southern cove orrington remediation site orrington, … · sediment chemical characterization ......

Mallinckrodt US LLC

June 8, 2016

CORRECTIVE MEASURES IMPLEMENTATION PLAN

Southern CoveOrrington Remediation Site

Orrington, Maine

Prepared by:

Anchor QEA, LLC

9 Water Street, First Floor

Amesbury, MA 01913

CDM Smith, Inc.

25 Industrial Avenue

Chelmsford, MA 01824

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Table of Contents

Section1. Introduction....................................................................................................................................1‐1

Purpose........................................................................................................................................................................1‐1

SiteDescription........................................................................................................................................................1‐1

ReportOrganization..............................................................................................................................................1‐1

Section2. SummaryofSouthernCovePre‐designActivities...............................................................2‐1

Background................................................................................................................................................................2‐1

Pre‐designActivitiesOverview........................................................................................................................2‐1

BathymetricSurvey...............................................................................................................................................2‐1

HydrodynamicStudy.............................................................................................................................................2‐2

GeotechnicalInvestigation.................................................................................................................................2‐2

DisposalCharacterization...................................................................................................................................2‐3

TreatabilityTesting................................................................................................................................................2‐4

SedimentChemicalCharacterization.............................................................................................................2‐4

IntertidalVegetationSurvey..............................................................................................................................2‐4

Section3. DesignObjectives...........................................................................................................................3‐1

CorrectiveMeasuresImplementationPlanObjectives..........................................................................3‐1

MediaProtectionStandards...............................................................................................................................3‐1

CompliancewiththeOrderMediaProtectionStandards.....................................................................3‐1

SouthernSedimentRemovalArea(SMA‐3..................................................................................................3‐3

SoutherlyStreamSedimentRemovalArea(SMA‐1)...............................................................................3‐5

NorthernSedimentRemovalArea(SMA‐2)................................................................................................3‐6

NorthernSedimentRemovalArea(SMA‐2)–NorthernPortion........................................3‐6 NorthernSedimentRemovalArea(SMA‐2)–SouthernPortion........................................3‐7 NorthernSedimentRemovalArea(SMA‐2)–WesternEdge...............................................3‐7

DefinitionofPreliminarySedimentRemovalAreas...............................................................................3‐7

Section4. SouthernCoveCorrectiveMeasuresImplementationActivities....................................4‐1

OverviewoftheRemedialAction....................................................................................................................4‐1

ExistingConditionsandSitePreparation....................................................................................................4‐1

SiteTrailers/Offices................................................................................................................................4‐1 SiteStaging..................................................................................................................................................4‐1 SedimentProcessingandStockpilingAreas................................................................................4‐1 AccessRoads..............................................................................................................................................4‐2 TemporaryErosionandSedimentControl...................................................................................4‐2

SedimentRemovalandProcessingActivities............................................................................................4‐2

Excavation...................................................................................................................................................4‐2 Dredging.......................................................................................................................................................4‐3 DredgedMaterialProcessing..............................................................................................................4‐3

Table of Contents Corrective Measures Implementation Plan

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EnvironmentalControls.......................................................................................................................................4‐4

WaterQualityandFishMonitoring.................................................................................................4‐4 WaterTreatment......................................................................................................................................4‐4

RestorationActivities............................................................................................................................................4‐5

Backfilling....................................................................................................................................................4‐5 PlantingandSeeding..............................................................................................................................4‐5

Section5. Permitting........................................................................................................................................5‐1

Section6. Schedule............................................................................................................................................6‐1

Section7. References........................................................................................................................................7‐1

List of Tables

Table2‐1:FlowVelocitySummary–MaximumsMeasuredNeartheSouthernCoveOvera12‐hourTidalCycleonAugust3,2016.....................................................................................2‐2

Table6‐1:ProposedSouthernCoveSchedule..............................................................................................6‐1

List of Figures

Figure1‐1:SiteMap

Figure1‐2:SedimentSampleLocations

Figure2‐1:SedimentRemovalAreasandDepths

Figure2‐2:ExtentofIntertidalVegetation

Appendices

AppendixA:Pre‐designActivitiesReport

AttachmentA.1:BathymetricReport

AttachmentA.2:AcousticDopplerCurrentProfilerReport

AttachmentA.3:BoringLogs

AttachmentA.4:GeotechnicalData

AttachmentA.5:TreatabilityReport

AttachmentA.6:MercuryDataReport

AttachmentA.7:DataUsabilityAssessment

AppendixB:TurbidityControlEvaluationReportAppendixC:DelineationofSedimentRemovalAreasforBasisofRemedialDesignTechnicalMemorandum

Table of Contents Corrective Measures Implementation Plan

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AppendixD:WaterQualityandFishMonitoringPlanAppendixE:DrawingsAppendixF:TechnicalSpecificationsAppendixG:ConstructionQualityAssurancePlanAppendixH:RemediationContractorHealthandSafetyPlan(placeholder,tobeprovidedbycontractor)AppendixI:Schedule(placeholder,tobeprovidedbycontractor)

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Acronyms

ADCP AcousticDopplerCurrentProfilerbgs belowgroundsurface

CEO CodeEnforcementOfficerCMI CorrectiveMeasuresImplementationCMS CorrectiveMeasuresStudyCQA ConstructionQualityControlCU CertificationUnitCWA CleanWaterActcy cubicyardDelineationTechnical ProposedDelineationofSedimentRemovalAreasforBasisMemorandum ofRemedialDesignEPA U.S.EnvironmentalProtectionAgency

ft/s footpersecondMaineBEP StateofMaineBoardofEnvironmentalProtectionMallinckrodt MallinckrodtUSLLCMaineDEP MaineDepartmentofEnvironmentalProtectionMEPDES MainePollutantDischargeEliminationSystem

mg/kg milligramsperkilogram

MPS MediaProtectionStandardNTU nephelometricturbidityunit

Order MaineBEPOrderdatedAugust19,2010,andeffectiveApril3,2014,whichincorporates,withmodifications,theComplianceOrderissuedbyMaineDEPdatedNovember24,2008

PERC PenobscotEnergyRecoveryCompany

RCRA ResourceConservationandRecoveryAct

RPM RemediationProjectManagerSI SiteInvestigationSIReport SiteInvestigationReportSMA SedimentManagementAreaTCLP ToxicityCharacteristicLeachingProcedureTESC temporaryerosionandsedimentcontrolTSS totalsuspendedsolids

TSSA‐2 TemporarySoilStockpileArea#2

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Section 1. Introduction

Purpose This Southern Cove Corrective Measures Implementation Plan (CMI Plan) was prepared byAnchorQEA,LLC,andCDMSmith,Inc.,onbehalfofMallinckrodtUSLLC(Mallinckrodt).Thepurposeofthis CMI Plan is to present the corrective measures necessary to remediate sediment within theSouthern Cove of the Penobscot River adjacent to the Orrington Remediation Site located at99IndustrialWay,Orrington,Maine,showninFigure1‐1.TheCMIPlanpresentstheobjectivesofthecorrectivemeasures,resultsofthepre‐designactivities,designdrawings,andtechnicalspecificationstoimplementtheremedialaction.

