# PROPOSE

D N O ACTION PLA N FO R STOCKPILE D FIN E SLA G U.S. Environmenta l Protectio n Agency Regio n VII I
,

; -' " Septembe r 199 6 Arkansas Valle y Smelte r Sla g Pil e Californi a Gulc h Superfun d Site Leadville

, Colorad o 

### 38914 1 

# EP A Announce s It s Preferre d Alternativ e T h e U.S

. Environmenta l Protectio n Agenc y (EPA ) request s publi c commen t o n it s preferre d alternativ e fo r stockpile d fin e sla g a t die Arkansas Valle y smelte r sla g pil e o f Operabl e Uni t 3 (OU3 ) withi n th e Californi a Gulc h Superfun d Sit e i n Leadville

, Colorado

. EP A i s th e lea d agenc y an d i s assiste d b y th e Colorad o Departmen t o f Publi c Healt h an d Environmen t (CDPHE)

, whic h i s th e sup

por t agenc y a t thi s site

. Th e preferre d alternativ e fo r stockpile d fin e sla g a t th e Arkansa s Valle y sla g pil e i s "N o Action, " wit h a contin

genc y fo r futur e utilizatio n o f th e slag
, a s describe d mor e full y late r i n thi s plan

. EP A recommend s thi s alternativ e base d o n th e result s o f th e ris k assessmen t an d afte r a care fu l evaluatio n o f sit e data

. Th e CDPH E ha s reviewe d thi s pla n an d concur s wit h th e propose d approach

. Thi s Propose d

Pla n fulfill s th e requirement s o f th e Comprehensiv e Environmenta l Respons e Compensation

, a n d Liabilit y Ac t (CERCLA ) Sectio n 11 7 (a ) (notic e o f availability)

. Thi s Propose d Pla n summarize s informatio n that ca n b e foun d i n greate r detai l i n th e Final Stockpiled Fine Slag Feasibility Study Report (FS)

, whic h i s availabl e fo r you r revie w a t th e informatio n repositorie s liste d below

. Th e Propose d Pla n i s base d o n th e conclusion s o f th e F S an d applie s onl y t o th e stockpile d fin e sla g a t th e Arkansa s Valle y pile

. Durin g th e remedia l investigation , sit e dat a wer e use d t o asses s th e viabilit y o f fiv e potentia l contami

nan t releas e mechanism s (o r transpor t pathways ) identifie d i n th e conceptua l sit e mode l (CSM ) fo r th e sla g piles : wind
, leaching
, mixin g b y huma n activities , runof f o f particulates
, 

### MAR K YOU R CALENDAR : OPPORTUNITIE S

FO R PUBLIC INVOLVEMEN T Publi c Meeting : Thursday, Octobers, 1996, 7:00p.m. Nationa l Minin g Hal l o f Fam e an d Museu m (10t h Stree t Entrance ) Leadville

, Colorad o Publi c Commen t Period : Septembe r 2 7 - October 28 , 199 6 Sen d Comment s to : Rebecca Thoma s (8EPR-SR ) EP A Remedia l Projec t Manage r 99 9 18t h Street

, Suit e 50 0 Denver

, Colorad o 80202-240 5 

### K e y Contacts : Rebecca Thoma s E P A Remedia l Projec t Manage r (303)312-655 2 Toll-fre e (800 ) 227-891 7 x 655 2 Russel l Alie n CDPH E Stat e Projec t Office r (303 ) 692-338 2 Informatio n Repositories : The Proposed Plan and other documents in the Administrative Record are available at the following locations: Lake County Public Library 111 5 Harriso n Avenu e Leadville

, Colorad o 8046 1 Colorado Mountain College Library Learnin g Resourc e Cente r Leadville

, C O 8046 1 EPA Superfund Records Center 99 9 18t h Stree t 5 t h Floor
, Nort h Terrac e Denver

, C O 8020 2 (303 ) 312-647 3an d direct contact

. O f these
, onl y on e potentia l releas e mechanism
, leaching
, was retaine d fo r th e sla g piles

. 

### Therefore
, a remedial actio n objectiv e wa s establishe d t o preven t leachin g o f metal s o f concer n i n concentration s tha t woul d hav e a n advers e impac t o n soils
, surfac e water , o r groundwate r i n th e are a nea r th e sla g piles

. Th e F S report provide s a detaile d analysi s o f th e thre e alter

natives considere d fo r stockpile d fin e sla g a t th e Arkansa s Valle y pile

. Thes e alternatives
, whic h wer e retained follow

in g screenin g i n 1993 , ar e n o action , institutiona l controls
, and resourc e utilization

. EP A encourage s communit y involvemen t i n th e remed y selectio n process an d invite s publi c commen t o n al l alternatives

. 

### PUBLI C INVOLVEMEN

T PROCES S EP A encourage s resident s an d other intereste d partie s t o rea d an d commen t o n thi s Propose d Plan

, th e Final Report for Lead Slag Pile Remedial Investigation at the California Gulch Site, Leadville, Colorado (RI)

, an d th e F S

. Thes e document s describ e th e result s o f sit e investi

gation s an d th e cleanu p alternative s considered

. Th e Propose d Pla n i s base d o n finding s o f th e RI

, th e FS

, an d othe r pertinen t documents

. Thes e report s ar e locate d i n th e informatio n repositories an d ar e include d i n th e Administrativ e Recor d fo r th e Californi a Gulc h Superfun d Site

. Th e Administrativ e Recor d contain s al l


### o f th e informatio n upo n whic h th e selectio n o f th e reme d y wil l b e based

. EP A wil l mak e it s fina l remed y selectio n onl y afte r con siderin g al l stat e and communit y comments

. EP A ma y modif y th e preferre d alternative
, selec t anothe r alterna

tiv e presente d i n thi s plan
, or selec t a mor e appropriat e alternativ e base d o n ne w informatio n o r publi c com 

### ments

. EP A encourage s th e publi c t o revie w an d com 

### men t o n al l identifie d alternatives
, a s wel l a s t o provid e a ny ne w informatio n fo r EPA' s consideration

. Late r thi s year , EP A wil l publis h a Recor d o f Decisio n (ROD ) tha t respond s t o communit y comment s an d document s EP A Announce s Preferre d Alternativ e ................. .

