EPA Superfund record of decision : Tenth Street dump/junkyard, OU 01, Oklahoma City, OK

              EPA/ROD/R06-90/059
1990
EPA Superfund
Record of Decision:
TENTH STREET DUMP/JUNKYARD
EPA ID: OKD980620967
OU 01
OKLAHOMA CITY, OK
09/27/1990
09/27/90
REGIONAL ADMINISTRATOR
#LD
I. LOCATION AND DESCRIPTION
THE TENTH STREET SITE (THE "SITE") IS LOCATED AT 3200 NE TENTH STREET, IN THE FAR EASTERN
BOUNDARY OF OKLAHOMA CITY, OKLAHOMA (SECTION 31, TOWNSHIP 12 NORTH, RANGE 2 WEST, OF OKLAHOMA
COUNTY). THE SITE IS APPROXIMATELY 3.5 ACRES IN SIZE. IT IS SITUATED IMMEDIATELY SOUTH OF NE
TENTH STREET AND LIES BETWEEN BRYANT AVENUE AND THE NORTH CANADIAN RIVER. STANDISH AVENUE, A
SIDE STREET EAST OF BRYANT, IS THE NORTH-SOUTH STREET CLOSEST TO THE WESTERN BOUNDARY OF THE
SITE (SEE FIGURES 1 & 2). THE SITE IS ALSO SITUATED IN THE 100-YEAR FLOOD PLAIN OF THE NORTH
CANADIAN RIVER. THE AREA IN THE VICINITY OF THE SITE IS USED PRIMARILY FOR INDUSTRIAL PURPOSES.
VEGETATION IN THE AREA IS DIRECTLY RELATED TO THE NORTH CANADIAN RIVER AND TO THE DEGREE OF
URBANIZATION. IT CONSISTS OF MARSH GRASS AND WILLOW AND COTTONWOOD TREES ALONG THE RIVER BANKS.
GRASSCOVERED FIELDS AND LOTS AWAY FROM THE RIVER ARE PUNCTUATED BY VARIETIES OF ELM, BACKJACK,
POST OAK AND OTHER DECIDUOUS TREES. AROUND THE SITE ARE PRIMARILY SHORT GRASSES WHILE THE SITE
ITSELF IS COVERED BY A TALL GRASS.
WITHIN 100 YARDS OF THE WESTERN SITE BOUNDARY IS A RESIDENCE. EAST OF THE SITE ABOUT 75 YARDS
IS A RESIDENCE AND A SALVAGE YARD (FIGURE 2). TWO INDIVIDUALS LIVE AT THE RESIDENCE ADJACENT TO
THE SALVAGE YARD AND ONE INDIVIDUAL LIVES AT THE RESIDENCE WEST OF THE SITE. THERE ARE ABOUT 30
VISITORS PER DAY AT THE SALVAGE YARDS AND ABOUT 4 VISITORS PER DAY AT THE HOME WEST OF THE SITE.
ACCORDING TO A 1985 TRAFFIC COUNT, APPROXIMATELY 16,000 CARS PER DAY PASS THE SITE ON THE NE
TENTH STREET. THE CLOSEST POPULATION CENTERS ARE OKLAHOMA CITY (446,120, 1986 CENSUS RECORDS)
AND DEL CITY (28,523, 1980 CENSUS RECORDS).
THE OKLAHOMA CITY PUBLIC WATER SUPPLY SOURCE IS DRAPER LAKE. DEL CITY USES SURFACEWATER FROM
THUNDERBIRD LAKE AND GROUNDWATER FOR ITS SOURCES OF DRINKING WATER. BOTH DRAPER LAKE AND
THUNDERBIRD LAKE ARE OUTSIDE OF A THREE-MILE RADIUS OF THE SITE. WATER SUPPLY FOR ABOUT 29,218
PEOPLE WITHIN A THREE-MILE RADIUS OF THE SITE IS PROVIDED BY GROUNDWATER FROM THE
GARBER-WELLINGTON FORMATION.
THE NEAREST MAJOR SURFACEWATER BODY IS THE NORTH CANADIAN RIVER, WHICH LIES SOUTH AND EAST OF
THE SITE. REGIONAL DRAINAGE IS TOWARD THE RIVER BUT LOCAL TOPOGRAPHY CAUSES SOME VARIATIONS IN
THIS PATTERN. TWO SOUTHEAST TRENDING TRIBUTARIES ABOUT 200 TO 400 YARDS WEST OF THE SITE BECOME
CONFLUENT AND JOIN THE NORTH CANADIAN RIVER ABOUT 400 YARDS SOUTH OF THE SITE. ABOUT 0.25 MILE
TO THE NORTHEAST OF THE SITE ARE TWO LARGE PONDS WHICH WERE PREVIOUSLY QUARRYING PITS FOR SAND
AND GRAVEL.
THE SITE RESTS ON UNCONSOLIDATED QUATERNARY ALLUVIUM DEPOSITS OF THE NORTH CANADIAN RIVER
(FIGURE 3); ITS THICKNESS RANGES FROM A FEW INCHES UP TO 100 FEET. BENEATH THE SITE, THE
ALLUVIUM IS ABOUT 30 FEET THICK. THE GARBER-WELLINGTON FORMATION UNDERLIES THE ALLUVIUM WITH
THE HENNESSEY SHALE STRATIGRAPHICALLY POSITIONED IN BETWEEN. HOWEVER, THE HENNESSEY SHALE IS
NOT PRESENT UNDERNEATH THE SITE.
THE GARBER-WELLINGTON IS THE MOST IMPORTANT SOURCE OF GROUNDWATER IN THE OKLAHOMA CITY-DEL
CITY-MIDWEST CITY AREA. IN THE VICINITY OF THE SITE, THE BASE OF FRESH WATER IS SLOPED FROM 600
TO 300 FEET ABOVE SEA LEVEL. THE HENNESSEY SHALE IS NOT A SIGNIFICANT AQUIFER BUT THE WATER IS
OF SUFFICIENT YIELD AND QUALITY TO PROVIDE WATER SUPPLIES FOR DOMESTIC AND AGRICULTURAL USE
(GROUNDWATER CLASSIFICATION 2B).
