Assessment of pesticide residues in soil water and wells associated with an apple orchard and strawberry fields PDF
Preview Assessment of pesticide residues in soil water and wells associated with an apple orchard and strawberry fields
Digitized by the Internet Archive in 2010 with funding from Lyrasis IVIembers and Sloan Foundation http://www.archive.org/details/assessmentofpest709weav Assessment of Pesticide Residues in Soil Water and Wells Associated With an Apple Orchard and Strawberry Fields ti^L Bulletin 709T January 1993 Kgy\zu\iu'^a\ an^ Forestry Experiment Station y2L7 7 West Virginia University Authors Joseph E. Weaver is associate professor of entomology, Henry W. HogmireisprofessorofentomologyandJohnC.Sencindiverisprofessorof soil science, all in the College ofAgriculture and Forestry, West Virginia University. WestVirginiaUniversity AgriculturalandForestryExperimentStation CollegeofAgriculture andForestry RobertH.Maxwell,Director Morgantown Assessment of Pesticide Residues in Soil Water and Wells Associated With an Apple Orchard and Strawberry Fields Joseph E. Weaver, Henry W. Hogmire, and John C. Sencindiver INTRODUCTION Pesticidecontaminationofgroundwaterandsurfacewaterfromagricul- turalcroppingsystemsisanenvironmentalconcern.Somecrops,suchastree and small fruits, require intensive management to insure a pest-free or blemish-free product for marketing. Producing high-quality fruit typically requires the application ofpesticides on a calendar or growth-stage basis andaspestpressuredictates(12,16).Frequentapplicationofpesticides,use ofwater to prevent frost damage, andirrigationto supplywater duringdry periods all increase the potential for movement ofpesticides into ground- water2uidtooffsitelocationsthroughsubsoildrainagesystems.Inaddition, offsite movement ofpesticides can occur through runoff of contaminated surfacewaterfollowingrainfall.Thisisofspecialconcerninorchards,since asignificant portion ofthe tree fruit industryinWest Vu-gmiais located in hillyterrain. Pesticidesusedinfruitproduction canalso contaminatewells that provide the water used in spray appUcation. These wells are usually locatedatornearpesticide-mixingsiteswithinoradjacenttothecrop. Inafive-yearstudyofruralwellsinOntario,Canada, itwas foundthat pesticide contamination resulted from back-siphoning of spray solution, spills at the mixing site, and/or spray drift or surface runoff from field application(7).Outof40wellswithsuspectedcontaminationfrompesticides usedin orchards, ontobacco, or onvegetables, one shallowwell contained phosmet residues resultingfrom surface runofffollowing application in an orchard (7). A spill ofl,2-dibromo-3-chloropropane (DBCP) from a rusty can caused the contamination of a well associated with a South Carolina peach orchard (3). Nitrogen fertilizer can chemically contaminate wells throughleaching (15). Annuzil fertilizer appUcation in cherry orchards has resultedinnitrate-NcontaminationofwellsinnorthernMichigan(10). Limestone caverns can allowtheformation ofsinkholes thatprovide a direct route ("run-in") for thetransport ofpollutants togroundwater (15). Thepresenceofkarstterrain(cavernouslimestone)andresidentialdevelop- mentoforchardlandhaveresultedinincreasedconcernaboutwaterquality inthe easternpanhandleofWestVirgtnia. Accordingto anEnvironmentalProtectionAgencyreport (8), the im- pactofpesticidesusedinorchardcropsisnotgenerallyknown.Because of thislackofpublisheddata,thefrequentuseofpesticidesinfruitproduction, andthekarsttopographyintheeasternpanhandle, studieswereconducted toassesswaterquahtyinWestVirginiaorchards£uidstrawberryfields. Thisbulletinreportstheresultsofthreestudiesdesignedtoinvestigate thequahtyofsoilwaterinthevadosezone (toadepthof3ft)inanorchard and strawberry fields and in water from wells associated with orchards. Resultsofthestudies,whichwereconductedduring1984-86,arepresented as two sections in the bulletin: (1) Soil Water Studies and (2) WellWater Study. SOIL WATER STUDIES Procedures Site Descriptions APPLE ORCHARD The study was conducted in a 35-year-old commercial apple orchard nearRonmey(HampshireCounty),WestVirginia.Theorchardistypicalof productionareasfoundthroughoutthisuplandregionofWestVirginia.The predominant soil in the study area is Lehew channery fine sandy loam (loamy-skeletal, mixed, mesic Typic Dystrochrepts), a moderately deep well-drciinedsoil. The study site was situated in a drainage