EPA Superfund
Record of Decision:
PB95-964301
EPA/ROD/R07-95/075
February 1995
Quality Plating Site,
Sikeston, MO
1/24/1995
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RECORD OF DECISION
QUALITY PLATING SITE
SIKESTON, MISSOURI
PREPARED BY:
UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
REGION VII
KANSAS CITY, KANSAS
JANUARY 1995
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DECLARATION FOR THE RECORD OF DECISION
SITE NAME AND LOCATION
Quality Plating Site
Sikeston, Missouri
STATEMENT OF BASIS AND PURPOSE
This decision document presents die selected remedial action for die Quality Plating site north of
Sikeston, Missouri chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA), as amended by the Superfund
Amendments and Reauthorization Act of 1986 (SARA) and the National Contingency Plan, 40
C.F.R. Part 300. This decision is based on the Administrative Record file for die site.
The State of Missouri concurs on the selected remedy. A letter from die State of Missouri stating
it's concurrence is included in this Record of Decision (ROD) package.
ASSESSMENT OF THE SITE
Actual or threatened releases of hazardous substances from the Quality Plating Site, if not
addressed by implementing the response action selected in this ROD, may present an imminent
and substantial endangerment to public health, welfare, or the environment.
DESCRIPTION OF THE SELECTED REMEDY
The selected remedy is extraction of contaminated groundwater through two extraction wells,
treatment of the contaminated groundwater by reduction/precipitation, and discharge of the
treated groundwater to Ditch Number 4 approximately 4,000 feet east of die site. The discharge
will be under die authority of a state operating permit. Discussion widi Scott County Road
personnel have indicated the routing of the discharge pipe along Scott County Road 448 will be
acceptable.
Two primary treatment processes could be used to reduce the hexavalent chromium to a less toxic
form, trivalent chromium; chemical reduction or electrochemical reduction. During the remedial
design tests will be completed to determine which process is more appropriate for this specific
site.
If die chemical reduction system is chosen, the extracted groundwater will be pumped from die
extraction wells system to the influent holding tank for flow equalization. Groundwater will then
be discharged to the chemical reduction tank where sulfuric acid will be added to reduce the pH
alkalinity of the groundwater. With the addition of a chemical, such as ferrous sulfate, the
treatment system will then reduce die hexavalent chromium to the less toxic trivalent chromium.
Trivalent chromium will be precipitated out of solution as chromium hydroxide and pumped to a
sludge holding tank where die sludge will be dewatered using a filter press, characterized for
hazardous levels of metal contamination, and then sent off-site for proper disposal. The
MDNR's Water Pollution Control Program has indicated the treated groundwater discharge to
Ditch Number 4 will be limited to 0.28 mg/1 total chromium. It is anticipated that chemical
reduction will remove approximately 90% of the total chromium from the groundwater being
treated. This process will be expected to provide a treated discharge significandy lower than the
0.28 mg/1 total chromium effluent limit.
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The extraction wells will be constructed of 6-inch PVC pipe to a total depth of 35 feet below
ground surface (bgs) and be screened for a 20 foot interval. A pumping rate of 75 gallons per
minute (gpm) for each well or a total flow rate of 150 gpm will be used to contain the plume.
Institutional controls (a groundwater monitoring program) will be implemented to monitor the
plume and remediation process. A groundwater monitoring plan will be necessary.
STATUTORY DETERMINATIONS
The selected remedy for the Quality Plating Site is protective of human health and the
environment, complies with Federal and State requirements chat are legally applicable or relevant
and appropriate to the action for the Site, and is cost-effective. This action constitutes the final
remedy for the site, and the statutory preference for remedies that employ treatment that reduces
toxicity, mobility, or volume as a principal element, is met by this remedy.
This remedy will not result in hazardous substances remaining on the site above health-based
levels. A review will be conducted to ensure that the interim action for Quality Plating Site
continues to provide adequate protection of human health and the environment within five years
after commencement of th? interim action.
Dennis Grams, P.ez' Date
Regional Administrator
U.S. EPA, Region VII
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TABLE OF CONTENTS
Declaration of the Record of Decision
Decision Summary
Section Page
1.0 SITE NAME, LOCATION, AND DESCRIPTION 1
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES 4
3.0 PUBLIC RELATIONS ACTIVITIES 5
4.0 SCOPE AND ROLE OF RESPONSE ACTION 5
5.0 SUMMARY OF SITE CHARACTERISTICS 17
6.0 SUMMARY OF SITE RISKS 21
7.0 REMEDIAL ACTION OBJECTIVES 29
8.0 DESCRIPTION OF ALTERNATIVES 29
9.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES 40
10.0 SELECTED REMEDY 43
11.0 STATUTORY DETERMINATION 44
12.0 DOCUMENTATION OF SIGNIFICANT CHANGES 46
RESPONSIVENESS SUMMARY
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LIST OF FIGURES
1. State Location Map
2. Area Location Map
3. Horizontal Extent of Contamination
4. Cross Section of Contamination
5. Conceptual Model of Exposure Pathways
6. Location of Discharge to Ditch No. 4 and POTW
7. Containment Extraction Well Location
8. Active Restoration Extraction Well Location
LIST OF TABLES
1. Summary of Groundwater Well Samples
2. Summary of Well Screen Groundwater Well Samples
3. Summary of Absorbed Toxicity Values
4. Hazard Index Values For Adult
5. Hazard Index Values For Child
6. Summary of Non-carcinogenic Risks
7. Groundwater Preliminary Remediation Goals
8. Groundwater Alternatives
9. Cost Sensitivity Analysis
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1
RECORD OF DECISION
DECISION SUMMARY
1.0 SITE NAME, LOCATION, AND DESCRIPTION
1.1 SITE NAME AND LOCATION
The Quality Plating site is on Scott County Highway 448, north of Sikeston, Missouri, in Scott
County. The site occupies portions of the NW 1/4, NW 1/4, Section 28, and portions of the
NE 1/4, NE 1/4, Section 29, Township 27 North, Range 14 East. This site is approximately 5
acres and previously consisted of the manufacturing plant, a one-acre lagoon, and a sludge pit.
The foundation of the manufacturing plant remains on-site with the wastewater lagoon, however
the sludge pit has been removed and the excavation backfilled with native soil. The location of
the site is found on Figures 1 and 2.
1.2 TOPOGRAPHY
The topography of the area is characterized by a slightly rolling landscape to the north and west
and relatively flat terrain in the soudieasterly direction. The site is on the northern portion of the
Sikeston Ridge, a relatively flat terrace averaging about 20 feet higher in elevation that die
adjacent lowlands to the north, east, and west. The elevation in the immediate area is
approximately 325 feet above sea level with local relief being approximately 20 feet. Surface
drainage from the site is to the east to a tributary of St. John's Ditch.
The Quality Plating site is located in the Mississippi Embayment of the Gulf Costal Plain
physiographic province. Geologically, the Mississippi Embayment is a syncline which plunges to
the south and whose axis generally parallels the Mississippi River. Locally, the terrace on which
the site is located is an alluvial landform produced by alternate aggradation and degradation of
die Ohio and Mississippi Rivers. The sandy surface of the terrace is covered by a closely spaced
network of braided stream channels. The interbraids are peppered with hollowed mounds of
sand which are referred to as blowouts. One of diese blowout features is located on the site and
was used as the wastewater lagoon. The soil survey from Scott County, Missouri identifies the
soil at the site as belonging to the Scotco series. This series consists of deep, excessively drained,
rapidly permeable soils.
The site is underlain by approximately 200 feet of alluvium consisting of sand and gravel. Area
well logs show only minor clay or silt present in the upper five feet of alluvium. The alluvium is
recharged by precipitation and to lesser degree by streams, drainage ditches, and rivers during
high stages. Discharge from the alluvium is by natural drainage into a few streams in the
Sikeston Ridge area, the Mississippi River, manmade drainage ditches,
evapo-transpiration, and groundwater usage. Underlying the alluvium is the Porters Creek
Formation which consists of about 35 feet of uniform, dark clay.
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RGURE 1
SITE VICINITY MAP
QUALITY PLATING SITE
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s ; A .____Y^ zw
' DITCH NO. 4 -
i1 u. -4^e
QUALITY PLATING SITE
W; ^IW.
I \ _ . , / \J i i - f
\H L A! '}
FIGURE 2
SITE LOCATION MAF
QUALITY PLATING SITE
FEASIBILITY STUDY
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1.3 ADJACENT LAND USES
There are six residences located within 1/4 mile from the site and all have private wells for a
drinking water source. The surrounding land is used primarily for agricultural purposes (row
crops). From time to time, the existing landowner raises calves on the site, and an adjacent
landowner raises horses.
2.0 SITE HISTORY AND ENFORCEMENT ACTIVITIES
2.1 SITE HISTORY
Quality Plating was engaged in contract plating of common and precious metals, which included
cadmium, chromium (hexavalent form), copper, nickel, and zinc from 1978 until the facility was
destroyed by fire on February 12, 1983. Untreated wastewater originating from the rinse tanks
and metal plating batch solutions was continuously discharged into an on-site unlined lagoon at a
rate of approximately 10,000 gpd. Wastewater discharged to the lagoon then rapidly percolated
through the sandy soil and infiltrated into the groundwater ("subsurface water of the state").
Sludge, generated during plant operations, was buried in the sludge pit in the southwestern
portion of the site.
A Phase I Remedial Investigation (RI) was conducted at the Quality Plating site between
December 1991 and February 1992. Results of the RI identified significantly elevated levels of
heavy metals in the soils and sludge pit area and on-site levels of total chromium, iron, and
manganese, which exceeded the water quality standards current at the time, in the shallow
groundwater. These levels were confirmed by the Environmental Protection Agency (EPA) in a
Removal Assessment conducted in February 1992.
EPA recommended a time-critical removal action be implemented at the site, to address the
immediate health threats posed by the contents of the sludge pit and that the site be included as
part of a Superfund Accelerated Cleanup Model (SACM) pilot program currently being
implemented in EPA Region VII. An Action Memorandum was prepared and a soil removal
action at the site was implemented by EPA.
Approximately 900 cubic yards of contaminated sludge pit waste were excavated and transported
off-site to a Resource Conversation and Recovery Act (RCRA) approved facility for final
treatment and disposal. Confirmation sampling and analysis was conducted and verified that soil
cleanup levels had been achieved. The following soil cleanup levels were identified in the Action
Memorandum signed by EPA in August 1992: Total Chromium, 2,000 milligrams per Kilogram
(mg/Kg); Chromium, 180 mg/Kg; Nickel, 1,100 mg/Kg; and Zinc, 5,600 mg/Kg.
A Further Investigation of Groundwater (FIG) Report was completed in October 1993. It was
the recommendation of the FIG that remediation of the groundwater at the Quality Plating site is
warranted and that a Feasibility Study (FS) be performed for the purposed of identifying the
most cost-effective and appropriate remediation activities at the site. This recommendation was
based on the existence of contaminated groundwater at the site which exceeded site-designated
risk-levels and the existence of known shallow groundwater down gradient of the site. The FS
was completed in June 1994.
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2.2 ENFORCEMENT HISTORY
The MDNR's Southeast Regional Office wrote three Notice Of Violations (NOVs) to Quality
Plating between December 8, 1981 and September 20, 1982 for discharging untreated
electroplating wastewater without an NPDES permit. On December 17, 1982 an Abatement
Order to cease the discharge was issued.
3.0 PUBLIC RELATIONS ACTIVITIES
An availability session was held on October 30, 1991 in which information was exchanged
between area residents and MDNR personnel. Additional meetings were held on August 11 and
December 8, 1992 and questions of the area residents were answered on such topics as health
aspects associated with the site, private drinking water testing, and CERCLA enforcement
requirements. On September 30, 1993 a public meeting was held to present the findings
contained in the FIG Report.
The FS and Proposed Plan, which were included as part of die Administrative Record (AR), were
made available to the public at the Sikeston Public Library and at the offices of EPA in Kansas
City, Kansas and at the MDNR in Jefferson City, Missouri. The notice of availability for the AR
and the announcement of a public meeting held on October 3, 1994 was published in the
Sikeston Standard Democrat on September 11, September 28, and October 2, 1994. The public
comment period was held from September 11, 1994 to October 11, 1994. On October 9, 1994
the public comment period was extended an additional 30 days to November 10, 1994. At this
meeting, representatives from the MDNR and EPA received public comments and answered
questions about problems at the site and the remedial alternatives under consideration. A
response to the comments received during this period is included in the Responsiveness Summary,
which is part of this Record of Decision (ROD).
