final - missouri department of natural resources plan-final-v8.pdf · proposed plan for scott afb...

Final

Proposed PlanScott Air Force Base Environmental Restoration Program

Site SS018, National Imagery and Mapping Agency,Second Street

National Geospatial-Intelligence Agency3200 South Second Street

Saint Louis, Missouri 63118

November 2018

Air Education & Training CommandContract No. FA3002-07-D-0015

Task Order No. 0013

Prepared by:AECOM

9400 Amberglen BoulevardAustin, Texas 78729

PROPOSED PLAN FOR SCOTT AFB ERP SITE SS018, SAINT LOUIS, MISSOURI

TABLE OF CONTENTS

1 INTRODUCTION .......................................... 1

2 SITE BACKGROUND ................................... 2

3 SITE CHARACTERISTICS ........................... 4

4 SUMMARY OF SITE RISKS ........................ 5

5 REMEDIAL ACTION OBJECTIVES ............ 5

6 SUMMARY OF ALTERNATIVES ................ 6

7 EVALUATION OF ALTERNATIVES ........... 7

8 PREFERRED ALTERNATIVE ...................... 8

9 COMMUNITY PARTICIPATION ................. 9

10 REFERENCES ............................................... 9

11 GLOSSARY OF TERMS ............................ 10

TABLES

Table 1 – Recommended Preliminary RemediationGoals

Table 2 – Alternative Comparative Analysis

FIGURES

Figure 1 –Site SS018 Location

Figure 2 – Site Layout and Features

Figure 3 – Approximate Excavation Limits andInstitutional Controls Boundaries for Alternatives 2,3, and 4

Figure 4 – Preferred Alternative

ACRONYMS

AECOM AECOM Technical Services, Inc.AFB Air Force BaseAMW Air Mobility WingARARs Applicable or Relevant and Appropriate

Requirementsbgs below ground surfaceCERCLA Comprehensive Environmental Response,

Compensation, and Liability ActCFR Code of Federal RegulationsCOC Contaminant of ConcernCOPC Chemical of Potential ConcernCR cancer riskCT Central TimeEBS Environmental Baseline SurveyEPA United States Environmental Protection

AgencyERP Environmental Restoration ProgramFS Feasibility Studyft feet, footHHRA Human-Health Risk AssessmentHQ hazard quotientMDNR Missouri Department of Natural

Resourcesmg/kg milligrams per kilogrammsl mean sea levelNA not applicableNCP National Oil and Hazardous Substances

Pollution Contingency PlanNGA National Geospatial-Intelligence

AgencyO&M operation and maintenancePAH polycyclic aromatic hydrocarbonsPCB polychlorinated biphenylsPCE perchloroethenePRG Preliminary Remediation GoalRAO Remedial Action ObjectiveRCRA Resource Conservation and Recovery

ActRI Remedial InvestigationROD Record of DecisionRSL Regional Screening LevelSAIC Science Applications International

CorporationSS018 Spill Site 018SVOC semivolatile organic compoundsTBD To Be DeterminedTPH total petroleum hydrocarbonsUSAF United States Air ForceUTL Upper Tolerance LimitVOC volatile organic compounds


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Proposed PlanScott Air Force Base

Environmental Restoration ProgramSite SS018,

National Imagery and Mapping Agency,Second Street

November 2018

1 INTRODUCTION

This Proposed Plan1 identifies Excavation andOffsite Disposal with Institutional Controls as thePreferred Alternative at the Scott AFBEnvironmental Restoration Program (ERP) SiteSS018 in Saint Louis, Missouri (see Figure 1). ThisProposed Plan provides the rationale for the selectionof this alternative and is issued by the United StatesAir Force (USAF), the lead agency for site activities.The USAF, in consultation with the MissouriDepartment of Natural Resources (MDNR), willselect the final remedial action for the site afterreviewing and considering all information submittedduring the public comment period and the publicmeeting. The USAF may modify the preferredalternative or select another remedial action, based onnew information or public comments. Therefore, thepublic is encouraged to review and comment on allthe remedial alternatives in this Proposed Plan.

The USAF is issuing this Proposed Plan as part of itspublic participation responsibilities under Section117(a) of the Comprehensive EnvironmentalResponse, Compensation, and Liability Act(CERCLA; 42 United States Code §9617(a)); andSection 300.430(f)(2) of the National Oil andHazardous Substances Pollution ContingencyPlan (NCP).

This Proposed Plan summarizes the site background,site characteristics, and site risks (Sections 2, 3, and4, respectively) that can be found in greater detail inthe Final Remedial Investigation Report for Site SS-18 (National Geospatial-Intelligence Agency Site)(CH2M HILL, July 2014a) (unless otherwise noted).

1 Boldfaced terms are defined in Section 11 -- Glossary ofTerms.

PUBLIC COMMENT PERIOD:November 30, 2018 – January 18, 2019

The USAF will accept written comments on the Proposed Planduring the public comment period. Comment letters must bepostmarked by January 18, 2019 and should be submitted to:

375th AMW Public AffairsAttn: Christine Spargur901 South Drive, Building 700 WestScott Air Force Base, Illinois [email protected]

To request an extension send a request in writing toMs. Spargur by January 18, 2019.

PUBLIC MEETING:The USAF will provide a public meeting to explain theProposed Plan. Oral and written comment swill also beaccepted at the meeting. The public meeting will be held at theSaint Louis Public Library, Carpenter Branch, 3309 SouthGrand Boulevard, Saint Louis, Missouri, 63118 on December17, 2018 from 6:30 PM – 8:30 PM, with a brief presentation at7:00 PM.

