EPA/ROD/R05-89/109
1989
EPA Superfund
Record of Decision:
WAUSAU GROUND WATER CONTAMINATION
EPA ID: WID980993521
OU02
WAUSAU, WI
09/29/1989
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* CITY OF WAUSAU * WAUSAU ENERGY COMPANY
* MARATHON ELECTRIC COMPANY * AMOCO OIL CORPORATION
* WAUSAU CHEMICAL COMPANY
SEVERAL NEGOTIATION MEETINGS WERE HELD TO DISCUSS TECHNICAL AND LEGAL ISSUES OF A CONSENT DECREE FOR THE
SITE. HOWEVER, NEGOTIATIONS WERE UNSUCCESSFUL, AND THE PRPS DECLINED TO PARTICIPATE IN THE RI/FS. THE US EPA
THEN CONTRACTED WITH WARZYN ENGINEERING, INC. IN JULY 1987 TO CONDUCT THE RI/FS.
ALTHOUGH THE PRPS FAILED TO REACH AN AGREEMENT WITH US EPA, THEY HAVE MAINTAINED CONSIDERABLE INVOLVEMENT IN
US EPA'S STUDY. TWO OF THE FIVE PRPS CONDUCTED AN INVESTIGATION OF THE WEST WELL FIELD AND ALL HAVE
REQUESTED SPLIT SAMPLES AND/OR RESULTS OF DATA COLLECTED. IN ADDITION, TWO OF THE PRPS, THE CITY OF WAUSAU
AND MARATHON ELECTRIC, HAVE ENTERED INTO A CONSENT DECREE TO PERFORM THE OPERABLE UNIT REMEDIAL
DESIGN/REMEDIAL ACTION (RD/RA).
IN NOVEMBER, 1987, (AS AMENDED APRIL 1988) US EPA FILED SUIT FOR RECOVERY OF PAST COSTS SPENT ON US EPA'S
EMERGENCY RESPONSE ACTIONS. A SETTLEMENT WAS REACHED BETWEEN THREE OF THE FOUR DEFENDANT PRPS (MARATHON
ELECTRIC, THE CITY OF WAUSAU, AND WAUSAU CHEMICAL) FOR APPROXIMATELY 85% OF PAST COSTS. A CONSENT DECREE WAS
ENTERED IN FEDERAL DISTRICT COURT JULY 18, 1989. A SECOND CONSENT DECREE WITH WAUSAU ENERGY IS EXPECTED TO
BE LODGED WITH THE COURT IN THE NEAR FUTURE.
NEGOTIATIONS WITH THE PRPS FOR THE FINAL RD/RA HAVE BEEN POSTPONED AT THE REQUEST OF THE PRP GROUP. THIS IS
BASED ON THE FACT THAT TWO OF THE PRPS ARE CURRENTLY INVOLVED IN THE IMPLEMENTATION OF THE OPERABLE UNIT
RD/RA BASED ON AN AGREEMENT WITH US EPA TO PERFORM THE OPERABLE UNIT, AND TO ALLOW THE FINAL REMEDY PRP GROUP
TO ORGANIZE. SPECIAL NOTICE LETTERS WILL BE SENT FOLLOWING ROD SIGNATURE TO THE FIVE PRPS LISTED ABOVE.
NEGOTIATIONS WILL PROCEED ACCORDING TO US EPA'S GENERAL GUIDANCE AND POLICIES.
#CR
III. COMMUNITY RELATIONS
AN RI/FS "KICK-OFF" PUBLIC MEETING WAS HELD IN SEPTEMBER 1987, TO INFORM THE LOCAL RESIDENTS OF THE SUPERFUND
PROCESS AND THE WORK TO BE CONDUCTED. ISSUES RAISED DURING THE MEETING, ATTENDED MOSTLY BY PRP AGENTS AND
CITY OFFICIALS, INCLUDED THE COST OF THE RI/FS, THE ESTIMATED TIME TO COMPLETE THE STUDY, AND THE NUMBER OF
PREVIOUS STUDIES PERFORMED FOR THE SITE.
A SECOND PUBLIC MEETING WAS HELD IN OCTOBER 1988 TO DISCUSS THE FINDINGS OF THE PHASE I RI AND PFS, AND TO
PRESENT THE PROPOSED PLAN FOR AN OPERABLE UNIT AT THE SITE. TWO FORMAL PUBLIC COMMENTS WERE RECEIVED DURING
THE PUBLIC MEETING AND WRITTEN COMMENTS WERE ALSO RECEIVED DURING THE PUBLIC COMMENT PERIOD. ALL COMMENTS
RECEIVED DURING THE COMMENT PERIOD AND US EPA'S RESPONSES WERE INCLUDED IN THE RESPONSIVENESS SUMMARY FOR THE
INTERIM ROD.
INFORMATION REPOSITORIES HAVE BEEN ESTABLISHED AT WAUSAU CITY HALL, 407 GRANT STREET, AND THE MARATHON COUNTY
PUBLIC LIBRARY, 400 FIRST STREET, WAUSAU, WISCONSIN. IN ACCORDANCE WITH SECTION 113(K)(1) OF CERCLA, THE
ADMINISTRATIVE RECORD FOR THE SITE IS AVAILABLE TO THE PUBLIC AT THESE LOCATIONS. THE DRAFT FS AND THE
PROPOSED PLAN WERE AVAILABLE FOR PUBLIC REVIEW AND COMMENT FROM AUGUST 14, 1989 TO SEPTEMBER 12, 1989.
A PUBLIC MEETING TO DISCUSS THE FINDINGS OF THE RI/FS AND TO PRESENT US EPA'S PREFERRED ALTERNATIVE FOR THE
FINAL REMEDY WAS HELD AUGUST 22, 1989 IN THE WAUSAU CITY HALL. FOUR FORMAL PUBLIC COMMENTS WERE RECEIVED
DURING THE PUBLIC MEETING. ALL OF THE COMMENTS WERE IN SUPPORT OF US EPA'S PREFERRED ALTERNATIVE. ONE
ADDITIONAL COMMENT WAS RECEIVED DURING THE REMAINDER OF THE PUBLIC COMMENT PERIOD. ALL COMMENTS WILL BE
ADDRESSED IN THE RESPONSIVENESS SUMMARY OF THIS DOCUMENT. THE PROVISIONS OF SECTIONS 113(K)(2)(I-V) AND 117
OF CERCLA RELATING TO COMMUNITY RELATIONS HAVE BEEN SATISFIED.
#SRR
IV. SCOPE AND ROLE OF RESPONSE ACTION
THE SCOPE OF THIS RESPONSE ACTION IS TO ADDRESS THE REMAINING CONCERNS (PRINCIPAL THREATS) AT THE SITE. AS
DISCUSSED, A PREVIOUS OPERABLE UNIT ACTION AT THE SITE ADDRESSES THE CONTAMINANT PLUME ORIGINATING FROM THE
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FORMER LANDFILL/MARATHON ELECTRIC SOURCE AREA WHICH AFFECTS CW6.
DURING DEVELOPMENT OF THE FINAL FS, IT WAS DETERMINED THAT THE DEEP PLUME WHICH ORIGINATES FROM THE FORMER
CITY LANDFILL AREA AND MIGRATES UNDER THE RIVER TO CW3 WOULD BEST BE ADDRESSED BY PURGING GROUNDWATER AT
THE SAME LOCATION AS THE INTERIM REMEDY EXTRACTION SYSTEM. THEREFORE, IT WAS DETERMINED THAT AN INCREASE IN
THE MINIMUM PUMPING RATES CALLED FOR IN THE EXTRACTION SYSTEM AND MODIFICATIONS TO THE MONITORING PLAN
WOULD PROVIDE THE MOST EFFECTIVE REMEDIATION FOR THIS CONTAMINANT PLUME. IT WAS ALSO ASSUMED THAT THE CITY
WOULD CONTINUE TO USE CW3 AS A SUPPLY WELL AND THUS CONTINUE TO REMOVE CONTAMINANTS FROM THE MOST EASTERN
PORTION OF THE PLUME.
THE SELECTED ALTERNATIVE FOR THE FINAL PHASE OF THE WAUSAU PROJECT, IN CONJUNCTION WITH THE OPERABLE UNIT,
WILL ADDRESS ALL CONCERNS AT THE SITE. REMAINING CONCERNS INCLUDE THREE SOURCE AREAS AND THE SHALLOW EAST
SIDE GROUNDWATER CONTAMINANT PLUME ORIGINATING FROM THE WAUSAU CHEMICAL SOURCE AREA. THE IDENTIFIED SOURCE
AREAS INCLUDE; FORMER CITY LANDFILL/MARATHON ELECTRIC PROPERTY, WAUSAU CHEMICAL PROPERTY, AND WAUSAU ENERGY
PROPERTY.
THE FINAL REMEDY FOR THE SITE IS INTENDED TO ADDRESS THE ENTIRE SITE WITH REGARDS TO THE PRINCIPAL THREATS TO
HUMAN HEALTH AND THE ENVIRONMENT POSED BY THE SITE AS INDICATED IN THE RISK ASSESSMENT FOR THE SITE. THE
FINDINGS OF THE RISK ASSESSMENT ARE INCLUDED IN THE RI REPORT AND ARE SUMMARIZED IN A LATER SECTION OF THIS
DOCUMENT.
#css
V. CURRENT SITE STATUS AND SITE CHARACTERISTICS
A. CURRENT SITE STATUS
THE RI/FS WAS COMPLETED IN AUGUST 1989 FOR US EPA BY ITS CONTRACTOR, WARZYN ENGINEERING, INC. THE RI
ENTAILED TWO PHASES OF FIELD SAMPLING EVENTS. PHASE I OF THE RI FIELD WORK WAS CONDUCTED FROM AUGUST THROUGH
JANUARY 1987, RESULTS OF WHICH ARE SUMMARIZED IN THE APRIL 1988 TECHNICAL MEMORANDUM. PHASE II OF THE RI
FIELD WORK WAS CONDUCTED FROM JUNE TO SEPTEMBER 1988. RESULTS OF BOTH PHASES OF WORK ARE INCLUDED IN THE RI
REPORT FOR THE SITE.
THE FS DETAILS THE DEVELOPMENT AND EVALUATION OF AN ARRAY OF REMEDIAL ACTION ALTERNATIVES TO ADDRESS THE
ENTIRE WAUSAU GROUNDWATER CONTAMINATION SITE AND SOURCES IMPACTING IT.
B. SITE CHARACTERISTICS
1. HYDROGEOLOGY
THE CITY PRODUCTION WELLS ARE LOCATED WITHIN GLACIAL OUTWASH AND ALLUVIAL SEDIMENTS UNDERLYING AND ADJACENT
TO THE WISCONSIN RIVER. THE AQUIFER IS LOCATED WITHIN A BEDROCK VALLEY WHICH IS UNDERLAIN AND LATERALLY
BOUNDED BY RELATIVELY IMPERMEABLE IGNEOUS BEDROCK. GROUNDWATER FLOW WITHIN THE UNCONFINED GLACIAL AQUIFER HAS
BEEN DRASTICALLY CHANGED BY THE INSTALLATION OF THE PRODUCTION WELLS. UNDER NON-PUMPING CONDITIONS,
GROUNDWATER FLOWS TOWARD THE WISCONSIN RIVER AND ITS TRIBUTARY (BOS CREEK). GROUNDWATER NATURALLY DISCHARGES
AT THE SURFACE WATER BODIES.
HOWEVER, UNDER PUMPAGE CONDITIONS, GROUNDWATER FLOWS TOWARD THE PRODUCTION WELLS. THE NATURAL GROUNDWATER
FLOW DIRECTIONS ARE FREQUENTLY REVERSED DUE TO CITY WELL PUMPING WHICH INDUCES RECHARGE OF SURFACE WATER INTO
THE AQUIFER. THE HORIZONTAL FLOW IN THE VICINITY OF THE WELL FIELD IS INDICATED BY THE POTENTIOMETRIC
CONTOURS SHOWN IN FIGURE 4.
THE POTENTIOMETRIC SURFACE MAP ALSO INDICATES THAT THE CONE OF DEPRESSION FROM THE EAST WELL FIELD APPEARS TO
AFFECT GROUNDWATER FLOW BELOW AND TO THE WEST OF THE WISCONSIN RIVER. MONITORING WELL NESTS LOCATED AT
MARATHON ELECTRIC INDICATE VERY SLIGHT DOWNWARD GRADIENTS ADJACENT TO THE WISCONSIN RIVER. BELOW THE
WISCONSIN RIVER, THE EAST WELL FIELD PRODUCTION WELL PUMPAGE HAS INDUCED SURFACE WATER RECHARGE OF THE
AQUIFER, CAUSING FLOW DOWNWARD THROUGH THE RIVER BED AND TOWARD CW3.
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AQUIFER HYDRAULIC CONDUCTIVITY TESTS PERFORMED DURING THE PHASE I RI INVESTIGATION INDICATED HYDRAULIC
CONDUCTIVITY VALUES RANGING FROM 1.7 X (10-4) CM/SEC TO 8.1 X (10-2) CM/SEC. THE OVERALL AVERAGE HYDRAULIC
CONDUCTIVITY OF THE OUTWASH AQUIFER IS APPROXIMATELY 2.2 X (10-2) CM/SEC, BASED ON TEST DATA AT MONITORING
WELLS.
2. CHEMICAL CHARACTERISTICS
A. GROUNDWATER QUALITY
GROUNDWATER QUALITY SAMPLING CONDUCTED DURING BOTH PHASES OF THE FIELD INVESTIGATION HAS IDENTIFIED A
VERTICAL AND LATERAL DISTRIBUTION OF TOTAL CHLORINATED ETHENES WHICH SUGGESTS THAT A MINIMUM OF THREE SOURCES
ARE AFFECTING THE CITY WELL FIELD. THE ESTIMATED AREAL DISTRIBUTION OF TOTAL CHLORINATED ETHENES IS SHOWN IN
FIGURE 5. THE DISTRIBUTION IS BASED ON A COMBINATION OF DATA OBTAINED FROM LABORATORY VOC ANALYSES OF ROUNDS
1, 2, AND 3 GROUNDWATER SAMPLES (OCTOBER 1987 TO SEPTEMBER 1988), AND FIELD LABORATORY ANALYSES OF
GROUNDWATER SAMPLES COLLECTED DURING DRILLING (OCTOBER AND NOVEMBER 1987).
WEST SIDE MONITORING WELLS DELINEATE A DEEP (GREATER THAN 100 FOOT) NORTH-SOUTH TRENDING TCE PLUME. BASED ON
THE VERTICAL DISTRIBUTION OF TCE THROUGHOUT THE AQUIFER IN THE VICINITY OF THE OLD CITY LANDFILL AND THE
PRESENCE OF TCE IN THE UNSATURATED ZONE IN THIS AREA, A SOURCE APPEARS TO BE LOCATED WITHIN THE NORTHERN
PORTION OF THE FORMER CITY LANDFILL/MARATHON ELECTRIC PROPERTY. THE PLUME APPEARS TO HAVE MIGRATED
NORTHWARD, UNDER INFLUENCE OF PUMPAGE FROM CW6. THE HIGHEST TCE CONCENTRATION (4200 UG/L) IN THE PLUME WAS
DETECTED APPROXIMATELY 550 FEET SOUTH OF CW6.
TCE WAS ALSO OBSERVED IN THE SHALLOW AQUIFER BETWEEN BOS CREEK AND CW6. THIS PLUME IS SHOWN ON FIGURE 5 BY
THE LIGHTLY SHADED CONTOURS BETWEEN BOS CREEK AND CW6. THE SHALLOW AQUIFER TCE CONTAMINATION APPEARS TO
RESULT FROM THE INDUCED INFILTRATION OF SURFACE WATER FROM BOS CREEK, WHICH HAS BEEN CONTAMINATED BY THE
DISCHARGE FROM CW6. THE INDUCED SURFACE WATER RECHARGE OF THE AQUIFER IS EVIDENT FROM THE DOWNWARD VERTICAL
GRADIENTS AT MONITORING WELL NESTS IN THAT AREA. BASED ON LABORATORY ANALYSES OF SAMPLES COLLECTED DURING
THE RI FIELD WORK, TCE CONCENTRATIONS ADJACENT TO THE CW6 DISCHARGE WERE ABOVE 100 UG/L. TCE CONCENTRATIONS
IN THE PONDED AREA DOWNSTREAM WERE APPROXIMATELY 70 UG/L. TCE WAS NOT DETECTED IN SURFACE WATER SAMPLES
COLLECTED UPSTREAM OF THE CW6 DISCHARGE, NOR WAS IT DETECTED AT THE POINT OF DISCHARGE OF BOS CREEK TO THE
WISCONSIN RIVER.
THE DISTRIBUTION OF TCE IN MONITORING WELLS LOCATED BETWEEN THE WISCONSIN RIVER AND CW3 SUGGEST EASTWARD
MIGRATION OF A DEEP TCE PLUME BELOW THE WISCONSIN RIVER ALSO FROM THE VICINITY OF THE FORMER CITY LANDFILL
(REFER TO FIGURE 5). TCE APPEARS TO BE VERTICALLY DISTRIBUTED THROUGHOUT THE AQUIFER IN THE VICINITY OF THE
OLD CITY LANDFILL. SLIGHT VERTICAL DOWNWARD GRADIENTS WERE OBSERVED IN MONITORING WELLS IN THE AREA. THE
HIGHEST CONCENTRATIONS OF TCE WERE DETECTED AT A DEPTH OF APPROXIMATELY 115 FEET. AFTER MOVING INTO THE
DEEPER PORTION OF THE AQUIFER, A PORTION OF THE PLUME APPEARS TO MIGRATE EASTWARD UNDER THE INFLUENCE OF
PUMPAGE FROM CW3 (REFER TO FIGURE 4).
EAST SIDE MONITORING WELLS INDICATE THREE PLUMES WITHIN THE EAST WELL FIELD AREA, ONE FROM THE WEST SIDE
ORIGINATING FROM THE FORMER CITY LANDFILL/MARATHON ELECTRIC PROPERTY (DISCUSSED ABOVE) AND TWO ORIGINATING
SOUTHWEST OF CW3. THESE TWO PLUMES ARE RESTRICTED TO THE SHALLOW PORTION OF THE AQUIFER (UPPER 40 FEET), AND
CONSIST OF PRIMARILY PCE, TCE, AND DCE. BOTH OF THESE PLUMES HAVE RESULTED FROM RELEASES OF PCE FROM THE
WAUSAU CHEMICAL FACILITY.
A LARGE WIDELY DISPERSED VOC PLUME EXTENDING EASTWARD FROM THE WAUSAU CHEMICAL PROPERTY WAS IDENTIFIED DURING
THE THREE SAMPLING ROUNDS. THE HIGHEST CONCENTRATIONS OF VOCS IN THIS PLUME WERE DETECTED IN THE VICINITY
OF THE WAUSAU CHEMICAL STORAGE AREA BEHIND THE SOUTHERN PART OF THE BUILDING.
A SECOND PLUME WAS DETECTED NORTH OF THE WAUSAU CHEMICAL FACILITY IN THE VICINITY OF THE NORTHERN LOADING
DOCK. THIS PLUME WAS DIFFERENTIATED FROM THE OTHER PLUME BY THE RELATIVE ABSENCE OF PCE DEGRADATION PRODUCTS
(TCE, 1,2-DCE, ETC.). ANALYSES CONDUCTED FOR ROUND 3 SAMPLES (MAY 1988) INDICATE A PCE CONCENTRATION OF
APPROXIMATELY 2000 UG/L. BASED ON THE DIFFERENCES IN PLUME COMPOSITION AND AREAL DISTRIBUTION, THE TWO
SHALLOW AQUIFER IMPACTS APPEAR TO BE THE RESULT OF SEPARATE RELEASE EVENTS FROM ONE OR MORE SOURCES AT THE
WAUSAU CHEMICAL FACILITY.
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COMPARISON OF VOC CONCENTRATIONS AND PUMPAGE RATES AT CW3 AND CW4 SUGGESTS THAT BOTH WELLS HAVE EXPERIENCED
MULTIPLE IMPACTS FROM THE SAME SOURCE AREA; THE EXTENT OF IMPACT BEING DEPENDANT ON PUMPING SCHEMES OF THE
CITY'S SUPPLY WELLS, RIVER STAGE, AND THE STRENGTH OF THE SOURCE. TOTAL VOCS AT BOTH CW3 AND CW4 HAVE BEEN
DECREASING OVER TIME INDICATING A POSSIBLE REDUCTION IN SOURCE INTENSITY. HOWEVER, TCE CONCENTRATIONS AT CW3
HAVE REMAINED RELATIVELY CONSISTENT WHICH IS ATTRIBUTED TO THE TCE PLUME MIGRATING UNDER THE RIVER FROM THE
WEST SIDE.
B. SOURCES OF CONTAMINATION
CONTAMINATION SOURCE AREAS WERE IDENTIFIED AND CHARACTERIZED BASED ON RESULTS OF FIELD SAMPLING OF SOILS,
LANDFILL CONTENTS (USING TEST PITS AND SOIL BORINGS), GROUNDWATER, SURFACE WATER, SEDIMENT AND SOIL GAS
MEDIA. BASED ON SAMPLING ACTIVITIES CONDUCTED DURING THE RI, FOUR SOURCE AREAS OF VOCS WERE IDENTIFIED. TWO
OF THESE SOURCES ARE LOCATED ON THE WEST SIDE OF THE WISCONSIN RIVER (THE FORMER CITY LANDFILL AND BOS
CREEK) AND TWO SOURCES ARE LOCATED ON THE EAST SIDE (WAUSAU CHEMICAL AND WAUSAU ENERGY).
