-------
EPA/ROD/R05-88/080
Mason County Landfill/ MI
First Remedial Action
16. ABSTRACT (continued)
placed in the top of the landfill. The site has been separated into two operable units;
one for the landfill contents and one for the ground water. This source control
remedial action addresses the landfill contents. Contamination of the shallow and deep
aquifer will be addressed in a subsequent remedial action. Site investigations indicate
that contamination of surface water, surface sediment, soil, and offsite air quality are
not sufficient to warrant remedial action. The primary contaminants of concern
affecting the ground water are VOCs including benzene, PCE, TCE, and xylene.
The selected remedial action for this site includes: construction of a RCRA cap over
the landfill; access restrictions; deed restrictions on and near the site to prohibit
use of the shallow aquifer; and ground water monitoring. The estimated present worth
cost for this remedial action is $2,800,000, with present worth O&M costs of $1,000,000
over 30 years.
-------
RECORD OF DECISION
SELECTED INTERIM REMEDIAL ALTERNATIVE
Site Nave and Location
Mason County Landfill
Mason County, Michigan
Statement of Basis and Purpose ,
This decision document presents the selected interim remedial action for
the Mason County Landfill, in Mason County, Michigan, developed in accordance
with CERCLA, as amended by SARA, and to the extent practicable, the National
Contingency Plan. This decision is based on the administrative record for
this site. The attached index identifies the items that comprise the
administrative record upon which the selection of the remedial action is
based.
The State of Michigan has concurred with the selected remedy. The letter
of concurrence is attached to the Record of Decision package.
Description of the Selected Reaedy
The selected remedy is an operable unit that will address the landfill
contents portion of the site by properly capping the landfill. The operable
unit that will directly address the groundwater contamination and other off-
site contamination, or potential contamination, shall be addressed after more
investigation is done, including the assessment of the effectiveness of the
new landfill cap. The selected remedy is considered cost effective and is
consistent with the eventual final remedy. The specific components of the
selected remedy include:
* a RCRA subtitle C compliant soil/clay cap,
* a fence around the site,
* deed restrictions on and near the site to prohibit use of the shallow
aquifer, and
* continued monitoring to apply towards the groundwater operable unit and
to monitor the effectiveness of the new cap.
-•'*•"
Declaration
The selected remedy is protective of human health and the environment,
attains Federal and State requirements that are applicable or relevant and
appropriate to the remedial action, and is cost effective. This remedy
utilizes permanent solutions and alternative treatment technologies to the
maximum extent practicable for this site. Because treatment of the principal
threats of the site was not found to be practicable, this remedy does not
satisfy the statutory preference for treatment as a principal element of the
remedy.
-------
-2-
*hn ^Uh'hl. JTV1'11 PeSUlt ln*azardous substances remaining on-site
above health-based levels, a review will be conducted within five years after
commencement of remedial action to ensure that the remedy continues to provide
adequate protection of human health and the environment. yruviae
Date
Valdas V."
Regional Administrator
-------
Page No.
r
TITLE
AUTHOR
MASON COUNTY, MICHIGAN
DATE PAGES
Apoendix A Kason County Landfill
Statement of Horn
For Conducting RI/FS
Letter to Ethel Lister, Clerk
Pere Ha&ei'YoSnship, re lab
analysis of waste confining
it is industrial waste.
Letter to Arthur L. Sheman
answering questions on
"lason County Landfill
To Mason Cty Dept Punhc
Uorxs: Concludes Phase I
of landfill program and
includes reconendations
for Phase II and a segment
of Phase III work
Ann Sause, Ecology i
Enviromient, Inc.
Letter encloses sew re ouolic
cowaient on landfill
Prein i Newnaf
00/00/00 16
75/11/26
Bureau of Envrrwtal Protection 76/11/OS
Uilhai i Works
81/10/06 83
FWxrttshalk, Dcot Ntrl Resrs 82/05/13 2
Potential Hazardous waste Site EPA
Site Inspection Report
Deposition of Tisotny 0. Hansen
State of Michigan Deposition
of Dennis 3. Forrest
Deposition of Sooert Dixon
.lison County Iris rtoad Landfill Aquatic Systems, Ire.
vreoarea for: Noraiuna DunJap
I Associates
Letter to Acne Disposal Company 'JSEPA Peg V
Final Ccffliounity Relations PUn CKL1 HILL
«to RUnippo - USEPA re:
1 Ojunty Landfill
ft I Existing Data Analysis
Task EO
SMcBee - 0&1 HILL
82/06/23 £8
82/06/23 75
83/06/2:3 ^
85/07/25 26
85/08/05 6
86/04/00 35
86/04/18 52
-------
Pagt No. 2
01/22/88
»ASON COUNTY, filCHIGflN
TITLE AUTHOR OflTE PAGES
Work Plan 8I/FS CH2K HILL 86/06/27 78
fltt IV Zone I! QflPP * CKffl HILL 87/05/21 399
Work Plan Pnase II ft I/PS Q& HILL 87/06/00 38
OfiflFT: Pnase I RI Ofi« HILL 87/06/05 268
Tecmucal Report
-------
Pagt No.
/22/Bfi
TITLE
AUTHOR
MASON COUNTY, MICHIGAN
GUIDANCE DOCUMENTS - NOT COPIED
MY BE REVIEW) AT EPA
IN CHICAGO, IL
OATE
Standard Operating Safety Guide
Manual
Outdance on Remedial Investigations
under
Delegation of Remedy Selection
to Regions
Guidance on Feasibility Studies
Under CEfiOA
Superfund Public Health
Evaluation Manual
flOU Between tne fiTSDR and EPA
>ns Guidhnes and Ssecs for
.q QAPPs (QAMS-005/80)
'Jsers Guide to tne U5£PA Contract
laooratsry Prograa
80/12/W
82/Ofl/OO
Intern Standard Owrating safety
Guides
Sjcerfuro C
Selations
82/M/OO
83/05/12
Cc-munity relations in superfuno:
Ccinunity Relations in Superfurio:
A Kandoo>;k
buidarce "leooranduti on Use and
Issuance c-f Administrative Orders
Section 106 of CE.RCLS
Interia CtSC^A Sett lament Policy
Cotohance aitn otner
Statutes
8J/09/00
SS/W/w
83/03/08
84/00/00
85/02/12
-------
iC9 NO.
hftHt PHGES WTE
TITLE
HbMINISTMTlVE RECORD INDEX-UPDflTE
flftSGN COUNTY UWDFILL
-MflSON COUNTY,
HUTHGR
RECIPIENT
DOCUMENT TYPE
6 85/08/05
£ 65/08/20
£ 85/08/22
Sepuest to PRP that tney Kerry Weiss - USEPfl
Voluntarily undertake actions
necessary to aoate or orevent
the release of hazardous
suostances.
ficse Disposal Co. Corresponaence
Response to 6/5/85 Notice
Letter.
J.KoiDa-atty.for EdiChristine Dams Jonn Oaks-USEPA Corresoonaence
Response to UStPA letter of Clay Olasteao-flason Co.
8/5/B5
and an oojection to being
considered a PRP in tnis
natter.
John OaKS-USEPfl Corresponoence
1 85/06/23 Letter reouesting a response Frank Hollins-uSEPfl
to
a letter sent 8/5/65
requesting
that tne PRP participate in an
RI/FS.
Harm son-Walker Correspondence
Refractor
1 85/08/23
1 S5/08/25
1 85/08/26
1 35/06/28
1 65/08/29
Request that the PftP respond Frank Rollins-OSEPfl
to letter of 8/5/85 requetsing
that tney participate in
an RI/FS.
letter reauesting a response FranK Rol1ins-uSEPP
to
tne USEPfl- letter of 8/5/65
whicn requested a response
en their willingness to
conduct or participate
in an RI/FS.
Letter declining to
participate
in an ki/FS.
J.Ko:ca-atty. for Ed Dams
Invitation to attend a nesting FranK fiolhns-USEPH
to oee held on '3/6/85.
Invitation to PRP to
participate
in a neetmg to ce held on
frank Rollms-USEPfl
The County of
nason,MI. •
Corresponaence
ficue Disposal Co. Corresponoence
Frank Rol1ins-USEWl Corresponaence
Clay Olrasteaa-.iason CorrespC'noence
Co.
L.Denooyer-Harbison Correspondence
Walker
1!6 65/09/06 Response to Information
Refractories
FranK
-uStf'H C.orre?conoence
-------
no.
t PAGES GATE
I 65/12/04
TITLE
Request..
HiMNlSTftATIvt RECORD IMtX-uPDATE
BASON COUNTY LANDFILL
DHoON COUNTY, MICHIGAN
AUTHOR
RECIPIENT
DGCUi€NT TYPE
Pi
-------
Page No. i
to
E144S; E1624 to E 1447.
6c!/G7/l9 FtevieM and data package for Cnuck Eil
EPA data set no. 5F1658,
i«0 traffic noi tlbio.
eo/ii/lfi review ano oata package for ^atricx Cnuriila-uSEPA
h'PA data set no. SF3579,
SMO traffic no. E01-E015.
86/12/22 Review and data package of Jay Thakker-USEPA
EPA data set no. SF3595
SSO tarffic no. E0l-£0lc'
B.Bartholoaew-Eeol Sampling/Data
4 Env.
boo Saeipiing/Data
BartnolmetHicoi. 4En
v.
B.Bartnolonetrtcol. Saapling/Data
tEnv.
Chc'M Hill
CH2J1 Hill
Baapling/Data
Sampling/Data
67/01/05 Review and data package of Jay 1 nakker-USEPfi
EPA data set no. 5F3534
5«0 Traffic no. r£C7il-739;
fOaS'S-SlO; «EC234-i40;
BEB369-268.
87/01/05 Review and data package: USEPA Patrick. Qvjrilla-USEPA
data set no. SF3S94 , SMO
Traffic
no.
b6/0l/il Review ano oata package for Curtis *oss-u£EPH
tFfi data set no. SF4/45:
i^O traffic no. "itc>
-------
Page No.
O'i/i'9/da
nT< •'
;~t
SflO traffic no. I1E6673,680,
695,697-700, 793,794.997,;
1*1661,796.800;MEK302,322-327,
412,413.42S-434,442-445,464;«£
F3%.
HDPIIN1S1 NATIVE SECflfiD SABPLING/DATA INDEX
MftSON COUNTY LHNOFILL, HflSON COUNTY NlCHISfiN
DOCUMENTS NOT COPIED, HftY BE REVIEWED AT THE
USEPfl KE6ION V OFFICES, CHICAGO, ILLINOIS.
RECIPIENT
DOCUMENT TYPE
•.'8/02/12 Review e>.no oata package for
EM oata set no. SF4739:
S«0 traffic no. EK161-175.
Review ana oata package of
EPA data set no.SF4740:
SMO traffic no. EJc'6c:-£63;
ER076-82, 084-086, EL198, £00,
457,458,441,569,571,579.
86/02/25 Review ano oata package for
EPi^ cata set no. SF47!444-446, 443,501.
r>c c.'.ts pgc-Kfge or
kC'A cata 9=: ro. ic4/4/:
S.r-0 traffic no. £3i-ttl,
Jay ThakKer-uScKfi
v'5:ricv. C'nun]io-'.'Sc^'ft
CHclK Sanpl ing/Data
HilliB.Wuppo-USEPfl
CH2B iaraoiinq/l'ata
hilliB.Hnippo-USEPrt
-------
Page to.
03/19/88
UHl'E
TITLE
E53-fc73.
dtf/04/05 Review ana data package of
EPA data sec no. SF<»746:
3KO traffic no. a£K465-47l;
KEH444-«46, 443,501.
d6/04/06 Feviei* and data package of
EPfl oata set no. 3FW10:
SnO traffic no. ullegioie;.
MD«INISTKftTIVt' RECORD SfWPLlNS/DATfl INDEX
MASON COUNTY LANDFILL, MSCN COUNTY WICHIGftN
DOCUWBffS NOT COPIED, NftY BE REVIEWED ftT THE
USEPfl RESIGN V OFFICES, CHICfiGO, ILLINOIS.
RECIPIENT
Win
Jay ;haKker-USt>'A
Uinston Vijjeswarapu-OSEPfl
TYf€
Saapling/Data
HilltB.Wiiooo-USEPfl
CD,1 i Dan
Cozza-USEPfl
SaHDling/Data
-------
Page NO.
WON COUNTY LANDFILL, HHSClN COUNTY, MICHIGAN
GUIDANCE OUCUWENTS - NOT COPIED
KftY Be REVIEWED AT USEPA RESIGN V,
CMCfltf), ILLINOIS
TITLE
AUTHOR
DATE
Stanaaro Operating Safety 6uioe
Manual
buicance on Ke«eo:ai investigations
Unoer CS
Delegation of ftewefly Selection
to regions
Suicance on heasiOiiity Studies
Uncer LE^.LLrt
Puohc Healtn
n .lanuai
Cij between tne HTSDff ano tP
Inter IK ouiahnes and Soecs for
oaring Qrt
Upe
Guice to tne UsEPA Contract
Laooratory Program
80/12/29
82/06/00
interrd itancard Ooerating Safety
Guices
82/09/00
Superfuno Coonunity Relations WHednan
Poiicy
Corivunity Kelations in Superfunc:
nanooooK
83/05/12
83/09/00
CouBunity delations in Suoerfuna:
A
83/09/00
xre r?j»randun en U5« aro
issuance of icaimstrav.ve Orcers
uncsr section lOb of C£,-(Cl>)
83/09/06
Interin CcSCLft Settie;ient Policy
Ccl-CLri CoMoharice witn otner
Statutes
84/00/00
85/02/12
-------
Page No.
PhGtS DM it TlftJ:
t Xtt.UKb lUlrt-X UPl/Hlt NU. i
LiN LUUfHr LWJUf'ILL
HU'fWJH
Kk'CIPiENf
OOCifltNT TYPE
-H
Corp.
walker Janet riaff - UctPH
Merract.
fson, area resicent Crcce, Usci-vi
neiiey for baae, bit>'H
forquette funsnip. bd.
Joiies J. r.ooza
, UStPri
Molhngs-DatPfl
na£cri, area resiac-nt
Corresponaerce
Ccrresporidence
Corresporidence
Correspondence
Correspondencll
Corresponoerice
Correspc>noerce
5 Bb/Os/iS Letter cobueiiting en draft Pacific, us L'ept. of Interior Coz:a, Use
J efi/Ou/20 Letter cc-aatnt i ng on tPH's Treup, atty. fcr
HOD
Lty. uc-!:a 6 h'aaell, uitPfl
Letter rei-p-jnaing to Pnv Oavi;, btty. for P«P itr«its Crcce, uitPfl
rvitice letter afa couucnting Steel
on tne hl/r-S and tne
Action Plan
Oa/il Letter cc-Kuc-nting on Hl/rs bunlao, HC-SI snore tngtneenng Cozza,
and PropoEeo Pi in.
-: LOKerria ino c-:«.*iii£ oy uar/
tna itite of tticnigin ar,o
a request tnit tf(*y rt;
incluaej u, tr.e fir.ii hiiu
Cc'rresponderice
Correspondence
Corres(>jndence
Correspondence
Miry tiioe - ostPH Lorre&poroerice
-------
' KtCOM I (MX Ut-iHil NO.
BliatJN COUNTY LHiNllt-'lLL
MlLMibHN
FICHt/Fhhft:
TlTLt
along HI in coromK>nal
acceptance of tne lira ft ft
da recievea on u/T//tto.
Coriditional afcceptence of
tne Proposed Plan for
j 68/0'i/cO tetter aaore&sing corcerns
in the Hub a/Kj inoicates
riOM tnose cc-riceiYiS nave
been or will oe addressed.
4 twi/ua/00 Fact Sneet :
Mason Dvjnty Lanjfill
(•fcasiDihty biudy Ccaoleteo
Mitn information re:
tiue uA place of 6-1 /-fto
pijohc
til 11
Mary bace - USti-'H
ban Cozza -
bary Suentner-UbfiPA
b'J 68/06/1 / Transcript of o-l't-tio
puolic ueetinq
NcLoutn, lertified Electronic
uper.
cl 68/04/06 Letter responuintj to request Herceg,
for State Hppiicacle or
helevant arid Appropriate
Cozza, Ubtf'ft
to tne fliiuri County site,
ucludir.g Hhtins ineritionea
t)7/liivOO Draft Ucnri.:a Hlternatives Dev
Vecnnical Keuoranouu
66/0'//li Final HI Report
8a/0a/0t u&Pfl's Pr-oposeo Plan
for rtaton Lty. sue
Hill
UStPA
a/i'O/Mj f-uolic Courient Report
on tne r'eoiioility Stuay
riepOl't
iruli
USLt-'H
DOCU«£NT TYPE
Correspondence
Correspondence
Fact Sheet
Meeting Notes
Other
Reports/Studies
Reports/Studies
Reports/Studies
Reports/Studies
-------
CF IMSRIM REtCnCAL MaEEtMTVE SELECTION
mscw cousny
OXJNIY,
, 1988
-------
TABLE: CF CCNTENTS
page
I. xi'iyi LCCAT1CW AND OESCRXFTKXT ........................... . ...... 1'
H. SITE: BACKGROUND AND ENfclULMfJM1 ACTIVITIES ..................... 2-10
A. Site History ............................................... 2
B. Past Studies ............................................... 3
C. current Site Status ........................................ 3
D. Site Characteristics ....................................... 4-9
E. Summary of Site Characteristics ............................ 9^-10
F. CERCLA Enforcement ......................................... 10
IH. OMUNITY RECAHCTE ............................................ 10
IV. SCOPE CF FEftSTBTLTTT STUDY ..................... f ............... 11
v. SITE: RISK AssEsaiENr' SIMWOT ............. . .................... . 12-13
VI. DESOKIPEICN" CF REMEDIAL AUERKMIVES ........................... 14-28
A. Screening of Alternatives .................................. 14-21
B. Alternatives Considered. ................................... . 21-28
VTII. SIMRRY CF CCME5VRATTVE MM3SIS CF AUEERWO1TVES ................ 28-29
IX. PRTOSED FLAN AM) DOOJMENTftElCN GF SIOSEFICANr CHMX25 (Section
117 (b) [[[ 29
X. *«'3J«t?l'Hl REMEY AND SIMUTCBT TEEEPKUKTICKS ................... 30-34
A. Landfill Contents Cperable Unit ............................ 30-33
B. Garoundwater Cperable Unit .................................. 33-34
XI. SOME ISSUES .................. ................................. 34
XII. SIMftRY [[[ 34-35
ATEPOMENTS
-------
OF TNITRIM REMEBVL ACEEBNftTIVE SELECTION
COUNT? I2BDETLL
COUNTY,
I. SITE LOOVHON" AMD EESCKEFnCKr
•Die Mason County Landfill Site is located three miles south of the City of
Ludington and one mile east of Lake Michigan (see Figures 1 and 2). One
Site occupies approximately eighteen, acres of a predominantly rural area in.
Fere Marquette Township; approximately ten acres of the Site is landfilled.
Ludington, Michigan has a population of about 9,500. The population of
Mason County was estimated at 26,400 based on the 1980 census. "Die
population within a three mile radius of the Site was estimated at 1,112.
As Figure 3 indicates, just north of the Site is heavily wooded and orchards
are located to the east and south of the Site. The local topography varies
fromi relatively level upland, areas south and east of the landfill to steep
valleys north of the landfill. Figure 3 shows both the current topography
and. Site topography before landfilling began in 1971. Comparison of the
topographic contours indicates that an. estimated 140,000 cubic yards (+/-
20,000 cubic yards) of fill is buried in the landfill. The landfill is
generally a valley fill with a maximum depth estimated to be 40 to 50 feet.
Surface waters in the Site area are Iris Creek, the Fere Marquette River,
Fere Marquette Lake, and Lake Michigan (see Figure 2). The headwaters of
Iris Creek are located less than 500 feet from the landfill and consist of a
wet, marshy area southwest of Babbin Road (see Figure 3). Water from, the
marshy area drains into Babbin Pond, which discharges directly into Iris
Creek. Iris Creek discharges into Fere Marquette River, which discharges
into Lake Michigan. A pumped-storage power reservoir operated by Consumers
Power Company is located approximately one half mile south of the Site.
Lake Michigan is the main drinking water source in the area and is the City
of Ludington's water supply. In rural Fere Marquette Township, residents
generally depend on small domestic wells screened in sand and gravel
aquifers for potable water supplies. There are fourteen residential wells
within about a half mile radius of the landfill that vary in depth from 30.
to 150 feet below ground surface (bgs). They are monitored biannually by
the Mason County Department of Public Health for a range of organic
parameters.
Other water uses in the area include large capacity wells that produce salt
brine for industrial use. A salt brine well about 1,000 feet west of the
landfill is screened in an aquifer at a depth of 450 feet bgs. The brine
aquifer is separated from the overlying aquifers used for potable water by
more than 300 feet of low permeability glacial till.
Mason County is underlain by bedrock formations at depths from 300 to 700
feet. Mississippi Age Coldwater Shale lies beneath the landfill Site at a
depth of 650 feet. The formation is predominantly shale with occasional
interbeds of sandstone and limestone.
-------
TOWNSHIP
•OUNOAftlES
LAKE MICHIGAN
MASON COUNTY
LANDFILL SITE
PERE MAROUrrTE
TOWNSHIP
KEY TO COUNTIES
MASON
COUNTY
BOUNDARY-
SCALE IN MILES
FIGURE 1
LOCATION MAP
MASON COUNTY LANDFILL Rl/FS
-------
PERE MAROUETTE RIVER
T-j^^ MASON COUNTY
LANDFILL SITE
SOURCE: U.S.G.S 7.5' TOPOGRAPHIC MAP
OF LUOINGTON. MICHIGAN QUADRANGLE.
