# FIVE-YEA R REVIE W REPOR T RI02942 F 

## o r 

# i 

# ^ ' - 1 FIVE-YEA R REVIE W O'CONNO R COMPAN Y SIT E AUGUSTA , MAIN E RESPONS E ACTIO N CONTRAC T (RAC) , REGIO N I Fo r 

## U.S . Environmenta l Protectio n Agenc y



## B y Tetr a Tec h NUS , Inc . EP AContrac t No . 68-W6-004 5 EP AWor k

Assignmen t No . 123-FRFE-013 3 TtNU S Project No . N425 4 Septembe r200 2 TETR ATEC H NUS , INC .FIVE-YEA RREVIE W REPOR T

F . O'CONNO RSUPERFUN D SIT E AUGUSTA , MAIN E



### Prepare d by : U.S . Environmenta l Protectio n Agenc y

Regio n I Boston , Massachusett s 

# I . Richar dC^vagnero , Actin g Directo r Offic e o f Sit e Remediatio nan dRestoratio n Dat eUNITE D STATE S ENVIRONMENTA L PROTECTIO N AGENC Y REGIO N 1 1 CONGRES S STREET , SUIT E 110 0 BOSTON , MASSACHUSETT S 02114-202 3

MEMORANDU M 

### DATE : SUBJ : FROM : THRU : TO : 

### Septembe r

13 , 200 2 Five - Year Revie w FO'Conno r

Superfun dSit e Nanc y Terrenc e Connell y

i ' ' A> , , . , ' / / 

### Mar y Jan e O'Donnjjl , Chie f ' ME , VT , an dC T Superfun dSectio n Richar dCavagnero , Actin g Dir&fyorj'/ Y / OSR R**' ' ' l 

### Summar y o f

Actio n Attache dfo r

you r revie w an dsignatur e i s th e firs t five-yea r revie w repor t

fo r th e FO'Conno r Superfun dSite , th e ("Site" ) i nAugusta , Main e Thi s revie w cover s al l thre e operabl e unit s o f th e Sit e EP A Regio n1 conducte dthi s revie w pursuan t t o CERCL A sectio n12 1 (c) , Nationa l Oi l an d Hazardou s Substance s Pollutio nContingenc y Pla n(NCP ) sectio n300.430(f)(4)(ii) , an dOSWE R Directive s 935 5 7-0 2 (Ma y 23 , 1991) , an d9355.7-02 A (Jul y 26 , 1994) . Thi s i s astatutor y review , conducte dfo r

post-Octobe r

17 , 198 6 Remedia l Action s Th e purpos e o f afive-yea r revie w i s t o ensur e tha t

aremedia l actio nremain s protectiv e o f huma nhealt han dth e environmen t Majo r Issue s N o majo r issue s wer e identifie di n th e five-year revie w proces s A n analysi s o f th e technical practicabilit y o f

restorin g th e groundwate r beneat hth e sit e t o drinkin g wate r qualit y withi na reasonabl e timefram e wa s underwa y prio r t o th e star t

o f th e revie w EP A ha s determine dtha t i t i s technicall y impracticabl e fro ma nengineerin g perspectiv e t o attai nfedera l an dstat e drinkin g wate r standard s fo r

alimite dportio no f

th e Site , an di s thu s waivin g attainmen t o f thes e ARAR s fo r tha t portio no f

th e Sit e ( A RO D amendmen t documentin g thi s chang e i s bein g prepare dfo r signatur e withi nth e nex t

tw o weeks )

### Th e five-yea r revie w proces s reveale dtha t th e remedie s fo r

al l thre e operabl e unit s hav e bee n implemente di n accordanc e withth e requirement s o f th e 198 9 ROD , a s modifie db y th e 199 4 ES D an d199 5 contingenc y remedy . Th e remedia l actio n fo r

sourc e contro l (OU-1 ) ha s bee n complete dan di s protectiv e o f huma n healt han dth e environment . Exposur e pathway s tha t coul dresul t

i n unacceptabl e ris k

ar e bein g _ _ controlled . Th e fmalizatio no f th e O& M pla n wil l ensur e tha t th e OU- 1 remed y wil l remai n protective . Th e remed y fo r

managemen t

o f migratio n (OU-2 ) i s protectiv e o f huma n healt han dth e environment . Fo r

alimite dportio n o f

th e site , becaus e o f

th e presenc e o f

residua l oi l i n th e subsurfac e an dPC B an dVO C concentration s tha t ca n no t mee t RO D targe t

cleanu p levels , a technica l impracticabilit y waive r ha s bee n granted . Ongoin g oi l recover y an dinstitutiona l control s ensur e tha t

exposur e pathway s tha t

coul dresul t

i nunacceptabl e ris k

ar e bein g controlled . Th e remed y a t

OU- 3 i s expecte dt o b e protectiv e o f huma n healt han dth e environmen t upo n completio n o f

th e 10-year

samplin g program . I n th e interim , exposur e pathway s tha t coul dresul t i nunacceptabl e risk s ar e bein g controlled . Curren t dat aindicat e tha t

PC B concentration s i n th e sediment s o f

Rigg s Broo k

ar e slightl y abov e th e trigge r leve l i n isolate dan dsporadi c occurrence s Fis htissu e PC B concentration s hav e remaine dbelo w th e RO D targe t goal , Headquarter s Perspective/Involvemen t Headquarter s provide dcomment s o n th e draf t five-yea r revie w repor t

a s par t o f it s revie w o f

al l five-yea r review s followin g th e Jun e 200 1 guidanc e documen t "Comprehensiv e Five-Year Guidance" , OSWE RNo . 9355.7-03B-P . Thes e comment s hav e bee n addressed . Publi c Involvemen t EP A issue dapres s releas e o n Ma y 8 , 200 2 tha t wa s publishe di n th e Kennebe c Journa l announcin g EPA' s revie w o f th e progres s o f

th e O'Conno r

Sit e cleanup . Th e pres s releas e encourage dpubli c participation . Ther e i s n o establishe dCommunit y Advisor y Group . T o dat e EPA , Main e DE Pan dCentra l Main e Powe r (PRP ) hav e encountere dlittl e participatio n o r involvemen t

fro mth e loca l community . Al l site-relate ddocument s ar e availabl e a t th e Lithgo w Publi c Librar y i nAugusta . Accordin g t o staf f a t th e librar y ther e ha s bee n limite dus e o f th e document s A notic e whic hbriefl y summarize s thi s five-yea r revie w wil l b e publishe di namajo r loca l newspape r

o f genera l circulation . Media-Congressiona l Involvemen t Ther e ha s bee n n o medi ao r congressiona l involvemen t regardin g th e five-yea r

revie w process . Stat e Coordinatio n Main e DE Pha s participate di nth e revie w process , includin g th e sit e inspection , interviews , an d

### ha s provide dcomment s o n th e draft five-yea r revie w report . Main e DE Pexpresse dconcern s ove r th e fmalizatio no f

th e O& M plan , an drequeste dspecifi c languag e regardin g th e statu s o f institutiona l control s an dtarge t cleanu p goals . Thes e concerns hav e bee n addresse di n th e fina l report . Recommendatio n Th e selecte dremed y i s protectiv e o f huma n healt han dth e environment . Therefore , w e recommen dyo u sig n thi s five-yea r review . Contac t Person s Nanc y Smith , Wor k

Assignmen t

Manager , 918-143 6 Terrenc e Connelly , Remedia l Projec t Manager , 918-137 3 Attachment : Five-Yea r

Revie w Repor tRI02942 F 

### FIVE-YEA R REVIE W REPOR T FIVE-YEA R REVIE W O'CONNO R COMPAN Y SIT E AUGUSTA , MAIN E RESPONS E ACTIO N CONTRAC T (RAC) , REGIO N I Fo r 

### U.S . Environmenta l Protectio n Agenc y 

### B y Tetra Tec h NUS , Inc . EP AContrac

t No . 68-W6-004 5 EP AWor k

Assignmen t No . 123-FRFE-013 3 TtNU S Projec

t No . N425 4 Septembe r200 2

Phoeb e Apal l Georg e D(/Gardner , P.E . Project-Manage rProgra m Manage rTABL E O F CONTENT S FIVE-YEA R REVIE W REPOR T FIVE-YEA R REVIEW O'CONNO R COMPAN Y SIT E AUGUSTA , MAIN E SECTIO N PAG E ES- 1 EXECUTIV E SUMMAR Y E- 1 1. 0 INTRODUCTIO N 1- 1 2. 0 SIT E CHRONOLOG Y 2- 1 3. 0 BACKGROUN D 3- 1 3. 1 Physica l Characteristics 3- 1 3.1. 1 Settin g 3- 1 3.1. 2 Topograph y3- 1 3.1. 3 Subsurfac e Condition s 3- 1 3. 2 Lan d an d Resourc e Us e 3- 4 3. 3 Histor

yo f Contaminatio n 3- 5 3. 4 Initia l Respons e 3- 5 3. 5 Basi s fo rTakin g Actio n 3- 6 4. 0 REMEDIA L ACTION S 4- 1 4. 1 Remed ySelectio n 4- 1 4.1. 1 Sourc e Contro l 4- 1 4.1. 2 Managemen t of Migratio n 4- 2 4. 2 Remedia l Implementatio n 4- 3 4.2. 1 Source Contro l (OU-i ) 4- 3 4.2. 2 Managemen t o f Migratio n (OU-2 ) 4- 5 4.2. 3 Rigg s Broo k

(OU-3 ) 4- 7 4. 3 Syste m Operations/O& M 4- 7 5. 0 PROGRES S SINC E LAS T5-YEA R REVIE W 5- 1 6. 0 FIVE-YEA R REVIE W PROCES S 6- 1 6. 1 Administrativ e Component s 6- 1 6. 2 CommunityNotificatio n an d Involvemen t 6- 1 6. 3 Documen t Revie w6- 1 6. 4 Dat a Revie w6- 2 6.4. 1 Sourc e Contro l OU- 1 6- 2 6.4. 2 Managemen t o f Migratio n OU- 2 6- 2 6.4. 3 Rigg s Broo k

OU- 3 6- 4 6. 5 Sit e Inspectio n 6- 5 6. 6 Interviews . 6- 6

RI02942 F -j - Tetr a Tec h NUS , Inc .TABL E O F CONTENT S (Cont'd ) FIVE-YEA R REVIE W REPOR T FIVE-YEA R REVIE W O'CONNO R COMPAN Y SIT E AUGUSTA , MAIN E SECTIO N PAG E 7. 0 TECHNICA L ASSESSMEN T7- 1 7. 1 Questio n A : I s th e Remed yFunctionin g a s Intende d byth e Decisio n Documents ? 7- 1 7.1. 1 OU-1 : Sourc e Contro l Remedia l Actio n 7- 1 7.1. 2 OU-2 : Managemen t o f Migratio n 7- 3 7.1. 3 OU-3 : Rigg s Broo k 7- 4 7. 2 Questio n B : Are th e Exposure Assumptions , Toxicit yData , Cleanu p Level s an d Remedia l Actio n Objective s (RAOs ) Use d a t th e Tim e o f Remed ySelectio n Stil l Valid ? 7- 6 7.2. 1 OU-1 : Sourc e Contro l Remedia l Actio n 7- 6 7.2. 2 OU-2 : Managemen t o f Migratio n 7- 8 7.2. 3 OU-3 : Rigg s Broo k 7-1 0 7. 3 Questio n C : Ha s An yOthe rInformatio n Com e t o Ligh t Tha t Coul d Cal l int o Questio n th e Protectivenes s o f th e Remedy ? 7-1 1 7.3. 1 OU-1 : Sourc e Contro l Remedia l Actio n 7-1 1 7.3. 2 OU-2 : Managemen t o f Migratio n 7-1 1 7.3. 3 OU-3 : Rigg s Broo k 7-1 2 7. 4 Technica l Assessmen t Summar y7-1 2 7.4. 1 OU-1 : Sourc e Contro l Remedia l Actio n 7-1 2 7.4. 2 OU-2 : Managemen t o f Migratio n 7-1 3 7.4. 3 OU-3 : Rigg s Broo k 7-1 3 8. 0 ISSUE S 8- 1 9. 0 RECOMMENDATION S AN D FOLLOW-U P ACTION S 9- 1 10. 0 PROTECTIVENES S STATEMENT S 10- 1 11. 0 NEX

TREVIE W 11- 1 TABLE S NUMBE R PAG E 2- 1 Chronolog yo f Sit e Event s 2- 1 3- 1 Contaminant s o f Concer n At Sit e 3- 8 4- 1 Annua l Syste m Operations/O& M Cost s - OU- 1 4- 9

RI02942 F -II - Tetra Tec h NUS , Inc .TABL E O F CONTENTS (Cont'd ) FIVE-YEA R REVIE W REPOR T FIVE-YEA R REVIE W O'CONNO R COMPAN Y SIT E AUGUSTA , MAIN E FIGURE S NUMBE R PAG E 3- 1 Sit e Locatio n Ma p 3- 2 3- 2 Sit e Feature s 3- 3 4- 1 Sit e Pla n 4- 4 APPENDICE S ADocumen t Revie wList/Reference s B Sit e Inspectio n Report C Sit e Intervie wList D ARAR s an d TBC s E Declaratio n O f Restrictiv e Covenan t An d Ma p Showin g Are a Covere d B y Covenan t F MEDE P Comments , date d Augus t 9 , 2002 , o n th e Draf t Fiv e Yea rRevie wReport

RI02942 F -jji - Tetra Tec h NUS , Inc .ACRONYM S

AO C Administrativ e Orde rb yConsen t ARA R Applicabl e o rRelevan t an d Appropriat e Requiremen t AWQ C Ambien t Wate rQualityCriteri a C D Consen t Decre e CERCL AComprehensiv e Environmenta l Response , Compensation , an d Liabilit yAct CF R Cod e o f Federa l Regulation s CM P Centra l Main e Powe rCompan y CM R Cod e o f Main e Rule s cPAH s carcinogeni c polyaromati c hydrocarbon s CS F Cance rSlop e Facto r CW AClea n Wate rAc t ES D Explanatio n o f Significan t Difference s H Ahealt h advisor y IEUB KIntegrate d Exposur e Uptak e Biokineti c Mode l IRI S Integrate d Ris k Informatio n Syste m MC L Maximu m Contaminan t Leve l MEDE P Main e Departmen t of Environmenta l Protectio n MEG s Maximu m Exposur e Guideline s MO M Managemen t of Migratio n MRSAMain e Revise d Statute s Annotate d M W Monitorin g Wel l NC P Nationa l Contingenc yPla n N D no n detec t NEP ANationa l Environmenta l Polic yAc t NOA ANationa l Oceani c an d Atmospheri c Administratio n NP L Nationa l Prioritie s List NRP ANatura l Resource s Protectio n Actio n O U Operabl e Uni t O& M Operation s an d Maintenance PCB s Polychlorinate d biphenyl s pp b part s pe rbillio n pp m part s pe rmillio n PR P Potentiall yResponsibl e Party

RI02942 F Tetra Tec h NUS , Inc .ACRONYM S (Cont'd )

RAG S Remedia l Actio n Guideline s RA O Remedia l Actio n Objective s RfD s USEP ARis k Referenc e Dose s RI/F S Remedia l Investigation/FeasibilityStud y RO D Record o f Decisio n R P Responsibl e Part y RSO W Remedia l Design/Remedia l Actio n Revise d Statemen t o f Wor k SAR ASuperfun d Amendmen t Reauthorizatio n Ac t S C Sourc e Contro l SCR ASourc e Contro l Remedia l Actio n SDWASaf e Drinkin g Wate rAct Sit e O'Conno rCompan ySuperfun d Site SO W Statemen t o f Wor k TB C To B e Considere d T l Technica l Impracticabilit y TtNU S Tetr a Tec h NUS , Inc . TSC AToxi cSubstance s Contro l Act TWATransforme rWor k Are a ug/L microgram s pe rlite r USEPAUnite d State s Environmenta l Protectio n Agency VE R vacuu m enhance d recover y VO C volatil e organi ccompoun d W& C Woodard & Curra n Inc .

RI02942 F -II - Tetra Tec h NUS , Inc .EXECUTIV E SUMMAR Y

Afive-yea rrevie w wa s performe d fo rth e F . O'Conno rSuperfun d Sit e i n Augusta , Maine , a s require d b yCERCL

Awhe n hazardou s wast e i s lef t onsite , whic h doe s no t allo w unrestricte d us e o f a site . Th e purpos e o f th e five-yea rreview wa s t o asses s whethe rth e remed yselecte d fo rth e Sit e remain s protectiv e o f huma n healt h an d th e environment . Th e 198 9 Recor d o f Decisio n selecte d a remed yt o addres s th e risks presen t a t th e Sit e resultin g fro m th e operatio n of a salvag e an d electrica l transforme rrecyclin g business . Th e remed yfo rth e O'Conno rSuperfun d Sit e (Site ) consist s o f thre e operabl e unit s (OUs) . Th e Source Contro l remed y(OU-1 ) specifie d i n th e 198 9 Record of Decisio n (ROD ) was change d i n a n Explanatio n of Significan t Difference s (ESD) i n 1994 . Th e Sourc e Contro l remedia l actio n include d excavatio n an d of f sit e disposa l o f soil s an d sediment s tha t exceede d targe t cleanu p levels , implementatio n of institutiona l controls , treatmen t of surfac e waters o n th e Sit e an d sit e restoration . Restoratio n activitie s include d installatio n o f a vegetate d cove rove rth e excavate d area s an d reconstructio n of wetlan d areas . Th e Source Contro l remedia l actio n wa s complete d o n Novembe r11 , 1997 . Th e trigge rfo rthi s five-yea rrevie w wa s th e start o f sourc e contro l activitie s i n Augus t 1996 . Th e Managemen t o f Migratio n (MOM ) remed yi s separate d int o OU- 2 fo rgroundwate ran d OU- 3 fo rRigg s Broo k

sediment . Th e OU- 2 activitie s are ongoin g an d consist of institutiona l controls , oi l recovery , an d groundwate rmonitoring . Vacuu m enhance d recover yo f residua l oi l fro m th e Transforme rWor k

Are a (TWA) I I are a ha s bee n use d t o remov e fre e oi l fro m groundwate r monitorin g wells . Groundwate rwell s aroun d th e perimete rof th e Sit e meet th e targe t cleanu p goals . Concentration s o f VOC s an d PCB s i n groundwate rmeet th e targe t cleanu p goal s throughou t mos t of th e Site . Th e OU- 3 remed yincludes te n years of annua l monitorin g of Rigg s Broo k sedimen t an d periodi c biot a sampling . Biot a result s hav e bee n belo w th e targe t level ; sedimen t results hav e show n sporadi c exceedance s of th e PC B threshol d leve l that woul d trigge ra n evaluatio n o f th e nee d fo rfurthe rremedia l action . Th e five-yea rrevie w proces s reveale d that th e remedie s fo ral l thre e operabl e units hav e bee n implemente d i n accordanc e wit h th e requirement s o f th e ROD , a s modifie d b yth e ES D an d contingenc

yremedy . Th e remed yfo rOU- 2 i s not protectiv e i n th e TW A II/T I zon e of th e Site . A RO D amendmen t i s underwayt o addres s th e issue s covere d i n th e T l Waiver . Excludin g th e TW AI I area , th e remed yi s functionin g a s designed . A restrictive covenan t signe d byCentra l RI02942 F E- 1 Tetr a Tec h NUS , Inc .Main e Powe r(CMP ) an d MEDE P i n 199 4 restrict s certai n action s o n th e Sit e withou t writte n

approva l fro m MEDEP . Althoug h thi s covenan t i s hel d i n escro wb yMEDE P an d therefor e there i s som e questio n a s t o it s enforcement , CM P ha s complie d wit h th e restriction s an d consequently , th e threat t o exposur e t o contaminate d groundwate rha s bee n prevented . Achievemen t of groundwate rcleanu p goal s i n th e TW AI I are a wil l b e addresse d i n th e RO D amendmen t an d revise d Consen t Decree/Statemen t of Wor k (CD/SOW) . Five-Yea rRevie wProtectivenes s Statements :

• OU-1 : Th e remedia l actio n fo rOU- 1 ha s bee n complete d an d i s protectiv e o f huma n healt h an d th e environment . Exposure pathway s tha t coul d resul t i n unacceptabl e ris k are bein g controlled . Th e finalizatio n o f th e O& M pla n wil l ensur e that th e OU- 1 remed y wil l remai n protective .

• OU-2 : Th e remed yat OU- 2 i s protectiv e o f portion s o f th e Site . I t i s no t protectiv e o f th e TW AI I are a an d surrounding s a s define d a s th e T l Zon e i n th e T l Waive rdu e t o th e presenc e of residua l oi l i n th e subsurfac e an d PC B an d VO C concentration s tha t ca n not meet targe t cleanu p levels . Action s now underwa yt o implemen t th e T l Waive rare neede d t o ensur

e protectiveness .

• OU-3 : Th e remed yat OU- 3 i s expecte d t o b e protectiv e o f huma n healt h an d th e environmen t upo n completio n of th e 10-yea rsamplin g program . I n th e interim , exposure pathway s that coul d resul t i n unacceptabl e risks are bein g monitored . Curren t dat a indicat e that PC B concentration s i n th e sediment s o f Rigg s Broo k are slightl yabov e th e trigge rleve l i n isolate d an d sporadi coccurrences .

RI02942 F E- 2 Tetra Tec h NUS , Inc .Five-Yea r ReviewSummary For m

SIT E IDENTIFICATIO N Sit e nam e (from

WasteLAN):

O'Conno r Co . EP A I D (from

WasteLAN):

MED980731475 Region : 1 SIT E STATU S State : M E [ City/County : Augusta/Kennebe c NP L status : Fina l Remediatio n statu s (choos e al l tha t apply) : Operatin g (OU2&OU3 ) Complet e (OU1 ) Multipl e OUs? * YE S Constructio n completio n date : Ha s sit e bee n pu t int o reuse ? N O REVIE W STATU S Lea d agency : EP A Autho r name : Terrenc e Connell y Autho r title : Remedia l Projec t Manage rAutho r affiliation : EP A Regio n I Reviewperiod:* * 3/1/02 t o 9/30/0 2 Date(s ) of site inspection : 5/21/0 2 Typ e o f review : Post-SAR A Revie wnumber : 1 (first ) Triggerin g action : OU 1 Commencemen t o f SCR A Triggerin g actio n dat e (from WasteLAN):

7/30/199 6 Du e dat e (five

years after triggering

action date): 7/30/01** *

* "OU " refers t o operabl e unit . * * [Reviewperio d shoul d correspon d t o th e actua l star t an d en d date s of th e Five-Yea rRevie w i n WasteLAN. ] ** * Th e five-yea rrevie wwa s schedule d t o begi n i n Augus t 200 1 bu t wa s delaye d unti l Januar y 200 2 du e t o a chang e i n EP Aproject managers .

