-
FINAL OU2 Baseline Ecological Risk Assessment Report
Formosa Mine Superfund Site Douglas County, Oregon
R10 AES (SMALL BUSINESS) CONTRACT NO. 68S70304
Task Order No. 047B
Prepared for: U.S. Environmental Protection Agency
Region 10 1200 Sixth Avenue, Suite 900 Seattle, Washington
98101
Prepared by: CDM Federal Programs
1218 Third Avenue, Suite 1100 Seattle, Washington 98101
Parametrix 411 108th Avenue NE, Suite 100 Bellevue, Washington
98004
July 11, 2014
-
FINAL
OU2 Baseline Ecological Risk Assessment Formosa Mine Superfund
Site
Douglas County, Oregon
Tony C. Gendusa Ph.D. CDMSmith Ecological Toxicologist
QA ReviawbY!( Kim Ziiis CDM Smith QA Officer
~woved by: Michael C. Allen CDM Smith Project Manager
R-10 AES (SMALL BUSINESS) CONTRACT NO. 68-S703-04
Task Order No. 047B
cfv/7 /P,;l.~lf Date
~ 10 z,,,,j Date
-
Signature Page
Thispageintentionally leftblank
ii
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Table of Contents
Section 1 Introduction
.................................................................................................................................
11 1.1 PurposeandApproach
............................................................................................................................................11
1.2
SiteDescription...........................................................................................................................................................12
1.3 ContaminantSources
...............................................................................................................................................13
1.3.1
SurfaceWater...............................................................................................................................................13
1.3.2 Groundwater
................................................................................................................................................13
1.4
EcologicalInvestigations........................................................................................................................................14
1.5 OrganizationofthisReport
...................................................................................................................................14
Section 2 BERA Problem
Formulation....................................................................................................
21 2.1 StressorIdentification
.............................................................................................................................................21
2.1.1
ChemicalsandExposureMediaofPotentialConcern................................................................22
2.1.2 RefinementofChemicals
ofPotentialConcern.............................................................................22
2.1.3
SummaryofExposureAreas.................................................................................................................22
2.2
EcologicalResourcesatRisk.................................................................................................................................23
2.2.1
Habitats...........................................................................................................................................................23
2.2.1.1
AquaticHabitats..........................................................................................................................23
2.2.1.2 Fateand
TransportwithinAquaticHabitats..................................................................27
2.2.1.3
TerrestrialHabitats....................................................................................................................27
2.2.1.4 Fateand
TransportwithinTerrestrialHabitats............................................................28
2.2.2 EcologicalReceptors
.................................................................................................................................28
2.2.2.1
AquaticReceptors.......................................................................................................................28
2.2.2.2
TerrestrialReceptors................................................................................................................29
2.2.2.3
FederallyListedSpecies........................................................................................................
210
2.3
EndpointsandRiskQuestions/Hypotheses................................................................................................
211
2.3.1 Objectivesand AssessmentEndpoints
..........................................................................................
211
2.3.1.1 SurfaceWaterBasedAssessmentEndpoints
.............................................................. 212
2.3.2
MeasurementEndpoints......................................................................................................................212
2.3.3
RiskQuestions/Hypotheses................................................................................................................
213
2.4 ConceptualSiteModel
..........................................................................................................................................
214 Section 3 BERA Exposure
Assessment....................................................................................................
31
3.1 ExposureMedia
..........................................................................................................................................................31
3.2 ExposureAreas
...........................................................................................................................................................31
3.3
DataUsedintheBERA.............................................................................................................................................31
3.4 WaterQuality Parameters
.....................................................................................................................................32
3.5
ScreeningofChemicalsofPotentialConcern................................................................................................33
3.5.1
SurfaceWaterExposurePointConcentrations.............................................................................33
3.5.2
EcologicalScreeningLevels...................................................................................................................34
3.5.3
ChemicalScreeningandSelectionofFinalCOPCs.......................................................................34
3.6 ContaminantFateand
Transport........................................................................................................................35
3.6.1
EnvironmentalPersistence....................................................................................................................35
3.6.2 Bioconcentration Potential
....................................................................................................................35
3.6.2.1
EvaluationofMercuryasaCOPC.........................................................................................36
3.6.3 Bioavailability
..............................................................................................................................................38
3.7
ExposureofEcologicalReceptors.......................................................................................................................39
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Table of Contents
3.8
UncertaintyAnalysis..............................................................................................................................................310
Section 4 BERA Effects Assessment
..........................................................................................................41
4.1
ToxicityReferenceValues......................................................................................................................................
41
4.2
UncertaintyAnalysis................................................................................................................................................
43
Section 5 BERA Risk
Characterization.....................................................................................................51
5.1 RisksBasedonDirectExposure
.........................................................................................................................
51
5.1.1
RiskstoAquaticLife..................................................................................................................................
52
5.1.1.1
RisksBasedonSurfaceWaterCOPCConcentrations.................................................52
5.1.2
RisktoUpperTrophicLevelReceptors............................................................................................
54
5.2 OtherSupportingData
............................................................................................................................................
54
5.2.1
FishCommunityData...............................................................................................................................
54
5.2.1.1
HistoricalData..............................................................................................................................
54
5.2.1.2
RecentData....................................................................................................................................
55
5.2.2 BenthicMacroinvertebrateCommunityData
...............................................................................
57
5.2.2.1
HistoricalData..............................................................................................................................
57
5.2.2.2
RecentData....................................................................................................................................
58
5.3 RiskSummary
...........................................................................................................................................................514
5.3.1
RisktoAquaticandWaterDependentReceptors.....................................................................514
5.3.2 ResponsestoRiskQuestions
..............................................................................................................514
5.3.3 SpatialExtent
ofImpairment..............................................................................................................515
5.3.4 SummaryofRiskstoAquatic
Life.....................................................................................................516
5.4
UncertaintyAnalysis..............................................................................................................................................518
5.5 EcologicalIssuesRelatingto
RemedialAlternatives...............................................................................519
5.6 ConclusionsoftheOU2BERA
............................................................................................................................520
5.6.1 EvaluationofApril2014 SurfaceWaterData
.............................................................................520
5.6.2
EvaluationofBioticLigandModel....................................................................................................520
Section 6 References
.....................................................................................................................................61
List of Tables Table 11 Sampling Locations and
DatesforSurfaceWaterSamples Table21 Wildlife and Plants Found atthe
Formosa MineOU2and VicinityTable22 Federally Listed,Candidate
Species,and Speciesof Concernand Potential to Occur
atthe Formosa MineOU2andVicinityTable23
RelationshipbetweenEndpointsandRiskQuestionsfor the Formosa
MineOU2
BERATable31 StatisticalSummaryfor SurfaceWater
AnalyticalDissolvedResults and Selection
of Chemicals of Concern Table32 Summaryof WaterQuality
ParametersbasedonFieldSampling Table33 Summaryof Chemicals of
PotentialConcern Table34 Summaryof MercuryAnalytical ResultsTable41
Summaryof Aquatic LifeScreening Criteria Table42 HardnessandSulfate
AdjustedSurfaceWaterToxicity ReferenceValues,Middle
CreekTable43 HardnessandSulfate AdjustedSurfaceWaterToxicity
ReferenceValues,South
Fork MiddleCreek
iv
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Table of Contents
List of Tables (continued) Table44 HardnessandSulfate
AdjustedSurfaceWaterToxicity ReferenceValues,Middle
Creek Reference Table45 HardnessandSulfate
AdjustedSurfaceWaterToxicity ReferenceValues,South
Fork MiddleCreek Reference Table46 Summaryof
ChronicSurfaceWaterToxicityReferenceValues Hardness
Adjusted byExposureArea Table51 ChronicHazardQuotients
byLocation for FishinMiddleCreek Table52 ChronicHazardQuotients
byLocation for FishinSouthFork MiddleCreekTable53 SalmonidSpecific
HazardQuotients Table54 TotalNumberofFishObservedduring Historical
andRecent Surveys Table55 PredictiveModeling Scores and
ConditionsBased onBMIData Table56 TotalNumberofBMITaxa
atMiddleCreekSamplingLocations Table57 TotalNumberofEPTTaxa
atMiddleCreekSamplingLocations Table58 TotalNumberofBMITaxa at
South ForkMiddle Creek Sampling Locations Table59
TotalNumberofEPTTaxa at SouthForkMiddleCreek Sampling Locations
Table510 Total NumberofBMITaxa at Reference Sampling Locations
Table511 Total NumberofEPTTaxa at Reference Sampling Locations
Table512 Habitat Characteristicsof theEcologicalSamplingLocations
Table513 ToxicityValuesPotentialTRVs forSurface WaterCOPCsBasedon
Protection of
SalmonidFishandBMI Table514 ChronicHazardQuotients by Location
for FishinMiddleCreek Table515 Chronic HazardQuotients by Location
for FishinShouldFork MiddleCreek
List of Figures Figure11a Ecological Sampling Locations
Figure11b Ecological Sampling Locations Figure 11c Ecological
Sampling Locations Figure21 OU2Exposure Model for Human and
Ecological Receptors Figure51 Total NumberofBMIOrganismsinMiddle
CreekandReference Locations Figure52 Total NumberofBMIOrganisms in
South Fork Middle Creek andReference
Locations Figure 53 Total Numberof BMITaxain Middle Creek and
ReferenceLocations Figure54 Total NumberofBMITaxain South Fork
MiddleCreek and Reference Locations Figure55 Numberof EPT Taxain
MiddleCreek andReferenceLocations Figure56 Numberof
EPTTaxainSouthFork Middle Creek and Reference Locations Figure57
Concentrationsof
DissolvedMetalsandBMIMetricswhereSampledConcurrently Figure58a
Impairment ofStreamsbasedon BMICondition Scores and
EcologicalRiskHQs Figure58b Impairment ofStreamsbasedon
BMICondition Scores and EcologicalRiskHQs Figure58c Impairment
ofStreamsbasedon BMICondition Scores and EcologicalRiskHQs
v
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Table of Contents
List of Appendices AppendixA Surface WaterAnalyticalDataResults
and FieldMeasurements AppendixB SiteSpecific HardnessCalculations
Appendix C Evaluationof AcuteRisk AppendixD
BenthicMacroinvertebrate Datafrom the BLM/USU
NationalAquaticMonitoring
Center
vi
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CCC
Acronyms % percent ARD acid rock drainage BERA baseline
ecological risk assessment BLM Bureau of Land Management BMI
benthic macroinvertebrate CaCO3 calcium carbonate
Criterion Continuous Concentration CF conversion factor COI
chemical of interest COPC chemical of potential concern CSM
conceptual site model CVAAS cold vapor atomic absorption
spectrometry DO dissolved oxygen DOGAMI Oregon Department of
Geology and Mineral Industries EA exposure area EPA United States
Environmental Protection Agency EPC exposure point concentration
EPT Ephemeroptera, Plecoptera, Trichoptera ERA ecological risk
assessment ESL ecological screening level FS feasibility study HQ
hazard quotient mg/kg milligrams per kilogram mg CaCo3/L milligrams
of calcium carbonate per liter MIW mining influenced water MREF
Middle Creek Reference location NMFS National Marine Fisheries
Service NRWQC National Recommended Water Quality Criteria OAR
Oregon Administrative Rules O/E observed to expected ODEQ Oregon
Department of Environmental Quality ODFW Oregon Department of Fish
and Wildlife OU Operable Unit PREDATOR Predictive Assessment Tool
for Oregon PRGs preliminary remediation goals RI/FS remedial
investigation/feasibility study SFREF South Fork Middle Creek
Reference location SLERA screening level ERA TRVs toxicity
reference values UCL upper confidence limit g/L micrograms per
liter S/cm microsiemens per centimeter USFWS U.S. Fish and Wildlife
Service USGS United States Geological Survey
vii
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viii
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Section 1 Introduction
Aspartoftheremedialinvestigationandfeasibilitystudy(RI/FS)forFormosaMine
OperableUnit2(OU2),UnitedStatesEnvironmentalProtectionAgency(EPA)isconductingabaseline
ecologicalriskassessment(BERA).EvaluationsintheOU2BERAassesspotential
threatstotheenvironmentthatmayexistresultingfromthereleaseorthreatenedreleaseofcontaminantsat
or fromOU2if no remedialactionis taken.Conclusions(Section5.6)
oftheOU2 BERA will beintegratedintothe futureOU2RIreport,which will
bepreparedinboth draftandfinal versions.TheDraftRIfor
OU2willinclude an evaluation of
groundwaterandsurfacewaterdatacollectedfromOctober2009throughApril2014.