GROUNDWATER BENEATH THE SITE IS PRESENT IN AT LEAST TWO DISTINCT ZONES AS INDICATED BY FIELD
INVESTIGATIONS AND WATER QUALITY DATA. A SHALLOW WATER-BEARING ZONE EXISTS FROM 6 FEET TO AT
LEAST 30 FEET BELOW GROUND SURFACE (BGS). THE WATER TABLE RANGES FROM 6 TO 10 FEET BGS AND
SLOPES GENTLY TO THE SOUTH-SOUTHEAST, TOWARDS THE NORTH CANADIAN RIVER (FIGURE 4). ANOTHER ZONE
IS PRESENT AT ABOUT 160 FEET BGS. THE UPPER AND LOWER BOUNDS OF THIS DEEPER ZONE ARE NOT KNOWN.
NOR IS IT KNOWN IF OTHER WATER BEARING UNITS EXIST BETWEEN THESE SHALLOW AND DEEP ZONES.
#SHEA
II. SITE HISTORY AND ENFORCEMENT ACTIVITIES
EVIDENCE FROM AERIAL PHOTOGRAPHS INDICATE THAT THE AREA WAS OPERATED AS A MUNICIPAL LANDFILL
BETWEEN 1951 AND 1954. FROM ABOUT 1959 TO 1979 MR. RAYMOND COBB LEASED THIS SITE AND OPERATED
IT AS A SALVAGE YARD UNTIL HIS DEATH IN 1979. DURING HIS OPERATION, MATERIALS SUCH AS PAINT
THINNERS, TIRES, AND OLD TRANSFORMERS WERE ACCEPTED IN THE SALVAGE YARD. DIELECTRIC FLUID THAT
CONTAINED POLYCHLORINATED BIPHENYLS (PCBS) WAS DRAINED FROM OLD TRANSFORMERS, STORED IN BARRELS,
AND SOLD. DURING THE RECOVERY PROCESS, SUBSTANTIAL QUANTITIES OF OIL WERE SPILLED ONTO THE
GROUND. AFTER MR. COBB'S DEATH, MR. ROLLING FULLBRIGHT OPERATED THE SITE AS AN AUTOMOBILE
SALVAGE YARD CALLED DEADEYE'S SALVAGE YARD.
IN 1983, THE FIELD INVESTIGATION TEAM OF THE ENVIRONMENTAL PROTECTION AGENCY (EPA) INSPECTED THE
SITE AND OBSERVED ABOUT 20 DRUMS, SOME OF WHICH WERE CORRODED, LEAKING, OR BULGING. LIQUIDS
CONTAINED IN THE DRUMS AND SOILS FROM THE SURROUNDING AREA WERE SAMPLED BY FIT. HIGH
CONCENTRATIONS OF VOLATILE ORGANIC COMPOUNDS, BENZENE, POLYNUCLEAR AROMATICS, METHYLENE
CHLORIDE, METHYLENE PHENOL, ETHANOL, TETRACHLOROETHANE, ACETONE, AND TETRACHLOROETHYLENE WERE
DETECTED IN SOIL. SUBSEQUENT SAMPLING IN 1984 AND 1985 BY THE TECHNICAL ASSISTANT TEAM (TAT) OF
EPA DETECTED HIGH CONCENTRATIONS OF PCBS IN THE SOIL ON AND AROUND THE SITE.
IN AUGUST 1985, THE EPA REGION 6 REGIONAL ADMINISTRATOR APPROVED AN EMERGENCY RESPONSE ACTION TO
REMOVE AND DISPOSE OF ELECTRICAL EQUIPMENT AND DRUMS CONTAINING HAZARDOUS SUBSTANCES. THIS
AUTHORITY ALSO INCLUDED ACTIONS TO DECONTAMINATE AND RELOCATE JUNK AUTOMOBILES, CONSOLIDATE
CONTAMINATED SOILS TO THE CENTER OF THE SITE, GRADE THE SITE FOR EFFECTIVE DRAINAGE, INSTALL A
SYNTHETIC LINER AND CLAY CAP, AND ERECT A SECURITY FENCE AROUND THE SITE.
AFTER COMPLETION OF THE REMOVAL ACTION, THE SITE WAS EVALUATED UNDER THE CRITERIA FOR
DETERMINING PRIORITIES AMONG RELEASES OR THREATENED RELEASES THROUGHOUT THE UNITED STATES FOR
THE PURPOSE OF TAKING REMEDIAL ACTION. IN JANUARY 1987, THE SITE WAS PROPOSED FOR INCLUSION ON
THE NATIONAL PRIORITIES LIST (NPL) DUE TO THE POTENTIAL FOR GROUNDWATER CONTAMINATION. THE SITE
WAS PLACED ON THE NPL IN JULY 1987.
A REMEDIAL INVESTIGATION AND FEASIBILITY STUDY (RI/FS) WAS CONDUCTED BY EPA REGION 6 IN SPRING
1989 TO IDENTIFY THE TYPES, QUANTITIES AND LOCATIONS OF CONTAMINANTS, TO IDENTIFY THE RISK FROM
THESE CONTAMINANTS AND TO ADDRESS THE CONTAMINATION PROBLEMS. THE RI CONSISTED OF A
COMPREHENSIVE FIELD SAMPLING AND ANALYSIS PROGRAM FOLLOWED BY VALIDATION AND EVALUATION OF THE
DATA COLLECTED. THE RI REPORT WAS FINALIZED AND RELEASED TO THE PUBLIC IN MARCH 1990.
