NT TO THE RECORD OF DECISIONOlE'ERAJLE UNIT THREE

WHtTMOYER LABORATOJRIES SlIPERFUNTI SITE

Site Name: Wliitmoyeir Labonutoiries; Superfund Site

.Siite Location..: Mlyerstowiri,. Lebanon County, Pemsylvairia

Leeui igency: U.S. Environmental Protection .Agency, Region ("E.PA" or '"die Agency11)

Support /h.;E;ciri(;y: Pe:mis;ylvania Department of EnvirQiriinEHiital! Protection! ("F'ADlEiP")

A Record of Decision. ("'ROD") ifbr ilu: Wliiunoyer Laiboraitories SLipEirlimd Site:("Site") for Operable Unit Three ("OU»3") was issued on n>o::<:niber 31, 19!W. This

in(c) of die 'COTiiprehenisive Environmental Response,, CoirnpEMisation md Liability Aci:, a.samended, by the Supeirfund ^LnrtBi:Khirients and Rwiuithori^aLiiion Ac\. of 1986 ("CERCLA"), 42U..S..C. § 9(il.7(c)., and 40 C.ER. § :KX),43!)(£:)(2)(i). Tkis Anieiruiine;nl: has been pirepanid 1:0(l.cK:uLH:iK«i!t I]:DK [Kiiitu.:! ; ol: ithe c:]wjri||:(2: irna.de let die: seliectecl I'lEimetily i(]k;nnti3fijEscl iiri th«Ei 'ROD forO'U-3; to ,5PLii:nrtiajrli:<: Uhe i.;ril:0]:«riai:i<]'Ti that led t<]i the nria]<:ini;E; of tlinE: i::hi3.tij3;e; a:rid 1:0 affinn dia.itthe revised remedy complies wiith nhe statiKory req[iiHemeni:s; ofCBRCLA. § \2\, 42 U..S..C,. §9621. TlinEj ,EunKKncln]«::rit: ifijitMJIaiirLEniiital!' 1 aJltets tine ireineiLl; selected. i.;ri ihs ROD f.tw OU-3 wiiihire:;s][K;cit to SCO]>E:, performance, ai:Kl cxjisit. Tlids .^kincniiicbirkcitkE is iiicoipoinaied into UhcAdniinistradve Recoird for die Sii:e .

Tlii.iS. jncHixInieTii: cliniiimntKS thus; ]re:i:|U.]Lns;niiei],i: ito ei^ca^-ate sa.ituira.a;<i! soilis. ioc;3,te(]l bslow(her v/iSLtet labk. All Siaituii'iate:*:! sioils c>rijj;i]]i;aLl]y tajr|2;et(:d lor i;::»:ca:ai:io:n an; loc:ai;ed withni tinecaptuinss zone oi' Ijtu: j];rou::tujl 'H'ai Kr :t]r'a.cti.oni aj:Kl iieaiiii nit .ssys ssini aiiujl will be ireniediiaited Adsai. •C'Ln'Kl v/.aier remediation. Tliis Ann:ncJmc;:il t:l iininale.i i;ht: i;:ist;rll;] tion of i:tie c 11-5.heimpermeable cap bu\: rcqiiirKs; tins; conu&itrucuoiri of ;ai c:o\rt:r of \:wo (eel of Kktan soil overnioderale'ly ci;>nita]:niii],atedt isoilst. Ifeavily coniitanniiated lurisaliirati^id so'ilh; will 1t»e excavated inaccordance witih ih& ROD lor OU-3 mid JiJiplaiLantion; of Significant KHITerences ("HiSD") No.3 and treated! (ais necrejisajry) prior to off-sits; 'CliiisipoisaLl 1111 accordance with die FhasB IV Lnn:\Disposal Resi:rit;l:.io:n:s (63 Fed,. Reg. 2855 (May 26,, 1998))., Tin's Amiendinenit eliminates ilu:rK(]iiijre::ri]nE:n.it to i:r ai: or.|;ajrii.i::.ELlIy coiil Lrninjaited isoiLsi via o:n--sh:e ]t»iorE:inc!diai:io:n aiibd reijiniiresolff-jj;iie: i:real]rn.en.i: of tling: or|!:i3LnJn;:a]]3/ (;c»nl Ltnin;3Ltei:l soils; by ]i:»v -iJE:inpe:ri3Ltuir<s: itli«::nrnaj (le cn tioiri(see Table I),.

1 This Amendment pe.rtralns only to t:h'Sj spec:LJ:;Led portion;:; of: i::h(:»ROD :f:or OQ-3 . Three 'RO'Dst have been isissued lior the WhitrnoyerLaboratcriLes Site. The HO'Di-j iror OU-1 and OU--2 are explained inthe Sit:e history and are unaffected by chiisj Amendrnent:,.

OlCnim [i;3tiT::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

IMlwtliiaJtie.j3iAni.lv L-oirilaminaled Sous(Unsatiiraled)

I Heavily 'UoiilainiiiaijEsd. Soils( Saturated)

McdeiraiEsly toimaniuiaiuEsdSoil* (Unisaturated,, on-site)

Soils. OJuiatinated, olT-siiDEs)

Soils; (Saturated.)

Li.;E;liLti.y coiiiainiiiated soils

Sediihents;

Soils (SatLiraitfsd.) '

Soils; (IJnisatiHated)

Nol:es:'• ,A,s part of am Exp'llanTlinse aiid. Five: (lagoons,

Five (laijjoomi to'd'U 11A.s part of the ]Sf(»'Kiirih!!2:rWEIS' cl]Li3Lii]3|E!dL Kt> allow l:or

Ij-iJ^iLE 1J TlnnM2 (!knls E»:ujl SediotiiLifsiiiisisj[n]i nl; Ift.t.) D ajtid ^iJtiMC'nalJ^fi '

1

RODReim.ed.y

aoci oiEf-isite disposal. 'Saiii!: as Eibovc,

I K.cavaiion., boMSolida'tioin(::[!-=, il.(=; hi. via losiE: :;;nnE: underan :iin[3e::[Tne:;3Lt)lnE: i:;0'\rEsr,backl'ill of excavated ajreajsdeed :n:::s>Krici:ioti!>,Same as iSbovii..

?!!(3rKr 1wi!itii i:wo lfee3t >o1[ ci(;;anis oiJL, <jLeES(]i ireiilitictiafLS., Rcaicdiaiioii wii(;:r!: soilsadjacent to c;n;ek or canalrEiil'Lii e; rcriic liiuticm.a.i:x:c]'i[(Jl'in;E; to irnethodis. airidc.'nt<::n.a 6\. iriiCKli raiteliy andltiea.vi.iy crc^n^Lininatca soiils.

ixjllo'ii iMJl by i:rcatmeint ofa.ciL MffJiing to criLteiria atui

xj,3J[ii.c a, ,i> -\ ...

Sacneas&OD1,.

'Thiai'rii.eiii: via, die jrroiinciw^tcr piainp' and. tj[<f:;3itsvstein, K«/O-|I:K>IL clean s;oi.lci:»vi::rt d.i E;d rEss(3rin;:tinC)Hw;. !T':reat]:[iei!i, via ibis riSiailci'wauer pu.'tn.p aiu;l trtsatsysU2:;nn, iwolfaot cksao soilcov«i:!( i:lee;d nsisi'tiriciticius.

ciii'-siKEs iincleic a i i'O-l'obt soilcover, ttealmcat via thuEsEjW'Und wim:r puitn.'E* anidiirEsai :=.ysio::[n.p back1:ill oi'Es :cavated areas, desedrEssljriictiiorLs;.T]fi:aiiif!E:i:Lt viEa tliiis: j roijiiid •\vt\\:w p\im$ md utatisy ste rn,, , t o-l'octt .cileisin. soils

Same as .KUlK

Saiiie ais ROl>. 1

TifeiiiinEiiiiLt vna "tiie jsji'ciiiiiii,w<\\r.'.i' pump \\iid utat >system, two-loot i le;3in soilCOVEN:, dise<Ji ireistticiioitis.

l-:xcavatinc!i]i, oil-sitel:n:atnient (as incjco tv),aM disposal.

Ettiion of SijiinMcant Dilffereiice -(ESD) ito- ihe RODs for Oil's, daJDEsd Niovsmrihcr 1(5, 19ti$, tin;: m$ ibrtiu iiv lawwn a.:s. tju;; i]rK;liad.(;:d in die remedy for scilis. I (i.e. UiaLnslEsrre'd l:r<;nn '(Jii 'tree (soils and sedimenti;)}.Ifi.j 199$ BSD,, the: remedy for heavily conla ninaited soilsolft'-siite,, r;3Lth<E:r diaii on-isaie; iKsamiem: 'of soih.. . Vs itlidsbv USJEP'A,, it i.:s not addressed l:>y tlnis riEsquiEist for a RU'D

HR302Sl.i3

.SJpEsciric information acquired during the :Reniediai Design mid related clean-up activitiesincluded die following:

» Soils do not appear i:o have been the primary source of arsenic in ground 'watercontamination.

11 The arsenic plume in .ground water ai: die Silts: appears to be: stabile,,

11 Arsenic potentially leadiing from contaminated soils will I>ES captured by the groundwaiter pump and treat system.

" The expected volume and depth of moderately contaminated soils ito b® excavated hasincreased substantially compared ito those estimated, i:ri thus: 'R(JD Ibr OU-3,

» Technical |Ma.cticability issues have bee;n identified 'with Hie excavation of sa.tuira.itedsoils because of the sigmlkant increase hi the volume and depth of soil to b«excavate:!

Bach of itlicfls: points are discussed in detaiil in. Section IE.

II,. SinVffMARY OF THE SITE HISTORY, SELECTED REMEDY AND FRJEORMCWIEICATHONS

I'tic \V'hi; titioyej: Laborai:airk:s; ,Sitc iis ttie locaition of a former veterinary ]fe<jd a£]diti\res andphajrniacenticails in.EiniiLJiiaKi^Liirijriij; ifiicilily. Pro<incdc*n be#an i!nt thus: iS>i.itB in 1.934 and i:n tJ:ie rnid-1950'' s, th<: 1:acllky l>B{!;;aLt] u::s;:ini]E; arsenic ijri thv proclucition of feed adkliitivBS. Othtir proclucitsI>TCKJiu:ei:l imcluided a :x, i:\-i.u dip, \nw\ to treat skin disorders; pi]x;rEL:±[ie,, a ' on:tnnj=; atient;ai:id suJEf'ai drugs, used to inhibit bacterial! growth. In addition to arsenic, a num.be:: oi'p]:o;lu::L; ina]:tLiifacitujred by itbe facil iiy ::C[\I-.\K.(\ aniline, an organic chemical <deiri\^ed froni

'Tbe: c»iijf;inijaLl Sii€ o nei1,, C..W. V/liil]rnoyi2::[', Sir,. »lcl itlie; facility to tlinE: iRLHJtiin istncl Maas<;!(>]rn.pa]:iy ijri 1964. hi 1978,, Wohnn amd l-laas sold itlie ci:>m[3a.;riy 1:0 .BEsecltiauri ITIC,., who in itu.:nrisold thus: facility ito Slalifbrd l.-al>oiraitO]riies, Inc. iiri 1982. StEiffbrd L,ab<>rai:cn'ie:s., Inc:.. filled forC'hapler 11 b'i3LnJ ni]:»tc>f in nukl"19&4 ami continiLied i:»p :r;3itioi] at ttie Sitasi uiutill Jajriu Lr)' 1913:7.

EPA Iwgm asi«s;;s;in;ES Sito coodiiiiooE; in 19W. How«ve[\ w/ltifsn the facility closed in:19E7V thus: :Resomn:e C jiiSiisit 'a.don. ajrui. ]El.ec:<]i>'ei:>' A&i ("RCFA") ClcusntrE: l]laj:t had oiily 1>Kcn|ji3[[itially ini|3derrHMrLte:d, Ilte Site 'was listed on tlie National iE rioruty List ("NFL") in 1.986,anKl ll'troiJifsliioiJit 1987, EPA. conducted numerous sajrnplknii; activii:i«!i,, bc»tlii on- amd off-siitc. In19H8, EiP1, ren:io\'E:<Jl i3ippix>;<:i]iiate]y 400 d;n.nns from (lie Site whik l)e:;En'jrin:in.jE; ;EL fund-leadRemedial I;rivesti.gai:ioii/Feas.ib:iliity Study.. A ROD for Operable Unit One ("DIM"') wasissued on June 30, 1989 for Ufa: t:onjiolklai:ion., rcruovijl and itRjatinent of concentrated liiquids

4

aixl d^ECOTiuaLininatiLon of 32 tanlus, and. vessels. "The OU-1 'Remedial .Action, was; completed inSeptember 1990.

The ROD for Opeiabk Unii: Two ("OU-2r) was issued on ttecembet 17, 1990 andaddressed the concentrated 'wastes in the: concrete vault, wastes abandoned kn two groups oflagoons, products. n::u3 i Li M ll.an.iM u.:. ninairials abandoned iin, buutlimi ;, and tJ"u: building,:; andKiljitcd isntnicitujHja. V*L carupletK description of die !3«:!lBCiCBdi rei:nedy us v/is;ll ajs, EPA's rationalefour |]:LB d.««:i.jiii'Oi:L :is ]prE:sE:nitedi iin. tJtie ROD lc»r OU-2,. I'lMJ majior coirn,]:K3iriEn]Lits ol: the se][ec:i::dreme:d>r WKIW:

11 Chi-ste incineration of die high organic content vajult ' Miit:es i[aJ[so rE:lent::d to n& t:t«:"•u.]f»|>EM' 'aijilt; wastes")i comitents {)lE"buri«d idrHiinus. liocaitedi iaidjiiaLCent t,o the: \-auJtt., n saduial.

and combustible de:i:iioliitk>n i:l£;bris iEi«Jtu.bi.tin[[ tJtu: RC!'k/i. a:r eiru,c toxicity characiJEsristic,

<> Fixation of lagoon, wastes, incineration residual!), and iow oi-j Jii.c c:o]]LtBi:Lt vaidt a»t<E:s.

• Sirface cleaning, and demolition of co:nt Lininat: :d structute*;.

isealuiji; all noKnoibujsiJblc, p :[:rnj2:al] : tl.««noliLti.on dt:bicis exhllTiitijng dieii.c t'0; i(:iLty chaiacteiristic.

Sunace cleajrii.][ij> I'tic iioiiconibuutiblf:, i]:n]>E;nnea1:tle (ktnol.ii.iGa debns lEixhibilJing dn :]E(jC ]fl. L arsEindc toxiicity characteristic,

1 Disposal of die :[ol]o<vm.;t; ii;i olT-siitt: land 111 LSI: tine trE ated, wastes:, this: ian.i:['i:iEm=:dno0|] 2:anlon.s ia[;oon wajji:£:s; the: ULnti' ai cl noahaxaidous [i][isce][laj:kEU]iLs][n'(]du.c:ts/fbE:d,!Stoc.]ks; iu\d ttie: uinttiE aU cl i]i<:)iitia:z LrdoLi!i tliMn<:ili.ti.on. (jlehfi s Utiat its nm:salvaged..

C] n, ][]ieceicn,bBr 30, 1WC),, ithns; iiinaJl :R(3'D Ifoc G'U-3 vas issmsd. lit: a ldjte:is!i<:cl i;;ontajrnIna.itE:(3isoil:: airid a<:lj;3.i::E:nf[ :siodii:mLents, nioi:Ltia:?:ELrclot]:5 bjildin s, md ]2;['ou.:[i(i. water. I;tie majorC';m:i|>;)rt£M]J:s of'ihe ireitnedy nichidEui u aim ni: of bea.vily contaminated soil actid :;cdini(::riU3,o;api[>i;rij3; of reniaunng <::{)itLta][EiJLnaJtB(]L is iiJls ;aind is liLniKEtniiis, buiiJldJing LlEiKrioliKicai, wcy(:\mti twdisposal of debris, and pumpkng and itreatmiemit of cof«aj[n.iLna.itE;(], ]3tix>Hjrid. •water. In the; ]E(.O1C>Ibr OU-3, U.S.. EPA iMltuid mh\ ;ELS llijsjliiitly, oiotoatKly,, or lti«a: i]ly 'C<Hito[mdnaited leased ontJtie kwrM of iaLrsetik; prBSBnt., ;ais wdl as 'by thuBijr |Tire:!3e:;nce: a-bo B or 'Iwhrw i\w:> grouitHJi muiital>llE: (t.'B., ui:[»ia.l:u]ra.iDB(l v:s;. saliirEU sd soils)- labile 2 summarises nbe; action ciriftBiria. (JiefininLiE;i;:ach c:aie:go'iy of soiii annil itlwss :3L;si:s;ociial,e l potential risiks,, ;3isi iidenliiliied. !:>y U.S. lEiP , in ttieROD I;OT OII--3.

AR3Q25lf5

Siniiiinajry

CaitejijiO'iry

Heavily 'Contaminated Soils

Moderately ContaminatedSoils

Lightly Contaminated, Soils

TABLE 2 :of AcliioKi Criiileriai for Arsenic in Sni Is

Actiioifi 'Criteria

!i iB||;/L. according to tli«;To;n:icit>r ("!lL3Lt'acl: ::[ist,iK:

1 LBiiching If'roceJure (TCLP)11210 tnE;/k:g (:iatu,:raied soils)4!iO im,E;/l:g (uLHJsaitu.]raitB(3[soils)

21 mj»/lqj (lbac]kj|;:n:m.iri(i!)

iElasis

l]loi:i2:iil:iaJ: oni[)ai:it to jSirowiTMi.'Wai;B]'

Pot«Biial kiipaci: to nionndWlttffX

Pc3tEmntiaJ exp(]'!3i.Ln£: via.cleitna.1 caniact. inhalatioiuor int;c:=i:ion

Note:

Heavily contajriiiniated soils; were oiri.gijruil.ly defined, iin (lit: ROD for OU-3 as soils witharsenic: conccntration-s greater than. 1,OGO nn /kg. Based en the June 20, 1995correspondence from W1.P.SG to U.S. BPA (accepted March 1.1, ]19%) the definingcriteria ibr heavily contaminated soils was subsequently modified 1:0 !> nt\i/L TCIJ3'-arsenic.

Tlie ROE* iov OU-3 [ie:fl:ne<j[ or.[;ajrkical]|y cioni-ELniiiJiate^l soils as those exceeding PrincipalTlit'cal: Levels (FTLs;) \\ir i::EMia.in C'T'ja;aiiic [:c»inip<:cLinicl!i wf concern, && shown, ijri Table :L/n:x:o:tp):li.:ri|]; to ijtu: ROD for OU-3, Iin£:av1l>r iain.d organically contaminated, soils were to' beexcavated above and below the 'water table until liie top* of bedrock, bimreirnediated on-sitiE: asnecessary for removal of organic conutaniinaot!!., treated, via, fixation, a:nd dispnosed of off-she.Motoatdy con.tanii.:[iai:£;d soll:5 W.K> also to \w cxc:a aa:d 1:0 llte top of tn;i:lroi: k amclconsolidated on-site ahov : the: w&twr table under an inipemieablle cvvvr. Lightly contaj:rii:nai:eclsoils; 'wc'ire: to he covered winh two I:BBI: oi?clBaB soi.1. SBdinru:ou> wxw to be ireniediiited in. Utu:isajrnc irnanner as sioils whai \h$y 'ware located adjacent to soil retinediiiaitlon a-reas; a:ru3. i'ere inexcess of criteria Ibr irn.cKi.«:.naLte]ly air heavily contaminated soils;. Ai: the completion oi:conjsmiction, d<s&d restrictions 'would be uis^sd to control aci:ess ito contamij:iat:i::d sioiilsremaining on- or off-siitB.

It i:3 c!si:inia.itBdl tha.t c;nnstn]cti,on oi' llie oiri iiriaJ OU-!I rBnriedy mmhl lake approximatelyfive >Fea.;r'S \o complete, l riior t<3' i[rn|)].(;::[nn£:ntat:ian of thus: remedy, contaminated area.is v/ou.ldneed to be clcajn l, HIB Tulpeihocken <;)reek and Uiriion Canal,, 'which traverse die Site, wou:need to be re-routed., TTte Lock on ithe Union Canal, thongtu to Ix: of historic value, wouldirwMJd to ibe disnnajridled.. Wetlands near the site would be sijEjuificanlly knpEicted, if n<jit

AR3025US

destroyed during excavation activities,, although tins; could be mitigated during Siterestoration

'TAJMJ:! 3Actnoin 'Cirfteriiai Ibr Ori aniicaJlly OiMiitauiiLiKifliited Snita

(Principal Tlirail: Levds, TTLs)1

]E3 :ti:!:<E:ne;ll'i'anjs-l ?-r)ic*lilrn'(»xtlnBin(a>*Tricblornethene'retraclnkn'oe hnsine:PyrEsnis:Y\ f \\MAiitt\t\ )pyii.nil:S«]Cu:o(b)i'ni'UJ:>ranthLBi]ns:n- fiitrojs.cKi.iplieir 'lai iine;Liiil.iniis;ldenn(l ,2,3-cd)pyren.e

_j »l __200io 114

26,23021018 11141250

Noite:

1 Action, ciriteick as deified by ENVIRON oorFCispondence to U..S. EPA, June 20., 1!»5(iiccepted March 1.1, 19%).

iJn December 28,, I9W, El?A mmd an ESB Utial: nicKliil'ied, t:tie rBiinedy \o -dim* this:1bl,]L(3''«nj[ij|; materials \o lie; iLiiciniErnaited iai!t an oif-siiie ifiidliity:

" L,a|]<n-at:<:)ry botlles;•> 'V<:«]N[|<!ii de:bri.:s. Iri'oni. Hie vat'Lilnt;•» TrartEilbrniers; ( ith tuid ithcml: dE:i:( ;;t;s.ble: lE'C'Hiisi):;'« C'nash ncl (JLEiLinris w/ilJn lEulJriBrijr , l3aLr-lilc:«: material;•• Unexpeeited isiolid. iuidl liquid v/iaiSiites Irotni tiie \'an,!it:;<» ;f4i1:s ;iE:l.]la]ie(3HLis n:iat:iE;ria]lsi lEirwicn (>ici-:s;iM:: buildings;« 'V c»>;leii tajrilcs; mid process; vessels; and« Combustible demolition debris eidiibiting the tiLClEOV airsei^ic loxiclicy cbara<:tE:ri!il:ic.

AR 3 0251.11

ESD No. 2 wiSLSi issued on November 7, 1995 selecting off-site treatment. aiKl disposal ofadditional wastes originally determined! to be treated on-site,, E$1D No. 12! documented tJtiedecision to treat tine following 'wastes iait ofi'-islte treatment and disposal facilities: 1) anilinesiitiJH-foouoni tars and, carbon/iar wastes (Lriciineiration), 2) wastes wititi elevated levels of organiccompounds, i.e., liiel and waste oils, andline residuals, and organic product residuals(iLnoineTation):; :S) calcium anienate sludge from the Iowa- vm\\. (stabilization,); and 4) 'wasteswith, a limited, amount of organic compounds;, i.e., ;[].ooir sweepinj^i, concrete residuals,, wood,and debris {

An .Amendment to Hie ROD for OU-2 wajs i&m&d on May 12, 1998. Hie AjiiusndmeniE totfie ROD for OU-2 selected (]ff-,siil;e :stabdliLz:al:it]n and disposal of vault soils.. Ilie o:[:t(|l[iJ3ilrenried;/ selected for titm v asl:<;: striEiam m& oti-Eiil^: ;im::iii!is::nj.itioii fo][loAve:d \iy Mobilization, ofrBsidual Vi/';3LSit«s ai:tci oi'f-site dii;s;pos5Ll,. Hie /irn.(2::ndl;[n.i2::nt elininiaiied the: nnss-Bti to c:oii!il:[uc:i: ajcion- site iucwnalor by jj lowin Utie final w/;ai;S!itB streajfn oiri ijria]! ' selBciiBCl foir oii-iSiilj;:iiriciirieratioii to be \$\mi to an cilT-sitE: Uxiaiioo for i:re;3Ltnient ai]n;l

lEiSD No. 3 was issued on November 16, 1998 nK>d:ilyi.:rig; the RODs ifbr CHJ-2 and OU-3..B!SII No, 3 changed tl:nB treatment location of lagoon mated EL! s arncl lieaiviily i::ontaj:ni[;na,te<j[ soiLs>(iroin oil-site to an, off-sice treatment iacilhy,

ML REAJiONS FOR .LSiSUIN'G THE ROD MffiNDRIEMT

]!)uri]:L,i; ijrH.];>l«::rnjKiutal:i(j:ri of the U.S. E,P^L-iSipproved l einexlijjJ Design ('"RD"), the:respoictsiible piEirtksst, collecitively kjru]a n a.iS. Utie \'lu.tinK)>'iE:r Laboiatoties I:i;rivi3.ite !situn:l>' (:frc]ii[>("'WLP'-SGr1'), conducted .ad.dition.al i]cive;:s.itija;.al.ik)iitsi \:o Bvj3Lhj.iaLte ilie e:citent to 'ivliLichi roiiini;! w^antei:was coiiumtiuccd. tlu i :relai:iom;hip between contamlna.tio.n in Site stnls and giroiiDEl v/aicr, am:ltJ^ie extent of soil contamination, They also ohtciined design information such w& l:he \ro][niirieand depi:h of soil:; to he: excavaaid, and tiie thu;lax;;=:; oif saturaccd ;soils. Thi:;i]- rindiaj!:= c;].n t)eIbnnd in utie ft]llcn in;E; 'Cioc

Remedial 'Design Water Quality fnwwti&wtiGw: Opembte Unit Six Ground Water,Task Repon (CtooTirajrts 1995) ;

•• §oih/S$dimmt$ Ghamcterization Ri'sidts Report (ENVKRON, 1994;, mr\sw\June -19%); a:rid(

•• Lmenmi SOiib/Sailmenty Ddinaition Program Results Report (WV\MM.t November1998).

C!onla;riiinated .soills tlo .not appear i:o he: \\\\& piriinary cootribuitoirs oif ars^EinJc \o the groundwater at the flute. In 1995, ground waiter data was -collected up>gradient and dov/ngtadiient ofpotential source areais., including areas of heavily and moderately contanrtiiiaijEsd soils, and. tfiecoiuioliklaited lagoon^,, tlinB e;(.i::av;aite:cl lagooms,, and the vault structure. Appreciable changes in

AR3D25U8

arsenic concentrations i:n the ('round, 'water 'were found as m\M passed beneath the;consolidated lagoons and va.uil.it structure. However, lliese same increases weira irioit observedin the areas oif contaminated mis (GeoTirans, December 1L9M). Also,, connpai d. t:o 'wastesfound in the: consolidated lagoons; and vault structure., soils had liiignil'icanlly lower leachablearsenic kvels., and a lo'weir average concentration of arsenic. The consolidated lagoons andcontents, of title vault structure have since been ireirnoved I'toin the: Site.

Additional ground 'water sanripli:i:i|2; w»\s conducted. to\i ihB OU Six. ('GircuLind V'ale::r) R]D,,airicl titie results were ireiported in the: "Remedial Design Water QmUiiy Mwsttyatim: OperableUnit Sh: (Gmmtiwifw') Talk Report" prepared by GBoTiaius., ioc. (Deceirnber 1995).Greo'Trans foiand tliait, title nature and 'extent of unround watex contamination JLEI 1995 was siintilarito ttia.t ibtirtd biy U.S. EPA (\n\m\g the: lEljBiiriBdLiaJL Investigation (R][ Repent» 19119}. 'The: shape:and 'E::ttE:nt of tine contaminant ][)].iLirtie: heid. dian,[[(!;i:l -\m:y little, no tie'w cheitnicaJls of cxirKternWI/'I;:IIE: identiried, \md the: ni&xuimim l.«!-v«ls oi: jail], clt-ieiiciicialii of concern ItiacJi decreajsad.. Inaddition, title shape and extent of the arsienlc ground iwajter plumes in li)8" aj-id 19!3».!i W^SMIBfoiund to bB sinrii la]: to that found during a hlstotic study performed by tine United SlatesGreolo;[;ical Suivey (Wood., 11973).

The stability of the plume from 1973-4995 indicates llial: hydro|!;eolo||;ic porocBsses (be,,th'B ground and surface ' ater bodies) developed a stabilised system thai: balances* scarce:releasEj with itiatLirali attenuation,, Tulpehocken 'Creek, which, runs irioirth of the, site:, appears toact as a natural! barriex to liirilier migration of ithe arsenic phniitt, as demioniS'tiated try tins:shape of the; plume,, 'which parallels ihe creek. 13esi|2;n ol One ;E;roun.d 'water pinup and treatsystem, now operational, (bcus-ed on ]renn;:di.i3itioni of Utie most hi|j;l)]iy {X3nritj tiiini;3tte<ji ground'w/a.iter {grBal r tti;3:ri 1 part per million). The entire Site and all ofif-i&iite ajre«nsi a,t -svliticltiC(]>:ntaLtniniaLte:d soi>!Ls ai'e found fall within the expected, cap tun: zcnte., IProirn liie capnare :i:oine,,ccmtaini]:Lal,i::i;l [[ oinrKl. ii'EU i-r iis pinniped through a. network of e::K:ura.i:tii:m wdls mil pipes;,, itt]- theon-site trE;atninE:nt yst n. (!!i:»nitarrij[tiajtkl:!s are removed JLU a pirec:ip>:ita.tion p>]roc;ess (whichgE:r i':LH::5 ;JJ:L ars :nJK;-'rich !slud]j;e} aind tin:: treal:iE:id v/ iter politico iin, a j;::nj:u]'iaii:l cairbon systemprior to dlschatrge: t:o the 'Tulpehocken Ci Bk.