FIGURE 2
VICINITY MAP
MASON COUNTY LANDFILL RI/FS
-------
MARSHY AHEA
(HEADWATERS OF
IRIS CREEK)
LEGEND
.71*
1986 GROUND SURFACE CONTOURS
ORIGINAL GROUND SURFACE CONTOURS
(1971 TOPOGRAPHIC MAP PROVIDED
FOR ACME DISPOSAL)
CONTOUR INTERVAL-25 FEET
LANDFILL (APPROXIMATE)
* — ' — PROPERTY LINE (APPROXIMATE)
NOTE: Approx.mate landfill and property boundaries based on Mason County
DPW legal property description and aerial photograph.
SCALE IN FEET
FIGURE 3
SITE MAP WITH ORIGINAL
SITE TOPOGRAPHY
MASON COUNTY LANDFILL FS
-------
Three or four subsurface tills have been recognized in the immediate Site
vicinity- The upper three tills are relatively thin and. are separated by
thick outwash deposits. A conceptual model of the regional geology near the
Mason. county Landfill is depicted in Figure 4.
u. SITE. HisTdor AND ENFORCEMENT
A. Site History
The Site property was originally owned by Edward Dains when it was selected
for use as a sanitary landfill by the Mason County Department of Public
Works (DPW). In 1971, Mason County DPW leased, the property from Mr. Dains
and subsequently entered into an agreement with Acme Disposal to operate the
landfill. Mr. Dains was hired by Acme Disposal as a Sanitation Engineer to
oversee the daily operations of the landfill from 1972 until 1978. The
Michigan Department of Public Health (MDPH) approved Acme's Solid Waste
Disposal Area license in 1971 with the stipulations that no refuse be
disposed of below the 710 foot elevation mean sea level (msl) , that the
final cover contain at least twenty percent clay, and that monitoring wells
be installed. The original Site topography is shown in Figure 3. In 1973,
landfill licensing and oversite were transferred from the MDPH to the
Michigan Department of Natural Resources (MCNR). The MDNR documented that
the slurry and. sludge wastes from local industries were being dumped at the
landfill, allowed to dry, and then covered. The Site's license was renewed
annually through 1977; it was closed in August 1978 when it reached
capacity. Public concerns over the water quality in nearby Iris Creek
prompted the Mason County DPW and the MDNR to review closure activities.
In 1981, two property owners filed suit against Mason County. One, a
neighbor, alleged that the landfill run off had. damaged property and
deteriorated the groundwater quality, while the other, the owner of the
landfill property, alleged there had been a breach of contract regarding the
property lease agreement with the Mason County DPW. As part of the
settlement with both parties, Mason County purchased, both properties and is
currently the owner of the landfill property.
In 1983, the Mason County DPW received a grant from the state of Michigan
for iirprovements to the landfill. A clay cap was completed and berms and
storm drains were constructed to improve Site drainage (Figure 5). Two
surface aerators were installed in Babbin Pond to help aerate the pond and
facilitate biodegradation of organic matter. Fifteen gas vents were placed
into the top of the landfill.
B» Past
Site studies and investigations, previous' to the formal U.S. EPA Remedial
Investigations at the Mason County Landfill, began in 1971 with a
preliminary evaluation of the landfill Site and have continued through the
Site closure work completed by the Mason County DPW in 1984-85. A
chronological summary of the major landfill investigations is provided in
Table 1.
-------
TABLE 1 (Page 1 of 2)
Summary of Previous Site Investigations
«l ton at tludy
Inllljl III* Slu4l«*
nlf<>IM«l •
IW«lih (urn)
tttr* Ck|tcll»tt
Itll Oi«i*cltrli* tilt t*ll
MI**||*| Itn4llll til*
Cpnclutloiit
«•» »»• ««Ml4 k* MM* tt Ml _
ItMUII Itcllllf «lik lUlltlliw*
V.ij
IUH *•»!• 4*ll*(l*«
Sail k*«li>|t (u**Ult4 Mtl*f t*|*r*
kit haul *ir*ll|iipMc
*• KM 1 1*1 U|
N»tm Cuunir DfN t
U.II S«»plln« ai>4
«llk I(M M«I llw UMIIII
Mil Ml«r vllk
••« l«lf«ckl«i««lk*M c«w«nl(*lleii*
•Ilk
U.S.
C*oi«chnl«l
i Ion lot It
MMOM Couiilr Orw Hanliorlni
IIM
!• fa»r wilt lntl«IU4
r fl«M
I* Ik* Mr Ik U Ik*
•411II »f»»
U*ll |fowl1*1 tM* tit I 4*1*11*
I Mlk«4* Mtt4 414 Ml
NUM|tn Ml MluM kilnt
nUhl|«A DNI lilt Crttk tutlM
1*11
Hit
HOOK Count r DfU lt»ln> •!
Ml«lil|«n !*••§ Id* Cictk
Sull*C« U*l |M<|||| CMIMI* •!• k*l««
•wf!•• Iroa IfU Citct
Cflilc*! >**<4 lntl*lll*|
•Mlllo«tl WMillorlM Mil* ktlMt*
Ik* IM4IIII *n4 Irl* Crttk
O»lr y'••<*•• UfaratllMj *l an*
M|*I !• in* IM4HII
fc piUrlly Mllultnl* «i*ljti*4
•l< Hal CMftr* «urt*c* »«i*r *n
•14 ••! tiitafl I* cktrtcitrlt*
l**ck«i* lio* ill* l*ii*l|l|
Ha •*• lltU 4
-------
TABLE 1 (Page 2 of 2)
Summary of Previous Site Investigations
(••I*
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k« I«i4ll
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414
(l*»lU| »llan« nul
tuntf to*»i»4 » ttlf
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|roun*>«lir lla« In
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Utmlly •Ullaci «n
U.I. ir* fUI4 U>**ll|*llM Hit
I«M (fit) III* •M«*M«al
Courtly Sll* tl»4U*
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CLI1*1/11
-------
DOMESTIC
WELLS
EAST
CO
5
CO
Z
Ul
_l
01
ui
x
o
oc
o.
a.
BRINE PRODUCTION WELLS
MASON COUNTY
LANDFILL
• ! . UPPER AQ
'SILTS AND CLAYS
(LOCALLY RTF* HREO TO AS TILLF
LOWER AQUIFER
LAKE MICHIGAN
. . .GLACIAL OUTWASH
AND LACUSTRINE DEPOSITS* .
GLACIAL TILL
GLACIAL OUTWASH
200-
0-1
BEDROCK AND BRINE AQUIFERS
-NOT TO SCALE-
FIGURE 4
CONCEPTUAL GEOLOGY
AT MASON COUNTY LANDFILL
MASON COUNTY I ANOFII I FS
-------
As indicated in Table 1, the EPA. Field Investigation Team. (FIT) inspected
the landfill Site in May 1982, sampling and analyzing the existing
monitoring wells. After the FIT data was evaluated, the Site was assigned a
hazard ranking system, score of 34.18, a score high enough to qualify it for
inclusion on the National Priority List (NFL,). This score was given because
of the presence in groundwater of ethyl-benzene, pentachlorophenol,
trichloroethene, 1,2 trans-dichloroethene, and 1,1-dichloroethene and the
associated toxicity and persistence of these compounds. The Site was put on
the final NFL in 1982.
The MOPH replaced S. Dains's and May's residential wells (see Figure 5) in
September 1987 because of health, risks identified by MQPH sampling done in
the fall of 1986. S. Dains's old well, approximately 400 feet from the
landfill and screened at a depth, of 130 feet, was replaced by a well 348
feet deep. The well was replaced because of the presence of 2-butanone and
4-inethyl-2-pentanane. May's old well, located approximately 1,200 feet
north of the landfill and screened at a depth, of 60 feet, was replaced by a
well 218 feet deep. The old May well was replaced because of the presence
of trace concentrations of tetrachloroethene.
C. Current Site Status
A Remedial Investigation (RI) at the Site was conducted by the U.S. EPA.
through the use of its contractor, OEMHill. The RI consisted of two phases
or sampling events. Phase I of the- RI fieldwork was conducted fromi
September to November 1986 and Phase II was conducted between October 1987
and January 1988.
The RI at the Site included the following:
1. Review^ and evaluation of past investigations as well as historical
practices and other records relating to the Site. (RI Phase I)
2. Extensive aquifer sampling and water level measurements (in both the
upper and lower aquifers) to determine groundwater quality, flow directions
and gradients, etc. (RI Phase I and II)
3. An electromagnetic geophysical survey was conducted to evaluate
whether existing landfill monitoring wells were properly positioned to
interpret potential plumes originating from, the Site. (RI Phase I)
4. Samples were collected within the wetland, Babbin Pond, and Iris
Creek to define the Site's impact on the surface waters and sediment. The
base flow in Iris creek was determined to help estimate groundwater
discharge rates into the creek. (RI Phase I and II)
5. Soil borings and the gamma logging of existing monitoring wells was
conducted to help define the geology of the Site. (RI Phase I and II)
6. The Site's gas vents and ambient air was sampled to determine the
Site's impact on air quality. (RI Phase I and II)
-------
LOWER GRATED
ANHOLE
SLOPE
IMPROVEMENT
LEGEND
GROUND CONTOUR
APPROXIMATE LANDFILL BOUNDARY
"" '- SURFA« WATER .NTERCEPT.ON BERM
*"~* BURIE° 10" PLASTIC DRAIN PIPE WITH INLET AND OUTLET
L* -»0-> -* BURIED 24" DRAIN P(PE WITH TWO MANHOLES
•»"•»»*«» DRAINAGE SWALE
CLAY CAP
SCALE IN FEET
FIGURE 5
SITE IMPROVEMENTS
OF 1983 AND 1987
MASON COUNTY LANDFILL F
-------
7. Surface soil samples were taken to determine if erosion along the
northern side of the Site presents a pathway of contaminant migration. (RI
Biase II)
8. Sanples from a drainage pipe leading from the Site to Iris Creek
were taken to determine if ground water and/or leachate is infiltrating into
the pipe and therefore presenting a possible pathway of contaminant
migration. (RI Phase I and. II)
The results of the RI are detailed in the RI Report (July 1988). The Site
FS was completed in July 1988. The FS documents in detail the development
and. evaluation of an array of remedial action alternatives for the Mason
County Landfill Site. A summary of the physical and chemical
characteristics of the Site are discussed below.
• D1. Site Qy*rflgt-reristics
1. Physical Characteristics
a. Groundwater and Surface Water Conditions
The interpretation and discussion of groundwater and surface water
conditions at the Site is based primarily upon data obtained during the
remedial investigation. Site hydrology is described in detail in the RI
report.
Groundwater - Two aquifers have been identified at the Site. The
potentibmetric surfaces of the upper and lower aquifers were determined
using water level measurements taken in December 1987 (Figures 6 and 7).
The hydraulic gradients and hydraulic conductivities of each aquifer are
summarized as follows:
Hydraulic Conductivity (cm/s) Hydraulic-Gradient (ft/ft)
Range Logarithmic Range Arithmetic
Average Average
Upper Aquifer 5.0 x 10~4 to 2.5 x 10"3 0.040 to 0.064 0.052
8.7 x 10-3
Lower Aquifer 6.1 x 10~3 to 4.4 x 10~3 0.018 to 0.310 0.025
2.4 x 10-2
The upper aquifer is unconfined and possibly perched above the subsurface
till units as evidenced by large head differentials between the two
aquifers. The till units are thin and possibly discontinuous'on the north
side of the landfill. The outwash deposits overlying the till units have
interlayered seams of silt and/or clay. The tills and. clay/silt seams
retard groundwater flow from the upper aquifer to the lower aquifer. This
subsurface condition combined with recharge (including potential recharge
from the nearby pump-storage reservoir) could produce perched conditions.
-------
;/ X / I
" / / /
'///73V
'';//;/+ -
LEGEND
684.4
GROUND CONTOUR
WATER LEVEL RECORDED IN DECEMBER. 1987
INTERPRETED GROUNOWATER CONTOUR
INFERRED GROUNDWATER CONTOUR
BORINGS WHERE SHALLOW AQUIFER WAS
NOT ENCOUNTERED IN NOVEMBER 1987.
FIGURE 6
UPPER AQUIFER
POTENTIOMETRIC SURFACE
-------
LEGEND
.-»—* GROUND CONTOUR
• 619.4 WATER LEVEL RECORDED IN DECEMBER. 1987
620 — INTERPRETED GROUNDWATER CONTOUR
, _ 630 _ INFERRED GROUNOWATER CONTOUR
SCALE IN FEET
FIGURE 7
LOWER AQUIFER
POTENTIOMETRIC SURFACE
MASON COUNTY LANDFILL Rl/FS
-------
Water fron the upper aquifer percolates downward to recharge the lower
aquifer. Downward percolation is controlled by the thickness and
permeability of the intervening till units and clay/silt seams. There may
be areas where the intervening layers are missing, which would allow a
larger quantity of water to percolate downward to the lower aquifer.
Groundwater in the upper aquifer flows generally to the northwest and
discharges into the wetlands, Babbin Pond and Iris Creek (see Figure 6).
la the lower aquifer both confined and unconfined conditions exist. The
potentiometric surface in the lower aquifer is higher than the till unit
along Inman Goad, indicating a confined condition. East and south of the-
landfill, a 20 to 40-foot thick: unsaturated zone of sand lies between the
water surface in the lower aquifer and. the till unit, indicating an
unconfined condition.
Groundwater flow in the lower aquifer trends toward the northwest (see-
Figure 7) and eventually discharges to the Pere Marquette Lake and River and
Lake Michigan. According to well logs from local brine wells owned and
operated by Dow Chemical, the aquifer is underlain by a massive till unit
(see Figure 4). The exact thickness of the lower aquifer at the Mason.
County Landfill Site is unknown.
Surface Water - The Site lies within the Pere Marquette River watershed.
Surface water units near the Site include a wetland area at the base of the
landfill that discharges to man-made Babbin Pond, which in turn discharges
to Iris Creek. Since no upslope stream feeds the wetland area, the wetland
area forms the headwaters of Iris Creek.
Iris Creek, flows for about one mile through a series of small ponds and
eventually discharges to the Pere Marquette River just west of Highway 31
(see Figure 2).
A 24-inch storm drain carrying surface runoff from the landfill cap
discharges directly into Iris Creek. Other surface runoff from the landfill
is channeled to the north through gullies that lie on the side slopes of the
landfill (see Figure 5).
The wetland area is a local discharge "area for groundwater that covers
approximately 0.8 acre. Babbin Pond covers approximately 0.1 acre and
contains about 200,000 gallons of water. The storm, drain flow is probably
intercepted groundwater because 1) the drain discharged water during several
Site visits but no surface water was observed to be entering through grated
inlets, 2) the drain pipe is buried below the water table based on a
comparison of the manhole invert elevation to groundwater elevations in
nearby wells fW7 and MC8S (See Figure 5) and, 3) the chemical
characteristics of water in the drain are similar to those in nearby
monitoring wells.
b. Groundwater/Surface Water Interaction
The surface waters are located topographically and hydraulically
downgradient of the landfill. Surface runoff from the landfill area and
-------
groundwater from the upper aquifer discharge to the wetland area. Based on
the discharge from Babbin Pond, surface water in the wetland area appears to
be gaining about' 46 gpn from groundwater. The contained, water from Babbin
Pond and the 24-inch, storm drain feeds Iris Creek at a rate of about 48 gpm.
•Die flow volume of 16 gpn. in Iris Creek indicates that surface water is
apparently lost to groundwater at a rate of about 32 gpm. One surface water
measurements indicate that Iris Creek may be a flow-through, creek (i.e.,
both gaining and losing water).
2. Chemical Characteristics
The following discussion briefly summarizes the nature and extent of
contamination according to the respective media sampled during the two
phases of the RE. Table 2 indicates the contaminants found throughout all
media at the Mason County Landfill.
a. Groundwater
The upper aquifer - Thirteen monitoring wells and four residential wells are
screened in the upper aquifer. Fourteen volatile organic compounds (VOCs)
and. ten semi-volatile organic compounds (SVOCs) were detected in the five
downgradient monitoring wells within 400 feet of the landfill.
In general, the target compound, list (TCL) or priority pollutant compounds
that can be attributed to the landfill were predominantly VDCs. Six:
chlorinated, volatile hydrocarbons were detected in at least one phase of the
remedial investigation at concentrations ranging from 1 to 59 ppb. The
highest concentration (59 ppb of 1,1-dichloroethene) was detected at M
-------
Table 2 (Page l of 2)
CHEMICALS DETECTED AT THE MASON COUNTY LANDFILL
Groundvater
Chemical
VOLATILE ORCAKIC COMPOPNPS
Acetone
Benzene
2-Butaaone
Carbon Dliulfide
Carbon Tetrachlorlde
Chlorobenzene
Ch 1 or oe thane
Chloroform
Chlorome thane
2-Chloroethyl vinyl ether
1,1-Olchloroeehane
1, 2-Dichloroe thane
1,1-Dlchloroethene
1,2-Dtchloroethene
1 , 2-Dtcnl oropropane
Tr*n«-l,2-Dichloroethene
Ethylbenzene
2-Hexanone
A-Mecftyl-2-Pentanone
Keehylene Chloride
Scyrene
Tetracnloroethene
1,1,2,2-Tetrachloroethane
1,2, &-Tr ichl orobenzene
Toluene
1,1,1-Trichloroethene
Trichloroechene
Vinyl Chloride
Xylenes
BASE/NEQTRAL
Monitoring
Wells
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Residential
Wells
Surface
Water
Sediment
X
X*
X*
X*
X*
X
X
X
X
X
X
X
Cat
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
Surface
Soil
Polycycltc Aromatic Hydrocarbons
Acenaphchene
Acenaphchylene
Anthracene
Benzo(a)anthracene
Benzo(a)pyrene
Benzo(b) f luoranthene
Benzo(k)fluoranthene
Bis-(2>Oiloroisopropyl)ether
2-O> loronaphtha 1 ene
fc-Chlorophenyl*phenylether
Chrysene
Oibenzofuran
Fluoranthene
Fluor ene
2*Methyl Naphthalene
Naphthalene
Phenanthrene
Pyrene
N-Nitrosodiphenylaaine
l,2,fc-Trichlorobenrene
1,2-Dichlorobenzene
1,3-Dichlorobenzene
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-------
Table 2 (Pig* 2 of 2)
Grouxtdwater
Chemical
Phthalatei
Bia(2-ethylhexyl)phthalate
Di-n-butyl phchalate
Dl-n-oeeyl phtfaalate
Diethyi phthalace
Dimethyl phthalace
AGIOS
Benzole Acid
4-CMoro-3-Hethyiphenol
2-Methylphenol
4-Hethylphenol
2,4-Dlmethylphenol
Phenol
PESTiaPE/PCBa
4,4'-DDE
4,4«-DD0
4,4'-DOT
Endosulfaa Sulfate
INORGANICS
AluBima
Anciaony
Arsenic
Barium
Berylllua
Boron
Cadmium
Calcium
Chroniua
Cobalt
Copper
Iron
Lead
Lithiua
Magnesium
Manganese
Mercury
Kolybdenuo
Nickel
Potassium
Selenium
Silver
Sodium
Strontium
Thallium
Vanadium
Zinc
Cyanide
Monitoring
Uells
X
X
X
X
X
X
X
Residential
Wells
Surface
Water
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X*
X
X
X
X
J-
X
X
X
X
X
X
s-
X
X
X
X
X
Sediment
X
X
Caa
Surface
Soil
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
X
'Found in one residential well (Phase I); well was replaced.
CLX791/43
-------
Table 3
SUMMARY OF UPPER AQUIFER INORGANIC CONSTITUENTS
CLP
Range of
Observed •
Detection Background
Liait Concentrations
Constituent
Alualnua
Arsenic
Barium
Boron
Cadaiua
Calcium
Chroniua
Copper
Iron
Lead
Lithiua
Magnesium
Manganese
Mercury
Nickel
Potassium
Silver
Sodiua
Thallium
Vanadium
Zinc
(ug/1)
200
10
200
80
5
5,000
10
25
100
5
10
5,000
15
0.2
40
5,000
10
5,000
10
50
20
(ug/1)
150-310
151*
13-28
[401 5
5.3
45,000-115,000
4*6 b
[»Y
[501°
14-38
(5J
19,000-47,000
4-44
[0.11°
[201*
91f
[SI*
3,800-4,500
[SI*
3.4-4.4
64-10,000
Range of
Observed
Downgradient
Concentrations
(ug/1)
120-1,100
10-16
4-450
82-170
0.5-6.4
24,000-220,000
4-19
8-97
320-21,000
5-260
12
8,500-250,000
4-2,320
0.2
15-23
690 - 62,000
27
1,300-840,000
1.8-2.2
3.4-9.8
45-18,000
Frequency of Downgradient Detections
Total Number
of
Detections
6
4
17
2
5
25
7
10
8
5
1
25
15
1
2
17
1
17
2
5
21
Number of Detections
an Order of Magnitude
Above Background
0
0
2
0
0
0
0
0
7
1
0
0
10
0
0
3
0
12
0
0
0
?Based on monitoring veils OWB, OWC and MC1S
"Element not detected in background; use 1/2 of detection limit for
order-of-magnitude comparison.
C8ased on monitoring wells OWA1, MW1A, MW3, MH4, and MW7; S. Dains's
abandoned well; residential wells RW04, RW05.RW07, RW08, and RW10; and
.Phase II monitoring wells MC3S, MC4S, MC5S, and MC8S.
