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PreparedbyKathyDerouin,GroupHSE-8

DISCLAIMER

Thisreport waspreparedasan accountof work sponsoredby an agencyof the UrdtedStatesGoverrrrnent.Neitherthe United StatesGovernmentnor any agencythereof,nor any of their employees,makesarrywarranty,expressor implied,or assumesany legalliability or responsibilityfor the accuracy,completeness,or usefulnessof any information,appratus, producf,or processdisclosed,or representathat its usewouldnot irrfringeprivatelyownedrightyReference hereirsto any speciticcommercialproduct,process,orserticeby tradename,trademark,manufacturer,or otherwise,doesnot neccsarilyconstituteor imply itsendorsement,recommen&tion,or favoringby the UnitedStatesCoverramentor any agencythereof. Theviewsarrdopinionaof authorsexpressedhereindo not necessarilystateor reflectthoseof the UnitedStatesGovernmentor any agencythereof.

LA-10256-MS

Uc-11Issued:June1985

RadiologicalSurvey and Evaluationof theFalloutArea from the TrinityTest:

Chupadera Mesa and White SandsMissile Range, New Mexico

Wayne R. HansenJohn C. Rodgers

—— .— --

. ,. ...

. .

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—

,..,

ABOUT THIS REPORTThis official electronic version was created by scanning the best available paper or microfiche copy of the original report at a 300 dpi resolution. Original color illustrations appear as black and white images.

For additional information or comments, contact: Library Without Walls Project Los Alamos National Laboratory Research LibraryLos Alamos, NM 87544 Phone: (505)667-4448 E-mail: lwwp@lanl.gov

CONTENTS

ABSTRACT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

CHAPTER1—SUMMARY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

CHAPTER2—INTRODUCTIONANDBACKGROUND . . . . . . . . . . . . . . . . . . . . . 5

I. THEDOERESURVEYPROGRAM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

II. THETRINITYTEST. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

III. THETRINITYFALLOUTZONE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Iv. THERESURVEYOBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

CHAPTER3—METHODSANDAPPROACH . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

I APPROACH. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

H. METHODS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11A. 1nSituMeasurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11B. SamplingandAnalysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

CHAPTER4—RESULTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

I. TOTALAREA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14A. TrinityDataAnalysis:137CsinSoil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14B. TrinityDataAnalysis:23~2@PuinSoil . . . . . . . . . . . . . . . . . . . . . . . . . . . 18C. Other Fissionand ActivationProducts inSoils . . . . . . . . . . . . . . . . . . . . . . 20D. NaturalRadioactivityinSoils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

II, DATASUMMARYFORSOIIJ3 . . . . . . . . . .......;. . . . . . . . . . . . . . . 24A. PlutoniuminSoils . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24B. Cesium-137inSoiIs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25C. Strontium-90inSoils. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

111 AIRBORNERADIOACTIVEMATERIALS. . . . . . . . . . . .’....... . . . . . . . 27

IV. EXTERNALPENETRATINGRADIATION . . . . . . . . . . . . . . . . . . . . . . . . . 29

CHAPTER5—POTENTIALDOSEEVALUATION ANDINTERPRETATION. . . . . . . . . 40

I. BASESOFDOSEESTIMATESANDCOMPARISONS . . . . . . . . . . . . . . . . . . . 40

H. POTENTIALDOSESFROMTHECURRENTCONDITIONSINTHETRINITYTESTFALLOUTDEPOSITIONAREAS . . . . . . . . . . . . . . . . . . . . . 43

111 SPECIALCONSIDERATIONS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

v

REFERENCES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45ACRONYMSANDABBREVIATIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48UNITS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49GLOSSARY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

APPENDIXA—DATABASETRINDAT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52APPENDIX B—LOGOFFIELDOPERATIONS FORSURVEYOF

TRINITY, 1977. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82APPENDIXC—INSITUINSTRUMENTCALIBRATION. . . . . . . . . . . . . . . . . . . . . 86APPENDIXD—INTERPRETATIONOFDATA. . . . . . . . . . . . . . . . . . . . . . . . . . . 91APPENDIXE—SOURCESANDEVALUATIONOFRADIATION

EXPOSURES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110

FIGURES

1. CentralNew Mexico.Thesite of the Trinity Test isnoted ontheleftpartofthemap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

2. Trinitytesttower.OscuraMountainsinthebackground . . . . . . . . . . . . . . . . . . . . . 73. Rangeaftertest . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84. DiagramofTrinityGZfences . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95. The falloutzonefromtheTrinity testasdeterminedbya 1945

beta-gammasurvey. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96. Outline mapofthecontaminatedarea as determinedly 1947and 1948

survey.Atransectwas establishedwith numbered laterals . . . . . . . . . . . . . . . . . . . . 107. General mapofthe Tnnityfallout areaand the measurementlocations . . . . . . . . . . . . 148. Comparisonofinsitu and soilsampleestimatesof total ‘37CSinventory . . . . . . . . . . . . 209. WhiteSands MissileRange,Bingham,and Chupadera Mesasample locations. . . . . . . . . 25

10. Samplelocationsfor the San Antonio area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2511. Externalradiation dose rates measuredat Trinity Site,June 9, 1983to June 23, 1983. . . . . 39

C-1. N~/$ as a functionofa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88C-2. Nr/s= Nr/+ . 4/s as a function ofa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89D-1. LocationofJune 1983sampling. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93

TABLES

I.

II.III.IV.v.

VI.VII.

VIII.Ix.

x.XI.

XII.

XIII.

XIV.xv.

XVI.

XVII.XVIII.

XIX.xx.

XXI.

XXII.XXIII.

XXIV.

xxv.

XXVI.

XXVII.

C-I.

D-I.

D-II.

D-III.

D-IV.D-V.

ESTIMATESOF RISK BASEDON EXPOSURESATTRIBUTABLETO RESIDUALCONTAMINATION IN AREASOF FALLOUTFROM THE TRINITY TEST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3RISK COMPARISONDATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4137SOIL CONCENTRATION DATA. . . . . . . . . . . . . . . . . . . . . . . - . 16

CHUPADERAMESA 137CSPROFILEDATA. . . . . . . . . . . . . . . . . . . . 17GROUND ZERO TO CHUPADERA MESA137CSPROFILE DATA . . . . . . . 18137CSINVENTORy ~T1MATES. . . . . . . . . . . . . . . . . . . . . . . . . . . 18

COMPARISONOF IN SITU AND SOIL SAMPLEESTIMATESOF 137c5T’(_jTALINvENTORy . . . . . . . . . . . . . . . . . . . . . . . . . . -- 19TRINITY SOILCONCENTRATION OF 239”240pu.. . . . . . . . . . . . . . . . . 21GZ ENVIRONSAND CHUPADER4 MESA239’2@puSOILCONCENTRATION PROFILE ESTIMATES. . . . . . . . . . . . . . . . . . . . 22SURFACESOILCONCENTRATION OF238PUAND 238s239puRATIOS . . . . . 221977ESTIMATESOF l-cm AND TOTAL PLUTONIUM INVENTORY. . . . 23ACTIVATIONAND FISSIONPRODUCTS IN BULK SOIL SAMPLESAT TRINITY GZ AREA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23SOILCONCENTRATIONS OF NATURALLY OCCURRINGGAMMA-EMITTERS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24GROUND ZERO SURFACEMEASUREMENTS . . . . . . . . . . . . . . . . . 26WHITE SANDSMISSILERANGE FALLOUT ZONE SOILMEASUREMENTS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28BINGHAM AREASOIL MEASUREMENTS,US HIGHWAY 380CORRIDOR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29CHUPADER4 MESASURFACESOIL MEASUREMENTS . . . . . . . . . . . 30FAR FALLOUT ZONE SURFACESOIL MEASUREMENTS. . . . . . . . . . . 31SANANTONIO AREASURFACESOIL MEASUREMENTS. . . . . . . . . . . 32AREALCONCENTRATIONS OF 137CS. . . . . . . . . . . . . . . . . . . . . . . 33CHUPADERA MESAIN SITU ‘37CSDATA FOR SOILSBYLAND FORM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34$QSrBACKGROUND INFORMATION . . . . . . . . . . . . - . . . . . . . . . . 35POTENTIAL CONTRIBUTIONS OF RESUSPENSIONOF ‘gpuAIRBORNE RADIOACTIVITY. . . . . . . . . . . . . . . . . . . . . . . . . . . . 36EXTERNAL RADIATION EXPOSURE SUMMARY FORIN SITU DATA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37EXTERNAL PENETRATING R4DIATION MEASUREMENTSANDESTIMATESOF CONTRIBUTIONS FROM TRINITY FALLOUT. . . . . . . 38STANDARDSAND GUIDES FOR RADIATION ANDRADIOACTIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41INCREMENTALDOSES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

COUNT RATE PER UNIT FLUX AT THE DETECTOR, N~/& ASAFUNCTION OF MEASUREDa. . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

NORTHERN NEW MEXICO BACKGROUND REFERENCEVALUESFOR NATUR4LOR FALLOUT LEVELSOF RADIOACTIVITY . . . . . . . . 921983PLUTONIUM DATA FOR SPLIT SPOON CORE SAMPLESFROM GROUND ZERO AREA . . . . . . . . . . . . . . . . . . . . . . . . . . . 9419831S2EUDATA FROM SPLIT SPOON CORE SAMPLESINGROUND ZERO AREA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95JUNE 1983PLUTONIUM DATA FROM TRINITY GZAREA . . . . . . . . . 96PARAMETERSFOR ESTIMATIONOF RESUSPENSIONOF RADIO-NUCLIDES USING MASSLOADING. . . . . . . . . . . . . . . . . . . . . . . . 97

vii

D-VI.D-VII.

D-VIII.

D-IX.D-X.

D-XI.D-XII.

D-XIII.

D-XIV.

ENRICHMENT FACTORSFOR RESUSPENDABLEPARTICLES . . . . . . . 98INHALATION DOSE FACTORSUSED. . . . . . . . . . . . . . . . . . . . . . . 99ESTIMATEDDOSESFROM INHALATION OF AIRBORNEMATERIALSFROM RESUSPENSION . . . . . . . . . . . . . . . . . . . . . . . 100INPUT PARAMETERSFOR DOSE CALCULATIONS. . . . . . . . . . . . . . 101INGESTION DOSEFACTORSUSED . . . . . . . . . . . . . . . . . . . . . . . . 102INGESTED RADIONUCLIDES . . . . . . . . . . . . . . . . . . . . . . . . . . . 103ESTIMATEDDOSESFROM INGESTION OF FOODS GROWNIN EACHAREA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 104ESTIMATEDAIR CONCENTRATION FOR SOIL PREPARATIONFOR HOME GARDEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105ESTIMATEDOSESFROM SOIL PREPARATION FORHOME GARDEN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 106

E-I. RADIOACTIVEMATERIALSOF PRIMARY INTEREST IN THERADIOLOGICALSURVEY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113

E-II. UNITS OF RADIOACTIVITYUSED IN THE RADIOLOGICALSURVEY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 115

E-III. STANDARDSAND GUIDES FOR RADIATION ANDRADIOACTIVITY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

...VIII

This series of reports results from a program initiatedin 1974 by the Atomic Energy Commission(AEC) for determinationof the conditionof sites formerlyutilizedby the Manhattan EngineerDistrict(MED) and the AEC for work involvingthe handlingof radioactivematerials.Sincethe early 1940s,thecontrolof over 100sitesthat were no longerrequiredfor nuclear programshas been returned to privateindustryor the publicfor unrestricteduse. A searchof MED and AEC recordsindicatedthat for someofthesesites,documentationwas insufficientto determinewhetheror not the decontaminationworkdone atthe timenuclearactivitiesceasedis adequateby current guidelines.