Tims; grouind waiter 'extraction ajridi t['<Eiai][ii,e::ni: !i] s.itBnri 'tuns b :en. e1fibc:liv«: si:nce: iit he^an(]pe]ratin|; iici Aprril 1998 hi accordance with all relevant PADEP iwqijiirements., The sludjge isdisposed off-she in ;ai ite:guLla.tE:<3l disposal laiiilily. Thus,, i2irs :njn:; tha.it way inigtate Irrorn.sa.tujraitE:(3i soilis; or from, ijtie iiricncl«::ri3Lte.]ly contanrnjriacea:! soils ' o'iili[l lie: rE:cove:ii:e:i;l viia the pumpand treat is>fstern artd reiiriovt :! horn tine Site foi di:sipo;si;3L.l as an arsBiiic-rich islndi;e.

'Tims: ScALs/Safimmfs Chaniawimtim Reside Rtuwrt (1996) aiKl Interim DdinetuionRepon (1998) incliMled analytkaJl results firoin OVCT l.COO soil. and. sediment samples. Thesedata WBI:B conibitied -m\.h the: W. data 'to estimate tins: volume of contaminated isoils forcomparison to those estouiales presenled ii:i the: ROD. Although ithe: vohmrie iyf lusiavily anii:lc»rj;a:rii.i:al][y ccni,taini]rial:<£:d soils, decreased si.!E;njiricantl.y,, th.i:: e niiiriate'd volume oif moderatelyi;:c]ntajrninaJte<3i •is.cnl has quadrupled since; llie R.OK> was signed.

AR3025U9

This; increased, volume and depth of moderately contajrnlna.te<3: uusaturated and saturatedcontaminated soils si,E;nifica.;niJy complicates handling and construction, issues associated 'wiithimplementation of those portions of the: ROD, For example ;

« Ptiior to excavation, saturated soils 'would need. to tie: dewatered ito fadlkaiemovement of velude.s; a.nd equipwienLt. Efo'wever, j2;iven, Utie proximity 1:0 HIE:T'ulpehock'en C'n°:ek. and ttie shallow depth of the watis:r table, it would lie extremelydifficult i:o de'water th.e soils; since water could How back into excavation areas irnorequickly then it could be' removed. Under oitie set of assumptions; irejaiardiing tlieability ito remove water from Hie soils, as irnuch i s. !H) n:ii],li.oni giEillon;^ of waste w-aterc<3HLild lie: ja;iE:iMj:[U;ite<Jl. Tliis water would then need to be treated a:rid disposed ofappropriately. It is unlikely thai the e?dsthig ground water ]:nH:ripi a;nd t:n:at syjsteincould i3K:comjn,i;«].iaite such flows. .

11 JE3iecause oi: the: tremendous volume o;f souls (i3ip]:iri;>;(,in:ial:f2: KJ-.COQ l][uicK:-],oads) ajrid,con;s;itnicticni materials being; broui[|]til l:o tJ:ie Site ,, it: its e:n:pns?c:l« l that the elevation ofttie Site 'would imrreasc by al: least 1.5-20 fr:el: overall ai:id up to 30-40 feet in places.The Union C'ana.1 and adjacent ajre:as would most Mtely need ito be filled in and the:Lock: dismantled,

• To facilitate excavation of titic saturaijB(3. soils,, 1['u.]lp«:]ti(]'C.kcti 't i'BBlc a:ru3, Vimn Cai:ialwould «N£«td. to he: ]re--roi[it :icl ixir sev^iral years;. To do so would crea.te a ,s;:ij»nificEiintchaL[] :;njj:e in han.d]:inj;; the volume of ¥/a.itei' and in uiainiaininE; ('LOCK! storage a.jrit3.control. Tiil|x;hoeken Ciw&k onlcl iBvenuially foe resto:nxl hut il: iis unlikely that the€!anal co'iilkl he restored ito iits c:urrem slate due to the :5i:E;ni]:icam mediae at;, on of tiltSite topofjirapliy .jsivco tlms; ' c>lij[tn<£: of ;s;oils foei:ng bnHJiglmt on-isiite,.

A significant volume of dean sioiiL, 'wbsn bEicldiillccl iiri tliHSi :sa,tnjrated. xom: a:fi:er the:excavation, would becionie contaminated, by the ground water.

in summary, ncdf:r;n:E:ly conmn.iiUited unsaturaled soils and saturated sc ils do not appearito 1>B [jrijrn,i3Lty .sources of. arsenk; to the: ground 'H/a.itBi- md in, iJtu: 'BViEJiit: ttiat itlwjy ar'E: lea.i::lu:n]3;arsenic, the ]:»t >pH[>sB<jL ]p«uri].]pi an.cl tirBa.it ;s;ysl:e:in will ca.pu.iriE: tlie arsenic iiriijEirEidnja; ;3fwa.y (icnn th.<=:Site,, Further, significant ijrn|)le:inen.tal:'i].it r issins:,s arc: a,i5:ioc:i;3.;tedi with e;(.<::,avi3ition of saturatedsoils, particularly HI lii hit of U:ie i]iK:rEja:se:d voluiBB an.d depth of the contaminated S

The estimated volume of orijiaLHJically cnoniajCHJlnaJtBd. soilis. d.cx:rE:ase<3l fnm !i,(5W to 4,100•cwibiii:: yajrrilsi ("t:y"') d.uB (o tins: iinc 'i as-EKJl !sain|)],ii]i]Ej wh\i:h pro' id«s ;ai more reclined e,stiin,i3;teandy'or d.iiB l:o natinraJ! biode^radatlori pnxiBssBS v/itiich mny haive induced IcvBls of (]'][ja;anicco]rit3[rnin;3Ln.ts in. soil O-VBI: tiutn,«£:. As a; result of tins: ]:>assia|];<;: of the Phase IVP L-aincl :Di;;5ipo;5al:Rest:r:lct::i(M[is ("LDRii"), a]:>p'iro.«iLniEili::.l>' 211QO <;y of ars-enk i::oiritaj[[]JLtia.i[Bd. soil require i::t :an:ne:nlfor the reiBOval of organic conitamiinani^, Given tlie induct ion in tlie volomie of or[;aiiical]lycontajrn.iLna,tE:<3l soil requiring treatment,, it: would he more efficient to excavate these; soils, for

Ati302550

off-site treatment (LoW"te:mi][>eratLirB thermal desorption) rallier (ham l:o |)ire--treat them oiHite.Organically coouwniina'tBd soils exceeding; PTLa but not irequ ii-ing treatment iinderr HIB PhaseIV LDRs,, will be excavated in accordance with, tine ROD for OU-3 and disposed at an off-site landfill.

IV. WliS ClfllPTJIOlSf OF THE NEW M;TERNATi;VE

lj[i coiuskleicaitioni of iJtiB new information since the 'ROD for OU-3 was signed, EPA,P. AIHEiP and. 'liVLPSCr have developed an Alternative !Rernedy foir Hie siatiurausd soils,moderately contaminated nnsatmated :soi.!ls, amd. or^anicgLllly [;o[]taininai«:;d nj[isal]LLrELte:i:l soiJLs.

rri:iB /alternative ReTin ;l> iinclludEis:

* ]E;:i:ca, rat:i(]iiri and olffi-sintB tirejitmEinit ELIIH:! 'Clis?poswil oi' l]Lis:.a 'ily coirit jrnln itedl i.injiatinratEidsoils, ;uid <:n-E;n:rm:;:Ll]y ictoitit jrnin Lted iLiiis;;aLtiJL:r;aLtei:l :soiils;

» 1:lxeav;3iti.om of oil-sito: ]cnode::n3Jtel.y co:nt SLininEiie l iiirisainratsi'd soils and consolidation

("onstnicliom of n clieam, 2-lfoot soil. ci:tve::r ova1 nru>[leiratE:ly conl rnlnatBd soils. .

A& -vwiithi ithiCi 1EU1D for OU-3, htxmly i:oi]Uimm\\®:\ uiisal:LiratEstl s(3iil.ii v/ilJl 1t«s B3cc^ivi3iitB<ii \u\iil:iri3.:ns]:K)rt:ed. olT-sitEj ibr tiiEtahrniiitn. (as necessary) and disposal , T'tic tre^Ltntient inelJio^ls \u\il<:irit«::cia will toe dk:te::trnin<!d by tilMj specific ]f«!i:nriii :['i;:i:|iJLirerti<:riiJi of tJriE; selected i:li.s];«)«aJi facilityi3Lii.d :s.hji][l meet allL !ElL(!!]Et.k nBquirBmcBtJi.. ]f;ii)UJiti.onL will be: Khe: ]:n-inrun:>' method of treatwieniiLuse l on the affected arsenic-cnntarninaited soilsi, aJltlii'OiJijgh itrcattni<E:nt for removal of organiccontaminants i:; anticipated for isonne oli these =>oi.ls. Siniiilarly,. or[;;3J[U.c;allly co:nt3LniL:iiiii3Lte<JLu.:cisa.i:ujra.itB(jL is.oi.lts wl\ b® <2:xc ; at<Esd. for ol[]:-s.:il«: tris:al]cn,e:nt: (as nn cssssary) amd {Ibpoisal.

Th.12: «t:«c,i3Lvaiti.oi]L oi' tibiB coicit jtnln Lted :s.oiJls \v'iil rBquiii : die: teinp-orary diveiiisiion of die'Uriiom Clanwil ijrito tliws: I\il]E«:tocH:kB]]L.Cn!!'Bl(: This temporary diversion '(i[ip l:o l 'o ya\r&) i:s ncn,iE:;(pei::te<:l to ipBrnrun^Esniitly :tnii|jiict thus: Union. Canal and Lock nor itlie I'ulpBhockeni <; ee:'k,, 'ric«:heavily aiiKl organically contaiiciijriatiE d soil:; are locmied primarily on, lJ:u: Site, with severalareas inrunBdiately adjjaceirit tc» itlie lfni<]>:n QnuiL Ome oif-'Sit : excavation area is loc;ai:iE>dopp(3ns;:iiii2t Klie noirttie^ist corn<E:r of \l\ii Sil:e (1[<]»:[tne::r ]E*r ;luj::t.iion . rssa,),, ;3idjiacei]it to FairLaBBL 'iEiiiPLie and. t:tie: TiJil]>E:liocken Cn:«{k. ]Ei :c:a: ai:ic»:n (]i this area, may be limited 'by ito proximityito the CrBBk md thus: F'iaiirlaJciE: .A,\rE;i]HLie b -klgB crois ing. Jl olT-sit e; i£:jECJ3i-va.itio:n, arBius shall beimmediately hwiclcfillliBd. aictd restored to their original ;e;rade or to a gnawl«: ccunnii'EinjiULraite: wilJtitJ:us si].:nrcnindiiijE;s ans is. !hnB <!:x<: Lva,tioti. oi' huiavil)' coiiriuaLtniinuaitc l is««Jls; and organicallycondtiiniouutBd soilsi will 'begki dming tine laniirunin of IS'W atnd oontijciujs ibr appiroxiJciMLtely dgh.it

R ':t Hi ? i:! ciI i tj iji <:. ui - 1

:L.:LOff-site moderately contaminated uiifla.nnra.ijBd. soils virould foe excavistted to the water

table and brought back on-site. The excavatiiom arctiisi would 'be backfilled, with lightlycontaLmihiELted or clBaii soil, covered with two feet of clean soil, and restored.. 'Once oiri-site,,Tnoderately contaminated soils 'wonJkl be placed in former excavation areas (locations; of theforrmer lagoons or iueas of. heavily or organically contaminated uusauirated soils), :re:;E;rad.ed,;3i:nd covered with two Ibet of clean soil.

.As described. iin llie ROD for OU-3, lightly cofiULniiniated soils om- and off- she 'would becovered with nvo fast of clean soil and n;vegetated, HIB soil! coveir will be monitored andmaintained to proiteci: against subsidence,, erosion. a.irid other faci:ois.( which iiiEiy UhirBaUKii itsintegrity, and. will |]NE: :t'(=:st(]'ite:d as Tiec s Lr on «, periodic Ibasi.s. Dm\. rBSWcikrtJioiris wOlcontinue to be required 'for on-aod. off-site: ajcejaLs; vw\m& i:onitarni::nat'E;(il soilis. rei ruiin,.

TliDB ROD :Ebr QV--3 rKcjuiircs U:ie excaivaition. oi' setiiinEimts that BXCBcd thus: <£:?Ec;3LVjii:io[icriteria fin1 nriorteiately coiu:Einriij:iai:«scl soiils if nhey are: acljaceni. to soiil trmiediatioTi arBas.iSSecltoeiiiii: SiSLtnp'lBs shall bB collected iroiti. tJt-iB lJirn.on; Cam\ ibllowijrij'' i.its 'tBi:ri]>orary (jli\ri£:rs;i(3>][iito supplement ejdsilng »clii:tneii.i: data ito (ieteirnniiu: the extBiit,, if any, of contaminatedisedimients which i-EX][iLdri=: exca'vaKioii,

iDurini; tiie desij n oi'iht: A\\&nin\;\vv Ilsmtxty, an ev^iluialiion will l>=: ;[)e]rf(]Tiiiecl todetermine 'H/hBl'tieir1 oxklizint; ajj;iBiu:s; or other chemicals could be used ito increase thedissolution of arsenic: iTiinn tins: soils into thus: gi'ouin.cl wai^Br. A:i\ operations and Tiiaintenan.ce(C»i.!P[) plIiEin shall also he <J;(£:ve;io]:K:(3i durai|j ttie d.esi#;n phasw:,, isnn:l will kncludtf idetaiJs icn1iiH:'Tij[toriii;E; soiils., sediments, surface 'water iu\ii gmmd water m «VEili[iai3£: itlws: i;:fife<:ti\'Bnn£:ss oftJtu: rBiincdy, Discuswiioiiii art; cutrently heing itielxl hertv/^j'Eini EPA^ PAJXP, WLP§G,t ibsacurrent Siite owiriBr,. iSind lo::al officials \.o determine if ithe: bBnericial rE:-ii!»e of a portion of theSite cam bB incorporated into ttie: lon^-terui pliauis for :niiEii]:ita]LnJLng die Site,

The Alternative 'Remedy and p:reviou.s remedial actions will be evaluated dining c^ich.l:ri\r'B Year KB view, llie KJCI: Fiive 'fear RBVIBW of ith.«: SiitB shall \K>. ][H*E:|>ared. l:»y Nswch,.2000. If iit i:s <3leti2::nrninii£:d Utiat aisei ic iw (>itli.«::r coiustiiuBnts art; not successfully contained bythe soil coveir and pump and treat system, then irnodificaicicms and/or other remedies, will beevaluated and the: appropriate actions implemented.

V. EVALUATtt-ON OF ALTERNATFVES

Tlie ]?t.OI) ,ReTti :icl] :mi the: Alt^rriatiive KjBinB<ily ium: I>S>BHL e ralliuatecj: according io ithe: ninecriteria in die NCP 40 C.F.R. 30D..430(e)(9) as; set forth in, "Gtiidance Ibr Co:rid:iLici:irigRe:rnn»diial Iniveisitigatioiis and Feasibility Studies Under CERCLA1" (EPA, Ocio'b«T 1988), andUA Guide to Preparing Supwjlmd Proposed Piam, Records qfDedswnff and Other RemedySdtct.ion Decision Doammis" (EPA. 540-R-91KI31, July 1.999),. litiese1 rum criteria can I>B(iLirtJ:iBr cal:e[K»ri;?:iE:t] into three groups.: t]itn£:,s;hold. critciria, primary balancing criteria,, andmodifying criteria, as follows:

,0 D ';[ fii 71:; c oi^li I i J U L iJ 'Ji i:.

Overall protection of Itiutnan health, and tins: environmentCompliance: wii:h applicable air relevant and appropriate irequiirEiniLenits

Loiiig-terai effectiveness;]Red.iiicuon of toxicity, mobility or voknxie through treatmentShO'irt-fcBnn effectiveness.Iniplementabilily

] .Acceptance

TlHWft evaluation ciriiteiriia ns:lajtB directl] 1 l:o requirements in Section 121 of CI'ftRC'LA., A2D^S.C. •§ 9621. Threshold criteria must tie: satisfied iin. order ibr a, remedy to tie; eligible 1:oirselection. Prinnairy ba,][,any:;iri[!, ctiteiriia ISLIIS: niSEsdi 1:0 w.\$\ niEijor triaide-oifs bci wcuBiii alternatives.j\cE:ept;jj[u:e by iJtie StaitB and C!omnriu.:nity ajre mo liiE ing ct il jrla i'onnalliy tiOTiisi leirecl lailitBi:public conini<::ni is received on die; Proposed Flan. A. discussion of each criterion relative tobod), tltc ori kmd RO\~.) E.vmvay and. iJtie /Llle:mat.;ive: ]ftj;::nu::[l>r is presEninteiJl bf:l.ow.

,, Ovwn\U ]E']:<:»t (:i:i<:tni ol' 1:1 ujiuajn 'Heal.tki andithc lilnvii

Both the; ][\£}]D Re.nm\y and /!dle:matjive: ]E!.<£::n]ns:'d>r ate eKpotted tc» ai<::hieve: overaJlprotection of human healJth i3i:nd the; envinminent by ttie fol.lc 'uij;,:

<> 1'jccavaiti.on, l:r<; atrcM: [it, aj[id. (]>:[]f-site: disposal of heavily contaminated. uLn ;],tu,]r'a,tE;(jisioiils;

iinj3«JtujcaiB(3. soib followcacl byconsolidation on-siite;

9 InstaJlljitioni of a. i:wO"lboit cn 'Bi: of dean s;oi.l o\p<E:r all lii[;l:Ltly (xi it LtninuaLted soiils; and,

" Re:ni,e:diiat,iK)]ri of coiriULiiiinaied swErdiLinienKs ;3.«:x:oir(Jiini;E; to cdtexia ISLIKJI inn tliKxiLs fc»r heavilarid nruxleirately con.i:anriijciai)Esd soiils wbm adjacent to soil ranuediatkici areas.

Tltie ROD lEIjEiiriBiJLy wo-uld iurthEtr be 'expected, to achieve overall protection of humanhealth and die e iviroimineot by;.

" l:ix.cav;3itiion, i:ri£:ai]HH£:ni:, jjud. olif-siit : di!i]>c)saJi of heavily contaminated isaitin'ated soils;

AR302553

« Excavation of moderately c:o:nl:aminated saturated mis, followed by consolidation, on-site under an. i:rnperineable cap; and.,

11 Bioremediatiion and off-site disposal of organically contaminated soils..

Tlie Alternative lEtemedy i;s expected to achieve overall protection. of human health aridtlie environment by::

11 Treatment of all saturated soils via the: ground 'urater pinup and. i;re;ait system;

* Ex.aaiva.tiom and off-site treatment (a,s; irequli^d) of ' organically contaminated is.oi.ils; and

•• Installation, of a two-fool: cover of clean soil over all moderately contaminateduiL=atu:ratf:d soils;.

HIE: extent of .siaturEited heavily contaminated soils; has decreased by approximately 90%since continual! pumping; of ground water began iin. April 1.9913. The extraction of .[[roundwater lias; lowered nhe: warn* table enabling the excavation of additional lieaiviily contaminatedsoiils that are cunreintly unsamirated. Pumping of ilu: .ground waiter will continue liiroughoutthus: e«cava.ition. acitiviiiies to n^taini the lower water table and maximize Hie anri(3'unnt ofuntis-ituiiiaitecl isoil that may bB 'excavated,.

Iihe Llt<;itiiai:i\'iE: l^snriecly utilixBs thug: :nannral ifhishlng oi: jsirounujl WAIM l:tH"HUj!Jt:i thesaturated soils, and I'he infiltration of precipitation l:tiroi.ij»lt:i tlin=: soil cover and ttie moderatelycontaminated niisalxirated soil:; thereby allowing an;enJic ito leach :from coritun.i .cci:! -oils andmijEjratis; via. j3;t'ou.:ri(jl '« al:er to ttie JSII'OULIKJI wwsr extraction WBlils. Tin;: ajrseiriic (an<:l odie::rc:(]>:nt Lminants)' ^ill tJ:ten !>E: withdia'wn InMii. i:tn; ai:|niif ::r' and pumped to i:he oTi-sit : ;j;rni.in.<:lwater treatment s;ysi:emi ' 'liiere il: wiill I>E: coiri[:entrai:iE:d ijri ;ai :([I!. nou-lijuanlous, ars^iUK-rich,5iIiJ.dj3;iE: ani:l disposed of at: m ofi:-;sdti;: secure landfltll. HINE: .(iVlitBniJaiti%r'B .I5:emedty willl entaxeiaini:! !tia.!si:em ttie oveirsdl r'Eimo' aJl of ignisuKiiJic: lxi:nn the Site soils. During tlinE: Remedial De:s;:if>n oftins: . Lliternati 'B Remedy, an eviailuatioiri w:illl be peiforaied ito (JleK irriijrie v liettier 0';i:idi;E;:imjE;m<r.[[\s <]>;[' (Mlii;:[' chcniica];: cou.Jd I>E; nise^l to inct' L E: itlic: dissolution of arsenic; fiotn the: soilsinto tJt:u! [ground v/iatei and decrease the: i3.in.ou.nl: of time required to remediate die soil:: andground wata*.

The ROD K.e:mied,y involves greater disturbance of contaminated material, ilierebycreating lueaitei potential irisiks i\ur\n\i rercied;/ implementation. l:;xca.vatini;E; .SLaiiuii-ated soiilii inthe vicinity of the Tujlpelicclceii Gcwstit. ajrul Ihuim Caoatl rEtijjeis sevetal (x icemsi ire]s;ar(i.ini;E; tJ:iBKile^se of contain iLnajit::?, (jliirijrijj; ireniecliiiEilion. Fiirst and Ibrennost, :3>() million j];;ail]k)KL5; of 'waisi:eAvaitBi: 'with i2:le\rati;:d levels; of contajrniiL3LntSi ajrui, sediments could be generated, (Jkirijrig; t:lieexcavation o:f Hie sainrated soilis. Infiltrating ground water would be a sigmlicant concernduroughoin: ithe: e:rit:irB c;(,c:av';3Ltiion of the saturated soils. Handling and treating tliis extensivewiistis: istnsiam, esipeciaLly dniring tlms: whiter and during other periods of inclement weather.wiK\\d cn£:at€ iriuine:rou.;s. opportunities for uiu:o:ntn:>IJ:i£!cl rBleaswis tha.it could impact belli human

AR30255J*

14

health and the enviroininent The re-ionting of Utie TulpEihockfln Cmt\i could also cieateuignillcant impacts. to the environment, ' specia ly during periods of lElocding .,

CUT-site treatment of. organically contaminated soils, will 'be: mine protective than on-sii:etreatment sknce the soils can be removed fioin the Ske moire: quickly and will, require lesshandling l>y workers,

The ROD R.eim.edy mil the; JtEirnative Remedy are both protticlivc oi' human health and.line envkronrnienl:. The: JternatiYEs Remedy relies upon tlie. capture; oif arsenic 1frorn thesaturated mil the nicderately contaminated :s«)ils vm ground water extraction 'whereas tin;: ROD]E!.einedy relies upon the: e;«:c:aval:ion ol salnral:< d stMl:= ai'id Hit: installation oif tins; itnpetnieaiblecap. l>Lie \.o thiiE: isii;ni1fioi3Lti.i: potential irniriactsi ito i,he. Tui ieliotikeii C:ireek,!( wei:laBEl!i,, c IfniotiCanal, ami Hie Lo::k , th.e cli.ilfioiLiltie:: associated v/itJri th<E: i:le' rat:erLng and e?;cavai:io:n oil -thesat]Lirat:<E:tl. soils,, and tin;: success 10 ±w of tine gionnd water e::K:ijra.cti.onL and treatment iysie:rn.,Utie Jl E;rna,ti\re l^emedy a]:r[ie Lrs. suipeiriior 1.0 itlins: ROD tittoimiy *w\mi e^'-EiluLEitimia; the; protectionoi"!:ii]m;m h.e:allih and \hs environment,

B. l[!<cii][i][»IJLaj[ic ! vrith ,AL]p>plii<c:altille or

Both thus: 'ROD Rerne l;,! mil iihe Lk'E:ni;3Lti: e Re::tm«E:dy 'WM ulnd coimply '«nth, all statistfedEsral LR. J j,, ]Elcit]:i ireim^wclijKs; 'wcculifd need. 1:0 meet applicable 'petmits as&ociiated -w iitln ttie:transpo:ttatit3n, tiisiatJtneiit, and 'disposal oi' l]iea\rily co:[itaLminatte:i:l soiJis mw:ler RGEtA.. TlrieA'ltcmalive JELemedy woulicl mil to addn:;?:? additional n:<nine:m.i=:nt:. a:5:;o;:iai:Eid wiui tliys: off-i

ent of n!

'[k>\;\\ i''::in£:d LE:S woukl rE q ii.irt:: !;i:t iam E:n ::[oac hrricnt | :' ari.o«iisi ccHiusitrLicnion. •p nEicnJits (Tom PADltiP,, IjEibancm Go. , a.irid. Jfaeksoiti I'ovy nship1 l>£:caui E; oi:potetitiial. knpaets on Utie IJ'iuon ClariEil, and T'ulpehodken CrE»:k. .l-lwwi/ jveir,, b(!<:a,iuse the RODRemedy emails; gnstaleT re-routhig of. the: Cmte ai\d possible ahajridnnarnent: iyl' Ur«: ClajEial andLock, si,]s;niric:ajrit,]iy more |>s:rtniittin[;, i.is.!Sijies a:Ai ariise; (riiae to the historic viailne of title: Locka:nd ("aniatl an cl 'habitat: loss of the Ciinall In aidditioti., :rnocl:Lnc:ai:io[is or new permits ni.JL[;l:tt he:necessary for trEsattnKEinl: of iwa.si:e 'winter i;e:]neratE;(3. duiriiEiji; lilw: dew;3Pteriiij!; iy[ tl:«; saLtuifjaited isoilsi.'Thus, ttie: JttTnative HLencie ly i.:s. pfeferahle w'iih tt;::s;pect t(]> ([

TI LE: follio ijriii, ijs; a. list wf /skJlA Ls idi2:[H:i1:ie:«:l by EPA. ajrid PABE3E1::

Pennsylvania.'' Cleiui Streams Law, 35 P..S. § 691., 3 (ralatinig to discharge of sewage aindusitria.! waMes); 691.401-.W2; 691.501; (5.91.503; 691J801.;

2S FA Cod*: §§ 16.2 1.-16.23, 16.32O3, 16.51 and I &..W2 - relating; to waler quality toxicsmanagement,

AR302555

25 PA Code §§ 923, 92,5, 92.7, 92.9, 92,.81 -• National Pollutant: Kscliaige Ellimdnation System. -Pennsylvania Direct Discharge Standards; §jj 9:3.1, 9:1.f>, 93.6, 93.7, 93.ft - relating to protected•wateir uses; §§ 102.4-102.12, 102,22-31 • relating to general erosion and sedimentation control;§§ 123.1, 123.2 •• relating to lugirtive missions; §§ I-M, §§ 26L, §§ 263;

Pennsylvania's Solid Waste Management Act, 35 P..S. 6()IB.K):i et !3<X[. promulgatedregulations under Tide 25, Chapter 262,, Subchapusr 13,, §§ 262a.20-2(52a.23; Chapter 265.,SuJbcltiaptex I., §§ 265.250-2.65.258;

Pennsylvania's Dam Safety and Einciroa-chnrtenit Ac;t:i 12 R!3, §§ 693.6(a), 6<O.6(d)>, 693.7(a),693,9,, 693.13,, 693.14 and proniulgated reflations under Title 2:5, Chapter 105, §§ 105.113 (d),105..231-245, and 105.451;

P'ennsiylvaniia's Storm Watfa-Mkriajgeinient Act, 32 P.S. §§ 680.5 and 680.13:;

Permsiylvania's Hood Plain, Managernerit Act, T2 P.S. § 679.302;

40 C.F.R. ij 122.28 - General Permits; (applicable to State National Pollutant DischargeElimination, System, ( NPD£S) pfO{>nMTis);,

'10 C.F.R. § 50.6 - National Wniajry and Secondary Ambient Air Quality Standards ibrParticLilate Matter;

40 C..F.R. Subpant B §§ 2:62.2.0».26:2.23.; Subpart C §§ 2'62.30-.262.34 ; 26:2.40 - StandardsApplicable to GtonenaLtorii of Hia^ardoms. V\/a.st(:-rrii[i£: Mkriifest,, Jr'i'Es-'I'riajujp'ortalion RssquirKiMntK;Recorcikeepins;;

40 C.P.R. Subpart G jj 264.114 •• Closure Requirements; Ibr Disposal or DKcontEimdnaJtion oflEiquIprneot., Stiruc:turE:s and Soils;

49 C.F.R. Subpart C §§ 1T2.201-..205; Subpajrl: D §-§ 172 ..301-.304; .308, .312,.324V 331-.3-32,..334,..3.36,.:3i38; Subpart E §§ I72.400;1.406- 407, .431; Subpart !E! §§172.502,.MO,.,S:i4,.5116,. !> 19, ,!5.!!3; Subpart G §§ 172.60: .604 •- Haziaj'dous Materials TaJblc,, Special Provision:;,Hazardous Materials C'oinmunicatioiiSs Enicrgigsncy Response Infonrnintion, and IraiiiingRequirernients;

49 C.F..R. Subpa:rt E §§ 173 22, ,24, ,233; - Shi ppers General Reqi'LiiireoiciTtii fo;r Shipments andPackages. (on-Jihe aKtiion on\y)\

49 C.F.R. Subpart A. §§ 174.9, .14,, .20; Subpajrl: B §§ 174.24,. .26,. .50; Subpart C §§ 174.37,.59:, Subpart I §§ 174.680 •• Carriage By Rail, (onniite a:;tion only);

49 C.F.R. Subpart A §§ 1.77.801-.802,, .804, .817, .823; Subpart B §§ 1177,823, .841- Carria.ge- ByPublic Highway (on-siile action only);

IIK302S5E.

