that any attempt to cleanup the potential Superfund exposure to specific pesticides. Id. Although gaps sites would bankrupt the program's budget. exist in scientific data, there is consensus that pesti- Currently in California, approximately fifty-seven cide use is an endemic problem that threatens our different pesticides have been detected in groundwa- health. Currently, an average of three California farm ter, one-half of these being attributed to legal pesti- workers report pesticide poisoning each day, and cide application and one-half to point sources or officials estimate that at least eleven additional cases unknown causes. The result is that many Califor- of poisoning go unreported. Agriculture Practices nians risk greater pesticide exposure than people and the 1990 Farm Bill Hearings Before the Sub- from most other states. For example, nearly 700,000 comm. on Conservation and Forestry and Comm. on Californians may have been exposed to dibromo- Agric., Nutrition and Forestry, U.S. Senate, Febru- chloropropane (DBCP) in 1987 from 2500 DBCP- ary 9, 1990 (statement by Mr. Richard Reed, Califor- contaminated drinking water wells; sixty percent of nia Action Network). The general public is exposed these wells had levels above the State standard. Id. on a daily basis through fruit and vegetable con- at 22. California's environmental problems from sumption. We are further exposed through drinking pesticides are not unique. The state monitoring pesticide-contaminated water. programs only confirm the problems. In Long Is- land, New York, 1,000 aldicarb-contaminated wells PESTICIDES AND GROUND WATER contained levels about the state standard of 7 parts Pesticide monitoring began in the 1970's, and per billion (ppb). Id. at 22. In Florida, 1,200 drinking by 1986 nineteen different pesticides had been de- wells have been closed due to aquifer contamination; tected in ground water in twenty-four states. Today, ten percent of the public and private wells there twenty-six states report ground water contamination. contain ethylene dibromide (EDB). A 1986 Minne- Id. Most contamination comes from non-point sources, sota survey reported pesticide contamination in fifty- such as agricultural applications, rather than from spills two percent of 225 private wells. Id. at 22. or concentrated point sources. U.S. Environmental Protection Agency, AgriculturalChemicals in Ground MOVEMENT OF PESTICIDES FROM Water: Proposed Pesticide Strategy, Office of Pesti- THE TOP SOIL TO THE GROUNDWATER cides and Toxic Substances, December 1987, at 21-22. Natural factors, as well as agricultural practices, Pesticide-contaminated aquifers are particularly troub- affect the potential for pesticides to contaminate ground lesome where they are the primary or sole source of water. These factors include the physical properties of drinking water, such as in smaller communities (like the the chemicals and the soil, and climactic conditions. Island of Oahu); aquifer contamination means import- The chemical properties of the pesticides affect ing water at a great expense. their longevity in the soil and their rate of movement : Pete McDonnell From "RESOURCES- from the surface soil to the aquifer. For example, water Pesticide persistence in the soil also determines solubility determines a pesticide's propensity to dis- the longterm effect of these chemicals. Persistence is solve in water, making the chemical more able to mi- essentially a chemical's expected lifespan. It is meas- grate through the soil and into an aquifer. Hydrolysis is ured as the time required for one-half of the pesticide's the rate of degradation of a pesticide in water; if the residue to degrade to a non-detectable level. Persistence pesticide leaches below top layers of soil, beyond bio- is an inherent characteristic of the chemical itself. logical activity, hydrolysis becomes the only process Dragun, A ChemicalEngineer's Guide to Groundwater available to decompose a pesticide. Dragun, Kuffner, Contaminationat 66. and Schneiter, A Chemical Engineer's Guide to Once pesticides are sprayed onto a field, they Groundwater Contamination, Chemical Engineering, have the potential to migrate deep into the soil and Nov. 26, 1984, p. 6 6 . into the aquifers below. The downward movement of Once the soil and pesticides begin to interact, a pesticide in the soil is driven by competing proc- their combined chemical properties create molecular esses of degradation and leaching. Id. If the chemical reactions, forming new molecular bonds. Chemicals is degraded by biological or chemical processes tend to bind to soil particles in a process known as before it leaches, it never reaches the aquifer. If the adsorption, which slows the pesticide migration chemical has high persistence, is not degraded, and processes. Adsorption is most greatly affected by the also does not bind with soil, it is very likely to leach soil type, soil moisture, and soil organic matter con- into and contaminate the ground water. Id. tent. Id. at 67. Climactic conditions also greatly affect the This propensity for soils and pesticides to likelihood that pesticides in soils will reach the bond affects the rate of pesticide