THE RESULTS OF THE RI IDENTIFY THAT:
• PCBS ARE THE CONTAMINANTS OF CONCERN AT THE SITE, BASED ON CONCENTRATION AND RISK;
THE PREDOMINANT PCB SPECIES PRESENT IS AROCLOR 1260;
• CONTAMINATION IS LIMITED TO SOIL AT THE SITE; AND
• GROUNDWATER OR SURFACEWATER CONTAMINATION WAS NOT DETECTED.
THE FEASIBILITY STUDY REPORT AND RISK ASSESSMENT REPORT FOR THIS SITE WERE COMPLETED IN JULY
1990. IN AUGUST 1990, THE FS REPORT AND THE RISK ASSESSMENT REPORT WERE RELEASED TO THE PUBLIC
ALONG WITH THE PROPOSED PLAN. A 30-DAY PUBLIC COMMENT PERIOD WAS PROVIDED, ENDING ON SEPTEMBER
8, 1990.
SEARCHES FOR POTENTIALLY RESPONSIBLE PARTIES (PRPS) HAVE BEEN CONDUCTED AND TWO POSSIBLE PRPS,
MR. SULLIVAN SCOTT AND MR. ELMER COBB, WERE IDENTIFIED. UPON FURTHER INVESTIGATION, OTHER PRPS
MAY BE IDENTIFIED. THE KNOWN PRPS WERE NOTIFIED IN WRITING ON MARCH 23, 1989 VIA A GENERAL
NOTICE LETTER AND GIVEN THE OPPORTUNITY TO CONDUCT THE RI/FS UNDER THE SUPERVISION OF EPA.
HOWEVER, NEITHER HAS ELECTED TO UNDERTAKE THESE ACTIVITIES.
#HCP
III. HIGHLIGHTS OF COMMUNITY PARTICIPATION
A COMMUNITY RELATIONS PLAN FOR THE SITE WAS DEVELOPED AND FINALIZED IN JUNE 1989. THIS DOCUMENT
LISTS CONTACTS AND INTERESTED PARTIES THROUGHOUT GOVERNMENT AND THE LOCAL COMMUNITY, AND
LOCATIONS FOR INFORMATION REPOSITORIES. IT ALSO ESTABLISHES COMMUNICATION PATHWAYS TO ENSURE
TIMELY DISSEMINATION OF PERTINENT INFORMATION. FACT SHEETS OUTLINING THE RI AND ITS PROGRESS
WERE DISTRIBUTED. AN OPEN HOUSE TO PROVIDE INFORMATION ON THE RI ACTIVITIES WAS HELD IN
SEPTEMBER 1989. THE RI REPORT WAS RELEASED TO THE PUBLIC IN MARCH 1990. THE FS REPORT, RISK
ASSESSMENT REPORT, AND THE PROPOSED PLAN WERE RELEASED TO THE PUBLIC IN AUGUST 1990. AN OPEN
HOUSE TO PROVIDE INFORMATION ON THE FS AND THE PROPOSED PLAN WAS HELD ON AUGUST 7, 1990. ALL OF
THESE DOCUMENTS WERE MADE AVAILABLE IN THE ADMINISTRATIVE RECORD AND INFORMATION REPOSITORIES
MAINTAINED AT THE OKLAHOMA CITY PUBLIC WORKS DEPARTMENT, OKLAHOMA STATE DEPARTMENT OF HEALTH,
AND THE RALPH ELLISON LIBRARY. A PUBLIC COMMENT PERIOD WAS HELD FROM AUGUST 9, 1990 TO
SEPTEMBER 7, 1990. A PUBLIC MEETING WAS HELD ON AUGUST 14, 1990 TO PRESENT THE RESULTS OF THE
RI/FS AND THE PREFERRED ALTERNATIVE AS PRESENTED IN THE PROPOSED PLAN FOR THE SITE. ALL
COMMENTS WHICH WERE RECEIVED BY EPA WITHIN THE COMMENT PERIOD, INCLUDING THOSE EXPRESSED
VERBALLY AT THE PUBLIC MEETING, ARE ADDRESSED IN THE RESPONSIVENESS SUMMARY SECTION OF THE
RECORD OF DECISION.
#SRRA
IV. SCOPE AND ROLE OF RESPONSE ACTION WITHIN SITE STRATEGY
AS CHARACTERIZED BY THE RI, THE PROBLEMS AT THE TENTH STREET SUPERFUND SITE ARE LIMITED TO SOIL
CONTAMINATION. THE SITE WAS DETERMINED TO POSE A PRINCIPAL THREAT BECAUSE OF THE POTENTIAL FOR
DIRECT CONTACT WITH THE CONTAMINATED SOIL AND THE SOIL'S POTENTIAL IMPACT ON GROUNDWATER. THE
SCOPE OF THE RESPONSE ACTION IS TO ADDRESS THE PRINCIPAL THREAT AT THE SITE BY PREVENTING
CURRENT OR FUTURE EXPOSURE TO THE CONTAMINATED SOIL THROUGH TREATMENT AND/OR CONTAINMENT, AND
REDUCING OR CONTROLLING THE POTENTIAL MIGRATION OF CONTAMINANTS FROM THE SOIL TO GROUNDWATER.
#SSC
V. SUMMARY OF SITE CHARACTERISTICS
ANALYSES OF SOIL, GROUNDWATER, AND SURFACEWATER FROM THE SITE AND ADJACENT AREAS INDICATE
CONTAMINANTS AT THE SITE ARE PRIMARILY RELATED TO PCBS. OTHER CONTAMINANTS DO NOT POSE A HEALTH
RISK, BASED ON THE RISK ASSESSMENT. CONTAMINATION IS LIMITED TO SOIL AT THE SITE.
