United States         Office of
        Environmental Protection    Emergency and
        Agency            Remedial Response
EPA/ROD/R04-91 /080
December 1990
EPA   Superfund
        Record of Decision
        Monsanto, GA

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50272-101
I REPORT DOCUMENTATION 1" REPORT NO.       I ~      3. Recipient. Acc888ion No.  
 PAGE      EPA/ROD/R04-91/080             
TI1I8 and Sublile                       5. A8par1 Date    
SUPERFUND RECORD OF DECISION                 12/07/90 
Monsanto, GA                   6.       
First Remedial Action - Final                     
7. Author(.)                       8. P8rfannlng Organlzallan Rept. No'
8. P8rfannlng Orllalnlzallan NanI8 and Add/'888                 10. PrajectlTuklWork Unh No.  
                        11. ContraC1(C) or Grant{G) No.  
                        (C)       
                        (G)       
1~ SporworIng Orllanlza1lon NanI8 and Addre88                 13. Type af Report & P8r1ocf Covered 
U.S. Environmental Protection Agency                 
401 M Street, S.W.                    800/000  
Washington, D.C. 20460                14.       
15. Supplementary Na..                            
16. Ab81rac1 (UmI1: 200 worda)                          
The 75-acre Monsanto site is a former industrial plant located three miles southeast
of Augusta, Georgia. Land use in  the area is predominantly industrial, with a wetland
area located approximately 4,570 feet from the site. In addition, the site is 
approximately three miles from the Savannah River, an important source of water for
the Augusta area. The plant began operations in 1962. From 1966 to 1974,  
approximately 1500 pounds of arsenic were placed in two on site  landfills. The 
landfills were covered with soil,  crowned with gravel, seeded with grass, and closed
in 1971 and 1977, respectively. Ground water investigations conducted in 1979 and
1980 by Monsanto identified arsenic in the surficial aquifer in excess of the Federal
MCL. In 1983, Monsanto, through a State action, excavated the materials in the 
landfills and disposed of them offsite. Soil samples collected from the bottom of the
excavated area did not exceed the EP toxicity standard for arsenic. This final Record
of Decision (ROD) addresses ground water.contaminat~o~. The primary contaminant of
concern affecting the ground water is arsenic, a metal.          
(See Attached Page)                        
17. Document Analyala L Descrlplora                          
Record of Decision - Monsanto, GA                  
First Remedial Action - Final                    
Contaminated Medium: gw                       
Key Contaminant: metals (arsenic)                  
b. ldenlilier./Open-Ended Terma                          
Co COSA TI FIeIdIGroup                            
18. Availability Statement               18. Security CI... (Thi. Report)    21. No. af Pagea
                      None       58
                  20. Security CI... (Thl. Page)    22. PrIce  
.                      None        
                              . fORM 212 (4-77)
(See ANSl-Z39.18)
See InalrUCliana on Reve-
(Fonnet1y NT1~)
Department a' Commerce

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EPA/ROD/R04-91/080
Monsanto, GA
~irst Remedial Action - Final
Abstract (Continued)
The selected remedial action for this site includes monitoring ground water to evaluate
compliance with Ground Water Protection Achievement Levels (GPALs); pumping and
discharging ground water to an offsite publicly owned treatment works (POTW), in the
event that non-compliance with GPALs occurs; monitoring ground water for two years
following EPA's acceptance that the MCL has been attained. The estimated present worth
cost for this remedial action is $600,000.
PERFORMANCE STANDARDS OR GOALS: The chemical-specific and GPAL ground water cleanup goal
for arsenic is 0.05 mg/l based on SDWA MCLs.

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REGION IV
34:: CCU::
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                 DECLARATION FOR THE  RECORD OF DECISION


Site Name and Location:

Monsanto Superfund Site - Augusta, Georgia


Statement of Basis and Purpose;

This decision document presents the selected remedial action for the
Monsanto Superfund site in Augusta/ Georgia, developed in accordance
with the Comprehensive Environmental Response, Compensation and
Liability Act of 1980 (CERCLA), as amended by the Superfund Amendment
and Reauthorization Act of 1986  (SARA), and to the extent
practicable, the National Contingency Plan (NCP), March 8, 1990.  The
selection of the remedial action presented in this document is based
on the administrative record for the Monsanto site.  The attached
index identifies the items that comprise the administrative record
(Appendix A).

The State of Georgia has concurred on the selected remedy.


Assessment of the Site;

Actual or threatened releases of hazardous substances from this site,
if not addressed by implementing the response action selected in this
Record of Decision (ROD), may present an imminent: and substantial
endangerment to public health, welfare, or the environment.


Description of the Selected Remedy:

Upon review of the information contained in the administrative
record, it is EPA's judgment that the selected remedy best serves the
selection criteria in CERCLA and the NCP in relation to the other
options evaluated.  A detailed description of this groundwater remedy
and an explanation of how it meets statutory requirements is
contained in the attached "Summary of Remedial Alternative
Selection".

The major components of the selected remedy include:

         * Continue quarterly groundwater monitoring during the
           design of the selected remedy to determine compliance with
           the Groundwater Protection Achievement Levels  (GPALs);

         * Should the annual average of the levels as determined by
           the quarterly monitoring exceed the GPALs, extraction of
           groundwater which exceeds the Primary Drinking Water
           Standard for arsenic will commence;

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2
. Discharge extracted groundwater for treatment at a
Publicly Owned Treatment Works (POTW);

. Groundwater monitoring for a minimum of two (2)
years following the achievement of the Maximum Contaminant
Level ( MCL) .
Declaration:
The selected remedy is protective of human health and the
environment, attains Federal and State requirements that are
applicable or relevant and appropriate to the remedial action, and is
cost effective. The remedy satisfies the statutory preference for
remedies that employ treatment as a principal element to reduce
toxicity, mobility, or volume and utilizes permanent solutions and
alternative treatment (or resource recovery) technologies to the
maximum extent practicable. Because this remedy will not result in
hazardous substances remaining onsite above drinking water criteria,
the five-year review will not apply to this action.
~ 7, /CJ9(
DATE '
,J~tn~
~ Greer C. Tidwell
7 Regional Administrator
'0 .

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RECORD OF DECISION
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
MONSANTO SUPERFUND SITE
AUGUSTA, GEORGIA
", .
Prepared byz
U.S. Environmental Protection Agency
Region IV
Atlanta, Georgia

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                           TABLE OF CONTENTS
1.0  Site Location and Description	   1

2.0  Site History and Enforcement 	   1

3.0  Highlights of Community Participation 	   3

4.0  Scope of Remedial Action 	   4

5.0  Site Characteristics  	   4
     5.1  Geology 	   4
     5.2  Hydrogeology 	   6
     5.3  Surface Water  	   6
     5.4  Sampling Results 	   6

6.0  Summary of Site Risks 	  10
     6.1  Identification of the Contaminant of Concern 	  14
     6.2  Exposure Assessment Summary 	  14
     6.3  Toxicity Assessment Summary	  15
     6.4  Risk Characterization Summary 	  15
     6.5  Environmental Risk Summary 	  17

7.0  Description of Alternatives 	  17
     7.1  Alternative 1 - No Action 	  17
     7.2  Alternative 2 - Establish an Alternate
                          Concentration Limit 	  18
     7.3  Alternative 3 - Pump and Discharge 	  18
     7.4  Alternative 4 - Pump and Treat Onsite 	  19

8.0  Summary of Comparative Analysis of Alternatives 	  21
     8.1  Overall Protection of Human Health
          and the Environment 	  21
     8.2  Compliance with Applicable or Relevant
          and Appropriate Requirements 	  23
     8.3  Short Term Effectiveness 	  23
     8.4  Long Term Effectiveness 	  23
     8.5  Reduction of Mobility, Toxicity or
          Volume Through Treatment 	  23
     8.6  Implementability 	  24
     8.7  Cost 	  24
     8 .-8  Community Acceptance 	  24
     8.9  State Acceptance 	  25

9.0  Selected Remedy 	 25

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                     Table of Contents (continued)


10.0 Statutory Determinations 	  26
     10.1 Protection of Human Health and
          the Environment 	  26
     10.2 Attainment of Applicable or Relevant
          and Appropriate Requirements 	  26
     10.3 Cost Effectiveness 	  27
     10.4 Utilization of Permanent Solutions and
          Alternative Treatment Technologies 	  27
     10.5 Preference for Treatment as a Principal Element 	  27

11.0 Documentation of Significant Changes 	  27

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                            LIST OF FIGURES





                                                                 PAGE



Figure 1  Site Location Map	   2



Figure 2  Geologic Cross Section 	   5



Figure 3  Generalized Stratagraphic Section 	   7



Figure 4  Monitoring Well Locations 	  11



Figure 5  Plume Boundary	  12



Figure 6  Predicted Plume Migration 	  13





                            LIST OF TABLES





                                                                 PAGE



Table 1   Arsenic Concentrations in Sampled Media  	   8



Table 2   Analytical Data Summary, June 1990  	   9



Table 3   Projected Arsenic Concentration  (MW-35)  	  16



Table 4   Groundwater Protection Achievement  Levels  	  20



Table 5   Glossary of Evaluation Criteria  	  22

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                Summary of Remedial Alternative Selection
                        Monsanto Superfund Site


 1.0   SITE  LOCATION AND DESCRIPTION

 The  Monsanto  Superfund site is located approximately three miles
 southeast  of  Augusta, Georgia.  The site is bordered on the north by
 Marvin  Griffin  Road, on the east by the Norfolk and Southern
 Railroad,  on  the south by Butler Creek and on the west by other
 industrial properties (Figure 1).  Phinizy Swamp is located
 approximately 4,570 feet northeast of the site.  The Monsanto plant
 covers  approximately 75 acres.  Within the plant's boundary, two
 landfills  covering 0.2 acres that were used to dispose of phosphoric
 acid sludge.  The landfills are located along the eastern boundary of
 the  Monsanto  plant property.

 The  site is located in an industrial park which is zoned for heavy
 industrial use.  Within a three mile radius of the site, land is
 zoned commercial, residential and industrial.  The nearest
 residential area is one-half mile northwest of the site.  Surface
 elevations across the site range from 140 to 146 feet above Mean Sea
 Level (MSL).


 2.0   SITE  HISTORY AND ENFORCEMENT

 The  Monsanto-Augusta Plant has been in operation since 1962.  From
 1966  to 1974, two landfills (0.1 acre each), approximately six feet
 deep, were used to dispose of solid waste and sludges which contain
 arsenic trisulfide.  Arsenic trisulfide is a waste resulting from the
 preparation of  food grade phosphoric acid.  Plant officials estimate
 approximately 1500 pounds of arsenic were placed in these landfills.
 In 1971, Landfill fl was covered with soil, crowned with gravel and
 seeded with grass.  In 1977, Landfill #2 was closed by Monsanto in
 the  same manner as Landfill fl.

 The  site was  first identified by the Georgia Environmental Protection
 Division (EPD)  in August 1975.  In June 1979, Monsanto, under the
 supervision of  the EPD, began monitoring the quality of the
 groundwater south of the site.  In February 1980, at the request of
 EPD, Monsanto installed additional monitoring wells and collected
 twenty-three  soil samples on the site.  The groundwater monitoring
program revealed arsenic levels in the surficial aquifer exceeding
 the Federally regulated drinking water standard  (i.e. Maximum
Contaminant Level or MCL) for arsenic of 0.05 mg/1.

During November 1983, Monsanto, under the supervision of EPD,
excavated  the waste from both of the landfills.  The material
excavated  from  the landfills was transported to  a RCRA permitted
landfill in Emelle, Alabama.  After the contents of the landfills
were removed, soil samples were collected from the bottom of the

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GEORGIA
FIGURE
SITE LOCATION MAP
1
MONSANTO SITE
AUGUSTA, GEORGIA

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3
excavated area and tested for Extraction Procedure (EP) toxicity for
arsenic and other metals. EP toxicity is a test used to identify
wastes that are likely to leach hazardous concentrations of toxic
substances and to determine if a contaminant is a characteristic
hazardous waste. The soil from the bottom of the excavated area did
not exceed the EP toxicity standard for arsenic of 5.0 ppm.