THE FORMER CITY LANDFILL/MARATHON ELECTRIC PROPERTY OCCUPIES A FORMER SAND AND GRAVEL PIT LOCATED ON THE WEST
BANK OF THE WISCONSIN RIVER. THE LANDFILL, WHICH CONSISTS OF APPROXIMATELY 4.5 ACRES, OPERATED BETWEEN 1948
AND 1955 AND ACCEPTED ALMOST ALL COMMERCIAL, INDUSTRIAL, AND RESIDENTIAL WASTE GENERATED WITHIN THE CITY OF
WAUSAU. THE MAJORITY OF THE LANDFILL IS CURRENTLY COVERED BY A BITUMINOUS PAVEMENT PARKING LOT, HOWEVER THE
SOUTHERN PORTION IS VEGETATED.
THE PREDOMINANT SOURCE OF TCE CONTAMINATION TO CW6 AND CW3 APPEARS TO BE THE FORMER CITY LANDFILL/MARATHON
ELECTRIC PROPERTY. ELEVATED CONCENTRATIONS OF TCE WERE DETECTED IN GROUNDWATER, SOIL, AND SOIL GAS SAMPLES
OBTAINED FROM THE NORTHERN PORTION OF THE LANDFILL. SOIL GAS CONCENTRATIONS WITHIN THE LANDFILL RANGE FROM
BELOW MINIMUM DETECTION LIMITS (1.0 UG/L) TO APPROXIMATELY 107 UG/L. SOIL SAMPLES OBTAINED FROM BORINGS IN
THE VICINITY OF THE LANDFILL CONTAIN CONCENTRATIONS OF APPROXIMATELY 200 UG/KG. GROUNDWATER SAMPLES OBTAINED
FROM THE WATER TABLE IN THE VICINITY OF THE LANDFILL INDICATE TCE CONCENTRATIONS RANGING FROM 16 UG/L TO
APPROXIMATELY 1900 UG/L. ALSO DETECTED IN THE VICINITY OF THE LANDFILL WERE 1,1,1-TRICHLOROETHANE (TCA) ,
1,2-DICHLOROETHENE, CHLOROFORM, AND CARBON TETRACHLORIDE AT CONCENTRATIONS GENERALLY BELOW 100 UG/L.
IN ADDITION TO VOCS, CONTAMINANTS IDENTIFIED IN LANDFILL SOIL/WASTE SAMPLES INCLUDE POLYCYCLIC AROMATIC
HYDROCARBONS (PAHS) AND METALS. PAHS WERE FOUND THROUGHOUT THE FILL, WITH THE HIGHEST CONCENTRATIONS OBSERVED
IN THE CENTER OF THE FILL AREA. HEAVY METALS WERE DISTRIBUTED THROUGHOUT THE FILL. CHROMIUM, ZINC, AND
NICKEL WERE ALSO DETECTED IN GROUNDWATER SAMPLES FROM BENEATH THE FILL. THESE METALS APPEAR TO BE RESTRICTED
TO THE IMMEDIATE VICINITY OF THE LANDFILL AND HAVE NOT BEEN DETECTED IN GROUNDWATER SAMPLES OUTSIDE OF THE
FILL AREA.
BASED ON CALCULATIONS PERFORMED FOR THE RI, THE TOTAL AMOUNT OF VOCS REMAINING IN THE UNSATURATED SOILS IN
THE NORTHERN PORTION OF THE LANDFILL IS ESTIMATED TO BE APPROXIMATELY 300 POUNDS. THIS IS CONSIDERED AN
ESTIMATE AND COULD VARY CONSIDERABLY IF CONTAMINATION EXISTS BENEATH THE FILL AND/OR IF AREAS OF UNDETECTED
HIGH CONCENTRATIONS OR NON-AQUEOUS PHASE OF CONTAMINANTS EXIST.
AS DISCUSSED PREVIOUSLY, LOW LEVELS OF TCE WERE ALSO DETECTED IN SAMPLES FROM SHALLOW MONITORING WELLS ON THE
WEST SIDE IN THE VICINITY OF BOS CREEK (SEE FIGURE 5). THE SHALLOW CONTAMINATION APPEARS TO BE A RESULT OF
INFILTRATION OF TCE CONTAMINATED WATER TO THE AQUIFER FROM CW6 DISCHARGING TO THE CREEK.
THE WAUSAU CHEMICAL COMPANY IS LOCATED BETWEEN CW3 AND CW4 ON THE EAST BANK OF THE WISCONSIN RIVER. THE
FACILITY, ESTABLISHED IN 1964, IS A BULK SOLVENT DISTRIBUTOR AND A TRANSFER STATION FOR SHIPMENT OF WASTE
CHEMICALS AND SOLVENTS FROM AREA BUSINESSES. THE FACILITY EXPERIENCED TWO DOCUMENTED PCE SPILLS IN 1983
TOTALING MORE THAN 1000 GALLONS, AND HAS BEEN CITED FOR GENERAL POOR 'HOUSEKEEPING' PRACTICES. AS EARLY AS
1975, WORKERS AT THE ADJACENT WATER FILTRATION PLANT REPORTED "NOXIOUS ODORS" IN EXCAVATED SOILS DURING
EXPANSION OF THE PLANT.
SOLVENTS RELEASED FROM THE WAUSAU CHEMICAL SOURCE AREAS ARE RESPONSIBLE FOR A LARGE PERCENTAGE OF THE SHALLOW
GROUNDWATER CONTAMINATION IN THE EAST WELL FIELD. SOIL GAS AND SOIL BORING DATA REFLECTING THE
DISTRIBUTION OF VOCS IN UNSATURATED SOILS WERE COLLECTED AS PART OF THE SOIL GAS SURVEY AND DURING SOIL
BORING FOR SOURCE CHARACTERIZATION. RESULTS OF THIS DATA INDICATE HIGHER CONCENTRATIONS OF CONTAMINANTS ARE
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LOCATED IN THE SOUTHERN PORTION OF THE SITE WITH DECREASING CONCENTRATIONS WITHIN AN ELONGATED CONTAMINANT
ZONE TRENDING TOWARD THE EAST-NORTHEAST. HOWEVER, ELEVATED CONCENTRATIONS OF PCE WERE ALSO FOUND IN
UNSATURATED SOILS NEAR THE NORTH LOADING DOCK. THE HIGHEST LEVELS OF PCE IN SOIL GAS WAS REPORTED FROM THE
SOUTHERN END OF THE FACILITY AT A CONCENTRATION OF 4080 UG/L. ANALYSES OF SOIL SAMPLES INDICATE 3500 UG/KG
OF PCE IN THE VICINITY OF THE NORTH LOADING DOCK, AND 1000 UG/KG AT THE SOUTH END OF THE PROPERTY.
BASED ON CALCULATIONS PERFORMED FOR THE RI, THE TOTAL AMOUNT OF VOCS REMAINING IN THE SOILS AT WAUSAU
CHEMICAL IS APPROXIMATELY 300 POUNDS. THIS IS CONSIDERED AN ESTIMATE AND COULD VARY CONSIDERABLY IF
CONTAMINATION EXISTS BENEATH EITHER THE FILTRATION PLANT OR THE WAUSAU CHEMICAL BUILDING.
THE WAUSAU ENERGY PROPERTY LOCATED DIRECTLY SOUTH OF CW3 WAS ALSO IDENTIFIED AS A SOURCE FOR GROUNDWATER
CONTAMINATION. THE FACILITY OPERATED AS A PETROLEUM BULK STORAGE AND DISTRIBUTION CENTER FROM THE LATE
1940'S UNTIL 1983. PREVIOUS PROPERTY OWNERS INCLUDE AMOCO OIL AND RUSH DISTRIBUTING. HISTORICAL DATA
INDICATE THAT AT LEAST SEVEN ABOVE GROUND STORAGE TANKS WERE LOCATED ON THE SOUTHERN HALF OF THE PROPERTY
AND CONTAINED VARIOUS PETROLEUM PRODUCTS.
SOIL GAS AND UNSATURATED SOIL SAMPLES HAVE BEEN CONDUCTED AT THE PROPERTY. RESULTS INDICATE VARIOUS
PETROLEUM BY-PRODUCTS, COMMONLY REFERRED TO AS BETX (BENZENE, ETHYLBENZENE, TOLUENE, AND XYLENES) IN
UNSATURATED SOILS AND GROUNDWATER BENEATH THE SITE. PCE WAS DETECTED AT LOW LEVELS IN ISOLATED SOIL SAMPLES
AND SOIL GAS SAMPLES AT DEPTH. THE MAXIMUM BETX CONCENTRATION REPORTED IN ON SITE SOILS WAS 25,100 UG/KG.
THE MAXIMUM CONCENTRATION OF PCE FOUND IN SOILS WAS 8,600 UG/KG (FROM A PREVIOUS STUDY-FOTH & VAN DYKE) AND
17.4 UG/KG FOUND IN SOIL GAS SAMPLES FROM THE PROPERTY.
#SSR
VI. SUMMARY OF SITE RISKS
CERCLA REQUIRES THAT US EPA PROTECT HUMAN HEALTH AND THE ENVIRONMENT FROM CURRENT AND POTENTIAL EXPOSURE TO
HAZARDOUS SUBSTANCES FOUND AT THE SITE. AN ENDANGERMENT ASSESSMENT WAS CONDUCTED AS PART OF THE RI IN
ORDER TO ASSESS THE CURRENT AND POTENTIAL RISKS FROM THE SITE. THIS SECTION SUMMARIZES THE AGENCY'S FINDINGS
CONCERNING THE RISKS FROM EXPOSURE TO GROUNDWATER AND AIR EMISSIONS AT THIS SITE.
ASSESSMENT OF SITE RELATED RISKS INVOLVED THE IDENTIFICATION OF CONTAMINANTS OF MOST CONCERN, ROUTES OF
CONTAMINANT MIGRATION AND POPULATIONS POTENTIALLY EXPOSED TO THE CONTAMINANTS. THIS INFORMATION WAS THEN
USED TO ESTIMATE EXPOSURE FROM CONTAMINANTS FOR THE POPULATION, WHICH WAS THEN COMPARED TO CHEMICAL TOXICITY
TO ARRIVE AT AN ESTIMATE OF HEALTH RISKS FOR THE SITE.
A. IDENTIFICATION OF CONTAMINANTS OF CONCERN
MORE THAN 50 COMPOUNDS WERE IDENTIFIED FROM THE RI DATA AS BEING PRESENT AT THE SITE (TABLE 2). A SUBSET OF
THE TOTAL NUMBER IDENTIFIED WAS SELECTED BASED ON WHICH COMPOUNDS POSE THE GREATEST HEALTH RISKS, THE
CONCENTRATIONS AND FREQUENCY OF DETECTION, AND THE PHYSICAL PROPERTIES RELATING TO MOBILITY AND PERSISTENCE.
BASED ON THE ABOVE CRITERIA, THE FOLLOWING INDICATOR CHEMICALS WERE CONSIDERED TO BE REPRESENTATIVE OF SITE
CONTAMINATION AND TO POSE THE GREATEST POTENTIAL HEALTH RISK.
* TETRACHLOROETHENE (PCE)
* TRICHLOROETHENE (TCE)
* 1,2-DICHLOROETHENE (DCE)
THESE COMPOUNDS HAVE BEEN USED TO EVALUATE TOXICITY, EXPOSURE PATHWAYS, AND POTENTIAL HEALTH RISKS FOR THE
SITE.
B. EXPOSURE ASSESSMENT
GROUNDWATER IN THE AREA IS THE CURRENT SOURCE OF DRINKING WATER FOR THE CITY OF WAUSAU WHICH PROVIDES POTABLE
WATER TO APPROXIMATELY 33,000 PEOPLE. THE AQUIFER OF CONCERN IS A CLASS I AQUIFER (SOLE-SOURCE AQUIFER
WITHOUT A VIABLE ALTERNATE SOURCE OF SUPPLY) AND IS HIGHLY VULNERABLE TO CONTAMINATION. THE CITY OF WAUSAU
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TREATS WATER PRIOR TO DISTRIBUTION THROUGH THE USE OF TWO AIR STRIPPERS. THE AIR STRIPPERS EFFECTIVELY
REDUCE VOC CONCENTRATIONS TO BELOW THE DETECTABLE LEVELS. HISTORICAL DATA INDICATE THAT DURING THE PERIOD OF
1982 THROUGH MID-1984, LEVELS OF VOCS IN THE CITY SUPPLY RANGED FROM 10 UG/L TO 100 UG/L. HOWEVER, IT IS NOT
KNOWN HOW LONG, PRIOR TO 1982, THE CITY'S WATER SUPPLY CONTAINED ELEVATED LEVELS OF VOCS. THEREFORE, THE
EXPOSURE SCENARIO FOR DRINKING WATER DID NOT ADDRESS POSSIBLE EXPOSURES PRIOR TO 1982.
CURRENTLY THERE ARE NO KNOWN PRIVATE WELLS USED FOR DRINKING WATER WITHIN THE STUDY AREA. IN ADDITION, THERE
IS A CITY OF WAUSAU ORDINANCE REQUIRING RESIDENTS TO UTILIZE THE MUNICIPAL SUPPLY FOR DOMESTIC PURPOSES.
HOWEVER, IN DEVELOPING HYPOTHETICAL EXPOSURE SCENARIOS FOR GROUNDWATER, INSTITUTIONAL CONTROLS WERE NOT
CONSIDERED ADEQUATE FOR PROTECTION FROM POTENTIAL FUTURE USE OF PRIVATE WELLS.
STRIPPING TOWER TREATMENT OF CONTAMINATED GROUNDWATER IS CURRENTLY OCCURRING AT THE CITY WATER TREATMENT
PLANT AND AT WAUSAU CHEMICAL. IN ADDITION, THE EFFLUENT FROM THE EXTRACTION WELL PROPOSED FOR THE INTERIM
REMEDY WILL ALSO INVOLVE DISPERSION OF VOC EMISSIONS TO THE AIR. INDICATOR CONTAMINANTS DISPERSED INTO THE
AIR FROM GROUNDWATER TREATMENT POSE A POTENTIAL EXPOSURE PATHWAY TO EMPLOYEES OF COMPANIES AND RESIDENTS NEAR
THE SOURCES OF AIR EMISSIONS.
THE POTENTIAL EXPOSURE PATHWAYS FOR THE SITE ARE LISTED BELOW AND SUMMARIZED IN TABLE 3. POTENTIAL HEALTH
RISKS WERE EVALUATED FOR THE FOLLOWING EXPOSURE PATHWAYS AND POTENTIALLY EXPOSED POPULATION.
* RESIDENTS USING MUNICIPAL WATER ASSUMING THEY ARE EXPOSED TO
CONTAMINANT CONCENTRATIONS EQUAL TO THE LABORATORY DETECTION
LIMITS OF 0.5 UG/L FOR PCE AND TCE, AND 1.0 UG/L FOR DCE.
* HYPOTHETICAL USERS OF PRIVATE WELL WATER ASSUMING A PRIVATE
WELL IS INSTALLED WITHIN THE CONTAMINATED AQUIFER IN THE
FUTURE. IT WAS ASSUMED THAT A USER WOULD BE EXPOSED TO THE
HIGHEST CONCENTRATIONS FOUND IN GROUNDWATER, APPROXIMATELY
4300 UG/L, TO OBTAIN THE WORST CASE SCENARIO FOR THIS EXPOSURE PATHWAY.
* RESIDENTS AND COMPANY EMPLOYEES EXPOSED VIA AIR EMISSIONS IN
THE VICINITY OF THE EMISSION SOURCES. ESTIMATED CONTAMINANT
EMISSIONS FROM THE SOURCE AREAS WERE CALCULATED ASSUMING
CONTINUOUS OPERATION OF THE AIR STRIPPERS AND A CONSTANT RATE
OF LOADING OF VOCS.
THE CONTAMINANT INTAKE, AND THUS RISK THAT AN INDIVIDUAL WOULD LIKELY INCUR FROM EXPOSURE TO AN INDICATOR
CHEMICAL WAS ESTIMATED FOR THE EXPOSURE PATHWAY OF CONCERN BY INCORPORATING STANDARD EXPOSURE ASSUMPTIONS OF
70-KG MAN, INGESTION OF TWO LITERS OF WATER PER DAY, INHALATION RATE OF 1.3 M3/HR AND A SKIN SURFACE AREA OF
18,200 CM2 FOR WATER, AND AN INHALATION RATE OF 20 M3/DAY FOR AIR EMISSIONS.
C. TOXICITY ASSESSMENT
BASED ON TOXICOLOGICAL STUDIES PERFORMED ON LABORATORY ANIMALS, BOTH PCE AND TCE ARE CLASSIFIED AS PROBABLE
HUMAN CARCINOGENS. SCIENTIFIC DATA COLLECTED TO DATE ARE NOT SUFFICIENT TO CLASSIFY DCE AS TO ITS
CARCINOGENIC POTENTIAL. THEREFORE, NO CANCER POTENCY FACTOR COULD BE DERIVED FOR DCE AND THUS, DCE WAS NOT
INCLUDED IN THE CALCULATION OF SITE RISKS. PCE IS ALSO ASSIGNED A REFERENCE DOSE VALUE. THIS VALUE
REPRESENTS THE LEVELS TO WHICH HUMANS CAN BE EXPOSED ON A DAILY BASIS WITHOUT ADVERSE EFFECTS. THE CRITICAL
TOXICITY VALUES (I.E., CANCER POTENCY FACTOR AND REFERENCE DOSE) FOR PCE AND TCE ARE LISTED IN TABLE 4.
THE Us EPA CONSIDERS INDIVIDUAL EXCESS CANCER RISKS IN A RANGE OF (10-4) TO (10-7) AS PROTECTIVE; HOWEVER,
THE (10-6) RISK LEVEL IS USED AS A POINT OF DEPARTURE FOR SETTING CLEANUP LEVELS AT SUPERFUND SITES. A (10-6)
IS CONSIDERED APPROPRIATE AS A POINT OF DEPARTURE FOR SETTING CLEANUP LEVELS AT THIS SITE CONSIDERING THAT
GROUNDWATER IS CURRENTLY USED FOR DRINKING WATER AND IS THE SOLE-SOURCE OF DRINKING WATER FOR THE RESIDENTS
OF WAUSAU.
D. SUMMARY OF RISK CHARACTERIZATION
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UNDER CURRENT WATER USE CONDITIONS, A POTENTIAL CARCINOGENIC RISK OF APPROXIMATELY ONE IN ONE MILLION 1 X
(10-6) WAS CALCULATED FOR USERS OF MUNICIPAL WATER FOR THE COMBINED EFFECTS OF PCE AND TCE. THESE RISK
LEVELS ARE BASED ON UNDETECTABLE LEVELS OF VOCS PRESENT IN THE TREATED WATER WITHIN THE CITY WATER
DISTRIBUTION SYSTEM. THE SHORT-TERM CARCINOGENIC RISKS TO HEALTH ASSOCIATED WITH PCE AND TCE CONTAMINATION
WOULD APPEAR TO BE MINIMAL UNDER CURRENT WATER USAGE PRACTICES. THE LONG-TERM CANCER RISK ASSOCIATED WITH
CITY WATER USE WAS CALCULATED TO BE 1.5 X (10-6) BASED ON A LIFE TIME OF 70 YEARS (SEE TABLE 5).
THE Us EPA HAS SET A MAXIMUM CONTAMINANT LEVEL (MCL) OF 5 UG/L TCE FOR DRINKING WATER. AN MCL OF 5 UG/L FOR
PCE IS UNDER CONSIDERATION FOR PROPOSAL IN THE NEAR FUTURE. MCLS ARE ENFORCEABLE STANDARDS PROMULGATED UNDER
THE SAFE DRINKING WATER ACT. BECAUSE PCE AND TCE ARE CARCINOGENIC AND ARE NOT CONSIDERED TO BE WITHOUT
HAZARD BELOW A GIVEN THRESHOLD, THE US EPA HAS SET A NON-ENFORCEABLE MAXIMUM CONTAMINANT LEVEL GOAL (MCLG) OF
ZERO FOR TCE IN DRINKING WATER AND IS CONSIDERING THE SAME MCLG FOR PCE. BECAUSE IT IS NOT POSSIBLE TO
ACCURATELY MEASURE LEVELS OF THESE COMPOUNDS BELOW THE MINIMUM DETECTION LIMIT, A FUTURE HEALTH RISK MAY
EXIST TO INDIVIDUALS CONSUMING WATER OVER A PROLONGED PERIOD OF TIME DURING WHICH PCE AND TCE ARE PRESENT,
BUT BELOW DETECTABLE LIMITS.
