SFUN D RECORD S CT R 

### 212511 2



## RECORD O F DECISIO N AMENDMEN T



## fo rth e SOL A OPTICA L USA , INC . SUPERFUN D SIT E

PETALUMA , CALIFORNI A

U.S . Environmenta l Protectio n Agenc y

Regio n I X Sa n Francisco , Californi a Marc h200 7

## ACRONYM S

ARAR s Applicabl e o r Relevan t an dAppropriat e Requirement s ICERCL A Comprehensiv e Environmenta l Response , Compensatio n an dLiabilit y Ac t DTS C Californi aDepartmen t o f Toxi c Substance s Contro l ' EP A ; Unite dState s Environmenta l Protectio n Agenc y GA C Granula r Activate dCarbo n IC s Institutiona l Control s MCL s Maximu mContaminan t Level s MN A Monitore dNatura l Attenuatio n

_____! NC PNationa l Oi l an dHazardou s Substance s Pollutio n Contingenc y Pla n NPDE S j Nationa l Pollutio n Discharg e Eliminatio n Syste m pp b Part s Pe r Billio n PRM D Sonom aCount y Permi t an dResourc e Managemen t Departmen t RCR A Resourc e Conservatio n an dRecover y Ac t Regiona l Boar d' ; Sa nFrancisc o Ba y Regiona l Wate r Qualit y Contro l Boar d

____ __i _„ __,„ - ___ RO D " ~~ " Recor do f Decisionlo r

Sol aOptica l USA , Inc . SuperfundTsTt e (1991 ) RO D Amendmen t

Recor do f

Decisio n Amendmen t Sol asit e o r

Sit e Sol aOptica l USA , Inc . Superfun dSit e T Ij Technica l Impracticabilit y VO C i Volatil e Organi c Compoun d[THI S PAG EINTENTIONALL Y LEF T BLANK ]

## PART 1 : TH E DECLARATIO N I . Sit e Nam e an d Locatio n Sol aOptica l USA , Inc . Superfun dSit e Petaluma , Sonom aCounty , Californi a EP A ID . No . CAD98117152 3 II . Statemen to f

Basi s an d Purpos e Thi s decisio ndocumen t

present s th e amende dremedia l actio nfo r th e Sol aOptica l USA , Inc . Superfun dSite (Sol asit e o r Site ) i n Petaluma , Sonom aCounty , California . Th e Unite dState s Environmenta l Protectio nAgenc y (EPA ) ha s chose nthi s actio ni n accordanc e wit hSectio n11 7 o f th e Comprehensiv e Environmenta l Response , Compensatio nan dLiabilit y Ac t (CERCLA) , a s amended , 4 2 U.S.C . § 9617 , an dth e Nationa l Oi l an dHazardou s Substance s Pollutio nContingenc y Pla n(NCP) , 4 0 CF R§ 300.435(c)(2)(ii) . Thi s decisio ni s base do n EPA' s Administrativ e Recor dfile . Th e lea dagenc y fo r

th e remedia l effor t

a t thi s Sit e i s th e EP A an dth e stat e suppor t agenc y i s th e Sa n Francisc o Bay Regiona l Water Qualit y Contro l Board(Regiona l Board) . Th e Regiona l Boar dha s informe dEP A tha t i t consider s th e Sit e t o b e alo w ris k an ddoe s no t

pla nt o hav e an y furthe r

involvemen t

wit hoverseein g remediation . III . Assessmen to f

Sit e Th e respons e actio nselecte di n th e 199 1 Recor do f Decisio n(ROD) , a s modifie db y thi s Recor do f Decisio nAmendmen t

(RO D Amendment) , i s necessar y t o protec t publi c healt h o r welfar e o r

th e environmen t

fro mactua l o r

threatene drelease s o f

hazardou s substances , pollutants , and/o r

contaminant s fro mthi s Sit e whic hma y presen t a nimminen t

an d substantia l endangermen t

t o publi c healt ho r

welfare . IV . Descriptio n o f

Selecte d Remed y Thi s RO D Amendmen t

modifie s th e previousl y selecte dremed y fo r th e Sol asite . A remedia l actio nwa s selecte dfo r th e Sol asit e i n 1991 . Th e origina l remedia l actio nwa s groundwate r

extractio nan dtreatment . Th e amende dremedia l actio ni s Monitore d Natura l Attenuatio n(MNA ) an dinstitutiona l controls , wit hmonitorin g o f both . Th e goa l fo r MN A i s aquife r

restoration . Th e institutiona l contro l wil l tak e tw o forms : a restrictiv e covenan t

an dCount y wel l permittin g restrictions . Th e restrictiv e covenan t wil l preven t

inappropriat e use s o f

th e groundwate r

tha t coul dresul t

i nunsafe exposure s t o humans . Sonom aCounty' s wel l permittin g authorit y wil l als o functio na s a n institutiona l contro l an dcontribut e t o th e overal l protectio no f huma nhealt han dth e environmen t

a t th e Sol asite . Sol aoperate dth e groundwate r extractio nan dtreatmen t

syste mfo r

approximatel y te n years , afte r

whic hi t cease dactiv e operation s an dmonitore dth e aquifer' s response . Th e respons e demonstrate dtha t natura l attenuatio nwa s reducin g contaminan t concentration sa t

rate s sufficien t

t o achiev e th e cleanu p standard s withi nareasonabl e timeframe . Sol a dismantle dth e groundwate r extractio nan dtreatmen t

syste mi n2002 . V . Statutor y Determination s Th e amende dremed y satisfie s th e requirement s o f CERCL A Sectio n12 1 an dth e NCP . Specifically , th e remed y i s protectiv e o f huma nhealt han dth e environment , complie s wit hal l Federal an dStat e requirement s tha t ar e applicabl e o r

relevan t an dappropriate , i s cost-effective , an dutilize s permanen t solution s t o th e maximu mexten t possible . Th e amende dremed y doe s no t includ e activ e treatmen t

a s aprincipa l elemen t

an d therefor e doe s no t

satisf y th e statutor y preferenc e fo r treatmen t a s aprincipa l elemen t

o f th e remedy . However , MN A wil l achiev e th e groundwate r cleanu p level s i nareasonabl e timefram e (les s tha n1 0 years ) an di nacost-effectiv e manne r an dfollow s severa l year s o f extractio nan dtreatment . I f th e cleanu p take s mor e tha nfiv e year s fro mth e previou s five-yea r revie w (complete d i n2005 ) t o achiev e cleanu p standards , asubsequen t five-yea r revie w wil l b e conducte dt o ensur e tha t

th e amende dremed y is , o r wil l be , protectiv e o f

huma nhealt han dth e environment . VI . Authorizin g Signature 

# A*-*A$ h \iXU^vv o MfriTC h36 ,iDat e Sit e Cleanu p Branc h

## PAR T 2 : TH E DECISIO N SUMMAR Y

I . Introductio n to th e Sit e an d Statemento f

Purpos e Th e Sol aOptica l USA , Inc . Superfun dSit e i s i n Petaluma , California , a t 150 0 Cade r Lane , jus t wes t o f th e intersectio no f

Lakevill e Highwa y an dInterstat e 101 . Fro m197 8 throug h2001 , Sol amanufacture deyeglas s lense s a t th e Site . Whe noperation s firs t began , Sol astore dvariou s manufacturing-relate dsolvent s i n undergroun dstorag e tank s a t th e Site . Afte r

discoverin g contaminatio ni n th e groundwate r nea r thos e tanks , Sol a remove dth e tank s an dha s bee nresponsibl e fo r cleanin g u p th e remainin g volatil e organi c compoun d(VOC ) contaminatio neve r since . Th e Sol asit e wa s liste do n th e Nationa l Prioritie s Lis t

o f Superfun dsite s i n Februar y 1990 . Th e groundwate r

aquife r a t th e Sit e i s th e sourc e o f

drinkin g wate r

fo r th e Cit y o f Petaluma . On e o f

th e City' s groundwate r

extractio nwell s wa s locate dnea r th e Sol asite , bu t i t wa s no t impacte db y th e Sit e contamination . However , th e wel l wa s shu t dow nt o avoi dinterferenc e wit hth e groundwate r clean-up . I n1991 , EP A decide dtha t Sola' s groundwate r

treatmen t syste mshoul db e expanded . Sol acomplie dan doperate dth e expande dsyste mfo r anothe r si x years . Eventually , however , th e syste mbecam e decreasingl y effective , an dSol astoppe doperatin g i t i n 1997 . Sinc e then , th e level s o f contaminatio ni n th e groundwate r hav e continue dt o decline , an dcontaminatio nabov e th e MC Lremain s i n onl y on e monitorin g well . EP A i s no w adoptin g adifferen t

approac ht o addres s th e clean-u p o f tha t smal l area . EP A selecte daremed y i n aRO D date dSeptembe r 27 , 1991 . Th e origina l RO D an dthi s RO D Amendmen t

were selecte di n accordanc e wit hSectio n11 7 o f CERCLA , 4 2 U.S.C . § 117 , an d4 0 C.F.R . § 300.435(c)(2)(ii ) o f th e NCP . EP A i s th e lea dagenc y responsibl e fo r directin g th e CERCL A remediatio nprocess ; th e Regiona l Boar di s th e suppor t agency . Th e Regiona l Boar dha s indicate dt o EP A tha t i t consider s th e Sit e alo w ris k an ddoe s no t

inten dt o provid e additiona l inpu t o nSit e work . Eventually , i t

becam e clear

tha t th e origina l remedy , agroundwate r extractio nan d treatmen t system , woul dno t