^otal possible number of detections Is the total number of dovngradient
samples taken in both phases (equal to 25).
Mean value of background samples used for order-of-magnitude comparison.
CLI717/80-1
-------
Table 4
SUMMARY OF LOWER AQUIFER INORCAKIC CONSTITUENTS
Constituent
Aluminum
Arsenic
Barium
Boron
Cadmium
Calcium
Chroaiua
Cobalt
Copper
Iron
Lead
Lithiua
Magnesium
Manganese
Nickel
Potassium
Sodiua
Strontium
Zinc
CLP
Detection
Limit
(ug/1)
200
10
200
80
5
5,000
10
6
25
100
5
10
5,000
15
40
5,000
5,000
10
20
Range of
Observed
Background
Concentrations
(ug/1)
110-160
[5P
11-1,200
(40)
0.6-0.8
65,000-762,000
3-76
[318
6-28
500
3-28
10
23,000-33,000
1-22
120}*
13,000-180,000
2,700-59,000
79-84
110-6,300
Range of
Observed
Dovngradient
Concentrations
(u«/l)
...
18-2.9
10-54
54-160
0.3
25,000-103,000
7
7-21
500-3,900
2
12-13
10,000-58,000
19-390
...
560-9,300
9,500-100,000
110-120
12-370
Frequency of Dovngradient Detections
Total Number
of
Detections
0
2
6
3
1
11
0
1
7
3
1
3
11
7
0
6
5
3
8
Number of Detections
an Order of Magnitude
Above Background
0
0
0
0
0
0
0
0
0
0
0
0 .
0
2
0
0
0
0
0
'Based on monitoring wells OWD, MW6, MC2D, and MC7D and residential
.wells RW01, RW02, and RW03.
"Element not detected in background; use 1/2 of detection limit for
.order-of-magnitude comparison.
cBased on monitoring wells MC3D, MC4D, and MCSD and residential
.wells RW06, RW09, RW10, RW11, and RW12.
Total possible number of detections is the total number of downgradient
samples taken In both phases (equal to 11).
"Mean value of background samples used for order-of-magnitude comparison.
CLX717/80-2
-------
TO PERE-MARQUETTE
RIVER
WETLAND
AMCA- HEADWATERS
OMNISCAEEK
LEGEND
GROUND CONTOUR
PHASE I SURFACE WATER AND
SEDIMENT SAMPLING LOCATION
PHASE I AND PHASE II SURFACE
WATER AND SEDIMENT SAMPLING
LOCATION
PHASE II ONLY SURFACE WATER
AND SEDIMENT SAMPLING LOCATION
STREAM
STRUCTURE
APPROXIMATE LANDFILL BOUNDARY
SCALE IN FEET
FIGURE 9 |
SURFACE WATER AND
SEDIMENT SAMPLING LOCATIONS
MASON COUNTY LANDFILL Rl/FS
-------
Hie lower aquifer - Seven monitoring wells and seven residential wells are
screened in the lower aquifer in Phase I, no TCL organic contaminants were
detected in the three- residential wells and therefore these wells were not
sampled in Phase II. During Phase I, five VDCs and three SWDCs were
detected in RWD6. The State of Michigan replaced FW06 (screened at about
130 feet below ground surface) with a. new well screened at about 365 feet,
and. no TCL organic contaminants were detected in that new well during Phase
II. FW10 was also replaced between Phase I and Phase II. lhat well and all
other residential wells screened in the lower aquifer die not contain TCL.
organic contaminants.
Trace concentrations of five VDCS were detected in two of the three
monitoring wells located along Iiman Poad. Benzene and tetrachloroethene-
were detected in MZ3D and MC4D at concentrations of 2 ppb- and 1 PFb,
respectively. The other compounds detected in at least one of these wells
are 1,1-dichloroethane (1 ppb), 1,2-dichloroethene (2 ppb), and
trichloroethene (1 ppb)- These results suggest that Site-related organic
contaminants are being transported into the lower aquifer.
Table 4 summarizes the inorganic ~ constituents in the lower aquifer.
Manganese was detected at levels one order-of-magnitude greater than
upgradient levels in MC4D and RW06 (Phase I). This is consistent with
organic data indicating that contaminants are migrating to the lower
aquifer.
b. Surface Water
As discussed above, surface runoff from the landfill and groundwater flowing
beneath it discharge to the headwaters of Iris Creek: about 500 feet north of
the landfill. The largest number (eight) of TCL. organic contaminants was
detected at SW04 during Phase I (see Figure 9 for all surface water and
sediment sampling locations. Sample SW04 was collected at the discharge
point of the buried 24-inch storm drain. In Phase II, only chloroethene (2
ppb), xylene (4 ppb), and 1,1-dichloroethane (3 ppb) were detected at that
location, indicating a reduction of total VDC concentration from 220 ppb to
9 ppb. The contaminants at SW04 are representative of groundwater just
south of Iris Creek, near Babbin Pond based on observations that indicate the "
24-inch drain pipe is buried below the water table.
NO TCL organic contaminants were detected downstream, in Iris Creek with the
exception of 2 ppb toluene at SW01, about 1,200 feet downstream from Babbin
Pond, during Phase I. Trace concentrations of chloroethane (3 ppb) and 1,1-
dichloroethane (3 ppb) were detected in Babbin Pond in Phase II, but" no
organic compounds were detected in Babbin Pond in Phase I. Three TCL.
organic contaminants were detected in the wetland, area during Phase I;
however, Phase II results did not show organic contamination, in that area.
The number of TCL inorganic constituents and their concentrations were
generally higher in the wetland area and Babbin Pond than further downstream
in Iris Creek or in Phase I background sample SW07. Samples taken from the
wetland area and Babbin Pond during both phases contained arsenic (3 to 13
-------
8
ppb); nickel (19 ppb) and chromium. (4 to 13 ppb>) at this location in Phase
I. Elevated concentrations of iron, manganese, and potassium found at SW04
during both, phases support the hypothesis that the 24-inch storm drain is
intercepting groundwater.
3. Sediment
Volatile organic compounds, semi-volatile organic compounds, and pesticides
were detected in the sediments in the wetland area, Babbin Fond, and an
upstream location (SD04) in Iris creek. Toluene was found in sediment
samples throughout that area. NO TCL. organics were detected at either
downstream, location, in Iris creek.
The only polycyclic aromatic hydrocarbons (PAHs) detected in any of the
sediment samples were found in Phase I at SD07. The pesticide 4"4'-EOE was
also detected at that location. Based on the topography of the Site area,
SD07 is not affected by drainage from the landfill and these contaminants
are probably from another source. The FAHs may be products of runoff fronn
Bradshaw Poad (asphalt surface) and the EDE is probably indicative of
pesticides used in the orchards.
Concentrations of chromium, lead, and nickel were all relatively high in the
wetland area compared to levels detected in downstream samples. However,
the background sample SD07 had similar concentrations of these inorganics
constituents. Arsenic was detected in four Phase II samples, but those data
are questionable because of a problemi encountered with laboratory
procedures.
4. Surface Soil
Surface soil samples were taken only during Phase II. Few TCL volatile
organic compounds were detected in surface soils. Toluene contamination
appears to be most widespread, but that might not be attributable to the
landfill, as evidenced by background levels. EETT was detected in the slopes
north of the landfill. Tne presence of DDT and. other pesticides at
background locations indicates that pesticides were used for agriculture in
the area. Sample SS17 (gully No. 3) was the only sample to contain PAHs as
well as a wide variety of other semi-volatile organic compounds. Refer to
Figure 10 for all surface soil locations.
According to the Site background results, inorganic contamination of on-site
soils cannot be directly attributed to landfill activities. Arsenic, lead,
and cyanide were detected sporadically throughout each group of samples.
Sample SS13 in gully NO. 3 contained 890 ppn of lead. However, the median
value of lead in gully No. 3 was 2.7 ppm, and all other samples from this
slope were one to two orders-of-magnitude less. The landfill cap has the
most consistent levels of arsenic (4.2 to 8.9 ppm)-- These samples were all
taken from the clay cap, indicating that the imported clay may have
naturally occurring levels of arsenic in this range. Cyanide was detected
in very low concentrations in all three gullies, and the highest detection
occurred in the orchard east of the landfill (5.8 ppm).
-------
'.. N&$^
'<'
-------
9
5. Ambient Air And Gas Vent Emissions
The ambient air results indicate that only trace concentrations of
relatively few organic contaminants were present along the north, and west
edge of the landfill. These contaminants were present in the bacJcground (up
wind) sample and cannot be attributed to the Site. Carbon molecular sieve
ambient air samples were taken at each location in Phase II and analyzed for
vinyl chlorides. Nb vinyl chloride was detected in. ambient air samples on
or near the Site.
A wide variety of TCL organic compounds were detected in the gas vent
emissions. Trends in the data between Phases I and II cannot accurately be
stated because of the problems during laboratory analysis. In general, the
variety and concentrations of organic compounds were smaller along the
south-west edge of the Site (GV01, GV02, and GV03) and the north-east edge
of the Site (GV09 and GV10) where the landfill is shallow. Refer to Figure
11 for all gas vent and ambient air sampling locations. Higher
concentrations occur in areas of deeper fill; however, there are elevated
concentrations in GV12, GV13, and GV15. This may indicate that the
reported sludge pits were placed in these areas or that gas is migrating
southeastward from areas of deeper fill.
Organic compounds detected in both gas vent emissions and groundwater of the
upper aquifer include benzene, ethylbenzene, tetrachloroethene, toluene, and
xylene. Vinyl chloride was detected at 106,000 ppb in GV06 in Phase I. The-
highest concentration in Phase II was 2,900 ppb in GV12.
E'. Summary of Site Characteristics
The TCL organic and inorganic constituents detected during both phases of
remedial investigation are summarized in Table 2. Monitoring wells,
residential wells, surface water, sediment, ambient air, and landfill gas
vent emissions were sampled during both phases; surface soil was sampled
only during Phase II. The following generalizations can be made based on
the chemical analyses:
* A. contaminant plume extends north and northwest of the
landfill, and monitoring well chemical data indicate
little change in type or amount of contamination from
Phase I to Phase II. The contaminant plume appears to
extend from the landfill to Inman Road.
* Residential wells contained a variety of contaminants in
Phase I, and the State of Michigan has since replaced two
wells. Phase II data suggest that none of the existing
residential wells in the area contain Site-related
contaminants; however, the aquifers where the two wells were
abandoned could still be contaminated.
* Surface water and sediment contain low levels of Site-related
contaminants, especially inorganic and semi-volatile organic
constituents that tend to accumulate. Contamination of these
-------
LANDFILL
cvi* .-—.•'
^
-------
10
media is limited to the headwaters of Iris Creek and Babbin
Pond.
* Surface soil chemical data do not clearly indicate areas of
landfill attributable contamination, because background
samples contained a variety of volatile organic compounds,
pesticides, and inorganic contaminants.
* Landfill gas vent emissions contain chlorinated hydrocarbons
and benzene, ethylbenzene, xylene, and toluene. These
compounds may be indicative of the industrial sludges and
liquids reportedly disposed of on-site because they were also
detected at low concentrations in the contaminant plume north
of the Site.
* Off-site air quality is not affected by the landfill
according to off-site ambient air sampling.
F. CFRCTA Enforcement
Notice letters informing potentially responsible parties (PRPs) of their
potential liabilities and offering them the opportunity to perform the RI/FS
were mailed via certified mail in August of 1985 to six PRPs, including the
Site's owners, operators and waste generators. Qi September 6, 1985, the
U.S. EPA decided to use Federal funds to conduct the RI/FS due to the PRPs
refusal to participate. Ine U.S. EPA. contracted with. CH2M Hill to conduct
the RI/FS under contract number 68-01-7251, work assignment number 006-
5LE3.0.
Negotiations for the remedial design/remedial action (RD/RA) with the PRPs
are presently proceeding according to the U.S. EFA general guidances and
policies.
III. GGFMJNnY RELATIONS
A RI/FS public meeting was held on November 13, 1986 to inform, the local
residents of the Superfund process and the work to be conducted under the
RI. No major issues were raised by the community at this meeting.
An information repository has been established at the Ludington Library, at
217 E. Ludington in Ludington, Michigan. According to Section (k)(l) of
CERCIA, the Administrative Record is available to the public at the
Ludington Library.
The draft FS and the Proposed Plan were available for public conment from
August 8, 1988 to August 31, 1988. A public meeting was held on August 17,
1988 to present the proposed plan and FS. Comments received during that
public comment period and the U.S. EPA's responses are included in the
attached Responsiveness Summary. The provisions of Sections 113(k) (2){i-v)
and 117 of CERCIA have been satisfied.
-------
11
IV. SUUH£ OF THE. FS\SJHiiJTY
The exposure pathways and associated risks front hazardous substances at the
Site are addressed in. the Site risk assessment in the RI Report and are
summarized in the FS Report and in this Record of Decision Summary. en the
basis of the exposure pathways and risks identified by the risk assessment,
two operable units or pathways were selected at the Mason County Landfill
Site: 1) landfill contents, and 2) groundwater.
The landfill contents operable unit addresses all materials contained
beneath the existing Site cap, such as general refuse, sludges,
possible buried drums and the underlying soil contaminated by leaching.
The landfill contents operable unit also addresses gas generated by the
decomposing buried waste. The general remedial action goals for the
landfill contents operable unit are to prevent direct contact with
contaminant sources and to minimize future release of contaminants.
The groundwater operable unit addresses the shallow and deep aquifers.
•Die general remedial action goals for the groundwater operable unit are
to minimize migration of contaminants in groundwater and to prevent
exposure to contaminants in residential wells.
Surface water, sediment, and surface soil are not addressed as separate
operable units. Although, potential risks to public health and the
environment were identified for those media, based on conservative exposure
estimates , the estimated risks are not sufficiently high to warrant remedial
action. Contamination of surface water and sediments is mainly the result
of the discharge of contaminated groundwater to the wetlands area and Babbin
Pond. Contaminant concentrations in those areas would be reduced if actions
were taken to minimize the leaching of contaminants to the groundwater or to
prevent migration of contaminated groundwater to these areas. These issues
are addressed by the landfill contents and groundwater operable units.
Based on the information developed on the Mason County Landfill Site, U.S.
EPA. believes that the best approach to this Site is to separate the two
operable units, landfill contents and groundwater, into two separate
remedial actions. This approach is cost effective and consistent with a
permanent remedy. - :
The alternative chosen by the U. S. EPA. in this Record, of Decision primarily
addresses the landfill contents operable unit and defers the decision on the
groundwater operable unit until more information is available.
The alternative chosen in this RCD is considered an interim remedy and is
consistent with the eventual final remedial action for this Site. Based on
available information, the U.S. EPA. believes that the selected alternative
for the landfill contents operable unit will meet the previously mentioned
general remedial action goals for the landfill contents operable unit. The
selected alternative is cost effective as it may greatly reduce the extent
of future groundwater remediation. The specific components and evaluation
criteria of the chosen interim) remedial alternative are detailed later in
this document.
-------
12.
Another Proposed Plan and PCD will be issued at the conclusion of the
groundwater operable unit to announce and select a final remedy for this
Site. Currently there is not enough data to select an appropriate remedy to
address the groundwater contamination. ffore data is needed to define the
extent of contamination, evaluate the effectiveness of an upgraded cap,
track the concentration of contaminants in groundwater over time, further
define the relationships between the identified aquifers and further
investigate the relationship between the shallow aquifer and the surface
water bodies near the Site. Further groundwater monitoring along with
surface water, sediment and gas vent sampling will be conducted to evaluate
the requirements for the groundwater operable unit, and the effectiveness of
the chosen alternative for the landfill contents operable unit.
V. STIE RISK ASSESSMENT SOWRRT
Within the RI, a Risk Assessment chapter details a baseline risk assessment
that addresses the potential threats to public health and the environment
from the Site associated with the no action alternative.
The potential exposure pathways, the means by which contaminants may move
fromi sources to receptors under both current and potential future land use
conditions, were identified in the exposure assessment. After evaluation of
Site conditions, the following pathways were identified as having potential
to be completed under the no action alternative and were addressed in the
risk assessment:
* The release of contaminants from, the landfill to the
groundwater, the migration of these contaminants to the
residential wells downgradient from the Site, and
subsequent human exposure through groundwater use.
* The trespass of people onto the Site where they might cone
into direct contact with contaminants present on the ground
surface.
* The release of contaminants fron the landfill gas vents to
the air where they could be inhaled by Site trespassers.
* The release of contaminants by groundwater discharge to the
wetlands, where people or wildlife could come into contact
with them.
* The future development of the Site resulting in direct
contact with contaminants unearthed during excavation work.
* The future installation of residential wells on-site or in
areas adjacent to the Site, resulting in exposure to
contaminants in the groundwater.
-------
13
The following exposure pathways were not considered to be significant
because of prevailing Site conditions:
* Exposure of people through fish, consunption. Few
contaminants were found in upstream locations (Babbin
Pond). Iris Creek is not deep enough to support large
fish. There is no evidence that contaminants have
migrated from the Site to the Pare Marquette River.
* Exposure of off-site residents through inhalation of
contaminants released from the landfill gas vents. The
contaminants will be substantially diluted by mixing with
air.
Potential hazards to human health, front the Site were evaluated for both.
carcinogenic and noncarcinogenic risks, concentrations of contaminants in
groundwater were also cotpared to drinking water standards and criteria.
Human health, risks for the Site are summarized in Table 5.
Table 5 indicates the contaminants of concern at this Site for each exposure
pathway. In summarizing the exposure assessment, Table 5 mentions the
estimated potential carcinogenic and noncarcinogenic risks at this Site.
More detailed explanations and rationales involving methods to determine
risk at the Site are located within, the RI Report. Risks associated with.
background (areas not believed to be influenced by the landfill) levels are
not addressed. Potential environmental concerns associated with the Site
are only addressed in a general qualitative method since no formal
evaluation of the plant and animal communities on-site or in surrounding
areas were determined to be necessary during the RI.
The RI report further details the baseline assessment for the site and the
baseline summary indicates the following areas of concern:
* The use of groundwater from wells located between the
landfill and Inman Road may result in adverse health
effects. This concern comes from the detection of
carcinogens in monitoring wells at concentrations
greater than those associated" with a 1 x 10~7 excess
lifetime cancer risk, the presence of noncarcinogens at
levels higher than those needed to exceed, reference dose
values, and the presence of two chemicals at levels that
exceed MZLs.
* The ingest ion of lead found in one surface soil sample would
exceed the reference dose value. However, all other
detections of lead in soil were below a level of concern.
* The release of vinyl chloride from gas vents to the
atmosphere is a concern only under conservative exposure
conditions and only for individuals who come onto the Site.
-------
TABLE 5 (Page 1 of 2)
Summary of Risk Assessment
t»po»ut« folnt
Pi Ink Ing color, olfillo
f»*ld*nllot o»ll
L*orklnof iroundvolor
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bpoord fopulolloa
Poildonti
«Uk O»orocletlt«tlo« tuoaonr
•U>o ••raodod In 0*0 reoldeotlol voll lor codoltM,
leod, and line IPkoio II.
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oqulfrr
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•rll >ci*«n«4 In lovtr
li»9*»t!l»k •
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•* circlMf*«i ••!• 4cl*cli4 In wy
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I* pall I* (ko r«pl*c«B«nt of l>o
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JO-1*ft oiposur* to Itio kl«h*il dtl«cl*d
concciilfilloni ol ill corclnoftnf IR ill
•onlloilnf ••III. t>po(uil Iflllnf onuatl
Ikit onillo r**ld«nllil d««olop>cBl >lll
occwf ond Inot dflnk|*f luppl* call* oilI
k« ln«UII*d. Tkll U uillkolf ktcout*
Iktto li Illllo pitiiuro lor risldtntlil
d*>*lof>Mi«t lo (k« iroi. Iko I end li to**4
lor igrloilliiril mi. lod Iko prop*rlf li
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concentr«tlon( of ill eorclnoftoi lo ill
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Ikol ooilU rilldMllll do«olop*oni olll
•orar ind Ikit 4rl«kl»f lopplf ••III >lll
bo loitillrd. nil U uillltlr btriuii
tkor* It lltllo proiwr* lor rotld*«tlol
doiolopMit lo Iko or«o, Iko lond lo toned
(or ogflcMUvrol 11*0, ood Iko pioporlf ll
owned bf • pidtllc Ifonqr IH«*on Countr
OMl.
bpoouro br latoitlon or dlroct canlocl
I lolled bf noil ill* of Motby population.
tlooi Irlo Crook lo loo (hollo* lor ••lo»lnf
•od •eciil U tobbU rood llollod lo
Iroipooaori. Huoon ovpoturo liooi Ingtillon
•I contoaloolod Iquotlc orgonliai ll
•ollktlf.
Totol chioolMi coocontrot loo uoro lll»lr lo
bo U tko Irltolont for* Ikon koio»ol«nl
(or* bocoui* •( reduclnf noluro ft ivrloro
•ilir I* ill* ir*i.
bpomro oolllnf li roclrlcltd lo illo
ir*tpoi(*ro U.f.i fclkori or ploflno;
dilldrtnl ond II o»uo*i ln««tlon of
O.I fiw/dor ol «ol| Inonrorclnogtnlc
ollocltl i«4 O.I «>o«/dor lor U «»/ft lor
S |*oio Irorclftoftnlc ollrclil. Nl«h l**d
co*r*nliollon drlvclod ol o«lr on* i»»pll«9
point *»r bo irp(*i*nlol|»o ol • •••II,
loccllird oiti of loll. t>*ro«o ontll*
ronconlrtllon* ol ronlooloonti »*ro b«lo»
«pp*r b»c»ffound cenrcoliollooi
l**oo • 1 ilondotd doTlollonil ompl for
•Ickol ond lonodluo.