system comprising about 20 acres(A)(8ha)ofa30-A(12ha)orchardblock.Surfacewaterfromthearea drainedintotwosmallpondsneartheheadofonemajorravineandintothe ravine itself. At the end ofthe ravine, runoffwater entered a small stream about 1,200 ft (366 m) from the study site. Soil-water sampling sites were located on the two slopes leading into the ravine. Starting near the top of these slopes, three sites on each slope were selected at about equidistant intervals downslope for collecting soil-water samples within the orch£U"d. Twoadditionalsamplingsiteswerelocatedabout 105ft(32m) offsiteatthe headoftheravine. STRAWBERRY FIELDS The studywas conducted ontwo sites near Morgantown (Monongaha County),WestVirginia. OnestudyinvolvedvarietytrialslocatedonaWest A VirginiaUniversityfarmthatcontainedtwoplantingsofabout 1 (0.4ha) each. One planting was established in 1983 and the other in 1984. For discussion purposes, these are called the Old Planting and New Planting, respectively. The second study area was a commercial strawberry field A operatedonapick-your-ownbasis. Itcontainedplantingsofabout 1 (0.4 ha)eachinvariousyearsofproduction.Bothstudyareaswereunderlainwith adrainagesystematadepthofabout3ft(0.9m);effluentoutletswereabout 100ft (30m) offsite. ThesoilattheUniversityfarmsitewasTilsitsiltloam(fine-silty,mixed, mesic Typic Fragiudults), a deep, moderately well drained soU. At the commercial fields, the soils were Dormont silt loam (fine-loamy, mixed, mesic, UlticHapludalfs) and Guernseysilt loam (fine, mixed, mesicAquic Hapludalfs). Bothofthesesoilsare deepandmoderatelywelldrained. At the University farm, water samples were collected at four sites located about equidistant across each planting. At the commercial fields, sampleswerecollectedfromonlyonesitelocatedinthecenterofeachfield. Soil Water Sampling Sampleswere collectedwithasuctionlysimeter (Figure 1).Theuses of thesesamplers are discussedbyEverett et al. (6). Themethodofcollecting water from the samplers, however, was modified from the method given in the instructions provided with samplers. The modification was made to minimize the possibility ofpesticide contamination while the samplers re- mained in the study area and during sample collection. The modification consistedofinstallingapieceofteflontubingcuttothelengthofthesampler when attached to the short piece of tubing in the center of the stopper assembly.Thestopperassemblywasthentapedsecurelytothewatersampler A tube; thispreventedeasyremovalanddisturbanceofthe assembly. tight- fitting glass vial was also placed over the neoprene tube of each stopper assemblytoprevententryofdebris £mdspraymaterial. A 3-tn. (7.6 cm) diameter bucket auger was used for coring holes for sampler placement. Augered soil was separated in containers by depth of about 1 ft (0.3 m), thensiftedto remove pebbles androcks, and eachlayer replaced in sequence as backfill to tamp around the sampler. Samplers at theUniversityfarmwereinstalledingroupsoffourwitheachgroupcontain- ingasamplerset atadepthof6, 12, 24, and36in, (0.15,0.3, 0.6and0.8m) and spaced 2 ft (0.6 m) apart; at the commercial fields, only two samplers were used per field and set at depths of 24 and 36 in. Samplers at both locations were installed before anypesticides were applied for the season. The amount ofvacuum applied to samplersforwater collectionwas about 60 centibars (18 in. of mercury). Water was collected directly into 250-ml glass flasks that were cleaned by washing with alconox, triple rinsed with distilledwater,thenrinsedwithacetone.Afterdrying,theflasksweresealed withaluminumfoil. PlasticTube Vacuum Test Hand Pump Vacuum WaterSample Teflon Tubing Collected Soil-WaterSample Figure 1. SoilWaterSampler (courtesy,SoilmoistureEquipmentCorporation) Pesticide Applications APPLE ORCHARD Table 1 lists the types and amounts of pesticides applied to the study areaduringtheperiod 1983-1985whentheorchzirdwasmanagedimderan Integrated Orchard Management program. In addition, the following her- bicideswere appUedtothe uppermost part ofthe studyareain earlyApril 1985: terbacil80WplusdiuronSOWeachat 1.4kg/hainthefirstthreerows of trees; napropamide 50W plus paraquat CL at 8.96 kg and 0.95 L/ha, respectively,inthenext threerows oftrees. Theseherbicideswere apphed above the first set of water samplers over an area of about 0.6 ha each. Available records datingback to 1952showed that endrinwas appUedfive times annually