achiev e th e cleanu p standar do f 5 part s pe r

billio n(ppb ) fo r 1,1-DCA . Sola' s syste minitiall y reduce dcontaminan t concentrations , bu t

b y th e mid

1990 s thos e reduction s reache da n asymptot e wher e concentration s wer e essentiall y stayin g a t th e same , elevate dlevels , despit e continue doperatio no f th e system . Some part s o f th e contaminate daquife r

ha dachieve dth e cleanu p standar db y thi s time , bu t other s ha dnot . A t

tha t point , Sol astoppe doperatin g th e remedia l syste man dinstea d focuse do nmonitorin g th e aquife r an dit s contaminan t

characteristics . Subsequen t analysi s o f

th e monitorin g dat aestablishe dth e reliabilit y an deffectivenes s o f natura l attenuatio nprocesse s i nremediatin g th e smal l portio no f groundwate r

tha t wa s stil l slightl y contaminate dabov e th e clean-u p standard . I n additio nt o revisin g th e groundwate r remediatio napproach , thi s RO D Amendmen t document s EPA' s selectio no f arestrictiv e covenan t

a s anecessar y an dappropriat e institutiona l contro l a t

th e Site . Th e five-yea r

revie w conducte di n200 5 identifie dtha t n o institutiona l contro l wa s i nplac e (o r ha dbee nselecte di nth e origina l ROD ) t o preven t inappropriat e use s o f

th e groundwate r

an dsubsequen t

exposur e t o human s durin g th eclean-u p period . EP A conclude dtha t i t woul dnee dt o selec t

institutiona l control s i n a decisio n documen t

an dt o ensur e thei r

implementation , i n orde r

t o guarante e protectivenes s unti l th e clean-u p goal s ar e attained . Th e decision s documente di n thi s RO D Amendmen t ar e base do n th e Administrativ e Recor dfil e an dwil l becom e par t o f th e Administrativ e Recor dfil e i naccordanc e wit h4 0 C.F.R . § 300.825(a)(2 ) o f

th e NCP . A cop y o f th e Administrativ e Recor di s availabl e fo r revie w a t th e followin g locations : Petalum aPubli c Librar y 10 0 Fairground s Driv e EP A Superfun dRecord s Cente r Petalum aC A 9495 2 9 5 Hawthorn e St. , 4thFl . (707 ) 763-980 1 San Francisco , C A 9410 5 Hours : (415)536-2000 . 10a-9 p Tue s & We dHours : 8a-5 p Mo n - Fri 10a-6 p Mon , Thu , Fri , Sa t

### II . Site History , Contamination , an d Origina l Selecte d Remed y

Site Histor y an d Contaminatio n Sol aestablishe damanufacturin g facilit y a t 150 0 Cader Lane , Petaluma , California , jus t wes t o f th e intersectio n o f

Lakevill e Highwa y an dInterstat e 101 . The y manufacture d eyeglas s lense s a t

th e Sit e fro m197 8 t o 2001 . Th e facilit y ha don e manufacturin g buildin g an da nadjoinin g administratio n offic e building . Whe n Sol abega n operations , i t ha dsi x 1,000-gallo n undergroun dstorag e tank s behin dth e nort hcorne r o f th e manufacturin g building . Th e tank s were use dt o stor e solvent s suc ha s 1,1,1

- trichloroethan e (1,1,1-TCA) , aceton e andmethanol . I n1982 , Sol afoun dlo w concentration s o f VO C contaminatio n i n th e groundwate r beneat hit s property near

th e si x storag e tanks . Th e groundwate r aquife r wa s an dstil l i s th e Cit y o f

Petaluma' s drinkin g wate r source . Althoug hon e o f

th e City' s groundwate r extractio n well s wa s nea r

th e Sol aSite , i t

wa s no t impacte db y th e contamination . I n1983 , th e Regiona l Boar ddirecte dSol at o investigat e th e groundwate r contaminatio n a t th e Site . Sol aidentifie dth e followin g chemical s i n th e groundwater : 1,1

- dichloroethan e (1,1-DCA) , 1,1-dichloroethen e (1,1-DCE) , methylen e chloride , an d 1,1,1-TCA . Thes e chemical s appeare dt o hav e originate dfro mth e grave l surroundin g th e tan k an dadjacen t

soils . I n 1985 , Sol aremove dth e si x storag e tank s a s wel l a s th e surroundin g grave l an dsevera l fee t o f soi l fro mth e side s an dbotto mo f th e excavation . Furthe r investigatio n b y Sol areveale dth e exten t o f th e groundwate r

contamination . I n 1987 , th e Regiona l Boar dordere dSol at o construc t an doperat e agroundwate r extractio n an dtreatmen t

system . Th e treate dgroundwate r wa s discharge dint o Adob e Creek , jus t northwes t o f th e Site , unde r

apermi t fro mth e Regiona l Board . Th e extractio n an d treatmen t syste mbegan operatin g i n 1988 . Sol aals o arrange dt o hav e th e Cit y o f Petalum ashu t

dow n th e nearb y municipa l wate r suppl y well , t o avoi dinterferenc e wit h th e groundwate r

clean-u p effort s an dpreven t potentia l us e o f

Site-impacte dgroundwater . Pumpin g th e municipa l wel l coul dhav e graduall y draw n th e contaminate dgroundwate r cross-gradien t

toward s it , spreadin g th e contamination . I n1989 , EP A becam e th e lea dregulator y agenc y fo r remedia l activitie s a t

th e Site . O n Februar y 21 , 1990 , EP A adde dth e Sit e t o th e Nationa l Prioritie s Lis t o f Superfun dsites . Soo n thereafter , EP A issue da n administrativ e orde r directin g Sol at o conduc t

furthe r environmenta l samplin g an dt o prepar e aremedia l investigatio n repor t an dafeasibilit y stud y o f clean-u p options , bot ho f

whic hSol acomplete di n 1991 . Tha t year , EP A als o prepare da n assessmen t

o f risk s pose db y th e Sit e (describe dbelow) . Huma n Health Risk s I n1991 , EP A prepare daris k assessmen t

t o evaluat e th e huma n healt han denvironmenta l risk s pose db y contaminatio n a t th e Site . A ris k

assessmen t

begin s b y identifyin g th e chemica l contaminant s o f

concern . Th e assessmen t

the n evaluate s pathway s throug h whic hth e chemical s ca n trave l t o reac hhuma n o r ecologica l receptors . Th e huma n healt h evaluatio nthe n estimate s th e duratio n o f possibl e chemica l exposur e t o humans . (Th e ecologica l assessmen t

i s furthe r describe di n th e subsequen t sectio n entitle d"Ecologica l Ris k Evaluation") . Al l o f

thi s informatio n i s use dt o calculat e ahuma n healt hrisk . Thi s ris k i s presente di ntw o parts : th e carcinogeni c effect s (cancer-causin g effects) , an dth enon-carcinogeni c effect s (al l othe r healt heffects) . Th e carcinogeni c effec t i s expresse di n term s o f a n additiona l chanc e o f

contractin g cancer , abov e th e norma l rate , a s aresul t o f th e chemica l exposure . Th e non-carcinogeni c effec t i s show na s ahazar dquotient ; value s greate r tha n1 indicat e tha t

a neffec t o nhuma nhealt hwil l occu r (suc ha s impact s t o centra l nervou s syste mo r

specifi c organs) , an dles s tha n1 indicate s that n o effec t wil l occur . Th e 199 1 ris k

assessmen t

identifie d1 2 volatil e organi c compound s (VOCs ) a s chemical s o f concern : acetone , butanone , 1,1-dichloroethane , 1,2-dichloroethane , 1,1

- dichloroethene , freo n113 , 4-methyl-2-pentanone , tetrachloroethene , toluene , 1,1,1

- trichloroethane , 1,1,2-trichloroethane , an dtrichloroethene . VOC s ar e extremel y volatile , meanin g the y vaporiz e easil y an dthu s constantl y mov e fro mon e mediu mt o another , fo r exampl e fro msoi l t o wate r o r air . Th e ris k

assessmen t

establishe dtha t

th e mai nexposur e pathwa y fo r

human s wa s throug hthei r homes . Thi s potentia l exposur e wa s base do na hypothetica l futur e residentia l use . However , th e Sit e wa s an dstil l i s use dfo r ligh t industrial/commercia l purposes . Residentia l use s ar e no t planne dfo r

th e Site . Th e existin g groundwate r

plum e doe s no t

exten dbelo w an y residences , an dn o drinkin g wate r well s operat e near

th e plume . Th e Sit e an dth e surroundin g propertie s receiv e wate r fro m th e Cit y o f

