-----middotmiddot t-Tmiddot ~

bull ~~bulli- STATE OF MAl NE

r Department of Environmental Protection ~~- bull _ bull -~~ MAIN orne( 114yen IUIUliHG HOIIIU~ SlAUT AUOtJSU middot middotmiddotbull -bull-n s~middot-bullbull_t oow

lCif-)fiiiNII

JOtiM II Me~liiHAN JIIl April 10 19119

Hr And rev Tovt Centnl Haine Power Co Edhon Drivtt AUampUi tl Maine 0bull336

liE 1 Dnft ltuwdh l l nvntiampation I Penibillty Study P OConnrtr Site rrepand by I C Jordan Co fuc Centrd Maine Power Co and da ted NoveMber 1988 and lolvent atnction Trutability Study Report dated Fe bruuy 1989

Dear Hr Towt

The Depattbullnt hu COaf l eted its review of the above-nfer-enced d01uMnU and ha a the fo llowing c~nt 11

) ledial lnvntiution

~~E~~~__~r_r 1) Pbullabull IS-3 lut paraRnph 11t1te t hat PCI bulliarattnn hu occurred

beJond t he lecurity h nce into IHampampbull lpoundook ndibullnts

Section z o i----eampe--2-3 lint puaanph indicbullte thbullt Ri881 lroak dou provide ffl r

rec rutiond 111e1 (fhhinK in lll rtiltur) dovn1treabull o f the OConnor Ute Do no t reduc e the aignifiampbullnce o f t he Brook

Sec tion JO i l Pae- i-5 Hut rbullnrbullph provide bull dhc u n ion of bullny dhcrepbullnciel

whic h uhted between Jordbullnl bullndyus and EPA bull 1plit1

Section ol 0 r-p-s--11-6 - 6 - lZ The overhurden unit1 1hovn nn PJgu re11 6-2 bullnd 6-J

do not Ntc h t he untfl dl lc ribed Jn the narntJv- (JI 11 -10 - 11 - 2) Where bull the clbullyey s Ht described Jn the teat Wh111t s the ampolosic bullnd hydro l ogic d1nificbullnc e of the s bullndy till s hown at HW-02 103 bullnd lO oll but nlJt Mntioned bullnyvhue in the teat

REGIONAL OFfiCES OfttllltCIbull bullffbull

I I

I I

2) Pages bull-10 -bull-12 Anu111ing the narrative deacdptinn of ovrburden depolitl 11 correct Jordan atill doea not deMOnatrau a thorough underatanding of the geologic and hydrologic nature of the overburden deposita apecifirally the Presumpscot Formation A very ROOd reference edited by Andrewa and othera concerning the geologic and engineerina characte rhtica of the Presurnpacot Formation il included in the Rl Biblioaraphy and cited on page bull - 11 But it doean t appear that thil information wu utilized in the interpretation of the condiliona at the OConnor Site The first aentence of the second paper in that reference ( The Presumpsco t ForMation in Southwu t e rn Hline by Woodrow B Thompson) de sc ribes the PreauMpacot Formation as a blanket of glaciomarinl silt clay and und Jordan assigned only the clays overlying the till to the PruUIIIpacot ronution and ducrlbu the s tratified clayey allta u relating to t he poat- glacbl phase of cou t d uplift This actually Nku theM part of the Preswnpacot Forution In addition Jordan deecrlhet the clayey eilu as being wdl-jolnted but make e no cOIIIIIfnt conce rnin~J the per11eabllity nf theee fracture bull and their effect on ContaMinant Migration A dhcunion of thh MUll be provided The paper by Holland and To lMn Te chniquebull of Groundwater Inveetipation ud Modeling in Harlne Chy 1 A Cue Study in the volWH edited by Andrewbull et al des c ribebull the geologic and hydrologic chuacterhtics of a tita with a aibulliln atratigraphy

l) Pal bull - 2bull reference the Appendh where the HSL Organicbull re11ult1 can H found Indicate vhich if any u11pling pointa are conaidued backaround for organicbull

bullgt Page 4-32 top of paaa third untence should bullgkg read uakg

5) Paae 4-35 top of page 11econd untencelltOdify reference to fault aone bull ban th Riaabull Brook