RI02942 F E- 3 Tetra Tec h NUS , Inc .Five-Yea r Revie wSummary Form , cont'd .

Issues :

• OU- 2 cleanu p goal s no t achievabl e i n TW AI I area . • Rigg s Broo k

sediments hav

e not attaine d targe t cleanu p levels . • Shortfal l i n wetlan d restoratio n acreage . • 199 2 ME G fo rPCB s lowe rtha n RO D targe t cleanu p leve l fo rPCBs . • Reevaluat e groundwate rus e restrictions . Recommendation s an d Follow-u p Actions :

• Amen d RO D t o reflec t T l Waive ran d change s t o OU- 2 ARARs . • Continu e sedimen t monitorin g progra m pe rROD . • Continu e wetlan d monitoring . • Analyz e groundwate rat lowe rPC B D L t o evaluat e i f Sit e ca n attai n lowe r199 2 MEG . • Restructure Institutiona l Control s fo rlong-ter m protectiveness . Protectivenes s Statement(s) : OU-1 : Th e remedia l actio n fo rOU- 1 ha s bee n complete d an d i s protectiv e o f huma n healt h an d th e environment . Exposure pathway s that coul d resul t i n unacceptabl e ris k are bein g controlled . Th e finalizatio n o f th e O& M pla n wil l ensur e that th e OU- 1 remed ywil l remai n protective . OU- 2 : Th e remed yat OU- 2 i s protectiv e i n portion s o f th e Site . I t i s no t protectiv e i n th e TW A I I are a an d surrounding s define d a s th e T l Zon e i n th e T l Waive rdu e t o th e presenc e o f residua l oi l i n th e subsurfac e an d PC B an d VO C concentration s that ca n no t mee t targe t cleanu p levels . Action s no wunderwa yt o implemen t th e T l Waive rar e neede d t o ensur e protectiveness . OU-3 : Th e remed yat OU- 3 i s expecte d t o b e protectiv e o f huma n healt h an d th e environmen t upo n completio n of th e 10-yea rsamplin g program , an d i n th e interim , exposur e pathway s that coul d resul t i n unacceptabl e risk s are bein g monitored . Curren t dat a indicate s that PC B concentration s i n th e sediment s of Rigg s Broo k are slightl yabov e th e trigge rleve l i n isolate d an d sporadi coccurrences . Othe r Comments :

RI02942 F E- 4 Tetr a Tec h NUS , Inc .1. 0 INTRODUCTIO N

Th e purpos e o f thi s five-yea rrevie wi s t o determin e i f th e remed yselecte d fo rth e F . O'Conno r Superfun d Sit e (Site ) i n Augusta , Maine , i s protectiv e o f huma n healt h an d th e environment . Thi s repor

t summarize s th e five-yea rreviewprocess , investigation s an d remedia l action s undertake n at th e Site , evaluate s th e monitorin g dat a collected , discusse s an yissue s identifie d durin g th e review , an d present s recommendation s t o addres s them . Th e Unite d State s Environmenta l Protectio n Agency , Regio n 1 (USEPA ) i s preparin g thi s five yea rreviewpursuan t t o th e Comprehensive Environmenta l Respons e Compensation , an d Liabilit yAct (CERCLA ) §12 1 an d th e Nationa l Contingenc yPla n (NCP) . CERCLA§12 1 states : "I f th e Presiden t select s a remedia l actio n that result s i n an yhazardou s substances , pollutants , o rcontaminant s remainin g at th e site , th e Presiden t shal l revie wsuc h remedia l actio n n o les s ofte n tha n eac h fiv e year s afte rth e initiatio n o f suc h remedia l actio n t o assure tha

t huma n healt h an d th e environmen t ar e bein g protecte d byth e remedia l actio n bein g implemented . I n addition , i f upo n suc h revie wi t i s th e judgmen t of th e Presiden t tha t actio n i s appropriat e at suc h sit e i n accordanc e wit h sectio n [104 ] o r [106] , th e Presiden t shal l tak e o rrequire suc h action . Th e Presiden t shal l repor t t o th e Congres s a lis t o f facilitie s fo rwhic h suc h revie wi s required , th e result s o f al l suc h reviews , an d an yaction s take n a s a resul t o f suc h reviews. " Th e USEP Ainterprete d thi s requiremen t furthe ri n th e Nationa l Contingenc yPlan ; 4 0 CF R §300.430(f)(4)(ii ) states : "I f a remedia l actio n i s selecte d that result s i n hazardou s substances , pollutants , o r contaminant s remainin g a t th e sit e abov e level s tha t allo wfo runlimite d us e an d unrestricte d exposure , th e lea d agencyshal l revie wsuc h actio n n o les s ofte n tha n every fiv e year s afte rth e initiatio n o f th e selecte d remedia l action. " Th e remed yfo rth e Sit e wa s separate d into thre e operabl e units : • OU- 1 Sourc e Contro l • OU- 2 Managemen t o f Migratio n • OU- 3 Rigg s Broo k Th e Sourc e Contro l Remedia l Actio n (SCRA ) a t OU- 1 wa s complete d i n Novembe r1997 . Remedia l action s a t OU- 2 an d OU- 3 ar e ongoing . Arevie wo f al l thre e operabl e units i s include d i n thi s report .

RI02942 F 1- 1 Tetra Tec h NUS , Inc .Thi s i s th e firs t five-yea rrevie wfo rth e O'Conno rCompan ySite . Th e triggerin g actio n fo rthi s

statutor yrevie wi s th e commencemen t o f SCR Aactivitie s i n Augus t 1996 . Action s relate d t o OU- 2 (MOM ) an d OU- 3 (Rigg s Brook ) commence d i n Octobe r1996 . Th e five-yea rrevie wi s require d sinc e contaminatio n remain s a t th e Sit e abov e level s that allo wfo runrestricte d us e an d exposure . Th e five-yea rrevie wwa s schedule d t o begi n i n Augus t 200 1 bu t wa s delaye d unti l Januar y200 2 du e t o a chang e i n EP Aproject managers . EP Aha s conducte d thi s five-yea rrevie wo f th e remedia l action s implemente d a t th e O'Conno r Sit e i n Augusta , Maine . Tetr a Tec h NUS , Inc . (TtNUS ) supporte d USEP Ai n completio n o f th e revie wunde rRAC I Contract No . 68-W6-0045 , W.A . No . 123-FRFE-0133 . Th e wor k assignmen t bega n i n Marc h 200 2 an d wil l b e complete d i n Octobe r2002 . Assistanc e wa s provide d b yth e Main e Departmen t o f Environmenta l Protectio n (MEDEP) , Centra l Main e Powe rCo . (CMP ) an d Woodard & Curran , Inc . (W&C) , consultant s workin g fo rCMP . A s reference d i n th e 199 1 Consen t Decree , CM P participate d i n th e five-yea rrevie wprocess . W& C o n behal f o f CM P provide d draft portion s o f th e Five-Yea rRevie wRepor t t o USEPA . W& C complete d draft portion s o f th e repor

t betwee n Januar

yan d Apri l 2002 . Th e revie wwa s complete d i n accordanc e wit h USEP AGuidanc e OSWE R No . 9355.7-03B-P .

RI02942 F 1- 2 Tetr a Tec h NUS , Inc .2. 0 

### SIT E CHRONOLOG Y TABL E 2- 1 CHRONOLOG Y O F SIT E EVENTS FIVE-YEA R REVIE W REPOR T O'CONNO R COMPAN YSIT E AUGUSTA , MAIN E 

### DAT E Earl y1950 s Feb197 2 1 97 8 & 198 2 1982-198 4 Sept8 , 198 3 De c21 , 198 4 Apri l 198 5 Ma y13 , 198 6 Ma y19 , 198 6 Jun e 23 , 198 6 Ma y23 , 1987 Jun e 15 , 198 9 Sep t 27 , 198 9 SeptS , 199 1 Jun e 199 4 Jul y11 , 1994 Oct20 , 199 4 Octobe r10 , 199 5 Jul y199 6 Au g - Oc

t 1 99 6 Oct199 6 Oc t 1996 Ja n -Ma y199 7 May-No v199 7 Nov . 11 , 199 7 Au g - Oct 200 1 Apri l 200 2 Augus t 200 2 

### EVEN T

F . O'Conno rCo . begin s operatin g a salvag e an d electrica l transforme rrecyclin g busines s o n th e site . Oi l spil l o n sit e foun d t o hav e migrate d towar d Rigg s Brook . MEDE P conduct s additiona l samplin g event s a t th e site , identifie s polychlorinate d bipheny l (PCB ) contamination . USEP Aconduct s samplin g event s a t th e site , confirm s PC B contamination . Sit e place d o n Nationa l Prioritie s List (NPL ) USEP Aissue s Unilatera l Administrativ e Orde rt o O'Conno rCo . requirin g i t t o fenc e 5 acre s o f th e Sit e an d sampl e an d analyz e al l drum s an d tank s o n th e site . USEP Anotifie s O'Conno ran d Centra l Main e Powe ro f thei rpotentia l responsibility fo rcontaminatio n a t th e Site . O'Conno ran d CM P voluntaril yente rint o a n Administrativ e Orde rb yConsen t (AOC ) wit h USEP At o conduct a Remedia l Investigatio n an d Feasibilit yStud y (RI/FS ) a

t th e Site . MEDE P issue s a n Administrativ e Orde rt o O'Conno rdesignatin g th e Sit e a n Uncontrolle d Hazardou s Substance Sit e unde rMain e law . MEDE P issue s a n AO C t o O'Conno ran d CM P USEP Aan d MEDE P issu e a n amende d AO C t o O'Conno ran d CMP . Orde r extend s Sit e limits t o approximatel y9 acres . CM P submits a draft RI/F S t o USEPAan d MEDE P fo rreview . RO D issue d b yUSEPA . C D betwee n USEP

Aan d CM P signed . MEDE P an d CM P sig n a Declaratio n o f Restrictiv e Covenant . ES D signed . Revise d Statemen t o f Wor k (RSOW ) issue d USEP Ainvoke s th e contingenc yremedy . Sourc e Contro l 100 % Desig n complete d Phas e I o f Sourc e Contro l complete d (OU-1 ) Firs t samplin g o f OU-3 , Rigg s Broo k sedimen t Phas e I Vacuu m Enhance d Recover y(VER) (pilot

) complete d (OU-2 ) Phas e I I VE R complete d (OU-2 ) Phas e I I of Sourc e Contro l complete d (OU-1 ) Sourc e Contro l Remedia l Actio n complete d Phas e II I VE R complete d (OU-2) Draf t T l Evaluatio n Repor t submitte d t o USEP Aan d MEDE P fo rOU- 2 Managemen t of Migration . Completio n o f First Five - Yea rRevie w

RI02942 F 2- 1 Tetr a Tec h NUS , Inc .3. 0 BACKGROUN D

3. 1 Physica l Characteristic s 3.1. 1 Settin g Th e F . O'Conno rSuperfun d Sit e propertyconsist s o f approximatel y2 3 acre s withi n a 28-acr e propertyan d i s locate d o n U.S . Rout e 1 7 approximatel ythre e mile s eas t o f th e Kennebe cRive r i n Augusta , Maine . Th e surroundin g are a i s generall yrural . Th e propertyi s bordere d o n th e eas t an d southeas t b yRigg s Brook , a smal l northerl yflowin g tributar yo f th e Kennebe cRiver , o n th e nort h an d wes t b ywoodlands , an d o n th e sout h b yRout e 17 . Th e propert ysout h o f Rout e 1 7 i s generall ywooded . Aresidenc e abut s th e CM P propertyalon g it s wester n boundary . Th e lan d at th e Sit e wa s use d a s farmlan d unti l th e 1950 s whe n th e F . O'Conno rCompan y establishe d a salvag e yar d an d transforme rrecyclin g operatio n a t th e Site . Th e MEDEP designate d Hazardou s Substanc e Sit e consist s o f th e sam e 2 3 acre s withi n th e 28-acr e property . Th e locatio n of th e propertyi s show n o n Figur e 3-1 . 3.1. 2 Topograph y Th e Sit e i s locate d o n a ridg e tha t transect s th e Sit e i n a generall ynortheast-southwest direction . A n acces s roa d splits th e Site fro m southwest t o northeast . Nort h an d wes t of th e road , th e Sit e i s relativel ylevel , wit h a low swampyare a know n a s th e Uplan d Marsh . Eas t an d sout h of th e roa d th e topograph yslope s sharpl ytoward Rigg s Brook , wit h a chang e i n elevatio n o f approximatel y5 0 feet . Thre e wate rbodie s ar e locate d o n th e Site , al l o f whic h wer e create d b yoperation s o f th e F . O'Conno rCo . an d late rreconstructe d durin g th e SCRA . Th e approximatel y2-acr e Uplan d Mars h drain s t o a channe l tha t flow s t o th e Uppe ran d Lowe r Lagoon s an d o n t o th e Rigg s Broo k wetlands . Figure 3- 2 show s thes e feature s an d Sit e topography . 3.1. 3 Subsurfac e Condition s Th e overburde n soil s a t th e Sit e generall yconsist , fro m surfac e t o depth , o f glacia l marin e silt s an d clays , glacia l till , an d bedrock . Th e cla ytend s t o b e absen t onl yi n area s o f shallow bedrock . Durin g sourc e control , approximatel y20,00 0 ton s o f soi l an d sedimen t wit h PC B concentration s greate rtha n 1 0 pp m wer e excavate d an d dispose d offsite . Anothe r3,00 0 tons , RI02942 F 3- 1 TetraTechNUS , Inc .FEE T SOURCE : WOODWAR D & CURRAN SIT E LOCATIO N MA P FIGUR E 3- 1 O'CONNO R COMPAN Y SUPERFUN D SIT E - FIVE-YEA R REVIE W AUGUSTA , MAIN E DRAW N B YD. W MACDOUGAL L CHECKE D B Y P CAL L SCALE . A S NOTE D RE V 

### TETR ATEC H NUS , INC . DATE . JUL

Y 5 , 200

2 NAME . DWG\4254\0600\FIG_3- 1 DWG 5 5 Jonspi n Road Wilmington , M A0188 7 (978)658-789 9

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## ywit h PC B level s les s tha n 1 0 ppm , wer e consolidate d onsit e i n on e area , identifie d a s th e

Designate d Are a (se e Figure 3-2) . Approximatel y24,00 0 cubi cyard s o f clea n soi l (PCB s les s tha n 1 ppm ) wer e importe d t o th e Sit e t o restor e th e excavate d are a t o approximat e th e origina l grad e an d t o provid e a 12-inc h soi l cove rove rth e entir e Designate d Area . Bedroc k drillin g complete d durin g sit e investigation s indicate d mostl ycompeten t roc k wit h very fe wrecognizabl e fractures . Bedroc k outcrop s ar e foun d i n th e area s o f transforme rwor k are a (TWA ) I an d II I (se e Figure 3-2) . Th e principa l groundwate rmigratio n pathwa yo n th e Sit e i s a discret e zon e withi n th e til l alon g th e to p o f th e bedroc k surface . Groundwate rflo wfro m th e Uplan d Mars h ( a larg e recharg e basin ) i s confine d an d channele d throug h th e bedroc k troug h i n th e bedroc k

saddl e centere d immediatel ynortheas t o f th e Uppe rLagoon . Th e bedroc k flo wregim e ha s verylittl e wate ri n storage . Th e vertica l permeabilityo f th e bedroc k i s believe d t o b e verylow , creatin g a "quasi " perche d conditio n o f th e overburde n groundwate rflo wsystem . At th e southeaster n en d o f th e Site , nea rRigg s Brook , th e potentiometri csurfac e o f th e bedroc k groundwate ri s abov e th e groun d surface . MW-106 B i n thi s are a i s a free-flowin g artesia n well . (W&C , 2000) . 3. 2 Lan d an d Resourc e Us e Th e Sit e i s currentl ya mi xo f fores t an d ope n field , borderin g th e Rigg s Broo k wetland . Th e ope n field s encompas s th e formerl ycontaminate d area s an d th e thre e reconstructe d wetland s o n th e Sit e (Uplan d Marsh , Uppe rLagoon , an d Lowe rLagoon) . Th e Sit e i s n o longe rsecure d wit h perimete rfencin g an d i s no t activel yuse d b yCMP . Surroundin g lan d use s includ e low densityresidential , ligh t agricultural , fields , an d forest . Curren t zonin g map s an d lan d us e ordinance s wer e obtaine d fro m th e August a CityService s Department . Th e uplan d portio n o f th e Sit e i s zone d a s RRE S - rura l residentia l district , wher e residentia l developmen t that conserve s th e rura l characte ro f th e are a i s permitted . Th e portio n o f th e Sit e tha t slope s dow n towar d Rigg s Broo k

i s zone d L R - limite d residentia l district . Th e L R district i s suitabl e fo r residentia l an d recreationa l development . Th e wetlan d are a that surround s Rigg s Broo k i s zone d R P - resourc e protectio n district , wher e developmen t woul d adversel yaffect wate r quality , productiv e habitat , biologica l ecosystems , o rarea s wit h sceni can d natura l values . (City of Augusta , M E Lan d Us e Ordinance )

RI02942 F 3- 4 TetraTechNUS , Inc .Natura l resource s o n th e O'Conno rpropert yinclud e bot h terrestria l an d aquati chabitats . Rigg s Broo k i s no t navigabl e i n th e vicinityo f th e Site , bu t larg e wetlan d area s i n th e Rigg s Broo k watershe d hav e bee n mappe d b yth e MEDEP . Th e Rigg s Broo k wetland s are considere d t o b e shru b swamps , consistin g o f a mi xo f woodland s an d emergen t aquati cvegetatio n an d peat . N o rar e o rendangere d specie s hav e bee n identifie d i n wetlan d o rwoodlan d habitat s associate d wit h th e Site . Th e Rigg s Broo k wetland s li e i n a Zon e Aaccordin g t o th e Cityo f August a Floo d Insuranc e Rat e Ma p (23006 7 001 1 C) , revise d Jun e 15 , 1994 . Zon e Ai s a specia l floo d hazard are a inundate d b y100-yea rfloo d wher e n o bas e floo d elevation s hav e bee n determined . There ar e n o othe rspecifie d floo d hazar d zone s coverin g th e balanc e o f th e Site . Ther e ar e n o mappe d san d o rgrave l aquifer s i n th e vicinityo f th e Site . Bedroc k well s wer e historicall yuse d fo rdomesti cwate ri n th e area , howeve rpubli c wate ri s no wavailabl e throughou t th e area . 3. 3 Histor

y of Contaminatio n Th e F . O'Conno rCompan yoperate d a salvag e yar d fo rth e dismantlin g an d recyclin g o f electrica l transformers an d capacitor s o n th e Site fro m th e earl y1950s unti l th e lat e 1970s . Thi s resulte d i n drippag e an d spillag e o f oi l t o th e ground , principall yi n th e vicinityo f th e transforme r wor k area s (TWAs) . Soi l an d groundwate rcontaminatio n primaril yconsiste d o f PCB s wit h som e volatil e an d semi-volatil e organi ccompounds , an d inorganics . Potentia l source s o f contaminatio n tha t wer e identifie d o n th e Sit e include d thre e TWAs , scra p piles , oi l storag e tanks , an d tw o lagoon s installe d t o hel p contro l oi l migratio n fro m thi s Site . 3. 4 Initia l Respons e Th e firs t repor

t o f contaminatio n wa s du e t o a n oi l spil l o n th e Sit e i n Februar y1972 , whic h wa s investigate d b yMEDEP . Late rthat yea rMEDE P requeste d th e O'Conno rCompan ycontai n al l transforme rfluid s i n abov e groun d storag e tank s t o preven t spills . I n 1976 MEDE P conducte d furthe rinvestigation s at th e Site , an d aske d th e O'Conno rCompan y t o construc

t two surfac e wate rlagoon s o n th e Sit e t o contro l migratio n o f oils . Th e nex t year , MEDE P requeste d that th e Compan ydiscontinu e us e o f th e lagoon s an d reclai m th e area . Wate rfro m th e lagoon s wa s pumpe d int o storag e tanks an d th e sediment s wer e excavate d an d

RI02942 F 3- 5 Tetr a Tec h NUS , Inc .place d i n a lo ware a nea rth e grave l acces s road . Th e sediment s wer e underlai n an d covere d

b yone-foo t o f claysoil . Placemen t o f thi s soi l create d a barrie rt o surfac e wate rrunoff , an d resulte d i n th e creatio n o f th e Uplan d Marsh . Th e Sit e wa s propose d fo rinclusio n o n th e NP L i n Decembe r1982 , an d place d o n th e fina l NP L o n Septembe r8 , 1983 . I n Apri l o f 198 5 th e F . O'Conno rCompan yan d CM P wer e notifie d o f thei rpotentia l liabilit

yfo rth e site . CM P complete d severa l additiona l respons e activitie s includin g placemen t o f a chai n lin k fenc e aroun d th e Sit e i n 1985 , removin g th e abov e groun d storag e tank s i n 1986 , an d extendin g th e chai n lin k

fenc e an d removin g ove r50 0 ton s o f materia l fro m th e scra p are a i n 1987 . Followin g completio n o f a n RI/F S i n 1989 , th e RO D wa s fo rth e Sit e wa s issue d o n Septembe r 27 , 1989 . CMP , a n identifie d Potentiall yResponsibl e Party(PRP ) at th e site , signe d a Consen t Orde rwit h th e USEP Ao n Septembe r3 , 199 1 t o undertake a n investigatio n an d remediatio n o f th e site . CM P als o acquire d ownershi p o f th e Sit e fro m th e F . O'Conno rCo . i n 1992 . 3. 5 Basi s fo r Takin g Actio n Th e hazardou s substance s that hav e bee n release d t o th e Sit e ar e primaril yrelate d t o PC S oil s an d scra p fro m th e dismantlin g o f transformers . Base d o n th e compound s detecte d o n th e Sit e durin g th e Rl , contaminant s o f concer n wer e identified . Thes e contaminant s o f concer n wer e liste d i n Tabl e 1 o f th e ROD , an d are provide d i n th e firs t colum n o f Tabl e 3- 1 o f thi s report . A s discusse d i n th e ROD , a n Endangermen t Assessmen t wa s performe d t o estimat e th e potentia l advers e huma n healt h an d environmenta l effect s fro m exposur e t o th e contaminant s o f concern . Th e majo rconclusion s draw n fro m th e Endangermen t Assessmen t ar e a s follows :

• Direc t contact with , ingestio n of , o rinhalatio n o f vapor s fro m soil s contaminate d wit h PCB s an d carcinogeni cpolyaromati chydrocarbon s (cPAHs ) maypos e a n incrementa l increas e i n cance rris k

ove ra lifetim e o f exposure . Childre n potentiall yplayin g o n th e Sit e currently , o rfutur e resident s livin g o n th e Sit e woul d b e at th e greates t risk . Lea d i n soil s ma yals o pos e a ris k o f adverse , non-carcinogeni chealt h effect s (throug h direc t contact an d ingestion ) b ypotentia l futur e resident s livin g at th e Site .

