United States Office of
Environmental Protection Emergency and
Agency Remedial Response
EPA/ROD/R07-91/050
June 1991
Superfund
Record of Decision:
Lehigh Portland Cement, IA
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50272-101
REPORT DOCUMENTATION 11. REPORTNO.
PAGE EPA/ROD/R07-91/050
I ~
3. Redplenta Acce88lon No.
4. T11Ie and Subtitle
SUPERFUND RECORD OF DECISION
Lehigh Portland Cement, IA
First Remedial Action - Final
7. Author(.)
5. Report Dete
06/28/91
6.
8. P8rf0nnlng Organization Rept. No.
II. Perfonnlng Org8lnlz81lon Name and Add....
10. Projec:1/T-*iWork Unit No.
11. Contnoc1(C) or Gr.nt(G) No.
(C)
(G)
1~ ~orIng Orgenlz8tlon Name and Addre..
U.S. Environmental Protection
401 M Street, S.W.
Washington, D.C. 20460
13. Type of Report . PerIod Covered
Agency
800/000
14.
15. Supplement8ry Note.
16. Abetr.ct (Umlt::!OII word.)
The Lehigh Portland Cement site is composed of two areas: the 150-acre Lehigh
Portland Cement Company (LPCC) cement production facility, and the 410-acre Lime
Creek Nature Center (LCNC), in Mason, Gordo County, Iowa. Land use in the area is
rural, agricultural, and industrial. The site overlies an aquifer that serves as a
source of water for 12 nearby wells; and municipal water is obtained from a deeper
aquifer. Calmus Creek borders the site and discharges to the Winnebago River,
located within a mile of the site. From 1911 to the present, the LPCC has
manufactured cement products. As a result of operations, site features currently
include four abandoned quarries at the LPCC area, which were worked until the 1950's
and subsequently were filled in with water, and numerous tailings piles. The water
bodies are known as Blue Waters Pond, Arch Pond, Cooling Waters Pond, and Area C
Pond. During its history, the LPCC disposed of cement kiln dust (CKD) in several
onsite piles and in Area C Pond. The LCNC area was used by LPCC to quarry materials
until 1979, and subsequently was backfilled with CKD from the parent site and sold.
Consequently, the LCNC quarries also have become ponds, including Quarry Pond. In
1981, hydrochemical tests of Blue Waters Pond on the LPCC area indicated high
(See Attached Page)
17. Document An8Iy8I. L Deecrlptore
Record of Decision - Lehigh Portland Cement, IA
First Remedial Action - Final
Contaminated Media: gw, sw
Key Contaminants: metals (arsenic, chromium, lead)
b. IdentifienllOpen-Ended TetT118
c. COSATI ReIdIGroup
18. Avail.bilty St8tement
111. SecurIty CI... (Thl. Report)
None
20. SecurIty CI... (Thl. Page)
None
21. No. of P.ge.
52
I
n Price
(See ANSl-Z39.18)
See tMrrucliOM on ~ve,..
272 (4-77)
(Formerty NTIS-35)
Depertment of Commerce
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EPA/ROD/R07-91/050
Lehigh Portland Cement, IA
First Remedial Action - Final
Abstract (Continued)
alkalinity. Subsequent investigations indicated that the ponds on the LCNC area also
have high pH levels, although water quality is better than at the LPCC area. Testing
showed that CKD was the cause of high alkalinity, and that contamination of t~e aquifers
has occurred. In addition, a flow control structure installed on the southeastern corner
of Blue Waters Pond allowed highly alkaline water to discharge into Calmus Creek.
Subsequently, overflow prevention measures at Blue Waters Pond were implemented by LPCC,
but seepage to Calmus Creek continued. This Record of Decision (ROD) addresses the CKD,
ground water, and surface water as a final remedy. Elevated pH of ground water and
surface water also is of potential concern.
The selected remedial action for the LPCC area includes dewatering Blue Waters, Area C,
and Arch Ponds, and treating pond water using acid neutralization, followed by ion
exchange or reverse osmosis if needed, with onsite discharge; excavating and
consolidating CKD from Blue Waters and Arch Ponds within Area C Pond, followed by
constructing a clay cap over Area C Pond; constructing a cap over the existing area known
as the CKD Reclamation Area; collecting shallow ground water via sumps and a seep
collection system constructed in the base of Blue Waters and Area C Ponds, and treating
the ground water in the onsite treatment system before onsite discharge; monitoring
ground water, surface water, and treated discharge; and providing institutional controls
including deed restrictions. The selected remedial action for the LCNC area includes
constructing a dam across Quarry Pond and draining the western portion of the pond;
excavating CKD within the western portion of Quarry Pond and consolidating the CKD within
an exhausted quarry east of the pond; constructing a clay cap over the exhausted quarry;
consolidating CKD from all other LCNC areas in the Badlands area, and constructing a clay
cap over the consolidated material; allowing Quarry Pond to refill; and monitoring ground
water and surface water. The estimated present worth cost for remedial action at the
LPCC area is $3,400,000, and for the LCNC area is $1,600,000. No O&M costs were provided
for the remedial action.
PERFORMANCE STANDARDS OR GOALS: Chemical-specific ground water clean-up goals for both
the LPCC and LCNC areas are based on the more stringent of SDWA MCLs and State standards,
and include arsenic 0.00003 mg/l (State), lead 0.015 mg/l (State), chromium 0.5 mg/l
(MCL), and pH 6.5 to 8.5 (Secondary MCL).
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UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION VII
726 MINNESOTA AVENUE
KANSAS CITY, KANSAS 66101
MEMORANDUM
SUBJECT:
Record of Decision for the Lehigh Portland Cement Company
Superfund Site, Mason city, Iowa'
FROM:
David A. Wagoner
Director, Waste Management Division
TO:
Morris Kay
Regional Administrator
This Record of Decision presents the proposed remedy for the
hydraulic containment and treatment of ground water and capping of
cement kiln dust at the Lehigh site in Mason city, Iowa.
The major components of this remedy include dewatering of the
quarries, consolidating the cement kiln dust, capping of the cement
kiln dust, institutional controls, and continued monitoring to
ensure the efficiency of the remedy.
This Record of Decision has been prepared by the Iowa
Department of Natural Resources and coordinated with the Office of
Regional Counsel, the Office of Public Affairs, the Congressional
and Intergovernmental Liaison, and the Agency for Toxic Substances
and Disease Registry.
On March 8, 1991, the remedy selection authority for the
Lehigh site was delegated to you by Don R. Clay, Assistant
Administrator. I recommend approval of the proposed remedy.
Attac~ '
~~- 6'Z~-'/
Approva -
Disap~)roval
/
/
(
RECYCLE ~.~
..... :QII~.1if$ lit: .:.1: '8181
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RECORD OF DECISION
FOR
LEHIGH PORTLAND CEMENT COMPANY SITE
MASON CITY, IOWA
PREPARED BY:
IOWA DEPARTMENT OF NATURAL RESOURCES
June 25, 1991
.
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RECORD OF DECISION
LEHIGH PORTLAND CEMENT COMPANY
MASON CITY, IOWA
DedantiOD
1.0
Site Name and Location
Lehigh Portland Cement Company, Mason City, Iowa
1.1
Statement of Basis and Purpose
This decision document prcscnts the selcc:ted remedial action for the Lehigh Portland Cement Company
Superfund site located in Mason City, Iowa. The remedial action was chosen in accordance with
CERCLA, as amended by SARA, and, to the extent practicable, the National Contingency Plan. This
decision document explains the factual and legal basis for selecting the remedy for this site.
The Iowa Department of Natural Resources concurs with the selcc:ted remedy. The information
supporting this remedial action decision is contained in the administrative record for this site.
1.2
Assessment of the Site
Actual or threatened releases of hazardous substances from this site, if not addressed by implementing
the response action selcc:ted in this Record of Decision, may present an imminent and substantial
endangerment to public health, welfare or the environment. The essence of risk resulting from this site
is environmental and the public health risk is not as great.
13
Description of the Remedv
The selcc:ted remedy consists of the foDowing actions:
.
Draining of Lehigh site ponds which contain high pH water, acid-neutralization, and discharge
to Calmus Creek or the W'mncbago River. Drainage of the site ponds wiD create a sump which
should also coUcc:t shallow high pH groundwater in the site area.
.
Coastruction of a drain system to coDcc:t runoff and groundwater inflow to the site ponds.
.
Consolidation of cement kiln dust (CKD) deposits in Area C and other site ponds.
.
Placement of aD engjneered clay cap over the consolidated dust as weD as the cement kiln dust
in the 8CKD Reclamation Area8 to minimize infiltration of water through the kiln dust.
.
Installation of kiln dust dewat~ring weDs, if nccessuy to facilitate kiln dust dewatering in the
CKD Reclamation Area.
.
Treatment of contaminated waters to meet Iowa NPDES discharge permit limits with discharge
to Calmus Creek or the W'mnebago River (Wmnebago most likely).
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.
Assurances that the drainage system will be operated in perpetuity to maintain isolation of
water &om the waste kiln dust and collect and treat any contaminated water which is generated.
The selected response action constitutes final action for this site. The selected response action addresses
the principal threats of cement kiln dust which acts as a source of contamination to the surface water
and groundwater. The existing contaminated groundwater will be removed and treated thus preventing
off-site migration. The waste kiln dust will be isolated &om water to the extent practic:al to minimize
production of contaminated water. A:D.y contaminated water which is produced will be collected, treated,
and discharged.
1.4
Declaration of Statutorv Determination
The 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 remedial action, and
is cost-effective. This remedy utilizes permanent solutions an4 alternative treatment (or resource
recovery) technologies to the maximum extent practicable and satisfies the statutory preference for
remedies that employ treatment that reduces toxicity, mobility or volume as a principal element.
Because this remedy will result in the source of hazardous substances (kiln dust) remaining on-site, a
review will be conducted to ensure the remedy continues to provide adequate protection of human
health and the environment within 5 years after commencement of the remedial action.