Section 5 0 1gt Gana(lt The 8fOlogic and hydroloaic data cn llec ted to date and their

eubuquent interpretation aa well u addltionll inYettiaatJons propoud in the IU15 are not aufficient to adequately characterhe the lite 1 hydroget1logic regilllf and the rate and extent of conta11inant Migration or to duign an effective groundwater pup nd treat syltM Hany of the iuuu railed in earlier reYiewa have not been addreued There are s till significant data gapa and eeveral of t he basic interpretationbull concerninamp dte geoloiJ and hydrolORJ are queationable

2 ) hgea 5- 7 - 5- 11 Exphin t he conta111ination found in monitoring well s HW- 101A and HW- 101 given their upgradiant loeation 11 ehown on Figu re 5middot 2

3) Pagea 5-7 - 5- 11 The deacription of groundwater flow cond itione in t he oYerburden MUll dhcuu the iMport ance of the well - developtod fracturea in t hto clayey tilt to infiltration of aurface water and cont am inantbull Since t hen h the pouiblity of PCBbull attac hed to to ll particlea mlsrating along duinage patht located in thto fra rtured c laye y eilt thtl potential for infiltration of contamina tion along t he fracturea MUll be evaluated

41 Paae 5-20 hat pansnph it is ponible that the PCB contalftinatlon in HW-1015A vu due to udi~~~ent lnflltntion durin11 well inttalhtion but this cannot be conclullively 11tated at this time The poulbllty that HW-1015A maybe contaminated mutt be considered when delignlng a groundwater tratment tysteM

5) Page 5-21 second )lllraRraph what signifigance tloes thh laboratory contudnation ha ve t o the overall QAQC for th e lab

Section 70 i~-4 fi ut paragraph change t he reference to buve r daM u thlll

da111 h ac tually ~~~an-made

21 Tabl e 7-1 indicate the unit s (ppbpplll) n pruented hue

Section 11 0 iJ--cr-1 Overall the presentation of thh Mlterial it poor There

are nueroua graiiiJIIItical at well u factual erron thoroughout this section uat be reviewed anti rewritten by IOIMIOOe ex perience d in bioloaical aStellllllnt t

21 Paae 11-7 third paragraph fifth untence botto 5 what

ll Paabull 11 - 9 ucond paraaraph indicate that the fiah obnrved in Ug111 lrook calM fr~ only a bullbull11 portion of the brook Larau older fiah alhdampedly exist farther downatreabull

4) Paabull 8-17 lut paragraph delete the word bull rtebull in nference to the backaround ttation bullbull it blpllebull a areater diatance than actually edata

5) Paae 1-19 top of paae firat tentence bullkebull no unu

6) Paabull 11-19 fint full pan1raph include hen that in addition to dUentinina if there vaa (is) a public h lth threat one or the objecthet vat to deterine if then wu an environMntal threat

7) Paabullbull 11 - 19 to 11 - 21 overlaJplnl untence bullke no unu txpldn how bullhed Jnduttry (which in particular) and farina could lead to low hveh of PCBs in back1round bullbullbullpies

II Paae 8 - 25 top o r paae end or sentence should thh read and other carnivores bull 7

9) Page 8 - ll last para1raph t he on-site h1oon t ve re no t con11 tructed dudna interiM re~~t~dhl act ionsbull and conlidered vetlands

101 Pa1bullbull 11 -33 - l-14 Specify which section or Rigas hook wetland h bdnamp evalua ted here The func tiond attributes dnwnatrea111 or the OConnor Site are probably quite dHrerent t han t hou adjacent to the Site

Section 90 iJP~-10 tecond tel of bullets add bullampration of toil particles

throuah joints in upper tilty ca ly u a potential bulllaration pathway

2) hse 9-27 ncnnd comple te bullet include Rina Brook ae diiiMnta 11 a receptor of site-derived PCB a