SOIL
SOIL SAMPLES WERE COLLECTED AT SELECTED INTERVALS DURING THE DRILLING OF FIVE GROUNDWATER
MONITORING WELLS AND 26 SHALLOW BORING; OF THESE 31 LOCATIONS, TWO MONITORING WELLS AND 11
SHALLOW BORINGS ARE OFFSITE (FIGURE 5). A SUMMARY OF THE PCB SOIL SAMPLING RESULTS IS LISTED IN
TABLE 1. THE CONCENTRATIONS OF PCBS RANGE FROM 41 PPM TO AS MUCH AS 1700 PPM, WHILE THE AVERAGE
CONCENTRATION IS 110 PPM. FIGURE 6 SHOWS TOTAL AROCLOR CONCENTRATIONS WITHOUT SPECIES
DIFFERENTIATION.
LATERALLY, PCBS ARE GENERALLY LOCATED MORE TOWARDS THE CENTRAL PORTION OF THE SITE. VERTICALLY,
PCBS ARE PRESENT FROM 1 FT TO AS MUCH AS 8 FT BELOW THE GROUND SURFACE (INCLUDING THE THICKNESS
OF THE CAP). EXCLUDING THE CAP, THE MAXIMUM DEPTH OF CONTAMINATION OR THICKNESS OF CONTAMINATED
SOIL BELOW THE PROTECTIVE CAP IS ABOUT 6.7 FT. IN GENERAL, CONTAMINATED SOIL IS ABOUT 1 FOOT
THICK AT THE CAP PERIPHERY, WHILE IT IS BETWEEN 3 TO 6.7 FT THICK TOWARDS THE CENTER OF THE CAP.
THE INCREASE IN THE THICKNESS OF CONTAMINATED SOIL FROM 2 FEET IN 1985 TO 6.7 FEET IN 1989
(FIGURE 7), IS DUE TO GRADING OF SOIL TOWARDS THE CENTER OF THE SITE DURING CONSTRUCTION OF THE
PROTECTIVE CAP. CONTAMINATION GREATER THAN THE 25 PPM PCB REMEDIAL GOAL WAS NOT DETECTED AT
DEPTHS GREATER THAN 6 FEET. THE DEEPEST POINT WHERE CONTAMINATION WAS DETECTED IS ABOUT 3 FT
ABOVE THE GROUNDWATER TABLE.
DURING PREPARATION OF THE FEASIBILITY STUDY REPORT, REVIEW OF THE 1985 REMOVAL AFTER-ACTION
REPORT REVEALED THAT PCB CONTAMINATION WAS DETECTED IN THE ROAD RIGHT-OF-WAY AT A DEPTH
APPROXIMATELY 4 FT AND THE PROTECTIVE CAP WAS EXTENDED TO THE EDGE OF THE NE TENTH STREET. THIS
AREA OF CONTAMINATION IS BETWEEN THE NORTH FENCE LINE OF THE SITE AND THE EDGE OF THE NE TENTH
STREET. ADDITIONAL SAMPLING IS PLANNED AND RESULTS WILL BE USED TO ESTIMATE THE ADDITIONAL
VOLUME OF CONTAMINATED SOIL TO BE ADDRESSED IN THE REMEDIAL ACTION.
ONLY LOCAL CONCENTRATIONS OF POLYNUCLEAR AROMATIC HYDROCARBONS (PAHS) WERE DETECTED (TABLES 2 -
8). THE LEVELS ARE SLIGHTLY ELEVATED AND ARE CONSISTENTLY ASSOCIATED WITH BURNED RUBBLE AND
LANDFILL DEBRIS. THE SAMPLES IN WHICH PAHS WERE DETECTED CONTAINED BURNED WOOD, TIRES, AND
OTHER DEBRIS TYPICAL OF LANDFILLS.
LEAD CONCENTRATIONS ARE SLIGHTLY ELEVATED IN ONSITE AREAS BUT ARE WITHIN NORMAL RANGES IN THE
OFFSITE AREAS. THE SLIGHTLY ELEVATED CONCENTRATIONS OF LEAD ARE TYPICALLY ASSOCIATED WITH
SALVAGE ACTIVITIES. LEAD AT THE TENTH STREET SITE IS MOST LIKELY A RESULT OF AUTOMOBILE AND
OTHER METAL SALVAGE DECOMPOSITION AND CORROSION.
BASED ON THE RESULTS OF SOIL SAMPLING, IT IS ESTIMATED THAT APPROXIMATELY 7,500 CU. YARDS OF
SOIL CONTAMINATED WITH PCBS GREATER THAN 25 PPM ARE PRESENT AT THE SITE. OF THIS VOLUME, 6,500
CU. YARDS ARE CONTAMINATED WITH GREATER THAN 300 PPM PCBS, REPRESENTING THE VOLUME OF MATERIAL
THAT POSES THE PRINCIPAL THREAT AT THIS SITE. PRINCIPAL THREATS ARE DEFINED AS SOIL
CONTAMINATED AN ORDER OF MAGNITUDE OR MORE ABOVE THE HEALTH-BASED GOAL SET FOR THE SITE. SOIL
CONTAMINATED BETWEEN 25 PPM AND 300 PPM (1,000 YDS.) REPRESENTS THE LOW-LEVEL THREAT POSED BY
THE TENTH STREET SITE.
GROUNDWATER
GROUNDWATER SAMPLES WERE COLLECTED FROM THE FIVE MONITORING WELLS INSTALLED DURING THE RI AND
FROM ONE EXISTING PRIVATE WELL. LOCATIONS OF GROUNDWATER SAMPLES ARE SHOWN IN FIGURE 8. PCBS
OR COMPOUNDS THAT MAY ACT AS CARRIERS FOR PCBS WERE NOT DETECTED IN GROUNDWATER SAMPLES
COLLECTED (TABLES 9 AND 10).