PlansandengineeringdesignsfortheSouthernCoveremediationweredevelopedinaccordancewiththeStateofMaineBoardofEnvironmentalProtection(MaineBEP)OrderdatedAugust19,2010,andeffectiveApril3, 2014,which incorporates,withmodifications, theComplianceOrder issuedby theMaineDepartmentofEnvironmentalProtection(MaineDEP)datedNovember24,2008(collectivelyreferredhereafterasthe“Order”).TheOrderrequirescorrectivemeasurestoachieveMediaProtectionStandards(MPSs)formercuryinsediment.

Site Description The Southern Cove is located in the Penobscot River bordering the Orrington Remediation Site, asshowninFigure1‐1.Afulldescriptionofthesite,whichincludedaformermanufacturingplantandfive landfills, is included in the Site InvestigationReport (SI Report; CDM 1998) and theCorrectiveMeasuresStudy(CDM2003).TheSouthernCoveliestothesouthofthehistoricalmanufacturingplantarea,ontheeasternsideofthemainchannelofthePenobscotRiver.ThePenobscotRiverissubjecttotidal fluctuations up to 16 feet, and a portion of the cove is tidalmudflats exposed under low tideconditions.

TwooutfallsandtwodrainagesthatcurrentlydischargetotheSouthernCoveareshowninFigure1‐2.Oneof the twooutfalls is thepermittedeffluentpipe fromtheon‐sitegroundwater treatmentplant(GWTP),whichrunsbeneaththebeachatthenorthernsideofthecoveanddischargesintotheriver.Theotheroutfall isthecoolingwaterdischargepipefromthePenobscotEnergyRecoveryCompany(PERC)facility;thepipeisburiedbeneaththebeachandrunsoffshorenearthecentralportionoftheSouthernCove.The twodrainages that flow into the cove are theNorthernDrainageDitch and theSoutherlyStream.

Report Organization Thereportisorganizedasfollows:

Section1:Introduction

Section2:SummaryoftheSouthernCovePre‐designActivities

Section3:DesignObjectives

Section4:SouthernCoveCorrectiveMeasuresImplementationActivities

Section5:Permitting

Section6:Schedule

Section7:References

Thefollowingtechnicalappendices(AthroughI)arealsoincludedandreferencedinthesesections:

Section 1 Introduction

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AppendixA:Pre‐designActivitiesReport

AttachmentA.1:BathymetricReport

AttachmentA.2:AcousticDopplerCurrentProfilerReport

AttachmentA.3:BoringLogs

AttachmentA.4:GeotechnicalData

AttachmentA.5:TreatabilityReport

AttachmentA.6:MercuryDataReport

AttachmentA.7:DataUsabilityAssessment

AppendixB:TurbidityControlEvaluationReport

AppendixC:DelineationofSedimentRemovalAreasforBasisofRemedialDesignTechnicalMemorandum

AppendixD:WaterQualityandFishMonitoringPlan

AppendixE:Drawings

AppendixF:TechnicalSpecifications

AppendixG:ConstructionQualityAssurancePlan

AppendixH:RemediationContractorHealthandSafetyPlan(placeholder,tobeprovidedbycontractor)

AppendixI:Schedule(placeholder,tobeprovidedbycontractor)

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Section 2. Summary of Southern Cove Pre‐design Activities

Background The Orrington Remediation Site, including the Southern Cove, was investigated during the SiteInvestigation(SI;CDM1998)andCMS(CDM2003).Atotalof250sedimentsampleswerecollectedfrom the SouthernCove and analyzed formercury,with some samples also analyzed for additionalphysicalparameters.ThemajorityofthesesampleswerecollectedandreportedaspartoftheSIReportandCMS,whichwerereviewedbyMaineDEPandtheMaineBEPandformedthebasisoftheirfinaldecisionsontheremedialactionsrequiredfortheSouthernCoveintheOrder.

AdditionaldatawerecollectedfromtheSouthernCoveduringthepre‐designfieldactivitiesconductedin2015and2016.Afullreportofthepre‐designmethodsandresultsisincludedinAppendixA.Resultsarealsobrieflysummarizedinthefollowingsubsections.

Pre‐design Activities Overview Pre‐design field work was completed in accordance with the Maine DEP‐approved Southern CovePre‐design Work Plan (AnchorQEA and CDM 2015). Subsequent work plan modifications wererequestedduringthefieldactivitiesandapprovedbyMaineDEP, includinge‐mails fromMaineDEPdatedMay21,2015regardingdrillingequipmentandoceanographicsurveytimeintervals,andJune12, 2015 regarding sampling sediment for chloropicrin. In addition, a work plan addendum wasapprovedbye‐mailfromMaineDEPonSeptember4,2015.

Fieldworkwascompletedduringlatespringandfall2015.WorkwascompletedinaccordancewiththeQualityAssuranceProjectPlan (CDM Smith 2014a), theProjectHealth and SafetyPlan (CDM Smith2014b), and theHealthandSafetyPlan (AnchorQEA2014) prepared specifically for remedial datacollectionactivitiesintheSouthernCove.

Field data collection and laboratory analyses conducted as part of the pre‐design field activitiesincluded:

Bathymetricsurvey

Hydrodynamicstudy(includingAcousticDopplerCurrentProfiler[ADCP]surveyandtidegaging)

Geotechnicalinvestigations

Disposalcharacterization

Treatabilitytesting

Sedimentchemicalcharacterization

Intertidalvegetationsurvey

Areportofpre‐designworkisincludedinAppendixAandsummariesareprovidedinsubsequentsections.

Bathymetric Survey AbathymetricsurveyoftheSouthernCoveuptothemaximumhightidelinewasconductedin2015andisdepictedinthePre‐designActivitiesReport(AppendixA;Figure2‐1).

Section 2 Summary of Southern Cove Pre‐design Activities

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Hydrodynamic Study Ahydrodynamicstudywasconductedtoevaluatetherangeofexpectedtidalfluctuationandcurrentvelocities,and toprovidedata forhydrodynamicanalyses tosupport thedesignof turbiditycontrolmeasures.AtemporarytidalgagewasinstalledintheSouthernCovetomeasurewaterlevelsovertidalcyclesbetweenJune15and20,2015.Tidalfluctuationswereapproximately15feet.

WaterflowvelocitiesacrossthePenobscotRiverchanneladjacenttotheSouthernCoveweremeasuredduring an ADCP survey in June 2015. Flow velocities measured at the surface and the average ofvelocitiesmeasuredat0.25‐footdepth intervals throughthewatercolumnwereevaluated.Velocitydatawere collectedhourly over the studyperiod.Table2‐1 lists themaximumsurface anddepth‐averagedvelocitiesfortheupstream,middle,anddownstreamlocationsduringthefloodandebbtidesmeasuredinthevicinityoftheSouthernCovesedimentremovalareas.

Table 2‐1: Flow Velocity Summary – Maximums Measured Near the Southern Cove Over a 12‐hour Tidal Cycle on August 3, 2016

ADCP Transect

Flood Tide Ebb Tide

Surface Velocity (ft/s)

Depth‐averaged Velocity (ft/s)

Surface Velocity (ft/s)

Depth‐averaged Velocity (ft/s)

Upstream Transect 3.5 2.6 3.2 2.7 Middle Transect 2.9 2.3 3.5 2.8

Downstream Transect 2.8 2.1 3.2 3.1

Note: ft/s = feet per second

Basedonreviewofcollectedfielddataandpublishedtidalandcurrentdata,ahydrodynamicevaluation,includingmodelingoffloodandebbconditionsandflowrates,wascompletedandresultsareincludedinAppendixB.The resultswereused to evaluate loadings from flows in the riveronpotential siltcurtain designs/orientations. Based on this analysis, a mobile turbidity curtain system is beingrecommended rather than larger, stationery silt curtains, which may not be stable in high flowconditions.

