UNITE D

STATE S ENVIRONMENTA L

PROTECTIO N

AGENC Y REGIO N VIII 9 9 9 18t h STREE T - SUIT E 50 0 DENVER , COLORAD O 80202-246 6 " " 044S3 O 

## NOV I 9 I992 Re£ : 8HWM



# - S R 

# ADMINISTRATIV

E RECOR D M s

. An n Veigal , Projec t Manage r 3-^' ^ Morriso n Knudse n Corporatio n Environmenta l Service s Grou p 710 0 Eas t Bellevie w Avenue , Suite 30 0 Englewood , Colorad o 8011 1 R E : EP A Comment s o n the.Responsivenes s

Summar y Fo r Th e Interi m Draf t Lead.an d Zin c Sla g Pil e Remedia l Investigatio n Reports , Californi a Gulc h NP L Sit e 

### Dea r Ms

. Veigal : T h e U.S

. Environmenta l

Protectio n Agenc y (EPA ) ha s reviewe d t h e Responsivenes s

Summar y fo r th e Draf t Lea d an d Zin c Sla g Pil e Remedia l Investigatio n

(RI ) Reports

. Th e comment s liste d belo w reflec t discussion s

a t th e Octobe r 30 , 1992 , monthl y meeting

. On e issu e tha t neede d t o b e addresse d wa s th e proces s fo r incorporatin g th e result s o f th e meta l speciatio n wor k int o th e variou s remedia l investigatio n

reports

. I t i s EPA' s positio n tha t ever y RI repor t tha t i s submitte d wil l serv e a s a stand

alon e document describin g the result s o f a particula r R I activity

. Therefore , th e Lea d an d Zin c R I Report s shoul d be resubmitte d as fina l document s prio r t o receip t o f meta l speciatio n results

. E P A COMMENT S ON RESPONSIVENES

S SUMMAR Y FO R INTERI M DRAF T REPORT F O R LEA D AND.ZIN C SLA G PILES : Lea d Sla g Pil e R I Repor t 1

. Respons e t o Genera l Comment No

. 2 an d Specifi c Comment No.15 ; Sinc e inclusion.o f dat a fro m othe r Sit e remedia l investigation s (i.e. , hydrogeology ,

surfac e water , residentia l soils , etc. ) i s no t withi n th e scop e o f th e sla g R I reports , the n inclusio n o f result s fro m th e meta l speciatio n repor t ar e als o considere d ou t o f thi s scope

. I t i s EPA' s understandin

g tha t th e Fina l R I repor t woul d b e distribute d prio r t o obtainin g th e meta l speciatio n results

. I n th e even t tha t th e speciatio n result s chang e conclusion s

tha t wer e derive d fro m th e R I results , a n addendu m wil l be adde d t o th e RI report

. Printed on Recycled Paper2

. Respons e t o Genera l Comment No

. 3 : I t i s unlikel y tha t th e subsla g soi l wil l b e considere d a s background

. Therefore , th e inferenc e tha t th e soil s coul d b e indicativ e o f backgroun d condition s o r tha t th e subsla g result s ma y be usefu l durin g backgroun d geochemistr

y 

### evaluatio n i s no t appropriat e fo r inclusio n i n thi s R I 

### report

. I t is'SlPA' s understandin g tha t Morrison

- Knudse n wil l coordinat e wit h th e authors o f th e Pre

- Minin g Geochemistr y

Work Pla n t o addres s this issu e further

. 3

. Respons e t o Genera l Comment No

. 7 ; Th e Stat e an d EP A remai n concerne d wit h th e proces s that wa s used t o determin e maximu m windspeed s a t th e site

. Th e Stat e mentione d a stud y tha t was conducte d a t th e Eas t Helen a Sit e tha t ha s potentia l applicatio n a t Californi a Gulch

. EP A assume s tha t CD H wil l follo w u p wit h M- K o n thi s issue

. 4

. Respons e t o Genera l Comment No

. 8 an d Specifi c Comment Nos

. 46

. 53

. an d 63; EP A accept s tha t th e column leach tes t result s ar e th e bes t estimate s availabl e an d tha t th e numbe r o f cycle s wa s predetermine d

i n the wor k plan

. However , lea d concentration s

wer e increasin g at the end o f th e column leach tests

. Therefore ,

thes e estimate s canno t arbitraril y b e considere d a s lowe r bounds

. 

### Furthermore , fo r the sam e reaso n on e canno t assum e tha t potentia l maximu m loadin g has bee n achieved , regardles s o f whethe r o r no t th e colum n leach test s hypotheticall

y overestimate d metal s leachin g fro m th e sla g unde r fiel d conditions

. ZIN C SLA G PIL E R I REPOR T 1

. Respons e t o Genera l Commen t No

. 7 ; Refe r t o Respons e N o

. 3

. above , pertainin g t o th e Lea d Sla g Report

. 2

. Respons e t o Pag e 6-4

. Summar y o f Verificatio n

o f th e Conceptua l Mode l (Responsivenes s

Summar y Page No

. 17) ; A n emissio n rat e o f 0.0 0 appear s questionable

.

Thi s equatio n shoul d be verifie d fo r appropriatenes s

an d a mor e applicabl e emissio n rat e substituted , i f on e i s found

.I

f yo u hav e an y question s regardin g thes e comments , fee l fre e t o cal l m e a t (303 ) 293-1529

. 

### Sincerely , Denis e Link Remedia l Projec t Manage r cc : Rus s Alien , CD H 

### Bil l Fieselman , Jacob s Engineerin g Nancy Mangone , EPA-OR C Kathlee n Snead , D&RG W Railroa d