This decision document presents the selected remedial action for the Quality Plating site in
Sikeston, Missouri, chosen in accordance with the Comprehensive Environmental Response,
Compensation, and Liability (CERCLA) Law of 1980, as amended by the Superfund
Amendments and Reauthorization Act (SARA) of 1986, and to the extent practicable, the
National Contingency Plan (NCP). This decision is based on the Administrative Record for this
site.
4.0 SCOPE AND ROLE OF RESPONSE ACTION
The response action selected in this ROD will address the contamination at the site not addressed
during the prior removal action. This response action involves removal and treatment of
hexavalent chromium contaminated groundwater.
The remedial action selected in this ROD is intended to address the entire site with regard to the
principal threats to human health and the environment posed by contamination at the site as
indicated in the risk assessment for the site. The findings of the risk assessment are included in
the Administrative Record and are summarized in Section 6.0 of this document.
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Table 1
Summary of Groundwaler Well Sample Results
Quality Plating Site
Fcasbitity Study
Sample ID
Date Collected
Toj^l Alkalinity
Bicarbonate Alkalinity
Carbonate Alkalinity
Hydroxide Alkalinity
Total Dissolved Solids
Turbidity
Hexavalenl Chromium
Total Chromium
Iron
Lead
Manganese
Nickel
Zinc
Units
mg/L
mg/L
rng/L
mg/L
mg/L
NTU
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
MCL(aySMCL(b)
--
--
--
500.0 (b)
--
100.0 (a)
300.0 (b)
15.0 (a)
50.0 (b)
100.0 (a)
5000.0 (b)
Preliminary
Remediation Goal (c)
--
--
--
--
18.0
3500.0
__
__
18.0
70.0
1000.0
QP-93-MW-1
03/18/93
20.0 U
20.0 U
0.0
0.0
120.0
< 1.0
10.00 U
10.0 U
126.0
3.0 U
15.0 U
40.0 U
20.0 U
QP-93-MW-2
03/18/93
20.0 U
20.0 U
0.0
0.0
90.0
< 1.0
:-.>:;-. .': :.' i 28.00 . : !
38.0
102.0
3.0 U
15.0 U
40.0 U
20.0 U
QP-93-MW-2-MS/MSD
(Duplicate, See Note d)
03/18/93
NA
NA
NA
NA
NA
NA
..- .V,; .:.;<., .76JOO :';':.
39.0
245.0
3.0 U
15.0 U
t 40.0 U
20.0 U
QP-93-MW-2-(2)
03/20/93
NA
NA
NA
NA
NA
NA
.;:;-: ;::; ;-;.-v.. 39.00 :-. .'
NA
NA
NA
NA
NA
NA
NA - Not Analyzed Value exceeds either the MCL/SMCL or PRO.
NTU - Nephelometric Turbidity Units
U - Undetected
(a) Maximum Contaminant Level. Maximum permissble level as established by the Safe Drinking Water Act (40 CFR 141)
fora contaminant in water that is delivered to any user of a public water system. (Lead value is defined as an 'action level* rather than an MCL)
(b) Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water that primarily affect the aesthetic qualities (40 CFR 143).
(c) Preliminary Remediation Goals as determined by MDOH.
(d) Sample QP-93-MW -2 -MS/MSD was designated by BVWST as a mat TO spike sample; however, the laboratory incorrectly analyzed the sample as a duplicate.
No other samples were analyzed as MS/MSD samples for the groundwalcr wells.
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Table 1- ' (Continued)
Summary of Groundwaler Well Sample Results
Quality Plating Site
Feasfcility Study
Sample ID
Dale Collected
Tola) Alkalinity
Bicarbonate Alkalinity
Carbonate Alkalinity
Hydroxide Alkalinity
Total Dissolved Solids
Turbidity
Hexavalenl Chromium
Total Chromium
Iron
Lead
Manganese
Nickel
Zinc
Units
ms/L
mg/L
mg/L
mg/L
mR/L
NTU
ug/L
UR/L
UR/L
UR/L
ug/L
ug/L
UR/L
MCL(aySMCL(b)
--
--
--
--
500.0 (b)
--
100.0 (a)
300.0 (bl
15.0 (a)
50.0 (b)
100.0 (a)
5000.0 (b)
Preliminary
Remediation Goal (c)
--
--
--
~-
--
18.0
3500.0
--
__
18.0
70.0
1000.0
QP-93-MW-3
03/18/93
36.0
36.0
0.0
0.0
120.0
< 1.0
" .-:: = :.:-:""-«.W-W"'::
72.0
100.0 U
3.0 U
15.0 U
40.0 U
20.0 U
QP-93-MW-3-(D)
03/18/93
NA
NA
NA
NA
NA
NA
:*;!;:;:₯-«'- 45.00 ;::?.,:
75.0
136.0
3.0 U
15.0 U
40.0 U
20.0 U
QP-93-MW-3-(2)
03/20/93
NA
NA
NA
NA
NA
NA
: :«:: : . .J^X .^ SgS;- .'.71 .00 ₯ : K :-:,'.
NA
NA
NA
> NA
NA
NA
QP-93-MW-4
03/17/93
20.C
20.C
0.0
0.0
100.0
< 1.0
10.00
10.0
129.0
3.0
V4:.:«WS:>*fe24.0.-
40.0
20.0
NA - Not Analyzed
NTU - NcphelomelricTurbidity Units
U - Undetected
: Value exceeds either ihcMCL/SMCL or PRO.
(a) Maximum Contaminant Level. Maximum permissible level as established by the Safe Drinking Water Act (40 CFR 141)
for a contaminant in water that is delivered to any user of a public water system. (Lead value is defined as an "action level" rather than an MCL.)
(b) Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water that primarily affect the aesthetic qualities (40 CFR 143).
(c) Preliminary Remediation Goals as determined by MDOH.
(d) Sample QP-93-MW-2-MS/MSD was designated by BVWST as a matrix spike sample; however, the laboratory incorrectly analyzed the sample as a duplicate.
No other samples were analyzed as MS/MSD samples for the groundwaler wells.
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Table 1 (Continued)
Summary of Groundwater Well Sample Results
Quality Plating Site
Feasibility Study
Sample ID
Dale Collected
total Alkalinity
Bicarbonate Alkalinity
Oxilbnate Alkalinity
Hydroxide Alkalinity
Total Dissolved Solids
Turbidity
Hexavalent Chromium
Total Chromium
Iron
Lead
Manganese
Nickel
Zinc
Units
mg/L
mg/L
mg/L
mg/L
mg/L
NTU
ug/L
UR/L
UR/L
UR/L
UR/L
"E/L
UR/L
MCL(aySMCL(bj
--
--
--
500.0 fb)
100.0 (a)
300.0 (b)
15.0 (a)
50.0 (b)
100.0 (a)
5000.0 (b)
Preliminary
Remediation Coal(c)
--
--
18.0
3500.0
--
__
18.0
70.0
1000.0
QP-93-WH-1
03/17/93
20.0 U
20.0 U
0.0
0.0
120.0
< 1.0
10.00 U
10.0 U
100.0 U
3.0 U
15.0 U
40.0 U
30.0
QP-93-IGN
03/20/93
57.0
57.0
0.0
0.0
80.0
< 1.0
10.00 U
10.0 U
K:-^f-yff^-^--V:43ljO::^i^
3.0 U
.,;:«: :, ;4
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oU.
Tablet- (Continued)
Summary of Groundwatcr Well Sample Results
Quality Plating Site
Feasbilily Study
Sample ID
Date Collected
Total Alkalinity
Bicarbonate Alkalinity
Carbonate Alkalinity
Hydroxide Alkalinity
Total Dissolved Solids
Turbidity
Hexavalenl Chromium
Total Chromium
Iron
Lead
Manganese
Nickel
Zinc
Units
nifi/L
mg/L
mR/L
niK/L
mg/L
NTU
ug/L
ug/L
ug/L
"g/L
ug/L
ug/L
ug/L
MCL(aySMCL(b)
--
--
--
500.0 (b)
100.0 M
300.0 (b)
15.0 (a)
50.0 (b)
100.0 (a)
5000.0 (b)
Preliminary
Remediation Coal (c)
--
'
--
--
--
--
18.0
3500.0
--
--
18.0
70.0
1000.0
QP-93-MW-3-(2)-(R)
03/20/93
NA
NA
NA
NA
NA
NA
10.00 U
NA
NA
NA
NA
NA
NA
NA - Not Analyzed Value exceeds either the MCL/SMCL or PRO.
NTU - Nephelometric Turbidity Units
U - Undetected
(a) Maximum Contaminant Level. Maximum permissive level as eslablishedby the Safe Drinking Water Act (40 CFR 141)
fora contaminant in water that is delivered to any user of a public water system. (Lead value is defined as an "action level"
rather than an MCL)
(b) Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water that primarily affect the aesthetic
qualities (40 CFR 143).
(c) Preliminary Remediation Goals as determined by MDOII.
(d) Sample QP-93-MW-2-MS/MSD was designated by BVWST as a matrix spike sample; however, the laboratory incorrectly
analyzed the sample as a duplicate. No other samples were analyzed as MS/MSD samples for the groundwater wells.
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ok.
TABLE 2
Summary ol Puib-In Well Screen Groundwalcr Samples
.Quality Pilling
Feasibility Study
Simple ID
Due (Collected
Ton) Alkalinity
Bicirbooale Alkalinity
Carbonate Alkalinity
Hydroxide Alkalinity
Total Dissolved Solids
Turbidity
Hexavalenl Chromium
Total Chromium
Iron
Lead
Manganue
Nickel
Zinc
Units
mg/L
mg/L
mg/L
mg/L
mx/L
NTU
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
MCL(a)/SMCL(b)
500.0 (b)
100.0 (a)
300.0 (b)
15.0 (a)
50.0 (b)
100.0 (a)
5000.0 (b)
Preliminary
Remediation Coals (c)
--
--
--
--
18.0
3500.0
--
--
18.0
70.0
1000.0
QP-93-03-24-HP-R
03/24/93
20.0 U
20.0 U
0.0
0.0
1.0 U
< 1.0
10.00 U
10.0 U
100.0 U
3.0 U
15.0 U
40.0 U
20.0 U
QP-93-03-25-HP-R
03/25/93
NA
NA
NA
NA
NA
NA
10.00 U
10.0 U
100.0 U
3.0 u;
15.0 U
40.0 U
20.0 UJ
QP-93-03-26-HP-R
03/26793
NA
NA
NA
NA
NA
NA
10.00 U
10.0 U
100.0 U
3.0 UJ
15.0 U
40.0 U
26.0 J
NA - Not Analyzed Value exceeds either the MCL/5MCL or PRO.
NTU - Ncphelomelric Turbidity Units
U - Undetected >
3 - Estimated
(a) Maximum Contaminant Level. Maximum permissible level u established by the Safe Drinking Water Act (40 CFR 141)
fora contaminant in water thai is delivered to anyiucr of a public water system. (Lead value is defined as an 'action level" rather Ihio an MCL.)
(b) Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water Ibal primarily affecl Ibe aesthetic qualities (40 CFR 143).
(c) Preliminary Remediation Ooab u determined by MDOH.
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OIL
TABLE 2 (CONTINUED)
Summary of Push-In Well Screen Groundwater Simple*
Quality PlaliDg
Feasibility Study
Simple ID
Date Collected
Tolil Alkilinily
Bicarbonate Alkalinity
Cirbonale Alkalinity
Hydroxide Alkalinily
Tola! Dissolved Solids
Turbidity
Hexavalenl Chromium
Tola! Chromium
Iron
Lead
Manganese
Nickel
Zinc
Units
mg/L
mg/L
mj/L
mg/L
rag/L
NTU
ug/L
uj/L
ug/L
ug/L
ug/L
ug/L
ug/L
MCL(aySMCL(b)
--
--
500.0 (b)
--
100.0 (a)
300.0 (b)
15.0 {a}
50.0 jb)
100.0 (i)
5000.0 (b)
Preliminary
Remetlialion Goals (c)
.
--
--
--
18.0
3500.0
--
--
18.0
70.0
1 000.0
QP-93-HP-2(24-25)-2
03/23/93
20.0 U
20.0 U
0.0
0.0
160.0
8.0
235.00 : .
I 3.-5J.O
840.0
3.0 U
15.0 U
40.0 U
20.0 U
QP-93-HP-3(24-25)
03/2X/93
20.0 U
20.0 U
0.0
0.0
90.0
7.0
10.00 U
10.0 U
752.0 .
