MERITS OF LEACHINGAND MODELING STUDIES

Presented For:

USEPA REGION IIIand

PADER

Presented By:

Parsons Engineering Science, Inc.

On behalf of the

Jacks Creek/Sitkin Smelting Superfund SitePRP Group

*

•May 31, 1995

. AR303575

MEETINGOBJECTIVES

Agree on objectives and scopefor PRPs proposal to conductmodeling and leaching studiesto support the PRPrecommended site remedyReview and discuss RCRAconcerns associated with thePRP proposed remedyEstablish a schedule of activitiesleading to issuance of a ROD

NOTES:

AR303576

NOTES:

PROJECT HISTORY

• Sitkin smelting operation - 1958through 1977

• Krentzman purchases site forscrap metal recycling

• Site listed on NPL in 1989• Six site investigations - 1977through 1990

• Emergency response actions -1990 through present

• USEPARI/FS- 1993• PRP addendum FS - 1995

AR303577

SITECHARACTERIZATION

Qroundwater is present at about20 to 30 ft below ground level

*~~~̂ iAll potential groundwater ^receptors are upgradient except /the Krentzman well _^JGroundwater flow is towardJack's Creek (away fromreceptors)Low linear groundwater flowvelocity (.0001 to .000001 ft/min)

NOTES:

AR303578

SITECHARACTERIZATION

• Contamination primarily foundin the upper two ft of soil

• No evidence of significantleaching to groundwater

• pH range in soils is 5.3 to 9.2• Lead saturation capacity of soil

is high (6,600 to 20,500 ppm asestimated in USEPA FS)

NOTES:

AR303579

NOTES:

PRP RECOMMENDEDREMEDY

• Excavate floodplain soils aboveaction levels to a depth of 2 ftand relocate

• Flatten waste piles and relocateas needed

• Consolidate all on-site soils-withlead > action levels

• Backfill consolidationexcavations with clean soils

• Place a limestone blanket overconsolidated materials

AR303580

NOTES:

PRP RECOMMENDEDREMEDY

• Place a multi-layer cap overconsolidation area

• Demolish buildings within theconsolidation area

• Stormwater diversion controls• Creek sedimentremoval/remediation

• Wetlands creation• Deed and access restrictions,long-term monitoring

AR30358I

NOTES:

MERITS TO THE PRPAPPROACH

• Effectively prevents exposurepathway completion

• Provides a cost effectiveremedy for the site

• Provides for longrtermindustrial use of the site

• Limestone blanket provides, treatment• Cap significantly reduces

infiltration

RR303582

JACK'S CREEK/SITKIN SMELTINGREMEDIATION COST ESTIMATE

RESULTS

ALTERNATIVE-OPTION

1 -A (COVER)

1-B (MULTI-LAYER CAP)

2-A (CONSOLIDATEAND CAP WITHOUTUNDERLINER)

2-B (CONSOLIDATEAND CAP WITHUNDERLINER)

3 (TREAT AND CAP)

ESTIMATED PRESENTWORTH COST

$6.4 TO $7.0 MILLION

$10 TO $12 MILLION

$10 TO $11 MILLION

$14 TO $15 MILLION

$42 TO $43 MILLION

AR303583

MERITS TO THE PRPAPPROACH

• Provides protection to thefloodplain

• Provides for protection of creekresources

• Replaces wetlands affectedhistorical site activities

• Provides for long-termmonitoring

by

NOTES:

MERITS OF MODELINGAND LEACHING

STUDIES

• Provides scientific evidence tosupport final remedy selection

• Provides additional informationto support selection of lead .action levels

• More effectively indicates theleachability of lead under realworld conditions

NOTES:

AR303585

OBJECTIVES OFMODELING STUDIES

Predict mobility of lead inunsaturated site soilsQuantify benefit of cap basedon teachabilityHelp determine appropriate leadaction level

- For soil/wastes to becapped

- For soils to be covered

NOTES:

AR303586

——POSSIBLE——MATHEMATICAL

MODELS

HELP2 - infiltration of waterthrough a capVLEACH - vadose zonemigration based on equilibriumsolubilities in one dimension(adsorption included)SUMMERS - contaminantmigration within aquifer basedon complete mixing

NOTES:

flR303587

HELP2 MODEL

• Estimates the rate of waterinfiltration through soil

• Estimates leachate volumegenerated based on differentconditions (uncapped, differentcaps, covers)

• Widely used and accepted byUSEPA

NOTES:

A.R303588

INFILTRATIONASSESSMENT

HYDRAULIC EVALUATION OF LANDFILLPERFORMANCE MODEL

(HELP2)

MICIHTiTIOM

EVAPOTRANSPIHATIOM

INPILTIUTtOM

flR303589

INPUT TO HELP2

• WILTING POINT • MAXIMUM LATERAL• FIELD CAPACITY DRAINAGE DISTANCE• MtLUCAPAUTY ALONG SLOPE• SATURATED qniL Bin K nPN<?iTYHYDRAULIC * SOIL BULK DENSITYCONDUCTIVITY • AVERAGE DAILY