In September 1984, the Monsanto site was added to the National
Priority List (NPL). The NPL comprises hazardous waste sites which
appear to present a significant risk to human health or the
environment. Sites are placed on the NPL if they have a ranking
score of 28.50 or greater. The Monsanto site was ranked at 35.65.
On January 18, 1989, EPA issued a special notice letter to Monsanto
to give Monsanto the opportunity to conduct, with BPA oversight, the
Remedial Investigation (RI) and Feasibility Study (FS). Monsanto
entered into an Administrative Order on Consent for performance of
the RIfFS, with an effective date of April 27, 1989.

Fieldwork for the RI was initiated by Monsanto in October 1989 and
completed in January 1990. The final RI report was accepted by BPA
on August 20, 1990. The FS report was submitted to EPA by Monsanto
on September 16, 1990.
EPA will continue its enforcement activities and will send a Special
Notice Letter to Monsanto prior to the initiation of the remedial
design for the selected remedial action. Should Monsanto decline to
conduct future remedial activities, BPA will either take additional
enforcement actions or provide funding for these activities while
seeking cost recovery for all BPA-funded response actions at this
site.
3.0
HIGHLIGHTS OF COMMUNITY PARTICIPATION
A Community Relations Plan was prepared by BPA in December 1988. In
October 1989, JPA printed and distributed a fact sheet describing the
activities to be conducted during the RI and FS. An informal meeting
was held by BPA on October 20, 1989, to address concerns the public
may have had regarding the site investigation.

The Proposed Plan for the Monsanto Superfund site was released to the
public on October 30, 1990. The administrative record, which
contains documents relating to the remedy selection at the site,
including the RIfFS Reports and the Proposed Plan, was made available
to the public at the Region IV BPA Office in Atlanta, Georgia and the
Augusta-Richmond County Library in Augusta, Georgia. The notice of
. .,~
.".' ..........,....,.
-".-' .,...~ ,-,,.,,,

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4
availability of the 'administrative record was published in the
Auausta Chronicle and Herald on November 1, 1990. A public comment
period was held from November 1, 1990 to November 30, 1990. In
addition, a public meeting was held on November 14, 1990 at the
Augusta - Richmond County Library. At this meeting, representatives
from EPA and the State of Georgia Environmental Protection Division
answered questions about the facts surrounding the site. A response
to the comments received during this period is included in the
Responsiveness Summary, which is part of this Record of Decision
(Appendix B). This decision document presents the selected remedy
for the Monsanto Superfund site in Augusta, Georgia, chosen in
accordance with CERCLA, as amended by SARA, and to the extent
practicable, the NCP. The decision for this site is based on the
administrative record.
4.0
SCOPE OF REMEDIAL ACTION
This is the first and final planned remedial action for this site.
The remedial action selected at this site would protect human health
and the environment from potential exposure to the arsenic
contaminated groundwater in the surficial aquifer. The objectives
for the remedy are to minimize the migration of contamination from
the onsite landfills towards Phinizy Swamp and the underlying
Cretaceous aquifer (also known as the Tuscaloosa aquifer), as well as
to restore the groundwater in the surficial aquifer to drinking water
quality for arsenic.

Following the attainment of the drinking water standard, groundwater
monitoring will continue for a minimum of two years. Should this
monitoring detect elevated contaminant levels from the Monsanto site,
EPA will evaluate the need for additional remedial action. In
addition, EPA will re-evaluate the effectiveness of this remedy
should the drinking water standard for arsenic be revised.
5.0
5.1
SITE CHARACTERISTICS
GEOLOGY
The Monsanto site is located just south of the Fall Line in the
Atlantic Plain Major Division, Coastal Plain physiographic province.
The site is underlain by recent alluvium and Cretaceous sediments.
The alluvium deposits consist of sand and gravel to clay and sandy
clay. Underlying the alluvium and outcropping in parts of the site
area is the Cretaceous age Gaillard Formation (Figure 2). The
Gaillard Formation is composed of interbedded sand, gravel and clay
layers.
""''''... ,,-,,-"''''',,- '. .""...'

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6
5.2
HYDROGEOLOGY
Two distinct water bearing zones are present beneath the Monsanto
site. A surficial aquifer which occurs in the alluvium deposits and
the Cretaceous aquifer which occurs in the Gaillard Formation. The
surficial aquifer extends from the surface to a depth of 70 feet.
The saturated thickness of this aquifer is approximately 50 feet.
The surficial aquifer is separated from the underlying Cretaceous
aquifer by a 40 foot layer of clay. The Cretaceous aquifer has an
average thickness of 110 feet and extends from beneath the 40 foot
thick confining clay layer to bedrock (Figure 3).
Groundwater in the surficial aquifer moves in an easternly direction
towards Phinizy Swamp, located one mile from the site, at a rate of
0.9 feet per day. The transmissivity of this shallow water bearing
zone is 10,750 gallons per day per foot. In the underlying
Cretaceous aquifer, groundwater also flows in an easterly direction.
The transmissivity of this zone is significantly greater than the
surficial aquifer (17,000 to 130,000 gallons per day per foot);
therefore, most wells in the area are developed in this deeper zone.
There are no known downgradient wells in the surficial aquifer being
used as drinking water sources within a one mile radius from the
site.
5.3
SURFACE WATER
The two main bodies of surface water which are proximate to the
Monsanto Superfund site are Butler Creek and Phinizy Swamp. Butler
Creek, southeast of the site, marks the southern boundary of the
Monsanto plant property. The creek is used for fishing; however, it
is not a source of drinking water. Butler Creek, after accepting the
City of Augusta Publicly Owned Treatment Works (POTW) outfall, flows
through the southwest edge of Phinizy Swamp and finally into the
Savannah River approximately three miles southeast of the site. The
Savannah River is an tmportant source of water and transportation for
the Augusta area.
5.4
SAMPLING iU:SULTS
The primary emphasis for analytical testing during the RI was placed
on determining the impact the two onsite landfills may have had on
the environment at the site, including the effect on soil, surface
water, sediment, air, and groundwater. Specifically, the analytical
testing program was developed to detect the presence of arsenic. A
summary of the arsenic levels detected for each media sampled in the
RI is provided on Table 1. A supplemental sampling effort was
conducted by EPA in June 1990 to determine whether other contaminants
were present in soils and the groundwater. The results of the June
1990 sampling effort are presented on Table 2.

Eighteen surficial soil samples were collected on the Monsanto
property as well as on the adjacent property towards the east during

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o feet
20 feet
70 feet
110 feet
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7
FIGURE 3 .
GENERALIZED STRATAGRAPHIC SECTION
Monsanto Superfund Site
Augusta, Georgia
"7
SGRFICIAL AQUIFER
(ALLGvrC'!)
AQUITARD
. .
LOWER AQUIFER
(CRETACEOUS GAILLARD FO~~TION)
(CRYSTALLI~E BASE~ENT)
S.:nd a::(
Sandy Clays
Clay
Sand and
Gravel
3t2C::-2~~
....'

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                                TABLE 1
                ARSENIC CONCENTRATIONS IN SAMPLED MEDIA
MEDIA NUMBER OF
SAMPLED SAMPLES
SOILS 43
(mg/kg)
ARSENIC BACKGROUND
CONCENTRATIONS CONCENTRATIONS
<0.75<1) - 8.9 2.6
10.7
(mean)
(max) l*J
SURFACE WATER
  (ug/1)
                   8
  SEDIMENT
  (mg/kg)
                  23
  <0.99(1)
5 - 4,000(3)
RUNOFF WATER
  (ug/1)
    AIR
  (ug/mj)
                  20
<2.85xlO~4(1)
   2xlO
                                                          -3
 GROUNDWATER
   (ug/1)
                  40
    5 -
(1) Limit of Detection
(2) Carey/Wiersma, 1972
(3) Wilson/Hawkins, 1978
(4) Avg. 24-hr. Ambient Air Arsenic Levels, U.S. National Academy of
    Sciences (NAS 1977)
(5) Remedial Investigation, 1990

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I~ORG~;rC ELE.'-~E~TS
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BARIUM
BERYLLIl:!
CADXIt'M
CH...~O~IUX
CCSAL!
COPPER
LEAD
x..':'.NGANES E
MERCURY
NICKEL
STRONTIUX
TITA.~IUM
VA.~ADIUX
YTTRIUX
ZINC
CALClt'M
IRON
M.:\GNES It"X
SODIt..'M
POTASSIUM
CYA.';IDE
EXTRACTABLE ORG~HCS
3 CNIDENTIFIED CO~POu~DS
?ETROLEt"X PRODUCTS
BCTYLIDENEBIS~DIMETHYt-
ETHYt)MEIHYLPH~~OL
VOLATILE ORGANICS
PESTICIDES/PCB's
Foo::note:
- Material anayzed for
N . Pres~~ptive evidence
J - Esti~ated value
-."_-"_'>"~"""'-"-~".
." .. .."." . ...-
9
TA3LE 2
A.\'ALYTICAL DATA St.-:!..'-L.:..RY
MONS~;TO NFL SITE
AUGCSTA, GEORGIA
JL~E. 1990
SB-01
SOIL
mg!kg

11000
3.4
62
36
6.0
3.8
15
29
130
34
2.5
6.4
mg/kg
150
18000
140
/Jg!kg
SB.02
SOIL
mg/kg
12000
4.9
46
0.50
11
80
1.2
3.5
7.4
73
0.12
5.4
20
1000
33
9.1
25
mg!kg

1200
6500
710
3900
240
/Jg!kg
7000JN
but not detected
of prsence of material
M'J-17
t.:ATER
JJg/l

8500
69
14
18
15
68
180
60
mg/1

2.0
4.8
0.31
190
/Jg/l
N
M'J.35
~.A:::R
JJg/l
21COO
80
, ~
.0
33
15
1i
21
160
430
17
18
mg/l
2.8
12
0.':'':'
300
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                                   10

 the  RI.  Subsurface  soil borings were also collected to depths of
 thirty six  feet at ten locations.  A supplemental sampling effort,
 conducted by EPA in  June 1990, served to collect subsurface soil
 samples  from Landfill f2 at 6 foot and 8.5 foot depths.  The RI
 samples  were analyzed for arsenic and were found to be at either near
 background  or nondetectable levels.  Samples collected during the
 June 1990 sampling effort were analyzed for the Target Compound List
 parameters.  The results of the June 1990 sampling effort did not
 indicate elevated contaminant levels.  Based on the soil data
 collected during the RI and the June 1990 field effort, further soil
 remediation is not necessary.

 Surface  water and stream sediment samples were collected from six
 locations along Butler Creek.  In addition, storm water runoff was
 collected from the site at five locations.  None of the samples
 collected during the RI showed arsenic levels above the detection
 limit.

 Air  monitoring conducted onsite during the installation of several
 monitoring  wells during the RI did not indicate a threat to human
 health or the environment.  Analysis of an air monitoring station
 sample did  not indicate arsenic levels above the analytical detection
 limit.

 Thirty-nine wells have been installed at the site in the surficial
 aquifer  to  determine the extent of arsenic contamination.  Well
 locations are shown  on Figure 4.  Of the wells sampled, only two
 exceeded the Federally regulated drinking water standard (ie., MCL)
 for  arsenic of 0.05  mg/1 during the RI.  The arsenic concentrations
 observed that exceeded the MCL were 0.06 mg/1 and 0.085 mg/1 in
 monitoring  wells MW-17 and MW-35, respectively, both of which are in
 the  surficial aquifer.  Figure 5 depicts the estimated extent of
 arsenic  contamination in the surficial aquifer which exceeds the
 current  drinking water standard.  The volume of arsenic contaminated
 groundwater is estimated to be 7.7 million gallons.