Geotechnical Investigation Geotechnicaldatawerecollectedtosupportengineeringdesignwiththefollowingobjectives.SamplelocationsareshowninFigure1‐2.

Collectstandardpenetrationtestdatatoevaluatethedepthtocompetentstrataandtodeterminethetypeanddesignoffootingsifrequiredforasiltcurtain

Sampledatawerecollectedoutsidethesedimentremovalareas,nearoratthebreakbetweentheSouthernCoveandtheedgeofthePenobscotRiverChannelatSD‐SC‐01,‐02,and‐03

CollectstandardpenetrationtestandgrainsizedatatosupportdesignofanequipmentaccessroadacrosstheintertidalareaoftheSouthernCove,ifneeded

SampledatawerecollectedwithintheintertidalareaatlocationsSD‐SC‐04,‐05,and‐06

Characterizephysicalpropertiesofsedimenttoberemovedandstratigraphytosupportengineeringforthesedimentremovaldesign


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Datawerecollectedfromalllocationssampledduringthepre‐designinvestigation

Subsurface sampling conditions were difficult, with frequent refusals encountered. Both vibracore(4‐inchdiameter)andsplit‐spoon(2‐or3‐inchdiameter)sampling techniqueswereemployed,andbothsampling techniquesmetwithrefusalbetween1and2 feetatmanyof thesampling locations.DetailsonthetechniquesusedatspecificsamplinglocationsareavailableintheboringlogsincludedinthePre‐designActivitiesReportinAppendixA.

Overall,basedonfieldobservationsandgeotechnicalanalyses,materialwithinthesedimentremovalareasisgenerallycharacterizedaswellgraded,rangingfromcobblestoclay,withmediumtocoarsesand as the dominant grain sizes. Sediment is finest in the southern sections of the cove where adiscontinuoussoftsiltlayeroccurswithinthetop1to2feetbelowthemudline.Thissurfacesiltlayerisgenerallyabsenttowardthenorth(SD‐SC‐07)andtowardthePenobscotRiverChannel(SD‐SC‐01and‐02).

Generally, deposits coarsen with depth. The extent of cobbles and coarse gravel in the materialthroughoutthecoveisunclearbecausebothvibracoreandsplit‐spoonsubsurfacesamplingequipmentencounteredrefusalatseverallocations,whichwasmostlikelyoncobbles,althoughsamplescouldnotbecollected.Thus,thegeotechnicalsampleresultsmaynotreflectsomeofthecoarsermaterial(coarsegravelandcobbles)insomeareas.

Althoughrefusalwasmetatseverallocations,bedrockwasnotconfirmedinanyoftheexplorationsintheSouthernCove,norisitexpectedtobepresentintheremovalareas.Bedrockmapsdevelopedforthe upland portion of the site during the SI (CDM2003) indicate a phyllite bedrockwith elevationvaryingsteeply.ThebedrocksurfaceappearstooutcropwheretheSoutherlyStreamdischargestotheSouthern Cove, but maps indicate it may be 90 feet below ground surface along the beach at thenorthernendoftheSouthernCove.

Disposal Characterization Sedimentfromwithinthehorizontalandverticalextentsofthesedimentremovalareaswassampledfordisposal characterization.Methods and results aredetailed in thePre‐designActivitiesReport inAppendixA,andanoverviewofthestudiesisprovidedbelow.

MercuryintheSouthernCoveisassumedtobeprimarilyfromhistoricalwastewaterdischargesfromthe plant. Based on chemical data, the sediment is not a characteristic waste as defined by theU.S.EnvironmentalProtectionAgency(EPA)ResourceConservationandRecoveryAct(RCRA)ToxicityCharacteristicLeachingProcedure(TCLP)methods.Disposalcharacterizationconsistedofanalysesfora suite of chemical and physical characteristics typically required bywaste disposal facilities. Fourcomposite samples (SD‐SC‐07 through ‐10)were collected fromwithin theextentof each sedimentremovalareatocharacterizematerialforhandlinganddisposalrequirements.SamplinglocationsareshowninFigure1‐2.SampleswereanalyzedusingEPATCLPmethodsforvolatileorganiccompounds,semivolatile organic compounds,metals, pesticides, and select herbicides (i.e., 2,4,5‐TP and 2,4‐D).Sampleswerealsoanalyzedforasuiteofadditionalchemicalandphysicalcharacteristicsthatcouldberequired by disposal facilities. The results were either non‐detect or below the disposal facility


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requirements; thus, the material is not characteristically hazardous in accordance with RCRArequirementsandcanbecharacterizedassolid,non‐hazardous,waste.

Treatability Testing Sediment samples collected fordisposal characterizationwere also subject to treatability testing todeterminefeasiblepost‐removaldewateringmethodsfortheproject.DetailsofthestudyareincludedinAttachmentA.5tothePre‐designActivitiesReportinAppendixA.

The treatability testing evaluated the rate that sediments would dewater, the need for addingamendmentstoachievelowmoisturerequirements(i.e.,theabilitytopassthe“paintfilter”test),andthechemicalcompositionofthedewateringelutriateincomparisontotheon‐siteGWTPrequirements.Ingeneral,thematerialdrainedwell,andtheadditionofseveraltypesofamendmentswassuccessfulinachievingthelowmoisturerequirementsfortransportanddisposal.Dewateringelutriategenerallymetrequirements tobeacceptedbytheon‐siteGWTP,althoughsomefilteringmaybenecessarytoreducetheleveloftotalsuspendedsolids(TSS)priortodeliverytotheon‐siteGWTP.

Sediment Chemical Characterization Inadditiontosedimentsamplescollectedfortreatabilitytestinganddisposalcharacterization,sampleswerecollectedduringPDactivitiestocompletedelineationofmercury insediments,andtosupportdelineationofremovalareasthatwillmeetMPSrequirementsoutlinedintheOrder.Afulldescriptionof samples collected, objectives and results in presented in the Pre‐design Activities Report(AppendixA) and Proposed Delineation of Sediment Removal Areas for Basis of Remedial Design(DelineationTechnicalMemorandum;AppendixC).ResultsarealsodiscussedinSection4.

Intertidal Vegetation Survey Theextentofwetlandcommunitieswithintheprojectareaweredelineatedduringa fieldsurvey inMay2015.Atthetimeofthesurvey,theplantswithinthewetlandhadnotreachedfullgrowthfortheseasonbuthadgrownenoughfortheextentandspeciespresenttobeidentified.