TheFinalRIforOU2
isscheduledtoincorporateinformationfromtheFormosaAditremovalactionbeingconducted
in2015 bytheBureauofLand Management(BLM)thatis designedto
containminepoolwaterwithin adit.Intheinterim,datawill
becollectedtoassesstheeffectstosurfaceandgroundwaterresulting from
sealing theFormosa1Adit.EPAanticipates atleast threetofiveyearsfor
waterwithinthemine pooltoreachequilibrium with the new hydraulic
conditions beforeeffects wouldbeseenin downgradientsurfacewater.
OU2includes surfacewater,sediment,groundwater,underground workings,
and adit water
drainageassociatedwiththeFormosaMine.Itexcludesthesurfaceandsubsurface
minewastes (tailings andwasterock)andsoils
thatweredepositedoutsideofthemine
workings,representedbyOU1andevaluatedas partoftheOU1RI/FS (CDM2012
andCDMSmith2013).Seethe
OU1RIandFSdocumentsforinformationonpreviousinvestigations conducted
attheFormosaMineSitesince1988. TheOU2BERAisbased
onanevaluationofsurfacewaterdata,whereas theOU2RI will includean
evaluationof groundwater andwill includea human healthrisk
evaluation. TheOU1ecologicalriskassessments(ERA)werereportedinthe
OU1RI(CDM2012) toquantifycurrentorpotentialthreats
toecologicalreceptorsfromenvironmentalcontaminantsintheabsenceofanyremediationandto
helpdeterminewhetherremedialactionsarewarranted.TheOU1ERAfocusedonterrestrialhabitatsandreceptorspotentiallyassociatedwith
theformerminesite.The OU1ERAincludeda screeninglevelERA (SLERA)for
aquaticenvironmentsadjacenttotheFormosa Minesite. The
SLERAevaluationwas
basedoncomparisonsofdissolvedconcentrationsofselectedmetalsinsurfacewaterat
seepandstreamlocations
intheheadwatersofMiddleCreekandSouthForkMiddleCreektosurfacewaterecologicalscreeninglevels
(ESLs).Dissolved
metalsconcentrations,whicharethemosttoxicform,werecomparedto
chronicNationalRecommended WaterQualityCriteria(NRWQC)establishedby
EPA fortheprotectionof
aquaticlife.TheSLERAidentifiedseveralchemicalsofpotentialconcern(COPCs)fortheaquaticecosystems.Basedonthesefindings,aBERAwasrecommended
for OU2.ThisdocumentpresentstheOU2BERA.
1.1 Purpose and ApproachERAsareperformedtodetermine
ifecologicalreceptorsareat risk
fromexposuretositerelatedcontamination.ERAsaremostoftenconductedusing
a phasedapproachthat followsEPAguidancefor conducting ERAsat
Superfundsites.The approachusedtoconductthisERAfollows Ecological
Risk Assessment Guidance for Superfund: Process for Designing and
Conducting Ecological Risk Assessments(EPA1997).
ItisgenerallyrecognizedbyEPA(1997) andothers
thatthosemethodsforconducting
11
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Section 1 Introduction
ERAsmustbesitespecific.TheEPAguidance(1997)isthereforenotadetailedstepbystep"cookbook"
butinsteadprovidesrecommendationsonERA
componentstobeconsideredandgeneralapproachesforperforming ERAs.As
muchaspracticable,themethods,recommendations,and
terminologyofthe1997 EPAguidanceareusedtoconducttheOU2BERA.
ThefirstphaseoftheERA isa SLERA.TheSLERA is usedtodetermine
iffurtherinvestigationiswarrantedbasedonareasonablepotentialforecologicalreceptors
tosufferadverseeffectsas aresultofexposuretositerelated
contamination.If theSLERAdeterminesthatadverseeffectsare
likely,thenthenextphaseoftheERAprocessiswarranted.Thissecondphase
istheOU2BERA.Whereindicated bytheresultsofthe SLERA, the
BERAisperformedto describe
ecologicalrisksandtoreducetheuncertainties associated with
conservativeriskestimationsin theSLERA. As the initial step for
ecological evaluations, a SLERAwas conductedasa componentofthe
OU1RI(CDM2012). TheSLERAincludedan
evaluationofselected,potentiallysiterelatedmetals(cadmium,copper,lead,
nickel,and zinc)insurfacewaterinthe upperreaches
ofMiddleCreekandSouthForkMiddleCreek.BasedontheresultsoftheSLERA,cadmium,copper,andzincwereidentifiedasCOPCsforaquaticecosystemsinOU2,andaBERAwasrecommendedtoevaluatefurthertherisktoecologicalreceptorsinOU2.
TheOU2BERArefinestheconservativeassumptionsusedintheSLERAtoprovidemoreconfidentestimationsof
risk,provide informationthatcanhelp
establishremedialpriorities,andservesasa scientificbasis
forregulatory andremedialactionsfor thesite.TheOU2BERAis
basedonanapproach usingmultiple linesof evidence whilethe
SLERAtakes a morestreamlinedapproachtoestimaterisks. Aprimaryline
ofevidenceforboththe SLERAandtheBERA isa
comparisonofcontaminantconcentrationsin
sitesurfacemedia(e.g.,surfacesoil)toconcentrationsassociatedwithadverseeffects.Following
EPAguidance,
theSLERAconservativelycomparesmaximumconcentrationsofcontaminantsmeasuredinvarious
mediatoconservativebenchmarkconcentrations,primarilythosetermedESLs.TheOU2BERAdiffers
fromthisconservativeapproachbygenerallyassessinga range,
e.g.,themean andmaximum,ora morerealisticandreasonable
upperlevelpointestimate,e.g.,upper95thpercent(%)confidencelimitofthearithmeticmean(95%
upperconfidencelimits[UCL])ofmeasuredcontaminantconcentrations.Theseexposureconcentrationsarethencomparedtolessconservativeeffectsconcentrations(termedtoxicityreference
valuesorTRVs) that,totheextentpossible,aredirectly
relevanttositespecificreceptorsand exposurescenarios.
IntheBERA,theseprimarylinesofevidencearesupplementedbyotherssuchas
foodwebmodeling,siteobservations,biologicalsurveys,ortoxicity
testing.Finally,additionalevaluations or investigationsmaybe
performedattheFSstageoftheRI/FSprocessthat
furtherrefineinformationpresentedintheBERA
tospecificallyaddressremedialdesignneeds.
1.2 Site
DescriptionTheFormosaMine,locatedinsouthwestOregoninDouglasCounty,
iswithin theCoast Range
KlamathMountainsatelevationsbetween3,200and3,700feet abovemean
sealevel.Thearea isheavilyforestedand consistsofupland, riparian,
and
aquatichabitats.ThefourmajorwatershedsinthevicinityincludeUpperMiddleCreekandSouthForkMiddleCreek,whichareperennialstreamsthataretributariestoMiddleCreek,andRussellCreekandWestForkCanyonCreek.TheUpper
MiddleCreekandSouthForkMiddleCreek watershedsare
theprimarysurfacewater drainagesintheareaof
interestfortheOU2BERA.Based onsurfacewater
sampling,RussellCreekandWestForkCanyonCreek,north
andeastoftheFormosaMine,respectively,arenotaffectedbythemine.
12
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Section 1 Introduction
1.3 Contaminant Sources The primary contaminantsources are
minematerials that contain
sulfideminerals.Exposureoftheseminematerialstoprecipitationandoxygenresultsinsulfideoxidationandsubsequentrelease
ofdissolvedmetalsandmetalloids to theenvironment.
Thisprocessisreferredtoasacidrockdrainage(ARD) and isthe dominant
contaminantreleasemechanism.Thegeneraltermmininginfluencedwater(MIW)isusedtodescribe
ARDonceittransportsfromthe generationsource. Mining was
conductedprimarilyby
undergroundmethods,whichresultedinconstructionofanetworkofundergroundvoids,partialbackfillofundergroundvoidswith
ARD generatingminematerials,andplacementofARD generating mine
materialsonthesurface.Reclamationofthemine between1993and1995
includedremovalofformer mineralprocessingfacilities,haulageoflow
gradeoreandtailings intotheunderground mine, regrading of waste
rock and other minematerialslocatedonthesurface,constructionofa
tailingsrepositoryinaformerwaterstoragepond(theencapsulationmound),andrevegetation.
1.3.1 Surface Water Surfacewatersamplinghas
beenconductedtoassesseffectsof theMIWdischarge
onsurfacewater,examine contaminant transport pathways, and evaluate
the downstream extentofeffectstosurface waterquality. Table 11
providesasummaryofmeasurementstakenbyeventandlocation.SamplingeventsfromOctober2009throughJanuary2011arereportedintheOU1RIdocument.WatermeasurementsfromOctober2009throughApril2014areincluded
in theOU2 RIreport.The FinalOU2RIreportwilldocumentall
waterdataincludingpostremoval action monitoring data.
Basedonthesedata,surfacewaterqualityinbothMiddleCreek
andSouthForkMiddleCreekisaffectedbyMIW.Aprimarysourceofcontaminantsin
surfacewatersisMIWdischargesfrom groundwater tosurfacewater.
InMiddleCreek,mostMIWgroundwaterdischargingtosurfacewaterhassimilarcharacteristics
tothe Formosa1 adit discharge,
stronglyacidiccalciumsulfatewaterwith high
concentrationsofiron,copper,zinc,andothertracemetals.InSouthForkMiddleCreek,MIWdischarging
fromgroundwater
tosurfacewaterisstronglyacidiccalciumsulfatewaterwith high
concentrationsofcopper,zinc,andothertracemetalsandrelativelylowerironcontentascomparedto
theUpperMiddleCreekarea. 1.3.2 Groundwater
Datafromgroundwatersamplingshowthepresence of alluvial
andbedrockgroundwatersystems, bothof which aretransporting
inorganicstosurfacewater.The alluvialgroundwatersystemis
presentwithindiscretealluvial
aquifersthatarelocatedwithinunconsolidatedsedimentsin thebase
oftributarydrainages.Thebedrockaquiferisafracturecontrolledaquiferhosted
bymetavolcanicrocks. Findings of the limited
groundwaterinvestigationsuggestthat
leakagefromthewaterdiversionsystemattheFormosa1aditis
rechargingthealluvialaquifer and contributing
toMIWdischargesfromgroundwatertosurfacewaterintheupstreamreachesofUpperMiddleCreek.Althoughthereispotentialforthebedrockaquifertobeaffectedinthisarea,
datafrombedrockmonitoringwellsMW8andMW2in thearea suggest
theseeffectsareminor. Incontrast,thebedrockaquifer
isaffectedwestofthe encapsulationmound in
theheadwatersofSouthForkMiddleCreek.GroundwatersamplesfromMW5indicate
groundwaterisacidicand
13
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Section 1 Introduction
containshigh concentrationsof
cadmium,copper,zinc,andotherinorganics.Thealluvialgroundwatersysteminthe
headwaters areaof
SouthForkMiddleCreekisaffectedbyMIW,withsimilarwater qualityto
thebedrock groundwatersystem.
1.4 Ecological InvestigationsEcologicalstudieshaveincluded
benthicmacroinvertebrate (BMI) sampling and
fishsurveys/sampling.BMIsamplingwasconductedatover20locationsin1999
by BLMand OregonDepartment
ofEnvironmentalQuality(ODEQ)(BLM/ODEQ2000).Dataobtainedduringthis
samplingeventwerecomparedto
earliersamplingthatwasconductedbytheU.S.FishandWildlifeService(USFWS)in1982and1984andthe
OregonDepartmentofGeology andMineralIndustries(DOGAMI)
yearlyfrom1994through1997(DOGAMI1990 to1999).Subsequent BMI
communitysampling
wasconductedbyBLMfrom2000to2008.SeveralfishsamplingeventswereconductedbyBLMandtheOregonDepartmentofFishandWildlife
(ODFW)from1991 through 2007 (BLM2009).