 The  results of the sampling effort during the RI, along with
 hydrogeologic^parameters developed from pumping tests and slug tests
were used to predict future arsenic levels within the surficial
 aquifer.  To project future movement of the arsenic plume, a model
was developed.  The  modeling indicates the arsenic plume is moving
downgradient towards Phinizy Swamp at a flow rate of 0.3 feet per
day.  As shown in Figure 6, the modeled core of the plume is expected
to dissipate to below drinking water standards by the year  1995.
Within ten  years, the model predicts the plume will have diminished
to background.  Based on the model, there will be no site related
discharge of the arsenic contamination into Phinizy Swamp.

 6.0  SUMMARY OF SITE RISKS

The assessment of risk posed by the Monsanto site was  evaluated in a
 site specific risk assessment dated September  1990.  This  assessment

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14
examined the amount, concentration, properties, environmental fate
and transport of the arsenic found at the site, and the populations
and environments potentially at risk. The risks associated with the
Monsanto site were calculated based on current and future exposure
scenarios. The numerical cancer.risk values are theoretical
quantifications of the excess lifetime cancer risk, that is, the
increased probability of contacting cancer as a result of exposure to
wastes, compargd to the probability if no exposure occurred. For
example, a 10- excess cancer risk represents an exposure that
could rgsult in one extra cancer case per million people exposed.
The 10- risk level is considered the goal for remediation at
Superfund sites [40 CFR 300.430 (e)(2)(i)(A)(2)].
6.1
IDENTIFICATION OF THE CONTAMINANT OF CONCERN
Based on the historical information relating to the site, sampling
results from the RI as well as supplemental sampling conducted in
June 1990, arsenic was selected to serve as the contaminant of
concern at this site. No other compounds, either organic or
inorganic, were detected with either sufficient frequency or
concentration during the sampling events.
6.2
EXPOSURE ASSESSMENT SUMMARY
Exposure assessment is the estimation of the magnitude, frequency,
duration, and routes of exposure to humans. Exposure to the arsenic
contaminated groundwater beneath the Monsanto Superfund site was
evaluated based on current and future use scenarios. Based on the RI
results, the only source of potential arsenic exposure at the
Monsanto site (including the adjacent landowners) is the surifical
aquifer beneath the site. Evaluation of all other media (soil,
surface water, air) on and near the site, indicated background or
non-detectable arsenic levels.
Under current land use conditions, no exposure to humans is occurring
due to incomplete exposure pathways. The closest residential area is
approximately one half mile northwest of the site and is
hydrogeologically upgradient. Downgradient from the site there are
no wells which7are used to obtain water from the surficial water
bearing zone. Water supply wells are completed in the underlying
Cretaceous aquifer; however, interconnection between the two water
bearing zones haa not been demonstrated during previous pumping
tests. The point of discharge for the upper zone is Phinizy Swamp.
Groundwater modeling projections indicate that the arsenic
concentration in the groundwater will be below the limit of detection
prior to reaching this discharge point. Groundwater sampling.
indicates the plume is currently limited to the Monsanto and adjacent
properties.
To address future use scenarios, conservative exposure assumptions
were developed by EPA. In conducting the exposure assessment, the

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                                   15

 focus was on  the health effects that could result from ingestion of
 arsenic  contaminated groundwater by adults working within the
 impacted area.  The assessment was limited to exposure via the
 workplace, rather than long term daily exposure, since the site is
 located  in an industrial setting.  Exposure was based upon a worker
 consuming one liter of water per day, 250 days per years from the
 well currently containing the maximum contaminant concentration
 (MW-35).  As  a result of contaminant dissipation, arsenic levels in
 MW-35 are expected to decline.  Projections of the maximum future
 exposure point concentrations can be found in Table 3.  Exposure
 duration was  developed based on the  full length of time arsenic
 concentrations in MW-35 remain above the MCL (0.05 mg/1) as well as
 above background concentrations (0.025 mg/1).

 6.3  TOXICITY ASSESSMENT SUMMARY

 Potential effects of chronic exposure to nonearcinogenic compounds
 are assessed  by comparing the exposure levels with Reference Dose
 (RFD) levels.  The RFD is an estimate of the average daily intake
 that will result in no adverse health effects.  Currently EPA's
 Integrated Risk Information System does not list any RFDs for
 arsenic.  The primary health effect  concern relating to exposure to
 arsenic  is cancer.

 Arsenic  is classified as a Group A human carcinogen.  This means that
 there is evidence that arsenic is carcinogenic in humans.  Ingestion
 of arsenic is associated with increased incidence of skin cancer.
 Unlike noncarcinogens, carcinogens do not have threshold exposure
 levels which  will result in no adverse health effects.  Rather,
 cancer potency factors (CPFs) are developed for estimating the excess
 lifetime cancer risks associated with exposure to carcinogens.  The
 excess cancer risk is a function of  the CPF and the exposure dose.
 The CPF proposed for arsenic is 1.75  (mg/kg/day)"1.

 6.4  RISK CHARACTERIZATION SUMMARY

 Risk characterization involves combining the results of the exposure
 and toxicity  assessments to develop  a numerical estimate of health
 risk.  Risk is"a probability that is generally expressed in
 scientific notation (i.e. 1 x 10"6).  An excess cancer risk of  1  x
 10~6 indicates that an individual has a one in one million chance
 of developing cancer as a result of  site related exposure to a
 carcinogen based on the specific exposure conditions at the site.
 EPA has established a range of 10    to 10"6 for individual cancer
 risk.

As stated in  the exposure assessment, there currently exists no
 exposure pathways to the contaminated groundwater.  However,
 projected future exposure through ingestion of the contaminated
 groundwater at the workplace was calculated.  Based on  intake  values
 prom exposure to levels in excess of the MCL, the cumulative risk was
 4.15 x 10" .  The risk associated with exposure to above background

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16
TABLE 3
PROJECTED ARSENIC CONCENTRATIONS MONITORING WELL 35
Year Concentrations Iccbl
1990 85.0t (71.61:
1991 53.0:
1992 32.0:
1993 25.0.
t Actual field data January, 1990
: Projected concentrations from PLUME model
. Background
- .

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                                   17

 concentrations was 4.76 x  10~  .  It  should be noted, risk
 assessments rely on toxicity extrapolation and modeled exposure
 estimates; therefore/ conservative assumptions are used to evalute
 the worst reasonable situation.  Although, based on the limited
 exposure scenario considered reasonable at the Monsanto site,
 consumption of the arsenic contaminated groundwater falls within the
 risk range; the levels exceed  the Federally regulated drinking water
 standard (i.e. MCL) for arsenic of 0.05 mg/1.

 6.5  ENVIRONMENTAL RISK SUMMARY

 Since the arsenic contamination is limited to the groundwater, direct
 contact by environmental receptors does not occur at the present
 time.  Modeling indicates  that at the point of discharge to the
 environment, Phinizy Swamp, arsenic  levels will be at background
 levels.

 Based on the industrial exposure scenario, the risk associated with
 human ingestion of the contaminated  groundwater at the workplace
 should fall within the established risk range.  A risk based
 remediation level was not  established for groundwater restoration
 since there currently exists an applicable or relevant and
 appropriate requirement for arsenic  (i.e. MCL).  The MCL, as
 established by the Safe Drinking Water Act, represents an enforceable
 Standard to regulate the maximum permissible level of a contaminant
 in public drinking water supplies.   Wells with values above drinking
 water standards are not suitable for use as a lifetime drinking water
 supply.  The MCL of 0.05 mg/1  is exceeded in two wells downgradient
 from Landfill #2 (MW-17 and MW-35).  Because these wells exceed the
 MCL, continued releases of hazardous substances from this 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.

 7.0  DESCRIPTION OF ALTERNATIVES

 Four alternatives were considered for remediation of the arsenic
 contaminated groundwater at the Monsanto Superfund site.  The
 alternatives are evaluated in  detail in the Feasibility Study
 Report.  All of the alternatives, except the "No Action" alternative
 require continued quarterly monitoring of the groundwater to
 reevaluate the plume boundary  and post remediation monitoring to
 verify the effectiveness of the remedial action.

 7.1  ALTERNATIVE  1 - NO ACTION

 The Superfund program requires the  "No Action" alternative be
considered at every site [Section 300.430  (e) of the National
Contingency Plan].  The no action alternative serves as a baseline
--'th which the other alternatives can be compared.  Under the no
  tion alternative, EPA would  take no further action at the  site  to
-ontrol or minimize the migration of the arsenic contaminated

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                                   18

 groundwater.   Since no  additional groundwater monitoring will be
 conducted, wells currently at the site would be decommissioned as
 part of  the no action alternative.  The present worth cost associated
 with this alternative is  approximately $71,000.

 7.2  ALTERNATIVE 2 - ESTABLISH AN INTERIM ALTERNATE CONCENTRATION
                      LIMIT

 Remedial action alternative 2 involves the establishment of an
 interim  level  of remediation, or alternate concentration limit (ACL),
 which  is protective of  human health and the environment. An ACL may
 be developed when there is a known point of entry of the groundwater
 into a surface water body, there is no increase of site related
 contaminants at the point of entry, and there are enforceable
 measures to preclude human exposure to the contaminated groundwater
 between  the site and the  point of entry [CERCLA 121 (d)(2)(B)(ii)].
 The ACL  criteria are met  at the Monsanto site.  The point of entry of
 the groundwater is Phinizy Swamp.  The RI Report predicts no increase
 in the level of arsenic in the swamp due to the discharge of the
 groundwater into the swamp.  Groundwater restrictions would be
 negotiated with downgradient landowners to preclude exposure to the
 contamination  in the surficial aquifer.

 The ACL  would  be an interim action level until the MCL is obtained
 through  natural dissipation.  Arsenic levels in MW-35 would be
 monitored on a quarterly  basis to ensure the ACL was not exceeded at
 any time during the attenuation period.  In addition, numerous wells
 in the area  of the current plume of contamination would be monitored
 for continued  compliance  with the MCL.  These wells would be
 designated during the design phase prior to site remediation.
 Exceedances of the MCL  in any of these wells for two consecutive
 quarters would require  a  re-evaluation of the remedy's
 protectiveness.  Groundwater use restrictions, to be obtained during
 the design phase, would be necessary for the duration of arsenic
 levels associated with  the Monsanto site that remain above the MCL.
 Following the  attainment  of the MCL at the site, monitoring would
 continue for 4. minimum  of two years to verify the effectiveness of
 the remedy.

 Based  on the modeling effort conducted during the RI, the remediation
 goal of  the MCL will be attained at the core of the plume within  5
 years  (1995).   The present worth cost of alternative 2  is
 approximately  $250,000.   This cost includes the two year post
 remediation monitoring  as well as post remediation well plugging.

 7.3  ALTERNATIVE 3 - PUMP AND DISCHARGE

Alternative 3  includes  the design of an extraction well system to
 remove the contaminated groundwater  from the surficial  aquifer.   The
 extracted groundwater would be discharged to the City of Augusta's

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19
POTW to reduce the arsenic concentrations to the MCL. If, during the
design of this alternative, a determination is made that the POTW
discharge is not feasible, an equivalent discharge method would be
developed. The extraction system would operate until the MCL is
obtained at the site for two consecutive quarterly sampling events.
Groundwater use restrictions on the surficial aquifer and site access
would be required during this period.

Following the attainment of the MCL for three consecutive quarters,
groundwater sampling would continue for two additional years to
monitor the success of the remedial action. Groundwater samples
would be collected from monitoring wells designated during the
remedial design.
During the design of the extraction well system, quarterly
groundwater monitoring would continue. The initiation of the
construction activities may be deferred based on the results of the
quarterly sampling effort conducted during the remedial design.
GPALs have been established by EPA based on the future contaminant
levels predicted by the modeling effort in the RI Report. Failure to
meet the annual GPAL specified on Table 4 for MW-35, as well as
MW-17 , would require the immediate initiation of the construction
phase for the remedial action. In addition, any verified exceedances
of the MCL in the monitoring wells other than MW-17 and MW-35 would
require the initiation of construction activities. Exceedances of
the MCL during a single quarterly sampling effort would be confirmed
by EPA during the subsequent quarter's sampling. However, as long as
the GPALs are achieved, the construction phase would be deferred.