~~~STRATOR 6 - 2 ~~q I
ENVIRONMENTAL PROTEcrION AGENCY, REGION VD
aN:URRED rn
~-::> ---c;--~ \ ,,~ ~. /~
ALLAN STOKES, ADMINISTRATOR
IOWA DNR, ENVIRONMENTAL PROTEcrION DMSION
~/0?6j ~I
I ATE
3
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Decision Summary
2.0
Site Name. Location. and Description
The Lehigh Portland Cement Company property is located at 700 25th Street on the north side of
Mason City in Cerro Gordo County, Iowa (Refer to FJgUre 1). The site is situated in the northern half
of Section 32, Township rn North, Range 20 West and the eastern half of the northern half of Section
32, Township rn North, Range 20 West. The area of investigation is bordered by 25th Street on the
south, State Highway 65 on the cast and northeast, the Chicago Rock Island and Pacific Railroad and
Calmus Creek on the West. Rural and agricultural areas lie to the cast and west of the site with
Northwestern States Portland Cement Company to the south and American Crystal Sugar Company to
the north. The Lime Creek Nature Center is approximately one mile northeast of the site. CaImus
Creek flows to the W'mnebago River which is less than a mile east of the site. The W'mnebago River
flows north of the Lehigh site, as well. The W'mnebago River aDd Calmus Creek are used mainly for
recreational purposes.
2.1
Site Historv and Enforcement Activities
The LPCC facility has manufactured cement since 1911 and is currently manufacturing a hydraulic
cement. The Lehigh site covers approximately 150 ac:res and consists of a cement manufacturing plant
and associated buildings and four abandoned limestone quarries and tailing piles (FJgUre 2). The
abandoned quarries on the Lehigh property are: Blue Waters Pond, Arch Pond, and Area 8CO Pond.
Another pond, mOWD as Cooling Waters Pond, is located west of the plant. This pond provides cooling
wa~r to the plant's rotary kiln and accepts warm water returned hom the plant. The abandoned
quarrie~ are filled with water. Unreclaimed waste kiln dust has been disposed of in the northern quarry
(Area 8CO Pond). Several piles of waste cement kiln dust (CKD) surround the perimeter of this pond
as well as protrude hom the water. CKD is piled in other locations as weD, and can be seen mixed with
soil on the site. Some of the CKD piles have been graded and revegetated.
"
The process of manufacturing cement generates large quantities of waste kiln dust. Kiln dust is the
waste produced from the process of heating the raw materia1s. During the manufacturing of portland
cement raw materials such as limestone and clay are quarried then aushed, dried, and mixed in the
correct proportions. This mixture is ground to a fme powder then burned in a sloping rotary kiln
maintained at a temperature of about 2600-2800 F. to form a glassy 8clinker8. The 8clinker8 is aushed,
a smaD amount of gypsum is added, and the mixture is reground to form cement.
Collection of the dust is difficult because it is entrained in large volumes of hot exhaust gases and it
often contains unacceptable high concentrations of alkalies (sodium and potassium) which make it
unsuitable for return to the cement-making process. At Lehigh, the unreclaimed CKD was placed in
piles throughout the facility and a large quantity has been disposed of into the northern quarry (Area
8CO Pond). Waste CKD is now landfilled in the clay quarry area.
The chemical composition of kiln dust is determined by the composition of the raw materia1s and the
conditions the dust particles have encountered in the kiln. The major constituents of this hydraulic
cement are calcium oxide (lime), aluminum, silica, and iron oxide. Magnesium oxide, sodium,
potassium, and sulfates are also present. Trace quantities of chromium, lead, zinc:, and other metals may
be present depending on the source of raw materia1s used to manufacture the cement. Waste kiln dust
contains fine particles of cement composed of these constituents and fossil fuel combustion products.
Waste kiln dust has highly corrosive properties and produces large quantities of hydroxides when
combined with water. At the Lehigh site, the CKD has a pH value as high as 13.0 units. Corrosivity
is characterized by a pH that is equal or greater than 12.5 units. Cement kiln dust has been designated
a special study waste under the Resource Conservation and Recovery Act (RCRA). Human or animal
contact with such highJy corrosive material causes chemical-type burns of exposed tissue. High pH levels
4
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in water also limit the survivability of aquatic organisms, including fish.
It has been estimated that a minimum of 136, tons of waste kiln dust has been disposed of on site
since 1981. No records are available for the 70 years before 1981. Consequently, the actual amount of
waste disposed of on site is probably much greater than 136, tons and has been estimated at over
1 million tODS.
The Mason City area was an ideal area for cement manufacture due to the easily accessible raw
materials needed, such as clay and limestone. Limestone was quarried from several areas on the site
to depths where the bedrock became unsuitable for cement making. Over time, the quarries partially
filled with water following the suspension of quarrying operations. As determined from chronologie
photos (Site Investigation and Protocol, Layne GeoSciences), Blue Waters Pond existed by 1950, Arch
Poad was an active quarry during the mid to late 1950's, and Area "CO was an active quarry during the
late 1950's and beyond.
Prior to 1969, the cement manufacturing process reincorporated most of its waste kiln dust back into
the finished product. Unusable dust was disposed of on-site. Cement industry changes in the late 1960's
led to a significant increase in the quantity of waste kiln dust generated. By 1969, operators in the
cement industry concluded that the high source of alkalis from the kiln dust caused degradation of the
concrete due to the ocaurence of aggregate blowouts. This condition was unacceptable to cement
consumers. In response, Lehigh had to limit the amount of kiln dust in the product to achieve a less
than 0.6% alkali conteat and large amounts of waste kiln dust had to be disposed.
Problems with the site were first identified in 1981 during a routine hydrochemical test of the Blue
Waters Pond. The results of the test indicated that the pond water was highly alkaline. Lehigh had
installed an overflow control structure at the southeastern comer of Blue Waters Pond. The control
structure had been constructed because the Iowa Department of Transportation altered drainage
patterns in the area which resulted in large volumes of water entering Blue Waters Pond. The flow
control structure allowed water from the pond to be discharged directly to Calmus Creek to eliminate
possible back-flooding of equipment critical to Lehigh's operation.
The result of testing in 1981 indicated pH values of approximately 10.6. State regulations oaly allow for
the discharge of water with a pH value up to 9.0 into Class -B" warm water streams. Lehigh was
instructed not to allow overflow until the alkalinity could be reduced.
At this time, Lehigh hired the consultaot, Wallace, HoUaod, Kastler, Schmitz and Company (WHKS)
of Mason City, Iowa to determine the source of high pH waters. Lehigh also performed their own
chemical tests and determined that CKD and cement were the predominant sources of elevated pH.
WHKS obtained and anaJyzcd 28 water samples from various surface water sources in order to
determine the source of the elevated pH in Blue Waters Pond. The results of the WHKS report
identified three potentiallOurces, of which Arch Pond contnouted the most significant quantities of high
pH water to Blue Waters Poad. The high pH of Arch Pond was attnouted predominantly to direct
contact with em. .
The WHKS report recommended options to reduce or contain high pH site waters. Lehigh chose to
tr8D.'ifer the water from Blue Waters Pond to Area "CO Pond and retain the water behind two earthen
dikes. These dikes have since failed due to high rainfall.
In 1984, the State of Iowa (Department of Natural Resources) conducted a Comprehensive
Work/Quality Assurance project at Calmus Creek, which is located apprcmmately 1,000 feet south and
downgradient from the Blue Waters Pond. This investigation found that surface water contamination
was directly related to the Lehigh facility. According to this report, a highly alkaline discharge of the
7
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Blue Waters Pond uno nearby Calmus Creek via the tiJe draiD outJet southeast of the plant is believed
to have contaminated Calmus Creek. .
The Blue Waters Pond overflows during heavy rainfall (IDOT drains flow into Calmus Creek from the
adjacent highway). The Arch Pond ilnmediately west of the Blue Waters Pond would contnoute aD
unknown quantity of runoff from the eastern half of the plant. The discharged water had a recorded
pH of 11.4, total dissolved solids of 4,700 mg/l, including 2,000 mg/l potassium, and 829 mgfI sulfates.
Chromium and other hazardous substances were not analyzed during this IDNR investigation.
The biological quality of Calmus Creek was found to have deteriorated from emuents from Lehigh and
Northwestern States Portland Cement Company sites. Because of the deterioration of the chemical
balance in Calmus Creek and the quarry ponds, the number and variety of fish and benthic orgJlni~m~
were found to be substantially reduced downstream of ttte tile drain outJeL (See Calmus Creek Water
Quality Study, 1984, University Hygienic Laboratory). CaImus Creek also discharges into the
W"IDDebago River, approximately l.SOO feet from the tile drain outlet. As a result of this study, Lehigh
was required to eliminate the discharge into Calmus Creek.
To control overflow from Blue Waters Pond a control structure was placed in the southeast comer to
control water elevation; dikes were constructed to separate Arch Pond, Area -CO Pond, and Blue Waters
Pond; and an aboveground piping system was installed which pumps water from Blue Waters Pond into
Area -CO Pond. Also, Lehigh proposed construction of a lined ditch to channel the surface runoff
collected by the mOT drain system from the adjacent highway (on Lehigh property) back into the
mOT tile drain loc:ated southeast of the Blue Waters Pond.
Lehigh's long-term goal was to eliminate Blue Waters Pond by backfilling and regrading the area.
Lehigh retained a consulting firm in 1985 ( R.E. Wright and Associates) to conduct a hydrogeological
investigation of the site. The firm installed three on-site monitoring wells to characterize the chemistry
of the groundwater and its flow parameters. Monitoring and sampling of these wells has shown that
Arch Pond is hydrologically connected to Blue Waters Pond. The study found significant elevations in
pH and in the levels of potassium, sodium, silicon, sulfates, total dissolved solids, and total organic
carbon. Since this finding, compacted waste kiln dust is being disposed of into the West Quarry, which
is clay-lined.
ID 1987, the EPA hired a consulted, Ecology and Environment, IDe. to study the area. They visited the
site in April, 1987. E & E noted in this investigation that the above-ground piping system was leaking
in severalloc:ations between Area -CO Pond and Blue Waters Pond. Also, water had still been observed
returning back to Blue Waters Pond via seepage in the two dikes used to contaiD Area -C" Pond and
by groundwater flow through joints in the intervening bedrock.
A summary of the E & E Report includes the following comments: -Past investigations conducted
internally by the Lehigh facility and the State of Iowa have shown that on-site contamination exists and
contaminants are migrating to groundwater sources and Calmus Creek. The April 1987 field work
conducted by E & E/FIT included kiln dust/sediment, surface water, and ground water sampling. This
investigation has confirmed that the on-site quarry ponds and groundwater are contaminated locally and
have the potential to migrate off-site"
The E & E investigation found waste kilD dust to have a pH of 13.0 units. The measured pH levels in
water from the on-site quarry ponds and monitoring wells ranged from 7.19 to 12.04. Other constituents
of the kiln dust included arsenic, chromium, lead, zinc, and sulfates. E & E noted that these kiln dust
constituents are -roxic and persistent-..