IN ADDITION, PROTECTION OF RESIDENTS FROM EXPOSURE TO THE CONTAMINANTS OF CONCERN IS DEPENDENT ON ADEQUATE
TREATMENT OF THE WATER. THE POTENTIAL FOR EXPOSURE EXISTS IN THAT FAILURE OF THE TREATMENT SYSTEM COULD
RESULT IN AN EXPOSURE PATHWAY THROUGH THE CITY'S DRINKING WATER. BASED ON THE POSSIBILITY OF FAILURE OF THE
AIR STRIPPERS, A POTENTIAL FUTURE RISK OF EXPOSURE TO PCE AND TCE VIA DRINKING WATER INGESTION EXISTS AT THE
SITE.
THE CALCULATED POTENTIAL CARCINOGENIC RISKS FOR FUTURE USE OF PRIVATE WELL WATER WERE APPROXIMATELY 1000
TIMES HIGHER THAN THOSE CALCULATED FOR USERS OF MUNICIPAL WATER, ASSUMING USERS WOULD BE EXPOSED TO MAXIMUM
CONTAMINANT CONCENTRATIONS IDENTIFIED IN GROUNDWATER AT THE SITE (SEE TABLE 5). BECAUSE INSTITUTIONAL
CONTROLS WERE NOT CONSIDERED ADEQUATE FOR PROTECTION FROM PRIVATE WELL USAGE, IT WAS DETERMINED THAT A
POTENTIAL FUTURE RISK OF EXPOSURE VIA GROUNDWATER EXISTS AT THE SITE.
THE POTENTIAL CANCER RISK TO INDIVIDUALS INHALING CONTAMINATED AIR EMANATING FROM THE STRIPPING TOWERS WAS
ESTIMATED BASED ON MODELING OF THE COMBINED CONTAMINANT PLUMES FROM THE CITY'S AIR STRIPPERS AND THE WAUSAU
CHEMICAL AIR STRIPPER. MODEL RESULTS FOR A WORST CASE SCENARIO FOR EXPOSURE OF RECEPTORS TO AIR BORNE
CONTAMINANTS ESTIMATED A CANCER RISK OF 1.7 X (10-6). THE ESTIMATED CURRENT RISK LEVEL IS NOT CONSIDERED TO
PRESENT AN APPRECIABLE HEALTH RISK TO RESIDENTS. HOWEVER, ALL ALTERNATIVES EVALUATED IN THE FS INCLUDE
TREATMENT OF OFF-GASES TO ELIMINATE ANY ADDITIONAL VOC EMISSIONS. IN ADDITION, THE SELECTED ALTERNATIVE
CALLS FOR ELIMINATION OF THE WAUSAU CHEMICAL AIR STRIPPER, WHICH WILL REDUCE THE LEVEL OF CONTAMINANTS IN THE
CONTAMINANT PLUME.
#DA
VII. DESCRIPTION OF ALTERNATIVES
A. RESPONSE OBJECTIVES
THE FEASIBILITY STUDY WAS INITIATED TO EVALUATE ALTERNATIVES FOR REMEDIATION OF THE GROUNDWATER CONTAMINATION
AND SOURCE AREAS AT THE SITE. BASED ON THE RISK ASSESSMENT, THREE PRIMARY SITE-SPECIFIC RESPONSE
OBJECTIVES WERE IDENTIFIED; 1) REDUCTION OF LONG-TERM EXPOSURE TO LOW LEVELS OF VOCS FROM INGESTION OF
DRINKING WATER; 2) PROTECTION FROM POTENTIAL FUTURE USE OF PRIVATE WELLS IN CONTAMINATED GROUNDWATER; AND, 3)
PROTECTION FROM EMISSIONS OF CONTAMINANTS FROM PROPOSED WATER TREATMENT SYSTEMS THAT RELEASE VOCS TO THE
ATMOSPHERE.
B. DEVELOPMENT OF ALTERNATIVES
IN DEVELOPING ALTERNATIVES FOR THIS SITE SEVERAL INITIAL ASSUMPTIONS WERE MADE REGARDING BASE LINE CONDITIONS
AT THE SITE. IT WAS ASSUMED THAT THE WEST SIDE EXTRACTION SYSTEM WOULD BE INSTALLED AND OPERATED AS
DESCRIBED IN THE INTERIM ROD. IT WAS ALSO DETERMINED, BASED ON COMPUTER MODELING OF THE SITE, THAT THE DEEP
TCE PLUME MOVING UNDER THE WISCONSIN RIVER TO CW3 WOULD BEST BE ADDRESSED AT THE SAME LOCATION AS THE
PROPOSED EXTRACTION WELL AT THE FORMER LANDFILL SOURCE. THEREFORE, IT WAS DETERMINED THAT AN INCREASE IN THE
PROPOSED MINIMUM PUMPING RATES CALLED FOR IN THE WEST SIDE EXTRACTION SYSTEM AND MODIFICATIONS TO THE
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MONITORING PLAN WOULD PROVIDE THE MOST EFFECTIVE REMEDIATION OF THIS CONTAMINANT PLUME.
AS DISCUSSED, THE REMAINING AREAS OF CONCERN FOR THE SITE INCLUDE THE SOURCE AREAS AND THE SHALLOW EAST SIDE
CONTAMINANT PLUME ORIGINATING FROM THE WAUSAU CHEMICAL SOURCE AREA. THE THREE IDENTIFIED SOURCE AREAS
INCLUDE THE FORMER CITY LANDFILL, THE WAUSAU CHEMICAL PROPERTY, AND THE WAUSAU ENERGY PROPERTY.
AT THE WAUSAU ENERGY SITE, PETROLEUM DERIVED COMPOUNDS HAVE BEEN FOUND IN GROUNDWATER SAMPLES DIRECTLY BELOW
THE SITE. ALTHOUGH TOLUENE, ETHYLENE, AND XYLENE WERE PREVIOUSLY DETECTED IN CW4, NO OFF-SITE MIGRATION OF
CONTAMINANTS WAS BEEN DETECTED DURING THE RI/FS, ALTHOUGH TOLUENE, ETHYLENE AND XYLENE WERE PREVIOUSLY
DETECTED IN CW4. BECAUSE OFF-SITE MONITORING DOES NOT INDICATE GROUNDWATER IMPACTS FROM THE WAUSAU ENERGY
SOURCE AT PRESENT, GROUNDWATER REMEDIATION AT WAUSAU ENERGY IS NOT ADDRESSED AS PART OF THE FINAL REMEDY.
HOWEVER, CONTAMINATED SOILS FOUND AT WAUSAU ENERGY WILL BE ADDRESSED UNDER THE DISCUSSION OF SOURCE CONTROL.
A VARIETY OF TECHNOLOGIES TO ADDRESS RESPONSE OBJECTIVES WERE IDENTIFIED FOR FURTHER CONSIDERATION INCLUDING
SEVERAL FOR REMEDIATION OF SOURCE AREAS. HOWEVER, CONSIDERING THE NATURE OF THE SOURCE AREAS, AND THE
CONTAMINANTS PRESENT, ONLY ONE SOURCE CONTROL TECHNOLOGY (SOIL VAPOR EXTRACTION) WAS RETAINED FROM THE
SCREENING OF TECHNOLOGIES.
FOLLOWING SCREENING OF TECHNOLOGIES, ALTERNATIVES WERE DEVELOPED AND SCREENED FOR APPROPRIATENESS BASED ON
RESPONSE OBJECTIVES. FIVE ALTERNATIVES REMAINED AFTER SCREENING AND WERE SUBJECTED TO DETAILED ANALYSIS
USING THE NINE EVALUATION CRITERIA DEVELOPED UNDER THE NATIONAL CONTINGENCY PLAN (NCP). TABLE 6 LIstS THE
FIVE ALTERNATIVES.
TABIiE 6
REMEDIAL ACTION ALTERNATIVES
ALTERNATIVE 1
NO ACTION
ALTERNATIVE 2
GROUNDWATER EXTRACTION AND
TREATMENT WITH AIR STRIPPING AND
DISCHARGE TO THE WISCONSIN RIVER
ALTERNATIVE 3
IN-SITU BIORECLAMATION WITH
PARTIAL ABOVE GROUND TREATMENT
AND DISCHARGE TO THE WISCONSIN
RIVER
ALTERNATIVE 4
ALTERNATIVE 5
IN-SITU BIORECLAMATION
ACTIVE SOURCE CONTROL-SOIL VAPOR
EXTRACTION
C. ALTERNATIVES
ALTERNATIVE 1 - NO ACTION
THE NO ACTION ALTERNATIVE IS EVALUATED AS REQUIRED BY THE NCP.
WOULD BE TAKEN BEYOND THE INTERIM REMEDY.
UNDER THIS ALTERNATIVE, NO RESPONSE ACTION
THE INTERIM REMEDY EXTRACTION WELL WILL PROVIDE A BARRIER TO CONTAMINANT MIGRATION FROM THE LANDFILL SOURCE
TO CW6, ULTIMATELY RESULTING IN THE ELIMINATION OF CONTAMINANT IMPACT AT THIS WELL. THE TIME TO ACHIEVE
PROTECTION OF CW6 UNDER THIS ALTERNATIVE DEPENDS ON THE RATE OF AQUIFER PURGING PROVIDED BY WELL CW6 PUMPING.
COMPUTER SIMULATION OF THE NO ACTION ALTERNATIVE FOR THE LANDFILL SOURCE SHOWS THAT A GROUNDWATER DIVIDE
WOULD BE PRESENT IN THE VICINITY OF THE PONDED AREA IN BOS CREEK BETWEEN CW6 AND THE LANDFILL EXTRACTION
WELL. CONTAMINANTS ON EITHER SIDE OF THIS DIVIDE WOULD MIGRATE NORTH TO CW6 OR SOUTH TO THE EXTRACTION WELL.
GIVEN THE PUMPING RATES ASSUMED FOR THESE SIMULATIONS AND THE INITIAL MASS DISTRIBUTION, A TIME PERIOD OF
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APPROXIMATELY 10 YEARS IS ESTIMATED TO BE NECESSARY TO ACHIEVE CONTAMINANT CONCENTRATIONS BELOW THE MCL FOR
TCE (5 UG/L) AT CW6. THE PERIOD DURING WHICH CW6 DRAWS IN CONTAMINANTS FROM THE LANDFILL SOURCE IS ESTIMATED
TO BE APPROXIMATELY 20 YEARS UNDER PROJECTED PUMPING CONDITIONS.
THE NO ACTION SIMULATION FOR THE LANDFILL SOURCE SHOWS THAT THE EXTRACTION WELL AT THE LANDFILL WOULD ALSO
STOP ADDITIONAL MIGRATION OF CONTAMINATION BENEATH THE WISCONSIN RIVER TO CW3. A PERIOD OF APPROXIMATELY 6
YEARS IS ESTIMATED TO OBTAIN CONTAMINANT CONCENTRATIONS AT CW3 LESS THAN 5 UG/L.
THE SIMULATED GROUNDWATER PIEZOMETRIC SURFACE CONTOURS FOR THE EAST WELL FIELD ARE SHOWN ON FIGURE 6. THE
MAP INDICATES AN AREA OF HYDRAULIC INFLUENCE WHICH EXTENDS SOUTH OF THE WAUSAU CHEMICAL PROPERTY DUE
PRIMARILY TO PUMPING OF CW3. WITH NO CW4 PUMPING, THE SHALLOW EAST SIDE CONTAMINANT PLUMES LIE WITHIN THIS
AREA OF INFLUENCE. THE SIMULATION SHOWS THE CONTAMINANT MASS REACHING CW3 FROM THE WAUSAU CHEMICAL SOURCES
WOULD RESULT IN CONCENTRATIONS CONSISTENTLY LESS THAN 5 UG/L AFTER APPROXIMATELY 6.3 YEARS.
THE TIME DURING WHICH CW3 WOULD DRAW IN CONTAMINANTS FROM EITHER EAST SIDE OR WEST SIDE SOURCES IS ESTIMATED
TO BE APPROXIMATELY 15 YEARS. IT WAS ASSUMED THAT THE PHASE I REMEDY EXTRACTION WELL NORTH OF THE LANDFILL
WOULD BE IN OPERATION, AND THAT CONTAMINANTS IN UNSATURATED ZONE SOILS AT WAUSAU CHEMICAL WOULD REPRESENT A
GROUNDWATER CONTAMINANT SOURCE THAT DECLINES IN STRENGTH OVER AN APPROXIMATELY 8-YEAR PERIOD.
PROBABLE ARARS FOR THE NO ACTION ALTERNATIVE ARE SUMMARIZED IN TABLE 7. CHEMICAL-SPECIFIC ARARS IDENTIFIED
INCLUDE THOSE RELATED TO DRINKING WATER, GROUNDWATER, SURFACE WATER AND AIR QUALITY. DRINKING WATER MCLS
FOR VOCS CAN BE MET BY STRIPPING TOWER TREATMENT, AS EVIDENCED BY ACTUAL PERFORMANCE DATA. THE NO ACTION
ALTERNATIVE WOULD NOT COMPLY WITH CHAPTER NR 140 REQUIREMENTS FOR RESPONSES WHERE ENFORCEMENT STANDARDS ARE
EXCEEDED. AIR EMISSION LIMITS ARE NOT ANTICIPATED TO BE EXCEEDED BY ANY OF THE IDENTIFIED SOURCES.
THE ONLY LOCATION-SPECIFIC ARAR IDENTIFIED INVOLVES POTENTIAL FUTURE REQUIREMENTS THAT MAY BE IMPLEMENTED
UNDER A WELLHEAD PROTECTION AREA PROGRAM. NO AREA HAS BEEN DESIGNATED TO DATE AND NO REQUIREMENTS HAVE BEEN
IDENTIFIED. ACTION-SPECIFIC ARARS IDENTIFIED RELATE TO PROPERTY USE AT THE LANDFILL AND UNCONTROLLED
EMISSION OF TOXIC ORGANICS FROM SOURCE AREAS.
THERE IS NO COST OR OPERATION AND MAINTENANCE (O&M) ASSOCIATED WITH THE NO ACTION ALTERNATIVE. ANNUAL COSTS
TO OPERATE THE PRESENT AIR STRIPPER WERE NOT CONSIDERED AS O&M UNDER THIS ALTERNATIVE.
ALTERNATIVE 2 - GROUNDWATER EXTRACTION/ABOVE GROUND TREATMENT
ALTERNATIVE 2 INVOLVES INSTALLATION OF A GROUNDWATER EXTRACTION SYSTEM TO ADDRESS THE SHALLOW GROUNDWATER
CONTAMINATION IN THE EAST WELL FIELD ORIGINATING FROM THE WAUSAU CHEMICAL FACILITY. A GROUNDWATER EXTRACTION
AND TREATMENT SYSTEM WOULD BE INSTALLED ON THE WAUSAU CHEMICAL PROPERTY TO EXTRACT CONTAMINATED WATER IN
CLOSE PROXIMITY TO THE AREA OF GREATEST SOIL CONTAMINATION (SEE FIGURE 7). THE SYSTEM WOULD INCLUDE A
CLUSTER OF WELLS DESIGNED TO EXTEND THE ZONE OF INFLUENCE BENEATH THE CITY FILTRATION PLANT AND THE WAUSAU
CHEMICAL BUILDING, AS WELL AS TO THE EAST OF THE FACILITY WHERE CONTAMINANTS HAVE MIGRATED DUE TO THE EFFECTS
OF AQUIFER RECHARGE FROM THE WISCONSIN RIVER.
EXTRACTED WATER WOULD BE PUMPED TO AN AIR STRIPPER FOR TREATMENT OF VOCS PRIOR TO DISCHARGE TO THE WISCONSIN
RIVER. OFF-GAS TREATMENT WOULD BE INCLUDED IN THE TREATMENT PROCESS AND WOULD INVOLVE VAPOR PHASE ACTIVATED
CARBON UNITS TO TREAT GASES AND OFF SITE REGENERATION OF CARBON AND DESTRUCTION OF CONTAMINANTS. IT IS
ESTIMATED THAT THE SYSTEM FLOW RATE WOULD BE APPROXIMATELY 300-500 GPM.
IMPLEMENTATION OF THIS ALTERNATIVE IS EXPECTED TO LIMIT MIGRATION OF CONTAMINANTS FROM WAUSAU CHEMICAL TO
CW3. CONTAMINANT TRANSPORT SIMULATIONS OF THIS ALTERNATIVE SHOWS THAT AT TOTAL SYSTEM PUMPING RATES OF 200
AND 500 GPM, CONTAMINANT CONCENTRATIONS AT CW3 RESULTING FOR MIGRATION FORM THE WAUSAU CHEMICAL SOURCE WOULD
BE LESS THAN 5 UG/L IN APPROXIMATELY 5.2 YEARS. HOWEVER, COMPLETE RESTORATION OF THE AQUIFER ON THE EAST
SIDE OF THE RIVER WOULD REQUIRE 12 YEARS.
CONTAMINATION IN THE DEEP GROUNDWATER PLUME ORIGINATING AT THE FORMER CITY LANDFILL/MARATHON ELECTRIC SOURCE
AREA IS NOT ANTICIPATED TO BE INFLUENCED BY PUMPING OF THE EAST SIDE EXTRACTION WELL SYSTEM. THUS, THE TIME
TO ACHIEVE PROTECTION OF CW3 UNDER THIS ALTERNATIVE IS NOT ANTICIPATED TO BE SUBSTANTIALLY DIFFERENT FROM
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THAT ESTIMATED UNDER THE NO ACTION ALTERNATIVE, BECAUSE THE TIME TO ACHIEVE AQUIFER PURGING UNDER BOTH
ALTERNATIVES IS DETERMINED BY THE TIME REQUIRED TO REMEDIATE THE DEEP TCE PLUME. HOWEVER, THE MAGNITUDE OF
CONTAMINANT CONCENTRATIONS AFFECTING PRODUCTION WELL CW3 IS EXPECTED TO DECREASE, BECAUSE THE CONTRIBUTION
OF CONTAMINANTS FROM THE EAST SIDE SOURCE WILL BE REDUCED.
COSTS FOR ALTERNATIVE 2 ARE SUMMARIZED IN TABLE 12. MAJOR CAPITAL COST ITEMS INCLUDE GROUNDWATER EXTRACTION
WELLS AND HEADER SYSTEM, PUMPS, CONTROLS, STRIPPING TOWER AND DISCHARGE LINE. MAJOR OPERATION AND
MAINTENANCE ITEMS INCLUDE ENERGY COSTS, SAMPLING AND MONITORING, ANALYTICAL LABORATORY, ROUTINE SYSTEMS
INSPECTION AND MAINTENANCE, AND REPORTING. CAPITAL COSTS ARE ESTIMATED TO BE $480,000. ANNUAL OPERATION
AND MAINTENANCE COSTS ARE ESTIMATED TO BE APPROXIMATELY $120,000. THE 10-YEAR PRESENT WORTH (10% DISCOUNT
RATE) ASSOCIATED WITH THE ABOVE COSTS IS $1,330,000.
PROBABLE ARARS FOR ALTERNATIVE 2 ARE SUMMARIZED IN TABLE 8. CHEMICAL-SPECIFIC ARARS INCLUDE DRINKING WATER,
GROUNDWATER, SURFACE WATER AND AIR QUALITY STANDARDS, CRITERIA OR LIMITS. THESE INCLUDE DRINKING WATER MCLS
AND NR 140 STANDARDS. DRINKING WATER MCLS FOR VOCS CAN BE MET BY THE WATER UTILITY. THE PROPOSED GROUNDWATER
RESPONSE ACTIONS WOULD SATISFY RESPONSE REQUIREMENTS OF NR 140. MEETING WATER QUALITY-BASED EFFLUENT LIMITS
ESTABLISHED TO MEET WATER QUALITY CRITERIA SHOULD BE FEASIBLE USING PACKED TOWER STRIPPING. MEETING
COMPOUND-SPECIFIC LIMITS FOR VOC EMISSIONS TO AIR WOULD BE FEASIBLE BASED ON ANTICIPATED CONCENTRATIONS AND
PUMPING RATES, REGARDLESS OF WHETHER OR NOT OFF-GAS CONTROLS ARE USED.
LOCATION-SPECIFIC ARARS INCLUDE POSSIBLE WELLHEAD PROTECTION REQUIREMENTS, AND FLOODPLAIN ACTIVITY
REQUIREMENTS. ACTION-SPECIFIC ARARS INCLUDE REQUIREMENTS FOR WELL CONSTRUCTION AND PLUMBING SYSTEM
STANDARDS, TREATMENT SYSTEM PLAN REVIEW, OBTAINING A SURFACE WATER DISCHARGE PERMIT, VOC EMISSIONS LIMITS AND
CONSTRUCTION AND INDUSTRIAL SAFETY. NO DIFFICULTIES IN ACHIEVING COMPLIANCE WITH ANY OF THESE HAVE BEEN
IDENTIFIED.
IMPLEMENTATION OF THIS ALTERNATIVE IS NOT EXPECTED TO BE A PROBLEM. THE TECHNOLOGY IS READILY AVAILABLE,
CONVENTIONAL, AND WELL DEMONSTRATED. CONSTRUCTION IS STRAIGHT FORWARD AND NO UNUSUAL FEATURES ARE ANTICIPATED
TO BE REQUIRED FOR THE SYSTEM. COORDINATION BETWEEN Us EPA AND THE CITY OF WAUSAU WILL BE REQUIRED TO
ACCOMPLISH IMPLEMENTATION OF THE SYSTEM.