Threeseparatewetlandcommunitieswereidentifiedcovering2.1acres,asshowninFigure2‐2.Thethreecommunitieswerecomposedofthefollowing:

Ahighmarshcommunityofbeakedspikerushgrowingneartheshorelineonathickbaseofpeat(0.15acre)

Multiple,sparsebedsofcommonthree‐squaregrowinginsoft,unconsolidatedmud(1.9acres)

Asmallbedofdenselygrowinghardstembulrushembeddedwithinthesparsecommonthree‐square,whichappearedtobegrowingpartlyonasmallchunkofpeatmataswellassoftmud(0.03acre)

OnlyoneofthespeciesidentifiedislistedasaMainerare,threatened,orendangeredplant.BeakedspikerushisidentifiedasthreatenedinMaine,asofSeptember2015,andwasidentifiedinthehighmarshcommunityattheOrringtonRemediationSite(MENaturalAreasProgram2015).

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Section 3. Design Objectives

Corrective Measures Implementation Plan Objectives TheprimaryobjectivesoftheremedyfortheSouthernCovearetoremovesedimentsthatareabovetheMPSasrequiredintheOrder,andtorestoremudlineelevationsandvegetationtopre‐remediationconditions.

Media Protection Standards TheMPSs identified in the Order require that sediment be removedwheremercury levels exceed2.2milligramsperkilogram,averagedovera0.25‐acrearea.Irrespectiveofconcentrations,sedimentwithinthetwohotspotareasidentifiedforthreeseparatedepthintervalsmustalsoberemoved.ThehotspotsaredefinedintheOrderbyboththemapandalistofsamplelocationsincludedasa“narrativeMPS”thatmustbeencompassedinthesedimentremovalareas.

Compliance with the Order Media Protection Standards TheOrder‐definedsedimentremovalareasandtheproposedsedimentremovalareasaredepictedinFigure2‐1andDrawingC‐4. The proposed sediment removal areas include the areas and depthsrequiredbytheOrder.ThebasisoftheproposedsedimentremovalareasandcompliancewiththeMPSisfurtherdescribedinthefollowingsubsections.

MallinckrodtsubmittedadraftDelineationTechnicalMemorandum(AppendixC)onOctober29,2015.Followingthatsubmittal,MallinckrodtpresentedanoverviewofthetechnicalmemorandumtoMaineDEPonFebruary18,2016,andreceivedcommentsfromMaineDEPbye‐mailonFebruary26,2016.MallinckrodtpresentedresponsestoMaineDEPcommentsduringawebinaronMarch15,2016.Basedon feedback received fromMaineDEP in itswritten comments, and comments received during theMarch15webinar,MallinckrodtsubmittedresponsestoMaineDEPcommentsandafinalDelineationTechnicalMemorandumtoMaineDEPonMarch25,2016,whichisincludedasAppendixC.Thereaderis directed to figures in the Delineation TechnicalMemorandum (AppendixC) that showmercuryconcentrations at various depths within the Southern Cove and are referenced in the followingparagraphs.

Inane‐mailtoMallinckrodtdatedApril4,2016,MaineDEPconcurredwiththeareastoberemovedwiththefollowingprovisions:

1. Theresultsfromtheadditionalsamplesshownbelowwillbereviewedtodetermineiftheyincreasethescopeoftheremovalarea.

Section 3 Design Objectives

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NorthernSedimentRemovalArea(SMA‐2) SouthernSedimentRemovalArea(SMA‐3)ProposedAdditionalRemovalAreaDelineationSamples

2. TheremovaldepthofthenorthernportionofNorthernSedimentRemovalArea(SMA‐2)willneedtobedeterminedinthefieldduringremovaloperations(seeSection7.3.1oftheDelineationTechnicalMemorandum[AppendixC]).

MallinckrodtconductedthisadditionalsamplinginMay2016,andsubsequentlyidentifiedtheneedforadditionalsamplecollectiontocompletedelineation.Tokeeptheprojectconstructiononschedule,thisdraftCMIPlanissubmittedbasedonpreliminarysedimentremovalareas,withtheunderstandingthatthefinalsedimentremovalareaswillbeadjustedbasedonnewsampledatatobegeneratedinJune2016.

Basedonrecentsamplingandreviewofhistoricaldata,threeproposedsedimentremovalareas/prismshavebeenidentifiedtomeettherequirementsintheOrder.ThehorizontalandverticalextentsoftheproposedremovalprismsareshownonAppendixCFigure9,alongwiththeremovalareasanddepthintervalsrequiredbytheMPSintheOrder.OnesectionoftheremovalareaidentifiedintheOrderwasexcludedfromtheproposedsedimentremovalareasbasedondatacollectedsincetheOrderwasissued,as described in Section 5.3.2. The Order included a vegetated wetland hummock east of SMA‐3(SouthernSedimentRemovalArea)wherenosampledatawereavailablefromtheSIandCMS.Samplescollected aspart of thepre‐design investigation fromSD‐SC‐22 (0 to0.2 and0.8 to1 foot) showedmercurylevelsbelow2.2milligramsperkilogram(mg/kg)atthislocation(seeimagebelow);therefore,itwasexcludedfromtheproposedsedimentremovalareas.


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SMA‐3 (Southern Sediment Removal Area) (0.8 to 1 foot) – Mercury MPS Compliance at SD‐SC‐22

The rationale for delineation of the horizontal and vertical extents of the three proposed sedimentremovalareasisexplainedinthefollowingsections.

Southern Sediment Removal Area (SMA‐3) ThehorizontalextentoftheproposedSouthernSedimentRemovalArea(SMA‐3)includesallsamplelocationsintheareaexceeding2.2mg/kginanysampleddepthintervals,asdepictedonAppendixCFigure7.Oneexceptionoutsidetheremovalareaisaconcentrationof2.6mg/kgmercurydetectedatSD‐10‐C1from0to0.2foot(seeimagebelow).However,withconsiderationofsamplesfromthesamedepthintervalwithina0.25‐acreareathatincludesSD‐10‐C1,theaveragemercuryconcentrationofthe0.25‐acrearea is2.1mg/kg,which is less than theMPS (seeAppendixCFigure2).Therefore, thissamplelocationisnotincludedintheproposedSouthernSedimentRemovalArea(SMA‐3).


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SouthernSedimentRemovalArea(SMA‐3)(0to0.2foot)–MercuryMPSCompliancewithin0.25acreatSD‐10‐C1

Forverticaldelineation inSouthernSedimentRemovalArea(SMA‐3),datadepictedonAppendixCFigures2and3showmercuryconcentrationsexceedingtheMPSinthetop1footofsediment.Alldatafromsedimentsamplescollectedbelow1‐footdepthshowmercuryconcentrationsbelow2.2mg/kg(Appendix C Figures 4, 5, and 6) with the exception of sample SD‐10‐B4, which had 5.7mg/kgmercuryat1.5‐ to2‐footdepth(AppendixCFigure5).However,adjacentsampleshad less than1mg/kgmercuryatthesamedepthintervalforanaverageconcentrationof1.6mg/kgovera0.25‐acreareawithinthe1.5‐to2‐footdepthinterval.Basedontheseresults,theproposeddepthforSouthernSedimentRemovalArea(SMA‐3)dredgeprismis1foot.

Based on comments received from Maine DEP on the draft Delineation Technical Memorandum(AppendixC),Mallinckrodtcollectedthe followingsamples inMay2016,andwillcollectadditionalsamplesinJune2016tocompletedelineation:

NorthandEastofRSD‐15AandRSD‐15B:Threeadditionalsampleswillbecollectedtocompletedelineation—onenorthofSouthernSedimentRemovalArea(SMA‐3)andtwototheeast,asshownintheimagebelow.Sampleswillbecollectedfrom0‐to0.2‐footand0.8‐to1‐footdepthintervals.