This report contains data and information on the resurvey effort and the effect of residualcontaminationas a resultof nuclear weaponsdevelopmentprograms conductedin this area. The reportdocumentsthe present radiologicalconditionswithinthe realm of today’s sophisticatedinstrumentationand the impacton any future area development.

This report was prepared by the EnvironmentalSurveillanceGroup (HSE-8), Health, Safety andEnvironmentDivisionof Los Alamos National Laboratory. This report was compiledand written byWayneR. Hansen andJohn C. Rodgerswithmajor contributionsfrom WilliamD. Purtymun,DonaldM.Van Etten, John D. Purson and KennethH. Rea, Field work in 1977was directedby DanielW. Wilson.Field in sifu measurementsand laboratory sample countingwere directedby John Kirby and DouglasSever of Lawrence LivermoreNational Laboratory. Other Los Alamos personnelinvolvedin measure-ments were Thomas E. Hakonson, John W. Nyhan, Edward Rahrig, Thomas E. Buhl, and Alan K.Stoker.

ix

Radiological Survey and Evaluation of theFallout Area from the Trinity Test:

Chupadera Mesa and White Sands Missile Range, New Mexico

by

Wayne R. Hansen and John C. Rodgers

ABSTRACT

Current radiologicalconditionswereevaluatedfor the siteof the frst nuclearweaponstest, theTrinitytest, and the associated falloutzone. The tes~ locatedon White Sands MissileRange, was conductedaspart of the research with nuclear materials for the World War II Manhattan EngineerDistrict atomicbomb project.Someresidualradioactivityattributableto the testwas foundin the soilsof Ground Zero onWhiteSandsMissileRange and the areas that receivedfalloutfromthe test.The studyconsideredrelevantinformationincludinghistoricalrecords, environmentaldata extendingback to the 1940s,and new dataacquiredby fieldsamplingand measurements.Potentialexposuresto radiationwereevaluatedfor currentland uses. Maximumestimateddoseson Chupadera Mesa and other uncontrolledareas are less than 39’.of the DOE Radiation Protection Standards(RPSS).Radiationexposuresduringpublicvisitsto the U.S.Army-controlledGround Zero area are lessthan 1mremper annualvisitor lessthan 0.2% of the RPS fora memberof the public.Detaileddata and interpretationsare providedin appendixes.

This evaluationof current conditionsat the site of thefirst nuclear weapon test (Trinity) and the associatedfallout areas is based on extensivefield measurementsand samplingfollowedby interpretationof the resultingdata. The study was completedas part of the FormerlyUtilized Sites Remedial Action Program (FUSRAP)sponsoredby the U.S. Departmentof Energy(DOE).

The Trinitytest was part of the researchconductedforthe World War II Manhattan EngineerDistrict (MED)atomicbombproject.The test was conductedon July 16,1945.Measurementsof radiation levelsat Ground Zero(GZ) and in the fallout zone began the same day. Thefallout was blown in a northeast direction over WhiteSands Missile Range, Chupadera Mesa, and otherranchingareas. The land usesin the falloutzone remainthe same today. White Sands Missile Range extendsnorth of GZ about 17 km (10 miles).Privately ownedranch land extendsalong the path of the falloutzone tothe northeast with Chupadera Mesa areas of interestatabout 50 km (30 miles)northeast of GZ. Land use onChupadera Mesa is for cattle grazing.Areas farther outin the fallout area also are used for cattle grazing withsmallareas of crop production.

This study considered all availablerelevant informa-tion. Records and reports provided the history of themeasurementsof radiation and radioactivityat GZ andthe falloutzone. Environmentalmeasurementsand sam-ple results, some extending back to the 1940s, werereviewedfor informationon trends and patterns. Datafrom these and special radioecology research studieswerecompiledto providea basisfor planningthe acquisi-tion of newdata. Mostof the newdata consistof severalhundred field measurements and samples of soil andvegetation.

The tindings,based on interpretationof the dat~ areexpressed in this summary as maximum incrementsofrisk to hypotheticalindividualsexposed to the existingconditions.Individualrisks of cancer from exposure toradiation were calculatedfrom factors derivedfrom theNational Academy of Sciences 1980 study. Potentialexposuresto radiation for various possiblemechanismswere generally calculated as 50-year committed dose

2

equivalentsresultingfrom l-year exposuresto accountfor cumulative doses from those radioactive materialsretained in the body for varying periods after initialexposure. Exposure to natural background results inexactlythe samekindof risks.The risk-estimatingfactorswere applied to natural background radiation asmeasured in north central New Mexico to provideonecontextforjudgingthe significanceof other risks.Peopleliving in northern New Mexico incur an estimated in-cremental risk of cancer mortality of 8 chances in10 000, or a probability of 8 x 10-4, from a 50-yearexposureto the natural radiation background.The natu-ral radiation background dose, about 150 mrem eachyear, includescontributionsfrom cosmicradiation,natu-ral terrestrial radioactivity, and natural radioactivityincorporatedin the body. A larger perspectiveis that theoverall U.S. population lifetimerisk of mortality fromcancers induced by all causes is currently about 2chances in IO,or a probabilityof 0.2.

The maximum likely incremental risks from allmechanismsof potential exposure in the areas havingresidualradioactivityattributableto the residualradioac-tivityrange from about 2 chancesin 10 000(2 x 10-4)inthe-restricted use area to a minimumof 6 chances in10 000 000 000(6 x 10-1”)under current conditionsofland use as summarized in Table I. The mechanismsinclude direct exposure to penetrating radiation andinhalationof resuspendeddust.

Table I givesthe incrementalrisksof cancer mortality,bone cancer, and lung cancer, along with the 50-yeardose commitmentsfrom which they were calculated.Allof the dosecommitmentvaluesare consideredoverstatedto some degree because assumptionsused in their deri-vation were made to maximize estimates of potentialeffects.All of the dose commitmentsare small fractionsof those permitted above natural background andmedical exposure by the DOE Radiation ProtectionStandards (RPSS). Maximum estimated doses onChupadera Mesa and other uncontrolledareas are lessthan 3% of the RPSS.

Another context for judging the significanceof theserisksassociatedwithexposureto radiation,whetherfrom

natural background or other sources, is a comparisonwithrisksfrom other activitiesor hazards encounteredinroutineexperience.Table II presentsa samplingof risksfor activitiesthat may resultin earlymortalityand annualrisks of death from accidents or natural phenomena.Becausenot all of the risks are directlycomparable,thevalues for mortality risks shown in Table I overlap therange of values for risks shown in Table II. The largestincremental risks from the exposure to the residual

contaminationare aboutthe samesizeas the incrementalriskof a 1000-mileautomobiletrip;mostare smallerthanthe annual risk of death fromlightning.

Some differencesin future conditionswillresult fromradioactivedecay processes.Whilethe total doses fromtransuranium elementswill rtoi change appreciably,thedosesfrom 90Srand 137CSwilldecrease50%in about 30years. At the GZ area the external radiation doses willdecreaseabout 90Y0in the same 30-yearperiod.

TABLE I

ESTIMATES OF RISK BASED ON EXPOSURES ATTRIBUTABLE TO RESIDUALCONTAMINATION IN AREAS OF FALLOUT FROM THE TRINITY TEST”

Locationb/Exrsosure

Hvtmtheticai Resident

GzInner fenceBetweenfences

White Sands Missile RangeBinghamChupadera MesaFar Fallout ZoneSan Antonio

Other H>potheticsdExposures

40h of \Vork in GZinner fenced area

Security PatrolsAnnual visitor at Open

House of Trinity Site

Natural Radiation Exposure,Los Alamos

l-year occupancy50-year occupancyRadiation ProtectionStandard

Incremental Risk

Increased Probability Basedon 50-Year Committed Dosesc

OverallCancer Bone Lung Liver

Mortality Cancer Cancer Cancer

2.0x 10-’ 2.2 x 10-~ 1.4 x 10-7 1.1x 10-61.1x 10-4 8.7 X 10-9 2.3 X 1O-s 4.2 X 1O-s1.9 x 10-6 6.3 X 1O-a 8.7 X 1O-s 1.0x 10-’4.0x 10-’ 5.7 x 10-8 4.2 X 10-8 7.5 x 10-s1.8 X 10-6 1.2 x 10-’ 1.6 X 10-’ 2.7 X 10-77.4 x 10-’ 4.8 X 1O-s 3.1 x 10-~ 3.6 X 1O-s2.2 x 10-7 6.0 X 10-’0 1.8 X 1O-s 1.5 x 10-9

9.6 X 10-’ ---9.0x 10-’ ---

—-.

——

1.2 x 10-~ ---

1.6 X 1O-s ---8.0 X 10+ ---

.. . ...

... —

———

—...—

Committed Dose

mrem in 50 yearsfrom l-Year Occupancy

ExternalWholeBody Body Bone Lung Liver——

1700 2.5 75 1.5 36880 0.17 2.9 0.26 1.414 1.8 21 0.97 3.41.7 1.6 19 0.47 2.5

13 2.1 39 1.8 9.05 1.2 16 0.34 1.21.7 0.1 0.2 0.2 0.05

8 .—

0.75 ---

— —.- —

1.0 — — —

134 . .— —6700 .. .— .- —

500 500 1500 1500 1500

‘All calculationsbasedon current conditions.bLocationsare describedin more detail in Cha~ter 4.“Probabilitiesare expressedin exponentialnotation;they can be convertedto expressionsof chancebytaking the numerical value in front of the multiplicationsign (x) as “chances”and writing a one (1)followedby the numbu of zerosgiven in the exponent.For example, 9.7 x 10-7 becomes9.7 chancesin10000000.

3

TABLE II

RISK COMPARISON DATA

IndividualIncreasedChance of DeathCausedby SelectedActivities

Increase in ChanceActivity of Death

Smoking1pack of cigarettes(cancer,heart disease)Drinking 1/2 literof wine(cirrhosisof the liver)Chest x-ray in good hospital(cancer)Traveling 10 milesby bicycle(accident)Traveling 1000milesby car (accident)Traveling 3000 milesbyjet (accident,cancer)Eating 10tablespoonsof peanut butter (livercancer)Eating 10charcoal broiledsteaks(cancer)

1.5 x 1O-s1 x 10-61 x 10-61 x 10-63 x 10-63.5 x 10-62 x 10-71 x 10-7

U.S. AverageIndividualRisk of Death in One YearDue to SelectedCauses

Cause Annual Risk of Death

Motor VehicleAccidentAccidentalFallFiresDrowningAir TravelElectrocutionLightningTornadoes

U.S. PopulationLifetimeCancer Risk

ContractingCancer from All CausesMortalityfrom Cancer

2.5 X 10-41 x 10-44 x 10-53 x 1O-s1 x 10-56 X 10-65 x 10-74 x 10-7

0.250.20

2. INTRODUCTION AND BACKGROUND

L THE DOE RESURVEYPROGRAM

The 1977 and 1983 survey of the Trinity Site wascarried out as part of the DOE program aimed atformulationof any remedialactionsfor Manhattan Engi-neer District (MED) or Atomic Energy Commission(AEC) sites.In the DOE program, tideswerereviewedtodetermine if residual radioactive contamination mightexist at the sites. If the radiological conditions wereuncertain,a surveyof the area influencedby the sitewasperformed.The filesand specialstudiesin existenceforthe Trinity Siteindicateda surveywouldbe necessarytoquantify the radiological condition of the 32-year-oldfallout area from the first nuclear explosionat WhiteSands MissileRange in New Mexico,July 16, 1945.