-------
TABLE 5
Summary of
(Page 2 of 2)
Rfsk Assessment
e»pomro feint
SrdUrai
lipotuto rotkmf
ln««*tlow
Inhololloo
tipoood
Troipofiot*
Troopoiforo
»Uk ClioTOC«orll«tlo»,
No »IO» oinodvd.
Totol Cftc*«« II lotto* Coocor »Uk • I • 10*'°
No RID* •»cndrd.
Toll I Bie»«i tlUIlM Cancer •!•» •
S • lo"
I— cMiccr rl«k «u« Millr U >Url
chlocldtl
I • IO"7 ln»*« II— cwc«r rlik *M
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f«lo« eipomro ••Mint olollfr to lk*l lor
• Ho Iroipoitoio, Iko ••• tonl coocvnlK-
llono oovld bo 4ll«lonco.
CIT7*I/*|
-------
14
VI. DESQUPHQT CF REMEDIAL KL3SSSKTTJES
A. Screening of Alternatives
. 1. Screening Criteria and Goals
Screening: Numerous technologies and process options were evaluated for
applicability at this Site. These technologies and process options were
screened initially for the following to determine if further consideration
was warranted:
* Inability to achieve remedial action goals.
* Failure to meet federal or state ARARs.
* Impracticable nature or difficulty of implementation given Site
contaminants and physical conditions.
Figures 12 and 13 illustrate the initial evaluation of the technologies and
process options for the landfill contents and groundwater operable units.
Goals: The general remedial action goals for the landfill contents operable
unit are to prevent direct contact with contaminant sources and to minimize
future release of contaminants. Specific remedial action goals are:
1. TD prevent direct contact with landfill sources that have
contaminant levels exceeding target concentrations for protection of
public health from the effects of noncarcinogenic contaminants (based
on reference doses), or excess lifetime cancer risk in the range of 1 x
10~4 to 1 x 10~7.
2. To prevent contaminant migration from landfill sources to drinking
water aquifers that would contaminate these aquifers to levels:
* Greater than maximum contaminant levels (MCLs) ;
* Exceeding the lifetime health advisories ;
* Exceeding reference doses for protection of public health fromi
the effects of noncarcinogenic contaminants; or
* Resulting in an excess lifetime cancer risk of 1 x 10~4 to
1 x 10~7.
3. To prevent contaminant migration from landfill sources to a surface
water body that would result in contamination levels greater than the
Ambient Water Quality Criteria.
4. To control future releases of contaminants to an extent that
ensures protection of human health and the environment (SARA Sec. 121
(d))
-------
OPERABLE tMT
GENERAL
RESPONSE ACTION
REMEDIAL TECHNOLOGY
PROCESS OPTION
No Action
ConlOiivnMI
None
I • "" ~" '" ' "I AN da*d« lo* p'Oportv »4thtn pOt«n|ioJlp eon-
I . I I Loqol ««»tr.cl.oni I tom«ol*d or*a* »avM indwtfo kmilalio**
•j ACC... Ra.incTioTr] ~ — " "•""'
I [ f«nc*ig j ^XetnSiS* a* wwlr**^* l*"tfl* ****
Surloct Conl'olt
••i«l«iQ landfill coniou«t t»
_ I ••itltftg landfill
•9totjmq/R«vdq*tolKX| »ot«* t«iew»f*
---_ J .___
Soil Co.»
Copping
Spray Opplnlh«l.c Mtm [ •»»• »oii i«i«»i U pro^d* oraoion ond
| Compact*d clay and •ynlhatlc mombrona bofflar
n. Mam.-Qay I ea««r*d win »«4 i«|««a la p/o«do araaidn
^ ^ ^ S S~ f S f~7TJ~f7J\
yr&£fa'&)Mi
'/^T'/^T77///"/7777) Trancfi la a»coMH*d •"•• fll»d «ltn o Mnl(
Sorf-Btnl. Slurry WoU^j ••>*' •>»"» francn ia kackfatad -Mh a oo*<
peHwn ol dfrftcd
fc'/ x"/1^ x-/^/- J'X^T-^/'J'-/./] Con trotted in|ccIiOO ol Hwfrr in noiCl«d
i 1^ BtQCti OilpTOC*n-)«nl^j ln^el»on no*at 10 p'OouC* noritoniai OO«»*«
K^jH'K¥?'/}yyft I ^'^'^'/^V^y^ **n*olh ln< cortlomtnwftit
SH« tftll mo** a nong.ng -O»
in*ff«ci<«o
OitcontMwOwi coaming top*ft lo k*r ^'O. ontf
•Irong wdicot yroo**nl» mo^* a n anting mtttt
OifliCwll 10 O«l*«ntin* >n|*gfil|r ol DO'"*' Not
• KOl'f oo*ic wntlt b«n*alh londli»
O'lliCwtl la dalvrmtn* ini*grt|r of DO">«> rtoi
*M*«I.<* b*COw»* Ot in* 00(*"C* Df (Onl-»«0u»
FIGURE 11 (PAGE 1 OF 31
APPLICABLE REMEDIAL
TECHNOLOGIES
AND PROCESS OPTIONS
FOR THE LANDFILL CONTENTS
-------
3PERA8LE UWT
GENERAL
RESPONSE ACTION
REUEDUI. TEOKXOQY
PROCESS OFTON
peacnrnon
lonOI.ll
(Conl.nuro)
Remove!
Trtolmtnl :
" i ConfUuClion
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•• a bochho* o*
in S-iu lr«oim»MV3
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Y««f«ftStt«f{\ fonol* lor d*0*od*l.on «l oiaonict oroouc* olW fM>l.dou. •ybfto'K**.
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^%
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or injoellon. Cotiocllon of ••iroci ot
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lion of 104 cOAlon^nontt •«« »o«or
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-•'onI ^o»*Alf for fir* ond tftorl tkcwlno^ r«tp*cit*««r
Not OPBKCOO4* lo Oil lyplt Ol ConlomMgnit
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Contomlnonli.
Not oopikooi* lo on IM»«* of cenlomM«ni»
on*tl* Of *rwmm*d •*•!*. rf p«*»*n|.
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i~* Orfonic motoriol* olocod U controMvd on«won-
mon» with *«*iUon of nuUlMll ond •*• I* <
micro
nucrobW d*oyod«tion of orfOAkt.
Ih* I
Of ion*f» conionl*.
FIGURE IX (PAGE 2 OF 31
APPLICABLE REMEDIAL
TECHNOLOGIES
AND PROCESS OPTIONS
FOR THE LANDFILL CONTENTS
-------
OPERABLE uurr
LOrtdliil Contdftl* I ii i.
(Combed)
GENERAL
RESPONSE ACTION
1 1 *• 1
- Qispoioi | ii •
REMEDIAL TECM40LOQY
I Thd'mol 0«s true lion 1
.
,?„,., 1
1 1
PROCESS OPTION DESCRIPTION
1
^"*" "T>yyyyPa'dP*'9nv'yyyyl PO'mongonoit mlroOuCta into O contactor Wi««t
•••JX/Soivtnt C»UoclK>o^j mwot •«!!» tondr C'iroci it COMOCIOO ond
___T pftt*ftt^-OD'« SorbonlsXJ conlomMtonl* art mi,»d .i|h Mil Utt ol mognttic
rt«no«at.
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Mhermpl ValoliliialionH VOC .wolnngluin « a iw «r"9 »"•>
t/^/xf7>y^yyyy^»^
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•«— ^™J FUolion | comonl. motion fl«»t. or voriowl aroprMlo/jr proawct
•i ••— 1 P>roty»it 1 dlmotpnoro lo prodwco oior ro»idu« ond ««4oU* org«
1 floior KMn 1 So»id» and Uauid* or* ltd inlo • nwUafflOr routing
Xol'do d ttau'do o fod bilo h1 n
— f uuiiipi. H.O/II. | ^jr/^SwV^n'i.i'.'.'i^vEr^,
, Fluidutd B«d | ., ^a ^^. hfal |rontlvr ^tf C0rnb3;lion ^e^,
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^^tiqu«O ^*^ yvyyvl tltom and Owrntd •» •u«p«ns>on.
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^^•— J/'LiC*" g*0 Londlor Tiy/! 9>o4OQrco' otg>ooolc(o*orgonifni in
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1 iw, i
APPUCABUTY
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•w»«ionc*i No! •«•>!•« tor lr*«im*nl «l •w
* ooa »li«t ol m«i»rlo*r
Noi opplicoeit lo 0« l|*«» Ol contorvirfionli
lOwnd on»>l« Not •'OClical an o l«ra« »#•
Not twll** lor Irvotmartl O* tO**« O» *•«
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•*!*• or odd »>t«t ol mot*****
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tnot mor «»' •••*' !** *or$t %*oni.lr on»iU
Not i«cnn<«n> prociicot on torgt tcot* lor
Otlirwction of coniomMtont lyp«t lOwna ont.ic
Applicability IwnlICO tO It* COnlOm^onl <*>••
tnoi mor A«* fill »n l«rg* •uantily OA»I!<
AppltCOO^lr l*nil»d le !•• coniom^iQni Irpci
inot rn«|r nol *•••! M targt Qwoni.tr ontiit
r»oltntloitr ««ooit
o* warp 'org* t*«ci'r 0'
conion«>no»il
FIGURE 12. (PAGE 3 OF 31
APPLICABLE REMEDIAL
TECHNOLOGIES
AND PROCESS OPTIONS
FOR THE LANDFILL CONTENTS
-------
3PERABL£ UNfT
Cro«>no*»ol«r
GENERAL
RESPONSE ACTION
No Ac)
Conl'ol>
Co»n
tCMEIXM. TEOHOLOQY
Noo«
UlxnoK ttolw
PROCESS OPTION
DESCRIPTION
APPUCABUTY
S*U ftMlUcliong | [
|l«go> >«it'icliont lot •>op«ilr
COA1o<**«U0 OiOQ* *Owt« nclu
o* MM of propwly.
Uonilpftnq Welil | io»i»pi»fl ond !••)•«
•fX/'MuniCipol Supply
OH«CII< -t'l.
Action AOI
10 ini*fc«pl
«A« c*««cl cool •mine! •« o/owndv«l«r.
.......... *r»»om of infection ond ««lrocllon •>••» w««d lo
_; .1 iir|«nu I* f
Mm*, or I*M oi
[ Trool. 6«d«| lo fomovi
Of RtOCllOn/^ VwCtt •« oton*. pcrmangaAOlc
l*«np«f«lwr« !•• cold lo •wpporl
th.
conlom*to»on loo do^i for
of np«oo,on
(too looclionB m*jr pfo
ln»wn
Co"1"
FIGURE >i IPAQE 1 OF 21
APPLICABLE REMEDIAL
TECHNOLOGIES AND PROCESS
OPTIONS FOR GROUNOWATER
-------
3PEHABLE UNIT
GENERAL
RESPONSE ACTION
BEMEDIAL TECHNOLOGY
PROCESS OPTION
DESCRIPTION
(Continued)
Irtatfntnl
o,.~ » I»I.M I *M»»OI«on Ol Cn*m • Quit*'4 lo r.
PfQCipilOliOft | iOI-tei,;i, Q| m( congl.tMtnl
A* Stripping I poci>*d .
Slcom
_ I »•• j On i< I* 0«»c*>O'g«
'• ' I ^6ll*iiff'6iscn»9c-;^
CfKDOn AdtO'pliOO
IO Oif *lr »t«O« !• •»,
POTW
RCRA rocili
on ol
•Alp IA« COTBOn »t*IOC«
Otti^iCol O«HIOI»OA ol
ut««9 on Q*>d,ting ogcnl SwCfi ai p«ro«*O«.
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l«m0«'*lMi« «na pf«t»w'« cpnalltan*
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••cnong* ol ion*
In* *4lor.
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^ol«nlio»y wool* (O» O*fOr<< c on I *m wort It.
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Poi«niioi>r «OO'» t wtorgontc cor>tominoni>
or* lron*l**r«d from IN* wotor iorg>* cpniom««*nl* moy •• <*rn*d Oll*il*
or fvrrayi ammoniwm
Thwmol •••IrwCliort *l OffOAic conl
w«Mf onjr on* *l mort^ roocior IM»
OQw«Ou* •«•!«»
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lr*oimonl.
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locHtly lot lr*olm«nl ond/or ditpotot
fr**l orowrtd*Ol*< Ol point ol w«* «iirt
norn* *on ••cnongt o* cor Don oatorplion
wfttl*
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'**'»'in'-'rl.ftny^i O.««io««o contpm-»oi«a o/o-nd-oi*. lo
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i cno/aci««»liC> ond
vi« «OI •upporl combuilion
or* loo 10* lo o« cono^oro
Pol*nl>oiiv vtobl*
0««D OOu>l«' •• mined i
FIGURE '£ (PAGE 2 OF 21
APPLICABLE REMEDIAL
TECHNOLOGIES AND PROCESS
OPTIONS FOR GROUNDWATER
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15
5. 1b permanently and significantly reduce toxicity, mobility, or
volume of hazardous substances (SARA Sec. 121 (b))
Hie general remedial action goals for the groundwater operable unit are to
minimize migration of contaminants in groundwater and prevent exposures to
contaminants in residential wells. Specific remedial action goals are:
1. To prevent exposure of receptors to contaminated groundwater.
2. To prevent migration of contaminants fron the shallow and deep
aquifers to off -site receptors that would result in exposure:
* Greater than the *£Ls;
* Exceeding the lifetime health advisories;
* Exceeding reference doses for protection of public health
f ran the effects of noncarcinogenic contaminants ; or
* Exceeding a lifetime cancer risk of l x 10~4 to l x 10~7.
3. To prevent migration of contaminants from, the shallow aquifer to a
surface: water body that would result in contamination levels greater
than the Ambient Water Quality Criteria.
The technologies and process options carried forward through the initial
screening were evaluated further based on effectiveness, implementation, and
cost.
1. LflTlflflll Contents Op?r?i?Te Unit
The technologies and process options evaluated for the landfill contents
operable unit and corresponding evaluation summaries are as follows:
a. Access Restrictions
Access restrictions are intended to prevent prolonged exposure to or direct
contact with contaminants, to control future development and excavation, and
to prevent the installation of water supply wells. These objectives would
be accomplished by placing legal restrictions on the property and enclosing
the Site with a fence. Access restrictions are an effective method of
limiting public access, but they do not reduce the level of contamination
and are not protective of the environment.
A Site fence with locking gates and warning signs can prevent access to the
landfill by humans and some animals. Its effectiveness depends on future
maintenance. This action can protect the integrity of the landfill cover or
cap, and it helps prevent direct contact with contaminants. Fences are
easily installed at low cost.
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16
Legal restrictions would control the future use of property, and their
effectiveness is dependent on continued implementation in the future. Legal
restrictions are subject to changes in political jurisdictions, legal
interpretation, and regulatory enforcement. However, if legal restrictions
are properly implemented, they provide low cost protection against direct
contact with contaminants and prohibit installation of water supply wells.
Both legal restrictions and a Site fence at the Mason County Landfill Site
would be effective for protecting human health, easy to implement, and low-
in cost. It was not possible to screen one in favor of the other because of
their significantly different effects on remedial action at the Site, so
both were carried forward for assembly into alternatives.
b. Containment
At the Mason County Landfill Site, containment would be limited*to surface
controls and capping. Tnese technologies would be effective at minimizing
the potential threat of direct contact with surface contaminants. Tney
would address the issue- of surface water management and could reduce surface
infiltration. Some degree of protection against surface infiltration has
already been achieved by the single layer clay cap installed in 1979 and
upgraded in 1984-85. However, large settlements have created areas of
ponded water and cracks along the landfill perimeter.
Ine existing clay cap can be incorporated into the final design of any of
the contaminant technologies considered for the Site. Hie options range
from a maintenance procedure (regrading and revegetation) to a multilayer
cap with two low permeability barriers that are protected from the
environment by overlying soil layers (soil-synthetic membrane-clay cap).
The main difference between the technologies is the degree of protection
provided for the low- permeability layer.
Regrading and revegetation with a soil cover would reduce leachate
generation, but, regrading and revegetation with a soil/clay cover would be
more effective at reducing surface infiltration. Regular mowing and
periodic inspection and maintenance would, be required for either option.
Maintenance would consist of filling depressions with soil and reseeding.
Since the costs for both options would be low and both could be easily
implemented, the regrading and revegetation option was carried forward
because it would be more effective.
The capping options would be an improvement over regrading and revegetation
because the low permeability barrier would be protected from environmental
conditions that can create cracks. Ine soil-clay cap and the soil-synthetic
membrane cap would have roughly equivalent performance, and the soil-
synthetic membrane-clay cap would have the best performance. Ihe technical
feasibility of each cap does not vary greatly; routine maintenance would be
similar and each cap would probably require replacement because of
settlement cracking. It has not been demonstrated that the risk of
contaminant release to the groundwater at this Site warrants the extra
protection and concurrent high capital and replacement costs associated with
the soil-synthetic membrane-clay cap. Ine lack of clear advantages or
disadvantages between the other two capping options makes relative cost a
-------
17
valid screening criterion, since clay is available within 10 miles of the
Site, the soil clay cap could be constructed at less cost than the soil-
synthetic membrane cap. Therefore, the soil-clay cap was retained for
further evaluation.
Gases produced by decomposition of the landfill contents beneath the low
permeability barrier layer would be vented to prevent the cap from cracking
or 'gases from migrating off-site through the subsurface. Gases are
currently vented to the atmosphere without treatment through a system of
fifteen vents. The risk to the public associated with gas vent emissions
was determined to be negligible outside the Site boundaries. A. Site fence
could adequately prevent the risk: of direct contact with landfill gases
without the need for an expensive gas collection and treatment system so a
gas venting system similar to the existing system in conjunction with a Site
fence has been considered with each containment option.
Figure 14 illustrates the cap configurations that were carried forward for
assembly into alternatives for the tfeson County Landfill Site. Hie
anticipated, frost depth was conservatively estimated to be 3 feet.
c. Removal
Under the removal response action, contaminated wastes would be excavated
and. disposed of or treated to reduce the potential risk associated with
direct contact to contaminants and migration of contaminants to groundwater.
Landfill contents can be excavated using backhoes or clamshells. Excavation
and handling operations would vary because of the variety of wastes. Waste
would be segregated into garbage, soil, sludges, and. drums (if present)
because different waste types require different handling, treatment, and
disposal. All excavated areas would, be backfilled with clean soil to a
level consistent with the rest of the Site.
There is considerable risk of worker exposure to hazardous materials during
excavation, including potential contact with hot spots (i.e., areas where
sludges and liquids were deposited) or druntned liquids and contact with
airborne contaminants. Dust and surface water runoff must be controlled
during excavation to avoid or minimize potential off-site release and
exposure. ,••-.:-
Excavation would be an effective and reliable technology for the removal of
contaminant sources at the Mason County Landfill Site. It would be
protective of human health and the environment when combined with such
response actions as treatment or disposal. However, it would be difficult
to implement and have a high capital cost because waste types are probably
mixed and the location of sludges or drummed liquids is not known. There is
no operation and maintenance associated with excavation. Excavation was
carried forward for further consideration.
d. Disposal
The disposal response action involves placing and permanently storing
excavated material in an off-site or on-site PCPA-approved disposal
-------
W63353RF\FIG 4-1 5/18/88
PASSIVE CAS VENT
UNDERLYING SOIL
REGRADE AND REVEGETATE
(Single-Layer Cap!
PASSIVE GAS VENT
UNDERLYING SOIL
SOIL-CLAY CAP
NOT TO SCALE
FIGURE H
CAP OPTIONS
MASON COUNTY I ANOFll I
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18
facility. A RCRA facility is controlled, monitored, and regulated to
minimize the potential for uncontrolled, releases of contaminants. Disposal
in a RCRA. landfill is an effective and reliable means of controlling the
migration of and exposure to contaminants. Since RCRA prohibits the direct
landfilling of containerized and buUc liquids, they would be separated from
the solid materials and treated before disposal.
The landfill contents could be transported to an off-site RCRA-approved
facility. TWO interim status- RCRA landfills near the Mason County Landfill
have reserve capacity. One is about 250 miles from the Site in Detroit,
Michigan and the other is approximately 500 miles from the site in
Cincinnati, Ohio.
On-site disposal would involve the construction of a RCRA-type ^facility on
the site property. The facility would have a double-lined* bottom, a
leachate collection system, a gas and condensate collection system, a
monitoring system, and. a multilayer cap- (Figure 15). Buried waste would be
removed and a landfill cell would be constructed before it was redeposited.
Special measures would be taken to prevent airborne contaminants from
reaching nearby residents and erosion of stockpiles from degrading the
environment. Erosion controls such as spray foams and temporary dams and
ditches could minimize these threats.
A RCRA facility would effectively control the migration of contaminants to
drinking water supplies. The facility would have to be monitored and
maintained to remain effective. Removal to an off-site location would
involve risk to the public during transportation on. public highways, and the
stockpiling of wastes on the Site would involve risk to nearby residents and
the environment. Capacity and the federal land ban are potential
limitations on off-site facilities. Construction of an on-site facility
would be less costly than the hauling and disposal fees associated with an
off-site RCRA landfill, but the on-site facility would require some
operation and maintenance. The on-site RCRA-type landfill was carried
forward for further evaluation.
e. Treatment
Treatment alternatives include < on-site and off-site thermal treatment',
biological treatment involving composting, and physical/chemical treatment
involving fixation. These technologies are described in the FS and their
evaluations as pertaining to this Site are discussed below.