Section 10 i--middot--p~-i-22 first full paragraph 14- dichlornbenzene did excPed the

State o f Hline drinking water 1tandards on a number of occui ons

2) Pases 1-24 - 1-215 over lapping sentence this statement c annot be Made bued nn t he limited biota studies conducted at the OConnor Site

Section 2 0 ~jei-u first full p111ragraph in~ cues Hline hu adopted HCIa

11 ita drinking water standa rdbull but hu set 1tandarda lower t han HCLa in other cuu In additinn 1 4-dich1orobenune dou exceed Haine standards on a nuMber of occaaiona shy

Section l O i)-pbullleJ-115 1ut puagraph ~Iaine drinkina water atandard for

1 4-dich1orobenzene 11 27 ua1

Section 00 r-pa-e-152 lut u nt ence provide a rationale for ng_ perfor-ina

bulltala analysis in the 1t0nitortna progr for thh Alternative

Section 7 0 l)Palbull 7-Z rractun11 in hedror k provide dhtinct preferential pathways

or network s dona which contawlinatlnn NJ bulliarate wherea s bulliaration

~r=~~ ~c~ r~~~dmiddot~ank~rlt =~i~ertt~r the loc ation danaitJ orien t ation pen~eabUity and inte rconnec tion of fractures a t the site to justify the a nU~~ption that Milration patterns in the bedrock re ullble t hou in an unconso l1dated Media In addition to ina ta llin8 1t0n anitorinamp velh Jordan -uat consider the uu of borehole aeophyaica and other bullthod e to evalua te t he bedrock fracture 1y11tM and its affect on site hJdroloiJ contaMinant bull i aration and reMediation It h pouible t ha t thia work can occur durinamp the RIIMdial Oeaian phase

2) Paaea 7-l - 7-4 it IIUSt be deterMined how PCB a are Mia rating to and via ar-oundwater - aa an i11111hcible oil phue and or- attached to udtent particlu

]) P111ge 7-20 Injection velh are not allowed fnt dhch111q~Jog hnatdoua vute in Haine (lll H l S A Chaplet 54l - lulaa to control the aubaurhce dhchuaea of pollutbullntl by well injection) The dhchuaed wa ter would have to Met all 1tate drinkina water- atandarda bdote injection would be allowed

41 P11e1 7-21 - 7-29 ln loc1ting the rumiddotopond sroundw1ter u tr1ction wdl Jordan h1 11 over-llia~pllfied and senerelhed the libulllted geolo1ic and hydrolotplc d1t1 th1t hu been g1thered 10 fer For in1t1nce Flsure 7-2 1hould revel th1t the prennce and thicknu~t of the haul till h known frDIII welh 1t HW-101 1nd 103 well HW- 1068 1ntl test pit TP-116 not th1t the till forms 1 continuous hyer over lyinamp the bedrod--Connect inR the dot s between the known datbull polnt ~t h not ev idence thbullt t he intupret1tlon bullctu1lly ui1t1 in the field Another ex111111le h the statement on rbull1e 7-21 that genenl grflundwater flow at the dte h frOM northwe1t to southwest Section 5 of the RI spbullclficl lly 1t1tU th1t groundwater flows from north tn 1out h in the ovuburden bullnd 1110re e terly in the bedrock In addition while the proposed extraction well EW-1 1111y be 1uccenful in intercepting 1nd re110ving contabullinbullted aroundwbullter the nhting lklnitorinamp well nbulltwork with the addition of HW-107A bullnd B h not 1dequate to dbullterbullinbull its prognn Nw p1in or clubulltbulln of wells u1t be atrateaicbulllly located both inlidbull and outlide the utMited boundbullrin of the plUM 1nd c1pture aonu to deterMine if the aroundwbullter eatnction IJi t ebull h auccenful In partic uhr 110nitorins welh JMJit be in1t1lled in bullre northu1t Ult 1nd aoutheut of the ntraction u Thh h puticuhrly i11port1nt since Fiaure bull-bull in the ll 1howa bedrock outcropbull in TWA HI where the hiahut concentntion of PCBI (200000 ppM) in 1urhce soil bull occ ur but only 110nitorina welh 105A and 1051 ere clou to beln1 down andlent of then hot spots Thue are no aroundw1ter d1t1 northerlJ and eute rly of TWA III