The total present worth cost for this alternative is approximately
$600,000. This cost includes the design, construction and
implementation of the remedial action as well as decommissioning the
wells. Assuming construction is initiated immediately following the
remedial design, the duration for these activities is estimated to be
4 years. The cost also includes 2 additional years of post
remediation mo~itoring.
7.4
ALTERNATIVB 4 - PUMP AND TREAT ONSITE
This alternative is similar to Alternative 3 except the extracted
g~oundwater would be treated onsite rather than at the POTW.
Treatability studies would be required, as part of the design, to
evaluate the most effective technology to reduce the arsenic
concentration in the contaminated groundwater. Achievement of the
GPALs as specified on Table 4 would defer the initiation of the
construction phase of the remedial action. Non-compliance with the
GPALs may require the initiation of construction activities. Onsite

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20
TABLE 4
GROUNDWATER PROTECTION ACHIEVEMENT LEVELS
 Monitoring Wells (MW) 17 and 35 
Year  Concentration lua/l)
1991    71.6 
1992    53.0 
1993 and thereafter   50.0 
 Wells other than MW-17 and 35 
1991 and thereafter   50.0 
- .

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21
treatment may generate a hazardous treatment sludge. Tests would be
conducted to determine the nature of the sludge from a particular
treatment unit. Treatment sludge would be collected and stabilized,
if necessary. The sludge would then be transported to a permitted,
off-site, commercial facility for land disposal. The surficial
aquifer would be recharged by the treated groundwater from the
effluent from the treatment unit. .
Estimated present worth costs for the onsite treatment of the arsenic
contaminated groundwater is approximately $1,500,000. The timeframe
for site remediation is similar to Alternative 3.
8.0
SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
This section of the ROD provides the basis for determining which
alternative provides the best balance with respect to the statutory
balancing criteria in Section 121 of CERCLA and in Section 300.430 of
the NCP. The major objective of the FS was to develop, screen, and
evaluate alternatives for remediating the Monsanto Superfund site.
Several remedial technologies were identified for groundwater
restoration. These technologies were screened based on their
feasibility with respect to the contaminants present and the site
characteristics.
The technologies that remained after the initial screening were
evaluated in detail. EPA has established nine criteria for
evaluating potential remedial alternatives. A glossary of these
evaluation criteria is provided in Table 5. These evaluation
criteria have been divided into three groups based on the function of
the criteria in remedy selection. The first two criteria on Table 5
are threshold criteria. These two criteria relate to statutory
requirements that each alternative must satisfy in order to be
eligible for selection. The next five criteria are balancing
criteria. These are technical criteria upon which the detailed
analysis is primarily based. The final two criteria on Table 5,
known as modi~ing criteria, assess the public's and state agency's
acceptance of the alternative. Based on these final two criteria,
EPA may modify aspects of the specific alternative.

A sUDDDary of the relative performance of the alternatives with
respect to each of the nine criteria is provided in this section. A
comparison is made between each of the alternatives for achievement
of a specific criterion.
8.1
OVERALL PROTE.CTION OF HUMAN HEALTH AND THE ENVIRONMENT
All of the alternatives, with the exception of the "No Action"
alternative, would provide protection of human health and the
environment by eliminating or controlling exposure to contaminated

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                                   22
                                TABLE 5



                    GLOSSARY OF EVALUATION CRITERIA
Overall Protection of Human Health and the Environment - addresses
whether or not a remedy provides adequate protection and describes
how exposure to the contaminated groundwater would be eliminated or
controlled through treatment or institutional controls.

Compliance with ARARs - addresses whether or not a remedy will meet
all of the applicable or relevant and appropriate requirements of
other Federal and State environmental statutes and/or provides
grounds for invoking a waiver.

Short Term Effectiveness - refers to the level of protection the
remedy would achieve during the construction and implementation
period as well as the remedy's potential to create adverse impacts on
human health and the environment during this same period.

Long Term Effectiveness - refers to the ability of a remedy to
maintain reliable protection of human health and the environment over
time once the drinking water standard has been met.

Reduction of Toxicity» Mobility, or Volume Through Treatment - is the
anticipated performance of the treatment technologies that may be
employed in a remedy.

Implementability - is the technical and administrative  feasibility of
a remedy.

Cost - includes capital and operation and maintenance costs.  The
costs are reported as present worth cost.

Community Acceptance - is assessed in the Responsiveness Summary  in
Appendix C of-this Record of Decision.  The Responsiveness Summary
was developed based on comments received during the comment period
for this remedial action.

State Acceptance - indicates whether the State of Georgia concurs
with, opposes, or has no comment on the preferred alternative.

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23
groundwater through treatment or institutional controls. The No
Action alternative fails to provide any controls to restrict exposure
to the contaminated groundwater. Alternative 2 relies on
institutional controls for protection until contaminant levels
naturally dissipate to levels below the MCL. Alternatives 3 and 4
rely on treatment to eliminate exposure by actively remediating the
groundwater if deemed necessary based on non-compliance with GPALs.
8.2
COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE
REQUIREMENTS (ARARs)
Although based on modeling conducted during the RI arsenic levels are
projected to naturally attenuate to below the ARAR for potential
drinking water sources (i.e. MCL), alternative 1 provides no measures
to verify the potential reduction nor would there be any contingency
plans. Alternatives 2, 3, and 4 would all comply with potential
Federal and State ARARs.
8.3
SHORT TERM EFFECTIVENESS
The No Action alternative would not be effective as unrestricted
usage of impacted surficial aquifer could occur since no groundwater
controls would be implemented. The interim ACL alternative (t2)
would provide short term effectiveness to human health through
restricting usage of the contaminated groundwater. As with the
interim ACL alternative, the active restoration alternatives (t3 and
4) would require controls be placed on groundwater usage during site
remediation. Should the GPALs not be complied with during the design
period, Alternatives 3 and 4 would rely on an extraction well system
to intercept the arsenic plume; thus minimizing the migration of the
plume.
8.4
LONG TERM EFFECTIVENESS AND PERMANCE
The long term objective for remediating the arsenic contaminated
groundwater is the attainment of the MCL. All of the alternatives
are projected~to achieve the MCL through either treatment or natural
dissipation. Bowever, since monitoring would not be conducted as
part of the No Action alternative, verification of the potential
attainment of the MCL would not be possible.
8,.5
REDUCTION 0' MOBILITY, TOXICITY OR VOLUME THROUGH TREATMENT
Although contaminant levels at the core of the plume are projected to
dissipate over a 5 year period, the No Action alternative would not
provide any verification of this reduction. Alternative 2 also
relies on natural dissipation to reduce mobility, toxicity or volume;
however, reductions would be monitored. While treatment is not
tncorporated into Alternative 2, a reduction of arsenic, through
~atural dissipation, is expected to occur with this alternative.

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24
Although the reduction would be verified, this alternative does not
provide for the immediate active restoration should natural
dissipation not occur. The extraction well system required with
Alternatives 3 and 4, should attainment of the GPALs not be achieved
during the design phase of the project, would minimize the migration
of the plume. The treatment process would remove the arsenic
contamination from the surficial aquifer.
8.6
IMPLEMENTABILITY
The No Action alternative is relatively easy to implement since it
simply involves plugging the existing wells. The interim ACL remedy
requires continued quarterly monitoring during the estimated duration
of the project. ~though Alternative 3 (groundwater extraction and
PQTW discharge) requires the design of the extraction well system,
the extraction well system would not be innovative and construction
activities would not be difficult. Onsite treatment of the arsenic
contaminated groundwater would be more difficult to implement in
comparison with the other alternatives. ~though the extraction well
system would not be innovative, the construction and operation of an
onsite treatment unit would be more difficult than ~ternative 3.
8.7
COST
The present worth cost of each alternative includes the capital cost,
annual remediation operation and maintenance, and annual post
remediation operation and maintenance. All estimated costs assume
10' interest per year for the entire duration of the project. The
cost associated with the No Action alternative ($71,000) is for the
decommissioning of the existing monitoring wells. ~ternative 2 has
a higher cost compared to alternative 1 since quarterly monitoring
will continue for an extended period of time. The total present
worth cost for the interim ACL action is $250,000. The present worth
cost of alternative 3 (POTW discharge) is $600,000. ~ternative 4
(onsite treatment) has a present worth cost of $1,500,000.
Alternatives 3 and 4 both require the design and construction of the
extraction weU systemJ however, Alternative 4 also includes costs
associated with' the construction and operation of the treatment unit.
8.8
COMMUNITY ACCEPTANCE
Based on comments received during the public comment period, the
community was opposed to the No Action alternative and the
establishment of an ACL (Alternative 2). The community favors active
restoration to reduce the arsenic levels in the groundwater to the
drinking water standard and supports the selection of Alternative 3.

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                                   25

 8.9   STATE ACCEPTANCE

 The  State of Georgia  (Environmental Protection Division) has also
 stated a preference for active restoration at the Monsanto site.  The
 State has concurred with the selection of alternative 3 as the
 preferred alternative for the remediation of the arsenic contaminated
 groundwater associated with the Monsanto site (Appendix C).


 9.0   SELECTED REMEDY

 EPA's preferred alternative for the protection of human health and
 the  environment at the Monsanto site is alternative 3, which consists
 of the continued monitoring of arsenic levels in the surficial
 aquifer to evaluate compliance with GPALs, extraction of contaminated
 groundwater and discharge the groundwater to the POTW should
 non-compliance with GPALs occur.  The remediation level will be the
 MCL  enforced by EPA prior to the completion of the remedial design
 (MCL is currently 0.05 mg/1).  In addition, the alternative involves
 post remediation monitoring for a minimum of two years following
 EPA's acceptance the MCL has been attained.

 Arsenic contamination of the surficial aquifer is currently limited
 to two monitoring wells directly downgradient of Landfill #2.  During
 the  design phase of the project, monitoring on a quarterly basis
 (January, April, July and October) will continue such that EPA will
 continue to re-evaluate the boundary of the plume.  The data obtained
 from MW-35 and MW-17 during each monitoring event will be averaged
 annually and compared with the annual GPAL on Table 4.  Should the
 arithmetic annual average arsenic level in either MW-35 or MW-17
 exceed the GPAL for that year, the initiation of construction
 activities will be required following the completion of the remedial
 design.  In addition, should EPA verify the detection of arsenic
 concentrations in excess of the MCL in any of the remaining wells,
 construction of the remedy will be required.  Compliance with the
 GPALs may defer or eliminate the need for the initiation of
 construction activities.

 During the remedial design, access will be obtained from downgradient
 landowners impacted by the expanding plume.  Access will be necessary
 to install extraction wells and distribution lines, to conduct
quarterly groundwater monitoring and to service the extraction well
 system during site remediation.  Design activities will also include
obtaining permission to discharge the wastewater to the POTW.   Since
the maximum arsenic levels are over ten times less than the level
currently accepted by the POTW, this discharge method is preferred.
However, should difficulties arise during the design in obtaining
POTW acceptance, an equivalent discharge method will be incorporated
 into the remedial design.

 >ased on current information, the selected remedy provides  the  best

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                                   26

 balance  of  the nine criteria that EPA uses to evaluate each remedial
 alternative for this site.  The rationale for selecting Alternative 3
 includes:

     *  Alternative 3 provides short and long term protection of human
       health and the environment from potential threats associated
       with direct contact  (ingestion) of the contaminated
       groundwater, and

     *  Alternative 3 provides for immediate initiation of active
       restoration should the GPALs not be achieved at the site.