On-site or off-site thermal treatment could be used to destroy organic
contaminants at the Site. Off-site incineration would be difficult to
implement because the material must be processed, packaged, and transported
several hundreds of miles. This could take up to 20 years to accomplish and
the cost for packaging, hauling, and incinerating could range from $2,000 to
$5,000 per cubic yard. On-site incineration would also be difficult to
implement because material must be prepared for feeding to the incinerator
and then ash and particulate matter need to be handled and disposed. There
is little field experience to verify costs, but they could range from $500
to $1,000 per cubic yard.
-------
HEFUSE
LtALHAIt " ' ' ' ' • • ' '
SAND •— -— »__.J
SYNTHETIC ^^-X Q
MtMUHANt < — - — - "—
100 m.l HOPE "*"* 4
/o
r*
9
CEOTEXTILE FILTER
PRIMARY
LEACMATE
COLLECTION PIPE
SECONDARY LEACMATE
COLLECTION SYSTEM
(SYNTHETIC OHAINI
CEOTEXTILE
FILTER
SYNTHETIC
MEMBRANE
GAS
COLLECTION
PIPE
DRAINAGE
CLAY
GAS COLLECTION
COVER
REFUSE
LINER DETAIL
CAP DETAIL CT
GAS VENT
GAS VENT
GAS VENT
TYPICAL LANDFILL SECTION
NOT TO SCALE
FIGURE IS
ONSITE RCRA TYPE
LANDFILL CONSTRUCTION
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19
Both off-site and on-site thermal treatments are cost prohibitive compared
to biological or physical/chemical treatment, so they were not carried
forward for further evaluation.
Composting could reduce the level of organic contamination; however, the
effectiveness of composting with respect to the degradation of volatile
organics is not well known and it could take years for contaminant levels to
decrease sufficiently. During that time, landfill contents would remain.
uncovered in windrows at the Site. Composting would not degrade heavy
metals, and certain toxic heavy metals could inhibit the biological growth
necessary for the degradation process. Thus, composting would not
effectively treat the variety of materials expected to be present in the
landfill, and the implementation time could not be predicted. For these
reasons, composting was not carried, forward for further evaluation.
Fixation could immobilize Site contaminants. Implementation would be
difficult because excavated wastes must be segregated into discrete types
based on physical properties (i. e.,. material type and size) and reduced to
manageable sizes for mixing. A. variety of fixing agents and formulas would
probably be needed to treat the expected variety of materials. Other types
of treatment might be applicable for the landfill contents but cannot be
selected at this time because of unknowns involving the types and quantities
of buried materials on-site. Fixation was carried forward as the
representative treatment option for the landfill contents.
2. Groundwater Operable Unit
The technologies and process options evaluated for the groundwater operable
unit and corresponding evaluation summaries are as follows:
a. Access Restrictions and Monitoring
•Die objectives and. effectiveness of access restrictions are discussed under
"Landfill Contents Operable Unit." Legal restrictions would be imposed to
prohibit the use of groundwater as a drinking water supply in areas
downgradient of the landfill affected by the contamination plume.
Monitoring of groundwater downgradient- of the landfill would detect"
increases in contaminant concentrations and the spread of the contamination
plume. If established target levels were exceeded, additional remedial
actions could be taken. Groundwater monitoring would be accomplished by a
regular sampling and analysis program of the existing well network. New
wells could be installed to provide data in areas between wells that are
spaced far apart. Monitoring would verify the protection of human health
and the environment and could be easily implemented at low cost.
Legal restrictions and groundwater monitoring are effective methods of
protecting human health, easy to implement, and low in cost. Because they
are significantly different, both were carried forward for assembly into
alternatives.
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20
b. Collection
The applicable collection technology for the Mason County Landfill Site
would be an extraction well system. The collection, disposal and treatment
of contaminated groundwater would prevent contaminants in the groundwater
from migrating from the Site. Hie system would, consist, of a series of
wells, located downgradient of the landfill, that will intercept the
groundwater contamination plume. Contaminated groundwater is pumped to the
surface and routed by a gravity or pressurized pipeline to a treatment or
disposal system. The number of wells, well locations and groundwater
extraction rates would be determined during the design stage to ensure
effective and efficient control of the contamination plume.
An extraction well system has moderate capital and operation and maintenance
costs and, properly designed and constructed, would be effective, reliable,
and. durable. Mechanical breakdowns during operation of the system should be
routine. Therefore, extraction wells were carried, forward for further
consideration.
c. Treatment
Treatment alternatives include off-site treatment including the use of a
RCRA. facility or a publicly owned treatment works (POIW) and on-site
treatment including physical/chemical treatment such, as reverse osmosis, ion
exchange, precipitation, air stripping, steam stripping and carbon
adsorption. These technologies are described in the FS and their
evaluations as pertaining to this Site are discussed below.
Off^site treatment would require transporting large volumes of groundwater
to a RCRA facility or POIW. The POIW is within 3 miles of the Site, so
transportation to the POIW would be less costly. However, treatment volumes
for either alternative could range as high as 500,000 gpd which would
require hauling of 50 truckloads of groundwater per day and a one million
gallon tank to provide two day storage. Because of the high volume of water
that would need to be stored and hauled, off-site treatment was not carried
forward.
None of the individual on-site treatment technologies would completely
remove both. the organic and inorganic constituents in the groundwater,
however, two technologies could be implemented together. Reverse osmosis
and ion exchange units were eliminated from consideration because of their
higher costs relative to other options. Neither air nor steam stripping can
remove inorganic constituents, whereas granular activated carbon adsorption
(CAC) can remove some of the inorganic constituents. Thus, the GAC process
is more versatile and would require less pretreatment of contaminated
groundwater. Since the &C process requires less pretreatment and is less
costly to operate than air and steam stripping because of lower energy
demands, the GAC process was retained for further consideration.
The treatment system that appears to be most suitable for the Site would
consist of precipitation and carbon adsorption, although other systems would
probably work and may be determined more suitable in final design.
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21
Precipitation would be used as pretreatment to remove some inorganic
constituents in the groundwater. The low contaminant load in the
groundwater will require high chemical dosages to precipitate the inorganic
constituents, which will generate high volumes of sludge. The sludge is
excepted to contain high enough concentrations of certain toxic heavy metals
that it would have to be handled and. disposed of as a hazardous waste.
Therefore, the treatment system, should be designed to minimize sludge
production.
Implementation of the treatment sysLeuii would, require a pilot study to
develop the most efficient balance for contaminant removal rates by
precipitation unit and. the (3X2 column. Installation of the system would be
easy because skid-mounted treatment units are available. An on-site
operator should be present to monitor for contaminant breakthrough and
replacement of carbon beds.
B. Alternatives Considered
Remedial alternatives considered for this Site are combinations of actions
and technologies that represent overall approaches to the Site problems and
remedial goals. The six technologies that remained after screening range
from- simple, low cost alternatives to alternatives more costly and complex
and. address the remedial goals identified in Section VII A of this ROD and
within the FS. The alternatives that underwent detailed evaluation are
listed below along with a detailed description of each.
Alternative 1 - No Action
Alternative 1 is the no action alternative, which the National Contingencies
Plan (NCP) requires for baseline comparison to other alternatives. Under
the no action alternative, no further remedial investigation or action would
be conducted, and the public health and environmental risks would be those
identified in the risk assessment.
The pathway of most concern is the potential contamination of residential
wells downgradient of the Site. Those wells are not currently contaminated
and do not pose an immediate public health risk, but the potential for
release of contaminants fron uncontrolled hazardous substances in the
landfill may pose a future threat. Lower public health and environmental
risks are associated with migration of contaminated groundwater to Babbin
Pond and Iris Creek. Direct contact with buried waste and ingestion of
contaminated groundwater could occur if future residential development were
allowed on-site.
Alternative 2 - Site Restrictions
Alternative 2 consists of Site access restrictions and a monitoring program,.
(Figure 16). It would reduce the public health risks by controlling access
to on-site contaminants and by monitoring contaminant migration in
groundwater.
-------
2 WELLS IN
CLUSTER
3 WELLS IN
CLUSTER
2 WELLS IN
CLUSTER
LEGEND
APPROXIMATE LANDFILL BOUNDARY
• EXISTING MONITORING WELLS
• NEW MONITORING WELLS
<— SITE FENCE
DEED RESTRICTIONS ON
PROPERTY USE
FIGURE 16
ALTERNATIVE 2
SITE RESTRICTIONS
MASON COUNTY LANDFILL FS
-------
22.
Access restrictions would, consist of a Site fence, warning signs, and deed
and zoning restrictions on property use. A six: foot high fence 4,800 feet
long, with locking gates, would be installed on or near the property
boundary. Alternatives to the site fence will be considered if they are
determined to adequately protect the landfill cap integrity and keep
trespassers away fron the area of the gas vents. Signs would be posted to.
warn, intruders of the health hazard. Deed restrictions would prohibit
future Site development and the installation of water supply wells on the
Site.
The monitoring program would consist of periodic sampling and analysis of 20
monitoring wells. Four new monitoring wells would be installed along Inman
Road to provide additional, information about the vertical and horizontal
migration of contaminants. Groundwater would be analyzed annually for
Target Compound List volatile organic compounds and. semiannually for typical
landfill monitoring parameters such as pH, specific conductivity, total
dissolved solids, total organic carbon, total organic halide, iron,
chloride, nitrate, and sulfate.
Performance and Reliability - Alternative 2 does not have processes or
equipment that might fail and the reliability of its components has been.
demonstrated. It would prevent direct public contact with buried waste,
landfill gases and contaminated sediment and surface soil. In. addition, it
would track and document the nature and extent of contaminant migration.
Changes in deed restrictions would be unlikely because the property is owned
by the Mason County DPW. Groundwater use restrictions on privately owned
property downgradient of the landfill would, be difficult to enforce.
Currently such restrictions are not needed as no residential wells are
contaminated at this time; groundwater monitoring would provide warning if
contaminant levels increased in the future. Msnitoring requires semi-annual
visits to the Site to collect samples and continued sample management
efforts to document water quality. Future actions could be implemented as
appropriate.
The Site fence and warning signs would prevent human contact with gas vent
emissions and contaminated surface soils or sediments. They would also help
protect the integrity of the landfill cap by limiting vehicle access. The
fence would, require routine maintenance for a prolonged useful life.
Implementation - Alternative 2 could be readily implemented. The four new
monitoring wells and Site fence could be easily installed by local
contractors. Construction of the Site fence would require some clearing of
trees and shrubs, and a survey would be needed to define the property
boundaries. It appears that some of the landfill is outside the property
boundary.
Alternative 2 would not pose unusual or high levels of risk to workers or
the public during implementation. Installation of the fence should not
disturb any buried wastes and the wells would be installed in areas of low
contaminant levels. Sampling team members for the monitoring program could
be exposed to volatile organic compounds for the life of the action, so well
-------
23
construction and sampling work should proceed under Level D health and
safety protection. Air monitoring during sampling activities would ensure
that exposure limits are not exceeded.
Alternative 3 - Containment (Surface Controls)
Alternative 3 consists of surface control measures as well as the Site
restrictions associated with Alternative 2 (Figure 17). It would, reduce
public health, and environmental risks by restricting Site' access, by
monitoring contaminant migration in groundwater, and by reducing the
leachate volume and associated groundwater contamination.
Surface controls would consist of clearing vegetation and regrading the
Site. Approximately 18,000 cubic yards of imported clay would be needed to
fill Site depressions, such as the ponded area, to increase the cap
thickness to at least 2 feet and to establish a three to five percent grade.
Approximately 9,000 cubic yards of imported soil would be needed for a six
inch thick layer of topsoil to support vegetation. Ihe existing drainage
structures (berms, area drains, and buried pipelines) would be incorporated
into the final grading plan and upgraded as necessary. Erosion control mats
would be placed on the steep side slopes north of the landfill to help
establish vegetation, and erosion gullies would be filled and reseeded. ;
Performance and Reliability - The components of Alternative 3 are
demonstrated and reliable. Surface controls would reduce the amount of
water percolating through the landfill contents by eliminating cracks and
ponded areas, increasing the minimum surface slope to five percent,
increasing the soil moisture storage capacity, and increasing the
evapotranspiration rate. Based on water balance calculations (Appendix A of
the FS), the percolation rate and, thus, the volume of generated leachate
would be reduced about fifty percent.
Periodic inspection and. maintenance of the landfill cap is necessary for
continued effectiveness at reducing water infiltration. Moderate to high
settlements are expected at the Site, considering the nature of the landfill
contents (mainly. municipal garbage and trash) and settlements that have
already occurred. Maintenance would consist of refilling and reseeding
areas of subsidence and erosion. Replacement of the cap should not be
necessary if proper maintenance procedures are employed throughout the life
of the remedial action.
Implementation - Alternative 3 could be implemented using routine
construction methods and equipment. Top soil, clay, and sand are available
within ten miles of the Site, and other necessary materials are commonly
available. A topographical survey would be needed to design a Site grading
plan. The 15 gas vents would probably be destroyed and have to be replaced.
Incorporating all existing drainage structures may be difficult, so some
area drains and buried pipeline may be needed.
fcforkers on the Site during regrading and gas vent replacement may be exposed
to buried wastes. Regrading is not intended to disturb, the underlying
landfill contents; Level D protection (minimum worker protective clothing)
-------
LEGEND
APPROXIMATE LANDFILL BOUNDARY
EROSION CONTROL
SURFACE CONTROLS OR SOI L-CLAY CAP
NOTE: Alternitivts 3 and 4 includt all jits r*itriction
options snown in Figurt 5-3.
FIGURE 17
ALTERNATIVES 3 AND 4
CONTAINMENT
MASON COUNTY LANDFILL FS
-------
24
would be expected, for this activity. Installation of gas vents would
require drilling through the landfill contents; Level c (air purifying
respirator required) protection may be needed for a portion of the work.
Sane short-term safety-risks to the public would result from increased truck
traffic in the area while soil is hauled to the Site. Dust levels could
increase during the- earthwork activities, but water sprayed on dry soil
would limit the amount, of dust generated. Total suspended particles would
be monitored daily during earthwork activities to ensure compliance with
appropriate ambient air regulations. Erosion of loose soil along Iris Creek
could be prevented by use of plastic covers over bare soil or temporary
dams, ditches, or fences.
Alternative 4 - Containment (Soil-Clay Cap)
Alternative 4 differs from Alternative 3 in that a soil-clay cap would be
installed instead of surface controls. Alternative 4 also includes the Site
restriction measures of Alternative 2. The components (see Figure 17)
consist of property use restrictions, a Site fence, groundwater monitoring,
and a soil-clay cap, all of which would reduce risk to public health or the
environment.
Installation, of the soil-clay cap (see Figure 14) would involve removing
vegetation, regrading, and placing a clay layer. An estimated 18,000 cubic
yards of clay (the same quantity for Alternative 3) would be needed to
increase the cap thickness to at least 2 feet. Approximately 28,000 cubic
yards of sand would be needed for an 18-inch drainage layer just above the
clay barrier, and perforated drain pipes would be installed to remove water
fromi the cap. The drain pipes would route the water to storm drains that
discharge downhill from the landfill. The existing stream drains could
possibly be incorporated into the drainage systan. About 19,000 cubic yards
of fill and 9,300 cubic yards of topsoil would be placed above the drainage
layer to provide frost protection and soil moisture storage. A geotextile
filter between the fill and sand would prevent the drains from clogging.
Performance and Reliability - The components of Alternative 4 are
demonstrated and reliable. The soil-clay would reduce percolation through
the landfill contents by providing a barrier to pievait infiltration of
water and a drainage layer to remove, water that might accumulate on the'
clay. Based on water balance calculations (Appendix A in the FS), the
percolation, rate would be reduced ninety percent from current Site
conditions. This assumes that the compacted clay barrier has a hydraulic
conductivity of 1 x 10"7 cm/s.
Inspection and maintenance of the soil-clay cap would be similar to that for
the surface controls. Since the cap must remain nearly impermeable to be
effective, repair may involve removing the upper layers to reach the clay
barrier. Settlements could eventually eliminate the slopes needed for the
drainage layer to remove water from the clay. To account -for periodic
repairs, it is assumed that annual maintenance for the soil-clay cap would
be needed for the 30-year design life.
-------
25
Implementation - Alternative- 4 would be- more difficult and take more time to
implement than Alternative 3. Additional attention to details during design
and construction would be required for the individual components of the
soil-clay clap to function properly. Potential problems include leakage of
water through the clay barrier at gas vent locations, surface infiltration
collection details, and construction on the steep side slopes. Also, a
potential problem, would be the continued subsidence of the landfill and its
effects on. drainage systems, such as perforated pipes. Protection of
workers and nearby residents during construction would be similar to that
for Alternative 3.
Alternative 5 - Groundwater Collection and Treatment
Description - Alternative 5 consists of the components described in
Alternative 4 with, the addition of a groundwater collection system and on-
site treatment plant (Figure 18). Alternative 5 would protect human health
and the environment by preventing contaminated groundwater from migrating
off the Site. Contaminant levels in the groundwater contaminant plume north
of the landfill would be reduced below maximum contaminant levels, and the
water discharged after treatment would meet ambient water quality criteria.
Ten extraction wells spaced 200 feet apart and screened in the upper aq JLfer
would be sufficient to intercept the contaminant plume (see Appendix B- of
the FS). Each well would have a discharge control valve to ensure adequate
drawdown of the aquifer. A buried header pipeline would route the pumped
groundwater to Babbin Rand for discharge. Discharge estimates range from
35,000 to 500,000 gpd; the average estimated discharge is 160,000 gpd. The
groundwater treatment system described herein was based upon the average
discharge and flow weighted, maximum, contaminant concentrations (see Appendix
C of the FS).
Groundwater treatment would consist of flow equalization and mixing in
Babbin Pond and treatment by precipitation (with associated settling and
sludge dewatering) followed by granular activated carbon (GAC) adsorption.
The precipitation and GAC units would be housed inside a building-
constructed near Babbin Pond. Babbin Pond would be enlarged from its
220,000 gallon capacity to 320,000 gallons (2-day storage volume at the
average estimated collection rate) and lined with an impermeable double
membrane system. A leak detection system for the basin would be installed
as required by RCRA. An aerator would be installed in the pond to mix and
aerate the water. This will help reduce algae growth in the summer and
prevent' ice formation in the winter. Water from the pond would be pumped to
a precipitation unit for treatment prior to GAC adsorption. The pH would be
controlled within the precipitation system. Sludges that accumulate would
be collected, solidified, and disposed of at an off-site RCRA landfill.
Water would then be pumped from the precipitation unit to two 10,000 pound
GAC columns connected in series. After treatment, the water would be
discharged by pipeline to Iris Creek.
Effectiveness and Reliability - Alternative 5 would effectively reduce
contaminant mobility by collection and treatment of the grounoVater.
Toxicity would not be reduced because hazardous materials would be
-------
EQUALIZATION POND
WITH AERATOR
"«- 3
-------
26
concentrated in sludges and. spent carton. However, risks at the Site caused
by contaminants in the groundwater would be reduced because the residuals
would be hauled to a RCEA facility.
The ^collection and treatment system has demonstrated reliable performance.
Hie pumping system would require routine inspections, but maintenance would
be routine. Pumps would require servicing every few years, and the
treatment plant would require a full-time operator (8 hours per day). Many
of the components would require eventual replacement (e.g.,. storage tanks
and pumps), and activated carbon, alum, anionic polymer, and soda ash would
have to be purchased periodically.
Hie discharged water and the contaminant plume would be monitored throughout
the life of the action to measure compliance with state and federal
regulations. Discharge parameters would include continuous monitoring for
dissolved oxygen and pH and bimonthly analysis for hazardous substances as
required by the NPDES permit.
Implementation - Alternative 5 could be implemented with difficulty
associated with both collection and treatment. Groundwater collection would
be complicated by the hydrogeology at the Site and poor access to well
locations. Part of the well alignment would go outside the property lines,
and additional property would need to be purchased or permission granted by
the property owner for installation. Pumping could adversely affect nearby
residential wells; however, the effect should be minimal because the
residential wells are either greater than 400 feet from the extraction wells
or are screened in the lower aquifer.
Rabbin Pond would need a double liner with a leak detection system. The
area would have to be dewatered during construction of the liner and the
water hauled off-site for treatment. The dewatering- system, would be left in
place in case of emergency repair to the liner. Pump tests would be
performed for each well installation to determine the actual cones of
depression and, thus, adequate well spacing. Water generated from the pump
tests would also need to be contained and named off-site for treatment.
After the extraction and collection system is installed, the actual.
contaminant loadings to the treatment system, will be determined; pilot
testing would determine the necessary treatment plant components, holding
times, and rates of chemical addition. Ine groundwater contaminant plume
might be diluted during extraction, but it was conservatively assumed that
the maximum, detected contaminant levels could be collected and the treatment
system was sized accordingly for this study. Ine components of the
treatment system could be purchased complete from various vendors. Several
mechanical parts would require routine maintenance, and the treatment
process must be carefully monitored to prevent breakthrough. An automatic
alarm system would be installed for after-hour plant emergencies. The plant
would produce about 640 gallons of sludge at thirty percent solids per day.
The sludge would require periodic transport and disposal at a RCRA facility.
Health and safety risks during implementation would, include potential direct
contact with contaminated water during well installation and dewatering
-------
27
activities associated with installation of the pond liner. However,
contaminant levels are low and Level D protection is expected to be
adequate. There are some health risks associated with sludge handling and
carbon regeneration, and trained personnel would be required. Risks to the
public would consist of transport of contaminated water and sludge on public
highways.