RI02942 F 3- 6 Tetra Tec h NUS , Inc .• A n increase d cance rris k ove ra lifetim e o f exposur e ma yals o b e associate d wit h direct contact an d ingestio n b ychildre n wit h th e PCB-contaminate d sediment s i n th e lagoon s locate d o n th e Site . • Ingestio n o f th e contaminate d groundwate rfro m th e deep/bedroc k syste m unde rth e Sit e maypos e potentia l long-ter m risks t o future inhabitant s o f th e Site . Contaminant s o f concer n are 1,4-dichlorobenzene , benzen e an d PCBs . • Environmenta l risk s t o biot a (i.e. , fish , wildlif e an d plants ) expose d t o contaminate d soils , sediments , o rsurfac e water s a t th e Sit e ma ypotentiall yexis t fro m th e presenc e o f PCBs , lea d an d aluminum . Base d o n th e result s o f th e Endangermen t Assessment , Applicabl e o rRelevan t an d Appropriat e Requirement s (ARARs ) an d othe rguidance , targe t cleanu p goal s (se e colum n 2 o f Tabl e 3-1 ) wer e establishe d t o protect huma n healt h an d th e environmen t fro m thes e identifie d risks . Th e RO D propose d a selecte d remed yfo rth e Sit e tha t woul d mee t thes e targe t cleanu p goals .

RI02942 F 3- 7 Tetr a Tec h NUS , Inc .

### TABL E 3- 1 CONTAMINANT S O F CONCER N AT SIT E FIVE-YEA R REVIE W REPOR T O'CONNO R COMPAN Y SIT E AUGUSTA , MAIN E Contaminant

s o f Concer n 1 

### Soi l PCB s CPAH s Lea d Cadmiu m Coppe r Nicke l Zin c Surfac e Wate r PCB s Lea d Aluminu m Groundwate r PCB s Benzen e 1 ,4-Dichlorobenzen e Bi s 2-ethylhexylpthalat e Chromiu m Manganes e On-Sit e Sedimen t PCB s CPAH s Lead Coppe r Manganes e Zin c Rigg s Broo k

Sedimen t PCB s Rigg s Broo k

Biot a PCB s Target Cleanu p Goa l z 

### 1 pp m 

### 1 pp m 24 8 pp m N A N A N A N A 

### 0.06 5 pp b 1.94pp b 8 7 pp b 0. 5 pp b 5 pp b 2 7 pp b N A N A N A 

### 1 pp m 

### 1 pp m 24 8 pp m 

### N A N A N A 

### 1 pp m 

### N A Selecte d Remedy 3 

### 1 pp m (DA=10ppm) 3 

### 1 pp m (DA=10ppm) 3 24 8 pp m N A N A N A N A 

### 0.06 5 pp b 1.9 4 pp b 8 7 pp b 0. 5 pp b 5 pp b 2 7 pp b N A N A N A 

### 1 pp m ( 5 ppm 4 

### ) 1 pp m 24 8 pp m N A N A N A 

### 1 ppm/ 5 pp m 5 

### 2 ppm 6 Notes : 1 . Base d o n Results o f th e Rl . 2 . Base d o n result s o f Endangermen t Assessment , ARARs , an d othe rguidance . 3 . Targe t cleanu p goa l fo rRO D (Septembe r1989 ) Selecte d Remedy , an d revise d b yES D (Explanatio n o f Significan t Difference s (Jul y20 , 1994)) . D A= Designate d Area . 4 . OU- 1 Are a 3 soil s nea rRigg s Broo k wetland . 5 . 1 pp m i s th e targe t cleanu p goal ; 5 pp m i s th e trigge rleve l fo rperformin g additiona l samplin g an d determinin g whethe r furthe rremedia l actio n i s necessary . RO D pg . 4 7 an d 52 ; Revise d SO W (Octobe r20 , 1994) , pg . 15 . 6 . RO D pg . 4 7 an d Revise d SO W pg . 15 . RI02942 F 3- 8 Tetra Tec h NUS , Inc .4. 0 REMEDIA L ACTION S

Thi s sectio n describe s th e remedia l action s selecte d fo ran d implemente d a t th e Site . 4. 1 Remed y Selectio n Th e Septembe r27 , 198 9 RO D fo rth e Sit e determine d that exposur e t o th e contaminate d medi a at th e Sit e maypresen t a n imminen t an d substantia l endangermen t t o publi c health , welfare , o r th e environmen t i f th e threat s wer e no t addresse d b ya respons e action . Aremed ywa s selecte d t o mee t th e followin g respons e objective s identifie d fo rth e Site :

• Reduce potentia l presen t an d future publi c healt h an d environmenta l risk s fro m direc

t contact , ingestion , and/o rderma l absorptio n wit h th e PCB- , cPAH- , an d lead contaminate d soil s an d sediments locate d on - an d off-site ; • Reduc e potentia l presen t an d futur e publi chealt h risk s fro m th e inhalatio n o f PC B vapors fro m th e Site ; • Reduc e potentia l presen t an d futur e publi chealt h risks fro m th e ingestio n o f PCB contaminate d fis h fro m Rigg s Brook ; • Reduc e potentia l futur e publi chealt h risks fro m th e ingestio n o f PCB- , benzene- , an d 1, 4 dichlorobenzene-contaminate d groundwate rfoun d o n th e Site ; an d • Reduc e potentia l presen t an d futur e environmenta l risks t o aquati can d terrestria l wildlif e fro m exposure s t o th e PCB- , lead- , an d aluminum-contaminate d on-sit e surfac e water . Th e remed yselecte d i n th e RO D include d component s fo rSourc e Contro l an d Managemen t o f Migration . 4.1. 1 Sourc e Contro l Th e Sourc e Contro l (OU-1 ) componen t o f th e remed yincluded :

• Excavatio n an d on-sit e treatmen t b ysolven t extractio n technolog yo f al l soi l an d sedimen t containin g concentration s o f PCB s an d cPAH s greate rtha n 1 pp m an d lea d greate rtha n 24 8 ppm ; • Drainin g an d off-sit e treatmen t o f al l surfac e water s o n th e Site ;

RI02942 F 4- 1 Tetra Tec h NUS , Inc .• Re-routin g o f existin g surfac e wate rdrainag e patterns ;

• Installatio n o f erosio n contro l measure s an d clearin g o f vegetation ; • Transportatio n an d off-sit e disposa l o f soi l an d sediment s shoul d solven t extractio n no t achiev e targe t cleanu p levels ; • Establishmen t o f compensator ywetlands ; • Sit e restoratio n followin g excavatio n activities ; • Five-yea rrevie wo f sit e conditions . O n Jul y11 , 1994 a n ES D wa s approve d an d appende d t o th e ROD . Base d o n a n assessmen t o f th e abilit

yt o implemen t th e RO D remedy , th e ES D adjuste d th e soi l targe t cleanu p goal s fo r al l soil s that woul d b e locate d more tha n 1 2 inche s belo wgrad e an d withi n a three - t o four-acr e Designate d Are a t o a maximu m 1 0 pp m PCB s an d cPAH s an d 24 8 pp m lead . Th e targe t cleanu p goal s fo rsoil s outsid e th e Designate d Are a remaine d a t 1 pp m PC B an d cPA H an d 24 8 pp m lea d (se e Colum n 3 o f Tabl e 3-1) . Th e ES D als o provide d fo ra contingenc yremed ythat allowe d soil s an d sediment s t o b e dispose d off sit e withou t solven t extractio n treatment , pendin g USEP Aapproval . O n Octobe r23 , 199 5 USEP Ainvoke d th e contingenc yremedy , base d upo n th e determinatio n tha t th e solven t extractio n treatmen t wa s no t feasibl e t o mee t th e targe t cleanu p goals . 4.1. 2 Managemen t o f Migratio n Th e MO M groundwate rcomponen t (OU-2 ) o f th e RO D selecte d remed yrequired :

• Establishmen t o f temporaryinstitutiona l control s unti l groundwate rremediatio n goal s ar e achieved ; • Installatio n o f groundwate rextractio n an d monitorin g wells ; • Installatio n o f a n on-sit e groundwate rtreatmen t an d recharg e system ; • Treatmen t an d recharg e syste m monitoring , operation , an d maintenance ; an d • Five-yea rrevie wo f sit e conditions . Th e MO M als o include d remedia l action s fo rRigg s Broo k sedimen t (OU-3) . Thes e included :

• Establishmen t an d implementatio n o f a n extensiv e sedimen t an d biot a samplin g an d analysi s progra m withi n Rigg s Brook ; RI02942 F 4- 2 Tetr a Tec h NUS , Inc .• Implementatio n o f publi ceducatio n programs ; an d

• Five-yea rrevie wo f sit e conditions . ARevise d Statemen t o f Wor k (RSOW ) wa s submitte d o n Octobe r20 , 199 4 an d appende d th e Consen t Decree . Th e RSOW define d th e remainin g wor k to b e complete d a

t th e Site an d finalize d th e targe t cleanu p goal s fo rth e MO M (se e Tabl e 3-1) . 4. 2 Remed y Implementatio n Activitie s complete d durin g th e implementatio n o f th e remedie s specifie d i n th e RO D are describe d i n thi s section . 4.2. 1 Sourc e Contro l (OU-1 ) Th e SCRA , OU-1 , wa s complete d i n tw o phases . Phas e I wa s conducte d i n th e summe ran d fal l o f 1996 an d include d decontamination , demolition , an d disposa l o f th e bar n an d othe rnon nativ e debris , remediatio n o f soil s closes t t o Rout e 17 ; an d constructio n o f th e suppor t are a fo r Phas e I I activities . Phas e I I bega n i n May1997 , an d th e SCR Awa s complete d o n Novembe r11 , 1997 . Phas e I I activitie s include d collectio n an d disposa l o f on-sit e surfac e waters , samplin g an d remediatio n o f soil s an d sediment s i n th e forme rTWA s an d th e remainde r o f OU-1 , reconstructio n o f th e Uppe rLagoon , Lowe rLagoo n an d th e Uplan d Mars h an d fina l restoratio n o f th e Site . Institutiona l control s limitin g acces s t o th e Sit e wer e include d i n th e for m o f a perimete rsit e fence . Approximatel y23,00 0 ton s o f soi l an d sedimen t wer e excavate d an d dispose d off-sit e o r consolidate d int

o th e Designate d Are a (se e Figur e 4-1 ) t o meet th e targe t cleanu p goals . As liste d i n Tabl e 3-1 , th e targe t cleanu p goal s fo rsoi l outsid e th e Designate d Are a wer e 1 pp m PCBs , 1 pp m cPAHs , an d 24 8 pp m lead ; an d 1 pp m PCB s fo ron-Sit e sediments i n th e vicinit y o f th e Rigg s Broo k

Wetlan d area . Targe t cleanu p goal s withi n th e Designate d Are a wer e 1 0 pp m PCBs , 1 0 pp m cPAH s an d 24 8 pp m lead . Soi l an d sedimen t sample s wer e collecte d usin g a samplin g gri d develope d t o provid e a statisticall yvali d approac h fo rconfirmin g tha t th e excavatio n ha d me t th e targe t cleanu p goals . Additiona l rando m sample s wer e collecte d a s determine d necessar

yi n th e fiel d t o confir m attainmen t o f targe t cleanu p goals .

RI02942 F 4- 3 Tetra Tec h NUS , Inc .UJ O

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PCBs , 1 pp m cPAH s an d 24 8 pp m lead ) wer e brough t on-sit e fo rre-grading . Th e entire Designate d Are a wa s covere d wit h 1 2 inche s o f clea n fil l t o ensure that , eve n i f thos e soil s contaminate d wit h betwee n 1 an d 1 0 pp m PCB s o rcPAH s withi n th e Designate d Are a were eve rdisturbe d b ypotentia l futur e activitie s a t th e Site , th e PC B an d cPA H level s a t th e surfac e woul d likel yb e les s tha n 1 pp m du e t o mixin g wit h th e clea n soil . Excavate d area s o f th e Sit e outsid e o f th e Designate d Are a wer e backfille d an d regraded . N o additiona l cove rwa s adde d i n th e area s outsid e th e Designate d Area . Sit e restoratio n include d re-establishin g drainag e pattern s t o achiev e discharge s t o Rigg s Broo k simila rt o thos e tha t existe d prio rt o remediatio n o f th e Site . I t als o include d restoratio n o f on sit e wetland s an d th e establishmen t o f approximatel y0. 4 acre s o f compensator ywetlands . Th e SCR Awa s complete d o n Novembe r11 , 1997 . 4.2. 2 Managemen t o f Migratio n (OU-2 ) Managemen t o f Migratio n remedia l action s fo rgroundwate rar e ongoin g an d includ e monitorin g groundwate rt o asses s th e potentia l fo rmigratio n o f contaminant s fro m th e Site . Investigation s complete d followin g th e RO D determine d tha t th e migratio n o f contaminant s i n th e shallo w groundwate ri n th e downgradien t directio n i s limited ; th e bedroc k aquife rha s lo wgroundwate r storag e an d therefor e a relativel ysmal l volum e o f water . I t wa s als o conclude d that th e 199 2 pum p tes t ha d mobilize d oi l an d othe rcontaminant s verticall ydownwar d int o th e bedroc k flo w regime . Base d o n thes e finding s th e R P contracto rrecommende d continue d groundwate r monitorin g an d th e us e o f vacuu m extractio n rathe rtha n conventiona l groundwate rpumping , t o eliminat e th e potentia l fo rdrawin g fre e floatin g produc t furthe rint o th e bedroc k aquife r(W&C , 2000) . Institutiona l control s wer e establishe d i n th e for m o f a Declaratio n o f Restrictiv e Covenan t signe d byMEDE P an d CMP . Thi s covenan t includes th e following :

• An yus e o f th e groundwate rbeneat h th e Sit e i s prohibite d withou t th e writte n approva l o f MEDEP ; • An yactivit

ywhic h migh t disrupt remedia l o rmonitorin g measure s i s prohibite d withou t th e writte n approva l o f MEDEP ; an d

RI02942 F 4- 5 Tetra Tec h NUS , Inc .• CM P o ran ysubsequen t owne rshal l maintai n th e Sit e i n a conditio n adequat e t o ensur e

th e continue d compliance wit h al l applicabl e standard s an d to ensur e th e ongoin g adequac yo f th e remediation . Thi s Covenan t ha s no t bee n recorde d an d i s currentl yhel d i n escro wb yMEDEP . Acop yo f th e covenan t an d a ma p showin g th e are a covere d b yth e covenan t are include d i n Appendi xE . Th e forma l MO M groundwater-monitorin g progra m bega n i n Octobe r199 5 usin g 1 5 of th e Sit e well s ( 7 overburde n an d 8 bedrock) . Anumbe ro f well s wer e remove d durin g soi l excavation ; ne wwell s hav e als o bee n added . Th e 16-wel l monitorin g networ k no wconsist s o f 1 0 overburde n an d 6 bedroc k wells . I n additio n t o th e MO M wells , fiv e well s i n th e forme rTW AI I are a ar e routinel ychecke d fo rth e presenc e o f residua l oil . Seepag e o f oi l int o th e TWAI I well s ha s bee n observe d sinc e oi l wa s firs t introduce d int o th e well s durin g th e 199 2 pum p test . Approximatel y29. 8 gallon s o f oi l wa s recovere d fro m thes e well s i n Octobe r1994 . AVE R syste m wa s applie d t o a n overburde n recover ywel l i n th e TWAI I are a i n 199 6 an d 1997 , removin g approximatel y26. 6 gallon s o f residua l oi l fro m th e till/bedroc k interface . Followin g th e completio n o f th e SCR Ai n 1997 , oi l seepag e int o th e well s decrease d significantly . Betwee n th e en d o f th e SCR Aan d th e summe ro f 2001 , approximatel y7. 1 gallon s o f oi l wa s recovere d fro m th e wells . Th e VE R Phas e II I wa s operate d i n th e fal l o f 200 1 an d remove d approximatel y19. 8 gallon s o f oil . Th e tota l amoun t o f oi l recovere d fro m th e fiv e TW AI I well s sinc e thei rinstallatio n i s approximatel y85. 2 gallons . (W&C , 2000 ; W& C 200 1 d) . To dat e th e MO M monitorin g progra m (well s outsid e TW AII ) has show n tha

t th e groundwate r meet s th e RO D targe t cleanu p goal s a t th e perimete ro f th e Site . Othe rgroundwate rmonitorin g well s sho wdecreasin g trend s fo rthos e compound s no t ye t a t th e cleanu p standard . Withi n th e TW AI I area , concentration s o f PCBs , benzene , an d 1,4-dichlorobenzen e excee d th e targe t cleanu p goals . Th e sourc e of thi s contaminatio n i n groundwate ri n th e TW AI I are a i s believe d t o b e th e residua l oi l trappe d i n th e crack s i n th e clayan d bedroc k fractures . Th e TWAI I are a well s ar e th e subject o f a n applicatio n fo ra Technica l Impracticability(Tl ) waive rbein g sough t b yCMP .

RI02942 F 4- 6 Tetra Tec h NUS , Inc .4.2. 3 Rigg s Broo k (OU-3 ) Th e 10-yea rRigg s Broo k sedimen t samplin g an d analysi s progra m bega n i n Octobe r1996 , an d ha s continue d o n a n annua l basi s everyfall . Ther e hav e bee n sporadi cexceedance s o f th e 5 pp m trigge rleve l fo rPCB s ove rtime , an d i n accordanc e wit h th e progra m describe d i n th e ROD , i n 199 7 tw o hot-spo t sedimen t area s wer e excavated . At EPA' s request , th e 200 0 annua l progra m wa s supplemente d wit h a samplin g gri d wit h 5 1 location s adjacen t t o Rigg s Broo k an d i n Area s 2 an d 3 of th e forme rSource Contro l are a of th e Site . Fou rlocation s exceede d th e Rigg s Broo k

trigge rleve l fo rPCB s o f 5 ppm . I n addition , tw o location s i n th e forme rSourc e Contro l Are a 2 exceede d th e Sourc e Contro l targe t PC B leve l o f 1 ppm . A s o f th e fal l 200 1 sampling , concentration s o f PCB s slightl yexceede d th e Rigg s Broo k trigge rleve l a t on e location . Biota wa s sample d i n 199 7 followin g completio n o f th e SCRA . Th e nex t biot a samplin g event , schedule d fo rfiv e year s later , wa s instea d complete d i n 200 0 a t th e reques t o f USEPA . Concentration s o f PCB s i n biot a wer e belo wth e threshol d leve l o f 2 pp m i n bot h samplin g events . Th e ROD/RSO W require d tha t CM P implemen t a publi c educatio n progra m t o increas e publi c awarenes s abou t th e statu s o f contaminatio n withi n Rigg s Brook . Th e statu s o f Rigg s Broo k wa s discusse d a s par

t o f th e CommunityMeeting s an d interactio n leadin g u p t o an d durin g SCRA . Du e t o minima l interes t expresse d b yth e publi c regardin g Rigg s Broo k o rth e Sit e sinc e th e completio n o f SCRA , furthe rmeeting s hav e no t bee n held . 4. 3 Syste m Operations/O& M A n O& M pla n fo rth e Sit e call s fo ra 10-yea rpost-closur e monitorin g perio d tha t wil l includ e inspections , routin e maintenance , an d repairs a s necessary . O& M activitie s fo rOU- 1 includ e inspection s an d wetlan d constructio n complianc e monitoring . Fo rOU-2 , O& M activitie s cove r checkin g th e integrit

yo f th e Sit e groundwate rmonitorin g wells . Sinc e OU- 3 consist s o f sedimen t an d biot a monitoring , ther e are n o O& M activities . Sit e inspection s fo rOU- 1 hav e bee n performe d b yCMP . CMP' s inspection s hav e reporte d that vegetatio n i s wel l developed , thicke ri n som e area s tha n others , an d that drainag e channel s are i n goo d conditio n an d functionin g a s designed . Annua l mowin g ha s no t bee n routinel y RI02942 F 4- 7 Tetra Tec h NUS , Inc .performed , a s planned , i n orde rt o allo wth e vegetatio n t o establis h itself . However , acces s t o

th e well s an d sit e acces s roa d ha s no t bee n a problem . Mino rerosio n o n th e easter n slop e o f th e Sit e wa s repaire d i n May1999 . Th e onl yerosio n note d sinc e wa s som e smal l ril l erosio n o n th e wester n ban k

of th e Lowe rLagoon ; th e are a wa s allowe d t o re-vegetat e naturally . Mino r rut s i n th e acces s roa d wer e repaire d i n Septembe r1999 . Complianc e monitorin g t o evaluat e wetlan d vegetatio n surviva l an d genera l wetlan d syste m recover yha s bee n complete d annuall yfo rthre e years followin g th e completio n of wetlan d restoratio n i n 1997 . Monitorin g wil l continu e i n year s 5 (2002 ) an d 1 0 (2007 ) t o asses s th e succes s o f th e wetlan d restoratio n an d achievemen t o f th e goal s establishe d i n th e desig n phase . Th e yea r3 (2000 ) restoratio n repor t (Smar t 2001 ) conclude d tha t th e Sit e ha d a post restoratio n wetlan d acreag e shortfal l o f approximatel y0. 2 acre s i n 2000 . Th e report' s assessmen t o f othe rgoal s o f th e project conclude d th e restoratio n has :

• maximize d th e percen t o f cove ran d th e diversit yo f th e plan t community , • establishe d effectiv e erosio n contro l an d stabilizatio n measures , • contribute d t o th e availabilityo f habitat i n th e surroundin g community , an d • reestablishe d wetlan d functio n an d values . O& M cost s fo rOU- 1 includ e sit e inspection s an d sit e repairs . O& M cost s wer e originall y estimate d a t approximatel y$15,00 0 fo ryea r1 an d $3,00 0 fo ryear s 2 throug h 10 . Accordin g t o th e R P contractor , cost s hav e bee n lowe rtha n originall yestimate d i n th e O& M pla n becaus e th e Sit e ha s no t bee n mowe d an d th e onl ysignifican t repai rwor k wa s mino rerosio n an d acces s roa d repai rconducte d i n 1999 . O& M costs , provide d b yth e R P contractor , are show n i n Tabl e 4-1 . Thes e cost s d o no t includ e th e semi-annua l sit e inspection s performe d b yCMP , CM P labo rcosts , o rth e wetlan d constructio n monitorin g performe d b yTh e Smar t Associates . Th e R P contracto rplan s t o revis e an d submi t th e O& M Plan . O& M cost s fo rOU- 2 have bee n limite d t o th e cost s of groundwate rmonitoring . N o maintenance ha s bee n require d t o dat e fo rth e wells . Accordin g t o th e R P contractor , groundwate rmonitorin g cost s are approximatel y$50,00 0 pe ryear . Since there i s n o O& M associate d wit h OU-3 , there are n o associate d O& M costs .

