United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R07-91/046
May 1991
Superfund
Record of Decision:
El Dupont De Nemours
(County Rd X23), IA
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50272-101
REPORT DOCUMENTATION 1'. REPORT NO.
PAGE EPA/ROD/R07-91/046
I ~
3. Recipient'e Acce88lon No.
..
... 11118 and ~tlde
SUPERFUND RECORD OF DECISION
E.I. Dupont De Nemours (County
First Remedial Action - Final
7. Author(e)
5. Report Dete
OS/28/91
Rd X23), IA
6.
8. Perfonnlng Orgenlzatlon Rept. No.
8. PWrIonning Orgalnlzatlon Heme and Add,...
10. Projec1lTuklWoril Unit No.
11. ConInIct(C) or Gr.nt(O) No.
(C)
(0)
1~ Spw80rtng Org8l'llz8llon Heme and Addre..
U.S. Environmental Protection
401 M Street, S.W.
Washington, D.C. 20460
13. Type 01 Report & Period Covered
Agency
800/000
14.
15. Supplemen1aly No...
16. Abatract (Umlt: 200 _rde)
The E.I. DuPont De Nemours (County RD X23) site is a paint waste disposal site 3.5
miles south of West Point in Lee County, Iowa. The site is divided into two
sub sites, McCarl and Baier, which are three-fourths of a mile apart. Land in the
area is agricultural, residential, and woodlands, and the nearest residence is
located 500 feet from the McCarl subsite. The site overlies two water-bearing units,
separated by 75 feet of very low permeable clay. The Baier subsite was used as the
primary disposal site, and the McCarl subsite was used when weather did not allow
access to the Baier site. From 1949 to 1953, an estimated 48,000 to 72,000 55-gallon
waste drums were disposed of at the two sites. Paint waste was generally placed in
trenches and burned, resulting in an estimated 4,500 to 7,000 tons of ash remaining
on site. Paint cans, ash-like material, and sludge casting were also visible on the
surface of the site. In 1983, an EPA investigation of the Baier Farm detected levels
of metals and organics in excess of soil background levels. In addition, ground
water monitoring wells, installed during 1985 and 1986, detected metal concentrations
above MCLs. A 1989 investigation identified the source of contamination as paint
disposed of on site. Removal from the Baier site was scheduled for July 1989 by a
(See Attached Page)
17. Document Analyale L Deecriptore
Record of Decision - E.I. Dupont De
First Remedial Action - Final
Contaminated Media: soil, debris
Key Contaminants: metals (cadmium,
Nemours (County Rd X23), IA
chromium, lead, selenium)
b. IdentiIler8lOpen-Ended Terme
c. COSA 11 ReIdIOroup
18. Ave/lebility Statement
18. Security CI... (Thle Report)
None
20. Security Cle.. (Thl. Pege)
N()n~
21. No. 01 P.gee
60
I
n PrIce
(See Af6.Z38.18)
See Instructions on Reveree
272 (4-77)
(Formerly NTlS-35)
Department 01 Commerce
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EPA/ROD/R07-91/046
E.I. Dupont De Nemours (County Rd X23), IA
First Remedial Action - Final
Abstract (Continued)
Unilateral Administrative Order from EPA to DuPont, but deferred by a February 1990
amendment. This Record of Decision (ROD) addresses the soil, debris, and ground water,
as a final remedy. The ground water was determined to be of little threat and is not
further addressed by this ROD. The primary contaminants of concern affecting the soil
and debris at both subsites are metals including cadmium, chromium, lead and selenium.
The selected remedial action for the site includes stabilizing/solidifying the
contaminated soil at both subsites, and covering the stabilized mass with clean soil
and vegetation; removing and disposing offsite all surface debris not amenable to
solidification at an authorized RCRA landfill; monitoring ground water; and
implementing institutional controls including deed restrictions. The estimated present
worth cost for this remedial action is $1,400,000. There are no O&M costs associated
with this remedial action.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific soil clean-up goals are based on
health-based criteria, and include lead 350 ug/kg, selenium 10 ug/kg, and cadmium
20 ug/kg.
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Uf'\!TED STATES ENVIRONMENTAL PROTECTIOt\ AGEf\:Y
REGION VII
726 MINNESOTt.. AVENUE
KANSAS CITY, KANSAS 66101
5/3.i (1(
MEMO~DUY.
Sl"EJE2T;
Recc~d of Decision for DuPont County Road X23
S~perfund Site ~
David v.;agoner. . L
Di re:::'o~ I \\aste' . ment Division
}:o~ris Kay
Regional Adreinistrator
FEO:': ;
IC';
This Reco~d ef Decision package presents a proposed re~edy
fer the s~lid:fication/stabilization of contaminated soil at the
D",yo:1't Cc:;:-:":y Road X23 Superfund Site in Lee County, I 0\0; a . This
~ill be the final remedy for this Site.
T~e ~~Jc~ ce~pone:-:t of the proposed remedy includes the
rE~=~a: c! s:;~fa::e ~aste, the solidification/stabilization of
aFP~exi~a~ely l~,OOG cutic yards of contaminated soil, coverin;
the stabilized ~ate~ial ~ith soil, and continued monitoring.
1,0 actic:-: ~as preposed as the remedy for ground water base~
0:-: the la::}: cf exposure pathways. This decision was based on the
very lo~ yield of the ~ater bearing unit at the site, and the
presencE c: a thic}: confining layer below the water bearing unit.
This action has been coordinated with the Office Regional
Cou:-:se:, the Office of Public Affairs, the congressional and
Intergovernmental Liaison, and the Agency for Toxic Substances
and Disease Registry (ATSDR).
The Iowa Department of Natural Resources has concurred on
the proposed remedy.
On Dee-ember 27, 1991, the remedy selection authority fo'. the
DuPont County Road X23 Site was delegated to you by Don R. Clay,
Assistant Administrator. I recommend approval of the proposed
remedy.
Attachr..ent
~:"YC:" .
n.." ~t. .
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r. !.
RECORD OF DECISION
D:: pcn;: DE NEMOURS AKD COM PAl-PI COtTh"'!Y ROAD %23 SITE
WEST POI~T, LEE COUNTY, IO~A
Decl ara tior.
1.0
Site Na=e and Location
E. r. d~ ~cnt de Necours and Company County Road X23 Site
Lee Co~n~y, Io~a
1.1
statement of Basis an~ Pur~ose
Th:s decision docu~ent presents the selected remedial
a=tic~ :c~ ~~e E. I. D~Pont de Nemours and Co~pany Coun~y
Road X23 Site, located in West Point, Lee County, Iowa and
was developed in accordance with the requirements of the
Co=prehensive Environmental Response, Compensation, and
Liabili'ty hct 0: 1980 (CERCLA), ~s amended by the Superfund
~=e~=~~~:~ a~= Reauthorization Act 0: 1986 (SAP~) and, to t~e
ex~e~t F~ac~icable, the National 0il and Hazardous Substances
Pollution Con~inge~cy Plan iNCP): 40 CFR Part 300 (1990).
This de:isio~ document explains the factual and legal basis
for SE:Ec~:ng the remedy for this site.
:~E Ic~a Department of Natural Resources cor.=~rs ~it~
the se~ec~ed remedy. The information supporting ~~is
recedi~l action decision is contained in the Admi~istrative
Reccre :c~ this site, ~hich is available for public revie~ at
the 1==: Rastid Me~orial Branch of the Fort Madison Public
Libraries, 3421 Avenue L, Fort Madison, Iowa, and at the
Environ~ental Protection Agency Regional Office located at
72E }:ir.nesc~a hvenue, Kansas City, Kansas.
1.2
Assessment of the Site
Actual or threatened releases of hazardous substances
fro~ this site, if not addressed by implementing the response
action selected in this Record of Decision (ROD), may present
a current or potential threat to public health, welfare, or
the environr::ent.
1.3 Description of the Selecte~ Reme~y
1.3.1
Ground Water
The selected remedy for ground water is no action.
is based on the conclusion that no completed human or
This
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s~~s:~iv€ e~vi~on~~~tal exposure pathway exists for ground
~ater. Depth to the groundwater at this site is
aFF~o>:i~~t€ly 30 feet belo~ ground surface. The upperr.ost
~ate~-bea~ing unit at the site is considered unusable as a
g~ound ~ater-producing aquifer due to the extremely lo~ yield
fro~ the unit, the lo~ permeability of the unit and the
presence of a confining unit below the water-bearing unit.
Hc~ever, ~onitoring of the ground water will be continued.
1. 3.2
Soil
Heavy metals contamination in the soil represents the
p~incipal threat at the County Road X23 Site based on the
risk to sensitive populations, the risk posed through
possitle ingestion of vegetables grown in contaminated soil,
anc the risk for possible future residents. The major
cor.~=~€~~S cf the selected remedy for soil, which is designed
to accress heavy metal and volatile organic contamination,
include the follo~ing:
...,
Surface debris removal~
Statilization/Solidification of contaminated' soil;
and
Instal13tion of top cover to protect stabilized
soil.
1.4 Declaration of Statutory Determinations
T~e selected remedy is protective of human health and
the environment, complies with federal and state requirements
that are legally applicable or relevant and appropriate to
the re~edial action, and is cost-effective. This remedy
utilizes permanent solutions and alternative treatment
technologies to the maximum extent practicable, and it
satisfies the statutory preference for remedies that employ
treatment that reduces toxicity, mobility, or volume as their
principal element.
Because this remedy will result in hazardous 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.
A~/{~
Morr s Kay
Regional Administrator
U.S. EPA. Region VII
.s,.2?1'-'1/
Date
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DECISIO~ S~~Y
1.0 Site ~~e, Location an~ Description
The E. I. du Pont de Nemours and Company County Road X2~
s:t€ is lo=a~e= in rural Lee County, Iowa, approximately 3.5
~iles sout~ fro~ West Point as shown in Figure 1. The Site
consi£~s cf two subsites, the McCarl Subsite and the Baier
S~bsite. The Baier Subsite is located in the North East
quarter of the South West quarter of Section 28, Township ES
Ncrth, Range 5 West (Figure 1) and includes property owned by
Richar~ Fedler. The McCarl Site is located in the Soutt East
quarter of the So~th West quarter of Section 22, Townstip 68
l;orth, Range 5 ~est (Figure 1). The two subsites are
appro~i~ately three fourths of a mile apart. The land
adjace~t to the sites is used for agricultural or residential
purposes. other adjacent land is left in a wooded state.
The nearest residences are approximately 500 feet f~om the
t-~cCarl S-.:.bsi te.
2.0 site History an~ Enforcement Activities
DuPo~t hired a contractor to haul and dispose of paint
v:astes frc~ their Fort Madison plant during the period 19~9-
--' h~ esti~ated 46,000 to 72,000 55-gallon drums of waste
v:e:re cisp::sej of at the t...'o subsi tes. The Baier Farr.. ...;a5 thE:
pri~ary disposal site. In inclement weather when the Baier
Farm ~as inaccessible, the McCarl Site was used. The ~cCarl
Site ~as F~rchased by DuPont in 1986. The paint waste was
placed in trenches and burned. An estimate for complete
burning indicates that 4,500 to 7,000 tons of ash might
re~ai~ c~ the sites.
The Baier Farm was listed as a potentially,
unco~trcllej, hazardous waste site in the Eckhardt
Subco~~ittee Report in November 1979.
A hazard ranking system (RRS) package for the E.I. du
Pont de Nemours and Company County Road X23 superfund Site
(the "County Road X23 site" or the "Site") documented a score
of 46.01. The Site was proposed to be included on the
National Priorities List (NPL) in the June 1988, 7th update.
This listing beca~e final on the NPL in \ugust 1990.
A field investigation of the Baier Farm was conducted by
the Field Investigation Team (FIT) in April 1983. Soil
sample analysis found seven priority pollutant metals in
concentrations exceeding background. Also detected were si~
priority pollutant organics in soil samples.
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o~, Y.a~=~ 2E, 1984, EPA sent a CERCL; 10~(e) inforr.,atio~
re~~est lette~ tc DuPcnt regarding the Baier Fa~. DuPc~~'s
resp~~ss in=icate= another possible waste site at the Y.cCar:
p~ope~~y C~ Chalkridge Road.
In July of 1985 FIT oversaw the installation of three
g~ou~d ~ate~ r.onitoring wells at the Baier Farm. Analyses of
g~o~~j ~a~e~ sar.ples collected from the wells showed elevate=
levels cf ~e~a~s. A second round of sampling of these we:ls
i~ 19EE res~lte= in si~ilar findings. Downstream surface
~ate~ sa~~les sho~ed elevated concentrations of metals.
FIT conducted the Site Investigation for the McCarl
subsite ir. July 1986, including the installation and sa~pling
of three ground water monitoring wells. Analysis of soil
sar.ples fro~ the investigation showed concentrations in
exces£ c! tackg~ound for metals. Analysis of ground wate~
sar.ples sho~ed concentrations in excess of Safe Drinking
Water Act y.axirnur. Contaminant Levels (MCLs) for several
metals.
A ~;~:~~: ~=~ice letter to initiate negotiations
regarj~n; ~e~e=ial Investigation/Feasibility Study (RI/FS)
neg=t:a~ie~s ~as sent to DuPont on January 31, 1989.
o~ June 19, 1989, EPA sent DuPont a 104(e) letter asking
f=r da~~ fre~ work conducted at the Site by DuPont's
ccns~:ta~~ d~~in; Y.ay 1925.