ALTERNATIVE 3 - IN-SITU BIORECLAMATION WITH PARTIAL TREATMENT AND DISCHARGE
ALTERNATIVE 3 IS AN IN-SITU METHOD FOR REMEDIATION OF THE SHALLOW EAST SIDE GROUNDWATER CONTAMINANT PLUME.
GROUNDWATER WOULD BE EXTRACTED, A PORTION WOULD BE TREATED AND DISCHARGED TO THE WISCONSIN RIVER AND THE
REMAINDER WOULD BE SUPPLEMENTED WITH NUTRIENTS AND RECHARGED TO THE AQUIFER TO ENHANCE MICROBIALLY-MEDIATED
DEGRADATION OF CONTAMINANTS IN-SITU.
A LINE OF GROUNDWATER EXTRACTION WELLS WOULD BE INSTALLED AROUND THE NORTH AND EAST PORTIONS OF THE WAUSAU
CHEMICAL PROPERTY. A CONCEPTUAL SYSTEM LAYOUT IS SHOWN ON FIGURE 8. THE PLACEMENT OF BARRIER WELLS IS
INTENDED TO SURROUND THE SECTION (DOWNGRADIENT OF THE WAUSAU CHEMICAL SOURCES) OF THE PLUME WHERE VOLATILE
CHLORINATED HYDROCARBON CONCENTRATIONS GREATER THAN APPROXIMATELY 200 UG/L WERE OBSERVED. EXTRACTED
GROUNDWATER WOULD BE PUMPED TO A COMMON HEADER. THE HEADER WOULD CONVEY WATER BACK TOWARD THE TREATMENT
SYSTEM. THE FLOW WOULD BE SPLIT BETWEEN THE TREATMENT SYSTEM AND RECHARGE TO GROUNDWATER.
FOR A GROUNDWATER EXTRACTION RATE OF 500 GPM, APPROXIMATELY 300 GPM WOULD BE TREATED USING VOC STRIPPING AND
DISCHARGED TO THE WISCONSIN RIVER. A VOC STRIPPING TOWER WITH OFF-GAS CONTROLS WOULD BE USED FOR
TREATMENT. CARBON ADSORPTION WOULD BE PROVIDED FOR OFF-GAS TREATMENT.
THE 200 GPM NOT TREATED ABOVE GROUND AND DISCHARGED WOULD BE SUPPLEMENTED WITH NUTRIENTS AND RECHARGED OVER
THE SOUTHERN END OF THE WAUSAU CHEMICAL PROPERTY. INFILTRATION TRENCHES FILLED WITH GRAVEL WOULD EFFECTIVELY
DISTRIBUTE WATER OVER THE AREA. NUTRIENTS SUCH AS NITROGEN OR PHOSPHORUS WOULD BE ADDED. WHERE AEROBIC
CONDITIONS ARE DESIRED, HYDROGEN PEROXIDE WOULD BE FED. A CARBON AND ENERGY SOURCE SUCH AS A METHANOL MAY BE
REQUIRED TO SUPPORT HETEROTROPHIC GROWTH.
LABORATORY AND FIELD STUDY WOULD BE REQUIRED TO CONFIRM FEASIBILITY AT THE SITE AND DETERMINE THE REQUIRED
OPERATING ENVIRONMENT AND CONDITIONS. IT IS ANTICIPATED THAT PLANNING, EXECUTION AND ANALYSIS OF LABORATORY
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STUDIES COULD BE ACCOMPLISHED WITHIN A 6-MONTH PERIOD, AND THAT PLANNING, EXECUTION AND ANALYSIS OF FIELD
PILOT TESTING PROGRAM COULD BE ACCOMPLISHED WITHIN A 1.5-YEAR PERIOD, DEPENDING ON THE SCOPE AND COMPLEXITY
OF STUDIES AND ON THE OUTCOME OF EARLY TEST PHASE ACTIVITIES. OVERALL, A TWO-YEAR PERIOD COULD BE REQUIRED
FOR TESTING AND DEMONSTRATION.
TECHNOLOGIES DESCRIBED IN THIS ALTERNATIVE ARE EXPECTED TO PROVIDE PROTECTION OF CW3 BY CREATING A BARRIER TO
THE MIGRATION OF MOST OF THE CONTAMINANTS IN THE SHALLOW EAST SIDE PLUME, IN ADDITION TO AQUIFER RESTORATION.
THIS ALTERNATIVE IS NOT EXPECTED TO AFFECT THE DEEP CONTAMINANT PLUME ORIGINATING ON THE WEST SIDE.
COMPUTER SIMULATION OF THE ALTERNATIVE SHOWS THAT THE PROPOSED LINE OF EXTRACTION WELLS CAN CREATE AN
EFFECTIVE HYDRAULIC BARRIER TO CONTAMINANT MIGRATION TO CW3 IF PUMPING RATES ARE HIGH ENOUGH. THE SIMULATED
HEAD CONTOUR MAP SHOWN ON FIGURE 6 SHOWS THIS OCCURS AT A TOTAL SYSTEM PUMPING RATE OF 500 GPM AND AN
INFILTRATION RATE OF 200 GPM AT THE SOURCE. CONTAMINANT TRANSPORT SIMULATION SHOWS THAT PCE CONCENTRATIONS
AT CW3 WOULD DECREASE BELOW 5 UG/L AFTER APPROXIMATELY 2.5 YEARS. COMPLETE AQUIFER PURGE TIME FOR THE EAST
SIDE GROUNDWATER UNDER THIS ALTERNATIVE COULD NOT BE ESTIMATED USING THE CONTAMINANT TRANSPORT MODEL. THE
SIMULATION SHOWS THAT THE GROUNDWATER MOUND RESULTING FROM THE RECHARGE MAY FORCE A SMALL AMOUNT (Less Than 1
percent) OF CONTAMINATION TO MIGRATE AROUND THE EAST SIDE OF THE EXTRACTION SYSTEM. HOWEVER, THE MASS NOT
CAPTURED IS NOT LIKELY TO RESULT IN DETECTABLE CONCENTRATIONS AT CW3. PUMPING AT LOWER RATES OR WITH WIDELY
SPACED WELLS MAY NOT PROVIDE THE DESIRED HYDRAULIC CONTROL.
COSTS FOR ALTERNATIVE 3 ARE SUMMARIZED IN TABLE 13. MAJOR CAPITAL COST ITEMS INCLUDE LABORATORY AND FIELD
TESTING PROGRAMS, SYSTEM REVIEW AND APPROVAL, EXTRACTION WELL AND HEADER SYSTEM, STRIPPING TOWER, CARBON
ADSORBER, FOUNDATIONS, NUTRIENT FEEDING SYSTEM, RECHARGE TRENCH AND PIPING, CONTROLS AND UTILITIES AND
DISCHARGE PIPING. MAJOR OPERATION AND MAINTENANCE COST ITEMS INCLUDE ENERGY COSTS, SAMPLING AND MONITORING,
ANALYTICAL LABORATORY, ROUTINE SYSTEMS INSPECTION AND MAINTENANCE, AND REPORTING. FOR COSTING PURPOSES, IT
IS ASSUMED A TIME PERIOD OF SIX YEARS WOULD BE REQUIRED. CAPITAL COSTS ARE ESTIMATED TO BE $990,000. THE
ANNUAL OPERATION AND MAINTENANCE COSTS ARE ESTIMATED TO BE APPROXIMATELY $160,000. THE 6-YEAR PRESENT WORTH
(10 percent DISCOUNT RATE) ASSOCIATED WITH THE ABOVE COSTS IS $1,710,000.
PROBABLE ARARS FOR ALTERNATIVE 3 ARE SUMMARIZED IN TABLE 9. CHEMICAL-SPECIFIC ARARS FOR DRINKING WATER,
GROUNDWATER, SURFACE WATER AND AIR WERE IDENTIFIED FOR THIS ALTERNATIVE. THESE INCLUDE DRINKING WATER MCLS
AND NR 140 GROUNDWATER STANDARDS. DRINKING WATER MCLS CAN BE MET BY STRIPPING TOWER TREATMENT AT THE WATER
UTILITY. THE AQUIFER RESTORATION EFFORT WOULD BE CONSISTENT WITH NR 140 REQUIREMENTS FOR REMEDIAL RESPONSES
TO GROUNDWATER CONTAMINATION. SURFACE WATER CRITERIA COMPLIANCE WOULD BE FEASIBLE USING STRIPPING TOWER
TREATMENT TO MEET WATER QUALITY-BASED EFFLUENT LIMITS FOR WATER DISCHARGED TO THE WISCONSIN RIVER. VOC
EMISSION RATE LIMITS FOR SPECIFIC COMPOUNDS WOULD BE ATTAINABLE FOR THE STRIPPING TOWER EMISSIONS.
LOCATION-SPECIFIC ARARS INCLUDE FLOODPLAIN AND POSSIBLE WELLHEAD PROTECTION AREA REQUIREMENTS.
ACTION-SPECIFIG ARARS FOR THE GROUNDWATER EXTRACTION, TREATMENT AND DISCHARGE SYSTEMS ARE THE SAME AS FOR
ALTERNATIVE 2. NO PARTICULAR COMPLIANCE DIFFICULTIES ARE ANTICIPATED. TO ACHIEVE COMPLIANCE WITH STATE
REQUIREMENTS REGARDING INTRODUCTION OF MATERIALS INTO GROUNDWATER OR ON LAND (INCLUDING INJECTION WELL AND
INFILTRATION SYSTEM RESTRICTIONS), A DEMONSTRATION THAT SIGNIFICANT ADVERSE EFFECTS WILL NOT RESULT WOULD BE
REQUIRED.
IMPLEMENTATION OF THE EXTRACTION WELLS AND ABOVE GROUND TREATMENT PORTION OF THIS ALTERNATIVE IS NOT EXPECTED
TO BE A PROBLEM. THE MAJOR UNCERTAINTY WITH THIS TECHNOLOGY IS RELATED TO THE ABILITY TO STIMULATE BACTERIA
TO DEGRADE THE COMPOUNDS OF CONCERN. THE TECHNOLOGY IS NOT WELL DEMONSTRATED FOR THE CONTAMINANTS FOUND AT
THE SITE.
ALTERNATIVE 4 - IN-SITU BIORECLAMATION
ALTERNATIVE 4 IS AN IN-SITU METHOD FOR REMEDIATION OF THE SHALLOW EAST SIDE GROUNDWATER UTILIZING
BIODEGRADATION OF CONTAMINANTS IN THE GROUNDWATER. ALTERNATIVE 4 IS SIMILAR TO ALTERNATIVE 3, EXCEPT ALL
EXTRACTED GROUNDWATER WOULD BE RECHARGED BACK TO THE AQUIFER. THIS ALTERNATIVE PROVIDES FOR RAPID
RESTORATION OF THE AQUIFER AND ELIMINATES THE COSTS ASSOCIATED WITH ABOVE GROUND TREATMENT AS WITH
ALTERNATIVE 3.
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UNDER ALTERNATIVE 4, GROUNDWATER WOULD BE EXTRACTED, SUPPLEMENTED WITH NUTRIENTS AND RECHARGED TO THE AQUIFER
TO ENHANCE MICROBIALLY-MEDIATED CONTAMINANT DEGRADATION IN-SITU. A LINE OF GROUNDWATER EXTRACTION WELLS
WOULD BE INSTALLED AROUND THE NORTHERN AND EASTERN PORTIONS OF THE WAUSAU CHEMICAL PROPERTY. THE CONCEPTUAL
EXTRACTION AND RECHARGE SYSTEM LAYOUT IS THE SAME AS THAT DEVELOPED FOR ALTERNATIVE 3 (FIGURE 8). THE
GROUNDWATER EXTRACTION AND RECHARGE RATES AND CONSIDERATIONS REGARDING THE ADDITION OF NUTRIENTS AND OTHER
ENHANCEMENTS TO RECHARGE WATER ARE THE SAME AS THOSE DISCUSSED FOR ALTERNATIVE 3.
COMPUTER SIMULATION OF THE ALTERNATIVE SHOWS THAT THE PROPOSED LINE OF EXTRACTION WELLS CAN NOT PROVIDE
COMPLETE HYDRAULIC CONTROL OF THE EXTRACTION/RECHARGE SYSTEM AT ANY PUMPING RATE. CONTAMINANT TRANSPORT
SIMULATION SHOWS THAT PCE CONCENTRATIONS AT CW3 WOULD DECREASE BELOW 5 UG/L AFTER APPROXIMATELY 2.5 YEARS.
AS WITH ALTERNATIVE 3, COMPLETE AQUIFER PURGE TIME FOR THE EAST SIDE GROUNDWATER UNDER THIS ALTERNATIVE
COULD NOT BE ESTIMATED USING THE CONTAMINANT TRANSPORT MODEL.
THE SIMULATION ALSO SHOWS THAT THE GROUNDWATER MOUND RESULTING FROM THE RECHARGE CAUSES APPROXIMATELY 5% OF
THE CONTAMINANT MASS TO MIGRATE AROUND THE EAST SIDE OF THE EXTRACTION SYSTEM TO CW3 (SEE FIGURE 6). THE
ACTUAL RECAPTURE EFFICIENCY WILL DEPEND ON SUCH FACTORS AS THE SPECIFIC SYSTEM CONFIGURATION, LOCALIZED
VARIATIONS IN AQUIFER PROPERTIES, EXTRACTION/RECHARGE RATES AND OPERATING CONDITIONS, AND LOCAL HYDROLOGIC
FACTORS, SUCH AS PRECIPITATION, RUNOFF AND INFILTRATION RATES. ACHIEVING A 100 PERCENT RECAPTURE EFFICIENCY
IS NOT CONSIDERED FEASIBLE.
COSTS FOR ALTERNATIVE 4 ARE SUMMARIZED IN TABLE 14. MAJOR CAPITAL COST ITEMS INCLUDE LABORATORY AND FIELD
TESTING PROGRAMS, SYSTEM REVIEW AND APPROVAL, EXTRACTION WELL AND HEADER SYSTEM, NUTRIENT FEEING SYSTEM,
RECHARGE TRENCH AND PIPING, CONTROLS AND UTILITIES. MAJOR OPERATION AND MAINTENANCE COST ITEMS INCLUDE
ENERGY COSTS, SAMPLING AND MONITORING, ANALYTICAL LABORATORY, ROUTINE SYSTEMS INSPECTION AND MAINTENANCE, AND
REPORTING. AS WITH ALTERNATIVE 3, REMEDIATION PERIOD ESTIMATES WERE NOT OBTAINED USING THE CONTAMINANT
TRANSPORT MODEL. IT WAS ASSUMED THAT ALTERNATIVE 4 WOULD REQUIRE MORE TIME THAN ALTERNATIVE 3, AND LESS TIME
THAN ALTERNATIVE 2 (DUE TO IN-PLACE CONTAMINANT DEGRADATION) TO ACHIEVE REMEDIAL OBJECTIVES. A PERIOD OF 9
YEARS WAS ASSUMED FOR COSTING PURPOSES. CAPITAL COSTS ARE ESTIMATED TO BE $710,000. THE ANNUAL OPERATION
AND MAINTENANCE COSTS ARE ESTIMATED TO BE APPROXIMATELY $112,000. THE 9-YEAR PRESENT WORTH (10% DISCOUNT
RATE) ASSOCIATED WITH THE ABOVE COSTS IS $1,380,000.
PROBABLE ARARS FOR ALTERNATIVE 4 ARE SUMMARIZED IN TABLE 10. CHEMICAL-SPECIFIC ARARS FOR DRINKING WATER,
GROUNDWATER, SURFACE WATER AND AIR WERE IDENTIFIED FOR THIS ALTERNATIVE. THESE INCLUDE DRINKING WATER MCLS
AND NR 140 GROUNDWATER STANDARDS. THE AQUIFER RESTORATION EFFORT WOULD BE CONSISTENT WITH REQUIREMENTS FOR
RESPONSES TO GROUNDWATER CONTAMINATION UNDER NR 140.
LOCATION-SPECIFIC ARARS INCLUDE FLOODPLAIN AND POSSIBLE WELLHEAD PROTECTION AREA REQUIREMENTS.
ACTION-SPECIFIG ARARS FOR THE GROUNDWATER EXTRACTION, TREATMENT AND DISCHARGE SYSTEMS ARE THE SAME AS FOR
ALTERNATIVE 3.
IMPLEMENTATION OF THE EXTRACTION WELLS, TRENCHING, AND DISCHARGE PORTION OF THIS ALTERNATIVE IS NOT EXPECTED
TO BE A PROBLEM. THE MAJOR UNCERTAINTY WITH THIS TECHNOLOGY IS RELATED TO THE ABILITY TO STIMULATE EXISTING
BACTERIA TO DEGRADE THE COMPOUNDS OF CONCERN IN THE GROUNDWATER. THIS TECHNOLOGY IS NOT WELL DEMONSTRATED
FOR THE CONTAMINANTS FOUND AT THE SITE.
ALTERNATIVE 5 - ACTIVE SOURCE CONTROL-SOIL VAPOR EXTRACTION
ALTERNATIVE 5 IS A SOURCE CONTROL ALTERNATIVE UTILIZING IN-SITU SOIL VAPOR EXTRACTION (SVE) TO REMOVE
CONTAMINANTS FROM UNSATURATED SOILS THEREBY REDUCING THE POTENTIAL FOR FUTURE CONTAMINANT RELEASES TO
GROUNDWATER. CONTAMINANTS VACUUMED FROM THE SOIL, IN THE VAPOR PHASE, WOULD BE TREATED USING VAPOR PHASE
CARBON UNITS, PRIOR TO RELEASE TO THE ATMOSPHERE. THE SCOPE OF ALTERNATIVE 5 INCLUDES REMEDIATION OF
UNSATURATED SOILS AT THE FORMER CITY LANDFILL/MARATHON ELECTRIC PROPERTY, WAUSAU CHEMICAL AND WAUSAU ENERGY.
FOR THE FORMER LANDFILL AREA, SOIL GAS EXTRACTION WELLS WOULD BE INSTALLED WITHIN THE LIMITS OF THE FILL IN
THE NORTHERN PORTION OF THE LANDFILL WHERE THE HIGHEST VOC CONCENTRATIONS HAVE BEEN OBSERVED. A CONCEPTUAL
SYSTEM LAYOUT IS SHOWN ON FIGURE 9. A HEADER PIPE WOULD BE INSTALLED TO CONNECT THE WELLS TO AN INDUCTION
FAN BLOWER. THE BLOWER AND CONTROL PANEL WOULD BE HOUSED IN A SMALL SHED. IT IS ANTICIPATED THAT AIR
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RECHARGE WELLS WOULD BE REQUIRED AND ARE INCLUDED IN THE DESIGN & COST OF THE ALTERNATIVE.
A SIMILAR TYPE OF SOIL GAS EXTRACTION SYSTEM WOULD BE INSTALLED ON THE WAUSAU CHEMICAL PROPERTY. SOIL GAS
WOULD BE EXTRACTED NEAR THE FORMER TANK STORAGE AREA. THIS AREA IS NEAR THE CENTER OF HIGH SOIL GAS VOC
CONCENTRATIONS OBSERVED AT THE SITE. A SECOND EXTRACTION AREA WOULD BE LOCATED NEAR THE NORTH END OF THE
BUILDING. A HEADER WOULD CONNECT THE EXTRACTION WELLS TO A COMMON BLOWER. AIR RECHARGE WELLS WOULD ALSO BE
ANTICIPATED FOR THIS SYSTEM. CONCEPTUAL LAYOUT IS SHOWN ON FIGURE 10. PILOT STUDY RESULTS INDICATE A RADIUS
OF INFLUENCE OF APPROXIMATELY 85 FEET WAS OBTAINED AT A GAS EXTRACTION RATE OF 72 SCFM. A SOIL GAS
EXTRACTION SYSTEM WOULD ALSO BE INSTALLED AT THE WAUSAU ENERGY PROPERTY ON THE SOUTH SIDE OF THE BUILDING.
SOIL TYPES ENCOUNTERED IN ON-SITE BORINGS WERE SIMILAR TO THOSE ENCOUNTERED AT SEVERAL WAUSAU CHEMICAL SITE
BORINGS AND IT IS THEREFORE, ASSUMED THAT THE RADIUS OF INFLUENCE WOULD BE SUFFICIENT TO COVER THE ENTIRE
FACILITY.
TECHNOLOGIES DESCRIBED IN THIS ALTERNATIVE WOULD REDUCE THE TIME REQUIRED TO MEET RESPONSE OBJECTIVES FOR
GROUNDWATER CLEAN-UP, BECAUSE THERE WILL BE A REDUCTION IN CONTAMINANT LOADING TO THE AQUIFER, BY REDUCING
CONTAMINANT LEVELS IN THE UNSATURATED ZONE SOILS. HOWEVER, SUBSTANTIAL REDUCTIONS IN EXISTING CONTAMINANT
CONCENTRATIONS IN GROUNDWATER WOULD NOT BE EXPECTED TO OCCUR AS A RESULT OF VAPOR EXTRACTION AT THE SOURCE.