Section 1 0 i---a-i-4 fir 1 t full plrllrl(lh biota MUIIt tM sa~~pled are than once in 10 yn Define whbullt h conlidered a bullliampnificant bull inc run in PCBbull in udtntbull middot

Section t o i)raabull 9- U firat pua8nph on paae 6-115 it h bullntioned that

bullolldification ahould reduce the 110bility hen it h stated that it pound_pnnenth nduce the 110bility clarify this issue In addition it is Mntioned that lona-tena 110nitorlna nquirnu are iteMhed llthouah the cost nf lon1 - terM MOnitorinl for this llternative h nearly equll to that of SC-11

In conc lusion bec1un of t he c0111plea AIAih inue11 nhed by t he p1rtlculu cOMblnbulltion of contaMinant s 1t thh lite the DIP bullnd EPA hbullve ten t1tlvely identified bulln d ternative which conlists of a cOMbinltion of nMdill bulllternativu which will aatisfJ bull11 AMit 1 Thh altern1tlve hu hPen outlined in EPAs Much l 1989 letter to CHP The DP reque1t1 th1t the Find FS contain 1 detaihd enluation of thh alternative 10 volue and co1t COMplrhonl can be Mlde Thh evaluation cbulln be incorporated into the exhtlna IC-11 Alternative

41 Paae 5-20 hat pansnph it is ponible that the PCB contalftinatlon in HW-1015A vu due to udi~~~ent lnflltntion durin11 well inttalhtion but this cannot be conclullively 11tated at this time The poulbllty that HW-1015A maybe contaminated mutt be considered when delignlng a groundwater tratment tysteM

5) Page 5-21 second )lllraRraph what signifigance tloes thh laboratory contudnation ha ve t o the overall QAQC for th e lab

Section 70 i~-4 fi ut paragraph change t he reference to buve r daM u thlll

da111 h ac tually ~~~an-made

21 Tabl e 7-1 indicate the unit s (ppbpplll) n pruented hue

Section 11 0 iJ--cr-1 Overall the presentation of thh Mlterial it poor There

are nueroua graiiiJIIItical at well u factual erron thoroughout this section uat be reviewed anti rewritten by IOIMIOOe ex perience d in bioloaical aStellllllnt t

21 Paae 11-7 third paragraph fifth untence botto 5 what

ll Paabull 11 - 9 ucond paraaraph indicate that the fiah obnrved in Ug111 lrook calM fr~ only a bullbull11 portion of the brook Larau older fiah alhdampedly exist farther downatreabull

4) Paabull 8-17 lut paragraph delete the word bull rtebull in nference to the backaround ttation bullbull it blpllebull a areater diatance than actually edata

5) Paae 1-19 top of paae firat tentence bullkebull no unu

6) Paabull 11-19 fint full pan1raph include hen that in addition to dUentinina if there vaa (is) a public h lth threat one or the objecthet vat to deterine if then wu an environMntal threat

7) Paabullbull 11 - 19 to 11 - 21 overlaJplnl untence bullke no unu txpldn how bullhed Jnduttry (which in particular) and farina could lead to low hveh of PCBs in back1round bullbullbullpies

II Paae 8 - 25 top o r paae end or sentence should thh read and other carnivores bull 7

9) Page 8 - ll last para1raph t he on-site h1oon t ve re no t con11 tructed dudna interiM re~~t~dhl act ionsbull and conlidered vetlands