-Seepage bas occurred from the quarry ponds and is contaminating the groundwater. The highest pH
value detected in the on-site groundwater was 12.04 units. Sampling also indicated a contamination
8
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threat to Calmus Creek and the Wmnebago River, which is located within 1,SOO feet of the site.
However, contamination could occur during high intensity rainfall events, groundwater infiltration, and
flooding. The potential exists for human and biological exposures to the hazards present at the Lehigh
site:
In 1987, Lehigh hired R. E. Wright and Associates to present a plan for the elimination of the Blue
Waters Pond discharge. In an excerpt taken &om the R. E. Wright executive summary: 'The project
will involve reducing or eliminating the volume of water with high alkalinity levels which seeps into Blue
Waters Pond &om Arch Pond. This will be accomplished by constructing a slurry wall bctwccn Arch
Pond and Blue Waters Pond, and grout curtain (in the future, only if required):
The second objective of the project was to eliminate the runoff of storm water &om 1-65, which
discharges into Blue Waters Pond, in order to prevent future ovcrOo~. This was to be accomplished
by redirecting the storm water drainage &om 1-65 to discharge into the 25th Street Ktorm SCWCI'. The
third task outlined was to dispose of existing high alkaline water in Blue Waters Pond by pumping water
through an inigation system into Area .CO Pond.
These steps were implemented by Lehigh. However, due to the persistence of high pH values on site
and the results of the E & E study, Lehigh was evaluated in 1987 and 1988 for National Priorities
Listing. Lehigh was proposed for the NPL in 1988. In August, 1990, Lehigh was made a F"maI NPL site.
In 1989, Lehigh hired Layne GeoSciences to perform the Remediallnvcstigation{Feasibility Study for
the site. Nine monitoring wells were installed on the site, one a nested well. The nested well would
allow for sampling the groundwater &om two aquifers, or water-bearing units. As the investigation
proceeded, two additional shallow monitoring wells were installed east of Highway 65, on Lehigh
property (F'18W'e 3). These wells were installed at the request of IDNR to determine pH as well as any
other inorganic contaminant movement eastward onto the Ume Creek Nature Center.
On June 20, 1990, the first round of sampling was performed. Elevated pH values, tOtal dissolved solids,
and similar contaminants as prior studies were found in the groundwater and surface water. The pH
values (field measurements) ranged &om background to as high as 11.44 in MW-9. Total dissolved
solids in this well were also the highest, at 7000. The pH values in the ponds on site were higher, up
to 13.0 in Arch Pond, with TDS levels at 11000. It was apparent that Lehigh's previous work to
eliminate the source of high pH and TDS was not working.
On July 19, 1990, the second round of sampling was performed. The results of this sampling round were
comparable to the first round; pH values were still elevated, as were total dissolved solids, sulfates and
in some monitoring wells, inorganic constituents. MW-9, for example, had a pH of 11.43 (field) and
TDS of 9700. Arch Pond had a pH of 13.15, with TDS levels of 10000.
Further sampling was performed at the Lehigh site area in October, November, and December 1990.
Similar results as the first two rounds of sampling were discovered. In addition to these results, the two
monitoring wells installed east of Highway 65, MW-1O, and MW-11 were showing little impact &om pH
01 inorpnics.
In the fall of 1990, it was also determined that the Lime Creek Nature Center needed to be investigated
(or the same contaminants as the Lehigh site. Lehigh had (ormerly owned property at the Nature
Center and a large quantity of cement kiln dust had been dumped in abandoned quarries on Nature
Center property. The areas of greatest concern were a Ouany Pond area on the western edge of the
Nature Center, and an area knOWD as the -Badlands., which contained perhaps 40 aacs of CKD.
In November 1990, at the request of IDNR, Lehigh agreed to a limited investigation of the Ume Creek
Nature Center. This involved the inst:tllation of four monitoring wells, sampling the existing weD OD site,
9
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Figure 3:
Monitoring WeD Locations. Lehigh
10
POOR QUALITY
ORiGiNAL
-------
2.4
and sampling the cement kiln dust and surface water on site. The results of the Lime Creek Nature
Center investigation are discussed later in this report.
2.2
Hi~ehts of Communitv Participation
The Remedial Investigation and Fe&s1Dility Study Reports aDd the Proposed Plan for the Lehigb site
were released to the public for comment May 20, 1991. These two documents were made available to
the public in the administrative record maintained in an information repository at DNR Records Center,
Sth floor, WalJace Building, 900 East Grand, Des Moines, Iowa, and in the Mason City Public Library.
The notice of availability for these two doc:uments was published on May 20. 1991 in the Masoa City
Globc-Gazctte. A public comment period OD these documents was held from May 20, 1991 through
June 19. 1991. Also, a public meeting was held on June S. 1991 at the Mason City Public Libruy. At
this meeting, representatives from the DNR, EPA and LPCC discussed the site and the selected
remcdiaJ alternative. QUcsUODS from the media were answered rcgarding the IC\'erity of the cDstiDg
problem at LPCC and the potential for future hazards at the sitc. A response to comments receiYcd
during this period is included in the Responsiveness Summuy, which is part o( this record. This
decision document presents the selected remedial action for the LPCC site in Mason City, Iowa, choscn
in accordance with CERClA, as amended by SARA and, to the extent practical, the National
Contingency Plan. The decision (or this site is based on the Administrative Record.
2.3
Scope and Role of Response Actions Within Site Strat~~
The selected response action addresses the principal threats of surface water. groundwater
contamination and the source of water contamination. Based on past invcstigatioDS of the site, as well
as the Remedial Investigation, the source of contamination is the cement kiln dust disposed of in thc
CKD Reclamation Area and in Area .C" Pond. Of particular concern is its impact on the groundwater
and on Calmus Creek. The kiln dust would be sufficiently isolated from water in the selected alternative
to minimize production of contaminated water. Any contaminated groundwater which is produced, as
weD as existing contaminated groundwater and surface water. will be removed, treated and discharged,
thus prevcnting off-site migration of contaminated water.
The response actioDS selected in this ROD address all principal threats posed by this site and are
intended to constitute final remedial action for the site.
Summarv of Site Characteristics
The major concern at LPCC is contaminated surface water and groundwater as a result of contact with
waste cement kiln dust in the site ponds and the CKD Reclamation Area. The kiln dust is composed
of a major cement constituent, calcium oxide (CaO). which reacts with water and releases hydroxide ions
(OH-) into solution. The hydroxide ion concentration directly controls the pH level of an aqueous
solution. Local groundwater and surface watcr havc been impacted by high pH lcvels, and by an
ina-case in total dissolved solids content, as well as elevated concentratioDS of potassium, sulfate, sodium
and other relatively nonhazardous parameters. Trace amounts of heavy metals have also been detected
sporadicaDy. Of the contAminAnts identified, arsenic; lead and chromium arc suspected carcinogens.
Levels of metals found in soil/sediment samples are not considered to be significantly different than
background soils. The kiln dust at the Lehigb site is a RCRA special study waste, not a RCRA
hazardous waste. Water at the LPCC site having a pH value ~xCC'~Ai"'g 12.S would exceed the RCRA
aiterion for corrosivity and be considered a RCRA hazardous wastc.
Impacted groundwater has been found to exist at the site but docs not appear 10 have significantly
migrated to the bedrock underlying and adjacent to the site. The degree of impact has been shown to
Icsscn with depth. No significant off-site groundwater contamination has been found. ragure 4 is a
groundwater Dow map showing typical Dow conditions. Groundwater Dow on site appears to be
southeastward to either the Calmus Creek or the Winnebago River. Potential pathways of groundwater
11
-------
,
.
.
MW90-7S
1 125.82' ~\
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\
Figure 4:
GrouDdwliler Flow Trends. OeL 1m
12
.
(
POOR QUALITY
ORIGINAL
-------
.
migration exist via thc upper bedrock (Devonian aquifcr).
Thc Devonian aquifcr yiclds modcratc amounts of watcr to wells. Devonian wclls produce watcr
primarily from thc upper weathcred portion of the rock and solution-enlarged fractures. Nearby wells
which draw watcr from this aquifcr include 11 privatc wells about a mile north of the sitc and 1 weD
in the Lime Creek Nature Center about a mile east of the site (See F"JSW'e 5 for domestic: weD
locations, FJSW'e 6 for Mason City municipal weD locations). Wells with higher capacity in the area are
c:ompleted in the Cambrian Jordan Sandstone at depths greater than 1200 feet, including the LPCC plant
well and Mason City water supply wells. These deep wells are typic:aUy unc:ased though the Devoaian
aquifer, allowing Devonian water to cnter the weD, although this is most likely a small portion of the
total weD capacity.
2.S
Summary of Site Risks
The immediate concem on the Lehigh site is environmental with the public: health risk DOt as great.
The impact on Calmus Creek and nearby habitat was examined in a water quality study done in 1984
which indicated that point source disc:harges from both Lehigh and Northwestern States Portland
Cement Company had a substantia] negative impact on water quality and the integrity of the biologic:a1
community. The instream pH value of 10.2 measured during this study exceeded Iowa Water Quality
standards. There wcre also ina-cased levels of ammonia nitrogen, turbidity, sulfate, sodium and
potassium measured downstream of high pH disc:harges from Lehigh.
Sedimentation on the stream bottom from waste kiln dust and precipitation of c:alcium c:ompounds
greatly affected the biologic:a1 community. The benthic: population was almost non-exWent in the
affected reach. FISh populations were reduced with very little, if any, spawning activity oc:c:urring in the
area. A similar study done by EP A in 1989 concurred with these results.
The situation in Calmus Creek has not changed substantially since 1989. In fact, rec:cnt rainfalls have
caused more overflows of Blue Waters Pond into Calmus Creek. Lehigh is c:urrentJy under order to
stop this discharge and has been granted temporary permission to acid-neutralize Blue Waters pond
water and discharge this treated water to Calmus Creek. Due to the high level of total dissolved solids
in the treated water, however, Lehigh will need to discharge to the Wmnebago River (with higher stream
Dow rates) in the long-term.
The U.s. Public Health Service Agency for Toxic Substances and Disease Registry (ATSDR) conducted
a preliminary Health Assessment for the Lehigh site. A TSDR concluded that the site is of potential
health concern because of the potential risk to human health resulting from possible exposure to
hazardous substances at concentrations that may result in adverse health effects. The A TSDR report
expressed a concern for potential human exposure to arsenic, chromium, lead, sodium, sulfate, and
elevated pH via ingestion of groundwater from on-site and off-site private wclls. Also human exposure
to elevated pH may oc:c:ur and may have oc:c:urred in the past via dermal c:ontad, oc:ular c:ontact, and
incidental ingestion of on-site soil, sediment, surface water and groundWater; and via inhalation of
reentrained dust. Human exposure pathway of concern includes the sodium and sulfate C:ODc:cntrabons
in the groundwater which may be detrimental to high risk populations.