 10.0  STATUTORY DETERMINATIONS

 The USEPA has determined that this remedy will satisfy the statutory
 requirements of Section 121 of CERCLA by providing protection of
 human health and the environment, attaining ARARs, providing cost
 effectiveness/ and utilizing permanent solutions and alternative
 treatment technologies or resource recovery technologies to the
 maximum  extent practicable.

 10.1  PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT

 The selected remedy adequately protects human health by reducing the
 arsenic  levels in the surficial aquifer currently in excess of the
 drinking water standard (MCL) of 0.05 mg/1.  The remedy also relys on
 groundwater use restrictions to prohibit the usage of the
 contaminated groundwater until the MCL is attained.  Should
 construction activities be  required, protection of human health and
 the environment will be accomplished through the minimization of the
 migration of the plume via  the extraction well system and arsenic
 reduction.

 10.2  ATTAINMENT OF APPLICABLE OR RELEVANT AND APPROPRIATE
      REQUIREMENTS

 Remedial actions performed  under CERCLA, as amended by SARA, must
 comply with all ARARs or provide a justifiable waiver.  The selected
 remedy for  the Monsanto site was found to attain the ARARs.

 This remedy assures that, following site remediation, the surficial
 aquifer beneath the Monsanto site boundary  (which includes adjacent
 property impacted by the groundwater contamination) will meet  the  MCL
 which is being enforced by  EPA at the completion of the remedial
 design.  The MCL is an ARAR under the Federal Safe Drinking Water  Act
 as well as  the Georgia Safe Drinking Water Act.  In addition to the
MCL, the remedial action will be designed consistent with the
 requirements of an existing permit [HW-074(S)] issued by the State of
 Georgia under the Resource  Conservation and Recovery Act  (RCRA) as
well as the City of Augusta's pretreatment  standards for wastewater
 discharges  to the POTW (Ordinance 5148).  The intent of the State  of

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                                   27

 Georgia's Groundwater Use Rules will be complied with under this
 action  since groundwater extraction is anticipated; however, permits
 are not required for onsite Superfund actions [40 CFR 300.400(e)].
 All activities conducted under this remedial action will be performed
 in accordance with the Federal Occupational Safety and Health
 Administration Act (OSHA).

 10.3  COST EFFECTIVENESS

 The present estimated cost of EPA's selected remedy is $600,000.
 Cost effectiveness is determined by comparing the costs of all
 alternatives being considered with their overall effectiveness to
 determine whether the costs are proportional to the effectiveness
 achieved.  The selected remedy, Alternative 3, although more costly
 than Alternatives 1 and 2, provides a higher degree of
 protectiveness.  EPA has determined that the costs of the selected
 remedy  are proportionate to the overall effectiveness; therefore, the
 remedy  is considered cost effective.

 10.4  UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT
        TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE

 EPA has determined that the selected remedy provides the best balance
 among the nine evaluation criteria for the four alternatives
 evaluated.  The selected remedy provides protection of human health
 and the environment, reduces the mobility of the plume, and is cost
 effective.  The remedy, when complete, will be permanent.  The remedy
 represents the maximum extent to which permanent solutions and
 treatment can be practicably utilized to remediate the Monsanto site.

 10.5  PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT

The statutory preference for treatment will be met by the selected
remedy.  The remedy relies on active groundwater restoration rather
than natural attenuation.  The surficial aquifer contaminated with
arsenic will be treated, as required by pretreatment standards, or
treated at the. POTW.

 11.0  DQCUMEMTATION OF SIGNIFICANT CHANGES

EPA issued a Proposed Plan (preferred alternative) for remediation of
the site on October 30, 1990.  The selected remedy does not differ
from the Proposed Plan.

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- ""
. - .
APPENDIX A
ADMINISTRATIVE RECORD INDEX
Monsanto Superfund Site
Augusta, Georgia

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DRAFT, 09/18/90, 16:14
Page 1
ADMINISTRATIVE RECORD INDEX
for the
MONSANTO CO NPL Site
1.0
PRE-REMEDIAL
1.8
PrelLminary Assessment Documents

1. "Potential Hazardous Waste Site - Identification and
PrelLminary Assessment" Form, EPA Region IV (December
6, 1979).
1.9
Site Inspection Documents

1. "Inventory and Evaluation - Tract Located Between
Georgia Highway 56 and Central Georgia Railroad,"
Philip S. Hadarits, USDA-Soil Conservation Service
(March 25, 1980).
2. "Potential Hazardous Waste Site - Site Inspection
Report" Form, EPA Region IV (June 20, 1980).
3. "Potential Hazardous Waste - Tentative Disposition"
Form, EPA Region IV (October 1, 1980).

4. "Potential Hazardous Waste Site - Final Strategy
Determination- Form, EPA Region IV (November 2, 1980).
1.10
Expanded Site Inspection Documents
1. Memorandum from Dam Thoman, EPA Region IV to David
Melgaard, EPA Region IV (April 26, 1988). Concerning
QA/QC overview of Dames and Moore personnel at the
Monsanto Company Site in Augusta, Georgia.

2.7.X8IIIOrandua from Roqer E. Carlton, EPA Reqion IV
-Bnvironmental Services Division, Athens, Georqia to
David Melqaard, EPA Reqion IV (August 31, 1988).
Concerninq attached Monsanto Company Field
Inv..tiqation Report.
3. "Field Investiqation Report - Monsanto NPL Site -
Augusta, Richmond County, Georqia,. EPA Reqion IV
(August 7, 1990).

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,
DRAFT, 09/18/90, 16:14
Page 2
2.0
REMOVAL RESPONSE
2.2
Sampling and Analysis Data
~e Sampling and Analysis Data for the Removal Response
may be reviewed, by appointment only, at EPA Region IV,
Atlanta Georgia, and at EPA Region IV Environmental
Services Division, Athens Georgia.
1. Letter from George D. Rozelle, Monsanto Company to
Jennifer Kaduck, Georgia Environmental Protection
Division (December 27, 1979). Concerning attached
interim geological/hydrological report on the two on-
site landfills at Monsanto's Augusta Plant.
2.8
Removal Response Reports
1. "Report - Soil Sampling and Testing of Existing
Landfills - Augusta, Georgia Facility for Monsanto
Chemical Company," Dames, Moore (December 22, 1983).

2. Letter from George D. Rozelle, Monsanto Company to J.
Leonard Ledbetter, Georgia Environmental Protection
Division (December 28, 1983). Concerning completion
of the excavation, transportation and disposal at the
Monsanto Company Site in Augusta, Georgia.
3. "Draft - Monsanto Chemical Company - August, Georgia -
Landfill Removal Project," Monsanto Chemical Company
(October 1986).

4. "Report - Hydrologic Slug - Testing of Monitoring
Wells Two Po~er Landfill Areas, Augusta, Georgia for
Monsanto Chemical Company," Dames' Moore (March 5,
1987).
s. Letter from George D. Rozelle, Monsanto Chemical
Company to Brian A. Donaldson, EPA Region IV (December
.7-14, 1987). Concerning meeting to discuss status of
the fat. and transport modeling work and progress on
the landfill cleanup evaluation project.

6. -MOnsanto - Augusta, GA - Landfill Cleanup Project
Conclusions," Georgia Department of Natural Resources
(February 22, 1988).
7. "Augusta Arsenic Pate and Transport Study," Monsanto
Company (August 1, 1988).

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DRAFT, 09/18/90, 16:14                                   Page 3


   2.8   Removal Response Reports  (cont'd.)

       8. Memorandum from David Melgaard, EPA Region  IV to File,
          EPA Region IV (August 27,  1988).  Concerning attached
          memo from Camp, Dresser  and McKee, Inc.

3.0   REMEDIAL INVESTIGATION (RI)

   3.1   Correspondence

       1. Letter from Meredith Clarke Anderson,  EPA Region IV to
          G.F. Benjamin,  Monsanto  Chemical Company (August 8,
          1986).  Concerning the listing of the  Monsanto Company
          Site on the Environmental  Protection Agency's  (EPA)
          National Priorities List (NPL).

       2. Letter from Meredith Clarke Anderson,  EPA Region IV to
          George D. Rozelle, Monsanto Chemical Company  (October
          20, 1986).  Concerning results of the  initial  review
          of background information  and data on  the Monsanto
          Company Site.

       3. Letter from Meredith Clarke Anderson,  EPA Region IV to
          George O. Rozelle, Monsanto Chemical Company  (November
          28, 1986).  Concerning results of the  November 12,
          1986 meeting between EPA Region IV and Monsanto
          Chemical Company.

       4. Letter from George D. Rozelle, Monsanto Chemical
          Company to Meredith Clarke Anderson, EPA Region  IV
          (December 8, 1986).  Concerning the delisting of
          Monsanto Company Site in Augusta, Georgia.

       5. Memorandum from G. Behrens, Camp, Dresser and McKee,
          Inc. to D. Lawton, Camp, Dresser and McKee, Inc.
          (March 25, 1987).   Concerning Monsanto Sampling Trip
          Report.

       6. Latter from Janes B. McGuire, EPA Region IV to
         ..Addressees, EPA Region IV (May 29,  1990).  Concerning
          request for peer review of the Monsanto Company Site
          draft Remedial Investigation Report.

       7. Letter from James E. McGuire, EPA Region IV to James
          Lee, United States Department of the  Interior (May 29,
          1990).  Concerning request for review of the Monsanto
          Company Site draft Remedial Investigation Report.

       8. Letter from James E. McGuire, EPA Region IV to
          Jennifer Kaduck, Georgia Environmental Protection
          Division (July 26, 1990).   Concerning transmittal of
          the draft Remedial Investigation Report for the
          Monsanto Company Site.

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DRAFT/ 09/18/90, 16:14                                   Page 4


   3.2   Sampling and Analysis Data

      The Sampling and Analysis Data for the  Remedial
      Investigation may be reviewed, by appointment  only, at
      EPA Region IV, Atlanta Georgia,  and at  the  EPA Region IV
      Environmental Services Division,  Athens,  Georgia.


       1. Letter from David Melgaard,  EPA Region  IV  to George D.
          Rozelle, Monsanto Chemical Company  (April  26,  1988).
          Concerning verification of the sampling and analytical
          methods used at the Monsanto Company Site  in Augusta,
          Georgia.

       2. Memorandum from David Melgaard, EPA Region IV  to  Doug
          Lair, EPA Region IV (June 23, 1988).  Concerning
          probable cross contamination of samples from the
          Monsanto Company Site in Augusta, Georgia.

       3. Letter from David Melgaard,  EPA Region  IV  to George  D.
          Rozelle, Monsanto Chemical Company  (June 23,  1988).
          Concerning EPA's comments on sampling collection
          procedures at the Monsanto Company  Site in Augusta,
          Georgia.

       4. Cross-Reference:  "Monsanto - Augusta Plant Site  -  RI/
          FS Final Work Plan," Dames & Moore  (July 26,  1989).
          [Filed and cited as entry number 10 in  3.4 REMEDIAL
          INVESTIGATION (RI) - Work Plans and Progress  Reports]

       5. "Arsenic, Sodium, Total Phosphorus  CLP  Protocol,"
          Savannah Laboratories and Environmental Services, Inc.
          for Dames & Moore (January 1990).

       6. Analytical Report from Savannah Laboratories and
          Environmental Services, Inc. to Dale P. Voykin, Dames
          & Moore (January 9, 1990).  Concerning analytical
          results of liquid samples from the Monsanto Company
          Site in Augusta, Georgia.
         . 9-
       7. Memorandum from Wade Knight, EPA Region IV to David B.
          Abbott, EPA Region IV (March 12, 1990).  Concerning
          data package from the Potentially Responsible Parties'
          (PRP) laboratory, Savannah Laboratories and
          Environmental Services, Inc.

       8. Memorandum from David W. Hill, EPA Region IV to David
          B. Abbott, EPA Region IV  (March 14,  1990).  Concerning
          Arsenic Equilibrium Modeling for Well MW-35 at the
          Monsanto Company Site in Augusta, Georgia.