.p

. 1 Publi c Involvemen t Process ........p

. 2 Sit e Backgroun d

.............. .

.p

. 2 Assessmen t o f Sit e Risk s
....... . .p

. 5 Summar y o f Alternative s ..........p

. 7 Cleanu p Evaluatio n Criteri a .......p

. 8 Compariso n an d Evaluatio n o f Alternative s ................p

.

9 Descriptio n o f Preferre d Alternativ e ................. .

.p

. 9 Acronyms/Glossar y ............ .

.p

. 1 0 th e rational e fo r it s decision

. Th e RO D wil l contai n responses t o comment s o n th e Propose d Plan

. 

### Thi s Propose d Pla n i s prepare d t o fulfil l EPA' s publi c par



### ticipatio n responsibilitie s under Section s 113(k ) an d 117(a ) o f th e Comprehensiv e Environmenta l Response

, Compensation

, an d Liabilit y Ac t (CERCLA ) o f 1980 , a s amende d b y th e Superfun d Amendment s an d Reauthorizatio n Ac t (SARA ) o f 1986

. 

### Comment s o n th e Propose d Pla n an d F S ma y b e submit



### te d either orall y o r i n writin g a t th e Octobe r 3,199 6 pub

li c meeting , o r yo u ma y sen d writte n comments , post

marke d n o late r than Octobe r 28 , 1996 , t o Rebecc a Thoma s a t th e addres s provide d on pag e 1

. Upo n timel y request , th e commen t perio d ma y b e extended

. Suc h 

### request s shoul d b e submitte d i n writin g t o Rebecc a Thoma s a t th e EP A addres s provide d o n pag e 1 an d mus t b e postmarke d n o late r tha n Octobe r 28 , 1996

. 

### SIT E BACKGROUN D Sit e History

. Th e Californi a Gulc h Superfun d Sit e (here

after
, th e site ) i s locate d i n an d aroun d th e communit y o f Leadville

, Colorado

, abou t 10 0 mile s southwes t o f Denver (Figur e 1)

. Beginnin g i n abou t 1860 , th e Leadvill e are a wa s use d extensivel y fo r mining , milling
, 

### an d smeltin g operations

. Silver

, gold
, copper , lead
, an d zin c wer e mine d b y undergroun d an d place r method s 

### fro m withi n th e site

. Approximatel y 1 7 smelte r facilitie s ar e reporte d t o hav e onc e operate d o n site

. Mos t opera

tion s cease d b y abou t 1900 , althoug h som e facilitie s con tinue d t o operat e int o th e 1920's , suc h a s Wester n Zinc
, 

### an d th e int o th e 1960's , suc h as th e Arkansa s Valle y Smelter

. A t present , nearl y al l o f th e mine s within th e sit e boundarie s are inactive ; onl y a fe w smal l t o moderate

size d minin g operation s exist

. Al l o f th e mill s an d 

### smelter s onc e situate d o n sit e hav e bee n demolished

. Du e t o histori c mining , milling
, an d smeltin g operations , t h e sit e contain s man y tailing s impoundments
, fluvia l 

### deposits
, sla g piles
, wast e roc k piles
, an d min e water drainag e tunnels

. Sla g o n sit e i s th e mineralize d wast e byproduc t o f smeltin g an d result s fro m th e processin g o f lea d or e i n hig h temperatur e furnaces

. Thre e majo r sla g 

### pile s an d severa l smalle r pile s remai n a t th e sit e (Figur e 2)

. I n 1961 , th e Denve r an d Ri o Grand e Wester n Railroa d (D&RGW ) purchase d th e Arkansa s Valle y sla g pil e fro m ASARC O fo r us e a s railroa d ballast

. D&RG W 

### purchase d th e L a Plat a sla g pil e fro m th e Leadvill e Sanitatio n Distric t i n 1970

. Additionally
, D&RG W pur

chase d th e Harriso n Stree t Sla g Pil e fro m N L Industrie s

## Leadvill

e California Gulch NPL Site 

# Lak e Count y

Leadvllle/» r

! CONTINENTA L

DIVID E 

## FIGUR E

1 

## Genera l Sit e Locatio n j:\calgulch\12d24800\wp\lakemap3.ep s U )

# - - f asr 1-——-k

I I lOPOCWPH C CONTOUD S " » SURFAC E FEA1URC S PROVDE D BT INTRASCARC H J

FIGUR E 2 SLA G PIL E LOCATIO N MA P Source : TERRANEX

T 199 6

### i n 1983

. Thi s Propose d Pla n addresse s onl y fin e sla g stockpile d a s a subpil e o f th e Arkansa s Valle y sla g pile

. Regulator y History

. I n 1983 , ERA

. place d th e Californi a Gulc h sit e o n th e Nationa l Prioritie s Lis t (NPL)

, because o f concern s abou t th e impac t o f min e drainag e o n surfac e 

### water s i n th e Californi a Gulch an d th e impac t o f heav y metal s loadin g t o th e Arkansas River

. Subsequen t investi

gation s reveale d th e presenc e o f heav y metal s i n soil s an d 

### wast e pile s i n an d aroun d residentia l an d commercia l
area s o f Leadville

. A preliminar y ris k assessment indi

cate d tha t contaminan t levels
, particularl y level s o f arseni c an d lead
, wer e hig h enoug h t o b e o f potentia l huma n healt h concern . O n December 3,1991 , EP A an d D&RG W entered int o a n 

### Administrativ e Orde r o n Consent (AOC ) fo r th e perfor

- manc e o f a remedia l investigation/feasibilit

y stud y 

### (RI/FS ) o f th e lea d sla g piles

. Prio r t o th e AOC

, EP A ha d studie d th e sla g pile s a s par t o f othe r investigations a t th e 