3.0 UJ
15.0 U
40.0 U
20.0 UJ
QP-93-HP-3 (49-50)
03/25/93
72.0
72.0
0.0
0.0
140.0
16.0
10.00 U
10.0 U
1150.0
3.0 UJ
224.0 :
40.0 U
20.0 UJ
QP-93-HP-4 (24-25
03/24/93
77.0
57.0
20.0
0.0
240.0
51.0
1201.00
1440.0
- 3710.0
3.3
27.7
40.0 I
20.0 I
NA - Not Analyzed Value exceed! either the MCL/5MCL or PRO.
MTU - Nephcloroelric Turbidity UniU
U - Undetected
J - Estimated
(a) Maxjmum Contaminant Level. Maximum permissible level u cslablbbed by the Safe Drinking Water Act (40 CFR 141)
for a contaminant in water that is delivered to any user of a public water system. (Lead value is defined as an "action leveP rather than ao MCL.)
(b) Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water Ibal primarily af/eci the jeslhclic qualities (40 CFR 143).
(c) Preliminary Remediation Goals as determined by MDOH.
-------
TABLE 2 (CONTINUED)
Summary of Hush-In Well Screen Croundwaler Sample*
Quality Plating
Feasibility Study
Sample ID ull.
Dale Collected
! Total Alkaliniry
Bicarbonate Alkalinity
|| Carbonate Alkalinity
i Hydroxide Alkalinity
H Total Dbiolved Solids
j| Turbidity
! Hexavalenl Chromium
1 Tola! Chromium
Iron
iLod
Sf anjtaoese
Nickel
! Zinc
Units
mg/L
tng/L
mg/L
mg/L
mg/L
NTU
ug/L
ug/L
ug/L
»g/L
ug/L
ug/L
ug/L
MCL(a)/SMCL(b)
--
--
--
500.0 (b)
--
--
100.0 (>)
300.0 (b)
ts.o M
50.0 (b)
100.0 (a)
5000.0 (b)
Preliminary
Remediation Goab (c)
--
--
--
--
--
18.0
3500.0
--
--
18.0
70.0
1000.0
QP-9J-HP-4 (24-2SJ-D
OJ/25/93
77.0
57.0
20.0
0.0
270.0
51.0
1206.00
1460.0
3910.0 :.
3.5 }
' : -: :-.. :-40.«
40.0 U
21.0 ]
3P-93-HP-4 (49-50)
03(75/93
124.0
124.0
0.0
0.0
220.0
9.0
10.00 U
10.0 U
777.0
3.0 UJ
: 453.0 .
40.0 U
20.0 UJ
QP-93-HP-5 (24-2SJ-2
03(72/93
20.0 U
20.0 U
0.0
0.0
110.0
< 1.0
10.00 U
10.0 U
1320.0
3.0 U
.' 21.0
40.0 U
20.0 U
QP-93-HP-S (24-25)20
03(72/93
20.0 U
20.0 U
0.0
0.0
110.0
13.0
10.00 U
10.0 U
1410.0 -
3.0 U
21.1 :.::;.-
40.0 U
20.0 O
NA - Nol Analysed Value exceeds either Ihe MCL/SMCL or PRO.
NTU - Nepbelomelric Turbidity Units
U - Undetected
1 - Estimated
(a) Maximum Contaminant Level. Maximum permissible level u established by the Safe Drinking Water Act (40 CFR 141)
for a contaminant in water thai is delivered to any user of a public water system. (Lead value is defined as an 'action level" rather than an MCL.)
1(b) Secondary Maximum Contaminant Levels. Regulate] contaminants in drinking water that primarily affect Ihe autbelicquililiei (40 CFR 143).
(c) Preliminary Remediation Coats u determined by MDOH.
-------
TABLE 2 (CONTINUED)
Summary o( Puih-ln Well Screen Groundwater Sample*
Quality Plating
Feasibility Sludy
Simple ID
Toul Alkalinity
Bicarbonate Alkalinity
Carbonate Alkalinity
Hydroxide Alkalinity
Total Dissolved Solids
Turbidity
Hexavalent Chromium
Total Chromium
Iron
Leid
Manganese
Nickel
Zinc
Units
mg/L
mg/U
tnfi/L
rog/L
rog/L
NTU
UR/L
ug/L
ug/L
ug/L
up/L
UR/L
ug/L
MCL(aySMCL(b)
--
--
500.0 (b)
__
100.0 7.0
300.0 (b)
15.0 (»)
50.0 (b)
100.0 (a)
5000.0 (b)
Preliminary
Remediation Goals (c)
__
18.0
J500.0
__
__
15.0
70.0
1000.0
QP-93-HP-5 (49-50)
03/22/93
62.0
62.0
0.0
0.0
110.0
140.0
10.00 U
11.0
15200.0
3.0 U
«42.0 :
40.0 U
20.0 U
QP-93-HP-6 (l9-20)-2
03/24/93
NA
NA
NA
NA
NA
10.00 U
NA
NA
NA
NA
L NA
NA
QP-93-HP-6(l9-20)2F
03/24/93
NA
NA
NA
NA
NA
10.00 U
NA
NA
NA
NA
NA
NA
QP -93 -HP -1(24 -25)
03/23/93
NA
NA
NA
NA
NA
10.00 U
NA
NA
NA
NA
NA
NA
HA - Not Analyzed Value exceeds either (he MCU5MCL or PRO.
NTU - Nepbelometric Turbidity Units
U - Undetected
J - Estimated >
(*) Maximum Contaminant Level. Maximum permissible level u established by the Safe Drinking Water Act (40 CFR HI)
(or a contaminant in water that is delivered to any user of a public water system. (Lead value is defined as an 'action leveP rather than an MCL.)
(b) Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water that primarily affect the aesthetic qualities (40 CFR 143).
(c) Preliminary Remediation Goals as determined by MDOH. . . '
-------
TABLE 2 (CONTINUED)
Summary of Puih-In V ;ll Screen Grouudwaler Samplei
Qualily Filling
Feasibility Study
Sample 1 D
Dale Collected
Tola! Alkalinity
Bicarbonate Alkalinity
Carbonate Alkalinity
Hydroxide Alkalinity
Total Dissolved Solidi
Turbidity
Hexavalenl Chromium
Tola! Chromium
Iron
Lead
Manganese
Nickel
Zinc
Unili
mg/L
mg/L
mg/L
mg/L
mg/L
NTU
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
MCL(a)/SMCL(b)
--
--
--
300.0 (b)
--
--
100.0 (a)
300.0 (b)
15.0 (a)
50.0 (b)
100.0 (a)
5000.0 (b)
Preliminary
Remediation Goals (c)
--
--
--
__
--
--
ia.o
3500.0
--
--
18.0
70.0
1000.0
QP-93-HP-7 (49-50)
03/23/93
NA
NA
NA
NA
NA
NA
10.00 U
NA
NA
NA
NA
NA
NA
QP-93-HP-8 (24-25)
03/24/93
20.0 U
20.0 U
0.0
0.0
1.0 U
6.0
10.00 U
10.0 U
. :' .'. : .. 466.0
3.0 U
15.0 U
40.0 U
20.0 U
QP-93-HP-8 (49-50)
03/24/93
23.0
23.0
0.0
0.0
130.0
36.0
10.00 U
20.0
2670.0
3.4
;" 44.1
40.0 U
20.0 U
QP-9J-HP-9(24-25;
03/25/93
22.0
22.0
0.0
0.0
130.0
15.0
43.00
65.0
953.0
3.0 UJ
15.0 U
40.0 U
20.0 UJ
NA - Not Analyzed Value exceeds either the MCL/SMCL or PRO.
NTU - Ncphelometric Turbidity Uniu
U - Undetected
J - Estimated
(a) Maximum Contaminant Level. Maximum permissible level u establbbed by the Safe Drinking Water Act (40 CFR 141)
for a contaminant in water that is delivered to any user of a public water system. (Lead value is defined ai an'action level* rather than an MCL.)
(b) Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water that primarily affect Ibe aesthetic qualities t(40 CFR 143).
(c) Preliminary Remediation Goals u determined by MDOH.
-------
TABLE 2 (CONTINUED)
'Summary of Push-In Well Screen Groundwatcr Samples
Quality Plaling
Feasibility Study
Sample ID
Dale Collected
Tolal Alkalinity
Bicarbonate Alkalinity
Carbonate Alkalinity
Hydroxide Alkalinity
Tolal Dissolved Solids
Turbidity
Hexavalent Chromium
Tolal Chromium
Iron
Lead
Manganese
Nickel
Zinc
Units
mg/L
mg/L
mg/L
mg/L
mg/L
NTU
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
MCL(a)/SMCL(b)
_-
500.0 (b)
100.0 (a)
300.0 (b)
15.0 (a)
50.0 (b)
100.0 (al
JOOO.O (b)
Preliminary
Remediation Coab (c)
--
--
--
.._
--
--
18.0
3500.0
--
__
18.0
70.0
1000.0
OP-93-HP-9 (49-50)
03/25/93
81.0
79.0
20.0 U
0.0
280.0
30.0
10.00 U
11.0
. 1430.0::
155.0 J
-'- ': ; -uo.o . - ".
40.0 U
20.0 VJ
QP-93-HP-IO(24-25)
03/26/93
20.0 U
20.0 U
0.0
0,0
90.0
12.0
10.00 U
10.0 U
.. . : : 1870.0
.- :. : :.-. " -' 21.6 J
28.1 :
40.0 U
20.0 VJ
QP-93-HP-10(49-50)
03/26/93
84.0
84.0
0.0
0.0
70.0
28.0
10.00 U
10.0 U
2090.0
11.8 J
: ::;.,.: 476.0 :
40.0 U
81.0 VJ
QP-93-HP-11 (24-25)
03/26/93
NA
NA
NA
NA
NA
NA
10.00 U
NA
NA
NA
NA
NA
NA
NA - Not Analyzed Value exceeds either the MCUSMCL or PRO. '
NTU - Nephelomclric Turbidity Units
U - Undetected
J - Estimated
(a) Maximum Contaminant Level. Maximum permissible level as established by the Safe Drinking Water Act (40 CFR 141)
for a contaminant in water that is delivered to any user of a public water system. (Lead value is defined as an "action lever rather than an MCL.)
(b) Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water that primarily affect the aesthetic qualities (40 CFR 143).
(c) Preliminary Remediation Goals as determined by MDOH.
-------
TABLE 2 (CONTINUED)
Summary of Push - la Well Screen Groundwafcr Samples
Quality Plating
Feasibility Study
Sample ID
.Due Collected
Toisl Alkalinity
Bicarbonate Alkalinity
Carbonate Alkalinity
Hydroxide Alkalinity
Total Dissolved Solids
Turbidity
Hexavalenl Chromium
Total Chromium
Iron
Lead
Manganese
Nickel
Zinc
Units
mg/L
mg/L
mg/L
mg/L
mg/L
NTU
ug/U
ug/L
ug/L
ug/L
ug/L
ug/L
ug/L
MCL(aySMCL(b)
--
--
.
500.0 (b)
--
100.0 (a)
300.0 (b)
15.0 (.)
50.0 (b)
100.0 (a)
SOOO.O (b)
Preliminary
Remediation Goals (c)
--
--
--
--
--
18.0
3500.0
--
--
18.0
70.0
1000.0
Or-93-HI'-I2 (24-25)
03/26/93
NA
NA
NA
NA
NA
NA
421.00 ':
NA
NA
NA
NA
NA
NA
OF-9J-HI>-I3 (24-25)
03^26/93
NA
NA
NA
NA
NA
NA
10.00 U
NA
NA
NA
NA
NA
NA
Q|»-93-MI'-K
03/22/93
20.0 U
20.0 U
0.0
0.0
50.0
< 1.0
10.00 U
10.0 U
100.0 U
3.0 U
15.0 U
40.0 U
20.0 U
QP-93-OJ-2J-HP-R
03/23/93
NA
NA
NA
NA
NA
NA
10.00 U
10.0 U
100.0 U
3.0 U
15.0 U
40.0 U
20.0 U
NA - Not Analyzed Value exceeds either Ihe MCL/SMCL or PRO. '
rrru - Nephelomclric Turbidity Units
U - Undetected
1 - Estimated
(a) Maximum Contaminant Level. Maximum permissible level as established by the Safe Drinking Water Act (40 CFR 141)
for i contaminant in water that is delivered to any user of > public water system. (Lead value is defined as in "action lever rather than an MCL.)
(b) Secondary Maximum Contaminant Levels. Regulates contaminant] in drinking water that primarily affect the aulhe tic qualities (40 CFR 143).
(c) Preliminary Remediation Coab as determined by MDOH.