Severalstudiesof the falloutzone had beencarriedoutbeforethe resurvey.These includedsurveysimmediatelyafter the test in 1945,studiesby Universityof California,Los Angeles(UCLA) in 1948, 1950,and 1951.In 1973and 1974, the U.S. EnvironmentalProtection Agency(EPA) carriedout an extensivesoilsamplingprogramforplutoniumin the area. The study includedair samplerslocated on Chupadera Mesa and in Socorro, New Mex-ico. Starting in 1972 and continuing until 1979, LosAlamos Scientific Laboratory, conducted specialecologicalstudies of the movementof 137CSand pluto-nium isotopeson study plots on Chupadera Mesa andnear Ground Zero (GZ) locatedon White Sands MissileRange.Factors influencingthe surveywerethe historyofthe Trinity test, previousstudiesof the falloutzone,andthe stated objectives of the Formerly Utilized SitesRemedial Action Program. Each of these factors isdiscussed in more detail in following paragraphs.Separate chapters are devoted to the resurvey plan, theresults, and interpretation of the data. Appendixesareincludedthat contain the historicdata base, the raw datafrom this study, a log containing locations of samplelocations, calibration methods for the in situ detectorsystemused, and calculationalmethodsused for estima-tions of radiation dosefalloutradionuclides.

equivalentsfrom any residual

II. THE TRINITY TEST

The Trinitytest of the first atomicbombtook placeonJuly 16, 1945,on WhiteSands MissileRange in CentralNew Mexico.The test resultedin depositionand dispersalof radioactive fallout over a portion of central andnortheastern New Mexico. Figure 1 is a map of thegeneral area with Trinity Site marked on the lower left-hand corner of the map. The devicewas mounted on a100-foottower with cables for instrumentsand timingstrung to shelters9144m (10 000 yds) away. Figure2 isa photographofthe tower-mounteddevicebeforethe test.The Oscura Mountains are in the background of thephotographabout 5 mileseast of the test area.

Weatheron the day of the test started outbeingcloudyand windywith scattered showers,At 2:00 a.m., the testwas rescheduledfrom 4:00 a.m. to 5:30 a.m. At 4:00a.m., the rain stopped and at 4:45 a.m., a favorableweatherforecast indicatedthe 5:30 a.m. timewas accept-able.Weatherremainedcloudyafterthe test, as observedby planessent to drop sensorsduring and after the test.1After the test, a crater and zone of melted sand werecreated (Fig. 3). The green fused sand is referred to asTrinitite in many reports. The GZ area has been desig-nated a National Monument. As noted earlier, GZ islocated on White Sands Missile Range, and access iscontrolledthroughoutthe year. Once annually,the publicis invitedfor a controlledvisit to the site, usuallyin themonth of October. Figure 4 is a diagram of the GZfencedarea includedin the publicvisits.

III. THE TRINITY FALLOUT ZONE

Followingthe test, measurementsweremade to estab-lishthe trajectory of the falloutcloudand the depositionpattern overChupaderaMesa and areasnortheastofGZ.Measurementsduring 1945were made across the falloutpattern to outermostedgesof the falloutzone,

Figure 5 is a depiction of the fallout zone based onbeta-gammasurveysof the soilsurfacefollowingthe test.The falloutfolloweda northeasterlydirectionparalleling

5

6

the west of U.S. Highway 54 (Fig. 1).The cloudpassedover Chupadera Mesa, where localized areas of higherlevelswereobserved.

Another beta-gamma survey carried out in 1947and1948confirmedthe earlierobservationsand added detailto the mappingof the area,2Figure6 is an outlinemap ofthe contaminated area taken from the 1947 and 1948studies.2A primary transect reference line was estab-lishedin the 1947study.The transect of 34° 56’startedat the Section Marker at GZ. At every 4930 feet,referencepoints were marked for the first 11 points.At

point 12, the referencepoints were marked every 9000feet. From this primary transect, referenceline lateralswere extended 90° right and left. Samplingand studyareas were establishedaccordingto the lateral numbers.For example, an area of special study on ChupaderaMesaat lateral21 (about28 milesfromGZ) isreferredtoas area 21. This type of designation is referred to inreportsof severalstudiesof the Trinity falloutzone.

Since 1945,radioactivedecayhas resultedin substan-tial reductionsof the fallout levelsso that only the long-Iivedradionuclides90Sr,137CS,and 23gPuwith traces ofeuropium,remain. In the interveningyears, environmen-tal and biologicaltransport processes such as erosion,sedimentation,and bioticuptake have acted on the initialsurface depositionto redistributethese long-livedradio-nuclides. A number of studies were carried out tocharacterizethe radionuclidedistributionand redistribu-tion in the years followingthe test.

The first major studieswerecarried out between1947and 1950. These studies emphasizedradionuclidecon-centrations including plutonium for soils and plants,particularlyon Chupadera Mesa, the crater region,andthe region north of the crater, but still on White SandsMissileRange,314The studiesincludedcharacterizationinthe soilsand plantsof the area.

Plant studies includeda study of the revegetationofGZ. Studieswere also carried out that involveddescrip-tions of the movementof small mammals, reptiles,andbirds in the area surroundingGZ.S The results of thesestudieshavebeenincludedin considerationsof the designof this study.

In summary, elevatedlevelsof plutoniumand fissionproducts were measured in the fallout pattern, Themaximumconcentrationsin soiloutsidethe fencedareaof GZ were detectedon Chupadera Mesa about28 milesfrom GZ. The authors suggest a localizedrain showermay havescrubbeda portionofthe falloutcloud.4Duringthe study periodof 1947to 1950,therealsowas observedsomedownwardmigrationof fissionproducts in the soil.However, wind erosion in the crater area of GZ wasrelativelymore important than water in spreading thecontamination.cPlutoniumwas found in amounts up to19 pCi per square foot at area 21. No plutoniumwasfound in samplescollected3 milessouth of GZ.7 Studiesof plant invasion of the crater area through 1964 con-cluded that, while the area had not returned to climaxvegetation, distributional patterns were controlled bywater availability,soil conditions,and timingof climaticvariants rather than radiations

7

Fig. 3. Range qfter test.

In 1972, a series of special studies of the plutoniumdistributionwere started by Los AlamosScientificLabo-ratory. Soil, vegetation, and rodent samples along thefallouttransect were obtainedat GZ and out to 56.4 km(35 miles).’Soil samplesfrom GZ indicateda relativelyuniformvertical distributionof plutoniumin the 30-cm-deep soilsamples.Increasedmigrationof plutoniumintothe soil was observed. Concentrationsof plutoniuminvegetation and rodents were too low to make validcomparisons.From the data taken, four intensivestudyareas were establishedat 1.6 km, 16 km, and 44 km, inadditionto a controlsitesouth of GZ.1°About halfof theZJg,ZdOpuin the Trinity falloutzone soilswas found at the

5-to 20-cmdepth in 1973comparedwithtotal plutoniuminventoriesbeing detectedonly in the upper 5 cm of soilin previousstudies(21 to 25 years).PenetrationdepthsofZJg.ZqIJpu~to the fallout zone soils were related to thepresence of subsoil horizons containing carbonate ac-cumulationsand to the extent of rainwater penetration

into the soilprofdes.loillStudiesof plutoniumas relatedto concentrations on vegetation indicate concentrationratios as highas 1.0for dry weights.lzThe rangefor forbswas0.04 to 1.1and grasses0.05 to 1.2.Contaminationofplant surfaceswith soilparticlesis consideredthe causeof plant-soilratios higher than observed in greenhousestudies.

In 1973 and 1974, the EPA sampled and analyzedsoilsfrom across the regionof the TrinityfalloutfieldforZqgPuand 240pu in the top 5 cm Of the surface ‘Oil.13

Beforepublication,the resultsof the surveyand the fieldnotes from the samplingwere forwardedto Los Alamosby the EPA. The highest surface plutoniumlevel wasobserved on the White Sands MissileRange. The GZsamplecontained 1100nCi of 239,240pu per square meter

of soilsurface.A soilsampletaken approximately3.2km(2 miles) north of GZ contained 100 nCi per squaremeter, but neighboringsamplelocationsgave plutoniumvaluefactors of 4 to 10timeslower.

8

L1,,.5.!9s3

Ng. 4.

SWTM GATE

0 2CU ●m W ma “

0 00-s””

Swss

Diagramof IH.m”tyGZfences.

16T” / 166” 165”

‘5’J“’”””’mu’c’=v’‘ANTAm;

)/EoKlhUJ

\ WI L$ARO

#.VAUGHN

1

MOUN+AINAIR c~my?- U‘$ ●

GRAN QUIVIRAC$AUNCH

● m’ \

~40 wcORRo CYWUt~RASANANTONIO BINGdAM O—!! m = ~’mi~

t------ v-/ ti”lNITV

0-33

1 TEST ~ ●CARRIZOZO:WHIT’ SANDS IMISSILE !

Fig. 5. Thefalloutzonefmm the Tdnity test as&tamhed by a 1945 beta-gammasurvey.

Consistent with earlier findingsof the initial falloutdistribution, plutonium levels generally decrease withdistance from GZ and with lateral distance from thecenterline.The increaseon ChupaderaMes&some20 to30 miles from GZ, is also observed in the data. Thehighest level reported by EPA on the mesa at a singlelocation was 86 nCi per square meter. Backgroundvalues,that is, the minimumvalues,werereported at lessthan 1 nCi per squaremeter.

The EPA studyalsoincludedcarryingout air samplingfor airborne plutonium. An air-sampling station wasestablished at Socorro, New Mexico, and another air-samplingstationwas establishedat MontePuerto Ranchon Chupadera Mesa. Air sampleswere collectedover a10-month period. The samples were analyzed for239,240$23apwThe SOCOrrO station acted as a control areabecause it was locatedout of the falloutzone.The 236Puresultsfrom both locationswerebelowthe detectionlevel

9

.

IV. THE RESURVEYOBJECTIVESCLAUNCH ●ROLLIN:N~LAINS

( 22+

PRIMARY TRAt6ECT

/

TO SAN ANTC+JIO

TO CARRIZOZO‘. . U.S. HWY. 3S0

SECONOARY TRANSECTREFERENCE LINE

Fig. 6. Outlinemap of the contaminatedarea asdeterminedby 1947 and 1948 survey.A transectwas establishedwithnumberedlaterals.

on many of the samples.Often, the results for ‘9’240Pualso were below detection limits, and only the datapertainingto the detectedplutoniumwere reported.Theprimary resultsof the air samplingindicatedthat the airconcentrationswere wellbelow the proposedEPA limitfor transuranicsdepositedon soils.The conclusionof thestudy indicatedthat, whilehigherplutoniumlevelscouldbe found at very localizedindividualsites,the samplingdensityused in the study on Chupadera Mesa makes itunlikelythat grosslyhigherlevelsare presentin the areaexceedingthe EPA proposedguidance.