### site

. I n 1992 , D&RG W performe d an R I that addresse d seve n lea d sla g piles
, includin g th e Arkansa s Valley
, Harrison
, an d L a Plat a sla g piles
, an d on e zin c sla g pile

. Followin g th e RI

, a Site-Wid e Screenin g Feasibilit y 

### Stud y (SFS ) wa s undertake n a s a join t effor t betwee n th e potentiall y responsibl e partie s an d EPA

. Th e SF S wa s 

### complete d i n Marc h 1993

. I t screene d severa l remedia

tio n alternative s fo r al l type s o f sla g locate d o n th e sit e base d o n specifi c criteria , suc h a s relativ e cost , imple

- 

### mentability
, an d effectiveness

. Th e thre e retaine d alter

natives fo r furthe r evaluatio n were : no action , institu

tiona l controls
, an d resourc e utilizatio n (material s reuse)

. O n Decembe r 15 , 1993 , D&RG W entere d int o a Consen t Decre e wit h EP A t o perfor m the remainde r o f thei r sit e work

. Th e consen t decree state d EPA' s concern s regard

in g th e fin e fractio n o f th e stockpile d sla g an d th e poten



### tia l fo r paniculat e releas e durin g ballas t operation s as a potentia l huma n healt h exposur e pathway

. Th e consen t decre e require d D&RG W t o perfor m a feasibilit y stud y fo r stockpile d fin e sla g an d t o submi t a n operation s pla n befor e initiatin g an y ballas t operations

. I n Jul y o f 1995 , 

### D&RG W submitte d a ballas t operation s pla n t o EPA

. Followin g EPA' s approva l o f th e plan
, ballas t operation s commence d i n Augus t 1995

. Ballas t operation s involv e th e sortin g o f large r sla g s o tha t th e siz e fractio n o f greate r than 3/ 8 inc h an d les s than 2 1/ 2 inche s i s pro

duce d fo r railroa d ballast

. Th e undersize d fractio n (i.e.
, 

### les s than 3/ 8 inch)
, o r sorte d fin e slag
, that i s produce d b y th e sortin g proces s i s stockpile d alon g wit h th e previous

l y sorte d fin e sla g a t th e Arkansa s Valle y pile

. 

### Durin

g th e earl y par t o f 1995 , a baselin e huma n healt h ris k assessmen t wa s undertake n tha t furthe r assesse d 

### potentia l huma n healt h risk s fro m exposur e t o heav y met

al s a t the site

. A resul t o f the fina l baselin e ris k assess



### men t wa s a Propose d N o Actio n Pla n fo r commercia l an d recreational lan d use s at th e site

. The Propose d Pla n addresses area s withi n th e sit e currentl y zone d commer 

### cial/industria l an d area s use d fo r non-residentia l recre ationa l purposes

. Fiv e commercial/industria l

area s at the site , includin g th e Arkansa s Valle y sla g pile
, wer e specif



### icall y exclude d fro m th e 199 5 Propose d N o Actio n Pla n 

### becaus e o f concern s relate d t o hig h level s o f lead

. Tw o othe r propertie s withi n OU3
, th e forme r D&RG W rail

yar d an d th e easemen t throug h town , wer e include d i n th e 

### area s whic h carr y th e n o actio n designation

. Th e con centrations o f lea d i n soil s withi n the railyar d wer e belo w th e leve l o f concern , althoug h D&RG W ha s identifie d a 

### smal l are a wit h fin e sla g i n th e railyard

. D&RG W ha s prepare d a pla n whic h addresse s remova l and contro l o f 

### fin e sla g fro m thi s area . Th e fin e sla g i s t o b e remove d 

### fro m th e railyar d an d consolidate d wit h th e stockpile d fin e sla g a t th e Arkansas Valle y pile

. Th e easemen t throug h tow n wa s evaluate d an d determine d no t t o con tai n concentrations o f lea d whic h woul d b e o f concer n i n a recreationa l setting

. A s lon g a s lan d us e remain s recre ational o r commercial/industrial

, n o actio n wil l b e neces

sary
. I n Ma y o f 1996 , D&RG W submitte d a feasibilit y stud y f o r th e stockpile d fin e sla g (th e FS ) a t th e Arkansa s Valle y pile
, accordin g t o th e term s o f th e Consen t Decree

. Th e existin g fin e sla g subpil e an d fin e sla g potentiall y gener ated fro m futur e ballas t productio n wer e th e focu s o f th e F S

. Th e F S provide d a detaile d analysi s o f th e three retaine d remediatio n alternative s fro m th e SF S a s applie d 

### t o th e stockpile d fin e slag

. 

### ASSESSMEN T O F SIT E RISK S T h e preliminar y ris k assessmen t identifie d lea d an d arseni c a s th e primar y chemical s o f potentia l concer n a t th e site

. Sinc e th e completio n o f th e preliminar y ris k 

### assessment , severa l importan t studie s wer e complete d tha t provide d mor e extensiv e an d mor e reliabl e dat a on environmenta l concentration s an d on human exposures

. Therefore
, a baselin e huma n healt h ris k assessmen t was complete d t o incorporat e al l reliabl e dat a int o a fina l ris k assessmen t fo r th e site : Par t A evaluate s risk s t o resident s fro m lead ; Par t B evaluate s risk s t o resident s fro m met

al s othe r tha n lead ; an d Par t C evaluate s risk s t o worker s i n th e commercial an d busines s distric t an d t o recreation

a l user s i n area s i n an d aroun d th e community

. Th e fol

5

### lowin g paragraph s summarize result s o f th e fina l baselin e ris k assessmen t a s the y relat e t o the stockpile d fin e sla g a t th e Arkansa s Valle y pile

. 

