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<ul><li><p>Pesticide Use: EnvironmentalRisks and Alternatives</p><p>by Jennifer Decker</p><p>INTRODUCTIONOf the 1.1 billion pounds of pesticide chemi-</p><p>cals used nationwide in 1984, seventy-seven percentor 861 million pounds were used in agriculture. TheCalifornia Public Interest Research Group (CAL-PIRG) reports that sixty to eighty percent of pesti-cides used are to enhance the cosmetic appearance,and not the life, of the produce. Agriculture Practicesand the 1990 Farm Bill Hearings Before the Sub-comm. on Conservation and Forestry and Comm. onAgric., Nutrition and Forestry, U.S. Senate, Febru-ary 9, 1990 (statement by Mr. Richard Reed, Califor-nia Action Network). Nationally, eleven percent ofthe pesticides used are fungicides, twenty-three per-cent are insecticides, and sixty-six percent are herbi-cides. Mattes, Kicking the Pesticide Habit, AMICUSJournal, Fall 1989, Volume 11, Number 4, p. 16. InCalifornia alone, farmers use over ninety-three mil-lion pounds of pesticides and nearly five billionpounds of fertilizers each year. Agriculture Practicesand the 1990 Farm Bill Hearings Before the Sub-comm. on Conservation and Forestry and Comm. onAgric., Nutrition and Forestry, U.S. Senate, Febru-ary 9, 1990 (statement by Ms. Jennifer Curtis, Re-search Associate of Natural Resources DefenseCouncil).</p><p>Nationally, pesticide use has increased dra-matically in the latter part of this century, without acorresponding reduction in pest damage. Pesticidechemical use has increased thirty-three fold since1945 (Hileman, Alternative Agriculture, Chemicaland Engineering News, March 5, 1990, at 29), yetcrop loss from insects has increased twofold, fromabout seven percent to thirteen percent. Id. See alsoMattes, Kicking the Pesticide Habit at 10. Accordingto Dr. Pimentel, a professor of insect ecology andagricultural sciences at Cornell University, societyturned to chemicals during the 1940's as an easysolution to agricultural pests. He believes society'sresulting reliance on a chemical solution to every pestproblem was misguided, creating costly environ-mental and health problems. Dr. Pimentel suggests</p><p>that the only longterm answer to pest control is througha highly complex "ecological approach" to farming. 17.</p><p>This article surveys problems with pesticideuse and a number of "ecological approaches" tofanning that are currently used or being tested byU.S. farmers. Some of these methods have beenaround for centuries and are being rediscovered inthis country; others are being developed throughuniversity and government research programs.These programs have a number of common benefitsincluding their dramatic reduction pesticide usageand reduction of water waste from irrigation. Id. at17.</p><p>THE PROBLEMS: HUMAN HEALTH ANDTHE ENVIRONMENT</p><p>Pesticide use affects the health of farm work-ers and consumers and damages the environment.EPA's experts rank pesticides as a more seriouspublic health risk than hazardous waste sites.Johnson, Congress Again Tries Rewriting PesticideLaw, San Francisco Examiner, July 31, 1987. Scien-tists, however, disagree about the degree of healthdanger from any given pesticide. Because EPA'stesting of over 600 chemical agents is decades behindschedule and terribly underfunded, answers will notcome quickly.</p><p>The potential health problems from pesticideexposure can be divided into two classes: acuteeffects and chronic effects. Acute effects result fromcontact with high levels of a chemical over a shortduration, usually causing immediate signs of con-tamination. These effects include nausea, skin irrita-tion, and other minor problems. U.S. EnvironmentalProtection Agency, Agricultural Chemicals inGround Water: Proposed Pesticide Strategy, Officeof Pesticides and Toxic Substances, December 1987,p. 25.</p><p>Chronic effects from pesticide exposure areharder to document because of the long latencyperiod between exposure and the onset of symp-</p></li><li><p>toms. Many effects are known, however, includingcancer, mutations, birth defects, and immunologicalproblems. Scientists agree that there are risks fromdrinking pesticide-laden ground water, but they areunsure about the exact health effects of low levelexposure to specific pesticides. Id. Although gapsexist in scientific data, there is consensus that pesti-cide use is an endemic problem that threatens ourhealth. Currently, an average of three California farmworkers report pesticide poisoning each day, andofficials estimate that at least eleven additional casesof poisoning go unreported. Agriculture Practicesand the 1990 Farm Bill Hearings Before the Sub-comm. on Conservation and Forestry and Comm. onAgric., Nutrition and Forestry, U.S. Senate, Febru-ary 9, 1990 (statement by Mr. Richard Reed, Califor-nia Action Network). The general public is exposedon a daily basis through fruit and vegetable con-sumption. We are further exposed through drinkingpesticide-contaminated water.