Petaluma' s municipa l wate r supply , whic hi s no t

impacte db y th e Site . I f resident s wer e t o us e th e contaminate dgroundwate r fo r drinkin g o r

washin g the y coul d inges t th e contaminant s o r

absorb the mthroug hthei r skin . Wate r

fro mafauce t

o r showerhea dcoul dreleas e contaminant s tha t resident s coul dinhale . Th e chemical s coul d als o mov e int o indoo r

ai r fro mth e groundwate r

an dsoi l beneat hhome s vi a"vapo r intrusion. " Th e ris k assessmen t

calculate dtha t

aperso nlivin g i n ahous e directl y abov e th e contaminatio nwh o wa s expose dt o th e vapo r intrusio nal l o f

his/he r life woul dhav e a n exces s cance r

ris k o f 9 i n 1,000,00 0 (9xlO~ 6 ) . Th e nationa l averag e rat e o f cance r fro mal l cause s i s 1 i n 4 . Th e calculate d"excess " cance r ris k mean s tha t

i f amillio npeopl e wer e expose dt o thi s amoun t

o f contaminatio nfo r

thei r lifetimes , ther e migh t

b e nin e additiona l case s o f

cancer . Th e assessmen t

conclude dtha t

ther e woul dno t

b e an y non carcinogeni c healt heffects . Th e ris k assessmen t

als o calculate dtha t

aperso nwh o use dth e contaminate dgroundwate r fo r residentia l wate r

suppl y al l o f

his/he r life woul dhav e a nadditiona l 1 i n10,00 0 (IxlO" 4 ) ris k

o f contractin g cancer . Th e ris k assessmen t

conclude dtha t

ther e woul dno t

b e an y non-carcinogeni c healtheffects . Subsequen tRis kEvaluatio n Additiona l ris k

evaluation s wer e conducte di n 200 5 a s par t o f th e five-yea r

review . EP A performe dascreenin g leve l evaluatio no f th e potentia l fo r

remainin g level s o f contaminant s t o caus e negativ e healt heffect s eithe r b y enterin g commercia l building s vi a vapo r intrusio no r

throug hhuma n ingestio no f home-grow nproduce . T o evaluat e th e potentia l ris k o f vapo r intrusion , EP A compare dth e curren t groundwate r contaminan t

concentration s t o it s publishe d"Target Groundwate r

Concentrations " an d

1 "Draf t Guidanc e fo r

Evaluatin g th e Vapo r

Intrusio n t o Indoo r

Ai r Pathwa y fro mGroundwate r an d Soils, " EP A OSWER , Novembe r 2002 , Do c No . EPA530-D-02-004 .th e Regiona l Board' s publishe d"Groundwate r Screenin g Level s fo r

Evaluatio n o f Potentia l Vapo r

Intrusio n Concerns." 2 Al l curren t contaminan t

concentration s i n th e groundwate r

wer e foun dt o b e wel l belo w bot hth e vapo r intrusio n targe t

an dscreenin g levels . O n thi s basis , EP A determine dthat vapo r intrusio n doe s no t

pos e ahuma n health ris k a t thi s Site . T o evaluat e th e potentia l effect s o n garden s an dhomegrow n fruit s an dvegetables , EP A examine dothe r

existin g studie s o n th e subject . Researc hdemonstrate s tha t volatil e chemical s d o no t

buil du p i n th e plan t

tissue s eve n i f

contaminate dgroundwate r beneat ha garde n manage s t o reac hth e plant s an dth e chemical s ar e absorbe db y th e plants . Whe n volatil e chemical s mov e int o plan t leaves , the y ar e release dthroug hth e tin y opening s i n th e plan t leave s wher e ga s exchang e occur s an dtherefor e d o no t accumulate . Studie s hav e als o show n tha t

volatil e chemical s take n u p throug hplan t root s ten dt o concentrat e i nth e cell s near

th e surfac e o f

th e roots . Fo r

roo t vegetable s suc ha s beets , carrot s an d potatoes , thes e cell s ar e typicall y los t durin g washin g an dpeelin g o f th e produce . Plant s ar e als o abl e t o brea

k dow n o r degrad e volatil e chemicals . Thus , an y suc hchemical s take n u p b y th e plant s ma y b e presen t temporaril y i n th e root s an dstem s o f th e plan t bu t ar e muc hles s likel y t o b e presen t i n th e leave s o r

othe r above-groun dpart s o f

th e plant . I nsummary , existin g studie s indicate dtha t uptak e an daccumulatio n o f volatil e chemical s i nplants , an dsubsequen t

exposur e fro mhuma n consumption , woul db e minimal . Ecologica l Ris k A s par t o f th e 199 1 ris k

assessment , EP A als o prepare da n ecologica l ris k assessmen t

t o evaluat e possibl e impact s t o th e environment . Th e ecologica l assessmen t focuse do n possibl e impact s o n nearb y Adob e Creek . Thi s cree k i s th e closes t

surfac e wate r

bod y t o th e Site . A t

th e tim e o f

th e assessment , aloca l environmenta l grou p ha dlaunche da projec t t o reintroduc e anadromou s steelhea dtrou t t o th e creek . EP A examine ddat afro mgroundwate r monitorin g well s betwee n th e Sol afacilit y an d Adob e Creek . Base do n thi s data , EP A determine dtha t n o contaminant s wer e movin g toward s o r

ha dreache dth e creek . Th e assessmen t di ddetermin e tha t

i f th e groundwate r extractio n syste mwer e no t operating , contaminate dgroundwate r fro mth e Sol afacilit y coul dflo w i n th e directio n o f Adob e Creek . However , th e contaminan t concentration s i n th e groundwate r

beneathth e Sol afacilit y were belo w federal surfac e wate r qualit y criteri afo r

th e protectio n o f

aquati c life a t

th e tim e th e treatmen t

syste mwa s shu t

off . Today , th e Sit e environmenta l settin g i s no t muc hdifferen t

tha n i t wa s i n 1991 . Th e on e are ai n th e aquife r

tha t ha s no t ye t attaine dth e groundwate r clean-u p standar di s locate d o n aparce l adjacen t

t o th e origina l facilit y property . Thi s parce l i s currentl y a n ope n fiel d i nth e proces s o f

bein g develope dfo r

ligh t industrial/commercia l use . Approximatel y one-thir do f

tha t propert y ha s bee n recentl y graded . Th e fiel dha s no t otherwis e change d sinc e th e tim e o f

th e origina l ris k

assessment . N o ne w ecologica l receptor s wer e foun da t th e Site .

"Screenin g Fo r

Environmenta l Concern s a t Site s Wit hContaminate dSoi l an dGroundwater , " Regiona l Board , Februar y 2005 .Origina l Selecte d Remed y

Base do n th e remedia l investigatio n report , feasibilit y study , an dris k assessment , EP A issue dth e origina l RO D o n Septembe r 27 , 1991 . Th e RO D determine dtha t a n expande d groundwate r

extractio n an dtreatmen t

syste mwa s th e mos t

appropriat e metho dfo r remediatin g contaminatio n a t th e Site . Th e RO D specifie dth e following : This remedy addresses groundwater at the site and

consists of:

• groundwater

monitoring to assure capture of contaminated

groundwater

and to demonstrate restoration of groundwater

to cleanup standards throughout the aquifer,

• operation of

existing extraction wells (8),

• construction and

operation of

two (2) additional

shallow extraction wells,

• conversion of

monitoring wells lf-13 and If-17 to deep extraction wells,

• construction and

operation of

additional

piping for

the new and

converted

wells,

• on-site treatment

and discharge off-site or

discharge to the City ofPetaluma sewage treatment

system. The intent of this remedy is to restore groundwater to its beneficial

use, whichfor

this site is drinking water. Based on information obtained

during the remedial

investigation and on a careful

analysis of

all remedial alternatives, EPA and

the State of

California believe that

the selected

remedy will

achieve this objective. The selected

remedy includes groundwater extraction for

an estimated

period of 15to 20 years. This groundwater

extraction system will

operate until

the cleanup standards are achieved and continuously maintained

throughout

the aquifer. The cleanup standards are state or federally promulgated

drinking water

standards. Until

these standards are achieved and continuously maintained, EPA will periodically re-evaluate the remedy every five years with the first evaluation in October

1993. At these evaluations, if available EPA methodology is more accurate, the risks of' soil/groundwater

gases migrating through the soil into potential

residences on the site will be re-evaluated. It may become apparent, during implementation or operation of

the groundwater extraction system, that

contaminant

levels have ceased

to decline and

are remaining constant at levels higher

than the cleanup standards. Based on the performance data, operation of

the extraction system will be adjusted

as warranted

if so determined

during the periodic EPA evaluations. For example, it

may be appropriate to discontinue operation of

extraction wells in areas where cleanup goals have been attained, alternate pumping at

-wells to eliminate stagnation points, and pulse pump to allow aquifer equilibration and

encourage adsorbed

contaminants to partition into groundwater for extraction.

### III . Basi s fo rth e Documen t

Thi s sectio n describe s th e informatio n regardin g tw o issue s tha t prompte dan dno w suppor t th e fundamenta l remed y chang e describe di n thi s RO D Amendment : (1 ) groundwate r

clean-up , an d(2 ) institutiona l controls . Groundwate rClean-u p Sol abega n operatin g th e groundwate r extractio n an dtreatmen t

syste mi n 1987 , a s require db y th e Regiona l Board . Sol aexpande dth e syste mi n 199 2 pursuan t t o EPA' s ROD , an dcontinue doperations . Th e syste mwa s expecte dt o restor e th e shallo w groundwate r

t o clean-u p standard s withi n15-20 years . Initially , concentration s o f th e VO C contaminatio n a t

th e Sit e decrease dsignificantly . B y 1997 , however , th e rat e o f contaminan t

reductio n slowe dt o almost zero . Groundwate r

monitorin g dat aa t

fou r well s showe dtha t

concentration s o f

tw o contaminants , 1,1-DC Ean d1,1,-DCA , appeare dt o hav e stabilize dan dreache da n asymptot e a t level s abov e th e clean-u p standards . Continue dmonitorin g reflecte dn o furthe r reduction s i ncontaminan t concentrations . Some part s o f

th e contaminate daquife r

ha dachieve dth e clean-u p standar do f 5 pp b (fo r 1,1-DCA ) b y thi s time , bu t som e part s ha dnot . Th e extractio n an dtreatmen t syste mwa s n o longe r effectivel y removin g thes e lowe r concentration s o f

contaminant s fro mth e groundwater . I n1997 , Sol arequeste dapprova l fro mEP A t o shu t of f th e extractio n an dtreatmen t syste man dissu e atechnica l impracticabilit y (TI ) waiver , arguin g tha t th e clean-u p goal s fo r thes e tw o contaminant s coul dno t b e achieve dusin g extractio n an dtreatment . EP A requeste dinstea dtha t