### RESIDENTIA L RIS K ASSESSMEN T Exposur e pathways determine d t o b e th e mos t importan t fo r contac t wit h mine-relate d wast e at the sit e include d inadverten t ingestio n o f contaminate d soi l an d dust
, inad

verten t ingestio n o f materia l a t wast e pile s (suc h as , wast e rock
, tailings
, or slag)
, an d ingestio n o f impacte d ground

water

. Othe r pathway s o f exposur e t o mine-relate d wast e (i.e.
, inhalatio n o f airborn e particulates
, derma l contac t wit h contaminant s i n soi l o r dust
, ingestio n o f home



### grow n vegetables
, an d ingestio n o f fis h fro m contaminat



### e d surfac e waters ) wer e judge d t o b e sufficientl y mino r tha t quantitativ e evaluatio n wa s no t warranted

. Residentia l Exposur e t o Slag

. Th e evaluatio n o f expo

sur e t o contaminant s a t wast e pile s include d considera

tion o f sla g pil e data
, wit h a n exposur e scenari o conserv

ativel y evaluatin g a chil d playin g o n th e wast e pile s who 

### ma y com e int o contac t wit h contaminant s throug h inad

verten t ingestio n o r derma l (skin ) contact

. The derma l contac t pathwa y wa s determine d t o b e minima l an d wa s no t considere d further

. Th e residentia l ris k assessmen t als o determine d tha t non-lea d metal s i n mos t wast e pile s pos e eithe r n o ris k o r onl y lo w ris k fro m direc t contac t whil e playin g o n th e piles

. Fo r th e evaluatio n o f lea d 

### exposur e a t th e wast e piles
, th e dat a wer e foun d t o b e to o limite d t o derive reliabl e estimate s o f th e potentia l impac t o f direct exposure s t o childre n wh o play o n wast e piles ; however
, mode l estimate s suggeste d th e effec t coul d b e substantial
, dependin g o n th e concentratio n o f lead i n th e 

### wast e pil e an d th e frequenc y an d exten t o f contact

. I t wa s furthe r conclude d that wast e pile s ca n contribut e t o expo

sur e no t onl y throug h direc t exposur e t o childre n wh o 

### pla y o n th e piles
, bu t als o indirectl y b y servin g a s a sourc e o f lea d contaminatio n i n nearb y yard s an d home s 

### (contaminan t migratio n t o nearb y yard s an d home s b y transpor t o f airborn e particulates)

. 

### Win d erosio n an d direc t contact wer e no t considere d viabl e releas e mechanism s fo r th e stockpile d fin e sla g i n th e SFS

. However
, base d o n th e result s o f th e ris k assess

ment , EP A maintain s som e concer n abou t th e potentia l 

### f o r paniculat e releas e an d huma n exposur e shoul d resourc e utilizatio n o f th e stockpile d fin e sla g b e under

taken

. (Fo r example
, inhalatio n o f sla g particle s coul d


### occu r i f th e material i s disturbe d fro m it s curren t state)

. I f th e resourc e utilizatio n optio n i s exercised
, measure s 

### woul d b e required t o preven t contaminan t releases

. 6 

### Residentia l Exposur e t o Impacte d Groundwater

. Th e remedial actio n objectiv e i n the 199 3 SF S wa s t o prevent leachin g o f metal s o f concer n i n concentration s that 

### woul d hav e a n advers e impac t o n soils
, surfac e water , o r groun d wate r i n th e are a nea r th e sla g piles

. Whe n th e groundwate r exposur e pathwa y wa s evaluate d i n th e 199 6 

### fina l baselin e ris k assessment , dat a indicate d tha t inges

tio n o f th e water fro m th e shallo w aquife r beneat h som e o f th e larg e tailing s pile s alon g Californi a Gulc h woul d 

### b e o f ver y high concer n t o children

. However
, th e 199 6 F S determine d tha t testin g i n material unde r th e sla g pil e 

### di d no t indicat e tha t migratio n o f contaminant s b y leach

in g fro m th e sla g contribute s t o elevate d metal s beneat h th e sla g piles

. I n addition
, th e fina l baselin e ris k assess

men t determine d tha t groundwate r fro m thi s aquife r i s 

### no t currentl y use d for drinking
, an d i t i s relativel y unlike

l y tha t i t wil l b e use d for drinkin g i n th e future

. EP A ha s 

### determine d that ther e i s minima l potentia l fo r releas e o f metal s i n leachat e fro m the stockpile d fin e slag
, an d tha t th e stockpile d fin e sla g poses , at most , a n insignifican t impac t o n wate r quality

. 

### NON-RESIDENTIA L RIS K ASSESSMEN T Leadvill e official s an d busines s leader s expresse d con cer n abou t possibl e risk s an d liabilitie s associate d wit h commercia l an d recreationa l use s withi n th e site

. Therefore
, i n th e fina l baselin e ris k assessment , EP A evaluate d th e risk s pose d b y environmenta l contamina

tio n t o curren t o r futur e worker s i n th e commercia l an d busines s distric t o f th e communit y an d t o peopl e who engag e i n recreationa l activitie s i n area s i n an d aroun d 

### th e community

. Th e assessmen t wa s conducte d t o deter

min e i f environmenta l contaminatio n wa s o f concer n a t
an y sit e location s presentl y zone d commercial/industria l


### an d t o addres s concern s regardin g th e developmen t o f a propose d bik e pat h aroun d th e community

. 

### Recreationa l Use r Exposur e t o Slag

. Th e EP A pro

pose d n o actio n fo r non-residentia l recreationa l use s a t the sit e i n the 199 5 Propose d N o Actio n Plan

, base d o n a compariso n o f actio n level s derive d i n the ris k assessmen t 

### for recreationa l lan d use an d measured an d predicte d sur

ficia l soi l concentration s fo r bot h lea d an d arsenic

. Th e n o actio n respons e applie d t o al l area s o f th e sit e tha t are 

### use d fo r recreationa l activitie s suc h a s hiking
, biking
, hunting
, an d roc k hounding
, an d include d tha t are a o f th e sit e propose d fo r constructio n o f th e Minera l Bel t Bik e Path

. The sla g pil e are a i s situate d i n an are a presentl y zone d a s industrial/minin g an d i s no t considere d a recre ationa l us e area .