For more information, see the Administrative Record at thefollowing locations:

Southwestern Illinois College Public LibraryIS Room 10252500 Carlyle AvenueBelleville, Illinois 62221(618) 235-2700, ext. 5204Hours: Monday-Thursday, 8:00 a.m. to 8:00 p.m. CTFriday 8:00 a.m. to 4:00 p.m. CT

Scott Air Force Base (AFB)375th Civil Engineering Environmental OfficeAttn: Rodger Allison702 Hangar Road, Building 531Scott AFB, Illinois 62225-5035(618) 256-2926Hours: Monday-Thursday, 8:00 a.m. to 4:00 p.m. CT

http://afcec.publicadmin-record.us.af.mil/Select “Scott AFB, IL” in “Installation List” at left side ofpage. Then select “SS-18 National Imagery and MappingAgency” in “Sites” box and hit “Search.”

http://afcec.publicadmin-record.us.af.mil/


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The remedial action objectives (RAOs), summaryof remedial alternatives, and evaluation ofalternatives (Sections 5, 6, and 7, respectively) can befound in greater detail in the Final Feasibility StudyReport, Site SS-18, National Geospatial-IntelligenceAgency Site (CH2M HILL, July 2014b). The MDNRprovided comments on the remedial alternatives inJune 2018 which have been incorporated into thisProposed Plan.

These and other documents related to this site arecontained in the Administrative Record. The USAFencourages the public to review these documents togain a more comprehensive understanding of the siteand investigation activities that have been conducted.Public input to this Proposed Plan will bedocumented in a Record of Decision (ROD) thatidentifies the selected alternative.

2 SITE BACKGROUND

Site SS018 is located at the National Geospatial-Intelligence Agency (NGA), 3200 South SecondStreet, Saint Louis, Missouri 63118. The site iswithin the industrial area of the City of Saint Louisbetween Arsenal Street and Utah Street and East ofSouth 2nd Street (see Figure 1 and Figure 2).Neighboring industrial sites include Anheuser-Buschand Sigma Aldrich.

Operational History. The site was established in1827 as the Saint Louis Arsenal, and has been usedfor various activities over approximately the past 200years.

From 1827 to the Civil War, the original 37-acreproperty was established as a recruiting and ordnancedepot for the United States Cavalry, known as the“Saint Louis Arsenal.” The Saint Louis Arsenalinitially was used for assembling, storing, and issuingsmall arms, artillery, artillery shells, gun carriages,ammunition, gunpowder, and other accoutrements toUnited States Army troops and state militias. Alimestone quarry was created in 1827 in the northeastcorner to provide building stone for onsite structures,but historical site sketches from 1849 and beyond donot depict the quarry. The quarry may have beenused for waste disposal from 1831 or before until atleast the 1860s.

The current site was turned over to the WarDepartment in 1876 as a recruiting depot. In 1879, 7acres were transferred to the City of Saint Louis (nowLyon Park). In 1882, 6 acres were transferred to theUnited States Army Corp of Engineers. By 1890, theremaining artillery had reportedly been sold as scrapiron to local foundries. From about 1884 to 1922, the

remaining site served as a general quartermasterdepot. During World War I, the site became knownas the Saint Louis General Intermediate Depot. Itwas renamed the Saint Louis Medical IntermediateDepot, and later renamed the Saint Louis MedicalDepot.

After World War I, the Saint Louis Medical Depotwas established at the site in July 1922. Standardmedical, dental, veterinary, and x-ray supplies werestored and distributed, and medical furniture andequipment was repaired. During World War II(1939-1945), the Medical Supply Depot usedBuilding 36 as a quartermaster warehouse andmorgue. In 1943, instruments were shipped to theSaint Louis Medical Depot for electrochemicalprocessing to prevent corrosion of surgicalinstruments.

From 1952 to present time, the facility has been usedfor producing cartographic and imagery products andproviding imagery intelligence and geo-spatialinformation in support of national security objectives.The site was listed in the National Register ofHistoric Places on January 17, 1975. Scott AFB isthe real property owner.

Potential Environmental Impacts Based on HistoricalUses. Based on the activities conducted before 1950,generation of hazardous waste likely was relativelyminor. NGA has no records of hazardoussubstance/waste use, storage, and disposal before1980. Based on the available information ofchemicals and wastes formerly stored onsite,hazardous substances that may have been present atthe site include photo processing chemicals (silver,chromium), trichloroethene, solvents, paints,thinners, water treatment chemicals, industrialstrength cleaners, compressed gases, inks, toners,pesticides, petroleum products, heating oil and fuels,automotive wastes and materials, incineration wastes,and asbestos materials.

Environmental Investigation History. The site hasbeen the subject of numerous environmentalinvestigations which are summarized below.

In 1985, a Phase I records search was performed toidentify potential areas of environmental concernrelated to industrial operations, hazardous wastemanagement, and pesticide use. The study concludedthere was minimal potential for contamination frompast activities at the site.

From 1988 through 2005, there was a series ofenvironmental actions and investigations.


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· 1988. In response to a release of photochemicalwaste solutions in the subbasement of Section D ofBuilding 36, a soil removal action was performedinvolving approximately 6,000 pounds ofcontaminated soil.

· 1989. An Environmental Liability Assessmentwas performed which identified hazardous wastestorage areas, underground storage tanks, and alack of consistent record keeping anddocumentation of overall environmental issues.

· 1990. Nine soil samples were collected from thesubbasement of Building 36D and analyzed forResource Conservation and Recovery Act(RCRA) inorganics, cyanide, sulfides, sulfate,nitrate, and phosphate. There were no records thatthis sampling event led to a corrective action.

· 1999. A Federal Facility Preliminary Assessmentwas performed which identified potential sourcesof environmental contamination including aheating oil spill south of Building 12, waste oildisposal south of Building 36, pesticide storage atBuilding 2, paint storage at Building 7,photochemical and printing operations at Buildings36 and 37, fuel oil pipeline leaks, and leaks fromexisting and former underground storage tanks.The United States Environmental ProtectionAgency (EPA) notified the National Imagery andMapping Agency (now NGA) on 4 June 1999 ofthe requirement to complete further investigationof the facility.