After RI/FS negotiations concluded unsuccessfully, the
E?h issue= a U~:lateral Adr.inistrative Order to DuPont on
Ju:y ~, ~5=S. Tt:s order required a removal action at the
Baie~ s~tsite and an RI/FS for both subsites. An amendmer.:
to the Cr.ilateral Order on February 7, 1990, deferred the
require~e~~ fer the removal.
The RI/FS was completed in September 1990. The final
RI/FS report was completed January 15, 1991. The results of
the investigations are discussed in Section 5.0.
3.0 Highlights cf ccmmunity Participaticn
The RI/FS Report and the Proposed Plan for the County
Road X23 Site were released to the public for comment on
April 11, 1991. These two documents were made availabl~ to
the public in both the Administrative Record and an
information repository maintained at the EPA Docket Room at
the Region VII offices and at the Idol Rashid Memorial Branch
Public Library, Fort Madison, Iowa. The notice of
availability for these two documents was published in the
Fort Y.adison Dailv Democrat on April 12, 1991. A public
co~~ent period on the documents was held from April 11, 1991,
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6
t= ~ay ~l, 195:. In addition, a public meeting was held on
hF~~: lE, 1991. At this meeting, representatives fro~ EPh,
Io~a Depa~trnent of Natural Resources (IDNR), and Iowa
Depart~ent 0: Health (IDOH) answered questions about the Site
and the re~edial alternatives under consideration. Responses
to the comments received during this period are included in
the Responsiveness Summary, which is part of this ROD. The
de=isio~ for this site is based on the Administrative Record.
4.0 Scope and Role of Response Action Within site strategy
As ~ith ~any Superfund sites, the problems at the
Cou~ty Road X23 Site are complex. The selected response
addresses the principal threat due to soil contamination.
Based on in~estigations of the site during 1989 and the
Remedial Investigation, the source of contamination at the
site ~as identified to be paint waste disposed of at the sit~
by DuPor.t. Of particular concern is the presence of (threat
posed by) the heavy metal contaminants in soil at present
levels of concentrations if the site is used for residential
or agricultural purposes. The ground water alternative is no
actio~ based on the conclusion that no completed exposure
path~ay exists for the ground water. This is due to the
extre~ely lo~ yield fro~ the contaminated upper water-bearing
ur.it a~ the site, the low permeability of the unit, and the
prese~ce of a confining unit below the water-bearing unit.
Eo~eve~, ~=r.itoring of the ground water will be continued.
The response actions selected in this ROD address all
principal threats posed by this site and are intended to
constitute final action for this site.
5.0 Summary of Site Characteristics
The nature and extent of contamination of ground water
and soil at both subsites is summarized below. This summary
is based primarily on data generated by the work performed by
DuPont ir. Xay through August of 1989 and in the RI. Detailed
information regarding the nature and extent of contamination
can be found in the Final RI Report (January 16, 1991).
5.1 Baier Subsite
The approximate areal and vertical extent of disposed
waste material was estimated by probing with a hand auger
during the May 1989 investigation. Figure 2 shows the
approximate areal extent. Depths to the contact between the
waste and native soil ranged from approximately two inches
below grade to greater than 36 inches below grade. Samples
collected from the waste material showed high levels of lead,
cadmiu~, chromium, selenium, and zinc (Table 1).
Concentrations of metals contaminants were highest in the
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~:~~c ~=:€~ic: i~se::, ~ith lesser, but still eleva~ed,
conce~:~a:ion~ li~itej to the upper two to three fee: belo~
the inter:acE bet~een the waste and native soil. Elevated
ccncentra~io~s of several volatile organic compounds were
also detec~ed in the waste material. Evidence of migration
of volatile and se~i-volatile organic contamination was noted
as deep as 16 feet below the waste/native soil contact
(Tables 2, 3). The RI focused on characterizing the
horizor.~al and vertical extent of contamination outside of
the waste disposal areas. Generally, this investigation
showed tha~ contamination was limited to within 50 feet of
the areas of waste disposal. contamination in these areas
were generally restricted to the upper four feet of soil.
Sa~pling did show elevated concentrations of metals (only) in
several drainage ditches leading from the subsite.
Conta~ination was limited to within 50 feet of the ditch
heads. Heavy metals contamination in the soil represents the
principal threat at the Baier Subsite based on the risk to
sensitive populations, the risk posed through possible
ingestion of vegetables grown in contaminated soil, and the
risk to possible future residents.
Based on terings cowpleted at the subsite, two
hydraulically sepa=ate water-bearing units have been
identified. ~\-h, ~~-B, MW-C, MW-D1, MW-E, MW-F, MW-G, MW-H,
r-~";-I I !"~..:-J I M"I";-El and ~-Ll are all monitoring wells
co~~le:€d ir. the uppe~ water-bearing zone, which is located
fro~ 2~ tc 7C feet below ground surface. See Figures 3h and
3B fer w€:~ locations. ~-D2, ~-F2, MW-K2 and MW-L2 are
~onitoring wells completed in the lower, unconsolidated
water-bearing zone, which is approximately 130 to 140 feet
below ground surface. Analytical results for samples
collected to date indicate that contamination is limited to
the upper-~cst water-bearing zone and has not migrated to the
deeper water-bearing unit. The primary reason for this
appears to be the presence of a thick (over 75 feet) low-
permeability clay till layer between the upper and lower,
unconsclidated water-bearing zones, which significantly
limits the movement of water between those zones.
Analytical results for samples collected from the upper-
most water-bearing zone showed significant volatile organic
compound contamination in MW-F with lesser concentrations of
organics in ~-A and MW-G. Elevated concentrations of total
metals were detected in most of the shallow wells. Elevated
levels of contaminants were not detected in wells completed
in the deeper unconsolidated water bearing zone.
Due to the low yield and low permeability of the upper
water-bearing unit, and the confining layer separating the
water-bearing units, it was determined that a completed
exposure pathway for ground water does not exist at the site
for humans or environmentally sensitive receptors.
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5.2 ~c:arl Subsite
\'iSu~l obser,a~ic~s wade during aug~ring and test ~it
excavatic~5 at the ~cCarl Subsite in May 1989 sho~ed that tte
a~ounts of disposed paint wastes were much s~aller than at
the Baier Subsite. While some paint cans, ash-like material,
and sludge castings can be seen at the Subsite, there do not
appear to be concentrated, significant areas of waste
disposal as was observed at the Baier Subsite. Soil sa~ples
collected during pre-remedial and RI field investigations
indicated concentrations of cadmium, chromium, selenium,
lead, and zin= above naturally occurring background ranges
(Table 4). For illustrative purposes, Figure 4 shows where
these metals ~ere above background concentrations.
Generally, elevated concentrations are limited to the upper
four feet of soil. Sa~pling of drainage paths leading fro~
the S~bsite indicate that elevated concentrations of heavy
~etals are n=~ ~igrating off site in significant
concentrations. Sampling also indicated very limited
volatile and se~i-volatile organic contamination of soil at
the subsite (Tables 5, 6). The areas of volatile organic
conta~ination at the Subsite are indicated by the dashed
lines on Figure 4. The volatile organic contamination was
generally limited to the upper six feet of soil. Similar to
the Baier Subsite, heavy metals contamination in the soil
represents the principal threat at the McCarl Subsite based
on the ris}: to sensitive populations, the risk posed through
p=ssitle ingestio~ of vegetables grown in contaminated soil,
a~d the ris}: to possible future residents.
The hydrogeology at the McCarl subsite is similar to
that des=ri~ej for the Baier subsite. There are t~o
un=cnscllda~ed water-bearing units at the site separated by a
relatively thick layer of low-permeability clay till that
significantly li~its the movement of water between the t~o.
As at the Baier subsite, elevated levels of contaminants do
not appear to be present in the lower water-bearing zone.
~ells Y-C-3C, MC-4C, and MC-6C are completed in this zone.
See Figures 5A and 5B for well locations. Wells MC-I, MC-2,
MC-3, MC-4A, MC-5, MC-6, and MC-7 are all completed in the
upper-most ~ater-bearing zone present at the subsite.
Elevated levels of total metals were present in all wells
except MC-l and MC-4A, which are hydraulically upgradient of
the subsite. The direction of ground water flow in this
shallow zone is to the n~rth-northeast.
The analysis for the ground water exposure pathway is
the same as at the Baier site. Due to the low yield and lo~
permeability of the upper water-bearing unit and the
confining layer separating the water-bearing units, a
co~pleted exposure pathway for ground water does not exist at
the site.
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-------
15
6.0 Sucmary of Site Risks
6.1 overvie. of Baseline Risk ~ssessment
A baseline risk assessment was conducted by DuPont to
evaluate the potential impacts to human health posed by site
contaninants in the absence of remedial action (i.e., if the
site were not cleaned up). Both current and future land use
s=e~arios were evaluated. An ecological assessment was also
perfcr7..ed as a conpanion to the baseline human health risk
assess~e~~. EPA conducted a supplemental risk assessment
~hich looke~ at future residential land use scenarios. This
secticn sur.Larizes the findings of these risk assessments
'regarding risks to human health and the environment from
exposure tc conta~inants in the soil and ground water at both
subsites. The co~plete risk assessment is presented in the
RI Report an~ the Supplemental Risk Assessment. Both
docume~ts are in the Ad~inistrative Record. Both risk
assessments consisted of an identification of chemicals of
potential concern, exposure assessment, toxicity assessment,
and risk characterization. -
Cor.~a~:nants of concern (COCs) are contaminants :hat
have been detected at either subsite that have inherent toxic
C~ carcinogenic effects and which are likely to pose the
g~eatest co~ce~n ~ith respect to the protection of human
health a~~ t~e en\'ironment. At the Baier subsite fourteen
co~pou~~£ ~ere identifiej in soil as being of potential
concern. T~o of these are human carcinogens. At the McCarl
subsite, a total of sixteen cor~ounds were identified as
being of potential concern. Two of these are human
carcinoge~s. See Table 6.1 below. Toxicity information fo~
all the che~icals of concern was evaluated including, whe~e
applicable, cancer potency factors and criteria for non-
carcinogen:c effects. For lead, a blood level in children
belo~ ~hich adverse effects are unlikely to occur was
identified.
Table 6.1
contaminants of Concern
Baier site
inorqanics
vola'tile
orqanics
semi-volatile
orq:'\nics
cadmium
chro~iur.:
lead
zinc
arsenic*
seleniur.;
ethylbenzene napthalene
toluene 2-methyl napthalene
xylenes bis(2-ethylhexyl)phthalate
4-methyl-2-pentanone
1, I, I-trichloroethane
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16
t-: :: C =. :- : s i :. ~
ir:c:-==.:,.: C~
vcla~l:'e
c~c=.71iC!;
seIIli-volatile
orqanics
cadr..i U:':'.
chro:,:,.i u;:,.
lea::
zinc
arse:-lic+
1 .
se.enlU::-.
ba~iu;.
copper
manganese
ethyl benzene napthalene
toluene 2-methyl napthalene
~-~ethyl-2-pentanone
>:ylenes
bis(2-ethylhexyl)phthalate
6.2 Toxicity Assessment
The toxicity assessment characterized available huma~
health and environmental criteria for the contaminants of
conce:rr., and qual i tati vely rela':.ed potential chemical
exposu:re (dose) to expected adverse health effects
(resFor.sE~. Included in this assessment are the pertinent
standa=ds, criteria, advisories and guidelines developed for
the protection of human health and the environment. An
explan=.tio;. of ho~ these values were derived and how they are
apFlie:: is p~esented below.
Ca;.=e= potency factors (CPFs or Slope Factors), have
been developed by EPA's carcinogenic Assessment Group for
estim~ting excess lifetime cancer risks associated with
exposure to potentially carcinogenic c~emicals. CPFs, which
are ex~~essej in units of (mg/kg-day)- , are multiplied by
the esti~ated intake of a potential carcinogen, in mg/kg-day,
to pro~'ide an upper-bound estimate of the excess lifetime
cancer ris}~ associated with exposure at that intake level.
The terr.: "upper bound" reflects the conservative estimate of
the ris}:!; calculated from the CPF. Use of this approach
~akes underestimation of the actual cancer risk highly
unlikely. Cancer potency factors are derived from the
results of human epidemiological studies or chronic animal
bioassays to which animal-to-human extrapolation and
uncertainty factors have been applied.
Reference doses' (RfDs) have been developed by EPA for
indicating the potential for adverse health effects from
exposure to chemicals exhibiting noncarcinogenic effects.
RfDs, which are expressed in units of mg/kg/day, are
estimates of lifetime daily exposure levels for humans,
including sensitive individuals, that is likely to be without
an appreciable risk of adverse health effects. Estimated
intakes cf chemicals from environmental media (e.g., the
amour.t cf a chenical ingested from contaminated drinking
-------
17
~a~e=; c~~ be co~pa=e~ te the RfD. RfDs are derived f=o~
hu~a~ e~ije=iolo;ical studies or animal studies to which
~ncertair.~y factors have been applied (e.g., to account fc=
the use e: anir.al data to predict effects on humans). These
uncertainty factors help ensure that the RfDs will not
underes~i~ate the potential for adverse noncarcinogenic
effects to occur.