Sol aexamin e MN A a s apotentia l remed y fo r th e Site . Sol acease d operatin g th e groundwate r extractio n an dtreatmen t

syste man dmonitore dth e aquifer' s response. 3 Th e concentration s o f

th e tw o remainin g contaminant s slowl y declined . I n 2001 , Sol a analyze dth e dat agathere dsinc e syste mshut-dow n i n 199 7 an dpresente dit s evaluatio n o f MNA , followin g EP A guidance. 4 Sol aconclude dtha t extractio n an dtreatmen t

alon e woul dno t b e capabl e o f

achievin g th e clean-u p standar dfo r th e remainin g aquife r contaminant . Sola' s evaluatio n conclude dtha t MN A woul dlikel y b e a n effectiv e remed y fo r attainin g th e clean-u p standard . Th e extractio n an dtreatmen t syste mwa s decommissione di n 2002. 5 Sinc e 2002 , monitorin g ha s show n tha t concentration s o f

th e tw o contaminant s hav e continue dt o decline . Concentration s o f 1,1-DCE droppe dbelo w th e clean-u p standar do f 6 pp b i n al l well s i n 200 4 an dha s consistentl y remaine dbelo w th e standar dsince. 6 Concentration s o f

1,1-DC A decline da s well . Th e contaminan t i s no w detectabl e a t

onl y on e singl e on-sit e well , W-27 , wher e it s leve l ha s droppe dt o 1 2 pp b (a s o f Decembe r 2006) , slightl y abov e th e clean-u p standar do f 5 ppb . Al l othe r

on-sit e well s sho w 1,1

-

3 Lette r t o Clair e McCarthy , Sol aOptical , fro mHoll y Hadlock , EPA , Januar y 10 , 1997 . 4 "Evaluatio n o f

Monitore dNatura l Attenuatio n a s aRemed y t o Mee t Remedia l Actio n Objectives , Sol a Optica l USA , Inc. , Site , Petalum aCalifornia, " LF RLevin e Fricke , Apri l 4 , 2001 . 5 Lette r t o Roma n Starno , Sol aOptica l USA , Inc. , fro mHoll y Hadlock , EPA , Novembe r 5 , 2001 . 6 "Secon dFive-Year

Revie w Repor t

fo r th e Sol aOptical US A Inc . Superfun dSite, " EPA , Septembe r 2005 .DC A concentration s belo w th e clean-u p standard . Th e highe r leve l o f contaminatio n i n W-2 7 i s likel y du e t o th e well' s location : W-2 7 i s directl y downgradien t fro mth e locatio n o f

th e origina l contaminan t

release , an dth e las t

o f th e contaminant s hav e slowl y bee n release dfro mth e soil s an dflowe ddow n t o W-27 . A s aresul t

o f th e finding s o f

th e groundwate r

monitorin g an devaluation , EP A i s amendin g th e RO D t o selec t MN A a s th e remed y fo r

accomplishin g th e groundwate r clean-u p standards . Institutiona l Control s Th e secon dissu e addresse db y thi s RO D Amendmen t i s th e nee dfo r

institutiona l controls . Institutiona l control s (ICs ) ar e non-engineering , lega l measure s tha t hel p preven t o r limi t th e potentia l fo r

exposur e t o hazardou s substance s b y restrictin g lan do r wate r use . On e commo n institutiona l contro l i s arestrictiv e covenan t whic hi s a n agreement , recorde dwit hth e count y recorder' s office , whereb y alan downe r agree s t o restric t th e us e o f

hi s o r he r property . EP A firs t identifie dth e nee dfo r

institutiona l control s i n it s 199 1 healt hris k assessment. 7 Th e assessmen t

recommende dtha t

institutiona l control s b e implemente da t th e Sit e t o preven t an y us e o f

th e contaminate dgroundwate r fo r drinkin g wate r

supplie s befor e drinkin g wate r

standard s ar e achieved . Th e remed y selecte di n th e 199 1 ROD , however , di dno t includ e institutiona l controls . Th e secon dSit e five-yea r review , conducte di n 2005 , agai n raise dth e nee dfo r institutiona l control s a t

th e Site . Th e revie w foun dtha t n o control s were i n plac e (o r ha d bee n selecte di n th e origina l ROD ) tha t woul dpreven t

inappropriat e use s o f

th e groundwater , creatin g aris k o f unsaf e exposure s t o human s durin g th e clean-u p period . Therefore , th e five-yea r

revie w recommende dtha t institutiona l control s b e selecte di n a decisio n documen t

an dimplemente dt o guarante e protectivenes s durin g th e interi mclean

u p perio dunti l th e clean-u p standard s ar e attained . I n respons e t o thi s recommendation , EP A ha s identifie da n appropriat e institutiona l contro l mechanism , arestrictiv e covenant , t o b e include di n thi s RO D Amendmen t an d discusse di n mor e detai l below .

7 "Publi c Healt

hRis k Assessment , Sol aOptica l USA , Inc . Site , " CH2 M Hill , Apri l 1991 . 8 "Secon dFive-Yea r

Revie w Repor t

fo r th e Sol aOptical US A Inc . Superfun dSite , " EPA , Septembe r 2005 . 1 0

### IV . Descriptio n o f Curren tAlternative s Origina l Selecte d Remed y Th e 199 1 RO D selecte datreatmen t remed y t o restor e contaminate dgroundwate r t o it s beneficia l us e (drinkin g water) . Th e origina l remed y di dno t includ e an y containmen t component s o r

institutiona l controls . Th e selecte dremed y require dgroundwate r extractio nan dtreatmen t

syste munti l th e clean-u p standard s wer e achieve dan dcontinuousl y maintaine dthroughou t th e affecte d portion s o f

th e aquifer . Dependin g o n th e particula r contaminant , th e standard s wer e se t a t eithe r th e stat e o r

federall y promulgate ddrinkin g wate r standard s ( 5 pp b fo r

1,1-DCA) . Th e RO D estimate dtha t

th e remed y woul dnee dt o operat e fo r 1 5 t o 2 0 year s t o attai nth e clean-u p standards . Th e majo r Applicabl e o r

Relevan t an dAppropriat e Requirement s (ARARs ) associate d wit hth e origina l remed y consiste do f federal an dStat e o f

Californi alaw s an dregulation s establishin g drinkin g wate r standard s an drequirement s fo r soli dan dhazardou s wast e handlin g an ddisposal , hazardou s wast e contro l laws , a s wel l a s municipa l o r count y hazardou s materia l ordinances . Thes e requirement s ar e describe dbelow . EP A determine dtha t

bot hth e federa l an dStat e o f Californi adrinkin g wate r standards , whicheve r wa s mos t stringen t fo r eac hchemica l o f

concern , wer e ARAR s fo r th e Sit e groundwater . Se e th e followin g tabl e fo r details . 199 0 Maximu m Drinkin g Wate rCleanu p Concentratio n (ppb ) Standard s (ppb ) Standard s chemica l Shallo w Dee p Stat e Federa l (PP b ) 1,1-DC E 1,1-DC A 1,1,1-TC A Freo n 11 3 1,40 0 28 0 22 0 9 2 2

1 1 0 2 6

5 20 0 1,20 0 7

- - 20 0

- - 6

5 20 0 1,20 0 Th e groundwate r

extractio nan dtreatmen t

syste muse dgranula r

activate dcarbo n(GAC ) adsorptio nfo r

VO C removal . GA C us e trigger s requirement s fo r th e regeneratio no r disposa l o f

th e spen t GAC . I f th e spen t GA C wer e a"listed " o r

"characteristic " waste , i t woul db e regulate da s ahazardou s wast e unde r th e federa l Resourc e Conservatio nan d Recover y Ac t

(RCRA ) an dCalifornia' s hazardou s wast e contro l laws. 9 On-sit e storag e o f contaminate dGA C ma y als o trigge r substantiv e requirement s unde r stat e laws 1 0 an d municipa l o r

count y hazardou s materia l ordinances , includin g constructio nan d monitorin g requirement s fo r storag e facilities . Ne w Remed y Th e ne w remed y utilize s th e following : • Monitore dNatura l Attenuatio nt o achiev e groundwate r clean-u p standards ;

9 Californi aHealt h& Safet y Cod e §§25100 , etseq. ; Californi aCod e o f Regulations , ti t

22 , §§67520

- 67525 . 1 0 Californi aCod e o f

Regulations , ti t

2 2 §§67180-6719 4 an d§§67240-67248 .