· 1999. In October 1999, the subbasement ofBuilding 36D was inspected. There was standingwater from rainwater infiltration in about 5 percentof the subbasement. Other observations includedbroken and cut pipes associated with the floordrain system, an abandoned sump pump, and abroken subgrade pipe showing signs of significantcorrosion.

· 1999. A Phase I Environmental Baseline Survey(EBS) identified 10 areas needing furtherinvestigation to meet environmental due diligenceand to properly categorize the property accordingto United States Air Force Policy.

· 2001 and 2002. A Phase II EBS documented theperformance of geophysical surveys, installation of17 groundwater monitoring wells, and thecollection and laboratory analysis of 68 surfacesoil, 137 subsurface soil, and 17 groundwatersamples for volatile organic compounds (VOCs),semivolatile organic compounds (SVOCs)(including polycyclic aromatic hydrocarbons[PAHs]), total petroleum hydrocarbons (TPH),

pesticides, polychlorinated biphenyls (PCBs),target analyte metals, and other compounds.

· 2004. A Federal Facility Site Inspection reviewreport for EPA Region 7 indicated that althoughthe Phase II EBS identified additional areas ofinterest, it did not investigate them. The reviewconcluded that the Phase II EBS had minimal or noanalytical data for migration and exposurepathways associated with air, soil, groundwater,and surface water.

Between 2007 and 2010, the Remedial Investigation(RI) fieldwork was conducted in three phases whichconsisted of:

· Geophysical investigations;

· Installation of permanent overburden and bedrockgroundwater monitoring wells;

· Collection and laboratory analysis of surface andsubsurface soil samples;

· Collection and laboratory analysis of surface andsubsurface soil samples from the adjacent LyonPark to establish background (i.e., naturallyoccurring or anthropogenic) inorganic and SVOCconcentrations;

· Collection and laboratory analysis of groundwatersamples;

· Civil surveying; and

· Characterization and disposal of investigation-derived waste.

The RI, for the most part, delineated the nature andextent of contamination in soil (lead, chromium,pesticides, dioxins/furans, and PAHs) and groundwater(VOCs).

The RI report (CH2M HILL, July 2014a) concluded thePAHs in the soil likely are due to anthropogenicactivities throughout the industrial area of Saint Louis(e.g., asphalt parking lots and roadways, roofing tars).Several other factors were cited that included thepresence of fill material containing asphalt andmiscellaneous debris and the historic use of coal-powered equipment.

Some of the pesticide concentrations in soil detectedabove screening levels are likely related to historicalapplication of pesticides near existing buildings.However, pesticides were detected at higherconcentrations near areas where pesticides had beenstored (such as the former shed near the westernmostcorner of Building 2). Based on concentrationsdetected and distribution and site use, the RI report also


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concluded that the chromium and lead in soil may besite-related. Dioxins/furans in surface and subsurfacesoil exceeded their screening level and may be relatedto the historical operation of an incinerator.

Five VOCs were detected in groundwater atconcentrations above their screening levels. Three ofthe VOCs might be attributed to leaks in the City watersupply system (bromodichloromethane, chloroform,and dibromodichloromethane). The other two VOCsmay be related to historical solvent use (carbontetrachloride and perchloroethene [PCE]). In addition,two SVOCs (hexachlorobutadiene and bis[2-ethylhexyl]phthalate), one PAH (naphthalene), and fourinorganics (arsenic, total chromium, manganese, andthallium) were sporadically detected above theirrespective screening levels, but no potential sources ofcontamination are known.

In February 2018, in response to MDNR concerns thatthe RI did not sufficiently evaluate the potential for off-site migration of lead in soil (west of Building 40) andVOCs in groundwater (near the south corner of theproperty), AECOM Technical Services, Inc. (AECOM)conducted a limited subsurface investigation for soiland groundwater (AECOM, April 2018).

The soil investigation focused on evaluating the 1,390milligram/kilogram (mg/kg) detection of lead in soil ata depth of 5 feet (ft) beneath ground surface (bgs) insample SBAG104 collected in September 2007. Eightboreholes were advanced within 20 ft of SBAG104, butdue to borehole collapses and auger refusal, only threeboreholes were sampled at a depth of approximately 5ft bgs. The analytical results did not confirm leadconcentrations in soil approaching 1,390 mg/kg (asobserved in 2007), but rather demonstrated theexposure point concentration of lead in soil in this areawas less than the risk-based screening level (400mg/kg). Field observations and analytical results alsosupport the conclusion that lead concentrations arerelated to approximately 4 ft of urban fill material(containing various construction debris and blackcinders resembling ash material) in this portion of thesite.

The groundwater investigation focused on collectinggroundwater samples from four existing wells in thesouthern corner of the site which were analyzed forVOCs. The groundwater analytical results did notcontain any detected VOCs exceeding drinking waterstandards; chloroform was the only detected VOCexceeding residential tap water regional screeninglevels (RSLs), but from a well located in the interior ofthe site. Analytical results in the perimeter wells alongthe site boundary were all lower than drinking waterstandards and RSLs signifying a lack of potential off-site migration (AECOM, April 2018)..

3 SITE CHARACTERISTICSSite SS018 topography has been significantly alteredfrom its natural state. A letter from 1837 indicatedthat “The inequalities of the ground included withinthe buildings to be constructed, require cutting downand filling with earth drawn from a distance…”. Thesurface elevation of the site ranges from about 420 ftabove mean sea level (msl) along the southeasternedge of the property to 444 ft above msl along thenorthwestern edge of the property.

There are no surface waterbodies onsite. The soiloverburden ranges in depth from 4 to 33 ft bgs andconsists of fill placed over loess and Mississippialluvium. The loess is of glacial-fluvial origin andtypically about 80 percent silt and 20 percent clay.The alluvial soils are predominantly sand and finegravel, deposited, eroded, and redeposited overthousands of years. Sand layers of varyingthicknesses observed at several soil borings do notappear to be laterally continuous.