THE GROUNDWATER TABLE AT THE SITE RANGES FROM ABOUT 1151.7 MSL (MEAN SEA LEVEL) TO ABOUT 1150.0
MSL. CONTAMINATED SOIL AT ITS DEEPEST POINT ONSITE IS APPROXIMATELY 3 FEET ABOVE THE WATER
TABLE. THE GROUNDWATER WAS MEASURED IN APRIL 1989, A MONTH IN WHICH GROUNDWATER LEVELS ARE
CONSIDERED TO BE HIGH IN OKLAHOMA.
SURFACEWATER
SURFACEWATER SAMPLES WERE COLLECTED FROM A TRIBUTARY THAT RUNS BY THE WESTERN MARGIN OF THE SITE
AND FROM THE NORTH CANADIAN RIVER (FIGURE 9). CONTAMINANTS ATTRIBUTABLE TO THE SITE WERE NOT
DETECTED IN THE SURFACEWATER SAMPLES COLLECTED (TABLE 9 AND 11). THIS CONCLUSION IS BASED ON
UPSTREAM SAMPLES BEING EQUALLY OR MORE CONTAMINATED THAN DOWNSTREAM SAMPLES.
MIGRATION PATHWAYS
THE CONTAMINANTS OF CONCERN AT THIS SITE ARE PCBS. THE MIGRATION OF PCBS IN THE SUBSURFACE (IN
SOIL, SOIL TO GROUNDWATER, AND IN GROUNDWATER) IS CONTROLLED BY SEVERAL FACTORS. THESE INCLUDE
THE SOLUBILITY OF PCBS, SOIL PERMEABILITY, THE PRESENCE OR ABSENCE OF TRANSPORT-FACILITATING
SOLVENTS, ORGANIC CARBON CONTENT, AND ORGANIC COLLOIDS. WITH THE VERY LOW SOLUBILITY OF PCBS,
THE PRESENCE OF A PROTECTIVE CAP, THE ABSENCE OF TRANSPORT-FACILITATING SOLVENTS, NORMAL ORGANIC
CARBON CONTENT, NO DETECTION OF PCBS ADHERING TO COLLOIDS, AS WELL AS THE PHYSICAL SEPARATION
BETWEEN CONTAMINATED SOIL AND THE GROUNDWATER TABLE, IT WOULD TAKE FREE PRODUCT TO BE PRESENT AT
THE SITE IN ORDER FOR SUBSURFACE MIGRATION TO OCCUR. PCBS ARE FIXED IN THE SOIL MATRIX BENEATH
THE TENTH STREET SITE AND MIGRATION IS NOT OCCURRING.
AT PRESENT TIME, AIRBORNE MIGRATION OF PCBS FROM THE SITE IS NOT LIKELY. WITH THE PROTECTIVE
SOIL COVER AND VEGETATION ESTABLISHED, ANY MIGRATION OF CONTAMINANTS BY PARTICULATES GENERATED
FROM WIND EROSION IS VIRTUALLY ELIMINATED. THE POTENTIAL FOR AIRBORNE MIGRATION OF PCBS FROM
THE SITE WOULD EXIST, ONLY IF THE SOIL COVER IS DESTROYED BY EXTERNAL FORCES SUCH AS HEAVY
EROSION, FLOODING, OR PHYSICAL DESTRUCTION. LIKEWISE, THE CURRENT POTENTIAL FOR TRANSPORT OF
PCBS FROM THE SITE VIA SURFACEWATER IS MINIMAL DUE TO THE EXISTENCE OF THE PROTECTIVE COVER.
IF THE PCB CONTAMINATED SOIL WAS EXPOSED, THE AREAS MOST LIKELY TO BE IMPACTED BY CONTAMINANT
MIGRATION WOULD BE THE NEARBY COMMUNITY AND PERSONS WHO VISIT THE AUTOMOBILE JUNK YARD.
#SSR
VI. SUMMARY OF SITE RISKS
A BASELINE RISK ASSESSMENT WAS CONDUCTED FOR THIS SITE AND IS PRESENTED IN A DOCUMENT ENTITLED,
BASELINE RISK ASSESSMENT FOR THE TENTH STREET DUMP SUPERFUND SITE, OKLAHOMA CITY, OKLAHOMA. THE
ASSESSMENT FOLLOWS PROCEDURES SET IN THE EPA RISK ASSESSMENT GUIDANCE FOR SUPERFUND SITES,
DECEMBER 1989.
IDENTIFICATION OF CONTAMINANTS OF CONCERN
CHEMICALS WHOSE ANALYTICAL RESULTS ARE OF ACCEPTABLE QUALITY FOR USE IN THE RISK ASSESSMENT AND
RELATED TO THE SITE WERE IDENTIFIED AS CONTAMINANTS OF CONCERN FOR THIS SITE. CONCENTRATIONS OF
SITE-RELATED CONTAMINANTS IN WATER AND SOIL SAMPLES ARE COMPARED TO APPLICABLE OR RELEVANT AND
APPROPRIATE REQUIREMENTS (ARARS). IN ADDITION, COMPARISONS ARE MADE TO LOCAL AND NATIONAL
BACKGROUND CONDITIONS. CHEMICALS WHOSE CONCENTRATIONS ARE LESS THAN BACKGROUND ARE ELIMINATED
FROM THE QUANTITATIVE RISK ASSESSMENT. CHEMICALS DETECTED AT THE SITE AND THEIR COMPARISON TO
ARARS AND BACKGROUND LEVELS ARE ALSO SUMMARIZED IN TABLES 5, 10, AND 11.