BMIandfishpresence/absencesurveys
wereconductedfortheOU2BERAinMiddleCreekandSouthForkMiddleCreekinJune
andSeptemberof2012andJune andSeptemberof2013.QuantitativeBMI
communitysamplingfromaknown area(144square
inches)wasconductedviaSurbersamplersinrifflehabitatatseverallocations.Fishsurveyswere
conductedusingbackpackelectroshocking,focusing on poolsat
thesamelocations. BMIsampling andfish
surveysfollowedstandardizedprotocolsatallsamplingstationstoallowforcomparisonsof
BMIrelativeabundanceanddiversityandfishpresenceorabsenceasdetailedinthe
OU2 Data Gaps Assessment and Sampling and Analysis Plan Addendum
(CDMSmith2012).BMIsamplesweresubmittedto
theNationalAquaticMonitoringCenterLaboratoryatUtahStateUniversityforenumerationand
identificationtolowestpossibletaxon.
BMIandfishpresence/absencesurveys
wereconductedatthreereferencestreamsinconjunctionwithsamplinginMiddleCreekandSouthForkMiddleCreekinJuneandSeptemberof2012
andJuneandSeptemberof2013. Figures 11a, 11b, and 11c
showtheecologicalsampling locationsin additiontotheMXRand
SFA2sampling locations.Adescription of thehabitat characteristics
ofeach ofthesamplinglocationsis providedinSection2.2.1.1.
1.5 Organization of this ReportSection2servesastheProblem
Formulationsection oftheOU2 BERA.Section3presentsthe
ExposureAssessment,andSection 4presentstheEffectsAssessment.The
informationpresentedin Sections3and 4areintegratedinRisk
Characterization,Section5.Section6presentsthereferences
fortheBERA.TablesandFigures areprovidedfollowing
eachsection,andsupportingdocumentation isprovidedinappendices.
14
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Table 11 Sampling Locations and Dates for Surface Water
Samples
Location Type Oct 2009 Jan/Feb 2010
Oct 2010
Jan 2011
Sep 2011
Feb 2012
Jun 2012
Sep 2012
Jun 20131
Sep 2013
Apr 2014
MIDDLE CREEK Formosa 1 Adit ADIT x x x x x x x x x
A4 STREAM x x x A6 STREAM x
M1.2 STREAM M2.0 STREAM M3.0 STREAM x x x M3.1 STREAM x M5.5
STREAM x M7.9 STREAM x x x M9.8 STREAM M13.0 STREAM x x x MF1 SEEP
x MF2 SEEP x x ME1 STREAM x ME2 SEEP x ME3 SEEP x x MXR STREAM x x
x x x x x x x Seep A STREAM x x MA13 SEEP x MA17 SEEP x x x MA22
SEEP x MA40 SEEP x MA44 SEEP x dry MA46 STREAM x x x x x MA61
STREAM MB1 SEEP x x MB3 SEEP x
Martin Creek Reference STREAM
x
MREF1 STREAM dry x dry x Seep at A9 SEEP x
SOUTH FORK MIDDLE CREEK 404 Adit ADIT x x
404 Adit Lower ADIT SF0.7 STREAM o x SF1.0 STREAM x x x x x x x
x x SF3.0 STREAM x x x SF4.7 STREAM x SFA1 STREAM x SFA2 STREAM x x
x x x x SFA4 SEEP x SFA5 SEEP x SFA8 STREAM x SFB2 STREAM x x SFB4
SEEP x SFB14 STREAM x x x SFD1 SEEP x SFE1 SEEP x SFF1 SEEP x SFG1
SEEP SFG2 STREAM SFG3 STREAM x SFG4 STREAM SFREF1 STREAM x x x
Formosa Mine OU2 BERA 15
-
Table 11 Sampling Locations and Dates for Surface Water
Samples
Location Type Oct 2009 Jan/Feb 2010
Oct 2010
Jan 2011
Sep 2011
Feb 2012
Jun 2012
Sep 2012
Jun 20131
Sep 2013
Apr 2014
RUSSEL CREEK SW3 STREAM x x SW4 STREAM x x SW5 STREAM x x
WEST FORK CANYON CREEK SW6 STREAM x x SW7 STREAM x x C1 STREAM x
x x
COW CREEK CHAMBERS STREAM x x
SW1 STREAM x SW2 STREAM x
RIDDLE INTAKE FAUCET x x x x x x x Notes: Indicates YSI field
parameters only collected at this location x Indicates YSI field
parameters and laboratory sample collection at location BMI and
fish o BMI 1YSI data not reliable for all parameters in June
2013
Formosa Mine OU2 BERA 16
-
West F
orkCa
nyonCreek
Panther Creek
SFF
SFC
SF E
SFB
reek
SFD
SFA
ME
Hunt
erCr
eek
South Fork MiddleCreek
MIDDLE CREEK
MD
SFG
MF
Uppe
r Mid
dle
Cree
k
Brus
hC
reek
Upper
Middle
Crk
Sp
Silve
r But
te
Sp
Hun
ter
Crk
Roseburg Wood Ck
Rus
sellCr
k Rd
Butte
Sp
BrushC
rk
Rd
Middle C
rk S
p
Horse
Heaven
SFork Middle Crk
Pacific
Ocean 21
20
SilverWascoPolk MarionOREGON
Lincoln WheelerJeffersonLinn
Crook Lane Deschutes
22 23 24MREF
")
5 Douglas
Coos
Formosa MineLocation U
Curry Josephine Jackson
")! Lake Klamath
M1.2 Middle C
GF
MXR FORMOSA ADIT M2.0 !!!(((
Raymond Bear Falls
*MXR and SFA2 are flume locations
!!!(((
^G _F Formosa Mine Superfund Site
M3.1 ")FG
GF SF4.7
29 28M3.0 27 SFA2 !!!((( 26
T31S-R06W
SF0.7#*
SF1.0 ")
Sp
33 SF3.0 ")
32 35 34 SFREF
")
LegendEcological Sampling Locations # BMI only* G BMI, FishF "
BMI, Fish, Surface Water) ! Surface Water(
Roads
Hydrology
Contours (100 ft)
Township/Range
Sections
0 0.125 0.25 0.5 Miles
Geographic Data Standards: Projected Coordinate System: NAD 1983
State Plane Oregon FIPS Zone 3602 Data Sources: Bureau of Land
Management: 2001 Hydrography 2005 Township, Range, and
Topography
Figure 1-1a Ecological Sampling Locations
05 T32S-R06W 04 03 02 Formosa Mine Douglas County, Oregon
01
25
36
-
")
GF
")
GF
")
")
#*
")
GF
16
Smith
Creek
Cattle Creek
Hunt
erC
reek
BuckCreek
Panther Creek
Martin Creek
Peavine Creek
Middle Creek
Brus
h Cre
ek
Grav
el Creek
Middle Creek
Buck
Crk S
p
CouncilCrk Rd
Stag T
rl
Stag
Trail
Sp
Cattle
Crk
Sp
QuarrySp
Gra
velC
rk
Gold
Rd
BrushCrk Sp
Sore Foot Rd
Gol
d H
ill
Sp
rk Rd
MartinBuckRd S
Bou
ndar
y Sp
Middle Pea
Middle CkAccess
Cattle/stag
Ced
ar
Gul
ch
PeavineR
d
Peavine
Ceda
r Gulc
h
Sp
Logg
ing
Rd
Hunter
Crk
PantherCrk
SmithCrk
Sp
Logging Rd
Smith
Crk
Cattle Crk
Stag
Trl S
p
Martin Crk
Cattle Ring Mainline
PeavineSp
Audie Crk
Sp
Pacific
Ocean
15 14 13 WascoPolk MarionOREGON
Lincoln WheelerJeffersonLinn
Crook Lane Deschutes
18 17
21 22 5
Douglas
Coos
Formosa MineLocation23 U
Curry Josephine Jackson
")! Lake Klamath24 19 20
G
")
(
F
!
T31S-R07W28 27
T31S-R06W 26 25 30
LegendEcological Sampling Locations
BMI, Fish
BMI, Fish, Surface Water
Surface Water
Roads
Hydrology
Contours (100 ft)
Township/Range
Sections 29
hsur
BC
M5.5 GF
M7.9 ")
M3.1GFSF4.7 GF M3.0
")
33 34 35 36 3231
MartinCreek REF GF
0 0.15 0.3 0.6 Miles
Geographic Data Standards: Projected Coordinate System: NAD 1983
State Plane Oregon FIPS Zone 3602 Data Sources: Bureau of Land
Management: 2001 Hydrography 2005 Township, Range, and
Topography
Figure 1-1b03 T32S-R07W02 01 06 T32S-R06W
05 Ecological Sampling Locations
Formosa Mine Douglas County, Oregon
04
-
GF
GF
GFGF")
")
GF
")
")
#*
")
GF
23
Corral Creek
Short Creek
Hutch Creek
Hare Creek
Cow
Creek
Buck Creek
Stanchion Creek
Calf Creek
Middle Creek
CowCr
ee
k
Buck C
rkSp
Gol
dHi
ll/buc
k CrTie
Stag Trl
Sore
Foot
Rd
Stag
Trail
Sp
Goose Berry Tie
Gol
d H
ill R
d
Cal
f/cor
ral
Gold Hill Jeep Rd
Cor
ralC
rk S
p
Spur
Rd
Susan Ck 101
Middle Ck Ac
cess
Cow
Crk
Acce
ss
Toug
h Cow
Har
e C
rk S
p
Cedar Gulch
Ceda
r Gulc
h
Sp
Susa
nCr
k
Logg
ing
Rd
Cattle/c
alf
Crk
Cor
ral
Crk
Cattle
Crk
Calf Crk
Rocky Mid
dle
Audie Crk S
p
Gold
Hill Sp
Pacific
Ocean
WascoPolk MarionOREGON Lincoln WheelerJefferson
Linn
Crook Lane Deschutes
5 Douglas
Coos
Formosa MineLocation
24 19 20 21 22 U
Curry Josephine Jackson
")! Lake Klamath
25 2930 T31S-R07W 28
G
")
(
F
!
27
LegendEcological Sampling Locations
BMI, Fish
BMI, Fish, Surface Water
Surface Water
Roads
Hydrology
Contours (100 ft)
Township/Range
Sections
T31S-R08W
36 31 M7.9 ")
32 33 34 35
M9.8 GF
01 06T32S-R08W 05 04 T32S-R07W
0 0.15 0.3 0.6 Miles
Geographic Data Standards: Projected Coordinate System: NAD 1983
State Plane Oregon FIPS Zone 3602 Data Sources: Bureau of Land
Management: 2001 Hydrography 2005 Township, Range, and
Topography
Figure 1-1c M13
") Ecological Sampling Locations
02 03
12 07 08 09 10 11 Formosa Mine Douglas County, Oregon
26
-
Section 2 BERA Problem Formulation TheProblemFormulationphaseof
the OU2BERAestablishesthe goalsanddescribesthescopeand focusofthe
assessment.Asdefinedin Section1,OU2 includes all surface water,
sediment, groundwater, undergroundworkings, and adit water drainage
associatedwiththeFormosaMine,whereasOU1
includesthesurfaceandsubsurfaceminewastesand soilsthatweredeposited
outside ofthemineworkings.Thestudy area
forthisBERAforOU2includestheaquaticecosystemspotentiallyaffectedbyMIW,specifically,Middle
CreekandSouth Fork Middle Creek. Based on thefindingsof
theOU1RI(CDM2012),
surfacewaterqualityinbothMiddleCreekandSouthForkMiddleCreekisaffectedbyMIWas
a resultofcontaminanttransportfromtheminewastes andsoilstothese
surfacewaters viaprocessesof directaditdischargestoalluvium,
infiltrationof rainfall, andgroundwater transport. Thisphaseof
theBERA considers
sitespecificregulatoryandpolicyissuesandrequirementsandidentifiespotentialstressors(e.g.,COPCs)andecologicalresourcespotentiallyat
risk.Animportantoutcomeofproblemformulationistheconceptualsitemodel(CSM),whichdescribespotentialexposurescenarios,includingcontaminantsources,transportmechanisms,exposuremedia,exposureroutes,andreceptors.InformationdepictedintheCSMisused
torevealrelationshipsbetweenminerelatedchemicalstressors,
ecologicalreceptors,assessmentendpoints,measurementendpoints,andpreliminaryremedialactionobjectives.Eachofthese
componentsisdefinedanddescribedinthe following
sections.ThesitespecificCSM isdiscussedinSection2.4andpresentedin
Figure 21.