6.3 Expos~re Assessment
The e>:posure assessment identified potential pathways
and ro~te~ fer conta~inants of concern to reach the receptors
and the e~ti~ated contaminant concentration at the points of
exposure. Exposure pathways by which humans could be exposed
to che=icals of concern were identified based on reasonable
assu~~tions about current and future uses of the subsites.
Direct c~;.~act ~ith the surface soils was evaluated for
hike=s, hunters, and a farmer, assuming these represent beth
currer.t and future land uses. Residential use was also
considered to be a potential future land use.
Centa=inar.t release mechanisms from environmental media,
base= er. relevant hyd=ologic and hydrogeologic informatic~
(fate a~j transport, and other pertinent site-specific
infcrr..a~ier., such as local land or water use) were also
presente~. Potential exposure pathways evaluated include
ingestior. ef surface soils and direct contact with surface
soils. T~e exposure pathway of consumption of small gar.e
fro~ the s:te was also considered. For each potentially
significant exposure pathway, exposure assumpti~ns were made
for reasonatle maximur. exposures.
~ reasonatle ~aximu~ exposure (RME) represents a
situation ~hich is more conservative than an average case but
is not a ~e=st case scenario. As explained in guidance
published by EPA in October 1988 for conducting remedial
investigations and feasibility studies, the RME scenario is
develope~ to reflect the types and extent of exposures that
could occur based on the likely or expected use of the site
in the future. The EPA has established a unique procedure
for evaluating risk due to exposure to lead, which is a
compound of concern at both subsites. The EPA has developed
the Uptake/Biokinetic (UBK) moael to estimate blood lead
levels resulting from exposures to lead. Derived blood lead
levels are then compared to 10 ug lead/dL blood, which the
EPA considers unlikely to re~ult in adverse effects.
6.4 Risk Characterization
The risk characterization quantifies present and/or
potential future risk to human health that may result fror.
exposure to the contaminants of concern found at the site.
The site-specific risk values are estimated by incorporating
information fror. the toxicity and exposure assessments.
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lE
r;;:E:-. s-..::ficiei1t C2.~a are available, two quantitativE
e.alua~ic~s a~e made: the incremental risk to the individ~a:
res~lting frc~ exposure to a carcinogen; or, for
no~carcinogens, a numerical index or ratio of the exposure
dose level to an acceptable reference dose.
6.4.1
Ris~s From Non-Carcinoaenic ComDounds
The EPA has developed standards, guidelines, and
criteria that provide levels of intakes considered to protec~
hu~an populations from possible adverse effects resulting
fro~ che~ical exposures. A ratio of the estimated chemical
intake to the Reference Dose (RfD) provides a numerical
measure of the potential that adverse health effects may
result. This ratio is referred to as the chronic hazard
quotie~t (H~). for noncarcinogenic risks, the term
"significant" is used when the. chronic HQ is greater than
one. When federal standards do not exist, the HQ is compared
to the r.ost applicable criteria or guideline.
Calculated chemical intakes, as described previously,
were cO~~2.re= to che~ical intakes associated with the ~ost
applicable standard or guideline. The estimated chronic
che~ical intake in mg/kg/day is estimated using the exposure
assur.ptions and actual site data. The chemical intake is
then co~pared to the RfD to determine if chronic exposure to
the co~ta~inatec mediu~ presents a risk. Because certain
standards are derived for protection against either
subchronic or chronic exposures, chemical intakes for
noncarcinogens were developed for subchronic and chronic
expos~res and the associated risks were assessed as
appropri2.~e.
Potential concern for noncarcinogenic effects of a
single conta~inant in a single medium is expressed as the
hazard quotient (HQ) (or the ratio of the estimated intake
derived fro~ the contaminant concentration in a given mediu:.
to the contaminant's reference dose). By adding the HQs for
all contaminants within a medium or across all media to which
a given population may reasonably be exposed, the Hazard
Index (HI) can be generated. The HI provides a useful
reference point for gauging the potential significance of
m~ltiple contaminant exposures within a single medium or
across media.
In general, hazard indices greater than one are
associated with potentially increased health risk. The
baseline risk assessment indicated total hazard indices of
15.4 and 3.9 for the Baier and McCarl subsites, respectively.
These calculated indices are associated with the future land
use scenario in which children are exposed to contaminatej
-------
. C
J.-
SU~fc=E ~::: v:a inges:io~ and direct de~cl contact.
Cad~iu~ a~~ c~~c~iu~ are the co~pounds prinarily responsible
fc~ this ris}:. The ris}: assess~ent also indicated that
haza~c in=ic~~ cf 19.6 and 6.~ for the Baier and McCarl
subsites, resp~=~ively, are associated with potential future
adult reside~t ingestion of vegetables grown in cad~iure- and
seleniu~-ccnta~inated soils. A summary of the
noncarcinc;enic hazard indices are presented in Tables 7
throug:: lC.
6.4.2
RiskE Fro~ Carcinoqenic ComDounds
fo~ carcinogens or suspected carcinogens, a quantitative
risk assess~ent involves calculating risk levels considered
to represent the probability or range of probabilities of
developing additional incidences of cancer under the
prescribed exposure conditions. Carcinogenic risk estimates,
expressed as additional incidences of cancer, are determined
by multiplying the cancer potency by the projected exposure
dose level. It.is the carcinogenic potency factor, expressed
in (~g/}:g/day) -.l. v;hich converts the estimated exposure dose
level, exr-ressed in (mg/kg/day), to incremental risk. These
ris}:s ar~ probabilities that are generally expressed in
scientific notation ~e.g., 1X10-f,. An excess lifetime
cancer ris}; of 1x10- indicates that, as a plausible upper
bound, an individual has a one in one million chance of
develo;ing cancer as a res~lt of site-related exposure to a
carcinoge~ ove= a 70-year lifetime under the specific
expos~~e concitions at a site. EPA has determined that
re~edi~l actions should rnini~ize risk to fall within a range
of 10-' to 10-6. In other words, the Agency believes this to
be a gene~a:ly acceptable level of risk.
The carcinogenic risk assessment for the site concluded
that under reasonable maxirnum exposure scenarios there are
no carcinogenic risks associated with waste disposal at the
Site. A summary of the results of calculations of
ca~cinogenic risks evaluated for the site are presented in
Tables 11 and 12.
6.4.3
Risks From Lead
Lead is also a carcinogen but EPA believes that toxic
effects for sensitive populations will occur at lower levels
than those which will produce carcinogenic effects. The EPA
has established 10 micrograms of lead per deciliter (ug/dL)
as a blood lead level in children which is unlikely to result
in adverse health effect. Levels above 10 ug/dL are believed
to result in adverse neurobehavioral effects in exposed
children. Therefore, the EPA assesses potential health risk
from lead by comparing estimated blood lead levels to the
acceptatle level of 10 ug/dL. If blood lead levels exceed 1C
-------
20
u=/c:' a hec.lt:-. ris}: is deeI:led to exist. Hear. lead bloo:::.
levels pre:::.icted by DuPont among resident children at the
sutsites are presented in Table 13. At the Baier subsite,
rnea~ blcod levels were predicted to markedly exceed 10 ug/dL.
At the M=Carl subsite, DuPont predicted that a mean blood
lead of 7.6 ug/dL would result.
6.4.4
Risks from Exposure to Ground Water
To deterr.ine potential effects on human health, path.",ays
by ~hich hu~ans could be exposed were. identified based on
reasonable assumptions regarding current and future uses of
the site. Based on this pathways analysis, it was determined
that no exposure would result from ground water in those
zones conta~inated by contaminants from the site. This was
based on tte lo~ ground water yield from these zones and the
impermeability of the glacial till that makes up the majority
of this zone.
6.4.5
Environmental Evaluation
Environmental and ecological risks associated ~ith the
presence 9f contamination at the site were also evaluated as
part of the risk assessment and were determined to be
mini~21. The ecological portion of the Risk Assessment
deterr..ined that there were no critical habitats or endangered
spe=ies a!fe=~ed by conta~ination present at the site.
6. <4 . £
uncertainties
Regardless of the type of risk estimate developed, it
should be e~phasized that all estimates of risk are based
upon nu~erous assumptions and uncertainties. In addition to
limitations associated with site-specific chemical data,
other assumptions and uncertainties that affect the accuracy
of the site-specific risk characterization result from the
extrapolation of potential adverse human effects from animal
studies, the extrapolation of effects observed at high dose
to low dose effects, the modeling of dose response effects,
and route-to-route extrapolation.
The use of acceptable levels (established standards,
criteria, and guidelines) and unit cancer risks which are
derived from animal studies introduces uncertainty into the
risk estimates. In addition, the exposure parameters used in
estimating chemical intakes are often associated with
uncertainties. As such, these estimates should not stand
alone from the various assumptions and uncertainties upon
~hich they are based. In developing numerical indices of
ris}:, an atteIT.pt is made to evaluate the effect of the
-------
,-
aSS~~F~i2~: a~= li~itations en nu~e~ical estinates. ~h€~ the
css~~F~i~~s a~= un~ertainties out~eigh the ~eaningfulness c:
a ris}: assess~e;.t, a ~~alitative assessment of risk is
~er:orr..e=.
6.4.7
Conclusion
In con=lusion, based on the results of the risk
assess~e~t, EPh has determined that actual or threatened
release£ c: hazardous substances from this site, if not
rernediate= ~y the preferred alternative or one of the other
active ~eas~res considered may present a current or potential
threat to p~tlic health, welfare, or the environment.
7.0 Descriptic~ of Alternatives
~ t=tc: c: eight alternatives were evaluated in detail
for rewediation of the site. One alternative addresses
ground ~ater contamination. The remaining alternatives.
address seil contamination.
7 . 1
Grou~:
~ater
The baseline risk assessment conducted for ground water
indicate~ that ground water contamination posed no threat to
huma~ he=ltr. because there was no completed exposure pathway
at thE fa::lity. Ttis conclusion was based on the low yield
frc~ the c2~ta=i;.ated water-bearing unit at the site and the
Frese~=e c: a confining unit below the water-bearing unit.
This confining layer is 75 feet thick and consists of a low
perrneatility glacial clay till. The yield from the water-
bearir.~ u~it is in the gallons-per-hour range: househcld USeS
re~~ires a ~iniwurn yield in the gallons-per-minute range. o~
the basis of these two factors, therefore, only the no actic~
alternative is described below.
7.1.1
No Action
The no action alternative would not involve any action
to prevent or reduce exposures to ground water contamination
as the likelihood of such exposures has been judged to be
remote. Monitoring will be conducted to verify that no
exposures resulting from the conditions at the site occur in
the future.
Ground water samples will be collected from existing on-
site monitoring wells and analyzed for volatile organics and
total metals. Sampling will initially be conducted on a
quarterly basis during the first year and would be
subsequently be conducted on a semi-annual basis for the next
fo~r years.
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22
Du~in~ the statutory five-year revie~, the five yea~~ c:
g~oun= ~cte~ monito~ing data and other information, includi~~
site conditions ~ill be evaluated. If, upon completion of
the five-yea~ revie~, it is determined that the site does net
p~esent a threat to health or the environment monitoring
could be te~.inated and the site deleted from the NPL.
If the five-year revie~ indicates continued monitoring
is necessary to ensure that no exposures, occur, monitoring
~ill be con~inue= for an additional five years and a second
revie1n° pe~formed.
If, ho~ever, the five-year review indicated that
exposures are occurring, the need for remedial action
in=luding treatment or other controls will be evaluated.
There are no federal or state ARARS for the no action
al~ernative. Compliance with federal and state ARARS is not
required as no remedial action is necessary to protect human
health a~d the environment.
Costs fo~ the no action alternative would include costs
for the collection and analysis ~'f ground water samples. The
total present worth of the no action alternative, assuming a
te~ yec~ monitoring program as described above, is estimated
to be S19~,OOO. '
7.2 Soil Remedial ~lternatives
~he baseline risk assessment for soils indicated the
pc~e~~ial fc~ a significant health threat to humans. Heavy
metals conta~ination in the soil represents the principal
threat at the County Road X23 site based on the risk to
sensitive populations, the risk posed through possible
ingestion of vegetables grown in contaminated soil, and the
risk for possible future residents. Therefore, a full range
of alternatives for metals contamination in soil was
evaluated as described below.
7.2.1
No ~ction (Alternative 11
The National contingency Plan requires that the "no
action" alternative be evaluated for every site. This
alternative provides a baseline for comparing the
effectiveness of the other remedial alternatives. Under this
option, no further action would be taken at the site to
prevent exposure to contaminated soils or migration of
conta~ination from the site. The site would remain in its
present condition. There would be no costs associated with
this alternative. This alternative would not comply with
ARhRs .
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23
7.2.2
Institutional Controls (Alternative ~
This alternative ~ould include implementation ef access
restrictio~s (fencin;) and deed restrictions to limit and/or
control future use ef the site. This alternative would not
meet the Io~a ARAR requiring Responsible Party Cleanup
Actions (I.A.C. Chapter 567-133) to address soil
eonta=inatien which may affect ground water, nor would it
meet the CERC~. preference fer treatment to reduce the
toxicity, r.obility, or volume of hazardous waste.