EXPOSURE ASSESSMENT
IN THE RISK ASSESSMENT, EPA EVALUATED THE CURRENT, OR BASELINE, RISK TO HEALTH POSED BY THE
CONTAMINANTS AT THE TENTH STREET SITE. SINCE THE SITE IS CURRENTLY UNOCCUPIED, ASSUMPTIONS
REGARDING THE MOST PROBABLE FUTURE LAND USE FOR THE SITE WERE MADE BY EPA. BECAUSE THE
PROPERTIES SURROUNDING THE SITE ARE OPERATING AUTOMOBILE SALVAGE YARDS AND INQUIRIES HAVE BEEN
MADE OF EPA REGARDING THE SUITABILITY OF THE SITE FOR FUTURE DEVELOPMENT, EPA CONSIDERED THE
PROBABLE FUTURE LAND USE TO BE COMMERCIAL.
THE RISK
ASSESSMENT AND THE DEVELOPMENT OF REMEDIAL GOALS FOCUSED ON THE EFFECTS WORKERS EXPOSED TO THE
SITE CONTAMINANTS.
THE ASSUMPTIONS USED FOR THE GROUNDWATER INGESTION SCENARIO ARE:
1. 70-YEAR LIFETIME;
2. 70 KG. (ADULT) AND 10 KG. (CHILD) BODY WEIGHT;
3. INGESTION RATE OF 2 LITERS PER DAY FOR ADULTS;
4. INGESTION RATE OF 1 LITER PER DAY FOR CHILDREN.
THE ASSUMPTIONS USED FOR SOIL INGESTION AND DERMAL ABSORPTION WERE BASED ON AN INDUSTRIAL/
COMMERCIAL EXPOSURE SCENARIO:
1. 70-YEAR LIFETIME;
2. 70 KG. BODY WEIGHT;
3. INGESTION RATE OF 0.1 GRAMS PER DAY;
4. EXPOSURE DURATION OF 9 YEARS, 40 HOURS PER DAY, FIVE DAYS PER WEEK.
THESE ASSUMPTIONS ARE STANDARDIZED IN THE RISK ASSESSMENT GUIDANCE.
TOXICITY ASSESSMENT
QUANTITATIVE RISK ASSESSMENT REQUIRES CONTAMINANT-SPECIFIC QUALITATIVE AND QUANTITATIVE TOXICITY
INFORMATION. CONTAMINANTS ARE CLASSIFIED AS SYSTEMIC TOXICANTS, AND/OR AS KNOWN OR SUSPECTED
HUMAN CARCINOGENS. FOR SYSTEMIC TOXICANTS, THE EPA REFERENCE DOSES (RFDS) AND, ACCEPTABLE
INTAKES SUBCHRONIC AND CHRONIC (AISS AND AICS) ARE IDENTIFIED. FOR KNOWN OR SUSPECTED
CARCINOGENS, EPA WEIGHT-OF EVIDENCE CLASSIFICATIONS AND UPPER BOUND CANCER SLOPE FACTORS ARE
IDENTIFIED. INCLUDED IN THE RISK ASSESSMENT ARE PERTINENT STANDARDS, CRITERIA AND GUIDELINES
DEVELOPED FOR THE PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT. DOSE-RESPONSE PARAMETERS USED
IN THE ASSESSMENT ARE PRESENTED BELOW.
ORGANIC CHEMICALS
ACETONE. THE CHRONIC ORAL RFD FOR ACETONE IS 0.1 MG/KG/DAY (HEALTH EFFECTS ASSESSMENT SUMMARY
TABLES, THIRD QUARTER FY 1989. (HEAST).
BENZENE. THE CHRONIC ORAL RFD FOR BENZENE IS 7E-4 MG/KG/DAY (0.0007) (ATSDR 1987). BENZENE IS
CLASSIFIED AS A HUMAN CARCINOGEN (GROUP A), AND HAS AN ORAL AND INHALATION SLOPE FACTOR OF
2.9E-2 (MG/KG/DAY)-1 (IRIS AND HEAST). SOME INDIVIDUALS EXPOSED TO BENZENE OVER A LONG PERIOD
OF TIME HAVE DEVELOPED LEUKEMIA (CANCER OF THE WHITE-BLOOD-CELLFORMING TISSUE) (ATSDR 1987).
BIS (2-ETHYLHEXYL) PHTHALATE. THE CHRONIC ORAL RFD FOR BIS (2 ETHYL HEXYL) PHTHALATE IS 2E-2
MG/KG/DAY (INTEGRATED RISK INFORMATION SYSTEM (IRIS) AND HEAST). IT IS CLASSIFIED AS A PROBABLE
HUMAN CARCINOGEN (GROUP B2) AND HAS AN ORAL SLOPE FACTOR OF 1.4E-2 (MG/KG/DAY)-1 (HEAST).
CARBON DISULFIDE. THE CHRONIC ORAL RFD FOR CARBON DISULFIDE IS 0.1 MG/KG/DAY (IRIS).
CHLOROFORM. THE SUBCHRONIC AND CHRONIC ORAL RFD FOR CHLOROFORM IS 1E-2 MG/KG/DAY (HEAST AND
IRIS). CHLOROFORM IS CLASSIFIED AS A PROBABLE HUMAN CARCINOGEN (GROUP B2), AND HAS ORAL AND
INHALATION SLOPE FACTORS OF 6.1E-3 AND 8.1E-2 (MG/KG/DAY) -1, RESPECTIVELY (IRIS).
CHLOROMETHANE. CHLOROMETHANE IS CLASSIFIED AS A POSSIBLE HUMAN CARCINOGEN (GROUP C), AND HAS
ORAL AND INHALATION SLOPE FACTORS OF 1.3E-2 AND 6.3E-3 (MG/KG/DAY)-1, RESPECTIVELY (HEAST).
1,4 -DICHLOROBENZENE. THE SUBCHRONIC AND CHRONIC INHALATION RFD FOR 1,4 -DICHLOROBENZENE IS 0.7
MG/CU.M (HEAST). 1,4 DICHLOROBENZENE IS CONSIDERED AS A PROBABLE HUMAN CARCINOGEN (GROUP B2)
AND HAS AN ORAL SLOPE FACTOR OF 2.4E-2 (MG/KG/DAY)-1 (HEAST).