1 1• Institutiona l Control s t o protec t agains t inappropriat e us e o f

th e contaminate d groundwate r

unti l th e clean-u p standard s ar e achieved ; an d

• Monitorin g o f

bot ho f th e remed y component s unti l clean-u p standard s ar e achieve dan dsustained . Th e ter m"Monitore dNatura l Attenuation, " a s use db y EP A i n Directiv e Numbe r 9200.4

- 17P , refer s t o th e relianc e o n natura l attenuatio nprocesse s (withi nth e contex t o f a carefull y controlle dan dmonitore dsit e cleanu p approach ) t o achiev e site-specifi c objective s withi natim e fram e tha t i s reasonabl e compare dt o tha t offere db y othe r

mor e activ e methods . Th e natura l attenuatio nprocesse s tha t ar e a t wor k i nsuc haremediatio n approac hinclud e avariet y o f physical , chemical , o r

biologica l processe s that , unde r favorabl e conditions , ac t

withou t huma ninterventio nt o reduc e th e mass , toxicity , mobility , volume , o r

concentratio no f

contaminant s i n soi l o r

groundwater. 1 1 Th e followin g natura l attenuatio nmechanism s ma y b e activ e a t th e Site : dilution , dispersion , diffusion , volatilization , sorption , biodegradation , an dabioti c degradation . Al l o f thes e processe s resul t

i n adecreas e i n th e dissolved-phas e concentratio no f th e contaminant . However , onl y biodegradatio nan dabioti c destructio nresul t i ndestructio no f

th e contaminant . MN A wil l b e utilize dunti l th e clean-u p standard s ar e achieve dan dcontinuousl y maintaine dthroughou t

th e aquifer . Th e standard s ar e th e stat e o r federall y promulgate d drinkin g wate r

standard , whicheve r

i s mor e stringent , i n thi s cas e th e stat e standard . Thi s remed y wil l achiev e th e clean-u p standar dwithi na n estimate don e t o thre e years . Th e MN A mus t

b e monitored , pursuan t

t o a n EPA-approve dmonitorin g plan , an dth e dat a an danalysi s reporte dt o EPA . Th e secon dcomponen t

o f th e remed y i s th e implementatio no f institutiona l controls . A s note dabove , IC s ar e non-engineering , lega l measure s tha t limi t th e potentia l fo r

exposur e t o hazardou s substance s b y restrictin g lan do r wate r use . Thes e control s ca n consis t o f governmenta l controls , proprietar y controls , enforcemen t tools , o r informationa l controls . Governmenta l control s ar e usuall y implemente dan denforce db y astat e o r loca l governmen t

an dar e use dt o restric t

propert y o r

resourc e use ; example s includ e zoning , wel l drillin g o r

wate r usag e restrictions , licensing , an dpermitting . Proprietary control s ar e lega l instrument s place di nth e chai no f titl e t o rea l propert y tha t

conve y apropert y interes t fo r purpose s o f

imposin g restriction s o n lan do r wate r use . A commo n proprietar y contro l i nCaliforni ai s arestrictiv e covenan t whic hi s a nagreement , recorde d wit hth e count y recorder' s office , whereb y alan downe r agree s t o restric t

th e us e o f

hi s o r he r property . Th e Stat e o f

Californi aha s promulgate daspecifi c statut e authorizin g an d establishin g requirement s fo r suc hcovenant s (discusse dfurthe r i n ARAR s discussio n below) . Enforcemen t

tools fo r 1 C component s includ e enforceabl e order s an dconsen t decrees , whic hEP A ca n us e t o compe l apart y t o limi t certai nsit e activitie s an dt o ensur e th e performanc e o f

affirmativ e obligations . Informationa l control s provid e potentia l user s o f

1 1 "Us e o f Monitore dNatura l Attenuatio na t Superfund , RCR A Correctiv e Action , an dUndergroun d Storag e Tan k

Sites, " Offic e o f

Soli dWast e an dEmergenc y Response , Directiv e Numbe r 9200.4-17P , U.S . Environmenta l Protectio n Agency , Apri l 1999 . 1 2lan do r

wate r informatio nabou t

th e presenc e o f

hazardou s substance s an dofte nwar n agains t takin g specifi c actions , bu t thes e control s (includin g Stat e registries , dee dnotices , an dadvisories ) ar e no t

enforceable . Th e primar y institutiona l contro l fo r thi s Sit e wil l b e arestrictiv e covenant . A restrictiv e covenant , als o know na s adee drestriction , i s atyp e o f proprietar y contro l tha t

i s signe d b y th e propert y owne r

and , typically , th e Stat e o f California , an dtha t

include s EP A a s a third-part y beneficiar y wit hright s t o enforce . Th e restrictiv e covenan t a t th e Sol asit e wil l restric t

th e us e o f

groundwate r

contaminate dabov e th e clean-u p level . Th e objectiv e o f th e restrictio ni s t o preven t use s o f th e groundwate r

tha t coul dresul t

i nunacceptabl e exposur e o f

human s o r

th e environmen t

t o contaminants . Th e restrictiv e covenan t mus t remai ni nplac e unti l th e groundwate r clean-u p standar di s me t

an dmaintaine dfo r

a t leas t tw o year s throughou t

th e Site . Th e loca l wel l permittin g proces s provide s a n additiona l laye r o f institutiona l contro l tha t wil l hel p preven t

huma nexposur e t o contaminate dgroundwate r a t th e Sol asite . Th e Sonom aCount y Permi t

an dResourc e Managemen t Departmen t

(PRMD ) i s responsibl e fo r issuin g al l wel l installatio npermit s i nth e county . PRM D ha s asyste mcalle dPermi t Plu s tha t i s use dt o maintai ninformatio nabou t properties . A t

EPA' s request , PRM D place danot e i n th e Permi t Plu s syste mregardin g th e Sit e parce l tha t lie s directl y abov e th e contaminate dgroundwater . Th e not e state s tha t th e parce l i s par t

o f aSuperfun dsit e an dtha t wel l permit s shoul dno t

b e issuedbefor e consultin g wit hPRM D an dU.S . EPA . Accordin g t o PRMD , i f

anyon e request s apermi t

fo r th e Sol asit e parcel , PRM D wil l se e tha t notation . Th e institutiona l control s mus t als o b e monitored , pursuan t t o a n EPA-approve d monitorin g plan , an dth e result s reporte dt o EPA . Th e primar y ARAR s associate dwit hth e ne w remed y consis t o f federal 1 2 an dStat e o f California 1 drinkin g wate r standard s an dth e stat e regulation s regardin g environmenta l restrictiv e covenants. 1 4 Th e federa l an dStat e o f Californi adrinkin g wate r standard s wer e describe di n th e "Origina l Selecte dRemedy " sectio nabove . Thei r applicatio nt o th e ne w remed y i s th e sam e a s fo r

th e origina l remedy . Th e stat e regulation s regardin g environmenta l restriction s ar e Californi aCivi l Cod e Sectio n147 1 (a ) an dTitl e 2 2 o f th e Californi aCod e o f

Regulations , Sectio n67391 . l(a)(l) , (a)(2) , an d(d) . Sectio n147 1 specifie s ho w environmenta l covenant s ar e t o b e recorde dan dmad e applicabl e t o successors . Th e substantiv e provisio no f Sectio n147 1 - subpar t

(a ) - i s a n ARA Rfo r thi s RO D Amendmen t

becaus e complianc e wit hthi s sectio ni s necessar y fo r th e restriction s t o ru n wit hth e land . Th e substantiv e provision s o f Sectio n67391. 1 - (a)(l) , (a)(2) , an d(d ) - ar e als o ARAR s fo r thi s RO D Amendment . Thes e regulation s includ e requirement s fo r

imposin g covenan t

restriction s an dfo r

properl y recordin g th e covenant .

1 2 Saf e Drinkin g Wate r

Ac t (SDWA) , Sectio n 1412,4 2 US C §300g-l ; Nationa l Primar y Drinkin g Wate r Regulations , 4 0 CF RPar t 141 . 1 3 Californi aSaf

e Drinkin g Wa i Domesti c Wate r

Qualit y Monitorin g Regulations , Californi aCod e o f Regulations , tit . 22 , div . 4 , ch . 15 . 1 4 Californi aC i (a)(2) , an d(d) . 1 3 Californi aSaf

e Drinkin g Wate r

Act , Californi aHealt h& Safet y Cod e §§116270-116751 ; Californi a ) 1 4 Californi aCivi l Cod e sectio n §1471(a) ; an dCaliforni aCod e o f Regulations , ti t

22 , §67391. 1 (a)(l) , 1 3Remedia l Actio n Objective s

Th e RO D Amendmen t

wil l no t affec t th e Remedia l Actio n Objective s state di n th e origina l ROD . Thos e objective s ar e t o restor e groundwate r t o it s beneficia l use , whic hi s drinkin g water . Fo r

th e remainin g contaminan t o f concern , 1,1-DCA , th e cleanu p standar di s th e stat e promulgate ddrinkin g wate r standar do f

5 ppb . Expected Outcomes Th e expectedoutcom e o f

thi s RO D Amendmen t

i s th e sam e a s th e expecte doutcom e o f th e 199 1 ROD : th e contaminate dgroundwate r wil l b e restore dt o it s beneficia l us e a s municipa l supply . Thi s RO D Amendmen t contemplate s n o change s t o lan dus e o r cleanu p levels .