. EVAPORATION TEMPERATURECOEFFECIENT • QUANTITY OF WATERIMITIAI cn.i ' AVAILABLE FOR

• INITIAL SOIL TRANSPIRATIONWATER CONTENT TRANSPIRATION.....,_._.-.. • AVERAGE NUMBER OFTvnc DAYS WITH SNOW™PE- • COVER

• POROSITY ^ NUMBER OF .COVER• SITE SURFACE LAYERS ANDAREA THICKNESS

• SLOPE OF COVER , UPSTREAM RUNOFFSURFACE

AR303590

NOTES:

VLEACH MODEL

• Uses water infiltration rate fromHELP2

• Assumes partitioning betweenthree phases (liquid, vapor, andsorbed)

• Considers adsorption, but notdispersion or biodegradation oflead

• Estimates a conservative massimpact of lead to thegroundwater through time

AR303591

VADOSE ZONE MIGRATIONASSESSMENT-VLEACH

DOWNWARD ADWCT10M

AR303592

INPUT TO VLEACH

Q - GROUNOWATER RECHARGE RATE (ft/yr)p - DRY BULK DENSITY OF SOIL (g/CC)* - TOTAL EFFECTIVE POROSITY (DIMENSIONLESS)9 - VOLUMETRIC WATER CONTENT (DIMENSIONLESS)fee - FRACTIONAL ORGANIC CARBON CONTENTD - DEPTH FROM GROUND SURFACE TO WATER TABLE (ft)KOO - ORGANIC CARBON DISTRIBUTION COEFFECIENTKM - HENRY'S CONSTANTS - AQUEOUS SOLUBILITY 9 10' C (mg/1)Dwn- FREE AIR DIFFUSION COEFFICIENT {m»/day)

AR303593

NOTES:

SUMMERS MODEL

i Uses water infiltration rate fromHELP2

> Uses mass loading to groundwaterfromVLEACH

' Assumes soil-water partitioningand equilibrated/complete mixingin the aquiferEstimates lead concentration inthe aquiferEstimates a protective lead levelfor soil (by back calculation)

AFT30359I*

AQUIFER CONCENTRATIONASSESSMENT - SUMMERS

MASS LOAOIMO

AR303595

INPUT TO SUMMERS

Q - GROUNDWATER RECHARGE RATE (ft/yr)A, - SOURCE AREA (ft1)Cp • SOIL CONCENTRATION IN SOURCE AREA (mg/kg)foo - FRACTIONAL ORGANIC CARBON CONTENTKOO- ORGANIC CARBON DISTRIBUTION COEFFECIENT

(mg/kg/mg/l)K - AQUIFER HYDRAULIC CONDUCTIVITY (ft/yr)h - AQUIFER THICKNESS (rt)i • AQUIFER HYDRAULIC GRADIENT (DIMENSIONLESS)C. - AQUIFER BACKGROUND CONCENTRATION (mg/L)

UR303596

MODELING STUDIESOUTPUT

• HELP2 - Estimate of waterinfiltration rate

• VLEACH - Estimate of theimpact of lead-bearing soils onthe groundwater

• SUMMERS - Estimates of--Lead concentration ingroundwater

-Protective soil leadconcentration

NOTES:

fiR303597

END USE OFMODELING DATA

1 Results summarized andanalyzed in report to PADERand USEPAResults assessed to determinefeasibility of capping with andwithout solidificationResults used to determineappropriate action level(s) forlead in capped and uncappedareas

NOTES:

AR303598

OBJECTIVES OFLEACHABILIT Y. STUDIES

Predict teachability of lead fromsite soils under realistic site-specific conditionsHelp determine appropriate leadaction level(s)

NOTES:

AR303599

LEACHABILITYSTUDIES

• Test media (soil or waste) iscontacted by leaching fluid(s)

• Column - contact occurs inflow-through conditions

• Batch - contact occurs in static,saturated conditions ' .

• Estimates potential leaching oflead from site media

NOTES:

AR303600

TEST MEDIA

• Use various site soils and/orwaste pile materials

• Use various lead concentrations• Use clean sand as a blank• Analyze chemical and physicalproperties of test media beforeand after leachability studies

• Analyze leachate for total leadcontent

NOTES:

AK3036Q

BATCH TESTS

• Modified ANS 16.1 test• At each sample point, freshleaching fluid is used

• Seven leaching intervalsproposed (2 hours to 5 days)

• Results are easily reproducibleand comparable to previousresults

• Requires shorter test duration

NOTES:

ftR303602

NOTES:

COLUMN TESTS

• Simulates actual site leachingconditions

• Labor and equipment intensive• Requires longer test duration, (greater than 5 days) until stable leadconcentration in effluent is reached

• Maximum soil particle diameter =10 % of column diameter

• ASTM column setup methods; four ,columns

• Leaching rate of one pore volumeper 24 hours

AR303603

NOTES:

LEACHING FLUIDS

• Design to reflect likely siteconditions

• Actual precipitation and runofffrom site

• Synthetic precipitation leachingprocedure (SPLP) leachingfluid, pH = 4.2

• Deionized water

END USE OFLEACHING DATA

1 Results summarized andanalyzed in report to PADERand USEPAResults assessed to determinefeasibility of capping with andwithout solidificationResults used to determineappropriate action level(s) forlead (with and without capping,treatment)

NOTES:

AR303605

RCRA ISSUES

• Treatment of the waste piles• Treatment of characteristicwaste

• Lined vs. unlined containment.• Floodplain issues• ARARs issues/waivers• PA industrial reuse bill signed

NOTES:NOTES:

&R3Q36Q6