Because this alternative would result in contamination
remaining on the site, CERCLA requires that the site be
reviewed every five years. If justified by the review,
re~edial actions would be implemented at that time to remove
er treat the ~ast€s. It would also not meet Iowa's
req~ire~e~ts fer closure ef existing solid ~aste landfills
(I.h.C.Chap~er 567-103).
7.2.3
Institutional Controls, Clay and Soil Ca~
(Alternative II
Cnder t~is alternative access restrictions (fencing),
deed restrictions, and a compacted clay cap would be
utilized. The clay cap would meet requirements of the State
0: Iowa for closure 0: existing solid waste landfills (I.A.C.
Cha~t€r 5~I-I03) and all other identified ARARs.
Specifically, in this alternative a two-foot clean soil
cover would be established over the two-foot compacted clay
ca~. The clay ~ould be compacted to a permeability of 10-'
ce~timeters per second or less. Following construction of the
cap, vegetation would be established to prevent erosion.
Restrictions on the use and development of the site would be
required to ensure the integrity of the cap.
This alternative would require long-term maintenance and
~onitoring. Site inspections would be required on a regular
basis along with maintenance of the cap. Sampling of
existing monitoring wells would be conducted to monitor
ground water quality.
The time required to implement the capping remedy is
estimated to be approximately 18 months. The present worth
cost is estimated at approximately $1,800,000. The major
capital cost component is cap construction at $710,000.
Because this alternative would result in contamination
remaining on the site, CERCLA requires that the site be
reviewed every five years. If justified by the revie~,
remedial actions would be implemented at that time to remove
or treat the ~astes.
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2~
7.2.4
Institutional Controls. Multi-Me~ia Cap {~lternative !J
Ttis alternative involves the use of institutional
controls and a ~ulti-media cap. The multi-media cap would
consist of alternating layers of compacted clay, geotextile
ffiaterials, and a clean cover soil. The multi-media cap would
be less susceptible to damage and would be more protective
tha~ the clay and soil cap discussed in 4.3. The multi-medi~
cap ~ould also be more effective in isolating contaminants
:ro~ exposure to the environment. This alternative would
meet identified ARARs.
Follo~ing construction of the cap, vegetation would be
established to prevent erosion. Restrictions on the use and
develop~e~t of the site would be required to ensure the
integrity of the cap.
This alternative would require long-term maintenance a~d
monitoring. Site inspections would be required on a regular
basis along ~ith maintenance of the cap. Sampling of
existing monitoring wells would be conducted to monitor
ground ~ater quality. A Five-Year Review, as discussed in
7.2.3, ~ould also be required.
The tipe required to implement the multi-media capping
re~edy is estimated to be approximately 18 months. The
Frese~t ~~rth cost of the alternative is estimated to be
apFrcxirately $2,000,000. The major capital cost co~ponent
is cap construction at $920,000.
7.2.5
Excavation. Off-site Disposal in RCRA Lan~fill
(Alternative ~
Contaminated soil would be excavated and transported to
a RCRP.-authorized landfill. Following excavation, the site
would be graded and vegetation would be established to
prevent erosion. All Department of Transportation
regulations applicable to transportation of hazardous waste
~ould be observed. It is estimated that 14,200 cubic yards
of soil would be removed from the site. This alternative
would have to meet RCRA Land Disposal Restrictions.
The time required to implement the off-site disposal
remedy is estimated to be approximately 150 days. The
present worth cost is estimated at approximately $8,000,000.
7.2.6
Excavation. Treatment. Off-site RCRA Landfill
(~lternative !L
This alternative is the same as 4.5 except treatment of
the hazardous waste is added before disposal in a RCRA-
authcrized hazardous waste landfill. The type of treatL.ent
-------
2S
\-;0:.11 = 1 i}:e2 y be dictated by reg-..:irements of the RCRA Land
2isp~5a~ ~es~rictio~s. This alternative ~ould have to mee~
all l-.F.J.:i.S.
Th~ ti~E to complete this alternative is the same as
alternative 4.5 since all treatment would be off-site. The
present ~orth cost is approximately $10,700,000.
7.2.7
statilization/Solidification (Alternative 11
This alternative involves the in situ (in place)
statiliza~ion/solidification of the contaminated soil.
Initially, surface debris not amenable to solidification
would be removed from the site and transported to an RCRA
authorized hazardous waste landfill. Then, solidifying
agents (ce~ent-like materials) and water would be injected
into the ccnta~inated soil, which would be mixed with large
augers to ottain a uniform mixture. The mixture would set uF
into a solidified matrix. Following stabilization/
solidification the soil mass would be covered with clean soil
to prevent human and environmental contact and to protect the
solidifiej ~ass. This alternatjve would meet all ARARs.
follo~ing construction of th~ soil cover, vegetation
~ould be estatlished to prevent erosion. Restrictions on the
use a:-:j oevelopr..en":. of the site would be required to ensure
the i~t€~rit) of the cover and the solidified soil mass.
This alternative would require long-term maintenance and
monitcr_ng. Site inspections would be required on a regular
basis along with maintenance of the cover. Sampling of
exis~in~ r.cnitoring wells would be conducted to monitor
grour.j ~ate= quality.
The ti~e required to implement the in situ
stabilization/solidification remedy is estimated to be
approximately twelve to thirty-six months. The present worth
cost is estimated at approximately $1,400,000. The major
cost component is the construction at $1,200,000.
Because this alternative would result in contamination
remaining on the site, CERCLA requires that the site be
reviewed every five years. If justified by the review,
remedial actions would be implemented at that time to remove
or treat the wastes.
8.0 Summary of Comparative Analysis of Alternatives
Nine evaluation criteria have been developed by EPA to
address CERCLh statutory requirements and technical, cost,
and institutional considerations which the Agency has
deterr..ined appropriate. The evaluation criteria serve as the
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26
basi5 fer co~j~oting detailed analysis during the FS and for
s~bse~~e~~ly seleoting an appropriate remedial actic~.
~~~a=~~E~~ ~ pro\'ides a glossary of the evaluation criteria.
The preferred alternative for the cleanup of
ce~ta~inated soils at the County Road X23 Site is in situ
solidification/stabilization. Based on current information,
this alternative appears to provide the best balance among
t~e alter~atives with respect to the evaluation criteria.
T~e preferred alternative is described below in relation to
thE evalu:tien criteria and is compared to the other
alter~atives under each criterion.
8.1 Ground Water
8.1.1
Overall Protection of Human Health and Environment
V~ilizin9 the baseline risk assessment, EPA has
deter~ined that ground water contamination does not pose a
threat to human health or the environment. Therefore, no
remedial action is necessary to protect human health and the
enviro~~er.t. EPA's decision is the result of consideration
of th~ fcllo~ing factors: the very low yield from the
conta~inated water-bearing unit at the site, and the presence
of a 75 foet thick confining layer below the water-bearing
uni~. ~or.itoring will be conducted to verify that no
exposure to ris}:s posed by conditions at the site occur in
the f~~~re. Cc~~liance with federal and state ARARs is not
re~~irej as ~o remedial action is necessary to protect human
health or the environment. Furthermore, development and
ca~parison of remedial alternatives is not necessary, because
no unaoceF~able risks are presented by the groundwater.
8.2 Soil
8.2.1
Overall Protection of Human Health and Environment
The preferred alternative for soil is to
stabilize/solidify all contaminated soils with contaminant
concentrations above the cleanup levels specified earlier.
Stabilization/solidification of the contaminated soils would
reduce direct contact exposure to protective levels and also
minimize the potential for contaminant migration.
With the exception of the no action alternative, all of
the alternatives provide protection of human health and the
environment by removing, reducing, or controlling risk
through treatment, engineering controls, or institutional
controls. The no-action alternative will not be evaluated
further since it is not protective of human health and the
environment.
26
-------
27
8.2 . ~
Co~~liance With ARARS
ThE F~E:e~~e~ altErnative ~ill co~ply ~ith all federal
and state ~.S. There are no relevant chemical- or
location-specific ARARS. Major action-specific ARARS ~hich
the preferred alternativE will comply with include: RCRA,
Iowa Responsible Parties Cleanup Regulations (Title X,
Chapter 133), DOT Regulations for transport of hazardous
~aterials, and the Occupational Safety and Health Act.
The ins~itutional controls alternative would not comply
~ith ARhRE. The other alternatives would have complied with
their respe2tive ARARs which include regulations from RCRA,
including the Land Disposal Restrictions, and the Clean Air
Act.
8.2.3
Lonq-Term Effectiveness and Permanence
ThE ir.plementation of the stabilization/solidification
alternative for all soil above cleanup concentrations would
effectively eliminate the long-term risks associated with
direct conta=~ and potential contaminant migration at the
Coun~y Roaj X23 Site. The mobility of the contamina~~s ~ould
be reduced through bonding to the solidified matrix and
through reduction in the surface area exposed to ground or
surfacE ~ate~. By providing treatment to reduce mobility
~ith ~aintEnance and monitoring, the preferred alternative
should adequately p~event migration and direct contact.
Long-ter::. co:-:trols \t.ould be required to ensure the integrity
of the alternative.
The Alternatives Two, Three and Four would reduce but
net el ir..ina te long-terr.. risks at the Site. Long-term
controls would be required to ensure the integrity of the
cap. Alternative Five would eliminate the on-site long-terr.
risks associated with the contaminated soil. Alternative
Four would net eliminate the long-term risk associated with
the contar.inants themselves, but would eliminate the long-
term ris}~ at the site.
8.2.4
Reduction of Toxicitv. Mobilitv. ~ Volume
The preferred alternative would employ treatment to
reduce the mobility of the hazardous constituents in the
soil. The toxicity would not be affected.
Alternatives Two, Three', Four and Five would not satisfy
the CERCLA preference to reduce toxicity, mobility, or volume
through treatment. Alternative Six would reduce the
toxicity, mobility, or volume depending on the treatment
option selected.
-------
28
8.2.5
Short-Te~ Effectiveness
'The short-tern ris}:s associ.ated with the preferred
alternative include surface runoff and worker exposure to
co~tar.inants as well as possible exposure to fugitive dust.
'These potential exposures can be effectively minimized and
controlled by compliance with the action-specific ARARS and
implementing engineering controls such as dust suppressants.
The~e would be no short term impacts associated with the
institutional controls alternative. All the other
alternatives would present the same short-term risks
identified above in relation to on-site construction,
excavation and loading. As noted above, compliance with
ARARS and implementation of engineering controls would
effectively minimize and control the exposures.
8.2.6
Imp1ementabi1itv
Implementation of the preferred alternative would
involve r.onventional solidifica~ion technologies that are
prove~ an5 reliable. There are no anticipated significant
ad~ir.istrative issues, such as permitting, that should affe=t
the irnplernentability of this alternative.
Implementation of the other alternatives would also
involve conventional technologies that should not represent
any te=hnical or ad~inistrative impediments to their
implementation.
8.2.7
Cost
The present worth cost of the preferred alternative
would be approximately $1.4 million. The present worth cost
of Alte~natives Three and Four would be approximately $1.8 to
2.0 million. The present worth cost of Alternative Five
would be approximately $8.0 million and Alternative Six would
cost approximately $10.7 million.
8.2.8
state AcceDtance
The State of Iowa concurs with EPA on the preferred
alternative for the cleanup of contaminated soils at the
County Road X23 Site.
8.2.9
community AcceDtance
Community acceptance of the stabilization/solidificatic~
alternative has been evaluated following the Public Meeting
held on April 18, 1991, and conclusion of the public comment
period on May 11, 1991. The results of this evaluation are
presented in the attached Responsiveness Summary.
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29
9.0 Selecte~ Re~edy
9.1 Grounc ~atcr
Based o~ the Baseline Risk Assessment and Supplemental
Risk Assess~e~~, EPA determined that ground water
contamination does not present a threat to human health and,
the~ef~re, nc re~edial action is necessary. EPA's decision
~as based C~ c~nsideration of the following factors: the lo~
yield of the ~ater-bearing unit at the site and the presence
cf a th:ck (7S-foot) confining layer below the water-bearing
unit. Y.~r.itoring will be conducted to verify that no
exposures to risks posed by site conditions occur in the
future. Co~pliance with federal and state ARARs is not
required as no remedial action is necessary to protect hurnar.
health or the environment. Furthermore, development and
co~pa~isc;. cf re~edial alternatives is not necessary, because
no u~acceFtab2e risks are presented by the groundwater.
9.2 Soil
Based C~ an evaluation of the relative performance of
eac~ alterr.a~ive ~ith respect to the evaluation criteria, EPA
has deter~inej that stabilization/solidification presents the
best bala;.ce aL.ong the alternatives considered for cleanup of
conta~inated soils.
[F~ be2ieves that this alternative would satisfy the
sta~u~~~y req~ire~ents in CERCLA Section 121, which are: to
be protective 0: human health and the environment: to COL.ply
~ith feje~al and state requirements that are legally
apFlica=2e or relevant and appropriate for the alternative;
to be Ccs~-effective; and to utilize permanent solutions and
alternative treatment technologies or resource recovery
technologies to the maximum extent practicable.