RI02942 F 4- 8 Tetra Tec h NUS , Inc .

### TABL E 4- 1 ANNUA L SYSTE M OPERATIONS/O& M COST S - OU- 1

FIVE-YEA R REVIE W REPOR T O'CONNO R COMPAN Y SIT E AUGUSTA , MAIN E Date s Fro m 11/97 11/9 8 11/9 9 

### 11/200 0 T o 11/98 11/9 9 

### 11/2000 11/200 1 Tota l Cos t $25 0 $150 0 $25 0 $25 0

RI02942 F 4- 9 Tetr a Tec h NUS , Inc .5. 0 PROGRES S SINC E LAS TFIVE-YEA R REVIE W



### Thi s i s th e firs t Five-Yea rrevie wfo rth e Site .

RI02942 F 5- 1 Tetr a Tec h NUS , Inc .6. 0 FIVE-YEA R REVIE W PROCES S

6. 1 Administrativ e Component s EPA , th e lea d agencyfo rthi s five-yea rreview , notifie d MEDE P an d th e RP s i n earl y200 2 that th e five-yea rrevie wwoul d b e completed . Th e RP s agree d t o assis t i n preparin g portion s o f th e require d information . CMP' s environmenta l consultant , Woodar d & Curran , Inc. , provide d USEP Awit h materia l fo rth e review . Thi s effort wa s conducte d betwee n Januar yan d Apri l 2002 . USEP Aissue d a scop e o f wor k t o TtNUS , W.A . No . 123-FRFE-0133 , unde rth e USEP A RAC 1 contract 68-W6-0045 , o n Marc h 1 , 200 2 t o assis t USEPAi n performin g th e five-yea r review . Th e USEP AWor k Assignmen t Manage rwa s Nanc ySmith ; suppor

t wa s provide d b y Terrenc e Connelly , th e USEP ARemedia l Project Manage rfo rth e O'Conno rSite . Wilke s Harpe ran d Han k

Andolse k

o f th e MEDE P wer e par t o f th e revie wteam . Th e Draft Five-Yea r Revie wRepor

t wa s provide d t o MEDE P fo rthei rrevie wi n earl yJuly . MEDE P transmitte d comment s t o EP Ai n a lette rdate d Augus t 9 , 200 2 (se e Appendi xF) . Th e origina l schedul e establishe d b yUSEP Aspecifie d completio n o f th e five-yea rrevie wb y Augus t 2002 . 6. 2 Community Notificatio n an d Involvemen t EP Aissue d a pres s releas e o n May8 , 200 2 that wa s publishe d i n th e Kennebe cJourna l announcin g EPA' s revie wo f th e progres s o f th e O'Conno rSit e cleanup . Th e pres s releas e encourage d publi cparticipation . There i s n o establishe d CommunityAdvisor yGroup . T o dat e EPA , MEDE P an d CM P hav e encountere d littl e participatio n o rinvolvemen t fro m th e loca l community . Al l site-relate d document s ar e availabl e at th e LithgowPubli cLibrar yi n Augusta . Accordin g t o staf f a t th e librar yther e ha s bee n limite d us e o f th e documents . 6. 3 Documen t Revie w Thi s five-yea rrevie wconsiste d o f a revie wo f relevan t document s includin g decisio n documents , wor k plans , an d variou s monitorin g report s (Se e Appendi xA) .

RI02942 F 6- 1 Tetra Tec h NUS , Inc .6. 4 Dat a Revie w

6.4. 1 Sourc e Contro l OU- 1 Sinc e th e completio n o f th e remedia l actio n fo rth e Sourc e Contro l Operabl e Uni t at th e Sit e i n 1997 , semi-annua l sit e inspection s hav e bee n conducte d b yCM P t o observ e an yphysica l change s at th e Site that woul d compromis e th e remedy . I n addition , wetland s constructio n monitorin g wa s conducte d annuall yfo ryear s 1 , 2 , an d 3 followin g wetland s restoratio n i n 1997 , an d wil l b e conducte d i n year s 5 an d 10 . Inspectio n report s conclud e tha t vegetatio n i s wel l developed , drainag e channel s ar e i n goo d conditio n an d functionin g a s designed . Th e mos t recen t wetlan d monitorin g repor t conclude s th e overal l Sit e i s providin g th e interspersio n o f wetlan d an d uplan d communitie s fo rth e recover yo f availabl e wildlif e habitat s (Smart , 2001) . Th e repor

t als o note d a n approximatel y0. 2 acre shortfal l i n th e post-restoratio n wetlan d area . 6.4. 2 Managemen t o f Migratio n OU- 2 Histori cresult s o f th e MO M monitoring , excludin g th e fiv e well s locate d i n th e TW AI I area , conducte d betwee n Octobe r1995 an d Septembe r200 1 an d prio ranalytica l results were reviewed . Targe t cleanu p level s hav e bee n se t fo rRGB s (0. 5 ug/L) , benzen e ( 5 ug/L) an d 1,4 - dichlorobenzen e (2 7 ug/L) . Ther e are n o establishe d cleanu p standard s fo rothe rVOC s i n th e 198 9 ROD . PCBs . Asid e fro m a fe winitia l samplin g event s (prio rt o 1994) , concentration s o f PCB s i n groundwate rsample s collecte d fro m well s outsid e o f th e TWAI I Are a hav e no t exceede d th e RO D targe t cleanu p leve l fo rPCB s (0. 5 ug/L) . Th e result s o f Marc h 199 9 groundwate ranalyse s usin g USEPAModifie d Metho d 68 0 fo rtota l homologu e PCB s showe d tota l PC S an d estimate d maximu m possibl e concentration s rangin g fro m 0.0 2 - 0.0 9 ug/L , wel l belo wth e RO D targe t cleanu p level . (W&C , 1999 ) VOCs . Concentration s o f volatil e organi ccompound s (VOCs ) hav e bee n fluctuatin g an d generall ydecreasing , an d are nea rtarge t cleanu p goal s i n well s outsid e th e TWAI I area . Th e downward tren d i n VO C concentration s i s mos t eviden t i n th e bedroc k wells . Th e concentration s i n th e overburde n well s are generall ylo wan d nea ro rbelo wth e targe t cleanu p levels . Th e benzen e targe t ( 5 ug/L) ha s no t bee n exceede d i n an yo f th e MO M wells , an d ha s generall y

RI02942 F 6- 2 TetraTechNUS , Inc .bee n foun d t o b e belo wo rclos e t o th e detectio n limit . Base d o n a revie wo f th e historica l

groundwate rmonitorin g data , th e concentration s o f 1,4 - dichlorobenzen e hav e fluctuate d an d hav e frequentl yexceede d th e targe t (2 7 ug/L) i n thre e o f th e MO M well s (MW-104B , OW-201B , an d MW-507A) . Thes e well s ar e al l locate d slightl ydowngradien t of th e TW AI I area . Thes e exceedance s ar e summarize d below . M W Numbe r MW-104 B OW-201 B MW-507 A Lowes t Cone . TDate ] <2. 5 pp b [3/26/97 ] < 0. 5 pp b [6/9/92 ] < 0. 5 pp b [3/29/00 ] Highest Cone . [Date ] 9 1 pp b [7/ 1 5/91 ] 5 6 pp b [12/9/97 ] 8 1 pp b [12/9/97 ] Lates t ConcJDate ] 3 0 pp b [9/ 1 8/01 ] 2 8 pp b [9/ 1 7/01 ] 3 6 pp b [9/ 1 8/01 ] Th e R P contracto rreporte d i n th e MO M Samplin g an d Analysi s Quarterl yReport , Septembe r 200 1 tha t a Man n Kendal l tren d tes t wa s performe d tha t indicate d a statisticall ysignifican t downwar d tren d i n th e 1,4-dichlorobenzen e concentration s i n thes e well s (W& C 2001) . Wel l MW-106 B flow s unde rartesia n condition s mos t o f th e year . A s such , i t provide s a n indicatio n o f th e wate rqualityo f th e bedroc k groundwate rmigratin g fro m th e Site . Lo wlevel s o f si xVO C compound s ar e regularl ydetecte d a t MW-106 B an d ar e reporte d t o b e generall y decreasin g o rstayin g at relativel yconstan t lo wlevels . Th e level s o f benzen e an d 1, 4 dichlorobenzen e are belo wtarge t limit s (W&C , 200 1 c) . Monitorin g well s MW-507Aan d MW-508 B wer e place d i n th e bedroc k trough , whic h i s th e primar ydischarg e pathwa yfo rgroundwate rfro m th e uppe rportion s o f th e Site . Th e concentration s o f 1, 4 dichlorobenzen e hav e generall ydecrease d belo wth e RO D limi t i n MW-507A , althoug h thi s limi t wa s exceede d i n th e sampl e obtaine d i n Septembe r200 1 durin g a perio d o f drought . Th e bedroc k concentration s o f thi s compoun d observe d i n MW-508 B are wel l belo wth e RO D limit . (W&C , 200 1 c) . Groundwate rmonitorin g usin g th e existin g 1 6 wel l monitorin g networ k shoul d continu e o n a semi-annua l basi s t o chec k fo rdecreasin g trend s i n 1,4-dichlorobenzen e concentrations . TW AI I Wells . Th e groundwate rfro m th e fiv e well s i n th e TW AI I Are a hav e typicall ynot bee n sample d becaus e th e oi l i n thes e well s woul d no t giv e representativ e result s o f th e dissolve d

RI02942 F 6- 3 Tetr a Tec h NUS , Inc .concentrations . Th e limite d numbe rfo rsample s collecte d fo rVO C an d PC B analysi s wer e

determine d t o no t b e representativ e o f actua l dissolve d contaminant s i n th e groundwater . T o dat e th e MO M monitorin g progra m (well s outsid e TWAII ) ha s show n tha t groundwate r meet s th e targe t cleanu p goal s a t th e perimete ro f th e Site , an d a t othe rlocation s show s decreasin g trend s fo rthos e compound s no t ye t a t th e targe t cleanu p goal . Withi n th e TWAI I area , concentration s o f RGBs , benzene , an d 1,4-dichlorobenzen e excee d th e targe t cleanu p goals . Th e sourc e o f thi s contaminatio n i n groundwate ri n th e TW AI I are a i s believe d t o b e th e residua l oi l trappe d i n th e cracks i n th e clayan d bedroc k fractures . Th e TW

AI I are a well s ar

e th e subjec t o f a n applicatio n fo ra T l waive rbein g sough t b yCMP . Future monitorin g i n th e TWAI I well s an d surroundin g are a ma ychang e base d o n actio n take n o n th e T l waive rrequest . 

### 6.4. 3 Rigg s Broo k OU- 3 Sedimen t monitorin g ha s bee n conducte d annuall yat Rigg s Broo k sinc e 1996 , an d biot a monitorin g wa s conducte d i n 199 7 an d 2000 . Th e si xyear s o f sedimen t samplin g ar e summarize d below . PC B concentration s hav e exceede d th e 5 pp m trigge rleve l i n a fe w locations . PC B concentration s i n biot a hav e no t exceede d th e 2 pp m threshol d level . Yea r Result s 

### 199 6 Concentration s o f tota l PCB s wer e belo wth e 5 pp m trigge rleve l a t al l sedimen t

sampl e locations . 

### 199 7 PC B concentration s exceede d 5 pp m a t tw o sedimen t sampl e location s (800 4

an d 8013) . Mor e rigorou s samplin g wa s conducte d an d th e sedimen t wa s remediate d b yexcavatin g th e tw o smal l ho t spots . 

### 199 8 PC B concentration s exceede d 5 pp m a t tw o samplin g location s (800 6 an d 3018) . 

### 199 9 PC B concentration s a t sampl e locatio n 800 6 continue d t o excee d 5 pp m bu t wer e

lowe rtha n 199 8 concentrations . Th e PC B concentratio n at sampl e locatio n 301 8 wa s belo wth e trigge rleve l i n 1999 . 200 0 PC B concentration s a t sampl e locatio n 800 6 continue d t o excee d 5 pp m bu t

decrease d fro m 199 9 concentrations . PCB s a t sampl e locatio n 301 8 staye d belo wth e trigge rlevel . USEP Arequeste d tha t additiona l sedimen t sample s b e collecte d i n th e are a betwee n th e forme rSourc e Contro l are a (OU-1 ) an d Rigg s Brook . O f thes e additiona l samples , concentration s o f PCB s exceede d th e trigge r leve l o f 5 pp m a t fou rou t o f 5 1 locations . 200 1 PC B concentration s a t sampl e locatio n 800 6 droppe d belo wth e 1 pp m cleanu p

level . PCB s a t sampl e locatio n 301 8 wer e slightl yabov e th e trigge rleve l (6.1 J ppm) . Th e fou radditiona l location s wher e exceedance s wer e observe d i n 200 0 wer e sample d agai n i n 2001 , an d th e concentration s wer e belo w5 pp m a t al l fou r locations . Source : W& C 200 1 e

RI02942 F 6- 4 TetraTechNUS , Inc .Th e supplementa l samplin g gri d establishe d byUSEPAi n 200 0 showe d th e fou rexceedance s

o f th e Rigg s Broo k

5 pp m PC B trigge rleve l mentione d i n th e tabl e above , a s wel l a s tw o exceedance s o f th e Sourc e Are a 1 pp m PC B targe t level . Th e PC B concentration s wer e 1. 4 an d 3. 8 pp m a t th e tw o Sourc e Are a 1 location s o n th e slop e downgradien t o f th e lowe rlagoo n (W&C , 200 1 b) . Accordin g t o th e R P contractor , thes e tw o location s hav e no t bee n re-sample d sinc e 2000 . 6. 5 Sit e Inspectio n Asit e inspectio n wa s conducte d o n Ma y22 , 200 2 wit h representative s fro m EPA , MEDEP , CMP , EPA' s contracto ran d CMP' s contractor . Th e inspectio n include d a sit e walkove rfocusin g o n th e Designate d Are a boundar yan d observation s o f th e vegetate d cover , monitorin g wells , restore d wetlan d areas , th e uplan d mars h an d Rigg s Broo k area . Th e Sit e i s n o longe rsecure d wit h fencin g an d no t al l o f th e monitorin g well s hav e secur e locks . I n 1997 , th e fenc e wa s determine d t o b e n o longe rnecessar yonc e th e soi l cove rwa s place d ove rth e Designate d Area , eliminatin g thi s exposur e route . Ther e ha s bee n n o reporte d vandalis m o rtrespassin g o n th e Site . Th e vegetatio n i s wel l established , swale s constructe d t o direc t runof f fro m th e lagoon s towar d Rigg s Broo k are i n goo d repair . Th e Sit e inspectio n report , includin g sit e photos , i s include d i n Appendi xB . CM P staf f chec k

th e Sit e frequentl yan d state d tha t whil e th e Sit e i s no t routinel ymowed , mowin g wil l b e performe d i f require d fo racces s t o well s an d fo rongoin g operations . Sinc e th e Sit e wa s farmlan d i n th e 1950' s th e perimete rtree s an d othe rvegetatio n hav e becom e well establishe d i n area s where there were n o activ e operations . Man ybird s were hear d an d see n durin g th e walkover . N o significan t developmen t o f surroundin g area s i s underway ; municipa l wate rsuppl yi s available . As note d i n Sectio n 3.2 , zonin g district s encompassin g th e Sit e permi t residentia l development . Institutiona l control s ar e covere d i n th e Declaratio n o f Restrictiv e Covenan t signe d byMEDE P an d CM P an d hel d i n escrowbyMEDEP . CM P an d th e R P contracto r reporte d tha t ther e hav e bee n n o know n violation s o f th e term s o f th e Covenant .

RI02942 F 6- 5 Tetr a Tec h NUS , Inc .6. 6 Interview s

Genera l discussion s an d observation s wer e documente d durin g th e sit e inspectio n o n Ma y22 , 2002 . Telephon e interview s wer e conducte d wit h othe rindividuals . Al l individual s contacte d regardin g th e five-yea rrevie ware show n i n Appendi xC . Ro yKoster , CMP , note d tha t CM P personne l visi t th e Sit e o n a monthl ybasi s an d chec k th e well s i n th e TW

A I I are a fo rfloatin g oil . Whe n present , oi l i s collecte d usin g absorben t pad s whic h ar e the n take n t o a CM P transfe rfacilit yi n Augusta . CM P ha s n o plan s t o develo p th e site ; i t wa s note d tha t mos t o f th e developmen t i n August a i s o n th e wes t sid e o f th e Kennebe c River . Mr . Bil l Bridgeo , August a Cit yManager , was contacte d bytelephon e o n Jun e 3 , 2002 . H e kne w o f th e Sit e an d it s locatio n bu t state d tha t n o concern s abou t th e Sit e hav e bee n brough t t o hi s attentio n ove rth e pas t fe wyears . Mr . Horac e Rodrigu e wa s contacte d b ytelephon e o n Jun e 3 , 2002 . H e state d tha t th e partie s responsibl e fo rth e cleanu p of th e Sit e di d a "super b job. " Mr . Rodrigu e ha s observe d all-terrai n vehicle s usin g th e Site . H e own s propert ydirectl yacros s Rout e 1 7 fro m th e Sit e an d attribute s hi s inabilityt o sel l i t ove rth e pas t 1 0 year s t o th e propert ybein g acros s th e stree t fro m a "dump " site . Curren t lan d us e an d floo d zon e map s wer e obtaine d fro m th e August a Cit yService s office . Staf f a t th e offic e wer e familia rwit h th e locatio n o f th e O'Conno rSit e bu t di d no t expres s an y concern s abou t th e activitie s that hav e bee n completed . Th e administrativ e recor d an d sit e document s are availabl e at th e Lithgo wPubli cLibrar yi n Augusta . Librar

ystaf f indicate d that fe windividual s hav e accesse d th e documents . T o dat e USEP Aha s receive d n o respons e fro m th e publi cfollowin g publicatio n o f th e pres s releas e i n May2002 .

RI02942 F 6- 6 Tetra Tec h NUS , Inc .7. 0 TECHNICA L ASSESSMEN T

Th e followin g section s evaluat e th e remed ybase d o n it s functio n i n accordanc e wit h decisio n documents , it s adherenc e t o vali d ris k dat a an d scenario s an d an yothe rinformatio n that coul d hav e affecte d th e remedy' s protectiveness . ARAR s an d T o B e Considere d (TBC ) guidance fo r th e Sit e identifie d durin g th e developmen t o f th e 198 9 RO D alon g wit h curren t ARAR s an d TBC s ar e provide d i n Appendi xD o f thi s Repor t fo rreference . 7. 1 Questio n A : I s th e Remed y Functionin g a s Intende d b y th e Decisio n

Documents ? 7.1. 1 OU-1 : Sourc e Contro l Remedia l Actio n Remedia l actio n performanc e an d monitorin g results . Th e informatio n presente d i n th e Fina l Sourc e Contro l Remedia l Actio n Repor t (W&C , 1998 ) show s tha t th e Sit e wa s remediate d i n accordanc e wit h th e requirement s o f th e RO D (USEPA , 1989 ) a s modifie d b yth e ES D (USEPA , 1994) . Th e soi l excavatio n an d coverin g o f th e Designate d Are a wit h clea n fil l durin g th e SCR A reduce d publi chealt h an d environmenta l risk s fro m direc t contact wit h contaminate d soil s an d sediments , exposur e t o surfac e water , an d reduce d publi chealt h ris k fro m inhalatio n o f contaminate d vapors . Th e sit e inspection s sho wthat th e integrit yo f th e soi l cove rplace d ove r th e Designate d Are a ha s bee n maintaine d an d th e Sourc e Contro l remed yi s functionin g a s intended . EPA , MEDEP , an d CM P are finalizin g a n O& M pla n t o ensur e th e long-ter m integrit y o f th e soi l cove rove rth e Designate d Area . Thi s pla n wil l includ e th e collectio n o f shallo w subsurfac e sample s coinciden t wit h futur e five-yea rreview s t o asses s whethe rthere ar e PCB s abov e th e 1 pp m concentratio n i n th e soi l cover . Wetland s Constructio n Monitorin g Report s complete d b ySmar t Associate s i n 1998 , 2000 , an d 200 1 conclud e tha t th e Sit e i s achievin g project goals . Operation s an d Maintenanc e Costs . Maintenanc e o f th e Site , includin g th e grave l acces s road , soi l cove ro n th e Designate d Area , an d th e restore d wetland s ha s bee n effective . A s discusse d earlie ri n thi s report , mino rerosio n ha d occurre d o n th e soi l cove ran d th e grave l road , an d wa s repaired . Th e mino rerosio n that di d occu rwa s no t deep , an d di d no t affec t th e protectivenes s o f th e remedy .