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Delineation at RSD‐15A and RSD‐15B – Southern Sediment Removal Area (SMA‐3)

Southerly Stream Sediment Removal Area (SMA‐1) The horizontal extent of the proposed Southerly Stream Sediment Removal Area (SMA‐1) wasestablishedbasedonmercuryconcentrationsgreaterthan2.2mg/kgandapplyingthenarrativeMPSofanaveragemercuryconcentrationoflessthan2.2mg/kgovera0.25‐acreareatosamplelocationsoutside the proposed removal area, as shown on Appendix C Figures 2 and 3. The averageconcentrationwascalculatedbasedonsamplesfromsimilardepthintervals.Theproposeddepthofthisremovalareais0.8foot(AppendixCFigure9)basedonconcentrationsmeetingtheMPSinsamplesfromthe0.8‐to1‐footdepthinterval.

SoutherlyStreamSedimentRemovalArea(SMA‐1)(0.8to1foot)–MercuryMPSCompliance


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Northern Sediment Removal Area (SMA‐2) ThehorizontalextentofNorthernSedimentRemovalArea(SMA‐2)iswelldefinedbysampledataandencompassesalldatapointsthatexceed2.2mg/kginthisvicinity.Thisremovalareahasbeendividedintothreesubsectionsbasedondifferencesinthedepthofmercurycontamination,asdiscussedinthefollowingsectionsandshownonAppendixCFigure9.

Northern Sediment Removal Area (SMA‐2) – Northern Portion

The highest and deepest mercury concentrations are found in the northern portion of NorthernSedimentRemovalArea (SMA‐2),which is close toaMainePollutantDischargeEliminationSystem(MEPDES)discharge.Theelevatedconcentrationsofmercuryarelocalizedanddecreaserapidlyinthehorizontaldirectionout fromRSC‐024, the locationwiththehighestconcentration,especially to thewestwithincreasingwaterdepthtowardthemainriverchannel.Theproposedremovaldepthis3feetintheareaofhighestmercuryconcentrations,correspondingtothedeepestmeasuredinterval,withmercurygreaterthan2.2mg/kg(sampleSD‐SC‐07from30to36inches).However,becausethepre‐design investigation sampling equipment could not penetrate to deeper depths, it is unclear if thecontaminationextendsdeeperthan3feetinthisarea.AdditionalsamplingwillbecompletedinJune2016toestablishthedredgedepthinthisarea.

Based on comments received from Maine DEP on the draft Delineation Technical Memorandum(AppendixC),MallinckrodtcollectedthefollowingsamplesinMay2016,andallresultswerelessthan2.2mg/kgmercury (thedatawillbepresentedalongwith theadditional June2016sampledata tofinalizethesedimentremovalareas):

NorthandEastofRSC‐11G:SedimentsamplesfromtwoadditionallocationseastofSMA‐2(NorthernSedimentRemovalArea)asshownintheimagebelow.Fromeachlocation,sampleswillbecollectedfromtwodepthintervalsbetweensurfaceand2feet.


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RSD‐11G – Northern Sediment Removal Area (SMA‐2)

Northern Sediment Removal Area (SMA‐2) – Southern Portion

MercuryconcentrationsinthesouthernportionofSMA‐2(NorthernSedimentRemovalArea)arelowerthantothenorth,butstillexceedtheMPSinthetop2feet.Thedeepersample(SD‐SC‐08)indicatesamuchlowermercuryconcentrationof0.06mg/kgat3feetdepth. Therefore, theproposedremovaldepthinthisareais3feetbasedonsampleresults.

Northern Sediment Removal Area (SMA‐2) – Western Edge

Mercury concentrations show a rapid decrease in concentration and contaminant depth along thewesternedgeofNorthernSedimentRemovalArea(SMA‐2)andtowardthemainriverchannelwherewaterdepths increase.Thus, theremovaldepthofthewesternedgeofNorthernSedimentRemovalArea(SMA‐2)isproposedat1foottomeettheMPS.

Definition of Preliminary Sediment Removal Areas Basedonpre‐designsamplingandreviewofhistoricaldatadescribedherein,threesedimentremovalareashavebeenidentifiedandaredescribedintheDelineationTechnicalMemorandum(AppendixC).TheseareasareshownonFigure2‐1andDrawingC‐4,alongwiththeremovalareasanddepthintervalsrequiredbytheMPSdefinedintheOrder.Asdescribedabove,additionalsampleswerecollectedinMay2016atMaineDEP’srequest.Basedonthosesampleresultsandtheinabilityofequipmenttopenetrate


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torequireddepths,MallinckrodtwillcollectadditionalsamplestocompletedelineationinJune2016.FinalsedimentremovalareaswillbepresentedinthenextversionoftheCMIPlan.

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Section 4. Southern Cove Corrective Measures Implementation Activities

Overview of the Remedial Action The Southern Cove remedial action will involve removal of sediment to comply with the MPS, asdescribed in previous sections, and restoration of the removal areas to pre‐construction elevation.DetailsofthecorrectiveactionimplementationareprovidedinthedesigndrawingsinAppendixE,theTechnicalSpecificationsinAppendixF,andthefollowingsections,whichareorganizedasfollows:

Section4.2–ExistingConditionsandSitePreparation

Section4.3–SedimentRemovalandProcessingActivities

Section4.4–EnvironmentalControls

Section4.5–RestorationActivities

TheConstructionQualityAssurancePlanispresentedinAppendixG.

Existing Conditions and Site Preparation Prior to beginning sediment removal activities, support areas for staff and equipment, access tosediment removal areas, and sedimentmanagementand stockpilingwill be established.Temporaryerosion and sediment control measures will also be established. Each of these requirements aredescribedinthefollowingsubsections.

Site Trailers/Offices

Trailers forMallinckrodt, theRemediationProjectManager(RPM), theConstructionQualityControl(CQA)Engineer,andMaineDEP;anon‐sitelaboratory;andrestroomfacilitieswereestablishedduringprevious site work phases. The Remediation Contractor will be responsible for providing its owntrailerstobeinstalledintheRemediationContractorOfficeTrailerComplexshowninDrawingG‐7.

Site Staging

Asmallstagingarea(labeledasNearshoreSupportAreainDrawingG‐4)willbeestablishedaspartofthe Northern Drainage Ditch CMI Plan (submitted to the Maine DEP on February 5, 2016). TheRemediationContractorwillusethisareatooffloaddredged/excavatedsedimentsfortransporttotheSediment Management Area (SMA), and to load clean materials for backfilling. The RemediationContractorwillberesponsibleformaintainingtheconditionofthestagingareapadinaccordancewithDrawingC‐9andtheTechnicalSpecifications(AppendixF,Section015000).