-------
17
5.0 SUMMARY OF SITE CHARACTERISTICS
5.1 INVESTIGATION OBJECTIVES
The objectives of the FIG were to more fully characterize the aquifer at the site and provide a
more in depth evaluation of metals contamination in the groundwater. This section of the ROD
presents the results, summary, and recommendations of the FIG.
5.2 NATURE OF CONTAMINATION
To accomplish the FIG objectives, the groundwater samples collected were analyzed primarily for
metals and geochemical parameters. Parameters for analysis included hexavalent chromium, total
chromium, nickel, iron, lead, zinc, manganese, alkalinity, turbidity, and total dissolved solids. Of
these parameters, hexavalent chromium was considered the primary contaminant of concern at the
site because of its toxicity, solubility, and highly mobile nature. Other metals at die site,
particularly trivalent chromium (a reduced form of chromium), are less soluble and mobil within
the present site conditions. Turbidity was measured to evaluate the representativeness of the
samples. A turbidity level of 50 nephelometric turbidity units was used in the field as a
maximum acceptable level with laboratory measurements of turbidity being conducted to confirm
the field measurements.
5.3 GROUNDWATER WELL SAMPLING
Groundwater monitoring wells (MW-1, MW-2, MW-3, and MW-4), the on-site production well
(WH-1), and off-site nordi and south irrigation wells (IGN and IGS) were sampled and analyzed.
Results of the analyses are presented in Table 1. For evaluation purposes, the maximum
contaminant levels (MCLs) as established by the Safe Drinking Water Act, the secondary
maximum contaminant levels (SMCLs), and the Missouri Water Quality Standards (MWQSs) are
also included.
As indicated in Table 1, hexavalent chromium contamination was detected in on-site monitoring
wells MW-2 and MW-3. The presence of hexavalent chromium in the wells was verified during
resampling. Concentrations of other metals in these wells which were included in the analyses
were below die current standards presented in Table 1. Hexavalent chromium was not detected
in the upgradient wells (MW-1 and the on-site production well) which indicates activities at the
site are the probable source of die hexavalent chromium contamination.
5.4 PUSH-IN WELL SCREEN SAMPLING WITH THE BAILER
Seven push-in screen samples were collected with a bailer, however, the samples were extremely
turbid and are not representative samples. Turbidity in the groundwater samples will cause false
positives or elevated concentrations of low-solubility metals in samples which do not represent
actual groundwater quality conditions. The presence of turbidity also appears to affect the
analysis for hexavalent chromium, a highly soluble metal. Because turbid samples are not
representative, the analytical results of these samples are not considered valid indications of
groundwater quality at the site and are presented in Table 2 for reporting purposes only.
-------
18
5.5 PUSH-IN WELL SCREEN SAMPLING WITH THE PERISTALTIC PUMP
Twenty push-in well screen samples were collected using a peristaltic pump enabling non-turbid,
representative samples to be collected. Results of these samples are presented in Table 2.
Samples were collected from 12 locations and at depths of 25 and 50 feet. Analytical results of
the groundwater samples indicate the on- site and downgradient off-site presence of iron,
manganese, and hexavalent chromium at levels above current water quality standards.
Upgradient groundwater conditions on-site indicate the presence of iron at concentrations above
the current water quality standards. Concentrations of other parameters were below current water
quality standards at the upgradient location. The presence of iron at an upgradient location
suggests iron sampled represents background concentrations.
Manganese was detected at levels above the current water quality standard at on-site and off-site
locations. The presence of manganese at the site appears to be random (higher concentrations
were identified in 50-foot deep samples) with no horizontally spatial pattern and are not above
concentrations commonly found in alluvium soils in southeast Missouri. Therefore, manganese is
considered to be a background contaminant.
Lead was analyzed in twenty samples. Levels of lead were detected in two downgradient samples
above the current water quality standard (15ppb), however, the laboratory quality control
measures invalidated one sample and it could not be considered a valid result. The second
sample appeared to be an isolated natural background concentration since other valid
concentrations of lead above the current water quality standard were not detected.
The presence of hexavalent chromium was identified in several samples collected from on-site and
downgradient off-site locations. The concentrations have been plotted and contoured on Figures
3 and 4. Figure 3 shows the horizontal extent of hexavalent chromium in die aquifer. The
highest concentration (1,206 ppb) of hexavalent chromium was identified in a sample collected in
the area adjacent to the downgradient side of die sludge pit/wastewater lagoon area. The extent
of detectable hexavalent chromium extends approximately 200 feet downgradient (south) of the
southern property boundary of die site.
Hexavalent chromium was not detected in any of the samples collected from the 50-foot bgs zone
of die aquifer. Figure 4 illustrates a generalized cross section of the hexavalent chromium plume
identified in die FIG sampling efforts. The cross section location is also illustrated on Figure 4.
5.6 SUMMARY AND RECOMMENDATIONS FROM THE FIG
Risk-levels for hexavalent chromium and total chromium in groundwater were established in the
Risk Assessment by the Missouri Department of Health (MDOH) for the Quality Plating site.
While detected levels of total chromium were below the risk-level of 3,500 ppb, the risk-level of
18 ppb for hexavalent chromium was exceeded. Analytical results indicate the presence of
hexavalent chromium up to concentrations of 1,206 ppb. The volume of the plume which is
above the risk level is represented in Figures 3 and 4. To develop and evaluate the groundwater
extraction options, a diree dimensional groundwater flow (MODFLOW)/solute transport
(MT3D) model was used. Modeling results demonstrate that the edge of this plume would
migrate an additional 250 feet downgradient over die next 30 years.
-------
19
,38
.
CAO OKC HO: C0003«2<
C PUSH-IN WELL SCREEN SAMPLING LOCATION
Hp_, WITH NUMBER AND HEXAVALENT CHROMIUM
(12061 oo/l CONCENTRATION (DUPLICATE RESULTS IN
PARENTHESES)
FIGURE 3
REPRESENTATIVE PUSH-IN HELL SCREEN
SAILING LOCATIONS INCLUDING K FOOT
BCS HEXftVRLENT CHROMIUM SAMPLING RESULTS
QUALITY PLAT1NC_S1TE
-------
ft
NORTH
310 ,
320
ft'
SOUTH
rHP-5
HP-4
r-HP-12
rHP-3
UJ
UJ
u.
300
z
o
Ul
^ 280
260 I
APPROXIMATE
WASTEHATER
LAGOON AREA
GROUNOWflTER FLOW
DIRECTION
LEGEND
SAMPLE INTERVAL AND HEXAVALENT
1201(1206) CHROMIUM CONCETRATION IN ug/L
(DUPLICATE RESULTS IN PARENTHESIS)
* TURBID SAMPLE. MAY NOT BE
REPRESENTATIVE.
. APPROXIMATE CONCENTRATION CONTOUR
0FOR HEXAVALENT CHROMIUM (IN ug/L)
(SAMPLE DATES 3-22-93 THRU 3-26-33).
C±D
-------
21
Considering that contaminated groundwater which exceeds site-designated risk-levels exists at the
site, and that there are known shallow groundwater users downgradient of the site, remediation of
the groundwater at the Quality Plating site was determined to be warranted.
6.0 SUMMARY OF SITE RISKS
This section explains the risk assessment process. The risks to human health and the
environment at the Quality Plating site are described in the site-specific Risk Assessment for
Exposure to Contaminated Groundwater, which was prepared by the MDOH for MDNR using
EPA guidance. The Risk Assessment followed the following four step process: 1) identification of
contaminants which are of significant concern at the site, 2) an exposure assessment which
identified exposure pathways and calculated contaminant intake, 3) a toxicity assessment for
chemicals of potential concern at the site, and 4) a risk characterization, which integrated the
three earlier steps to summarize the potential and current risks posed by hazardous substances at
the site.
6.1 CONTAMINANT OF CONCERN
Hexavalent Chromium is the contaminant of concern and two assumptions were made regarding
the chemical. First, it was assumed that all chromium was either trivalent or hexavalent because
these are the two most common forms. For purposes of calculating chemical intake, the
concentration of hexavalent measured in groundwater was used as the exposure point
concentration for hexavalent chromium. The exposure point concentration for trivalent
chromium was equal to the measured total chromium concentration minus the measured
hexavalent chromium concentration. Second, chemical concentrations were assumed to remain
constant over time, therefore, future chemical concentrations were assumed to be the same as
those present.
Exposure to contaminated groundwater is generally through ingestion or bathing in water from a
single well since each residence normally has only a single well. It is the policy of EPA Region
VII to use contaminant concentrations in the most contaminated well for exposure point
concentrations. Concentrations in HP4 were highest and used as exposure point concentration in
the risk assessment.
Nickel was not detected in any groundwater sample collected during the FIG and was excluded
from the risk assessment. Lead was detected above detection limits (3 ppb) in six groundwater
samples. In two of the six samples, lead was detected at downgradient locations above the
current water quality standard (15 ppb). The laboratory quality control measures invalidated one
of the results, therefore, it could not be considered a valid result. The second sample above the
water quality standard (21.6 ppb) is an isolated concentration since other valid concentrations of
lead above the current water quality standard were not detected. Lead is believed to represent
natural background concentrations, therefore, it was excluded from the risk assessment. The
remaining four metals: chromium (total and hexavalent), iron, manganese, and zinc were retained
as contaminants of concern in the risk assessment.
-------
22
6.2 EXPOSURE ASSESSMENT
The objective of the exposure assessment is to estimate the type and magnitude of exposures from
the site. This includes identifying exposure routes (ingestion, inhalation, and direct contact), land
use scenarios, potentially exposed populations, estimating exposure point concentrations, and
describing assumptions about exposure frequency and duration.
A conceptual model illustrating potential exposure pathways at the Quality Plating site is shown
in Figure 5. Two potential media of concern (soil and groundwater) are shown in Figure 5.
Contaminated soil was removed from the site during a removal action in August and September
1992, therefore, soil was not considered as a media of concern in the risk assessment.
Groundwater samples have been collected on-site and off-site. On-site samples collected during
the FIG showed elevated metal concentrations, therefore, on-site groundwater was retained as a
media of concern for the risk assessment. Off-site groundwater samples from nearby private wells
have been collected annually by the MDOH since 1988. Elevated metal concentrations have not
been found in any of these samples, indicating that groundwater contamination has not reached
the residential wells. Off-site groundwater was excluded from further consideration in the risk
assessment. Because land use surrounding the Quality Plating site is mixed agricultural and
residential, residential exposure scenarios were used to estimate risks from exposure to the site. A
residential scenario is generally the most conservative scenario and will result in the highest risk
estimates. Industrial use at the site is not expected, thus occupational exposure scenarios were not
conducted. It is possible that trespassers could cross the site, however, it is unlikely that
trespassers would be exposed to groundwater. A trespasser scenario was not evaluated.
The site is currendy used for agriculture purposes and it is unlikely that there is human exposure
to the groundwater on-site. The surrounding area is a mixture of residential and agriculture.
While area residents obtain their drinking water from individual shallow wells, no contamination
has been detected in the MDOH sampling. If no action is taken, residential wells in the path of
the migrating contaminated plume are at risk. Because there does not appear to be any exposure
to contaminated groundwater at the Quality Plating site, no current exposure scenarios were
evaluated in the risk assessment.
One important aspect of calculating the risk for a site is the concept of Reasonable Maximum
Exposure (RME). The RME is an estimate of the highest exposure that is reasonably expected to
occur at a site. Two RME's were evaluated in the risk assessment for the Quality Plating site: a
70 kg future adult resident (RME1) and a 15 kg future child resident (RME2) living on the site.
The adult ingests 2 L of contaminated groundwater a day and bathes with contaminated
groundwater 15 minutes a day over a 30 year period while living on the site. The child ingests
1 L of contaminated groundwater a day and bathes with contaminated groundwater 15 minutes a
day over a 6 year period while living on the site.
6.3 TOXICITY ASSESSMENT PROCESS
The first step of the toxicity assessment, hazard identification, weighs the available evidence
regarding the potential for contaminants of concern to cause adverse effects in exposed
individuals. The second step of the toxicity assessment, dose-response evaluation, quantitatively
evaluates the toxicity information and characterizes the relationship between the dose (in mg/kg-
day) and the incidence of adverse health effects in the exposed population.
-------
23
Figure 5
Conceptual Model
Quality Plating Superfund Site
Scott County, MO
Human
Receptor
Soil
Removal
Action
Key
Contaminated
media
Receptor
-------
24
6.3.1 NON-CARCINOGENIC EFFECTS
Oral Reference Doses (RfD) were the toxicity values used in assessing non-carcinogenic effects
from oral exposure. Contaminate-specific RfD values used in the risk assessment were derived
from EPA Integrated Risk Information System (IRIS) and EPA Health Effects Assessment
Summary Tables (HEAST).