2.1 Stressor Identification Ecologicalstressorsaredefined as
physical,chemical,orbiological entitiesorconditions that
adverselyaffectorhavepotential
toaffectadverselyecologicalreceptorsdirectly orindirectly.This
BERAis focusedonthepotential ecologicaleffectsassociated
withinorganiccompoundsinsurfacewater,based onthefindingsof
theSLERAfortheOU1RI,which identifiedminerelatedstressorsas
inorganicchemicals (cadmium, copper,andzinc) and
possiblyotherminingrelatedstressors suchaspH.
Otherstressors,including
physical(nonchemical)stressorssuchashabitatdisturbanceordegradation,
may contribute to
adverseecologicaleffectswithintheaquaticecosystemsofinterestintheOU2BERA.Habitatdegradationisobservedwheresurfaceand
subsurfaceminewastesandsoilsweredepositedoutsideofthemine
workingsandwithinseepsclosetothemine.One exampleofthis degradation
that is easily
observedisthepresenceofmetalprecipitatesthatcancoversubstrateandnegativelyaffectBMIandother
aquaticorganisms.Asdescribed inSection2.2.1.1,metalprecipitates
havebeenobservedasorange staining andwhiteturbidwaterin
upstreamreachesofMiddleCreekandSouthForkMiddle
Creek,respectively.Thus,habitatdegradationis evidentinthe
aquaticecosystemsofconcernintheOU2BERA.However,thisoccursatonlythemostupstreamecologicalsamplinglocations.
TheeffectofMIWonsurfacewateristhefocusofthe OU2BERA.As
describedinSection2.2.1.2,verylittlefinegrainedsedimentwas
foundduringecologicalinvestigationsfortheOU2BERA, indicating
thatexposuretominerelatedCOPCsinsedimentisnotexpected tobea
significantexposurepathway
21
-
Section 2 BERA Problem Formulation
forBMIor fishthat consumeBMI. Therefore,theabioticmedia of
concernforaquatichabitatsis limitedtosurfacewater. 2.1.1 Chemicals
and Exposure Media of Potential
ConcernTheOU1SLERApreliminarilyidentifiedtheCOPCs,sourceareas,
ecologicalhabitats,andecologicalreceptorsofpotentialconcernconsideredapplicabletotheOU2
BERAfortheaquaticecosystems.
COPCsidentifiedintheSLERAincludecadmium, copper,andzinc.TheseCOPCs
were
identifiedbasedonascreeningofdissolvedconcentrationsofselectedmetals(cadmium,copper,lead,nickel,
andzinc) insurfacewaterintheupperreachesofMiddleCreekandSouth
ForkMiddleCreek. Terrestrialandriparianhabitats
uplandofandadjacenttoMiddleCreekandSouth
ForkMiddleCreekarenotexpectedtobeaffectedadversely
byminerelatedmaterials.AsdescribedintheOU1RI,thesignificantfateandtransportmechanismforCOPCs
fromOU1is transportviagroundwater,which dischargesto
surfacewatersin theupperreaches
ofthecreeks.Terrestrialhabitatsthatwereimpacteddirectlybyminematerials
or have the potentialtobe impactedbyCOPCs via
surfacerunofffromminematerialswere evaluatedas
partofOU1andarenotincludedintheOU2BERA.
AdditionalabioticandbiologicalsamplingandsurveyswereconductedinsupportoftheOU2BERA
tosupplementthispreliminaryinformationandfurther
identifyCOPCsandexposuremedia.Thefindings of ongoing surface
waterandgroundwatersamplingand
ecologicalinvestigationsconductedin2012,2013,and2014wereevaluatedinthe
OU2BERA
torefinethelistofCOPCs.SurfacewateristheexposuremediumofinterestintheOU2BERA.
2.1.2 Refinement of Chemicals of Potential Concern Whilethe
OU1SLERAevaluatedonlyfivemetals(cadmium,copper,lead,nickel,
andzinc), thescreeningevaluationconductedfor
theOU2BERAincludedastandard targetanalyte listof 26metals
(aluminum, antimony,
arsenic,barium,beryllium,cadmium,calcium,chloride,chromium,cobalt,copper,fluoride,iron,lead,magnesium,manganese,
mercury,nickel,potassium,selenium, silver,sodium,
sulfate,thallium,vanadium,and zinc).TheCOPC
screeningprocessforthisBERA includedcomparisonsofmaximumdetected
concentrationsofthesemetals
insurfacewatertoconservativeESLsapplicabletodiverseaquaticlifecommunities(i.e.,BMI,
fish, aquaticplants,andlarvalamphibians). Chemicalsassociated with
maximum
detectedconcentrationsexceedingESLswereretainedasCOPCsfortheOU2BERA.Thisscreeninglevelmethod
isdescribedfurtherinSection3.5.Basedonthisscreening,cadmium,copper,mercury,andzincwereretainedas
COPCsforfurtherevaluationintheOU2BERA. 2.1.3 Summary of Exposure
AreasSurfacewatersofconcerninthe OU2BERAincludeMiddleCreek
andSouthForkMiddleCreek.Eachofthesestreamsis identifiedasseparate
exposureareas(EAs), and each is applicable to
mobileaquaticreceptorssuchasfish thatmovethroughoutthesecreeks.
TheMiddleCreekEAisshownin Figures 11a, 11b,and
11c.TheSouthForkMiddle Creek EA is shown in Figure 11a. Chemical
exposuredata applicabletofish
andothermobileaquaticreceptorsarebasedondatafortheentire
EA(e.g.,mean dissolvedcopper
concentrationsforMiddleCreek).Chemicalexposuredata
fornonmobileorminimallymobilereceptors,suchasBMI,donotutilizeEAsasdescribedabovebutinsteadare
based ondata from unique surface water and biological
samplingstationslocatedoneachof thesecreeks,asdescribedbelow.
22
-
Section 2 BERA Problem Formulation
2.2 Ecological Resources at RiskThefollowing
sectionssummarizeinformationfrom
availabledocumentsofpreviousstudies
intheMiddleCreekwatershedandfromecologicalandhabitatobservationscollectedduring
sampling and reconnaissancesurveysconductedin2012and2013. 2.2.1
Habitats AsdescribedinSection1.4,OU2 ecologicalinvestigationswere
conductedinMiddleCreekandSouth ForkMiddleCreekinJune
andSeptemberof2012andJune andSeptemberof2013. 2.2.1.1 Aquatic
HabitatsMiddleCreekandSouthForkMiddleCreekoriginateasseepsneartheformermining
area.Multiple seepsandtributariescontribute
toeachsurfacewatersystem.
Flumeswithcontinuousautomatedflowmonitoringandwaterchemistryinstrumentationwereinstalledin
or near theheadwatersof bothsystems.Aflume was installedat
MXRforMiddle Creekand atSFA2forSouthForkMiddleCreekto collect data
on flow and water quality and better define seasonalfluctuations
indischargeofcontaminated waters.
AquatichabitatsofinteresttotheOU2BERAincludehighergradient/highenergyreachesofMiddleCreekandSouthForkMiddleCreek
aswellaslower
energyreachesdowngradientoftheformerminingarea.Thesehabitatsincludeperennialinstreamsections
ofthesewaterbodiesaswellasmargins and other areas that may
beonlyintermittentlywet.HabitatobservationsaswellasobservationsoftheBMIcommunitiesandfish
during ecological samplingin2012and2013are describedbelow. Figures
11a, 11b, and 11c showtheecologicalsamplinglocationsinadditionto
the MXR andSFA2 sampling locations. Middle Creek Sampling
LocationsMiddleCreekextendsapproximately13milestoitsconfluencewithCowCreek.
CowCreekisatributarytotheSouthUmpquaRiverthatultimatelybecomesthe
UmpquaRiver,whichreachestheoceanatWinchesterBay.
TheheadwatersofMiddleCreekconsist
ofseveralsmallseepsthatflowdownsteepslopesthroughmature
coniferousforest dominatedby Douglas fir (Pseudotsuga
menziesii).Thesedrainages convergeupstream ofthe MXR sampling
locationwheretheflumeislocatedandcontinuousflowand
waterqualitymonitoringisconducted.MXR
islocatedapproximately0.7milesfrom
theFormosaMineandisasecondorderstream. Thesubstrateat
MXRconsistsoflarge cobble,andpartial armoring (coating and/or
cementingoftherocksbymetalprecipitates)of thesubstratehas
beenobserved.Disturbanceof thesubstrate
duringsomeperiodsoftheyearresultsinmilky,turbidwater.Finegrainsedimentisgenerallylacking.Whilenoecological
sampling has beenconductedatMXR,the BMIcommunity islikely
impaireddue tomine drainage and armoring
ofthesubstrate.Theculvertjustdownstreampresents a
barriertofishaccesstoMXRunder mostif notallflowconditions. TheM1.2
samplinglocationis approximately0.5milesdownstreamofMXR and1.2
milesfromthe mine,asmeasuredfrom thesurfacewaterdrainage headwaters
nearestthemine.This isathirdorderstream witha gradient of about
3%.The substrate consists primarilyof large cobblesandsmall
boulders,withsomearmoringand orangestaining.Thebankfull
widthofMiddleCreekatthislocationisabout12feet,andthebanks
arehighlyincisedinareasalongthisreach.Averagedepthofthestreamisabout0.5feet.Ripariancover
isgood,consistingof redalder(Alnus rubra),vinemaple(Acer
circinatum), andDouglas firwith95%canopycoverage
overthestream.Largewoodydebrisanda
23
-
Section 2 BERA Problem Formulation
fewpoolswith depthsof1 to2 feetarepresent.Finegrained sedimentis
limitedtosmall
amountswithinpoolareas.Duringecologicalsamplingin2012and2013,
veryfewBMIwereobservedatM1.2.Onecutthroattrout(Oncorhynchus
clarkia)wasobservedatM1.2inbothSeptember2012andJune2013,andtwocutthroattroutwere
observedinSeptember2013. TheM2.0 samplinglocationis
approximately0.8milesdownstreamofM1.2and2milesfromthemine.Thisisafourthorderstreamwitha
gradientofabout1.5%.Thesubstrateconsistsprimarilyof cobble.Bankfull
width isaround17feet,withanaveragedepth of0.5feet.Asmallnumberof
1to2footdeeppoolsarepresent.Finegrainedsedimentis generally lacking
butmay bepresentwithin
pools.Analgalmuckwasobservedduringall2012and2013 sampling
events.Attheroad crossing, thereisanapproximately12foot
gapintheriparianvegetation,butelsewhere
thereisagoodripariancorridorconsistingof
redalder,vinemaple,andDouglasfir,providinganaverageof 60%overstream
shade.Duringsamplingin2012and
2013,veryfewBMIwereobserved.Youngofyearsalmonids(notidentifiedtospecies)wereobservedinboth2012
and2013.Roughskinnednewt(Taricha granulosa) andlarval Pacific giant
salamanders (Dicamptodon tenebrosus)werenoted. TheM3.0 sampling
locationis approximately1mile downstreamofM2.0 and3
milesfromthemine.Thisisafourthorderstreamwithagradientaround2.5%.The
averagebankfullwidthis16feet,andaveragedepthis
0.5feet.Thesubstrateconsistsprimarilyof cobblewitha fair amountof
bedrock
present.Finegrainedsedimentislimitedbutmaybepresentwithinshallowpools.