16

16 U.S.C. Chapter 661 - Fish, and Wildlife Cooirddnaition Act.

The folJknvkig, are Jo Be 'Considered Standards:

Executive Order 11L990 - Protection of Wetlands;

Executive Order 1.1988 - l:edeiraJi Floodplains Management R.eBuilaticuris; and

Ltlclitiotially,, Pennnsylivania has asserted that The Land Recycling and lEtfivironurnarLlalRemediation Standards Act, 35 P.S. |j 60261011 <K|, wi (Act 2) is an JL ft lEbrthis remedy.EP'A has determined thai .Act 2 does, not, on the facts and circumstances of this, remedy., imposeany requirements more stringent than ttie federal standard, ]tlo'wever, E-FA haw determined, that.Act 2's proiTiiill gated regulations Ibuirid. at 25 PA. tloide 'C;'ha|»l;eT' 2%{)v §§ :2:ii0.4G4 ajrid."2!>0.702i(b)(3)(ii) s;h,aJll be ]rb « Considered stajruLairds ibr thiis ireirne :ty ito ensure ]fM'oi:ectiv<:::rie!js of]:ml:»iic health iMid welfare mil the isn

C, l.-)]'n!E;-l'E:n:ti li-ITeciTi-cricjis i

Tl:ie ROD' md ^Vllteirnallvis: lELeirtEidies pr(3 ri.d'£; Ibr 'lon - sinrn, eiElceci^yiKnusi'Sis equially mihr£::i]>;;ci. 1:0 itic heavily and organically i::i[)ntarriii:[ial :d tj [isai:Lirai;i: l soils bo::au.5.e both iLti\Fol,A e1:[ :alin.< iil: (fixauon of arsenic ajrid ]:";:rrn.;:Lt]c:rit destruction, of line orj unc: C(:>m.p(Mn"Kl!i) and off-isiitu: disposal. 'l3-ol:h rennedieis. aJiso iiKiliadis; ttie soiil cover, 'which provides long-term protection

Undeir \xi\h ihv ROD md .Mieniftitive l eiinedie:! , lo'iig-ttinn nsta ai s .ass(]<:iatiE;d willi tline;a,]t«eirii.c; in, the soilis, si:cic«: rticitaLs. cajrun;»t Ix: dest]royc :l. line iin[3 :nrni;:iEtt)le ca.p :requirtfd 1:iy ilrw;ROD RiMrnn^dy would ireduce tl: : arniou til of arsenic n:a<:hin[; line jrfOLincl WEiier ILEI the: .liC'Ti:ternci but would not significantly re(],uc«: iJtie mass of arsenic ait the; ;SJiit« iyw iJtint; sinn: : iniostof the arsenic would rsiinaijn Lnwleir ilie cap. finilnennore „ clean, soiils used as tjjw::!kJ:illl in thesaturated :ior. v/cuj.ld. become cooiaxninajbtti by cotiuc;! wilJti the ground water.

I'tic: LliternnaLtii've lEtamnediy wo\M h«: irncms: i2:ifeciti.\re \n iitiu IxHiLg-leirrn iJtian iLlns: IRjQlD l^enriedi:Ebr iscr eiral ti£tas(]i:Eis.. First,, itlie soil cover o's er [Eodenilely con.tEiinij[ial :d soils v^ouild, aJlloAV foriiillltratiion «o1f prec;i]:>it L'tiion i:turoiLij!;!h the isoill, i 'tntvidiing 131 i[n( :hajrii:i]:n by which nmnw can be:c;aplured by ttie ground 'wa.ter pinnqp and treat sysiteni and pemiiuriemly retno%'e(3l firorai. ibe Site.Second, because saturated :s«»iJlsi 'wo-uld :not be excHVEilM,, cleajci iiiuBiteituELl would not becomeeomtanii:naied aliteir hanclcfiilling. Lastly, liLiluns use of ibe situ:! wcanald be: n«o:re: ftsjd'bk beeausetin:; lk)\ver el ivjaitiion 'w cniH'Cl p'lr'civiide: moire optiC'iris :r«:gajr(3.in[!E; thus: beneficial. re-u.:se of die Sii s:and because tln<£: C'.\m}. '.mil Lock 'would ir' naLiiii iiti place..

A& 'w'nh tins: ROD Ewi\\tN\y, it is :ri ;:o]3;nJLj:ed[ tha.t thrfstiis: irnay 1)«: !»o:mie loiig-iLerin :tisl;sa:i!ioc:i,;3Ltei:l with leianninja; aLrs :iiJ[i:;H::ontarni:ruii:ed malarial on.-sii:e mndeir Urie /LllJSiiiciiini^'is: l^niietdlysince metals cann.c»l: l>si desuoyed,, IHEtnvever, Hie airsenic wmlil I>E; :ri;::rnLO\'e(]. Ifroirn. ilru:

lc:

17

contaminated soiils to thus: exiJEsnt practicable by ithe gi-oiurid, w.aie:r p'Uiitp ajrid treat system.Proper disposal of the ground wateir treatment residuals;, and inonitoring, eo;rilauirnien,i: andtreatment of the impacted ground water would provide ten1 appropriate lonijEj-teirmmanagement, Thus, because mow arsenic would ultimately leave Uhe Sidle under the,riJitt:rnaitive Reniedy, iit provides greater long-tetm effectiveness an,d permanence.Additionally, eontanu.:naited soils 'woulid he covered and desxl restrictions placed o;ri those aiea s.to control liutiu'e compel: with soils;. Th<E: ic>\iE:naLll i:iine fnajnus: to restonE: itlust ground 'w/a.iter is note :po::te<]l itt]' l>ss .siiijiuiikiantly difibnEini: :[b:r tfie 1?EO1!]' aju3! >Ui:emai:i\'e Remedie'S,,

D, .R.ei[liLidtk»o mil' Toxidty, Mohiiliity, or Volunne Thi-ongln 1'ir'ea.itntK itnt

Eo\h the ROD mil Alternative: termed ks :r'edun;:e ihsa itoxicity, nriobOicy, anw:l volumie ofcan;:arrii::uin[s in 'ihe heavily a.:nd orj;iuiically c:c>:nl Lniiii tt< :l ;i]:;3.[u.rirtc:(]! soils liluroiLigh chemicaltKatmenl., 'UrAr both alternative,*, ajrsenic v/iouild. be: immobilized im utic1 nricusnt itugliil]contaminated soil!* ihrouij»h (i3c;3iti;ion airuj! the toxicity c»C orjE;aiiit:aJll>r c:i[)n[ta]:rii[riai:ed soils wouldhe ]:edii.i:iE;d vi« U

UiridiEM' l tie 1FS.(J][ Remedy, i:he nnobUiiry d' arsenic; in the saturated soiils Einntl n:iocleraij£:l>'contaminated; unjsa.itn.:r'i3itei:l ,s;oils \m\i\il 1>K decreased by pl;iaic:enienl ujrui.«:i' IJtie kn.permea.fole cap,.By bacikfillliiijj: tlie satuia.ted zoirie wi\h clean fill it i:s wry liJkely tliat tfijs fil.il 'W/i:mkl l>E :oirniccintamiiriatiS d by [;o:nt£ic:t viitlii ja;rwiJLH«l 'wiitssr. Thus, the volume of cootainlnaited soils underllt-it: ROD K.<s:niL'K(3!y would actually increase.

Tins; ,!\literttative RjEitntuJly does nioi: iredimce t:tie toxiciry iyf U:ie [ Jtmaii ini; soiils, however,, itdees inc;nE:ase tliie mobility (]f con.tai'iriijriants im like soils hy alloiviii;;; tlinEiiiii no migrate into HiejE;i'C)ULHi:l Avaiter, thus becoming s[)ajrt of, aj:td controlled by,, ithe ovendl (iicnirid w,aite:r reniecly.Ilu: 'K3(:itr.aci5s;d. conita]:niLnajrH ^ wimld lie ii:rHjrii.ohilii:!iKd. JLII am insoluble non- hazardous &\ii.dgvj];i£!n.«:raitei:l by Khe grouiiicl w&iw Ur itrrient sysUEMiit. Ullnnately,, thuss c:ontroi[lei:l incrEiase ijrimofoillity |>]ri:ivikl«::s; fiw gmi\&r :r«mov;aLl of arsenic: licnm ulie Siusi. Tins: volume; of contaminatedsoiils would, be: reduced under the ^Jternaitive HLennedy as tlms: iaLt'isi nii:: leaves thus: Site ilirougli'c;a];tHjLH!t, coniitaimnent, anncl I3re;ai{i:ru:irit ijri the jE[rouind ater ]:uurnp wild uiswii: system. Tliuis., U:ieROD ajrid Jteniaiivt: Ris nus ly arEr iKtjiral. im reduction in. toxitity . I'tie /Llternative l ernecl}/'iriiore eflecitiive ily irecluc Eis volume tliroujE;h creiaitiirient whiltt allowing a limited, but co;rii:rollledincreas-E: in mobility.

E, Shnirt-tcnm lEL/rfecrl.iveniess

TlinEJ ROD ajrid . JiJE:rnaiti;y c ]Etjs:inuE«lii'Ks are effective im i:he short-tcirn tJ:LiX)u:;E;h itlws:iKxcjaviaitioni of die heavily contamniattEid iJi:nsal]Lirai:(2:d soiils. Thus! ROD Remedy is less effectivein the short imm nlmi the AJternative Remedy in iregani to tine organically coniaininal d soilsbecause lit is expected tliiat o:fiF»sitet itiieaimeiit oftihese soils -can be iraipleniented much morequk:ldy. 'The IK.OiD Reirmsi'dy can be implemented within ajri isssitijrnjaitedl fm-ywAY penod. Tliist:ime fr'acrnnE: is iu:cessary for i:he efective biolo.isk:al. treatment of MJLJS cioiritajrnjinanted -w/iithiorganic chemicals and for extemive excavation and baddiilling.

AR3025S8

In the ]E!.OD> Kennedy., consolidation o:E' saturated soilii and inodeniteliy contaminateduiiisatULiated soils; under 'thus: impermeable cap would. qiifcldy reduce any contribution of arsenicto ttie: ground 'water from Iliese soib. However, knpleirn.e:ntaLtk)n of IJtie ROD i-emiedy 'wouldcauses Eiubsitantiiail 'diisitinbarce to the Site, adjacent properties,, die Tulpchooken, Greek, UnionCanal, aud the Lock. As |Meviou.:5ily discussed, excavation and backfilling ij:i the saturatedzone -would require significant dewiELlerinjE; activities and create iriu.irneirous opportunities Ifoiruncontrolled i leasies;, especially iknrnijj; inclement: weatiicx.. Tbe iiEnroutinig of tlius:Tulipdio k.eu Cn:ck could also cwd\£ isi iriiiiii ant i]ii];>a{:l> to this: envirO'nineni, c::s.]peciapericKls of [kxxlnii . ITI ad.di.Kion., dean backfill pliac;cd m the sal]Lirat :d ;:<HIE: v/ould !.il:i::l>'

a.iuEu]> ; = a. rE:!;uill: of ci iirkicrig iin.to conuu:l. wii:h cro'nta

The Llternani 'iE: !Rerrie ly has a \n\\h <LleiE;rE;e (3i slioi't-leirrn eflbttiveaess it)e<:aaise i.itnunLiini;j,i;:=; Khu: extent of excavation, thert by rE;dnciin,g potential risl;;; to /otkEnrs md 'tireMinn.'Liruiy. mil e:!Liji[ na.ites t]-ie nc<=:cl to piace cif:a:n backfill in an area saturated yx/jithconxaiitkiBai^d i!;:r'C»uitd. ai'M. In is expected tliiat U:IE: Mi'tt natjive ]f!.e:rnj:icl>r can. l:e iiniiienriEinte L^ iihin. ai;ip]rcixi:rn,;3iteliy KW® yeiurs, 'I'lieir iicinE:, the: AJtis:i-nati\re tiLeinedy iis si|j;:nii:[iLcantl.y moreis;f:Eii ::ti,A e llian the MJD Rvmidy hi liie slu;)rt-t :ntn,.

MutHiiiKroiJisi iisHLieii are aiisociiaited wiitln itlwst :iinp3leiriE:nta.ti(]':ri oif tli«; HDD Remedy,particularly ith in ispeci to the cxt:avai:ion oi' saturated soils Moist lii nif icaiitly , it would bevi-ry diliiciiU. :u\d ]fK]>itE:nti.i3Lll,y irnpoissiibLe, ito excavate all oi' tltu: saturated soil no bedrock.l>E:E:auL E! ol: the :nj;nifi<:am: ArC'li]:[i]j:: <:»!: A^aJter thtat would bt: f;one]:at:<E I diarin;[; the coinstructiion.HIE: t]:ii<:kniis: si oi' Oie satin:at<Esd. :inm 'swajs. bE:lie 'iE:d. l:o b«: a, I?E:V/ ifeei: thick vybeiri tin;: WM)'Ei.E:n:iE:dy was issued. During Kh.<s: iremeclHEl] design, k m& (ktemii'ficid thai: i:ln;: ntii.ckjriEiss of [lu::satuLraLte^l zoine I'angESJi licnn ibinr' to fifteen, ifoel tilnck., . 1 ;>, iit wmM he: %rerj dlf[]K:u.lt tomaintain 'structural stability in. iJtie emica' atrioin area s due ihii pre!iert:;e of water. Finally, Utielar;E;e volumes of soil to be excavated would be diflicu.lt to manage an,i:l pl.j3uc:e oici-isdte.

BPA acknowledges that it may be extrernely diiEficuilt: w mpknmi ilcte excaLvaLtion of£ialiJLrcil«:d sioiils dovnri to the top of bedrock., Mo'wever, ]&A is :rio>it o];i|[M]«s«ncl to <2:xi:ai'vatini; Utiei].][)|>s:r ifK3'irti(]':n of this; s;3ttuu Liei:l zoirie airul. shall dijrcct the t::S|K]i][isil:>ie fwnk& \.o psr»]nE»d.Jiai : itlw;:soils. i;:n the IbllLowirii; m:inn r. As iJrie e;i:ca.\rEit::ioiri of ltiea.vi.liy Koitii wiiiiuaLte*]! w:>\l appt'CKiches the;z;one of sBLtutnaitecl isoiJl, 'MTJPSGr w\l\ iioimtm® 1:0 ei ca 'isite Utie soiil into die upp ir poirtioiri of tlite:s.atuirat.e»;l zlaiiE: to the extent practical,, 'Bxcaivatioti, activities 'will, not: be; ltia]ite<jl until alto:r itlms:sat].Lrati;:d ;:O[K: is >E:n.c:trati id and parELEilLy cxcavatixl

Title ROD a:nd , LlternaLti; e R.i:::[niE d,:iE;s are equally ii[np],iE:in :ntal>lle mth res]>EJc:l: to heavilyi::orttajm.iina.te<3L iLnjsa,tujraJte(3i soils;. Off-sito: trfsatnitenit of i:»r(;ajrii,c;aLll,y 'CU)]ruajrnJLna,tE:d soik, a!>pr(]po s:d \m]tim the: AJtETnative 'Reirnnssd.; is tnore eajii'l; itnplemLeni d, Utian on.-si.te treaJcn Knitdiu: to thus: ireduced. needi 'Ebf handling, teistinf;,, 'Cl(Msii[[n, ajrid, |3H»inrn.iittin]E; ac;livitiies;.

Hi R 3 OZ 559

Uixler both the R01D .Remedy and Utie Alternative Kennedy, achieving the ground watercleanup goals may not be; technically feasible, even though ithe proposed ground water control.and treatment technologies are highly reliable. U.S. EPA recognizes thai: it is diffiailit itopredict the iLiltijrna.ite concentrations to winch contaminants Ln the ground waiter irnaiy be reduceduntil the extraction iamd itrealiue;rit system have been opeiatnig for sonic time,, Therefore,,ground water quality 'would have to be monitored during tine extraction and treatment pirocessunder either remedy to establish tine viability of l:he selected remedy,,

Even though, lliere are engineering concerns. related to the iLrnplemtentcLtion of the.AJletinative remedy, they are ifar toss complicated than (foe ROD* B.ernedy 'which irequiires; theexcavation of. saturated soils down. to thus: top oif bedrock, Basad on the above,, tine .AlternativeRemedy is; preferred 00 the basis of iinplenienuihility.

U.S. EPA estimated the ROD Remedy would cost: $27,200,000 to iinp-fcmenit (1990).However, actual costs; to ijrn.plernien.1: the F.OiD conl.d a|:f)roi3ich. $35 million wten ad[ju,;stE;(i. foiinflation and I]IE: inci'easEKJl volunie ajrui d\s\ytii c'CsatiiiraiJEui, inc3clerahs;.h ci^nitauiiiriat^xl soil, Kl. isiainiiicipated thsit Utie AiltemEidve ]f!.is::inie£l)f iciould bn implemented wil:h a cosit isavin^s oi' hetv*een$15 inilliion 1:0 $20 niillikm. It shoiikl be noted that off-site' iieatnnent of organicallycontaminated soils: may cost: more thiain. o;ri--s;it:e bionsmediation., but will! reduce the timerequired, to implement: iJrie reiriEKJly l>y 2 to 3 years;. This slight iinaea;s;e in. cost wa&coiuikleracl whim is:,sitijrnaitijri(s llu: t.ola.I cost saving of. the: Ji:ernative Remedy,.

iLis iclis«:u!isioni;s. liave 1t>e<:]ri hekl witjh the 'Couirnioiiwcaitli ol: P'l mis l 'aiiiathe; implementation oiftbE; ROD ajrid ^Jternative Remedies-. Tin: C'oiinnoirn eialiifi oifPennsylvania. ei:»n;c:!Ln:re(], wil:h U:ie fc]te:;rnai:iv«t Kennedy on S :pi:erntbeir ;IO, i£W.

<!]'i:Mji:nse]l ;fc«' an adjacent pxopetty OAViriEir siLibiniiiteti: extensive coinurnents o:ri ihe ]pi'0]>o:se:i:li::h,i3LHj3[e!j to the; re]:ne:dy ajcid nii.i5.eicl nmineroius ic:(3':ru:enris du.:rln|a; the; publiic irneisunig. A sunirnajryo1: th':: comnieintt <\n:\ response:;;. discus!=;::d during the public nieeting ajre: included in this:iResponsiiveness SLn:nrria]:>r. A. point-by-pouit response to their 'written conrunemts jaitis: ailsoincluded im the KespoiisivejiHSistSi Suiturniars' and a copy of their suhmitial ha.s I>i2:en placed in the:^jdmiuistnitive KKKOII:!. C'o»i:ri!jel ]re:prE:sentii:n|3; ithe: a.djacent pircKpeirir^ amm sta.i:e(], i:he>r 'wouldivhlidraw ttielr concunenits pending the successful sale: of the: aclja.i:ent ]pn'0]>E:rt>' to (JienKSp<WLS;:il>le panties, and seltleirn.eTit of th.eir peod.lng litigadoo. ]"J'ej»otiiati[ons; between the;adjacent properly owner .anud tl:ie nE;srponjii:bl.e i[)ajri:ies v/<s;i'e i::urrE:nntl>r om-goiiriji: ait tins: itirrie of tJ^ieis.i|!:riijrig of tluis; liriE;ndiiu:nt let itlic leccuxl O'f K>ec:i.:s;ioiri.

Fl ';t Ifll 7 ci fti \ iJ IUI <!. iJ V

20

V/ith respect to off-sim properties;, tlie R.OD and .Mternatiive: lEt.isrniLiEtd.ites are the isjmie, with•lie exception of Une saturated soils, wixh would be excavated inider the: lEI'OlD andremediated hi place; under the JtE;rnative Remedy. Hinder the ]Et£)lD Remedy, the members;of thiEi ccMiHimiahy have, expressed concern with the movement of Mucks for the transportationof treated sioiilK olf-wile, and with the: disturhiuice: of a. snriall portion of the: Tulpehocken. Creekecosystem... The; JtE!niative Remedy i.s expected to impact the couMniniily to \i nriuu:)) les.seir(3iiE ;;:re:e,, both diiirin ; i::'0iis;tru.eti.cnii, and after c;o:risl]ruciKHi is { implete . An previouslyQi:;cusst:d. ithe: Siite will tuivE: mom Hfixibil ity ior fiitine uisie 'Lirulc Hie /Llte:'[:na.l:i'<E; IKeinedy and<;:;)i.ikl be: usE:di for recreational

Yi:. JSilIPPORT AGENCY COMMENTS

.All of 1-tie above ohstnges t(3' ttie rennedy have 1>E;en c ocuxliLtiat'EH], 'y ith. repti SMitELtir es ofPADEE* ijiursuant to « CP.R. § ::HM..435i(c.)(2)..

YII. J iEnEni]Ei:M. 'i[i:i)(>]M oirnns ISSTMTJTOIKY ]i]HEri[ri];iEi i:i]SfA:T]ioi 'SiElf A. has de:teirnrii.:rie(3i itlia.it this: ire ri,se«:l i tniieti.y (Hjurnplies with the: stalntory rEstjuiiireiirients of

CERCLA ii' I'M,, 42. U.S.C. § %2L Coiisid.eriniE; the new infonnalioiri thai! hans. l>E>em'Cle:'SMj]lO'][>ecl and the changes that 'have heien ncia.de to ithe !ie:!leciDe<ii iretnedy, EPA loelievcw; titiat: the.rennedy iremains; ]proi:iEK:llvi;: of haimsun health and the en,viirotinieml, coirnplles 'wiith ]E:ccleral. and!:ll ite reci'uii'einents thai, are applicable or irelievant and appropriate to lihis, IFEj iiLedJial A.ciion, a,sdtssciibeid i.m tine ROD foir OU-3 i or this Site, artel i,is cosit-effetilivc. hi addition,, this: irevised:re::rnie(3,y ».iti.!li;e :s permanent solutions; \ml ;3lte::riial:ivis: iLi ;ai:nus!n.l: technologies to ttie inaxiniurrie;(.teini. prac:t:ica.bl,e :Ecni tliiis, Ste.

VUL P1JEL1C lE'A.R.I'lJOlllE' L'TllOIS

A. th.:irt>' da>r public c;(]iirnine::nl: ]>E:rio:l iw.$m on June 3(3', 1999 and ws; e::«:i,e:]rii].e:d EIIIatJKliitiional. iiiiny iJLays to A,u(»ust 30, 19991. A pmiblic irne:i2:ti:rig WAS iwM on. JfiiJiy 13,, 1:9!5 alUrie Jackiion, Tc risln]} iVliuidciiiaJl ]E3 LiiJid,iing. The .AdTninistira.iti.ve Record, hiehidesi ithe: ]E(.OD»:s;for OU-L, OU-2 axul. O'U-3, ami all dcciurneiits. iihai: ibrirne'd Hie tes;is for EP'A's; se-kclion ofdie cleisinup ireine ly itn. the 'ROEta, A 'dra.fi: jnendnrient \o thus: !Eljecord of 'D'eyciiisiion ajridKtlajted idcKii^rnenJtsi \n\d die; iLtiifnirrriatic^i 'u.];K>iri whkh ii: is; based have 'heen ij[K:lutI,e:d in l:he

isitirai yiE: 'Reeord file: mil \.lw iiii:oiri]na,i:io[i rE:p<)sii:oT] :Ebf this, !:litE:. Thea'yailabfle i:oir uihliic min' at l]"ie lcN;:at:i(3'iris li.!Site<3l beliovi':

U.S. EPA, Region ID1630 Arch StreetIMladdphia, PA 19103-2029Hours.: Mon, - FrL, 9:00 a.m. - 4:00 p.irn.

ftR30256

Whltrnoyer Community Lihniry199 North Colltejge Streei:N'lyeirsto 'ii, PA. 1"!(W

The:- notice of. availability of Iliese documents; WAS published in the; L,eha:no:n Daily Newsmil a free local piihlieallon, i:h<j Merchimdiser.

Ferdas, Dinxtor]H[a;M3i:n:l(]'iLis .Siiitcs C!]leaj:i-Li):» DivisionU.S. EPA Region II.I

R '302562

RESPONS1VENESS SUMMARYFOR THE

AMENDMENT TO THE RECORD OF DECISIONOPERABLE UNIT THREE

WHITMOYER LABORATORIES SUPERFUND SITEMYERSTOWN, LEBANON COUNTY, PENNSYLVANIA

Puibllk C'Omraeinl: F'isrii«liJune 30, 1999 through August 30, 1999

I'l 10 O1 n 'fy K" (" *'!>UhoU^boJ

]R.<e&;p>n>i]i;!>i:vti]r.ie8!i 8uir.nLiin.il ryihitaoyer Lniwntimiis Supeirfijiiiid Site

yeir:s!l;owi]i, LebiiJiiniB Cwnnity,, PeiriitiiSiyJvj

This Resiponsiveness; Suirmnary Is divided into the following sections:

iiJE j'l'JSiHiHJtJ MEiiMSEfcLHjnd

This; section documents comments, and questions during tint; July 1 !!„ 1999Pubilic M««!itins» \v\i\di WAS held in the h\>:iiwii 'Inwiiisliipi I luni.ciip'alBuilding in Myenitown, PA,

Tliuis; section pr£>\ri(i:iE!Ei a c oiTipfeliitini /e respionus^t to all aii iiilicanitc;oniurneirit:s. ri2:cei\r£:(i in Avj-iling by EPA ichj;;rijriji; th-e; Public Comment period:.

jii:yj;J : u]m

This is^sKti'Ofi provides; a isuniLtiiiaj]^ of connmieritors* Tnajior issues anil concerns; and EPA'srespons 'to those issiJ.<E!s; and citjiicenus. during IbK Juily 1 •!, 1999 paibilic irn«s=tti.]riji;.. A copy of thecomplete tnmsicrip't jfiiwnri tlunt meeting is; included in ibcs xliTiinlstratlve Record. "'Carnmemtoirs"may indtide local hoineowners, including their iriends, relatives and counsel, representativEis;Irorn nearby businesses., elk:c;ted officials.,, and representatiives of potentially resi>ons;ihle parties

L Counsel Ibr a citizen was concerned itha.it EPA used the term "we" and "ouir'Vheri describingthe proposal and questioned 'who prepared the miateiriaJ presented.

£i! Ufc'$ » &-" EPA prepared ,thw Proposed Pkm, The majorhy aftfaamvnts were prepared bythe mpansMv parities itmier EP.AI '.y ovvmghl An expLmation of EPA 's awm'iigfn1 roh'. and therole of other Federal and State Agencies was also provided.

flR30256i»

2. Counsel ibr a citizen requested clarification for die record then: the cost savings of $1.!5million - $20 nillion was. Ibr the responsible panics mid. not the U.S, taxpayers.

j£!:iiJ!i!&&tf$ Eft4 agreed

3. Counsel, Ibr a citiizen did not reirneniber fl-iriy positive public comment regarding the proposedchanges during previous; public meetings and asiked if a vote or pole was; taken. 'He referred tothe: "Proposed Plan as a "propaganda piece" and questioned, tine accuracy of a statement regarding,the Stage's; involvement in the process.