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DRAFT, 09/18/90, 16:14                                   Page 5


   3.4   Work Plans and Progress  Reports

       1. Memorandum from David W.  Hill,  EPA  Region  IV to David
          B.  Abbott, EPA Region IV (June  14,  1989).  Concerning
          review of the RI/FS Work Plan for the  Monsanto Company
          Site in Augusta, Georgia.

       2. Letter from David B. Abbott,  EPA Region IV to Betsy A.
          Briggs, Dynamac Corporation (June 14,  1989).
          Concerning review of the RI/FS  Work Plan for the
          Monsanto Company Site in Augusta, Georgia.

       3. Memorandum from Rebecca Fox,  EPA Region IV to David B.
          Abbott, EPA Region IV (June 16, 1989).  Concerning
          review of the RI/FS Work Plan for the  Monsanto Company
          Site in Augusta, Georgia.

       4. Letter from David B. Abbott,  EPA Region IV to George
          D.  Rozelle, Monsanto Company (June  23, 1989).
          Concerning review of the RI/FS  Work Plan for the
          Monsanto Company Site in Augusta, Georgia.

       5. Letter from Roger E. Carlton, EPA Region IV
          Environmental Services  Division, Athens, Georgia  to
          Douglas Mundrick, EPA Region IV (June  26,  1989).
          Concerning review of the RI/FS  Work Plan for  the
          Monsanto Company Site in Augusta, Georgia.

       6. Memorandum from Lee Page, EPA Region IV to Douglas
          Mundrick, EPA Region IV (July 5, 1989).  Concerning
          review of the RI/FS Work Plan for the  Monsanto  Company
          Site in Augusta, Georgia.

       7. Letter from Joe Hughart, Agency for Toxic Substances
          and Disease Registry (ATSDR) to David  B. Abbott,  EPA
          Region IV (July 6, 1989).  Concerning  review of the RI/
          FS  Work Plan for the Monsanto Company Site in Augusta,
          Georgia.

      ' 8~ Memorandum from Winston A. Smith,  EPA Region IV to
          Patrick M. Tobin, EPA Region IV (July 10, 1989).
          Concerning review of the RI/FS Work Plan for the
          Monsanto Company Site in Augusta,  Georgia.

       9. Letter from Charles T.  Allen, Dames &  Moore to David
          B.  Abbott, EPA Region IV (July 21,  1989).  Concerning
          response to comments on the RI/FS Work Plan for the
          Monsanto Company Site in Augusta,  Georgia.

      10. "Monsanto - Augusta Plant Site - RI/FS Final Work
          Plan," Dames & Moore (July 26,  1989).

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DRAFT, 09/18/90, 16:14                                   Page 6


   3.4   Work Plans and Progress Reports  (cont'd.)

      11. Letter from David B.  Abbott,  EPA Region  IV to George
          D. Rozelle, Monsanto  Company (August  29,  1989).
          Concerning review of  the Final  RI/FS  Work Plan  for  the
          Monsanto Company Site in Augusta, Georgia.

      12. Letter from George D. Rozelle,  Monsanto  Company to
          David B. Abbott, EPA  Region IV  (September 6, 1989).
          Concerning monthly progress report for August 1989.

      13. Letter from George D. Rozelle,  Monsanto  Company to
          David B. Abbott, EPA  Region IV  (October  5,  1989).
          Concerning monthly progress report for September  1989.

      14. Letter from George D. Rozelle,  Monsanto  Company to
          David B. Abbott, EPA  Region IV  (November 9,  1989).
          Concerning monthly progress report for October  1989.

      15. Letter from George D. Rozelle,  Monsanto  Company to
          David B. Abbott, EPA  Region IV  (December 7,  1989).
          Concerning monthly progress report for November 1989.

      16. Letter from George D. Rozelle,  Monsanto  Chemical
          Company to David B. Abbott, EPA Region IV (December
          18, 1S89).  Concerning Landfill Delisting Project and
          Work Plan Interpretation.

      17. Letter from George D. Rozelle,  Monsanto  Company to
          David B. Abbott, EPA Region IV (January 8, 1990).
          Concerning monthly progress report for December 1989.

      18. Letter from George D. Rozelle,  Monsanto Company to
          David B. Abbott, EPA Region IV (February 5, 1990).
          Concerning monthly progress report for January 1990.

      19. Letter from George D. Rozelle,  Monsanto Company to
          David B. Abbott, EPA Region IV (March 9, 1990).
          Concerning monthly progress report for February 1990.
         . »
      20. Letter from George D. Rozelle,  Monsanto Company to
          David B. Abbott, EPA Region IV (April 5, 1990).
          Concerning monthly progress report for March 1990.

      21. Letter from George D. Rozelle,  Monsanto Company to
          James B. McGuire, EPA Region IV  (May 7,  1990).
          Concerning monthly progress report for April 1990.

      22. Letter from George D. Rozelle,  Monsanto Company to
          James B. McGuire, EPA Region IV  (June 7,  1990).
          Concerning monthly progress report for May 1990.

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DRAFT, 09/18/90, 16:14
Page 7
3.4
Work Plans and Progress Reports (cont'd.)
23. Letter from George D. Rozelle, Monsanto Company to
James E. McGuire, EPA Region IV (July 2, 1990).
Concerning monthly progress report for June 1990.

24. Letter from George D. Rozelle, Monsanto Company to
James E. McGuire, EPA Region IV (August 8, 1990).
Concerning monthly progress report for July 1990.
3.7
Applicable or Relevant and Appropriate Requirements
(ARARs)
1. Letter from James E. McGuire, EPA Region IV to George
D. Rozelle, Monsanto Company (June 26, 1990).
Concerning summary of June 22, 1990 meeting.

Interim Deliverables
3.8
1. Letter Report from Jack T. Camp, Camp, Dresser and
McKee, Inc. to Meredith Clarke Anderson (June 17,
1986). Concerning Monsanto Interim Letter Report.

2. Letter from Meredith Clarke Anderson, EPA Region IV to
Jack T. Camp, Camp Dresser' McKee, Inc. (July 14,
1986). Concerning review of the Interim Letter Report
prepared as part of the Forward Planning Study for the
Monsanto Company Site in Auqusta, Georgia.
3. Letter from Meredith Clarke Anderson, EPA Region IV to
George D. Rozelle, Monsanto Company (November 25,
1986). Concerning results of the November 12, 1986
meeting between EPA and Monsanto Company.

4. Letter from Meredith Clarke Anderson, EPA Region IV to
George D. Rozelle, Monsanto Company (February 9,
1987). Concerning request to review the draft Forward
Planning Study (FPS) for the Honsanto Company Site.
5.7~~randU8 from Cody Jackson, Agency for Toxic
Sub8tance8 and Disease Registry (ATSDR) to Meredith
Clarke Anderson, EPA Region IV (February 23, 1987).
Concerning review of the draft Forward Planning Study
(FPS) for the Honsanto Company Site.

6. Memorandum from Nick Ceto, EPA Region IV to Leonard
Nowak, EPA Region IV (February 24, 1987). Concerning
review of the draft Forward Planning Study (FPS) for
the Honsanto Company Site.

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DRAFT, 09/18/90, 16:14
Page 8
3.8
.'
Interim Deliverables (cont'd.)

7. Letter from George D. Rozelle, Monsanto Company to
Meredith Clarke Anderson, EPA Region IV (February 25,
1987). Concerning review of the draft Forward
Planning Study (FPS) for the Monsanto Company Site.
8. Memorandum from Tex Ann Reid, EPA Region IV to
Meredith Clarke Anderson, EPA Region IV (February 27,
1987). Concerning review of the draft Forward
Planning Study (FPS) for the Monsanto Company Site.

9. Letter from George D. Rozelle, Monsanto Company to
Meredith Clarke Anderson, EPA Region IV (March 10,
1987). Concerning review of the draft Forward
Planning Study (FPS) for the Monsanto Company Site.
10. Memorandum from John H. Mann, EPA Region IV to
Meredith Clarke Anderson, EPA Region IV (April 7,
1987). Concerning review of the draft Forward
Planning Study (FPS) for the Monsanto Company Site.

11. Letter from Meredith Clarke Anderson, EPA Region IV to
Jack T. Camp, Camp, Dresser and McKee, Inc. (May 15,
1987). Concerning completed peer review and revision
of the draft Forward Planning Study (FPS).
12. Memorandum from Fred Sloan, EPA Region IV
Environmental Services Division, Athens, Georgia to
Meredith Clarke Anderson, EPA Region IV (June 1,
1987). Concerning review of the draft Forward
Planning Study (FPS) for the Monsanto Company Site.

13. Letter from David Melgaard, EPA Region IV to George D.
Rozelle, Monsanto Company (October 12, 1988).
Concerning request for review of the draft Forward
Planning Study (FPS) for the Monsanto Company.
14. Memorandum from Joe Hughart, EPA Region IV to David
7.~lgaard, BPA Region IV (October 21, 1988).
Concerning review of the draft Forward Planning Study
(FPS) for the Monsanto Company Site.

15. Letter from George D. Rozelle, Monsanto Company to
David Melgaard, EPA Region IV (October 27, 1988).
Concerning Monsanto's comments on the draft Forward
Planning Study (FPS) for the Monsanto Company Site.
16. Memorandum from Roger E. Carlton, EPA Region IV
Environmental Services Division, Athens, Georgia to
David Melgaard, EPA Region IV (October 27, 1988).
Concerning review of the draft Forward Planning Study
(FPS) for the Monsanto Company Site.
~

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DRAFT, 09/18/90, 16:14
Page 9
3.8
Interim Deliverables (cont'd.)
17. "Final Forward Planning Study Report - Revision I -
Monsanto Site - Augusta, Georgia," EPA Region IV
(December 13, 1988).
0-
18. Letter from David B. Abbott, EPA Region IV to Jan
Simmons, Georgia Environmental Protection Division
(January 20, 1989). Concerning agreement of EPA to
assume lead for the Monsanto Company Site in Augusta,
Georgia.

19. Cross-Reference: "Monsanto - Augusta Plant Site - RIf
FS Final Work Plan," Dames & Moore (July 26, 1989).
[Filed and cited as entry number 10 in 3.4 REMEDIAL
INVESTIGATION (RI) - Work Plans and Progress Reports]
3.10
Remedial Investigation (RI) Reports
1. Memorandum from Roger E. Carlton, EPA Region IV
Environmental Services Division, Athens, Georgia to
Dick Dubose, EPA Region IV (October 27, 1989).
Concerning overview of the Remedial Investigation of
the Monsanto Company Site.
2. Memorandum from
E. McGuire, EPA
comments on the
Report for the
Kevin Koporec, EPA Region IV to James
Region IV (June 13, 1990). Concerning
draft Remedial Investigation (RI)
Monsanto Company Site.
3. Memorandum from Robert E. Safay, Agency for Toxic
Substances and Disease Registry (ATSDR) to James E.
McGuire, EPA Region IV (June 15, 1990). Concerning
review of the draft Remedial Investigation (RI) Report
for the Monsanto Company Site.

4. Memorandum from Roger E. Carlton, EPA Region IV
Environmental Services Division, Athens, Georgia to
Jame8 E. MCGuire, EPA Region IV (June 18, 1990).
.~Concerning comments on the draft Remedial
-"Inve8tigation (RI) Report for the Monsanto Company
Site.
5. Letter from James E. McGuire, EPA Region IV to George
D. Rozelle, Monsanto Company (June 20, 1990).
Concerning transmittal of EPA's comments on the draft
Remedial Investigation (RI) Report for the Monsanto
Company Site. .

6. Memorandum from David W. Hill, EPA Region IV to James
E. McGuire, EPA Region IV (June 26, 1990). Concerning
review of the draft Remedial Investigation (RI) Report
for the Monsanto Company Site.