Thereisverygoodripariancover consistingofred alder,vinemaple,and
Douglas fir, providingan averageof95%overstream
shade.TheBMIcommunityappearedgoodduring sampling
in2012and2013.Duringfishsurveysin2012and2013,youngofyearsalmonidswereobserved.Roughskinnednewtand
Pacificgiantsalamanderswerenoted. TheM3.1 samplinglocationis
approximately0.1milesdownstreamofM3.0and3.1
milesfromthemine.ItisjustdownstreamoftheconfluenceofMiddleCreekandSouthForkMiddleCreek.Thisisafifthorderstreamwith
a gradientofabout2%.
Thesubstrateconsistsofcobbleandgravelwithsomebedrock.Orangestainingandmuckymaterial
was
notedonthesubstrateinsomeareas.Finegrainedsedimentisgenerallylacking
but maybepresentwithinpools. Thebankfullwidthisaround 20feet,with
anaverage depthofabout1
foot.Thedominantriparianvegetationconsistsofredalder,willow (Salix
sp.),andDouglasfir,andthereare instreamislandscovered
withgrasses.Overstreamshadeisabout50%. GoodBMI community was
observedduring sampling in2012 and2013.Youngof
yearcutthroattrout,cohosalmon(Oncorhynchus kisutch),
steelhead/rainbow trout(Oncorhynchus mykiss),and sculpin (Cottus
sp.)wereobservedin2012and2013.Inaddition,asteelhead reddwas
observedatM3.1inJune2013. TheM5.5 samplinglocationis
approximately2.4milesdownstreamofM3.1and5.5 milesfromthe
mine.Ecologicalsamplingwasonly conductedatthislocation
inJuneof2012.Thisis afifthorderstream witha gradient around
1.5%.Riparianvegetationisdense,consisting
ofalder,willow,andvinemaplewithinstreamislandscoveredwithgrassesandotheraquaticvegetation.The
bankfull width isapproximately23feet, and average depth is about 1
foot, with 2footpools.Overstream shadecovers
around50%ofthestream.Thesubstrate ispredominantlycobbles with a few
bouldersandsome
bedrockpresent.Finegrainedsedimentisgenerallylacking but may
bepresentwithin pools. TheBMI
communityappearedverygoodduringsamplinginJune2012. Young
oftheyearcohosalmon,
rainbowtrout,sculpin,androughskinnednewtwereobserved. TheM7.9
samplinglocationis approximately2.4milesdownstreamofM5.5and7.9
milesfromthe mine.This isasixthorderstream witha gradient of
approximately 1.5%.Thesubstrateconsistsof
24
-
Section 2 BERA Problem Formulation
cobblesandsomegravel.Bankfull width
isapproximately32feet,andaverage depthisabout 1foot, with pools
upto3feetdeep.Sedimentislimitedbut
maybepresentwithinpools.Riparianvegetationisdenseandconsistsofalderandwillow,
with instreamislandscoveredwithgrassesandother
aquaticvegetation.Canopycovershades around
50%ofthestream.TheBMIcommunityhereappearedverygoodduringsamplinginboth2012and2013.
Young oftheyear coho salmon,cutthroat
trout,andsculpinwereobservedduringsurveys.Beaver(Castor canadensis)
signandroughskinned newtwereobserved. TheM9.8 samplinglocationis
approximately1.9milesdownstreamofM7.9and9.8 milesfromthe
mine.Ecologicalsamplingwasconductedonly
atthislocationinJuneof2012.Thisis asixthorderstream witha gradient
around 2%.Bankfullwidth
isapproximately29feet,andaveragedepthisabout8inches,withpools
upto2.5feetdeep.Thedominantsubstrateisgravel.Sediment
islimitedbutmaybepresentwithinpools.Riparianvegetationisdenseandconsistsofalder
andwillow,
withinstreamislandscoveredwithgrassesandotheraquaticvegetation.Canopycovershadesaround60%ofthestream.TheBMIcommunity
appearedverygoodduring samplinginJune2012.Youngofthe
yearcohosalmonwereobserved alongwithcutthroattroutandsculpin.
Beaversignandroughskinnednewtwereobserved. TheM13
samplinglocationisapproximately3.2miles downstream ofM9.8
and13milesfromthe mine.Ecologicalsamplingwasonly
conductedatthislocation inJune2012.M13
isjustupstreamoftheconfluenceofMiddleCreekandCowCreek.Atthislocation,
MiddleCreekisverywidewithan approximate bankfull width of 44
feet.Atthislocation,thestreamconsistsmostlyofshallowriffle
habitatofaround10 inchesdeepwithsomepools upto3.5 feet
deep.Thisisasixthorderstreamwith a gradientaround1.5%.
Sedimentisgenerallylacking butmay bepresentwithinpools. Theriparian
corridorisdominatedby matureOregonmyrtle(Umbellularia
californica)andOregonash(Fraxinus
latifolia)andshadesapproximately80% ofthestream.The
dominantsubstrateisgravelwithsome cobble.TheBMIcommunity
appearedverygoodduring sampling in June2012. Youngof theyearcoho
salmonwereobservedalongwithrainbowtrout,sculpin,anddace(Rhinichthyssp.).Aroughskinned
newtwasobserved. South Fork Middle Creek Sampling
LocationsSouthForkMiddleCreekbeginsin
aseriesofsmallseeps,includingSFA2,wherea flume
hasbeeninstalledtomeasureflowandwaterqualityparameters.SouthForkMiddleCreekflowsapproximately
5milestoitsconfluencewith MiddleCreek.In
June2012,severallocationsalong
SouthForkMiddleCreekwerevisitedduringtheOU2BERAsitereconnaissance.Locationswereselectedtobeconsistentwith
previoussampling by BLMand others.Thefurthestupstream
locationvisitedonSouthFork MiddleCreekwasSF0.7,located
approximately0.7milesfromtheFormosaMineand0.3milesupstreamofSF1.0,alocationwherewaterqualitysamplingisconductedtwiceperyear.
TheSF0.7 locationisa third orderstreamwitha gradientaround
3%.Thesubstrateconsistsofboulders,cobble,andgravel.Finegrainedsedimentwaslargely
absentduringthesitevisitinJune 2012.Riparianvegetationisdense
andconsistsofDouglasfir, bigleaf maple(Acer
macrophyllum),andvinemapleshading approximately95%ofthestreamandan
understoryofsalal(Gaultheria shallon)andOregongrape (Mahonia
aquifolium). Bankfull widthis6 feet,andaverage depth4inches.During
theJune2012visit,highlyturbid, milky waterwasobserved
whenthesubstratewas disturbed,indicating the presenceofmetal
precipitates.BMIsamplingwas conducted,butno
fishsurveyswereconductedbecauseofthelowwaterlevelandgenerallack
ofsuitable habitat for fish. Ecological
samplingsubsequentlywasnotrepeatedatthislocation.
25
-
Section 2 BERA Problem Formulation
TheSF1.0 sampling locationis approximately1mile
fromtheFormosaMine.Atthis
location,thereisalargepool(aroundthreefeetdeep)downstreamofalarge
culvertunderaroadcrossing.TheSouthForkReferencestream(describedbelow)entersSouthForkMiddleCreekjustdownstreamofSF1.0.TheSF1.0
locationisa fourthorderstream,and thestreamgradient at thislocation
is approximately1.5%.Thedominantsubstrateis
cobble.Theripariancorridorisdenseandconsistsofredalder,bigleafmaple,vinemaple,andDouglasfir,shadingapproximately80%ofthestream.Thebankfullwidth
is approximately 19feet, and average depth is
approximately8inches.Asmallamountoffinegrainedsedimentispresentwithin
pools.Duringsampling in 2012and2013, theBMIcommunity
wassparse.Small numbers(1 or 2)ofcutthroat andrainbowtrout
havebeenobservedduringfish surveys. TheSF3.0 samplinglocationis 2
milesdownstreamofSF1.0and 3milesfrom themine. Thereisa largeculvert
onthedownstreamendthatlikelypreventsfishpassage exceptduring
highflows.Thisis afifthorderstreamwithagradientofapproximately1.5%.
The dominantsubstrateiscobble,withsomesandpresent.Finegrained
sedimentisgenerallylackingbut may bepresentin small amounts
withinpools.Thebankfullwidth isapproximately30 feet,with
anaveragedepthof 0.5feet.Riparianvegetationconsistsofred
alder,bigleaf maple,vine maple,andDouglasfir,withcanopycoverage
around75%. During sampling, theBMI
communityappearedfair.Highernumbersoffish,including cutthroat
andrainbow trout,havebeenobservedduring
fishsurveysascomparedtoSF1.0.Roughskinnednewtshavebeenobserved.
TheSF4.7 samplinglocationis
approximately1.7milesdownstreamofSF3.0and4.7 milesfromthe
mine.Ecologicalsamplingwasonly conductedatthislocation
inJuneof2012.ThislocationisjustupstreamoftheconfluencewithMiddleCreek.Downstreamofthe
confluence,MiddleCreekrunsbyalargegroupcampsite. This
isafifthorderstreamwithagradientofapproximately4%.Dominantsubstrateisbouldersandbedrock,andthereislittle
sediment present.Bankfullwidthis approximately19feet, withanaverage
depth of8inches.Riparianvegetationconsistsofredalder, vinemaple,
willow,and Douglasfir,shading
about60%ofthestream.DuringsamplinginJune2012,theBMIcommunityappearedgood.
Young oftheyearcohosalmon andlarger rainbowtroutwereobserved, along
with Pacific giant salamanders. Reference Sampling
LocationsTheMiddleCreekReferencelocation(MREF)
isonasmalltributarystreamapproximately0.3milesfromitsconfluencewithMiddle
Creek,whichisapproximately0.1
milesdownstreamofM1.2.Atthislocation,thereisa large
culvertlocatedunderaroadcrossing. Thisisa thirdorderstream
withagradientofapproximately1.5%.
Dominantsubstrateiscobble,andthereislimitedsedimentpresent.Theriparianvegetationconsists
ofredalder,vinemaple,and Douglasfir,shading about90%
ofthestream.Bankfullwidthisapproximately6feet,andaveragedepthisabout4inches.Downstreamoftheculvertisapool,about
1.5 feetdeep. Duringsampling,theBMI communityappearedgood.In
Juneof2012,nofishwereobserved,butroughskinnednewtsandaPacific giant
salamander were found.InSeptemberofboth2012 and2013,
thestreamwasnotflowing, sono sampling wasconducted.In
June2013,nofishwereobserved,butsimilar toJune2012,two
roughskinnednewtswerefound along with several young
Pacificgiantsalamanders. TheMartinCreekReferencelocationis
approximately0.3miles upstream along MartinCreekfrom
itsconfluencewithMiddleCreek,whichisapproximately0.5miles
upstreamofM7.9.This isafifthorderstream witha gradient of around
2%.The dominantsubstrate is
cobble,andthereislittlesedimentpresent.Bankfullwidthisaround19feet,andaveragedepthis
about6 inches.Theriparian vegetation
26
-
Section 2 BERA Problem Formulation
consistsofaldersandwillows, providingabout90%overstream
shade.During sampling, theBMI communityappearedverygood.Young
oftheyearcohosalmonand troutfrywereobservedalong with sculpin
andoldercutthroat troutandsteelhead.Pacificgiantsalamanders
wereobserved atthislocation. TheSouthForkMiddleCreekReference
location(SFREF)isapproximately0.7milesupstreamofSF1.0onatributarystreamtoSouthForkMiddle
Creek.Thisis
afourthorderstreamwithagradientofapproximately1.5%.Thereisaroadculvertwithalargepool(about3.25feetdeep)onthedownstreamend.Thedominantsubstrateiscobble.Thereissome
sedimentpresent.Thebankfull widthisabout6feet,with an
averagedepthofabout 0.5feet
outsideofpools.Riparianvegetationconsistsofredalder,vine
maple,andDouglas fir,providing about90%canopycoverage.During
sampling,the BMI communityappeared verygood.Cutthroattrout
(noyoungoftheyear)wereobservedduringfishsurveys. 2.2.1.2 Fate and
Transport within Aquatic HabitatsSurfacewaterqualityinboth
MiddleCreekandSouthForkMiddleCreekisaffectedbyMIW,primarilyfromdischargeatseepsreceiving
contaminants from groundwater.Basedonthe findingsof theOU1 RI(CDM
2012),theprimarymeansoftransportofMIWisvia
alluvialgroundwaterasaresultofleaching and
directdischargefromtheFormosa 1Aditandsubsequentdischargetosurface
waters.DirectrunoffofMIWfromthemine materialswouldonlybe
expectedtooccurafter
intensebutshorttermprecipitationorsnowmeltevents,which occur
primarilyduringlatefallthoughwinter.