DICHLORODIPHENYLTRICHLOROETHANE (DDT). THE SUBCHRONIC AND CHRONIC RFD FOR DDT IS 5E-4 MG/KG/DAY
(HEAST). DDT IS CLASSIFIED AS A PROBABLE HUMAN CARCINOGEN (GROUP B2), AND HAS AN ORAL AND
INHALATION SLOPE FACTOR OF 0.34 (MG/KG/DAY)-1 (HEAST).
DI-N-BUTYL PHTHALATE. SUBCHRONIC AND CHRONIC RFDS FOR DI-NBUTYL PHTHALATE ARE 1.0 AND 0.1
MG/KG/DAY, RESPECTIVELY (HEAST).
POLYCHLORINATED BIPHENYLS (PCBS). PCBS ARE A COMPLEX MIXTURE OF POLYCHLORINATED COMPOUNDS WHICH
INCLUDES AROCLORS 1242, 1254 AND 1260. THE CHRONIC ORAL RFD FOR PCBS IS BASED ON A STUDY USING
AROCLOR 1016 (NO DATA ON NONCARCINOGIC EFFECTS OF AROCLOR 1260) AND IS 1E-4 MG/KG/DAY (ATSDR).
PCBS ARE CLASSIFIED AS A PROBABLE HUMAN CARCINOGEN WITH A SLOPE FACTOR OF 7.7 (MG/KG/DAY)-1.
POLYNUCLEAR AROMATIC HYDROCARBONS (PAHS). PAHS ARE A COMPLEX CLASS OF COMPOUNDS WHICH INCLUDES:
ACENAPHTHENE, ANTHRACENE, BENZO (A) ANTHRACENE, BENZO (A) PYRENE, BENZO (B) FLUORANTHENE, BENZO
(G,H,I) PERYLENE, BENZO(K) FLUORANTHENE, CHRYSENE, DIBENZ (A,H) ANTHRACENE, FLUORENE,
FLUORANTHENE, INDENO (1,2,3 CD) PYRENE, PHENANTHRENE AND PYRENE. THE SUBCHRONIC AND CHRONIC
ORAL RFD FOR PAHS IS BASED ON THE TOXICITY OF NAPHTHALENE AND IS 0.4 MG/KG/DAY. PAHS ARE
CLASSIFIED AS PROBABLE HUMAN CARCINOGENS (GROUP B2), AND HAVE ORAL AND INHALATION SLOPE FACTORS
OF 11.5 AND 6.1 (MG/KG DAY)-1, RESPECTIVELY (EPA 1986). PAH SLOPE FACTORS ARE BASED ON BENZO
(A) PYRENE CARCINOGENICITY. THE FOLLOWING PAHS ARE CONSIDERED TO BE CARCINOGENIC:
BENZO(A)ANTHRACENE, BENZO (A) PYRENE, BENZO (B) FLUORANTHENE, BENZO (G,H,I) PERYLENE, BENZO (K)
FLUORANTHENE, CHRYSENE, DIBENZO(A,H)PERYLENE, BENZO(K)FLUORANTHENE, DIBENZO (A,H) ANTHRACENE AND
INDENO (1,2,3, CD) PYRENE.
TETRACHLOROETHYLENE (PERCHLOROETHYLENE). THE SUBCHRONIC AND CHRONIC RFDS FOR
TETRACHLOROETHYLENE ARE 0.1 AND 0.01 MG/KG/DAY, RESPECTIVELY (HEAST). TETRACHLOROETHYLENE IS
CLASSIFIED AS A PROBABLE HUMAN CARCINOGEN (B2), AND HAS AN ORAL AND INHALATION SLOPE FACTORS OF
5.1E-2 AND 3.3E-3 (MG/KG/DAY)-1, RESPECTIVELY (HEAST).
TOLUENE. THE SUBCHRONIC AND CHRONIC ORAL RFDS FOR TOLUENE ARE 4E-1 AND 3E-1 MG/KG/DAY,
RESPECTIVELY (IRIS AND HEAST). SUBCHRONIC AND CHRONIC INHALATION RFD FOR TOLUENE IS 2 MG/CU.M
(HEAST). THE EPA DETERMINATION OF TOLUENE CARCINOGENICITY IS PENDING (IRIS).
1,2,4-TRICHLOROBENZENE. THE SUBCHRONIC AND CHRONIC ORAL RFDS FOR 1,2,4TRICHLOROBENZENE ARE 2E-1
AND 2E-2 MG/KG/DAY, RESPECTIVELY; SUBCHRONIC AND CHRONIC INHALATION RFDS ARE 3E-2 AND 3E-3
MG/KG/DAY, RESPECTIVELY (HEAST).
1,1,1-TRICHLOROETHANE. THE SUBCHRONIC AND CHRONIC ORAL RFDS FOR 1,1,1TRICHLOROETHANE ARE 9E-1
AND 9E-2 MG/KG/DAY, RESPECTIVELY; AND THE SUBCHRONIC AND CHRONIC INHALATION RFDS ARE 10 AND 1
MG/CU.M (IRIS AND HEAST). THE EPA DETERMINATION OF ITS CARCINOGENICITY IS PENDING (IRIS).
XYLENE. FOR MIXED XYLENES, SUBCHRONIC AND CHRONIC ORAL RFDS ARE 4E PLUS
0 AND 2.0 MG/KG/DAY, RESPECTIVELY; AND THE CHRONIC INHALATION RFD IS
3E-1 MG/CU.M. (HEAST).
INORGANIC CHEMICALS
ALUMINUM. THE DATA ON ALUMINUM IS INADEQUATE FOR QUANTITATIVE RISK ASSESSMENT (HEAST).