101 Pa1bullbull 11 -33 - l-14 Specify which section or Rigas hook wetland h bdnamp evalua ted here The func tiond attributes dnwnatrea111 or the OConnor Site are probably quite dHrerent t han t hou adjacent to the Site

Section 90 iJP~-10 tecond tel of bullets add bullampration of toil particles

throuah joints in upper tilty ca ly u a potential bulllaration pathway

2) hse 9-27 ncnnd comple te bullet include Rina Brook ae diiiMnta 11 a receptor of site-derived PCB a

Section 10 i--middot--p~-i-22 first full paragraph 14- dichlornbenzene did excPed the

State o f Hline drinking water 1tandards on a number of occui ons

2) Pases 1-24 - 1-215 over lapping sentence this statement c annot be Made bued nn t he limited biota studies conducted at the OConnor Site

Section 2 0 ~jei-u first full p111ragraph in~ cues Hline hu adopted HCIa

11 ita drinking water standa rdbull but hu set 1tandarda lower t han HCLa in other cuu In additinn 1 4-dich1orobenune dou exceed Haine standards on a nuMber of occaaiona shy

Section l O i)-pbullleJ-115 1ut puagraph ~Iaine drinkina water atandard for

1 4-dich1orobenzene 11 27 ua1

Section 00 r-pa-e-152 lut u nt ence provide a rationale for ng_ perfor-ina

bulltala analysis in the 1t0nitortna progr for thh Alternative

Section 7 0 l)Palbull 7-Z rractun11 in hedror k provide dhtinct preferential pathways

or network s dona which contawlinatlnn NJ bulliarate wherea s bulliaration

~r=~~ ~c~ r~~~dmiddot~ank~rlt =~i~ertt~r the loc ation danaitJ orien t ation pen~eabUity and inte rconnec tion of fractures a t the site to justify the a nU~~ption that Milration patterns in the bedrock re ullble t hou in an unconso l1dated Media In addition to ina ta llin8 1t0n anitorinamp velh Jordan -uat consider the uu of borehole aeophyaica and other bullthod e to evalua te t he bedrock fracture 1y11tM and its affect on site hJdroloiJ contaMinant bull i aration and reMediation It h pouible t ha t thia work can occur durinamp the RIIMdial Oeaian phase

2) Paaea 7-l - 7-4 it IIUSt be deterMined how PCB a are Mia rating to and via ar-oundwater - aa an i11111hcible oil phue and or- attached to udtent particlu

]) P111ge 7-20 Injection velh are not allowed fnt dhch111q~Jog hnatdoua vute in Haine (lll H l S A Chaplet 54l - lulaa to control the aubaurhce dhchuaea of pollutbullntl by well injection) The dhchuaed wa ter would have to Met all 1tate drinkina water- atandarda bdote injection would be allowed

41 P11e1 7-21 - 7-29 ln loc1ting the rumiddotopond sroundw1ter u tr1ction wdl Jordan h1 11 over-llia~pllfied and senerelhed the libulllted geolo1ic and hydrolotplc d1t1 th1t hu been g1thered 10 fer For in1t1nce Flsure 7-2 1hould revel th1t the prennce and thicknu~t of the haul till h known frDIII welh 1t HW-101 1nd 103 well HW- 1068 1ntl test pit TP-116 not th1t the till forms 1 continuous hyer over lyinamp the bedrod--Connect inR the dot s between the known datbull polnt ~t h not ev idence thbullt t he intupret1tlon bullctu1lly ui1t1 in the field Another ex111111le h the statement on rbull1e 7-21 that genenl grflundwater flow at the dte h frOM northwe1t to southwest Section 5 of the RI spbullclficl lly 1t1tU th1t groundwater flows from north tn 1out h in the ovuburden bullnd 1110re e terly in the bedrock In addition while the proposed extraction well EW-1 1111y be 1uccenful in intercepting 1nd re110ving contabullinbullted aroundwbullter the nhting lklnitorinamp well nbulltwork with the addition of HW-107A bullnd B h not 1dequate to dbullterbullinbull its prognn Nw p1in or clubulltbulln of wells u1t be atrateaicbulllly located both inlidbull and outlide the utMited boundbullrin of the plUM 1nd c1pture aonu to deterMine if the aroundwbullter eatnction IJi t ebull h auccenful In partic uhr 110nitorins welh JMJit be in1t1lled in bullre northu1t Ult 1nd aoutheut of the ntraction u Thh h puticuhrly i11port1nt since Fiaure bull-bull in the ll 1howa bedrock outcropbull in TWA HI where the hiahut concentntion of PCBI (200000 ppM) in 1urhce soil bull occ ur but only 110nitorina welh 105A and 1051 ere clou to beln1 down andlent of then hot spots Thue are no aroundw1ter d1t1 northerlJ and eute rly of TWA III