To assess non-carcinogenic effects from dermal exposure, oral RfDs must be adjusted from the
administered doses to absorbed doses. This is accomplished using the following formula:
Absorbed RfD = (Administered RfD) (Oral Absorption Efficiency)
Calculated absorbed RfD doses are presented in Table 3.
6.3.2 CARCINOGENIC EFFECTS
Hexavalent chromium is a known human carcinogen when inhaled as a dust. Hexavalent
chromium has not been found to cause cancer when ingested in food or water. No oral Slope
Factor (SF) exists for hexavalent chromium. SFs are used to assess carcinogenic effects for specific
contaminants. A SF is the plausible upper-bound estimate of the probability of a response
(cancer) per unit intake of a chemical expressed over a lifetime.
6.4 RISK CHARACTERIZATION
Non-cancer hazard quotients were calculated for each contaminant in each pathway by dividing
the Intake or Absorbed Dose by the RfD. The non-cancer hazard quotients within an exposure
pathway were summed to give the pathway hazard index. The Total Hazard Index was then
calculated by summing the pathway hazard indices. Human healdi risks may exist when the
Total Hazard Index exceeds unity (1.0).
The Total Hazard Index for the adult resident was 7.9 and is presented in Table 4. Ingestion of
groundwater contributed substantially to the Total Hazard Index (7.1) with hexavalent chromium
as the chemical which contributed the most risk (6.9).
The Total Hazard Index for the child resident was 5.0 and is presented in Table 5. The
groundwater pathway and chromium contributed to the child's Total Hazard Index similar to
those calculated in the adult resident scenario. A summary of the hazard index values for RME1
and RME2 is presented on Table 6.
6.5 UNCERTAINTIES
The estimation of risk posed at a site involves several areas of uncertainty in the determination of
chemical intake and toxicity. Daily chemical intake is estimated using a variety of variables. The
values used for most intake variables are 95% upper confidence limit of the mean variable value.
This is done in an attempt to ensure the protection of public health, but it may overestimate the
true risk posed at a site. Most of the toxicity values used to calculate risks are derived from tests
carried out on animals. Interspecific, as well as intraspecific variation adds uncertainty to the
toxicity values, therefore, the true risks posed may be higher or lower than those presented in the
risk assessment.
-------
25
TABLE 3
Summary of Calculated Absorbed Toxicity Values
Further Investigation of Groundwater
Quality Plating Site, Sikeston, MO
Chronic Chronic Subchronic Subchronic
Administered Absorbed Administered Absorbed
Chemical
Chromium VI
Chromium 117
Manganese
Zinc
Oral
Absorption
Efficiency
0.021
0.004
0.03
0.33
Reference
Dose
(mg/kg/d)
0.005
1.0
0.005
0.3
Reference
Dose
(mg/kg/d)
0.00011
0.004
0.00015
Inappropriate
Reference
Dose
(mg/kg/d)
0.02
10
0.005
0.3
Reference
Dose
(mg/kg/d)
0.00042
0.04
0.00015
Inappropriate
Inappropriate - Oral to dermal route extrapolation is
not appropriate for this chemical (Appendix D).
-------
TABLE 4
Quality Plating Site, Sikcston, MO
Further Investigation of Groundwatcr
Ha/ard Index Values for RME1
Ingestion of 2 L/day of contaminated drinking water by a 70 kg adult 365 days/year over a 30 year period
Chemical
Hexavalent Chromium
TrivaJcnt Chromium
Manganese
Zinc
Concentration
(mg/L)
1.206
0.254
0.0406
0.021
Dermal contact with contaminated water
Chemical
Hexavalent Chromium
TrivaJent Chromium
Manganese
Concentration
(mg/kg)
1.206
0.254
0.0406
Intake
(mg/kg/d)
0.035
0.0073
0.0012
0.0006
Intakc/RfD
Adjusted for
Absorption
no/no
no/no
no/no
no/no
RfD
(mg/kg/d)
0.005
1
0.005
0.3
by a 70 kg adult bathing 15 minutes/day over a 30
Final Intake
(mg/kg/d)
0.000063
0.000013
0.0000021
RfD/Intake
Adjusted for
Absorption
yes/yes
yes/yes
yes/yes
Total Hazard Index
RfD
(mK/kR/d)
0.000105
0.004
O'.OOO 15
Ha/ard
Quotient
6.9
0.0073
0.23
0.0020
year period
Ha/ard
Quotient
0.60
0.0033
0.014
Pathway
Ha/ard
Index
7.1
Pathway
Ha/ard
Index
0.61
7.7
-------
TABLE 5
Quality Plating Site, Sikcston, MO
Further Investigation of Groundwntcr
Ha/ard Index Values for RME2
Ingestion of 1 L/day of contaminated drinking water by a
Chemical
Hexavalent Chromium
Trivalent Chromium
Manganese
Zinc
Maximum
Detected
Concentration
(mfi/L)
1.206
0.254
0.0406
0.021
Dermal contact with contaminated water
Chemical
HexavaJent Chromium
Trivalent Chromium
Manganese
Concentration
(mg/kg)
1.206
0.254
0.0406
Intake
(mg/kg/d)
0.08
0.017
0.0027
1 0.0014
by a 15 kg child
Final Intake
(mg/kg/d)
0.00012
0.000024
0.0000039
15 kg child 365 days/year over a
Intakc/RfD
Adjusted for
Absorption
no/no
no/no
no/no
no/no
RfD
(mg/kg/d)
0.02
10
0.005
0.3
bathing 15 minutes/day over a 6
RfD/Intake
Adjusted for
Absorption
yes/yes
yes/yes
yes/yes
RfD
(mg/kg/d)
0.00042
, 0.04
0.00015
6 year period.
Hazard
Quotient
4.0
0.0017
0.54
0.0047
year period
Hazard
Quotient
0.28
0.00061
0.026
Total Hazard Index
Pathway
Hazard
Index
4.6
Pathway
Hazard
Index
0.30
4.9
-------
28
TABLE 6
Summary of Noncarcinogenic Risks
Further Investigation of Groundwater
Quality Plating Superfund Site
Sikeston, MO
RME1 - Residential Adult
Pathway Hazard Index
Total Hazard Index
HP 4
Ingestion
7.1
Dermal Contact
0.61
7.7
RME2 - Residential Child
Pathway Hazard Index
Total Hazard Index
HP 4
Ingestion
4.6
Dermal Contact
0.30
4.9
-------
29
Several areas of uncertainty are specific to this site. Because chemical concentrations from only
one groundwater sample were used to estimate intake, the concentrations in groundwater may
have been over or underestimated. This would result in an over or underestimation of risks
posed by the site. Also chemical concentrations in groundwater were assumed to remain constant
over time.
6.6 CONCLUSIONS
The greatest risk at the site is due to non-carcinogenic effects from hexavalent chromium
contamination in the groundwater. The contaminated groundwater, if not addressed by
implementing the response action selected in this ROD, may present an imminent and substantial
endangerment to public health.
7.0 REMEDIAL ACTION OBJECTIVES
Remedial Action objectives define the allowable exposures to contaminants of concern found at
the Quality Plating site. The primary contaminant of concern is hexavalent chromium and the
objectives addressing hexavalent chromium will also address human health risks with other site
contaminants.
The National Contingency Plan [40 CFR 300.430(a)(iii)(F) states "EPA expects to return usable
ground waters to their beneficial uses whenever practicable,..." At this site there are nearby
residents who use shallow groundwater as their source of drinking water. The groundwater will
be treated to meet site-specific goals for drinking water and the treated effluent will meet
Missouri Water Quality Standards and NPDES discharge limitations established by MDNR prior
to discharge.
Since the risk assessment did not identify carcinogenic risks at the Quality Plating site, the
following Remedial Action Objectives were developed:
1) Prevent ingestion of water having non-carcinogenic contaminants in excess of MCLs or
preliminary remediation goals (PRGs) as determined from adverse non-carcinogenic
effects. MCLs and PRGs identified for this site by the MDOH are presented in Table 7.
PRGs are those cleanup goals established for a specific contaminant by MDOH and is
based upon the risk assessment.
2) Prevent migration of contaminants to protect wild and domesticated plant and animal life
and prevent degradation of natural resources.
8.0 DESCRIPTION OF ALTERNATIVES
The remedial alternatives evaluated in detail in the FS report are described in the following
subsections and are summarized in Table 8. These descriptions identify engineering components,
institutional controls, implementation requirements, estimated costs, and major Applicable or
Relevant and Appropriate Requirements (ARARs) associated with each alternative.
With the exception of the "No Action" alternative, all of the alternatives considered for this site
have a number of common elements. These common elements include neutralization and
-------
30
Table 7
Final Groundwater Preliminary Remediation Goals
Quality Plating Site
Chemical
Chromium VI
Chromium, Total
Iron
Lead
Manganese
Nickel
Zinc
Maximum
Concentration
Detected in
Groundwater
Onsite or On
Adjacent
Properties
G*g/L)
1,206
1,460
15,200
21.6
690
40 U
30
Final
Preliminary
Remediation
Goal Obtg/L)
18
3,500
(b)
00
18
70
1,000
Maximum
Contaminant
Level
(Mg/L)(a)
100
300
15W
~
100
U Undetected.
w Maximum Contaminant Level. Maximum permissible levels as established by the Safe
Drinking Water Act (40 CFR 141) for a contaminant in water that is delivered to any
user of a public water system.
m Toxicity data are insufficient for quantitative risk assessment.
(c| Secondary Maximum Contaminant Levels. Regulates contaminants in drinking water
that primarily affect the aesthetic qualities (40 CFR 143).
(d) Lead value is defined as an "action level" based on treatment technology rather than an
MCL.
-------
31
TABLE 8
Groundwater Alternatives
Quality Plating Site
General Response Action
Technology/Process Option
No Action
Groundwater Alternatives
Institutional Controls'
Groundwater Monitoring
Containment (50 gpm)
Active Restoration (150 gpm)
traction Wells
gpm)
Extracted Groundwater Treatment
Coagulation/Flocculation
Neutralization
Reduction
Precipitation
Ion Exchange
Treated Groundwater Disposal
POTW
Ditch No. 4
40248.101
-------
32
reduction of contaminants, extraction wells and groundwater monitoring.
Neutralization and reduction - The extracted groundwater is pumped to the influent
holding tank and discharged to a chemical reduction tank Hexavalent chromium is
reduced to the trivalent form using either electrochemical or chemical reduction. When
using chemical reduction sulfuric acid would be added to a reduction tank to reduce the
Ph alkalinity of the groundwater. Following Ph reduction, a chemical such as ferrous
sulfate would be added to react with hexavalent chromium and reduce it to trivalent
chromium.
Extraction wells - Groundwater extraction wells would be installed and built similar in
type and construction to domestic or municipal water supply wells. The exact size,
location and pumping capacity will be determined through hydrogeological analysis during
die remedial design phase.
Two well extraction scenarios are considered. A "containment" scenario extracts
contaminated groundwater at a rate sufficient to contain the plume during remediation.
An "active restoration" scenario extracts contaminated groundwater at a more aggressive
rate.
Groundwater monitoring - Groundwater monitoring would serve to detect changes in the
migration of contaminants and to indicate the effectiveness of any remedial actions,
however, they would not treat or reduce the contamination. Monitoring wells would be
added to the existing network of monitoring wells to provide additional definition of the
contaminated plume. In addition, a sampling and chemical analysis plan would be
implemented.
8.1 ALTERNATIVE 1: NO ACTION
The no action alternative is required by CERCLA to be developed and serves as a baseline for
comparison with the cleanup alternatives. Under this alternative, no action would be taken to
remove the groundwater contaminants, however, a 5-year review of the site would be required
under CERCLA. Funds would be expended to conduct the review. Since this alternative does
not change the contamination concentration or exposure, the risk remaining at the site would be
equivalent to the current estimated risks based on the risk assessment results. Consequently, this
alternative is not protective of human health and the environment and does not meet ARARs in
that the groundwater does not currendy meet the chemical-specific ARARs. Modeling results
indicate that the plume would degrade to below the PRG by natural precesses in 500 years and
would migrate approximately 3,000 feet to the south-southwest from the site.