The local shallow groundwater aquifer consists ofalluvial deposits and the underlying limestonebedrock. The depth to groundwater ranges fromroughly 7 to 18 ft bgs. Because of the low waterquality, very few wells have been drilled within thearea limits of the City of Saint Louis. City-supplieddrinking water is provided to residents and industriesin the area. The city draws water from theMississippi River from intakes upstream of the site.

Effective 1 August 2005, Saint Louis City enactedOrdinance 66777 which prohibits the use orattempted use of groundwater as a potable watersupply and the drilling or installation of wells for apotable water supply within the corporate limits ofthe City of Saint Louis. In the unlikely event thatOrdinance 66777 is repealed, potential future use ofgroundwater as a potable water supply at the site wasevaluated using MDNR and EPA guidance. Theseevaluations considered numerous factors includingavailability of alternate water supplies and suitabilityof use based on total dissolved solids and yieldcriteria. The evaluations determined the groundwaterhas limited yield and poor quality, and an alternativewater supply (the Mississippi River) is readilyavailable as a current source of domestic watersupply. The evaluations concluded that the water-bearing zone at the site is not a reasonable future useas a domestic water supply.

According to the City of Saint Louis Strategic LandUse Plan, the property’s strategic land use is“Business and Industrial Preservation andDevelopment Area” (Saint Louis Planning and UrbanDesign Agency, 2005). The site covers about 22acres and consists of approximately 15 buildings,


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paved parking areas, traffic ways, and walkways (notincluding the railroad right-of-way) (Figure 2). It iscurrently used as a facility that provides imageryintelligence and geospatial information in support ofnational security objectives. The reasonablyanticipated future land use of the site iscommercial/industrial.

4 SUMMARY OF SITE RISKS

It is the lead agency’s current judgment that thePreferred Alternative identified in this Proposed Plan,or one of the other active measures considered in theProposed Plan, is necessary to protect public healthor welfare or the environment from actual orthreatened releases of hazardous substances into theenvironment.

Human Health Risks. The Human Health RiskAssessment (HHRA) considered the followingpotential human receptors: current and future onsiteindoor and outdoor workers, future construction/utility workers, future onsite residents, and currentand future offsite indoor workers and residents. Thesite was subdivided into exposure areas and exposurepoint concentrations were calculated for eachchemical of potential concern (COPC). Potentialexposures to surface soil (0 to 1 ft bgs) and total soil(0 to 10 ft bgs) were evaluated separately. Thepotential risks to human health were then calculatedbased on the potential exposures to each receptor andthe toxicity of the COPC. The contaminants ofconcern (COC) causing the unacceptable potentialrisks, and their associated areas and receptors, are asfollows:

· Pesticides and inorganics - Building 2 surface andtotal soil, future construction/utility workersand/or future residents;

· Thallium - Building 36D surface and total soil,future residents;

· PAHs - remaining sitewide area surface soil, futureresidents; and

· Lead – future scenarios only:

o Buildings 4 and 5 surface soil, futureindoor/outdoor workers, future construction/utility workers, and future residents;

o Buildings 4 and 5 total soil, futureconstruction/utility workers and future residents;

o Former Buildings BB and N surface soil, futureconstruction/utility workers;

o Former Buildings BB and N total soil, futureindoor/outdoor workers, future construction/utility workers, and future residents; and

o Former landfill quarry total soil, futureindoor/outdoor workers, future construction/utility workers, and future residents.

Ecological Risks. A screening level ecological riskassessment was also performed. The conclusionswere that due to a lack of suitable habitat and thehigh level of human disturbance, significant exposurepathways to ecological receptors are incomplete, andecological risks are therefore considered negligible.

5 REMEDIAL ACTION OBJECTIVESThe following RAOs were developed based on thecontaminant levels and exposure pathways found topresent potentially unacceptable risk to human healthas determined during the RI:

· Prevent direct human contact with and ingestionand inhalation of lead and thallium in soils up to10 ft bgs by future residents, future indoor/outdoorworkers, and future construction/ utility workersthat could result in an unacceptable human healthrisk as determined by the HHRA.

· Prevent direct human contact with and ingestionand inhalation of arsenic, chromium, and thallium

What are the “Contaminants of Concern”?

Arsenic, chromium, lead, and thallium areinorganics that were detected in site soil atconcentrations higher than naturally-occurring(background) levels. These and other metals arecommon contaminants in areas where industrialactivities have been conducted, such asmanufacturing, metal parts cleaning, fossil fuelburning, and photo processing.

PAHs include benzo(a)anthracene,benzo(a)pyrene, benzo(b)fluoranthene, anddibenz(a,h)anthracene. They are formed duringthe incomplete burning of fossil fuels and foundin vehicle exhaust, smoke, coal tar, and creosote.Low levels are typically found in urban surfacesoils including those collected in Lyon Park aspart of the study to determine background levelsof metals.

Pesticides are manufactured chemicals andinclude alpha-chlordane, gamma-chlordane,heptachlor, and heptachlor epoxide. As would beexpected, they are used to control pests such asrodents or insects. Pesticides properly applied fortheir intended purposes are not subject to cleanup,but levels associated with potential spills orunintended releases are subject to cleanup.


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in soils up to 10 ft bgs by future residents andfuture construction/ utility workers that couldresult in an unacceptable human health risk asdetermined by the HHRA.

· Prevent direct human contact with and ingestionand inhalation of PAHs benzo(a)anthracene,benzo(a)pyrene, benzo(b)fluoranthene, anddibenz(a,h)anthracene in soils up to 1 ft bgs byfuture residents that could result in an unacceptablehuman health risk as determined by the HHRA.