Basedonobservationsduringecologicalsamplingin2012and2013,finegrainedsedimentsareminimal
withinbothof
thesesurfacewaterdrainages,particularlyinhighergradientupperreachesandthosedominatedbycobbleandbouldersubstrates.Smallamountsofsedimentarepresentwithinlargerpools,
typicallylocateddownstreamofculverts.Thisindicatesthatsedimenttransportdownstreamisnot
likelya significant means of transport of minerelatedmetals
fromOU1tothe downstreamaquaticsystemsof concernintheOU2BERA.
Inaddition,ecological data
onBMIcommunitiesatseveralsamplinglocationsdescribedaboveare
representativeofrifflehabitats thatare generallylacking in
finegrainedsediment.Sincebenthicmacroinvertebratesinhabittheseareasthatappeartobegenerallylackingfinegrainedsediment,exposuretominerelatedCOPCsin
sedimentisnotexpectedtobe a significantexposure pathway
forbenthicmacroinvertebratesorfishthatconsumeBMI.Therefore,
theabiotic media
ofconcernforaquatichabitatsislimitedtosurfacewater. 2.2.1.3
Terrestrial Habitats UplandUplandvegetationwithin theOU2
BERAstudyareaconsistsprimarilyofconiferousforestdominated byDouglas
fir.Goldenchinkapin(Castanopsis
chrysophylla)andPacificmadrone(Arbutus
menziesii)commonlyoccurindrierareaswhilewesternredcedar(Thuja
plicata)andwesternhemlock(Tsuga
heterophylla)occurinwetterareasoronnorthaspects.Forestageinand
aroundtheminevariesfromoldgrowthstandstoyoungersuccessionalforestandareasofrecenttimberharvest.Openingsinthecanopyallow
forgrowthof
herbaceousvegetation,shrubs,andsaplings.Opendryareasaredominatedby
wedgeleaf ceanothus(Ceanothus cuneatus)andothershrubsas
wellasDouglasfir saplings.Grassesandpoisonoak(Toxicodendron
diversilobum)becomemoreabundantonopen,sunny,southaspectswithinthestudyarea.Wildlife
andplants foundinthestudyarea arelistedin Table 21.
27
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Section 2 BERA Problem Formulation
RiparianRiparianvegetationinandaroundthe OU2BERAstudyarea
isdominatedbydeciduoustreesand shrubs,includingvine
maple,bigleafmaple,andredalder.AlongdownstreamreachesofMiddleCreek,blackcottonwood(Populus
trichocarpa),willow,Oregonash,andOregonmyrtleoccur.Sword
fern(Polystichum munitum)andthimbleberry(Rubus
parviflorus)arecommonunderstoryriparianspecies.Douglas firoccurs
adjacenttostreamsinand aroundthestudyarea.Wildlifeandplantsfound
inthe OU2BERAstudyarea arelistedin attached Table 21.
Terrestrialandriparianhabitatsadjacenttostreams
werecharacterizedusingfieldobservationsand
incorporatingtheuseoftheEcologicalRiskChecklist adapted
fromEPAguidanceforuseonhazardouswastesites.Examplesofcharacteristicsthatwerenotedviaobservationincludedominantplantspeciesinthe
overstory, understory,andgroundcoverwithin theBERAstudyarea
withspecificemphasisonhabitatsadjacentto
thestreams.Theseobservationsareimportantfordocumentingtheterrestrialhabitatsusedbybreedingandnestinganimals,including
listedspecies,within the OU2BERAstudyarea. 2.2.1.4 Fate and
Transport within Terrestrial
HabitatsBasedonobservationsduringecological sampling, the
primarymeansoftransport ofminematerials totheaquaticecosystemsisvia
discharge ofMIW. MIW
istransportedingroundwatertoseepsthatfeedMiddleCreekandSouthForkMiddleCreekandinsurfaceflowsthroughprecipitationonexposedminewastesandmineimpactedsurfacesoils.Theterrestrialhabitatsaffected
byminematerialswereevaluatedintheOU1RI(CDM2012).ThescopeoftheOU2BERA
andmedia evaluatedaredescribed
inSection2.1.1.TheOU2BERAfocusesonassessingriskwithin
aquatichabitats.Riskstoterrestrial
habitatsandreceptorsarenotevaluatedquantitativelyin the OU2BERA.
2.2.2 Ecological ReceptorsFollowing theSLERA from OU1,the
scopeoftheOU2BERAandmediaevaluated
isfocusedonassessingriskwithinaquatichabitats. 2.2.2.1 Aquatic
ReceptorsAquaticreceptorsofinteresttotheOU2BERAincludeaquaticplants,watercolumn
andBMI,fish,and
larvalamphibians.Severalamphibianspecies,includingroughskinnednewtand
Pacificgiant salamander, areknowntooccurin MiddleCreekand
SouthForkMiddleCreekandwereobserved during ecologicalsampling, as
describedabove. Freshwaterfishthatareknownto occur inthe
aquaticecosystemswithintheOU2BERAstudyarea
includecohoorsilversalmonand steelhead/rainbowtrout.Fish
speciesobservedduring fish presence/absencesurveys
conductedin2012and2013includecohosalmon,steelhead/rainbow
trout,cutthroattrout,andsculpin. BothPacificlamprey(Entosphenus
tridentatus)andwesternbrooklamprey(Lampetra
richardsoni)havebeendocumenteddownstreamof thestudyarea at
theODFWsmolttrapinCowCreek(BLM 2002).Threelampreys(speciesnot
identified)wereobservedin MiddleCreekduringpresence/absencesurveys
in1984and1988(Norecol1989).In1993,threelampreys(3to4incheslong)wereobservedinMiddleCreekaboveBrushCreekduringsurveysconductedbyODFW(BLM2002).
28
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Section 2 BERA Problem Formulation
Lampreyswerenotobservedinthe studyareaduringfish
surveyscompletedbyBLMfrom2000to 2007orby EPAin2012and2013. The
nonobservancemaybeattributedtoelectroshockingsamplingtechniquesused,whicharenot
thepreferredmethodforcollecting oridentifying
thepresenceoflampreys.Inaddition,localized
habitatlimitationsorphysicalbarrierstofishpassagemay have
precludedfindinglampreysatthetime ofthesesurveys.
Importantmetricsrelated tofish asreceptorsincludefielddata suchas
numberof fishobservedbyreach, number of fish taxa for a given
reach, and ancillary information,includingnumberof coho
salmonand/orsteelheadreddsper specificstreamreach.Other
importantdata relatedtofishas receptorsincludewaterqualitysuch
aspH,turbidity, anddissolvedmetalsconcentrationsinsurface
water.Metrics suchastheseare
usedtocharacterizecurrentconditionswithrespect
tosuitabilitytosupportfishsurvival,growth,andreproduction.Asubstantial
amountof fish surveyworkhas beenperformedinthestudyareawaters
overthepastseveral decades.TheOU2BERAreliesonthe
resultsoftheseefforts,supplementedby
recentlycollecteddata,tocharacterizethebaselineconditionsofthe
aquaticenvironmentsofinterest. Similarly,benthicinvertebrates serve
asimportantaquaticreceptors,as
waterqualityaffectsBMI,andthereforethesereceptors canbe
usedtoassessphysicalhabitatsuitability,surfacewaterquality,andsedimentquality.Asdiscussedabove,thegeneral
lackoffinegrainedsedimentpresentinthe aquatic
ecosystemswithinthestudyarea
indicatesthatsurfacewaterqualityistheprimaryexposuremedium
forfocusoftheOU2BERA. ManyBMI specieshatchfromeggs laid byadultsin
thesummerandgrowduring thefall, winter,and spring months,emerging
asadultsinlatespring orsummer.Thus,theyareexposed to water quality
conditionsinthestream throughouttheyear.
Inhigherenergyreachesofthestreams(i.e.,riffles),itis
expectedthatdominant BMItypeswouldincludeEPTtaxa(Ephemeroptera
[mayflies],Plecoptera[stoneflies],Trichoptera[caddisflies]).EPTtaxaaregenerallyconsideredsensitivetodissolvedmetals(Maretetal.2003,
Gerhardtetal.2004).Inslower,lowerenergyreachesofthesestreams,itisexpectedthatEPTtaxawillstillbedominantbutofdifferentspecies,withlikelysmallernumbersofnonEPTtaxa
(e.g.,dipterans or fliesandpossiblyworms and snails) comprising the
BMI community. Asforfish, BMImetricsrelatedtoabundanceand
diversityareimportantmetrics for characterizing aquatic
habitatsassuitableorimpaired.BecauseBMI(1)aregenerallynonmobileorhavelimitedmobility;(2)
havelifecyclesthat
generallyspan1to2years;(3)integratephysical,chemical,andbiologicalvariability
overa long timeperiod;and(4)are
intimatelyexposedtobothsurfacewaterandsediment,theyare
excellentindicatorsofwaterand sedimentquality.Asdescribed
inSection2.2.1.2,sedimentexposuresare
notconsideredsignificantbasedonthe general lack
offinegrainedsedimentinprimaryBMI habitat.Much BMI surveywork has
beenperformedinthe studyarea waters overthepast
severaldecades,andtheOU2BERAreliesontheresultsoftheseefforts,
supplementedbyrecentlycollecteddata,tocharacterizethebaselineconditionsoftheaquatic
environmentsofinterest. 2.2.2.2 Terrestrial
ReceptorsTerrestrialreceptorsofinterest
totheOU2BERAincludewildlifethatuseshabitatsdirectlyadjacenttothestreamsandnearbyforest
habitats.Common wildlifewithin theBERAstudyarea
includeseveralspeciesofmammals such as Rooseveltelk(Cervus
canadensis roosevelti),blacktaileddeer(Odocoileus hemionus
columbianus),coyote(Canis latrans),westerngraysquirrel(Sciurus
griseus),andblackbear(Ursus americanus). Commonbirdspeciesfound in
the BERA study area include common raven(Corvus
corax),Stellersjay(Cyanocitta stelleri),mountainquail(Oreortyx
pictus),redbreasted
29
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Section 2 BERA Problem Formulation
nuthatch(Sitta canadensis),blackcappedchickadee(Poecile
atricapillus),bushtit(Psaltriparus minimus),and rufous
hummingbird(Selasphorus rufus). Asdescribedabove,theprimary
meansoftransport ofcontaminantstotheOU2BERA studyarea
isviasurfacewaterandgroundwater,andnotsurfacesoils.