Capital Costs: $0
Annual O&M (Operation and Maintenance) Costs
(5-year review): $2,600
Total Present Worth (PW): $10,700
Months to Implement: Immediate
-------
S; A; K.:.p....V
DITCH NO. 4 -y
w - l<
-X
DITCH NO. 4
DISCHARGE
QUALITY PLATING
FIGURE 6
LOCATION OF DISCHARGE J>j
s* , TO DITCH NO. 4 AND POTW*3
3-*^ QUALITY PLATING SITE
-------
TABLE 9
Cost Sensitivity Analysis
Quality Plating Site
Cost
Sensitivity
Parameter;
Original
Present
Worth (7
percent
discount
rale)
Discount
Rate
5 Percent
10 Percent
Double
Remediation
Time
Substitute
Chemical
Reduction
for Elcctro-
chcmic.il
Reduction
Alternative 1
Total
Present
Worth
SI 0,700
$11,700
SV.300
..
Percent
Change*
.
9.3%
13%
Alternative 2
Total
Present
Worth
$1,057,000
$1,080.000
$1,027,000
$1,236.000
$1.305.000
Percent
Change'
..
2%
-0.3%
17%
23%
Alternative 3
Total
Present
Worth
$1,166,000
$1,170.000
$1,159,000
$1,309,000
$1,438,000
Percent
Change*
0.3%
-0.6%
12%
23%
Alternative 4
Total
Present
Worth
$954,000
$972.000
$930.000
$1.094,000
$1.285.000
Percent
Change*
..
2%
-2%
15%
35%
Alternative 5
Total
Present
Worth
$993,000
.
$998.000
$988.000
$1,121,000
$1.315,000
Percent
Change*
_
0.5%
-0.5%
13%
32%
Alternative 6
Total
Present
Worth
$961,000
$987,000
$927.000
$1,163,000
..
Percent
Change*
3%
-4%
21%
..
Alternative 7
Total
Present
Worth
$1,475,000
$1.482.000
$1.466,000
SI. 67 1.000
..
Percent
Change
-,
0.5%
-0.6%
13%
..
Refers to the percent change in cost from the original present worth estimate.
-------
35
8.2 ALTERNATIVE 2: CONTAINMENT/REDUCTION/PRECIPITATION
Alternative 2 involves extraction of contaminated groundwater through an extraction well,
treatment of the contaminated groundwater by reduction/precipitation, and discharge of the
treated groundwater to Ditch Number 4 approximately 4,000 feet east of the site as shown on
Figure 6. The discharge would be under the authority of a state operating permit. Discussion
with Scott County road personnel have indicated the routing of the discharge pipe along Scott
County Road 448 would be acceptable. Two primary treatment processes, chemical reduction
and electrochemical reduction, could be used to reduce the hexavalent chromium to the less toxic
trivalent chromium. During the remedial design, tests will be completed to determine which
process is more appropriate for this specific site. To evaluate alternatives, it is assumed that a
chemical process will be utilized. A cost comparison between electrochemical and chemical
treatment is shown as part of the Cost Sensitivity Analysis presented in Table 9.
In the chemical reduction system, the extracted groundwater would be pumped from the
extraction well system to the influent holding tank for flow equalization. Groundwater would
then be discharged to the chemical reduction tank where sulruric acid would be added to reduce
the Ph alkalinity of the groundwater. With the addition of a chemical, such as ferrous sulfate,
the treatment system would then reduce the hexavalent chromium to the less toxic trivalent
chromium. Trivalent chromium would be precipitated out of solution as chromium hydroxide
and pumped to a sludge holding tank where the sludge would be dewatered using a filter press,
characterized, and then sent off-site for proper disposal. The MDNR's Water Pollution Control
Program has indicated the treated groundwater discharge to Ditch Number 4 would be limited to
0.28 mg/L total chromium. It is anticipated that chemical reduction will remove approximately
90% of the total chromium from the groundwater being treated. This process would be expected
to provide a treated discharge significantly lower that the 0.28 mg/L total chromium effluent
limit.
The extraction well would be constructed of 6-inch PVC pipe to a total depth of 35 feet bgs
(below ground surface) and be screened for a 20 foot interval. A pumping rate of 50 gallons per
minute (GPM) would be used to contain the plume. Figure 7 shows the approximate location of
die extraction well (EX-1) for this alternative.
Institutional controls (a groundwater monitoring program) would be implemented to monitor the
plume and remediation process. A groundwater monitoring plan would be necessary.
Capital Costs: $762,000
Annual O&M: $52,000
Total PW: $1,057,000
Months to Implement: 10 months to plant startup; treatment would take 7 to 8 years.
8.3 ALTERNATIVE 3: ACTIVE RESTORATION/REDUCTION/PRECIPITATION
Alternative 3 entails extraction of contaminated groundwater through the use of two extraction
wells, treatment of contaminated groundwater by chemical reduction/precipitation, and discharge
of treated groundwater to Ditch Number 4. Each extraction well would be pumped at 75 gpm
or a total flow rate of 150 gpm. The extraction wells would be constructed similarly to die
extraction well in Alternative 2. Figure 8 shows the approximate location of the extraction wells
(EX-1 and EX-2) used in this alternative. The groundwater treatment process for Alternative 3
-------
100' 50' 0 100' 200'
36
'Li.-fJTV-
»> i . «JT u
s
%-
^l.-u
OM-39
OH-4B
LFCEND
OM-1RCCOH-1B PROPOSED LOCM10N FOR OBSERVATION KELL/HELL
C NEST AND NUMBER I* « IS FEET DEEP. B ' 25
OH-1C FEET DEEP. C SO FEET DEEP)
KM-1
EXISTINC MONITORING HELL
LOCATION AND NUMBER
-*- PROPOSED LOCATION FOR THE
£X.j EXTRACTION HELL AND NUMBER
_<10 £.,, CONCENTRATION CONTOUR FOR HEXAVALENT
lg W-'L~- CHROMIUM (SAMPLE DATES 3-22-93 TO 3-26-S3I
FIGURE 7
CONTAINMENT EXTRACTION
HELL LOCATION
_~-. ... p, .TtMfr CITT
-------
37
to i . MJ «j r
«,,,-.-< .»,!
i
100' 50' 0
100' 200'
»- i. . -»J U
OH-3B
OH-4B
OH-lACOOH-lB PROPOSED LOCMtOM FOR OBSERVATION HELL/HELL
C NEST AND NUMBER lA « IS FEET DEEP. B « 25
OH-1C FEET DEEP. C SO FEET DEEP!
KM- 1
EX1STINC MONITORING HELL
LOCATION AND NUMBER
A
10 UCA.-
PROPOSED LOCATION FOR THE
EXTRACTION HELL AND NUMBER
CONCENTRATION CONTOUR FOR HEXAYALENT
CHROMIUM (SAMPLE DATES 3-22-93 TO 3-26-S3)
FIGURE 8
ACTIVE RESTORATION
EXTRACTION HELL LOCATION
DUALITY PLAIINC SITE
-------
38
would be similar to the process described in Alternative 2, and it would require similar
institutional controls as those being required in Alternative 2.
Capital Costs: $1,001,000
Annual O&M: $91,000
Total PW: $1,166,000
Months to Implement: 10 months to plant startup; treatment would take 2 years.
8.4 ALTERNATIVE 4: CONTAINMENT/REDUCTION
Alternative 4 entails extraction of contaminated groundwater through the use of one extraction
well, treatment of contaminated groundwater by chemical reduction, and discharge of treated
groundwater to the local Public Owned Treatment Works (POTW) which is approximately 5
miles south in Sikeston, Missouri. The alignment of the effluent pipe to the POTW is shown on
Figure 6. The location of the proposed well would be that as selected in Alternative 2, pumped
at a rate of 50 gpm to provide plume containment, and similar in construction to the extraction
well in Alternative 2.
Extracted groundwater would be pumped to an influent holding tank for flow equalization.
Groundwater would then go to the chemical reduction tank where sulfuric acid would be added
to reduce the Ph and reduce the groundwater's natural alkalinity. Following Ph reduction, the
treatment process would reduce the hexavalent chromium to trivalent chromium by the addition
of a chemical reagent, such as ferrous sulfate. Treated groundwater would then be discharged
directly to the POTW under the authority of a pretreatment agreement with the city of Sikeston.
The proposed routing of die discharge pipe to the POTW would be placed in the easement
already obtained by Scott County for Scott County roads. Discussions with Scott County
officials have indicated that routing of the discharge pipe along Scott County roads would be
acceptable. In this alternative, residual waste would not be generated because chromium
wouldnot be precipitated out of die groundwater. Institutional controls as identified in
Alternative 2 would apply.
Capital Costs: $721,000
Annual O&M: $41,200
Total PW: $954,000
Months to Implement: 10 months to plant startup; treatment would take 7 to 8 years.
8.5 ALTERNATIVE 5: ACTIVE RESTORATION/REDUCTION
Alternative 5 removes contaminated groundwater through die use of two extraction well, treats
the contaminated groundwater by chemical reduction, and discharges the treated groundwater to
die Sikeston POTW. Two extraction wells would be located similarly to positions chosen for
Alternative 3. Each well would be pumped at a rate of 75 gpm for a total flow rate of 150 gpm.
The treatment process, discharge, and institutional controls would be the same as those in
Alternative 4.
Capital Costs: $847,000
Annual O&M: $81,000
Total PW: $993,000
Mondis to Implement: 10 mondis to plant startup; treatment would take 2 years.
-------
39
8.6 ALTERNATIVE 6: CONTAINMENT/ION EXCHANGE
Alternative 6 entails extraction of contaminated groundwater through the use of one extraction
well, treatment of contaminated groundwater by ion exchange, and discharge of the treated
groundwater to Ditch Number 4. The construction of the extraction well would be similar to
that in Alternative 2. The extraction well would be pumped at approximately 50 gpm.
Extracted groundwater would be pumped into the influent holding tank for flow equalization.
The influent would than be sent to the anion exchanger where hexavalent chromium is removed
by the ion exchange process. Following hexavalent chromium removal, trivalent chromium would
be removed in the cation exchanger. The ion exchange is a process in which wastewater is passed
through a bed of insoluble exchange material called resin. As wastewater is passed through the
resin, chromium ions are exchanged on the surface with other negatively charged ions of less toxic
elements. As a result, chromium is removed from the wastewater and bound up in the resin
particles. It is anticipated that this process will remove nearly 100% of the total chromium from
the groundwater being treated.
Periodically, the ion exchange resin will become saturated with chromium and require
regeneration. Regeneration would be conducted on-site without removing the resin from the
exchangers. To regenerate the ion exchange resin, sulfuric acid and sodium hydroxide would be
passed through the anion exchanger, and only sulfuric acid would be passed through the cation
exchanger. Regenerate solution exiting the exchangers would be routed to the chemical
reduction/precipitation batch tank. Sulfuric acid and ferrous sulfate would be added to reduce
and precipitate the chromium out of the regenerate solution as chromium hydroxide. The
resulting solution would be routed to the filter press, and the sludge would be characterized and
shipped off-site for disposal.
Institutional controls would be implemented at the site (monitoring wells would be installed) and
a groundwater monitoring and sampling analysis plan would be necessary. As was indicated in
Alternative 2 and 3, the Scott County officials have indicated that routing the discharge pipe
along Scott County Road 448 would be acceptable.
Capital Costs: $629,000
Annual O&M: $59,000
Total PW: $961,000
Months to Implement: 10 months to startup; treatment would take 7 to 8 years.
8.7 ALTERNATIVES ACTIVE RESTORATION/ION EXCHANGE
Alternative 7 will extract contaminated groundwater through the use of two extraction wells,
treatment of the contaminated groundwater by ion exchange, and discharge to Ditch Number 4.
The extraction wells would be pumped at 75 gpm each for a total flow rate of 150 gpm.
Construction of the extraction wells would be similar to diat described in Alternative 2. The
process units and the ion exchange treatment process would be similar to that describe in
Alternative 6. In addition, the common elements associated with the institutional controls as
described in Alternative 2 would be applicable to Alternative 7.
Capital Costs: $1,251,000
Annual O&M: $124,000
-------
40
Total PW: $1,475,000
Months to Implement: 10 months to plant startup; treatment would take 2 years.
9.0 SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
Alternative remedial actions were developed to respond to the contamination at the Quality
Plating site. The alternatives described in the preceding section were evaluated using criteria
related to the factors set forth in Section 121 of CERCLA and the NCP (National Oil and
Hazardous Substances Pollution Contingency Plan). The nine criteria are described below.
Threshold Criteria:
Overall Protection of Human Health and the Environment. This criterion addresses
whether a remedy provides adequate protection to human health and the environment and
describes how risks from each pathway are eliminated, reduced, or controlled through
treatment, engineering controls, or institutional controls.
Compliance With ARARs. This criterion addresses whether a remedy will comply with
chemical-specific, action-specific, and location-specific ARARs and with other criteria,
advisories and guidance such as To Be Considered (TBCs), or provide grounds for a
waiver. TBCs are further discussed in Section 11.2.4.