,iie£!t!iLEJ&!jiE>&EiiftE.-' Nviihw a vote or pok -was aaksn\ ho &wr pos\n\ i Jeiidback has been reawwdduring nwn&rouy informal! tfiwuw-om with atumi ami local officiate.. The League of WomenVoters wm r&pr&svnt&d at the kisf, pitMic inMing and were infavarqftfw chan$vs disauiwedThe only m$afhw feedback received was from the Gnnnlnne ':», his diem'. Communication withthe Gntmhme rs has been limited ito periods when their counsel Ijs present. The PmnsylvtwiaD panmeni of Environmental Protection is very mvohwd with the project , mvtewmg alldocwn\mts md participating in disa&wans regarding pnjptwd changes to- ;f/i«i remedy,

4. Counsel lEbr a <:iiti;?:en n ciuiest jd an esxphnriatioiri of the ul)ottleneckri at the Fairiane k.\reni.iec;i'<s«il:iE! a ilood.i.irig problem.

££<£U&'tiI&>ti-S&' f'N order \o excmtite manned .mUs adjacent t® the Tidp&hocken Creek, wewould have to dmin the wa?.$r away from the IMpehochm Creek sam&h&w ffitiing it acrossFaw'km! Avemtfi via a large conduit Jtfi'hem was a si' n{fkitmi\flttm:iiin ' event while diverting fht*creek water amid backup mdflmd the areas behind the diwrmwi

5. t\ dimn ini:iui:i[ :d \\ovf tl te Lin.s«,itui:niiLt<ji:l soils i3ucljai;;eni; to the oreek w/cujl'd be excavated,

<!i!i:!dLjEiiij5jE!ti!iUtiK/ > o:mf'witll Iw diverted into the cmk in if/ie area ws\i ofthv vtmll Sandbagswill be placed at the sfatice gate to isolate that tma, Sheef piling will tbe driwn into the gnnmdadjacent to the creek. The M'cavaition mntSd proceed to the fop of the water table,

6. Counsel ibr a citizen 'was; concerned that EPA. wasi portraying tliwE! p>iropO!»ed. c;hj3i:rij3;<Ei to theremedy as rel.aLti.irin, to on;nni<: coiritiSLiniitinied soiil.

$Ed.J&?$$W£& The change to the organic vantamiiKtted 'soils Us one pan q/",r/ie remedy change -changing on siite freatmenf of organic otmtam$m:tt$d satis t® qffsste treatment. The. other .twochanges are mMin$ .mtotnxted soiis by p ^flushing Hi? the msatw-ahvrf zone by etiminaiing the impermwMe cover.

1. CaLins«sl lEb'ir a citizen inquired about the hill (i.e.,, change iuri l:o]pt>];;ra'[)hy]i o:ri l;he saiiEt ujruJ,eT' the;oriji inaJL remed.y juncl the ]:»T'i:»])<ose:d remedy. IHtes iaJbo quiEtsrtioned the impoirtaiios: c»:E'ireusin;t; tins; site.

£A..Rtl W .: &f*A responded thai under (he original remedy, th& hill may be up .to 4dfw(high m some areas and on average up .to 2.0 feet, higher. Ih? pmpmed mmdy change milincrease the topography approximately 5 feet thnntgtmtt the site. EPA emphasized that re-usingland at Super fitwd sites Us a national priority,

8, Counsel ibr a citizen questioned the importance of neighbors property whkh had becomecontaminated and requested an explanation of the area to be; excavate!

EEA.R$.$&im$:- .E.PA resrpond&d that msghb&rs property is also extremely imponanL Theexcavation houndams are primarily the same - the mam difference between the original andproposed remedies is the depth of excavation. The original mn&dy wqwres the vxcavflilion tocantimte down to the, top qf bedrock The proposed remedy reqrnres $h& vxcesvoHion of soil downto the -water table. EPA 'was corrected by the wsponslbk1 parties ' (RPxy contractor tfrnt thereare some limi i\vd areas that woidd reqwre excavation under the original mmdy (L e.tconiammauon timnvd to the saturated zone only), fan' the essential difference ?$ the depth ofexcavation.

9. Counsel for a citizen questioned if the ground water treatment plant could have been builtlarge enough to treat the HI million gallons, of water estimated to be created in the satuiaitedzone.

EPAJi&§Wl&&' EPA responded that the groundwat. r phmt was InM before the estimate of 30million gallons was generated The RPs * contractor discmsed the diffiadnes m estimating theexact ammmt of water that could be generated by the safiumted zone and adtf&d thai the designestimate for the plant was based on (ground water) welh -which are mow predictable. EPA,&xpkwwdfhw'& were other aptiom .nich as treatiwg 'water at an offsite plant htri that wouldnnqmre a significant nwnber qfi'ruclh each day,, EPA also discttSMd that removmg &atwaf®dsoils 'wtmld wot provide a sigiwftcant benefit because confomwKtied grmndwater would re-witerthe area containing the clean MM,! after the pwnps and sfaeef piling "were removed,

10. Counsel jfcf IBL citii Ein iaisiike l if the ground Avater tsihlig: coukl be k»v :red ifijjllier.

E£A.B ffJQfXS&f' 'N'w RP 's cawxniaot' was not &itre sf the water table caitt'd be. hwenid further andexpressed concerns abtntf handling such a large 'volume of 'water. EPA. agrees with thisresonse.

1 1 A*. seci:nn:l attorney re]:»:ns!;siiBniiii|:; tlie swinii-Es <:iitijz;'E;n quiftiti.on.ecl 'why the ori.jji.inal I'eTncN:! 1selected this cleanup approach.

•££ [J£ft3E&tf3&* AX th& time of the decision, the xoM was awskfared' to be a sawce ofcom\ammaiion to the ground water. The RP 's contractor added that it way her underxtandingthat rtfjf i'he time of the ROD, the ihwkness of the, sm trmted zone was thought to be only severalfeet thick. Add'iXtonai' mmpting has shwwn than the &:\tMrat.ed 'amv j;.s' much thicker.

|!|R302S>Ei6

1 2 , I"he same attorney requested an explanation of how we cani dean the soils; with ground waterif the contamination is not moving lErorri the soil to the ground. wateir.

E£dJi&i W&: E-PA explained how the saturated so\i is not the original sourav of arsenica:mttmx\natww; the lagoons and the amite disposal mas appear I'o be some of the majorsources contributing con mnation in ground watM*. EPA also discMS$tMUKM\fhxK&i$ mayfatrw contributed to wfaoe contamination for the hm-lying tw&as. EPA provided an vxampk ofjhtskmg colored water from a spm$w and vmphamed thai all gramd water in the area of thesantrated 'soils 'will be capturvdamf treated

B. 'Tims: sanie attorney requested an explanation of 'why toaokiilliiifj; derail soils will \\vi yoniKrwhere if the •;njirnp-andl -treat s;/stemi is remediating the soils and the ground 'water.

E£AM$$l&Wl' &P<A- iMpkrinea! thai fhe gramd water clvmup mi! tak& dtaidvs.. .If ww excavatesafatrat&d soils at Ms .time, the clean soils that are backfilled will becwm' conUminate'd by th&graimdwater in a F'&hmwfy show pvriad of lime, i. e. „ sh: months to a yvar. EP.A aho n'-sMedthe technical concern's,, e.\peckilfy water migrating $n$o the hole while oxwnwififMg saturated soil's:

1.4. The sanrie J3.tt:orne r njiket], if the ];»u.irn]>-jai!r»i-i:nESEit. system w\M r<£:riH2:diat<: the: soil the back--filled saturated soils.

E AJ lW .- EPA mpandvd thai tn^r tmw, contamination in the m\fa would decrease sfawfyhut. $am& ccmtamimthw would t wmain, wgardlisss if we excavate salwvjtivd soils or Ifsaftmiivdsoifo at1® left tin place.

15. The same attorney ian&ked if tins; (i.)E!:s«)rpti<:«i irate from soil l.o jSjiiouitHii water was determinedand :if not,, hov*r cajn v^e ]:»ris:dii:rt the effectiveness, nf the srystemi.

E£Ajl$&'$$&n&il' Tfw RPs ' contractor .shMed fthty$ desovpiion sntdies mm conducive dwmg ithwRvmedhi! Jm>esti'gation and th:\t flushing tfwa imfa wiN be more effecMvv than nm! flushing thesoils. The actual dworption m\\? is kss critical them the arnhwwieni qfihv. ground wafer,.

16. Tlie same attorney also requested an estimate I'es iajrdiniEs the length of time to remediatesaturated soil via the (ground 'water) flushing system.

EJPA.&MWWJ '' <to- -ft '-' ' MWiftwcf&r stiaMd tiwtt under the original remedy or Mi® prctpawdremedy, the deration of the cleanup .Is mlMMy so be sigmfsamffy dtffvmnf because the mstmajority qfanwnic is m the growidwotter ami not in thw stnturat&d mUs.

1.7. iBoth attcntie>!3 for tlii'E; t:\il\mn questioned if this; method 'would take 10,000 to 24,0(30 years.

:l:i£<SU&$|2& Stf:- E.PA. siGtwd thai ,fil will ittn\w wwmi decades, pwnsifoly 30 to SO yaws, althoughihis rji vwy difficult to predict The rvmetfywiHbe w-tfmhMtiMti' mtty if

i.s effective.

1II A, citizen requested, a private meeting between the attorneys representing an adjacentproperty owner and the EPA. and/or representatives from the responsible parties.

•jic£<'Ui'ft£j3CHjE8E'*' Ajf3>l •tf$frrecir to have a private meeting with the attorneys representing theadjacent property owner and contimt&d the meeting with a videa presentation highlighting theformer lagoon area thai 'was excavated and showing the sott areas to hw excavated in the mxlphase.

1.9. A citizen requested the estimate for cornpletiiiji; tine ekiani.ip' Ein<:l transforming the site into apark

&£A.*R&W&Wil' 'fiFW responded that it will fake abowl two yean, to compknte the cleanup. Inregard ito the park, thai depends upon the township and the ability to locate soums of funding,sitch as grants.. Othw ahematm?s to a park setting -wtmld be an open space alternative wtihdeed n?$ft'h:if.iotns on the xubsw'/ace soifo..

20. A. citizen -wais 'KcjnceTnuEscl if there v^eriE: any plannedl e:<:' av'J3itii:m Eictivities; on their property..

iE£AM WS.' EPA ami'the RPs' consultfamt idmtifwdtiw qffsite twatrwn'hm areas -which werenear, bin not on\ fheir propwrty.

21. The attorney ibr ajn adjacent properly owner stiatted that one of the positive aspects Identifiedby the EPA. v/as thait it shortens ithe lime to complete the cleanup 'by EipprO'xhnately two years.

ibEA.&tl$lMM$&-' EPA agreed.

22. rrhe i3.'tl:ornnE:y ire^njnEssrtijcl the ainou.nl: of time necessary to deem, up the soils under ithealternative being proposed

^ LB&tf W'Sj-l-' Thtii1 &ttkwfa'tian has not beenp®rform&d. Btwd on new and additionalinformation, eMnnahwprvptmwJl during the original sei&ction of$h& remedy may not heappropriate.

21 The attorney questioned if 'backfilling with lightly contiirninated soil! would coirnply withPennsylviajiia's ClejHi-RII Policy.

&EA.R&$$®n$&; A ntprwyent&tiivG Jrom the Pwmsyhania Department of EnvironmentalProtection responded that xi met. fhe Act 2 n ni'Jrementii S/w wouitf check on the Ckan-FUlPolicy.

24. The attorney questioned if covering moderately contaminated soils, can the site met the Land

AR302568

Disposal Restrictions and the Clean-Fill Policy.

E£A£ ltlW.il.' The proposed mnetfy me&is the Land Disposal Restrictions and we u'r/,1 check onthe Clean-Fi'H Pohcy.

2!>. The second attorney ibr the adjacent property owner requested iuri explanation. of how theproposed remedy is expected, to achieve overall protection of human health and. the environment.

ERtiJJi lltWil* EPA mpondvd! that by pumping and treating gi%ntnd waiter, we wilt removearwmcffwn the Mifttrated soils and infihYation will asusisf with removing arsenic from theumaXuratffd -torn. Th? RPs ' cwwa tirn exphiin&d that you tmfy have a mk when you have awexposure pathway and a receptor. Arsem: in the saturated zom* covered by a soil barrier cannot reach a recepfar. In addiium, there is containment, capture, and XreatmtM of ground walvr.

26. "I'lns: second attorney asked if the prohibitions about consitrudtinft landfills in wetland areasand kn liiinestone eifLv/iionjrrHSint.s. vw& cx:i:nsi(iE:red.

E LRin&n&il 'Mw $'£*' ''• Gonnthmt nwponckd thai' tk regitiatjom were cwmidm'd in detaiS.The PADEP Pro/eat Officer mit&d th:\t the cmifhm of a hwsdfMl at MW si&v way t&tcwxwd manyyvat'x ago and the State objected to the 'siting of a land ft H .tywc{fh:atfy far thaw reasons. EPAadded timf the regulation dtws not apply bwamiw w& are not cretitmg a landfUl. Questwmregarding hiw$ tmd regulations shautd be mbmittvd m writing to EPA '$ C&umwt, MX.. PatriciaMilkr.

21. t\ <;;itli:en askedL if someone was going to mw tins; area,, raising cxniiCEsrns laibcmt tlnj presenceof 'thistles.

EEA.&l lWf .- EPA responded that $.\\&y would speak with thwm after the mwetiiwg to ®vahm\v ifconitwimai&d soU LY present and ntsohw their concern.

EPA. :LnJ:c>rnrie(j[ the citizens tlia.1t l:li«ir«' ha\re been sionrie discususwm re,[;ujrdHng the; exltensiioi:i oi'itlie:coiiurinjirit: [3e:ii.od. - ri adveitiseirneint Avili'l \K\ place:d in the ][.j»im;i]]L.I3tib:.WjSii!i. andl t:he:] IJEtI [tlj)J[ldiEi!EU: if 'the; public; comment ]>E:riod is extended an additional uluirty clays.,

AR302569

Part II. SjJLHCUmi^

(Counsel for ithe adjacent property owneir requested an extension of die public: corninen.it periodEPA extended: the comment period an jMlditi.ona! thirty days until Au,:E;usit 30., 1999. Counsel fbirthe adjacent: property o'wner requested a. one-day extension and submitted cominents on .August3 1, 11999. A copy of the comments are included in the Administrative Record mid a point-by-point response to itheir comments are pirovidedl below.

EPA [received! a letter on July 26, 1999 from a citizen concerned that contamination in the groundwaiter will continue. The citizen also raised concerns about the bactaflow of water into theextraction welk EPA provided a detailed! response on. July 27, 11999. A copy of both letters areprovided in Administrative Record.

Congressman. G-ekas;, U.S. Mouse of Representatives,, submitted a letter dialed July 2 1 , 1.999supporting the proposed changes to the remedy and applauding "EPA's- diligence in developing aproposal that, is more eifreaive than irts original plan.11 On August 16, 11999, the Jackson'Tcnvn;:5;hip Board of Supervisors, submitted a letter supporting the proposed remedy stating that it''"niiSLkeiS. Ibr a more intelligent cleanup." A copy of both letters are provided in die-Administrative Record...

The fbllowi.ng is a pornt-by-point response to the comments raised by counsel! Ibr a,n adjacentproperty owner. The adjacent owner is; currently in litigation, 'with the responsible parties, andboth groups are currently negotiating a settlement of the litigation and the purchase of theadjacent property Counsel (or the; adjacent property owner stated they would withdraw aJ.il oi'their comment*; cm. the proposed change ito the remedy pending an equitable .settlement for theirclient.

TJu1 proposed remedy wilt, not remediate the amtammated sot, Is and wilt, injuct, place nearbyroperty owners and the mvin'mrnmt at subsmnnal risk.

'Both die ROD artel Proposed .Remedy remediate tlie soils, as defined by the NCF, since bothuse a combination of excavation, containment:,, trea.iuniKii.it, provision, for alternative watersupplies,, and monitoring to |;»:rc»t(:t ihv, public: healljti and 'welfare ;3in.d itlus: iTr/iro-irinrifMiiit ,

11 As described in .Section 3(X)..!i of thie NCF, "remedy or remedial action" means those .actions;consisiftril: with ][>erniELne]rit n rnccly tiiloKii \m\ffi$d of, (]f in. addition to, removal action in ilie eventof ;3i ireliswis&K or threatened :re:lease: ol' a hazardous substajrtce so litiai: itlusiy do not migrate to causesubstantial danger ito presieui: or future public health or welfare oi' tfie eiriviironrmeni:. The: \$mincludes...such ac:tio:tis...jrea:s.oiiii3ibly i :{|UEire(J11:0 assu.;re: dial: suc:ln actions; proi:ec:t: utie public health

/IF! 3 02 57 0

In addition, line Proposed Remedy is at least as protective to nearby property owners and theenvironment, amd probably more s;o. In the ROD, E.P-\ identified mo potential "routes ofexposure" (i.e. means; or path-ways Ibr the contaminants to reach potential receptors) in whicharsenic or organic compound i:n soils .and sediments irnijiht pose an. u.:naccep>Kabl(: le;v :l of n=;kto nearby |}irope::[ity ow/neirs m tirie envnoiMnent. I'he se; im:

* Via inhalation, higeslioii, or dernriali contact (i.e. dlnsicl. ccmtEict); ;Einti:L,,

o Viiei in:[[e:!3tion, of ground water that has been iin, contact: witJti coiritamLinuaLtecl sioiils and•e;<.cee:ds drinltiniE; -miiM? criteia.

Tc» i uldres the: potential for inhalation, ing<:!>tio:nv or dermal contact 'with contaminated soil:;;nul/or sediments;, EPA*. s:h;:i;:te:i:l a PEnnedy of at leisist twit l!ieKt oC cllean soil over soillfl(2inci E:diin|; 21 ][>p:rn itotal, ajr ein.i:;. li!]f*/it d'et:i2:nrnineid theil. such a rcrnKxly 'wwM l3«: iproicecti : ol:ne Li'b ' ];»rc)]>E:rl>' ovyrne:;[i3. and the environment, "rimst .^LiiriendiirKiint. has; not alteiftd. Utii.is> ]>orl:iio]ri ofllru: Reme;<:h|i ., Iltnjts, uin<jier either Hie 15S.OK3' or the: Proposed Ecnwdy., UIDB pctteiritial. lE(]'ir<:xposu::c i:o arserLic vi;j dlirect contact with -.oils; is alleviated. In lact, the Proposed 'Remedyiisi niore: pr(]>tecti\re oi' nti2:Eirl>y property O'y nn2::r si.irice: (131) l.«!isw. soil, will be excavated,, thusreducing ilu: i>[)t :ntiaJ riskjs. a.S'SC ci.iaited 'with ijlistxirtiajrice: of conunniratcd =.oils, and (b') uii:=porti.i:»n of tt»: rern<M;l> \vo\\k\ \w iinp]it:mente<ji more quicldy smce Uti« constructiion. period islew llian llialf 'liat it Avcmlkl. l>e 'Linden Ihe ROD.

I'o atldi'ess tlinK potential ifan iinjs estii'on of ocniutanikiatol. i2;:round wateit,, \:Pt\ selletrtiEid, a, nsnricdyof c;onta.:inme::nt m define(3i by tlie IVlit L-,,, anid, t{) tJtie extent practicable, restoration. Tliekjrne::n(3i:rn :nt has not altered titiiis. ]>c)rt:ioiri oi? tlie: ]El.einedy. Tlmis,, iin ksr eitheir Ufie ROD or|yc'i:>[>ctse(i, Remedy, the pi:ne::ni:iai lf<>:r cxposuire \o ai'Sisiinc vi,:3L itng'£:sti,on of ground va.ter is

wwllans: atid the eiwijcoiiBienl:.".•a: il:n tlw:: B.01!>, 1:IPA. seli ctist'd a. renriediy oi' twn l et: ol'cliean soil, ova lii|;liit],y {:ontaLinn:Late;d sioiiis,spedficaUy for protection aftainsit dinsci. conm;!:. The "upgrade" of dm cap over tJrie site: properwas specifically for pinposes of lliiniting (he poeniMl for comlj«:nijriant iiiLigratioiii 1:0 poiurui. wate:r,:n3.tlin2:[' thiJjri to provide an iin:i'i;:ase piroteciticm againsit t\\m?.t c:onl-ayc;t,,

IVR3DZ57

The Proposed Remedy lacks the cenamty> rdiabiihy and Mifvgiwrds required by the NCP.

In the ROD, E$A elected at remedy of itwo fleet of cilean soil off-site to protect against thus:po'tentiai for direcit contact with lightly contaminated Mils. Under the Proposed remedy, tin:soil:? cover v/ould l>e extended from ol:f-si,te to on-isiite over moderately coiiiarninated Mils.Tliis willl ajllow precipitation to migrate ittorough ttie soils carrying residual arsenic into the['round watei Ibr capture by Utie tireatnieir.il. system. Thus,, with rap t to protection againstdirect contact with soils, die; Proposed. ]K.emed!y would be as certain and reliable a;s; the ROBKennedy,, iddkionally, the same safeguards would, be taken under both remiedks.

Similarly ,, in the ROD1 Ranedly, Bl:>/ai jje]lt;ciJE:d, ;i remeclj/ of poiiocl iw;aiter [juirnp ann:l treatmentand continued ;rn,oniiorini; to protect against the potential ibr ingestion of contaminated groundv/ater,. Iitii.:s. \m> icioi: clKijri||;(2:{l uituier this: Proposed lELemedy. 'riinui,, wiith respect to prourcuionagaijisit i]:L([;e:itioiri of ,[;roiLind WiEiteir, U:ie l:tix)i>c)se<:l Keniedy wa\M I>E: ;SLS; osintaui and reli;3ih]!e astine ROD Reirnedy. Additiionally, Ul:ie S.EIIIK: sal:egiLtiurdL;Ei 'would foe tajkea uineler fooitli renciedies..

Gtmmmt 3.

EPA hay improperly athmwf. WLPSG to- proceed for tfw ptuf £uw<ind-one-fati(f years based onthe Mstn&mpXwM that the Proposed Remedy hay foem approved., Furthw, nnhw thawperforming the ROD renmfy., WLPSG fatu spent the fast few years anwmpsmn w gmerateevidence to support, the Proposed Romwdy.. .tis a rent&t, EPA has ailowed WLPSG to delayiimplementation of th& ROD remedy for soils since 1990,.

EPA diiisa reeis,. Since .1990, cleanup at Utie site has picceedffd. »i: m a||jE;ressive pace.JVuniero'us clean.uj: ac[]Oi:L= hwv Itieen crotnpkned at: llu: sire, including dernoljition, and disposaicfl];u:an]ou:5 I3iii.il dings and isitnicitutes; renriovaJI, treatment.., and disposal! of\±<i vault contents;removal,, treatment, and di:ipO'!sa[ of the former lagoon an:a :; and installation and. start-up ofthe ground waiter pump and {XVM syjsiiaB. Sij:K:e PEW, i3|)pr<:>x.]LniiatC'!ly -iO.OOC) t<:««i o;fJtia: aLri:loiLis and non-hiUianioiu material l .vc Ivii \\K is;ite and 60 tn.ili.ic.n t;;i lion;; (MG-) ofc;)nt;in)Ui;iu:d jj;rcMj.:ri(JI \\'i\\:vr ituivt: hetni |-c:covi:'[i;:;l ai:i<:l (jrea.tE:(Ji 1:0 meet or exceed alii criteria.'llicsc actions have IX:EMH :5C'i:|iJ,is:no: [l inn the most :>a:fe, el:fe<:;tive., and efficient maiuriei- and ii: isonly now appropriate to he^ki tJne n::n:iE:di;ii:ion of soiils and ;§edi;rn,e:riU3 .,

[;ri pa:ndle.l v/iithi i:he: nbovv jiativiKia... WUf^JG also undertook iny<::ii:i||:i3itionji (]f soiils andsediments ito complete the characterisation and 'Cle:lli]:ieati(]fi ol: tlie: siiite in ia.c:{;C'rdance with tins:ROD. A& ;3L ircisulit of thesie ,s;itu.i:li,<s:s, n$w liiuFcmrnajtion vk'.eis obtained regarding the nature,.extent, and behavior of conu-inlnatJion at Uhe siim. Tins: ireisuilts- of these studies necessarilypronipited ;ai review of the ROD ]Ei:en[uuJly ajricl the development of the Proposed Renciedty, siince<Jk:s::rib (] i:ri tine .Dira:[ii: M.YD /ijriH2;nclinent.. ]E:iarthi£i[:rn.ore, iit i:s appropriate to conducit .situKliiiKSarKl d,e,s;ijnis while c;o][isiderijfi,[; nru>clii:f]k;ai:ici.nj; to the: seiecl d rencieiily.

AR30257

Comment 4.,

Published summaries q/'irte PYopos<ed Remedy d'£rJo,nr tk$ subMtwa* ofikv ProposedAmwidmenf.

EPA's published. summaries accutateiy describe: the propound. changes to the: 1EI.01CX Inaddition,, detained. dies riptionus. of Uric piro'poscxii change® have been provided during; at leajst twopublic: forum, inKkuliiig thus: most recent public irn.eeting held during Utie coirnineinl. period.. ppiroxiniEiiely 145 copies o:E' the 'Proposed Plan 'svere mailed to nearby citizens and otherinterested parties on 'EfA's sftsMSpecllic nfiailijcii?; list:, 'BuJLIc: d:>p:ies of thus: !PircrpCKSKs>cl Plan 'H/eirusent to •[];<;: ]a;:l;j=on ToA irtship Municipal! !Ekiild.in;E; ann:! the lo::al library 'which" contnnis theijrii?0][niajti.om repnstety. Finality, detailed description!! of thi<e piroposied, chEin^es and isiap oirtin ;<3[oc;'Ln:ne::rHJ3Ltiion vere p'lLacei:l into t:ti«: ijtil:niri]ria.i:ioi]. re|>»si.Kn>i[>r ati.d a(lrnii:ni.:s.tnEit.iiA'e reccrrd,. \v\uvhare r<;: Eulily acce i'hlk:. Tliais,, both, ttie !iu,b!jt3.nci c»f the; ]'»ro]>ose:i;l remedy and thecommentators concerns have l:»Ken lEiJilly pireisetiiisscl to the public.. F'olk)win.E; l]:ws puiblicfori]jn:si, l>oi:ti tlie I3lenj[isylivajnia. TMfiP and the Boiroiigh, c»l ]Vl;yei«tovyrn, Board of ;E!upeKviso:n;|]iiEiv«: i jE.];»ressE;(3i l:heir surpi nrt: ftMf arbd ccmc:iLirrenc;iE: 'wiith the; Ifirc JOiSusjcl. ]?t.e][in;:d>'.

€(] l/N E'Pl.f 5.

The sunwiaritw npmene thai if EPA mpHennmrs rh& pmpmal, "detmup of the mtiw sine,exdutUng ground water,, could be: compltMd in xwoyetm. "' Hmww, under EPA''s proposal,all. contaminated MiUmMd soih' and on-siie moderatefy ccn\ani'maU'd umauinned misbecome pan of xfw ground mixer remedy, which hay an imdektrminablv coinplvtwn date,potmr'ialty hundreds -ofyetm mio sh$ funm1.. The: proposal wfM iwf acMeve: cleanup goaisfarnuiny yews for the mis left in placet.,

Uncle:!' UK: Prt)|K>:iea;l Remedy, HE:inediia,li atctiKin (Le, ckaimip), as defined by tJtie NCP,be ci:inri|>:ts:t:iE:d ijri apf»ro;iinria1:el>f two years, ccunpjJiit El l,ct five years under thugs 'MX) Remedy(see 'Response IL). Afux miiw\w\. action, und.er both, llie ROD and die Proposed l einedy,,signaricani. volumes ci cc>:nl LtninELle:i:l soils v/iilll ireniain on ttie sii:e (or an indefinite period,Neiitlw itlws: ]K(7D n,or the; ]E»ri3poi3««l Re:inn cl>r -will, achieve cleanup of gmn\d( wi\\$i 1:oi manyyears .. Wiith time,, unclear Ihe Prtopose l Reniedy, airsenic iJtiat cm. readLily cleiiorlo iiroirn t:t«: soilwill <:lo so. 'Tlids "dissciiLvi^d11 ars^tncic will 'then, \w c L[}icii,]rei:l by the; ground, wateir [way ajrtclti:e;3it systen:i and peniciam nJLly irearnwvis&d IJ'onri the she. Htol:h ren:ie(3.ies tnusi-Kl: Ufie riEitnediiEiloibjectives idaitified in. liie ROD (Sec- Rapome 14).

Comment 6.

A[t fh& public mwtin\i, EP.A eMiimaied \thaf re-mediation of the mis nmkr the ProposedRemedy would take 30 to SOy&ars. Howvver, upon further requen, EPA anti W..PSG havebeen mtMw w provide any vstunatff of the tinw reqmred m nmedui&e tfw soils mi the pumpand mat system,.