BASED ON COMPUTER SIMULATIONS DURING DEVELOPMENT OF THE FS, IT WAS SHOWN THAT EXTRACTION OF GROUNDWATER ON
THE EAST SIDE IN THE VICINITY OF THE WAUSAU CHEMICAL SOURCE AREA WOULD CREATE A GROUNDWATER DIVIDE WHERE
CONTAMINANTS WOULD GET "HUNG UP" DUE TO COMPETITION FOR WATER BETWEEN CW3 AND THE EXTRACTION SYSTEM (SEE
DISCUSSION UNDER ALTERNATIVE 2). BECAUSE OF THIS PHENOMENON, EXTRACTING GROUNDWATER AT THE SOURCE RESULTS
IN A LONGER PERIOD TO PURGE THE AQUIFER THAN ALLOWING CONTAMINANTS TO FLOW TO THE CURRENTLY OPERATING CITY
SUPPLY WELLS. IT WAS, THEREFORE, DETERMINED THAT CITY SUPPLY WELLS CW6 AND CW3 WOULD BE INCORPORATED INTO
THE SOURCE CONTROL ALTERNATIVE AS THE MEANS FOR ADDRESSING GROUNDWATER CONTAMINATION REMEDIATION.
COMPUTER MODELING OF THIS ALTERNATIVE WAS PERFORMED BY DECREASING THE CONTAMINANT LOADING RATES FROM SOILS TO
ZERO AFTER 1.5 YEARS TO SIMULATE REMOVAL OF THE SOURCES. TWO DIFFERENT COMPUTER SIMULATIONS WERE PERFORMED
TO DETERMINE THE OPTIMUM PUMPAGE RATES FOR THE CITY'S SUPPLY WELLS CW3 AND CW6. IT WAS DETERMINED THAT
INCREASED PUMPAGE OF THE SUPPLY WELLS RESULT IN A REDUCED TIME PERIOD FOR REMEDIATION UNDER THIS ALTERNATIVE.
BASED ON THE SIMULATION, A TCE CONCENTRATION OF LESS THAN 5 UG/L COULD BE ACHIEVED AT CW6 AFTER APPROXIMATELY
4.5 YEARS. TCE CONCENTRATIONS AT CW3 RESULTING FROM MIGRATION FROM THE LANDFILL WOULD BE LESS THAN 5 UG/L
AFTER APPROXIMATELY 4 YEARS. WELLS CW3 AND CW6 WOULD CONTINUE TO DRAW IN CONTAMINANTS FROM THE LANDFILL FOR
6 AND 14 YEARS, RESPECTIVELY. PCE CONCENTRATIONS AT PRODUCTION WELL CW3 WOULD BE REDUCED TO LESS THAN 5 UG/L
AFTER APPROXIMATELY 3.3 YEARS AND WELL CW3 WOULD NO LONGER DRAW IN CONTAMINANTS FROM THE WAUSAU CHEMICAL
SOURCES AFTER APPROXIMATELY 5 YEARS.
IT IS NOT ANTICIPATED THAT VOC EMISSIONS FROM THE WATER UTILITY STRIPPING TOWERS WOULD BE HIGHER THAN THOSE
ASSUMED FOR MODELING OF AIR EMISSIONS. NO OFF-GAS CONTROLS ARE PROPOSED FOR THE WATER UTILITY STRIPPING
TOWERS CONSIDERING THAT THEIR OPERATION WOULD PRODUCE EMISSIONS WITHIN THE ACCEPTABLE RISK LEVEL OF (10-6)
AND THEREFORE ARE CONSIDERED REPRESENTATIVE OF BASELINE CONDITIONS. THE SOIL VAPOR EXTRACTION SYSTEMS WOULD
REPRESENT NEW SOURCES. BASED ON PRELIMINARY RISK CALCULATIONS, RISKS ASSOCIATED WITH NEW VOC EMISSIONS IN
THE AREA WOULD NEED TO BE ADDRESSED. VAPOR PHASE CARBON IS THEREFORE INCLUDED FOR OFF-GAS TREATMENT FOR
THESE SYSTEMS.
COSTS FOR ALTERNATIVE 5 ARE SUMMARIZED IN TABLE 15. MAJOR CAPITAL COST ITEMS INCLUDE SOIL GAS EXTRACTION AND
AIR RECHARGE WELLS, HEADER PIPE LINE, BLOWER, MOTOR, CONTROLS AND A SHELTER TO PROTECT EQUIPMENT. MAJOR
OPERATION AND MAINTENANCE COST ITEMS INCLUDE CARBON, ELECTRICITY, MONITORING AND ANALYTICAL LABORATORY COSTS,
ROUTINE SYSTEMS INSPECTION AND MAINTENANCE, AND REPORTING. CAPITAL COSTS ARE ESTIMATED TO BE $252,000.
OPERATION COSTS ARE ESTIMATED TO BE $222,000. PRESENT WORTH COSTS ARE ESTIMATED TO BE $474,000. AN 18-MONTH
OPERATING PERIOD WAS ASSUMED AND COSTS WERE NOT DISCOUNTED.
USE OF THE CITY PRODUCTION WELLS AS PART OF THE REMEDY REQUIRES THAT THE COST OF OPERATING AND MAINTAINING
THE WELLS AND STRIPPING TOWERS BE CONSIDERED PART OF THE COST OF THE REMEDY. COSTS WERE DEVELOPED BASED ON
OPERATING THE 8-FT DIAMETER TOWER AT THE WAUSAU WATER UTILITY. MAJOR ITEMS INCLUDE ENERGY COSTS FOR PUMPING
WELLS AND STRIPPING TOWERS, AND OPERATION AND MAINTENANCE OF STRIPPING TOWERS. IT WAS ASSUMED THAT FOR EACH
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CITY PRODUCTION WELL, THE TIME UNTIL NO MORE CONTAMINANTS ARE DRAWN IN TO A WELL REPRESENTS THE TIME OF
OPERATION. THE ESTIMATED PRESENT WORTH OF THE CITY OPERATING THE TWO CITY WELLS AND TREATING THE WATER IS
$260,000. OPERATING CW6 AND TREATING ITS WATER FOR VOC REMOVAL FOR 14 YEARS ACCOUNTS FOR $180,000. THE
CORRESPONDING COST FOR CW3 FOR A 6-YEAR OPERATING PERIOD IS $80,000. THE ESTIMATED TOTAL PRESENT WORTH COST
OF ALTERNATIVE 5 IS $734,000.
PROBABLE ARARS FOR ALTERNATIVE 5 ARE SUMMARIZED IN TABLE 11. CHEMICAL-SPECIFIC ARARS ADDRESSING DRINKING
WATER, GROUNDWATER AND AIR QUALITY STANDARDS WERE IDENTIFIED FOR ALTERNATIVE 5. THESE INCLUDE DRINKING WATER
MCLS AND NR 140 GROUNDWATER STANDARDS. DRINKING WATER STANDARDS FOR VOCS CAN BE MET AT THE WATER UTILITY
USING VOC STRIPPING TOWER TREATMENT. THIS ALTERNATIVE WOULD MEET THE REQUIREMENTS FOR RESPONSE UNDER CHAPTER
NR 140. MEETING STATE EMISSION LIMITS CAN BE ACHIEVED WITHOUT CONTROLS FOR SPECIFIC ORGANIC COMPOUNDS.
LOCATION-SPECIFIC ARARS INCLUDE REQUIREMENTS RELATED TO ACTIVITIES WITHIN FLOODPLAINS AND WELLHEAD PROTECTION
AREAS. ACTION-SPECIFIG ARARS INCLUDE LANDFILL PROPERTY USE RESTRICTIONS. COMPLIANCE WITH POSSIBLE FUTURE
REQUIREMENTS SHOULD NOT BE A PROBLEM.
IMPLEMENTATION OF THIS ALTERNATIVE IS NOT EXPECTED TO BE A PROBLEM. THE TECHNOLOGY IS READILY AVAILABLE AND
WELL DEMONSTRATED. NO UNUSUAL FEATURES ARE ANTICIPATED WITH IMPLEMENTATION AND OPERATION OF THE SYSTEM.
VIII. SUMMARY OF COMPARATIVE ANALYSIS OF ALTERNATIVES
IN ORDER TO DETERMINE THE MOST APPROPRIATE ALTERNATIVE THAT IS PROTECTIVE OF HUMAN HEALTH AND THE
ENVIRONMENT, ATTAINS ARARS, IS COST-EFFECTIVE, AND UTILIZES PERMANENT SOLUTIONS AND TREATMENT TECHNOLOGIES TO
THE MAXIMUM EXTENT PRACTICABLE, ALTERNATIVES WERE EVALUATED AGAINST EACH OTHER. COMPARISONS WERE BASED ON
THE NINE EVALUATION CRITERIA OUTLINED IN SARA. A SUMMARY OF THE COMPARISON IS PROVIDED IN TABLE 16.
FOLLOWING IS A DISCUSSION OF EACH OF THE CRITERIA AND A SUMMARY OF THE ALTERNATIVES' PERFORMANCE AGAINST EACH
OF THESE.
1. OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT:
EACH OF THE ALTERNATIVES (EXCEPT NO ACTION) WILL ACHIEVE REDUCTION OF RISKS FROM CONTAMINANTS AND PATHWAYS OF
CONCERN IDENTIFIED FOR THE SITE. HOWEVER, THE ALTERNATIVES DIFFER IN THE TIME NEEDED TO PURGE THE AQUIFER OF
CONTAMINANTS, AND THUS TIME TO REDUCE RISKS FROM DRINKING WATER, GROUNDWATER, AND AIR EMISSIONS. ALTERNATIVE
1 REQUIRES THE LONGEST TIME TO ACHIEVE CLEAN-UP. ALTERNATIVE 2 REQUIRES THE NEXT LONGEST PERIOD.
ALTERNATIVES 3 AND 4 REQUIRE SIMILAR PERIODS FOR REMEDIATION OF THE EAST SIDE CONTAMINANT PLUME WHICH IS
EXPECTED TO BE SHORTER THAN PUMP AND TREAT UNDER ALTERNATIVE 2. HOWEVER, AS WITH ALTERNATIVE 2, ALTERNATIVES
3 AND 4 DO NOT PROVIDE ANY REDUCTION IN TIME FOR PURGING OF THE DEEP PLUME MIGRATING UNDER THE RIVER TO CW3.
THIS RESULTS IN A SIGNIFICANTLY LONG TIME PERIOD FOR CONTAMINANTS TO REMAIN IN THE AQUIFER. IN ADDITION,
THERE IS SOME UNCERTAINTY AS TO WHETHER IN-SITU BIORECLAMATION WOULD PERFORM AS PREDICTED FOR THE
CONTAMINANTS PRESENT AT THE SITE. ALTERNATIVE 5 ACHIEVES SOURCE REDUCTION WHICH RESULTS IN A SUBSTANTIAL
REDUCTION IN TIME FOR REMEDIATION OF CONTAMINATION IN THE AQUIFER. INCREASED PUMPAGE OF CITY SUPPLY WELLS AS
CALLED FOR UNDER THIS ALTERNATIVE, FURTHER REDUCES THE TIME FOR REMEDIATION OF THE SITE.
2. COMPLIANCE WITH ARARS:
ALL APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS UNDER FEDERAL AND STATE ENVIRONMENTAL REGULATIONS ARE
MET BY ALTERNATIVES 2, 3, 4 AND 5. ALTERNATIVE 1 (NO ACTION) WOULD NOT COMPLY WITH WISCONSIN NR 140
REQUIREMENTS FOR RESPONSE WHEN GROUNDWATER QUALITY STANDARDS ARE EXCEEDED. THEREFORE, THE NO ACTION
ALTERNATIVE WILL NOT BE INCLUDED IN THE DISCUSSIONS THAT FOLLOW PERTAINING TO EVALUATION OF ALTERNATIVES
AGAINST THE REMAINING CRITERIA.
SUPERFUND MONIES MAY NOT BE ABLE TO BE USED AT THE WAUSAU ENERGY SOURCE AREA IF IT IS DETERMINED THAT
CONTAMINANTS FROM THIS SOURCE ARE STRICTLY DERIVED FROM A PETROLEUM SOURCE. HOWEVER, THE WISCONSIN HAZARDOUS
SUBSTANCES SPILL LAW DOES INCLUDE A PROVISION TO ADDRESS SUCH SPILLS AND WOULD BE PURSUED.
3. LONG-TERM EFFECTIVENESS:
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THE ALTERNATIVES DIFFER IN THE TIME REQUIRED TO ACHIEVE VARIOUS OBJECTIVES, BUT IN THE LONG-TERM, EACH OF THE
ACTION ALTERNATIVES IS EXPECTED TO ACHIEVE COMPLIANCE WITH MCLS AND STATE GROUNDWATER STANDARDS (NR 140) IN
THE AQUIFER. TABLE 16 LISTS THE TIME PERIOD REQUIREMENT FOR EACH OF THE ALTERNATIVES.
4. REDUCTION OF TOXICITY, MOBILITY OR VOLUME:
ALTERNATIVES 3 AND 4 PROVIDE TOXICITY REDUCTION AS A RESULT OF CONTAMINANT DEGRADATION. VOLUME AND TOXICITY
REDUCTIONS ARE PROVIDED BY ALTERNATIVES 2, 3 AND 5 AS A RESULT OF CONTAMINANT ADSORPTION ON VAPOR PHASE
CARBON AND SUBSEQUENT DESTRUCTION DURING THERMAL REGENERATION OF THE CARBON.
5. SHORT-TERM EFFECTIVENESS:
THE SHORT-TERM RISKS ASSOCIATED WITH IMPLEMENTATION ARE NOT EXPECTED TO BE A PROBLEM FOR ANY OF THE
ALTERNATIVES. ALL OF THE ALTERNATIVES (INCLUDING THE PHASE I REMEDY) WILL RESULT IN CONTAMINATED MATERIAL
BEING BROUGHT TO THE SURFACE, HOWEVER NO APPRECIABLE RISKS TO RESIDENTS ARE EXPECTED, AND WORKERS CAN USE
CONVENTIONAL PERSONNEL PROTECTIVE GEAR.
SHORT-TERM RISKS ASSOCIATED WITH OPERATION OF THE ALTERNATIVES VARY. CARBON TREATMENT OF OFF-GASES GENERATED
BY STRIPPING OF VOCS IS PLANNED FOR ALTERNATIVES 2,5, AND THE PUMP AND TREAT PORTION OF ALTERNATIVE 3.
ALTERNATIVE 4 AND THE BIORECLAMATION PORTION OF ALTERNATIVE 3 DO HAVE POTENTIAL RISKS ASSOCIATED WITH THE
ADDITIVES NECESSARY FOR CONTAMINANT BREAKDOWN AND THE TRANSFORMATION PRODUCTS FROM THE PROCESS. RISKS FROM
THESE ALTERNATIVES WOULD RESULT IF THE CONTAMINANTS WERE NOT BROKEN DOWN COMPLETELY BEFORE REACHING CW3, OR
IF ADDITIVES FROM THE PROCESS WERE TO REACH CW3.
THE ALTERNATIVES DIFFER IN THE TIME NEEDED TO PURGE THE AQUIFER OF CONTAMINANTS. ALTERNATIVE 2 REQUIRES THE
LONGEST TIME TO ACHIEVE AQUIFER PURGING. THIS IS BECAUSE PUMPING OF EXTRACTION WELLS AT WAUSAU CHEMICAL IN
CONJUNCTION WITH CW3 WOULD CREATE A GROUNDWATER DIVIDE THAT WOULD ACTUALLY CAUSE CONTAMINANTS TO BE HELD UP
LONGER IN THE AQUIFER. IN ADDITION, THIS ALTERNATIVE WOULD NOT REDUCE THE TIME FRAME DURING WHICH
CONTAMINANTS WOULD CONTINUE TO IMPACT CW6 ON THE WEST SIDE OF THE RIVER. ALTERNATIVES 3 AND 4 REQUIRE
SIMILAR PERIODS FOR REMEDIATION OF THE EAST SIDE CONTAMINANT PLUME WHICH IS EXPECTED TO BE SHORTER THAN PUMP
AND TREAT UNDER ALTERNATIVE 2. HOWEVER, AS WITH ALTERNATIVE 2, THESE ALTERNATIVES DO NOT PROVIDE ANY
REDUCTION IN TIME FOR PURGING OF THE DEEP TCE PLUME MIGRATING UNDER THE RIVER TO CW3. ALTERNATIVE 5 RESULTS
IN A SUBSTANTIAL REDUCTION IN TIME FOR REMEDIATION OF CONTAMINATION IN THE AQUIFER BECAUSE IT ADDRESSES THE
SOURCE AREAS ON BOTH SIDES OF THE RIVER. ADDED CONTROLS ON PUMPING RATES OF CITY SUPPLY WELLS FURTHER
REDUCES THE TIME FOR REMEDIATION UNDER THIS ALTERNATIVE.
6. IMPLEMENTABILITY:
TECHNOLOGIES USED FOR ALTERNATIVES 2 AND 5, AND PART OF 3, ARE CONVENTIONAL AND WELL DEMONSTRATED.
BIORECLAMATION AS PROPOSED FOR ALTERNATIVE 4 AND PART OF ALTERNATIVE 3 IS NOT CONVENTIONAL OR WELL
DEMONSTRATED FOR THE TYPES OF CHEMICALS FOUND AT THE SITE. IN ADDITION, Us EPA'S OFFICE OF RESEARCH AND
DEVELOPMENT (ORD) HAS REVIEWED THE POTENTIAL FOR IN-SITU BIORECLAMATION AND HAS EXPRESSEDCONCERN OVER THE
UNCERTAINTIES REGARDING WHETHER THIS TECHNOLOGY WOULD WORK FOR THE CONTAMINANTS FOUND AT THE SITE.
IMPLEMENTATION WOULD REQUIRE FAIRLY EXTENSIVE LABORATORY AND FIELD TESTING PRIOR TO START-UP. IT IS ESTIMATED
THAT APPROXIMATELY TWO YEARS WOULD BE REQUIRED PRIOR TO FULL SCALE OPERATION OF A BIORECLAMATION SYSTEM AT
THE SITE.
ADMINISTRATIVELY, ALTERNATIVE 5 WOULD REQUIRE THE LEAST AMOUNT OF COORDINATION. ALTERNATIVES 2, AND THE
ABOVE GROUND PORTION OF 3 REQUIRE ADDITIONAL COORDINATION BECAUSE OF TREATMENT AND DISCHARGE SYSTEM.
ALTERNATIVE 4 AND THE IN-SITU PORTION OF 3 WOULD BE ADMINISTRATIVELY DIFFICULT BECAUSE THE TECHNOLOGY IS
RELATIVELY UNKNOWN, AND REQUIRES REINJECTION OF WATER BACK INTO THE GROUND.
THERE ARE NO DIFFICULTIES ANTICIPATED IN OBTAINING MATERIALS FOR ANY OF THE ALTERNATIVES. MATERIALS ARE
AVAILABLE AND CONSIDERED CONVENTIONAL AND READILY AVAILABLE.
7. COST:
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COMPARISON OF PRESENT WORTH COSTS FOR THE ALTERNATIVES INDICATES THAT ALTERNATIVE 5 IS THE LEAST COSTLY AT
$738,000. THIS IS DUE TO THE SHORTER OPERATION TIME OF THE SOURCE CONTROL ACTION AND THE REDUCED O&M COSTS
ASSOCIATED WITH THE CITY AIR STRIPPERS DUE TO THE REDUCED TIME REQUIRED FOR THEIR USE. ALTERNATIVE 2 HAS THE
NEXT LOWEST PRESENT WORTH COST AT $1,330,000. ALTERNATIVE 4 IS SOMEWHAT HIGHER AT $1,380,000 AND THE PRESENT
WORTH COST FOR ALTERNATIVE 3 IS HIGHEST AT $1,710,000 DUE TO THE COMBINATION OF SYSTEMS USED. ALTERNATIVE 1
HAS NO ASSOCIATED COSTS.
8. STATE ACCEPTANCE:
THE STATE HAD EXPRESSED INTEREST IN A BIORECLAMATION ALTERNATIVE IF ONE SHOWED PROMISE FOR THE SITE.
HOWEVER, BECAUSE OF THE NEED FOR EXTENSIVE LABORATORY AND FIELD PILOT STUDIES, THE STATE HAS AGREED THAT A
BIORECLAMATION ALTERNATIVE SHOULD NOT BE PURSUED FOR THE SITE. THE STATE SUPPORTS ALTERNATIVE 5 DUE TO ITS
ABILITY TO REDUCE AQUIFER PURGE TIMES AT A LOW COST.
9. COMMUNITY ACCEPTANCE:
THE CITY OF WAUSAU, MARATHON ELECTRIC, AND WAUSAU CHEMICAL, ALL OF WHICH ARE PRPS, HAVE EXPRESSED A
PREFERENCE FOR ALTERNATIVE FIVE. THE COMMUNITY IN WAUSAU HAS NOT EXPRESSED A PREFERENCE FOR ANY ALTERNATIVE.
SPECIFIC COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD AND AT THE PUBLIC MEETING FOR THE PROPOSED PLAN
ARE ADDRESSED IN THE RESPONSIVENESS SUMMARY INCLUDED WITH THIS DOCUMENT.