1 4

### V . Evaluatio n o f Alternative s Th e purpos e o f

thi s evaluatio ni s t o compar e th e thre e remedia l actio nalternative s identifie dusin g th e "nin e criteria " establishe di n th e Nationa l Contingenc y Plan , 4 0 CF R § 300.430(e)(9) . Th e resultin g strength s an dweaknesse s o f th e alternative s ar e the n weighe dt o identify th e alternativ e providin g th e bes t balanc e amon g th e nin e criteria . Th e criteri aare : (1 ) overal l protectio no f

huma nhealt han dth e environment ; (2 ) complianc e wit happlicabl e o r relevan t an dappropriat e requirement s (ARARs) ; (3 ) reductio no f

toxicity , mobility , o r

volum e throug htreatment ; (4 ) long-ter meffectivenes s an dpermanence ; (5 ) short-termeffectiveness ; (6 ) implementability ; (7 ) cost ; (8 ) stat e acceptance ; an d (9 ) communit y acceptance . RA#1 : N o Actio n RA# 1 i s th e "N o Action " alternative , require db y th e NCP . Thi s evaluatio nestablishe s a baselin e agains t

whic ht o compar e th e othe r alternatives . Th e N o Actio nalternativ e consist s o f

n o furthe r actio nt o clea nu p contaminate dgroundwate r a t thi s Site . Th e existin g contaminatio nwoul dremai ni nth e groundwate r a t it s curren t

concentrations , unti l i t naturall y degrade s ove r

time . Currently , on e chemica l o f concern , 1,1

- dichloroethen e (1,1-DCA ) exist s i n th e groundwate r a t concentration s exceedin g it s 5 pp b clean-u p goal . N o groundwate r monitorin g o r

institutiona l control s woul db e implemented . RA#2 : Extractio n an d Treatment , Institutiona l Control s RA# 2 consist s o f

groundwate r

extraction , treatment , an doff-sit e disposa l o f treate d effluent , an dinstitutiona l controls . Thi s alternativ e resemble s th e remedia l actio n selecte di n th e 199 1 ROD , wit hth e additio no f institutiona l controls . Th e 199 1 RO D selecte dgroundwate r

extraction , on-sit e treatmen t wit hGA C adsorption , an doff-sit e discharg e t o nearb y Adob e Cree k unde r aNationa l Pollutio nDischarg e Eliminatio n Syste m(NPDES ) permit . Th e extractio nsyste mpreviousl y consiste do f eleve n extractio nwell s i n th e shallo w aquifer , an dtw o extractio n well s i n th e dee p aquifer . Sol a dismantle dth e syste mi n1998 , s o thi s alternativ e woul dinvolv e rebuildin g th e treatmen t uni t an dassociate dconveyanc e system . Th e syste mcoul dpossibl y utiliz e th e existin g monitorin g well s fo r

extraction . RA# 2 woul dinclud e institutiona l controls , i nth e for mo f arestrictiv e covenan t

wit hth e propert y owner , t o restric t us e o f th e contaminate dgroundwate r tha t coul dresul t

i n unacceptabl e exposur e o f

human s o r

th e environmen t

t o th e contamination .
1 5RA# 2 woul dtak e a n estimate d1 8 month s t o desig nan dconstruct , an dwoul dtak e a n

estimate d1 t o 3 year s t o attai nth e clean-u p goal . Th e presen t wort hcos t

woul db e approximatel y $572,000 . RA#3 : Monitore d Natura l Attenuation , Institutiona l Control s RA# 3 i s th e ne w propose dalternativ e tha t consist s o f

MN A an dinstitutiona l controls . MN A relie s o n natura l attenuatio nprocesse s t o achiev e clean-u p standards . Wit hMNA , Sol aan dEP A woul dclosel y monito r th e groundwate r

fo r ke y parameter s t o trac k

ho w th e contaminatio ni s changin g ove r time . Thi s alternativ e woul drel y o n existin g groundwate r

monitorin g wells , s o i t

woul dtak e n o additiona l tim e t o construct . I t i s estimate dtha t

thi s alternativ e wil l achiev e th e clean-u p standard s withi n1 t o 3 years . Th e institutiona l control s fo r thi s alternativ e woul db e th e sam e a s RA#1 . Th e firs t contro l consist s o f

arestrictiv e covenan t

wit hth e propert y owne r

t o restric t groundwate r use s tha t coul dresul t

i n unacceptabl e exposur e t o human s o r th e environment . Th e secon dcontro l consist s o f

th e County' s wel l permittin g controls . Th e presen t wort hcos t o f thi s alternativ e i s approximatel y $149,000 . CRITERI A 1 : Overal l Protectio n o f Huma n Healt h an d th e Environmen t Overal l protectio no f

huma nhealt han dth e environmen t addresse s whethe r

aremed y provide s adequat e protectio nan ddescribe s ho w risk s pose dthroug heac hpathwa y ar e eliminated , reduce do r

controlle dthroug htreatment , engineerin g controls , o r institutiona l controls . Th e no-actio nalternativ e (RA#1 ) woul dno t provid e adequat e protectio no f huma n health . (A s documente di n th e 199 1 ROD , EP A determine dtha t th e Sit e contaminatio n di dno t pos e aris k

t o th e natura l environment) . I t i s expecte dtha t

RA# 1 woul dachiev e th e clean-u p standar dove r tim e becaus e natura l attenuatio nprocesse s wil l b e occurrin g withou t an y huma nintervention . However , w e woul dno t kno w whe nth e clean-u p goa l wa s achieve dbecaus e w e woul dno t b e monitorin g th e groundwater . Th e no-actio n alternativ e wil l no t

protec t huma nhealt hdurin g th e interi mperio dbetwee nno w an d whe nth e clean-u p standar di s reached . N o enforceabl e institutiona l contro l currentl y prevent s us e o f

th e wate r tha t woul dexpos e human s t o unsafe contaminan t concentrations . Th e loca l count y healt hdepartmen t i s responsibl e fo r

approvin g wel l permi t applications , an dit s file s d o indicat e th e existenc e o f on-sit e contamination . Th e departmen t

ha s informe dEP A tha t

i t woul dno t

issu e an y wel l permit s o nth e propert y withou t consultation , bu t

n o writte nagreemen t

o r othe r instrumen t

require s count y compliance . I f

th e count y permit s awel l t o b e drille dint o th e contamination , o r i f a n existin g wel l wer e t o b e use dfo r aresidentia l wate r

supply , suc hactivit y migh t resul t i n huma nexposur e i n exces s o f acceptabl e ris k

levels . Therefore , thi s alternativ e doe s no t provid e adequat e protectio no f huma nhealth . Remedia l alternative s # 2 an d# 3 ar e bot hprotectiv e o f huma nhealth . RA# 2 include s groundwate r

extractio nan dtreatmen t

wit hinstitutiona l controls , an dRA# 3 include s monitore dnatura l attenuatio nwit hinstitutiona l controls . Bot halternative s requir e recordatio no f

arestrictiv e covenant , whic hi s a ninstitutiona l contro l tha t EP A i s abl e t o enforce , tha t

prohibit s us e o f

th e contaminate dgroundwate r unti l th e clean-u p standar di s achieved . RA# 2 employ s groundwate r extractio nan dtreatmen t

t o achiev e th e clean-u p standard . RA# 3 employ s natura l attenuatio nmechanism s an dclos e monitorin g o f th e 1 6groundwate r durin g thi s clean-u p timeframe . Thus , bothalternative s wil l protec t huma n healt hcurrentl y an di nth e future . CRITERI A 2 : Complianc e wit h ARAR s "Complianc e wit hARARs " addresse s whethe r a n alternativ e meet s applicabl e o r relevan t an dappropriat e requirement s (ARARs) , lega l standards , limitations , o r criteria . ARAR s mus t b e promulgate dunde r

federa l o r stat e la w t o addres s acontaminant , remedia l action , locatio no r

othe r circumstanc e presen t

a t asite . T o b e selecte da s ARARs , stat e promulgate dlaw s mus t

b e mor e stringen t

tha nfedera l ARAR s an dhav e bee nidentifie d t o EP A b y th e stat e i n atimel y manne r an dapplie dconsistentl y b y stat e agencies . Th e chemical-specifi c ARAR s fo r th e Sol asit e ar e federal 1 5 an dStat e o f California 1 6 drinkin g wate r

standards , accordin g t o th e 199 1 ROD . EP A deeme dbotht o b e "relevan t an dappropriate " t o Sit e conditions . Th e appropriat e remedia l standar dfo r th e remainin g contaminate dgroundwate r i s th e Stat e MC Lfo r

1,1-DCA . Fo r RA#1 , th e no-actio nalternative , i t i s expecte dtha t

natura l attenuatio nwil l b e occurring ; however , fo r

th e groundwate r

t o b e utilize da s adrinkin g wate r source , th e Californi aSaf

e Drinkin g Wate r

Ac t require s monitoring , whic hi s no t bein g conducte di n thi s alternative . Therefore , RA# 1 doe s no t full y compl y wit hthi s ARAR . RA# 2 an dRA# 3 d o compl y wit hthi s ARA Rsinc e bot hwil l attai nth e clean-u p standar d specifie db y la w an dbot hwoul dmee t th e ARA Rmonitorin g requirements . RA#2 , th e extractio nan dtreatmen t remedy , woul dimplicat e action-specifi c ARAR s an d othe r "t o b e considered " standard s pertinen t t o th e us e o f

GA C adsorptio ni n atreatmen t system . Th e remed y woul dnee dt o mee t thes e additiona l requirement s i f th e spen t GA C i s aliste do r

characteristi c waste . Thes e requirement s includ e th e Soli dWast e Disposa l Act 1 7 an dCalifornia' s hazardou s wast e contro l laws 1 8 associate dwit hregeneratio no r • disposa l o f

th e spen t GAC . RA# 2 ca n mee t

thes e requirements . CRITERI A 3 : Long-Ter m Effectivenes s an d Permanenc e "Long-termeffectivenes s an dpermanence " refer s t o th e abilit y o f aremed y t o reliabl y protec t o f huma nhealt han dth e environmen t ove r time . Thi s criterio ninclude s th e consideratio no f

residua l ris k

an dth e adequac y an dreliabilit y o f controls . Al l thre e alternative s woul dachiev e permanen t long-ter mprotection , a s the y woul dattai n th e clean-u p standar di n th e groundwater . A s discusse dearlier , eve nRA#1 , th e no-actio n alternative , woul dattai nth e clean-u p standar dthroug hnatura l attenuatio nmechanisms .