RI02942 F 7- 1 Tetra Tec h NUS , Inc .O& M cost s ar e les s tha n originall yestimate d becaus e sit e repairs hav e bee n minima l (se e

Tabl e 4-1) . Th e O& M cost s presente d i n Tabl e 4- 1 d o no t includ e th e sit e inspection s whic h are performe d b yCM P o rth e wetlan d monitorin g performe d b ySmar t Associates . Opportunitie s fo rOptimization . Thre e measure s fo roptimizin g maintenanc e o f th e SCR Aar e suggested . First , i t i s propose d tha t on-sit e markers b e installe d t o mor e clearl ydefin e th e Designate d Area . Thi s woul d enabl e personne l conductin g sit e inspection s t o se e th e boundarie s o f th e Designate d Are a whil e walkin g aroun d th e Site . Secondly , revisio n an d agencyapprova l o f th e O& M Pla n t o reflect curren t O& M practice s i s suggested . Thi s pla n wil l includ e th e collectio n o f shallo wsubsurfac e sample s coinciden t wit h futur e five-yea rreview s t o asses s whethe rther e ar e PCB s abov e th e 1 pp m concentratio n i n th e soi l cover . Th e thir d optimizatio n suggestio n i s to reevaluat e Site institutiona l control s currentl ycovere d by th e Declaratio n o f Restrictiv e Covenan t betwee n th e MEDE P an d CMP . Al l parties , e.g . USEPA , MEDE P an d CMP , shoul d agre e wit h th e for m an d duratio n o f institutiona l control s fo r th e Site . Indicators o f Remed yProblems . Base d o n sit e inspection s conducted , ther e d o no t appea rt o b e an yindicator

s o f remed yproblems . Implementatio n o f Institutiona l Controls . Th e Declaratio n o f Restrictiv e Covenan t prohibit s an y activitythat migh t disrup t remedia l o rmonitorin g measure s at th e Site , o ran yus e o f th e groundwate rbeneat h th e propertywithou t prio rwritte n approva l o f th e MEDEP . Th e Declaratio n o f Restrictiv e Covenan t als o require s tha t CM P maintai n th e propertyt o ensur e th e ongoin g adequac

yo f th e remediatio n implemente d unde rth e Consen t Decree . Th e implementatio n o f institutiona l controls , eve n thoug h th e restrictiv e covenan t i s i n escro wan d i s therefor e no t legall yenforceable , ha s thu s fa reffectivel yensure d th e integrit yo f th e remedia l measure s conducte d at th e Site , an d ha s prevente d exposur e t o Sit e soils . Th e Agreement , Releas e an d Stipulatio n an d th e Declaratio n of Restrictiv e Covenan t are provide d i n Appendi xE . Th e R P contracto rha s reporte d tha t n o activitie s hav e bee n observe d o n th e Sit e tha t woul d hav e violate d th e institutiona l controls .

RI02942 F 7- 2 TetraTechNUS , Inc .7.1. 2 OU-2 : Managemen t o f Migratio n

Remedia l Actio n Performanc e an d Monitorin g Results . Revie wo f relevan t MO M document s an d result s o f th e quarterl yan d semi-annua l groundwate rmonitorin g indicate s that th e MO M remed yi s functionin g a s intende d excep t withi n th e TWAI I Area . A s describe d earlie ri n thi s report , concentration s o f PCB s an d VOC s eithe rmee t RO D targe t cleanu p goal s o rar e trendin g downward , excep t i n a n uplan d are a includin g an d surroundin g th e TW AI I Area . Althoug h th e SCR Awa s successfull ycompleted , smal l amount s o f residua l oil , containin g PCB s an d VOCs , remai n i n fracture s i n th e cla yan d t o a limite d exten t i n bedrock . Howeve rlittl e movemen t o f residua l oi l ha s bee n observed . Groundwate rremediatio n wit h th e VE R syste m an d monthl ypassiv e oi l recover yha s remove d approximatel y8 5 gallon s o f residua l oi l fro m th e TWAI I well s sinc e 1992 , an d abou t 2 7 gallon s o f that sinc e th e completio n o f th e SCR Ai n 1997 . Groundwate rmonitorin g result s indicat e decreasin g trend s i n concentration s o f VOC s ove rth e entire Site , includin g th e TW AI I Area . Du e t o th e fac t that th e remed yi s no t functionin g a s intende d withi n th e TWAI I Area , a T l Evaluatio n Repor

t supportin g a T l waive rfo rth e TWAI I are a ha s bee n submitte d t o USEP Afo r approval . Thi s T l Repor t propose s a groundwate rremed ythat woul d b e protectiv e o f huma n healt h an d th e environmen t an d include s a reques t fo ra T l waive rfro m specifi cARAR s withi n a n are a establishe d a s th e T l Zone . Th e propose d T l Zon e encompasse s th e TWAI I Are a an d th e are a associate d wit h shallo wgroundwate rflo wt o th e sout h o f th e TWAI I Area . Monitorin g well s alon g th e boundar yo f th e propose d T l Zon e wil l b e monitore d t o ensure that drinkin g wate rstandard s ar e me t outsid e o f th e propose d T l Zone . Operation s an d Maintenance/Costs . Ther e hav e bee n n o O& M cost s fo rth e MO M othe rtha n th e wate rqualit

ymonitoring . N o maintenanc e ha s bee n require d fo rth e wells . Base d o n informatio n provide d b yth e R P contractor , groundwate rmonitorin g cost s ar e approximatel y $50,00 0 pe ryear . Opportunitie s fo rOptimization . Th e groundwater-monitorin g networ k shoul d b e reevaluate d an d th e location s an d numbe ro f well s include d i n th e networ k modifie d base d o n agreemen t b y USEPA , MEDE P an d CMP . I t ma yb e possibl e t o reduc e th e numbe rof well s routinel ysample d base d o n a revie wo f historica l groundwate rresults . RI02942 F 7- 3 TetraTechNUS , Inc .Th e VE R Phas e II I activitie s conducte d i n 200 1 extracte d approximatel y19. 8 gallon s o f oi l fro m

th e TW AI I wells , an d primaril yfro m th e bedroc k wells . Thi s wa s th e firs t tim e a vacuu m ha d bee n applie d directl yt o thes e wells . T o determin e i f furthe ramounts o f oi l ca n b e extracte d fro m thes e wells , th e VE R shoul d continu e t o b e applie d t o th e TWAI I well s annuall ydurin g a perio d of lowgroundwate r(probabl ylate rsummer ) an d th e recover

yrat e of oi l tracked . A s previousl ystated , groundwate rsample s collecte d fro m observatio n well s i n th e TWAI I Are a ar e not representative of th e actua l dissolve d contaminants i n th e groundwater . Thi s i s du e t o a n oi l emulsio n tha t i s ofte n observe d i n thes e wells . Therefore , i t i s propose d that thes e well s continu e t o b e observe d fo roil , bu t that the yno t b e adde d t o th e MO M progra m at thi s time . Indicators o f Remed yProblems . A s state d above , th e indicato rthat th e remed yi s no t functionin g a s intende d i n th e TW AI I Are a i s th e residua l oi l observe d i n cracks i n th e cla ytha t continue s t o b e a sourc e of PCB s an d VOC s i n groundwate rat concentration s that excee d thei r respectiv e cleanu p levels . Groundwate ri n th e TW AI I are a i s th e subject o f a n applicatio n fo ra T l waive rbein g sough t b yCMP . Th e applicatio n fo ra T l waive ri s include d i n a T l Evaluatio n Repor t tha t ha s bee n submitte d t o USEP Afo rapproval . Implementatio n o f Institutiona l Controls . Th e implementatio n o f institutiona l controls , throug h th e Declaratio n of Restrictive Covenant , ha s thu s fa rprevente d exposure t o contaminate d groundwate ra t th e Site . Areevaluatio n o f th e for m an d duratio n o f institutiona l control s b y USEPA , MEDE P an d CM P i s suggeste d t o ensure th e integrit yo f th e remedia l measure s conducte d a

t th e Site . 7.1. 3 OU-3 : Rigg s Broo k Remedia l Actio n Performanc e an d Monitorin g Results . Revie wo f document s relate d to , an d samplin g dat a obtaine d from , Rigg s Broo k sedimen t an d biota , indicate s tha t subsequen t t o PC B hot spot remova l i n 1997 th e remed yi s functionin g a s intende d byth e RO D an d RSOW . Sedimen t samplin g an d analysi s ha s bee n conducte d annuall ysinc e 1996 , an d biot a samplin g an d analysi s wa s conducte d i n 199 7 an d 2000 . Ove rth e las t si xyears PC B concentration s i n sedimen t hav e exceede d th e RO D cleanu p goa l o f 1 pp m an d sporadicall yexceede d th e RO D 5 pp m trigge rleve l i n severa l locations . Th e

RI02942 F 7-4 Tetr a Tec h NUS , Inc.Mann-Kendal l statistica l tren d analysi s doe s no t sho wan ystatisticall ysignifican t trends . I n

200 1 ther e wa s on e sedimen t sampl e locatio n wher e PCB s exceede d 5 pp m (6. 1 ppm) , an d on e othe rlocatio n that exceede d 1 ppm . Al l th e remainin g sedimen t sample s containe d les s tha n 1 pp m o f PCBs . Continue d monitorin g ha s show n tha t ove rtim e th e PC B concentration s hav e continue d t o decrease , an d i n mos t case s th e concentration s hav e decrease d unti l the y ar e belo wth e cleanu p goal . Th e result s o f th e 199 7 an d 200 0 biot a samplin g event s hav e show n tha t PC B concentration s hav e no t exceede d 2 pp m (th e RO D threshol d limit) . Accordin g t o th e 200 0 Sedimen t an d Biot a Monitorin g Report , th e smal l amoun t of PCB s detecte d i n Rigg s Broo k sedimen t doe s not appea rt o b e impactin g biot a sinc e th e PC B concentration s i n biot a fro m th e 199 7 an d 200 0 samplin g event s hav e remaine d consisten t o rslightl ydecrease d (W& C 200 1 b) . Althoug h no t foun d t o b e statisticall ysignificant , decreasin g concentration s o f PCB s hav e bee n foun d a t mos t o f th e sedimen t samplin g locations . Additionally , sinc e th e exceedance s o f th e sedimen t trigge r leve l d o no t appea rt o b e impactin g th e biota , th e remed yi s functionin g a s intended . Operation s an d Maintenanc e Costs . Sinc e th e remedia l actio n fo rOU- 3 i s monitoring , ther e ar e n o othe roperation s o rmaintenanc e occurrin g a t Rigg s Brook . Th e cost s o f th e ho t spo t remediatio n tha t wa s conducte d i n 199 7 wer e include d wit h th e Sourc e Contro l activitie s an d hav e no t bee n separatel ytracked . Base d o n informatio n fro m th e R P contractor , annua l cost s fo rRigg s Broo k

sedimen t samplin g an d analysi s ar e approximatel y$20,000 . Opportunitie s fo rOptimization . Th e possibilit yo f decreasin g th e samplin g location s ha s bee n discussed . However , give n th e transien t nature o f sediments , USEP Aha s decide d t o continu e wit h th e sam e monitorin g progra m fo rth e duratio n o f th e ROD-specifie d perio d (unti l 2006) . Indicator s o f Remed yProblems . Base d o n annua l sedimen t an d biot a monitoring , there d o no t appea rt o b e an yindicators o f remed yproblems . Althoug h PCB s hav e bee n detecte d eac h yea r i n on e o rmore sedimen t samples , th e concentration s are onl yslightl yexceedin g th e trigge r leve l o f 5 pp m a t a fe wlocation s an d overal l concentration s o f PCB s appea rt o b e decreasing . I n addition , concentration s o f PCB s i n sedimen t d o no t appea rt o b e impactin g biot a (al l sample s les s tha n th e threshol d leve l o f 2 ppm) .

RI02942 F 7- 5 Tetra Tec h NUS , Inc .Implementatio n o f Institutiona l Controls . Institutiona l control s fo rth e Site , describe d i n OU-1 ,

als o appl yt o OU-3 . 7. 2 Questio n B : Ar e Th e Exposur e Assumptions . Toxicit vData . Cleanu p

Level s an d Remedia l Actio n Objective s (RAOs ) Use d a t th e Tim e o f Remed ySelectio n Stil l Valid ? 7.2. 1 OU-1 : Sourc e Contro l Remedia l Actio n Change s i n Standard s an d TBCs . A s a par t o f thi s five-yea rreview , th e ARAR s presente d i n th e RO D hav e bee n reviewed , an d a revie wo f curren t ARAR s ha s bee n conducted . Du e t o th e fac t tha t SCR Aha s bee n completed , mos t ARAR s fo rsoi l contaminatio n cite d i n th e RO D hav e bee n met . Ther e ar e n o curren t chemical-specifi cARAR s that appl yt o soi l contaminant s a t th e Site . TB C guidanc e tha t wa s writte n followin g th e 198 9 RO D include s th e 199 0 USEP AGuidance on Remedial

Actions fo r Superfund

Sites with PCB Contamination, th e 199 4 USEP ARevised Interim Soil Lead Guidance

fo r CERCLASites

an d RCRACorrective

Action Facilities, an d th e 199 7 MEDE P Remedial Action Guidelines

(RAGs) . Th e USEP AGuidance o n Remedial

Actions fo r Superfund

Sites with PC B Contamination

recommend s soi l actio n level s o f 1 pp m fo rsite s i n residentia l area s an d 10-2 5 pp m fo rsite s i n industria l areas . Th e USEP ARevised Interim Soil Lead Guidance

recommend s 40 0 pp m fo rlea d i n soils . Th e MEDE P RAG s fo rPCB s rang e fro m 2. 2 t o 8. 1 pp m fo rresidential , trespasse ran d adul t worke rguidelines . Benzo(a)pyren e i s use d a s a n indicato rcontaminan t fo rcPAHs , an d th e RAG s rang e fro m 2 t o 9 ppm . Fo rlead , th e RAG s rang e fro m 37 5 t o 70 0 ppm . Thes e mor e recen t guidanc e are les s conservativ e tha n th e RO D targe t cleanu p goal s o f 1 pp m PCBs , 1 pp m cPAH s an d 24 8 pp m lea d use d t o remediat e th e area s o f th e Sit e outsid e th e Designate d Area . Althoug h th e targe t cleanu p goal s insid e th e Designate d Are a wer e 1 0 pp m PCBs , 1 0 pp m cPAH s an d 24 8 pp m lead , th e to p 1 2 inche s o f soi l o n th e Designate d Are a ha s concentration s o f PCB s les s tha n 1 ppm . Therefore , additiona l guidanc e writte n afte rth e 198 9 RO D doe s no t affec t th e protectivenes s o f th e SCR Acomplete d a t OU-1 . Change s i n Exposure Pathways . Seve n exposur e scenario s wer e identifie d i n th e Endangermen t Assessmen t (Clement , 1988) , includin g thre e potentia l curren t exposure s an d

RI02942 F 7- 6 Tetra Tec h NUS , Inc .fou rpotentia l futur e exposures . Thes e exposure s includ e contac t bytrespassers , recreationa l fishing , an d potentia l futur e residentia l exposures . Lan d us e at th e Sit e ha s no t change d an d i s no t expecte d t o change , an d there are n o additiona l route s o f exposure . Change s i n Toxicit yan d Othe rContaminan t Characteristics . Althoug h toxicit yfactor s hav e change d fo rsom e o f th e chemicals , th e cance rslop e factor s (CSFs ) (formerl ycalle d cance r potencyfactors ) have , i n general , decreased . Adecreas e i n a cance rslop e facto rindicate s that potentia l ris k

fro m exposur e t o contaminant s i s lowe rtha n previousl ycalculated . Th e contaminant s wit h th e greates t cance rris k potentia l at th e Sit e were PCB s an d cPAHs . CSF s fo rPCB s hav e bee n change d fro m 7. 0 (mg/kg/day)" 1 t o 7. 7 (mg/kg/day)" 1

. Considerin g th e concentration s o f PCB s that are bein g detecte d o n site , i t i s unlikel ytha t thi s smal l chang e coul d adversel yaffec t th e protectivenes s o f th e remedy . I n addition , ris k value s fo rcPAHs , a s evaluate d b yusin g benzo(a)pyrene , hav e bee n decreased , wit h th e curren t ora l CS F o f 7. 3 (mg/kg/day)" 1 lowe rtha n th e 198 8 valu e o f 11. 5 (mg/kg/day)" 1

. Therefore , th e change s i n toxicity o f thes e compound s woul d no t affec t th e outcom e o f th e Endangermen t Assessmen t becaus e ther e i s n o notabl e chang e i n th e ris k o f cance rat th e Site . Ther e hav e als o bee n change s mad e t o th e Ris k Referenc e Dose s (RfDs ) since th e Endangermen t Assessment . Thes e value s ar e use d t o quantif yth e ris k

associate d wit h specifi c contaminants . Th e alteration s mad e t o th e RfD s use d t o determin e ris k fo rthi s Sit e woul d no t affec t th e protectivenes s o f th e remedy . O f th e seve n contaminant s fo rwhic h RfD s wer e liste d i n 1988 , thre e hav e no t changed , tw o hav e increase d slightl yan d on e decrease d b ya n orde ro f magnitude . Non e o f thes e wer e contaminant s o f concer n i n th e ROD . Ris k associate d wit h non carcinogeni cPAH s wa s no t calculate d i n th e assessment . RfD s are no wavailabl e fo rman yo f thos e compounds . Base d o n th e lo wcleanu p level s fo rth e cPAH s an d PCB s (whic h woul d potentiall yb e co-locate d wit h th e non-carcinogeni cPAHs) , cleanu p o f th e non-carcinogeni c PAH s i s expecte d t o hav e occurre d durin g remediation . Change s i n Ris k

Assessmen t Methods . Th e onl ychange s i n ris k assessmen t method s sinc e th e RI/F S are th e manne ri n whic h lea d i s evaluated , th e wayi n whic h ris k t o constituent s i n ai r i s estimated , an d th e us e o f certai n exposur e estimates . Non e o f thes e change s affec t th e protectivenes s o f th e remedy .

RI02942 F 7- 7 TetraTechNUS , Inc .Currently , lea d exposure s to childre n ar e modele d usin g th e Integrate d Exposur e Uptak e Biokineti cMode l (IEUBK) , availabl e fro m USEPA . Federa l standard s fo rlea d ar e currentl yse t a t 40 0 mg/k g fo rresidentia l use , base d o n thi s model . Becaus e th e cleanu p leve l establishe d fo rlea d i n soi l wa s 24 8 mg/kg , th e cleanu p goa l i s protectiv e o f potentia l futur e us e o f th e Site . Th e method s use d t o asses s ris k t o constituents i n ai rhav e changed . I n addition , som e of th e defaul t exposur e assumption s hav e changed , specificall yfo rderma l exposure , base d o n studie s reviewe d b yUSEPA . Whil e thes e change s woul d hav e sligh t effect s o n calculate d risks , there i s n o potentia l fo rexposur e a s lon g a s th e soi l cove rove rth e Designate d Are a i s maintaine d an d therefor e th e soil s wit h les s tha n 1 0 pp m PCB s are no t accessible . Th e targe t cleanu p goal s se t i n th e RO D remai n protectiv e o f th e exposure s an d receptors identifie d fo rth e Site . Expecte d Progres s Toward s Meetin g RAOs . Th e SCR Awa s complete d an d met th e remedia l actio n goal s fo rOU-1 . 7.2. 2 OU-2 : Managemen t o f Migratio n Change s i n Standard s an d TBCs . Th e primar ychang e t o th e ARAR s list fo rgroundwate ri s th e additio n o f th e 199 2 Main e Maximu m Exposure Guideline s (MEGs) . Th e effec t o f thi s ARA R i s th e additio n o f fiv e VOC s t o th e list o f compound s i n Sit e groundwate rtha t have promulgate d cleanu p standards . There ar e als o MCL s fo rthre e o f thes e VOCs ; however , thei rvalue s ar e th e sam e o rhighe rtha n thei rrespectiv e MEGs . I n addition , th e 199 2 ME G of 0.0 5 pp b PCB s i s significantl ylowe rtha n th e 198 9 RO D targe t cleanu p goa l o f 0. 5 pp b fo rPCBs . Thes e MEG s wer e revise d i n 2000 , an d th e ME G fo rPCB s wa s onc e agai n change d t o 0. 5 ppb , bu t thes e revision s have not bee n promulgated . Accordin g to th e MEDEP , th e 1992 MEG s ar e reference d i n th e Main e hazardou s wast e regulations , are enforceabl e an d are therefor e applicabl e t o thi s Site . Therefore , fo rth e purpos e o f thi s five-yea rreview , th e 1992 ME G fo rPCB s o f 0.0 5 pp b i s th e applicabl e ARA R fo rgroundwater . Whe n th e groundwate rcleanu p targe t goa l fo rthi s Sit e wa s se t at 0. 5 ppb , th e curren t MCLs an d Main e MEG s wer e take n into consideration . Sinc e thes e MEG s have becom e mor e stric t since th e RO D wa s issued , i t ma yb e necessar

yi n th e future t o recalculat e ris k base d o n thes e ne wstandard s t o ensure th e protectivenes s o f th e remedy .

RI02942 F 7- 8 Tetr a Tec h NUS , Inc .Change s i n Exposure Pathways . Althoug h institutiona l control s are i n plac e at th e Site , an d

there are n o plan s t o develo p th e Sit e fo rresidentia l o rcommercia l use , future residentia l us e i s protectiv e o f othe rreceptors , includin g potentia l commercia l workers an d temporar y constructio n workers . On e pathwayexclude d fro m th e Endangermen t Assessmen t wa s exposur e t o volatile s i n indoo rai roriginatin g fro m shallo wgroundwater . Arevie wo f curren t groundwate rdat a wa s conducte d t o determin e whethe rthi s rout e o f exposur e i s complete . I n th e area s o f th e Sit e tha t coul d b e redevelope d (i.e. , o n more eve n terrain) , shallo wgroundwate r i s primaril ya t a dept h o f 1 0 t o 2 0 fee t belo wgroun d surface . Concentration s o f tw o VOCs , 1,2 - dichlorobenzen e (rangin g fro m 9 t o 9 3 ug/L ) an d 1,4-dichlorobenzen e (rangin g fro m 4 t o 3 6 ug/L) , hav e onl yslightl yexceede d th e RO D targe t cleanu p goa l an d MEG s (2 7 ug/ L an d 8 5 ug/L , respectively) , at on e wel l (507A ) i n th e shallo waquife rdurin g th e 200 1 sampling . Thes e concentration s are no t expecte d t o adversel yimpact indoo rai ri n potentia l futur e buildings . Bedroc k groundwate rwa s no t evaluate d fo rthi s pathway , a s shallo wgroundwate ri s th e potentia l sourc e fo rvolatilizatio n int o indoo rair . Base d o n th e limite d concentration s i n shallo w groundwater , th e exposur e pathway s tha t wer e evaluate d remai n valid . Change s i n Toxicitvan d Othe rContaminan t Characteristics . A s discusse d fo rOU-1 , althoug h toxicityfactor s fo rsom e chemical s hav e changed , i n general , th e CSF s hav e decreased . Th e ora l CS F fo r1,4-dichlorobenzene , PCB s an d benzen e ar e 2. 4 E- 2 (mg/kg/d)" 1 , 7. 7 (mg/kg/d)" 1 an d 2.9 0 E- 2 (mg/kg/d)" 1 , respectively . Th e ora l Rf D (fo rnon-cance routcomes ) fo rPCB s i s 2.00E- 5 (mg/kg/d)" 1

. Th e Rf D fo rbenzen e an d 1,4-dichlorobenzen e wer e no t assesse d unde r th e EPA' s Integrate d Ris k Informatio n Syste m (IRIS) . Th e inhalatio n toxicityfacto rfo r 1,4-dichlorobenzen e i s 8. 0 E- 1 mg/m 3

. Thi s valu e wa s not i n th e origina l assessment , no rwa s i t publishe d fo rbenzen e o rPCB s i n IRIS . Fo ral l thre e o f thes e contaminants , th e CSF s reference d i n th e Endangermen t Assessmen t hav e sinc e bee n changed , howeve ronl yPCB s no whav e a highe rCSF . Onl yon e o f th e abov e contaminant s ha s bee n detecte d i n groundwate r outsid e th e Designate d Area , an d th e targe t cleanu p goa l fo r1,4-dichlorobenzen e i s lowe rtha n th e MEG . Additionally , th e concentration s i n th e shallo wgroundwate rare belo wo rveryclos e t o th e MEG . Revie wo f thi s informatio n indicate s tha t th e remed yremain s protective . Change s i n Ris k

Assessmen t Methods . Sinc e th e targe t cleanu p level s fo rgroundwate rwer e base d o n MCLs an d MEGs , change s i n ris k assessmen t method s woul d b e accounte d fo r becaus e MCL s an d MEG s us e conservativ e defaul t assumption s an d are update d periodically .