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DRAFT, 09/18/90, 16:14                                  Page 10


   3.10  Remedial Investigation (RI)  Reports  (cont'd.)

       7. Letter from George 0.  Rozelle,  Monsanto Company to
          James E. McGuire,  EPA Region IV (July 23,  1990).
          Concerning transmittal of  the Final Remedial
          Investigation (RI) Report  for the Monsanto Company
          Site.

       8. "Monsanto - Augusta Plant  Site - Remedial
          Investigation - Final Report -• Volume I,"  Dames &
          Moore (July 23, 1990).

       9. "Monsanto - Augusta Plant  Site - Remedial
          Investigation - Final Report - Volume II," Dames  &
          Moore (July 23, 1990).

      10. Letter from Cynthia F. Zauner, Dames & Moore  to James
          E.  McGuire, EPA Region IV  (August 1, 1990).
          Concerning transmittal of  the tabulation  report,
          "Response to EPA Remedial  Investigation Report
          Comments, dated June 20,  1990.".

      11. Letter from James E. McGuire, EPA Region  IV to George
          D.  Rozelle, Monsanto Company (August 20,  1990).
          Concerning EPA's acceptance of the Final  Remedial
          Investigation (RI) Report  for the Monsanto Company
          Site in Augusta, Georgia.

      12. Letter from James E. McGuire, EPA Region  IV to Lael
          Butler, Georgia Environmental Protection  Division
          (September 5, 1990).  Concerning request  for  comments
          on the Final Remedial Investigation (RI)  Report  for
          the Monsanto Company Site  in Augusta, Georgia.

   3.11  Health Assessments

       1. Letter from David B. Abbott, EPA Region IV to Chuck
          Pietrosewicz, Agency for Toxic Substances and Disease
          Registry (ATSDR) (December 12, 1988).  Concerning
          review of the draft Preliminary Health Assessment for
         ^the Monsanto Company Site.

       2. "Preliminary Health Assessment for Monsanto
          Corporation," Agency for Toxic Substances and Disease
          Registry (ATSDR) (January 19, 1989).

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DRAFT, 09/18/90, 16:14                                   Page 11


   3.12  Endangennent Assessments

       1. Memorandum from Kevin Koporec, EPA Region IV to James
          E. McGuire, EPA Region IV (August 27, 1990).
          Concerning comments regarding the draft Risk
          Assessment Report (RA) for the Monsanto Company Site.

       2. Cross-Reference:  Memorandum from Robert E. Safay,
          Agency for Toxic Substances and Disease Registry
          (ATSDR) to James E. McGuire, EPA Region IV (August 28,
          1990).  Concerning review of the draft Feasibility
          Study Report and the draft Risk Assessment.  [Filed
          and cited as entry number 3 in 4.9 FEASIBILITY STUDY
          (FS) - Feasibility Study (FS) Reports]

       3. Letter from James E. McGuire, EPA Region IV to George
          D. Rozelle, Monsanto Company  (September 7, 1990).
          Concerning peer review comments on the Risk Assessment
          and Feasibility Study for the Monsanto Company Site  in
          Augusta, Georgia.

       4. "Monsanto - Augusta Plant Site - Risk Assessment  -
          Final Report," Dames & Moore  (September 14, 1990).

       5. Cross-Reference:  Letter from George D. Rozelle,
          Monsanto Chemical Company to James E. McGuire, EPA
          Region IV (September 14, 1990).  Concerning
          transmittal of the Final Feasibility Study Report (FS)
          and the Final Risk Assessment (RA) for the Monsanto
          Company Site in Augusta, Georgia.  [Filed and cited  as
          entry number 7 in 4.9 FEASIBILITY STUDY (FS) -
          Feasibility Study (FS) Reports]

4.0   FEASIBILITY STUDY (FS)

   4.1   Correspondence

       1. Memorandum from James E. McGuire, EPA Region IV  to
          Addressee*, EPA Region IV (August 16, 1990).
         ._Concerning request for peer review of draft
          Feasibility Study Report for  the Monsanto  Company Site,

       2. Letter from James E. McGuire, EPA Region IV to
          Jennifer Kaduck, Georgia Environmental Protection
          Division (August 16, 1990).   Concerning transmittal  of
          the draft Feasibility Study Report and draft Risk
          Assessment for the Monsanto Company  Site.

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   4.1   Correspondence (cont'd.)

       3. Letter from James E.  McGuire,  EPA Region  IV to James
          Lee, Department of the Interior (August 16, 1990).
          Concerning transmittal of the  draft  Feasibility Study
          Report and draft Risk Assessment for the  Monsanto
          Company Site.

   4.9   Feasibility Study (FS) Reports

       1. Memorandum from James E.  McGuire, EPA Region  IV to
          File, EPA Region IV (June 7,  1990).   A summary of the
          June 6, 1990 meeting with Monsanto Corporation
          concerning the Monsanto Company Site.

       2. Letter from Charles T. Allen,  Dames  & Moore to William
          H. McLemore, Georgia State Geologist (June 29, 1990).
          Concerning Underground Injection as  an remediation
          alternative at the Monsanto Company  Site.

       3. Memorandum from Robert E. Safay, Agency  for Toxic
          Substances and Disease Registry (ATSDR)  to James E.
          McGuire, EPA Region IV (August 28, 1990). Concerning
          review of the draft Feasibility Study Report  and the
          draft Risk Assessment.

       4. Memorandum from Roger E.  Carlton, EPA Region  IV
          Environmental Services Division, Athens,  Georgia  to
          James E. McGuire, EPA Region IV (August  28,  1990).
          Concerning review of the draft Feasibility Study
          Report for the Monsanto Company Site.

       5. Memorandum from Kevin P.  Koporec, EPA Region IV to
          James E. McGuire, EPA Region IV (August  31,  1990).
          Concerning review and comments on the draft
          Feasibility Study Report for the Monsanto Company Site,

       6. Memorandum from David W.  Hill, EPA Region IV to James
          E. McGuire, EPA Region IV (September 4,  1990).
         * Concerning review of the draft Feasibility Study
          Report for the Monsanto Company Site.

       7. Latter from George D. Rozelle, Monsanto Chemical
          Company to James E. McGuire, EPA Region IV (September
          14, 1990).  Concerning transmittal of the Final
          Feasibility Study Report (FS) and the Final Risk
          Assessment (RA) for the Monsanto Company Site in
          Augusta, Georgia.

       8. "Monsanto - Augusta Plant Site - Feasibility Study -
          Final Report," Dames & Moore  (September  16, 1990).

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DRAFT, 09/18/90, 16:14
Page 13
9.0
STATE COORDINATION
9.1
Correspondence

1~ Letter from James E. McGuire, EPA Region IV to
Jennifer Kaduck, Georgia Environmental Protection
Division (July 20, 1990). Concerning request for the
assistance of the State of Georgia in identifying
environmental standards applicable for the Monsanto
Company Site in Augusta, Georgia.
9.6
Cooperative Agreements, Special Conditions, and
Amendments
1. Letter from J. Leonard Ledbetter, Georgia
Environmental Protection Division to Fred Hiller,
Monsanto Chemical Company (June 8, 1984). Concerning
attached copy of Consent Agreement between the Georgia
Environmental Protection Division and Monsanto
Chemical Company.
10.0
ENFORCEMENT
10.6
State and Local Enforcement Records
1. Letter from George D. Rozelle, Monsanto Chemical
Company to J. Leonard Ledbetter, Georgia Environmental
Protection Division (December 28, 1983). Concerning
activities associated with the closure of the Monsanto
Company Site in Augusta, Georgia.

2. Letter from Bill Mundy, Georgia Environmental
Protection Division to George D. Rozelle, Monsanto
Chemical Company (January 26, 1984). Concerning
response to December 28, 1983 letter describing the
closure of MOnsanto Company Site.
10.10 PRP-Specific Negotiations

1. Cross-Reference: Letter from Stephen P. Krchma,
Monsanto Company to Gail S. Baylor, EPA Region IV
(February 7, 1989). Response to notice letter and
desire to participate in negotiations with EPA
regarding the Monsanto Company Site. [Filed and cited
as entry number 2 in 11.9 POTEN'l'IALLY RESPONSIBLE
PARTIES (PRP) - PRP-Specific Correspondence]
2. Letter from Stephen P. Krchma, Monsanto Chemical
Company to Gail S. Baylor, EPA Region IV (March 24,
1989). Concerning negotiations between EPA Region IV
and Monsanto Chemical Company.

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DRAFT, 09/18/90,  16:14                                   Page 14


   10.10 PRP-Specific Negotiations (cont'd.)

       3. Letter  from Gail S. Baylor, EPA Region IV to Stephen
          P. Krchraa, Monsanto Chemical Company (April 12, 1989).
          Concerning Good Faith Proposal and Draft
          Administrative Order by Consent.

   10.11 EPA Administrative Orders

       1. Cross-Reference:  Letter from Gail S. Baylor, EPA
          Region  IV to Stephen P. Krchina, Monsanto Chemical
          Company (April 12, 1989).  Concerning Good Faith
          Proposal and Draft Administrative Order by Consent.
          [Filed  and cited as entry number 3 in 10.10
          ENFORCEMENT - PRP-Specific Negotiations]

       2. Consent Order, IN THE MATTER OF MONSANTO COMPANY,
          AUGUSTA PLANT, P.O. BOX 1473, AUGUSTA, GEORGIA, Docket
          No. 89-24-C. (April 24, 1989).

11.0  POTENTIALLY RESPONSIBLE PARTIES (PRP)

   11.9  PRP-Specific Correspondence

       1. Letter  from Patrick M. Tobin, EPA Region IV to George
          D. Rozelle, Monsanto Company (January 18, 1989).
          Concerning notice of potential responsibility  for  the
          release or threaten release of hazardous substances
          and contaminants at the Monsanto Company Site  in
          Augusta, Georgia.

       2. Letter  from Stephen P. Kr china, Monsanto Company to
          Gail S. Baylor, EPA Region IV  (February 7, 1989).
          Response to notice letter and desire to participate  in
          negotiations with EPA regarding the Monsanto Company
          Site.

13.0  COMMUNITY RELATIONS

   13.6  Community Relations Plans
         =.
       1. "Revised Community Relations Plan - Monsanto
          Corporation," Booz, Allen & Hamilton, Inc.  for EPA
          Headquarters  (August 18, 1989).

   13.9  Fact Sheets

       1. "Superfund Remedial Investigation/Feasibility  Study -
          Fact Sheet - Monsanto Site - Augusta, Georgia,"
          (October 1989).

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APPENDIX B
RESPONSIVENESS SUMMARY
Monsanto Superfund Site
Augusta, Georgia

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                        MONSANTO SUPERFUND SITE
                         RESPONSIVENESS SUMMARY


 The U.S. Environmental Protection Agency (EPA) established a public
 comment period  from November 1, 1990 through November 30, 1990 for
 interested parties to comment on EPA's Proposed Plan for remediation
 of the Monsanto Superfund site.  The Proposed Plan was released to
 the public on October 30, 1990.  A public meeting was held on
 November 14, 1990, at the Augusta-Richmond County Library in Augusta,
 Georgia.  During the meeting the results of the studies undertaken at
 the site as well as EPA's preferred alternative was presented.

 A responsiveness summary is required by Superfund policy [40 CFR
 300.430 (f)(3)(i)(F)] to provide a summary of citizen comments and
 concerns about  the site raised during  the comment period, and the
 response by EPA to those concerns.  All comments summarized in this
 document have been factored into the final decision of the preferred
 alternative for remediation of the Monsanto Superfund site in
 Augusta, Georgia.

 This responsiveness summary is divided into the following sections:

    I.        Overview - This section  discusses the recommended
              alternative for remedial action and the public reaction
              to this alternative.

    II.       Background on Community  Involvement and Concerns - This
              section provides a brief history of community interest
              and concerns regarding the Monsanto Superfund site.