AR302573

E\:tA. ajrid. numerous irjieniibeirs ol: the: technical community recognize lilia.it sub&uimtialuncertainties are associated with predicting the time frames to ireniediate ground -water ait thisand many other sites,. The relatively ;Sihoirt itinie frames over whdch treattneni: systems haveoperated at oilier contaminated wa.:si:e siit.es adds to this complexity i.:n that Inhere are very link'.empirical data upon which to base estimates. Thirty to fifty years is typically used forpurposes; of financial planning (i.e. present worth analysis) or hi evaluating the technicalpracticability of groundwateir restoration. .

Prior estimates of the expected ground water restoration period at 'Whitrnoyer have beenmade., but none pertained ito> llie Proposed H:einedy as currently configured. Ideally,, such anestimate should be made based on several years of actual pumping data, from the site, uslnja;sophisticated :rnodelln.g techniques. To dale, only 15 iriiondus. ol' dlaia a:re available.N'evertheless, ajri oirder-ol '-magnitude estimate has been, made using very simple nieithod-Ji, andafter making several Eiigm.Ekar.: ass'LiinpHtii n regarding i:tn; mass (]T arsenic in tine site soils .andpoujridwater artel tJtie dliEssorpntion. cliEiraKUsinsticK of arsenic (to lie. provided under separatecover).. Under the EjOiD Remedy., .ground waiter 'would not: be: iKx.pecitedi ito> meet MCL& forthausandis' of years. Under tine Proposed Remedy, using the same metliod and assthis estimate docs mot: change nneaninislfully. TIuns, i:h ::re; a.][>|]Ns;ars; ito be: no 1tK:i:iei:it: l:oRemedy with :n;:s;[)e:i::t to the: ground water restoration!

7}he Amendment proposes a i xer cleanup (jta will ctutse and leave, in place gwaiwenvironmental contaiminalion than ike. mnvdy wiected by the ROD,

As defined by the1 NO1., both remedies achieve "cleanup-111 (Le. iremedialjion) of trie site (seeResponse 1)., I'he yoliinies of CG-iril^rninated ]rn^Jteri.iail !<:•:[!: iin. place under tliws: two ri£::rne(linE:s arevirtually identkal. IJ'iuJler botti JJ:ie ROD f<\n:\ Proposed Rennedy » all moderately and liightlyC'Ontjjjrninale: ! soils, are left on. Urie sil:*£:, allheii. ijri diilifererit areajs. vbrit:hj.:ri the site: and. coveted bydifferent, maiterial/' Undeir tJtie Proposed Remedy,, an addhi.oiMl 700 cubic; yards (cy) ofheavily c:i:)ritajrn.iiiu3Lt«i:l .saturated soils (of the total 1.7,000 cy of heavily contaminated, soils),primarily lun.ited to the 'Whtornoyer Laboratories properly (I.e. Lot 44) will al.so r ::rni3iin onsite, '"rims: upper portioori ol: ith.«: hKavily 'Lioirit^jrnJiLitcdl is^-tu-Taited isoiiis will Ix: e^EcavaijKd wilii ithe:overlying iinsaKniaited isoils, tJ:i'E:rel>y iurthusir reducing tliis luiiiiizd voluniK which will remainl>el.io ^ thiK tcr[j of trie waleir l .bl<2: bennstaUri 'tins: site (!S« .l es]>onE ; 8). The inassi of ajrsenic ijril:he 7(]() t:]|ir irepreseirit^s. nriu,i:h le:ss tJ:iEin I % of the toital. irnajsjs of arsenic ijtiat ha\'e ;ailrea<Jly he»nre]:n.ov' !:d from the: lagoons arid, veudt o:r v/illl be reinovc<jl fr(]i:rn. tftie ui:ri!>ai:Ln:al:ed. Imstavil;^contjjrn indeed =;n:.ls,

;i Foir []ijui[)(]»ise:s of tlids iresponse, unless :ri<3'ite(3l otherwise,. EPA II LE; adopted iJhe NCP ide&iition oftJrie "site" as extend in js; ito tie luiiiLi of c:o:ni rnination.

flR30257!»

A;li:er die 'ROD Remedy is iinpleirn.enttid, it: its anticipated that, no liurlher arsenic would Ix;removed ftoin the site. A;fi;er die Proposed. R,eirn.edy is implemented, lit is anticipated thatsome anienlc from the site (unknown quantify) 'will. be: recovered by Utie ground. wairar pumpand tnsjal: system, foe ultimate :re::rn.oval from tlins: site,

Ctwnmmt ft,

'Die Amendment proposes letivm$ in place conttmmaied mis well in excess of the cleanupstandard of 21 ppim imwmc.

The arsEJiiic concentration oi' 2\ pp:rn it;s a, cleanup "ciriterion1,, as opposed, to a "standard"', lit isbased on background coocenlratiotis oi arsenic in soils, (i e,, nEilunilly-'CCCULrring} arid is;laicli'Oiri-ispecific. Hinder both ttie: E£\][]\ and tlie Proposed Remedy, soils in excess ol: 21 ppm:re:rnain on-site. l)':ri(31er itlie 'ROD,t \\g\\tt\y c;'ontajrni[na,i:ed sc>il.!S. exceeding Utii.:s. ciriteiriion wwM becohered 'wiitln ;3it least t:wo icet of clean, sc:il >fc> change i.;= ];iri:»i>i:»se(il 1:0 Ltii;; portioii nl: tin:;Remedy, otlner than l:o ijrnipjlenieni: iit moire, quickly,, as 'o-uld be aci::oi:[i]:ili.:sliedl under theProposed Remedy.

Under both tine ROD and die Proposed, liternecly, moderately contaminated is.oi.lis, aJLEno inexcels of 21 pprn arisenic, would rarnain on the site, albeit indifferent areas. wiUtiki the site;3Ln(dL i:o\rere(Ji by different. materiaJi. Tins: only (].il:[e:n;::nce iji ii|;i3.:rd t(]i iitie ajcn.c»u.irki: ofCGatanunatcd soil le:(t in place is ths: lirniitcd aniKiiJint of I'lijj.bJy c(]'irit [[nini3Ltei:L saliarate l soiJs(See; Jkesponsie 7). EP'A .a(:]cn,ct«/llt:d;K;<:s that int innBiy \K>, wMmmisiiy difficuli: it(3- ii:[n|)l<2::n]Len.it the:£:;<x:a\'at,iLOiri of saturated, soils down 1,0 itlie i:o];> olr lt«:(3ln:K:l<:. N:ov/is:vc::rp,, EPA. iis inoit oppo s d lioexcavating t]:ie upper pen:ion of the: sati.initcd IGDE: and shaJLi dined: Utte resporLs;il>:iE: pan:i<::= torerricdiatc t.tit: soil;; i,n \ht: \''Mwwu\\i rcuirin.i . , s tine e;cc,3 'ai:ion of heavily <:;ont;3jrn.in ie(jl soil:3|)|]':rpc»ac]tlu:s title zone: i:»f is itULnaited isoiJL, W'LPS'G willl conti,iriue: 1:0 e jc ryaie: Uie soil iinto thiei-ipper portion of 'tlmEs .satuirEite l :3:oirie to itlie «;xtciit: ];>ratcl::ica]i, Utiere1:iy maximizini; tine amoiiiniit oi::=oi!i 'that can be excavated. Excavation act [vines will :ncnt be \in\\:w\ until niter i:b,c saniraiJE:d.

While repmenttng Mm the smLi >m Jitwr a primary noum of ground waur cMamunnifMPWLKG contends Muit Mw gnnmd Mieiiirr P\mp ami Treat System m.U somehow rmediate bothsaumned and \mmlun\tvd so'\l\, 'nese mndp' x are awnplerdy inapposite. $ fh&ctmtwnmi&ed soils are not a sounw of ground water a:muimimitmi, tfwn the Pump and TreatSyxt&m canniof mn&duiU'! skew .wills. Hownrwr, if amtamination iwv$$Jhwn mi to groundwater, then the xoi.1 is a smrw ofgmmi water contiimiiunion, and xfw .mis am be. wpccledto spread Mw ctmtamimiitm.

V/LPSG's coiicllusiioici thai, titu: soils do lao-t jgippear to be a sdgBilFiaiiM: isou.ro:! to t:be p:»inid.wai r

R3n?57R

iis based cm numerous observations made a.i: tin;: site during site investigations, These include:

« Arsenic has a relatively high coefficient of adsotptlon (i.e. propensity to staytightly bound 1:0 soils). Ibis is supported by tirie expert: report: prepared by Dir,Fendorf on behalf of the Commenitators (Attachment A of die ConirnenUi),, Inwhich he concludes that very little, if any, desoirption of arsenic is; expected tooccur.

* With: the exception of relatively isnia.ll volumes of heavily contaminated soilsremaining in the saturated zone (see ]R.esponse 7),, all. of ttie contaminated soilsremaining on thus: site axe w>Kll bvkm 5 irn.g/1 TCLJE1 arsenic:, indicating thai they a.reIeac;hin,E; arsenic into ground water at veiy low concentrations ,

« .Sl.giiiiflcantly le;s;:s. mass of arsenic is in the site soils, coinpar-ed lo ottieir identifiedsource areas,,. such as the vault and lagoons (since removed),,

* .Arsenic concentrations in ground water traversing large areas of contaminated soiilsdo not increase sinificantl..

Thus, soiils are u.n].ilc(ssl>' ito appreciably im[3a.ct girc'iniKlvyaler,, now w in the ti.uure. Ft:luj ground 'water pmnp aod l:tpe:at system "reniedigiteis1 soils by ;proitecitims against the p'0ie:;rit;ia]iroir ijri(|e:;5iiti.oii of ground water v/hi,ch inay hsive been iln conl ict with sioils. We do not findthese principles to be inapposite,, Elo'wever, 'we >do fijrwJ. a, (jlich'Otonrr in Utie Coniinemtator'sassertions itlwt.:: (a) a.;nse:nj;c is .not e;cpecite<il to significantly desorb lirom \:\m soils, over time (seeFendorf1 Report) and, (b) the Proposed Remedy presents significant hazards toy allo'wing;contaminated soiils to continue lo leach into ttie ground v/ate;r

Mi Ml.

EPA's and WLPSG's continued support for exctivanng unmiurated soiih u a clearacknowhidgmeni that excavation is a superior method by which lo remediate the site.

EPA coiitinuies to support excavation of heavily contaminated unsainrated soils,, These soilsare relatively accessible and, once excavated., meet Utie di:;ilnjiiti.cni of hazardous wastes. EPAdoes not: su.][)]>0]rl: Khe: excava.ition of satiirale:«:l s;oi.!ls. Assuming an e:ffeci:i\ris: ground ivaitei:containment system and soil coveir are in place, exc:av,Eitiion do :s not provide: any additionalprotection of human health and. the environment,.

'WLPSG's own data denwmtmtes that the system is not capmring contaminated ground waterfrom at taut one awa of the Gmmbmv property.. WLPSG has offemt no wpons or daiaindicating thff cvnaitny of the JPfomp and Treat SyMm "i ability xo cap&uw aU of i'ht soil

UR3D3576

comammtnion and other amis in ami around she SIM. WLPSG fails to explain whether thePwrw and Treat System will captim contamination flowing through the: unpredictablelimestone wmronnwn? and how the system mU capture conumwaxion shoidti fhwd&ng orwfosidence of the soil occur.,

The effectiveness of the gromnd water ccnntaijrinnent system iis evaluated, quarterly by ChesterEngineers a.s described iin, tlieir Compliance 'Plan (October 1997). Quarterly results areprovided to EPA. and a.re submitted annually. For a detailed discussion regarding IJtieeffectiveness of the containment system in. its OLHTKIE conrigiaratiion, see Response 111.Fuithex., if it. were: ever determined tliat the: eapuin: ;:on<: no longer encompassed tnoderaielycontaminated soilsv then. it would be manipulated ito do so; either by adjustin;;; ipujrnpijrij;; iratesof existing «/ell:?r oir l:y installing additional well:; as ncc issiEiry.

Tin: theoretical concerns rai;=,i::tl re]2;Eirdin.]i; the certainty thai Utie sysl in is capturing groAwiiter f:n:nn all contaminated air<s:as inKiluuliiijs; itlus: limestone bedrock, exist: equally under both.(he ROD and the Proposed Remedy. ,^s described in Iftesponse lil.ll,, actual! data demonstrates.ttiat the groundwater c(]':ntLi]:itn'ent sysi:ein is operating f;:'[fecKi\Fel>r. Com:erns re:|;ajr'din,[; Inowt:ti«: s>':stem v/ou.ld respond slmouLldL :E1i)odiing or siLib'Siideirico O^KUJC' are addressed in l:::s.][K]H[ise 15,

Because WLPSG ktu not comiuaed the msceswy bestm ., ihtm is cansidwtMe uncertaintyabout $w ability ofxke Proposed Rm&tty ito rwmdiofte tw:miic--a:mUmimted sails, to attaincleanup levels wuifoUshvd in the ®ri$ntil ROD and to b$ proxeativv of human heatoh ami ihetinvmmnwnt. For twaiwipt.*!, 'WLPSG htu ntn conducted tfw arswuc dvsoiptim sututdies itpnivioMsfy ackntrwlvdged H-enr nvcesstwy to adopt I'hti Proposed Amendment, htu notevaluated £h$ tyfficswmw of the propowd sy$imf$ ability to remediate mis in iiw fracnm'zones and htu not conducted necessary risk assessments.

'WLPSG c;{)nc:u.irs v/iUri D'ir . Fendorf 's rLim;lijri|!; ttiai: i:ieso]r];Hix)n rai:es are low. Nevertheless, tinee;(.i3K:l. rate of desotptiion bc orneis. liess significant if ttie routes of e:q>o:s;ure are addressed, aneffective ground 'waiter i;:(]']rilJ3Li]:i:ti]tfE:i]Lit sysl nm iis itn. place, and tine jEji'Ouiiidl 'livatiKi: irc'Sijoraticm.p:;rio;l i:s not lengthened significantly.

.M i\wcri\KX\ in 'Responsie L, the 'Pr-opose l !l :n[ie<3iy wiill rertiediaJDe soils lt>; a.ddir ns.siinja; thus:pcnciritjial roiiil ;s of CJLPOSULEI:: identified by 'EPA., m\d is dierelore ]f»roi:<£:ct:iv«: of lianiriajri iH ailtand the environment:. .Actual (3iata, j3;'enw£:rat.e:i:l as ][>art. (]f tJrte .[[roumdwateir pianup and \mtlsyisienri 'demonstrates, effective {iontELininenit (!i««t ]EijE:sponsc 11.1)., Finally, see Response 11regarding f]:acitu.re ;i:ones an,d 'Resi>onse 18 regarding Risk . ssessrnents.

EPA and WLPSG failed t& identify and evaluate she Proposed Rwmdy under wwnti ARARs.

AR302577

some of which were previously identified in the 1990 ROD. The Proposed K&medy doffx norcompfy with these AJRARf.,

Thus: Proposed Remedy complies, with ARARs. See Responses tiO-62.

Ctmmmil! $4.

In the ROD far OU3f EPA formulated the following objectives for tfw soil/svdimtmts mnffdy:

('!,) Pmtmx human exposure (dermal contact, ingettion,, inhalation) tosoilshvdimeMs having contaminants in concmtranom greater Khan RODrisk-based ievds [Direct Contact Limits., DCLsJ;

(2) Prevent hitman ivxposim (dermal contact, mgestim, Inhalation) to groundwater having comaminants In concentrations greater than MCLs (SO ugt'larsenic and .!> ug/l PCE), whew available, or risk-based cleanup levels;

(3) Prevent niigration (via Heaching) of cofUanwmn^s in soi\L\/sedi\nwm\\ thm$ wcmMremit in ground water cimtawdmtioti in ffxcws of MCLx,, where avaikiblnt ornsk-bcAseti cleanup levds [Principal Threat, Lem's, PTLxJ;

(4) Prevent mignnion of com\:\mimnts in &vM$/s<sdimvM$ (via nmoff, flooding,erosion) or ground water (via gt'Oimd water discharge) that would remit iniwrJiKw-'miMr contamination in excess of tlw more smngeM of the PmnsyhwniaWater Quality Sfami'ards or Federal AlmMent Water Cnteria, whm available;or carcinogmic/m ncardnogenlc risk-based cleanup levds;

(5) Restore gramd water contaminant concentnuions lo the MCLst whmavaihifol&v or .rrt7>i:',»i!)C) ri£rMij!(:/M<:»Hi( lrtJr<:iiff]i:>j>(£>;Hrir fi&k-biwd cleanup levels ay soonas is te-chmcalfy practicable; and

(6) Comi'fy with chemical'Spvafic,, iocaxwn--sp$cijic.t and acti®n\wecific ARARs,including M'CLjs twit. $CRA land disposal nxttruxum1..

The ROD remedy fulfy satisfies the Remedial Otojvcnws. The Proposed Remedy leaves mplace conlaminat&d soifa m excess of mmsdial goals EPA kimiifieti in 1990, which havenever b&w changed.

T\\n Prop(3':s«sd R nn d],' !Jai:is1:ic:s ttie objectives listed above \o i:hc same e :tent as itln:: RODfeinedy, as des(;ii[b<:d bellow:

(1) Under tiie ROD a:rid Proposed IRemedies,, iiusuillalion of a, i:wo-if(X»t soil coverover soil, exceeduig 21 ppni arsenic ]:n'ot;eyc;ts a|j;aii]LSt the poitenilial ibr direcit

AR302578

contact with contaminated soils, In fact,, die Proposed B.e:rnedy 'will satisfy 'thisobjective sooner since in enmih less construction and is more easily and quicklyimplemented...

(2) Uiiudeir the ROD a,nd Proposed Remedies., continued operation and irn.onito:rin||;ol' tins: ground wateir con.taininenit system \v\l\ protect a&ainst t]:ie potential Ibrin[;esi:ion of contaminated ground AMaJter,

(3) "Kinder thus: W.YD .aiu:l l roposeti. teinedies, alii Iriea ily con,taininat:i2:d soiils (widittie: cxc:<:plu)n of n:Ui:.v<::iy small ainounits in ttie saturated, xone on. tJt'ie sit: :]pi'0]>er undeir ll ie il E rpo ed. ]E!js:inedy) \\twM he excavated foir tjre;3itinent,, ;i:s.appropriate, and disposed of of[--sitt:. ]?tj::n:aij:ii]:is; st dls are not expected itoappreciably impact ground water.

Suirraci^: wMfri qualirj' II LS been 'well helo'w tiie sla:rui.ard since tint: ground wai:£:rpurnp and treat: system \w-$\n op ratiLons in. June 199E! C'oiritajrnlnajril insnirface v/;aLteir and =; cl:L[rL£:n:: w.- likely to dcc:r tst: ni'ulc l>:tt:i the [10 D .anid

(5) Under both the EDD and Proposed. ]E!js«ntK(ly,, Kh.i:::n2: iis i[iim: irta.itni:jr i-e a rtiii j; [h$abilicy (3>i' the aquifer to be Hilly restored, llo -ever, as detailed iin. Response 6V':h.i=: i:lE;]j:[:e ol: uncertainty i.s Eiquii' aJL'ent and ii'r dci ieTii .ti Hi, of tJtie Pro]>;)st:(3'Rerric ly ins. unlikely to have an appreciable innpac;t cm, ilie tJLnms: iiranrie necessaryto :re:stO']re tJtic i;i[i:)iiickd water..

(6) .s deiiciriibedl in espouses (50-62, l>oili Rcin.i2:di,i£;s coi:ri]:d;/' with A]K»

Canimmi 115.

Any number of twenty may occur thai woM lead W mvironmtMal dimsiw iftfav toils are leftin place. Tht>$& include flooding,, .ntch as autstid the soil cmttwimtMion on iu leajst flu1iitmamraied mis on \tiw Grumlrim properly , soil mtosidmw, and gvms tmthixpt^tmit: twnts,such MS th& cuimtianv& buildup tmw &wu> fiwn fanning twd fann-mlmtetf. chemicals itMd in the.area..

Ifnide:r' l>oi:li tJtic R.CHi]> sauid lE'rcapois ad 'R(Mrn.i::<;li.is:.s, contanriijriat:<E:(l. soiils will it'eirnaiin ion pbce.. Iltieremedies (Liriei1 cmJiy with :r«:!S.][«!<:i: K> Imow md \\thmt wiils air covered. Thuis, iJtie 'e 'euts.d( SJ:;ril>E:(l. a,bo\'<:: (ri(3<Kiln,]E;, suLbsi.i:lerK;e,, an.i:i influx of faini-related i:!ti«rniK:al,s) "/ouJid he ofc:oucern, uituJler botln ]K.einedles.

Tlie |x)teniitial inip-am of flooding appear to ba.ve beeni naturally contained, hi the past; duruiiig\ hi(;lti tiLtnie, ni,ore "sourKes" were on-siite ai:hd tJtie ^ironirid^^ater pump and itiraal: !>>':s.itein ba,d miyeit bc«:n. ccMusiciiLiciDedi. [ lii ration ol: i ijiritajrnlna.ti.on hias bci;:u liirnitj cl lo die lowlands areas

AR302579

north and east of the creek. Thus, under the: Proposed Remedy, containinaius are luiilikdy lomigrate beyond these past: boundaries. Additionally, pumping of tlie grouiiidwaier haslowered the water itable, thereby decreasing the potential impact tiroirn. future flood events,

Sirnilarly, subsidence is a potential concern under botih Remedies but, o:[' f'xeateir concern underthe EDD Remedy.. In tire event of subsidence o:ri the site, ii: iis likely that tin;: integrity of dieinipemieable ca[> would be sij3;nJ[(icaj[itJ[y coirtporomiseiJt via. sli[iftijrij; ai:id rea]i|!ninent of thelayi ns mihin thu:: cap. In such an. instance, it would be very difficult to rasi:oire IJtie ca];» insuch, a wiaiy as to preserve: it's im]>E:rmnEsabil.ily. ii(3\ve\riE:r, \u\dw title If^iiopcosecl ;Reine<Jly;, lEinysliiftijrijj; of \hs soil cover cajri be easily rectified ib; irepliJOEsnieiu: of die soil covcir in tluait area,follo'H/«<:l b] 1 iregr.Eul.inji;.

Finally, although, extremely unlikely, should constituents; from fanning or other activities.rnigtate 0]ri",site, interactions -would he limited under both reniedies since, under bothremedies, a, lar$e ajrca of die iiite v/iouil<jl lt»e cov«::n :l wiith clean soil!. However., |;i;v<:n tliuait Uiisphenomenon has not heen, cilhseir\p<E:d. previously and that laj:td uw. m thus: ivai:ers.hcd u];i,Ei!tr<ear[) o:fithe: site i,;s l>£:co]rnln.;E; iiniore residential,, this scenario J3|»]>E:,ar,s remote..

Gtnnmmf M.

Before EPA may adopt the proposed mnetty, WLPSG must demonstrate thett xhff Pump andTrm$ System mil remediate ail soils lo be left in place which are: contaminated aboveremedial action limits*. WLPSG has made: no such showing.

As (l.i£:si;:ril>E:d i.:n Reispcjuse ][„ hoth :r««ntiE:(l.ies i nntid.iatis: th«: iwils,, as; clefiiiHE^d by thus: NCP.

Dr. Fendorf has estinmretf thatt if will tikefy takff thousands of years to mmtUatv saturatedsoils via fh& Ptimp awd Treat System, if remediation can be acctwnplished at. all. fnfacf, EPAand xfw Responsible Parties f.mviousfy animated that if 'would Uifw anywhere from IOJXX) lo24. WO yean to renwdiafff the soUs in Ms fashion. No other estimatM has bum given to date./nfact, dtwpite the: imponance. offMs information in evaluating t.h& Proposed Ammdnwnt'scompliance with xfw NCP, no suck estimate1 has been calculated by EPA since 1990.

/is; defined, by the NCP, soils \voi\k\ he: "'nEiniKdiated111 iJin<Jk:r t:lie Proposed fi:einedy ijria|:»pro: ijrn.i3itelly vwo years (vs. appmx. 1:ive 3/ears, foir tJ:ie ROD Remedy). Se:e Response 6{•\m\wdni\l WLPSG's estimate of the ground water re;s,itanil:io:ri peiriod.

AR302580

Neither EP.A nor WLPSG have conducted risk-fatwd mtifyses 'with regard to tfw PwpamtAmeiulment for din*a contact tixposMnw. For example, the Propawd 'Amendment stwfcj; toplace modenixety conuiimina ed soilx on-sittt under a pmwable two-foot soil cover. Thisdiffers sid)siwnialfy from the ROD mmdy which returns pkicmmt of connwiintued saitomtfar an impermeable cop. This cover cannot (be sufficiency proteativv with mpecx tocluldren who may use the ifosr as a park in years w come, EPA and W.KGvs present plan,,,and EPA has not shown it to bv properly protective.

EPA conducted quantitativE: risk. a:5!;c:smie:rn.:; for v^riotis exposure :5cenariio!5 at like sitt:,.inciuding ith.«: j otenitial routes of expoisure vila diirecl: ctontact Aviili soils and ground waiter., .sa result, 'EPA determined that two Ibet: of clean soil adequately prott:cto human, health and tlieenvhonornenl:. 'Th.«: '"iLii sraiJle" ol' this cap {j\r«r the :s;il«: proper was specifically for purposes ofliitnit:in;E; ccmtaict: whdti [[iroiirid water., ratlner tliiiain. tx> pfoviidc: an inn::n;:asE: protectioiri agiaiin st(iiirect contact.. EPA icoicisid'erEHJ. diild.irciri in its ri.sk assessment calculation*;.,

Ctmnmemt .19.

ERA pm'icMtsty 'UMh'he'd a remediation standard of 2.10 ppm for saturated smix. 'Thisstandard hay ntn been changed, and the Pr&pwd Amendment toas fiat considered any studiesthat justify changing EPA'x xtandtmly. TJw Proposed Amendment siwtpty Jmh to nmn EPA's

'To clarilfy, HOppni iis a cljEianupi ciriteiriion, a.is< O'[)];K>!S4;| to ]rc:irn«:diation, slaj[i(ii3Lrd, ]F;wi:tithje:r, tl:ie-!.!.() ]:»[>ni cri.iteri.on. foir sa(iarai.i::i;l soiils w,w> action-isipecific,, meaning that it: appliies sp ;cificallyand. <:mJ.y to tin;: action described iin die R.O1D Remedy.

em! 'Ml

S'onw of WLPSG1 s criticisms «f fc HOD remedy undercut its mm propmaL Ftw instance, ifstmwaied soil amtantiiuiiwn is nai ti ' pnintwy source of ground vnarur c hiwnmithm as EPAli:mi$s, $h&n rainvMw aww$ iihejbmiattwn of laichtne wiUfail to remediate the soil?..

Commm

WLPSG and EPA alkw thai imckfdling vxcamted areas w&th dean fill wndtr the ROD mUonly residt in amtanunation of tin* dean soil. However, if'EPA's soUflmhing remedy iseffvam:,, no Mmcoepuiblti.' conmmintuion of these- stnb will occur,,

A.s&uining; sai:in:ai:ed. soils coulid he excavated, Utie excavation areas could, not; I>E: ide% ai)E:i :(l

113

t30258

indefinitely and Utiuis ,, hackfill soils would be placed prior t:o completing ground w,ateirrestoration. As Utie water table level fluctuated, contaminated ground water would sec:]) hackinto Utie excavation .areas from bedrock and laterally (iom oUtier contaminated areas noi; yetexcavated. Thus, cleajri backfill material would eventuaOy become contaminated, 'EP.Aacl;nowledj3;es that some contamination wi.il remain ijri the sub surface under title two-foot soilcover and does not: expect: the infiltration arid precipitation to retnove all of Utie'contamination. Tlie hackfUIing of clean soils: below the 'water table will not enhance ithecleanup of the site or significantly expedite ithe restoration; of ground watier.

Comment 22.

By wqitinng excavation of off-site unsantrau'd soils and wwMmted orgmicalfy contaminatedso\L\t EPA dearfy aakno\\>k\dge$ excavanon as a necessary and superior method ofremediating t.h$ site..

See Response 10,

Cmmtn'Mti 23..

The Proposed Remedy contemplates a two-foot covgr of common soli. This proposal faifa to-account for the past MM of off-site pwpeny for agriculture awd livestock %fwn$. 'Hie topsailwhich now covers the qff-stie properties ww some of the mosf nutrh*M--rich soils mPennsylvania and perkitipx, the East Coa&t. The xtri.is were ideal for faming activities.Covering the property with a two-fool cover of common soil pwwMs off~si.\& lawdmmmffwnever. using fh& lawd for jfammft agtun, pirmmiin$ any further me qfxhff property,

w both, iitic1 E.OD iaiiid this: P'lropois cl Remedy, a. two-foot soil! cover would be placed overadjacent properties. Thais, this; comment is of limited relevance to the Drairt RODAnneotlirneni:. EPA will rE:(]iiiijr« V'LJf'S r to coorcliLnaite wilh the adjacent ;nro]F>erl>r tov^neirs loinsure that, impacts jams: minimized and properly is restoi-ed appropriately.