Section 1 0 i---a-i-4 fir 1 t full plrllrl(lh biota MUIIt tM sa~~pled are than once in 10 yn Define whbullt h conlidered a bullliampnificant bull inc run in PCBbull in udtntbull middot

Section t o i)raabull 9- U firat pua8nph on paae 6-115 it h bullntioned that

bullolldification ahould reduce the 110bility hen it h stated that it pound_pnnenth nduce the 110bility clarify this issue In addition it is Mntioned that lona-tena 110nitorlna nquirnu are iteMhed llthouah the cost nf lon1 - terM MOnitorinl for this llternative h nearly equll to that of SC-11

In conc lusion bec1un of t he c0111plea AIAih inue11 nhed by t he p1rtlculu cOMblnbulltion of contaMinant s 1t thh lite the DIP bullnd EPA hbullve ten t1tlvely identified bulln d ternative which conlists of a cOMbinltion of nMdill bulllternativu which will aatisfJ bull11 AMit 1 Thh altern1tlve hu hPen outlined in EPAs Much l 1989 letter to CHP The DP reque1t1 th1t the Find FS contain 1 detaihd enluation of thh alternative 10 volue and co1t COMplrhonl can be Mlde Thh evaluation cbulln be incorporated into the exhtlna IC-11 Alternative

2) hse 9-27 ncnnd comple te bullet include Rina Brook ae diiiMnta 11 a receptor of site-derived PCB a

Section 10 i--middot--p~-i-22 first full paragraph 14- dichlornbenzene did excPed the

State o f Hline drinking water 1tandards on a number of occui ons

2) Pases 1-24 - 1-215 over lapping sentence this statement c annot be Made bued nn t he limited biota studies conducted at the OConnor Site

Section 2 0 ~jei-u first full p111ragraph in~ cues Hline hu adopted HCIa

11 ita drinking water standa rdbull but hu set 1tandarda lower t han HCLa in other cuu In additinn 1 4-dich1orobenune dou exceed Haine standards on a nuMber of occaaiona shy

Section l O i)-pbullleJ-115 1ut puagraph ~Iaine drinkina water atandard for

1 4-dich1orobenzene 11 27 ua1

Section 00 r-pa-e-152 lut u nt ence provide a rationale for ng_ perfor-ina

bulltala analysis in the 1t0nitortna progr for thh Alternative

Section 7 0 l)Palbull 7-Z rractun11 in hedror k provide dhtinct preferential pathways

or network s dona which contawlinatlnn NJ bulliarate wherea s bulliaration

~r=~~ ~c~ r~~~dmiddot~ank~rlt =~i~ertt~r the loc ation danaitJ orien t ation pen~eabUity and inte rconnec tion of fractures a t the site to justify the a nU~~ption that Milration patterns in the bedrock re ullble t hou in an unconso l1dated Media In addition to ina ta llin8 1t0n anitorinamp velh Jordan -uat consider the uu of borehole aeophyaica and other bullthod e to evalua te t he bedrock fracture 1y11tM and its affect on site hJdroloiJ contaMinant bull i aration and reMediation It h pouible t ha t thia work can occur durinamp the RIIMdial Oeaian phase