Becausethe EPA study limiteditself to plutonium,itwas decided that the 1977 resurvey of the fallout zonewould include fission product and activation productmeasurements in addition to confirmatory plutoniummeasurements. Data for the resurvey concentrated inareas in the far faUoutzone (the area north of WhiteSands Missile Range, and in particular, ChupaderaMesa) because,at the time, it was felt this was the mostimportantarea.

As previouslymentioned,a number of studies havetaken special views of either the early distributionoffissionproducts, or later, the distributionof plutonium.The specialLos Alamosecologystudiesconcentratedonintensivestudiesof four relativelysmallareas, 1hectarein size.The EPA study concentratedon the characteriza-tion of plutoniummainly in the Chupadera Mesa area.These data are included in the data base of this study(AppendixA). The objectiveof this study,however,wastwofold.The firstobjective,that of theresurveyprogram,was to designa samplingprogram that would allowtheestimationof radiologicaldoseto peoplelivingin the areafor current land uses. These land uses are for grazingcattle and smallhome gardens.It is anticipatedthat GZand the WhiteSandsMissileRangewillremainincontrolof the U.S.Army. Second,becausea data baseexistedfora numberof years and it is knownfromthe earlierstudiesthat wind and water playeda major role in redistributionof the fallout material, it was decided that the studywould also make special measurementsto investigateredistributionof the materials from the actions of windand rain. Because high-resolutiongermanium lithium-drifted [Ge(Li)] gamma detectors now exist, and areusable under field situations, it was decided to use theLawrenceLivermoreLaboratorymobileradiationdetect-ion system.Use of the germaniumdetector with a pulseheightanalyzerin a mobileunitenabledthemeasurementof the distributionof fissionproducts in soil in a rapidmanner.

Redistributionof the surfacedeposited fissionprod-ucts and plutonium was an important considerationof the studiescarriedout duringthe UCLA seriesin 1947to 1951.A strong redistributionof surface soil by bothwindand rain was observed.Flash floodsdo occur in thearea and tend to move soils and sediments in runoffchannelsin largequantities.Pointsof depositionfor thesesediments that are moved by heavy water eventa areusually low points that are often dug out to collectthewater for livestock watering. Therefore, the study in-cluded a number of measurements where the 137CScontent was measured both upslope and at the finaldepositionpoint for redistributionof the fissionproductsand probablyof plutoniumalso.

To evaluatethe significanceof the residualcontamina-tion at the GZ location, a series of core samples wastaken in 1983.

10

3. METHODS AND APPROACH

This study was designedto supplementexistingdata on the distributionof falloutfromthe TrinityTestto allowestimationof potentialradiationdosesbased on land use.The samplingprogramtook advantageof previousstudiesof the falloutarea, as weUas specialstudiesof smallareas of the falloutzone.

I. APPROACH

Previous surveys had determined the extent of thefalloutarea and generalconcentrationsof surfacedepo-sition of fallout.Later studiesby Los Alamos NationalLaboratory concentrated on the mechanisms for re-distribution of the fallout in several intensive study~eas 14 In the case of the U.S.EnvironmentalprOteCtiOIl

Agency studies,the principal investigatorprovidedfieldnotes so samplelocationscould be relocated for furthersampling.

The samplingprograms were carried out during twotime periods. In 1977 the far fallout zone, ChupaderaMesa, and areas around GZ on White Sands MissileRange were sampled.Because time and resourceswerelimited,maximumuse of previoussurvey resultsguidedthe plan for characterization of the residual falloutradionuclides.Also, the loan of a van with instrumenta-tion and personnel from Lawrence LivermoreNationalLaboratory allowed use of real-timedata for decisionsaboutmeasurementlocationsin the field.In 1983a set ofmeasurementsand sampleswas taken at GZ. Analysisofthe 1977survey data had indicatedmore detailedinfor-mation on the depth distributionof radionuclidesat GZwouldbe necessaryfor engineeringstudiesof the area. Inboth surveys, in situ measurementswith a germaniumlithium-activated [Ge(Li)] high-resolution gamma-rayspectrometerand specialsamplingmethodswereused toobtain informationon the concentrationsand locationofradionuclides.

IL METHODS

A. In Situ Measurement

In planningthe Trinitysurveyeffort,it was determinedthat the utilizationof in situ Ge(Li) spectrometrywould

provide a number of advantages over sole reliance ontraditional soil-samplingtechniquesfor obtainingan in-ventory of radionuclidesin the soils of a very largeTrinity fallout field. The followingconsiderationsweretaken into account.

(a) The relatively short counting time required toobtain a satisfactorygamma spectrumfor a sam-ple (30 rnin compared with 1000-2000min in thelaboratory for a 100-gsoilsample)allowsa poten-tially larger number of sample locations to beexamined.Alternatively,it allows the reallocationof laboratoryG~Li) analysistimeto the necessarysoil profde concentration determinationsin sup-port of the in situmeasurements.

(b) Local inhomogeneitiesin soilradionuclideconcen-tration (both in depth and in small regions) areautomatically averaged because the detector isrespondingto photons from a very large quantityof soil (several metric tons compared with a fewhundred grams in a laboratory system).

(c) Combining the inherently high resolution of aGe(Li)spectrometersystemwitha mobiledetectorand support systempermitsimmediatefeedbackinthe field of both radioisotopeidentityand relativeactivity(cpm),whichallowson-sitedecisionsto bemade concerning what additional or differentmeasurementsmightbe neededand where.

The methodologyand instrumentationfor and feasibil-ity of utilizingin situ Ge(Li)spectroscopyfor identifyingand quantifying radionuclidesdistributed in soil havebeen investigatedand successfullydemonstratedat sev-eral laboratoriesover the past severalyears.ls-lgFor theTrinity resurvey,equipmentand techniquesdevelopedbythe Lawrence Livermore National Laboratory (LLNL)were utilized through a cooperative arrangement. Anoverviewof the system and its calibration are found inpublishedreports.17

11

The response of a closed-end,cylindricalGe(Li) de-tector,placed at a fixedheight(1 meter)abovethe soil,isan energydependentfunctionof the angular responseofthe detector and the fluxof unscatteredphotonsincidenton the detector per unit of soil radioactivity.Normally,calibrationof this responseinvolveslaboratory measure-ments and calculationalprocedures independentof thegeometriesof the distributed sources to be evaluated.Radionuclidesthat have been redistributedthrough theverticalsoilprofdefrom an initialsurfacedeposition(forexample,fallout)are usuallyassumedto be exponentiallydistributed in this calibration calculation. As acrosscheck of the laboratory calibration and the suit-ability of the exponentialdistribution assumptio~ anempiricalcalibrationfactor for 137CSwas derivedas well.

Althoughdetector response to a source does dependon suchvariablesas the massattenuationcoefficientsanddensitiesof soiland air under fieldconditions,the crucialvariableis the specificationof the relaxationdepth of theactivitybeingmeasured(that is, the inverseof the powerof the exponentialdistributionfunction).Under certaincircumstancesthis parameter can be readilyand reliablyestimated, as in the case of fresh fallout of short-livedradionuclides(’Be, for instance)or the case of naturallyoccurring radionuclidessuch as uranium, which tend tobe uniformlydistributed in soil. But the case of aged,long-livedfallout radionuclidesdeposited over as largeand varied terrain as is found in the Trinity falloutfieldpresents a more diflicultconditionto interpret.Concen-tration profilesfor 137CSwere determinedat reasonablyrepresentativelocationsthroughoutthe fieldby the tech-niqueof soilsamplingand laboratoryGe(Li)analysis.Asmightbe expecte~ thesedistributionsreflectin a complexway the effects of the wide differencesin rainfall inpu~soil properties and depth, and vegetationtype and den-sity, which occur over the range of low-elevation,drydesert terrain, through the grass and piiion-juniperhabitat of the mesas, to the coniferforestsof the moun-tain slopes. Representative values were selected andassignedby judgment to each samplelocation.An effortto developa linear box modelof redistributionof 137CSfollowingdepositionwas made, but the many uncertain-tiesin estimatingthe relevantparametersin the modelledto results judged to be of no more value than makingassignments on the basis of proximity to measuredprofdes,similarityof soil type,vegetation,elevation,andso forth.

B. Samplingand Analysis

Samplingof soils, sediments,and vegetationaccom-paniedmost insitu measurementsthroughoutthe surveyarea. Of particular importancewere soilprofilesamplestaken at the location of the in situ measurement.Thesesoil protile samples were used to develop a correctionfactor for calibration of the Ge(Li) detector system toaccountfor the depthdistributionof gamma-rayemittingradionuclides.

The methods used for obtaining samples and subse-quent analysisconsideredthe sensitivityof the systemsused and the survey design.At locationswith changingtopographical features, additional soil samples weretaken to study plutonium and strontium distribution.These isotopesare not present in sufllcientquantity fordetectionby the in situmeasurementsystemused.

Soil samples were obtained using a 12.8-cm-(5-in.-)diameter ring that was pushed or pounded 5 cm (2 in.)into the soil.Soilwas removedfrom around the ring byuse of a shoveland hand trowel.An aluminumsheetwaspushed under the ring and both soil and ring were liftedout.The soilwas collectedin plasticbagslabeledwiththelocationidentificationand an indicationof the depth andsoil horizon sampled. The procedure was repeated foreach soil proftie sample, taking care to avoid crosscontamination. At each in situ measurement location,three 5-cmdeep soilprofdesor a total of 15-cm-(6-in.-)deepsampleswereobtained.At selectedlocations,profdedepthsto 40 cm (16 in.)weresampled,

Vegetationsampleswere collectedusing grass shearsto cut the grass or weeds within 1 to 5 cm of the soilsurface.For trees,new growthand the last year’sgrowthwere collected.Sampleswere placed in plasticbags withnotationof the plant speciesand the identificationnum-ber for that location.Notes were made on the vegetativecover, measured slope, and soil characteristics.Topo-graphicfeaturesof the surroundingarea alsowerenoted.Additional vegetation samples were collected for laterverificationof speciestypes.

Soiland vegetationsampleswere transporteddaily tolaboratories at New Mexico Institute of Mining andTechnology in Socorro, New Mexico. Samples wereplacedin dryingracks of windowscreenon woodframesin an unused greenhouse.After initial air drying, heatlamps were used to dry the samplesto constant weight.Constant weightwas attained in 1 hour under the heat

12

lamps.A dryingtimeof 2 hours for both soilsand plantswas used as routinepractice. After they were dried, soiland plant samples were pulverizedusing Waring Blen-ders. Vegetation samples were packed into cans byoverfiiingabove the top of the container.A manualcansealercompressedthe samplewhilethe lid was fastenedto the can. About 80 g of dried vegetationwas sealedinthe can for later countingon a laboratoryGe(Li)detectorsystem.At the sametime, 10.05g of samplewas weighedinto a plastic sample bottle and labeledfor transport toLos Alamos National Laboratory, where radiochemicalanalyses were conducted. Soil samples werehomogenizedand about 360 g ftied the cans. Samplesof10.05g of each soil or sedimentsamplewere placed insmall plastic bottles and labeled for transport to LosAlamosNationalLaboratory radiochemicallaboratories.

Because the soils were anticipated to contain greaterquantities of radionuclidesthan vegetation, a separate

laboratory was used for soilhandling.Samplesfrom theGZ area were hancikl with specialprecautionsbecauseof higherradionuclidecontents.Speciallaboratoryclean-ing before and after handling these segregatedsamplesminimizedcross-contaminationpotential.