to the study area for meadowvole control in November or December of1974, 1975, 1979, 1980, and 1981. Labelrecommendationsfor use ofendrinforvole controlare 1.34to 1.46kgactiveingredient (ai)/ha. STRAWBERRY FIELDS PesticideappUcationstotheUniversityfarmsitein1984wereaccording to West Virginia University Cooi>erative Extension Service recommenda- tions for establishment, maintenance, and pest control. These applications represented a "worst-case" scenario with treatments being made at label rateswhether ornottherewaspestpressure (Table2). The commercial field was managed according to current extension servicerecommendationsfor establishment, maintenance, andpest control for strawberryproduction. Fungicides andinsecticides were apphed on an as-neededbasis. Water Analysis A Baker-10 extraction system (J.T. Baker Chemical Co., Philhpsburg, NJ.)wasusedtoextractandconcentratepesticideresidues.Residueswere absorbedon6mloctadecyl(Cig) disposablecolumns, andwereelutedwith 1.5 or 2.0 ml of methanol. Water sample size varied from 100 to 200 ml. Pesticiderecoveryintheextractionstepwith200-nilsampleswasintherange of 79% to 100% for a variety of polar pesticides including terbadl and napropamide. Recovery ofendrin was between 58% and 67% since it was incompletelyelutedwithmethanolinthe standardprocedure. Pesticides were analyzed by gas chromatography using methods out- linedbytheU.S.EnvironmentalProtectionAgency(13, 14).Theidentityof endrinwas confirmedbyGC mass-spectrometry, aswell asbyits retention timewithdifferentabsorbants. Inroutine quantitationofendrin, theresults obtained with two different columns were compared. Pesticide concentra- tionsreportedforwatersamplesinthetables andtextarenotcorrectedfor estimatedrecoverylevels. Most water samples were extracted and concentrated on Cis columns atWest VirginiaUniversity and sent to the QuaHtyControl Division ofthe West Virginia Department of Agriculture (WVDA) for analysis. Some WVDA samples collected late in the season were sent directly to the laboratory for extraction and analysis. Some duplicate samples collected fromthestrawberryfieldswereanalyzedbyStauffer ChemicalCompany. Soil Sampling and Analysis APPLE ORCHARD Soil for analysis was collected at the surface (Q-l in.) and at 6, 12, 24, and 36 in. Samples from three random sites within the orchard and at one siteoutsidetheorchardwereanalyzedforendrin.Sampleswereairdriedat mm 23°Cfor24hoursinglasstrays.Driedsampleswerepassedthrougha5 sieve before analysis. Samples (about 10 g) were extracted with acetone- hexaneusingtheshakemethod,Endrinwasquantitativelydeterminedbythe methodsofNashetal,(9),Gaschromatographywasdonewitha1,5%OV-17 + 2,0%QF-1columnonly.AnalysesweredoneatWestVirginiaUniversity. STRAWBERRY FIELDS Soil samples from the Universitysite were collectedby the method of Schubertetal,(11).Onesoilcoresampletoadepthof3ft(0,9m)wastaken A fromeachgroupofwatersamplers, secondsimilarsamplewastakenata distanceofabout 10ft(3,0m) fromthefirstsampleinlinewiththegroupof water samplers. Samples were frozen and sent to Stauffer Chemical Com- panyforanalysis.Theprofileofanalysiswasfromnearthe surfaceto3ftat incrementsof0,5,6, 12,24, and36in.Soilsampleswere nottakenfromthe commercialsite. Results and Discussion Pesticide Residues in Soil Water APPLE ORCHARD Endrinwastheonlypesticidedetectedinwatercollectedfromsoilwater samplers. In 1985, 197 samples were collected from the orchard studysite (Table3),Ofthetotalnumbercollected,39(19.8%)werepositiveforendrin. Thenumberofpositivesamples,however,decreasedwithdepthwithpositive percentagesof27.1at6in.,24.5at12in., 15.7at24in.,and12.2at36in.The highestmeanconcentrationsoverallcollectiondateswerefoundatthe6and 12in. depths (2.92and2.01 ppb, respectively), while meanlevels at 24and 36 in. were much lower (1.32 and 1.23 ppb, respectively). The highest concentrationofendrindetectedwas 13,2ppbfroma6in,samplecollected on 11/8. Of 47 samples collected from the two offsite locations, only two (4.3%) were positive for endrin; these were samples at one site from the 6 in, depththatcontainedconcentrationsof <0,1 and0,5ppb. In 1986, only 13 samplers within the orchard produced collectable amountsofwaterfromAprilthroughmid-November.Allexcept oneofthe 13sampleswerefromthe6and12in.depth.Thesesampleswerepooledby depthwhenmore than one sampler containedwater. All samples,whether
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