Sediment Processing and Stockpiling Areas

SedimentwillbestockpiledanddewateredattheRemediationSupportArea,whichhasbeenpreviouslyestablishedandisoperatedfortheentireOrringtonRemediationSite(bothsoilandsediment)bytheRPM (see location inDrawingG‐4).Dredgedandexcavated sedimentwill be transported from theNearshore Support Area to the Remediation Support Area in sealed containers or trucks. Prior totransferringthesedimentonshore,theRemediationContractorwillremoveanyaccumulatedoverlyingwater(seeSection4.3.2).Sedimentwillbedewateredbymixingadditives(e.g.,cementorotherdrysitesoils) directly into the sediment on a processing pad as shown in Drawing G‐3. Any necessaryenhancements to theprocessingpadwillbedeterminedafter theRemediationContractorhasbeen

Section 4 Southern Cove Corrective Measures Implementation Activities

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selected;however,ataminimum,thepadwillmeettherequirementsshowninDrawingC‐3.Stockpilesof dewatered sediment will be managed in accordance with Drawing C‐3 and the TechnicalSpecifications(AppendixF,Section015719).

Clean stockpile areas for import backfill have been previously established andwill bemanaged tominimizedust.

Access Roads

TheaccessroadbetweentheNearshoreSupportAreaandtheexistingRemediationSupportArea(seeDrawingG‐4)willbeestablishedaspartoftheNorthernDrainageDitchCMIPlan.Materialtransferredalongthisaccessroadwillbecontainedwithinsealedcontainersortrucks;therefore,housekeepingoftheroadisexpectedtobeminimal.Thisroadwillremaininplaceafterconstructioniscomplete.

ToaccessSoutherlyStreamSedimentRemovalArea(SMA‐1),theRemediationContractorwillneedtoestablish access along the shoreline. The exact method of access will be determined after theRemediationContractorhasbeenretained;however,itisexpectedthattheRemediationContractorwilluseexistingtideflatssupplementedbymarshorcranemats,wherenecessary,thatareresilienttothehightideandminimizedisturbanceof thearea. Ifcontaminatedmaterialsaretransferredalongthisaccessroad,theywillbecontainedwithinsealedandcoveredcontainers;therefore,housekeepingoftheroadisexpectedtobeminimal.TheRemediationContractormayelecttobuildadditionalaccessroadsusingsimilarmethodsthroughtheSouthernCovetoaccessthesedimentremovalareas.Alloftheseroadswillberemoved,andthearearestored,afterconstructioniscomplete.

Temporary Erosion and Sediment Control

It isnotexpectedthatactivities immediatelyadjacenttotheSouthernCovewillsignificantlydisturbuplandsoilsandrequiretemporaryerosionandsedimentcontrols(TESCs)perMaineDEPStormwaterConstructionGeneralPermitconditions.However,asshowninDrawingC‐1,siltfenceswillbeinstalledbetweentheNearshoreStagingAreaandtheriverasaprecautiontocontainanyaccidentalspillsduringsediment transfer. Existing TESCs around the Remediation Support Area will be maintained andsupplemented, as necessary, in accordance with the Technical Specifications (Appendix F,Section015719).

Sediment Removal and Processing Activities Thissectiondescribes theremovalof sediment fromthe threesedimentmanagementareas (SMAs)shown inDrawingC‐4, the controls that will be used tominimizewater quality impacts, and theanticipatedprocessesnecessarytopreparetheremovedsedimentforoff‐sitetransportanddisposal.ThenatureandextentofsedimentcontaminationandtherationalefortheremovaldepthsforeachSMAarediscussedinSections2.8and3.3.

Excavation

The existing bathymetry surrounding Southerly Stream Sediment Removal Area (SMA‐1) is veryshallowandwaterlevelsathightidelimittraditionalfloatingdredgingequipmentaccess.Therefore,itis expected that the Remediation Contractor will remove the sediment within Southerly StreamSedimentRemovalArea(SMA‐1)usingtraditionalland‐basedexcavationequipmentduringlowtide.Theapproximatevolumeofsedimenttargetedforremovalfromthisareais230cubicyards(cy),andexcavationswilllikelyoccuroverseveraltidalcycles.

TheareaofworkthatcanbecompletedwithinatidalcyclewillbedesignatedasaCertificationUnit(CU).Tominimizethepotentialforrecontaminationbetweentidalcycles,eachCUwillbeimmediatelybackfilledafterverificationthatthedesignremovaltargets, intermsofdepthandextent,havebeenachievedandverifiedbytheCQAEngineer.CUverificationwillbebasedontraditionalsurveymethods


4‐3

toverifythattherequiredremovaldepthhasbeenachievedthroughouttheexcavation.TheTechnicalSpecifications (Appendix F, Sections022100 and 352023) include minimum requirements forsurveyaccuracyandperformance.

Dredging

SedimentremovalwithinNorthernSedimentRemovalArea(SMA‐2)andSouthernSedimentRemovalArea(SMA‐3)willoccurpredominatelyusingtraditionalmechanicaldredgingequipment.TherequiredremovalareasanddepthsareshowninDrawingC‐4andthesequenceofworkwillgenerallyoccurfromupstreamtodownstream.Theapproximatevolumeofsedimenttargetedforremovalfromtheseareasis4,390and2,000cy,respectively.TheTechnicalSpecifications(AppendixF,Sections022100and352023)includedetailedrequirementsforpositioningcontroltoensurethattheRemediationContractor removes the sediment with the most practicably achievable precision. The TechnicalSpecificationsalsoincludebestmanagementpracticesthatmustbefollowedtominimizethepotentialtogenerateexcessiveturbidityduringdredgingandrecontaminationofpreviouslydredgedareas.

DredgingwilloccurwithinamobileturbiditycurtainsystemasshowninDrawingC‐2.EachpositionofthesystemwilldefineadredgingCU.PriortomovingthesystemtothenextCU,theRemediationContractorwillsurveythedredgedareainaccordancewiththeTechnicalSpecifications(AppendixF,Section352023)andtheCQAEngineerwillverifythattherequiredremovaldepthhasbeenachieved.Onceapproved,theRemediationContractorwillplaceaninitialbackfilllayerandthenmoveontothenextCU.The intent of the initial backfill layer is to stabilize any thin veneerof disturbed sedimentremainingonthepost‐dredgesurfacetominimizethepotentialforsubsequentwaterqualityimpacts.

TheRemediation Contractorwill place the dredged sediment either into a storage barge (scow) ortransport containers located on a flat‐deck barge. Overlyingwater that accumulates in the scoworcontainers will be filtered in accordance with the Technical Specifications (AppendixF,Section015719) before discharge to the river. The overlying water must be removed prior toinitiating transfer of the sediment onto land tominimize the potential for sloshing or spills duringtransferandtransport.SedimentwillfirstbetransferredonlandattheNearshoreSupportAreaandthentransportedviatheaccessroadtoTSSA‐2forprocessing.

TheeasternportionofNorthernSedimentRemovalArea(SMA‐2)containstwoindustrialoutfallsthatrequirespecialconsiderationduringdredgingandexcavation.Theareasimmediatelyadjacenttotheindustrial outfalls will be dredged using careful procedures, and potentially special dredgingequipment,topreventdamagetotheoutfall.Theseareaswillbedredgedinsmall‐areaintervalsandimmediatelybackfilledwithcleanbackfilltopreventunderminingoftheoutfalls.