Vegetationand soilsampleswerecountedon a Ge(Li)system at New Mexico Institute of Mining and Tech-nology as an initial screening method for radionuclideidentification.Final analysisof the samplesfor gamma-emitting radionuclideswas conducted by LLNL withcalibratedlaboratory Ge(Li)systemsand data reductionaccomplishedusingcomputercodes.zo

Vegetationand soil samples sent to the Los Alamosenvironmental surveillanceradiochemistry laboratorieswere analyzed for 238Pu,2391240Pu,and 90Sr.21Plutoniumanalysesused standard digestion,anion exchange,plat-ing,and alpha spectroscopymethods.Strontium-90anal-ysesutilizedstandard ‘OYingrowthmethods.

4. RESULTS

I. TOTAL AREA

For an overviewof the amount of radioactivefalloutfrom the Trinity Test the data have been reviewedforoverallmeasurementof 137Cs,2391240Pu,and other radio-nuclides.Figure 7 is a generalmap of the Trinity falloutarea. Data points are designatedas small squares.Thesolid lines divide the data base into areas of generalinterestfor assessmentof the radionuclideson morearea-specific bases. The data base was divided into areasdesignated:Trinity GZ, San Antonio,White Sands Mis-sileRange, Bingham,Chupadera Mes4 and Far FalloutZone. SectionII of the Resultspresentsthe mean data byarea. Appendix A lists the data from all data basessummarizedin the Resultssectionof this report.

A. Trinity Data Analysis:137CSin Soil

There are three independentmodesof measurementofradionuclidecontent in Trinity soils used: (1) direct, insitu gamma spectroscopy,(2) laboratory gamma spec-troscopy of canned soil samples, and (3) laboratoryradiochemicalanalysisof soilsamples.(SeeChapter 2 ofthis report for details.)There is only limitedoverlap ofdetermination of specific radionuclides by these ap-proaches. In the case of 137c5, o~y in situ spectroscopy

and laboratory spectroscopy of canned samples wereapplied;one providinginventoryestimatesand the othersoilconcentrationdata. In application,these two sourcesof ~formation on U7CSinventow are not totally inde-pendent.The in situ measurementrequiresknowledgeof

.~~1SAROSA

FAR FALLOUTZONE

.ENCINO

WlmRD.

MOUN INAIR VAUGHN.

.“...

-.. . .

. ● .: CORONA. . . . .

CHUPADERA MESA. . .: CLAUNW.a.;

SANANTtlNIO .

BINCHAM.e&Y’ /r

~m III RIO ( 1CRANDE. / o 10 20 30 40 50I \/ ISANDS ‘..4...” ”.. “ . %1 /1, ,,!1

Fig. 7. Generalmap of the Trinityfallout area and themeasurementlocations.

14

. . ...—-— — - — -—

the verticaldistributionpattern in the soilsin the vicinityof the detectorin order to be translatedinto an inventoryestimate.The soilsamplingresultscan be usedto providethis needed distribution estimate. A discussion of thereduction of these data to provide 137Csinventoryesti-mates follows.

Soil samples were collected at a large number oflocationsthroughout the survey area at locationswhereinsitu spectroscopymeasurementsweremade(butnot atevery such location).Usually sampleswere collectedatthree consecutive5-cm depth intervals.However,whenthese samples were processed, not all samples wereprepared and counted. Profdes for which complete ornearlycompleteIWCSconcentrationdata existare shownin Table III.

An estimatecan be made of the *37CSconcentrationinthosesamplesthat werecounted,but for whichno cesiumdata were reported based on the minimum detectableactivity (MDA). Using the MDA estimate in thoseinstanceswhere a samplewas countedbut no 137CSdatawerereportedprovidesan upper-boundestimateofinven-tory. One approach to estimatingthe MDA for *37CSis toexaminethe trend in uncertaintyin the reporteddata.TheMDA can be taken to be the smallestamountof activitythat would likely be reported with an error not greaterthan some acceptablelimit,say 33%. At an uncertaintyof 33Y0,the corresponding concentration is approx-imately0.1 pCi/g. Another approach based on statisticalconsiderations,described in Appendix E, yields similarestimates.

Replacing MDA everywhereby the estimate of 0.1pCi/g substantially increases the number of profdeestimates.The profdecharacterizationis by meansof anexponentialfittingfunction:

C = COexp(-ax) (1)

whereC is the concentrationat depthx, COis the surfaceconcentration,and a is the inverserelaxationdepthof thedistribution.This relationcan bejustifiedtheoreticallyonthe basisof a simplebox modelin which””thesoilprofdeischaracterized by a sequence of boxes that exchangecontaminantsover a period of time at a certain flowrate(A. T. .lakubide,MigrationofPlutoniuminNaturalSoil,1977).To incorporatethe uncertaintiesin the concentra-tion determinationsinto the profilecharacterization(thatis, into the determinationof the inverserelaxationdepthestimate), a logarithmic transformation of Eq. (1) ismade and the methodof linearleast squaresappliedwith

some modification to compensate for the fact that,unadjusted, the least-squaresestimate underemphasizesthe uncertaintiesfor smallvaluesof C. (SeeAppendixC,least-squaresfittingof an exponentialfunction.)

The resultingalphaestimatesfor the ChupaderaMesaare shown in Table IV and GZ samples in Table V.Evidently, the mesa samples are characterized by ashallowerprofde (largealpha), and showlessvariabilitythan the GZ samples do. This reflects, perhaps, themechanicaldisturbanceof GZ soilsbut also differencesin the originaldepositionprocessesover these two areas,the geochemistryof the respectivesoils,and other envi-ronmental factors such as precipitationfrequency, in-tensity,and so forth.

An estimateof the inventoryof 137c5 (nci/m2) in ‘iese

soils can be made utilizingthe concentrationand profiledata. Sincethere can be expectedconsiderablemixinginthe topmostlayerof soil,the averageconcentrationat themidpoint in the O-to 5-cm intervalwill be taken to berepresentativeof the O-to 2.5-cmintervalas well.(Thisestimationshouldtend to overestimatethe actual inven-tory because there is most likelya parabolicdistributionshape in the near surface layers caused from depletionprocesses at the surface.) Then the estimate of theinventory in the O- to 2.5-cm interval is given, for adensityof 1.5gfcm3,by

IZ.5= & (@/g) x 2.5 cm x 1.5(~cm3)

x 104(cm2/m2)x 103(nCi/pCi)= 37.5 CZ.S. (2)

Then the total inventorycan be estimatedoverthe rest ofthe profdeassumingthe fittedexponentialdistribution:

I2.5–00

‘3705c’’+(l:e-x‘x)(105)@0)(c’J=(37.5 +:) C2.,*J$+$ , (3,

wherethe integralis approximatedby one-half.A comparisonof the in situ inventoryestimateswith

many of the soilsampleestimatesispossibleand providessome measure of the compatibility of these two ap-proaches to inventoryestimation (TableVI).T3e%aukeofdelays in processingof canned soil samples,assignmentof the a profdeparameter for each samplelocationhad to

)5I

TABLE III

137c8 SOIL cONCENTRATION DATA

Location

GZ orMesa

GGGGGGGGGGGMMMMGMMMMMMMMMGMMMMM

LADB’No.

Concentration (pCi/g)

O-5cm FSDb - -- ‘-–5-10cm FSD 10-15cm FSD

1990199119881989200620052012201620182014201920272026204520481987205320502057204921152116211820812080199221202071205820282059

13.66.040.611.750.350.770.380.820.260.990.543.195.421.181.081.870.710.792.560.832.955.422.061.290.320.101.753.125.145.871.04

0.0110.0360.4860.1220.1880.0310.2270.0320.1730.0330.0570.0170.0630.0340.0470.110.0560.0250.0170.0520.0270.0130.030.0320.0810.3440.0300.020.010.010.04

——.——.

aLADB- Los AlamosData Base.bFSD- Fraction~ Standard Deviation.c-- meansno data taken.dMDA. MinimumDetectableActivity.

21.79.26

24.950.170.280.520.410.260.26

.-0.380.120.480.220.130.16

----—--—

0.090,480.10

-—--

0.181.0

-----

0.18—

0.0130.0140.0240.1790.1850.0320.1270.240.058

—0.1080.1350.0970.0850.2740.291

--——--

0.1920.0970.162

——

0.2820.040

——

0.29—

6.98c--

-.

MDAd--—

MDA0.110.150.970.140.21

MDA0.080.19

MDA0.060.28

MDAMDAMDAMDAMDAMDA

0.11—

MDA0.140.08

MDAMDA

0.036--—-——.-

MDA0.1640.3550.0590.2990.155

MDA0,2240.296

MDA0.2040.221

MDAMDAMDAMDAMDAMDA

0.163--

MDA0.350.34

MDAMDA

16

I

LADB’No.

20262027202820452048204920502053205720582059207120802081211521162118

TABLE IV

CHUPADERA MESA 137C!SPROFILE DATA

cCone at2.5 cm(m/g) FSD (B)b

5.423.195.871.181.080.830.790.712.565.141.046.870.320.292.955.422.06

——..

0,0130.0170.0100.0340.0470.0520.0250.0560.0170.0100.0400.0200.0810.0320.0270.0130.030

.——

a(cm-’)

0.330.330.530.320.220.220.100.250.330.420.240.390.110.270.490.480.47

Note: Mean a = 0.3235 and u = 0.1281.

‘LADB - Los AlamosData Base.bFSD_FractionalStandard Deviation.

be made on the basis of limitedinformation.Thus, thereare a number of signitlcant differences between theassumeda for in situ estimationand the fitteda for soilsampleestimation(TableVII).However,correctedinsituestimates of inventorybased on detectorefficienciesas afunction of a (Chapter II) were made correspondingtofitteda’s and are shownin column5 of Table VII.

Figure8, a plot of soil-samplegamma insituinventoryestimates, suggests that the two estimation proceduresyield similar results. A paired t-test was calculated forboth corrected and uncorrected data (excludingsample2014,whichis a GZ sample),with the resultthat the two

FSD (a)

0.640.090.160.100.290.500.400.320.330.290.450.230.480.410.170.060.16

Sequence

0.40.20.40.20.40.20.20.20.40.40.40.40.20.40.70.70.7

samplemeans are not sigai!icantlydifferentat the 90Y0confidencelimit in either the corrected or uncorrectedcases. The a parameter correction appears to make onlya smallditTerencein comparability.Possiblythe fact thatthe in situ technique is averaging over a considerablylarger volumeof soil at each samplinglocation than thecorrespondingsoil samples is a compensatingeffect tothe uncertaintiesin estimatinga.

Thus, it would appear that the in situ 137CStotalinventory estimates are comparable with soil samplingestimateswith an uncertaintyon the order of 50940.

17

TABLE V

GROUND ZERO TO CHUPADERA137(=s PROFILE DATA

LADB1No.

1987198819891990199119922005200620122014201620182019

Cone at

2.5 cm(Pa@

1.870.611.75

13.606.040.100.770.350.380.990.820.260.54

FSD (C)b

0.110.4860.1220.0110.0360.3440.0310.1880.2270.0330.0320.1730.057

——

a (cm-l)

0.370.120.40O.(K0.080.120.080.040.030.0020.210.020.08

‘LADB - Los AlamoaData Base.bFSD. Fraction~ standard Detiati.