The preferred alternative would stabilize/solidify all
soils contaminated above health based levels into a solid
monolith such that hazardous waste would be unable to leach
into the ground water. All surface waste materials not
amenable to the technology would be removed and disposed of
at an off-site RCRA hazardous waste landfill prior to the in
situ stabilization/solidification. These actions would
eliminate the potential for contaminant migration. Following
stabilization/solidification the monolith would be topped
with a soil cover to protect the monolith and prevent direct
contact. The protective cover would be graded and planted
with vegetation to prevent erosion. Restrictions on the use
and development of the site would be required to ensure the
integrity of the cover and the solidified soil mass.
Additionally, the preferred alternative would not pose any
unacceptable short-term risks during the implementation of
the remedy. Finally, the preferred alternative is the lowest
cost for cleanup of contaminated soils of all the protective
alternatives evaluated for this Site.
-------
30
~he F~efe~~ej alternative would corply with I.A.C
C~aF~e~. :~/-133 ~~ic~ re~ires remedial actions in the State
c: Io~a t~ ajdress soil contamination that may adversely
a:fect g~ou~j ~ater. The preferred alternative would also
~tilize per7..ane~t solutions and treatment technologies to the
~axi~u~ e>:tent practicable. The determination of the maxi~u~
extent to which permanent solutions and treatment can be
practically utilized takes into consideration a number of
factors including long-term and short-term effectiveness of
the alte~na~ive, implementability, and cost.
Protective contaminant concentrations were determined
for several contarninants of concern at the site. The
protective concentrations are based on the conservative
residential exposure scenarios for both an average and
maximuw cas~. The protective soil concentrations were
deterrc.inej to represent a reasonable maximum e~osure.
DuPont has proposed a cleanup level for lead in soil of 350
parts per ~illion(pp~). The UBK model confirms that this
level would be protective of over 95% of potentially exposed
children (the sensitive subpopulation). For chromium, the
protective contaminant concentration was developed by
estirnating the concentration that would result in a hazard
quotient of 1.0 fcr each exposure pathway (i.e., dermal
exposure, ingestion, etc.). The resulting cleanup level was
150 pp~. For cadrnium and selenium, cleanup levels were
prcpose= by the Agency for Toxic substances and Disease
Regist~y. These levels are 20 pp~ and 10 ppm, respectively.
10.0 statutory Determinations
Under its legal authority, EPA's primary responsibility
at Supe~funj sites is to undertake remedial actions that
achieve adequate protection of human health and the
environment. In addition, Section 121 of CERCLA establishes
several other statutory requirements and preferences. These
specify that when complete, the selected remedial action for
this site must comply with applicable or relevant and
appropriate environmental standards established under federal
and state environmental laws, unless a statutory waiver is
justified. The selected remedy also must be cost effective
and utilize permanent solutions and alternative treatment
technologies or resource recovery technologies to the maximu~
extent practicable. Finally, the statute includes a
preference for remedies that employ treatment that
permanently and significantly reduce the volume, toxicity, or
mobility of hazardous wastes as their principal element. The
following sections discuss how the selected remedy meets
these statutory requirements.
-------
31
10.1 prote=ticr. of H~an Health and the Environment
T~E sElE:tej re~edy protects human health and the
en\'i~c~~E~: t~~ough stabilization/solidification of the
c:n~a~:nated s::l into a solid matrix that will bind and/or
ent~~~ t~e c:~ta~inants thereby immobilizing them and
prevent in; any future releases.
Stat:lization/solidification will also eliminate any
direct con:a:t threat, and threats posed to future
residential or agricultural users of the site or adjacent
land a~eas. ~o site contaminant related cancer risks were
identified. By preventing direct contact and immobilizing
the conta~inants, the Hazard Indices (HI) would be reduced to
less than onE. This level of HI is within an acceptable
range. The~e are no short-term threats associated with the
selectEd re~2~Y that cannot be readily controlled. In
ajjit::~: n2 adverse cross-media impacts are expected fror.
the re~ej;.
10.2 Compliance with Applicable or Relevant and A~~ro~riate
Requirements
The prefe~~ed alternative wC~lld comply with all federal
anj statE AF~~5. There are no identified chemical-specific
C~ l:=~:i:n-s?ecific ARARS.
:tE F~Efe~red alternative would comply with I.A.C
ChaptEr 567-122 which requires remedial actions in the State
of Io~: to address soil contareination that may adversely
affec: g~cunj water.
10.3 Cost-Effectiveness
The selected remedy is cost effective because it has
been determined to provide overall effectiveness proportional
to its cost, with the net present value being approximately
$1.4 ~illion. The selected remedy is the least costly of
remedies that were judged to provide equal protection of
human health and the environment. This included all remedies
exceFt the no-action and institutional controls alternatives
for contar.inated soil.
10.4 Utilization of Permanent Solutions and Alternative
Treatment (or resource recovery) Technoloaies 12
the Maximum Extent Practicable (KEP)
The State of Iowa and the EPA have determined that the
selected rer:edy represents the maximum extent to which
permanent solutions and treatment technologies can be
utilized in a cost-effective manner for the DuPont County
Road >:23 site. Of those alternatives that are protective of
-------
32
hU:7.a:-. health and the environr..ent and cor.ply "..ith ARARs, thE
S~a~c of Io~2. and EPA have determined that this selected
re~.edy provides the best balance in terms of long-tern.
effectiveness and permanence, reduction in toxicity, mobility
or volu~e achieved through treatment, short-term
effectiveness, implementability, and cost. Also, the State
and EPA considered the statutory preference for treatment as
a principal element, and considered input from the community
ar.:: the state.
This alternative reduces the mobility of contaminants ty
treat~ent, complies with ARARs, provides short-term
effectiveness, and protects human health and the environment
equally as well as Alternative Six. Alternatives Two, Three,
Four and Five do not meet the preference for treatment. In
terr.s of long-terr. effectiveness Alternative Seven provides
protection equal to or exceeding all other alternatives.
Also, Alternative Seven will be easier to implement
administratively because it requires less coordination with
relevant agencies. The selected remedy is reliable and can be
ir.plemented quickly once treatability testing is completed
~ith less difficulty and at less cost than other treatment
alternatives. It is therefore determined to be the most
appropriate soluti~n for th~ con~aminated soil at the DuPont
County Road X23 Site.
10.5 Preference for Treatment as ~ PrinciDal Element
By treating the contaminated soil to stabilize/solidify
it, the selected remedy addresses the principal threat of
futur~ direct contact and ingestion/inhalation of
conta~:nated soil. Therefore, the statutory preference fer
remedies that employ treatment as a principal element is
satisfie::.
11.0 Documentation of Significant Changes
The Proposed Plan for the E.I. du Pont De Nemours and
Company County Road X23 Superfund site was released for
public comment on April 11, 1990. The Proposed Plan
identified Remedial Action Alternative Seven,
Stabilization/Solidification, as the preferred alternative.
The EPA reviewed all comments received during the pUblic
comment period. Upon review of these comments, it was
determined that no significant changes to the remedy, as it
was identified in the Proposed Plan, were necessary.
-------
TABLE 1
Chemi::als 01 Potential Concern in Surficial Soil
(m~'J.g)
BAIER SUS-SrTE
Anal)"lE
RangE
Mean
Med:a~
''''
Arae~i=
2.70
-
23.40
d7.12
4&.55
Cadmium
5.~:j
-
510.00
171.48
171 ;75
d
.-
1830.00
706.68
.d
Chromium
15.10
695.50
...
. .
':':"~:U.37,' .,
. ."
Selenium
0.75
-
53.50
.16.8
. .
lea:
6~.O:
-
38950.00
17012.90
18200
Zinc
, OS.O~
-
29800.00
8461.40
578
S:>;,..II:,::: ,.~:~ ~-4 ."\: ~.s, Re 'T\O\'a , A:M~, Work Plan, Saie' Sill, Oc:1oD'~ 27, 1969 and TaDle 4.'.'2.
F,r.i Re'T\&:::,a InvaS'ugalion Report tor Baier Sill and M:Carl Sit., January 16, 1eg,.
...1&----'
-------
Table 2
Volatile Organics
Baier Site
Soil Samples
May 1990
(m;fkg)
AnalYte RANGE MEAN MEDIAN
Toluene {0.S}ND-4.8 :1.401 .1.0
...
Ethylbenzene (0.5)ND-14 ..6.492 7.3
. .
Total Xylene (O.5)ND-67 34.736 ~
Acetone (1.'}ND-12 4.0 2.1
.
Methylene Chlorioe <1.9)NO 0.95 0.95
2-Butanone 1.36J-(3.9)ND "'.625 1.625
Notes:
ND() - not detecte::j at concentration indicated in parenthesis.
J - indicates an estimated value.
S - indicates analyte found in the associated blank as well as the sample.
Mean and median calculated by using one foot of the detection limits
for samples where no compound was detected.
- Oilly dete:te::1 volatile organics are listed. All $8mples analyzed for CLF
volatile organics per the contract laboratory statement of work.
.
-------
Table 3
Semi-Volatiles
Baier Site
Soil Samples
May 1990
(mg/kg)
Ans!l!e FlANGE MEAN MEDIAN
Benzoic Acid 0.17J~.OJ 1.565 .. . :,jj" ......
bis(2-Ethylnery!) ~htr-,a: a: E O. '~-(' .S)NO 0.321 0.1975
Napthalene 0.1 9J-6.50J 148.669 '..345
2-Meythyna;!thalene 0.048J-(1 5~O)NO . 1 50.865 30.25
Oi-n-BLltylphtnaia te 0.064BJ-{1S)NO 0.272 'D.OS7
Oi-n-OCty1phthalate (O.3S)NO-{O.41 )NO 0.1975 0.1975
Notes: NO() - nt"l: dete:::1ej at concentration indicated in parenthesis.
J - indicates an estimated value.
S - indl:ates a~alyte found in the associated blank as well as the umpre.
- Maar; and median calculated by using one-half of the deteCtion limits
for samples where no compound was deteCted.
-------
TABLE 4
Chemicals of Potential Concern in SurficiaJ Soil
McCARL SUB-SITE
Ana'yie
Anse-niC
Bartum
Cadmium
Chromium
Coop*-
LM2
. Manganes*
Selenium
Zir:
Ranee
O20 - 16.5
473.00 - 7410.0
1.W - - —443.0
17.20 - 407.0
10.50 - 1410.0
281.00 - 3563.0
604.00 - 2560.0
0.22 - 177.0
357.00 - .6020.0
Mean
«
':• &69
" ,a$S6Jt' 7
T^'^aie;;.
-;••;: 505.e4"':.
135J3
1314.04
1321.41
11.43
1W9.96
M«diin
5.8
; ' •' 2140
/ :-S<-6
'.".' •'*7-1 ,
CZ5
1280
.1260
4J
1660
SOURCE: Table 4.3-8, Final Rem»dia! Invtstipation Report (or th» Bai«r 8it«
ana the McCan Site. January 16,1931.
NO - Not Detected at concentration noted.
6 - Reported value is less than the contract required detection limit (CPOL)
but preaier than the instrument oetection limit (IOL).
-------
Table 5
Volatile Organics
McCart Site
Soil Samples
May 1990
(mgfkg)
AnalYtE RANGE MEAN MEDIAN
....- "... .'
Toluene (O.32)ND-15 '4.328 0.7$
. .
Ethylberuene 0.04i-36 " .791 5.7
Total Xylene 1.8-200 65.225 21.0
.
Acetone (O.032)ND-(0.8)ND '6.765 2..44 5
Methylene Chloride O.016-(0.')ND 0.27 0.016
2-BUtanone 0.04aJ-9.6SJ 3.237 0.9
4-Methy-2-Pentanone C.072-(' .6)N~ .557 C.S
Notes:
N:>() - not deteCte~ 2.t concentration indicated in parenthesis.
J - indicates an estimated value.
S - indicates ana!yte found in the associated blank as well as the sample.
- comp:)unds Identified during a re-analysis of a diluted lample.
- compounds whose concentrations exceed the calibration range of the
GC/MS instrument for this specific analysis.
- Mean and median calculated by using one foot of 1he detection limits
for lamples where no compound was detected.
.IE' tLA/IfCS'.:I1 ,,,,.,.. fa .. ,
-------
Table 6
Semi-Volatiles
McCart Site
Soil Samples
May 1990
(mglkg)
AnalytE F\J..NGE MEAt~ MEOIA~
Benzoic Acid 0.12J-{1.9)NO.. 0.426 .. .0.30
.'" .. ...
bI1{2-Ethyll'lexyf)Phthalate .. '" . .... ..Q.23 ..
O.086J-(25)NO :D.265...
...-," . 0"
.. .. ...~.3S
Napthalene 0.14J-(2S)NO " 3.335
2-Meythynapthalene 0.81J-(2S)NO 3.55 ..0.61
Pentachlorophe~o1 0.17 J-(1.6)ND 0.735 . 0.735
Ot-n-ButytphthaJate (O.40)NO-(O.42)ND 0.205 0.205
Notes: N:)~) - no! de!e:ted a~ concentration indicated in parenthesis.
J - indi:ates an estimated value.
B - indicates analyte found in the associated blank as well as the sample.
- Mdn and median calculated by using one-half of the detection limits
for $a:TI~les where no compound was detected.