A Baseline Risk Assessment was conducted as part of the remedial investigations and is included in the
Adminictrative Record as I separate report. This Baseline Risk AssessmeDt provided I basis to assist
in the development of remedial aJternatives. It as~ssed only the hazardous substances listed in Table
I. . The Baseline Risk Assessment did Dot consider pH, sodium, potassium, sulfate, or total dissolved
solids which are the primary parameters impacting water quality at the site. These parameters are
naturally occ:urring, often at relatively high concentrations; are not particularly toxic; and, as a result,
do not fit into the risk ~ssment process. With this in mind, the Baseline Risk Assessment indicated
that:
13
-------
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.... ,".
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}'ia:ure 5:
Loc:a1iOD of Domestic W c11s
14
fOOR QUALITY
OR!GINAL
-------
.\
EXPLANATION
. -MASON CITY WELL
.
1-.&
SCALE
Fiaure 6:
Municipal WeD Locations
15
EOOR QUALITY
ORIG!NAL
-------
1)
2)
There are no complete exposure pathways identified for contaminants in the soil or air.
The surfacc water docs not pose any adverse health exposure potential to the general public..
Neutralizing and monitoring water quality on the Lehigh site ponds before releases should be
continued. .
3)
The only potentially complete exposure pathway for the Lehigh site is through groundwater in
the bedrock.. There is no current or anticipated adverse cxposure potential for the surrounding
public and private welJs in the near future.
4)
The site ponds at Lehigh are not a present threat to the public health or welfare of the Muon
City area.
Potential risks from drinking site groundwater were calculated in the Baseline Risk Assessment and are
summarized in Table I. These hazards were based upon .potential. consumption of water with the
Reasonable Maximum Exposure contaminant conccntrations found in on-site monitoring welJs. In
reality there is no current consumption of this impacted water. The foUowing paragraphs explain the
information presented in Table I.
Reference doses (RIDs) have been developed by BPA for indicating the potential for adverse health
eff~ from exposure 10 chemicals exhibiting noncarcinogenic effects. RIDs, which are expressed in
units of mg/kg-day, are estimates of lifetime daily exposure levels for humans, including sensitive
individuals, that are not likely to be without an appreciable risk of adverse health effects. Estimated
intakes of chemicals from environmental media (e.g., the amount 01 a chemical ingested from
contaminated drinking water) can be compared to the RID. RIDs arc derived from human
epidemiological studies or animal studies to which uncertainty factors have been applied (e.g., 10 account
for the use of animal data to predict effects on humans). These uncertainty factors help ensure that the
RIDs will not underestimate the potential for adverse noncarcinogenic effects to ocau.
.,
Potential concern for noncarcinogenic effects of a single contaminant in a .single medium is expressed
as the hazard quotient (HQ) (or the ratio of the estimated intake derived from the contami,u'"f
concentration in a given media 10 the contaminants's referencc 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 multiple contaminant exposures within a single medium or across media.
HI values less than one arc aa:cptable.
Slope factors (SFs), also called cancer potency factors (CPFs); have been developed by EPA's
Carcinogenic Assessment Group for estimating a::ess lifetime cancer risks associated with exposure 10
potentially carcinogenic chemicals. SFs, which arc expressed in units of (mg/kg-dayr1, arc multiplied
by the estimated intake of a potential carcinogen, in mg/kg-day, to provide an upper-bound estimate
of the a::ess lifetime canccr risk associated with eXposure at that intake level. The term "upper bound.
reflects the conservative estimate of the risks calculated from the SF. Use of this approach makes
underestimation of the aCtUal cancer risk bigbJy unlikely. Slope factors are derived from the results of
human epidemiological studies or chronic animal bioassays to which animal-ta-human extrapolation and
unccrtainty factors have been applied.
Exc:ess lifetime caDccr risks are determined by multiplying the intake level with the Slope Factor. These
risks arc probabilities that are generally expressed in scientific notation (e.g., 1x1~). An a::ess lifetime
cancer risk of a 1x1~ indicates that, as a plausible upper bound, an individual has a one in one million
chance of developing canccr as a result of site-related exposure to a carcinogen over a 7O-ycar lifetime
under the specific exposure conditions at a site.
16
-------
m summary, Table I shows that long-term consumption of the impacted site groundwater would pose
a slightly elevated risk since the HI valuc is greater than one. Regardless, thc selected remedy will
prevcnt off-site migration of any impacted groundwatcr and consumption of contaminated watcr will not
occur.
Table I- A shows a tabulation of the cancer risks associated with each chemic:.a1, and the total pathway
cancer risk for ingestion of contaminated groundwater. Cancer risk has been calculated by multiplying
the chronic daily intake by the Slope Factor for the chemical. Risk is expressed as an upper-bound
estimatc of thc additional cancers which could result &om lifetime exposurc to the contAmiftAftt For
example, a 5 x 10-4 cancer risk meaDS that 5 individuals in a population of 10-4 (10,000) could develop
cancer as a result of lifetime exposurc to a particular level of thc chcmical in question.
Thc bottOil& of Tablc I shows a summary of the risks discussed above. These risks were all calculated
with present land use in mi:d, assuming futurc land use at Lehigh will not change. It was also assumed
that thcre would be no anticipated future residcntial impact &om contAmiftjlftt!: at the Lehigh site.
The primary complete exposurc pathway was through groundwater. Of all the groundwater sampling
data, lead had thc highest lcve~ 0.52 mgfL, which caused its arithmctic mean and 95% confidcnce limit
based on the mcan to be higher than what is probably representative at the site. The highest cancer
risk slope factor comes &om arsenic. The slope factor for lead is much lower, and therc is no
carcinogcnic slope factor for chromium, which is not considered an oral carcinogcn. m an Appendix
at the back of this report, thc monitoring well and surface watcr .sampling results can he found.
The total cancer risk exc:eeds thc goal of cancer risk below 1 x 10-6 by a factor of roughly 1000. Thcre
are levels of uncertainty built into slope factors and into the calculations to account for a fairly large
margin of safety. As mcntioned earlier, evcn with the slightly increased cancer risk, thc selected rcmedy
will prcvent off.site migration of any contaminated groundwater and its subsequent consumption.
The Baselinc Risk Assessment did not specifically addrcss thc major paramcters affecting watcr quality
of the LPCC site. rlgW'es 7 and 8 illustratc the concentrations of pH and total dissolved solids (TDS)
found in groundwatcr throughout thc LPCC site. Sodium concentrations have also been found in high
lcvels. National secondary drinking watcr regulations set non-cnforceablc limits for CODtAmiftAftts in
drinking watcr which may affect the aesthctic qualities or thc public's acceptance of drinking water (c.g.,
tastc and odor).
These secondary maximum contaminant lcvels (SMCLs) have been established for pH (6.5-8.5), sulfatc
(250 mg/l) and TDS (500 g/l). In addition, a guidance of 20 mg/l sodium exists for peoplc on low-
sodium dicts. Significantly elevated Icvels, much in excess of thc SMCLs, have been idcntified in thc
groundwater and surface watcr at the site. The elevated pH levels have been the primary concern
associated with the LPCC site ponds. J,.cvcls of pH in excess of 12.5 have been found in site ponds (the
b
-------
.-.
'7.G-pH
tOO-SPECIFIC CONDUCTANCE
(umhOI em)
Flaurc 7:
GroUDdwalC1' pH. OeL 1990
/
18
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ORIGINAL
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['[oJ'; r""5"O'OO )!~:;:'",-,,~~ ~ ~~':T ,c.!---~.~..~'~'\~ I:~ .
a:1'..-.2, ~,~. ..,_.r';::"~.'10~:~~'''~~''~.''i:'~~;':'',.,'' --- I ",'1':
':'V ...i-f OND !JI.. --. r "'''''''' .- . , - '- ~ I I.
:"":-~:;'ARCH P -:. '~'~'. .--' '.Ww'-~ "", '. S POND .~ 'I ~
-.. -' -':0. ..: '=-WO.. ...~ BLUE WATER ::"'. , :. '~
': -'><- """" "', '--:"-,,,,: =. , r i" .
-, "-'''''---''', '~" 00 -,. <-'1;s.-' .~ ' 6100 ." '; \;-;; ~': '
::y..r :'~:Xm \~~-?f.:~ ot~~,>.,,~ j ~. 'Vt1t
' '.~ ~ ':-" ' ,- -"""':: I .-..." ;,. tr:J,.: '~"':
' ..... ' . ' --as -', '=-. 'l-- . 500. .-"'i!. .JOO,- '01
't ';'\1"~~ \\ :,:;;j;r'~i fj'''' ~ C', ::.~. 4r.. j.'[, ;.:r.; 6800 ~( :1w~;.
1 \~ .. 1.00 ,(-...,..:~~:,,,: {'-;iiwoo-ss j;"~iiiw-.o::is' 0"...:-' :. ~. r, A~'I.io
~~- .... .. .,------:-. " '. '.. , "'.,--- " ",\. ,
:-j-.. :-':":, \ :0--. L.w II. .; --~: ~;. 1'_"'."--'''''.""... MW8o-2D.O,-._------ ". 111670
t ~l '-o.Io!:'/~' MW80-4S ~ -. ../ , ':t;'.. --";'.. w_- 0'''-, '... iJ, I , ,
"co. -, -'oDd!'- (-; ':..' ~'>. fiI' 6 150 I "w. i~ ,.,
' .... 1., - ~ "'" I ~v .. .' --.. . ','.-.
I "0-." : " " . , -", ' '.- ,
2"0 1500 FT -~" "'" " ',\: '-- .::: '-700"
o . , -, _....~~~-- -'" - _00-1. C
I .~=. '.. J..,-... 1 ----.
~i--' . ~~.- . - .-
. Ivcd Solids. Oct. 1990
Groundwater Total D1SSO .
19
POOR QUALITY
" ORIGINAL
.