Alternative 6 - Removal, Treatment, and Disposal
Alternative 6 consists of the components of Alternative 5 with the addition
of the removal and treatment of landfill contents (Figure 19). Only
removal, treatment, and disposal of landfill contents is described below. A
RCRA-type landfill facility would be constructed on-site to contain the
landfill contents. Alternative 6 would reduce the mobility of contaminants
through treatment (fixation) and contaminant.
An estimated 140,000 cubic yards of material would be excavated and
segregated for treatment. Materials would be sorted according to waste type
(i.e., metal, paper, plastics) and size. Preprocessing would consist of
shredding or breaking the materials to sizes that could readily be mixed
with the appropriate fixing agents. All excavated material would be-
temporarily stockpiled during preprocessing in a specially constructed!
building with a leachate collection system. Waste materials and fixing
agents could be mixed in a pit or directly in. the newly constructed RCRA
facility using equipment such as front-end loaders, bulldozers, and
backhoes.
It is difficult to estimate accurately the size of the on-site RCRA-type-
facility necessary to store hazardous materials because of inaccuracies
associated with the landfill volume estimate, the increase in volume caused
by the addition of fixing agents, and the final depth of fill in the new
facility. Based on the estimated 140,000 cubic yards of material and an
assumed volume increase of ten percent, the RCRA-type facility would need to
contain a volume of roughly 150,000 cubic yards. Assuming that wastes could
be placed to an average thickness of twelve feet, an area of about eight
acres would be needed. Quantities of earthwork and other materials needed
to construct the RCRA-type facility are based on the cross-sectional
dimensions shown in Figure 15. ' ' "'
Effectiveness and Reliability - Alternative 6 would effectively reduce
contaminant mobility at the Site, but would not reduce the toxicity and
volume of contaminants. Groundwater monitoring would be necessary to ensure
that contaminants do not leak through the liner of the landfill. The
effectiveness of the facility would depend upon continued maintenance of the
cap and upon collection, treatment, and disposal of leachate.
By controlling the contaminant source, contaminant loading of the
groundwater would be virtually eliminated. At some future time contaminant
levels in the groundwater contaminant plume are expected to be reduced below
levels that would cause public health or environmental risks. Since it is
not possible to predict the time period necessary for this to occur,
-------
EQUALIZATION POND
WITH AERATOR
LEGEND
APPROXIMATE LANDFILL BOUNDARY
EXTRACTION WELLS AND HEADER
INFLUENT AND DISCHARGE PIPELINE
EXCAVATED AREA
RCRA-TYPE LANDFILL
NOTE: Excavation limits art tha approximate
landfill boundary. Altarnativa 6 include!
all tita restriction options shown in Figure 5-3.
FIGURE 19
ALTERNATIVE 6
REMOVAL. TREATMENT, AND
DISPOSAL
MASON COUNTY LANDFILL FS
-------
28
groundwater collection and treatment is assumed for the full 30-year life of
the action.
Implementation - Alternative 6 would be difficult to implement. Wbrlc
schedules would require constant adjustment depending on the type of
materials encountered. Hazardous or toxic materials have to be sorted from
nonhazardous and nontoxic materials prior to treatment. Size reduction and
several different treatment mixtures would, probably be needed for adequate
fixation. The construction sequence would require excavating an area and
stockpiling materials until construction of the on-site RCRA. landfill cell
was completed. Large volumes of material would have to be stockpiled, and
protected fron wind, and water erosion.
Workers would be exposed to health and safety risks for the length of the
action, but Levels B and C protection would be used to protect worker
health. Public health and environmental risks could occur from airborne
contaminants during excavation or from wind and water erosion of stockpiled
wastes. An air monitoring programi would be implemented during any waste
handling activities to detect emissions of volatile organic compounds or
particles.
VIII.. SIMftRY OF COMRVRAIIvE ANALYSIS CF ALT£ra»HvES
This section compares the six remaining alternatives using- the following
nine criteria:
Short-Tenni Effectiveness
* Protection during remedial actions.
* Time until protection is achieved.
Long-Term. Effectiveness
* Magnitude of residual risk.
* Long-term controls.
Reduction of Toxicity, ftobility, and Volume
* Treatment process used, and materials treated.
* Amount of hazardous materials destroyed or treated.
* Type and quantity of'residua is remaining after treatment.
* Degree of expected reductions in toxicity, nobility, and
volume.
* Degree to which treatment is irreversible.
Implementation
* Technical feasibility.
* Availability of necessary services and. materials.
* Administrative feasibility.
Cost
* Direct capital costs.
* Indirect capital costs.
* Operation and maintenance costs.
* Total present worth.
-------
29
Compliance with ARARs
* Compliance with, contaminant-specific ARARs.
* Compliance with action-specific ARARs.
* Compliance with location-specific ARARs.
Overall Protection
* How alternative provides protection of human health and the
environment.
State Acceptance
* Aspects of the alternative that the state supports.
* Aspects of the alternative about which the state has
reservations.
* Aspects of the alternative that the state strongly opposes.
Conirunity Acceptance
* Aspects of the alternative that the community supports.
* Aspects of the alternative about which the community has
reservations.
* Aspects of the alternative that the community strongly opposes.
Seven of the nine evaluation criteria (excluding state acceptance and
community acceptance) are sunmarized in Table 6. State acceptance and
connunity acceptance are discussed later in this ROD. Specific ARARs that
apply or nay apply to each alternative are listed in Table 7.
Costs for each alternative are detailed within the FS report and are
smmarized in Table 8.
IX. m'lH «KM1 PLATS AND DOCOMENIATTCN OF SK2HFICA11HP CHANGES [SECHCN 117 (b) ]
The U.S. EPA's Proposed Plan was released for public comment from August 8
through August 31, 1988. In the Proposed Plan, the U.S. EPA. stated that the
remedial action at this Site will be divided into two separate operable
units; one dealing with landfill contents and the other with groundwater.
The Proposed Plan announced Alternative 4 (containment-soil/clay cap), which
also includes the Site restrictions of Alternative 2, as the U.S. EPA's
preferred remedial action alternative for the landfill contents operable
unit. Remedial action on the groundwater operable unit was deferred until
the effectiveness on the landfill contents remedial action could be
measured.
After the Public Comment Period and comments from the Coimunity were
received, no significant changes were made to the U.S. EPA's preferred
alternative for the landfill contents operable unit (Alternative 4) and the
deferring of the selection of a remedy for the groundwater operable unit.
-------
EVALUATION
FACTOR
ALTERNATIVE 1
NO ACTION
ALTERNATIVE I
SITE RESTRICTIONS
ALTERNATIVE J
CONTAINMENT
(SURFACE CONTROLS)
ALTERNATIVE 4
CONTAINMENT
(SOIL-CLAY CAP)
ALTERNATIVE 1
OROUNDWATER COLLECTION
AND TREATMENT
ALTERNATIVE •
REMOVAL. TREATMENT
AND DISPOSAL
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REDUCTION OF
TOXICITY. MOBILITY
AND VOLUME
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TABLE S . (PAGE MMI
EVALUATION AN^^VAniSON
OF REMEDIAL All^RIIVtS
MAMNCOUNIV lANO'al '•
-------
{VALUATION
FACTOR
ALTERNATIVE I
NO ACTION
ALTERNATIVE I
SITE RESTRICTIONS
ALTERNATIVE 1
CONTAINMENT
(SURFACE CONTROLS)
ALTERNATIVE 4
CONTAINMENT
(SOIL-CLAY CAP)
ALTERNATIVE f
CROUNOWATER COLLECTION
AND TREATMENT
ALTERNATIVE •
REMOVAL. TREATMENT
AND DISPOSAL
SHORT-TERM
EFFECTIVENESS
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EFFECTIVENESS
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TABLtt (PAGE I OF 31
{VALUATION AND COMPARISON
Of REMEDIAL ALTERNATIVES
UAIOXroUNI* LA^OIUL II
-------
•VALUATION
FACTOR
ALTIKNATlVe I
NO ACTION
ALTERNATIVE I
SIT! RESTRICTIONS
ALTERNATIVE I
CONTAINMENT
(SURFACE CONTROLS)
ALTERNATIVE 4
CONTAINMENT
(SOU CLAY CAP)
ALTERNATIVE •
OROUNOWATER COLLECTION
AND TREATMENT
ALTERNATIVE •
REMOVAL. TREATMENT
AND DISPOSAL
OVERALL PROTECTION
OF HUMAN HEALTH AND
THE ENVIRONMENT
IMCIUM
4 i
C4V4W1
• Mi bMk.
MvMlh* 1 M* Mtl
11* fOIMIMM
«•«•.
Mn ol Ml* t
•I
m M
-------
Table 7 (Page 1 of 3)
ARARs FOR THE MASON COUNTV LANDFILL
Regulation
FEDERAL
Clean Air Act,
Section 101
40 CFR 52
40 CFR 50
Clean Water Act,
Section 208
40 CFR 122
40 CFR 125
40 CFR 131
40 CFR 136
40 CFR 257
40 CFR 261
40 CFR 262
40 CFR 263
40 CFR 264.1
through .117(C)
40 CFR 264.191
through .198
Requirement
Implementation of regional air
pollution control programs.
Rules for implementation of
regional air quality plan.
Air quality standards.
Actions consistent with regional
water quality management pro-
gran.
NPDES pernlt regulations.
Criteria for NPDES permit.
Enforcement jurisdiction over
discharges granted to states.
Adherenece to sampling
procedures.
Standards for solid waste dis-
posal facility; management
delegated to states.
Definition and Identification
of hazardous waste.
Regulations for generators of
hazardous waste.
Regulations for transport of
hazardous waste.
Regulations for closure of a
hazardous waste site.
Regulations for tank storage
of hazardous waste.
Regulated Action
or Condition
Emissions during excavation. Possibly
gas vent emissions.
Emissions during excavation. Possibly
gas vent emissions.
Emissions during excavation. Possibly
gas vent emissions.
Discharges to Iris Creek.
Discharges to Iris Creek.
Discharges to Iris Creek.
Discharges to Iris Creek.
Discharges to Iris Creek.
U.S. EPA to determine If Subtitle D
landfill closure is appropriate.
Excavated materials and groundwater
treatment residuals.
Groundwater treatment residuals hauled
offslte.
Groundwater treatment residuals hauled
offslte.
U.S. EPA to determine If Subtitle C
closure regulations are appropriate.
Groundwater treatment system tanks.
Alternative
1 2 3 4
t
9
X X X X
X X XX
X X X X
X X X X
X X X X
5
X
X
X
X
X
X
X
X
X
X
X
X
X
X
6
X
X
X
X
X
X
X
X
X
X
X
X
X
X
-------
Table 7 (Page 2 of 3)
Regulation
40 CFR 264.301
through .314
40 CFR 264
Subpart X
40 CFR 268
Subpsrts C and D
40 CFR 403
40 CFR 141
Executive Order
12372,
40 CFR 29
Executive Ordera
11988 and 11990,
40 CFR 6,
Subpart A
Fish and Wildlife
Coordination
Act
STATE
ACT 348
ACT 315
ACT 641
ACT 64,
Parts 2 and 3
Requirement
Riilos for construction, main-
tenance and closure of a
hazardous waste landfill
Standard* for environmental
performance of miscellaneous
treatment units.
Land-banned waste materials.
Pretreatment standards for
discharge to local POTW.
Establishes maximum contami-
nant levels for drinking water
quality.
Requires state and'local
coordination and review of
EPA-asslsted projects.
Avoids adverse affects to
flood plain or wetlands and
evaluates potential impact* to
those areas.
Protects fish and wildlife
when natural stream ia •
modified.
Regulates air emissions and
requires monitoring of air.
Regulates permitting, construc-
tion, and abandonment of
wells.
Regulatea the disposal of
nonhazardous waate.
Requirements for identifica-
tion, recordkeeping, and man-
agement of hazardous waste.
Regulated Action
or Condition
i
Construction and closure of a
RCRA type landfill
Physical/chemical treatment.
Would apply to certain solvent-containing
wastes if present in landfill contents.
Discharges to POTW after installation of
extraction wells but before Installation
of onslte groundwater treatment plant.
Croundwater at the site.
Mason County Landfill ia a CERCLA site.
Croundwater extraction and collection
will probably "dry up" the marshy area
near Babbln Pond.
Discharges to Irla Creek.
Handling and treatment of landfill
contenta; gaa vent emissions.
Monitoring wells onslte and near site.
Croundwater extraction wells.
May be appropriate for landfill closure.
Generated groundwater treatment residuals
and excavated landfill contents.
Alternative
tr
x
jr
X
X
X
-------
Table 7 (Page 3 of 3)
Regulation Requirement
ACT 64, Regulations for construction
Part 5 and licensing a new hazardous
waste facility.
ACT 64, Specifies technical standards
Part 6 for locating operating and
closing a hazardous waste
facility.
ACT 136 Requirements for transport of
ACT 64, liquid or solid waste offslte.
Part 4
ACT 347, Requires a soil erosion and
Rule 1704 sedimentation plan for earth
changes within 500 feet of a
laXe or stream.
ACT 245, Rules for reporting discharges
Part 9 to state waters.
ACT 245, Rules for NPDES permit.
Part 21
ACT 98 . Supervision and control of
sewerage systems.
ACT 203 Regulates activities that
affect wetland areas.
ACT 346, Permit for construction In
Section 3 "bottom land."
Regulated Action
or Condition
Onslte RCRArtype landfill.
Onslte RCRA-type landfill and containers
or tanks used for treatment may be
appropriate for landfill closure.
Hauling contaminated groundwater to local
POTH during Installation of groundwater
collection and treatment system. Trans-
port of groundwater treatment residuals.
Erosion control measures along north
slope of landfill and construction
activities for groundwater collection and
treatment systems.
Discharges from groundwater treatment
plant.
Discharges from groundwater treatment
plant.
Construction and operation of groundwater
treatment plant.
Construction and operation of groundwater
collection system; discharges to Iris
Creek.
Burled pipeline for groundwater
collection and discharge.
Alternative
5 6
X
X
X
X
X
X
X
X
X
"X" Indicates that regulation is applicable or relevant and appropriate.
GLT806/1
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Table 8
COST ESTIMATE SUMMARY
Description
Sic* Fence
MontcorIng Well Installation
Surf«ce Controls
Soil-Clay Cap
Croundvater Collection
Crouadvater treataeat
Excavation
Onalte Fixation
Onsite ROU Landfill
Allowances
Other Coats
Direct Capital Cost
Present Worth of 04M Costs
Alternative
2
S 67,000
21,000
0
0
0
0
0 "
0
0
11,000
67.000
$166,000
530.000
3
$ 67,000
21,000
345,000
0
0
0
0
0
0
52,000
322.000
$807,000
765.000
4
$ 67,000
21,000
0
868,000
0
0
0
0
0
115,000
687.000
$1,758,000
1.070,000
5
$ 67,000
21,000
0
868,000
184,000
937,000
0
0
0
353,000
1.840,000
$4,270,000
7.970.000
6
$ 67,000
21,000
0
0
184,000
937,000
4,026,000
8,749,000
2,711,000
2,838,000
14.668.000
$34,201,000
9j 100, 000
Total Present Worth Estimate $700,000 $1,600,000 $2,800,000 $12,000,000 $43,000,000
Allowances consist of aobilization/deaobilization and a field
detail allowance. See Appendix D for detailed breakdown.
Other costs consist of contingencies for bid and scope iteas aad
allowances for adainistrative services, engineering design, and
services during construction. See Appendix D for detailed breakdown.
Present worth estimates assume a discount rate of 5 percent annually
over a period of 30 years.
Cost estimate is order-of-aagnitude level with expected accuracy of
+50 percent to -30 percent. Total present worth estimate is
rounded to two significant figures.
OLT626/81
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30
X. SELECTED RfcMJJJT AND SIKTUKKT DE3ERHEBVEICM5
A. Lapri-Fiii Contents Operable Unit.
Delected remedy for tJbe landfill contents operable unit is Alternative 4
wnich innjiyto? the fmt-j>-iniMii_ of the- landfill contents by means of a
soil/clay RCRA subtitle C compliant cap. Site restrictions and groundwater
monitoring.
Alternative 4 is protective of human health and the environment, attains or
defers applicable or relevant and appropriate requirements promulgated under
Federal and State environmental laws and is cost effective. Alternative 4
is not the final remedial action for the Site but' is consistent with the
final remedy. Ine final remedy at the Site will include the remedial action
alternative from the landfill contents operable unit (Alternative 4) and the-
remedial alternative chosen after the groundwater operable unit is
completed.
1. Protection of Human Health and the Environment.
Alternative 4 provides protection of human health and the environment
through the use of containment of landfill contents and institutional
controls such as Site access restrictions. Protectiveness is achieved with.
the upgrading of the present cap to a RCRA compliant, subtitle C, soil/clay
cap. Ine cap is a reliable method to alleviate the direct contact threat
from the landfill contents. 3ne RCRA compliant cap is estimated to reduce
leachate generation by ninety percent, which, in turn should lower the amount
of contamination reaching the groundwater. Also, by reducing the
concentrations of contaminants reaching the groundwater, less contamination
will reach the surface water bodies near the Site (the wetlands, Babbin Pond
and Iris Creek) .
Since untreated wastes will remain within the landfill, the groundwater will
continue to be monitored to ensure the protectiveness of the selected
operable unit remedy. Hie results of this monitoring will also aid in
determining the remedy for the groundwater operable unit.
The institutional controls implemented from. Alternative 2 will aid in
achieving the protectiveness to human health and the environment. Tne Site
access restrictions (Site fence and warning signs) will reduce public health
risks by preventing public contact with buried waste, landfill gases,
contaminated sediment and surface soil. The Site access restrictions win
also help protect the integrity of the landfill cap by limiting vehicle
access. The continued groundwater monitoring will track and document the
nature and extent of contamination migration. Deed restrictions will
prohibit future Site development and the installation of water supply wells
on and near the Site.
No treatment technologies are being applied to reduce toxicity, mobility or
volume of hazardous waste with the implementation of Alternative 4, so the
permanence of this interim remedy depends on the maintaining of the
integrity of the upgraded cap. Also, with the installation of the RCRA
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31
subtitle C compliant soil/clay cap, leachate production is anticipated to be
reduced by ninety percent, thereby reducing the volume of contaminants
reaching groundwater and indirectly reducing the mobility and toxicity of
contamination in the groundwater.
2. Attainment of Applicable or Relevant and Appropriate
Requirements of Environmental Laws.
Alternative 4 will be designed to meet all the applicable, or 'relevant and
appropriate requirements (ARARs) of Federal and more stringent State
environmental laws. ARARs, including maximum, containment levels (MZLs) in
groundwater, may be met with the implementation of Alternative 4, but the
MZLs will not be addressed until the conclusion of the groundwater operable
unit. Table 7 lists the ARARs that apply to each of the alternatives and
the following discussion provides the details of the ARARs that will be met
by Alternative 4.
a. Feder^ 1; pgs,ource Conservation and Recovery Act
RCRA. closure and. post-closure requirements for landfills with hazardous
wastes are outlined in 40 CFR subpart G. Section 264.310 of RCRA, subpart
N, specifies the performance-based requirements for a cover at final J
landfill closure. Tne cover in Alternative 4 will be a cap- as prescribed in
RCRA guidance and will comply with RCRA regulations. Ine cap will minimize
migration of liquid, through the landfill, function with minimum-maintenance,
promote drainage, minimize erosion, accommodate settling, and be less than
or equal to the permeability of natural subsoils present.
After closure is completed, the substantive monitoring and maintenance post-
closure requirements contained in Section 264.117 through 264.120 of Subpart
G will be conducted. The facility will be closed according to the standards
in Subpart G, Section 264.Ill-closure performance standards. After the
closure activities have concluded, a survey plat, as prescribed in Subpart
G, Section 264.116, indicating location and dimensions of the disposal area
will be submitted to the local zoning authority, or to the authority with
jurisdiction over local land use, and the Regional Administrator and the
Michigan state Director. , •&.
- • *f
b. State! htezfliT'itous Waste Management. Act (Act 64)
To the extent that Act 64 is more stringent than the Federal RCRA
regulation, Act 64 will be followed.
Relative to landfill closure provisions, Act 64, Rule 619 specifies the
closure standards, including a minimura cover requirement, and requirements
for venting, which will be followed.
c. Federal: Clean Air Act
The Clean Air Act (CAA.) identifies and. regulates pollutants that could be
released during earth-rroving activities associated with landfill regrading
and cap installation. CAA. Section 109 outlines the criteria pollutants for
-------
32.
which National Ambient Air Quality Standards have been established. The CAA.
is an ARAR and the regulation standards will be complied with during the
implementation of Alternative 4.
d. State; Air Pollution Act (Act 348)
Under Act 348 Rule 901, the Michigan Air Quality Division exercises its
authority to ensure that a person does not cause or permit the emission of
an air contaminant in quantities that will cause "injurious effects to human
health or safety, animal life, plant life of significant economic value or
property" or "unreasonable interference with the comfortable enjoyment of
life and property. " Also , Rules 371 and 373 address fugitive dust programs
and. control methods for emissions of dust from a variety of sources
including haul trucks, roads and stockpiles of materials.
e. Federa.il ; foiTT^pationrn safety and H^gJth Administration Act
(OSHA.)
The selected remedial action contractor must develop and implement a health
and. safety program for its workers if such program does not already exist.