### Worke r Exposur e t o Slag

. The are a o f the Arkansa s Valley
, Harrison
, an d L a Plat a sla g pile s wer e excepte d fro m th e 1995 Propose d N o Actio n Pla n becaus e o f con cern s abou t extensiv e level s o f lea d an d potentia l expo

sur e t o worker s i n th e commercial/industria l

are a o f th e community

. Th e worke r ris k assessment use d th e fol

lowin g approach : • Lead an d arseni c wer e evaluate d a s th e chemical s o f concern . Eve n thoug h othe r metal s occu r a t increase d concentration s i n th e environmen t aroun d Leadville

, experienc e a t other sites , a s wel l a s result s o f preliminar y calculations
, indi

cate d that lead an d arseni c ar e th e "ris k drivers. "
• Th e ingestio n pathwa y wa s evaluate d a s th e majo r pathwa y o f concern . Exposur e t o soi l and dus t wa s evaluate d fo r workers

. Exposur e t o othe r medi a suc h a s wast e piles
, surfac e water , 

### an d sediment s an d exposur e t o soil/dus t vi a othe r pathway s suc h a s ski n contac t an d inhalatio n o f airborn e particulate s wer e considere d t o b e o f mino r concer n fo r workers

. • Because o f uncertainties regardin g actual level s o f exposur e o f workers
, EP A di d no t calculat e a singl e concentratio n (action level ) tha t woul d identif y a n are a a s bein g o f concern , bu t rathe r 

### calculate d a rang e o f soi l concentration s that coul d b e considere d protectiv e fo r the commer 

### cial/industria l lan d use
. Whil e al l o f th e values withi n the rang e ar e credible
, values fro m the centra l portio n wer e considere d t o b e mor e likel y appropriat e tha n value s a t th e lo w en d o r th e hig h end

. 

### • Th e potentia l fo r healt h risk s fo r lea d an d arseni c wa s evaluate d b y comparin g ris k level s fro m th e centra l portio n o f the rang e wit h map s showin g th e measure d or estimate d concentration s o f lea d
an d arseni c acros s th e site

. Area s wher e th e con 

### centration s wer e belo w th e centra l rang e o f ris k level s wer e judge d t o pos e n o unacceptabl e healt h risks
, whil e area s wit h potentia l fo r extensiv e 

### contaminatio n abov e the centra l range o f actio n level s wer e considere d t o b e o f concern, requirin g furthe r remedia l response

. I t i s als o importan t t o not e tha t i t i s th e averag e concentratio n ove r 

### define d exposur e area s tha t wa s compare d t o the decisio n criterion , rathe r than values measure d a t specifi c samplin g locations

. 

### For

evaluatio n o f lea d exposure , the ris k assessmen t focuse d o n femal e worker s wh o wer e pregnan t o r migh t becom e pregnant , based o n health-base d dat a that the fetu s o f a pregnan t worke r i s especiall y susceptibl e t o th e effect s o f lead

. I n orde r t o determin e lea d action levels
, the ris k assessment calculate d level s o f lea d i n soi l that woul d ensur e that th e mothe r woul d hav e a low chanc e o f havin g a bloo d lea d leve l tha t migh t expos e th e fetu s t o unacceptabl e level s o f lead

. Th e ris k assessmen t estimat

ed tha t lea d actio n level s fo r pregnant worker s coul d rang e fro m 2,20 0 part s pe r millio n (ppm ) t o 19,10 0 ppm , wit h centra l tendenc y value s i n th e 6,10 0 t o 7,70 0 pp m 

### range . Afte r comparin g th e centra l tendenc y level s t o measure d o r estimate d concentrations o f lea d i n soils
, EP A propose d n o actio n fo r commercia l use s o f the site , wit h th e exceptio n o f fiv e sit e area s includin g th e 

### Arkansa s Valle y sla g piles

. A lea d actio n leve l i n a commercial/industria l

applicatio n wa s propose d at 7,00 0 pp m i n the F S fo r remediatio n o f 

### soil s i n an d aroun d th e sla g piles

. Base d o n th e result s o f subsla g samplin g conducte d durin g th e RI

, th e maximu m concentration s o f lea d i n al l subsla g sample s wa s 79 4 milligrams pe r kilogra m (mg/k g i s equa l t o ppm)
, wel l 

### belo w th e lea d actio n level

. Actio n level s wer e determine d i n th e ris k assessmen t fo r arseni c i n soi l an d ranged fro m a s lo w a s 33 0 pp m t o a s hig h a s 1,300 ppm , wit h centra l tendenc y value s i n th e 61 0 t o 69 0 pp m range . The EP A determine d tha t ther e are n o identifie d area s within th e sit e whic h contai n arseni c a t level s o f concer n unde r a commercial/industri

a l scenario

. 

### SUMMAR Y OF ALTERNATIVE S A wid e rang e o f cleanu p option s wer e considere d i n th e SFS

. Som e wer e eliminate d durin g preliminar y screen

in g becaus e the y woul d no t effectivel y addres s contami



### nation , coul d no t b e implemented
, o r woul d hav e ha d excessiv e cost s compare d t o othe r protectiv e alternatives

. Followin g screening , thre e alternative s wer e retaine d fo r furthe r evaluatio n fo r th e fin e sla g sub-pil e o f th e Arkansa s Valle y smelte r sla g pile

. Thes e alternative s were : (1 ) n o action , (2 ) institutiona l control s an d fenc



### i n g o f th e stockpile d fin e slag
, (3 ) resourc e utilization

. Thes e alternative s wer e compare d an d evaluate d usin g EPA' s nin e evaluatio n criteri a describe d i n th e nex t section

.

### CLEANU P EVALUATIO N CRITERI A
The thre e alternative s retaine d fo r stockpile d fin e sla g wer e evaluate d i n the F S usin g the nin e criteri a summa

rized below

. I n assessin g alternatives
, al l mus t mee t Criteri a No

. 1 and No

. 2

.