2) Paaea 7-l - 7-4 it IIUSt be deterMined how PCB a are Mia rating to and via ar-oundwater - aa an i11111hcible oil phue and or- attached to udtent particlu

]) P111ge 7-20 Injection velh are not allowed fnt dhch111q~Jog hnatdoua vute in Haine (lll H l S A Chaplet 54l - lulaa to control the aubaurhce dhchuaea of pollutbullntl by well injection) The dhchuaed wa ter would have to Met all 1tate drinkina water- atandarda bdote injection would be allowed

41 P11e1 7-21 - 7-29 ln loc1ting the rumiddotopond sroundw1ter u tr1ction wdl Jordan h1 11 over-llia~pllfied and senerelhed the libulllted geolo1ic and hydrolotplc d1t1 th1t hu been g1thered 10 fer For in1t1nce Flsure 7-2 1hould revel th1t the prennce and thicknu~t of the haul till h known frDIII welh 1t HW-101 1nd 103 well HW- 1068 1ntl test pit TP-116 not th1t the till forms 1 continuous hyer over lyinamp the bedrod--Connect inR the dot s between the known datbull polnt ~t h not ev idence thbullt t he intupret1tlon bullctu1lly ui1t1 in the field Another ex111111le h the statement on rbull1e 7-21 that genenl grflundwater flow at the dte h frOM northwe1t to southwest Section 5 of the RI spbullclficl lly 1t1tU th1t groundwater flows from north tn 1out h in the ovuburden bullnd 1110re e terly in the bedrock In addition while the proposed extraction well EW-1 1111y be 1uccenful in intercepting 1nd re110ving contabullinbullted aroundwbullter the nhting lklnitorinamp well nbulltwork with the addition of HW-107A bullnd B h not 1dequate to dbullterbullinbull its prognn Nw p1in or clubulltbulln of wells u1t be atrateaicbulllly located both inlidbull and outlide the utMited boundbullrin of the plUM 1nd c1pture aonu to deterMine if the aroundwbullter eatnction IJi t ebull h auccenful In partic uhr 110nitorins welh JMJit be in1t1lled in bullre northu1t Ult 1nd aoutheut of the ntraction u Thh h puticuhrly i11port1nt since Fiaure bull-bull in the ll 1howa bedrock outcropbull in TWA HI where the hiahut concentntion of PCBI (200000 ppM) in 1urhce soil bull occ ur but only 110nitorina welh 105A and 1051 ere clou to beln1 down andlent of then hot spots Thue are no aroundw1ter d1t1 northerlJ and eute rly of TWA III

Section 1 0 i---a-i-4 fir 1 t full plrllrl(lh biota MUIIt tM sa~~pled are than once in 10 yn Define whbullt h conlidered a bullliampnificant bull inc run in PCBbull in udtntbull middot

Section t o i)raabull 9- U firat pua8nph on paae 6-115 it h bullntioned that

bullolldification ahould reduce the 110bility hen it h stated that it pound_pnnenth nduce the 110bility clarify this issue In addition it is Mntioned that lona-tena 110nitorlna nquirnu are iteMhed llthouah the cost nf lon1 - terM MOnitorinl for this llternative h nearly equll to that of SC-11

In conc lusion bec1un of t he c0111plea AIAih inue11 nhed by t he p1rtlculu cOMblnbulltion of contaMinant s 1t thh lite the DIP bullnd EPA hbullve ten t1tlvely identified bulln d ternative which conlists of a cOMbinltion of nMdill bulllternativu which will aatisfJ bull11 AMit 1 Thh altern1tlve hu hPen outlined in EPAs Much l 1989 letter to CHP The DP reque1t1 th1t the Find FS contain 1 detaihd enluation of thh alternative 10 volue and co1t COMplrhonl can be Mlde Thh evaluation cbulln be incorporated into the exhtlna IC-11 Alternative