All on-site workers must meet the minimum training and. medical monitoring
requirements outlined in 40 CFR 1910.
f6 Coordination Act
Executive Carders 11988 and 11990 and the Fish and Wildlife Coordination Act
pertain to the protection of flood plains and wetlands and protect fish and
wildlife if the wetlands or natural streams are modified. The provisions of
these Orders and Act will be implemented if during the design phase of the
remedial action, they are determined to be applicable or relevant and
appropriate.
g. Stater Michigan Water Resources Act (Act 245)
Act 245, Part 21 requires that any remedial action in which site runoff
would be channeled directly to a surface water body via a ditch, culvert,;
storm sewer, or other means shall be governed by this Act. The provisions
of this Act will be met at this site to the extent that it applies as
determined by the MDNR after the design stage is completed.
h. State! Mineral Well Act (Act 315)
Act 315 and the Administrative Rules require that test wells be permitted,
constructed property, recorded, and. properly plugged upon abandonment. This
Act is an ARAR and treatment of all test wells will be dictated by it.
i. State; Soil Erosion and Sediment at ion Control Act (Act 347)
Under Rule 1704 of this Act, a soil erosion control and sedimentation plan
is required for any earth change within 500 feet of a lake or stream. This
Act and its Rule call for soil erosion and sedimentation control procedures
-------
33
and. measures to minimize such erosion and sedimentation. Hie erosion
control measures along the north slope of the landfill will meet the
requirements of this Act.
j. Other Federal and State ARARs
Since Alternative 4 is an interim/ remedy, directly addressing only the
landfill contents operable unit, ARARs concerning groundwater, such as 40
CFR 141, regarding MZLs, and ARARs concerning the surface waters, such as
the Clean Water Act are being deferred until a remedy is selected for the
groundwater operable unit. Alternative 4 may indirectly address these other
ARAR concerns but the degree cannot be determined at this time.
All Federal and State ARARs will be satisfied, by the final Site remedial
action which will be selected after the groundwater operable unit is
complete.
3. Cost-Effectiveness.
Alternative 4 affords a high degree of effectiveness by providing protection
against direct contact threats and the threat of releases to the
groundwater. The cost of Alternative 4 is $1.8 million with a present
worth, including operation and. maintenance, of $2.8 million over thirty
years. Alternative 4 is less costly to implement and maintain than
Alternatives 5 and 6, and provides protection, for human health and the
environment. The additional costs of Alternatives 5 and 6 can not be
justified at this time since Alternative 4 may address the groundwater
concerns. Additional costs may be incurred depending upon the outcome of
further studies at the site involving the groundwater operable unit. By
providing a greater reduction in leachate generation than Alternative 3,
Alternative 4 may reduce future costs associated with groundwater
remediation more than Alternative 3.
4. Utilization of Permanent Solutions, Alternative Treatment
Technologies to the Maximum Extent Practicable, and Preference
for Treatment as a Principal Element.
Although the selected remedy for the landfill contents operable unit will
reduce leachate generation by an estimated ninety percent, Alternative 4
does not utilize any permanent solutions or alternative treatment
technologies. Alternative 4 is considered to be an interim remedy to
address the landfill contents operable unit, one that will be consistent
with the final overall site remedy. Alternative 5 and 6 offer greater
degrees of permanence and alternative treatment technologies, but
Alternative 5 is not feasible at this time since Alternative 4 may address
the groundwater contamination concerns that would be addressed by
Alternative 5; Alternative 6 is deemed impractical because of the quantity
and heterogeneous nature of the landfill contents. Depending on the
effectiveness of Alternative 4, alternative treatment technologies may be
applied as part of the final remedy at this Site.
B» Groundwater Operahig Unit-
-------
34
TJris Record of Decision selects a remedy to address the landfill contents
operable unit; this remedy calls for the installation of an upgraded., RCRA.
compliant cap .and institutional controls. As the selected landfill contents
operable unit remedy (Alternative 4) will indirectly address groundwater
concerns, the effectiveness of the upgraded cap needs to be measured prior
to selecting a remedy to address the groundwater operable unit. Alternative
4 indicates that four additional groundwater monitoring wells will be
installed to help define the geological conditions at the Site. A. total of
twenty monitoring wells will be sampled on a semi-annual basis.
To enable a final remedy to be selected for the Site, the remedial
investigation regarding the groundwater operable unit needs to be continued
until the effectiveness of Alternative 4 can be measured. TO fully evaluate
the effectiveness of Alternative 4 and to establish enough justification to
select a remedy for the groundwater operable unit, further monitoring of the
twenty groundwater monitoring wells, as noted above, will be conducted, as
well as, the further monitoring of residential wells, gas vents, and surface
water and sediments within the wetlands, Rabbin Pond and Iris Creek. To
enable a most current baseline of groundwater contamination and site
conditions, and. to provide continued protection of human health and the
environment, the groundwater operable unit monitoring program will begin
prior to the design and construction of the RCRA. compliant cap. The
specific requirements of the continued remedial investigation for the
groundwater operable unit will be established during the design stage of the
selected landfill contents remedial action.
XL. STATE ISSUES
The Michigan Department of Natural Resources (MNR) has concurred with this
Record of Decision (ROD). This concurrence is conditional upon the
incorporation of their concerns and comments into this PCD as stated in
their September 13, 1988 letter to the U.S. EPA. (See Attachment 1)
These concerns and comments have been addressed in this ROD or will be
addressed during the design phase of the project, as noted in the letter of
September 20, 1988 from the U.s: EPA, to the M3UR (See Attachment 2).
xii. sun&Kf
Considering the various evaluation factors in SARA Section 121 (b) and the
National Contingency Plan, selecting Alternative 4 for the landfill contents
operable unit and the deferring of the selection of a remedial alternative
for the groundwater operable unit until the effectiveness of Alternative 4
can be measured, offers a cost-effective solution to the contaminant
problems at the Site. Alternative 4 either satisfies the Federal and State
ARARs or defers them until a final remedy is selected after the conclusion
of the groundwater operable unit.
Alternative 4 is an interim remedial action that is consistent with a final
remedy for this site and provides adequate protection of human health and
the environment. Another Proposed Plan and Record of Decision will be
-------
35
issued at the conclusion of the ongoing remedial investigation involving the
groundwater operable unit to announce and select a final remedy for the
Mason County Landfill.
Ine cost of Alternative 4 is $1.8 million, with a present worth, including
operation and maintenance, of $2.8 million over thirty years. The cost of a
final remedial action can not be fully determined until a remedy is chosen
to address the groundwater operable unit.
-------
ATTACHMENT 1
STATE OF MICHIGAN
JUMAL mSOUNCeS COMMISSION
THOMAS J. ANDERSON
MARLENE J. FLUHAflTY
KERRY HAMMER
6. STEWART MYERS i I
OAVIOO.PLSON__ JAMES J. BLANCHARO, Governor ' 'J'
DEPARTMENT OF NATURAL RESOURCES
STEVENS T. MASON BUILDING
8OX3002S
LANSINO. MI 4*atm ','r«
. . , , . .,, ,- -„
RAYMOND POOPORE ' .7 J "* W !4 1 JV7
-0 -* U J
David F. Hales, Director
September 13, 1988
Ms. Mary Cade
U.S. Environmental Protection Agency
Remedial and Enforcement Response Branch
SHR-li
230 South Dearborn Street
Chicago, Illinois 60604
Dear ilia. Gade:
The Draft ROD received August 17, 1988, regarding the Mason County
Laudflll site in Ludington, is conditionally acceptable. I would like to
have the following concerns and comments incorporated into the final ROD
as uhi State's response for this site.
1. The proposal to fence the entire site does not seem practical given
the limited potential for exposure to contaminants. We prefer that
alternatives to fencing such as landscape modifications or some
other reasonable alternative be considered prior to the selection of
fencing.
2. There should be institutional controls provided such as deed
restrictions or restrictive covenants to assure that land uses are
controlled.
3. Groundwater monitoring as part of the deferred groundwater operable
unit should be funded and initiated prior to design and construction
c* the RCRA compliant cap. Monitoring data should enable the
involved agencies and PRP's to better evaluate the effectiveness of
the cap by providing current background conditions at the site.
4. CTI page 25, add as a potential problem the fact that subsidence has
already caused the cap to fall. A drainage system such as perforated
pip-; would fall if the clay layer below it subsides.
Finally, the State of Michigan encourages EPA to pursue PRP involvement
by using all means available including issuing a Section 106
Administrative Order to all viable potentially responsible parties.
R1026
-------
Ms. Mary Gade
Page 2
September 13, 1988
Attached is a letter to Mr. Dan Cozza regarding the State's position
concerning the Proposed Plan received July 19, 1988. Please let me know
if you have questions.
Sincerely,
Gary B^Jfuenther, Chief
Environmental Response Division
517-373-4823
Attachment
cc: --/Mr. Dan Cozza, U.S. Environmental Protection Agency
Mr. William Bradford, Acting Chief, Remedial Action Section
Mr. Peter Ollila/Mr. Bill Herceg/Mason County Landfill file
-------
ATTACHMENT 2
^'^^\ UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
* ^^ 1 REGIONS
r * 230 SOUTH DEARBORN ST.
^ CHICAGO, ILLINOIS 60604
REPLY TO THE ATTENTION OF:
SEP 2~0 1385
Mr. Gary E. Guenther 5HS-11
Michigan Department of Natural Resources
Stevens T. Mason Bldg.
Box 30028
Lansing, Michigan 48933
RE: Mason County Landfill ROD
Dear Mr. Guenther:
Thank you for your concurrence on the Mason County Landfill Record of
Decision (ROD). It is understood that this concurrence is conditional.
upon the incorporation of your concerns and comments into the ROD, as
addressed in your letter of September 13, 1988. As this letter addresses
those concerns and indicates how your concerns have been or will be
addressed, it is assumed that your conditions of concurrence have been
met.
Below are your concerns followed by the U.S. EPA's response.
1) MDNR concern:
Alternatives to fencing the entire site should be considered.
U.S. EPA response:
The sentence, "Alternatives to the site fence will be considered
if they are determined to adequately protect the landfill cap
integrity and keep trespassers away from the area of the on-site gas
vents", has been added to the Alternative 2 (site restrictions)
description in Section VI-B of the ROD. Alternative 4 (the chosen
alternative) uses the site restrictions as described within
Alternative 2.
2) MDNR concern:
There should be institutional controls provided such as deed
restrictions or restrictive covenants to assure that land uses are
controlled.
U.S. EPA response:
Deed and zoning restrictions are mentioned in the description of
Alternative 2 within Section VI-B of the ROD. These restrictions
pertain only to site property use, while off-site property
restrictions may be necessary in the future. Because there is no
federal authority to implement deed or zoning restrictions, state and
local governments would have to be coordinated with to pursue these
options.
-------
3) MDNR concern:
Groundwater monitoring as part of the deferred groundwater operable
unit should be funded and initiated prior to design and construction
of the RCRA compliant cap. Monitoring data should enable the
involved agencies and PRPs to better evaluate the effectiveness of
the cap by providing current background conditions at the site.
U.S. EPA response:
The sentence, "To enable a most current baseline of groundwater
contamination and site conditions, and to provide continued
protection of human health ancL the environment, the groundwater
operable unit monitoring program will be initiated prior to the
design and construction of the RCRA compliant cap" has been added to
the last paragraph in Section X-B of the ROD.
4) MDNR concern:
It should be mentioned that another implementation problem associated
with Alternative 4 would be that since subsidence has caused the
present cap to fail, subsidence of the new clay cap will cause any
drainage system, such as perforated pipe, to fail.
U.S. EPA response:
This concern has been noted within the description of Alternative 4
implementation in Section VI-B of this ROD and will be reviewed
during the design phase.
5) MDNR concern:
The State of Michigan encourages EPA to pursue PRP involvement by
using all means available including issuing a Section 106
Administrative Order to all viable potentially responsible parties.
U.S. EPA response:
Special Notice Letters for RD/RA negotiations have already been sent
to six PRPs on August 24, 1988. if the negotiations are not
successful, other means of enforcment will be considered.
If you have any questions or further comments regarding this letter or
the Mason County Landfill ROD, please let me know.
Sincerely,
Mary A. Gade
Acting Associate Director
Office of Superfund
-------
-3-
cc: 0. Cozza, WMD
M. Radell, ORC
B. Herceg/P. OTIila, MDNR
-------
ATTACHMENT 3
RESPONSIVEHESS SUMMARY
MASON COUNTY LANDFILL
MASON COUNTY, MICHIGAN
The U.S. Environmental Protection Agency (U.S. EPA) has
gathered information on. the types and extent o'f
contamination found, evaluated remedial measures, and has
recommended a remedial action at the Mason County-
Landfill. As part of this process, a public meeting was
held to explain the intent of the project, to describe the
results, and to receive comments from, the public.
Public participation in Superfund projects is required in
the Superfund Amendments and Reauthorization Act of 1986
(SARA). Comments received from the pub-lie are considered
in the selection of the remedial action for the site. The
Responsiveness Summary serves two purposes: to provide the
U".S. EPA with information about community preferences and
concerns regarding the remedial alternatives and to show
members of the community how their comments were
incorporated into the decision making process. Comments
regarding information specifically contained, in the RI/FS
are not addressed in this Responsiveness Summary as this
information is contained in the reports available for
public viewing at the Ludington Library.
This document summarizes the oral comments received at the
public meeting held August 17, 1988, and the written
comments received during the public comment period August
8, 1988 to August 31, 1988. Each comment is followed by a.
letter which refers to the originator(s) of the comment.
Please refer to Appendix A for a complete list of
respondents. The Responsiveness Summary addresses concerns
in the following general areas:
1. Design concerns.
2. Implementation concerns;^
3. Environmental Impact/Risk Assessment concerns.
4. Funding concerns.
5. Property value concerns.
6. Notification period and response time concerns.
Individual comments have been summarized and grouped in
these six general areas. U.S. EPA responses follow each
comment.
-------
1. Design concerns
l.a. Comment
The north end of the landfill was exposed, at one time and
just covered over. There is no cap to upgrade, or repair.
How will that be dealt with? (see A. in Appendix A)
l.a. Response
The specifics of the cap will be examined in the design
stage of the remedial action. If there was no cap in one
section, Alternative 4 suggests the cap be a specific
uniform thickness throughout, so a new cap would be built
in that area.
1.b. Comment
Has a permeability test been done on the existing landfill
cap since the existing cap will be incorporated into the
Alternative 4 clay cap? And, if the existing clay cap does
not meet RCRA requirements, will this alter the quantity of
clay and the cost of the remedy? (E)
l.b. Response
Permeability tests were not conducted on the existing cap
during the RI/Fs. It is possible that the existing clay
may have to be reworked and that more clay than estimated
may be needed, increasing the estimated cost. These
questions will be addressed as part of the design phase.
I.e. Comment
The design of the soil/clay cap for the landfill specifies
the placement of 1.5 feet of topsoil and fill material
above the geotextile fabric. Depending upon the depth of
the frost line in the area, this depth may be insufficient
to permit the permanent establishment of soil invertebrate
populations, particularly earthworms. This in turn may
hamper the viability of a permanent vegetative cover on the
cap. It may be necessary to increase the depth of the
topsoil and fill layers so as to create a suitable
environment for the soil amending invertebrates.
A permeability rating of 10~7 cm/sec is expected of the
clay layer in the soil/clay layer, provided the clay layer
is protected from the frost and wet/dry cycles. Is the
three feet of topsoil, fill, and sand to be placed above
the clay layer sufficient protection in this area of
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Michigan? Additional material may be necessary to provide
adequate protection for the clay layer. (L)
i.e. Response
Both of these comments will be addressed, in the pre-design
and design phases of the remedial action.
l.d. Comment
The RI report indicates that surface runoff/percolation of
precipitation will be collected from the soil/clay cap and
discharged to Iris Creek. Under pristine conditions,
surface water runoff and groundwater recharge at the site
would discharge to and sustain the wetlands adjacent to
Babbin Pond. Removal of this water source, coupled with
possible future extraction of groundwater for treatment,
threatens to "dry up" the wetland area, as identified in
the FS study. One way to minimize this impact is to
redirect the collected surface runoff/percolation waters to
the wetland area rather than to Iris Creek, which is
further downgradient. Of course, this would be contingent
upon the collected water being free of contamination as
expected. (L)
l.d. Response
This will be addressed in the pre-design and design phase
of the Remedial Action. The discharge will comply with
state NPDES regulations.
2. Implementation Concerns
2.a. Comment
How long would the responsible parties be responsible for
anything that might pop up, even after a thirty year
period? (F) .• ' • -
2.a. Response
This varies on a case to case basis, but it is usually
resolved by a cooperative agreement, or consent Degree that
will be established between the U.S. EPA and the
Potentially Responsible Parties (PRPs). In some cases,
monitoring may be done by the PRPs, the MDNR, or even, on a
local level, by the Public Health Department.
2.b. Comment
How will the problem of subsidence and maintenance of the
cap be dealt with? (E)
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2.b. Response
The subsidence factor will be an important consideration in
the Remedial design and action portion of the remedy. The
design will take into account the settling of the cap that
has occurred in the previous capping action. The cap will
also be monitored, and repaired when necessary.
2.c. Comment
Rather than fencing around the landfill, the county request
that U.S. EPA consider planting trees, shrubs and other
vegetation that will accomplish the purpose of restricting
entry to the landfill. (H)
2.c. Response
The main purpose for installing a fence at the site is to
protect the integrity of the cap by preventing pedestrian
and vehicular traffic across it and to keep trespassers
away from the gas vents. A "shrub- fence" would not be as
effective of a barrier as a chain link fence. However,
alternatives to a chain link fence may still be discussed
during the design stage of the project.
2.d. Comment
I would like to express my feelings about the closing of
the landfill. I am a resident of the area and am. in the
process of buying a home at 5745 Iris Street. I feel very
good about Alternative 4. I am. satisfied that the
recommenced' solution, from what was said at the meeting at
the Town Hall on August 17, 1988, is the best way to go.
(J)
2.d. Response
Comment noted.
2.e. Comment
The Pere Marquette Township Board, wishes to go on record
recommending that Alternative 5 rather than Alternative 4
be implemented by the U.S. EPA, since it includes a
groundwater collection system and an bnsite water treatment
plant. We feel very strongly that the groundwater
contamination problem must be addressed and that
Alternative 4 is an inadequate plan of action because it
does not address the groundwater problem. (K)
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2.e. Response
The U.S. EPA. believes that more information regarding
groundwater contamination is needed before a decision can
be made on a groundwater remedial action, such as more
information on the concentration of contaminants in the
groundwater and on the relationship between the groundwater
and the surface water. In addition, the effectiveness of
the soil/clay cap of Alternative 4 must be measured before
resources are expended on a pump and treat system. Testing
indicates that the soil/clay cap will reduce the leachate
generation within the landfill as much as ninety percent.
This will in turn decrease the amount of contamination
reaching the groundwater and therefore, in the future,
contaminants in the groundwater may be dilute enough to
fall below federal drinking water standards and acceptable
'risk levels.
By separating the remedial action at this site into two
separate operable units, one addressing the landfill
contents and one addressing-the groundwater, the U.S. EPA
can implement the remedial action for the landfill
contents, a remedy that is consistent with the final
remedy, while investigating the options needed to address
the groundwater concerns. This is the most cost effective
approach for the remedial action at the site.
2.f. Comment
Considering the known contamination of environmental media,
the U.S. Fish and Wildlife Service recommends that selected
organisms in Babbin. Pond, Iris Creek, and associated
wetlands be collected and analyzed as part of the
monitoring program for the two operable units. This will
permit the identification of actual risks to aquatic and
wetland biota, and, if actual risks are found, provide a
means to assess effectiveness of the selected remedial
actions through the life ;of thef: monitoring program. The
Service is willing to provide assistance in establishing
this program to monitor biota. (L)
2.f. Response
Your recommended additions to our monitoring program will
be taken into consideration during the development of the
monitoring program established to assess the landfill
contents operable unit and to further investigate the
groundwater operable unit.
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2.g. Comment
A. limited number of surface water and sediment samples
should be reanalyzed for the trivalent and hexavalent forms
of 'chromium, so as to confirm the assumed predominance of
the less toxic trivalent form. (L)
2.g. Response
Please see Response 2.f.
2.h. Comment
I am wondering if the consultant had a vested interest in
future work being accomplished on this site and I ask,
"does the investigative consultant proceed with the design
of any remedial actions?" If this is the policy of the
agency, that I believe that there exists an opportunity to
unconsciously prejudice the report and its conclusions.
While this may not be the case, I found the table which
listed all of the organic contaminants found at the site
impressive, but misleading, as ninety-five percent of the
compounds listed were found in either soil samples or air
samples from the existing methane vents.
These two sources were found to have assessment risks of
5xlO~10 for soils and 2xlO~7 to trespassers and not
quantified or non-detectable to residences with 400 feet of
the source of the bents. The listing of these contaminants
was misleading without clarification of some kind. (N)
2.h. Response
Initially, the U.S. EPA offered the PRPs the opportunity to
conduct the RI/FS, but since no agreement was reached, the
U.S. EPA. had its contractor conduct the studies. While the
contractor conducted the investigation and compiled the
RI/FS reports, the U.S. EPA in consultation with the
Michigan Department of Natural Resources approved the work
plans and the RI/FS report and selected the alternative to
best remedy the problem following established criteria and
guidelines.
The PRPs will have an opportunity to design and implement
the chosen remedy if an agreement can be reached during
RD/RA negotiations. If they decline it is possible that
the same U.S. EPA contractor could be awarded the design
and remedial action phases, although, usually, in the
absence of a settlement with the PRPs, the Army Corps of
Engineers conduct this phase.
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In response to the comment on the table of contaminants,
reports of industrial sludges and liquid wastes are
documented in site project files. They are not highlighted
other than to indicate past disposal practices at the site.
Table 3-3 of the RI report is useful as a catalog of all
contaminants found onsite and. their respective media. The
table reports the facts about the site. The interpretation
of these facts is presented in the risk assessment.