Comment. 24.

The EDD for OU3 mmwtfy requires rmedhition of contamimted soils becaiw the soils area source of ground water amtammatwn.. See ROD, p. 16. Because WLPSG is proposmg toleave amhwiinated soih in place rather than vxcavtne them, a mmt demonstrate fhtu f.luf soiare iwt a smrat of gnnmd wiMr cvwummanon and otkwwisg meet the foregoing RemedialObjectives. EPA cannox make this shw'mg.

EPA selected Utie ROD1 JEteinedy Ibr moderately cont^uninal^^l soiils i)a,js< :l on tlieir pntjBiu:ia.l,but yiiLknowo. knpaci: ito ground water. Since the ROD was; signed,, new information, listsrevealed that: (a) the ground waiter contamination appears ito be: riatui'a]:. contamd! iin andaround title site; (1:0 ]:riCMCIe']ra.itely co]ritajrnina.te<J[ soils; i3.:r : uiiliJtcEsly to be a significant lioinrcc: of

AR302582

contamination ito ground water,, no'w or in tlie future; and {<:) Utie presence of soils, hi thesaturated zone ajnd the absence of an impermeable cap Eire: unlikely i:o extend Utie gitound•water restoration period significantly, Both Hie EQD and Ptoposed lELeinedy meet the:Remedial Objectives (isiee Response W).

Ctnmmnti 25*

The Proposed Remedy dtwx not mention the Remt'dM Obje-cxiws. However,, some diyatssiomin ifft.gr proposal ami ax the public meeting (July 1 999) iinpfy that the remedial objectives havechanged, Instead qfanamn$ the Remedial Objectives listed above, WLPSG and EPA nowm$$$si that their $oal is \io contain the contaminant plume. See e. $.., Proposed Rwiwdy pit 8,.No$ only i:,s' Ms ntn one of iffte ofyjectivvis EPA prevhwsfy ukviiijleth but WLPSG and EPAoffer no twpfaiuwhm or diKwmwlttiian concerning the apparent cluing in afojecxhws. Mmconuiinmmt of xfav plume, wen if achieved, is nor the remediation wqmred by the ROD.

The Remedial Objectives have not changed. Botli ijtie R.'Q][> md itlins: !E]lropOE :(l ]E(.i2::rniE:d,iiiE:semploy "coutEiiBnrieint." of soils; Uiis. a nrieajriEi of i:nce:tijfi , tlie: ]ft.en]Ledial Ohjecijves. Both, llieROD and the Proposed ]Eta:inedics eiiri]>loy a ipluaised a];rp]r<>acliL itn> nu:etijrij» Utie Re:rnj;:icliiiaLl(!>bjisscl::iv<=:s; lEccr ]a;rouinclv»'al.er. Sw, !Ei:espon c 14.

Cmnmemt. 'M,

J/'irfe plume is *'$uMffH tu EPA pmits,, this ,nmpfy means thtU arsenic in the §mtwd water ish& soilx they contact.

Tlie p'luiniis: is rp stable " ijri that. i.ts l(]c:at,ii'on and, geographic e;>:t:i2:til: ltia\re not Siift-nifiLcantly cha.ngis:i:li:>v<s:r ise cirai dci:;,a(3ies, and clean soil is :not being ifunther ii:ti]L];»a.c:ite<l Tims: istalyiliit; ' of the plumeindicates that. fudlHMr migration of laLiis.iMii.c iisi noi: occurring. Thus, [jircaind v/atcirE:cintELiniiiatio:n iis coniaine JL an ji is expecttttl lo remain :so i[in<:lcir either remedy. Further, seeResponse 9 re:gajt'dijri([; ilie; e^iliinril: to 'which soils; a;re liikely t(]> be a sii&niiicant 'Siouirce ito ground,water. Fiinally, ]:mnii;Miij!; ajrid. I:rt2:atii:ng gi'ou.irid maw fi'orn hoUti the perimeter and hot-spotwell:i will continue umder botln remedies .

Conmwm 27.

Arsenic cannot be denroyeti.

Agreed. lEMjtrtliHKi', wtmiter botln the ]E(.O1C> i nd FroifKJis^acI Rcirnalk:s, soik contEiniinEili :! wiithairsenic vmiM remain on thus: idle. HoAwwrver, ilic nrieire ]:>t:E:n,i::is: *c>1: jatns iniic; doe*; iriotnece::3!5;3[[il>r iiEKSPiilit in an. unacceptable risk t:o IIULEII^LII health and, Ilie eBvmmnent, sincu:., underbtt'itlii i:eirn.oclk:si, llie:[«: iis; no remaining significant, piiaitliiAWJiy of exposure..

Conwnmi M..

'20

AR302583

As arsenic teaches into the grcwui water from cmtaininawd soils, it is transported to amiadsorbed by other sof.ist 'which it thereby conttmwiates. The arsenic is simply moving fromone place to motfwr. This daes not reduce the volume, umdty w mobility of thecmtamf.nant,y, and does nox consntwv nmedhnion under the NCP.

Under the ROD ]f!.e:rned,y,, the volume of soils contamination will not decrease over time sincecontact between tbe soils artel raii:nJ:al.;l an.d/'or grouindl wafer is; llhniited. In lk;t., tine volume ofcontaminated material will actually increase under ithe EDD ;[lE:iri«dly (Sc«: ][i:iEfS|]<>nus«: 21regarding; recontaniination of backfill nu3itei:ij3Ll)>. Under Utie Proposed Kennedy, sonrieicle&orp'tioti will occur eniiathiiirig nic'tis: j3L:ri3e:rii.e 1:0 \K ]>E:rrn;aLn(;:]rit:ily rEJino' edl from soils via ttie#romnd wateir pmnp ajruiL itreiat: systeoi. Thus, Ihic; RropofHEicl ]?t.i2::rn.i::id>' is preferable with respectto the NCF1 criitEirion of '(Jlliurnis: ircdui:ti.on.

deif holJI-i thwE: ROD and. Proposed ]F!.i;:ine'd.iit:s, a.ir!ieni<: cannot, be destroyed (isee .Res]>on E: 27')and its toxk:ii:y is uualfecited. Under the EDD l :ine(3!y,, arsenic in. uuxleirately co]rita:rn.ina[te<jlsoils, will he largely i[rnrnobi]li7C:d hut not l:n:ated noir reino 'eti. from Uti« sife. H'Cj 'Esvisir, uiidisir1tJtiE: Proposed Remedies;, more arsussnic wiill ultimately be captured by the pump and itreatsystem and thus he irenioved from Utie i;ife. Under botli tbiis: ROD and l:tro]:'0«(M:[ Remedies, UIHE:3:oi:ne' of ground ^^alJEir c:ontaLrninaiti[0]:i Is irioit iE!?c]>E:c:ti :l to lin.cir'i jaLS :, ami. iis likely ito (iecrea.sc; sudrthat, ovcta.ll mobiliity of conta]:riiLna,nt from tin;; site is reduced under both iremediies. SeeResponse I regarding tlie NCP definition oif "remediate."'

t 29.

Neither EPA nor WLPSG have conducted any studies concerning the nwmmt qfarstmicoutsuie. xfw con3: of the plume.

This comment its inn::oirrect. ][>n.;rlnj2[ the pre-design. pliases for tlms: ]rcTn,i;;d>' ;Ecn* C p«::naibl.)s: UnitSix (Gr.roiind'water), e;Ki3E:iu3lv«! sajrnpliing, fesrtiirijg, analyisds;, and modeling wens: coDcluci cl toiE:v;3LhjLat:i;: the speculation an«:l in'O 'eiiieitLt (]•;[' arsenic within, and outride oi Utie illume. Tlie resultsiolf these studies can be found time: Diraifi: lr!sc::ni.i:: SpxE»::ia.itic».n ijri CiroiLindv ater, Operable' Unit Six.Task: Report,, .April, 199,5,.

One of EPA' s Remedial Objectives is to prevent mlgndicm (via leaching) of awumintmu inscnL / sediments tktn? 'would residt in gnntnd water contamination in excess of MCU. Theproposal does not prevent leaching at all ami, in fact encourages leackmg of ctmtammanfsin the soMs/seti'Mn&ntx iMO1 ground waiter in MOW ofMCLs.

risE! ]L4.

C&mwwU 31,

The MCL for arsenic in gwmd water is 50 ppfo. As km$ as xatitnited stnis are left in place,they will be a cominuinft soatrce of ground mntw ammunition ifu eweestf of MCL '.s. Thecummt actmt level for hi$hfy conuimintn&d sat'urated soils aft xlw site is 5 ppm ff'CLP). Fornwt dments, TCLP lewinn r&suits in a conservative $.$.„ high) iisiimatw ofwhtis is likely wleach from. soMs inm ground water. Bawevtr, tw Dr. Fmiorf explains, tfw opposite is inn*for tmmic. Rather, arx\enic--amtwnimued soils with a TCLP of S ppm will almost ttiwaysteach contaminant's in concmt'mtions ,i|ra:H'er than 5 ppm. Accordiftgfy, highty andmadmttdy conmmina^ed saturated soiiy will n&ces,mnfy k'ach conuiminants in ffxcvss of .theMCL of SO ppfo,. and itkw soils are, therefon?,, a c'on£inwi$ source Gfftramti waterconumimition, in dim:x cmrmvewmt ofithe RvnwdM Objectives.

Ifndct ei[tlu;ir ttic1 Ift'DlC) or l3l:r'i;»pH:)sed Reni^ly, tJtiere v^ilJl be ar^EMiiik; in gi^HULiidlw/aiter in exce&iS. cii'tins: 5(]i ppb MCL fyr an <E:jEiJE:ndei:l period (see Response 6). Gmn that and thus: istahil.iity <:»ir the;E;roiLind rater s>':s.itenti (IS SSE: ke!j]>onsE; 24), it is a];»pr(]|)ria,itE: Ibr die ]ProifK>iied l enrie ly to addrssssboth ;E;roundwater ajrid. soil cc»n.Kaii[ii:nationi together. The action llevei for heavily cci[itELini]:La(:c:<:lsoils i:; !i iing/ll 'TCLP arsEinic. In addition, !>ec ]:!.<::='[>onsE: 9 rsij j'din ; lJ:iE: extent to 'which isoilsare a "source" of arsenic; to ]E;rotind water. Tim use of TCLP data from, soils samples is justone of many JLruilicaitoirs thai: soills an:; :not a siginficaint SOIH E: to gioiurid water.

Ctmnmenti 32.

EPA and WLPSG stum to ar ue that iir hi qfno- cons&qiiMncig that tlw soil r.x a soumt ofground mitsr contanunation. Tl'uy todkw thott ttlw P*ump ami Treat System wiM capnm ail ofthe ccmtamittaxed gnwnd water so that lit awiwt reach potential reaqntm. However,mmrdfosx of "'capture"1 arvu'tne'nts, the Machine: vioititey the Reinedial. Objective!', which havei - r » ' [ ' - ' ' C J t •

not bffffn and are not proposed w be changed.

To i:hc: i:on::rciry. it: iis of great consequence ttiai: isoiJls do nol a];ipcai:r \o tic a significant, sourceto [[round water (see Response 9).. it Ions: importantly,, tins: presence or iai'bsence ofcontanii.:nal:ed soils, app^ears i:loE;s not appear 1:0 si]a;nJLfi(:anitl>p impact the predicted ground.waterirc^toraiticni pMg:ri(]N:L, Further, bath, tlu: EffD and i3'ropouE>d, IJteimc^hii rely ii]?K)n itlinEt ground 'waterpuitnp ar l tj:eaiit siystem to ciaiptLnre j2;r<:HJLnd wnutr prior to its. reaching potential receptors.Thus,, this Issntic: has 'limited,, if any, irdevan.ee ito Utie ROD A.rnendmien.1:. Fimlly, t3otl:irE:ine<Jlic:!s meet the ftennedia.! C)l:>jc:c;t.iiveis, (swse Reisiponse 14).

Cmmtent 33.

It is timpfy not xrmf thai the highfy and inodmnety cowtamintittfd saturated wils are withinthe capture wne ofxlw Fltwtp and Tnmi SyMwn. As Mr. Km$ poiwts ml, thv hydmidicgmdient tu Mw site,, drawn from WLPSG's own data, indicates that the Pttmp and TreatSyslm has noi captured the consummated ground water ahm$ the northern innmdtuy of theCreek at all See King Report,

AR302585

Tlie heavily Gontajrninaied soils are almost entirely on the site, which is surrounded hy wells.Therefore, it is virtually impossible that these soils are outside the capture zone. As; detailedin Response 11.1, it appears that certain, wells were omitted from. Dr. King's analysis. EPA,whih the assistance of the United Suites Geological. Survey (USGSK will! continue to overseethe ground water remediation to ensure that all heavily and mocleirajtely contaminated soils arcwithin tlie capture zone.

.r"y , *>

The pump and treat sryshm -would need to operate m perpetuity to ensure tkwt mis 'teachingctmtanwwirJls imo the ground water are remediated to M'CLs, tfw standard set forth in theRemedial Objectives, especially in light of wtiintiU's that a will take thommds ofyetm toremediate the soils via the Pump and Treat System.,

See IRespoiLse I lugajrdlim^ ihs deiFkiiition ol' "remediate/ B.esponsc 6 regai'diLng litie j|;:roundwatjKr ;n siC(]faticni |>E:ncd, md IResponse 14 rej^arcliing thus: P'lropCfS^icl Remedy's ability 1:0 ineei;uhe Remedial Objectives.

Connwimatton will continue to leach from the so&h into ground water unl&ss ami until thesolh are .removed. .Accordingly, twcavatifig t.h& soUis> to bedwd: under the cumnt ROD istwcessary.

6 arKl 9.

Com m ml 36.

Thin there is a "snM? plume" does nat mean that contaminants -are not faeinft transposedfrom one area to another or that, tfw plume, may not, at some rime. In the fitiim, becomeum'tafolff. 'indeed, further imwceptablv soil coraaminaiion is likely occurring due to contactwith contaminated ground 'water. Kn addition, ike. piiune. may be desu\bili7.ed by a nuwifow offactors, such as fry &xamuing imstuimiwd mis, by the influx of phosphates from farmingoperation runoff or fry .flooding of tkv .me, which is believed &o- have caused f,h& widexpreadomianunatwn on much of the area m the fin".! place.

See Responses 1!i,, 26, and 2S!,

Comment 37.

To date, zhm has been no major desorp'Sion ofanwnic at the xii'e. Over time, th&inimimion of competing ammic smbmts xuch as phosphau'., sulfcun or carbonate, from thecumulative runoff fo'om, mtit'hy agrio*ilnml prop$nm may comtiniu* rt $wss anthropogwuc

>'\ c\ r\ j"1 (-) (".: IJ,:::!;: i:i (:>

introductions into the. emnwtmMU wwtiing in catastrophic rdeases Gfammfa: outside thecapture wne mdfaihm? of the Pump and Treat System.

flee Response 15.

Commmi 38.

WLPSG is likvty to arguv, ay they have been Jormuting for the law ten yetm, that iir is'teahmcaKy i^vmctktMv ito remediate the $mmd water to the applicable xUwdard of $0 ppfo.However, 'WLPSG xhmUd not in* abk: Ho bootstrap an argument of technical impTarticatriiiryonto a remedial effon thatfaih to rmow Mn» source? of ground watffr cowMmination, therebyiml'ang suocessjM ground water remediation impowibie.

WLKG has not: c:'a]['Lia.tES(3, Ktie t :chjriic;3L'l {jra,i:ti,cah'iiliit>' of irCiisitHicijin; the aquifer ajrid. dk)(Mi not,expect: ito prior 1:0 tJtiE: tirne iirarrie. rEH iijri il 'undct Utie Ol)' Six Work. Plajri (lEive yairsi).. A&d<Msc:rih :d ijri RC:!S|»O][ISE: (>, iirKl«::r' !>:>(]t:i this: !!M!)']D and Proposed Reirnedy, (]:IE; [sronnnid water is notexpected to be restored for many., ni&ny years. Tlruus.,, t]:w; 'l- rioposed lljEMiriediy satisliies ttus:NiC\? (:ri.itE!ri.;ai ibr ireirnecly :selE;cl:io:ri.

Comment. 3$..

How will the Proposed Remedy meet the dmnup objective ofprvvmting migration ofcontaminants to mrface-water m worn of applicable cnltma of risk-bawd cleanup ieveils.

!ik:e ]ft.iE:sp<:nus : l.!5. 'Further,, grouindi wai3E:r iis treat:i£:d to meet a.pplicahle isinirlace wiaiteir diiscliajrgelimits esiaiblLislinEi'd, l:»y PABEP.. E,:E1:luen.t has he:en. wdl Ai/iitlnin these limits tor tJt'ie duratiKjn ofoperations.

Comment 40.

The proposed h*imp and Tmn Sy&twn mU ntn prmvnt mignnion oftke soils and .wdwimtsvia mnoff', flooding w emion, atul WLKG hay neglected itw atddresx how the Pump andTnvaf SyMm will pmvait migration of amttminatwn mmtoing from these naturalocaimncey. The nimtrmS. of the bulk of the co iiamma d ml now mfattantuilly decrenwsthe risk of spread of the contamiiuinon shoukl the Pump and Treat $!>y$tem ftul or flooding orsubsidence occur.

See :Eles|X)]iM: liS,

Commmt 4L

Tfam hay bm\ no demonstration that thv Proposed Amendment provides ceruiinty, rdkibiliryand adt'qmtv safeguards to protect human health and \tiw mvirmmmt b\mui$e WLPSG htu

AR302587

neglected to evaluat?. crucial Jnaors and perform the requisite scientific similes needed todwnonstmw the efficacy of the proposed remedy.

Comment 42.

A number of events may occur winch would result in 'MwfaMsmt of the remedial action twproposed: For e\:ampk\, floods and the influx wf phosphates and other chemicals p-om fanningoperation nmoff'wtnild mobilize arsenic in th<K soils (xauirated and unyaturaxed)..

See Response 15.

Ctmm\mit 43.

EPA recognized th& Pump and Treats fyMem's mabUUy w fulfill ffw Remedial Objective's whenh evaluated 'WLPSG1' s soil, flmhmg alternative in 1990 A't that rime, EPA undemowd ' thaf"then* is a significant risk that somff of the kaching solution would escape the w&il capturenetwork (becaase of the stiff's complex hydrogvoiogy) and contaminate dovvn$mdhM gromdwitw.. " This risk st&U &wty today..

SincE; tlite ROD was signn2:d ijri 1WO, new iirironnal.ikjn on the site has; demonstrated lliai: ithecontaminant plume ii,s naUiralily contaijried! ajrid. tJriat: soil.;?; do not: appear it(]' I>E; ;s;i[»iiiifi,c:an.tl>FinipicLCting .['round water (see Response 9), Thus, EFA"s concerns; relating to die "soil.illushiin.!' alternative" have largely Iw&n. addressed. Fiirtta,, x® l eiipo sie 2*1- ire|2[ar{l.iLnja;:s.ijg]ni;fi:cant n«:'M/ iiriforrria.ticm tJtial: HIIEIS 'tx:e:n obtained about: ithe she since 1990,

WLPSG miMX conduct d&sorpf.ion rate smdies -to justify tis proposal. In its OU6 Work Pirn,WLPSG property asswtx that dewrpxion mte xs fwedvd to determine, the length of time, if willtafw to remediate rhv soil.. The cleanup of sorted arsenic am be imntffd by wither xhv rate axwhich ground wafer can be removed from. the. aqidfer or the rate GM which arswuc dworbsffwn the aquifer solids. The efficacy of the proposal largely depends on this data.N&wrth$ivs.$t neixfwr WLPSG or EPA did this retting,,

Skifficiient da.ta exists; wichoui: desoiption suuiies to clE;i:<;:[:rn.inn=: th,i3.t tine l]ln:>[]«:»se(3. ]f!.(2:rned)r isiinliikely 1:0 significantly lengthen the pouind v/iaiteir rKstoreitiion pmwi (s«:e R«:;s|K]]riSE: 6).

mtt 44..

WLPSG tmwit demonstrate, tht* .Imgfh of time funded to numditM the, Muls via xfw Pump andTreat ftystwn in order to support its proposal. EPA has admitted that it htu mvw estimaivdthe length of wmffdiatim trf$w moils via the Pwnp and Treat &y$tm.

AR302588

See :Responsie 6.

Comment 45,.

The NCP does not permit trial and error methodology, but rather, requires relhMliiy amicertainly when contaminated sails are to be left in place. EPA and WLPSCrsfaMure toconduct necevsary scientific stMt&is and to tnhMwise. demonstrate rhe reluMliiy aiui ceruuniyof'tkv Proposed Amendment dtw not fulfill the NCP reqummems, Due to the uncertaintyconamimn' $i&veml fwvinmt wivntifk variables, the xltw presents a highly rMy .ntmitimreatfy to explode shtwSd the Proposed Anw.ndm.em he Implemented.

In fact, the NC!'P requires that remedies bs: re-evaluated, every five years to confirmeffectiveness. In addition, see Response: 2 regarding the reliability and. ceirteiiiity of tins:Proposed Remedy .

The ROD Remedy prmeius generation of Smcktifre by consolickuin wnfam\\u\t\vd wihan 'impermeable cap. tfxcamtiim the stmmitwd soih: and placing (hem M&OW! itfw ground waitertable under the ROD eliminates the risk thai ike ground water will rise- and result II.M iarn$pulses of (3!,rp.s'iE7ii:it; wleuses pwn the soil it contacts.. An impenneablv cap aiso obviates the risk'thai tmwiif: contamination will spread in. the failure as a remit of ficwdmfi (or] subsittoia* orthe influx qf chemicals in nmoff'.

A:ri iiiip<E:rrni<^al:ile cap :\QM> n.-:H. ]:»r<E;vi;::nt isoih froin cnmuijj, i.ti c:c>nt3ici wilh <[;r(]HLinicl watci: clurint;flood i HE; (.=,ir,C£: ihv, 'wa.teir tal)l.<E: would likely ri.se' u:nd.er i:t»: cap]1. ai:td leiaLcli ite could hegenerated i:liJLring this instance. FiurtlH:!; duirinia; periods (]!' lii;[;h ]pi'iE;c:i|>itat:iion, ]:ui,rnpijrLj» JTouri\ el.ls would no doubt i:nc:reiEise., i[)r(3'An.dijri|[; furilier ctintaiLmirierit of tl:ie ;[;r(]iind waiter, See:.E:!ip<niL ;: ].!i' ]fi].:rth.e::r' regarding flcod.iri.E; .and =ul: =K!<: ru:c

Comment 47.,

There is no rational basis upon which EPA. dei'mnined that wmmnim of mod rai'dy andhighfy conminmn'eti' saturated soil's would be UK* costly ami U'chnicaUy difficult..

'Tins; determination itluait E:;<:ca\'al::i(3>]ri of .saturated 'soils, would be technically itiopiraciticahk: 'was;I>i3i:s;ed on iJtie folilo^viji:

Tin;: ]lar||;is: 'vo'hjLrnns: of ground yvaiJEir tha.t -wwlA witi to be: pumped to dewata1soils,, iELSsurniiig it i:s; even pois-siiMe;

Tltie d.:if["k:iJilt:ies t]riat vvmld been i£:ticcuinteire:i;l -[hiring '£:3tCi3Lva,tion, even, assumingtlu3it d :M/a.tE:ri.!ti|]; \wt achieved, from -working wiiJtiin ti| ht c;oi:fcdiLti.)C)iius; (d.ius to tlinE:

ftR302589

extremely small excavation areas that could foe open at any one time lo limitthe vohnne of pumped water), moving equipment, and handling wet soiiis;

1 The: enoirmous diifficultks that would foe encountered in diverting significantlengths of the 'Pulpeliccketi. Cireek:;

11 Hie impact: tha.t 'would occur to Hie aquatic environment within TulpehockenC!:reek: during diversion and as a result of excavation.;

« The difficulties; iin accommodating the excavated wills; on.--sii:e, where it isestimated tJtiat die: overall site elevation would iriise by 15-20 ifeeit; and;,

11 The project duration.,, estimated to be; two 1:0 three tiineis. longer thanimplementation, of the Proposed Heine'dy.

AA. best oven;:onii:rij2[ the;s;e itectindcaJI difficulties is theoretically possible, huil to do so isimpractical and unnecessary considering then, llie ROD1 ]Elj£:nited.>p itias virtually :no beiKfit ovei1-he Proposed Remedy and. has sigtiifiieani dia:wbac;k;Si. The ROD ]El.einiE:d>r is not moreprotective of human health and the environment and. may be less sio; will have a greaterirnpaci: on die aquatic environment and community; will not significantly reduce the: groundwater restoration period; leaves so:rnev/ha,t more arsenic: on-siite indefinitely; severely impacts;and possibly destroys the U;riion Canal and Lode:; iiE:nders itlns: siite practic aill)' usekss alterinnplenieoiation,; an<:l is much more costly to implement.,.

Comment 4S.

EPA achnmiedftvd tfatit, to properly evaluate the Proposed Amendment, it. would wed todeiennimi' the: ability of this Phimp and Treat System nv farther lower the wafer tatolg so thai allhighfy and modvratdy consmmmtzwd soils would no longer be mtur&wd. Lowering zhv watertafrle would ihvmby alleviate IVL'KG's alleged concerns regarding ffxctnwtiofi of saturatedsoih.

Tims: 'wai:er tah'le l]i;ais lfc»e<jiri io /< [is»cl Ifour i:t) si:n; fasit siixe puLrnpijri||; l>E:j|a:ri in June I'S)9H.. I'rii.is.ha.s had. Oie positi\pE: effisx:! c»1' i]ru:rea;:s;in]E; tJ:ie volutniuE: of soils lliat Ciairi he; excavated,, therebyreducing; the i/iolimrieji of heavily contaLrniniELtei:! sialuiriaLted isoilsi \.o veiry jsrnall p'iroporti.cnis..liluririE; tiiis period, all wells 'weire pturnped at maximum pile:; possible., ]E)rav»'d(;»vn leveledolT raiihei1 (]!iLii.c;l;J!y ai:Kl appears, to have: been limited more by llie t o- ear drouj n. iluin bypinn.pij»|f;. Thus, iit is luinhly iLinliJkelly tJliai: ulie current s>'.stei:ri cai:i bs: used to (Jkiv/ateir soils

mf 49..

The F^iwp and Treat Stystm htu already lowered the ground vvawr fable by approx'mmidy

AR30259

ninety percent by pumping tn a rate of fOOppm... The Pump and Treat System ha$ the abilityof pimping ike water at a higher rate to furtfwr tower the water table.

Tim conclusion is; a.n iiiLEiccijiratc interpretation of Dr. Kiin 's report , in which 1ms: stated tliat"90 percent oi ths: highly (emphasis added) coritEuninated soil [has hoen] dewaWEid." WeCOIICUM: with 'Dr., Ku\g generally and believe this. is further evidence that the Pioposied. Remedywill remove nearly all of the heavily contaminated gKOils (See Responses 7 and 13.)..

Comment Sil.

WLPSG must MttifoUxh whether or not the uw of oxidizing. ag$ntv- or other chemical can beused to promote anemc dvsorption into gwmti VMM: The proposal states that WLPSG willnot complete such smdm tmiil the design xtaftff of the altenunive, remedy. This means thtuWLPSG Us mcenain whether accderaxed anwnic dissolution is even possible. Given theimportance of dissohtfion to the gffeMiwumss of the proposed remetfy, EP.A cannot Imw adecision no amend the ROD on the met •$ pnwmstf of flintier poi iMe J'«i>t|j'.

This ISSULE: h;3.:=. iLiniiicd. si.giiLii cajrice: t:o i'E:n:iE:(J.y seleci.itMi sin:;f: i]:is:rE: is alrea,dy a gr Ltei:] ikelihotxl that, ajrsenic can be desoTbed fi'orn inoilcira1 :] y aonurniraujd soils; under ithelE'tctp'CtsEuii tennedy,. Ilius, thie 'use w[ a]a;ents to enhance 'desorptiou willl onJty i«;n:ase IJtiea'd.Arin:ita.]E;es (]i l]t:te 'Proposed ]K.einedy., V/][JE'S(!3f iiniE:n*[l!i lo complete this exeir<:ii:s;e dn.:riii.]a; desi.!E;nil[ the Proposed i Esniedy i.s selis ;lii!!icL

Gtnnimnf. SL

EPA and WLPSG have twunwd thai' ir/i.isr on- and off-site contaminated softs tm in a state ofequilibrium, when infaa. Mwy are in a consiwn $>ttM& of flux, In addition, the mtmuitv of the-mawnum arsmlc retention capacity <:>/c soils is htuvd on M mcorrcctty tipped equation, andthe methodology tmd to predict ?.lw teachability oftmvnicfhnn soiLv ix incorrect.. Withoutaccurate mmiific injlmmt wn, the rate ofarxenh: demotion cannot iw pr&diated, WLPSGand EPA haw, provided absolutely no data cQm:wnin$ the sedation ofanwnic or thesolid-phases to which they aw asstmtitted. BtwaiMw dijfewrif fonm of-tmmc react distinctly,.spvdatum ito neceyxaiy to dMrmm? how midity arsenic w$U destwfo into* unwind WMW or howthe tmenic will react to w:idtiw$ processes and thmrfbrw whether or not the ProposedAmendment' will remediate the menic in the .wtiimtard soil at and near the site viafltMhmg.