</p><p>PESTICIDES AND GROUND WATERPesticide monitoring began in the 1970's, and</p><p>by 1986 nineteen different pesticides had been de-tected in ground water in twenty-four states. Today,twenty-six states report ground water contamination.Id. Most contamination comes from non-point sources,such as agricultural applications, rather than from spillsor concentrated point sources. U.S. EnvironmentalProtection Agency, Agricultural Chemicals in GroundWater: Proposed Pesticide Strategy, Office of Pesti-cides and Toxic Substances, December 1987, at 21-22.Pesticide-contaminated aquifers are particularly troub-lesome where they are the primary or sole source ofdrinking water, such as in smaller communities (like theIsland of Oahu); aquifer contamination means import-ing water at a great expense.</p><p>Nationally, EPA's Superfund program hashalted any site investigation where non-point sourcepesticide contamination is suspected. Contamina-tion from legally applied pesticides is so widespreadthat any attempt to cleanup the potential Superfundsites would bankrupt the program's budget.</p><p>Currently in California, approximately fifty-sevendifferent pesticides have been detected in groundwa-ter, one-half of these being attributed to legal pesti-cide application and one-half to point sources orunknown causes. The result is that many Califor-nians risk greater pesticide exposure than peoplefrom most other states. For example, nearly 700,000Californians may have been exposed to dibromo-chloropropane (DBCP) in 1987 from 2500 DBCP-contaminated drinking water wells; sixty percent ofthese wells had levels above the State standard. 22. California's environmental problems frompesticides are not unique. The state monitoringprograms only confirm the problems. In Long Is-land, New York, 1,000 aldicarb-contaminated wellscontained levels about the state standard of 7 partsper billion (ppb). Id. at 22. In Florida, 1,200 drinkingwells have been closed due to aquifer contamination;ten percent of the public and private wells therecontain ethylene dibromide (EDB). A 1986 Minne-sota survey reported pesticide contamination in fifty-two percent of 225 private wells. Id. at 22.</p><p>MOVEMENT OF PESTICIDES FROMTHE TOP SOIL TO THE GROUNDWATER</p><p>Natural factors, as well as agricultural practices,affect the potential for pesticides to contaminate groundwater. These factors include the physical properties ofthe chemicals and the soil, and climactic conditions.</p><p>The chemical properties of the pesticides affecttheir longevity in the soil and their rate of movement</p><p>: Pete McDonnell From "RESOURCES-</p></li><li><p>from the surface soil to the aquifer. For example, watersolubility determines a pesticide's propensity to dis-solve in water, making the chemical more able to mi-grate through the soil and into an aquifer. Hydrolysis isthe rate of degradation of a pesticide in water; if thepesticide leaches below top layers of soil, beyond bio-logical activity, hydrolysis becomes the only processavailable to decompose a pesticide. Dragun, Kuffner,and Schneiter, A Chemical Engineer's Guide toGroundwater Contamination, Chemical Engineering,Nov. 26, 1984, p. 6 6 .</p><p>Once the soil and pesticides begin to interact,their combined chemical properties create molecularreactions, forming new molecular bonds. Chemicalstend to bind to soil particles in a process known asadsorption, which slows the pesticide migrationprocesses. Adsorption is most greatly affected by thesoil type, soil moisture, and soil organic matter con-tent. Id. at 67.</p><p>This propensity for soils and pesticides tobond affects the rate of pesticide migration in differenttypes of soils. For example, clay soils have a highsurface area which encourages adsorption. Id. Thechemical properties of clay allow positively-chargedchemicals to easily bind with the clay fraction in thesoil. The percentage of clay or sand or silt in the soilis called the soil texture. Soil texture affects thepesticide's ability to leach, moving slowly in fine orcement-like clay soils, and more quickly and deeperin course or light soils. Agricultural Chemicals inGround Water: Proposed Pesticide Strategy, EPA,Office of Pesticides and Toxic Substances, Decem-ber 1987, p. 22. The larger structure of soils also affectstheir propensity to bind with chemicals or allow chemi-cals to readily pass by. Large soil structure is deter-mined by the way soil particles bind together into largerunits. Dragun, Kuffner, and Schneiter, A ChemicalEngineer's Guide to Groundwater Contamination at 66.</p><p>The most simple soils are made of uniformgrains. However, soils can also bind themselves intoplates or clumps or other shapes. The manner in whichthe soil clumps contributes to the propensity for waterand dissolved pesticides to migrate through spacesbetween the clump. The more pore space betweensoil groupings the higher the porosity; the higher theporosity of the soil, the quicker the percolation ofpesticides toward the aquifers. Agricultural Chemi-cals in Ground Water: Proposed Pesticide Strategyat 22.