SacramentoSacramento
San FranciscoSan Francisco
Sacramento River
Sacramento River
San Joaquin River
San Joaquin River
U.S. Department of the InteriorU.S. Geological Survey
Fact Sheet 2012–3132November 2012Printed on recycled paper
Understanding Pesticides in California’s Delta
Delta Watershed:
• 6millionpeople(2009estimate).
• 4millionacresagriculturalland.
• 400pesticidesappliedfortotalof10millionpoundseachyear.
DecadesofUSGSresearchhaveprovidedagoodunderstandingofwhen,where,andhowpesticidesentertheDelta.However,pesticideuseiscontinuallychanging.NewfieldstudiesandmethodsareneededsothatscientistscananalyzewhichpesticidesarepresentintheDelta,andatwhatconcentrations,enablingthemtoestimateexposureandultimateeffectsonorganisms.ContinuingresearchwillprovideresourcemanagersandstakeholderswithcrucialinformationtomanagetheDeltawisely.
Pesticide Sources
• Pesticidesareappliedinagriculturalandurbanareastocontrolunwantedinsects,plants,andfungi.
• Theamountandtypeofpesticidesusedchangesaspesticidesarewithdrawnfromthemarket,croppingpatternsandpestpressureschange,andnewchemicalsaredeveloped.
• Pesticideapplication,followedbyrunofffromrainorirrigation,createswell-definedseasonalpatternsofpesticideconcentrationsinDeltawaterchannels.
• WaterscarryingpesticidesentertheDeltafromtheSacramentoandSanJoaquinRivers,YoloBypass,surroundingcreeks,andwithin-Deltalands.
• ChangingwateruseandclimateaffectpesticideinputandtransportthroughtheDelta.
TheSacramento-SanJoaquinRiverDelta(Delta)isthehubofCalifornia’swatersystemandalsoanimportanthabitatforimperiledfishandwildlife.AquaticorganismsareexposedtomixturesofpesticidesthatflowthroughthemazeofDeltawaterchannelsfromsourcesincludingagricultural,landscape,andurbanpest-controlapplications.Whilewedonotknowalloftheeffectspesticideshaveontheecosystem,thereisevidencethattheycausesomedamagetoorganismsintheDelta.
WINTEROrchardsRainfall
SPRINGAlfalfa
Rainfall & Irrigation
SPRING-SUMMERRice
Field Water ReleaseSUMMER
Row/Truck CropsIrrigation
How do Pesticides Move into the Water?
Res
ulting in Distinct Seasons of Pesticide Occurrence
PESTICIDES ARE APPLIED
THEN TRANSPORTED BY WATER AND SEDIMENTS
INTO WATERWAYS
ALL YEARUrban Use
Rainfall & Irrigation
How Are Living Organisms Affected?Pe
stic
ide
Conc
entra
tion
Short time at high concentration
Long time at low concentration
Time
EXPOSURE = CONCENTRATION * TIME
CH2 Cl
S
O
N
CH3
H2C
H3C
H3C
CH2CH3
N
CH3
CHCH 2OCH 3
COCH 2CI
CH3
N
S
O
CH2
CH3
PESTICIDES Causes mortality or decreases growth
Changes quantity or quality of food
Direct Effects
Indirect Effects
ORGANISMS LIVING IN THE DELTA ARE EXPOSED TO
PESTICIDES
EFFECTS CAN BE DIRECT OR INDIRECT
Bothpesticideconcentrationandthelengthoftimethatanorganismisexposedtoapesticidedeterminetheeventualeffectithasontheorganism.SomepesticidesmovethroughtheDeltaquickly(hourstodays),butarepresentathighconcentrations.Otherpesticidesarepresentforlongerperiods(weekstomonths),butatmuchlowerconcentrations.Bothtypesofexposurecanaffectanorganism,soitisimportanttoknowspecificenvironmentalpesticideconcentrationsanddurations.