Primary Balancing Criteria:
Long-Term Effectiveness and Permanence. This criterion refers to the magnitude of
residual risk, including die ability of a remedy to maintain reliable protection of human
health and the environment over rime once cleanup goals have been met, and the
adequacy and reliability of engineering and institutional controls.
Reduction in Toxicity, Mobility, and Volume through Treatment. This criterion assesses
the anticipated performance of the treatment technologies that may be employed in a
remedy.
Short-Term Effectiveness. This criterion refers to the speed with which the remedial
response objectives are achieved, as well as the remedy's potential to have adverse impacts
on human health and the environment during the construction and implementation
periods.
Implementability. This criterion assesses the technical feasibility for constructing and
operating a remedy; the technical and administrative reliability of a remedy, including the
availability of materials and services needed to implement the chosen remedy, and the ease
of undertaking additional action, if necessary.
Cost. This criterion includes the capital, operation and maintenance (O&M), and present
worth cost of a remedy.
-------
41
Modifying Criteria:
State Acceptance. This criterion assesses whether, based on its review of the FIG/FS and
Proposed Plan, the state agency concurs, opposes, or declines to comment on the
preferred alternative.
Community Acceptance. This criterion assesses the degree of community acceptance of a
remedy. The degree of community acceptance can generally be determined as a result of
a review of comments received during the public comment period.
9.1 OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
All of the alternatives, with the exception of Alternative 1, the "No Action" alternative, provide
protection of human health and the environment by reducing and eliminating risks through
treatment, engineering, and institutional controls. Alternatives 6 and 7 provide the greatest
overall protection by removing nearly 100% of the total chromium from the groundwater.
Based upon groundwater modeling extractions results, Alternatives 2, 4, and 6 provide protection,
but risks would remain for 7-8 years until groundwater cleanup goals are achieved. Alternatives
3, 5, and 7 achieve these results in 2 years.
Alternatives 4 and 5 discharge treated groundwater to the POTW after hexavalent chromium has
been reduced to trivalent chromium. According to the POTWs wastewater permit, sludge from
the POTW is currently being land applied, therefore, Alternatives 4 and 5 could result in the
chromium extracted from Quality Plating being land applied in an uncontrolled manner. If
uncontrolled and not properly monitored, this could lead to elevated levels of chromium in soil
where land application occurs, however, the city of Sikeston's Sewer Use Ordinance and a
properly constructed pretreatment agreement could address these concerns.
Alternatives 6 and 7 (ion exchange alternatives) would remove nearly 100% of the total
chromium from the contaminated groundwater and would generate a regeneration solution
concentrated with hexavalent chromium. This hexavalent chromium solution could potentially be
reclaimed by recyclers, thus avoiding the disposal of chromium residuals in a landfill. Alternatives
2 and 3 remove approximately 90% of the total chromium and provide protection to human
health and the environment by achieving the PRG for chromium and meeting discharge
requirements for the treated groundwater. Alternative 7 provides for active restoration (2 years)
and it removes nearly 100% of the total chromium prior to discharge.
9.2 COMPLIANCE WITH ARARs
All alternatives, with the exception of the "No Action" alternative, would comply with federal and
state ARARs. Disposal of the sludge and solid wastes generated at the site will need to be
managed in accordance with the Solid Waste Disposal Act, DOT Hazardous Materials
Transportation Act, Missouri Solid and Hazardous Waste laws and Rules, and the Missouri
Hazardous Substance Rules. Discharges of treated groundwater from the site will need to be
managed in accordance with the Clean Water Act, Missouri Clean Water Law, Missouri Water
Quality Standards, and Missouri Water Pollution Control Regulations. All activities at the site
will need to comply with the Occupational Safety and Health Act.
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Because Alternative 1 did not meet the criteria presented in Subsections 9.1 and 9.2, it was not
compared in the analysis with the Primary Balancing Criteria.
9.3 LONG-TERM EFFECTIVENESS AND PERMANENCE
All alternatives (except Alternative 1) would essentially eliminate the long-term risks associated
with the contaminated groundwater extracted and treated during remediation, however,
Alternatives 6 and 7 would remove both hexavalent and trivalent chromium to a greater degree
than Alternatives 2 through 5. In addition, Alternative 7 provides for better protection of long-
term risk with groundwater remaining in the aquifer than does Alternative 6 because, being an
active restoration alternative, it will achieve cleanup goals approximately 5.5 years sooner.
9.4 REDUCTION OF TOXICITY, MOBILITY, OR VOLUME THROUGH TREATMENT
All alternatives (except Alternative 1) are capable of restoring die contaminated groundwater to
the PRG, however, the different treatment processes vary in their ability to remove total
chromium from the treated groundwater to be discharged. While Alternatives 2 through 5 all
reduce hexavalent chromium, only Alternatives 2 and 3 remove the chromium as a precipitate.
Alternatives 4 and 5 discharge the trivalent chromium to the POTW. Alternatives 6 and 7
remove hexavalent chromium and removes trivalent chromium as a precipitate.
Alternatives 2, 4, and 6 treat approximately 210 million gallons of contaminated groundwater,
while Alternatives 3, 5, and 7 treat approximately 157 million gallons of contaminated
groundwater. In addition, Alternatives 2 and 6 generate approximately 15,200 pounds of sludge
and Alternatives 3 and 7 generate approximately 11,600 pounds of sludge. Alternatives 4 and 5
do not generate sludge.
While Alternatives 2 through 7 all meet the statutory preference for treatment as a principal
element, Alternatives 6 and 7 provide the largest reduction in toxicity, mobility, and volume.
9.5 SHORT-TERM EFFECTIVENESS
Alternatives 2 through 7 would all provide similar community risks. Community risk would be
low during the installation of the extraction well(s) and the treatment facility. There would be a
greater risk to workers but compliance with OSHA requirements and guidelines for hazardous
waste site activities would minimize these. Analysis for air emissions would not be necessary
because the contaminate is a heavy metal and will not volatilize into the air pathway.
Environmental impacts resulting from the installation of the well(s) and treatment system would
include noise pollution and minimal fugitive dust emissions during construction, during
extraction and monitoring well construction, sedimentation and erosion controls would be
implemented to minimize contact with contaminated soil removed from the contaminated
aquifer.
As with community risks, risks to workers and the environment would be similar in all
alternatives, however, in the active restoration alternatives (Alternatives 3, 5, and 7) workers and
equipment would be removed from the site faster than under the containment scenarios. The
time required for design and construction would be similar for all alternatives.
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9.6 IMPLEMENTABILITY
The technical feasibility of all alternatives (except Alternative 1) would be similar because process
options employed in all alternatives are proven and reliable. Alternatives 4 and 5 may prove to
have less operational difficulties because they will not provide a chromium precipitate at the site.
The administrative feasibilities of Alternatives 4 and 5 may be more difficult to implement than
other alternatives because they would require acceptance of the wastewater discharge to the
POTW and an agreement with the city of Sikeston regarding appropriate pretreatment
requirements. The availability of materials and services would be the same for all alternatives.
Alternatives 2 and 3 would equally provide the best overall implementability because the chemical
reduction/precipitation process is very reliable, and POTW agreements are not needed.
9.7 COST
Alternative 4 has the lowest total present worth cost ($954,000). Alternative 7 has the highest
total present worth cost ($1,475,000). The total present worth cost of Alternatives 2, 3, 5, and 6
are $1,057,000, $1,166,000, $993,000, and $961,000. While electrochemical reduction offers no
additional advantages, it could be substituted for chemical reduction in Alternatives 2 through 5.
If electrochemical reduction is substituted for chemical reduction, costs would be increased and
the new present worth cost and the percentage of increase would be as follows: Alternative 2,
$1,305,000 (23%); Alternative 3 $1,438,000 (23%); Alternative 4, $1,285,000 (35%); and
Alternative 5, $1,315,000 (32%).
9.8 STATE ACCEPTANCE
MDNR wrote the Proposed Plan for this site on which this ROD is based. Furthermore, MDNR
concurs with this ROD.
9.9 COMMUNITY ACCEPTANCE
Community acceptance is specifically addressed in the attached Responsiveness Summary. The
Responsiveness Summary provides a through review of the significant public comments received
on the FS and Proposed Plan, and responses to the comments. The community has indicted
general agreement with the remedy selected in this ROD.
10.0 SELECTED REMEDY
Based upon consideration of the requirements of CERCLA and the NCP, the evaluation of the
relative performance of each alternative with respect to the nine criteria, and consideration of
comments received during the public comment period, EPA has determined that Alternative 3 is
the selected remedy. This selected remedy includes: Two extraction wells each pumping at a rate
of 75 gpm would be constructed. Treatment would be provided by chemical reduction and
precipitation.
Approximately 210 million gallons of contaminated groundwater would by treated and
approximately 11,600 pounds of sludge would be generated. The sludge would be characterized
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and properly disposed of off-site at an EPA approved facility. Nearly 90% of the total chromium
would be removed and the treated effluent would be discharged to Ditch Number 4. The length
of time required for remediation would be 2 years and constructed at an estimated cost of
$1,001,000. Annual O&M costs are estimated at $91,000.
The selected remedy would reduce the hexavalent chromium in the groundwater to 0.018 mg/L
and provide an effluent which would meet the Missouri Water Quality Standards for 0.28 mg/L
for Total Chromium for the receiving stream.
Additional monitoring wells will be added to die existing field of monitoring wells. During
construction these will serve to detect changes in die migration of the contaminated plume and
indicate effectiveness of remedial actions. At that time, a sampling and chemical analysis plan
will be implemented. Groundwater monitoring will continue for a minimum of 5 years and
could be extended upon die occurrence of certain events, including but not limited to: analytical
data indicating an increase in the levels of contamination in the shallow groundwater; or
analytical data indicating significant fluctuations in contaminant levels between sampling events.
The number and location of groundwater monitoring wells and die frequency and analysis will be
established in the remedial design work plan.
11.0 STATUTORY DETERMINATION
Under its legal audiority, EPA'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 establishes several other statutory requirements and preferences. These
specify that when complete, the selected remedial action for the site must comply with ARARs
unless a statutory waiver is justified. The selected remedial action must also be cost-effective and
utilize permanent solutions and alternative treatment technologies or resource recovery
technologies to the maximum extent practicable. Finally, the statute includes a preference of
remedies that employ treatments that permanendy and significandy reduce the volume, toxicity,
or mobility of the hazardous waste as dieir principal element.
The following subsections discuss how die selected remedy for die Quality Plating site meets
these statutory requirements of Section 121 of CERCLA, as amended by SARA, and to the
maximum extent possible, the NCP.
11.1 PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
The selected remedy protects human health and the environment by reducing hexavalent
chromium to a less toxic form, trivalent chromium. Nearly 90% of the chromium will be
removed as a precipitate with die sludge being characterized and properly disposed of off-site in
an EPA approved facility.
Removal and treatment of die contaminated groundwater will eliminate die threat of exposure to
the contaminate of concern. Implementation of the selected remedy will not pose any
unacceptable short-term risks or cross-medial impacts such as airborne toxics or exposure to water
to the site, the workers, or the community.
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11.2 COMPLIANCE WITH ARARs
The selected remedy will comply with all applicable, relevant, and appropriate requirements. No
waiver of an ARAR is being sought or invoked for the selected remedy. The ARARs of concern
include but are not limited to the following:
11.2.1 LOCATION-SPECIFIC ARARs
Action-specific ARARs are technology or activity based requirements of limitations on actions
affecting hazardous wastes. These requirements are triggered by the particular remedial activities
selected to cleanup the site. Action-specific ARARs include the following:
Clean Water Act
DOT Hazardous Materials Transportation Act
Missouri Solid Waste Law and Rules
Missouri Hazardous Waste Management Law and Rules
Missouri Hazardous Substance Rules
Missouri Clean Water Law
Missouri Water Quality Standards
Missouri Water Pollution Control Rules
Missouri Solid Waste Disposal Act
Occupational Safety and Health Act
11.2.2 CHEMICAL-SPECIFIC ARARs
Chemical-specific requirements are usually health or risk based numerical values or methodologies
that establish the acceptable amount or concentration of a chemical in the ambient environment.
The following are the chemical-specific requirements for Quality Plating:
Clean Water Law
Missouri Clean Water Law
Missouri Water Pollution Control Rules
National Pollution Discharge Elimination System
National Primary Drinking Water Standards
Safe Drinking Water Act
11.2.3 LOCATION-SPECIFIC ARARs
The Illinois chorus frog, (Pseudacris streckeri illinoenis). which has a state listing as "rare", and
the umbrella sedge (Cyperus grayioides) which is a state listed endangered plant species, have both
been identified near the site; therefore, the Endangered Species Act is a location-specific ARAR,
11.2.4 TO BE CONSIDERED
A memorandum from the MDOH provided PRGs for the Quality Plating site. The PRGs are
TBCs and will be considered as an ARAR. The PRGs are found on Table 7.