SUMMARY OF COMPARISON
UNDER ALTERNATIVE 1 (NO ACTION), CONTAMINANTS WOULD BE PURGED ONLY THROUGH PUMPING OF THE SUPPLY WELLS AND
THE WEST SIDE EXTRACTION WELL. NOTHING WOULD BE DONE TO REDUCE CONTAMINANT LOADING TO THE AQUIFER FROM SOURCE
AREAS NOR TO EXPEDITE REMOVAL OF CONTAMINANTS IN THE EAST WELL FIELD. GIVEN THE NATURE AND LOCATION OF THE
SITE, THIS ALTERNATIVE IS NOT CONSISTENT WITH THE OBJECTIVES FOR REMEDIAL ACTION AT THE SITE AND IS THEREFORE
NOT CONSIDERED A VIABLE OPTION FOR THE SITE. IN ADDITION, WISCONSIN GROUNDWATER STANDARDS UNDER NR 140 WOULD
NOT BE MET UNDER THIS ALTERNATIVE. NR 140 HAS BEEN DETERMINED TO BE AN ARAR FOR THE SITE.
ALTHOUGH ALL OF THE OTHER ALTERNATIVES WILL ACHIEVE AQUIFER PURGING IN THE LONG-TERM, THERE ARE SIGNIFICANT
DIFFERENCES IN THE TIME TO PURGE THE GROUNDWATER. ALTERNATIVES 2, 3, AND 4 ARE GROUNDWATER REMEDIATION
ALTERNATIVES THAT DO NOT ADDRESS REMEDIATION OF SOURCE AREAS. IN ADDITION, THEY DO NOT PROVIDE ANY REDUCTION
IN THE TIME TO REMEDIATE THE DEEP PLUME ORIGINATING FROM THE LANDFILL. THIS RESULTS IN A SIGNIFICANT TIME
PERIOD TO ACHIEVE THE RESPONSE OBJECTIVES. IN ADDITION, THE ACTUAL TIME FRAME FOR AQUIFER PURGING UNDER THE
BIOREMEDIATION ALTERNATIVES CANNOT BE DETERMINED, SO AN ESTIMATE IS BASED ON GROUNDWATER FLOW. ALTERNATIVE 5,
SOURCE CONTROL, REQUIRES THE SHORTEST TIME PERIOD FOR REMEDIATION OF THE SITE BECAUSE IT ELIMINATES THE
CONTINUED ADDITION OF CONTAMINANTS TO THE GROUNDWATER AND PROVIDES FOR THE REMOVAL OF REMAINING CONTAMINANTS
IN GROUNDWATER THROUGH PUMPING OF CW3 AND CW6. ALTERNATIVE 5 ALSO PROVIDES FOR A REDUCTION IN TIME TO PURGE
THE DEEP WEST SIDE PLUME BY REMOVING THE SOURCE AND SPECIFYING PUMPING RATES FOR THE CITY'S SUPPLY WELLS CW3
AND CW6.
ALL OF THE ALTERNATIVES (OTHER THAN NO ACTION) PROVIDE A REDUCTION IN TOXICITY OF CONTAMINANTS. ALTERNATIVES
2, 5 AND THE PUMP AND TREAT PORTION OF 3 PROVIDE A REDUCTION IN VOLUME AS WELL. ALTERNATIVES 2 AND 5 USE
PROVEN TECHNOLOGIES THAT CAN EASILY BE IMPLEMENTED AND HAVE A LOW POTENTIAL FOR FAILURE, AND THE PROPOSED
ACTIONS WILL HAVE NO PROBLEM COMPLYING WITH FEDERAL AND STATE ARARS. ALTERNATIVES 3 AND 4 USE A TECHNOLOGY
THAT MAY NOT BE COMPLETELY EFFECTIVE ON THE CONTAMINANTS PRESENT AT THE SITE. IN ADDITION, SOME OF THE
REQUIRED ADDITIVES NEEDED TO ENHANCE BIODEGRADATION, COULD EXCEED THE STATE'S NR 140 GROUNDWATER STANDARDS
FOR THOSE SUBSTANCES.
COSTS AND IMPLEMENTATION TIMES FOR ALTERNATIVES VARY AS WELL. ALTERNATIVE 5, SOURCE CONTROL, IS THE LEAST
COSTLY AND REQUIRES THE SHORTEST TIME PERIOD TO IMPLEMENT AND COMPLETE THE REMEDIAL ACTION. ALTERNATIVE 2 HAS
THE NEXT LOWEST COST AND REQUIRES A SIMILAR IMPLEMENTATION PERIOD. ALTERNATIVES 3 AND 4 HAVE THE HIGHEST
COSTS ASSOCIATED WITH THEM DUE TO THE BIORECLAMATION TECHNOLOGY PROPOSED. THESE ALTERNATIVES ALSO REQUIRE THE
LONGEST IMPLEMENTATION TIME. A PERIOD OF 2 YEARS TO BEGIN THE PROCESS WILL BE REQUIRED DUE TO THE NEED FOR
EXTENSIVE TESTING PRIOR TO START UP.
-------
#SR
IX. SEIiECTED REMEDY AND STATUTORY DETERMINATIONS
SECTION 121 OF SARA REQUIRED THAT ALL REMEDIES FOR SUPERFUND SITES BE PROTECTIVE OF HUMAN HEALTH AND THE
ENVIRONMENT, COMPLY WITH ARARS, BE COST-EFFECTIVE, AND UTILIZE PERMANENT SOLUTIONS AND ALTERNATE TREATMENT
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE. ALTERNATIVE 5 IS BELIEVED TO PROVIDE THE BEST BALANCE OF
TRADE-OFFS AMONG ALTERNATIVES WITH RESPECT TO THE CRITERIA USED TO EVALUATE REMEDIES. BASED ON THE
EVALUATION OF THE ALTERNATIVES, Us EPA AND THE STATE OF WISCONSIN BELIEVE THAT ALTERNATIVE 5 WOULD BE
PROTECTIVE, ATTAIN ARARS, BE COST-EFFECTIVE, AND WILL UTILIZE PERMANENT SOLUTIONS AND ALTERNATE TREATMENT
TECHNOLOGIES OR RESOURCE RECOVERY TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE.
THE SELECTED REMEDY ENTAILS:
* INSTALLATION OF SOIL VAPOR EXTRACTION (SVE) SYSTEMS TO REMOVE
VOCS IN SOILS AT EACH OF THE THREE IDENTIFIED SOURCE AREAS;
* TREATMENT OF OFF-GASES FROM THE SVE OPERATION USING VAPOR
PHASE CARBON UNITS WHICH WILL BE REGENERATED AT AN OFF-SITE
RCRA APPROVED FACILITY; AND
* GROUNDWATER REMEDIATION UTILIZING SPECIFIED PUMPAGE RATES OF
THE MUNICIPAL SUPPLY WELLS IN ORDER TO EXPEDITE REMOVAL OF THE
GROUNDWATER CONTAMINANT PLUMES AFFECTING THESE WELLS.
* TREATMENT OF GROUNDWATER UTILIZING EXISTING CITY AIR STRIPPERS
THE RESPONSE OBJECTIVES FOR THE FINAL REMEDY ARE TO ELIMINATE RISKS TO GROUNDWATER BY REDUCING THE SOURCE OF
CONTAMINANTS IN SOURCE AREAS' SOILS, AND TO MINIMIZE VOC EMISSIONS TO AIR FROM THE EXISTING AND PROPOSED
TREATMENT PROCESSES. THE PERFORMANCE STANDARDS FOR THE SVE IN SOURCE SOILS WILL BE DETERMINED USING A
MASS-FLUX GROUNDWATER MODEL TO DETERMINE WHAT CLEANUP LEVELS ARE NEEDED IN SOILS TO ACHIEVE CLEANUP OF THE
AQUIFER. THESE CLEANUP LEVELS WILL BE BASED ON THE REQUIREMENT TO ATTAIN WISCONSIN NR 140 GROUNDWATER
STANDARDS FOR PCE, 1.0 UG/L, AND TCE, 1.8 UG/L AT THE SOURCE BOUNDARY. ATTAINMENT OF CLEANUP LEVELS WILL BE
CONFIRMED THROUGH SAMPLE ANALYSIS OF GROUNDWATER AT THE BOUNDARY OF THE SOURCE AREAS.
THE FINAL REMEDY INCORPORATES THE INTERIM REMEDY SUCH THAT THE WEST SIDE EXTRACTION SYSTEM IS CONSIDERED PART
OF THE OVERALL SITE REMEDIATION. IT IS EXPECTED TO ADDRESS THE TCE CONTAMINATION ORIGINATING FROM THE FORMER
CITY LANDFILL/MARATHON ELECTRIC SOURCE AREA WHICH MIGRATES TO BOTH CW6 AND CW3. IT ALSO INCLUDES A PROVISION
FOR AN ADDITIONAL EXTRACTION WELL IF REQUIRED TO OBTAIN THE DESIRED PERFORMANCE OBJECTIVES. THE INTERIM ROD
DID NOT SPECIFY A TIME PERIOD FOR OPERATION OF THE WEST SIDE EXTRACTION SYSTEM BECAUSE CONTAMINANT TRANSPORT
MODELING HAD NOT BEEN COMPLETED AT THE TIME. IT IS NOW ANTICIPATED THAT THIS SYSTEM WILL BE REQUIRED TO
OPERATE FOR APPROXIMATELY 14 YEARS; UNTIL LEVELS OF TCE ARE NOT DETECTED ABOVE THE WISCONSIN NR 140 STANDARD
OF 1.8 UG/L AT SPECIFIED POINTS OF COMPLIANCE.
HE COSTS ESTIMATED FOR ALTERNATIVE 5 DO NOT INCLUDE COSTS FOR OPERATING THE INTERIM REMEDY EXTRACTION WELL.
FIVE YEARS OF OPERATION AND MAINTENANCE COSTS FOR THE INTERIM REMEDY WERE ESTIMATED IN THE INTERIM ROD. IT
IS NOW ESTIMATED THAT THE SYSTEM WILL BE REQUIRED TO OPERATE FOR APPROXIMATELY 14 YEARS. THIS WILL REQUIRE
AN ADDITIONAL 9 YEARS OF O&M AND WILL RESULT IN ADDITIONAL COSTS FOR THAT SYSTEM. ESTIMATED COSTS FOR O&M OF
THE INTERIM SYSTEM WERE ESTIMATED TO BE $140,000 PER YEAR. HOWEVER IT IS EXPECTED THAT ACTUAL O&M COSTS FOR
THE SYSTEM WILL BE SOMEWHAT LESS DUE TO OVERLAP OF MONITORING REQUIREMENTS FOR THE REMAINING PORTIONS OF THE
SITE.
THE FINAL REMEDY ALSO WILL REQUIRE THAT EXISTING GROUNDWATER EXTRACTION SYSTEMS CURRENTLY OPERATING IN THE
EAST WELL FIELD, OTHER THAN CITY SUPPLY WELL CW3, CEASE OPERATION ONCE THE SVE SYSTEM IS INSTALLED. THIS IS
NECESSARY IN ORDER TO OBTAIN THE DESIRED RESULT OF PURGING CONTAMINANTS FROM THE AQUIFER UTILIZING CW3.
GROUNDWATER MODELING PERFORMED DURING THE FS INDICATED THAT COMPETING EXTRACTION SYSTEMS COULD CAUSE
CONTAMINANTS TO GET TRAPPED AT THE GROUNDWATER DIVIDE CREATED BY MULTIPLE PUMPING SYSTEMS, AND REQUIRE LONGER
PURGE TIME TO REMEDIATE THE AQUIFER.
-------
AS STATED ABOVE, THE REMEDY IS CONSIDERED THE MOST COST-EFFECTIVE REMEDIAL ACTION. IT COMPLIES WITH FEDERAL
AND STATE ARARS. IT IS PROTECTIVE OF HUMAN HEALTH AND THE ENVIRONMENT BY REDUCING THE TIME PERIOD DURING
WHICH WATER CONSUMERS ARE EXPOSED TO TRACE LEVELS OF CONTAMINANTS IN DRINKING WATER, BY ELIMINATING FUTURE
POTENTIAL RISK TO PRIVATE WELL USERS, AND BY PREVENTING INCREASED VOC EMISSIONS TO BE RELEASED TO THE
ATMOSPHERE. REQUIREMENTS OF SECTION 121(B)(1)(A-G) WHICH HAVE BEEN DETERMINED TO BE APPLICABLE TO THIS
OPERATION ARE DISCUSSED BELOW.
1. PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
BASED ON THE RISK ASSESSMENT DEVELOPED FOR THE SITE, LONG-TERM EXPOSURE TO LOW LEVELS OF VOCS IN DRINKING
WATER, POTENTIAL EXPOSURE THROUGH THE USE OF PRIVATE WELLS, AND EXPOSURE TO AIR EMISSIONS FROM EXISTING VOC
TREATMENT SYSTEMS ARE THE IDENTIFIED RISKS ASSOCIATED WITH THE SITE. IMPLEMENTATION OF SVE SYSTEMS AT THE
SOURCE AREAS AND TREATMENT OF OFF-GASES, AS CALLED FOR UNDER ALTERNATIVE 5, PROVIDES PROTECTION TO HUMAN
HEALTH AND THE ENVIRONMENT THROUGH VOLATILIZATION OF VOCS FROM CONTAMINATED SOILS, AND EXPEDITED REMOVAL OF
CONTAMINANTS FROM GROUNDWATER BY INCREASED PUMPAGE OF MUNICIPAL WELLS.
VOLATILIZATION OF VOC-CONTAMINATED SOILS WILL ELIMINATE THE SOURCE OF CONTINUED LOADING OF VOCS TO THE
AQUIFER; THUS REDUCING THE TIME DURING WHICH RESIDENTS ARE EXPOSED TO TRACE LEVELS OF VOCS. IMPLEMENTATION
OF ALTERNATIVE 5 WILL NOT POSE ANY UNACCEPTABLE SHORT-TERM RISKS OR CROSS-MEDIA IMPACTS TO THE SITE, THE
WORKERS, OR THE COMMUNITY. NO ENVIRONMENTAL IMPACTS HAVE BEEN IDENTIFIED FOR THE SITE. THIS IS LARGELY DUE
TO THE FACT THAT IMPACTS FROM THE SITE HAVE BEEN TO GROUNDWATER, AND SOILS IN INDUSTRIAL AREAS.
2. ATTAINMENT OF APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS OF ENVIRONMENTAL LAWS
ALTERNATIVE 5 WILL BE DESIGNED TO MEET ALL APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARS) OF
FEDERAL AND MORE STRINGENT STATE ENVIRONMENTAL LAWS. TABLES 7-11 LIST THE ARARS THAT APPLY TO EACH OF THE
ACTION ALTERNATIVES AND THE FOLLOWING DISCUSSION PROVIDES THE DETAILS OF THE ARARS THAT WILL BE MET BY
ALTERNATIVE 5. THE LAND BAN REQUIREMENTS OF RCRA DO NOT APPLY TO THIS REMEDIAL ACTION.
A. FEDERAL: SAFE DRINKING WATER ACT (SDWA) / STATE CHAPTER NR
109 WISCONSIN ADMINISTRATIVE CODE (WAG)
THE SDWA AND CORRESPONDING STATE STANDARDS SPECIFIES MAXIMUM CONTAMINANT LEVELS (MCLS) FOR DRINKING WATER AT
PUBLIC WATER SUPPLIES. SINCE TCE IS REGULATED UNDER THE SDWA MCLS, REQUIREMENTS FOR ACHIEVING MCLS ARE
RELEVANT AND APPROPRIATE FOR THIS REMEDIAL ACTION. PCE IS UNDER CONSIDERATION FOR A PROPOSED MCL OF 5 UG/L
IN THE NEAR FUTURE. THEREFORE, THE LIKELY PROPOSED MCL FOR PCE IS A TBC (TO BE CONSIDERED) FOR THIS REMEDIAL
ACTION.
B. STATE: CHAPTER NR 140 WAG
WISCONSIN GROUNDWATER PROTECTION ADMINISTRATIVE RULE, CHAPTER NR 140 WAG, REGULATES PUBLIC HEALTH GROUNDWATER
QUALITY STANDARDS FOR THE STATE OF WISCONSIN. THE ENFORCEABLE GROUNDWATER QUALITY STANDARD FOR TCE IS 1.8
UG/L. GROUNDWATER QUALITY STANDARDS AS FOUND IN NR 140 WAG ARE ARARS FOR THIS REMEDIAL ACTION.
C. FEDERAL: CLEAN AIR ACT (CAA)
THE CAA IDENTIFIES AND REGULATES THE RELEASE OF POLLUTANTS TO AIR. SECTION 109 OF THE CAA IDENTIFIES THOSE
POLLUTANTS FOR WHICH AMBIENT AIR QUALITY STANDARDS (AAQS) HAVE BEEN ESTABLISHED. SECTION 112 OUTLINES
CRITERIA FOR POLLUTANTS FOR WHICH THERE ARE NO APPLICABLE AAQS. EMISSIONS FROM EXISTING AND PROPOSED
TREATMENT SYSTEMS ARE NOT EXPECTED TO EXCEED THE AAQSS FOR ANY OF THE COMPOUNDS PRESENT IN GROUNDWATER.
D. STATE: CHAPTER NR 445 WAG
WISCONSIN CHAPTER NR 445 ESTABLISHES HOURLY OR ANNUAL EMISSION RATE LIMITS FOR SPECIFIC CONTAMINANTS.
EMISSIONS RATES ON THE ORDER OF 1 LB/DAY FOR INDIVIDUAL SYSTEMS ARE ESTIMATED AND WOULD BE EXPECTED TO MEET
THE LIMITS.
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3. COST-EFFECTIVENESS
ALTERNATIVE 5 AFFORDS A HIGH DEGREE OF EFFECTIVENESS BY PROVIDING PROTECTION FROM CHRONIC LOW LEVEL EXPOSURE
OF TCE FOR PRODUCTION WELLS CW3 AND CW6, PROVIDING PROTECTION FROM POTENTIAL EXPOSURE TO FUTURE PRIVATE
WELL USERS, AND PREVENTING FURTHER DISCHARGE OF VOC EMISSIONS. ALTERNATIVE 5 IS THE LEAST COSTLY ALTERNATIVE
THAT IS PROTECTIVE OF HUMAN HEALTH AND THE ENVIRONMENT. THEREFORE, ALTERNATIVE 5 IS CONSIDERED TO BE THE
MOST COST-EFFECTIVE ALTERNATIVE THAT IS PROTECTIVE.
4. UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT TECHNOLOGIES OR RESOURCE RECOVERY
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE
US EPA AND THE STATE OF WISCONSIN BELIEVE THE SELECTED REMEDY REPRESENTS THE MAXIMUM EXTENT TO WHICH
PERMANENT SOLUTIONS AND TREATMENT TECHNOLOGIES CAN BE UTILIZED IN A COST-EFFECTIVE MANNER FOR THE FINAL
REMEDY AT THE WAUSAU SITE. OF THE ALTERNATIVES THAT ARE PROTECTIVE OF HUMAN HEALTH AND THE ENVIRONMENT AND
COMPLY WITH ARARS, Us EPA AND THE STATE HAVE DETERMINED THAT THE SELECTED REMEDY PROVIDES THE BEST BALANCE
OF TRADEOFFS IN TERMS OF LONG-TERM EFFECTIVENESS AND PERMANENCE, REDUCTION IN TOXICITY, MOBILITY OR VOLUME
ACHIEVED THROUGH TREATMENT, SHORT-TERM EFFECTIVENESS, IMPLEMENTABILITY, COST, ALSO CONSIDERING THE STATUTORY
PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT AND CONSIDERING STATE AND COMMUNITY ACCEPTANCE.
ALTHOUGH ALL OF THE ALTERNATIVES THAT ARE PROTECTIVE AND COMPLY WITH ARARS WILL ACHIEVE REDUCTION OF RISKS,
THERE ARE SIGNIFICANT DIFFERENCES IN THE TIME REQUIRED TO ACHIEVE THIS GOAL. ALTERNATIVES 2, 3, AND 4 ARE
GROUNDWATER REMEDIATION ALTERNATIVES THAT DO NOT ADDRESS SOURCE AREAS. THIS RESULTS IN CONTAMINATION FROM
SOURCE AREA SOILS LOADING TO THE AQUIFER FOR SEVERAL ADDITIONAL YEARS. IN ADDITION, NONE OF THESE
ALTERNATIVES PROVIDE ANY REDUCTION IN TIME TO REMEDIATE THE DEEP TCE PLUMES ORIGINATING FROM THE FORMER
LANDFILL SOURCE AREA. THIS ALSO RESULTS IN A SIGNIFICANT TIME PERIOD TO ACHIEVE REDUCTION OF RISKS.
ALTERNATIVE 5 REQUIRES THE SHORTEST TIME PERIOD FOR REMEDIATION OF THE SITE BECAUSE IT ELIMINATES THE
CONTINUED LOADING OF CONTAMINANTS TO THE GROUNDWATER, AND IT PROVIDES FOR REDUCTION IN TIME TO PURGE THE DEEP
TCE PLUMES BY REMOVING THE SOURCE AND INCREASING REMOVAL RATES OF CONTAMINANTS AT THE MUNICIPAL SUPPLY WELLS.