· Prevent direct human contact with and ingestionand inhalation of pesticides alpha-chlordane,gamma-chlordane, heptachlor, and heptachlorepoxide in soils up to 10 ft bgs by future residentsand future construction/utility workers that couldresult in an unacceptable human health risk asdetermined by the HHRA.

Recommended preliminary remediation goals(PRGs) for each COC and exposure pathway areprovided in Table 1. The PRGs are based upon site-specific risk based calculations, background uppertolerance limits (UTLs), and EPA RSLs. TheFeasibility Study (FS) did not identify any COCs forcurrent or future exposure pathways for groundwaterand current exposure pathways for soil; therefore, noPRGs for groundwater and current soil exposurepathways are identified.

6 SUMMARY OF ALTERNATIVESRemedial technologies were identified and screenedfor effectiveness, implementability, and relative cost.The technologies retained were developed into fourremedial alternatives.

Alternative 1 – No Action.

Estimated Capital Cost: $0

Estimated Operation and Maintenance (O&M)Cost: $90,000

Estimated Total Present-Worth Cost: $69,000

Estimated Time to Achieve RAOs: NotApplicable (NA)

The NCP requires that a no action alternative beevaluated as a baseline of comparison to otherapproaches. The no action alternative would leaveaffected soil in place at the site with no institutionalcontrols.

Alternative 2 – Institutional Controls.

Estimated Capital Cost: $21,000

Estimated O&M Cost: $334,000

Estimated Total Present-Worth Cost: $313,000

Estimated Time to Achieve RAOs: < 1 year

This alternative has the following main components:

- Implement institutional controls as administrativecontrols (e.g., land use controls) into a facilitymanagement plan;

- Conduct institutional control inspections andprepare inspection report annually;

- Abandon groundwater monitoring wells;

- Conduct 5-year reviews.

Institutional controls would be implemented in areaswhere exposure to COCs in soil would pose a potentialhuman health risk as defined by the RAOs. Figure 3depicts the areas that would be subject to institutionalcontrols and the COCs that present the unacceptablerisk for each area. For cost estimating purposes, it isassumed that these actions would be conducted over aperiod of 30 years.

The institutional controls as shown in the FinalFeasibility Study (CH2M HILL, July 2014b) weremodified in the Proposed Plan to address MDNRconcerns. Specifically, the institutional control toprevent residential development would be applied tothe entire Building 36D footprint instead of discreteportions of the building. Although the population ofchromium results from Building 36D were notstatistically different from background levels at LyonPark, there remains the possibility of discrete areas ofchromium contamination associated with thephotochemical laboratory at this building that couldhave used potassium dichromate which containshexavalent chromium.

In addition, Saint Louis City Ordinance 66777prohibits the use of groundwater as a potable watersupply within the corporate limits of the City of SaintLouis (including the Site SS018). The RI alsodetermined that the shallow groundwater formation atthe site did not have a sufficient yield to support useas a potable water supply and therefore was not areasonable potential future domestic water supply.To ensure the shallow groundwater at the site will notbe used in this manner in the future, the Air Forcewould incorporate an institutional control preventingpotential future groundwater use into the Scott AFBInstallation Development Plan.


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Finally, the institutional controls would beimplemented in accordance with the Sample FederalFacility Land Use Control ROD Checklist withSuggested Language (LUC Checklist) (EPA, 4January 2013).

Alternative 3 – Excavation and Offsite Disposalwith Institutional Controls.

Estimated Capital Cost: $912,000


Estimated Total Present-Worth Cost: $1,239,000

Estimated Time to Achieve RAOs: 1 year

Soil having COC-concentrations exceeding PRGs forfuture construction/utility workers and future indoor/outdoor industrial workers would be excavated up to adepth of 10 ft. The total estimated area to be excavatedwould be 50,000 square feet with an estimated volumeof 1,900 cubic yards (see Figure 3). The excavated soilwould be transported, treated as needed to meet landdisposal restrictions, and disposed of in a certifiedRCRA Subtitle D landfill (which is regulated by Title40 Code of Federal Regulations [CFR] Parts 239-259).Any soil classified as hazardous would be disposed ofat a certified RCRA Subtitle C landfill (which isregulated by Title 40 CFR Parts 260-273). Theexcavated areas would be backfilled with clean materialand restored to pre-excavation conditions (e.g.,concrete, asphalt, grass).

Institutional controls in Alternative 3 are the same asdescribed in Alternative 2. These controls would beimplemented to limit exposure to COC concentrationsleft in soil that pose a potential human health risk to thefuture resident, and include annual inspections,monitoring well abandonment, and 5-year reviews. Forcost estimating purposes, it is assumed that theseactions would be conducted over a period of 30 years.

Alternative 4 – Excavation and Offsite Disposal.

Estimated Capital Cost: $2,062,000


Estimated Total Present-Worth Cost: $2,157,000

Estimated Time to Achieve RAOs: 1 year

Alternative 4 is similar to Alternative 3 except soil withCOC-concentrations exceeding PRGs for all potentialreceptors defined in the RAOs would be excavated upto a depth of 10 ft bgs. The total estimated area to beexcavated would be 120,000 square feet with anestimated volume of 5,000 cubic yards (see Figure 3).The excavated soil would be transported, treated asneeded to meet land disposal restrictions, and disposedof in a certified RCRA Subtitle D landfill. Any soilclassified as hazardous would be disposed of at a

certified RCRA Subtitle C landfill. The excavatedareas would be backfilled with clean material andrestored to pre-excavation conditions (e.g., concrete,asphalt, grass).

Monitoring wells would also be abandoned, but noinstitutional controls, annual inspections, or 5-yearreviews would be warranted because all contaminatedsoil posing an unacceptable risk would be removed.