1 5 Saf e Drinkin g Wate r

Ac t (SOWA) , Sectio n 1412 , 4 2 US C §300g-l : Nationa l Primar y Drinkin g Wate r Regulation s 4 0 CF RPar t

141 . 1 6 Californi aSaf

e Drinkin g Wate r

Act , Californi aHealth& Safet y Cod e §§116270-116751 ; Californi a Domesti c Wate r

Qualit y Monitorin g Regulations , Californi aCod e o f Regulations , tit . 22 , div . 4 , ch . 15 . 17 As amended

by the Resource Conservation and Recovery Act, 42 USC

§§6901, et

seq. 1 8 Californi aCod e o f

Regulations , tit . 22 , §§67520-67525 . 1 7CRITERI A 4 : Reductio n o f Toxicity , Mobility , o rVolum e through Treatment t "Reductio n o f

toxicity , mobility , o r

volum e throug htreatment " refer s t o th e degre e t o whic haremed y use s treatmen t t o clean-u p th e contaminate dmedia . Thi s contrast s wit h remedie s tha t

reduc e ris k

throug hremovin g a nexposur e pathway , suc ha s containment . Onl y RA# 2 involve s treatment . RA#2' s groundwate r extractio n an dtreatmen t

syste m woul dphysicall y remov e contaminate dgroundwate r an dtrea t i t wit hacarbo n adsorptio n filte r t o reduc e th e volum e o f

contaminate dmedia . I n contrast , RA# 1 an dRA# 3 bot h rel y o nnatura l attenuatio n mechanism s t o reduc e contaminant s vi aintrinsi c processe s i n th e groundwater . A s describe dabove , Sol aoperate da n extractio n an dtreatmen t syste m fo r adecade . Base do n dat agathere dbotha t th e tim e an dsubsequen t

t o th e system' s shut-down , Sol aha s demonstrate dtha t activ e treatmen t

o f th e groundwate r

wa s no t effectivel y reducin g th e remainin g contaminatio n an dtha t natura l attenuatio n wa s mor e effective . CRITERI A 5 : Short-Ter m Effectivenes s "Short-termeffectiveness " refer s t o th e degre e t o whic ha n alternativ e avoid s advers e impact s t o huma n healt han dth e environmen t pose ddurin g constructio n an d implementation . Thi s cover s th e perio do f tim e unti l th e clean-u p standard s ar e achieved . RA#1 , th e no-actio n alternative , pose s ashort-ter mris k o f exposur e t o contaminate d groundwate r

becaus e thi s remed y doe s no t includ e a n institutiona l contro l t o restric t groundwate r

use . Ther e currentl y ar e n o wate r suppl y well s withi n th e contaminan t plume , s o n o on e i s bein g expose dt o th e contaminate dgroundwater . I n addition , th e count y healthdepartmen t

tha t issue s wel l permit s i s aware o f th e contaminatio n an dha s indicate di t

woul dno t

allo w well s therein . However , w e hav e n o bindin g agreemen t o r othe r instrumen t

tha t woul ddictat e ho w th e Count y i s t o implemen t wel l installatio n restrictions , an do f

cours e ther e remain s th e possibilit y tha t alandowne r

coul dinstal l a wel l withou t

seekin g apermi t

fro mth e county . Therefore , thi s remed y i s considere d somewha t problemati c wit hrespec t

t o short-termeffectiveness . RA# 2 an dRA# 3 woul dno t pos e short-ter mrisk s t o huma n healt hbecaus e bot hremedie s includ e institutiona l control s tha t ar e enforceabl e b y EPA . Th e institutiona l control s woul dtak e th e for mo f

restrictiv e covenant s wit hth e propert y owner , restrictin g us e o f th e contaminate dgroundwate r unti l cleanu p i s achieved . CRITERI A 6 : Implementabilit y "Implementability " refer s t o th e technica l an dadministrativ e feasibilit y o f implementin g aremedy , includin g th e availabilit y o f material s an dservice s needed . Al l thre e o f

th e alternative s ar e implementable . RA# 1 an dRA# 3 d o no t involv e an y furthe r physica l construction . Th e onl y physica l activit y tha t RA# 3 involve s i s monitorin g groundwate r

conditions , whic hi s astandar dan duncomplicate dprocedure . RA# 2 require s physica l constructio n o f apump , piping , an dcarbo n treatmen t system ; suc hconstructio n involve s wel l know n method s an dcommonl y availabl e materials . RA# 2 an dRA# 3 woul dinvolv e administrativ e procedure s t o implemen t th e restrictiv e covenant . Th e administrativ e procedure typicall y consist s o f EP A workin g wit haStat e environmenta l agenc y (eithe r th e Regiona l Boar do r

th e Departmen t

o f Toxi c Substance s Contro l (DTSC) ) an dth e lan downe r t o obtai n agreemen t

o n arestrictiv e covenant . Th e 1 8covenan t woul drestric t

us e o f th e contaminate dgroundwater , an dwoul drequir e annua l oversigh t payment s t o th e Stat e agenc y b y th e responsibl e party . Thi s activit y i s implementable , bu t

i t require s agreemen t

b y th e Stat e agency , th e responsibl e party , an d th e lan downer . Th e owne r ma y no t agre e t o th e covenant . Therefor e EP A consider s RA# 2 an dRA# 3 implementabl e bu t potentiall y problematic . CRITERIA? : Cos t Thi s criterio n examine s th e projecte dcost s fo r eac hremedia l alternative , includin g estimate dcapita l an dannua l operatio n an dmaintenanc e costs , an dth e presen t worth . RA#1 , n o action , woul dno t involv e an y cost , a s n o actio n (includin g monitoring ) i s taken . RA# 2 woul dinclud e administrativ e cost s associate dwit hnegotiatin g an drecordin g th e restrictiv e covenant . Th e estimate dup-fron t cos t fo r negotiatin g an drecordin g th e restrictiv e covenan t

i s $42,500 . I n addition , implementin g RA# 2 woul drequir e capita l cost s fo r desig n an dconstructio n o f ane w extractio n an dtreatmen t system . Th e estimate dcapita l cos t

fo r th e ne w extractio n an dtreatmen t syste mi s approximatel y $156,000 . Th e estimate dannua l cos t fo r monitorin g an dmaintainin g th e restrictiv e covenan t i s $3,40 0 pe r

yea r fo r a5 year period . Th e estimate dcos t fo r operating , maintaining , an dmonitorin g th e extractio n an dtreatmen t syste mi s approximatel y $100,00 0 pe r

yea r fo r th e 3 year s tha t

clean-u p i s projecte dt o take , the n a n additiona l 2 year s o f continue dcomplianc e monitorin g a t acos t o f $8,00 0 pe r

yea r (tota l 5 years) . Upo n obtainin g assuranc e tha t th e clean-u p standar dha s bee n me t an dmaintained , th e restrictiv e covenan t

ca n b e terminate dan dth e extractio n an dtreatmen t syste mca n b e removed . Th e estimate dcos t fo r th e restrictiv e covenan t

terminatio n proces s i s $4,000 . Th e estimat e cos t

fo r th e extractio n an dtreatmen t syste mdemolitio n an ddemobilizatio n i s $90,000 , whic hwoul db e incurre da t year 5 . Th e presen t

valu e cos t

fo r RA# 2 overall , incorporatin g th e up-fron t

an dcapita l costs , operation , monitorin g an dmaintenanc e costs , an ddemolitio n an ddemobilizatio n costs , i s $572,000 . RA# 3 woul drequir e n o additiona l capita l cost s fo r physica l construction , bu t woul dincu r th e sam e up-fron t

cost s fo r implementin g th e restrictiv e covenan t a s RA#2 . RA# 3 woul d incu r ongoin g annua l cost s fo r

monitorin g natura l attenuation , a s wel l a s monitorin g an d maintainin g th e restrictiv e covenant . Th e estimate dannua l cos t fo r monitorin g natura l attenuatio ni s $18,00 0 pe r

yea r fo r th e 3 year s i t

i s estimate dth e clean-u p wil l take , followe db y 2 year s o f

continue dbu t

decrease dcomplianc e monitorin g a t acos t o f $8,00 0 pe r

year . Th e estimate dannua l cost s fo r monitorin g an dmaintainin g th e restrictiv e covenan t

i s th e sam e a s fo r

RA#2 , an dth e estimate dtimefram e fo r whic hthes e cost s woul db e incurre di s th e same a s well . Upo n obtainin g assuranc e tha t th e clean-u p standar dha s bee n me t

an dmaintained , th e restrictiv e covenan t ca n b e terminate dan dth e monitorin g well s abandone do r demolished . Th e estimate dcos t fo r th e restrictiv e covenan t terminatio n proces s i s $4,000 . Th e estimate dcos t fo r th e abandonmen t

o r demolitio n o f

th e monitorin g well s i s $34,500 whic hwoul db e incurre da t year 5 . Th e presen t valu e cos t

fo r RA# 3 overall , incorporatin g th e up-fron t costs , monitorin g costs , maintenanc e costs , an ddemolitio n costs , i s $149,000 .