B. Trinity Data Analysis:239’- in Sod

MESA

FSD (a)

0.240.17om0.010.042.170.142.122.510.0060.214,27Q.43

Direct determinationof the concentrationand inven-tory of plutoniumin Trinity soilswas carried out by soilsampling and radiochemical anaiysea. Preliminary in-vestigationof the possibilityof utilizingthedetermin*of ‘lAm inventoryas an indirectmeans of detcrmiaing239,240pu ~ventory prov~ UnSUc~SSfd~ M m

observedvery low concentrationof 241Amin the Trinitysoils,even in the vicinityof GZ.

The soil radiochemicairesults are tabulated in TabieVIII. These data indicate a fairly rapid dccrcast inplutoniumconcentrationwith d~’th in most cases. Butthere are some significantexceptionssuch as at samplelocation 2072, which is a fla~ grassy sedimenttrap onChupadera Mesa Here, relativelyhigh concentrations(>1 pCi/g) persist ~ a depth of 10 to 15 cm. ~Pdistributionof plutoniummight be ex~ to occur insuchsedimenttraps; however,no symtcmatE. attcmptwas

TABLE VI

137cS INVENT(jRy ESTIMATES

A. Chupadera Mesa

l-cmLADB’ Inventory

No. (nCi/m2) FSD

202620272028204520482049 .20502053205720582059207120802081211521162118

81.347.8588.0517.7016.2012.4511.85iO.6538.4

177.115.6

103.054.89

19.3544.2581.3030.90

0.0130.0170.0100.0340.0470.0520.0250.0560.0170.010.040.020.0810.0320.0270.0130.030

B.GZ to Chupadera Mesa

1987198819891990199119922005200620122014201620182019

28.059.15

26.25204.0

90.61.5

11.555.255.70

i4.8512.303.908.10

0.110.490.120.010.0360.3440.0310.1880.2270.0330.0320.1730.057

TotaiInventory(nCi/m2)

449.6264.6386.399.56

114.187.7

148.169.2

212.4376.3104,0521.9

55.6120.0200.9372.6142.9

145.999.1

131.253710.01359.0

16.25173.25144.4204.3

7462.189.32

204.75121.5

“LADB- M AlamosData Base.bFSD. FractiOn~ Standard Deviation.

FSDb

0.640.090.180.110.290.500.400.320.330.390.450.230.480.410.170.060.16

0.260.510.200.010.052.170.143.10.230.030.214.20.43

18

TABLE VII

COMPARISON OF IN SITU AND SOIL SAMPLE ESTIMATES OF 137Cs TOTAL INVENTORY (nCi/m2)

Inventory Inventory Inventory LADBa Assumed In Situ Correctedb Soil Sample Measured

2012 2014 2016 2018 2019 2026 202 7 2049 2050 2053 205 7 2058 205 9 207 1 2080 208 1 2115 2116 2118

0.2 0.03 0.20 0.20 0.20 0.40 0.20 0.20 0.20 0.20 0.40 0.40 0.40 0.40 0.20 0.40 0.70 0.70 0.70

236.6 858.2 84.58 90.92 26.43

540.0 3 14.0 139.6 125.2 189.0 158.7 323.4 21 1.3 388.7 81.5

135.5 83.7 84.4

100.0

5.73 25.29 4.46 2.96 1.19

49.28 4.74 3.53 3.43 4.01 3.04 4.22 3.40 5.35 2.9 1 2.74 2.12 2.23 2.23

701.3 1501.9

84.6 269.5

99.7 597.9 23 2.7 139.6 185.6 189.0 175.7 323.4 284.8 388.7 120.8 168.0 98.3 98.7

120.9

204.3 7462.1

89.3 204.8 121.5 449.6 264.6 87.7

148.1 69.2

212.4 376.3 104.0 52 1.9 55.6

120.0 200.9 372.6 142.9

0.23 0.03 0.03 0.002 0.21 0.21 0.17 0.02 0.10 0.08 0.64 0.33 0.09 0.33 0.50 0.22 0.40 0.10 0.32 0.25 0.33 0.33 0.29 0.42 0.45 -0.24 0.23 0.39 0.48 0.11 0.41 0.27 0.17 0.49 0.06 0.48 0.16 0.47

aLADB - Los Alamos Data Base. bThe number of counts in the 137Cs photopeak is converted to nCi/m2 by a detector efficiency term

cT S D - Fractional Standard Deviation.

made to fully explore the extent of vertical redistribution of plutonium in soils.

As in the case of 137Cs soil concentrations profile data, these plutonium data can be fitted by an exponential distribution model in most cases to provide an estimate of distribution with depth, and thereby, inventory. Least- squares fitting of these data (where possible) with an exponential fitting function yield the results tabulated in Table IX.

These profile characterizations clearly point to the highly variable or indeterminate distribution conditions of

the GZ area due possibly to mechanical disturbance in the characteristics of the fallout materials, and so forth. The fit of the shapes of the concentration depth profiles to an exponential function is reasonably good on Chupadera Mesa; but there are some notable exceptions. Some of the cases where there is considerable uncertainty in the profile parameter a are probably attributable to very low concentrations, especially at greatest depth, with consequent poor recovery and counting statistics. Others (sample 2080, for example) may reflect other processes at

19

Fig. 8. Comparison of in situ and soil sample estimates of total 137Cs inventory.

IN-SITU

work affecting vertical redistribution rather than infiltra- tion, such as disturbances by burrowing rodents, cattle, or big game animals.

Concentrations of 238Pu in these soils are so low as to make reliable estimates of profile distributions, and con- sequently total inventory, impossible. Table X illustrates the order of magnitude of some surface (0- to 5-cm) concentrations and corresponding 238Pu/239Pu ratios. There is apparently about 20 times more 239Pu than

238Pu in the surface soils, independent of location.

The 239,240Pu inventory estimate was made utilizing the same strategy as was used for 137Cs inventory estimates, that is, by assuming an essentially uniform concentration in the 0- to 2.5cm layer, and a decreasing exponential distribution over the remainder of the profile. On these assumptions, the 0- to 1-cm inventory I, (most readily available for resuspension) and the total inventory I, estimates are given, assuming again a density of 1.5 g/cm3,

These two inventories are tabulated in Table XI for those cases where adequate data exist. Samples for which either the profile estimate could not be made or for which the uncertainty in the surface concentration and/or profile a estimates were too great to provide useful total inventory estimates, still have a surface inventory esti- mate listed. Evidently in the case of GZ environs samples, only the near surface inventory estimate is usable.

C. Other Fission and Activation Products in Soils

In addition to cesium and plutonium, several fission products and activation products from the Trinity event and more recent Chinese nuclear tests were detected by the Ge(Li) systems used. The activation and fission products from the relatively recent fallout were detectable at most locations by observing the 95Zr and 95Nb gamma rays in the in situ spectra. The average 95Zr (half-life, 64 d)22 areal concentration for the approximately 2500 mi

2

surveyed was 2.4 ± 0.12 nCi/m2 and the 95Nb (half-life, 35.1 d)22 average concentration was 3.8 ± 0.15 nCi/m2. The range of concentrations was from undetectable to 6.6 nCi/m2 for 95Nb. Of the 116 measurement locations for 137Cs, 95Zr was detected at 88 locations and 95Nb at 92 locations.

Other short-lived radionuclides detected by the in situ Ge(Li) system were 7Be and 103Ru. The relatively short half-lives of 53.4 d22 for 7Be and 39.3 d22 for 103Ru also identify these radionuclides as being part of fallout from the 4-megaton Chinese nuclear test on November 17, 1976.7 The 7Be concentration on an areal basis averaged 8.1 ± 0.7 nCi/m2 with a range from undetected to 26 nCi/m2. Of the 116 locations monitored for 137Cs, 62 locations had detectable 7Be. Only 22 out of the 1 16 locations contained detectable lo3Ru with concentrations for the area surveyed averaging 0.2 1 ± 0.04 nCi/m2. The range was from undetectable quantities to 1.9 nCi/m2.

The in situ gamma spectra and laboratory analyses of soil indicated the presence of the activation and fission products 6oCo, 152Eu , and 155Eu. Because of the longer half-lives associated with these radionuclides, the quan- tities present are considered to be from the Trinity test. The half-life of 6oCo is 5.27 yr; 15'Eu, 14 yr; and 155Eu, 5 yr.22 The areal concentration of these radionuclides at two GZ locations as measured by in situ methods indicated 5000 nCi/m2 and 50 nCi/m2 of 60Co and 1.1 x 104 nCi/m2 and 1.2 x 103 nCi/m2 of 155Eu. For areas

20

TABLE VIII

TRINITY SOIL CONCENTRATION OF 2]902%

locationActivity (pCi/g)

LADB’ GZ orNo. Mesa (Ml 0-5 cm FSDb 5-10cm FSD 10-15cm FSD

1998

2001

2003

2009

20142016201820262027202820372047

2052’20482049205720592060206520712072207320762080208220842096209721152118211921202121

GZGZGZGZM

GZGZM

MMMMM

M

M

M

MMMMMM

M

M

MMM

MMMMMM

24.3

64.9

3.8

0.48

0.1650.1220.673.511.714.071.83

0.980.122

0.3980.246

0.701.21

1.06

0.2711.544.586.700.4350.0270.951.23

0.2130.61

0.250.180.170.230.69

0.02

0.02

0.05

0.04

0.050.080.040.030.030.040.030.040.070.0580.040.030.06

0.040.04

0.030.030.030.030.150.040.040.06

0.050.160.070.060.13

0.04

57.444.40.050.450.71

...

-mold0.1180.2040.1090.0820.2410.0040.019

.-

0.3830.0330.3020.002

—

3.88...

0.0180.0240.0100.0560.0020.1530.0210.013

-0.010.600.51

0.02

0.020.80

0.04

0.03—.

2.00.070.050.060.06

0.060.750.168

-.

0.05

0.15

0.04

0.71.-

0.03—.

0.170.170.200.111.50

0.040.190.232.00.05

0.04

0.15

201

-0.06

0.47

0.146-0.68—

0.0180.0740.007

—

0.1720.010

0.00590.001

0.010.018

0.157

4.001

0.0611.15

—

0.0160.016

-0.OQI0.009

-0.0030.0070.00130.0010.005

0.037—

“LADB - l-m Alcmm Data Base%SD is tie ztcndcrddeviationofthc mccmrcd vcluedividedby tie mcazurcdvalue.%Iulksilrdicltctht scrrrplewcc nc4taken w not cndyzcd.

0.470.010.670.040.860.04

—

0.220.080.28

--

0.050.00010.321.55Omol0.170.081.290.100.03

.-

0.090.191.00.441.00.431.154.01.00.14

.-

15-20cm

-. c-.——-.—.—.-.—-.-.0.0130.0017

——

—

—

0.088—

-.—-.-.-.—-.

—-.—-.—-.

-.

FSD

-.——-.—...—-.-.——0.2310.71

——.—.—

0.10———...—.——..-———————

20.25cm

...-.-.-.-....-.-.—.--

0.007-....

0.002——.

0.053—.-.-.....--.—...-.

0.002-.-.-.-....

FSD

—..—...-.—.-.—-.-.-.—0.29

-.-.

1.50-.

-.

0.01—

-.-.—....-.-.-.

-.

0.94......

-.-...

‘Additional profdcs:25.3o cm, 0.007 (1.8) pCi/g; 3CL35cm O.&323(0.61) pCi/g; 40-45cm, 0.0075 (0.25) pCi/gT4cgativevcluecrcprcscntobservationssmallerthzn chemicalblcnk vclues.