I'he: referenced sitn.di.es (conducittid. over ton. years ;aj[,o)i ll"ia\'e lijrnjite l, if any., isljsnifieance l:on;:iniE:(]y seli ;:l,iLon siineu: soils do not: a.pps:ar t(]i be a significant, souice t<3' ground wausnr bm&tl onacrua.! s;it:is: clatEi '(s«is: ]EljE:spcnuie: 9). The: isisiLie of ajrsenic !si>E:ci[iaitiLon iis knpoiMani: iprinrunriJly i.irit«:rni!S. of einsuiing Khait thus: ;E;roi:un:l 'Winter pump ajrid. t:ris:.ai sy:s.itenri c;an el1 c:t:lvi2;ly nrieet <:li.i :hajr]3;eaiteicta. Gri\r'E:n i:tiaJ: boith. tJtie ROD \u\d Ptopcisedi ]Ei.en:ie<ily inc:lutl.c: ttie gic'cmrtcl water pump andi:['eat]rn«E:n,i: system (and that, tie sysiiBin ha,:3 |]NS«:I:I well v/itJtiijri idijsc^iairgist Hmiis), the issue ofspeciai:io:n appe;3:r:3 to have little nEile ance t:o the l>ralt 'KiJD

'28

HR3Q259

Cammmt 52,,

The Proposed Amendment is mhmviffy inctmnsttmt.. White claiming that the- conrammtedsaturated soils will not be a source of future groimd water a:mUiminaiion,, EP.A ami WLPSGproffer thai the soils will be renwdiated through th& Pump and Twin System by capturinganmic which leaches from the soils im® the gmmf water, EPA and WLPSG fail to explainhow nhff Pump and Ttmt $y$<tm mil dean the soils by capturing teaching arsenic ifws&nic isnot leaching from th& soils into xfw ground mtfw m the first place, 'llw Inconsistencyhighlights the flawed logic behind tfav. proposal

See Response 9.

Commmt 53,

When if evaluated the Proposed Rmetty m J990, EPA determined ttfun\. using she re pomiblc.parties1 own caladations, it would take W,WO to 241000 yean'for sails \o be clawed up .toa point where their leackaw concemradon would meet MCLs. EPA does not now offer anynew mfonntuion concerning the length of time needed $& Main the requwe cleanup goals.Further, EPA dews not now question ifhv ability of the Pimp ami Treat Sysfwn to renwdiafethe soli's in any reasonable and acceptable amount, off me.

S;:E: Response:= I, 6, and M

EPA and WLPSG htnwjmted to address the risks related to leaving all saturated soils inpiacff and comoUdatmg all m&detmldy conlaminaied excavated soils on-siM wider apenweaMt? cover. Leaving saturated mils in place promows continuous contamination of theground water while consoMating amtaminated soUs on-sit$ under a permeable cover onlypromotes reconu minanon, oftnhtiroti- and off-she areas should floodingf subsidence or the.hrflm: of chemicals occur.

See lELesponsesi 9,, 1.5, and LSI.

EPA and WLPSG mmt conduct a rh±--bawd twafysis of direct contact risks, because tin*Proposed Ammt^mt pwpwses x& f tivff conUimimned soils in place wukr a two-foal soilcover in an area it proposes cM'idnm skoidd mv as a park.

See: Response T&.

AR302592

The imroducnon of competing mimic sorbents swh as phosphate pwn a^nadtural practicesam lead to etthanced, intt unpredictable arsemc ikxorption, Lf&ewhw, periods ofhi$hrainfall am came local anoxia tmd also encourage the rdeaw, of arsenic. Indeed, floodingofxfw lifts' presimabfy caused ike spread ofan&nc to off-site amtis. h amnot be predictedwhen tfw&e potentiaHy catastrophic events will occur ami they cannoti be controlled. Theion$~\erm \mavna\my a$,wcuUed with land disposal1, h .nmpfy one of several issuer EPA hayfailed to address, but which intifav the PYopowd .Amendment unacceptable under the NCP.

See Response 115.

Comment 57.

EPA rm&n nwivw and WLPSG must jmtify its pwpoml with scientific cmduswm that kmincontamimtetf soiLv in place does not pose an unacceptable risk to human health and theenvironment. WLPSG has not conducted mch mfc-ihwsed anatys&s.

lilee. ]ft.<sisi[)cnis<;: \l\.

Commenti 5fl'..

hi 1990 when EPA evaluated the responsible parties ' proposed soil flushing remedy, EPA wawry concerned with the. remedy's- inability xo meet insk-fotwffd MandMnis, EPAV'xfirihm t-onow require: WLPSG Ui provuk1 JBWC/J analyses concerning risfc-Jhtisvd Mtantiardv is puzzling,and the. proposal without such information toidto any reasonable basis.

!5e£: R(::=i:K]:rist:s 18 Eind 13.

nt 59.

EPA, fiuls to assess the Img-tmn maintenance cants of the proposed mnedy and the potentialforfunm remedial costs should the proposed remedy faU, bath of which tire iwe$.wn$nts EP.Antitst make mdvr CERCLA. EPA and WLPSG only acknowledge I'htn ihv pmposed rmetfywill have to be evaluated after five years to detenninv its effectiivmeM, 'which, dearly su$iiett$that EPA tmd 'WLPSG are pnipwsini* to tak<e, a "trial and tnror" approach, Gmn theuna'riW'ity of the yffi:cth>envs$ of the renmty,, thv Proposed Amendment tfot>s not meet NCP

Eoih ithiisi "RiJD and, Pr(]p<;is-sjd, Ift-i rnis liies; irely upon 'the soil cover IMKJL jajrcmnd 'W HDESI: ][HJin|» ancll:[is:.al3cn.«rnl: system t:o llie sarru: d^fiiree. 'Iliuis, ll ie issui;: of "lailiJinK" pertains to both, andiaippears to have Ikrnited retevance 1:0 the ROD Amendment See Response 45 rejajardlng itheMCP ri2:quii]:e]:rient: for remedy review,, 'which i.s required urider eitksr i:h.e EffD or F'toposedReirnecly. Finrtlie:!1, SE:C Ifcesiponse 2 irej^inlkng c«::[itaijr»ryr ol: itlie ir'eniis:':l>r. FiriEilly, O'/lVl cost^swill b«: less; iLindeic Utie Proposed 'Remedy since annual costs for impermeable c Eipus ajre: ty|3'it:a,]il>'

greater ilian ibr soils covers;. 0/N1[ costs; for tlie pumip and treat system will be the siamelender both, remedies.

Conmtmt &&.,

The: ROD identifies the RCRti landfill closure regulations as an ARAR, As a rem't, the RODrequires that the capping of moderately contawdmwd mls/sedwwnu on-slte mim* meet, skewregulation.

In tin;; ROD, the references to RC'Rj\ are actkni-spEid.fk; mil would not .apply to die Proposed^Remedy,,

Ctnwnmt til..

'll\e proposed Amendment violates 40 C.F.R. 268,38 ('which Ptmmytvania also hay adoptedrhnnigh inawptmztion by refe.rv.nce), which pmfnbits land disposal of arsenic above J pptn(TCLP), As explained before., leaving highly a:m£amimwd uiUimteel. soils in place, violatesMs ARAR at the site.

RCRA. reqiiiLiisitmeiuts; for dispoisal wo\M. apply o:ril)r lo soils that actually leave Utie site (asopposed to soils that are being moved oir "consolidated1" within the site)

Comment <S'2.

EPA and WLPSG have not identified Pennsylvania fs Clean Fill Policy (ike "Policy') tu mAMR or TBC item, and the proposal dearly vwiafff.$. this Policy. Tfa<s P&fhy, eMabtisfml inaccordance with the Solid Warn' Mana m&ni Act and the Pennsylvania Clean $>mwm Law,prohibits imn$ mis ax clam fill' awttwiinated mih arsmuc in cmcwnrations greater thanthree ppm.

EPA. arid P,<U!>EP disaissecl tlmEs ap'proi riai nn ss of Penorisy]lvaiiia.",$; ("!leaj» Filll Policy and havedetermined that it iis neither an /iR/lR nor TBC i\\im.

EPA claims that under the ROD mmtfy,, dean sails used to fill excavated amu1 bdow thegmtwd water taMe will foeconw. reamt imifuited by the. ground water. However, iftfw Pumpami Treat- SyMm'sfiMshin inwh&d works, as EPA ami WLPSG repmvnt, thm will be.minimal r$conumimit.ion of thv dean soils, and significant amcentran'om' ofh^hly andmodvratdy confamimted scnls mU be replaced by m&mttmxntu&d or very

inalvd xoih.

See ]?t.(2:S]po:ri!»e 2,1.

R 3 02 5 91*

EPA and WLPSG have failed to- consider that iir is quite plausible so reduce backfilla:mniminanon ty usinn baa\fUi with a low panitionmg coefficient, such tu stticvcnts sand orcalcic/dolomite, winch is prevalmi in the area. Using thvs'ff materials as dean fill willprevent omuwmtnion,, (fit occurs, itf conctmtratiom above, remedial action lewis.

'Even if the backfill! soiils ba.ve very low partitioning cwflkieiMi,, ground water -within. llie•pore volumes in l;tia,i; irn.i3Lteri.J3Ll will :re:mLain co-ntaLniiiiiated. A:ny remedy ijri which formerlyclean material coirues iin. contact \vkh coiiLitEiniiLnatiCHi ground \\r'<\\&[' would ;3.p]>;:Eii- ric'i to saii:;fyttie: NCP's ;[)referei]icE; for :r ::rnLedles that: resell; itn a irediucti*]'!! in volume oir nnobiJlhy,,particnjL'lajrly v/lrien theire: app^tars ito I>E: no benefit im doing so.

Canimt'iit 65.

The mnoval of the: currently matumt&tt saiSj dimimnes a jutim source of ground VMHWwnXtmiinatim.. As previously explained, unless ami mtil the sautnwed sml aw; nmwved, theywiU continue to be a source of groimd muer ctmtamiiKiiion.

•SieEs Respons-E: 6,,

Comment CiiSL

EPA. and WLPSG egmss concerns about tlw m&d to w-nmtff the Tidpwhocken Creek anti wdismantle ihv Union Caiuil. They aho <Rxpr\$!S$ concern about the impact ut wetlands shouldthey implement ih$ ROD. EPA ami 'WLPSG admit ufaM rh$s& concerns are, iwciikniw1.. Many event, under both \he ROD and tfw Proposed Ammtilnimi, if/iisp Owd: would n&ffd to bvni-rouied, Re-routing of the Cmfc can. {ye ttcamiplLihed with proper engmennii, such as i:sm-ed at ttil Sup rfund .utes \o achieve NCP - required remediation.

Tlie: T'lLilpelKjeken CnE»ek vould iinkclisrrjE; !3iL,[S][iifi,c:;ain.iL r more ire-rouiirija; ajKJ, (Jlisturtiajrice UL:ri(31erthe ROD1 Kennedy thain. ULtuJk;!1 iLlic: ][|ircrpos«!(3i lElenciecily and,, itlie; Union C'aiMil anid IxjcJk \rn\M|]NE: ;s :ve:;r1le;/ i:rn Hi<:ite<i a:ru3i j O'SsJLbly destroyed. ]tinj;ii:nee:rii:nja; eoiiLtrols (;a:ni]LOt: ellinriinatis: itlioseiL:rnipa,cts, ILJn^ler thus: <::rilis::tia,. the Proposed ]ElE:n:ie<3iy is pireierabi'le to 'tins: B.O1D :[i:::cins>cl;y'.

Comment 67.

EPA and MJWG's? amtwmy 'wtainn to the Cwk are pnmisvd mi \*hv knight of.MUmnedstnh' 10 be excavated mdvr Mw ROD. However, EPA ami WLPSG1 s n reumtaiitmy thai thettiicknew of stiXumtwd mis may be aver\f{fteen fevt Us .inaccurate and purdy . ciikitw:.. .Asta mm. site ddineation maps indicate, Miff thickness of sattumted soil? in offaiw area? when?erxavatian is wqiared by the. ROD is $ffn&mUy k:w than four orfivt'fM.

£!>i:iinai:e<; of the saturated thickness of soiils 'were developed by overlaying bedrockcontour-maps u/itli water table inlbrmation (December 1998) provided by Qiester Engineers,and range from 4 to 15 feet.

Ctmmmt 68,.

Any potential impact to wetlands from excavation is outweighed by .tkv continuedcontamination of and tkmit to th>s mniandsfrom leaving contaminated saturated .mis inplace. In any event, as ERA comedy wotes., th&w Impacts can b& mitigated during xitwrestoration. nuts, EPA and WLPSG1 s awiams rdatvd to MH? Creek, Union Canal amiwetlands are no htws far amending the ROD.

Impacts to wetlands, the 'Creek, and. title C' na! are important factors but certainly mot the onlycoirisideira.ition.J3 i:n recommending thus: Ftoposed K.emedy. See Response §6 regaidimgmitigation of ithesie impacUi,

t 69,

EPA and WLPSG ex.pre'sx concerns thtu 30 million gallons of'WQMwaur nmy be gmemieddunng excavation of com *amim\\vd soils. EPA and WLPSG have tifoo tmpnwx&d concern ihatground 'water will infiltrate, into excawMion areas when the sautrtned saifa1 are removed., Firstthe estimate is admittedly a high-end estimate. A\ho, !.\ is mkntywn undt'r what conditionssuch a high-end volume of vvaMwater might, be iiwnmifed.. However; WLPSG am address itsconcerns by farther lowering the muter table.

As described in, WLPKi's coirresixmdeocre 1,0 EPA (Aug. 27, 1W9)1( tins: estimate of 30million, gallons (MGj v/;ats based on a. number of a.s£uin[>tiou; n:j;,3.n;[i:rij; ]:'Lir:i[] in;;; mtt:s,i:ons;t]'iJn::t]LC)n perii'Odsi, elj;:. Thws: 30 MG' estinnat^ is a conservative number., not a high-endestimate, as detailed ini t-tie Aug. 27 correspondence, su.ibjisici: l:o considerable 'vaxiaLti.on (up orclt>'«'ni) depending on U:te .ac;Uial conidi.iticniji encountered. Sat Response 4B iregarding loweringthe water itab'le Iruirljher.

CommieM 'Ml

The mtnmmf, plain is ded$m.d to accomm.od:itv tfw mutwal&r over the Mven-mtmxha:\nstmction pmati estimau'd by Environ for excavating Mw sails. By f.ncm:isin$ theoperating lime of the P^imp ami Tretu System to dewatw the sauirated soihpwn ten hours totvwnty-faitr hours a day, tu1 is standard practice, at any ,me,, phasing tfw excavation amidecreasing tfw excavation iriw\, the Pump- and Treat System can easily accomnwaktiff 'die 30million gaUom of \mstewt\ter predicted to be gmmitedfnm the miwawd soiils.

See: Responses 47 and 4.f!, Further, increasing pinnphig 7A hiowirs/djaiy w/ould. only inn::n£:asE: tl:iewater to l>s: geiriEM-ated from 3Cl MG 1:0 12 MG.

flR302596

]WLPSG and EPA should have wddremd its dewutenn$ concern when they deigned thetretumeni plain, because Xhey knew at that time that tluy were rvqirintd to excavate anddewafer all modmitdy contaminated soils.

lit is theoretically feasible to construct EL treatment plant. \M$V enough to handle any '[\mv thatmay be encountered., flloweveir; at. the time the sine treatment pliant -wajs, teipittl., as; now, iitwould ha.ve been extremely diffiicLilit to pnsHliict. the \lww iale:s, tiia.it may have been encountered(typically needed lo correctly design my n'eatnieml. woife).. And, al^ter the constructionperiod 'w/a.i3. over, thai: poirtiou of tine platnl: dedicated to 'handlling; e::KC«:is.!S. vfcp,EitKs::r would havebecome useless* See Comment 47 iregardiug tins: overall technical hnrpraciticabiiliity oi' tlieROD VLercKS hii' \u\d 48 irejEjardiiiiiE; thus: current sy stern's ahdliit] ito dewateir soil is.,

The need lo acquire pemits for re-routing the Cm±t dimmtiin\i the Canal and impactingwfftfawds is akw cited tu a concern under t.hv ROD,, Pennif ni^mrmMs are IUH animpediment to ciahimnn ARARs, only a pwrequmte. Moreover, all remedial activitiesrequire permits. EPAi and WLPSG have not idmtifwd a '"drop dead cltime"' that iwdiaiuwxfaat sonw pan H/'itfe ROD remedy i;S' mpenntitabk, Thm, permining requirements ainnot IwiM'd tu a wwon \o nyeci I'he ROD remedy..

To cliairily., the 'Draft HOD / rnL<E:[idint:nii: istELlijiiS. lliat lamder \bs ROD ]Et.is:ined.y,, H:s;ii|iii.:Ei.i::ani 'more penririiBng ijs ueii eould ari«c'M. 'The jnenidinent liLirtlner coiri£:],iu(3les itluait the 'j'Ptoposed]l erneti: 1 iis; ]En:efera.l:»hs: 'with, respect, lo 'Compliance iHn.itli ARARs.." Thus;, con:i[jlliajric:e m\hAR&Rs iiajs. not been, "uised. n:5 a reason t<]i rejiec:t: ttie ROD' renusi-cly".. lElaitl er, iit i:» jusnt on<E: <wi:nin<s: crh ria. llia.it latre; ev;3LluLat.e:d dutriiijE; l enriedly Selection, as rssqiuiied urtclet1 Utie NCP, and,just onus: ol: :rinie ciriiteiriuBi IIIL 'ii hJichi iit apf eairs thuait ll:ie 'l]'i'opios(!<JL !Elenriedty is preferable.

THw Proposed Remedy dews ncti styniflcantiy reduce the volunw or umdiy of pollutants.Under the Proposed Amemimem, satumml xtrils ami m-$'m umnturtued soUs will foe left inplace. By WLPSG1 A and EPA rs own admimon, it is not known how kmt\> it wiU uifav \\hvPump and Tmn System so- reduce the volume and nxndty of ml ami miivmnt. cmtmFurther, pwrimnmt reduction in the volume and ttu'icity of the pollutants h imerdyspeculative, ,v>iven £h$ \MraQrdinarify lon$ nnw it ivjfiJ! uifas $& remediate the ml evenmarginally.

Ctnnimnf. 74.

S.R302597

As liw Proposed Amendment tiself Mates, the proposed remedy's goal is to increase tfwm.ob\U,iy of the polfMtants in Ike. an-sile imsanwaled soils. Thus, the proposed remedy actually:ontmdh:ts CERCLA''.? remedial aciion standards. Moreover, thai there appears lo be a stabk'

being transported pwn one place to another- via the ground watersoi fa. This does not xuffice MS proper remediation wider tfw NCP.

A& described in Response 28, iit is a benefit of ithe Proposed Remedy,, .however limited,, that.the removal of arsenic: will be; increased wilhin a confined area by capnirijriji; contaminationthai: irnigiraites from soils to Kins: ground waiter, ttiroogli operation of ttie ]:nunrii:i jajidl i:ii£«it s] is.ite«ri.Neverthelcuis., tl:ie cwi:[ire::rH: boundary of die ground, fc'.ateir1 plunie iis istaihle and is 'E:xpecitE;(J! 1:0remajin. so uLiidE^r this: Proposed l^emedy i>E:e liU:!i]>onsas: 26).. Further, lliis i:ru:reaji< ;l rnol:»il.il^r isnot c:X]:»e{:t :d i.o sig:rii.;[]icant]iy ijrn.]:»a<:it thus: treatment: sy:3ijKin silica: itlus: additional loading iis. verysmall relative to itlwst total jmi ni;!:: entering the system,

Comment 75,.

While EPA claims that the ROD remedy is expected to achieve overall protection of hunuinhealth and ike environment., neither EPA not WLPSG have conducted any ri&\: assessments orother mjiti'site scientific s&wjliffs concerning the efficacy of the proposed -remedial action,Therefore, any conclimotu that tfw Propoiwtf Aintwdment win achieve ovemll projection ofhuman health and the tinwwiwumt are specutaxive at best.

•SSee Response 18. ' •

Comm&nii 7(i.

The proposed remedy n'Mes on an mpnyven system to remediate arsenic and othercontaminants on- and off-she, The complex environment of she she, indiuiing mpredictahlefracmt'ff. zoms- and ground' water ptrthways, and \k$ incrvasnd mobility ofar&mh: under tfwProposed Amendment add lo fhv unairltnnty that the Proposed Amendment will result intimefy attainment ofEPAVx Remedial Objectives for the sits.

See Responses. 2, 6, 12,, and 74.

Comment 77.

Remediation of the soifa and .mUmmfs under the Proposed Amendment is mot expected to beachieved for thousands ofyam. Until thm, contamination and mk to human hvateh and theenvironment wiU persist hi addifum, leaving satumtsd contamimited saiis ifi place or

AR302598

cmsoUdatinii connimiriGMd softs mtkr a penneable soil cover creates the. riskcmnminanon can fatnher spnad should fio®d\n$f fhiaitalion m the ,%wmti water table or theinfhiK of chemicals into xhv environment occur, nits, EPA mimndmumtiy and improperlyvvatmtM the proposed mimfy's achievement of protection of human health and the

"E-einedialion" oi' tftie anil and. sediments, in accordance with die NCF., 'would he complete at.Utie end of construction (at which time potential exposure pathways will have been addressed.)l>ee Response 1),, 'lliis i& <:on:sid.erEih>!ly sooner ithajri in clei1 UCIES ROD ]?£e:irn<siicl>'. S :e 'ke!S]:K)n E:l!iir«igajr(3li]]i|E; flo^Kllug etc.

.As is t'xplametll above, xfw Proposed A[mwdmmt dtw not identify all and violates .mmARAJUs. n$ Proposed Amendment: must be rejected ow this bam afoiw.

See :K.es'ponj3eiS. 6 -62 .

t 79,

WLPSG status rhatt the ROD is not as [(jiiifci'iiv 1 in the long-term lu thv pnypoxetf remedyto-scaitw the impermeable cap required by the ROD remedy would not si$n{fiaintfy reduce themass of arsenic at the $it$ over time, WLPSG neglect XQ disaw thtn mo&t ofthvcontaminated sails would be excavated under the ROD remedy prior to placement above t,keftvmirid water table under an hnpenneabiv aip. n.e Impenneabk cap and placement abovethe ground water table on-sits pnwent sajwftmrds against unacceptable w:p®simx andrdhibiliiy and certainty qfacfaiemnwu mrefy lacking in the Prcpa\ed A[m:endmeni\. Also, onlyd?. minwus amounts of dean backfilled s'oily (in comparison to Mw volume of conumimit&dsoils presmtfy at the $it$)t if any, would become contaminated by contact with gromd water.

See Responses 2, 211, and 47,.

Cammrnt M(,

In Until of ike testing pmati iwedvd w demonstrate the ttffiiatiwntw of the pump and jrnraifsyswn and ike length of linn? needed iro- remediate ihff. soil's vhi the Pump and Trem System, •MW proposed nmetty is noil morn effective in th$ fang-term, than ike ROD mn&dy.

As Utie |3'iainp' ajrul tnstial sj stEirn hasi bee::n 0] E:ratin,g isiacce .iifiilll] siinc : June 1LWIS,, :no :EiJL:rtln;:rt<j!3.iti]rij» i.:3. iK«Mkd.. EPA v illl continiH:; 1:0 0'ArE:r Eie line t'lSiins li.atiiOnL ol' Utie girountl vyaiis r1 ajrid. willi-E!<][iLii:tis: rncKliificatioiiJi as n.«:cesiiajr] it(3' ensure Utie effectiveness of the iininripi arid. i:reai s stEsm,FurthjEir, see Response 1 regarding; "irennsidiiatiion" of the soils,.

iJ IJI i!, i.

ContnuM S.L

Contrary to EPA's arsd WLPSG ', s1 statements, more arsenic will not idtimax&fy leave .the si,t&under the Proposed Remedy than under thv ROD, given that the Proposed Amendment offersatosofaitfffy no discussion of facts and scientific data used to arrive at this awidMsion.

Cow.nwm S'L

This Proposed Amendment does not permanently and signifiawx'ty reduce tfu1 toxici'ty orvolume of comammani's. Lnfaci* the goal of the remedial system under the ProposedAmmdmmt ix to increaw the mtMMfy of arsenic in soils. Funhvr, no remedy reduces themobility of contaminants rntmv than mtus removal of the mis through excavation andplacement under an impernu'aMe cap Mw remedy the ROD presently reqitires. 'liw ProponedAmendment, urdifce the ROD remedy,, does noi prevent mobility caused by floc\din$, a rise i',nthe ground wtuer table or the influx phosphates,

See Responses 7, 15, and 28. Portlier, any isolated and controlled increase in mobiliity wiJIresult: in (he: ultimate decrease in volume since arsenic will be removed via the ground waterpynip i3.ii<jl itne:al s] ;s.tEmri.

Comment $3,.

WL'NG's cmdman thtif the proposed nun-titty h mow effective in the shon-ierm tf$an theROD mn&tty fails to consider the Pwpowd AmmdnwM's- stated need to evaluate the,t[fftictiwms of the Pump ami Tr«as Sysum after ftvti yean and (h&\pw$$itointy of againchanging the1 mnvtty should xi prove ilneffeciw, Such a "wiix ami .see " approach w aremedial aciitm violates the .NCP.

Sei=: lEijEis'Onuso: 4!)..

WLPSG concludes the Pnywixd Amendment Is- effective in the short-term given EPA mdWLPSG's overfy optimistic unfound&d estimates that remediaiion of the yoils via the Phimpand Treat §y,$xm wilt take thiny xo fifty ymrs. AMtmgh the ROD remetfy may take five yearsto implmmt, once the soils are e.\:cavated, the soMs remetfy mU have hwgefy beencomplied.WLPSG \s conchmon tu to xhornem t[ffecfiveness is siwipfy mftwnded.

$®s Responsiesi I., 6, UIKJ. 77,,

ll!R3026l]i:i

Comment .85,

DewaMting -ofitfw saturated stnls upon excavation under the ROD can be achieved with tfwtaw qf'thv currmi Pump and Treat System. As Mr. King explains, examiiion ®f snmUertiretu I'han curmnly com*m\$k\ml and dpemtum oftiw $\imp and Tretu System, averI'weniy-four hours, as is Mtwdard industry practice, would ease any difficulty in ktm:iUn$ afwsaturated soils and d&cretu&'ihe amount ofmutt'wattr generated \n'.r minute.

See Responses 49, 70,, and 71,

Comnunt 86.

WLPSG cannot now claim that tf/ie Rmp ami Treat' ttysxm Us tumble to accontmatiate thewiswwatM' ii'emmitetf during vxcavaiion when iir was fitily twtm before ,ir desigwd tfw systemthai the ROD nvqidred excavation ofmtKhwutvfy conramintued sattimtffd mfa.

See Response 71..

Commmtf $7.

'It is1 indispuuMy WLPSG' s expected COM savings &ha\ drives th& Propo 'd A\mm&wmi. Cos\savings cannot, however, dictate remedial choices when the mwlf is a tcsser cleanup,

As described iin. IJtie Diafi: IUJD AineTKlrnieni:, iin. ac ::'C)ir<3l:Eiiicib 'wnftliL ttie W'CP, eost: i;is. just, <]iirienjine: c:rite:rla liy '"'hicki reirneclies :3ins: i;:v;iJlu;3.ite<3l. The 'PropnoseiJi !KjE;ined.y .Eippssiurs to l>ep::c EeTabk; under all mine .

O.nnment IW.

h' is unlikdy WLPSG will acqiim much feedback _ on than proposal out all, given the <vmmtdescription of the Propoiwd Ammdhmmt pMished for public tunic®. fa\ addinon, at the:public ntiwtinn, EP.4 slated 1'to fuXim usii qf iffe ,nt$ is aha, m Its view, an imponantcansidemtion Hn std&cfin a rwnetty.

See Iftjsis'ponse: 4 iHsijgairdiinijE; puibliic notifkaition. ol tlie ]prc>][K)!s«:d Renicdy. 'FiatuiriE; laim:! ii!i<! !.:s.iiirujishould 'be eonisiidensd iliLirin;; rsiin'EHly sidectiion.

Thv Proposed Atmmimmit propose having in place s-ignificamly contaminated soils . 'Isoils iikdy will nmain in pkia? until a aiiastntphu: event, -OF- the amidtitiw buildup offanning chemicals, occurs renilM$ in massivv mvironinmUi!. conUi

See Response 1!> and 2ft..