1 9CRITERI A 8 : State Acceptanc e

Stat e acceptanc e indicate s whethe r th e Stat e i n whic hth e Sit e reside s agree s wit hth e preferre dalternative , base do n it s revie w o f th e RI , FS , an dPropose dPlan . Th e Regiona l Boar dbega n overseein g cleanu p a t th e Sit e i n 1983 , prio r

t o EP A involvement , an dsubsequentl y performe dth e suppor t agenc y rol e afte r

EP A too k

th e lea di n 1989 . Th e Regiona l Board , however , ha s no t bee n involve da t

th e Sit e ove r

th e pas t decade . Whil e preparin g th e Propose dPlan , EP A contacte dth e Regiona l Boar dt o solici t renewe dinvolvemen t

an dinpu t int o th e decision-makin g process . Th e Regiona l Boar dinforme dEP A tha t

i t consider s th e Sit e t o b e alo w ris k an dtherefor e no t

i n nee d o f furthe r Regiona l Boar dinvolvement . EP A als o contacte dDTS C regardin g th e Site , an dDTS C deferre dt o th e Regiona l Board . CRITERI A 9 : Community Acceptanc e Communit y acceptanc e indicate s th e publi c suppor t o f agive n alternative . EP A maile dth e Propose dPla n t o th e residentia l an dbusines s addresse s withi nahal f mil e radiu s o f th e Site , solicitin g inpu t

fro mth e communit y throug hth e publi c commen t process . Th e mailing , whic hinclude dbot hEnglis han dSpanis hversions , wen t ou t o n Tuesday , Januar y 16 , 2007 . I t announce dth e publi c commen t perio dwoul dru n fro m Januar y 2 0 t o Februar y 20 , 2007 , an di t announce dtha t

EP A woul dhol dapubli c meetin g o nJanuar y 24 , 2007 . EP A maile dou t a n additiona l announcemen t t o th e sam e partie s o n Januar y 24 , 2007 , extendin g th e publi c commen t perio dt o Marc h6 , 2007 . EP A hel dapubli c meetin g o n Januar y 24 , 2007 , fro m6:3 0 p.m . t o 8:3 0 p.m. , a t th e Petalum aPubli c Librar y a t 10 0 Fairground s Drive , Petaluma . Th e purpos e o f th e publi c meetin g wa s t o presen t

th e propose dclean-u p pla n amendmen t t o th e public , an dt o solici t publi c comment . Onl y on e perso n attende dth e meeting . N o membe r

o f th e publi c submitte dcomment s o n th e propose dpla n o r otherwis e expresse doppositio n t o th e propose dremed y amendment . I t i s therefor e assume dtha t th e remed y ha s communit y acceptance . Summar y o f

Compariso n Afte r evaluatin g th e clean-u p options , EP A i s selectin g MN A wit hinstitutiona l control s (RA#3 ) a s th e remed y tha t provide s th e bes t

balanc e o f

th e criteria . Th e thre e alternative s rat e evenl y o n anumbe r

o f criteria . Th e criteri awher e difference s betwee n th e alternativ e exis t

ar e a s follows : RA# 1 (N o Action ) doe s no t satisf y th e threshol dcriteri a o f Overal l Protectio n o f

Huma n Healt han dEnvironmen t becaus e i t

doe s no t provid e adequat e control s t o preven t potentia l exposur e t o contaminate dgroundwater . I t als o doe s no t mee t th e requirement s o f

al l th e ARAR s becaus e i t

doe s no t includ e monitorin g an dreporting . RA# 1 als o present s potentia l short-ter mris k becaus e i t

doe s no t hav e th e typ e o f institutiona l contro l tha t

provide s th e mos t

protectio n (restrictiv e covenant ) agains t potentia l exposur e durin g th e remainde r o f th e clean-up . RA# 2 (Extractio n an d Treatment , ICs ) an dRA# 3 (MNA , ICs ) hav e some potentia l implementabilit y uncertaintie s becaus e fo r

th e restrictiv e covenant , consen t o f th e responsibl e part y an dth e propert y owne r are required . EP A ha s no t ye t contacte dth e propert y owner , an d therefor e doe s no t

kno w whethe r

th e owne r

wil l consen t

t o implementin g arestrictiv e covenant . RA# 2 (Extractio n an dTreatment , ICs ) wil l b e muc hmore expensiv e (presen t 2 0wort h$572,000 ) tha n RA# 3 (MNA , IC s - presen t worth$149,000) . RA# 1 (N o Action ) ha s n o cos t

associate dwit hit . I n summary , RA# 1 (N o Action ) canno t b e selecte dbecaus e i t

doe s no t mee t th e tw o threshol dcriteria , Overal l Protectio n o f Huma n Healt han dEnvironment , an dMeetin g ARARs . A compariso n o f RA# 2 (Extractio n an dTreatment , ICs ) an dRA# 3 (MNA , ICs ) show s tha t

th e onl y differenc e i s cost ; RA# 2 wil l cos t significantl y mor e tha n othe r alternatives , withou t

providin g an y offsettin g advantages . Therefore , RA# 3 i s th e bes t choice .

2 1

### VI . Suppor tAgenc y Comment

s A s mentione di n Sectio nV above , th e Regiona l Boar dbega noverseein g cleanu p a t th e Sit e i n 1983 , prio r

t o EP A involvement , an dperforme dth e suppor t agenc y rol e afte r

EP A too k th e lea di n 1989 . Th e Regiona l Board , however , ha s no t bee ninvolve da t

th e Sit e ove r th e pas t decade . Whil e preparin g th e Propose dPlan , EP A contacte dth e Regiona l Boar dt o solici t

renewe dinvolvemen t

an dinpu t int o th e decision-makin g process . Th e Regiona l Boar dinforme dEP A tha t i t consider s th e Sit e t o b e alo w ris k an dtherefor e no t i n nee do f furthe r Regiona l Boar dinvolvement . EP A als o contacte dDTS C regardin g th e Site , an dDTS C deferre dt o th e Regiona l Board . 

### VII . Statutory Determination s EP A expect s RA# 3 (MNA , ICs ) t o satisf y th e followin g statutor y requirement s o f CERCLA , Sectio n121(b) : (1 ) b e protectiv e o f huma nhealt han dth e environment ; (2 ) compl y wit hARAR s (o r

justif y awaiver) ; (3 ) b e cost-effective ; (4 ) utiliz e permanen t solution s an dalternativ e treatmen t technologie s o r

resourc e recover y technologie s t o th e maximu mexten t

practicable ; an d(5 ) satisf

y th e preferenc e fo r

treatmen t a s aprincipa l elemen t t o th e maximu mexten t

practicable . Onc e th e clean-u p standar dfo r 1,1-DC A ha s bee nreached , EP A believe s tha t n o contaminatio nabov e clean-u p level s wil l remai non site , an dan y us e restriction s ma y b e lifted . 

### VIII . Publi cParticipatio n Complianc e Th e publi c participatio nrequirement s se t ou t i n th e NCP , 4 0 C.F.R . §300.435(c)(2)(ii) , fo r amendin g aRO D hav e bee no r wil l b e met . Th e NC Prequire s tha t EP A d o th e following : (1 ) issu e anotic e o f availabilit y fo r

th e Propose dPla ni n amajo r loca l newspape r

o f genera l circulation , (2 ) mak e th e Propose dPla nan dsupportin g informatio n availabl e fo r

publi c comment , (3 ) provid e a t leas t 3 0 day s fo r

submissio no f

publi c comment s o n th e Propose dPla nan dextendin g tha t perio dupo nrequest , (4 ) provid e th e opportunit y fo r

apubli c meetin g a t

o r nea r th e facility , (5 ) kee p atranscrip t o f th e comment s receive da t

th e publi c meeting , (6 ) includin g i n th e RO D Amendmen t a respons e t o eac hsignifican t comment , (7 ) publis hanotic e o f th e availabilit y o f

th e RO D Amendmen t

i namajo r

loca l newspape r

o f genera l circulation , an d(8 ) mak e th e RO D Amendmen t

an dsupportin g informatio navailabl e t o th e publi c i n th e administrativ e recor dan da t

th e informatio nrepositor y prio r t o th e commencemen t

o f th e remedia l action . EP A maile dth e Propose dPlant o th e residentia l an dbusines s addresse s withi nahal f mil e radiu s o f th e Site , solicitin g inpu t

fro mth e communit y throug hth e publi c commen t process . Th e mailing , includin g bot hEnglis han dSpanis hversions , wen t ou t o n Tuesday , Januar y 16 , 2007 . I t announce dtha t

th e publi c commen t

perio dwoul dru nfro m Januar y 2 0 t o Februar y 20 , 2007 , an dtha t EP A woul dhos t

apubli c meetin g o n Januar y 24 , 2007 . EP A maile dou t a n additiona l announcemen t t o th e sam e partie s o n Januar y 24 , 2007 , extendin g th e publi c commen t perio dt o Marc h6 , 2007 .

2 2O n Januar y 10 , 2007 , EPA sent an electroni c cop y o f

th e administrativ e record , includin g th e Propose dPlan , t o th e Petalum aPubli c Library . Th e administrativ e recordcontain s th e documentatio nsupportin g th e Propose dPla nan dRO D Amendment . EP A place danotic e o f

availabilit y o f

th e Propose dPla ni n anewspape r calle dth e Petalum aArgu s Courie r

o n Januar y 31 , 2007 . Thi s newspape r i s amajo r

local newspape r

o f genera l circulatio ni nPetaluma . EP A hel dapubli c meetin g o n Januar y 24 , 2007 , fro m6:3 0 p.m . t o 8:3 0 p.m. , a t th e Petalum aPubli c Library at 10 0 Fairground s Drive , Petaluma . Th e purpos e o f th e publi c meetin g wa s t o presen t

th e propose dclean-u p pla namendmen t t o th e public , an dsolici t publi c comment . Onl y on e perso nattende dth e meeting . EP A ha dth e meetin g recorde d an dproduce dawritte ntranscrip t o f th e meeting . Upo nissuanc e o f

th e RO D Amendment , EP A wil l mak e i t availabl e t o th e publi c b y placin g acop y i nth e Petalum aPubli c Library . EP A wil l the npublis hanotic e o f th e availabilit y o f

th e RO D Amendmen t

i nth e Petalum aArgu s Courier .

2 3

## PAR T 3 : TH E RESPONSIVENES S SUMMAR Y

N o membe r

o f th e publi c submitte dcomment s o n th e propose dplan .

2 4

### FIGUR E 1 : Locatio n an d Exten to f Contaminatio n Sol aOptica l USA , Inc . Superfun dSite , Petaluma , CA Decembe r 200 6 2 5