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11.3 COST-EFFECTIVENESS
The selected alternative is cost-effective because it has been determined to provide overall
effectiveness proportional to its cost, estimated at a present total worth of $1,166,000. While
Alternative 6 has a lower cost than the selected alternative, it will require 5-6 years of additional
remediation to meet the PRGs. During this time short-term risks during O&M and the
possibility of exposure to area residents would be increased. The selected alternative assures a
higher degree of overall protection than the least cosdy alternative (Alternative 4).
11.4 UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE
TREATMENT OR RESOURCE RECOVERY TECHNOLOGIES TO THE MAXIMUM
EXTENT PRACTICABLE
The selected remedy represents the maximum extent to which permanent solutions and treatment
technologies can be utilized at the Quality Plating site to meet water quality requirements. Of
those alternatives that are protective of human health and the environment and comply with
ARARs, EPA has determined that this selected remedy provides the best balance of tradeoffs in
terms of long-term effectiveness and permanence; reduction in toxicity, mobility, or volume
achieved through treatment; short-term effectiveness; implementability; and cost.
11.5 PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
The selected remedy satisfies, in part, the statutory preference for treatment as a principal
element. The principal threat to human health is from ingestion or dermal contact with
contaminated groundwater. Hexavalent chromium will be reduced to a less toxic form, trivalent
chromium through the treatment process chemical reduction. Trivalent chromium will be
removed as a precipitate with die sludge being characterized and properly disposed of off-site in
an EPA approved facility.
12.0 DOCUMENTATION OF SIGNIFICANT CHANGES
The Proposed Plan for the Quality Plating site, which identified Alternative 3 as the preferred
remedy, was released for public comment on September 11, 1994. One written comment was
received in addition to the oral comments received during die public meeting held on October 3,
1994 and is addressed in die attached Responsiveness Summary. Upon review of these
comments, it was determined diat no significant changes to die remedy, as it was identified in the
Proposed Plan, were necessary.
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QUALITY PLATING SITE
RESPONSIVENESS SUMMARY
TABLE OF CONTENTS
Community Relations History Page 1
Overview Page 2
Summary of Public Comments Received Page 3
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QUALITY PLATING SITE RESPONSIVENESS SUMMARY
Community Relations History
Comprehensive Environmental Response, Compensation, and Liability Act of 1980 (CERCLA)
requirements for public participation include releasing the Feasibility Study (FS) and the Proposed
Plan to the public and providing a public comment on the Feasibility Plan and Proposed Plan.
The Department of Natural Resources (DNR) met these requirements in September 1994 by
placing both documents in the Administrative Record for the site. DNR published a notice of
the release of the FS and Proposed Plan in the Sikeston Standard Democrat on September 11
and 28, 1994 and October 2, 1994. Notice of the 30 day public comment period and the public
meeting discussing the Plan were included in the newspaper notice. A public meeting was held
on October 3, 1994 at the Ramada Inn in Miner, Missouri. The public comment period was
extended an additional 30 days and ended on November 10, 1994 with one letter received from
the public
To date, the following community relations activities have been conducted by DNR at the
Quality Plating site:
October 30, 1991 An availability session was held in which an information exchange
between area residents and department personnel took place.
August 11, 1992 A public meeting was held with questions centering around the
health aspects associated with the site, private water testing, and
CERCLA enforcement actions.
December 8, 1992 A community meeting was held at the Sandywood Baptist Church
to answers questions of the area residents.
September 30, 1993 A public meeting was held to present the Federal Investigation of
Groundwater (FIG) to concerned citizens and to discuss future
activities.
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September 9, 1994 The Administrative Record containing the FS and the Proposed
Plan is in place.
September 11, 1994 A public notice announces the release of the FS and Proposed Plan
for public comment and announces the public comment period
(the notice was also printed on September 28 and October 2,
1994).
October 3, 1994 A public meeting is held to receive public comment on the FS and
Proposed Plan (approximately 22 people are in attendance, of
which, about 12 people represented area citizens). The public
seemed to be in general agreement of the preferred remedy.
October 9, 1994 A public notice announces that the public comment period is
extended an additional 30 days.
November 10, 1994 The public comment period is closed with one letter from the
public received.
November 1994 Responsiveness Summary prepared.
Overview
In the Proposed Plan released to the public, the MDNR, with concurrance from the
Envirnomental Protection Agency (EPA), made a preliminary selection of the preferred remedy.
The MDNR's recommended alternative addressed contaminated groundwater at the site. The
preferred alternative involved a pump and treat system using reduction\precipitation. The treated
effluent from the treatment process will be pumped and discharged to Ditch No. 4.
The comments received from interested citizens during the public meeting focused on potential
health issues during the remedial action, the continued testing of private drinking wells in the
immediate area, the receiving stream, and the schedule for implementation of the alternative.
The area residents generally accepted the preferred remedy.
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Comments received during the public meeting and the written comment received are summarized
as follows:
Comment #1
A commentor requested a 30 day extension to the public comment period.
Response - An extension to the public period comment period was granted and the
comment period was extended 30 days to November 10, 1994.
Comment #2
A commentor asked the Missouri Department of Health (MDOH) to explain from page 5
of the Proposed Plan "Consequently, non-carcinogenic health risks may be present for
future adults or a child residing or living on the site".
Response - The site risk assessment was explained in which the most contaminated sample
of water was used (1,206 mg/L of hexavalent chromium sampled from pushin well screen
number HP-4) and based on this, if an adult drank this water or bathed in this water for
30 years or if a child drank this water or bathed in this water for 6 years there may be a
non-carcinogenic health risk for those living on this site. Non-carcinogenic risks are non-
cancer causing risks and include such effects as stomach pains and cramps, gastric ulcers,
skin irritation, and dermatitis.
Comment #3
A commentor asked if the risk was limited to one living only on this site.
Response - Yes, the risk as explained in the risk assessment is limited to persons living
only on this site.
Comment #4
A commentor asked how long the biannual water testing of private wells would continue.
Response - Biannual testing will continue through the 5 year review period. If there is a
potential problem noted at that time the testing will be continued.
Comment #5
A commentor asked why Alternative 3 was selected as the preferred remedy over
Alternative 7.
Response - Alternative 3 was selected because, while both will meet the Preliminary
Remediation Goals (PRG) for hexavalent chromium of .018 mg/L, meet effluent
requirements for chromium of .280 mg/L, and remediate the site in two years, Alternative
3 can be constructed with an approximate savings in capital costs of $215,000 and
$40,000 in annual operation and maintenance costs.
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Comment #6
A commentor indicated that some confusion may be coming from the discussion of ppb
and ppm and ask that we go through the requirements we are seeking to achieve.
Response - The PRG for hexavalent chromium is 0.018 mg/L. This is equal to .018 ppm
or 18 ppb. Our effluent limit proposed by the "Water Pollution Control Program
(WPCP) for chromium is .280 mg/L. This is equal to .280 ppm or 280 ppb. The most
contaminated sample of groundwater taken was approximately 1.400 ppm. All indications
point to a reduction with the selected treatment process of approximately 90%. If even
the most contaminated water was being treated, one could expect the treatment system to
produce an effluent of approximately .140 ppm (1.400 X 90%). Additional satisfaction
can be arrived in knowing diat the effluent limit is based on hexavalent chromium, which
is very toxic, and the effluent produced by the treatment system will be the less toxic
trivalent form.
Comment #7
A commentor asked if the effluent limit of .280 ppm was for total chromium.
Response - While the number provided by the WPCP is stated for Chromium it is based
as if all the chromium were hexavalent chromium.
Comment #8
One commentor asked if there is a lung cancer risk from hexavalent chromium.
Response - There is a cancer risk for inhaling the dust only.
Comment #9
One commentor asked what the radius was of the contaminated water at the site.
Response - The plume is approximately 500 feet by 300 feet and extends about 200 feet
to the south of the property.
Comment #10
One commentor asked what did she need to be concerned with living next to the site.
Response - Again, it was reiterated that the risks would be a result of actually drinking the
contaminated water or bathing in it. Area private wells are to be tested biannually and
previous test results indicated the private wells are free of contamination.
Comment #11
One commentor responded that it appeared then that there would be very little public
input.
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Response - There will be given substantial consideration given to all public input received,
not only to the public input received during the meeting, but to any written comments
received during the remaining public comment period.
Comment #12
One commentor asked if they were under any legal requirement to disclose that they lived
near this site if they chose to sell their property.
Response - The state's registry system for abandoned and uncontrolled hazardous waste
sites was explained and that owners of properties on the registry must notify potential
buyers that the site is on the registry; however, it was stated that the Quality Plating site
is not on the registry and property owners are not required to notify buyers.
Comment #13
One commentor asked if the risk assessment was based on old samples.
Response - After a removal action was conducted to eliminate risk from soils, a second
risk assessment was prepared to address potential risks resulting from the remaining
contaminated groundwater. This second risk assessment was based on the more recent
samples taken after the removal action.
Comment #14
A commentor asked what responsibility does the Quality Plating company have for paying
for the cleanup.
Response - They are responsible but they have gone bankrupt and do not have any assets.
Comment #15
A commentor asked if the present landowner, even if he did not do the dumping himself,
could be made to clean up the property.
Response - The law clearly states that the property owner is liable. That is not to say that
EPA will go back and recover the cleanup costs from the landowner but the law allows for
that.
Comment #16
A commentor indicated that Ditch No. 4 (the proposed receiving stream for the treated
effluent) was privately owned.
Response - Ditch No. 4 is a classified stream and as such is recognized as waters of the
State of Missouri.
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Comment #17
One commentor asked if there was any possibility of contaminating the Mini Farms
during spring floods with the discharge.
Response - There is no possibility of contaminating die Mini Farms property widi effluent
from this treatment process. Water being discharged will meet the effluent limits for this
receiving stream. This limit is based on the beneficial uses of the stream and the
chromium limit is 280 ppb. This limit is based as if all the chromium will be of the
toxic hexavalent form; however, not only will the effluent meet the discharge
requirements, any chromium in the treated effluent will be of a much less toxic trivalent
form.
Comment #18
One commentor indicated he understood that the treated discharge would be drinking
water quality.
Response - While the treated effluent will meet all requirements it has never been claimed
to be drinking water quality. While it is the PRG (18 ppb for hexavalent chromium) to
treat the contaminated plume to drinking water quality, the discharge requirement for the
effluent is 280 ppb.
Comment #19
One commentor asked what will happen to animals and fish diat drink water in the
receiving stream and will it be safe for diem.
Response - The Missouri Water Quality Standards which establish the effluent limits for
die receiving stream are based on die beneficial uses of the stream. Livestock and wildlife
watering and warm-water fisheries are recognized as beneficial uses of Ditch No. 4 and, as
such, the effluent limit is protective for these uses.
Comment #20
One commentor asked how they could get comments recognized after die meeting closed.
Response - It was repeated that die public comment period would be extended and die
name and address as to where written comments could be sent was provided.
Comment #21
One commentor asked that of the seven alternatives, who would decide on which
alternative eventually gets selected.
Response - The MDNR will consider all die public comments received on die Proposed
Plan during the public comments period, both written and oral, and with consultation
widi the EPA will select die remedy and write die Record Of Decision (ROD). The
ROD will be reviewed and approved by the department's Hazardous Waste Program
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(HWP), the Division of Environmental Quality (DEQ), and the Director of DNR. After
receiving these approvals the ROD will be sent to EPA where it will be further reviewed
and finally signed by Mr. Dennis Grams, the Regional Director. A notice would be
published in the newspaper when the ROD was available.
Comment #22
One commentor asked that after getting the final signature on the ROD, how long before
the actual cleanup operation is started.
Response - It is planned that design services can be procured by the first of March and
die facility can be under operation by March, 1996.
Comment #23
One commentor asked if there was enough opposition to "running the waste down the St.
John's Ditch", would that have any input into your decision on how you are going to
dean it up.
Response - If there were opposition, attention would first be given to what objections
were being made and why. We would also look at what other alternatives were available
and what compromises, if any, could be made. While the first priority is to protect
human health and the environment, considerable effort will be given to achieving
community agreement with the selected alternative.
Written comments received
A single written comment was received. The commentor indicated agreement with
Alternative 3 (the preferred remedy) and stated the commentor was convinced this is the
safest and best alternative. An appreciation was also expressed for extending die public
comment period.
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