ThenorthernportionofNorthernSedimentRemovalArea(SMA‐2)containsanareaofhardsubgradeinthevicinityofstandardpenetrationtest(SPT)boringlocationSD‐SC‐07.DuringtheSPT,extremelyhardmaterialwasencounteredat3.3feetbelowgroundsurface(bgs)andanN‐valueof177wasreported.TheRemediationContractorwillattempttodredgetheCUsurroundingSD‐SC‐07toadepthof3.5feetbgs(i.e.,toadepthdeeperthantherefusalintervalencounteredduringtheSPT)asshowninDrawingC‐4.Ifrefusaloccurspriortoreaching3.5feetbgs,dredginginthisCUwillbeconsideredcomplete.DepthverificationandinitialbackfilllayerplacementwillproceedconsistentwithotherCUs.

Dredged Material Processing

Priortofinaloff‐sitetransporttothedisposalfacility,thedredgedmaterialwillrequiredewateringandverificationusingthepaintfiltertest.BasedontheresultsoftheTreatabilityStudy(AttachmentA.5ofthePre‐designActivitiesReportinAppendixA),blendingthesedimentswithotherexcavatedon‐sitesoils(inaccordancewiththeSoilUsePlanapprovedbyMaineDEP)isexpectedtobesufficienttoreducethemoisturecontentofthedredgedsedimentstolevelsacceptablefortransportanddisposal.Inthe


4‐4

event that on‐site material is not available at the time of dewatering, another economical, well‐performingagentfromtheTreatabilityStudywillbeused.

Environmental Controls Monitoring of the environment will occur throughout the construction period. The RemediationContractorwillprepareanenvironmentalpollutionprotectionplanthatwillincludegeneralcontrolsregardingspillprevention,dustandodors,noise,light,TESCs,fuelstorage,equipmentdecontamination,wastemanagement,andotherenvironmentalconsiderations.TheRPMwillberesponsibleforairandwater quality monitoring and fish observations in accordance with permit requirements. ThismonitoringisdescribedinthePerimeterAirMonitoringPlan(CDMSmith2015)andtheWaterQualityandFishMonitoringPlan(AppendixD).

Asdiscussedintheprevioussection,dredgingwilloccurwithinamobileturbiditycurtainsystemasshown inDrawingC‐2.AppendixBdescribes the site conditions and engineering evaluations thatwereusedtoselectamobilesysteminlieuoftheuseofastationaryturbiditybarrierenclosingtheentireSouthernCoveworkareas.TheRemediationContractorwillberesponsibleforthefinaldesign,operation,andmaintenanceofthesystem.

Duringtransferofsedimentonshore,theRemediationContractorwillestablishtemporarycontrolsasshowninDrawingC‐9tocontainanypotentialspillsthatmayoccurduringtransferandtransporttoTSSA‐2.

Water Quality and Fish Monitoring

WaterqualityandfishmonitoringrequirementswillbefinalizedbasedonthepermitsissuedbytheU.S.ArmyCorpsofEngineers.Mallinckrodt’sproposedapproachisdescribedintheWaterQualityandFishMonitoringPlan(AppendixD).

Waterqualitywillbemonitoredduringallin‐waterworkeitherbyhandfromasmallutilityboat,orusingtwoanchoredbuoys.MonitoringpointswillbelocatedinthePenobscotRivernorthandsouthofthe Southern Cove. The upstream and downstream location will be determined based on tidalconditionsandflowdirection.Thewaterqualitymonitoringcriteriathatwilltriggercorrectiveactionsare35nephelometricturbidityunits(NTUs)higheratthedownstreambuoycomparedtotheupstreammeasurement.

Priortocommencingsedimentremovalwithamobileturbiditycurtainsystem,thecontaineddredgeareawillbecheckedforthepresenceofAtlanticsalmonorAtlanticorshortnosedsturgeon,whicharelistedspeciesundertheEndangeredSpeciesAct.Ifthesespeciesareidentified,thefishwillbeclearedfromtheareapriortocommencingdredging.

Water Treatment

Watergeneratedduringsedimentdewateringwillbesentthroughtheon‐siteGWTPanddischargedunderthecurrentMEPDESpermit(#ME0000639).Storagetanksonsitemaybeusedfortemporarystorageasneeded.Waterwillbe tested toverify that itmeets influent requirements for theon‐siteGWTP.

TheSouthernCoveCMIhasbeendesignedtominimizethevolumeofwaterdirectedthroughtheon‐siteGWTP.OverlyingwaterfromsedimentwillbedecantedonthebargeanddischargedtotheriveratthepointofdredgingpriortotransporttoTSSA‐2.Itisanticipatedthatpre‐filteringofthedecantedwaterprior to discharge into the rivermay be required tomeetwater quality standards required in theproject’sCleanWaterAct(CWA)Section401WaterQualityCertification.

The sediment dewateringmethodwill include a stabilization process that generates limited excesswater.Anydewateringeffluentgeneratedduringdewateringactivitieswillbetransferredtotheon‐site


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GWTPforprocessingpriortodischargeinaccordancewithMEPDESpermitlimits.Asacontingency,existingstoragetanksmaybeusedtotemporarilystoredewateringeffluentsothatGWTPcapacityisnotexceeded.Dewateringeffluentwillbetestedtodetermineifitmeetsinfluentcriteriaoftheon‐siteGWTP.BasedonresultsoftheTreatabilityStudy,itispossiblethatthewaterwillexceedTSScriteriaandrequirepre‐treatmentpriortobeingdeliveredtotheGWTP.

Restoration Activities

Backfilling

Eachareaexcavatedordredgedwillbebackfilledtopre‐constructiongrades.Thebackfillmaterialwillconsistofimportedcleangravelysand,similarinsizedistributiontomaterialscurrentlyfoundwithintheSouthernCove.

As stated inSection4.3.1,backfillingofSoutherlyStreamSedimentRemovalArea (SMA‐1)CUswilloccurduringthesametidalcycleinwhichdredgingoccurs.InNorthernSedimentRemovalArea(SMA‐2)andSouthernSedimentRemovalArea(SMA‐3),eachverifiedCUwillbebackfilledwithan initialbackfillliftpriortorepositioningthemobileturbiditycurtainsystemtoanadjacentCU,asdiscussedinSection4.3.2.AfterallCUsaredredged,theremainingbackfillmaterialwillbeplacedtoreturntheareasto pre‐construction grades. The placement of the final layer of backfill will generally occur fromupstreamtodownstreamlocations.Post‐constructionsurveyswillbeusedtoconfirmthattheareashavebeenreturnedtopre‐constructiongradeswithinacceptabletolerances.

The preliminary limits of areas requiring revegetation are shown inDrawingC‐10. In addition togravely sandbackfill, these areaswill receive a 6‐inch layer of habitat‐amendedbackfill to supportsubsequentplantingandseeding.

Planting and Seeding

TheplantingandseedingplanshowninDrawingC‐10willbefinalizedbasedonobservationsmadeduringdredgingactivities.TheRPMwillverifytheextentsandtypesofwetlandvegetationimpactedbyconstructionoperations.

Depending on the completion date of backfilling activities, planting and seeding activities may bedelayeduntil thefollowingspringonce ice isthawedandtemperaturessupportplantestablishmentandseedgermination.

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Section 5. Permitting

ThefollowingpermitsareneededfortheSouthernCoveCMIactivities:

ShorelandProtectionActPermit.ApermitapplicationwassubmittedonApril5,2016,totheOrringtonCodeEnforcementOfficerforworkwithin250feetfromthePenobscotRiverfortheentireOrringtonRemediationSite.WithrespecttotheSouthernCoveCMI,thispermitcoversconstructionandmaintenanceofstagingareasandaccessroadsnecessarytoperformsedimentremoval.