Therefore,theexposurepathwayofinterestforterrestrial
receptorsrelates touseofaquatichabitats(e.g.,drinking
surfacewater,consuming
aquaticbiota).Terrestrialanimals,includingbandtailedpigeon(Patagioenas
fasciata)anddeerhavebeenobserved
drinkingfromtheFormosaadit.However,because
theseterrestrialanimalsaremobile and have large foraging ranges,
theirexposuretocontaminants viadrinkingwaterinMiddle
CreekorSouthForkMiddleCreekis consideredinsignificant. 2.2.2.3
Federally Listed Species Federal Endangered and Threatened
SpeciesThereare11federallythreatened orendangeredspeciesunderthe
jurisdiction oftheUSFWS thathavepotentialtooccur
inDouglasCounty(USFWS2013).Ofthese,sevenare
marinespeciesorassociatedwithcoastalhabitatsnotfoundclosetotheOU2BERAstudyarea.Theremaining
fourspeciesincludetheNorthernspottedowl(Strix occidentalis
caurina)andthreeplants:Gentner's fritillary(Fritillaria
gentneri),Kincaid'slupine (Lupinus sulphureus ssp.
kincaidii),andrough popcornflower(Plagiobothrys
hirtus).Inaddition,threespecies,thefisher(Martes
pennanti),theNorthOregon
Coastdistinctpopulationsegmentofredtreevole (Arborimus
longicaudus), andwhitebarkpine(Pinus
albicaulis)arecandidatesforlisting.A listofthefederallythreatened
andendangeredspeciesisprovidedin Table 22 alongwiththepotentialfor
eachspeciestooccurwithin theBERAstudyarea.Specieswith
highpotentialtooccurareshadedinthe table. TheNationalMarine
FisheriesService(NMFS)liststhreespecies with potential tooccur in
ornear theBERAstudyarea,including Oregon Coast
cohosalmon,greensturgeon (Acipenser
medirostris),andeulachon(Thaleichthys pacificus)(NMFS2013). Federal
Species of ConcernThereareanumberoffederalspecies
ofconcernwithpotential tooccur in ornear theOU2BERAstudyarea
basedontheUSFWSlistforDouglas
County(USFWS2013)andNMFSregionallists(NMFS2013).Speciesofconcernhavea
conservationstatusthatisof concerntotheUSFWSandNMFSbut
forwhichfurtherinformationis
stillneeded.Thesespeciesinclude13birds,9 mammals,7
fish,10reptilesandamphibians,5 invertebrates,
and17plants.Federalspeciesofconcernarelistedin Table 22
alongwiththepotentialforeachspeciestooccurwithinthe
OU2BERAstudyarea.Specieswithhighpotential tooccur areshadedinthe
table. Food Web Model ReceptorsAsdiscussedfurtherinSection
3.6.2,findingsfromtheinvestigations and nature of water
qualitydeterminedthatfoodwebmodelingwasnotnecessaryandwasnot
performed fortheOU2BERA.The COPCsidentifiedfortheOU2BERA
includecadmium,
copper,mercury,andzinc,whichareallbioaccumulativeorpotentiallybioaccumulativechemicals.Cadmium
appearstoaccumulate in lower trophiclevelsbut notin upper
trophiclevelsvia dietaryexposures.
Copperandzincareessentialelementsforlife,andsomeaccumulationisexpected.Onlyatveryhighdosesarecopperandzinctoxictouppertrophiclevelreceptorsvia
diet,yetsuchdosesareunlikelyheregiventheconcentrations
measuredinsurfacewaters
andtheexpectationofinfrequentandshortdurationforagingonsitebyuppertrophiclevelreceptors.
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Section 2 BERA Problem Formulation
Anevaluationofseverallinesof
evidencesupportstheassumptionthatmercuryis
notminerelatedanddoesnotposeaconcernfor
ecologicalreceptorsintheaquaticecosystemsofinterestfortheOU2BERA.TheselinesofevidencearedescribedindetailinSection3.6.2.1.Thelinesofevidenceevaluated
include: Resultsoflowlevelanalysisof
mercuryinupstreamsurfacewaterlocationsclosetothe FormosaMine
Lowfrequencyofdetection(10%)and low
concentrationsinsurfacewatersamples
Comparisontomercuryconcentrationsinotherdrainagesconsideredbackgroundorreference
Informationonhistoricaloperations Limitedfish
tissuesamplingbyODEQ(2004)
Basedontheselinesof evidence,foodwebmodelingassociated
withexposuretomercuryisnotwarrantedfor aquaticreceptors.
2.3 Endpoints and Risk
Questions/HypothesesTheOU2BERAisfocusedonassessingpopulationlevelrisksassociatedwithminerelatedcontaminationin
abiotic media.Ingeneral,risksareassessed
bycomparingCOPCconcentrationsin abioticmedia. Guiding the
estimationofrisksaretwotypesof
endpoints:(1)assessmentendpointsand(2)measurementendpoints.Theseendpointsarediscussedin
Sections2.3.1and2.3.2.
Riskquestionsandhypothesesaredevelopedtotestassumptionsregardingrelationshipsbetweenselectedassessmentendpoints,measurementendpoints,andpotentialexposurestorepresentativereceptors.Theseriskquestions/hypothesesarediscussedinSection
2.3.3. Table 23 relatestheriskquestions/hypothesestoeachassessment
and measurementendpoint. 2.3.1 Objectives and Assessment
EndpointsAssessmentendpointsidentifythe
ecologicalvaluestobeprotected.FortheOU2BERA,abundanceanddiversityofaquaticmacroinvertebratesorfishareimportantassessmentendpoints.Assessmentendpointsareusedin
futurephases,suchastheFS,andintegrated
intoremedialactionobjectives. Appropriate assessmentendpoints
aredevelopedby riskassessorsandoftenconsiderguidancefrom
relevantregulatoryagencies. BERArelated goalsand objectivesinclude:
Reestablishment or maintenance of a balanced and diverse
aquaticecosystem adjacenttoand downstreamoftheFormosa Mine. -
TheaquaticecosystemsofMiddleCreekandSouth
ForkMiddleCreekareadverselyaffectedbyCOPCsreleasedfrom
OU1.Historicalandrecentecologicalinvestigationshaveidentifieda
spatial zoneof impairmentinthesesurfacewaters
thatextendsdownstreamoftheupperreachesevaluatedin theOU1
RI(CDM2012).ThisisdescribedfurtherinSections5.2and5.3.3.
- Thisgoalincludesaspatial
componentwherethezoneofimpairment,ascurrentlyunderstoodfrompreviousinvestigations,
will be
reducedinsizesothatazoneofrecoverybecomesapparentatlocationsclosertothecurrentsourceareasofOU1(i.e.,suitable
211
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Section 2 BERA Problem Formulation
conditionsareextendedupstream).Thezone of impairmentis
definedbyreducedabundanceanddiversityofBMIandotheraquatic
liferelative
toanearbyreferenceareaunimpactedbyminerelatedcontamination.
Reestablishmentofaquaticecosystems
downstreamoftheFormosaMinesuitablefor
supportingallrelevant life stagesofhistoricalsalmonidspecies. -
Similartothe abovegoal,thisgoal includesa
spatialcomponentwherethezone
ofimpairment,ascurrentlyunderstood,willbereducedinsizeso thata
zoneof
recoverybecomesapparentatlocationsclosertothecurrentMIWsource
areas(i.e.,suitableconditionsareextendedupstream).Thezone of
impairmentis definedbyreduced abundanceoffish,
especiallysalmonids,relativetoanearbyreferenceareaunimpactedbyminerelatedcontamination.Achievementofthis
goal may be assessedbymeasuringfishabundanceaswellasincreased
evidence ofreproduction(e.g.,
presenceofyoungoftheyearfish,numberofredds[i.e.,nests])relativetocurrentconditions.
TheOU2BERAisdesignedtosupportdecisionsrelatedtoremedial action
goalsand objectives.
Thissupportconsistsofselectingappropriateassessmentendpoints
andevaluatingrisksrelatedtotheseendpoints.Riskevaluation
andinterpretationisguidedbydevelopmentofspecificriskquestionsor
hypotheses.Thereceptors
andhabitats,contaminantsofconcern,toxicmechanisms,andexposurepathwayswereusedtoselectthe
followingassessmentendpoints. Implicit in theseassessment
endpointstatementsisthe
conceptofensuringthatthesevaluesorresourceswarrantprotectionorshouldbereestablished
or maintained. 2.3.1.1 Surface Water Based Assessment Endpoints
Protectionofaquatic life,including aquaticplants,watercolumnandBMI,
fish,andlarval
amphibians,fromthetoxiceffects,onsurvival,growth,andreproduction,ofCOPCspresentin
surfacewater
Protectionoffishpopulationsandcommunities,especiallysalmonids,
with
potentialtooccurinandinsomecasesreproduceinaquaticenvironmentsofinterest
tothisBERA - Protectindividualsoffederallylistedspecies,including
federallythreatenedOregoncoast cohosalmon
2.3.2 Measurement EndpointsAssessmentendpointsareoftendifficult
tomeasureorevaluate directly.Forexample,itcannotbe
predictedwithcertaintytheconditionsnecessarytoensurethe
survivalandsuccessfulreproductionoffish in
surfacewatersadjacenttoordownstreamofthemine,asthisdependsoninnumerablefactors.However,toxicitydatabased
onexperimentalstudiesorthosedesignatedascriticalthresholdsbyregulatoryagenciesoftencan
helppredictthelikelyoutcomeofexpectedexposures.Measurementendpoints
areforthemostpart TRVsselectedfrom
orbasedonacceptedsourcessuchasEPAandotherrelevantregulatoryagencies.Section4ofthe
OU2 BERA presentsthesurfacewaterspecificTRVs
selectedforestimatingriskstoecologicalreceptors.
Measurementendpointsareused whereassessment
endpointscannotbedirectlymeasuredorevaluated.Measurementendpoints
arequantitativeexpressionsofobservedormeasuredbiologicalresponses
tostressorsrelevantto
selectedassessmentendpoints.Forexample,survival andgrowthof
aquaticinvertebrates(anassessmentendpoint)canbeevaluated using
aquatic toxicitydata basedon
212
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Section 2 BERA Problem Formulation
anappropriatemeasurementendpoint. Asa
morespecificexample,concentrationsofmetalsinsurfacewater
canbecomparedto
concentrationsinlaboratorytestswithsurfacewaterthatresultedinobservedecologicallysignificanteffectstosensitiveandrelevanttestspecies
(i.e.,thewaterflea[Ceriodaphnia
dubia]).Thisexampleexpressestherelationshipbetweenarelevant
measurementendpoint(chroniceffectsconcentration ofmetals in surface
water)thatisdirectlyrelatedtotheassessmentendpointsofaquatic
invertebrate survivalandgrowth.Measurementendpointsselected
fortheOU2BERAincludeinformation from appropriate aquatic
ecotoxicitystudiesandwaterqualitystudiesand,wheredataallow,sitespecificbiologicaldata.
FortheOU2BERA,ecologicallysignificanteffectsaredefined as
thoseaffecting survival,growth, orreproduction
ofselectedreceptors.Otherendpoints,suchaseffectsonbehavior
orhistopathologicaleffects,are notconsideredbecausethesecannot
beeasilylinkedtoecologically significantendpoints that can impair
populations or communities.Protectionof
populationsandcommunitiesisamajorgoal oftheOU2BERA
whileprotectionofindividual organismsiswarrantedforfederallylisted
speciesandspeciesofconcern. 2.3.3 Risk
Questions/HypothesesHypothesesorriskquestionsareusedtotestassumptionsregardingrelationshipsbetweenselectedassessmentendpoints,measurementendpoints,and
potential
exposuresforselectedrepresentativereceptors.ThehypothesesidentifiedfortheOU2BERAarebased
ontheselectedecologicalreceptors andthemajorexposure
scenarioslinked to thesereceptors.Somereceptorgroups,although
consideredimportant,arenotincluded
inthefollowinghypothesesbecauseassessmentdataare sparseorlacking.
Forexample, protectionof
localamphibianpopulationsisconsideredimportant,butdataarelackingtoassessthepotentialimpactsonthesereceptors.Agoalofthe
OU2BERAis toanswerthefollowingriskquestionswithsufficient
confidence toallow appropriatedecisionmaking
withregardtoremediation. BenthicMacroinvertebrates
Arethelevelsofcontaminantsinsurface
watergreaterthanthesurfacewaterTRVsor
surrogatevaluesforthesurvival,growth,orreproductionof BMI? -
Datatosupportaresponsetothis questioninclude COPC as
dissolvedconcentrationsinsurfacewater thatarehardness adjusted, as
applicable, from
multiplelocationsimmediatelydowngradientfromtheFormosaMineSite,wherehabitatsarenonsupportiveofBMI,todownstreamlocationswhereBMIhabitatshaverecoveredtonearreferenceconditions.