-------
Table I
Chronic Hazard Index Calculations
Chemical m ~ CDI:RfDc
Arsenic 6.94(10-4) 1.0(10-; 6.94(10-1)
Lead 7.34(10-4) 1.4(10-; . 5.24(10-1)
Chromium(total) 3.02(10-4) 5.0(10-; 6.04(10-2)
1.2784
The chronic hazard index (HI) representing the sum of CDI:RfDc ratio is 1.2784
CDI = Chronic Daily Intake
RlDc - Acceptable Intake for Chronic Response
Summary or Assessed Risks
Exposure Pathway Caac:er Risk Chronic Hazard SubchroaJc
lades llazanllades
Ingestion or ContamiDated 1.28(10.')
Groundwater 1.%784 1.2.S13
20
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Table I. A
Cancer Risk Estimates
Chemical Cbl'ODic Dally IDtake Slope Factor Cbemlca1-8pecU1c
lDI/kI-day (ma/k8-day).1 Risk
Exposure Pathway: IDgestion or contaminated lP'Oundwater
ArseDic 6.94(1G- 4) 1.8(1<1') 1.25(IG-"')
Lead 7.34(1G-") 4.0(1G-2) 2.94(1G-5)
Chromium 3.02(1G-") NA NA
Total Pathway Rlsk=
1.28(1G-3)
Exposure Pathway: IDbalation or blowing dust, current conditions
There is DO available data on % solids in the CKD materiaJ at the Lehigh site, thus no estimate can be made
as to effects of blowing dust. II is presumed 10 be negligible under cunenl conditioDS. Similar samples taken
at Ume Creek reveal no high levels of metals in the dust and the dust at the Lehigh site is largely under water.
Exposure Pathway: Ingestion or contaminated dust, current conditions
There is DO wormation regarding average .soir concentratioDS in the Lehigh CKD. There were EP Tozicity
tests performed on the CKD, however, the data &om the EP Toxicity tests does not translate into an estimate
of exposure due to ingested soils.
21
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2.6
Desaiotion of Alternatives
The alternatives for soil and groundwater cleanup have been evaluated and listed below.
Remedial ActIon Altera.atlve 1 - No Action
Remed1a1 ActIOb Altenuatlve 2 - Drainage of quarries and water treatment.
Remedial ActIon Altera.atlve 3 - CKD Isolation and CappiDg, including RAA-2 actMties.
Remedial ActIon Altera.atlve .. - Waste Stabilization, including RAA.2 activities.
Remedial Adion Altenaatlve 5 - On-Site Engineered Landfill, including RAA.2 activities.
Alternative 1. No Action
The no action alternative includes allowing conditions at the site to remain as they exist today. Pond
water would be pumped between ponds. Existing dikes and berms would attempt to contain high pH
water in Blue Waters Pond. Evaluation of this Alternative is required by the National Contingency Plan
(NCP) and also provides a baseliDe of comparison for the other alternatives. ARAR.'s would not be
attained.
There would almost no cost associated with this alternative.
Alternative 2- Draina~e of quarries and water treatment
This alternative involves the draining and treatment of water from the site ponds. Thc draining of the
ponds is expected to create a groundwater sink which should extend under much of the plant area,
therefore treating the shallow site groundwater. CKD leachate would continue to enter the groundwater
system, through the CKD Reclamation Area and the site ponds, but would be captured and treated.
This alternativc includes obtaining an NPDES permit 10 dischargc either to Calmus Creek or the
Winnebago River, a drain system to COned groundwater which seeps into Arch Pond from the CKD
Reclamation Area, and installation of three monitoring wells around the CKD Reclamation area to
determine whether the base of the Area is saturated. Arch Pond (the sump area) will need to be
pumped indefinitely, and watcr treatment as long as necessary.
.\
The estimated present worth cost of this alternative is Sl.5 million and would take one 10 two years to
implement.
Alternative 3- CKD Isolation and CaP.pini
This alternative would result in thc remediation of the Plant area and would attain all applicable
ARARs. This alternative would include all activities of Alternative 2.
In this alternative, additional activities would include: Consolidation of CKD in the drained Area .C"
pond and the CKD sediment in Blue Waters and'Arch pond. The consolidated CKD would then be
covered with an engineered clay cap. Construction of a drain system to collect groundwater ICCpage
from the CKD Reclamation area into Arch Pond. Consolidation of surficiaUy deposited CKD in the
Reclamation Area, regrading of this area, and construction of an engineered clay cap 10 limit infiltration
of precipitation. A network of three monitoring wells would also be installed around the CKD
Reclamation Area to determine whether the base of the CKD in the area is saturated. If so,
appropriate steps will be taken to dewater the area. F'malIy, continued groundwater monitoring and
continuous operation of the Arch pond sump and water treatment, if necessary.
,
The .estimated present worth cost of Alternative 3 is $3.4 million and would take approximately three
years to implement.
22
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Alternative 4- Waste Stabili7J1tion
The succ:cssfu1 implementation of this alternative would result in the remediation of the plant area and
attain all ARARs and provide a permanent remedy. The remediation would be aa:omplished by
rendering the CKD essentially inert through stabilization. This alternative would include all ac:tMties
of Alternative 2 In addition, there would be laboratory kiln dust/fixative tests performed (0 establish
the most effective combinations and concentrations. The waste kiln dust would be stabilized ud
solidified with a fixative agent introduced through kiln dust augeriag, or excavation and redeposition.
A groundwater seepage collection gallery west of Arch Pond would be constructed to collect water &om
the CKD Reclamation Area. along with a network of three monitoring wells around the prescnt CKD
Reclamation Area (0 determine the effectivencss of the stabilization process. Continued groundwater
monitoring and pumping of the dewatered ponds would also be part of this alternative.
The estimated prescnt worth of Alternative 4 is $25.3 million and would take approximately three years
(0 implement.
Alternative So Pond Drainaee and On-Site Landrill Construction
This alternative would result in the total remediation of the site through the removal and treatment of
CKD effected surface water and groundwater in conjunction with the construction of an engineered
CKD storage facility. This landfill would be in compliance with state laws. Alternative S includes all
activities of Alternative 2 plus: Engineering of a landfill capable of containing and isolating all the CKD
present in the CKD Reclamation Area and Area .C" pond, as well as CKD sediment in Blue Waters
and Arch Ponds. Following drainage, the CKD prcscnt in Area .C" pond and the CKD sediment in
Arch and Blue Waters ponds would be removed and transferred to this on-site engineered landfill
storage facility. Continued pumping of in110wing and surface water from the drained ponds, or following
aquifer restoration, allowing them to rill with water. Continued groundwater monitoring.
The estimated present worth cost of this alternative is $19 million and would take approximately three
years to implement.
27
Summary of Comparative Analysis of Alternatives
The treatment of impacted groundwater and surface water is a common remediation denominator to
several of the alternatives. Although the actual quantity of water to be treated varies somewhat between
individual alternatives, treatment processes and costs would be similar. The major differences in
alternatives are the steps taken (if any) beyond drainage and water treatment.
A comparative analysis of each alternative against the following nine aitcria has been made. Thcsc nine
aiteria are categorized into three groups: threshold aiteria, primary balancing aiteria, and modifying
aiteria. The threshold aiteria must be satisfied for an alternative to be eligible for selection. The
primary balancing aiteria are used (0 weigh major tradeoff's among alternatives. Generally, the
modifying criteria arc taken into aa:out after the public comment is received on the Proposed Plan.
A glossary of the nine criteria follows.
GlossarY or Evaluation Criteria
'lbn:shold Criteria:
Overall ProtecaDn 01 Hunuzn Health tIIUI Environment addresses whether or not a remedy provides
adequate protection and describes how risks posed through each pathway are eliminated, reduced, or
controlled through treatment, engineering controls, or institutional controls.
23
-------
Compliance with Applicable or Releww and AppropriaJe Requirements (ARARs) addresses whether or
Dot a remedy will meet all of the ARARs of other Fcdcral and State environmental statutes and/or
provide grounds for invokiag a waiver.
Primary BalaDdDg Criteria:
Lon,.. Tenn Effectiveness and PtmUllWlCe refcrs to thc magnitudc of residual risk and the ability of a
remedy to maintain rcliable protection of human health and the environmcnt over time once cleanup
goals have been met.
Reduction of Toxicity, Mobility, or Volume through T~atment is thc anticipated performance of the
treatmcnt technologies that may be employed in a remedy.
Shott- Tenn Effectiveness refers to the speed with which the remedy achieves protection, IS weD IS the
remedy's potential to creatc adverse impacts on human health and the environment that may result
during the construction and implementation period.
lmplementability is the tcchnica1and adminiufative feasibility of a remedy, including the availability of
materials and services needed to implement the chosen solution.
Cost includes capital and operation and maintenance costs. Present worth costs are based upon capital
costs plus the present sum necessary for operation and maintenance over a given period and a discount
rate of 5% (before taxes and after inflation).
Modifying Criteria:
Support Agency Acceptance indicates whether the EP A CODcurS with the preferred alternative.
Community Acceptance will be addressed in the Record 0/ Decision of the public comments rcc:cived OD
the Remedia/lnvutigatjonjFeasibility Study and the Proposed Plon.
Overall Protection of human health and the environment
The No Action alternative (Alternative 1) is not protective of human health and the environment because it does
not address the present overflow problems of high pH and high TDS (total dissolved solids) water into Calmus
Creek. It does not provide for any site remediation, and therefore could result in the deterioration of site and
off-site environmental conditions. It does not address contamination in the surface or groundwater.
The Drainage of Quarries and Water Treatment Alternative (Alternative 2) does address current site surface
water and shaDow groundwater contamination. This alternative would also lower the water table in the vicinity
. of the site, decreasing the amount of CKD in contact with the groundwater system. However, this alternative
is Dot protective of human health and the eDvironment because it does Dot permanentJy address CKD on site,
which is the source of contAminAted seepage flowing into Arch PoneL
The CKD Isolation-c.ppiog (Alternative 3), Waste Stabilization (Alternative 4), and CKD Isolation in an On-site
Landfill (Alternative S) an protective of human health and the environment because they will drain the
contaminated surface (and some groundwater) IS weD as treat the CKD and preveDt it ham interacting with
water on the site, at least in a way that would cause further leaching of high pH water onto the site. With the
CKD Isolation and On-Site Landfill Alternatives, it will be necessary that a long-term monitoring program e.xist
to prevent against future threats to human health or the environment.
24
(
-------
Compliance with ARo\Rs
The No Action alternative (Alternative 1) would not comply with.ARARs (or the discharge to Calmus Creek
or (or surface water and groundwater contamination. The Drainage of Quarries and Water Treatment
alternative (Alternative 2) would address surface water and groundwater ARARs (or existing site conditions, but
may not address ARARs (or future contamination caused by leachate from the CKD Reclamation area.
