Assessment of pesticide residues in soil water and wells associated with an apple orchard and strawberry fields

32 Pages·1993·0.98 MB·English

by  Weaver, Joseph E.

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