Isthestructure(basedprimarily
onabundanceanddiversity)ofBMIcommunitiessignificantlydifferentfromreferencelocations?
- Datatosupportaresponsetothis questioninclude historical
andrecentBMIsurveysconductedfortheOU2BERA,emphasizingmeasurementofmetrics
relatedtoabundanceanddiversityfromlocationsincludingreferenceandpotentiallyimpairedreflectingconditionsbetweenhighlyimpaired(i.e.,currentlynonsupportiveofBMI)andreference.
AquaticLife(General)
Aretheconcentrationsofdissolvedcontaminantsin surfacewater within
theaquatic ecosystemsofOU2greater
thanthesurfacewaterTRVs(dissolved) forthesurvival,growth,
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Section 2 BERA Problem Formulation
andreproductionof aquatic life, including
aquaticplants,watercolumn andBMI, fish, and larval amphibians? -
Datatosupportaresponsetothis questioninclude COPC as
dissolvedconcentrationsinsurfacewater thatarehardness adjusted, as
applicable, from multiplelocationsimmediately
downgradientfromtheFormosaMineSite,wherehabitatsarenonsupportiveofaquaticlife,todownstream
locationswhereaquatichabitats haverecovered
tonearreferenceconditions.
Fish Aretheconcentrationsofdissolvedcontaminantsin surfacewater
greaterthanthedissolved surfacewater TRVsforthesurvival,growth,and
reproductionof fish,witha focuson salmonid fish? -
Datatosupportaresponsetothis questioninclude COPC as
dissolvedconcentrationsinsurfacewater thatarehardness adjusted, as
applicable, from
multiplelocationsimmediatelydowngradientfromtheFormosaMineSite,wherehabitatsarenonsupportiveoffish,towherepotentialfish
habitatshaveapparentlyrecovered tonearreference conditions.
Isthereadifferenceinfishpresence/absenceinsurfacewatersaffectedbyMIWcompared
toreferenceareas? - Datatosupportaresponsetothisquestioninclude
fishsurveysemphasizingpresence/absenceandgeneralnumbersandtypesofspeciesrelativetoreference.ReferenceisdefinedhereaslocationsdownstreamofOU1where
abundanceanddiversityoffishapproachvaluesexpected
fornonimpairedwatersinthisregion.Surveylocations
encompassareasofsevere impairment(i.e.,upstreamlocations
currentlynonsupportiveoffish)andreferenceareas. Multiple
locationswithintheseboundariesweresurveyedtoprovidecharacterizationofthe
currenttransitionalzonebetweensevereimpairmentandrecovery.Samplinglocations,methods,and,totheextentpossible,agencies/firms/staffusedinprevioussurveyswereconsistenttoallowforcomparabilityovertime
(notethatadversesituationsrelatedtoattainmentofcollection permits
were minimizedusingthisapproach).
Table 23 summarizesthe
relationshipbetweenassessmentendpoints,representativereceptorspecies,measurementendpoints,andthe
associatedriskquestions(i.e.,testablehypotheses).
2.4 Conceptual Site ModelTheCSMfor theOU2BERA(Figure 21) isa
visualpresentationthatsummarizeskeycomponents
relatedtopotentialecologicalexposures resultingfromsiterelated
chemical contamination.The CSM istheprimaryoutputofthe
ProblemFormulation
phaseoftheecologicalriskassessment.Itsummarizesexposurescenariosand
isusedtohelpdevelopaseriesoftestablenullhypotheses,aspresentedinthissection.Inaddition,theCSM
is
usedtosupporttheselectionofappropriateassessmentandmeasurementendpoints.
TheCSMpresentsthepotentialexposurepathwaysforrepresentativeecologicalreceptorsexposedtominerelatedcontaminants.Tobe
comprehensive, theCSMincludeshumanhealth
exposurepathwaysalthoughtheyarenotdiscussed furtherin
theOU2BERA.These potentialpathwaysindicatehowthe
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Section 2 BERA Problem Formulation
ecologicalresourcescancooccurorcomeincontactwithcontaminantsandincludecontaminant
sources, fate and transport processes,andexposureroutes.
FortheOU2BERA, Figure 21 presents
allthecomponentsoftheCSM.Includedonthisfigurearesymbolsrepresentingvariousassumptionsaboutexposurepathways.Solidcirclesrepresentcompleteandsignificantexposurepathwaysthatare
evaluated
quantitatively.Opencirclesrepresentincompleteexposurepathways.Blacktrianglesrepresentexposurepathwaysthatareconsideredoneofthefollowing:
Insignificant andcomplete(subjecttoqualitativeevaluationwhere data
allow) Insignificantandcomplete(but notevaluatedduetolackofdata)
Potentiallycompletebutinsignificantor highly unlikely in
mostcases
Quantitativeriskestimationin
theOU2BERAisreservedforthefollowing:
Aquaticbenthicinvertebratesbasedoninstreamsurfacewaterexposures
Fishandwatercolumninvertebratesand,toalesserextent,aquaticplantsandlarval
amphibiansbasedonsurfacewaterexposures
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Table 21 Wildlife and Plants Found at the Formosa Mine OU2 and
Vicinity Douglas County, Oregon
Scientific Name Observed? Notes*
Birds Bandtailed pigeon Patagioenas fasciata Yes Blackcapped
chickadee Poecile atricapilla Yes Bushtit Psaltriparus minimus Yes
Common raven Corvus corax Yes Greathorned owl Bubo virginianus
heard only Mountain quail Oreortyx pictus Yes Northern Spotted Owl
Strix occidentalis caurina No Likely to occur Redbreasted nuthatch
Sitta canadensis Yes Redtailed hawk Buteo jamaicensis Yes Rufous
hummingbird Selaphorus rufus Yes Steller's jay Cyanocitta stelleri
Yes Turkey vulture Cathartes aura Yes Violetgreen swallow
Tachycineta thalassina Yes Western screetch owl Megascops
kennicotti Yes Wrentit Chamaea fasciata heard only Mammals
American black bear Ursus americanus Yes Bobcat Lynx rufus sign
Coyote Canis latrans sign Mountain lion Felis concolor No Likely to
occur in low numbers Mule (blacktailed) deer Odocoileus hemionus
Yes Roosevelt elk Cervus canadensis roosevelti Yes Western gray
squirrel Sciurus griseus Yes Woodrat Neotoma sp. Yes Fish
Black crappie Pomoxis nigromaculatus No Likely to occur in lower
watershed Bluegill Lepomis macrochirus No Likely to occur in lower
watershed Brown bullhead Ameiurus nebulosus No Likely to occur in
lower watershed Chinook salmon Oncorhynchus tshawytscha No Likely
to occur in lower watershed Coarsescale sucker Catostomus
macrocheilus No Likely to occur in lower watershed Coho salmon
Oncorhynchus kisutch Yes Cutthroat trout Oncorhynchus clarki Yes
Longnose dace Rhinichthys cataractae dulcis No Likely to occur in
lower watershed Pacific lamprey Lampetra tridentata No Likely to
occur in lower watershed Rainbow trout Oncorhynchus mykiss Yes
Redside shiner Richardsonius balteatus hydrophlox No Likely to
occur in lower watershed River lamprey Lampetra ayresi No Likely to
occur in lower watershed Salmon Unknown Yes
Sculpin Cottus spp. Yes Smallmouth bass Micropterus dolomieu No
Likely to occur in lower watershed Speckled dace Rhinichthys
osculus No Likely to occur in lower watershed Umpqua pikeminnow
Ptychocheilus oregonensis No Likely to occur in lower watershed
Formosa Mine OU2 BERA 217
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Table 21 Wildlife and Plants Found at the Formosa Mine OU2 and
Vicinity Douglas County, Oregon
Scientific Name Observed? Notes*
Reptiles and Amphibians
Common garter snake Thamnophis sirtalis Yes Pacific giant
salamander Dicamptodon ensatus Yes Pacific chorus (tree) frog
Pseudacris regilla No Likely to occur Roughskinned newt Taricha
granulosa Yes Rubber boa Charina bottae Yes Western fence lizard
Sceloporus occidentalis Yes Western skink Eumeces skiltonianus Yes
Hibernaculum found during sampling Invertebrates Benthic
invertebrates Multiple Taxa Yes
Ground beetle Family Carabidae Yes
Lorquin's admiral butterfly Limenitis lorquini Yes Water
striders (skimmers) Family Gerridae Yes
Yellowspotted millipede Harpaphe haydeniana Yes Trees
Bigleaf maple Acer macrophyllum Yes
Black cottonwood Populus trichocarpa Yes California black oak
Quercus kelloggii Yes Canyon live oak Quercus chrysolepis Yes
Douglasfir Pseudotsuga menziesii Yes Golden chinkapin Chrysolepis
chrysophylla Yes Incense cedar Calocedrus decurrens Yes Jeffrey
pine Pinus jeffreyi Yes Oregon ash Fraxinus latifolia Yes Oregon
myrtle Umbellularia californica Yes Oregon white oak Quercus
garryana Yes Pacific madrone Arbutus menziesii Yes Ponderosa pine
Pinus ponderosa Yes Red alder Alnus rubra Yes Sugar pine Pinus
lambertiana Yes Tan oak Lithocarpus densiflorus Yes Vine maple Acer
circinatum Yes Western hemlock Tsuga heterophylla Yes Western
redcedar Thuja plicata Yes Willow Salix sp. Yes Shrubs
Manzanita Arctostaphylos sp. Yes Oregon grape Mahonia aquifolium
Yes Western poison oak Toxicodendron diversilobum Yes Salal
Gaultheria shallon Yes Western sword fern Polystichum munitum Yes
Thimbleberry Rubus parviflorus Yes Wedgeleaf ceanothus Ceanothus
cuneatus Yes
*Likely to occur based on habitat and range.
Formosa Mine OU2 BERA 218
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Table 22 Federally Listed, Candidate Species, and Species of
Concern and Potential to Occur at the Formosa Mine OU2 and Vicinity
Douglas County, Oregon Common Name Scientific Name Listing Status
Potential to Occur1
Birds
Acorn woodpecker Melanerpes formicivorus SC Low American
Peregrine falcon Falco peregrinus anatum DL Low Bald eagle
Haliaeetus leucocephalus DL Low Bandtailed pigeon Patagioenas
fasciata SC High Black oystercatcher Haematopus bachmani SC None
Brown pelican Pelecanus occidentalis DL None Harlequin duck
Histrionicus histrionicus SC Low Lewis' woodpecker Melanerpes lewis
SC Low Marbled murrelet Brachyramphus marmoratus CH FT Low Mountain
quail Oreortyx pictus SC High Northern goshawk Accipiter gentilis
SC Moderate Northern spotted owl Strix occidentalis caurina CH FT
High Olivesided flycatcher Contopus cooperi SC Moderate Oregon
vesper sparrow Pooecetes gramineus affinis SC Low Purple martin
Progne subis SC Low Shorttailed albatross Phoebastria albatrus FE
None Western burrowing owl Athene cunicularia hypugaea SC None
Western snowy (coastal) plover Charadrius alexandrinus nivosus CH
FT None Whiteheaded woodpecker Picoides albolarvatus SC Low
Yellowbreasted chat Icteria virens SC Low Mammals
Fisher Martes pennanti Candidate Moderate Fringed myotis bat
Myotis thysanodes SC Moderate Longeared myotis bat Myotis evotis SC
Moderate Longlegged myotis bat Myotis volans SC Moderate Pallid bat
Antrozous pallidus pacificus SC Low Red tree vole Arborimus
longicaudus Candidate Moderate Silverhaired bat Lasionycteris
noctivagans SC Moderate Smallfooted myotis bat Myotis ciliolabrum
SC Moderate Townsend's western bigeared bat Corynorhinus townsendii
townsendii SC Moderate Whitefooted vole Arborimus albipes SC
Moderate Yuma myotis bat Myotis yumanensis SC Moderate Fish
Coasta