41 P11e1 7-21 - 7-29 ln loc1ting the rumiddotopond sroundw1ter u tr1ction wdl Jordan h1 11 over-llia~pllfied and senerelhed the libulllted geolo1ic and hydrolotplc d1t1 th1t hu been g1thered 10 fer For in1t1nce Flsure 7-2 1hould revel th1t the prennce and thicknu~t of the haul till h known frDIII welh 1t HW-101 1nd 103 well HW- 1068 1ntl test pit TP-116 not th1t the till forms 1 continuous hyer over lyinamp the bedrod--Connect inR the dot s between the known datbull polnt ~t h not ev idence thbullt t he intupret1tlon bullctu1lly ui1t1 in the field Another ex111111le h the statement on rbull1e 7-21 that genenl grflundwater flow at the dte h frOM northwe1t to southwest Section 5 of the RI spbullclficl lly 1t1tU th1t groundwater flows from north tn 1out h in the ovuburden bullnd 1110re e terly in the bedrock In addition while the proposed extraction well EW-1 1111y be 1uccenful in intercepting 1nd re110ving contabullinbullted aroundwbullter the nhting lklnitorinamp well nbulltwork with the addition of HW-107A bullnd B h not 1dequate to dbullterbullinbull its prognn Nw p1in or clubulltbulln of wells u1t be atrateaicbulllly located both inlidbull and outlide the utMited boundbullrin of the plUM 1nd c1pture aonu to deterMine if the aroundwbullter eatnction IJi t ebull h auccenful In partic uhr 110nitorins welh JMJit be in1t1lled in bullre northu1t Ult 1nd aoutheut of the ntraction u Thh h puticuhrly i11port1nt since Fiaure bull-bull in the ll 1howa bedrock outcropbull in TWA HI where the hiahut concentntion of PCBI (200000 ppM) in 1urhce soil bull occ ur but only 110nitorina welh 105A and 1051 ere clou to beln1 down andlent of then hot spots Thue are no aroundw1ter d1t1 northerlJ and eute rly of TWA III

Section 1 0 i---a-i-4 fir 1 t full plrllrl(lh biota MUIIt tM sa~~pled are than once in 10 yn Define whbullt h conlidered a bullliampnificant bull inc run in PCBbull in udtntbull middot

Section t o i)raabull 9- U firat pua8nph on paae 6-115 it h bullntioned that

bullolldification ahould reduce the 110bility hen it h stated that it pound_pnnenth nduce the 110bility clarify this issue In addition it is Mntioned that lona-tena 110nitorlna nquirnu are iteMhed llthouah the cost nf lon1 - terM MOnitorinl for this llternative h nearly equll to that of SC-11

In conc lusion bec1un of t he c0111plea AIAih inue11 nhed by t he p1rtlculu cOMblnbulltion of contaMinant s 1t thh lite the DIP bullnd EPA hbullve ten t1tlvely identified bulln d ternative which conlists of a cOMbinltion of nMdill bulllternativu which will aatisfJ bull11 AMit 1 Thh altern1tlve hu hPen outlined in EPAs Much l 1989 letter to CHP The DP reque1t1 th1t the Find FS contain 1 detaihd enluation of thh alternative 10 volue and co1t COMplrhonl can be Mlde Thh evaluation cbulln be incorporated into the exhtlna IC-11 Alternative

Tlhbilitr Studr Tha DeputMnt finds the solvent extnction tnatability study ac cP ptable

fol shovina that thh technology will olk at the OConnol Site Hownu durinK tha leewdid Design phue of this ploject IIIOte infOINtion N) be nquitad includina infotNtion teanding ruidud TEA leveh in bull oils and the effect on othu aoil conta111inant1

If you have eny quu tionbull reaardina then coanent1 pleue contact Me

~_A~ CYNTHIA H KUHNS Division of Licensing EnforceMent lunau of Oil Hnardou1 -teriah Control

CHIIdjp cktowt

Hike Jintky EPA Jbull Vallaca EC Joldan Co

1. barcode 567194
2. barcodetext SDMS Doc ID 567194