RI02942 F 7- 9 Tetra Tec h NUS , In cExpecte d Progres s Toward s Meetin g RAOs . AT l waive rha s bee n requeste d fo ra portio n o f

th e Sit e groundwater , referre d t o a s th e T l Zon e (includin g an d surroundin g th e TWAI I Area) , wher e concentration s o f VOC s (e.g. , benzene , 1,4-dichlorobenzene ) an d PCB s excee d th e RO D targe t cleanu p goal s an d curren t ARARs . USEP Aha s indicate d th e T l waive rwil l b e par t of a RO D amendmen t tha t i s expecte d t o b e signe d i n Septembe r2002 . I n th e pas t 1 4 MO M samplin g events , neithe rbenzen e no rPCB s hav e bee n detecte d i n well s downgradien t of TWAII . Additionally , th e concentration s o f 1,4-dichlorobenzen e sho wa statisticall ysignifican t downwar d trend . 7.2. 3 OU-3 : Rigg s Broo k Change s i n Standard s an d TBCs . Guidanc e fo rsedimen t writte n afte r198 9 includ e sedimen t qualit ycriteri a publishe d byth e Nationa l Oceani can d Atmospheri cAdministratio n (NOAA) , th e Ontari o Canad a Ministr yo f Energy , USEP Aan d Oa k Ridg e Nationa l Laboratory . Thes e criteri a ar e include d i n Appendi xD a s TBCs . Althoug h thes e sedimen t criteri a ar e mor e conservativ e tha n th e RO D targe t cleanu p goa l o f 1 ppm , at th e tim e o f th e ROD , th e USEPA , U.S . Fis h an d Wildlif e Servic e an d NOA Aagree d that th e potentia l fo rirreversibl e environmenta l damag e cause d bysedimen t excavatio n t o achieve th e cleanu p goa l of 1 pp m outweighe d th e disadvantage s o f leavin g contaminate d sediment s i n place . Therefore , th e RO D se t a trigge r leve l o f 5 pp m which , i f exceeded , woul d require mor e rigorou s samplin g t o determin e th e need , i f any , fo rfurthe rremedia l action . Change s i n Exposur

e Pathways . Lan d us e i n th e Rigg s Broo k are a has not change d an d i s not expecte d t o change , an d there ar e n o additiona l route s o f exposure . Change s i n Toxicityan d Othe rContaminan t Characteristics . Th e majo rcontaminan t that ha s bee n historicall ydetecte d i n Rigg s Broo k sediment s i s PCBs . Th e curren t cance rslop e facto r fo rthi s contaminan t i s 7. 7 (mg/kg/d)" 1

. Th e origina l cance rslop e factor s fo rPCB s reference d i n th e Endangermen t Assessmen t wa s 7. 0 (mg/kg/d)" 1

. Althoug h thi s i s a sligh t increas e i n th e cance rris k

pose d byexposure to PCBs , monitorin g i s on-goin g i n Rigg s Brook , an d overal l concentration s o f PCB s see m t o b e decreasing . Change s i n Ris k

Assessmen t Methods . Since th e RO D wa s writte n i n 1989 , there hav e bee n som e change s t o th e ris k assessmen t method s fo rsediments . Th e majo rchang e involve d

RI02942 F 7-1 0 TetraTechNUS , Inc .derma l exposur e assumptions . However , sinc e Rigg s Broo k i s rarel yuse d fo rrecreation , an d sinc e th e level s o f contaminant s detecte d i n sediment s ar e fairl ylo wan d th e exposur e assumption s mad e i n th e Endangermen t Assessmen t wer e conservative , th e remed ystil l remain s protective . Expecte d Progres s Toward s Meetin g RAO . There hav e bee n periodi cexceedance s o f th e 5 pp m trigge rleve l fo rRGB s i n Rigg s Broo k sedimen t sinc e samplin g bega n i n 1996 . Supplementa l samplin g wa s undertake n t o determin e th e exten t o f sedimen t wit h thes e highe r levels . Th e exten t o f th e exceedance s wa s foun d t o b e verylimited . I n 2001 , concentration s o f PCB s slightl yexceede d th e targe t leve l a t on e location , an d wer e les s tha n 1 pp m a t al l remainin g locations . Concentration s o f PCB s i n biot a wer e belo wth e targe t leve l o f 2 pp m i n bot h th e 199 7 an d 200 0 samplin g events . 7. 3 Questio n C : Ha s An yOthe rInformatio n Com e T o Ligh t Tha t Coul d Cal l Into

Questio n Th e Protectivenes s O f Th e Remedy ? 7.3. 1 OU-1 : Sourc e Contro l Remedia l Actio n Th e OU- 1 SCR Awa s complete d wit h th e coverin g o f th e Designate d Are a wher e soil s wit h les s tha n 1 0 pp m PCB s wer e consolidated , an d th e subsequen t reestablishmen t o f vegetation . Therefore , Sit e soil s are no t accessibl e s o ther e i s n o potentia l fo rexposure . Sinc e n o ne w ecologica l target s wer e identifie d durin g th e five-yea rreview , th e monitorin g o f ecologica l target s i s no t necessary . N o othe rinformatio n ha s bee n discovere d that woul d cal l into questio n th e protectivenes s o f th e remedy . 7.3. 2 OU-2 : Managemen t o f Migratio n Th e mai n issu e i n OU- 2 i s th e T l Waive rbein g sough t fo rth e Designate d Area . Currently , concentration s o f Sit e contaminant s excee d bot h RO D targe t clean-u p goal s an d curren t ARARs . However , sinc e a T l Waive ri s currentl ybein g sough t t o provid e repriev e fro m thes e standards , at th e tim e o f thi s five-yea rrevie wth e protectivenes s o f th e MO M remed yshoul d no t b e calle d int o question . N o othe rinformatio n ha s bee n discovere d tha t woul d cal l int o questio n th e protectivenes s o f th e remedy .

RI02942 F 7-1 1 Tetra Tec h NUS , Inc .7.3. 3 OU-3 : Rigg s Broo k

Th e remed yselecte d fo rRigg s Broo k consiste d o f th e monitorin g o f contaminant s i n sediments . Ther e hav e bee n exceedance s o f clean-u p goal s fo rOU-3 ; however , ecologica l risks hav e bee n adequatel yaddresse d an d ther e i s on-goin g biot a monitorin g schedule d fo rRigg s Brook . Whil e thi s are a i s mappe d a s a Zon e Afloo d hazard area , i t ha s no t bee n affecte d b yan yfloodin g o r othe rweather-relate d event s an d n o othe rinformatio n ha s bee n discovere d that woul d cal l into questio n th e protectivenes s o f th e remedy . 7. 4 Technica l Assessmen t Summar y Accordin g t o th e dat a reviewed , th e sit e inspection , an d th e interviews , th e remed yi s functionin g a s intende d b yth e ROD , a s modifie d b yth e ESD . Ther e hav e bee n mino rchange s t o th e physica l condition s o f th e site , cause d b yerosion , bu t thes e change s d o no t affect th e protectivenes s o f th e remedy . Mos t ARAR s fo rsoil , groundwate ro rsedimen t contaminatio n hav e bee n met . There hav e bee n som e change s i n toxicit yfactors , mos t notabl yth e increas e i n th e CS F fo rRGBs , bu t th e change s hav e no t bee n significan t enoug h t o effec t th e origina l determinatio n o f ris k

i n th e ROD . Additionally , ther e hav e bee n n o change s t o th e standardize d ris k assessmen t methodolog ytha t coul d affect th e protectivenes s o f th e remedy . Finally , there i s n o othe rinformatio n fo ran yo f th e OU s tha t call s int o questio n th e protectivenes s o f th e remedy . 7.4. 1 OU-1 : Sourc e Contro l Remedia l Actio n Th e SCR Awa s complete d i n accordanc e wit h th e RO D throug h th e excavatio n an d offsit e disposa l of soi l an d sedimen t wit h greate rtha n 1 0 pp m PCBs , an d th e consolidatio n an d coverin g o f soi l wit h les s tha n 1 0 pp m PCB s int o th e Designate d Area . Additionally , O& M cost s hav e remaine d lowe rtha n origina l estimates . Mos t ARAR s that appl yt o soi l o n Sit e hav e bee n met pursuan t to th e ROD , an d additiona l TBC s identifie d since th e RO D have als o bee n met . Lan d us e at th e Sit e ha s no t change d ove rth e years , no ri t i s expecte d t o i n th e future , therefor e al l exposur e pathway s identifie d remai n valid , an d n o ne wpathway s hav e emerged . Althoug h som e toxicityvalue s fo rcontaminant s o n Sit e hav e changed , th e chang e woul d no t impac t th e outcom e o f th e origina l Endangermen t Assessmen t sinc e ther e woul d b e n o significan t chang e

RI02942 F 7-1 2 Tetra Tec h NUS , Inc .i n cance rrisks at th e Site . Wit h th e completio n o f th e SCRA , th e remedia l actio n goal s fo rOU- 1

wer e met . 7.4. 2 OU-2 : Managemen t o f Migratio n A s describe d i n previou s sections , document s an d samplin g result s fo rth e MO M portio n o f th e Sit e sho wtha t th e remed yi s functionin g a s intended , wit h th e exceptio n o f th e TWAI I Are a wher e PCB s an d VOC s excee d thei rcleanu p limits . Ther e hav e bee n n o additiona l O& M cost s beyon d th e origina l scop e o f work . Th e Declaratio n o f Restrictiv e Covenant , tha t i s bein g hel d i n escro wb yth e MEDEP , prevent s exposur e t o contaminate d Sit e groundwater . Th e on e significan t chang e i n standard s affectin g th e statu s o f OU- 2 i s th e chang e i n th e ME G fo rPCBs . Thi s chang e decrease d th e ME G b yon e orde ro f magnitude , therefor e makin g i t more conservativ e tha n th e Sit e clean-u p goa l establishe d i n th e ROD . On e ne wpotentia l exposur e pathwa yidentifie d sinc e th e RO D i s th e indoo rpathwaythat woul d exis t i f building s wer e constructe d on-site . However , there ar e currentl yn o plan s fo ran yon-sit e constructio n an d al l previousl yidentifie d pathway s remai n valid . Ther e wer e som e change s i n toxicit ydat a fo rSit e contaminants , howeve ronl yth e CS F fo r PCB s indicate s a slightl ygreate rris k o f cance rtha n previousl ydetermined . Sinc e th e chang e i s insignificant , th e origina l assessmen t remain s valid . 7.4. 3 OU-3 : Rigg s Broo k Documen t an d dat a review s fo rRigg s Broo k indicat e that th e remed yi s functionin g a s intende d b yth e RO D an d RSOW . Th e institutiona l control s implemente d fo rth e res t o f th e Sit e als o appl yt o OU-3 . Durin g th e mos t recen t roun d o f sedimen t samplin g conducte d i n 2001 , concentration s o f PCB s slightl yexceede d th e trigge rlevel , reachin g 6. 1 pp m at on e location , an d wer e les s tha n th e 1 pp m targe t cleanu p goa l at al l remainin g locations . Concentration s o f PCB s i n biot a wer e belo wth e threshol d leve l o f 2 pp m i n bot h th e 199 7 an d 200 0 samplin g events . There ar e severa l TB C document s that wer e reviewe d fo rthi s repor t that provid e guidanc e i n establishin g sedimen t standards . Althoug h ther e hav e bee n exceedance s o f th e 5 pp m trigge r

RI02942 F 7-1 3 Tetra Tec h NUS , Inc .level , i t wa s determine d b yth e EPA , th e U.S . Fis h an d Wildlif e Servic e an d NOAAtha t leavin g

contaminate d sediment s i n plac e woul d caus e les s har m t o th e ecosyste m tha n performin g a n excavation . As wit h th e othe rOUs , th e chang e i n th e CS F fo rPCB s woul d slightl yalte rth e ris k value s fo rsediments , howeve rno t enoug h t o alte rth e protectivenes s o f th e remedy .

RI02942 F 7-1 4 Tetr a Tec h NUS , Inc .8. 0 ISSUE S

A s discusse d previously , th e groundwate ri n th e TWAI I are a o f th e Sit e i s bein g impacte d b y residua l oi l an d i s no t achievin g th e groundwate rcleanu p goals . Areques t fo ra T l waive ri s currentl yunde rrevie wb yth e EP Aan d MEDEP . Therefore , th e OU- 2 remed ya s currentl y constitute d i s no t protective . Groundwate ri n othe rportion s o f th e Sit e i s showin g decreasin g trend s i n targe t cleanu p levels . Whil e there mayb e opportunitie s t o optimiz e OU- 1 O& M activitie s an d OU- 3 annua l samplin g activities , th e remedie s are currentl yprotectiv e an d are expecte d t o continu e t o b e protectiv e i n th e future . Th e Rigg s Broo k

sediment s d o no t consistentl ymee t th e targe t cleanu p goal . Th e annua l sediment-monitorin g progra m i s planne d t o continu e unti l 2006 . A s par t o f th e five-yea rrevie w process , MEDE P ha s expresse d concern s that th e targe t cleanu p goa l o f 1 pp m fo rth e Rigg s Broo k sedimen t se t i n th e 198 9 RO D mayno t adequatel yaddres s ecologica l risk . MEDE P als o no wdisagree s wit h th e statemen t tha t sedimen t excavatio n woul d caus e irreversibl e damag e t o th e Rigg s Broo k

wetlands . Th e chang e i n ARAR s fo rOU2 , specificall yth e promulgatio n of th e 199 2 ME G fo rPCB s i s a n issu e tha t shoul d b e addressed . Th e 199 2 ME G (0.05 ppb) i s significantl ylowe rtha n th e 1989 RO D targe t clean-u p goa l of 0. 5 pp b fo rPCBs . Althoug h i t ma ynot affect th e overal l protectivenes s of th e remedy , th e 199 2 MEG s fo rPCB s remai n enforceable . Therefore a reevaluatio n of th e OU- 2 targe t leve l fo rPCB s i n groundwate ri s warranted . Th e reevaluatio n woul d serv e a s a n assuranc e that th e cleanu p goa l fo rPCB s remain s protective of huma n healt h an d th e environment . Tw o location s i n th e Source Contro l are a include d i n th e 200 0 sedimen t samplin g gri d exceede d th e 1 pp m PC B cleanu p level . Since thi s portio n of th e Sit e wa s not covere d wit h 1 2 inches of clea n soil , thes e location s shoul d b e resample d durin g th e 2002 Rigg s Broo k sedimen t monitorin g even t t o asses s th e potentia l fo rexposure . There i s presentl yn o agency-approve d O& M Plan . A n update d Pla n i s bein g prepare d byCMP .

RI02942 F 8- 1 Tetr a Tec h NUS , Inc .

### Th e 0.2-acre shortfal l i n post-restoratio n wetlan d are a i s a n issu e tha t wil l b e closel ymonitore d durin g th e year s 5 an d 1 0 events . Thi s doe s no t affec t th e curren t protectivenes s o f th e remedy . Restriction s o n groundwate rus e a t th e Sit e shoul d b e reevaluate d a s a resul t o f th e T l waiver .

RI02942 F 8- 2 Tetra Tec h NUS , Inc .9. 0 RECOMMENDATION S AN D FOLLOW-U P ACTION S

Th e approva l o f th e PRP' s T l Waive rwil l resul t i n revisio n th e ARAR s fo rOU- 2 an d a modificatio n of th e remed yvi a a RO D amendment . Thi s proces s i s currentl yunderwa yby USEP A wit h th e suppor t of MEDEP . Thi s an d othe rissue s an d action s require d ar e summarize d i n th e tabl e below . Issu e OU- 2 Cleanu p goal s no t achievabl e i n TW AI I are a PC B ME G (0.0 5 ppb) S C sampl e exceedanc e o f 1 pp m PC B leve l O& M Pla n Shortfal l i n restore d wetlan d are a Restriction s o n future groundwate r us e Recommendations / Follow-u p Action s Implemen t necessar

y regulator ychange s t o th e remed yfo rOU- 2 Analyz e groundwate r at lowe rD L t o determin e i f remed y meet s th e PC B ME G Resampl e th e tw o location s fro m th e 200 0 EPA gri d Updat e O& M Plan , obtai n agenc

y approva l Regulator

yoversigh t o f year S an d 1 0 event s Reevaluat e th e Institutiona l Control s an d restructur e t o reflect curren t Sit e condition s Party Responsibl e EP A CM P CM P CM P CM P EPA/Stat e Oversigh t

Agency Stat e State/EP A State/EP A State/EP A State/EP A CM P Mileston e

Dat e Septembe r 200 2 Septembe r 200 2 Fal l 200 2 Summe r 200 2 200 7 Septembe r 200 2 Affect s

Protectiveness ? (Y/N ) Curren t Y

N

N

N N Y Future

Y

N

N

N N Y

RI02942 F 9- 1 Tetra Tec h NUS , Inc .10. 0 PROTECTIVENES S STATEMENT S

OU-1 : Th e remedia l actio n fo rOU- 1 ha s bee n complete d an d i s protectiv e o f huma n healt h an d th e environment . Exposure pathway s tha t coul d resul t i n unacceptabl e ris k are bein g controlled . Th e finalizatio n o f th e O& M pla n wil l ensure that th e OU- 1 remed ywil l remai n protective . OU- 2 : Th e remed yat OU- 2 i s no t protectiv e i n th e TW AI I are a o f th e Sit e an d surrounding s define d a s th e T l Zon e i n th e T l Waive rdu e t o th e presenc e o f residua l oi l i n th e subsurfac e an d PC B an d VO C concentration s tha t ca n no t mee t targe t cleanu p levels . Action s no wunderwa y t o implemen t th e T l Waive rar e neede d t o ensur e protectiveness . OU- 3 : Th e remed yat OU- 3 i s expecte d t o b e protectiv e o f huma n healt h an d th e environmen t upo n completio n o f th e 10-yea rsamplin g program . I n th e interim , exposur e pathway s that coul d resul t i n unacceptabl e risks are bein g monitored . Th e annua l sedimen t monitoring , whic h bega n i n 1996 , ha s foun d periodi can d isolate d exceedance s abov e th e 5 pp m trigge rlevel . Additiona l samplin g an d ho t spo t excavatio n i n 199 7 indicate d tha t th e exceedance s are limite d areall yan d ove rtime . Th e biot a samplin g ha s indicate d tha t th e remed yfo rOU- 3 i s protectiv e o f huma n health , an d wit h th e anticipate d continue d decreas e i n dissolve d PC B concentration s i n th e dischargin g groundwater , th e remed yi s expecte d t o remai n protectiv e o f huma n health .

RI02942 F 10- 1 Tetra Tec h NUS , Inc .11. 0 NEX TREVIEW Asecon d five-yea rrevie wfo rth e O'Conno rSite wil l b e conducte d i n 2007 .

RI02942 F 11- 1 Tetra Tec h NUS , Inc .APPENDI X A DOCUMEN T REVIE W LIST/REFERENCE SDOCUMENT S REVIEWED/REFERENCE S CITE D

Cityo f Augusta , ME , Lan d Us e Ordinance . Floo d Insuranc e Rat e Map , Cityo f Augusta , Maine , Kennebe cCounty , Community-Pane l Numbe r23006 7 001 1 C . Jun e 15 , 1994 . IC F - Clement , Inc. , 1988 . Endangerment Assessment

fo r th e O'Connor

Site i n Augusta, Maine. Th e Smar

t Associates , 2000 . 1999 Wetland

Construction

Monitoring

Report, O'Conno r Compan ySite , Augusta , Maine ; Augus t 15 , 2000 . Th e Smar

t Associates , 2001 . 200 0 Wetland Construction

Monitoring

Report, O'Conno r Compan ySite , Augusta , Maine ; Marc h 13 , 2001 . USEPA , 1989 . Record o f Decision

Summary, U.S . Environmenta l Protectio n Agency , Regio n 1 , Boston , Massachusetts , Septembe r1989 . USEPA , 1990 . Guidance o n Remedial

Actions fo r Superfund

Sites with PCB Contamination, OSWER Directive

No . 9355.4-01. Augus t 1990 . USEPA , 1991 . "Consent Decree - United States o f America, Plaintiff

v . Central Maine Power Company, Defendant."