Comment HI

EP.A has the power, ami is wqitmvd, to select a remedy with relMnliiy, certainly of remitsand adequate safeguards against these concwm. The Proposed Amendment does not, by ahwgxhat, meet them? sfomdards.

t 91.

The Proposed Remedy is nothing more than a blatant, aumr&pt by WLPSG to save fifteenmillion dollars at the expense of nearby landowners and th& e

WLPSG has demonstrated it1, si willingness ito allocate isignificani: funds for a. remedy lliatprovid.es greaiter protection of human health und, llie enviironriKEinl: or has some other ;add.edbenefit.. However, in this instance,, tet has not been, demonstrated.

RESPONSES TO ATTACHMENT A ("PlncyiecltioiiiiSi oni Aratiulc Mobility alt itheSi.ite"". Fendorf £

Comment .92.

Ln the EP.A FS Report, there are no dtiUi provided on tmmic xpecituion, pfatuw tmwMitwns.,or soil mineralogy ai the sti$. The latter infonnanen is ti cnxical caniponew meded f&jiaiifya miodifk'ation lo the ROD.

Sw. Response 31..

Comment 93,

The residi's of EPA teachate (TCLP) Mslx are highfy tpe w'anve regarding imwprwaiwm ofarsenic mobility, w particular for saturated $®Us,

EPA agnsi'es that tfieire ajru ULnc^ittaijritjies iaL,5iscK:i.i3itei:l 'with using 'TCLP 1:0 (]iLianti.:[y deso.rpl.ion ofarsenic liroim soils. Nevertheless,, this uncertainly exists under boiih iJne ROD iurid ]f*ro]:K)sei:lR.etned.y,, AdditiionEilly,, if TCLF rBsmllts overpredici: des<]»:r]:HJkjn of. ;3Lrs«t:ni:c; 'frmi soils(saturated or noit), soilis. will have less impact to giroiLind 'ater l:han cuirei:it],y 'piredicited. I:E'TCLP results uiuierpredioit clescuptloin, llien more ianisjsjnjk: 'will ultimately be captured in ithepump ;3Liid treat system aituJl ireniove:.:! liorm die ske. !:lee ]?tjs::s;po:n«e 6.

t 94.

llR302:6i[l2

/n: th$ mstiMratffd soUx dissolved conamtmtiom' should be minimized. Within xfw satunuvdsoil, dem'ption may be promoted if conditions shift toward an anaerobic state.

To the extent that desoiptioti increases, under certain ciicuinstances., it: will be captured by die.ground wateir pump a:rid treai: !3.ysl.e:rni and. removed from Utie ske.

C&mmmt 9S,>

n defies fagic to state that a contanumMd maienai cannot, be a source of contamination inthe fotture (what once was the sink for arsenic can cenaitify now be the source!)

C'ontJjin.i netted soils i-epircseni: & minor source to [jirouiiidwater relative to odieir sources at: ttiesite (giro: removed) as described in flLesponuse 9. As |!;round:wal:er becomes deiainer., tJcteiEjradieet. will reverse such that arsenic wil.ll gradually be removed from the siaturaited soOs. litis not anticipated lliis willl signirica:rit:lly l.is::njartliwstn. iJtie li rm;: fi-aine to -nsiisntO'ir'e: die aquilfer (seeResponse (i),,

Comment 96.

i[ftfw 'hot spwi's' are removed ihnw$h mawxtwn, it is loghwJt to vxpvct that thv nmamngsoils will Iw thu source of highlit tirsmic levels and Mm rdeaw i\ inio sotaiom (hat contact?them. The nue of release, however, at present cannot be dvtennimd or even vstiunttfed given'ifw existing data.

See Respoinse fi.

Comment 97.

While the .stautrat&d .ml may bv. $\mimi\y clmned by nanwal downward migration of arsenicwith infiltmiing rain water, ihe phuisitoUiiy of this factor depvnfh on fh& rate tu which arsenicde-sorbs from the soil and itx fnimiauueti! into tfw ground water. Some eMimaUts &?\ thispoint have aimady been pm forth. Making the tmiwnption thtn infiillratihg wawr am obuunimiant equiilbnimi wiih the soU Jt&fuh, awd tfa$n imn$ Kti' vwlMsftw aentied materials(mritiMff between / and KM) L Kg. Jj, a projuaed period of 3>S,QW yam nuiy be. nwdvd doremove ml anwnic Mow ktizani'oux lirwrto.

][;or ][MJL:r]pK3i!S ::s of e::sitijrnJ3Ltijri||; ithe mrcNJindwater re^sinraiuoii pe::ri{)<l, MJ-^XHi assumed a K.d vaJtm;;equal, to 2.9 Ulkg; (EPA, Soil Sciraaikig GuiidaBce, Technical Backj^toimd. D(3ainrMMril., 19%).•See Lespon E: 6 renai'di tig estimates oi thie n=::!:oi:;ii:ion period.

Commmt :M..

Making pmdkntms based on the physical and chemical coitwnunK' of the xy&im tu it

40

IIR3D;i!60::l

pt'ewntiy wtists ignores $w fact that changes are inevitable, only she magmtmie and timingtifff unknown. Funhernwre, large $a:ik\ptwuiriKiiwns m ihe system may remif. from flood orother mmml taverns and thus overri.de the predicted trends.

Tin;: need ito rely on predictions regardnijs; tins: physical and chemical constraints exists under'both the 1R.O1D and 1'toposed. Remedies (s;ee Response 2 regarding ceirtaiinty arid. reliability ofithe remedy), The possibility of large-scale 'perliirhatious' also exists under both remedies(see E.esponse !,!> regarding flooding or oilier natural events)-

Comment 99.

While arsenic may be rg-intniduced to dean soils used to backfill ihe excavated mtitmal, ifthe pump'-and-ireat system Is functioning properly there shtwid be tmfy minima!.nwonhitmnation., Additionally t the total' quantity of arsenic at the site wii.1 tffrviousfy b&diminished through excavation r leading to a dimmhhed qmmtity that must be remediated ansite.

See Response 2'\. Fuidieir, s :e Response 1 ircgardiing the JSfCP d.elinitionL of remediate.

Without more, accunue desorption data and further information on ihe actual phases involved,w cannot make absolm\?. prediaiom of the, fate of .arsenic within the pmmrty saturnied .urits.Further data, such ay description nties obtained wing intact cores thai are manipulated asdo&efry as ptwrMv lo vxpgcivd stiff conditions, are needed w make a scMntiiflcaUy soundass&ssnwnt of the siut'sfaU!. Addlnmally, pmc&ws (or factors) i&attin$ to fh& naiumlcontainment of the $romd waur plume am presently unknown; whether Ms candition willp&msi- in the fattwe is thus mc&rhun as are cmdiiions that may lead no a degradwhw ofMs conlamme?\t phenomena^

See: ]:!.i;:5i[)<:»n:5C 31 reftarding; the: neei:L Cor additional ]lab'4:»r,ELtor stun:li :s. Issun£:s ire jaird.inignatural containment of the; ground 'water exiisit uindeir \x*\h :reirn.«ticli.(EJ,s; ajrid. are mol: appllicablle loremedy selection.

TJw deswption rate mil pw^wvdy decrease (a$trin tu'wiung a siabk' sening) ax the morelabUe fractions are removed. Thus progressive cleaning will beccnne very difficult.

By thiis loja;ic, the potential for soils 1:0 act as a 'isouice" to groundwater will only decireasie<v:itJ:i time:.

t ItlL

Rather than slwwfy removing tmwuc by natural dvsorption processes coupled with xfw

AR30260I*

pump-and--Xrea\ ground water system, if is likely that deyorption will he minimal the majorityof the tinw, letidiwfi to link'. Miti diwmise: in amnic soil .toveto. "When tmenic is mitmed ifwill be in sporadic, intense puLws that may uxctwd t\w capacity of ihv pwnp-and--tmu &y$umand thus exceed thv containment zone. Moreover, liw natural proce&ws currency leading loa ".stfflW'sr '' ground water pHunw are, unknown. Xf conditions chmgff wiU tfw plumv mrmnncontained?

WLKG agrees tliat desorption is likely to b>e fairly minimal inoisit of the time.. Further, acount) inationi of manual processes aimcl line ptunp> niui treal: sj sitem cam likely J3LC:coirnjrnodate suic"pulses11. .SS«is: l espon : 2(> regarding the stability ol: itlinst pluioe.

Ctwim&nt JiSiL

Dworpition rah's may bt &x.c$$din$ly slow and mpdre tfatmai'sds ofymnt to fyrin§ the mlarsenic lively Mow kazardam kvds (< 2.1 mgt'Kft).

.According, to EPA, "liia^urdkjusi" snoiils are those tiiat iKjsi^Ked 5 ni,g/'l TCLP arsenic; irnost O'i'which, will he: rcrncivecl firccnn the: isiite u.:ridnKr <siidieir aliteiniBitiLve , Further, EPA. did irioit id.)£;n,l:i1tJrie re(].iLu;ti<:m ol soiils to below 21 nig/kg &% & irenn=:di;iail objective,. See ]ft.e:spo:rise ]14.

mnment. jfiftl',,

$hon«penods of rapid d$wtp\im may WW spmulictUty due to /•(E i l /'j'fuctu KiOJ !: J?.M thewater table and fpossMy only once, or less, a century) o:iiY nropMc evmts (&.$., floods,tornadoes, $nm anthropogenic inimtiucticm). WhiLv such trwrnts wmld likdy account foronfy a small fraction qfnnaf, arsenic removal, when tluy occur xh$ pump--and-tretu systemmay fail or be exceeded and tfuts ntfffase: imwnic outside the capture zone.

!:k:e ]fGjs::s;po:nse 2 regarding c:erti3iniy iind reliialbiJlity o>f Uie ns;tniiKd.>r md ]\\jti$\Kmw 2,6 and liOliregarding; lUMLinr;!,]! coicitjiJiiwrrieitH: ol' llie: jjii^MJiT

Ctwnm&mt

ArsMuc present in the xaUinned soU, while not a source of ground wawr contamination in Mpast, amid he a $owm of arsenic cmtamJimfmn in thvfiitm (as noted above:).

This directly <:oii:[licts; widi (i^oniniLenLt 1LOO. .See Response.

Comment WS.<

Simply selvaing material with a km flff'inityfor arsenic mU mmmift? n ctnutwiint wn of thebackfill material; the solidy should have How aluminum twd iron contwU, bv rich in sitica oreven cadwicsxe mauriah, and be ofantrse gmde (low mr fact* area). A course nmtfff

.AR302605

siliceous sami or caicitefdofamte hrw in iron and aluminum, would be ideal.

See Response 21 and, 64,,

RESPONBISS TO- ATTACHMENT B -(''"Re-piew of the Aiicieiadiicieinl: lo ttie Record ofibr tlie Whi;il:miiiyer Suipeif nind iBiite".. R. KJMJE;,, Aiuguwl \[W,.)

Comment $(%,.

The ground water model may he Incapable of predicting the ef/ecfiveness of the remedialsystem proposed by the Draft ROD Amendment.

'Tins: jE;roiLind ral:er model was inteTuied for purposes of desi^niniiE; the; .groundvyater ptunp andtreat system only, which has; mm been c:o;nsiiucted, ITie >:[feaivene5i,5iri ol: itlusi ciomtaininenLtand hoi-spot pumping; !S>'stenri, :Ecir purposes oif nsunnssdiiEitiiijs; soils, will be confirmed hy actUEil:rnLonitori.:rij2; m opposed to further incdel.inLiEj. Thus., the .BrounidwalxsT nKxIell itias no reiie 'amc :t(]> tins: :DraiEi: ]R.O]D / jrins:ri(irn;':Mil:. (NevKrthKleus, am e:xce:ll ::rii: correlation, between the: caLfjiiurezoirie i:TeJ:i;:l.e:l by tlie rimcxilel and that actually observed at trie: site has been seen.)

CmwmmH' JW.

Therefore. th& geological ini rpretaiion of the site condtihms cannot be relied upon.

See Response 10(i.

Comment .HW.

Given shew deficiencies' the fmctunt mice mrv&y data must be viewed as inctwrtplete.Consequvntty t. dedsiom and interpr&UiHons based on ithe fracture trace Mtrv&y are suspect a/the very kwst.

Whihout an understanding of the structural camroUx infhiendng xfw heal area $e$i®gy theptntMiknnefric pm'.wre data available from the &ti$ ami wfaa? witw foodiM and other wellycannot he mhwpretvd wish any degree of canfMence.

See: EjKsponusie 106., Further, tJtie uncerl^initii^s uuLrronndiiiiE; tlines iniiterp'insitatioiri -of ]f)(]€enLiti,cnnetjri,c:data exist niruiier boitli die ROD1 jjnd ]?»rni;K]'!i«a;l Reniedksi. Finally, the: redundancy in themonitoring system (i.e. nunibKr of wKlllsi isampled, lie:i:|uns:nc:y of siainplin.!!,, i^nicilirniiiaLtot^^testing of trenttnent pliant iiufluent and erduent:., l:ns:iC|iJL'Ki]nt :rnonil:orii[i(; of suiface ^ ai.i;:r etc.)

|!|R3I]26I]6

provides a high level of certainty titiat: ground/water iis; successfully being remedial.!; ! and thaitdiisdiarge limitations are bein ; met..,

Cammmt IM

Btwd on the above ttnutations and deficiencies the geological data on which all subseqiwMinwpr&uuiom and remedial dnsi$n dt'tiswm nmt be. viewed as imcatrate or flawed at bestConxequentty, the mbs&qu&n anafysis of site conditions amnot be rdied upon for sdeaion ofremedial alwrnatives.

See fijesponsie 106 and, 1{)9.

C&mmmt n.l'.

The ground wa er level records kepi by Chester Engineering during thefiw yew ofsryMmoperation indicates thtU along the norxkmi boundary of the a:\wnm zon& the kydraulicgradwnt within .the 'I ppm contour- Unv (mi Cfo&Mr Engineers Figun? 2J 6/26/97 and Figure3 Ll/24/98 Evaluation of Stonr up and F&rxX Quarterly 'Ationiumng Data Ration) is ammtendyfrom thtr sos&th of Tidpdiocken Cm± around wdl MW322A mwihvaMvvanis umanh wdi CE4.Btmntst ground wiUtr flows from area? of lusher pmswff towards areas c/ Imwr pnwmre(L$. down gradient) the data indicates that the exiracnon xy&ttwi has notf captured i$w groundwater along the nonhvrn iw.nmd:iry of Tuipehocken Cnwfc (stw aMachrnent),

A.ccordiiijj; to Clieisttsr Irlngineeirs (September 21, ]L9!)9), Utie n<3'iw tliinE:c:tio:ris sltiown <on die;referenced! i:Lra hri]tif[. (Sepl 9\\) and sm1:i E:c]uemt drav^in^s are generated by the data interpolatedfroi:n se\r<E:rEil WE:! Is throu^houi Utie compliance monitorimg m:i:"/ork (litelfeir to draft A:riimui]llELep'ort). I"tie: compliance network t:o:nsi.stSi ofoveir 1)0 monitoring welh, v/:tiic:!h |>ir'oviide: a moireaccurate (jlefinii:i(]i!n oi ihe overall How gradients tht'ou.jE;l]ic»n.t this: endre si :, ;3.;= WE: 11 M localized.areas, 'Hie nesu.lt.Jiii]E; rcaind'ii atisir contours; ire 'eal dia.t CR-4 i.;= Located im a ciro -gr Ldiienitusilaitioniihip 'with MW-322A, irioit dijrei:;itl.y dowr radieot., As :ru]>ted on ttie drawings, tie flo'wat. ]vrW'-3-!2A. iis; pri]rn.j3.:ril;yr t(]i ttie «<3'ittl3t:i, due: to the i;;ontii]inj:rHMri(, ]:irovid,(s:d l>y the extractionwell network,,

Further, tlie extraction system u:s.es; the 1-ppni s halllow XOIM:: njrsenic c;oni;;entrEHi'C)n to definedie teirjseit coirit Lii niLenLt xoicie.. II: i3L.n>F grouLndiAWiUter \ltwv is :noit i;:oifil tinL<s:{l Co th«s: :ri(]i:rth oi1 tJriesiite:, iiiOrt]]i ol: I'ii]|;[je:]tiCNc:kis:ti, Citcek., it: is subsequently ca|]itu:ns:i:l hy thus: ]E«srijcnuiter well syai&enncli.!t«i::tliy to tlms: east:. In adj^ijtion, tliie ;aLHJjJlyi:icaJl results; of sjimpleis. Ifi-nrti inoiriitorijrin; 'wells;PO-1, and M"W-3]16A. have bcai near or bslow detection levels during tins: ][,ast: yair. Finality,!:PA, v/iUti assistELiiLCi'e licnn tliws: USGS,, will coiitiniiLie to overs.ee the ground 'waiter •rcunedi.Eit.iionefforts artel reqinitns: ]rn.-:»3li1:ic Lti1ons1 »,s nns:oesKary tio iSiiniuins: s,u£;ce::s1s,,

Comtnem L\2,

44

AR30260

Chester Enginwm' report "Evaluation of Sum up and First Qmn&dy Monitoring Data Report11/24/98 Figures 2.1 and 6/26/97 Figure 3" show ground water flow dir&ctwn arrows in thetimi to the nonh of Tulpehocken Creek thai indicate ground water flow dmcthws tawanh theextraction systwn in the area around wdi MW322A. This is patently not the case.

•See Response 1 1 1 .

miE J.O..

The arrow shawing ground water flow soitthweytwanii is lomted much too far to thenortheast and is misitwding do say the least.

Sec Response 1 1 1 .

Cvinmmt .L14.

Based on Ms factual data, ii is dear that the ground watvr captim systwn after otw year ofoperation has fatted to control gnntwd water in the niquired area, '.liw syxfam Us Mwntfiweimffi*a'm: for remediation of the. ground water and Mw saiLv beneath and within the. J pprnisoconaintmtion contour. As snick j:.f cannot be accepted tu a preferable aUmwive to the.ROD remedial aalon.

See fl:esponi:3e 111. ]F:iJLiptliLiE:r, the: issues rais :i:l [is:,|;ajr(ilinL;Ej thus: captiure zone would exist underithe ROD Remedy as well.

Comment LI'S,,

h is of note that Geotrans used pnwipitwwn tnflitnithwi rate? varying beftyveen 5.3 and IL8inches of rainfaU per year m their groumi water motlvl. TMy InfiUrafion rate averaged overtfw year .is equivalent. ifo> approx.imaf.efy 4S gallons per mmute of flow through the aquifersystem in the &it$ area and has jmied to remove the aintammanM over a pmod of at kwt23 y&ar.y. No infbnntuion htis been presumed Mat mdlaues that pimping the ground water atsimilar or high&f rates (double or qmdntple) from an area that is slightly larger than thearea of Impacted , mis will enhance this apparently ineffective removal rate., Absent theremoval of the source term (the mutmted and maturated heavily and modemtetycontanwuited soils) pumping gnwwd water by itseif will do linle to effect remediation ofxhv

Sens: filetfponsie 9 [ Eiijjirdijriii; l 'h<s:tJ:ier soils are acting or will act a.s a sour;:e to ground water.See ^Response 1 r'ls aj'dijriij: the definition of "remediate". Under boitli. remedies.,, siigTiJLilcant' oliurrnsis of soils will! remain on-site, ho e ir, u;rui:er die If rni osecl :R:eine<Jly,, t«» the; extent th;3.t;3[rs.is:Tii.«:; become:; mobile,, it: will be capcmed 'by ttie pump' artel lieiant systis:;rn; iurid. ]>ennEinhs;n.i:l>pircirnove:! iTOin the site.

/IR30260I:)

(Comment Lift.

Calculation oftfw hydtuidic gradients in the turn to it/he north of Tulpehocken Creek sine® th&extraction $yMm wtu installed indicate? that vinmlfy no change hay occurred in thehydraulic gradient's- or they are tmtry from the, main site area, Cmmjuenxly, the. $wmtiwater extraction system wrM not Improve, or remediate this ami.

See Response 11 ]L regarding the capture zone. Fintheir, rnLonilorini; of tine capture zone willcontinue for tJtie life of ttie: groinidwaitei: pump* iurid. treat. system. In. the event: dial; changes areseen in the conlif'unition of ithe capture zone, niodiilicatioTis would he niade to tlie: system.,such as' altering pumping rates; or, if necessary,. installing new wells.

Comment I if 7.

Extraction of appnmmtitefy ,100 $pm. of ground waiter from tfw bedrock h:ts mit&ted m thedvwatennfl of significant' sections cfprvvioiisfy mutnned $oil\ even in tfw vtidmy ofthv southside of thv Tulpehocken CnwL TMs pumping rate1 from, a #nmnd waiter control xy&tm notdtisign&ti spedficalty $o lower MH? water xtMv m the arm of contaminated soils has residl'ffd in90 percent of the highly comamimmd soil toeing dewitwtxL Drawdown ofthv ground watertable In &x.c.tw of 30fawt has been measured in some1 amis HW 6CAf)fiWX v.n ditmettw withadjacent pwnpLng well n:\ies of 2,6 to 7.0 Rpm (PW06). This prows thtU it is possible t$dewaxer lar$e areas oftl'ie slt& to Mow the base of the mr idat. soif,x with accepfable andtreatable quantities of ground muw.

In ttie areas; \v\wr\* <s:xc;3.vatioti /ouLl(3l occur under the ROD1 lEt-isrniLisi'd)', (iiria /do'ii n. lists; aveta^ed4-6 fs:ei: (Chesi r, 1999). No excavation of sioiiis is planned, hi and around lrWK \\n:\w eirtlnerRemedy. i-'iiirUrier, see IKespouse 411 regardiniiE; tine liniltatioiis of drawing [;iroiLindv atis::r dowtifurther.

Comment Lift.

Mmmtiw the wacavinion ami twd cm\pHt'.fff sequential excavation,

See 'Responds: 47' .

Commmt IJ.!'.

Complete mmwtitwt -wish the cnwk or sections of liw creek tfemtmti. By cmnructinii cofferdams of ather end of Tutp$lm±en Cmk onti' piping the stream Jkm water around the areaiwm$ excavated hydmtdic gradfant's cioM w the cnwfc wotdd he decmnsed and seepage fromthe area of the mwk would be reduced significantly.

!SIIE>K Reis:K)n e 47.

46

A R 30 260 9

Comment 120.

Install temporary cutoff watts

See ]ft.espon;5,e 47'.

Cointnmt H2L.

The Draft Amendment to t,\u' ROD indicates that "first and foremost." 30 mUUtwt gallons ofwater will be generated during examttion of contaminated .mki. This volume of water ismeti' ay a prim® mmon for rejecting the ROD Remedy, This potential quantity of groundwater shtwl'd have formed part of the design basis far the. treatment plant became the WLPSGwas required to excavate the saturated contaminated soils.

See Response 47. Iitie generation of water i:s just one of many factors contributing to dietechnical impracticability of excavating saturated soils;.

Comment' 122,

This 'is well within the design buffer thai should have b$\m allowed during design (viits ormhws S0%), FhtrthermMrt9,, as discussed above.f even if Ms is the quantity of ground water t&be dealt with \hern are ways of mginvering around the problem.,

isee Response 47,

mf 123..

rriiMti.in ,\\stv\,t w'lnmiijLMNr^ij i ULtl.il Uitiuit lirii., 'i, kikiiJiriiiJi.il. I..JMI i'm.nt.*t \.tj JL-J i i' .un \>'i r

r)lit(; .O'/' u ri /tr n w/wfinfl "'5(3' HiwTi!r<?;i g.:rJ7(3/t 'vwir.pr"' must foe rejected.

!k:e l e;:sp(]>:rise!S 47 anid 70.

Ctmwuni I'M,

The available information Indicaws than after one year the. ground water nwaaion system hasnot controlled or v:xt.n\ct.ed water from tfw area to the north of Tidpwhodwn Creek and assuch z:s not causing r$nwdmiwn of the ground 'water or soil The xuuenwnt made by EPA onpage 13 of the Draft Amendment to the ROD Us, £her$fi:we, incorrect when it states that tin?Altwnanve Remedy will enhance and hatten the. overall removal of anmic from xhv soil.EPA hay nat way of measuring the effectiveness of the system. Any d&asion based on this

AB3CI2:SI

lack of data is therefore, arbitrary..

See; IResponise 1. 1 ][ ,

ti .125.

Renwtmfl the Creek can be medx® reduce and remove Mw poUMiai. far seepage from thecreek zo soil er.cavattu.ms.. As such to canfonn a major benefit lo the R&netUal action af rhesite.

lit i;s unclear b:rw the cleanup' action, nnighJ: benefit: sijrice: seepage willl come from lineunderlying aquifer. See: ]K.es;ponse 47 re[;aidh;i[; the technical impracticability ol: implementingthe ROD Remedy,

Canal Hocks are rtmtindy dosed off' and dwmttfreti for moninnction/rmovrMwn work. n$d&fficutoie? diiscnlwd in $¥w Draft Amtmdm&nt do not preswu a sitffidvnt' cauM to reject aremedy thtti demon^mbfy and permanemfy removes \he nuijor portion of the coni\:iiniium$sfrom the she.

In the instance o:f iJie R€H3 ]HjBined1y11 ithe 13mm Canal/][j>c;lc: rould be se\r'erel.y inripuaLded andprobably lo&t lit: i:s; just: oms: of many advjmiages uirulis:!1 die EOT) '[Kennedy ijtuii:, mot: onlywouUl Utie: Can;:J/Lo;:l; irernaJin intact,, but 'wonkl (K accessible 1:0 tJtie puh tii: . A is a result., th.<s:.P'enjrii lvania Hisloric a:n(JI Mtuiiemin iC(]icni«iiL!s;:s.:io]ri (FHMC) has ii:KliLcal:iS:(l titieiir snpp<[)rt, i?or tlins:l:>i'0]:K)se:d Re::rni<;:cly. Further, ij:ni;Kicts; tx» tlms: 'Uniou/CanaJl ha\'t: not t s:en ULisusid to "inject areiiriedy", ra.tlus:!' they are one of many comsiiderationLS. im remedy selection.

L&mmem &<&/*

The Draft Amendment to the ROD purports that "more arsenic widti ultimately leave the:site" under the Alternate' remedy. This does not siwvn, ptwMe ami has not been quantified.The ROD Remedy provides for dmmstmble removal of the arsmc contaminated mih andthe rmovai! of ground water contaminated with anwnic.. The lime frame for site, remaiiationl.s controlled by ground water deaiwp. Leaving more contaminated soil in place cannotreduce .rfo.gr time frame for cleanup, ComequwUly, the Alf$rnat& Remedy cannot be ftuler andcannon provide for greater lon$«tmn eff$awnv.s$.

lit: i;:s; unclear hww line "]fS.O][]> ULeinedy provides ibr deniouitraLhlle tisimLO 'iELl (]>:[' line arsieniccoi:itajrn.inLi3Lted swills11 vv\m\ under iJtie ROD IfGmiiLecly, soib ajre rneirel]/ unmri\ frcjorn. one sitelocation to ;aLin:HJtier, See: Response 11 reg;aLrdijrig ttie (iieriiiiiJion of '"rssined.iatt:" .aimtl :RLes|>:»]]us : 6regarding die ground -wjiiter :ns::sit(3ia.]tio:n period.

dwwmU $28.

V offsite treaxmerM -of sorts is more easily implemented than omite \*retwn\m\* then if should beproposed for either remedy .

Tltii-js. change ijri tl:te ROD 'was made previously and is noi: affected by die Ajmendment,Further, off- site thermal de^Hptkm 'was not available at the time die ]R£HD wa.;s. signed,.

(Comment 12.!'.

If both mn&die's are poi\m$iaUy not capabk1 of ckamng up the1 grotmd wafer to fh& cleanupgoals and the Atimiate Remetfy rdies mainly on ground wiiet1 cleanup ,to remediate the site.then it awmot be viewed as betur remedy. Jlw. question of time frame for remecfhuion isdimtssed at some length in the \>amm reports. None of the besting or Mudiffx completed todate have shown themselves capabie of predicting the cleanup lime. This hay hem pointedoia by EPA. As the site k:i$ .shown i d/ capable of remaining contaminated since the .1950s/! i'.s1 afosoHuttefy improbable tha$ tfw site wiU become deconiammaied by leaving conuimimilvdsoils in place ami relying on infiltration of precipifanon (which lias Iwen mg&wgfor1 a Honglime) to remediate th& side. 'The concept of using oxidizing method's to enhance rvmvdianontoas noi bffen tested and is viewed iy EPA ito b$ spvcidtniv®.

!s;<s:e Response 6 regarding tl:ie tilmws! frame \o leisitoire U ie aquiieir. See R.esipon:se 50 rei|;3i:n:li]{hz use of oxiidiz:ing i:netli.<:»(i!;si 1:0 enhance remediation.

49