The CKD Capping-Isolation alternative (Alternative 3), Waste Stabilization alternative (Alternative 4), and On-
Site Landfill alternative (Alternative s) aU would comply with ARARs by stopping the untreated disdwges to
Calmus Creek and to groundwater, and by addressing contaminated groundwater through drainage o( the site
ponds. The Waste Stabilization alternative (Alternati~ 4) would permanently address ARARs for future
contamination.
Lolli-term effectiveness and permanence
The No Action alternative (Alternative 1) and the Drainage of Quarries alternative (Alternative 2) lack long-term
effectiveness and cannot be considered as permanent cleanup actions. .
The CKD Capping-Isolation (Alternative 3) and On-Site Landfill (Alternati~ s) alternatives ha~ effectiYeness
and permanence but require assurances (or continued pumping and groundwater monitoring to maintain long-
term compliance with this aiterion. The Waste Stabilization alternative (Alternative 4) would not require long-
term pumping but would provide for monitoring at the Plant site, as weD as permanently treat the waste.
Reduction of toxicity. mobili~. and volume throuih treatment
The No Action alternative (Alternative 1) would not reduce the toxicity, mobility, or volume of the contaminated
materials. All other alternatives include treatment o( water prior to discharge. The Drainage of Quarries and
Water Treatment alternative (Alternative 2) would reduce the volume of the contaminated water, but would not
reduce the toxicity or mobility of contaminants that would stil1 seep from the CKD Reclamation area into Arch
pond. The groundwater would still be impacted ~ time due to this seepage.
The Waste Stabilization (Alternative 4), CKD Isolation-Capping (Alternative 3), and On-Site Landfill (Alternative
S) alternatives all reduce the volume of groundwater and mobility of contaminants to similar le~1s. All three
of these alternatives accomplish this by treatment of existing contamination and drainage to prevent further
contamination. The groundwater contamination would also be greatJy diminished and future discharges to
Calmus Creek eliminated. Of all the alternatives, Waste Stabilization (Alternative 4) would best accomplish the
goal of reduction o( mobility.
Short-term effectiveness
The No Action alternative (Alternative 1) lacks short-term effectiveness. The Quarry Drainage (Alternative 2)
alternative is partially effective in the short-term, since it stops the discharge to Calmus Creek and to bedrock
groundwater. It would have limited effectiveness on seeps from the CKD Reclamation Area, but should
eliminate many o( these in the short-term.
The em IsolatiOD-CappiDg (Altemative 3) would be more effective in the short-term IS well, IS it takes leas
time to implement than either Waste Stabilization (Alternative 4) or aeating an On-Site Landfill (AJtemative
S). The effect of Alternatives 3 through S on short-term groundwater remediation should be s~antia1. but
long-term groundwater remediation by Alternatives 3 through S would need to be monitored. Alternatives 3
through S iDclude drainage and water treatment. Airborne dust generated by Alternative S would be a problem
in the short-term. .
Implementability
The No Action alternative (Alternative 1) presents no implementation difficulties. The Quarry Drainage
(A1ternati~ 2) alternative presents the next easiest alternative to implement, and uses easily obtained
tec:bnologies and equipment. The CKD Isolation-Capping (Alternative 3) would require a more difficult level
2S
.
-------
. of implementation, but would have proven technology and available equipment.
The Waste Stabilization alternative (Alternative 4) requires that a usable fixative be identified and that it be
auguered and mixed into a kiln dust deposit that may be over 10 feet deep (Area "CO pond). Implementation
will be technically difficult and will require at least two years.
Engineering an On-Site Landfill (Alternative S) would not entail the incorporation of any new or untested
technologies, such as Waste Stabilization. However, the potential for failure of a landfill exists, no matter how
carefully engineered. Permits would need to be obtained, and airborne dust must be controlled to transfer the
CKD to one consolidated area. This alternative is probably the least easy to implement.
~
The costs of the alternatives arc presented in the Description of Alternatives section of this documCDt.
SUDDOrt A2encv AcccDtance
This aiterion addresses the concern and degree of support that the U.s. EPA has expressed regarding the
remedial action alternatives. The Iowa Department of Natural Resources (DNR) has reviewed the documents
pertaining to the site, including this document. The DNR has given its concurrence on the selected remedial
action.
Communitv AcccDtance
At the end of the public comment period (June 19, 1991), there were no comments objecting to the preferred
remedial alternative. This includes comments during the public hearing held June S, 1991 as well as written
comments received from May 20, 1991 to June 19, 1991.
2.8
The Selected Remedv
The selected remedy is Alternative 3, CKD Isolation and Capping, Quarry Drainage, and Water TreatmenL This
remedy entails several steps. The initial step is draining of Blue Waters, Area "CO and Arch Ponds, which would
require 1 to 2 years if a 300 to SOO gpm pumping and treatment rate could be maintained. The pumped water
would then be treated using the acid neutralization process and discharged to either Calmus Creek or the
W"mnebago River. Depending on the stream concentration limits for TDS, set by Iowa NPDES officials, further
water treatment may be required (particularly if Calmus Creek is selected as the body of water for discharge)
to lower TDS limits in acid-treated water. Further treatment would be by ion e'Jr,.hRl'Ige or reverse osmosis.
FoUowing drainage of the ponds, drainageways would be constructed in the base of Blue Waters and Area "CO
Ponds. These drainageways would be connected to a sump which would be excavated in the ponds following
sediment dredging. It is expected that shaDow groundwater will also be remediated during this drainage, due
to local shallow groundwater gradients reversing toward the quarries. At. a result of this, impacted shaDow
groundwater will be drained from the sump and prevemed from being able 10 move otJ.site.
Next, an engineered clay cap would be placed over the CKD Reclamation Area. Construction specifics of this
cap will. be determined during the design phase following proctor and permeability testing of the local clay soils.
The cap would be graded so that runoff would be directed to the sump to allow blending of surface water with
the impacted water prior 10 treatmenL The cap will be constructed 10 satisfy state landfill requirements and
reduce long-term pumping costs from inflltration of water.
CKD in Area "CO Pond and the CKD sediment in Blue Waters and Arch Ponds would be consolidated into the
drained Area "CO Pond and covered with an engineered day cap. This cap of the two CKD areas would require
approximately 80,000 cubic yards of clay-rich soil. The cap will be fmished with a sand drainage layer and
seeded topsoil layer to facilitate runoff and protect the clay.
26
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A groundwater seep collection syste:n to the west of Arch Pond will also be implemented during the initial stages
of remediation. This is designed to intercept seepage hom the CKD Reclamation Area.
rmaUy, three monitoring wells will be installed around the CKD Reclamation Area in order to assess the effects
of pond drainage and the effeaivcness of the clay cap. II the base of the Reclamation Area is found to be
saturated, dewatering wells will be installed in or below the CKD deposit. The saturated thickness is not
expected to be greater than five feet. The actual determination of the most efficient method to maintain the
dewatered state of the CKD will be determined during the remedial design phase.
The overall effect of Alternative 3 should be the isolation of the contaminant source (CKD) hom interaction with
surface and groundwater, and the removal and treatment of impacted water presently in site ponds and shallow
groundwater. Institutional controls, such as deed restrictions, will also be required on any future land sale.
The treated discharge to either Calmus Creek or the Wmnebago River will be monitored to ensure compliance
with the Iowa NPDES permiL A contingency plan will be required to ensure continued operation, including
financial assurances.
The remedy was selected hom among three alternatives that would provide for protection of human health and
the environment, comply with ARARs, reduce the toxicity, mobility, and volume of the waste through treatment,
and have both long-term and short-term effectiveness. The No Action alternative (Alternative 1) and the Ouarry
Drainage alternative (Alternative 2) would not meet all the above criteria, and so were not selected. Of the
remaining three alternatives, the CKD Isolation-Capping alternative (Alternative 3) could be implemented with
greater assurance of effectiveness, and at a substantially lower cost.
27
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THE LIME C~EK NA11JRE CENTER
The Lehigh Portland Cement Company site also includes the Ume Creek Nature Center (LCNC). This area,
although separate from the above discussed plant area, also has deposits of CKD which are in contact with water.
LCNC was investigated as part of the Lehigh RIfFS investigation. This section will briefly discuss the Lime
Creek sub-site, and evaluate the Remedial Alternative selected for the sub-site.
SITE BACKGROUND
The Lime Creek Nature Center (LCNC) is a 410 aae facility controlled by the County of Cerro Gordo and
operated as an area for outdoor recreation. It was opened to the public in May, 1984. The Center was jointly
donated by Lehigh and Northwestern States as a public recreation and nature center. Cerro Gordo County
employs several full-time employees at the center and operates a visitor center with a b"brary and numerous
DA:m"e exhibits. The Nature Center is located immediately north of Mason City, and is bounded by the
Wmnebago River to the north and east, U.s. Highway 6S to the west, and private owners to the south (F"1gUI'C
9). The Lehigh plant site is aaoss Highway 6S west of the Nature Center.
,
Portions of the current LCNC were formerly owned by Lehigh Portland Cement Company (LPCC). LPCC
transferred the property to Cerro Gordo county in 1979. During its ownership, LPCC mined limestone &om
the site and replaced CKD within the exhausted quarries. CKD is identifiable at three locations at the sUe. The
CKD sites include two exhausted quarries located on the western side of LCNC (near the Quarry Lake) and one
area of surfiCial deposit along the eastern boundary of the site, referred to as the "Badlands" (F"~ 10).
As with the Lehigh site, the primary concerns in the LCNC area include elevated pH and TDS levels. Based
on the assumed thicknesses and lateral dimensions, there are approximately 30,000 cubic yards of CKD at Quarry
pond, approximately 400,000 cubic yards in the Badlands area, and 9,000 cubic yards in the exhausted quarry.
Elevated pH levels were detected in Quarry pond (9.5) and monitoring well 14 (10.4). The water quality in
Quarry pond has deteriorated slightly, bUt the water quality in this pond was better than the water quality in the
Lehigh ponds. Arsenic was detected in two of the monitoring wells on one occasion, at 0.01 and 0.07 mgjL (well
12, well 13) and lead was above drinking water standards once, in well 14 at 0.06 mg/L Well locations are
shown in r1gW'e 11.
..
The CKD samples that were collected showed high values for extractable and final pH (11-12.7) There were
no metals parameters which tested above EP toxicity limits. This high pH was not found in the LCNC water
well, which is probably downgradient of the CKD deposits. This well is a deep well (actual depth is unknown)
and its water quality and pH are Dormal.