1

. Overal l Protectio n o f Huma n Healt h an d th e Environmen t addresse s whethe r a remed y i s pro

tectiv e an d describes ho w risk s pose d throug h eac h pathwa y ar e eliminated
, reduced
, o r controlled

. 5

. Reductio n o f Toxicity
, Mobility
, or Volum e throug h Treatmen t refer s t o the preferenc e fo r a reme d y that reduce s healt h hazards
, th e movemen t o f contaminants , o r th e quantit y o f contaminant s a t th e sit e throug h treatment

.

2

.

3

. 

### Complianc e wit h Applicabl e o r Relevan t an d Appropriat e Requirement s (ARARs ) addresse s whethe r a remed y wil l mee t al l applicabl e federa l an d stat e envi

ronmenta l law s an d othe r relevan t an d appro

priat e requirement s and/o r provid e ground s fo r a waiver

.

Short-Ter m Effectivenes s address

e s th e perio d o f tim e neede d t o complet e th e remedy
, an d an y advers e effect s t o huma n healt h an d th e environmen t tha t ma y b e cause d durin g th e constructio n an d implementatio n o f th e remedy

. Implementabilit y refer s t o th e technica l an d administrativ e feasi

bilit y o f a n alternativ e o r a remedy

. I t include s th e availabilit y o f mate

rial s an d service s neede d t o carr y ou t a remedy

. I t als o include s coordinatio n o f federal
, state , an d local government s t o wor k togethe r t o clea n u p th e site

. Cos t Effectivenes s evaluate s th e estimate d capital
, operation , an d maintenanc e cost s o f eac h alter

nativ e i n compariso n t o othe r protectiv e alternatives

. Stat e Acceptanc e indicate s whethe r th e stat e agree s with
, opposes , o r ha s n o commen t o n th e preferre d alternative

.

4

. Long-Ter m Effectivenes s an d Permanenc e refer s t o th e abilit y o f
a remed y t o provid e reliabl e protec

tio n o f huma n healt h an d th e envi

ronmen t ove r time

. 9

.

Communit y Acceptanc e include s determinin g whic h component s o f th e alternative s intereste d person s i n th e communit y support , hav e reservation s about
, or oppose

. Thi s assessmen t ma y not b e complete d unti l publi c comment s on the propose d pla n ar e reviewed

.

### COMPARISO N

AN D EVALUATIO N 

### O F ALTERNATIVE S Th e F S wa s develope d t o addres s th e alternative s evalua

tio n fo r th e stockpile d fin e sla g a t th e Arkansa s Valle y sla g pil e a t th e site

. Th e F S performe d a detaile d analysi s o f t h e thre e alternatives retaine d fro m th e SF S usin g EPA' s 

### nin e evaluatio n criteria

. A summar y o f the analysi s o f
eac h retaine d alternativ e i s provide d below

. Alternativ e 1 ; N o Action

. Generally

, th e N o Actio n Alternativ e i s provide d fo r consideratio n a s a baselin e agains t whic h othe r technologie s ca n b e compared
, i n accordance wit h th e Nationa l Contingenc y Pla n (NCP)

. F o r th e stockpile d fin e slag
, th e N o Actio n Alternativ e i s 

### propose d t o leav e th e material i n plac e wit h n o remedia

tion , engineerin g controls
, institutiona l controls
, o r long

ter m maintenance

. N o action i s protectiv e o f huma n healt h an d th e environmen t an d i s considere d effectiv e becaus e n o complet e huma n exposur e pathway s wer e identifie d fo r th e stockpile d fin e sla g an d becaus e th e potentia l fo r releas e o f metal s i n leachat e fro m th e stock

pile d fin e sla g i s minimal

. Thi s alternativ e i s technicall y feasibl e an d cos t effective
, sinc e i t doe s no t rel y o n an y technolog y an d ha s n o cost

. Alternativ e 2 : Institutiona l Controls/Fencin

g o f th e Stockpile d Fin e Slag

. Institutiona l control s involv e restrictin g acces s o r activitie s that coul d increas e the potentia l fo r leachin g fro m stockpile d fin e slag
, fo r exam ple
, fencing
, land-us e restrictions , o r dee d restrictions

. Dee d restriction s ar e alread y recorde d fo r th e stockpile d fin e slag

. Th e optio n considere d i s t o fenc e an d maintai n t h e stockpile d fin e sla g locate d a t th e Arkansa s Valle y sla g pile

. Fencin g woul d eliminat e th e potentia l direc t contac t pathwa y wit h th e fin e sla g piles

. Fencin g woul d b e pro

tectiv e o f huma n healt h an d th e environmen t becaus e n o complet e huma n exposur e pathway s woul d exis t (tha t is , childre n woul d not hav e acces s t o the piles)
, and becaus e th e potentia l fo r releas e o f metal s i n leachat e fro m th e stockpile d fin e sla g woul d remai n minimal

. Fencin g 

### woul d b e technicall y feasible

. Cost s associate d wit h fenc



### in g ar e $161,00 0 wit h inspectio n and maintenanc e cost s o f $8,50 0 fo r a 30-yea r period

. Alternativ e 3 ; Resourc e Utilization

. Tw o option s fo r resourc e utilizatio n (material s reuse ) wer e identifie d i n th e F S : 1 ) t o proces s sla g fo r us e a s a concret e o r asphal t aggregat e i n construction , and 2 ) t o us e sla g material s for a stand-alon e materia l i n construction , suc h a s backfil l o r pip e bedding

. Resource utilizatio n woul d be protectiv e o f huma n healt h an d th e environment becaus e appropriat e environmenta l control s fo r particulate s emission s an d 

### stormwate r

woul d b e required t o contro l contaminan t releases

. Resourc e utilizatio n ma y marginall y decrease th e minima l metal s concentrations i n th e stockpile d fin e sla g leachat e throug h overal l volum e reduction