7 EVALUATION OFALTERNATIVES

Nine criteria are used to evaluate the differentremediation alternatives individually and against eachother to select a remedy in accordance withCERCLA. This section of the Proposed Plan profilesthe relative performance of each alternative againstthe nine criteria, noting how it compares to the otheroptions under consideration.

The nine criteria fall into three groups: thresholdcriteria, primary balancing criteria, and modifyingcriteria. A description of the purposes of the threegroups follows:

· Threshold criteria are requirements that eachalternative must meet to be eligible for selection.An alternative that does not meet a thresholdcriterion need not be retained for further analysisagainst balancing criteria.

· Primary balancing criteria are used to weigh majordifferences between alternatives.

· Modifying criteria may be considered to the extentthat information is available during the FS, but canbe fully considered only after public comment isreceived on the Proposed Plan.

The final remedy is selected based on weighing thedifferences identified during analysis of the balancingcriteria and any modifying criteria identified after theProposed Plan is issued.

The evaluation of the alternatives against the nineevaluation criteria is summarized in the followingparagraphs. A scoring of each alternative against thenine evaluation criteria is presented in Table 2. The“Detailed Analysis of Remedial Alternatives” can befound in the FS (CH2M HILL, July 2014b).

1. Overall Protection of Human Health and theEnvironment. The No Action Alternative(Alternative 1) does not mitigate the identified risksto human health or the environment. Alternative 1does not meet this threshold criterion and is thereforenot eligible for selection.

Alternatives 2, 3, and 4 would be protective butachieve protectiveness using different approaches.


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Alternative 2 would rely solely upon institutionalcontrols to prevent exposure of contaminated soil topotential receptors. Alternative 3 would remove themore highly contaminated soil posing a risk to futureconstruction/utility and industrial workers, and relyon institutional controls to protect future residentsfrom exposure to the lower contamination levels leftin place. Alternative 4 would remove all contami-nated soil thereby preventing all potential futureexposures and not require any institutional controls.

2. Compliance with ARARs. Potential ARARs includelocation-specific ARARs for archeological andhistoric preservation, as well as action-specificARARs for the management of excavated soil andstorm water during excavation activities. Nochemical-specific ARARs were identified; instead,PRGs are based on risk-based criteria andbackground concentrations. Alternatives 2, 3, and 4would each comply with ARARs. Alternative 1would not comply with ARARs.

3. Long-term Effectiveness and Permanence. Theaction of excavating contaminated soil, treating (asneeded), and disposing in a permitted landfillprovides for greater long-term effectiveness andpermanence than institutional controls. Accordingly,Alternative 4 provides the maximum level of long-term effectiveness and permanence, followed byAlternative 3 (combination of excavation andinstitutional controls), and Alternative 2 (institutionalcontrols only). Alternative 1 provides no long-termeffectiveness or permanence.

4. Reduction of Toxicity, Mobility, or Volume ofContaminants through Treatment. Alternatives 3 and4 are similar in that they would place excavated soilin a permitted landfill which would reduce thepotential mobility of contaminants in soil. Inaddition, treatment of the excavated soil would beprovided as needed to comply with land disposalrestrictions. Alternatives 1 and 2 would provide noreduction of toxicity, mobility, or volume ofcontaminants through treatment.

5. Short-Term Effectiveness. Alternative 2 could beimplemented the fastest and would not potentiallyexpose workers or the community to contaminationand therefore has the highest level of short-termeffectiveness. Excavation activities in Alternatives 3and 4 would require approximately 1 year toimplement and has the potential to expose workersand the community to contaminated media (e.g., toairborne dust), and result in contaminated stormwater runoff. However, protective measures wouldbe taken to minimize the potential for these adverseeffects. Alternative 1 would not be protective oreffective in the short-term.

CERCLA NINE EVALUATION CRITERIATHRESHOLD CRITERIA

1. Overall Protectiveness of Human Health and theEnvironment determine whether an alternative eliminates,reduces, or controls threats to public health and theenvironment through institutional controls, engineeringcontrols, or treatment.2. Compliance with Applicable or Relevant andAppropriate Requirements (ARARs) evaluates whetherthe alternative meets federal and state environmentalstatutes, regulations, and other requirements that pertain tothe site, or whether a waiver is justified.

PRIMARY BALANCING CRITERIA3. Long-term Effectiveness and Permanence considersthe ability of an alternative to maintain protection of humanhealth and the environment over time.4. Reduction of Toxicity, Mobility, or Volume ofContaminants through Treatment evaluates analternative’s use of treatment to reduce the harmful effectsof principal contaminants, their ability to move in theenvironment, and the amount of contamination present.5. Short-Term Effectiveness considers the length of timeneeded to implement an alternative and the risks thealternative poses to workers, residents, and the environmentduring implementation.6. Implementability considers the technical andadministrative feasibility of implementing the alternative,including factors such as the relative availability of goodsand services.7. Cost includes estimated capital and annual operationsand maintenance costs as well as present-worth cost.Present-worth cost is the total cost of an alternative overtime in terms of today’s dollar value. Cost estimates areexpected to be accurate with a range of +50 to -30 percent.

MODIFYING CRITERIA8. USAF as the Lead Agency and EPA and/or State asthe Support Agency(ies) Acceptance considers whetherthe MDNR agrees with the analyses and recommendationsof the USAF, as described in the RI/FS and Proposed Plan.9. Community Acceptance considers whether the localcommunity agrees with the analyses and recommendationsof the USAF. Comments received on the Proposed Planare an important indicator of community acceptance.

6. Implementability. Alternatives 1 and 2 areconsidered readily implementable, althoughAlternative 1 is not expected to be administrativelyfeasible. Alternatives 3 and 4 include excavationwhich is a conventional remedial approach withequipment and materials being readily available.However, conducting the excavations in a highlysecured area is more complicated. The highconcentration of underground utilities and heavysecurity limits the implementability of Alternatives 3and 4.