In summary, the specific contamination concerns at the Lime Creek site include:
L
The large volume of low toxicity CKD at the site.
2.
The presence of elevated groundwater pH readings beneath the Badlands area.
The presence of elevated pH and TDS levels in Quarry Pond.
3.
The ARARs applicable to the Plant area are applicable to Lime Creek.
28
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Fipare 9:
'" )
"-.
--
.'-.
,
'.
o
1000
2000FT
Location of Lime Creck Nature CcDtcr
/
/
29
POOR QUAUT'f
ORIGINAL
/
(
-------
o
.
500 1000FT
.
1P.
SCAL£
...
LPCC 80UNDARY
LPCC "CIL/TY .
EXPLANATION
+ KILN DUST &LE
.. MONITOR WELL
. «~~:'t~ EXPOSED KII.H DUST .
~.;;:::--'
FJprc 10:
CKD Deposits and Investigation Area
30
POOR QUALITY
ORIGINAL
i
(
-------
-
r
LPCC BOUNDARY
LPCC MCJUTY
..
..
alaD
'D
EXPLANATION
o LCNC MOHIfOfUNG WELL
Fiprc 11:
Monitoring Well LocatiODS
.
C
MW-.4S
LAKE SAMPLE
COU-ECTION LOCATION
10. .
u.
31
POOR QUALITY
ORIGINAL
-------
SUMMARY OF THE PREFERRED ALTERNATIVE
Lehigh presented similar remedial alternatives for LCNc, with the exception of an off-site landfill for LCNC and
an on-site landfill for LPCC. The Ume Creek alternatives included No Action, Consolidation and Isolation of
the CKD Deposits, Waste Stabilization, and Disposal in an Engineered Off.Site Landfill. For the same reasons
discussed in the ana1ysis for the Lehigh site, all were ruled outcxcept for Waste Consolidation and Isolation.
This alternative calls for the consolidation and capping of the area CKD deposits. By inhibiting the. interaction
of water with the CKD deposits, the quality of the area surface water and groundwater will improve through
natural dilution. Because the level of pH found at LCNC is not nearly as high as at the Lehigh site, and because
the interaction of water with CKD is the greatest concern at the site; this remedy was chosen.
The preferred alternative includes:
1. lnsta1J a dam between the two portions of Quarry Pond and drain the western pond.
NPDES discharge permit
No treatment necessary because of pond water quality
Install temporary pumping and discharge system
2. Excavate the CKD present within and around Quarry pond and transfer to the exhausted quarry cast
of Quarry pond.
3. Grade the CKD deposits in the exhausted quarry and install an engineered clay cap.
4. Consolidate the CKD in the Badlands area and cover with an engineered clay cap.
5. Allow the drained portion of Quarry pond to refill.
6. Continue groundwater and surface water monitoring.
The implementation of this alternative would result in an effective site remediation. It would accomplish this
by isolating CKD on site from both the groundwater and surface water systems. Isolation would be accomplished
by consolidation and coverage with an engineered clay cap. Capping will significantly retard the amount of water
infiltration through the CKD, and because both the exhausted quarry cast of Quarry pond and the western
portion of the Badlands are both situated weD above the water table, the introduction of high pH, high TDS
leachate into shaDow groundwater will essentially be stopped.
With significant reduction in leachate, the natural buffering systems and dilution rates will probably lower pH
and TDS concentrations to background levels. Continued monitoring will assess the effectiveness of the caps.
Overall Drotection of Human Health and the Environment and Compliance with ARARs
Through CKD isolation and gradual dilution, the area groundwater quality should cventualJy improve to
background or near background 1evels. In addition, Quarry pond will be remediated foDowing the removal of
CKD aurently in contact with the water body. Because LCNC is a public: assess area, the capping of the CKD
deposits in the area will remove it nom public: contact. An NPDES permit will be needed prior to pumping of
Quarry pond. The water pumped nom Quarry pond would not require treatment for discharge to the
Winnebago River.. With dilution, it is expected that contaminant levels of the groundwater will eventuaUy
diminish to levels below drinking water standards.
Lon2-term Effectiveness and Permanence
The isolation of the CKD from direct contact with the water systems at LCNC will result in an effec:tive and
permanent remediation. The effectiveness of the remediation will be assessed through ongoing monitoring.
32
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Reduction of Toxicitv. Mobilitv. and Volume
By isolating the CKD from interaction with surface and groundwater, the mobility of contaminants which may
migrate to the groundwater system wilJ be greatly reduced. The implementation of the alternative wilJ have no
effect on the volume of CKD, although after consolidation, its surface area wilJ be greatly reduced.
Short-term Effectiveness
The immediate beneficial short-term effect associated with this alternative wilJ be the safeguarding of the public
through CKD capping. Once initiated, the pond drainage and CKD capping process is expected to require
approximately 1.5 years to complete. Once capped, the area groundwater quality will gradually improve although
it is difficult to estimate how rapidly this wilJ be achieved.
Implementabili(y
The earth moving and pumping tedmologies are readily availabl~ i~ the Mason City area and are DOt complex..
Estimated Costs
The estimated costs associated with the implementation of the preferred alternative would be approximately
$947,000 to $1,609,000 depending on the volumes o( CKD encountered in the Quarry pond deposit and capping
requirements. The estimated present worth cost of this alternative is approximately $1.6 million.
This remedy was selected from other alternatives (similar to the ones presented (or the Lehigh site) because it
would provide protection of human health and environment, comply with ARARs, reduce the mobility and
volume o( the contaminant and have both long-term and short-term effectiveness. The preferred alternative also
has a greater assurance of effectiveness, without risk of adverse off-site impacts associated with the removal of
kiln dust to another location, and could be accomplished at a substantially lower cost. rlgW'e 12 shows the
selected remedial alternative (or the Lime Creek Nature Center.
.
33
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LPCC FACJUTY
o
.
SCALE
500 1000FT
I .
.....
LPCC BOUNDARY
'D
~
I
I
r---t
80
II
~
88m
Fipre 11:
Selected Remedial Alternative
34
POOR Q' 'A' :7'1
ORIGiML
-------
2.9 .
Statutory Detenninations
Under its legal authorities, EP A's primary responsibility at Superfund sites is to undertake remedial
actions that achieve adequate protection of human health and the environment. In addition, section 121
of CERClA established several other statutory requirements and preferences. . These specify ~ when
complete, the selected remedial action for this site must comply with applicable or relevant and
appropriate (ARARs) 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
maximum extent practical. FmaJly, 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 disc:uss how the selected remedy meets these statutory
requirements.
Protectloo or HUmaD Health aDd the Eariroament
The selected remedy protects human health and the environment by removing and treating impacted
waters and minimizing further impacts on water from the kiln dust by minimizing kiln dust contact with
water. This should result in groundwater contaminant levels below health-based standards and surface
water meeting state water quality standards. This will be aa:omplished through capping the waste kiln
dust, pond drainage, and shallow groundwater dewatering. .
F...;~ing impacted shallow groundwater will be extracted and treated by the sump used to drain the site
ponds. This will prevent off-site migration of impacted groundwater thus eliminating potential human
exposure via drinking water wells. AU water discharged to Calmus Creek or the W'mnebago River from
the site will be treated as necessary to meet Iowa water quality standards which are established to
protect aquatic life and secondary human contact (e.g. wading).
Capping of the kiln dust will reduce production of leachate due to inflltration of precipitation.
ComplJaDce with AppUcable or Relevut aad Appropriate Requlremeots
The following ARARs apply to the selected remedy. It should be Doted that levels of metals detected
in groundwater are generally low and OJ aU likelihood will Dot be a determining factor. The primary
water quality parameter of CODcern is pH.
NPDES limits, which will need to be obtained from Iowa DNR
Jowa Water Quality Standards, Chapter 61, Oass B instrcam standards (which apply to either the
W'mnebago River or Calmus Creek): .
pH
TDS
6.5 to 9.0 (the maximum change in pH sba11 not be greater than 0.5 pH units)
750 mg/l
Iowa Groundwater Action Levels. Chapter 133:
Arsenic: 0.00003 mg!L
Lead 0.015 mg!l
Chromium (total) 0.1 mg/l
35
-------
2.10
Maximum Contaminant Levels, Federal Safe Drinking Water Act (SDWA):
Arsenic 0.05 mgfl .
Lead 0.05 mgfl
Chromium(total) 0.05 mgfl
pH 6.5 to 8.5 (SecoDdary Maximum CoDtaminant Level)
State landfill requiremeDts will also apply, Chapters 100-U1.
The selected remedy sbowd be able to attam these ARARs.
Cost4ec:tfmleSs
The selected remedy is cost-effective because it is the least expensive action alternative and yet provides
a high degree of overall protection. The Other alternatives which were Icss costly did not provide long-
term remediation or compliance with ARARs. It was also uncertain whether the Waste StabillzatioD
alternative, which would be much more costly ($253 millioD dollars), could be effectively implemeDted.
The OD-Site Landfill alternative was also more costly ($19 millioD dollars) and involved the transfer of
contaminants, which couJd resuJt in other problems as well as require more maintenance. The selected
remedy will meet all ARARs and provide a long-term solution to the problem at a substantially lower
cost. Thus there arc no significant advantages to the more expensive alternatives.
Utilization of PtnDanent Solutions aad Alternative Treatment (or Resource Recovery) Technologies
10 tbe Maximum Extent PractIcable (MEP):
The Iowa DNR and EPA have determined that the selected remedy represents the maximum extent to
which permanent solutioDS and treatment technologies can be practically utilized in a cost-effective
manner for the fmal response actioDS at the LPCC site. Of those alternatives that are protective of
human health and the environment and comply with ARARs, the State and EPA have determined that
this selected remedy provides the best balance of tradeoffs in terms of long-term effectivencss and
permanence; reduction in toxicity, mobility, or volume achieved through treatment; short-term
effectivencss; implementability; cost; consideration of the statutory preference for treatment as a
principal clement; and State and community acc:cptancc.
Prelerence lor Treatment as 8 PrtndpaJ ElemeDt
Cement ki1n dust is Dot a hazardous substancc in itself. It is through interaction with water that high
pH conditions are created. The selected remedy docs not treat the ki1n dust, but it docs isolate the ki1n
dust from water to minimi7~ further production of high pH water. Existing impacted water will be
treated prior to discharge. Therefore, the statutory preferencc for remedies that employ treatment as
a principal e1emCD1 is utir:fV.4
Documentation of Sipificant Ch8DileS
The Proposed Plan for the Lehigh site was released for public comment May 20, 1991. The Proposed
PIaD identified Remedial Action Alternative 3, Waste Isolation and Capping, as the preferred alternative.