. However
, th e effectivenes s an d implementabilit y o f thi s alternativ e 

### woul d b e affecte d b y the regiona l marke t deman d fo r the material

. Effort s conducte d t o identif y market s hav e bee n 

### unsuccessfu l t o date
, bu t a potentia l fo r futur e market s exist s and
, therefore
, thi s alternativ e i s propose d a s a con tingenc y wit h "N o Action " a s th e preferre d alternative

. Cos t effectivenes s i s hindere d b y th e distanc e th e sla g 

### materia l i s locate d fro m a majo r marke t an d th e cos t asso

ciate d wit h sortin g th e slag

. Cos t fo r us e o f th e fin e sla g a s aggregat e i s estimate d a s a $1,120,00 0 los s afte r resale
, whil e the cos t fo r us e a s fil l materia l i s estimate d a s a $244,625 los s afte r resale

. 

### DESCRIPTIO N O F NO-ACTIO N PREFERRE D ALTERNATIV

E Th e F S use d a comparativ e analysi s o f alternative s t o qual

itativel y evaluat e eac h alternativ e an d identif y th e advan

tages an d disadvantage s o f eac h alternativ e relativ e t o th e others
, a s wel l a s t o identif y ke y tradeoffs

. A gri d com pariso n metho d wa s use d t o ran k th e alternative s an d thei r attainmen t relativ e t o th e NC P criteria se t fort h i n th e SFS

. Alternative s wer e ranke d on a scal e o f 1 t o 5 , wit h 5 bein g t h e highes t attainmen t o f th e criterion

. Tota l score s fo r eac h alternativ e were : Alternativ e 1 : N o Actio n at 41; Alternativ e 2 : Institutiona l Control s a t 39 ; an d Alternativ e 3 : Resourc e Utilizatio n a t 36

. Selectio n o f th e N o Actio n Alternativ e wa s base d o n thes e results

. T h e N o Actio n Alternativ e leave s source s i n thei r existin g conditio n wit h no contro l o r cleanu p planne d an d i s select

e d fo r resource s tha t pos e n o ris k t o huma n healt h o r th e environment

. Th e N o Actio n Alternativ e i s preferre d wit h th e contingenc y tha t resourc e utilizatio n ma y b e undertak

e n i n th e future

. Resourc e utilizatio n involve s use o r reuse o f th e source materia l a s a commercia l produc t whic h
remove s th e sourc e partiall y o r totall y fro m th e site

. Base d o n subsla g sampling
, metal s hav e no t leache d an d wil l no t leach fro m th e stockpile d fin e sla g i n concentra

tion s tha t wil l hav e a n advers e impac t o n soils
, surfac e water , o r groundwate r i n th e area . Sla g hardness
, th e lac k


### o f acid-generatin g potential
, an d th e absenc e o f an y sig

nifican t metal s beneat h th e sla g als o indicat e that th e 

### potentia l fo r exposur e t o metal s o f concer n foun d i n th e sla g i s unlikel y t o change i n th e lon g term

. Reus e o f th e stockpile d fin e sla g woul d marginall y reduc e an y possibl e residua l ris k becaus e o f volum e reduction

.

### ACRONYMS AO C Administrativ e

Orde r o n Consen t ARARs Applicabl e o r Relevan t an d Appropriat e Requirement s CDPH E Colorad o Departmen t o f Publi c Healt h
an d Environmen t 

### CERCL A Comprehensiv e

Environmental Response

, Compensation

, an d Liabilit y 

### Ac t o f 198 0 C S M Conceptua l

Sit e Mode l D&RG W Denve r an d Ri o Grand e Wester n Railroad EP A U

. S

. Environmental Protectio n Agenc y F S Fina l

Stockpile d Fin e Sla g Feasibilit y Stud y 

### OU 3 Operabl

e Uni t 3 PR P Potentiall

y Responsibl e Part y RI Remedia l

Investigatio n RI/F S Remedia l Investigation/Feasibilit

y Stud y RO D Recor d o f Decisio n 

### N C P Nationa l

Contingenc y Pla n N P L Nationa l

Prioritie s Lis t p p m part s pe r millio n 

### SAR A Superfun d Amendment s an d Reauthorizatio n Ac t o f 198 6 S F S Site-Wid

e Screenin g Feasibilit y Stud y 

### GLOSSAR Y Actio n Level : I n th e Superfun d program , th e leve l o f contaminan t concentratio n i n th e environmen t hig h 

### 1 0 enoug h t o warran t action o r trigge r a respons e unde r CERCLA/SAR A an d th e NCP

. 

### Administrativ e Orde r o n Consen t (AOC) : A lega l agreemen t signe d b y EPA

, th e potentiall y responsibl e part y (PRP ) fo r a site , an d sometime s th e state

. Unde r a Consen t Order
, th e violato r agree s t o pa y fo r correctio n o f violations
, tak e th e require d correctiv e o r cleanu p actions , o r refrai n fro m a n activity

. I t describe s the actio n t o b e take n an d ca n b e enforce d i n court

. 

### Administrativ e Record : A fil e tha t i s maintained
, an d contain s al l informatio n used
, b y th e lea d agenc y t o mak e it s decisio n on th e selectio n o f a respons e actio n under CERCLA

. Thi s fil e i s mad e availabl e fo r publi c revie w a t on e o r mor e informatio n repositories nea r th e site

. A duplicat e fil e i s hel d i n a central location
, suc h a s a n EP A Regiona l Office

. 

### Aquifer : A n undergroun d geologica l formatio n o r grou p o f formation s containin g useabl e amount s o f groundwa

te r tha t ca n suppl y well s o r springs

. Arsenic : A grayish whit e elemen t foun d naturall y i n the environment

. I t i s a byproduc t o f copper , zinc , an d lea d smelting

. Dose s take n ove r lon g period s can caus e birt h defect s an d geneti c damag e i n tes t animals ; ther e i s evi

denc e tha t i t ca n caus e ski n an d lun g cance r i n humans

. Ballast : Grave l o r broke n stone lai d i n a railroa d be d o r use d i n makin g concrete

. 