Septembers , 1991 . USEPA , 1994 . Declaration for th e Explanation

o f Significant

Differences, O'Conno rCompan y Superfun d Site , Augusta , Maine , Jul y11 , 1994 . USEPA , 1995 . Invocation o f Contingency

Remedy, O'Conno rCompan ySuperfun d Site , Augusta , Maine , Octobe r10 , 1995 . USEPA , 2001 . Comprehensive Five-Year

Review Guidance, OSWER

Directive

9355.7-03B-P. Jun e 2001 . U S Fis h & Wildlif e Service , 2001 . Comment s o n Th e Smar t Associates , 200 0 Wetland s Constructio n Monitorin g Report . Jun e 29 , 2001 . Woodar d & Curran , 1996 . Source Control Remedial

Action Community

Relations

Plan, Woodard & Curran , Inc. , Jul y1996 . Woodar d & Curran , 1997 . Data Collection

an d Interpretation

o f th e Phase I I Operation

o f th e Vacuum Enhanced

Recovery

(VER) System at the O'Connor

Site in Augusta, Maine, Woodar d & Curra n Inc. , Jun e 27 , 1997 . Woodar d & Curran , 1999 . MO M Sampling

an d Analysis

Quarterly

Report, March

1999, O'Conno rCompan ySuperfun d Site , Augusta , Maine , Jun e 8 , 1999 . Woodard & Curran , 2000 . Draft Request

fo r Technical

Impracticability

Waiver fo r OU-2 Management

o f Migration, O'Conno rCompan ySuperfun d Site , Augusta , Maine , Apri l 2000 .Woodar d & Curran , 200 1 a . Revised Long-Term

Groundwater

Quality Monitoring

Program

an d Phase III VE R Work Plan, O'Conno rCompan ySuperfun d Site , Augusta , Maine , Jul y25 , 2001 . Woodar d & Curran , 200 1 b . 2000 Riggs Brook Sediment

an d Biota Monitoring

Report, O'Conno r Compan ySuperfun d Site , Augusta , Maine , Jul y2001 . Woodar d & Curran , 200 1 c . MO M Sampling

an d Analysis Quarterly

Report, O'Conno rCompan y Superfun d Site , Augusta , Maine , Octobe r26 , 2001 . Woodard & Curran , 200 1 d . Draft VE R Phase III Report, O'Conno rCompan ySuperfun d Site , Centra l Main e Powe rCompany , Augusta , Main e Decembe r2001 . Woodard & Curran , 200 1 e . 200 7 Riggs Brook Sediment

Monitoring

Report, O'Conno r Compan ySuperfun d Site , Augusta , Maine , Decembe r2001 . Woodar d & Curran , 2002 . Draft O'Connor

Superfund

Site Five-Year

Review Document. Apri l 2002 .APPENDI X B SIT E INSPECTIO N REPOR TO'Conno r Compan y Site Inspectio n - Ma y 22 , 2002 Fiv e Yea r Review , WA # 123-FRFE-013 3 Attendees : Nanc ySmit h - EP A WA M Terr yConnell y- EP A RP M Wilke s Harpe r- MEDEP , Projec t Manage r HankAndolsek-MEDEP , Geologist Phoeb e Cal l - TtNUS , EP A Contractor , Projec t Manage r Kati e Lan g - TtNUS , EP A Contractor , Projec t Scientis t Ro yKoste r- Centra l Main e Power , Senio rEnvironmenta l Specialis t Joh n Carrol l - Centra l Main e Power , CommunityRelation s Specialis t Lor i Morea u - Woodard & Curra n - R P Contracto r Th e Sit e Inspectio n commence d at approximatel y9:1 0 A M an d conclude d approximatel y11:30 AM . Weathe rwa s sunny , approximatel y6 0 degrees . Observation s mad e b yth e EP A contracto ran d othe rparticipants ar e note d below . Followu p interview s wit h sit e inspectio n participants wil l b e mad e a t a late rdate . Fiel d Notes : Th e Sit e i s n o longe rsecure d wit h fencing . Th e fenc e wa s remove d fro m th e active treatmen t area s afte rth e clea n fil l cove rwa s place d ove rth e excavate d area s an d seedin g wa s completed . Th e dir t acces s roa d i s i n goo d repair . Th e Sit e appears a s wel l vegetate d rollin g hills , wit h a n uplan d mars h an d tw o downgradien t restore d wetlan d areas . Th e Sit e i s unattended . N o signag e wa s observe d eithe ridentifyin g th e Sit e o rrestrictin g access . Th e vegetatio n i s wel l established ; mowin g has generall yno t bee n required . Monitorin g well s were eas yto locat e since theyhave hig h stickups . Mowin g migh t b e require d i n th e summe rmonth s t o ensur e acces s t o well s a s require d fo rongoin g monitorin g activities . N o record s ar

e retaine d a

t th e Site . Ther

e i s n o treatmen t equipment , piping , etc . remainin g a t th e Site . There ha s bee n n o documente d vandalis m o rtrespassin g o n th e Site , eithe rbefor e o rafte rth e perimete rfenc e wa s i n place . Th e remainin g monitorin g well s are no t al l secure d wit h wel l locks . Th e Yea r5 wetlan d restoratio n monitorin g even t wil l take place thi s year . CM P personne l chec k

th e Sit e an d th e well s i n th e TW AI I are a fo rfloatin g oi l o n a monthl y basis . Oi l i s collecte d wit h absorben t pads , whic h are take n of f sit e t o a CM P transfe rfacilit yi n Augusta . N o hazardou s material s ar e store d o n th e Site .Th e oi l remainin g i n th e TW AI I are a i s i n a verytigh t clayformation . Last yea rth e vacuum enhance d recover

y(VER ) operatio n recovere d 2 0 gallon s o f oil . CM P personne l state d tha t 1 7 gallon s wer e recovere d fro m th e bedroc k an d 3 gallon s fro m shallo wwells . Th e R P contracto rnote d tha t du e t o th e geolog yo f th e are a there i s n o overburde n aquifer . I n som e area s that wer e excavate d t o a dept h of 1 2 fee t durin g source contro l groundwate rwa s no t encountered . Du e t o th e clay s perche d groundwate rexists . Th e pendin g T l waive ran d RO D amendmen t fo rOU 2 wa s discusse d at length . Issue s a s t o th e boundarie s o f th e 'designate d area' , are a covere d b yth e T l waiver , etc . hav e ye t t o b e settled . Th e waive rwil l acknowledg e that th e groundwate ri n tha t are a (onc

e boundarie s ar

e set) ca n no t b e cleane d u p a s originall yenvisioned , bu t effort s wil l likel ycontinu e usin g VE R a s lon g a s th e proces s continue s t o remov e oil . CM P personne l note d tha t ol d aeria l photo s showe d th e are a a s ope n fields . I t i s though t tha t th e curren t ope n area s of th e Site existe d durin g sit e operation s an d wood s becam e establishe d i n undisturbe d area s o f th e site . N o tree s wer e remove d durin g th e remedia l activitie s at th e Site . Whe n th e tw o lagoon s wer e dewatere d an d remediated , a swal e wa s constructe d t o guid e overlan d flo wfro m th e lagoon s dow n th e stee p slop e towar d th e wetland s surroundin g Rigg s Brook . Th e reconstructe d lagoo n embankment s an d swale s wer e i n goo d repair . Ne wdevelopmen t i n August a i s o n th e wes t sid e o f th e Kennebe cRiver . Th e Sit e i s o n th e eas t sid e an d there has bee n n o newdevelopmen t alon g Rout e 1 7 i n th e are a of th e Site since remedia l activitie s began . Th e onl yne wstructure observe d wa s a hom e o n to p o f a nearb yhil l recentl yconstructe d o n lan d formerl yowne d b yCM P eas t o f Rigg s Brook . Durin g th e sourc e contro l excavation s som e monitorin g well s ha d t o b e decommissioned . Th e Superfun d Sit e boundar yi s th e sam e a s th e boundar yi n th e Restrictiv e Covenan t betwee n CM P an d MEDEP . Thi s are a encompasse s 2 3 acres ; th e 'designate d area ' i s abou t 3 acres . A Restrictiv e Covenan t ha s bee n signe d b ybot h partie s an d i s bein g hel d b yMEDEP . Thi s documen t provide s institutiona l control s limitin g groundwate rus e whil e activ e remediatio n i s underway . Samplin g o

f biota an d sedimen t i n Rigg s Broo k has show n PC B contaminan t concentration s i n fis h an d frog s belo wth e standards . Ther e hav e bee n a fe wsedimen t ho t spot s containin g PC B concentration s jus t ove rth e applicabl e standard identifie d durin g th e annua l sedimen t sampling . Th e Sit e wa s regrade d t o matc h th e origina l contour s a s closel ya s possible . Th e soi l cove ri s wel l vegetated . There were n o area s of erosio n noted . CM P personne l perfor m sit e inspection s twic e annuall yan d documen t thei robservations . Ther e wer e man ybird s observed , especiall yi n th e wetlan d areas . Agarte rsnak e wa s foun d o n th e slop e betwee n th e forme ruppe ran d lowe rlagoons . O& M cost s hav e bee n provide d byth e R P contracto ra s par t of thei rinformatio n fo rth e five-yea r review .Th e remedie s a s currentl yimplemente d are effectiv e an d functionin g a s designed . As note d

abov e th e TWAI I are a i s th e subject o f a T l waive rreques t fro m CMP . Pos t sourc e contro l R A activitie s continue , groundwate rmonitorin g continue s o n a semi-annua l basis . Oi l i n well s i n th e TW AI I are a i s remove d o n a monthl ybasi s whe n evident . VE R wil l likel ycontinu e a s lon g a s i t i s effectiv e i n removin g additiona l oil . AUGUST A MUNICIPA L OFFICE S - CITY SERVICE S DEPARTMEN T Obtaine d floo d plai n map s an d zonin g map s fo rth e are a o f th e Site . Th e cler k kne wof th e Sit e an d it s locatio n bu t wa s not familia rwit h details . LITHGO W PUBLI C LIBRAR Y Personne l a

t th e librar

yconfirme d that th e O'Conno rSite documents ar e i n th e basemen t of th e library . Individual s hav e accesse d the m i n th e past , bu t no t hav e no t don e s o recently .O'CONNO RSITE INSPECTIO N PHOTOGRAPHI C RECOR D

Photo No. : 1

Date : 5/22/0 2 Comments : At

the hig hpoin

t o f the Sit e a t the TWA III area , o n the road , lookin g towar

dRout e 17 .

Phot o No. : 2 Date : 5/22/0 2 Comments : Towar

dthe wetlan dare a wes t of th e acces s road .



### Original s i n color .O'CONNO RSITE INSPECTIO N PHOTOGRAPHI C RECOR D Phot

o No. : 3 Date : 5/22/0 2 Comments : Fro mth e TWA n are a towardthe lowe

r lagoon .

Phot o No. : 4 Date : 5/22/02 Comments : Fro mthe lowe r lagoon are alooking towar

dRigg s Brook

and it s wetlands .



### Original s in color .O'CONNO RSITE INSPECTIO N PHOTOGRAPHI C RECORD Phot o No. : 5 Date : 5/22/0 2 Comments : Standing on the concret e dam n a t the endo f

the uppe r lagoon looking east

towar dthe lowe

r lagoon andRigg s Brook .

Phot o No. : 6 Date : 5/22/0 2 Comments : A

t the top o f the swale wit hback to the upper

lagoon .



### Original s i n color,O'CONNO RSITE INSPECTIO N PHOTOGRAPHI C RECORD

Phot o No. : 7 Date : 5/22/0 2 Comments : Uplan dwet

are a

Phot o No. : 8 Date : 5/22/0 2 Comments : Uppe

r lagoon/wetland



### Original s in color

.O'CONNO RSITE INSPECTIO N PHOTOGRAPHI C RECOR D

Phot

o No. : 9 Date : 5/22/0 2 Comments : On Rout

e 1 7 en dof acces s roa dfacin g uphill .



### Original s in color

.APPENDI X C SIT E INTERVIE W LISTINDIVIDUAL S INTERVIEWE D FO R TH E O'CONNO R FIVE-YEA R REVIE W Name/Positio n Willia m Bridgeo

/ City Manage r Joh n Carroll / CommunityRelation s Specialis t Wilke s Harper/Project Manage r Ro yKoster/Senio r Environmenta l Specialis t Stev e Mierzykowski / Biologis t Lor i Moreau/PR P contracto r Horac e Rodrigue

/ neighbo r Cornel l Rosi u Organization/Locatio n Cityo f Augusta , M E Centra l Main e Power/Augusta , M E Main e DEP/Augusta , M E Centra l Main e Power/Augusta , M E U S Fis h & Wildlif e Service/Ol d Town , M E Woodar d & Curran./Portland , M E Con yRoad , Augusta , M E USEPA/Boston , M A Date * Jun e 3 , 200 2 May22 , 200 2 & Ma y29 , 200 2 May22 , 200 2 & Jun e 10 , 200 2 Ma y22 , 200 2 Jun e 19 , 2002 Ma y22 , 200 2 & Ma y29 , 200 2 Jun e 3 , 200 2 Jun e 20 , 200 2 * May22 , 200 2 interview s wer e conducte d durin g th e sit e inspection ; al l othe r interviews wer e conducte d vi a telephone .

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### APPENDI XE

DECLARATIO N

O F RESTRICTIV

E COVENAN T AN D MA P SHOWING ARE A COVERE D B Y COVENAN T

### AGREEMENT . RELEAS FAN D STTPT n ATTO N



### Thi s Agreement , Releas e an dStipulatio n i s entere damon g th e State o f Maine an d Main e Departmen t

o f Environmenta

l Protectio n (collectively calle d"Department" ) an d Centra l Main e Power

Company , Inc . ("CMP") , fo r th e purpose s o f

resolvin g claim s b y th e Departmen t

agains t CM P arisin g fro mcondition s o n aparce l o f real property , mor e particularly , describe din th e attache dDeclaratio n o f Restrictiv e Covenant , whic hparce l CM P own s an dwhic hparce l th e Departmen t ha s designate da s a

n "uncontrolle d hazardou s substanc e site " pursuan t t o 3 8 M.R.S.A . § § 136

4 - 1365, an

dattachin g condition s to sai dparce l o f

rea l property . For purpose s o f

thi s Agreement , an dno t t o b e construe da s a

n admission b y any party , but subjec t to th e condition s an dlimitation s set forthbelow , CM P an dth e Departmen t

hereb y agre e an dstipulate a s follows : 1 . CMP i s recor

downe r o f tw o parcel s o f

property locate don Easter n Avenue , so-called(Stat

e Route 17 ) i n Augusta , Kennebe c County , Maine . Sai dparcel s ar e mor e particularl y describe di n the-attache dDeclaratio n o f Restrictiv e Covenant

A portio n o f th e aforesai dparcel s ha s bee n designate db y th e Department a s a n uncontrolle dhazardou s substanc e sit

e pursuan t

t o 3 8 M.R.S.A . § § 136

4 an d136 5 due t o th e presenc e i

n th e soil s on th e Sit e an dth e groundwate f

under th e Sit e o f PCBs , polyaromati c hydrocarbon s (PAHs) , . an dlead , al l o f

whic hare hazardou s substance s under Main e an dFedera

l law . This same portio n ha s been liste do n th e National Prioritie s Lis t a s a"Superfun dSite " b y th e Unite d State s Environmenta

l Protectio n Agenc y ("EPA") . The designate dportio n shall hereinafter

b e referre dto a s th e "Site" . 2 . A s agenerator

o f the lead , PCB s andPAH s who arrange dt o dispos e o f

thes e hazardou s substance s a

t the Site , CMP ha s been identifie da s one o f the partie s liable t

o remediate th e Sit

e b y both-th e Department an dEPA . 3 . The Sit

e i s bein g cleanedu

p under aConsen t Decree agree dt

o b y CMP and EPA o n Novembe

r 23,1990, whic hwa s entere db y the Unite dState s District .Cour t for the District o f Maine o n Septembe

r 3,1991 , a

t Unite dStates ^ e t

si. v . Central M?me Powe r Company ; Civi

l Actio n No . 92-0302-B . Pursuant t o thi s Consen

t Decree , CMP will remediat e th e contaminate dsoil s an dsurfac e wate r o n th e Sit

e an dcontaminate d groundwater

under th e Sit e usin g method s approve db y th e EPA , afte r opportunit

y fo r revie w an dcommen

t b y th e Department . Th e treatmen t technologie s an dcleanu

p level s for lead , PCB s andcPAH s a t the Sit e ar e set forthin me Recor

dof Decisio n ("ROD" ) issued b y EPA . EPA propose s to adjus t certai n cleanup level s i n adocument identifie da s th e Explanatio n o f

Significant

Differenc e (ESD) . •* ! • ''

' \ : ; . • _. . . . 

### 4 . The RO D state s that on-sit e soil s will b e treate dusing solven t extraction , s o a s to reduc e the level o f

PCB s an dcPAH s to on e part pe r million (ppm) . 5 . Whil e it

i s feasibl e t

o readvthl s cleanup leve

l for PCB s in the les s contaminate dsoil s o n site , informatio n whic hcam e to light after th e RO D wa s initiall

y

### •2-



### acprove dindicate s that

i t wil l neither

b e technically feasibl e no r cos t effectiv e t o achiev e th e on e pp mcleanu p leve l usin g th e specifie dsolvent extractio n metho dfo r

th e more contaminate dsoils . I n addition , EPA ha s determine dtha t level s o f 1 0 pp mo f

tota l PCB s an d10-pp mo f

total cPAH s fall s withi n th e ris k rang e whic hi s protectiv e o f huma n health . Fo r thes e reasons , th e soil cleanu p level s se t forthi n th e RO D wU l b e adjuste dby-EP A b y us e o f th e ESD , such that

th e soil treatmen t

metho dset

forthi n th e RO D will b e use donl y o n soil s withcontaminant level s greater

than 1 0 ppm . an dwill terminat e whe n the residual .level s o f

the PCB s andcPAH s ar

e lowere dt

o 1 0 ppm . In order

t o protec t th e environment , however , on-sit e soil s containin g level s o f total PCB s an dtota l cPAH s o f betwee n 1 pp man d1 0 pp mwill b e covere dwithclea n soil " fro mof

f sit e sources , t o th e thicknes s o f

12. inche s a s specifie din the ESD . The Departmen t agree s that

asoi l cover 1 2 inche s or greater meet s the Department' s ris k criteri ao f

10 ^ provide dthat

the cove r i s . maintained . 6 . Pursuan t

to th e Consent

Decree , followin g Site inspectio n an dsubmissio n o f awritte n report

signe db y th e CMF s Projec t Coordinator , an daregistere dprofessional engineer , certifyin g .tha

t al l remedial activitie s hav e bee n complete di n .full satisfactio n o f th e requirement s o f

th e Consent

Decree , an dEPA' s agreemen t wit h thi s finding , EPA will certif y completio n o f

the remedia

l work . 7 . Natura l resource s o f the State o f

Maine , includin g the groundwater tinde r the Site , hav e bee n damage db y contaminatio n a t th e Site . 8 . Under

both:Sectio n 107 of

CERCLA , 4 2 U.S. C § 9607 , an dMaine's . Uncontrolle dSite s Law , 3 8 M.RS.A . § 136 7 (1989) , the State o f

Main e ha s acaus e o f

actio n agains t CM P for damage s for-injur y to , destructio n o f or los s o f natural resource s o f

the State . 9 . Us e o f

th e groundwater

beneathth e Sit

e prio r to th e completio n o f " remediatio n activitie s coul dpos e risk s to th e publi c healt h an d'imperi l th e timel y remediatio n o f

th e Site . Likewise , other on-sit e activitie s coul ddisrup t remedia l or monitorin g measure s installed , pursuan t to th e Consent

Decre e o r

imperi l th e ongoin g adequac y o f

th e remediatio n implemente dunder th e Consent

Decree , including , withou t limitation , the dea

n soi l ca p describe dabove . In order to avoi dthe possibilit

y o f any suc h interferences , i t

i s necessar

y fo r CM P to fil e aDeclaratio n o f Restrictiv e Covenan

t i n th e for mattache dhereto a s Exhibi t 'A . NOW , THEREFORE , A . Th e effectiv e dat e o f thi s Agreemen t

shal l b e th e dat e upo n whichEPA issue s 

### th e 

### ESD . B . Withi n thirty (30 ) day s o f th e effectiv e dat e o f

thi s Agreement , CM P shall pa > th e su mo f

On e Hundre dTwenty-Fiv e Thousan dDollar s (5125,000.00 ) i n ful l-3 -



### cotnpensatio n fo r

th e natura l resourc e damage s describe dabove . Paymen t shall b e mad e b y acheck

mad e payabl e to th e "Maine DE P Uncontrolle dHazardou s Substanc e Fund. " Thi s check

shall b e delivere dwithi n the time specifie dto the Director , Division o f Sit e Investigatio n an dRemediation , Burea u o f Hazardou s Material s an dSolidWaste Control , Stat e Hous e Statio n #17 , Augusta , Main e 04333 : C Withi n thirt

y (30 ) day s o f

th e effectiv e dat e o f

thi s Agreement , CM P shal l date , execute an ddeliver t o th e Departmen t

fo r it s acknowledgement , aDeclaratio n o f Restrictiv e Covenant

i n th e for mattache dheret o a s Exhibi t A . Th e Departmen t

shall acknowledg e an dexecute th e Declaratio n an dhol dth e Declaratio n i n escro w unti l th e "completio n o f

the remedia l action " b y CM P a s that phas e i s define dan duse di n the above-reference dConsen t Decree . Th e Departmen t shall the n fil e th e execute d Declaratio n i n th e Kennebe c Count y Registr y o f Deeds . In consideratio n o f

CMP' s ful l an dtimely complianc e wit hthe term s o f

thi s Agreement , an di n consideratio n o f CMP' s ful l an dtimely complianc e wit hall term s an d provision s o f

the Consen

t Decre e it entere dwit

hthe Unite dState s Environmenta l Protectio n Agency , a s describe dabove , the Department release s anddischarge s CMP , it s principals , successors , assigns , paren t corporations , subsidiaries , affiliates , agents , servant r employees , attorney s anddirector s fro mall actions , suits , cause s o f action*'claims and demand s whatsoever , whic h th e Department no w has/or , but

fo r th e execution o f

thi s Agreement , couldor

might have , agains t

CMP , b y reaso n o f

or in respec t

t o the contaminatio n o f

the Site describe di n an daddresse db y the Consen t Decree . CM P release s th e Departmen t an dth e State o f

Main e fro many an dal l actions , suits , cause s o f action , claim s o r

demand s whatsoever

whic hi t might have , o r bu t fo r th e executio n o f

thi s Agreement , coul do r might hav e had , agains t

th e Department

an dth e Stat e o f Main e b y reaso n or

i n respec t

to th e contaminatio n o f

th e Site describe di n ari d addresse db y th e Consent Decree . Thi s Releas e shall becom e final an deffectiv e upo n ful l payment o f th e amount state di n paragrap hA above , th e filin g o f th e Declaratio n o f