-------
Chrm 11::2 !
et1U:E': Ht":Er,
. ~U.~ Pa'r,'II.i!\'
Anenic
Cacim.ium
Chromium \1
ScJeniw:
TAB~ 7
Sl ~1. \L\RY or CH R O~ 1 C H.U.AJU> [!'\1)[X ESTIMA n:.s
FOR CLlUU:~'" SITE '1SITORS
CDI
(mli! 'k1>-de')
1~~!;t;~~; c! S~:'
3.9 x 1~
7.3 x 10'""
3.6 x 1~
1.lxlC-'
BAlER SUBSITE
CDI
AdJa.sted lor
Ab!orntlon
No
No
No
1'0
Exnosur~ P2~r.'II.'!\" D~~2' Con:a:t v.;!h SC'il
Arsenic
Cacim.ium
Chromium \1
SeJeniw:
~.8 % 1()"9
8.8 x IC~
~.4 x 10'"
1.4 x IO~
E~cu~~ P2~!,:\I.'2\'
Ct~RE'''' Hn:EF. (~:..~\
In~~~!i~r. c~ s~:r
Arseni ;
Cadmium
Chromium \1
Selcniu:::
1.0 x lC'.('
V; x lJ'S
9.4 x 10.5
1.0 x 10.5
Yes
Yes
Yes
Yes
RID
(m2/b-c!n1
1 s 10'"'
1 s 10-3
5 s 10'"'
3 I 10'"' .
Subtotal (pathway)
911~
6 I 10"5
1110""
2 I 10.3
Subtota1(Pa1hway)
Current Hunter Tota] Chronic Hazard lDdcx
1'0
No
No
No
EX!X)cur~ Pa!h\l."2\- D~~2' Conra:'t v.;!h SQil
Arsenic
Cadmium
Chromium VI
Selenium
.,u\~nT'WS042$
1.2 J 10-1
2.3 110'"
1.2 J 1~
3.6 J 10-1
11 10.3
11 10"
5 I 10'"
3 J 10.3
Subtotal (pllhway)
9 110""
6 s 10'"5
ls1~
2 I 10'"
SubtOll1 (pa1hway)
Current Hiker (child) Tow Chronic Hazard lDdu
Yes
Yes
Yes
Yes
1
Huard
Oaotlfnt
0.0m4
0.cm7
0.cm7
O.oo:n4
0.002
O.axxxlS
0.002.
0.00.-
O.ooxxAS
0.006
0.008
0.001
0.02
0.02
0.001
0.042
0.«xm2
0.006
om
0.«xm2
0.D26
0.06
-------
TAB~ 7
Sl~!MARY or CHRO~1C HAZ.AJU) ~"DtX ESTlMATES
FOR CUJUU:~" SIn \'lSITORS
BAIER SUBSm:
(CoatiDuedl
Cbtmlc:z!
CDI
{mr./k.2-d!'"
CDI
AdJusted for
AMorntion
CL1UtE'j It 'YE''TI.E Ht. ~i'EP,
~ure Path'!,-
In~e~!i~n o~ S~i]
ArKDic:
Cadmium
ChromiWD \1
Selenium
5.5 I lcr'
1.0 I 10.5
5.0 I 10.5
1.0 I 10.5
No
No
No
No
E~~u~~ PathlA,!\- D~~a' ConlaC': v.ilh Soil
Arsenic:
Cadmium
Chromium \ 1
Sdeniwx:
6.7 110~
1.2 I 10~
6.1 x 10<
2..0 I 10.7
Yes
Yes
Yc.s
Yes
RlD
(m2/k.2-dn)
11 10'"'
1 I 1(""
5 1 10"'
3110'"
Subtotal (pathway)
911~
6 z 10"'
11 1crC
2 z 10"'
SubtOt&1 {path WI),)
ClTRRE'i HIKER (E!:>TELE.S)
CWTent Juvenile Hu.nter Total Chronic Hazard mdc:.x
E~o(ure Pa'hW2\-
'n~~"tiC\r. (\~ S~~l
Huard
Oaotient
o..cm.s
0.01
0.01
OlW5
0.021
0.cxm7
om
.0.06
O,OO'X)8
0.08
0.10
Arsenic: 3.8 x 10" No 1 z 10" 0.(0)4
Cadmium 7.0 I 10~ I'o 11 10" 0.007
Chromium VI 3,4 x 10.5 No 5 1 10.3 0.007
Selenium 1.11 10~ No 3 Z 10"3 0.(004
SubtotaJ (pathway) 0.01.5
E~ure PathlA'2'- Dermal Cont8c=t ".;th Soil
Arsenic 7.iJ 110'" Yes 9 I lo-t 0.00xn8
Cadmium 1.4 1 lcr' Yes 6 1 lcr' '0.002
~omium VJ 7.111cr' Yes 111~ 0.007
Scl:Dium .2.2 110-1 Yes 2 I 10'" 0.
-------
ChrmlO!!
TABLE 7
SUM~1.~Y or CHRO~lC IU.Z.ARD 1~1)EX EST'lMA1T.S
FOR Cl:RR£..',-r sm '1StTORS
CDJ
(m£ I~-de')
~ure Pa!hv.'2'-
Ct.TRRE~'i HIKER (YEAR ROt~"D)
r"'~~~tio~ 0' So!!
An=ic
Cadmiw::
Chromium VI
SeLenium
U 1 lC-'
5.2 1 10<
2.6 1 10.5
8.2 I 10"
E~cu~~ Pa!nv.°2\- D~~a1 Con:a~ 1P-;th C;r"\i~
Arsenic
Cadmiw::
Chromiun: \1
Seleniu:
Ct1=:RE''i fAR'.ITF.
E~cure Path\l,'2'-
Anenic
Cadmium
Chromium VI
xlenium
3.4 J 1~
6.4 X 10.'
3.2 x 10~
..
1.01: 1(J'
BAIER SUBSIT£
. (CoDtiDUed)
CDI
Adjusted lor
AMOnltiOD
No
1'0
No
No
Yes
Yes
Yes
Yes
IUD
Im2.fIcR-d8")
1 J[ 10"'
1 x 10'"
5 J[ 10'"
3 J[ 1(r'
Subtotal (pathWl)')
9s1~
6 S 10.5
lxl~
:2 I 10.3
SubtoW (pathv.'I)'}
Current Hiker (Yur Round) Total Chronic Hazard lD~x
In~~stion cr Soil
1.7 J 1~
3.11 10.5
1.6 x 10~
4.9 1 10~
~sure Pathv.'2'~ Derma1 Cont8~ "..;t}j Soil
Arsenic
Cadmium
Chromium VI
Selenium
JU\~1\T'OJ$&:=
3." I 10-1
6." 1 leT"
3.2 I 1~
1.0 110""
1'0
No
No
No
Yes
Yes
Yes
Yes
11 10"
1 x 10.3
5 J[ 10"
3 Z 10"
Subtotal (pathway)
9 Z 10-4
6 s 10.5
1 Z 10-4
:2 Z 10'"
SubtouJ (pathway)
Current farmer Tot&] Chronic Hazard lDdex
3
Huard
Ouotitt1~
oron
0.005
0.005
0.
0.002
0.03
0.03
0.002
0.06
0.£QX)4
0.01
0.03
OlXOO4
0.04
0.10
-------
TABLE S
Sl~1~l~\' or CHRO~lC H.U.AJlD L"\L>tX IS11MATt.S
FOR CUJUtL"'T SITE \1SlTORS
McCARL SUBSm:
CDr
CD! AdJUI&ed for IUD Huard
C'IIrmll:"8! (m2--'kP-ds") Absomtlon (mlP fO-dn) Oaotient
ClTRRE'-r Ht.~"TEF~
~U!'e Path,,",!,. In~s!i~~ or Se!!
Anuic 2.S 11er' No 1 ]I 10-3 OJm:12
Barium 1.3 IlC,..5 No 5 ]I 10-2 0JXm
Cadmium ".0 I 10"7 No 1 ]I 10'"3 0JXX)4
Qromhm: VI ~.5 I ]0.7 No 5 110"3 0.00J1
Copper 1.3 I ]C~ No ~ I 10"2 0.CXXX)3
MepDese 4.3 ][ 10~ No 2 110"1 0.CX002
S~lenium l..S x 10' i No 3 z 10"3 O.m>S
Zinc 8.7 I 10~ No 2 I 10"1 0,00))4
SubtOt&J (pathway) 0.002
E~u~~ Pa!n\lo"2\' D:rr.:!~ CalHa:'! 9.;:1': S~il
Arsenic: 3.0 I 10.9 y~s 9 I 10-4 OlXXm3
Cadmium ".9 ][ lC~ Yes 6 z 10.$ 0JXX)8
Chromi~ \1 6.6 ][ 1~ y~s 11 10-4 0.(XX)7
Copper 1.6 ][ Ie:": Yes 2 1 10"2 0.00XX)8
MaDpn~~ ~.2 X 10" Yes 6 I 10.3 0.00009
Selenium 1..8 1 10~ Yes 2 1 10.3 O.ooms
Zinc 1.11 lC~ Yes 11 10.1 O.COOXI9
SubtOLal (pathv.-a)') 0.002
Current Hunter Total Chronic Hazard IDd~ 0.003
Ct.TF.RE'-r HIKER (C'~LD)
Emosure Pa!nv.'8\": In£!estian t)f Sail
Arsenic: 6.5 1 10.7 No 11 10'"3 0.(0)6
Barium 3.3 1 10-4 No 5110"2 0.007
Cadmium 1.0110"' No 11 10"3 0.01
Chromium VI 1.4 I 10" No 5 1 10"3 0.003
Copper 3.4 ]I 10"$ No 4t S 10'"2 0.00J8
MaDpD~ L1 'C 10-4 No 2110"1 0.(0)6
Selenium 3.9 1 1006 No 3 I 10"3 0.001
%me 2.3 110-4 No 2 S 10"1 0.001
SubtotaJ(pathway) 0.03
..'U,-.nTI.JS4U
1
-------
TABl.£ 8
SLlof~1ARY or CHRO~'C HAZ.ARD n.'DE:X ESnMA11:.S
FOR CL"RR.£~"T sm \1SlTORS
McCARL SUBSm
(CoD11Dued)
Chtmlc:!'
COt
(me. r~-d8\')
CDI
AdJuss.ed for
AMO",tloD
IltD
lm./U-dlv)
E~t!"~ P2"~~"!\. D~~~' Cont!~ .;!t S~l~
AneDic
Cadmium
Qromi~ \1
Copper
Ma.ngaDc.se
Selenium
%in:
7.9 % lcr-9
U J 10'"7
1.7 1 10'7
4.1 J lC'':'
1.4 J lC<
4.7 X lC-8
:u x lO~
Yel
Yel
Yel
Yes
Yes
Yes
Yes
9 s lcrC
6 s 10"'
1 z lcrC
2 z 10"2
6 Z 10"3
2 z 10.3
1 z 10"1
SublotaJ (pathway)
CWTent Hiker (child) Tow Chronic Haurd IncSu
Ct~RE"""T It"\"E";LE ~~""'"T'Ep.
E~~uT'e P2'!-W2',-
1~~~C:f;,",,:,: C'~ So:!
JI.uard
Oaotftnt
o.cxml
0.003
0.002
. o.oo:m
O.o:m
0.0tm3
0.CXXXJ3
0.005
0.04
Aneni~ " 1 S 1(,-3 0.00J4
3.! s 1:'" No
Barium l.8 s IG~ No 5 z 10"2 0.004
Cadmium 5.6 J lC~ No 11 10"3 0.006
Chromiw= \1 i.t x lC<' No 5 z 10"3 0.001
Copper 1,~ s 10,$ 1'0 4 I 10.2 0.(0)4
Manganese 6.0 s 10,5 No 2 1 10"1 O.o:m
Selenium 2.1 J 10~ No 3 z 10.3 0.(0)7
Lnc 1.2 x lQ~ No 2 J 10"1 0.<006
Subtotal (pathway) 0.01
EXN)~ure Pa!),\1,'2'- D~rr.':a1 Con!a~t ",it}] SoH
Arsenic 4.2 J 10~ Yes 9 z 10-4 0.CXXXJ5
Cadmium 6.8 110"7 Yes 6 s 10-5 0.01
Chromium \'1 9.3 I 10.7 Yes 1 s 10-4 .0.009
Copper :u I 1006 Yes 2 s 10"2 Olml
MIDgIDe5C 7.3 x 10-6 Yes 6 s 10"3 0.001
Selenium 2..5 110"'7 Yes 2 z 10"3 Olml
. Zinc 1.5 z 10" Yes 1 z 10"1 Olm1
SubtotaJ (PathWlY) 0.Q2
CUrrent JuvcDile Hater TotaJ Qroaic Hazard IDdcx 0.Q3
,'U''''t\T''~2!
2
-------
Chrmlcal
TABLE 8
. Sl~1MAR\" or CHRO~lC HAZARD I!\1)EX ESTIMATES
FOR CtJRR£~'" SIn VISITORS
McCARL SUBS In
(CoDUDued)
CDI
1m, fk2-d!~.'
CDI
AdJusted lor
AMortltlot!
ClTRRE'i HTKEF, rE:DrBLES'
EftIo5urr Pa!hv."2'" In[!~stion of Soil
ArKDie
BariUII:
Cadmium
Chromium VI
Copper
MIDpDC.\e
S~Diwr.