7. Cost. Each of the alternatives were evaluated interms of estimated capital costs, periodic O&M costs,and total present-worth costs. The followingsummarizes the estimated present-worth cost for eachalternative:


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· Alternative 1: $69,000· Alternative 2: $313,000· Alternative 3: $1,239,000· Alternative 4: $2,157,000

8. State/Support Agency Acceptance. The MDNRcomments on the Final FS (CH2M HILL, July2014b) have been incorporated into this ProposedPlan and the MDNR supports the PreferredAlternative (Alternative 3 with modifications).

9. Community Acceptance. Community acceptanceof the Preferred Alternative will be evaluated afterthe public comment period ends and will bedescribed in the ROD.

8 PREFERRED ALTERNATIVEThe Preferred Alternative for the Site SS018 isAlternative 3 (see Figure 4). The PreferredAlternative can change in response to publiccomment and new information.

Based on information currently available, the USAFbelieves the Preferred Alternative meets the thresholdcriteria and provides the best balance of tradeoffsamong the other alternatives with respect to thebalancing and modifying criteria. The USAF expectsthe Preferred Alternative to satisfy the followingstatutory requirements of CERCLA §121(b): (1) beprotective of human health and the environment, (2)comply with ARARs, (3) be cost-effective, (4) utilizepermanent solutions and alternative treatmenttechnologies or resource recovery technologies to themaximum extent practicable, and (5) satisfy thepreference for treatment as a principal element.

9 COMMUNITY PARTICIPATIONThe USAF and the MDNR provide informationregarding the cleanup of Site SS018 to the publicthrough public meetings; the Administrative Recordfile for the site; and announcements published in theSaint Louis Post-Dispatch and the Command Post(Scott AFB, Illinois). The USAF and MDNRencourage the public to gain a more comprehensiveunderstanding of the site and the remedial activitiesthat have been conducted at the site.

The dates for the public comment period; the date,location, and time of the public meeting; and thelocations of the Administrative Record files areprovided in the Introduction (Section 1) of thisProposed Plan.

The USAF will review the public’s comments as partof the process in reaching a final decision on the mostappropriate action to be taken.

10 REFERENCESAECOM, April 2018. Supplemental RI TechnicalMemorandum, Limited Subsurface Investigation forSite SS018 (National Geospatial-Intelligence AgencySite), Project Number VDYD20157602, ContractNumber FA3002-07-D-0015.

CH2M HILL, July 2014a. Final RemedialInvestigation Report, Site SS-18 (NationalGeospatial-Intelligence Agency Site), Saint Louis,Missouri, Project No. VDYD20097132, AFCEEContract No. FA8903-08-D-8769, Task Order 0171.

CH2M HILL, July 2014b. Final Feasibility StudyReport, Site SS-18, National Geospatial-IntelligenceAgency Site, Contract Number FA8903-08-D-8769,Task Order 0171.

EPA, 4 January 2013. Sample Federal Facility LandUse Control ROD Checklist with SuggestedLanguage (LUC Checklist), OSWER Directive9355.6-12.

Saint Louis Planning and Urban Design Agency,2005. Strategic Land Use Plan.

Science Applications International Corporation(SAIC), January 2011. Final Soil BackgroundEvaluation Report for Site SS-18 (NationalGeospatial-Intelligence Agency Site), Project NumberVDYD20087132A, Contract Number FA8903-08-D-8779, Task Order 0033.

For further information on Site SS018, pleasecontact:

Paul TakácsRemedial Project Manager

618-229-0782

Christine SpargurPublic Affairs Officer

618-256-4241

National Geospatial-Intelligence Agency3200 South Second Street

Saint Louis, Missouri 63118

Andrew HarrisRemedial Project Manager

573-751-6838Missouri Department of Natural Resources


Page 10

11 GLOSSARY OF TERMSAdministrative Record: A compilation of alldocuments relied upon to select a remedial actionpertaining to the investigation and remediation of theproject site.

Applicable or Relevant and AppropriateRequirements (ARARs): Substantive requirementsof state and federal status that regulate specificenvironmental contaminants, locations, or remedialactions to ensure protection of human health and theenvironment.Chemicals of Potential Concern (COPC): COPCsare organic compounds or metals that are present inenvironmental media at a site and the subject ofevaluation for nature and extent of contamination andassociated risks to human health or the environment.

Contaminants of Concern (COC): COCs areCOPCs that are present in affected environmentalmedia at a site at concentrations that pose a potentialrisk to human health or the environment and areincluded in the RAOs.

Comprehensive Environmental Response,Compensation, and Liability Act (CERCLA,otherwise known as Superfund): A federal law thatestablishes a comprehensive framework to identify,investigate, and clean up releases or threated releasesof hazardous substances, pollutants, or contaminantsinto the environment. CERCLA is codified in Title42 United States Code, Sections 9601-9675.

Feasibility Study (FS): The phase in theCERCLA/NCP cleanup process that evaluatesremedial technologies and alternatives to addresscontamination delineated in the RI to protect humanhealth and the environment.

Institutional Controls: Controls which seek torestrict potential human exposure to contaminatedmedia. Common institutional controls includefencing or administrative controls (e.g., land userestrictions) that prevent residential use of theproperty.

National Oil and Hazardous Substances PollutionContingency Plan (NCP): The NCP is the primaryregulation of CERCLA. The NCP is the Federalgovernment's procedures for responding to both oilspills and hazardous substance releases. The NCP iscodified in Title 40 CFR Part 300.

Preferred Alternative: The remedial action that,when compared to other potential remedial actions,was determined to best meet the CERCLA evaluationcriteria and is proposed for implementation at a site.

Preliminary Remediation Goal (PRG): PRGs arechemical-specific concentration goals that are

protective for anticipated receptors. PRGs helprefine the RAOs and are used to define the extent ofcontaminated media requiring remedial action. Forthis site, the PRGs are based on site-specific riskcalculations, RSLs, and background concentrations.Proposed Plan: A plan that identifies the preferredremedial action for a site, and is made available to thepublic for comment.