Restrictiv e Covenan

t provide d i n paragrap hB abov e an dCMP' s ful l an dtimel y complianc e withth e Consen t Decree , including , withou t

limitation , EPA' s issuanc e o f al l certificate s o f

completio n calledfor

b y the Consen

t Decree . Thi s Releas e doe s no t

appl y to any perso n or

entit y no t asignator

y hereto an ddoe s no t appl y to any condition s other than thos e describe dabove . B y enterin g thi s Agreement , th e Departmen t doe s no t waiv e an dspecificall

y reserve s all o f

it s authority to addres s any condition s other than thos e describedabov e whic hmay b e discovere dat th e Sit e an dmay require additiona l work , •

### DECLARATIO N O FRESTRICTIV E COVENAN T

THE STAT

E O FMAINE )

, ) KNO WAL

LMEN B Y THES E PRESENT S THAT 

### COUNTY O FKENNEBE C ) . WHEREAS , Centra

l Maine Powe

r Company , aMain e corporatio n ("CMP") , i s recor downe

r o f tw o parcel s o f

propert y locatedo n Easter

n Avenue , so-calle

d(Stat e Rout e 17 ) in Augusta , Kennebe c County , Maine . .Parce l # 1 i s describe din aDee d fro mWillia

mR - O'Conno

r t o the . F . O'Connor

Company , date dApri l 1,197 7 and recorde din the Kennebec-Count y Registr y of Deed s in Boo

k 1987, Pag e 44 . Parcel #

2 i s describedin aDeedfro mCarroll E . Theriault andMar y J . Theriault

t o Robert,! . Husse y andJea n C . Hussey , date dAugus t 31,1973 andrecorde din the Kennebec ' • Count y Registr y of Deed s i n Boo k 1670 , Pag e 165 ; an

d

• WHEREAS , aportio n o f the aforesai dparcel s ha s bee n designatedas a

n Uncontrolle dHazardou s Substanc e Sit e pursuant

t o 3 8 MJIS.A . §§136

4 an d136 5 b y the Maine Department

o f Environmenta

l Protectio n ("DEP" ) an dha s bee n listedo n the Nationa

l Prioritie s List

a s a"Superfun dSite " b y the Unite dState s Environmenta

l Protection Agenc y ("EPA" ) andi s subjec t t o remediation pursuant t o aConsen

t Decree entere dbetween CM P an dEPA ; an d WHEREAS , a

n Agreement , Releas e andStipulation entere dinto b y CMP and DEP require s CMP t

o fil e aDeclaration o f

Restrictiv e Covenan

t in the Kennebe c Count y Registr y o f Deed s i n order

to ensur e the integrit

y o f certai n remedial measures ; NOW , THEREFORE , th e partie s hereto agre e that th e following covenant . shal l run wit h the lan dan db e bindin g upo n CM P an dit s successors an dassigns , andshal l apply t o the portio n o f

the CMP parcel s describedin Attachment A , which i s attache dhereto an dmad e apart hereof , an dwhich affecte dportio n shal l hereinafter

b e referre dto a s th e "Property " an dshal l b e effectiv e upo n th e "completion o f

the remedia

l action " b y CMP a s tha

t phras e i s define danduse din the above-reference dConsen t Decree : 1 . An y us e o f the groundwate r

beneat h the Propert

y shal l b e prohibite dwithout the prior writte n approva

l o f m e DEP . 2 . An

y activit y whic h might

disrup t remedia l or monitorin g measure s installe d pursuant to th e Consen

t Decre e shal

l b e prohibite dwithout

th e prio r

written , approval o f

the DEP . 3 . . CM P or

subsequent

owner shall maintai n th e Propert y i n aconditio n adequat e to ensur e the-conturue dcompliance , wit h Td l applicable cleanup standard s prescribe din , an dto ensur e th e ongoing adequac y o f th e.3 9 

### -2 - 

### remediatio n implemente dunde r th e Consent

Decree . B y wa y o f

example , an dno t b y wa y o f limitation , CM P o r

subsequen t

owne r shall maintai n al l drainag e ways , berms , monitorin g wells , permeabl e or imperviou s cap s or covers (includin g pave dportion s o f the propert

y an darea s coveredb y topsoil or othe r clean.fill) , piping , pump s an delectrica l equipment

constructe do r installedunder

the Consen

t Decree . 4 . The partie s hereto agre e that the restrictiv e covenant

herein shall b e perpetually bindin g upo n the Property , however , i f condition s o n the Propert y change , CM P or

any subsequen t

owne r o f the Propert

y ma y petitio n DEPfor consen t to the remova

l o f the restrictio n o n the Propert y created hereb y andthe terminatio n o f thi s Declaration o f

Restrictiv e Covenant . 5 . The restrictio n containe dherein shall only inure to the benefi t o f an dshall only b e enforceabl e b y DEP . N o owne r o f any propert

y or othe r thirdparry shall benefi t

fro mth e restrictio n containe dherei n o r hav e any right

o r standing t o enforc e same . 6 . B y it s executio n hereof , DE P acknowledge s andagree s ma t it ha s reviewe d andapprove do f

the 'matter s containedherei n andtha t thi s Declaratio n o f Restrictiv e Covenant

/ upo n bein g file di n the Kennebe c Count y Registr y o f Deeds , will satisf

y the applicable provision s o f the Agreement , Releas e and Stipulatio n i t

ha s entere dwit

hCM P regardin g th e Property . IN WITNES S WHEREOF , th e partie s heret o hav e execute dthi s Declaratio n o f Restrictive Covenan

t a s o f the - da

y o f , 1994. CENTRA LMAINEPOWE

RCOMPAN

Y By : 

### Name : Title : STAT EO FMAINE ' - ' KENNEBEC , ss . Personall y appeare dbefore m

e thi s da

y o f April , 1994

, the above-named an dmad e oat

hthat th e foregoin g i s tru e an d correc t an dbase dupo n his/her

persona l knowledge . NOTARY PUBLICD . E . P . flUGUSTf l ?3T -3 - 

### ACKNOWLEDGE

D AND DEPARTMEN

T O FENVIRONMENTA L PROTECTIO

N 

### Name : . Title : STAT EOFMAINE . ' KENNEBEC , ss . 

### Personall y appeare dbefore m

e tiu s da

y o f April , 1994

, th e above-named an dmade oat

htha t th e foregoin g i s tru e an dcorrect andbasedupo n his/he

r persona l knowledge . NOTARY PUBLIC

### I n addition , thi s i s withou t prejudic e t o th e Department' s righ t with respec t

t o al l matter s no t

describe dabove , includin g bu t no t limite dto , th e following : (1 ) Claim s base do n afailur e b y CM P t o mee t arequiremen t

o f thi s Agreement ; (2 ) Stat e la w claim s arisin g fro mafailur e b y CM P t o mee t arequiremen t

o f th e Consen t Decree ; (3 ) Liabilit

y fo r an y futur e uncompensate drespons e cost s whic h th e Departmen t may incur

wit h regar dt o th e Site . I t

i s no t presentl y contemplate dthat ther e will b e an y suc h respons e costs , i t bein g contemplate dtha t th e Unite dState s Environmental Protectio n Agency' s annual operation s gran t to th e State o f Main e shal l coveral l Stat e oversight cost s incurre dat

th e Site prio r

t o th e issuanc e o f

certificate s o f

completio n b y th e EP A unde r th e Consent

Decree . Notwithstandin g any othe r provisio n o f

thi s Agreement , Releas e an dStipulation , th e Departmen t

retain s al l authority an dreserve s al l right s to take any an dal l respons e action s authorize db y law an dt o seek reimbursement s fro mCM P o f cost s incurre db y th e Stat e i n takin g suc h respons e actions . DEPARTMENT O FENVIRONMENTAL PROTECTIO N DATED : ALA N M . PRYSUNk

A Director , Burea

u o f Hazardou s Material s & Soli dWaste Contro l STAT E O FMAINE KENNEBEC , ss . Personall y appeare dbefor e m e thi s JJ *&& day o f

June , 199

4 th e above-name dAla n M . Prysunka , an dmad e oath that th e foregoin g i atru e an dcorrec t an dbase dupo n hi s persona l knowledge . NOTAR Y PUBLI C

### u = i s 3.E.P . T32 S P.3 7

-O 

### MAINE POWE

RCOMPANY Geral dC . Pouli n Vic e President , Generatio n an d Technica l Suppor t STAT E OFMAINE KENNEBEC , ss . " DATED : Jun e 8 , 199 4

andbase dupo n hi s persona l taiowiedge . 

### a r..

NOT/iRY PUBUC

KARLAESVUASE Y Notary Public . Main * My Cornminien Expire * Apri l 1.200 1

## ATTACH : SEN T2 '•" • DEE D DESCRIPTIO N Th e followin g describe d parcel , situate d o n th e Northeasterl ysid e o f Stat e Rout e 17 , locall yknow n a s Easter n Avenue , i n th e cit yo f Augusta , Kennebe c County , particularl ybounde d and describe d a s follows : Beginnin g a t a l " iro n pip e found a t a n angl e poin t i n th e Northeasterl ysidelin e o f Easter n Avenu e (Bk-4089-p . 269) , a s show n o n a pla n entitled , "Standar d Boundar

ySurve

yfo r Centra l Main e Powe r Company , F . O'Conno r Superfun d Site " b

y Coffi n Engineering , Revisio n date d Marc h 22 , 1994 . Sai d poin t o f beginnin g i s als o situate d S 47"24'45 " E o f an d 52.7 8 fee € fro ma 3/4 " iron pip e foun d a t the mos t Southerlycorne r o f HenryR . & Lillia n W . Co x (Bk 1554-p . 126 ) . Thenc e N47 0 

### 42'O3 " E a distanc e o f 623.6 8 fee t t o a 5/8 " reba r se t i n a ston

e wal l i n the Southwesterl ylin e o f Lione l J . & Raymond A . Rodrigu e (B k 2857-p . 34) . Sai d reba r i s als o situate d S 60°26'23 " E o f an d 251.0 5 fee t fro

ma 5/8 " reba r set - i n a dril l hol e a t th e mos t Easterl ycorne r o f Donal d S . Rodrigu e (Bk 4164-p . 336 ) . Thenc e Southeasterl yalon g th e Southwesterl ylin e o f Ridrigue , an d partiall yfollowin g sai d stone wall , t o a 5/8 " reba r se t a t th e Northwesterl ysidelin e o f a 10 0 foo t wid e transmission lin e corrido r designate d Sectio n #1 9 (B k 1117-p . 314 ) . The ti e lin e betwee n th e two las t mentione d rebar s i s S 6O°46'07 " E and 1,354.7 2 feet . Thenc e S 35°12"18"" W alon g th e Northwesterl yline o f sai d transmissio n corridor , a distanc e o f 386.8 2 fee t t o a 5/8 " reba r set . Thenc e S 79°45 I 

### 02 " W along th e Northerl yline "_o f sai d transmissio n corridor , a distanc e o f 824.7 0 fee t t o a 5/8 " reba r se t i n th

e Northeasterl ysideline o f Easter n Avenue . Thenc e N40°50'03 " W along th e Northeasterl ysid e o f Eastern Avenue , a distanc e o f 822.3 1 fee t t o a 5/8 " reba r se t a t th e mos t Southerlycorne r o f lan d conveye d fro

mJean E . & Rober t L . Husse

yt o Centra l Main e Powe r Compan y(B k 3507-p . 195) . Thenc e continuin

g N40°50'03 " along th e Northeasterl ysid e o f Eastern Avenue , a distanc e o f 109.0 0 fee t bac k t o th e poin t o f beginning . Meanin g an

d intending t o describe 23.3 6 acre s o f land , a s show n o n a pla n "entitled , "Standard BoundarySurve yfo r

### Exceptin g th e ol d Fiel d buria l groun d whic h contain s abou t on e eight h o f an acre . 

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MEDE P COMMENTS , DATE D AUGUS T 9 , 2002 , O N TH E DRAF T FIVE-YEA R REVIE W REPORT

### 09/06/0 2 14:4 0 [ 3 :02/0 8 NO:88 2

S I AT E Ol : MAJN L DlPAltlMIN l ^1^ KlMVUtHNMC N I A l

ANGU S 3 KIN G Jf l MARTH A KIRKPATWC K

August 9

, 200 2 Terr yConnell y U S Environmenta l Protectio n Agency ME/VT/C T Superfun d SectionUSEP A 1 Congres s Stree

t Suit e 1 1 00 HB

T Boston , M A 0211 4 RE : Draf

t Fiv e Yea rReviewRepor

t O'Conne rJunkyar

d Superfun d Site Augusta , Main e Dea r Terry , Th e Main e Departmen t o f Environmenta l Protectio n (MEDEP ) has no wcomplete d its revie wo f th e documen t entitle d DRAFT Fiv e Yea rReviewRepor

t (Report ) fo rth e O'Conne rCompan ySit e (O'Conne rJunkyard Site , o rSite) , date d Jul y200 2 a s prepare d byTetr a Tec h NUS , Inc . fo rth e Environmenta l Protectio n Agenc y(USEPA) . MEDE P offer s th e followin g comments o n thi s Repor t Executiv e Summary : 1 . Sectio n 1 shoul d contai n a brie f summar

yof th e selecte d remedy , wit h emphasi s o n th e component

s of th e remed ytha

t involve d leavin g hazardou s substance s behin d an d subsequen t nee d fo ra 5 yea rreview . A s writte n i t appear s prematur e to read abou t th e soi l cove ran d th e Designate d Are a (I n Sectio n 3. 1 ) before an ydiscussio n of site operations , responses , o rremedie s ar e presented . 2 . Pag e E- 1 , Paragrap h 2 an d Paragrap h 3 : Her e an d throughou t th e Repor t mentio n i s mad e of institutiona l control s protectin g th e publi chealt h by preventin g exposure to groun d water , etc . Thi s i s incorrect . Th e Restrictive Covenan t i s currentl yhel d i n b yMEDE P i n escrow- i t has no t bee n Implemented , no rwas i t intended to b e unti l th e remedywas deeme d complete b ybot h MEDE P an d USEPA . 3 . Pag e E-2 , Firs

t Bulle t an d pag e E-4 , First Paragraph : That exposure pathway s ar e bein g controlle d ma

yb e a bi t misleadin g i n that th e restrictive covenants ar e 1 7 S-IATI " Hous n yfATior s nANiJin i POKILAN D I'HFKQU B is i r AtKMJSTA . MAIN F 04.HI . 1101 7 I0f . IIOC'A N «'1AI > » l I I'AN C O RI.IAI 1 iJUCENIRA l PKlVIJ . SKYWA Y PARK . (107 ) ln'1-lttm

IIANOOK . MAIN* . 04JH 1 PORILANO , MAIN P 0410 ) I'lM'SljU H ISIF , MAIN E 1147AV-10W 4 HA Y 11 1 PC. . llnSP M A l ST . UO7 > »<I-417| 1 PA X Ul>< ) «4M<H 4 I2O7 I fUj.r,«0 0 TA X llVTl Hlt-l'tOt

U07 ) 704-047 7 I-AX : (2H7 ) 764-HD 7 wr h file : vwo.iil.uv.mr.iii/iU p prln«t l o n rcrvcU J pape r

### 09/06/0 2 14:4 0 | 3 :03/0 8 NO:88 2

not Implemented yet an d a s of thi s writin g CM P ha s n o pla n i n place t o maintai n th e cove rove rth e Designate d Area . Repor t 1 . Pag e 1 - 2 state s tha t th e triggerin g action s fo rthi s 5 yea rrevie ware th e August 199 6 SCR Aan d th e Octobe r199 4 action s fo rOU- 2 an d OU-3 . Therefore , technically , th e 5 yea rrevie wi s overdue . Som e explanatio n fo rthi s i s needed fo r th e public recor

d - a t th e ver yleas t a n acknowledgemen t of thi s situatio n i s warranted . 2 . Pag e 2-1 , Tabl e 2-1 : Th e chronolog ypresente d i n Sectio n 2 shoul d includ e th e agreemen t betwee n DE P an d CM P since thi s agreemen t establishe d th e restrictive covenan t an d it s enforceabilitythat , once implemented , wil l provid e a measur e of contro l ove rth e exposure pathway s that th e Repor t keeps referrin g to as alread ybein g i n place . 3 . Pag e 3-1 , Sectio n 3.1. 1 • MEDE P doe s not understan d th e significance of identifyin g th e "smal l residence " tha t abut s th e Sit e alon g th e wester n boundary . Th e importan t thin g I s tha t lan d us e o n th e wester n sid e i s presentl yresidential . Th e actua l siz e of tha t particula rresidence i s irrelevant . 4 . Pag e Sectio n 3.1.3 , 4 l h sentence : Ther e i s a grammatica l erro r- replac e th e word "was " wit h th e wor d "were: " (i.e . Approximatel y24,00 0 cubi cyards... wer e imported.... " 5 . Pag e 3-3 , Sectio n 3.1.3 , Paragrap h 2 : Th e Repor t mention s TW

A I an d II I withou t an yprio rdefinitio n o rreferenc e to wha t th e acronym s mean . Thi s makes I t difficul t fo rth e reader . 6 . Pag e 3-3 , Sectio n 3.2 : Th e tex t state s tha t th e sit e i s not activel yused . Doe s thi s refe rt o CM P busines s activities , childre n playin g o n site , recreatio n vehicles , o rothe rsit e visitors ? Pleas e explai n what thi s mean s 7 . Tabl e 3-1 : Pleas e explai n furthe rth e apparen t changes i n cleanu p levels ; i n particula rth e chang e fo rPCBs i n Rigg s Broo k sediment

s fro m 1 pp m to 5

ppm . MEDE P i s no

t awar e o f thi s valu e havin g undergon e th e officia l proces s fo r chang e fro m th e 1 pp m a s originall yestablishe d i n th e ROD . Whe n wa s thi s change d propose d fo rpubli ccomment ? To MEDEP' s knowledg e neithe r regulator yagenc yofficiall yapprove d o f suc h a change . Rather , th e official , enforceabl e cleanu p leve l i s stil l 1 pp m whil e 5 pp m i s considere d a sor t of unofficia l trigge rleve l fo rremedia l action . 8 . Pag e 4-3 , Sectio n 4.2.1 , First Paragraph : Th e text state s that "Institutiona l control s limitin g acces s t o th e Sit e wer e include d i n th e for m o f a perimete rSit e fence. " A

t th e tim e o f th e ROD , th e regulator yagencie s incorrectl yreferre d t o fence s a s institutiona l controls . Pleas e updat e th e text . 9 . Figur

e 4-1 : Th e document woul d benefi t fro m a cleare rsit e sketc h tha n Figur e 4-1 . Sinc e th e TW AI I are a i s s o significan t i t shoul d b e clearl ydepicted . Also ,09/06/0 2 14:4 0 0 :04/0 8 N0:88 2

th e firs t 4 symbol s identifyin g th e variou s type s of monitorin g wells/location s ar e Identical . Acolo rversio n of thi s figure wher e th e firs t 4 symbol s are differentiate d byhu e woul d b e more helpful , o ri f th e figur e i s t o remai n blac k an d whit e the n contrastin g symbol s ar e necessary . 10 . Pag e 4-5 , Sectio n 4.2.2 : Th e text mention s th e establishmen t o f institutiona l controls , bu t fail s t o explai n o rspecifywha t the yare . Pleas e ad d a summary . 11 . Pag e 4-6 , Sectio n 4.2.3 , Firs t Paragraph : Th e text agai n incorrectl yrefer s to a 5 pp m cleanu p leve l fo rPCB s i n Rigg s Broo k sediments . Se e commen t # 7 an d correc t th e tex t here an d elsewhere i n th e Report . 12 . Pag e 6-3 , Sectio n 6.4.2 , Thir d Paragraph : Th e tex t Incorrectl ystate s that monitorin g wel l 106 B capture s a significan t portio n o f th e bedroc k groundwate r migratin g fro m th e site . Thi s i s not supporte d byan ydata , o reve n basi c hydrogeologica l principles . Wel l 106 B onl y"sees " groundwate rflowin g throug h its scree n - i t i n n o wa yactivel ycapture s adjacen t groundwater . A pressur e gradien t woul d hav e t o b e introduce d throug h th e wel l fo ri t t o d o what i s allege d here . Delete th e entir

e secon d sentence . 13 . Pag e 6-4 , Sectio n 6.4.3 , Result s Box : Sediment cleanu p leve l fo rPC B i s no t 5 pp m - i t i s 1 ppm . Se e commen t #7 . 14 . Pag e 6-5 , Sectio n 6.5 . Firs t Paragraph : Th e text incorrectl yrefer s to fence s an d wel l lock

s ar e institutiona l controls , whic h the yar e not . Further , i t claim s wel l lock s were no t necessar

yonc e th e vegetate d ca p wa s installed . Pleas e explai n howth e cove rnegate s th e nee d fo rsecurin g a monitorin g well . I n th e Interim , al l well s shoul d b e secure d wit h locks , especiall yconsiderin g th e following : Th e site i a Intentionall yno t secure d - i n fac t th e remova l o f th e fenc e wa s mad e into a medi a even t wit h regulator yan d CM P dignitarie s presen t - s o i t i s misleadin g t o repor t tha t trespassin g wa s no t observed . 15 . Pag e 6-5 , Sectio n 6.5 , Thir d Paragraph : Aresidenc e wa s recentl ybuilt adjacen t t o th e sit e o n th e eas t sid e acros s Rigg s Brook . Others ma yb e forthcoming . Therefore , claim s tha t n o developmen t of th e surroundin g are a are underwa yar e misleading . Also , th e institutiona l control s ar e onc e agai n mentione d i n th e tex t withou t an yexplanatio n a s t o what the yactuall yare . 16 . Pag e 7-1 , Sectio n 7.1.1 ; Th e text declare s that th e 1 2 inche s o f fil l woul d b e protectiv e eve n I f th e designate d are a was churne d u p an d th e clea n soi l an d PC B contaminate d soi l wer e mixe d (pag e 4-5 , First Paragraph) . However , th e text i n thi s sectio n the n refer s t o inspection s o f th e ca p t o chec k fo rerosio n an d placin g boundar

ymarkers t o identif

yth e edge s of th e Designate d Area . Thi s i s confusin g - th e repor

t shoul d clarif

ywhat EPA' s remedyi s wit h respec t to th e Designate d Area . Further , i t i s impossibl e t o verif yth e intergrit yo f th e soi l cove r i n th e absenc e of a marke rline rplace d underneat h withou t sampling . Lastly , ther e i s n o mentio n o

f MEDEP' s independen t agreement , independen t authority , an d enforceabl e requirement fo rmaintainin g th e 1 2 inche s o f clea n fil l ove rth e Designated Area .