21

TABLE IX TABLE X

GZ ENVIRONS ANDCHUPADERA MESA ‘9’240puSOIL

CONCENTRATION PROFILE ESTIMATES

Surface SoilConcentration

C = Cone Inverse Relaxation

LADB’No.

199519982001200320092016201820262027202820372047204820492052205720592060206520712072207320762080“208220842096209721152118211921202121

at 2.5 cm Depth of Profile@C~g) FSD (C)b a(cm-’) FSD (a)’

(uniformlyuncontaminatedat background)(a indeterminate-disturbed soil at GZ)(a positive—disturbedsoilGZ)3.8 0.05 0.86 16.50.48 0.04 0.001 12.9(a positive-disturbed soil)

(a indeterminate–surface depositonly)3.51 0.03 0.67 0.061.71 0.03 0.38 0.054.07 0.04 0.72 0.051.83 0.03 0.62 0.070.98 0.04 0.19 0.060.39 0.05 0.56 0.360.25 0.04 0.28 5.740.12 0.07 0.25 0.090.70 0.03 0.34 0.031.21 0.06 0.53 0.191.06 0.04 0.19 0.050.27 0.04 1.01 3.381.54 0.03 0.32 0.124.58 0.03 0.11 0.02(a indeterminate-only surface sampletested)0.44 0.03 0.41 0.310.03 0.15 0.05 3.530.95 0.04 0.91 0.441.23 0.04 0.61 0.150.21 0.06 0.93 7.190.61 0.05 0.28 0.090.25 0.16 0.49 0.540.18 0.07 0.52 d.780.17 0.06 0.35 4.03(a positive-disturbed soilsin streamchannel)0.69 0.04 0.06 0.24

——————..—

‘LADB - Los AlamosData Base.‘FSD - FractionalStandard Deviation.

22

SURFACE SOIL CONCENTRATIC)NOF23Spu AND ~s=gh RATIOS

SurfaceConeof 238~

Location (PCvll) FSD’ 238,239pu

2009201420162018204720602065207220732076208221192121

0.0230.00590.0040.2040.0450.0480.0120.2240.3230.0160.0460.0080.041

0.170.320.500.010.110.110.170.0040.050.130.110.330.10

0.050.040.030.050.050.050.040.050.050.040.050.050.06

——————————

‘FSD - FractionalStandardDeviation,

60c0 was &tect~ at 21 locations,outside of GZ,whereas 15ZEUand lssEu were detected at o~y ‘our

locations in situ. The average bOCoareal concentrationarea from ground zero areas was 2.5 + 1.5 nCi/m2.The130c0distributionfor the fallout area does not correlate~th the lsTcs area concentrations.Away from groundzero areas, the correlationcoetlicientfor bOCoand 137CSis 0.05. There was no correlationbetweenbOCoand ‘Srin soils.

Laboratory countingof the soil samplesin tuna cansprovided additional information about the fissionproducts from the Trinity fallout at GZ. The followingradionuchdes:boco,137@133Ba,152Eu,‘S4EU,and 155Euwere detected in most soil samples.Table XII indicatesthe range of soil concentrations of the radionuclidesdetected.The range is widebut not unusualin viewof thedisturbances of the Trinity GZ area. The area wasplowedand bladedin 1945to removematerialsfromthesurface. In particular, the fused sand and soil calledTrinititewas beingpickedup by visitorsas a mementoofthe event.The surface was bladed and the Trinititewasburied in trenches in the GZ area in 1952. Other

TABLE XII

LADBaNo.

TABLEX3

1977 ESTIMATES OF l-cm AND TOTALPLUTONIUM INVENTORY (nCi/m’)

199519982001200320092014201620182026202720282037204720482049205220572059206020652071207220732076208220S4209721152118211921202121

.— -

I*m 2JSPUInventory (I,)

Bkg ( 3).

radionuclidesidentifkdwithlowconfidenceand expectedin falloutgamma-rayspectrawere l“Ce and 12sSb.‘llegelatter radionuclidesare likely from the Chinesenucleartests.

In seiectedsoilsamplesfrom areas offthe WhiteSandsMissileRange,the predominantfissionproductsdetectedwere ‘37CSand ISSEU.These samples are from a largearea includingChupadera Mesa, GallinasPeak, and thefar falloutareas northeastof New MexicoStateHighway14. For laboratory counting,the O-to 5-cm and 10- to15-cm samples were selected for counting for in situ

ACTIVATION AND FISSION PRODUCTS INBULK SOIL SAMPLES AT TRINITY GZ AREA

Soil Sample Rangeof ConeIsotope Interval(cm) (pci/g)

Vo o-55-10

10-15137Ci5 o-5

5-1010-15

133Ba o-55-10

10-151s2Eu o-5

5-1010-150-55-10

10-15

12-6012

0.12-184.2-21

0.52-480.79-16

1.6- 3.80.58 -2.9N.D - 1.5’

12-1300240-270

N.D -34016-7610-15

N.D -17

‘Not detected,

detector calibration.Selected5- to 10-cmsampleswerecounted,but they werefewerin number.

The mean valuesfor the lssEuactivityin soilwere0.17+ 0.12 pCi/g for the O-to 5-cm depth and 0.14 + 0.07pCi/g for the 10-to 15-cmdepth.An analysisofvarianceindicates the means are equal at the 99’%0level ofsignitlcance.The same sampleshave unequalmeans forl’?cs concentrationwiththe greatest amountsin the 0-to

5-cm samples.The equalconcentrationsof 13SEUconcen-trations in the O-to 5-cm and 10- to 15-cmsoil depthsindicate possible movementof Eu deeper into the soilwith time.For a deepersoilsampleof 20 to 25 cm in thesame region but for only one location,the lssEuconcen-tration was 0.23 pCi/g.

D. Natural Radioactivityin Soils

The in situ Ge(Li)detectorsystemdetectsthe gamma-emitting primordial radionuclidesand these radiationscan be usedfor calibrationof the detectorfor energy.Thequantitiesof ‘K are determineddirectly.The quantities

23

of 2.3SUand znTh me determinedfrom the quantitiesof

gamma-emittingdaughterproducts. Use of the daughterproducts assumes radiologicalequilibriumbetween theparents and daughters with minimal or unimportantchemicalredistributionin the soils.

The ‘OKconcentration,listed in Table XIII, averaged17.7+ 0.56 pCi/g for the regionsurveyedwitha rangeofv~ues from 3.4 to 42 pCi/g. The widerange of valuesisconsistent with the variable geologicalfeatures of theregion surveyed. The NCRP report on natural back-ground radiation in the U.S. summarizesthe concentra-tions of major radionuclidesin rock types and soil.23Theexpected range of values would be predicted to bebetwtin 2 pCi/g for carbonate rocks and 40 pCi/g forsalic rocks. The geologicalformationsof the region arecomposedof limestonesand sandstoneswitha smallareaat the top of GallinasPeak beingintrusiverock identiiledas rhyolite. The highest value, 42 pCi/g, was from aregion of volcanic rocks in a canyon area where ‘OKcontent would be expectedto exceed30pCi/g. Soilsforthe total U.S. averaged12pCi/g for insifumeasurementstaken by Lewder et al. in 1964 compared with theaverageof 18pCi/g for this study .24

The concentrationsof the natural radionuclides23%ad znu ~so v~~ within the study region.The 23~h

averageconcentrationfor all in situ locationswas0.94 *0.04 pCi/g with a range from 0.12 pCi/g to 2.8pCi/g.The 236Uconcentrations for in situ locations averaged0.90 + 0.03 pCi/g with a range from 0.32 pCi/g to 2.0pCi/g. The highestvalues of 23~h were detected at thetop of Gallinas Peak where intrusive rocks occur. Thehighest uranium value was detected in an area thatintegrateswater runoff in a basin area. Areas of exposedlimestonewhere soilswere relativelythin contained the

TABLE XIII

SOIL CONCENTRATIONS OF NATURALLYOCCURRING GAMMA-EMITTERS

Mean Cone. RangeRadionuclide n (pCi/g)+ S.E. (pci/g)

40K 101 17.7 + 0.56 3.4-42232~ 101 0.94 * 0.04 0.14 -2.8238u 101 0.93 * 0.03 0.32 -2.0

lowestconcentrationsof232Thand 2SBU,as expectedfromliteraturevalues.23’X

IL DATA SUMMARYFOR SOILS

The separation of the overall data base into smallerlocationsof measurementof radionuclidesgeneraUyfol-lowed topographic areas of the fallout area from theTrinitytest. An artificialityof the boundaryselectionwasthe use of roads or a propertyboundary,whichtends toresult in a mixture of topographic features. However,directions and distances from GZ and land use allcontributedto the choiceof boundariesfor separatedatatreatment.

The areas are boundedin Fig. 7 by solidlines.TrinityGZ is illustrated in Figs. 4 and 11. Located within aspecial fenced area on the White Sands MissileRange,TrinityGZ is the area of grounddisturbanceIetlfromtheinitial test. Figure 9 indicatesthe samplinglocationsforthe White Sands Missile Range, Bingham are% andChupadera Mesa. Earlier surveys by Larson et al. andspecial studies by Hakonson et al. indicated localizedareas of higher fallouton Chupadera Mesa.b$gFigure 7includes the sample locations for the far fallout area.Figure 10 indicates the location of samples in the SanAntonio are% whichis west and out of the falloutpath.

The soildata for each area are summarizedin TablesXIV through XIX. The results listed in the tables aresummariesof statisticaltreatmentof the data by area todeterminemeansand standard errors (standarddeviationof the mean).23The dates associated with the 239’249f%I

determinationsare the data from studiesby OlafsonandLarson in 1948and 1950,Los Alamos in 1972,EPA in1973and 1974,and LosAlamosin 1977and 1983.Alsonoted is the depth of soil samples taken because thesamplingschemesused by differentinvestigatorsvaried.

A. Plutoniumin Soils

From AppendixD, the levelof 23g-XOPuin soilsfromworldwidefallout depositedin northern New Mexicois0.008 + 0.01 pCi/g. Of the areas listed in Tables XIVthrough XIX, only the San Antonio Area contains~g-z’opu~ Soilsat concen~ations as low as Northern

New Mexicofalloutlevels.The other areas of the falloutzone ~ cont~ ZJ9-Z’OPUaboveworldwidefalloutlevels.

The no action levelproposed by the DOE RemedialAction Programs for ZW,MOPUis 100 pCi/g. The o~Y

24

%/

❑ ✎•! .-””.” 0

on ~ 00° ❑ ❑

❑

❑❑ o

0

❑❑

.CzNmnum

/ oF&v.fuT

mm9ANmMIMI.S

❑ “g:”RANGE

❑ ❑

fii %=t?J“Y lluIdlYCzm II w

I I I CARR1’mza IFig. 9. WhiteSandsMt!wileRange,Bingham,and ChupaderaMesa sanqdklocations.

/

❑

❑

SANANIUNIO

&NOE

Wnrrz

\

SANOSMlmn.11RANGE

I I

Fig. 10. Sampk locationsfor the San Antonioarea.

area exceedingthis levelof plutoniumis the controlledinner fenced area of GZ. The EPA has proposed ascreening level for no action of 200 nCi/m2, which isequivalentto about 15 pCi/g in the top l-cm layer ofsofl. Meas~ements of 23*24PUin controlled ~eaS of

GZ exceed this proposed limit.Measurementsmade in1972 within 1 km of GZ in the falloutpath exeeed thislimi? but EPA measurementsin 1973 and Los Alamosmeasurementsin 1972do not exceedthe limits.