Themostobviouseffectofpesticideexposureonorganismsisdeath,usually,asaresultofdirectexposuretohighconcentrationsofpesticidesoverashorttime.But,exposuretolowerconcentrationsoveralongertimecanbejustasdeadly.Decreasedgrowth,impairedreproduction,andinhibitionofswimmingperformancecanalldiminishpopulationsize.Pesticidesintheenvironmentcanalsohaveindirecteffects,whichresultinproblemssuchasreductioninavailabilityorqualityoffood.
USGS Pesticide Fate Research Group
Waterisanalyzedbecausethisiswheremostanimalslive.Sedimentsareimportantfororganismsthatlivein,oratthebottomof,streams.Pesticidescanalso“moveupthefoodchain”asorganismseatanimalsorplantsthathavealreadyaccumulatedpesticides.Togainamorecompleteviewofenvironmentaleffectsofpesticidesonorganisms,weanalyzewater,sediments,andanimaltissue.
Effectivepesticideanalysisrequirespersistentmethoddevelopmentandresearch.TheUSGSPesticideFateResearchGroupisaleaderincurrent-usepesticidescience.ResearchersfrequentlyaddnewcompoundstoUSGSmethodstokeepupwithchangingpesticideuseandnewenvironmentalconcerns.Laboratorymethodsaresensitiveenoughtopreciselyandaccuratelymeasurepesticideconcentrationlevelsthatareverylowbutthatstillmayaffectlivingorganisms.
Authors:KathrynM.Kuivila,[email protected],andJamesL.Orlando,[email protected]
Contact:CaliforniaWaterScienceCenter;6000JStreet,PlacerHall;Sacramento,CA95819http://ca.water.usgs.gov/
For More Information:http://ca.water.usgs.gov/projects/toxics/DesignedbyYvonneRoque
Reference: Kuivila,K.M.andHladik,M.L.,2008.Understandingtheoccur-renceandtransportofcurrent-usepesticideintheSanFranciscoEstuaryWater-shed,SanFranciscoEstuaryandWatershedScience,v.6(3),article2.
Science to Help Resource ManagersSummarizing Our Current Understanding of Pesticides in the DeltaFourmajorseasonalpatternsofriverineinputsofpesticidestotheestuarywereidentifiedonthebasisofapplicationtimingandtransportmechanism.Incontrast,urbaninputstookplacethroughoutmuchoftheyear.Identifieddatagapsincludedthelackofanalysisofmanypesticides(ordegradates),changingpesticideuse,limitedinformationonpesticidetransportwithintheDelta,andanincompleteunderstandingofthetransportandpersistenceofsediment-associatedpesticides(KuivilaandHladik,2008).
State-of-the-ArtAnalyticalLaboratory
Proven Field SamplingMethodsUnderstanding
of Delta Hydrology
Knowledge of Pesticide-Use
Practices
Knowledge of Chemical
Processes
Continuing to Conduct Focused Research on PesticidesADAPTING TO CHANGING USEAspesticideusechangesandnewchemicalscomeonthemarket,thetimingandconcentrationsofpesticidesenteringtheDeltawillchange.Routinemonitoringandadvancedmethodstoanalyzenewpesticidesprovidecurrentinformationonthecomplexmixtureofpesticidespresentintheecosystem.
EVALUATING PESTICIDE FATEPesticidesenteringtheDeltacanbedissolvedinthewaterorattachedtosediments,andcanalsodegradetonewcompoundsofpotentialconcern.Focusedfieldandlaboratorystudiesprovideinformationonthefactorscontrollingtheseprocesses,whichinturninfluencethetransportandpersistenceofpesticides.
ASSESSING FISH EXPOSUREInthecomplexDelta,itisdifficultandexpensivetoadequatelycharacterizefishexposurebymeasuringpesticideconcentrationsinwaterandsediments.Adifferentapproachisto“askthefish”bydirectlyanalyzinglevelsofpesticidesandtheirmetabolitesinfishtissuewithsensitiveanalyticalmethods.
Through ongoing collaborations with toxicologists, ecologists, and fisheries biologists, we can address questions of concern such as “how do pesticides affect native fish populations in the Delta and the ecosystem as a whole?”
Using Our Expertise to Address Data Gaps