The Iowa DNR 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.
36
/
(
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APPENDIX
Groundwater and Surface Water Sampling Results
37
.
-------
Well History Information, NET and UHL Results
"" 2-S*
Indicator
Chemical
Sulfate
. Arsenic ...:
Lead
. Chromi-(
.: um,tota1).
Calcium
. .
:::tas~t~;.
Sodium
Iron,
total
.. ..
96
120()..
. . .
.. .' ..
. . ,.' .. ...
.. 0: 03\:=::.
0.12
0.01
0.02...
5.9
3100,'.
. .
-------
Well History lnformatlOD, NET ud UHL Results
MW 2-0-
bullcator
Chemical
NET
6/20/90
UHL
6/20/90
NET
7/20/90
UHL
7/20/90
NET
10/9/90
NET
11/29/90
pH 7.6 7.7 8.0 7.6
TDS 1400 - -,:-:,- 1500 - 1500 1600
Sulfate 510 550 610 S60
- Annie 0.003 <0.01- -<0.01 - <0.005 <0.010
Lad 0.001 <0.001 <0.01 <0.005 <0.010
--
- CIaromIum, <0.005 - <0.02 - -<0.02 <0.005 <0.010 -
total - ---
Calcium 110 SS 96 120 70 88
Potassium 370 300 330 - 350 490 470H --
Sodium 100 87 110 90 120 110
IrOD, total 0.29 0.22 0.36 <0.10 0.10
.AIJ values, except for pH, are Ia m&/L
39
-------
Well History Information, NET Results
MW 3-S.
Indicator NET NET NET NET
Chemical 6/20/90 7/20/90 10/9/90 11/29/90
pH 9.8 10.3/11.18 10.5 10.8
'TDS' 2100 '.'. 6300 4500.' 6000.. "
S1!~rate 320 970 800 1200
',Arsenic ."'..,., """"'" '.":";':>':""""'''.';.:,. ,\',,". '.' .:,: 0.100":: ... 0.030 "i."} ..' .
0.025 ',.,""". "/." '.'. ... '. "Y"\""""... ..,", ..
Lead 0.001 <0.005 <0.010
: Chromium, 0.006 <0.005 <0.010 '.
total ..
Calcium 230 120 1.9 1.2
. Potassium ' 500 2000 2200 2900 '
Sodium 60 180 220 240
Iron, .tota] 7.12 0.57 <0.10
. . . .
.,
. All values, except Cor pH, are in mg/L
40
-------
Well History Information, NET Results
MW 4-S.
Indicator NET NET NET NET
Chemical 6/20/90 7/20/90 10/9/90 11/28/90
pH 7.7 7.7/7.93 8.1 7.6
'ms 1100 ,.. 1300,' 1400 1300" " "
"
Sulfate 380 470 510 510
::, Arsenic 0.001'\\;::" ' : :":' '..,: :'. ,,::,:::,:::::-:""::,,' :,' <0.005 ::' " :<0.010:\ ::,:;:::
,:,:',:'''..' ,':
Lead 0.001 <0.005 <0.010
Chromium, , 0.042 '" '" <0.005 <0.010 "
total ' '::::=
Calcium 1300 190 41 77
Potassium 210 280 510 400. "
"
Sodium 64 84 91 100
Iron, total 24.7 1.8 0.83 0.38 ' ,
. All values, except for pH, are in mg/L
41
-------
Well Histol")' Information, NET and UHL Results
MW 5-8-
ladlcator NET UHL NET UHL NET NET
Cbemlcal 6/20/90 6/10/90 7/10/90 7/20/90 10/9/90 11/29/90
pH 10.4 10.65 10.2 10.67 10.2 10.6
-TDS - 3200 2300. 2300 4100
Sulfate S80 S40 S80 860
Anealc 0.028. 0,07 O.G4 0.080 0.0290
Lead 0.001 0.52 <0.01 <0.005 <0.010
..
- CIaromJum. - 0.009 -.. .0.04-.- <0.02 .. . <0.005 -- <0.010 --
tota1
Calcium 1100 2400 520 1600 14 23
Potassium 900 1000 1200 980 1000 1700
Sodium 130 140 120 120 130 220
Iron, total 19.1 72 12 28 1.4 2.2
- All values. except for pH. 8ft In mg/L
42
/
(
-------
Indicator
Chemical
pH
'TOS
Sulfate
.......',
;:ArSenlc ..'. .,. .
Lead
. Chromium,
. total
Calcium
Potassium
Sodium
. Iron, tota]
Well History Information, NET Results
MW 6-D*
. .
..
NET
6/20/90
7.6
1400 ...
570
0.002": ...
OJ)()3
0.04
NET
7/20/90
7.2
700
140
NET
10/9/90
7.9
1600
860
1700
180
51
55.8
... ..".:..,.. .... ....< .
-------
Well Histol)' Infonnation, NET Results
MW 7.S.
Indicator NET NET NET NET
Chemical 6/20/90 7/20/90 10/9/90 11/28/90
pH 72/6.80 72/7.45 73 7.0
..ms.. 760. 700 ..H/ ... 620 800.
Sulfate 130 140 130 200
:.AlWnic. .. .....
0.004. .":':".:'.. .,:";"'.....,.....:... <0.005 <0.010
Lead 0.001 <0.005 <0.010
. Chromium, 0.038 0.035:. . .. <0.005 <0.010
.. ..
.total ..
Calcium 160 180 120 170
Potassium 23 26 15 18
Sodium 16 22 20 23
Iron, total 37.5 51 4.6 0.23
. All values, except for pH, are in mg/L
44
-------
Well History Infonnation, NET and UHL Results
MW S.D.
Indicator UHL NET NET
Chemical 6/20/90 10/9/90 11/29/90
pH 9.85 9.7/9.75 9.5
:ms. 3700: . 4100....
Sulfate 1200 1100
: Arsenic 0.040:: ~O.010 .:. :'.:
Lead <0.005 <0.010
. Chromium, <0.005
total ".." ..
Calcium 250 150 110 5.6 6.4
Potassium 1200 1600 1700 1700 1600
Sodium 190 140 200 210 210
Iron, totaJ. 15.0 26 0.76 0.50
. All values, except for pH, are in mg/L
4S
-------
Well History larormatlOD, NET and UHL Results
MW 9-8*
.
ladicator NET NET UHL NET UHL NET
Chemical 6/1.0/90 7/1.0/90 7/1.0/90 10/9/90 10/9/90 11/1.9/90
pH 10.8 10.8 11.43 11.2 lLO
:TDS 7000 9700 . 6300:.. 6800
Sulfate 1300 1500 1400 1400
. AneDlc. 0.038 .::.... O.OS. 0.070 0.02 0.021
Lead 0.010 <0.01 0.033 <0.01 <0.010
: Chromium... <0.005 .. <0.02 <0.005 . <0.02 . <0.010
total '
.
Caldum 63 46 79 054 30 1.7
.. Potassium 2200 2tiOO 3000 3200 3000 3000 .
SodJum 240 270 280 280 260 140 .
1roD. total. 258 3.2 <0.15 1.3 0.12 ..
..
* All values. aeept ror pH. are fa mg/L
46
-------
Surface Water SampllDg History, NET ud UHL Results
Blue Waters PODd-
Indicator NET UHL NET UHL NET UHL NET
Chemical 6/1.0/90 6/1.0/90 7/1.0/90 7/1.0/90 10/9/90 10/9/90 11/28/90
pH 10.8 11.54 10.7 12.08 10.6 11.2 11.0
7300 7600 ... .. . ...
1'OS. 6100.. . 6SOO .'.....
Sulfate 1300 1200 1400 1300
.. AneDk 0.039 0.06 . 0.03 . 0.100 .::. .<0.01. 0.031
Lead 0.004 <0.001 <0.01 0.006 < 0.01 <0.010
<0.()2 ...,..,..:. <.. ..., ..,..,..... .. .
Cbromi. . <0.005 . .>/ <0.02' . .
-------
Surface Water Sampling Hlstol')'., NET aod UHL Results
Area .C' Pond-
c
IDdic:ator NET UIIL NET NET NET
Cbemlcal 6/1.0/90 6/1.0/90 7/1.0/90 10/9/90 11/1.8/90
pH 11.2 11.73 10.8/12.05 11.0/11.4 11.0
.,:ms 7200 8900 6200 6800
Sulfate 1300 1400 1400 1400
,ArseDlc 0.040 0.06 0.120 0.033"
Lad 0.006 <0.001 0.006 <0.010
.." .. ':'i': ,:"",,:':
::'Cbromlum,
-------
Surface Water Sampling History, ,NET Results
Arc:b PODd-
ladicator NET NET NET NET
Chemical 6/10/90 7/10/90 10/9/90 11/18/90
pH 12.3/13.0 12.3/13.15 12.0/13.1 11.3/11.38
,',' ',,' '
nTDS, ', 11000 l(xx)o , 2SOOO 6SOO "" n
Sulfate 2000 1800 4700 1500
. Anaalc " 0.040' O.OSO "":"": ni 0.200 '.' 0.023.",.
" .'::' ,'., ,
Lead 0.002 0.029 <0.005 <0.010
<0.005 ' :':". .,,", ',: «tOl0::\:'\: , '
Chromium, total <0.10 n:,:' n( ,n, , O.OO6n n
Caldum 1.5 12.0 0.07 8.6
Potassium 3800 S4.0' 11000 2800' " n
Sodium 270 400 830 280
Iron, total 0.23 032 0.12' 0.11
- All values, except for pH, are In mgfL
49
.
-------
Well History Information, NET ad UIIL Results
MW lo.s.
.
ladiaator NET UHL NET UHL
Chemlaal 10/9/90 10/9/90 11/29/90 12/11/90
pH 9.0 9.1 9.0 8.53
TDS 1800 1700
Sulfate 530 440
ArseDIc: 0.040 <0.01 .....' . <0.010
-------
WeD History Information. NET aad um.. Results
MW 1105.
IndJcator NET VHL NET um..
Chemical 10/9/90 10/9/90 11/1.9/90 U/l1/90
pH 7.4 6.7 7.3 6.88
. TDS 670 . . >. ..:.:;.:.'.,:.:::.'. .: .:.:. 730:.... . ..
Sulfate 180 160
.. <0.005... .,... ,.'.:'.:..:',: ." <0.010 ::.
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