3. Environmental Impact/Risk Assessment Concerns
3.a. Comment
What type of contaminants are in the landfill? How much of
a threat are they to the aquifer? HOw persistent are they
in both the aquifer layers and in the landfill, assuming we
terminate the leachate with a cap? Is there direct contact
between the aquifer layer and what is in. the landfill now?
(B)
3.a. Response -
The wastes found are similar to those found in paint and
plating wastes such as solvents (benzene and 1,1-
dichloroethene) and heavy metals (lead, arsenic and
chromium). Two contaminants, benzene and 1,1-
dichloroethene, have been found in levels exceeding the
drinking water standards in the upper aquifer near the
landfill. The proposed landfill cap should decrease or
eliminate these concentration levels.
Groundwater concerns will, however, be addressed after more
investigation is performed. Based on historic aerial
photographs, soil borings, and present water levels, we do
not believe the waste is sitting within the aquifer.
The groundwater operable unit will address the drinking
water standards, and. the Applicable or Relevant and
Appropriate Regulations (ARARs).
3.b. Comment
What will the cap do to prevent contamination of the
springs in the area? (C)
3.b. Response
The cap addresses the downward percolation of the leachate;
it does not address the lateral movement of the groundwater
underneath it which flows to the north. However, since the
cap will prevent leachate generation, and the springs are
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8
outside the immediate area anyway, there is no reason to
expect them to be fed by anything other than just natural
groundwater.
3.c. Comment
When you state that benzene and toluene are in the
landfill, what are they contained in? Are they in drums,
and if so, when these drums deteriorate, will a cap keep
the chemicals from reaching the groundwater? (D)
3. c. Response
The records available for the landfill indicate that the
industrial wastes were in the form of sludge or liquid that
was disposed of in bulk within drying beds and later mixed
with the refuse. The landfill cap in Alternative 4, with
its drainage features, will alleviate the percolation of
water through the landfill and. the contaminated wastes
whould therefore remain within the confines of the
landfill.
3.d. Comment
The FS appears to take a rather limited view of the role of
Executive Orders 11988 and 11990 and the Fish and Wildlife
Coordination Act at the site. For example, the FS implies
that only vegetated wetlands are covered under Executive
Order 11990. The Service would classify Babbin Pond and
Iris Creek as open-water wetlands and include these areas
under the authority of the order. The Coordination Act is
also interpreted to apply solely to modification of flows
on Iris Creek. These statutes should, be re-examined
regarding their applicability to the site. (L)
3.d. Response
If Executive Orders 11988 and 11990 and the Fish and
Wildlife Coordination Act are deemed relevant and
appropriate for the Babbin Pond and/or Iris Creek wetlands,
the regulations will be applied to the site.
3.e. Comment
At this time, we object to the remedial action proposed by
the FS and the proposed. Plan to the extend that the chosen
alternative is inconsistent with CERCLA and other
applicable laws or regulations, and. further, to the extent
that the alternative is not warranted by actual conditions
at the site. (M)
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3.e. Response
The U.S. EPA believes that Alternative 4 is consistent with
CERCLA and other applicable laws and regulations. The
groundwater contamination at and near the landfill and the
presence of contaminants in excess of the Federal drinking
water standards warrant CERCLA action. While Alternative 4
does not directly address the groundwater contamination, it
is consistent with any final remedial action that will be
implemented at the site. In addition, the presence of
hazardous substances in the site requires a RCRA subtitle C
landfill closure.
3.f. Comment
Part of the investigative work seemed either inconclusive
or in need of further study. In particular, was the
electromagnetic portion which only suggested possible
plumes, the gamma ray logging of existing wells which was
intended to confirm existing well logs, and the purge
testing of the aquifer which gave values of the
coefficients of transmissivity of between 20,066 gpd/foot
and 348,654 gpd/foot. In my opinion, this range of values
is not usable for aquifer characterization, or for
conclusions to be based upon, although this information
would be needed more for the remedial action of the
groundwater than for the feasibility study. (N)
3.f. Response
The EM survey detected, a zone of elevated electrical
conductivity in the area directly north of the landfill.
There is a buried metal pipe in this vicinity that may have
caused the elevated readings. It is possible that a thin
layer of clay, characteristic of the site's stratigraphy,
could have caused the elevated conductivity. Since
contaminants were detected in well MW07 which is located
north of the landfill, the report concluded that there was
a contaminant plume migrating to the north and northwest
from the landfill.
Gamma log data corroborated the stratigraphy of existing
logs (of wells that were not installed as part of the Rl)
and provided data for wells without recorded logs. Well
logs were used to develop the site stratigraphy which was
used to interpret aquifer characteristics.
Based on the information presented in Table B-l of the FS
report, the transmissivity of the upper aquifer ranges from
260 gpd/foot to 12,000 gpd/foot. The transmissivity
depends both upon aquifer thickness and hydraulic
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10
conductivity, but the variation of hydraulic conductivities
is responsible for most of the difference in
transmissivities at this site. Hydraulic conductivities
can and typically do range several orders of magnitude for
different points within the same aquifer, and the data
obtained in the RI fall within this range. For all
calculations involving groundwater flow or groundwater
collection, the range of hydraulic conductivities was used.
This was intended to provide a reasonable range of
contaminant migration velocities and groundwater collection
rates. The sensitivity of the groundwater collection and
treatment alternative to the range of collection rates was
provided as parj: of the cost estimate in the FS.
3.h. Comment
The report identifies the various vehicles from, which the
public could come into contact with pollutants from the
landfill and then assesses the risk of this contact by
calculating the probability of a death caused by this
exposure. A more complete "discussion of Risk Assessment
could have been accomplished so that the readers could
understand risk assessment and its effect on what should or
should not be accomplished as far as remedial action is
concerned.. From. Table 1-1 the following are summarized
with comments:
VEHICLE FOR EXPOSURE
Drinking water off-site - The exposures for this category
were determined from two sampling events of two residential
wells off-site. In the first phase (Nov. 1986) detection
of two organic compounds were found which gave a
probability risk of 3xlO~6 and 7xlO~7. These two wells
were replaced by deeper wells and the second phase of
testing (Dec. 1987) found these and other organic compounds
to be non-detectable and having a risk of zero. Recently,
the EPA. determined that,, simply-speaking, landfills should
pose a health risk of no more than 1 in 10,000,000 or
IxlO"7. It is seen from this that this vehicle for
exposure is not a particular problem for this landfill in
its existing geologic setting and is above EPA's published
expectations for landfills.
Drinking water on-site - This vehicle assumes that a
drinking water well will be placed on-site and used for
potable water purposes. The risks for this occurrence are
between IxlO"3 and 2xlO~5 for the upper aquifer and 2x10 °
for the lower aquifer. These assessments are from Well
No.7 which contained benzene and Well OWAI which contained
1,1-dichloroethane during the phase one testing.. This is a
real risk, one that cannot be ignored. However, it should
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11
be tempered with the knowledge that the chance of a well
being drilled on site is nil. The county owns the site and
understands the ramifications of a well being drilled.
Intelligent use of deed restrictions would prevent a well
from being drilled on this site. If a well is not drilled,
then the risk: is zero.
Surface water - Not quantified, no levels to report, and no
risks. This vehicle is well beyond EPA. standards and
should become one of the most important yard sticks of
determining a course of remedial action, and to what degree
the existing cap is to be addressed. (N)
"•
3.h. Response
A. complete discussion of the methodology, assumptions and
results of the risk assessment, including numerous
references to published documents, is provided in Appendix
H of the RI report.
Existing residential wells downgradient of the landfill do
not currently pose a health threat to receptors. Since
contaminated wells were abandoned after Phase 1, the
sampling point was not available in Phase II. The aquifer
could, still be contaminated at that location. The
hydrogeologic setting of the site indicates that
groundwater in the upper aquifer flows beneath the site to
the north and northwest in the direction of off-site
residential wells. Also, groundwater from the upper
aquifer has a pathway to the lower aquifer. Trace levels
of volatile organic compounds were detected in monitoring
wells screened in the lower aquifer along Inman Road, and
an excess lifetime cancer risk of 7xlO~° was determined.
There is a potential for contaminants to migrate to off-
site residential wells.
It is not possible to predict the future use of the site or
ensure that drinking supply wellsVwili not be installed on-
site. The aquifer is contaminated above established
federal and state limits, and future contaminant levels
cannot be predicted.
Surface water bodies on or near the site are not considered
to be sole indicators of groundwater contamination at the
site. Much of the health risk that was determined for
exposures to groundwater at the site results from the
presence of volatile organic compounds (VOCs). These
compounds volatilize upon contact with air. Thus, they
would not be detected at concentrations that are
representative of the groundwater after it discharges to
the wetlands and Iris Creek. Also, all of the groundwater
that flows beneath the landfill in the upper aquifer does
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12
not discharge to t^he wetland or Iris Creek. Rather, some
groundwater migrates to the north and northwest, and some
migrates to the lower aquifer.
3.i. Comment
Supposedly, the report does identify two separate operable
units which need to be addressed and they are one; landfill
contents and two; groundwater, on site. Based, on results
within the report, I believe that these conclusions should
be questioned.
Based on computer modeling results presented in the RI
report, it seems that the landfill contents are not a
problem as a single source of contamination. Further,
since the leachate discharges to surface water and the
surface water risks are zero under current conditions, the
landfill contents are not a risk. (N)
3.i. Response
The site was separated into the landfill contents and
groundwater operable units because these are the two media
onsite with contaminant levels high enough to threaten
public health and the environment. Operable units for
surface water, surface soils, and. sediments were not
included because risk associated with exposures to these
media are low. Also, it is anticipated that remediation of
the other operable units will reduce the contaminant levels
of these media.
The computer analyses done in the RI used approximate and
idealized models of the existing aquifer system.
Assumptions of the models were presented in the RI report.
Two models were investigated, one representing a. slug of
contamination, the other representing a continuous source
of contamination. Based on the results of the analyses, it
was concluded that a slug of contamination is not likely to
cause exceedance of maximum contaminant levels (MCLs) or
aquatic water quality criteria (AWQC). However, it was
also concluded that continuous loading of small quantities
of contaminants (2 x 10-3 to 7 x 10-4 gpd) to the
groundwater could cause exceedances for MCLs and AWQC. The
intent of the analyses was not to specifically predict or
quantify aquifer contamination. Instead, it indicates that
continual leaching of contaminants to the groundwater is
more likely to cause problems in the aquifer than sudden
releases.
Using the surface water to indicate groundwater
contamination at the site was discussed in the previous
comment. Surface water is not considered to be
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13
representative of the groundwater^. Although, the health
risk associated, with exposure to surface water are
anticipated to be low, they are not quantified. This does
not signify that such risk is zero.
Based on the data generated in the RI, the landfill
contents are currently causing the aquifer to be
contaminated to levels that exceed MCLs for benzene and 1,1
dichloroethene. For this reason, the landfill contents are
a threat to public health and the environment.
3.j. Comment
The estimate of leachate generation should be reevaluated.
The long-term ability of the drainage layer in the soil-
clay cap to drain excess water is doubtful, and a surface
layer cap would be more advantageous because of easier
inspection and maintenance. (N)
3. j. Response
Leachate generation was estimated according to water
balance procedures outlined in EPA. guidance. The
calculations and necessary assumptions are presented in
Appendix A of the FS report. All three capping options
(i.e. existing cap, regrading and revegetating, and soil-
clay cap) were evaluated using the same runoff coefficients
of 20% (summer) and 15% (winter). The runoff coefficient
was selected based on surface slope and vegetative cover,
form published data (Handbook of Applied Hydrology, Chou,
1964, p. 14-8). After visual examination of the existing
cap it was estimated that runoff for existing conditions
could, be reduced about 25% because of landfill subsidence
that has created ponded areas and loss of slope. The
resulting water balance calculation gives an estimated
infiltration of 5.2 inches/year. If the 25% reduction is
not applied, the resulting infiltration would be 4.7
inches/year. This does; not 'significantly change that
percentage of reduction associated with each cap
improvement.
The ability of the soil-clay cap at reducing infiltration
is partially dependent on the drainage layer to remove
water. Subsidence is a problem and the final design win
have to take it into consideration. Slopes might need to
be exaggerated to reduce the effect of subsidence,
differential settlement could be monitored to indicate
where subsidence is occurring (to indicate where
maintenance may be needed), and different materials besides
sand and drainage pipe might be need (e.g. geodrains).
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14
3.k. Comment
I believe two questions should be asked and answered as
simply as possible before proceeding with a remedial action
project. First - is the affected, aquifer (the upper)
available now and in the future as a source for drinking
water? The answer is no. And secondly - In this area is
it economically feasible to locate a usable source of
drinJcing water? The answer is yes, as documented by the
re-drilling of two residential wells, mentioned earlier.
Based on these answers, I do not believe that remedial
action .of the ground water is currently needed or apparent
based, upon the performance of the existing cap and the risk
assessment given to the surface waters and off-site
drinJcing water aquifers.
I also believe that the public can be protected by fencing
this site, passing deed restrictions (if not already
accomplished) and by continuing to monitor the site. I
also feel that the cap should be maintained on a regular
basis and believe that the MCDPW has the staff and
experience to accomplish this function and suggest that a
modified Alternative Number 2 be accomplished to that
effect. (N)
3.k. Response
Even though there are no drinJcing water wells within the
upper aquifer right at the landfill, a number of residents
around the area still use the upper aquifer for their
drinJcing water supply. Although no residential wells are
presently contaminated, the potential for the contamination
to migrate away from the landfill and to these residential
wells is real.
It is economically feasible to utilize the deeper aquifer
for an alternate drinking water supply, as some residents
have done. However, the existing cap is not effective at
reducing infiltration, contaminants are present in the
aquifer immediately downgradient of the landfill and the
potential exists for contaminants to migrate offsite. The
RI report has shown that the upper aquifer does intermix
with the deeper aquifer, so the potential does exist that
if the contamination of the upper aquifer continues, the
deeper aquifer also would become contaminated. To achieve
the protection of human health and the environment,
Alternative 4 was chosen as an interim remedy because it
will secure the landfill contents better than the present
landfill cap, and therefore help reduce the amount of
contamination reaching the groundwater.
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4. Funding concerns.
4.a. comment
Who is going to pay for the clean up? (E)
4. a. Response
The Potentially Responsible Parties, PRPs, will be
ultimately responsible. U.S. EPA will not, however, wait
for the case to be settled if we can not negotiate an
agreement. We will go ahead with the remedial action and
attempt to recover the costs later.
4. b. Comment
The county recommends that EPA carefully review its
estimates of the cost for remedial Alternative 4. The
county believes that the cost estimates are unrealistically
high. (H)
4.b. Response
The cost estimates are order-of-magnitude estimates with an
expected accuracy of +50% to -30%. cost estimating
references and assumptions are presented in the FS report.
The cost estimate is intended to help in the decision
making process by estimating budget requirements for each
alternative. If costs are inflated or deflated "across the
board" for each alternative, the relative effect is minimal
and the decision making process is not prejudiced.
4.c. Comment
The RI lists different PRP's than what the original summons
did two years ago and I'd like to see that is properly
addressed. (E)
'- ' • •>•"
4.c. Response
The PRP list at this time is the same as it was during the
RI/FS negotiations two years ago. The RI report states
that D&C Disposal is a PRP but they are not now considered
a PRP, while Ed Dains, past site owner is considered a PRP,
though even he is not listed in the RI report. If the
county or any one else has information that indicates other
PRP's, the U.S. EPA is willing to send information request
letters to those parties if there is substantial evidence
to warrant such a. request.
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5. Property value concerns.
5. a. Comment
We'have a pond that is fed by Iris Creek, downstream from
the landfill. Since around 1981, we have noticed
deterioration of this pond and the loss of fish, can this
be caused by the landfill, as several realty companies are
suggesting? Can any sampling be done of my pond? Will
this new cap help taJce care of our problem? (G)
5.a. Response
As noted in the RI report. Iris Creek was sampled and no
significant contamination was found in downstream Iris
Creek, locations. Where as it is possible that past
contamination from the landfill may have reached downstream
locations, our surface water and sediment sampling does not
suggest this. More investigations will be occurring to
evaluate the groundwater effects to the surface water and
to evaluate the effectiveness of the cap. This on-going
investigation may be expanded to include points further
downstream.
6. Notification period and response time concerns.
6.a. Comment
We (the governing bodies of the county) have been allowed
only one month to respond and comment. It is almost
impossible for a government to respond that cniickly. Will
you accept any comments after August 31? (E)
Mason County was not aware that the U.S. EPA intended to
select remedial Alternative Number 4 until the public
meeting on August 17, 1988. The county did not receive the
final reports until about a week after the start of the
public comment period on August 8, 1988. The 23 days total
or 14 days from the public meeting, given to for public
comment is not long enough for the county to review the
documents and respond can more time be given for comments
from the county? (H)
6. a. Response
The U.S. EPA is under Congressional deadlines and time
limits to clean up Superfund sites. While we cannot accept
comments after August 31, no comments will be ignored. It
may be possible to work them into the design stage or
further on in negotiations. We realize that it is very
difficult for a municipality to respond quickly; this issue
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17
is being discussed currently in agency headquarters in
Washington D.C. with the Municipal Settlement Group.
According to U.S. EPA record, Tim Hansen, Mason County
Department of Public Works was sent a Final RI report on
JUly 14, 1988 and a Public Comment FS report on August 5,
1988. The proposed plan was expressed mailed to Tim
Hansen, on August 4, 1988. Also, all these documents were
available for public review on or before August 8, 1988.
6.b. Comment
The public comment period on the Feasibility Study (FS) and
proposed RAP was initiated on August 8, 1988 and expires on
August 31, 1988, allowing only 21 days (15 working days) to
.provide written comments. The only apparent notice of the
public comment period to Straits Steel as a PRP in this
matter was provided by the EPA's August 24, 1988 letter
(the "special Notice of Potential Liability"). This is
clearly inadequate notice, coming well after the public
comment period was initiated.1
Given the complexity and importance of the issues involved,
this short comment period does not provide sufficient time
to thoroughly review the relevant materials and has unduly
restricted our ability to comment on the appropriateness of
the proposed alternatives. The lack of an adequate period
to provide for thorough review and submission of comments
may constitute a violation of due process. (M)
6.b. Response
The U.S. EPA, following NCP guidelines, has allowed 21 days
for public comment. The FS report and the proposed plan..
Actually, 23 days were available for public comment, August
8 through August 31, 1988. Appropriate notice was given
announcing the public comment period and the EPA's
preferred remedial action; as tnis was published in the
local newspaper prior to August 8, 1988. Also, Mason
County, the main contact throughout the RI/FS negotiations
was informed of the timeframe for the public comment
period. All appropriate documents were available for
reviewing at the Ludington Library, Mason County Courthouse
and at the Pere Marquette Township Hall, on or prior to the
initiation of the public comment period on August 8, 1988.
6.c. Comment
We object to the initiation of the 60 day period of
negotiation to establish a "good faith" proposal for
implementing and conducting the remedial action as having
been initiated too early. First, the Record of Decision
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18
("ROD") to select the appropriate remedial action has not
yet been issued. In the absence of a final decision on the
remedial action, it is impossible for the PRPs to agree to
"a detailed statement of work" identifying how they may
proceed with the remedial action, or to meet the other
elements which the U.S. EPA has indicated must be included
in a "good faith" proposal. Second, while the U.S. EPA has
prepared a list of six (6) PRPs, it is probab-le that other
PRPs remain unidentified in connection with this municipal
landfill. We fail to understand how the negotiations on a
"good faith" proposal can proceed until all of the
necessary parties are at the table. Accordingly, we
request that the period of negotiation be extended to run
60 days from such time as the ROD has been issued and/all
PRPs have been identified. (M)
6.c. Response
The negotiation period for the Remedial Action routinely
starts prior to the signing of the ROD so that by the time
the PRPs arrange themselves into an organized group and
review the pertinent documents, the ROD is well on its way
toward finalization. By doing it this way EPA resources,
as well as time, are conserved. With regard to obtaining
more PRP's for this site, at the present time EPA, does not
have any other information indicating PRPs other than, those
that have already received special notice regarding RD/RA
negotiation. U.S. EPA is willing to pursue other PRP's if
the information provided indicates PRP involvement with
hazardous substances being disposed of at this site.
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APPENDIX A
List of CooKnters on the Mason County
Feasibility Study and Proposed Plan
liaae
(A) John Wolkow
(B) Dave Cherba
(C) George Cluehey
(0) Kathy Uinczewski
(E) Tim Hansen
(F) Connie Anderson
Affiliation
Resident
Resident
Resident
Resident
Mason County
Pere Marquette TWP
(G) Mr & Mrs Robert Rasch Resident -
(H) Robert P.Tremp
(I) Tim Hansen
(J) Larry Gustafson
(K) Stanley Jansen/
Joanne Kelley
(L) Robert D. Pacific
(M) George B. Davis
(N) Dennis Dunlap
Attorney representing
Mason County
Mason County
Resident
Pere Marquette
Charter TWP Board
U.S. Fish & Wildlife
Serv ice
Attorney representating
Strains Steel &.;:Wire Co.
• ~. ~
Westshore Engineering
and Surveying Inc.
Source of Coaaent
8/17/88 Meeting
8/17/68 Meeting
8/17/88 Meeting
8/17/88 Meeting
8/17/88 Meeting
8/17/88 Meeting
8/29/88 Letter
8/30/88 Letter
8/12/88 Phone Call and
8/17/88 Meeting
8/19/88 Letter
8/24/88 Letter
8/29/88 Letter
8/31/88 Letter
8/31/88 Letter
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