B. Cesium-137in Soils

The amounts of 137CSin soilsof the GZ area exceedthe levelsfound in soilselsewherein tie U.S.2S$27HOW-ever, the amounts detected by in situ measurementsonthe White Sands MissileRange and other fallout areasare within the range of values reported for the arealdistributionsof worldwidefallou~Table XX listsa rangeof 19 to 305 nCi/m2from Californiato Comecticut. Ifthe measurements at San Antonio are assumed to belevels representing worldwidefallou~ the White Sands

25

Radionuclide

1 AHLE WV

GROUND ZERO SURFACE MEASUREMENTS

60c0

137(1~

152EU

Natural gammaTotal gamma

40KZJzTh2311u

239,240pu

Inner fence, O-1 cm1-6 cm0-15 cm15-30 cm30-45 cm

Betweenfences, O-1cm1-6 cm15-30 cm

Inner fence, O-2.5cmCombined,O-5cm

5-10 cm10-15cm

137CS

Inner fence, O-1cm1-6 cm0-15 cm15-30 cm30-45 cm

Betweenfences, O-1cm1-6 cm4-10 cm10-15cm

N

666

66

666

11111

119

112333

111113333

Mean +-S.E.’ Min Max

5554 + 3094 nCi/m28104 + 3772 nCi/m2

107 200 + 54 400 nCi/m2

7.9 + 0.7 @l/h131+ 62 ~R/h

24 + 4.4 pCi/g0.86 * 0.03 pci/g0.60 + 0.13 pCi/g

(1983) 22.8 + 0.2 pCi/g(1983) 156+ 15 pCi/g(1983) 23.7 + 0.4pCi/g(1983) 256 + 3 pCi/g(1983) 0.4 + 0.02 pCi/g(1983) 5.8 + 9.5 pCi/g

(1983) 1.14+ 2.9 pCi/g(1983)0.0053 + 0.003 pCi/g

(1972) 127+ 180 pCi/g(1977) 31 *31 pCi/g(1977) 34+ 30 pCi/g(1977 67+ 116 pCi/g

16.5+ 3.3 pCi/g21.8 + 4.4 pCi/g12.6+ 2.5 pCi/g21.5 + 4.3 pCi/g0.67 + 0.19 pCi/g0.54 ●0.37 pCi/g0.64 + 0.48 pCi/g0.33 * 0.12 pCilg0.07 * 0.41

0488842

5.59.8

120.780

b

b

b

b

b

b

0.040.020.0020.043.80.05< MDA

bbbbb

0.170.290.22

-0.33

19 30023 000

340000

10.0397

430.970.88

b

b

b

b

b

288.80.01

25564.857

201

b

b

b

b

b

0.921.190.320.49

TABLE XIV(cont)

Radionuclide N

152EU

Inner fence, O-1 cm1-6 cm0-15 cm15-30 cm30-45 cm76-91 cm106-122cm

Betweenfences, O-1cm1-6 cm

————————

‘S.E. - Standard Error.bSingleobservation.

112222288

Mean + S.E.’ Min Max

MissileRange, Chupadera Mes~ and Far Fallout Zoneare 2.4, 4.2, and 2.2 timeshigherthan levelsexpectedincentralNew Mexico.

Cesium also can be used as an indicator of the slowchanges in falloutdistributionwith time. Measurementsby the in situ detectoron ChupaderaMesaweremadefordiiTerentland forms at severallocations.The ChupaderaMesa area has severalclosed drainage collectionpointswhere the water and associated sedimentsfrom rainfallrunoff collect. Measurementswere made on the slopesabove a collectionpoint and on the sedimentbed in thedry collection areas. Table XXI summarizes the datataken for such drainage systems on Chupadera Mesa.The arithmetic mean values for IJTCSon slopes above

drainages and their associated collectionpoints are notequal with a 99.5% contldenceusing Student’st-test forequal means. The data suggest that after 32 years thecesium bound to soils is slowly being transported intowater and sedimentcollectionpoints.However,the proc-ess appearsto be slowand any increasedarealconcentra-tion in the collectionsedimentpoints will be offset byradioactivedecay with half of the activitydisappearingevery 30.2 years.

C. Strontium-90in Soils

Measurementsof 90Srin soilsduring the 1977surveywere restricted to relatively few samples because ofanalyticalcosts. From the limiteddata, comparisonsof

284 + 29 pCi/g245 k 25 pCi/g382 + 167 pCi/g

1013+ 79 pci/g225 + 80 pCi/g

12+ 16 pCi/g2.2 + 2.4 pCilg20 + 18 pCi/g18+ 14 pCi/g

b

b

264957169

0.50.43.43.5

b

b

5011069282243.9

5946

the 90SrinZone with

soilsof Chupadera Mesa and the Far Falloutmeasurementsof worldwidefalloutin soilsat

various locations in the U.S. indicate a clear influencefrom the Trinity test. Table XXII summarizesdata forlocationsin mountainstates of the U.S.; 90Srlevelsin thefallout zone from the Trinity test range from 10 to 40timesthose both north and southof centralNew Mexico.

III. AIRBORNE RADIOACTIVE MATERIALS

Airborne radioactive materials measurements atTrinity site and in the falloutzone are extremelylimited.During the 1973 and 1974 survey by the EPA, a 10-month air samplingwas conductedon ChupaderaMesaand at Socorro, New Mexico,a communityout of theintluence of the Trinity test.13Air concentrations ofplutonium at both locations were equal, but isotopicratios at Chupadera Mesa indicated the Trinity testplutoniumcontributedthemajor activitywhileworldwidefalloutcontributedthe major activi~ at Socorro.13

Table XXIII includesplutoniumconcentrationsin airsamplestaken at GZ and at a controlsite5.2km southofGZ in 1983. Also included are the air concentrationscalculated for resuspendedplutonium(see AppendixDfor details).

Comparison of the calculatedresuspendedplutoniumon Chupadera Mesa with the measured valuesindicatesthe calculations overestimate the actual amount by a

27

TABLE XV

WHITE SANDS MISSILE RANGE FALLOUT ZONE SOIL MEASUREMENTS

Radionuclide

‘Be60c0

137fl~

152J7U

155EU

9SNb

95zr

103Ru

Natural gammaTotal Gamma

40K

238u

232~

238pu

239pu (1948)‘9pu (1972)

(1972)(1972)(1973)

(1977)(1977)(1977)

‘Sr

137c~

DepthN (cm)

2222222222222222

2323

22...

22

7------

4444

13

767

443

121210

—-——-——-—-—---

---—

—-—----

0-55-10

10-150-2.50-2.5

2.2-1010-300-5

0-55-10

10-15

0-55-10

10-15

0-55-10

10-15

Mean + S.E? Min Max

5.7 * 1.2 nCi/m227 + 23 nCi/m2

162+42 nCi/m277 * 77 nCi/m5.5 * 4.0 nCi/m23.1 + 0.26 nCi/m22.5 + 0.27 nCi/m2

0.14 + 0.08 nCi/m2

7.8 + 0.65 @/h7.9 + 0.56 @/h

19 * 1.4 pci/g0.88 + 0.05 pci/g0.94 + 0.08 pci/g

0.55 + 0.43 pCi/g0.38 + 0.38 pCi/g

0.009 * 0.005 pci/g1.32+ 0.50 pCi/g

63 + 63 pCi/g65 +65 pCi/g15 * 15 pCi/g99 + 84 nCi/m2

(1.42 pCi/g)10 * 9 pci/g

7.6 + 7.3 pCi/g29 +29 pCi/g

1.8+ 1.4 pCi/g0.38 + 0.08 pCi/g0.70 + 0.46 pCi/g

4.5 * 2.3 pCi/g4.9 + 2.6 pCi/g0.8 + 0.7 pCi/g

TABLE XVI

BINGHAM AREA SOIL MEASUREMENTS,US HIGHWAY 380 CORRIDOR

DepthRadionuclide N (cm) Mean + S.E.”

7Be 2 —. 5.8 * 5.8 nCi/m260c0 2 —. 0.6 + 0.6 nCi/m2137c~ 2 —- 52 + 28 nCi/m2gsNb 2 --- 11.4* 0.19 nCi/m2Natural gamma 2 --- 5.6 + 0.2 ~R/hTotal gamma 2 —- 5.8 + 0.1 ~R/h40K 2 -— 12 + 0.22 pCi/gzgzTh 2 --- 0.68 + 0.035 pCi/g23Eu 2 --- 0.80 + 0.05 pCi/g239,240pu(1g48) 2 0- 1.5 0.9 ●0.4 pCi/g

(1972) 2 0.-2.5 0.21 + 0.08 pCi/g(1972) --- 2.5-10 0.43 + 0.32 pCi/g(1972) --- 10-30 0.085 + 0.085 pCi/g(1973) 14 0-5 5.0 + 3.3 nCi/m2/

(0.070 pCi/g)c——————

‘S.E. - Standard Error.b

TABLE XVII

CHUPADERA MESA SURFACE SOIL MEASUREMENTS

Natural gammaTotal gamma

‘K232T~

231U

221pu

“90z401% (1948)(1950)(1972)(1972)(1972)(1973)

(1977)(1977)(1977)(1977)

%r

N—

4949494949494949

4949

494949

1915153

10933

...

...

1914163

73

274

161

Depth(cm)

...

.-.

.-

...--—.-..—

--...

...

...

...

0-55-10

10-1515-200.-2.50-2.50-2.5

2.5-1010-300-5

0-55-10

10-1515-20

0-510-15

0-55-10

10-1520-25

“S.E. - StarrdardError.

Mearr + S.E.’ Mirr

8.8 * 1.1 nCi/m20.58 + 0.16 nCi/m2280k 30 nCifm2

0.48 + 0.48 nCi/mz4.2 k 2.4 nCi/m2

4.65 + 0.15 nCi/m’2.55 + 0.15 nCi/ml0.28 ~ 0.07 nCi/ml

6.7 k 0.24 @/h8.2 + 0.32 @/h

16 + 0.58 pCi/g0.85 + 0.04 pCi/g0.88 * 0.04 pCi/g

0.083 + 0.020 pCi/g0.023 * 0.013 pCi/g0.006 +.0.004 pCi/g0.003 + 0.003 pCi/g

3.1 * 1.3 pci/g3.2 + 1.2 pCi/g

0.80 + 0.34 pCi/g0.15 * 0.10 pci/g

0.033 * 0.015 pCi/g20.6 k 4.3 nCi/m2

(0.29 pci/g)’ ,1.7 * 0.41 pCi/g

0.38 k 0.27 pCi/g0.11 * 0.07 pci/g

0.033 * 0.03 pci/g

2.3 + 1.0 pCi/g0.76 + 0.47 pCi/g

2.81 + 0.52 pCi/g0.16 + 0.02 pCi/g0.04 + 0.02 pwg0.05

Max

Radionuclide

‘Be60c0

137c~

95Nb

95zr

103Ru

Natural gammaTotal gamma

40KzJZTh238u

238pu

239,240pu

(1950)(1973)

(1977)

9otJr

137c~

TABLE XVIII

FAR FALLOUT ZONE SURFACE SOIL MEASUREMENTS

N

272727272727

2626

272727

1286

18

24

1498

4111

1054

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