</p><p>Pesticide persistence in the soil also determinesthe longterm effect of these chemicals. Persistence isessentially a chemical's expected lifespan. It is meas-ured as the time required for one-half of the pesticide'sresidue to degrade to a non-detectable level. Persistenceis an inherent characteristic of the chemical itself.Dragun, A Chemical Engineer's Guide to GroundwaterContamination at 66.</p><p>Once pesticides are sprayed onto a field, theyhave the potential to migrate deep into the soil andinto the aquifers below. The downward movement ofa pesticide in the soil is driven by competing proc-esses of degradation and leaching. Id. If the chemicalis degraded by biological or chemical processesbefore it leaches, it never reaches the aquifer. If thechemical has high persistence, is not degraded, andalso does not bind with soil, it is very likely to leachinto and contaminate the ground water. Id.</p><p>Climactic conditions also greatly affect thelikelihood that pesticides in soils will reach thegroundwater. One of the most important variables isthe amount of precipitation in the area. As rain fallsonto the soil, the rain water binds with the chemicalsand carries them through the soil particles to theground water below. Air temperatures compete withthis process since evaporation reduces the wateravailable for migration. Id. The depth of the aquiferfrom the surface soils is also key to how quickly anaquifer can become polluted. Agricultural Chemicalsin Ground Water: Proposed Pesticide Strategy at 35-37.</p><p>AGRICULTURAL PRACTICES AFFECT-ING PESTICIDE CONTAMINATION</p><p>Many agricultural practices affect the level ofenvironmental contamination from pesticide use.These practices include:</p><p>* Application Rates: The amount of pesti-cides applied correlates directly with the amount ofpesticides available for leaching into the soils andgroundwater.</p><p>* Timing of Application: Timing the sprayingrelative to rainfall events, season of the year, and thepresence or absence of a crop affects the net amountof chemicals reaching the soil. Id. at 36.</p><p>* Method of Application: Pesticides are ap-plied in a number of ways. These include sprayingthem directly on the crops or on bare soil, dissolvingthem in irrigation water, or injecting the chemicals</p></li><li><p>beneath the soil surface. Subsurface injection and directsurface spraying are the methods most likely to contami-nate groundwater. Id. at 36-37.</p><p>* Cultivation Practices: Tillage used to de-crease soil erosion can increase a soil's porosity,which hastens the percolation of soluble pesticides.</p><p>* Irrigation: Irrigated soils are highly perme-able. The amount of irrigation water commonlyreaching subsurface soil is estimated to be twenty toforty percent of the applied water. Id. at 39. As thiswater leaches, it carries the soluble pesticides andtheir residues with it.</p><p>* Aerial Application: The common practice ofspraying pesticides from aircraft spreads the chemi-cals where they are not needed. Only 0.1 percent ofthe chemicals applied reach their actual target.Mattes, Kicking the Pesticide Habit at 10.</p><p>* Affects of Pesticide Use: Pesticides createthe need for more pesticides. Insecticides breedinsecticide-resistant insects and kill bugs' naturalenemies. Herbicides and fungicides create resistantweeds and pathogens. They also may increase thesusceptibility of crops to insects and disease. Id. at 10.</p><p>Six crops account for about ninety percent ofpesticide applications. These are alfalfa, corn, cot-ton, sorghum, soybeans, and wheat. This concentra-tion of pesticide use on a few major crops means that theapplication is heavily concentrated in certain major</p><p>agricultural areas. Herbicides currently form the largestand most rapidly growing class of pesticides. Applica-tions of herbicides now account for nearly ninety per-cent of the acreage of all major crops treated. Agricul-tural Chemicals in Ground Water: Proposed PesticideStrategy at 31.</p><p>COSTS OF PESTICIDE USAGEAND CONTAMINATION</p><p>Pesticide use costs a great deal in terms of theaffects on public health, farm workers' lifespans,damages to the ecosystem, and food costs. Croplosses, decline in property values, medical costs, andlaw suits are just a few of the other indirect costsresulting from pesticide use. According to Dr. Pi-mentel, a conservative estimate suggests that theenvironmental and social costs of pesticide use in theU.S. amount to about $1 billion annually; the poten-tial costs are much higher. Mattes, Kicking thePesticide Habit at 12.</p><p>Measuring the costs of pesticide usage tosociety is a difficult task. A USDA report by Nielsonand Lee in 1987 estimated the costs of avoiding risksimposed by pesticides in ground-water contamina-tion. Household well water monitoring costs alonewere an estimated $1.4 billion. Installing home-watertreatment units or obtaining alternative drinkingwater supplies are viable options, but the costs arehigh. Agricultural Chemicals in Ground Water:Proposed Pesticide Strategy at 26.</p><p>Cleanup of all point-source contaminatedaquifers is not economically feasible. Cleaning upnonpoint sources resulting from pesticide applica-tion would be even more expensive and may not betechnol...</p></li></ul>


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