Record of Decision (ROD): The USAF uses theterm “Record of Decision” for the documentation ofremedial response decisions. Concurrence on theROD by the MDNR is sought and the USAFapproves the documentation.Regional Screening Levels (RSLs): RSLs are risk-based concentrations derived from standardizedequations combining typical exposure levels withEPA toxicity data. RSLs are considered by the EPAto be protective for humans (including sensitivegroups) over a lifetime and are periodically updated(often several times per year). Current RSLs forapproximately 800 contaminants and past updatescan be found at the following web address:https://www.epa.gov/risk/regional-screening-levels-rsls

Remedial Investigation (RI): The phase in theCERCLA/NCP cleanup process during whichcontaminant source(s) are identified andcharacterized and the nature and extent ofcontamination on impacted environmental media isdetermined.

Remedial Action Objectives (RAOs): The siteconditions to be achieved following completion ofthe remedial action with respect to site-specific COCsand maximum residual concentrations in theimpacted environmental media.

Resource Conservation and Recovery Act(RCRA). A federal law that creates the frameworkfor the proper management of hazardous and non-hazardous solid waste. The law describes the wastemanagement program mandated by Congress thatgave EPA authority to develop the RCRA program.RCRA is codified in Title 42 United States Code,Sections 6901-6992k.

Upper Tolerance Limit (UTL): Calculated statisticthat represents the upper end of the backgroundconcentrations for a COPC. Site concentrationslower than background UTLs are considered to bewithin background and not a result of site activities.


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Table 1Recommended Preliminary Remediation Goals

Location COCResidents

Construction Worker/UtilityWorkers Indoor/Outdoor Workers

PRG (mg/kg) Basisa PRG (mg/kg) Basisa PRG (mg/kg) BasisBuilding 2 alpha-Chlordane 8.8 HQ = 0.25 5.5 HQ = 0.33 NA NA

gamma-Chlordane 8.8 HQ = 0.25 5.5 HQ = 0.33 NA NAHeptachlor 7.6 HQ = 0.25 NA NA NA NAHeptachlor epoxide 0.02 HQ = 0.25 1.0 HQ = 0.33 NA NAArsenic 7.8 Backgroundc NA NA NA NATotal chromiumb 17 Backgroundc NA NA NA NAHexavalent chromiumb 6.3 EPA RSL NA NA NA NAThallium 0.78 HQ = 1 NA NA NA NA

Building 36D Thallium 0.78 HQ = 1 NA NA NA NARemaining Sitewide Area Benzo(a)anthracene 2.8 Backgroundc NA NA NA NA

Benzo(a)pyrene 2.4 Backgroundc NA NA NA NABenzo(b)fluoranthene 2.3 Backgroundc NA NA NA NADibenz(a,h)anthracene 0.19 CR = 1E-05 NA NA NA NA

Buildings 4 and 5 Lead 400 EPA RSL 800 EPA RSL 800 EPA RSLFormer Building BB and N Lead 400 EPA RSL 800 EPA RSL 800 EPA RSLFormer landfill quarry Lead 400 EPA RSL 800 EPA RSL 800 EPA RSL

a The target HQ was adjusted by the number of chemicals with the same target organ so that the total exposure to the COCs at the PRG level would not result in a hazardindex to a target organ above 1.

b It was assumed that chromium in the exposure media are present as hexavalent chromium because of the lack of specific analyses of the speciated forms of chromium atBuilding 2. Although there is a lack of analyses of the speciated forms of chromium at this site, a separate PRG is also provided for hexavalent chromium to better ensureprotectiveness.

c Background values based on 95/95 upper tolerance limit (UTL) presented in the Soil Background Evaluation Report (Science Applications International Corporation[SAIC], January 2011). The UTLs represent 95% coverage with 95% confidence (i.e., 95% of background concentrations are expected to be lower than the UTL with alevel of confidence of 95%).

COC = Contaminant of ConcernCR = cancer risk (1E-05 signifies a cancer risk of 1 in 100,000)EPA RSL - United States Environmental Protection Agency Regional Screening LevelHQ = hazard quotientmg/kg = milligram per kilogram (concentration)NA = not applicable because chemical is not a COC for receptorPRG = Preliminary Remediation Goal


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Table 2Alternative Comparative Analysis

Criteria

Alternatives

CriteriaType 1. No Action

2. InstitutionalControls

3. Excavation andOffsite Disposal withInstitutional Controls

4. Excavation andOffsite Disposal

Thre

shol

d Overall protection of human health and theenvironment

1 2 4 4

Compliance with ARARs 1 3 3 3

Bal

anci

ng

Long-term effectiveness and permanence 1 2 3 4

Reduction of toxicity, mobility, or volumethrough treatment

1 1 2 2

Short-term effectiveness 1 4 3 3

Implementability 4 4 1 1

Cost 4 3 2 1

Mod

ifyin

g State Acceptance 1 2 4 3

Community Acceptance TBD TBD TBD TBD

Current Total Score 14 21 22 21

ARARs = Applicable or relevant and appropriate requirementsScoring: 1 = poor; 2 = satisfactory; 3 = good; 4 = excellentTBD = To be Determined (during public review period)

ANHEUSER-BUSCHBREWERY

ANHEUSER-BUSCHTRUCK TERMINAL

SIGMA ALDRICH(CHEMICAL PROCESS)

MANUFACTURERS RAILWAY CO.(RAIL YARD)

UNITED STATES ARMYCORPS OF ENGINEERS

ST. LOUIS REFRIGERATORCAR CO. (STORAGE)

SITE SS018 LOCATIONLYON PARK

CITY OF ST.LOUIS

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Client/Site:Air Force - Scott Air Force Base Site SS018

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