### Baselin e Ris k Assessment : A CERCL A stud y conduct

e d a t th e sam e tim e a s th e remedia l investigatio n (an d containe d i n th e RI/F S report ) tha t determine s an d evalu



### ate s risk s tha t sit e contaminatio n pose s t o publi c healt h
an d th e environmen t i n th e absence o f remedia l action

. Comprehensiv e Environmenta l Response

, Compen

sation , an d Liabilit y Ac t (CERCLA) : A federa l la w passe d i n 198 0 an d modifie d i n 198 6 b y th e Superfun d 

### Amendment s an d Reauthorizatio n Ac t (SARA)

. I t set s u p a progra m t o identif y site s wher e hazardou s substanc e hav e been
, o r migh t be
, release d int o th e environment an d t o ensur e the y ar e cleane d up

. Conceptua l Sit e Model : A proces s in whic h informatio n abou t wast e sources, releas e mechanisms
, exposur e path

ways , an d receptor s a t o r nea r a sit e i s use d t o develo p a conceptua l understandin g o f the site , i n order t o evaluat e potentia l risk s t o huma n healt h and th e environment

.

### Consent Decree : A lega l document
, approve d and issue d b y a judge
, tha t formalize s an agreemen t reache d 

### betwee n EP A an d potentiall y responsibl e partie s (PRPs ) wher e PRP s wil l perfor m al l o r part o f a Superfun d sit e cleanup

. Th e consent decre e describe s actions tha t PRP s ar e require d t o perform

. 

### Feasibilit y Study : A CERCL A stud y whic h identifies
, 

### screens , compares , an d evaluate s differen t alternative s fo r cleanin g u p sit e contamination

. Heavy Metals : A grou p o f chemica l element s character

ize d b y thei r abilit y t o conduc t electricit y and heat

. 

### Exposur e t o som e heav y metal s ca n hav e toxi c effect s o n th e bod y an d ca n caus e advers e impact s o n fis h an d othe r aquati c communities

. Heav y metal s ca n b e highl y toxi c a t relativel y low concentrations

. Huma n Healt h Ris k Assessment : Th e portio n o f th e baselin e ris k assessment tha t addresse s potentia l risk s t o huma n receptor s a t o r nea r th e site

. 

### Institutiona l Controls : A lega l an d enforceabl e restric

tio n o r agreemen t that enhance s an d complement s th e permanenc e o f a cleanu p remedy

. Example s are laws
, and zoning , lan d use , and dee d restrictions

. Leachate : A liqui d resultin g whe n water, suc h a s stormwate r o r rainwater , collect s contaminant s a s i t trick

le s dow n throug h wastes o r contaminate d soil

. Lead : A meta l tha t i s hazardous t o health
, i f breathe d or swallowed

. It s us e i n gasoline
, paints , an d plumbin g compound s ha s bee n sharpl y curtaile d or restricte d b y federa l laws

. Childre n les s than si x year s o f ag e ar e con sidere d th e mos t susceptibl e t o lea d poisoning

. Lea d accumulate s i n the body
, and exposur e t o lo w level s o f lea d ove r lon g tim e period s ma y caus e brain
, bone
, o r nerv e damag e o r learnin g disabilitie s i n children

. 

### Nationa l Oi l an d Hazardou s Substance s Pollutio n Contingenc y Pla n (NCP) : Th e federa l regulatio n tha t guide s th e CERCLA/SAR A program

. Part s Pe r Millio n (ppm) : A uni t o f measure use d t o expres s ver y smal l concentration s o f contaminatio n i n soil
, sediments
, water , air , o r othe r media

. Propose d Plan : A document requestin g publi c inpu t o n a propose d remedia l alternative

. 

### Recor d o f Decision : A documen t whic h i s a consolidat

e d sourc e o f informatio n abou t the site , the remed y selec

tio n process , an d th e selecte d remed y fo r a cleanu p unde r CERCLA

. 

### Releas e Mechanism : The mean s b y whic h a contami

nan t ca n b e release d fro m a sourc e o f contamination

. Example s includ e spills
, soi l disturbance
, o r leachin g t o groundwater

. 

### Remedia l Investigation : A stud y conducte d t o identif y th e types , amounts , and location s o f contaminatio n a t a facility

. I t als o evaluate s possibl e ris k t o publi c healt h
an d th e environmen t fro m exposur e t o contamination

. 

### Resourc e Utilization : Th e us e o f certai n wast e materi

als
, suc h a s fin e slags
, fo r commercia l purpose s suc h a s 

### aggregat e i n concret e o r backfil l material

. Screenin g o f Alternatives : Durin g th e feasibilit y study
, 

### alternative s ar e evaluate d t o verif y that the y ar e protec

tive , mee t regulatory requirements , an d ar e imple

mentable

. Slag : Th e solid
, nonmetallic
, glasslik e byproduc t forme d i n a blas t furnac e o r smelte r whe n meltin g metal s o r reducin g ores
. Sla g float s a s a liqui d o n to p o f th e process , and afte r i t i s coole d and solidified
, ma y b e use d
a s a n aggregat e i n concret e o r fo r othe r purpose s suc h a s backfill

. Smelter : A facilit y i n whic h or e i s smelted
, tha t is , melt

e d i n orde r t o separat e ou t th e metal

. 

### Superfun d Amendment s an d Reauthorizatio n

Ac t (CERCLA) : Modification s t o CERCL A enacte d o n Octobe r 17 , 1986

. Tailings : Th e portio n o f minera l ore s tha t i s separate d
ou t durin g th e millin g o f or e an d disposed

. Transpor t Pathways : Th e mean s b y whic h contaminan t migratio n ma y occu r onc e release d fro m a source o f con tamination , fo r exampl e via windblow n dus t o r surfac e wate r runoff

.

1 1