Lee
2" J: leT' '7
1.2 J: 1 Q"'"
3.8 I 10<
5.2 J: 10~
1:2 J: 10.$
4.1 J 10.5
1.4 I 10<
5.4 J 10'~
No
No
No
No
No
t-;o
t-;o
t-;o
~~u~~ Pa!~\\'2'. D:rmal Co"t2~ ".;~~ S~i1
Anenic
Cacimiu::
Chromium \1
Copper
Manga%l~~
Seleniw:.
Zinc
4.9 J 10.9
7.8 J 1C~
1.1 J: 10'''1
2..S J: 10''7
8.4 I 1C"
2.9 I 1C~
1.7 I 10<
Yes
. Yes
YtS
YtS
YtS
Yes
"tS
IUD
1m2 tk..dn)
1 s 10"'
5 J: llr2
1 J: 10"3
5 S 10"
4 ]( 10.2
2 110.1
3 S 10.3
2 J; 10.1
Subtotal (pathway)
9 s lcrt
6 I 10.5
111~
2 I 10.2
6 I 10"
2 ]( 10.3
1 ]( 10.1
Subtotal (pathway)
Current Hiker (Edibles) Tow Chronic Hazard lDdex
Ct.TRRE~J HIKER (YEAR ROU~"D)
Emosur~ Palh""3'" In~~s!ion of Soil
Huard
Oaotirnt
O~
O~
0.004
0.001
0.00')3
0.00J2
O,OOJS .
0.00;)4
0.009
0.(00))5
0,001
0.001
O.(XXX)l
O.OOJl
O.OO:xn
O.OOX::
0.002
0.01
AneDic 1.8 J: 10"" No 1 s 10"' 0.(0)2
Barium 9.1 ]( 10"5 No 5 J; 10"2 Q.OO2
Cadmium 2..9 11006 No 1 s 10"' 0.003
Qromium VJ 3.9 I 1~ No 5 J; 10"' 0Jm8
Copper 9.3 11~ No 4 S 10"2 0.(0)2
MlDpDese 3.1 1 lCr5 No 2 1 10"1 0.0002
Selmium 1.1 s 1~ No 3 s 10"' 01m4
Zinc 6.3 I leT'S No 2 J; 10"1 0.Q003
Subtotal (pathwa~') 0.007
"'E"~ I\T8'-1$o12!
3
-------
TAB1..E 6
Sl"MM.~Y or CHRO~'C HAZ.AR.D INDEX E.S11MATE:S
FOR CL'RRE~'T sm VISITORS
McCARLSUBsm
(CoDtiDued)
Chrmlt:1!'
CDI
lmt! I~-de")
CDI
AdjulLed lor
AbsoM)tlon
am
Hazard
Ouotirnt
11n21k...dn)
~U~~ h!h\l.i!'- D~rm!.' Conta~ \1.it~ Soil
AneAic l.2 11er' Yea 9 1 10-4 O.cxxm
Cadmium 3.5 110"7 Yea 6 1 10"' 0.006
Cbromi~ \'1 ".8 z 10"7 YeJ 11 10-4 O.ooS
Copper 1.11 1~ Y~ 2 I 10-2 0.CXXX>6
M~ 3.8 1 10~ Y~ 6 I 10-3 0.(0)6
Selenium 1.3 z 10.7 Yc.s 2 I 10-3 O.(XXX)S
Lnc 7.7 J 10~ Yc.s 1110-1 OJ:tm7
Subtotal (pathway) 0.01
Cun'CDt Hiker (Year Round) Total CbroDic Hazard lDdcx om .,
ClTRRE'" FARVEF
E:r:!'~su.~ P2~h\\'2\. Jr.~~(~;C\~ Ctf s~:!
Arseni: 1.1 z 10~ No 11 10.3 0.001
Barh:m 5.5 x 10~ J'.;o 5 I 10"2 0.01
udmiL:.::: 1.7 x 10,$ J'.;o 11 10"3 0.02
ChromiWI: \'1 2.4 x 10,$ No 5 I 10.3 0.005
Copper 5.6 x 10.$ No ~ 1 10.2 0.001
Maag.a.oc.s.e 1.9 z 10~ No 2 I 10.1 O.cm9
Seleniu: 6.4 x lo~ t-;o 3 I 10.3 0.002
Zinc 3.8 x 10" No 2 I 10.1 0.002
Subtotal (pathway) 0.04
Exnosure Patn\1.'3'- Dermal Contae'l \1.itn Soil
Arsenic 2.2 11er' y~ 9 I 10-4 omm
Cadmium 3.5 110.' Yes 6 1 10.' 0.006
Chromium VI ~.8 110"' Y~ 11 10-4 0.005
Copper Lll 10-6 Yes 2 110-2 OJXm6
MlDpDese 3.8 1 10-6 Yes 6 1 10-3 0.0006
SdCDium UIIO"' Yes 2 110-' O.oo:x>S
Lnc 7.7 1 10-6 Yes 11 U)"1 O.oo:x>7
Subtotal (PathWlY) 0.01
Current Farmer Tow Chronic Hazard lDdcx 0.05
.IE" w-s n T aa..lSo&2!
..
-------
TABU: 9
SUMMARY or Sl"BCHRO~'C A.'"D CHROSIC HA.ZAJW ~"Dt.X EST1MAT£S
FOP. n. 'TU"R£ ONSITt IlLSIDt.l\&S
IAIt.P. SUBSm:
SDI/CDI .
SDI/CDI Adjualed for IUD Hu:ard
p~ml~1 (mE! IkR-da \., Absof"l)tloD (nu~ fUo4!n) puotitllt
Ft. 'rft TR E C'HTl.. t> R E5!D E''''
~~urt Pa!~"-"'a\. In~.'ior. d Soj~
AneDic 8.1 s 10-' No 1.0 I 10-' O~
Cadmium 2.0 s lcr3 No 1.0 s leT' ~
Chromium \1 7.9 J 10"3 No 2.0 I 10-2 0.40
Sclcnium 2.6 x 10~ No 3.0 s leT' 0.09
%iDe 1.S x 10.1 No 2.0 11()"1 0.91
SubtOtal (pa1hway) 3.51
Eft\~ur~ Path\l.'2'- D~rm21 Con!aC'! v..;t}: Soil
Arsenic 7$ x 10's YC5 9.0 11er' D.09
Cadmium 2.0 x 1cr' Yes 6.0 I 10.5 . 3.27
Chromium \1 7.6 x 10~ Yes 4.0 I ler' 7.65
Selcnium 2.S x 1cr' Yes 2.4 I leT' 0.10
~c 6.8 J 10.2 Yes 1.2 s leT1 0.73
Subtot&! (pathway) 11.84
future Child RwdeD: Tot&! Subchronic Hazard IDda 15.4
F'LTTt. "RE ADt ~ T REC:!DE'i
Ernosur~ Pathv.'2'- In~~.~ior. of SoH
ArKnic 9.2 J 10~ No 1.0 x 10'" 0.01
Cadmium 2.3 x 1~ No 1.0 x 10"3 0.23
Chromium VI 9.1 s 10~ No 5.0 s 10"3 0.18
Selenium 3.8 x 10.5 No 3.0 I 10"3 0.01
2mc 2.11 10.2 No 2.0 I leT1 0.10
Subtotal (patbway) 0.53
Emosure Parh\l.'2\": Derma1 Conrad ",;th Soil
Arsenic 2.S I leT' Ya 9.0 1 lcr4 0.03
Cadmium 6.3 I 10'" Yc.s 6.0 110-' LOS
Chromium VI 2.4 I lcrt Yc.s 1.0 11~ 2.45
Selenium 8.0 I 10" Yc.s 2.4 I leT' 0.D3
Zinc 2.B I 10.2 Yes 1.2 1 leT1 0.24
Subtotal (patbway) 3.80
.R,,~"T'2A425
1
-------
TABU: 9
St~fM.I.RY or SUBCHRO~1C A."tD CHRO~1C HAZARD L"-"DEX ESTIMATt:.S
. FOR FL-nJRL ONsm JtI:.SIDEP\"TS
BAIER SUBSrn:
(CoatiDDed)
Chrm'~'
. SDI/CDI
(mr r~.al'\.)
SDI/CDI
AdJusted lor
AMOnJtlOD
am
(mil: /bod! \)
Huard
Oootirnt
EXMstJre Pa'h.'2'- Ir.,,~c~i"'. or Hom~~C'v.T. V~~tl!bl~s
Cadmium
SckAium
1.9 J; lcr2
U J; 10.3
No
No
1.0 It 10'"
3.0 It 10'"
SubtotaJ (path-ay)
19.0
0.58
19.58
future Adult Resident Total Chronic Haurd IDdu
%3.9
"'U\~I\T.ZA£Z!
2
-------
TABU 10
SL~1.'1ARY or Sl"BCHRO~lC A.'"D CHROSJC H.o\Z..IJlD I}\"DEX ESTIMATES
FOR n"1"L'lU: ossm IlESJD£t\7S
McCAJU. Sl7BSrn:
SDJ/CDJ
SDI/CDI AdJusted for IttD Hazard
C'htm ic:1l I (mlllk1>-de') AbsorDtlon (mlllb-dn) QuotieDt
FL 'Tl!RE C1.r.LD RE!!D E''',T
~U~t Pa!h~-a'. In~~s!io~ or Soi!
Anc.Dic 5.6 x 10'" No 1.0 z 10"' 0.06
Barium 2,4 1 10"2 No ,.0 Z 10"2 0.49
Cadmium 5." z 10-- No 1.0 z 10"' 0.54
Chromium VI 9.9 I 1~ No :LO z 10"2 0.05
Copper 1.7 I 10"3 No 4.0 :I 10"2 0.04
M&DiaDe.\C 1.0 I 10.2 No 1.0 z 10"1 0.11
Selenium 1.7 J 10" No 3.0 z 10'" 0.06
LDc 1.7 z 10.2 No :La z 10"1 0.09
SubtOtal (pathway) 1.44
E~scre P2!h""'2'- D:rrr.2~ Contact v..;tt-~
Arsenic 5.4 I 10.5 Yes 9.0 :I 104 0.06
Cadmium 5.2 I 10.5 Yes 6.0 z 10.5 0.86
Chromium \1 9.6 I 10.5 ''1' es 4.0 J 104 0.96
(;()pper 1.6 I lC" Yes :La x 10.2 0.08
MaDgaDe.\C 1.0 x 10.3 Yes 3.0 z 10.3 0.34
Sdenium 1.7 I 10-- Yes 2.4 J 10.3 0.07
Zinc 8.3 x 10.3 Yes U z 10.1 0.07
Subtotal (pathv.'3) 244
Future Cbild R.esidcDt Total SubchroDic Huard lDdex 3.9
F't'TlTRE ADt'l.T RESIDE'"
~sure Pathw2'- In~estion Qf Soil
AneDic 6.3 z 1~ No 1.0 z 10.3 0.01
Barium 2.8 z 10.3 No ,.0 Z 10-2 0.06
Cadmium 6.1 J 10.' No 1.0 J 10"' 0.06
Chromium VI 1.1 J 104 No 5.0 J 1()"3 0.02
(;()ppcr :La z 104 No 4.0 z 10"2 0.00
MlDpDese U J 10"3 No 1.0 Z 10-1 0.01
Selenium 2.0 z 10.' No 3.0 z 10"3 0.01
LDc 2.0 z 10"3 No 2.0 z 10"1 0.01
Subtotal (pathway) 0.18
.n"~1\T'U$oUS
1
-------
TABU: 10
SLTM~1.;JtY or St"ECHRO~'C A.~D CHRO~'C HAZ.ARD J]\"DE:X ESTlMATE:.S
. FOR F"L"'I1.1\E ossm RESID£~"TS
Cbtmlo.l
McCARL SUBSnt:
(CoDtiDued)
SDt/CDI
lmll'k1!.dl!\)
SDI/CDI
Adjusted ror
AbSOrDtloll
~u,~ Pa~h,..,~\. D~~~ CClfH2:t .itb ScD
ArseDie
Cacimiu.m
Qromium \1
Copper
MupDese
Selenium
%iDe
~ocur~ Pa:hv,'2\-
Cadmium
S~lenium
"U\~1\T8U$42S
1.7 z 10.5
1.7 z lcrs
3.1 Z 10.5
5.3 1 1~
3.3 1 1(1~
5.4 X 10.5
2.7 X 10.3
Yes
Yes
Yes
Yes
Yes
Yes
Yes
Ir.~~('j,,:" C" HI"\:!1~~~"""!"- \'~~~!a~l~s
5.0 X 10.3
1.2 X 10':!
No
No
IUD
(mlllb-dn)
9.0 s 1~
6.0 s 10-'
1.D s 1~
2.0 I 10"2
3.0 11 10"3
2.4 S 10.3
1.2 S 10"1
Subtotal (pathwa)')
1.0 I 10"3
3.0 11 10"3
Subtotal (pathwa)')
Future Adult Resid:nt Total Chronic Hazard lDdex
"
..
Huard
QDOCicDt
0.Q2
Q.28
0.31
0.Q3
0.11
om
om
0.79
5.02
0.39
5,41
6.4
-------
"AhU~ II
SUMMARY Of'CANC~R RISK r.mMA1T~
. hA R:R StJ~rIT
~~~i~l
. CDI
(mr./kr. -
!tan
W~ir.ht
of
r "j,lf'nc~
SF
5on'~.