THE SELECTION OF A TREATMENT TECHNOLOGY FOR REMEDIATION OF CONTAMINATED SOILS IS CONSISTENT WITH THE
SUPERFUND PROGRAM POLICY THAT THE HIGHLY TOXIC AND MOBILE WASTES ARE A PRIORITY FOR TREATMENT AND TO ENSURE
PERMANENCE AND LONG-TERM EFFECTIVENESS OF THE REMEDY. UNDER THE SELECTED REMEDY, TREATMENT OF GROUNDWATER
WILL NOT PROVIDE A REDUCTION OF TOXICITY, MOBILITY, OR VOLUME (TMV). HOWEVER, IT WILL REDUCE CONTAMINANT
LEVELS IN GROUNDWATER AND THUS REDUCE THE RISKS ASSOCIATED WITH INGESTION OF GROUNDWATER, WHICH HAS BEEN
DETERMINED TO BE A GREATER RISK THAN INHALATION OF AIR EMISSIONS. WHILE OTHER ALTERNATIVES EVALUATED PROVIDED
TREATMENT TO ACHIEVE TMV REDUCTIONS IN GROUNDWATER, THESE ALTERNATIVES HAD OTHER DIFFICULTIES. ALTERNATIVE 2
REQUIRED ALMOST TWICE AS LONG TO PURGE CONTAMINANTS. ALTERNATIVES 3 AND 4 PROPOSE A TECHNOLOGY THAT HAS
NOT BEEN SHOWN TO WORK ON CONTAMINANTS PRESENT IN GROUNDWATER AT THE SITE AND THUS WOULD REQUIRE EXTENSIVE
TESTING THAT WOULD DELAY FULL SCALE OPERATION OF THE SYSTEM FOR AN ESTIMATED TWO YEARS. BASED ON THESE
FACTORS, IT WAS DETERMINED THAT ALTERNATIVE 5 WOULD PROVIDE THE SHORTEST TIME PERIOD DURING WHICH RECEPTORS
WOULD BE EXPOSED TO CONTAMINANTS IN DRINKING WATER. IN ADDITION, BASED ON AIR MODELING, RELEASE OF EMISSIONS
FROM THE MUNICIPAL AIR STRIPPERS DO NOT CONTRIBUTE A GREATER THAN 1 X (10-6) RISK LEVEL TO RECEPTORS.
SINCE TREATMENT OF GROUNDWATER WILL NOT ACHIEVE A REDUCTION IN TOXICITY, MOBILITY OR VOLUME, THE MAJOR
TRADE-OFFS THAT PROVIDE THE BASIS FOR THIS SELECTION DECISION ARE LONG-TERM EFFECTIVENESS, SHORT-TERM
EFFECTIVENESS, IMPLEMENTABILITY, AND COST. THE SELECTED REMEDY CAN BE IMPLEMENTED AND COMPLETED MORE QUICKLY
WITH LESS DIFFICULTY AND AT LESS COST THAN GROUNDWATER TREATMENT ALTERNATIVES, THUS REDUCING THE EXPOSURE
TIME FOR PATHWAYS OF CONCERN. ALTERNATIVE 5 IS THEREFORE CONSIDERED TO BE THE MOST APPROPRIATE SOLUTION TO
CONTAMINATION AT THE SITE BECAUSE IT PROVIDES THE BEST TRADE-OFFS WITH RESPECT TO THE NINE CRITERIA AND
REPRESENTS THE MAXIMUM EXTENT TO WHICH PERMANENT SOLUTIONS AND TREATMENT ARE PRACTICABLE.
5. PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
BY TREATING THE VOC-CONTAMINATED SOILS USING SVE WITH CARBON ABSORPTION OF OFF-GASES WITH REGENERATION OF THE
CARBON, THE SELECTED REMEDY SATISFIES THE STATUTORY PREFERENCE FOR REMEDIES THAT EMPLOY TREATMENT OF THE
PRINCIPAL THREAT WHICH PERMANENTLY AND SIGNIFICANTLY REDUCES TOXICITY, MOBILITY, OR VOLUME OF HAZARDOUS
SUBSTANCES AS A PRINCIPAL ELEMENT. TREATMENT OF GROUNDWATER TO REDUCE TOXICITY, MOBILITY, OR VOLUME WOULD
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ALSO SEEM TO BE DESIRABLE TO SATISFY THE STATUTORY PREFERENCE. HOWEVER, TREATMENT OF GROUNDWATER TO
PERMANENTLY AND SIGNIFICANTLY REDUCE TOXICITY, MOBILITY, OR VOLUME OF CONTAMINANTS WAS NOT FOUND TO BE
PRACTICABLE OR COST-EFFECTIVE FOR REMEDIATION OF THE SITE.
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#RS
RESPONSIVENESS SUMMARY: WAUSAU GROUNDWATER CONTAMINATION SITE
WAUSAU, WISCONSIN
PURPOSE
THIS RESPONSIVENESS SUMMARY IS DEVELOPED TO DOCUMENT COMMUNITY INVOLVEMENT AND CONCERNS DURING THE
DEVELOPMENT OF THE FEASIBILITY STUDY (FS) FOR THE WAUSAU GROUNDWATER CONTAMINATION SITE, WAUSAU, WISCONSIN.
COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD WERE CONSIDERED IN THE SELECTION OF THE REMEDIAL ACTION
FOR THE SITE. THE RESPONSIVENESS SUMMARY SERVES TWO PURPOSES: IT PROVIDES Us EPA WITH INFORMATION ABOUT
COMMUNITY PREFERENCES AND CONCERNS REGARDING THE REMEDIAL ALTERNATIVES, AND IT SHOWS MEMBERS OF THE COMMUNITY
HOW THEIR COMMENTS WERE INCORPORATED INTO THE DECISION-MAKING PROCESS.
THIS DOCUMENT SUMMARIES THE ORAL COMMENTS RECEIVED AT THE PUBLIC MEETING HELD AUGUST 22, 1989, AND ONE
WRITTEN COMMENT RECEIVED DURING THE PUBLIC COMMENT PERIOD OF AUGUST 14 TO SEPTEMBER 12, 1989.
OVERVIEW
THE PREFERRED ALTERNATIVE FOR THE WAUSAU GROUNDWATER CONTAMINATION (WAUSAU) SITE WAS ANNOUNCED TO THE PUBLIC
JUST PRIOR TO THE BEGINNING OF THE PUBLIC COMMENT PERIOD. THE PREFERRED ALTERNATIVE INCLUDES:
* INSTALLATION OF SOIL VAPOR EXTRACTION (SVE) SYSTEMS TO REMOVE
VOCS IN SOILS AT EACH OF THE THREE IDENTIFIED SOURCE AREAS;
* TREATMENT OF OFF-GASES FROM THE SVE OPERATION USING VAPOR
PHASE CARBON UNITS WHICH WILL BE REGENERATED AT AN OFF-SITE
RCRA APPROVED FACILITY; AND
* GROUNDWATER REMEDIATION UTILIZING SPECIFIED PUMPAGE RATES OF
THE MUNICIPAL SUPPLY WELLS IN ORDER TO EXPEDITE REMOVAL OF THE
GROUNDWATER CONTAMINANT PLUMES AFFECTING THESE WELLS.
* TREATMENT OF GROUNDWATER UTILIZING EXISTING CITY AIR STRIPPERS
JUDGING FROM THE COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD, ALL PARTIES SUPPORT THE SELECTED REMEDY.
HOWEVER, CONCERN HAS BEEN EXPRESSED OVER THE AMOUNT OF MONEY SPENT TO DATE AT THE SITE BY ALL PARTIES
INVOLVED.
SUMMARY OF PUBLIC COMMENTS AND AGENCY RESPONSES
THE PUBLIC COMMENT PERIOD WAS HELD FROM AUGUST 14 TO SEPTEMBER 12, 1989 TO RECEIVE COMMENTS CONCERNING THE
DRAFT FEASIBILITY STUDY (FS). BECAUSE OF THE SIMILARITIES, INDIVIDUAL COMMENTS HAVE BEEN SUMMARIZED AND
GROUPED WHERE APPROPRIATE.
A. COMMENT: THE MAYOR OF WAUSAU, THE WAUSAU CITY COUNCIL PRESIDENT, WAUSAU CHEMICAL CORPORATION, AND MARATHON
ELECTRIC CORPORATION ALL EXPRESSED SUPPORT FOR THE AGENCY'S SELECTED ALTERNATIVE. HOWEVER, ALL PARTIES
ALSO EXPRESSED CONCERN OVER THE AMOUNT OF MONEY THAT HAS BEEN SPENT ON THE SITE TO DATE. SPECIFICALLY, FOR
THE REMEDIAL INVESTIGATION/FEASIBILITY STUDY (RI/FS) CONDUCTED BY Us EPA'S CONTRACTOR, AND THE EXPENSES
INCURRED BY EACH OF THE INVOLVED PARTIES FOR ACTIONS RELATING TO THE CONTAMINATION PROBLEM.
A. RESPONSE: Us EPA WISHES TO EXTEND THANKS TO ALL PARTIES FOR THEIR SUPPORT OF ITS SELECTED REMEDIAL
ALTERNATIVE FOR THE SITE. IT IS HOPED THAT AN EXPEDITED AGREEMENT CAN BE REACHED AND THE REMEDIAL ACTION
IMPLEMENTED IN A TIMELY MANNER. WHILE Us EPA UNDERSTANDS THE CONCERN OVER COSTS THAT HAVE BEEN SPENT TO
DATE, IT ALSO RECOGNIZES THAT THE INCURRED COSTS COULD NOT HAVE BEEN AVOIDED. STUDIES OF THE NATURE REQUIRED
TO FULLY IDENTIFY THE EXTENT OF CONTAMINATION AT THE SITE TEND TO BE QUITE EXPENSIVE. THE COST OF THE RI/FS
FOR THIS SITE IS WITHIN THE AVERAGE RANGE FOR AN RI/FS. THE COSTS INCURRED BY INDIVIDUAL PARTIES RELATED TO
THE CONTAMINATION HAVE, FOR THE MOST PART, BEEN NECESSARY TO ADDRESS THE MORE IMMEDIATE PROBLEMS POSED BY THE
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CONTAMINATION OF THE CITY'S WELL FIELD.
B. COMMENT: WAUSAU CHEMICAL CORPORATION HAS REQUESTED SPECIFIC DIRECTION FROM Us EPA AND WDNR BE INCLUDED IN
THE ROD AS TO THE FUTURE OPERATION OF ITS GROUNDWATER EXTRACTION SYSTEM IN LIGHT OF THE FACT THAT THE
SELECTED ALTERNATIVE DOES NOT INCLUDE THE CONTINUED PUMPAGE OF GROUNDWATER IN THE VICINITY OF THE WAUSAU
CHEMICAL PROPERTY.
B. RESPONSE: THE SELECTED REMEDY CALLS FOR THE REMOVAL OF ALL GROUNDWATER EXTRACTION SYSTEMS, OTHER THAN CITY
WELL 3, FROM THE EAST WELL FIELD. THIS WILL INCLUDE THE WAUSAU CHEMICAL EXTRACTION SYSTEM. THIS SUBJECT IS
ALSO ADDRESSED IN SECTION IX-THE SELECTED REMEDY, OF THE ROD AND IS QUOTED BELOW:
THE FINAL REMEDY ALSO WILL REQUIRE THAT EXISTING GROUNDWATER EXTRACTION SYSTEMS CURRENTLY OPERATING IN THE
EAST WELL FIELD, OTHER THAN CITY SUPPLY WELL CW3, CEASE OPERATION ONCE THE SVE SYSTEM IS INSTALLED. THIS IS
NECESSARY IN ORDER TO OBTAIN THE DESIRED RESULT OF PURGING CONTAMINANTS FROM THE AQUIFER UTILIZING CW3.
GROUNDWATER MODELING PERFORMED DURING THE FS INDICATED THAT COMPETING EXTRACTION SYSTEMS COULD CAUSE
CONTAMINANTS TO GET TRAPPED AT THE GROUNDWATER DIVIDE CREATED BY MULTIPLE PUMPING SYSTEMS, AND REQUIRE LONGER
PURGE TIME TO REMEDIATE THE AQUIFER.
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#TABLES AND ATTACHMENTS
TABIiE 1
EXISTING REPORTS ON TCAUSAU GROUNDTCATER CONTAMINATION SITE
1. GROUNDWATER INVESTIGATION, (FOR CITY OF WAUSAU), BECHLER HOPPE ENGINEERS, INC., 1983.
2. SUBSURFACE EXPLORATION AND TESTING PROGRAM TO EVALUATE GROUND WATER QUALITY AT THE WAUSAU CHEMICAL
FACILITIES IN WAUSAU CHEMICAL FACILITIES IN WAUSAU, WISCONSIN, (FOR WAUSAU CHEMICAL COMPANY), STS
CONSULTANTS, LTD., 1984.
3. HYDROGEOLOGICAL INVESTIGATION OF VOLATILE ORGANIC CONTAMINATION IN WAUSAU, WISCONSIN MUNICIPAL
WELLS, (FOR Us EPA), ROY F. WESTON, INC., SEPTEMBER, 1985.
4. INVESTIGATION OF AN ABANDONED CITY OF WAUSAU LANDFILL, FEBRUARY, 1986.
5. EXISTING CONDITIONS REPORT AND EXPLORATION PROGRAM, EAST MUNICIPAL WELL FIELD, WAUSAU, WISCONSIN,
(FOR WDNR), TWIN CITY TESTING CORPORATION, AUGUST, 1986.
6. VOC GROUNDWATER INVESTIGATION AT THE FORMER WAUSAU ENERGY FACILITY IN WAUSAU, WISCONSIN, (FOR WAUSAU
ENERGY CORPORATION), FOTH & VAN DYKE AND ASSOCIATES, INC., JULY, 1986.
7. HYDROGEOLOGICAL INVESTIGATION OF THE ALLUVIAL AQUIFER BENEATH CITY WELL SIX, WAUSAU, WISCONSIN,
(FOR CITY OF WAUSAU AND MARATHON ELECTRIC), RMT, INC., AND GERAGHTY & MILLER, INC., JULY, 1987.
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MEDIUM
GROUNDWATER
TABLE 2
TARGET COMPOUNDS LIST CHEMICALS DETECTED
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
CHEMICAL CONCENTRATION
CHEMICAL
ALL LOCATIONS
VOLATILE
CHLOROMETHANE
VINYL CHLORIDE
METHYLENE CHLORIDE
ACETONE
1,1-DICHLOROETHENE
1,1-DICHLOROETHANE
1,2-DICHLOROETHENE (TOTAL)
CHLOROFORM
2-BUTANONE
1,1,1-TRICHLOROETHANE
CARBON TETRACHLORIDE
TRICHLORETHENE
1,1,2-TRICHLOROETHANE
BENZENE
4-METHYL-2-PENTANONE
TETRACHLOROETHENE
TOLUENE
CHLOROBENZENE
ETHYL BENZENE
XYLENES (TOTAL)
MINIMUM MAXIMUM
(UG/L) (UG/L)
GEOMETRIC
MEAN
(UG/L)
4
3
1
2
—
—
1
2
—
1
2
1
2
18
—
1
2
2
3
16
7
6
190
3070
2
3
1300
44
5
53
69
4200
4
310
2
2440
890
54
440
2000
5
4
8
11
—
—
20
11
—
3
19
29
2
125
—
45
46
7
53
428
-------
TABIiE 2 (CONT)
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
TOTAL
POSITIVE DETECTION
134
VOLATILE
CHLOROMETHANE
VINYL CHLORIDE
METHYLENE CHLORIDE
ACETONE
1,1-DICHLOROETHENE
1,1-DICHLOROETHANE
1,2-DICHLOROETHENE (TOTAL)
CHLOROFORM
2-BUTANONE
1,1,1-TRICHLOROETHANE
CARBON TETRACHLORIDE
TRICHLORETHENE
1,1,2-TRICHLOROETHANE
BENZENE
4-METHYL-2-PENTANONE
TETRACHLOROETHENE
TOLUENE
CHLOROBENZENE
ETHYL BENZENE
XYLENES (TOTAL)
2
4
8
11
1
1
48
6
1
16
3
68
5
5
1
53
5
6
4
6
CHEMICAL CONCENTRATION
SEMIVOLATILE
PHENOL
NAPTHALENE
2-METHYLNAPTHALENE
FLUORENE
PENTACHLOROPHENOL
PHENANTHRENE
BIS (2-ETHYLHEXYL) PHTHALATE
(UG/L)
(UG/L)
2
22
23
4
6
4
19
(UG/L)
-------
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
SEMIVOLATILE
PHENOL
NAPTHALENE
2-METHYLNAPTHALENE
FLUORENE
PENTACHLOROPHENOL
PHENANTHRENE
BIS (2-ETHYLHEXYL) PHTHALATE
PESTICIDE/PCB
NONE DETECTED
TOTAL
31
POSITIVE DETECTION
TOTAL
31
CHEMICAL
METAL/CN (B)
BARIUM
CHROMIUM
IRON
MANGANESE
ZINC
CHEMICAL
METAL/CN (B)
BARIUM
CHROMIUM
IRON
MANGANESE
ZINC
CHEMICAL CONCENTRATION
MINIMUM MAXIMUM
(UG/L) (UG/L)
GEOMETRIC
MEAN
(UG/L)
206
28
169
69
2750
325
594
18100
6100
2860
259
77
1800
937
2800
NUMBER LOCATION SAMPLED FOR ANALYSIS
TOTAL POSITIVE DETECTION
32
3
3
17
25
2
-------
TABIiE 2 (CONT)
PRODUCTION WEIiS
CW3, CW4, CW6
VOLATILE
ACETONE
1,2-DICHLOROETHENE (TOTAL)
TRICHLOROETHENE
TETRACHLOROETHENE
CHLOROBENZENE
MINIMUM
(UG/L)
1
53
7
MAXIMUM
(UG/L)
16
20
150
14
15
GEOMETRIC
MEAN
(UG/L)
9
100
13
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
VOLATILE
ACETONE
1,2-DICHLOROETHENE (TOTAL)
TRICHLOROETHENE
TETRACHLOROETHENE
CHLOROBENZENE
TOTAL
3
POSITIVE DETECTION
SEMIVOLATILE
NON DETECTED
PESTICIDE/PCB
NONE DETECTED
-------
TABIiE 2 (CONT)
CHEMICAL CONCENTRATION
CHEMICAL
METAL/CN
IRON
MANGANESE
CHEMICAL
IRON
MANGANESE
CHEMICAL
GEOMETRIC
SURFACE SOILS
VOLATILE
METHYLENE CHLORIDE
1,1,1-TRICHLOROETHANE
TETRACHLOROETHENE
XYLENES (TOTAL)
MINIMUM MAXIMUM GEOMETRIC
MEAN
(UG/L) (UG/L) (UG/L)
957
1610
5300
2920
2110
2110
NUMBER LOCATION SAMPLED FOR ANALYSIS
TOTAL POSITIVE DETECTION
3
CHEMICAL CONCENTRATION
MINIMUM MAXIMUM
(UG/L) (UG/L)
MEAN
(UG/L)
64
190
3
3
4
110
CHEMICAL
VOLATILE
NUMBER LOCATION SAMPLED FOR ANALYSIS
TOTAL POSITIVE DETECTION
METHYLENE CHLORIDE
1,1,1-TRICHLOROETHANE
TETRACHLOROETHENE
XYLENES (TOTAL)
-------
MEDIUM
SURFACE SOILS
CHEMICAL
CHEMICAL CONCENTRATION
MINIMUM MAXIMUM
(UG/KG) (UG/KG)
SEMIVOLATILE
PHENOL
4-METHYLPHENOL
BENZOIC ACID
NAPHTHALENE
2-METHYLNAPHTHALENE
ACENAPHTHYLENE
ACENAPHTHENE
DIBENZOFURAN
FLUORENE
PHENANTHRENE
ANTHRACENE
FLOURANTHENE
PYRENE
BUTYLBENZYLPHTHALATE
BENZO (A) ANTHRACENE
BIS (2-ETHYLHEXYL) PHTHALATE
CHRYSENE
DI-N-OCTYLPHTHALATE
BENZO (B) FLUORANTHENE
BENZO (K) FLUORANTHENE
BENZO (A) PYRENE
INDENO (1,2,3-CD) PYRENE
DIBENZ (A,H) ANTHRACENE
BENZO (G,H,I) PERYLENE
PESTICIDE/PCB
NOT ANALYZED
METAL/CN
NOT ANALYZED
89
—
—
37
32
2
51
38
100
200
32
200
150
59
110
150
390
—
250
—
100
210
—
230
93
200
160
720
770
110
69
180
120
2500
480
6600
2900
390
2400
1600
3200
380
5400
1600
2700
1200
390
1400
GEOMETRIC
MEAN
(UG/KG)
90
192
264
22
59
82
109
651
155
1300
910
150
749
489
861
1380
604
614
655
-------
SURFACE WATER (BOS CREEK)
MINIMUM MAXIMUM GEOMETRIC