    III.      Summary of Major Questions and Comments Received During
              the Public Comment Period and EPA's Responses - This
              section presents both oral and written comments
              submitted during the public comment period and provides
              EPA's response to these  comments.

    IV.       Remaining Concerns - This section discusses community
              concerns of which EPA should be  aware in design and
              implementation of the remedial alternative for the
              site.


 I.   Overview

The preferred remedial alternative was presented to the  public  in  a
Proposed Plan released on October 30,  1990, a  public notice  in  the
Augusta Chronicle and Herald on November 1 and 12,  1990  as well as at
a public meeting held on November 14,  1990.  This alternative
includes extraction and discharge of the contaminated  groundwater  to

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2
the Augusta Wastewater Treatment Plant until the arsenic levels in
the groundwater attain the Max£mum Contaminant Level (MCL). During
the design of the extraction well system, groundwater quality will be
monitored on a quarterly basis. The initiation of the construction
phase may be deferred based on the results of the quarterly
monitoring. The major components of the alternative include:
*
Continue quarterly groundwater monitoring during the design
of the selected remedy to determine compliance with the
Groundwater Protection Achievement Levels (GPALs):
*
Should the annual average of the levels as determined
quarterly monitoring exceed the GPALs, extraction of
groundwater which exceeds the Pr£mary Drinking Water
Standard (ie., Max£mum Contaminant Level or MCL) for
will commence;
by the
arsenic
*
Discharge extracted groundwater for treatment at a Publicly
Owned Treatment Works (POTW):
*
Groundwater monitoring for a min£mum of two years following
the attainment of the MCL.
II.
Backaround on Community Involvement and Concern
A Community Relations Plan was prepared by EPA in December 1988. In
October 1989, EPA printed and distributed a fact sheet describing the
activities to be conducted during the Remedial Investigation and
Feasibility Study for the Monsanto site. An informal meeting was
held by EPA on October 20, 1989, at the Augusta-Richmond County
Library to address concerns the public may have had regarding the
site investigation.
An EPA prepared Proposed Plan which described alternative remediation
plans, along with EPA's preferred remedy, was mailed to the public
which had previously expressed an interest in the site on October 30,
1990. The Proposed Plan gave a brief site history, described the
Superfund process and the remedial alternatives, provided details
about the public comment period and the public meeting to be held on
November 14, 1990. In addition to the Proposed Plan, a public notice.
was published in the Augusta Chronicle and Herald on November 1, 1990
and November 12, 1990, to notify the public of the availability of
the Proposed Plan and the upcoming public meeting.
Environmental concerns are receiving increasing attention in the
Augusta area. A citizen group (Citizens Against Pollution or "CAP")
has been formed to monitor the activities of local industry and to
report potential problems to the proper authorities. Representatives
.f CAP met with the EPA's Remedial Project Manager for the Monsanto
site on November 13, 1990, to discuss the Superfund process and EPA's

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 activities  at  the Monsanto  site.  CAP representatives were given a
 tour of  the Monsanto  Superfund site on November 14, 1990.


 III.   Summary  of  Malor Questions and Comments Received During the
       Public Comment  Period and EPA's Responses

 Comment  1:  Several people were concerned with the potential
 interconnection between contamination at the Monsanto site and a
 property located  approximately one-half mile east of Monsanto.

 EPA's Response: A comparison of the data collected at the Monsanto
 site with data collected at the downgradient property does not appear
 to provide  a sufficient chemical "fingerprint" to support the
 potential interconnection between these two areas.  Specifically,
 numerous inorganics as well as xylene, present at elevated levels at
 the downgradient  property,  have not been detected at the Monsanto
 site.  Also, chromium levels at the downgradient property exceeded
 the concentrations of arsenic present in the groundwater at this
 property.   At  the Monsanto  site, the concentrations of the
 contaminant of concern, arsenic, far exceeds the chromium levels.
 This  differential in  concentration indicates separate potential
 sources  of  the contamination.

 In addition to the lack of  a chemical fingerprint, the results from
 the Remedial Investigation  (RI) indicates the entire plume relating
 to the Monsanto site  has been defined.  Data collected during the RI
 shows  increasing  to decreasing arsenic levels as the distance from
 the source  (landfill  #2) becomes greater.  Based on this data, the
 core  of  the plume is  currently located approximately 250 feet
 downgradient of the landfill.  Samples from a line of monitoring
 wells  located  400 feet downgradient from the core were all below the
 Federally regulated drinking water standard for arsenic of 50 ug/1.


 Comment  f2t There was concern that a model, rather than actual data
 from  sampling  done during the site investigation, was being relied on
 by EPA to select  a remedial alternative at the Monsanto  site.

 EPA's  Response: EPA has not relied solely on the model in selecting a
 remedy at this site,  but instead the model was used to supplement the
 results  from numerous sampling events.  Since the model was
 calculated  using  assumptions, it is used only to indicate or  project
 the potential  movement and  concentration of the arsenic  plume.  The
model  was calibrated  by comparing the existing data collected during
 the 1989 site  investigation with the results of the model for the
year 1990 (year ten from the model).  Based on this comparison, the
model  over  estimated  the extent of the plume.  The predicted  arsenic
concentrations will be verified as part of the selected  alternative
through quarterly groundwater monitoring.

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4
Comment #3: One person was concerned the modeling technique used
during the site investigation would not provide an accurate
representation of the potential migration of arsenic present in the
groundwater.
EPA's Response: During the study of the site, the Plume modeling
technique was used to project future transport of the arsenic plume.
This technique was used since the site is underlain by unconsolidated
sediments and only one contaminant, arsenic, was present at elevated
levels at the site. A detail discussion on the modeling effort is
provided in Section 5 of the Remedial Investigation Report. Prior to
the site investigation, a more complex modeling effort using the
Random-Walk technique was conducted. It should be noted that complex
models require more input data or assumptions, than models such as
Plume. However, both the Random-Walk and Plume models indicate
decreasing concentrations of arsenic to background levels as distance
from the source becomes greater. Groundwater samples obtained during
the site investigation support the model predictions.
Comment #4: A citizen asked why sampling results collected between
1987 through 1989 show an increase in arsenic levels.
EPA's Response: Groundwater sampling at the Monsanto site has been
conducted since 1979. Although the overall trend of the annual
average arsenic concentrations show a decrease, fluctuations of the
contaminant levels have been observed. Specifically, arsenic levels
increased during the period of time between 1987 through 1989. While
the exact cause for this increase is not known, the increase may have
been due to a drought Augusta was experiencing during this period.
With less rainfall to produce infiltration, there would be less
groundwater available to carry the dissolved arsenic, thus an
increase in concentration would be observed. The sampling results
from 1990 confirm the overall trend of decreasing arsenic
concentrations has continued to occur. Sampling results from the
last quarterly monitoring conducted in 1990 show all wells at the
site either at or near background levels.
- .
Comment #5: A commenter requested EPA account for the variability of
the arsenic levels when selecting the Groundwater Protection
Achievement Levels (GPALS).

EPA's Response: The GPALs have been established based on the modeled
projection of arsenic concentrations in MW-35. The GPALs also will
be monitored in the other contaminated well at the site (MW-17) since
this well is upgradient of MW-35. The fluctuation of contaminant
concentration has been considered in establishing the GPALs for these
wells. The GPAL for a specific year will be compared with the annual
~verage of the level from the quarterly groundwater monitoring
.rogram. Averaging the concentrations on an annual basis would

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minimize the potential  for noncompliance with the GPALs should
contaminant fluctuation occur during a single sampling event.


Comment #6; One commenter proposed the selection of a modified
version of Alternative  II which would establish "Interim Arsenic
Levels" rather than the "Interim Alternate Concentration Limit".

EPA's Response: When compared to the modified version of Alternative
II, Alternative III appears to provide the best balance among the
nine criteria used to evaluate alternatives.  The Interim Arsenic
Levels proposed by the  commenter allows much greater fluctuations in
arsenic concentrations  as well as time to achieve the drinking water
standard as does the selected remedy.  In addition, the selected
remedy requires the initiation of the design of the extraction well
system concurrent with  monitoring the compliance with the GPALs.
Noncompliance with the  GPALs would require the immediate initiation
of the construction phase of the remedy, thus minimizing the time
period migration of the plume could occur.  Alternative II requires
additional time to select and design an active method of remediation
should the proposed interim levels not be complied with.

EPA's selected alternative provides a greater degree of protection of
human health and the environment since treatment is relied upon to
eliminate potential exposure by actively remediating the groundwater
should noncompliance with the GPALs occur.  Implementability of the
selected alternative could potentially be more difficult than
commenter's proposed alternative due to the potential construction of
the extraction well system should GPALs not be achieved.  However,
the inconveniences relating to the construction is no trade off for
protection of human health and the environment.

Comment f7; A representative of a local citizen's environmental group
supported the proposal  of Alternative III; however, the
representative was concerned with the additional burden on the POTW
from the Monsanto site.

EPA's ResponseV The additional flow of wastewater to the POTW is not
anticipated to impact its operation.  The current mass of arsenic
being accepted by the POTW was calculated at 357 grams/day.  The
discharge from the Monsanto site to the POTW would increase the
current mass by approximately 8 grams /day.  The POTW treats the
wastewater through an activated sludge treatment process.  The  sludge
is recycled via land application.  At the current loading rate  (2.46
metric tons/ha), this sludge may contain over four times greater
arsenic than currently  present.  The arsenic levels from the Monsanto
site will not significantly increase the current concentration.

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6
IV.
Remainina Concerns
The community's concerns surrounding the Monsanto site will be
addressed through community relations support throughout the Remedial
Design/Remedial Action.
Community relations will consist of making available final documents
(ie., Remedial Design Workplan, Remedial Design Reports, etc.) in a
timely manner through the local repository. Also, issuance of fact
sheets, during the Remedial Design/Remedial Action process, to those
on the mailing list will further provide the community with project
progress and a schedule of events. The community will be made aware
of any principal design changes made during the project design as
well as the results of the quarterly groundwater monitoring.

Community relations activities will remain an active aspect of the
Remedial Design/Remedial Action phase of this project.

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APPENDIX C
STATE CONCURRENCE LETTER
Monsanto Superfund Site
Augusta, Georgia

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FROM:DNRE?D ADMIN ~G7
TO:
404 347 4464
DEC 7. 1990
10: 49AM
~.22
Geor.~ia Department of Natural Resources

20'S "Sutler Str;;~."S.t;.. FIOYd-To~-e-rs East: 'Atlanta: Georgia '30334
J. Leonerd Le\Jberrer Cumm,ss.un",r
HarOld F, Rch4l15. ASS'SI.1lnt D,reCtor
EnlllrO')1II4Intill ProtectIon Dlv's.un
December 3, 1990
Mr. Jim McGui re
Remedial Project Manager
Superfund Branch
US EPA Region IV
345 Courtland Street, N.E.
Atlanta, Georgia 30365
fiLE []py
RE:
Monsanto Chemical Company
Draft ROD
Dear Mr. McGuire:
We have reviewed the draft Record of Decision (ROD) for the Monsanto
Superfund site located in Augusta, Georgia. Sfnce you indicated that
references to the deconmissioning of groundwater monitoring wells have been
removed, we have no objections to Alternative 3 (pump and discharge) as
Monsanto's corrective action for the groundwater contamination from the two
landfills. However, when drafting Monsanto's pending hazardous waste pennit
modification, the Division is not limiting itself to certain time frames set
forth fn the draft ROD, therefore the requirements in the permft modification
may be more stringent.

Additiona1ly, the Division 1s continuing to investigate the contamination
of the nearby property owned by Norfol k Southern Corporat10n to detenni ne 1f
there ;s a link to the Monsanto NPL site.
Thank you for the opportunity to revi ew the draft ROD.
questions, p1ease contact Jan Simmons at 404/656-2833.

Sf ncerely,


~ay~O~~(.

Land Protection Branch
If you ha ve any
=
JDT:js:3395M
. fl1 e:
Monsa nto (R)

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