Chemicaf-
~l"'Cir;c
BJ~k..
SF
(mr./ltr.-
~:'Itl
Ql!tR [NT SJ..IUJSITOR - HUNTER
Tot.t
1'It." .".,
~i,\
TottI
r _p"nre
Ri,k.
[1tp-05Ure Pathwa\*: 'nRestion or 52iL
Arsenic
1.6 J( 10"
A
IRIS
.J It ro"
8.7S
EItDosure Pathway: Dermal Contact with Soil
Ars~nic
1.9 J( 10"
.. It to'
1.94
A
SF ....I GI
ah~orrlion
.3 It rn-ll
.. It 10'
CURRENT SITE VISITOR - HIKER (CHILD)
Tot:" Ifunter Cancer R i~1t
EJlDosure Pathway: 'nRestwn or Soit
Arsenic
1.6 J( 10"
3 J( 10.r
1.75
A
IRIS
EKDosure Path WIlY: Dermal Contact with Soil
Arsenic
2.0 J( 10"
.. J( 10"
8.94
A
SF GrIll GI
ahsorption
3 J( 10"
.. J( 10"
Total Hiker (Child) Cancer Ri~1t
WMt\T1I,\I<;4"
I
3 It 10-"
.J It 10.r
-------
T A nl.1~ II
SUMMARYOFCANcrR RISk rAmMA1T;..~
Qi-'~J!'jc:.t
rol
(mr.'kr.-
~:ttl
SF
(mr.'k~-
~bJ.l
CURRENT SITE VISITOR - JUVENILJ.Jll!~Tr,-~
[IIDosure r:tthwav: Inltestion of Soil
A~t.nic
2.2 x 10-'
1.7S
[IIDOsure rathwav: Derm;d Contact .it~
Ant.nic
2.7 J( 10-8
1.94
CURRENT SITE VIStl''OR - HIKER fEOlDtrS}
EIlDO$Ure Pathway: 'nRestion or Soli
Arsenic
1.5 I 10.'
1.7S
[IIDOsure Path"lV: Dermal Conflct wilh Soil
Arsenic
:1.1 J( 10"
1.94
.IF f\wp.\1\",~'"
nA .r.R SUrn\11"E
(Conlinur.ct)
W~ir.ht
of
r..~i""nc~
SF
~"'c~:
Chemiettl-
SfM'Cific
~i"k.
Tobll
r:.lhW1llY
Jt.i'l~
Tnbl
F.JI('Mnn!
Ri<:~
A
IRI~
A
SF ",,,,/ GI
a"',;orplio"
.. II 10.'
S II 10 II
.. II 10.'
S II 10.fl
Tolal Juvenile Hunter Cllncer Ri!lt
A
IRIS
A
SF.,..,I GI
8bo;orplion
J II 10-'
6 J( 10"
J J( 10.'
6 J( 10"
. T~tal Hiker (£.dible!) Cancer Ri~k
2
;.
41110.'
) II 10.'
-------
.
,. A hU~ II
SUMMAR V OF CANCER RISK ESt1MATF..~
DAIER St~rTE
(Con.inuf"ft)
Qt~mial
CDI
(mK/IcI-
11m
W,.ir.ht
of
.r"id~n~
SF
Source.
SF
(mr./ltr.-
~:lrl
CURR£NT SITE VISITOR - HIKER (Y£AR RQill'O)
Chemnl-
S~ific
~i~~
Total
h.hW1ty
,i,\
Tobl
E J(lM"nN'!
~;,\
Exposure rafhwlY: 'nles'io" or Soil
Anenic:
1.1 II 10"
A
IRIS
1.1S
[xl)()sure Pathway: Dermal Contact with Soil
Anenic
1.4 II 10"
A
SF ~..I GI
ab~ot,,'ion
1.94
CURR£NT SITE V.SlTOR - FARMER
Exoosure Pathway: '"Res_ion or Soil
Anenic
6.8 JI 10.'
A
IRIS
1.7'
EXl)()sure Pathway: Dermal Contact with Soil
Arsenic
I." II 10"
SF.../ GI
ab!orption
1.94
A
~WP.U\ TMIS4"
J
2 x 10.'
J x 10 ~
2 J{ 10.'
J II lO~
Tot=-Ilfiker (Velr Round) C.ncer Ri,1c
I II 10"
3 II 10"
I II 10"
) II 10"
Tot:" Firmer Cancer Ride
2 x 10.'
I II 10 ~
-------
..
I
~E II
SUMMARY OF CANcrR RISK FStlMA1T-S
OA IF.R Stnr:;rrn
(ContinuNf)
Q!.C1.~i~t
CDt
(m~/ltl-
dul
SF
(mr./ltr.-
~:trl
W~ir.ht
of
r.yiff~~c~
r!lIURE ONSrTE CHILD RESIDENT
[JlDosure Pathway: InRestion of Soil
Arsenic
6.9 1 10"
A
1.75
EJlDosure Pathway: Dermal Contact with S4ill.
Arsenic
8.9 " 10"
A
1.94
FUTURE ONSrTE "DUL T RESIDENT
EXDOSure PathWlV: 'nRestion or Soil
Arsenic
~.O JI 10"
A
1.75
EIDOSuie PathWlV: Derml' Contact with Soil
Arsenic
I.i JI 10"
A
'.94
S 4\WP.I'\TMI54:15
SF
Sou!..~-
Cheminl-
SfW'Cific
~ i~lt-
IRI~
1 )I 10"
SF «If" I Gt
ah!;orption
2 " to"
Tota' Onsite Child Resident Cancer Risk
IRIS
11 10"
SF mil GI
.bsorption
2 JI 10"
Tohll
I"IIthway
~i,~
I )I 10"
2 " 10"
7 1 10"
2 JI 10"
Total Onsite Adult C.ncer Risk
4
Tobl
r.-fN"Uf'f'
~i,,~
) II 10"
1)1 10'"
-------
TAnu~ 12
SUMMARY OF CANCER RISK FSt1MATES
~~1
cot
(mr./ltr.-
~lli
SF
(mr./ltr.-
~:'I.tl
~UR R EJIT..SITE VISITOR - HUNTER
~Q$ure r~",.y: InRestion or SoiL
Anenic
1.0 J( 10"
1.7S
E){oosure PathWlY: DermaLContacl with Soil
Anenic
1.2 Jt 10"
1.94
CURRENT SITE VISITOR - HIKER fCIULO)
~J(DOsure Pathway: InRestion or Soil
Arsenic
1.0110"
1.7S
~JtDOsure Pathway: Dermal Conl8Cl with SoiL
Anenic
1.3 1 10"
1.94
.J't\WM1\T1IU547!
McCARl. !;U1l-;rrn
Weir.ht
or
r,-.jd~~c~
!;F
~"~e-
A
IRI~
A
SF fJlrA 1 GI
"h~orption
A
IRIS
A
SF _I GI
absorption
Chemic8l-
~iric
BJ,1t
To..1
p,.thwaJ
Jtj,\
2 J( 10 II
2 J( lO~
2 J( 10.
2 J( 10.
Tot:" Hunter C.ncer Rbk
2 J( 10"
2 J( 10.'
2 J( 10"
2 Jt 10"
Total Niker (Child) Cancer Ri~k
Tobll
r.-I'M0""
Ri,\
2 II lO-fl
2 II 10.1
-------
.
TAhLEI2
SUMMARY OF CANCER RISK rsnMATF:S
McCARl. StJRSfTF.
(Continued)
~~~!~!
COt
(mr./kr.-
~:t..Il
!-;F
:;n"rre.
Weir.ht
or
r. v if',""~~
!-;F
(mr./ltr.-
~hYl
CUR R [NT SITE VISITOR - JUVENltr I1!ltJJ:rJ.t
Chemal-
!-;fW'Cir.c
Ri..~
Tob1
hthwwy
pi,,\
Tohl'
F. . fM"'I"'
Ri..\.
fu»osure Pathway: InRtstion of Soil
Anenic
1.4 J( 10"
A
IRIS
1.75
Elloosure Pathway: Dermal Contact wilh Soil
Anenic
1.7 J( 10"
A
!-;F ",.,1 GI
ab~orplion
1.94
CURRENT SITE VISITOR - HIKER (EDIOLES)
Elloosure Palhway: Inlntio" of Soil
Arsenic
9.6 J( 10"
A
IRIS
1.7S
~lIoo,ure Pathw..: ~t Conlact wilh Soil
Arsenic
2.0 J( 10"
A
SF Grlfl GI
ab,orption
1.94
Jrflwr5f\f194J!W15
2
2 II 10"
J II 10"
'- II 10"
111 10"
Total Jlivenilf! Hunter CRncer Ri~k
2 II 10"
4 J( 10"
2 II 10"
.. I( 10.
Total Hileer (Edibles) C8n~r Ri,k
2 I. 10 '
2 II 10.'
-------
TAIIU~ 12
SUMMARY OF CANCER RISK F..S11MATF.s
McCAR L StJIISITE
(Continued)
Chemical
CDt
(mR/kR-
ila.D.
Chemal-
Specific
B.i'lk.
SF
(mp,/kR-
!farl
Weir,ht
of
f!y_iflen~
SF
Zonr~ .
CURR£NT SITE VISITOR - IIIKER (YEAR ROJ,lli.O)
To"l
~th.".,
'U,,,
Tobl
r: -I'M""'
~ i~"-
t~ure Pathway: .nRestion or Soil
Arsenic
7.2 It 10"
I x 10.'
1.7S
A
IRIS
[xoosure hthway: Dermal Con tiel with Soil
Anenic
1.7 It 10"
I x 10 ~
1.94
A
SF ...../ GI
amorption
I J( 10.'
2 x 10.'
Total lliker (Yelr Round) Clncer Ridt
CURRENT SITE VISITOR - FARMER
EJloosure Pathwa¥: In..alion of Soil
Arsenic
4.3 ]I 10"
1 JI 10"
1.75
A
IRIS
Eltoosure Palhwa¥: Dermal Contact with Soil
Arsenic
1.7 It 10"
2 It 10"
1.94
A
SF onIl GI
Ib!Orplion
1 It 10.'
2 I 10"
TOIIII FIrmer Clncer Ri!k
.If 4\wr5"t1M.r."~
:I
I It 10.' .
1 It 10.'
-------
TAbLE 12
SUMMARY OF CANCER RISK r:..cmMA1T:S
~~!
CDI
(mw/kK-
itm
SF
(mft/8cK-
~:lY1
FUTURE ONSfTE CHILD RESIDENT
EJloosure Pathway: InRestio" or Soil
Anenic
4.8 I( 10"
1.7S
EXDO$Ure Pathway: Dermal Contlct with Soil
Anenic
6.1 I( 10"
1.94
FUTURE ONSITE ADULT RESIDENT
EXDOsure Pathway: InRestio" or Soil
Anenic
2.1 It 10.
1.1S
EXDOsure Pathway: Dermal Cantle' with Soil
Arsenic
1.~ It 10"
1.94
JF~WP!t\T1MJ5."
McCARL sunSITE
(Continued)
Weiftht
or
~vi"~n.~
SF .
~-~!ct:.
A
IRIS
A
SF Clr881 GI
absorption
~mical-
S~iric
~j~~
It x 10"
1 x 10"
Tobl
r:.th..,
~J,~
It x 10"
1 X 10"
Total Onsite Child Resident Clncer Risk
,
A
IRIS
A
SFCIr88/GI
.bsorption
S I( 10"
1 .. 10.5
S I( 10"
II( 10"
. Totlll Onsite Adult Clncer Rhk
4
;.
Tobll
1:.,"",,",
Ri,~ .
2 x 10"
2 x 10"
-------
TABLE U
SUM.\-tAR\' or BLOOD 1LAD 1E\'ELS
fl-ThU JU:SID~" CHILDREN
f5~ va.
SoU CoDcau.tiou
(m2!k.R)
Meall
Blood Lad UwI
(u2/dU
Baier Subsit e
em
3192
39.3
McCarl Subs.Ue
7.i1
Blood Iud levels were cicrivc.d nrili';"f the foUcrwiDg equation.:
Pb blood . C IDiI S 51 s AF x BKSF + Pb b8ctp'DUftd
Where: CiOU . lOillcad CODCCDU'aUOD
51 . IOU ingestion rate (0.010 a/day)
AF . lutrOUltestina1 absorption factor (0.20)
BKSF . biokiDetic: .tope (actor (0.20)
Pb~~ . background blood Iud lcvc1 (5 ug/dL)
EWmatcs of blood Iud levels using the EPA's ClUTCDtJy available Upt.ake/BiokiDcUc (UBK) model
(Version 4.0) indicated that greater blood lead levels at the McCarl lubsite (a lDeaD o( 8.8 ug/dL) ..owd result
among future resideDt children. Blood lead levels It the Baier IYbsite could Dot be estimated because the
EPA', UBK (Version 4.0) model is appropriate for estimating blood Iud levels in chlldr= only when sou lead
conccntratiolLS are less thaD 2(XX) mg/kg.
.
I&I\U.C::S\D216\na1~7
------- |