MaineIndividualPermit.TheMaineIndividualPermitincludestheCWASection401WaterQualityCertification,CWASection404,andSection10oftheRiversandHarborsActof1899.The following required consultation is also completed by theU.S. ArmyCorps of Engineersbeforegrantingthepermit:

Section106oftheNationalHistoricPreservationActandwithlocalTribes

Section7consultationswithNationalOceanicandAtmosphericAdministration,NationalMarineFisheriesService,andU.S.FishandWildlifeServiceforEndangeredSpeciesActandEssentialFishHabitat

MaineNaturalResourcesProtectionAct.Permit‐by‐rulewasgrantedbytheMaineDEPfortheentireOrringtonRemediationSite,includingtheSouthernCove.

FollowinginitialreviewoftheCMIPlanbyMaineDEP,MallinckrodtwillsubmittheMaineIndividualPermitapplication,whichshouldoccurinfall2016.ThissubmissionwillincludethedraftCMIPlan(revisedtoaddressMaineDEP’sinitialcomments)andthedraftRemediationContractorWorkPlans.

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Section 6. Schedule

TheanticipatedschedulefortheSouthernCoveispresentedinTable6‐1.ThisscheduleiscontingentonMaineDEPapproval.

Table 6‐1: Proposed Southern Cove Schedule

Activity Anticipated Start Date

Anticipated End Date

Submit Southern Cove CMI Plan to Maine DEP -- June 8, 2016 Maine DEP Preliminary Review of CMI Plan June 8, 2016 August 12, 2016

Meet with Maine DEP -- June 15, 2016 Revise CMI Plan with Remediation Contractor

Work Plans and Submittals July 11, 2016 November 16, 2016

Meet with Maine DEP -- January/February 2017 Finalize CMI Plan January 23, 2017 March 14, 2017

Final Maine DEP Approval -- April 25, 2017 Remediation Contractor Mobilization -- Mid-June 2017

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Section 7. References

AnchorQEA,LLC,2014.HealthandSafetyPlan.SouthernCove,OrringtonRemediationSite.PreparedforCDMSmith,Inc.December2014.

Anchor QEA, LLC, and CDM Smith, Inc., 2015. Southern Cove Pre‐design Work Plan. OrringtonRemediationSite,Orrington,Maine.PreparedforMallinckrodtUSLLC.June2015.

CDM(CampDresser&McKeeInc.),1998.SiteInvestigationReportVolumeI.HoltraChemManufacturingSite,Orrington,Maine.December22,1998;RevisedAugust15,2001.

CDM,2003.CorrectiveMeasuresStudy.Mallinckrodt Inc.,HoltraChemManufacturingSite,Orrington,Maine.May27,2003;RevisedSeptember19,2003.

CDM Smith, 2014a. Quality Assurance Project Plan. Orrington Remediation Site, Orrington, Maine.RevisionNo.01.December15,2014.

CDM Smith, 2014b. Project Health and Safety Plan. Orrington Remediation Site, Orrington, Maine.October9,2014.

CDMSmith,2015.PerimeterAirMonitoringPlan(PAMP),OrringtonRemediationSite,Orrington,Maine.June25,2015.

MaineBEP(MaineBoardofEnvironmentalProtection),2010.AppealofDesignationofUncontrolledHazardousSubstanceSiteandOrder,FindingsofFactandOrderonAppealintheMatterofUnitedStatesSurgicalCorporationandMallinckrodtLLCConcerningaChlor‐alkaliManufacturingFacilityin Orrington, Penobscot County, Maine Proceeding Under 38 M.R.S.A. § 1365, UncontrolledHazardousSubstanceSitesLaw;August19,effectivedateApril3,2014.

MaineDEP(MaineDepartmentofEnvironmentalProtection),2008.ComplianceOrder:DesignationofUncontrolled Hazardous Substance Site and Order in the Matter of United States SurgicalCorporation, Mallinckrodt LLC Concerning a Chloralkali Manufacturing Facility in Orrington,PenobscotCounty,MaineFormerlyOwnedandOperatedbyMallinckrodtInc.,ProceedingUnder38M.R.S.A.§1365,UncontrolledHazardousSubstanceSitesLaw;November24.

MaineNaturalAreasProgram,2015.DepartmentofAgriculture,ConservationandForestry.ElementsofDiversityRare,ThreatenedandEndangeredPlants.September2015.

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RSD-11D

RSD-11E

RSD-11F

RSD-11G

RSD-11H

RSD-12ARSD-12B

RSD-12C RSD-12DRSD-12E

RSD-13A

RSD-13BRSD-13C RSD-13D

RSD-13E

RSD-14A

RSD-14BRSD-14CRSD-14D

RSD-15A

RSD-15B

RSD-15CRSD-15D

RSD-15E

RSD-15FRSD-15G

RSD-15H

RSD-16A

RSD-16B

SD10-A1

SD10-A2

SD10-A3

SD10-A4

SD10-A5

SD10-B1SD10-B2

SD10-B3SD10-B4SD10-B5

SD10-C1SD10-C2

SD10-C3SD10-C4SD10-C5

SD-SC-07

SD-SC-08

SD-SC-09

SD-SC-10

SD-SC-11SD-SC-12

SD-SC-13 SD-SC-14

SD-SC-15

SD-SC-16SD-SC-17

SD-SC-18

SD-SC-19

SD-SC-20

SD-SC-22

SD-SC-23

SD-SC-24SD-SC-25

SD-SC-1

SD-SC-2

SD-SC-3

SD-SC-4

SD-SC-5

SD-SC-6

SD-SC-23

SD-SC-24

SD-SC-20

SD-SC-25

SD-SC-22


Southerly Stream

Sample Locations!R 1995 Sample Location

"J 1997 Sample Location

#I

2001 Sample Location

$1 2015 Sample Location

T( 2015 Geotechnical Sample Location

Dredge Depth Delineation0.8 feet

1 foot

3 feet

3 feet(Final Dredge Depth To BeAdjusted During Construction)

Proposed Sediment Removal Area

Sediment Removal Arearequired by Order MPS

0 - 0.2 feet

0.8 - 1 feet

> 1 feet

MEPDES Outfall

PERC Outfall

Stream

Figure 2-1Sediment Removal Areas and Depths


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0 50 100 150 200Feet

[Note:Proposed sediment removal areas represent the minimum removal limits; the boundaries may be optimized for efficient construction.


Southerly Stream

Sample Locations!R 1995 Sam ple Location"J 1997 Sam ple Location

#I2001 Sam ple Location$1 2015 Sam ple Location

Proposed Sedim ent Rem oval Area

Mercury Concentrations (mg/kg)! ≤ 2.2! > 2.2

Wetland Community BoundaryHig h Marsh /Sedge BedDense Hardstem Bu lru shSparse Th ree-squ are Sedge

MEPDES Ou tfallPERC Ou tfallNorth ern Drainage DitchStream

Figure 2-2Extent of Intertidal Vegetation

Corrective Measu res Im plem entation PlanSou th ern Cove, Orring ton Rem ediation Site

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0 50 100 150 200Feet[

southern cove orrington remediation site orrington, … · sediment chemical characterization ......

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