MEAN
VOLATILE (UG/L) (UG/L) (UG/L)
1,2-DICHLOROETHENE (TOTAL) 11 1
TRICHLOROETHENE 1 110 41
TETRACHLOROETHENE 13 2
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL TOTAL POSITIVE DETECTION
12
1,2-DICHLOROETHENE (TOTAL) 2
TRICHLOROETHENE 10
TETRACHLOROETHENE 2
SEMIVOLATILE
NOT ANALYZED
PESTICIDE/PCB
NOT ANALYZED
METAL/CN
NOT ANALYZED
-------
TABLE 2 (CONTINUED)
MEDIUM
WISCONSIN RIVER
CHEMICAL
CHEMICAL CONCENTRATION
MINIMUM MAXIMUM
(UG/L) (UG/L)
GEOMETRIC
MEAN
(UG/L)
1,2-DICHLOROETHENE (TOTAL)
TRICHLOROETHENE
TETRACHLOROETHENE
CHEMICAL
NUMBER LOCATION SAMPLED FOR ANALYSIS
TOTAL POSITIVE DETECTION
4
1,2-DICHLOROETHENE (TOTAL)
TRICHLOROETHENE
TETRACHLOROETHENE
SEMIVOLATILE
NOT ANALYZED
PESTICIDE/PCB
NOT ANALYZED
METAL/CN
NOT ANALYZED
MEDIUM
SEDIMENT - BOS CREEK
VOLATILE
ACETONE
1,2-DICHLOROETHENE (TOTAL)
TRICHLOROETHENE
tOLUENE
MINIMUM
(UG/KG)
18
6
6
MAXIMUM
(UG/KG)
190
200
17
7
GEOMETRIC
MEAN
(UG/KG)
58
51
59
-------
CHEMICAL
NUMBER LOCATION SAMPLED FOR ANALYSIS
TOTAL POSITIVE DETECTION
11
ACETONE
1,2-DICHLOROETHENE (TOTAL)
TRICHLOROETHENE
TOLUENE
SEMIVOLATILE
NONE DETECTED
PESTICIDE/PCB
NONE DETECTED
METALS
NOT ANALYZED
SUBSURFACE SOILS
VOLATILE
CHEMICAL
METHYLENE CHLORIDE
TRICHLOROETHENE
TETRACHLOROETHENE
TOLUENE
ETHYLBENZENE
XYLENES (TOTAL)
TOTAL
3
TOTAL
3
TOTAL
29
MINIMUM MAXIMUM
(UG/KG) (UG/KG)
GEOMETRIC
MEAN
(UG/KG)
1
4
1
1
4
2
2000
10
3500
46
2900
21000
43
6
77
5
37
22
-------
CHEMICAL
NUMBER LOCATION SAMPLED FOR ANALYSIS
TOTAL POSITIVE DETECTION
29
VOLATILE
CHEMICAL
METHYLENE CHLORIDE
TRICHLOROETHENE
TETRACHLOROETHENE
TOLUENE
ETHYLBENZENE
XYLENES (TOTAL)
SEMIVOLATILE
PHENOL
NAPTHALENE
2-METHYLNAPHTALENE
MINIMUM MAXIMUM
(UG/KG) (UG/KG)
320
4900
16000
5
3
12
9
3
7
GEOMETRIC
MEAN
(UG/KG)
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
PHENOL
NAPTHALENE
2-METHYLNAPHTALENE
CHEMICAL
DIMETHYLPHTHALATE
FLUORENE
PHENANTHRENE
ANTHRACENE
DI-N-BUTYLPHTHALATE
FLOURANTHENE
PYRENE
BENZO (A) ANTHRACENE
CHRYSENE
BIS(METHYLHEXYL) PHTHALATE
TOTAL
29
POSITIVE DETECTION
CHEMICAL CONCENTRATION
MINIMUM
MAXIMUM
(UG/L) (UG/L)
110
63
63
48
58
30
31
98
130
45
140
1600
2600
120
76
1400
1300
660
750
84
GEOMETRIC
MEAN
(UG/L)
120
320
260
85
66
220
210
250
290
60
-------
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
TOTAL
29
POSITIVE DETECTION
DIMETHYLPHTHALATE
FLUORENE
PHENANTHRENE
ANTHRACENE
DI-N-BUTYLPHTHALATE
FLOURANTHENE
PYRENE
BENZO (A) ANTHRACENE
CHRYSENE
BIS(METHYLHEXYL) PHTHALATE
2
2
11
6
2
15
12
6
6
5
TABLE 2 (CONTINUED)
CHEMICAL CONCENTRATION
CHEMICAL
MINIMUM
MAXIMUM
(UG/L) (UG/L)
GEOMETRIC
MEAN
(UG/L)
BENZO (B) FLUORANTHENE 110 680
BENZO (K) FLUORANTHENE 100 760
BENZO (A) PYRENE 120 750
INDENO (1,2,3-CD) PYRENE 130 680
DIBENZ (A,H) ANTHRACENE — 74
BENZO (G,H,I) PERYLENE 130 800
220
210
250
220
270
-------
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
TOTAL
POSITIVE DETECTION
BENZO (B) FLUORANTHENE
BENZO (K) FLUORANTHENE
BENZO (A) PYRENE
INDENO (1,2,3-CD) PYRENE
DIBENZ (A,H) ANTHRACENE
BENZO (G,H,I) PERYLENE
PESTICIDE/PCB
10
9
8
6
1
5
NOT ANALYZED
METAL/CN
COPPER
MG/KG MG/KG MG/KG
107
MEDIUM
LANDFILL REFUSE
MINIMUM MAXIMUM
GEOMETRIC
MEAN
METHYLENE CHLORIDE
ACETONE
1,2-DICHLOROETHENE
TRICHLOROETHENE
TOLUENE
ETHYL BENZENE
XYLENES (TOTAL)
9
71
21
36
3
2
4
1900
160
220
160000
750
4
24
70
100
67
680
60
3
13
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
TOTAL
15
POSITIVE DETECTION
METHYLENE CHLORIDE
ACETONE
1,2-DICHLOROETHENE
TRICHLOROETHENE
TOLUENE
ETHYL BENZENE
XYLENES (TOTAL)
-------
SEMIVOLATILE
PHENOL
2-CHLOROPHENOL
1,2-DICHLOROBENZENE
2-METHYLPHENOL
4-METHYLPHENOL
ISOPHORONE
1,2,4-TRICHLOROBENZENE
NAPTHALENE
4-CHLORO-3-METHYLPHENOL
2-METHYLNAPTHALENE
2-CHLORONAPTHALENE
ACENAPTHYLENE
ACENAPHTHENE
DIBENZOFURAN
FLUORENE
PENTACHLOROPHENOL
PHENANTHRENE
ANTHRACENE
FLUORANTHENE
PYRENE
BUTYLBENZYLPHTHALATE
BENZO (A) ANTHRACENE
BIS (2-ETHYLHEXYL) PHTHALATE
CHRYSENE
BENZO (B) FLUORANTHENE
BENZO (K) FLUORANTHENE
BENZO (A) PYRENE
MINIMUM
(UG/KG)
—
—
—
—
—
—
—
49
—
65
—
—
45
19
82
820
170
19
60
63
130
420
110
54
410
430
480
MAXIMUM
(UG/KG)
2200
2200
210
75
830
130
1200
1300
2300
890
170
130
730
330
500
32000
15000
2200
45000
49000
2300
24000
54000
25000
25000
25000
25000
GEOMETRIC
MEAN
(UG/KG)
150
150
180
63
186
2900
1100
250
1600
1700
500
1400
860
970
1700
1400
1200
-------
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
TOTAL
15
POSITIVE DETECTION
PHENOL
2-CHLOROPHENOL
1,2-DICHLOROBENZENE
2-METHYLPHENOL
4-METHYLPHENOL
ISOPHORONE
1,2,4-TRICHLOROBENZENE
NAPTHALENE
4-CHLORO-3-METHYLPHENOL
2-METHYLNAPTHALENE
2-CHLORONAPTHALENE
ACENAPTHYLENE
ACENAPHTHENE
DIBENZOFURAN
FLUORENE
PENTACHLOROPHENOL
PHENANTHRENE
ANTHRACENE
FLUORANTHENE
PYRENE
BUTYLBENZYLPHTHALATE
BENZO (A) ANTHRACENE
BIS (2-ETHYLHEXYL) PHTHALATE
CHRYSENE
BENZO (B) FLUORANTHENE
BENZO (K) FLUORANTHENE
BENZO (A) PYRENE
PESTICIDE/PCB
1
1
1
1
1
1
1
7
1
7
1
1
3
7
5
5
11
10
12
12
3
10
10
12
10
10
9
TOTAL
6
(UG/L)
(UG/L)
(UG/L)
AROCHLOR 1260
850 2300
1400
AROCHLOR 1260
TOTAL POSITIVE DETECTION
2
-------
TABLE 2 (CONT)
CHEMICAL CONCENTRATION
CHEMICAL
MINIMUM MAXIMUM
(UG/L) (UG/L)
GEOMETRIC
MEAN
(UG/L)
ARSENIC
CHROMIUM
COPPER
MERCURY
ZINC
107
0.5
323
76
1130
1410
1.9
3260
383
1.2
2160
NUMBER LOCATION SAMPLED FOR ANALYSIS
CHEMICAL
TOTAL POSITIVE DETECTION
14
ARSENIC
ChROMIUM
COPPER
MERCURY
ZINC
-------
TABLE 4
CRITICAL TOXICITY VALUES FOR INDICATOR CONTAMINANTS (A)
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
REFERENCE DOSE (MG/KG/DAY)
ORAL
SUBCHRONIC
CHRONIC
INDICATOR CONTAMINANT
TETRACHLOROETHENE
(PCE)
TRICHLOROETHENE
(TCE)
1,2-DICHLOROETHENE (TOTAL)
(DCE)
l.OE-02
INHALATION
SUBCHRONIC
CHRONIC
TETRACHLOROETHENE
(PCE)
TRICHLOROETHENE
(TCE)
1,2-DICHLOROETHENE (TOTAL)
(DCE)
CHRONIC
EPA WEIGHT OF EVIDENCE
CLASSIFICATION (B)
INDICATOR CONTAMINANT
TETRACHLOROETHENE
(PCE)
TRICHLOROETHENE
(TCE)
1,2-DICHLOROETHENE (TOTAL)
(DCE)
B2
B2
D
-------
CARCINOGENIC POTENCY FACTOR
(MG/KG/DAY) - 1
ORAL INHALATION
INDICATOR CONTAMINANT
TETRACHLOROETHENE 5.10E-02 3.30E-03
(PCE)
TRICHLOROETHENE 1.10E-02 1.3E-02
(TCE)
1,2-DICHLOROETHENE (TOTAL)
(DCE)
(A) - VALUES OBTAINED FROM INTEGRATED RISK INFORMATION SYSTEM (IRIS) (4/89).
(B) - (HUMAN CARCINOGEN) SUFFICIENT EVIDENCE FROM EPIDEMIOLOGIC STUDIES
TO SUPPORT A CASUAL ASSOCIATION BETWEEN EXPOSURE CANCER.
GROUP Bl - (PROBABLE HUMAN CARCINOGEN) LIMITED EVIDENCE OF CARCINOGENICITY IN HUMANS FROM
EPIDEMIOLOGICAL STUDIES.
GROUP B2 (PROBABLE HUMAN CARCINOGEN) SUFFICIENT EVIDENCE OF CARCINOGENICITY IN HUMANS.
GROUP C (PROBABLE HUMAN CARCINOGEN) LIMITED EVIDENCE OF CARCINOGENICITY IN ANIMALS.
GROUP D (NOT CLASSIFIED) INADEQUATE EVIDENCE OF CARCINOGENICITY IN ANIMALS.
GROUP E (NO EVIDENCE OF CARCINOGENICITY IN HUMANS) NO EVIDENCE FOR
CARCINOGENICITY IN AT LEAST TWO ADEQUATE ANIMAL TESTS OR IN BOTH
EPIDEMIOLOGIC AND ANIMAL STUDIES.
-------
TABLE 5
MAXIMUM CONCENTRATIONS AND RESULTING POTENTIAL CANCER RISKS
FOR CONTAMINANTS AND PATHWAYS OF CONCERN
AT THE TCAUSAU GROUNDWATER CONTAMINATION SITE
EXPOSURE PATHWAY/ MAXIMUM POTENTIAL
CONTAMINANT OF CONCERN CONCENTRATION CANCER RISK
PCE .5 UG/L 8.9 X (10-7)
TCE .5 UG/L 6.3 X (10-7)
EXPOSURE PATHWAY/RISK TOTAL: 1.5 X (10-6)
2) GROUNDWATER (PRIVATE WELLS) (B)
PCE 2440 UG/L 4.5 X (10-3)
TCE 4200 UG/L 5.2 X (10-3)
EXPOSURE PATHWAY/RISK TOTAL:
3) AIR EMISSIONS FROM STRIPPERS
PCE 1.3 UG/M (3) 4.8 X (10-7)
TCE .37/M (3) 1.2 X (10-6)
EXPOSURE PATHWAY/RISK TOTAL: 1.7 X (10-6)
A: CONCENTRATIONS OF INDICATOR CONTAMINANTS IN THE MUNICIPAL SYSTEM WERE
ASSUMED TO BE EQUAL TO LABORATORY ANALYTICAL METHOD DETECTION LIMITS.
B: CONCENTRATIONS OF INDICATOR CONTAMINANTS USED IN THE PRIVATE WELL
SCENARIO WERE THE MAXIMUM CONCENTRATIONS DETECTED IN GROUNDWATER AT THE SITE.
-------
TABLE 6
REMEDIAL ACTION ALTERNATIVES
ALTERNATIVE 1 NO ACTION
ALTERNATIVE 2 GROUNDWATER EXTRACTION AND TREATMENT WITH AIR STRIPPING
AND DISCHARGE TO THE WISCONSIN RIVER.
ALTERNATIVE 3 IN-SITU BIORECLAMATION WITH PARTIAL ABOVE GROUND
TREATMENT AND DISCHARGE TO THE WISCONSIN RIVER.
ALTERNATIVE 4 IN-SITU BIORECLAMATION.
ALTERNATIVE 5 ACTIVE SOURCE CONTROL-SOIL VAPOR EXTRACTION.
-------
TABIiE 12
SUMMARY OF PROBABLE COSTS: ALTERNATIVE 2
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
ITEM COST
GROUNDWATER EXTRACTION SYSTEM $ 70,000
STRIPPING TOWER AND APPURTENANCES $ 110,000
VAPOR PHASE CARBON UNIT AND
APPURTENANCES $ 50,000
DISCHARGE SYSTEM $ 40,000
UTILITIES EXCAVATION SPOILS MANAGEMENT $ 15,000
CAPITAL FACILITIES SUBTOTAL $ 285,000
ENGINEERING DESIGN (15%) $ 45,000
CONTRACT AND PROJECT
ADMINISTRATION (25%) $ 70,000
CAPITAL SUBTOTAL $ 400,000
CONTINGENCIES (20%) $ 80,000
CAPITAL TOTAL $ 480,000
ANNUAL OPERATION AND MAINTENANCE COSTS
FIRST YEAR SUBSEQUENT YEARS
WATER LEVELS $ 5,000 $ 5,000
WATER QUALITY $ 26,000 $ 8,000
FLOW MONITORING $ 3,000 $ 3,000
ENERGY $ 6,000 $ 6,000
GENERAL 0 & M LABOR $ 20,000 $ 20,000
REPORTING AND ADMINISTRATION $ 30,000 $ 30,000
CARBON PURCHASE AND
REGENERATION $ 30,000 $ 30,000
0 & M SUBTOTAL $ 120,000 $ 102,000
CONTINGENCIES (20%) $ 24,000 $ 20,000
0 & M TOTAL $ 144,000 $ 122,000
12-YEAR PRESENT WORTH
PRESENT WORTH OF CAPITAL (NOT DISCOUNTED) $ 480,000
PRESENT WORTH OF 0 & M (10% DISCOUNT RATE) $ 850,000
PRESENT WORTH TOTAL $1,330,000
-------
TABIiE 13
SUMMARY OF PROBABLE COSTS: ALTERNATIVE 3
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
ITEM COST
GROUNDWATER EXTRACTION SYSTEM $ 95,000
STRIPPING TOWER AND APPURTENANCES $ 110,000
VAPOR PHASE CARBON UNIT AND
APPURTENANCES $ 50,000
DISCHARGE SYSTEM $ 40,000
INFILTRATION/NUTRIENT SYSTEM $ 90,000
UTILITIES AND EXCAVATION SPOILS
MANAGEMENT $ 10,000
LAB AND PILOT TESTING $ 200,000
CAPITAL FACILITIES SUBTOTAL $ 595,000
ENGINEERING DESIGN (15%) $ 90,000
CONTRACT AND PROJECT
ADMINISTRATION (25%) $ 150,000
CAPITAL SUBTOTAL $ 825,000
CONTINGENCIES (20%) $ 165,000
CAPITAL TOTAL $ 990,000
ANNUAL OPERATION AND MAINTENANCE COSTS
FIRST YEAR SUBSEQUENT YEARS
WATER LEVELS $ 5,000 $ 5,000
WATER QUALITY $ 26,000 $ 8,000
FLOW MONITORING $ 5,000 $ 5,000
ENERGY $ 6,000 $ 6,000
GENERAL 0 & M LABOR $ 40,000 $ 40,000
REPORTING AND ADMINISTRATION $ 30,000 $ 30,000
CARBON PURCHASE AND
REGENERATION $ 40,000 $ 40,000
0 & M SUBTOTAL $ 152,000 $ 134,000
CONTINGENCIES (20%) $ 30,000 $ 27,000
0 & M TOTAL $ 182,000 $ 161,000
6-YEAR PRESENT WORTH
PRESENT WORTH OF CAPITAL (NOT DISCOUNTED) $ 990,000
PRESENT WORTH OF 0 & M (10% DISCOUNT RATE) $ 720,000
PRESENT WORTH TOTAL $1,710,000
-------
SUMMARY OF PROBABLE COSTS: ALTERNATIVE 4
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
ITEM COST
GROUNDWATER EXTRACTION SYSTEM $ 120,000
UTILITIES AND EXCAVATION SPOILS
MANAGEMENT $ 10,000
INFILTRATION/NUTRIENT SYSTEM $ 90,000
UTILITIES AND EXCAVATION SPOILS
MANAGEMENT $ 10,000
LAB AND PILOT TESTING $ 200,000
CAPITAL FACILITIES SUBTOTAL $ 420,000
ENGINEERING DESIGN (15%) $ 65,000
CONTRACT AND PROJECT
ADMINISTRATION (25%) $ 105,000
CAPITAL SUBTOTAL $ 590,000
CONTINGENCIES (20%) $ 120,000
CAPITAL TOTAL $ 710,000
ANNUAL OPERATION AND MAINTENANCE COSTS
FIRST YEAR SUBSEQUENT YEARS
WATER LEVELS $ 5,000 $ 5,000
WATER QUALITY $ 26,000 $ 8,000
FLOW MONITORING $ 5,000 $ 5,000
ENERGY $ 5,000 $ 5,000
GENERAL 0 & M LABOR $ 30,000 $ 30,000
REPORTING AND ADMINISTRATION $ 30,000 $ 30,000
0 & M SUBTOTAL $ 111,000 $ 93,000
CONTINGENCIES (20%) $ 22,000 $ 19,000
0 & M TOTAL $ 133,000 $ 112,000
9-YEAR PRESENT WORTH
PRESENT WORTH OF CAPITAL (NOT DISCOUNTED) $ 710,000
PRESENT WORTH OF 0 & M (10% DISCOUNT RATE) $ 670,000
PRESENT WORTH TOTAL $1,380,000
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SUMMARY OF PROBABLE COSTS: ALTERNATIVE 5
FEASIBILITY STUDY
WAUSAU WATER SUPPLY NPL SITE
WAUSAU, WISCONSIN
CAPITAL COSTS
ITEM COST
WELLS, HEADER AND APPURTENANCES $ 90,000
BLOWER HOUSE, CONTROLS, UTILITIES $ 60,000
OFF-GAS TREATMENT (CARBON) $ 25,000
CAPITAL FACILITIES SUBTOTAL $ 175,000
ENGINEERING DESIGN (20%) $ 29,000
CONTRACT AND PROJECT ADMINISTRATION (25%) $ 36,000
CAPITAL SUBTOTAL $ 210,000
CONTINGENCIES (20%) $ 42,000
CAPITAL TOTAL $ 252,000
OPERATION AND MAINTENANCE COSTS
MONITORING $ 15,000
ENERGY $ 5,000
GENERAL 0 & M LABOR $ 30,000
REPORTING AND ADMINISTRATION $ 45,000
CARBON PURCHASE AND TREATMENT $ 90,000
VAPOR SYSTEM 18 MONTH 0 & M SUBTOTAL $ 185,000
CONTINGENCIES (20%) $ 37,000
VAPOR SYSTEM 18 MONTH 0 & M TOTAL $ 222,000
WELL CW3 AND STRIPPER - ENERGY $ 15,000
- 0 & M $ 3,000
WELL CW6 AND STRIPPER - ENERGY $ 21,000
- 0 & M $ 3,500
CITY WELL AND STRIPPER ANNUAL 0 & M TOTAL $ 42,500
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PRESENT WORTH
PRESENT WORTH OF VAPOR SYSTEM CAPITAL
(NOT DISCOUNTED) $ 252,000
PRESENT WORTH OF VAPOR SYSTEM 0 & M
(NOT DISCOUNTED) $ 222,000
VAPOR SYSTEM PRESENT WORTH TOTAL $ 474,000
PRESENT WORTH OF CW3 COST (6 YEARS) $ 80,000
PRESENT WORTH OF CW6 COST (14 YEARS) $ 180,000
CITY WELL AND STRIPPER PRESENT
WORTH TOTAL $ 260,000
ALTERNATIVE 5 PRESENT WORTH TOTAL $ 734,000
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