ANTIMONY. THE SUBCHRONIC AND CHRONIC ORAL RFD FOR ANTIMONY IS 4E-4 (MG/KG/DAY) (IRIS AND
HEAST).
ARSENIC. THE SUBCHRONIC AND CHRONIC ORAL RFD FOR ARSENIC IS 1E-3 MG/KG/DAY (HEAST). ARSENIC IS
CLASSIFIED AS A HUMAN CARCINOGEN (GROUP A), AND HAS ORAL AND INHALATION SLOPE FACTORS OF 1.8 AND
1.5E PLUS 1 (MG/KG/DAY)-1 (IRIS).
BARIUM. FOR BARIUM, THE SUBCHRONIC AND CHRONIC ORAL RFD IS 5E-2 MG/KG/DAY (IRIS AND HEAST);
SUBCHRONIC AND CHRONIC INHALATION RFDS ARE 5E-3 AND 5E-4 MG/KG/DAY, RESPECTIVELY (HEAST).
BERYLLIUM. THE SUBCHRONIC AND CHRONIC ORAL RFD FOR BERYLLIUM IS 5E-3 (MG/KG/DAY) - 1 (HEAST).
CADMIUM. THE CHRONIC RFDS FOR CADMIUM ARE 1E-3 MG/KG/DAY (FOOD) AND 5E-4 MG/KG/DAY (WATER)
(HEAST). CADMIUM IS CONSIDERED AS A PROBABLE HUMAN CARCINOGEN BY INHALATION (GROUP B1) AND HAS
AN INHALATION SLOPE FACTOR OF 6.1E PLUS 0 (MG/KG/DAY)-1 (IRIS AND HEAST).
CHROMIUM. THE CHRONIC RFD FOR CHROMIUM IS 5E-3 MG/KG/DAY (IRIS). CHROMIUM IS CONSIDERED AS A
HUMAN CARCINOGEN BY INHALATION (GROUP A) AND HAS AN INHALATION SLOPE FACTOR OF 4.1E PLUS 1
(MG/KG/DAY)-1 (IRIS).
COBALT. QUANTITATIVE RISK ASSESSMENT INFORMATION ON COBALT IS NOT AVAILABLE.
COPPER. FOR COPPER, THE ORAL AIS AND AIC IS 3.7E-2 MG/KG/DAY AND THE INHALATION AIC IS 1E-2
MG/KG/DAY (EPA 1986). COPPER IS NOT CLASSIFIED AS TO HUMAN CARCINOGENICITY (GROUP D) (IRIS).
CYANIDE. THE SUBCHRONIC AND CHRONIC ORAL RFD FOR CYANIDE IS 2E-2
MG/KG/DAY (HEAST).
LEAD. LEAD CAN HAVE PROFOUND ADVERSE EFFECTS ON CERTAIN BLOOD ENZYMES AND ON ASPECTS OF
CHILDREN'S NEUROBEHAVIORAL DEVELOPMENT. THESE ADVERSE EFFECTS MAY OCCUR AT BLOOD LEAD LEVELS SO
LOW AS TO BE ESSENTIALLY WITHOUT A THRESHOLD (IRIS). FOR LEAD, ORAL AIC IS 1.4E-3 MG/KG/DAY AND
INHALATION AIC IS 4.3E-4 MG/KG/DAY (EPA 1986). LEAD IS CLASSIFIED AS A PROBABLEHUMAN CARCINOGEN
(GROUP B2) (IRIS AND HEAST).
MANGANESE. FOR MANGANESE, THE SUBCHRONIC AND CHRONIC ORAL RFDS ARE 5E-1 AND 2E-1 MG/KG/DAY,
RESPECTIVELY; AND THE SUBCHRONIC AND CHRONIC INHALATION RFD IS 3E-4 (HEAST). MANGANESE IS NOT
CLASSIFIED AS TO HUMAN CARCINOGENICITY (GROUP D) (IRIS).
MERCURY. THE SUBCHRONIC AND CHRONIC ORAL RFD ALKYL AND INORGANIC MERCURY IS 3E-4 MG/KG/DAY
(HEAST).
NICKEL. THE SUBCHRONIC AND CHRONIC ORAL RFD FOR NICKEL IS 2E-2 MG/KG/DAY (HEAST). NICKEL IS
CLASSIFIED AS A HUMAN CARCINOGEN BY INHALATION (GROUP A) AND HAS AN INHALATION SLOPE FACTOR OF
8.4E-1 (MG/KG/DAY) -1 (IRIS).
SELENIUM. FOR SELENIUM, THE SUBCHRONIC AND CHRONIC ORAL RFDS ARE 4E-3 AND 3E-3 MG/KG/DAY,
RESPECTIVELY; AND THE SUBCHRONIC AND CHRONIC INHALATION RFD IS 1E-3 MG/KG/DAY (HEAST).
SILVER. THE ORAL AIC FOR SILVER IS 3E-3 MG/KG/DAY (EPA 1986).
VANADIUM. THE SUBCHRONIC AND CHRONIC RFD FOR VANADIUM IS 7E-3 MG/KG/DAY (HEAST).
ZINC. THE SUBCHRONIC AND CHRONIC RFD FOR ZINC IS 0.2 MG/KG/DAY (HEAST).
RISK CHARACTERIZATION
THE FIRST STEP IN THE RISK CHARACTERIZATION IS TO CALCULATE THE INTAKE OF SPECIFIC SITE-RELATED
CONTAMINANTS ABSORBED FROM THE AFFECTED MEDIA. INTAKES BY EXPOSED POPULATIONS WILL BE CALCULATED
FOR THE SELECTED PATHWAYS OF EXPOSURE, AND CONVERTED TO DAILY DOSES (IN MG/KG BODY WEIGHT/DAY)
BY CORRECTING FOR ABSORPTION EFFICIENCY ACROSS GASTROINTESTINAL, PULMONARY, OR DERMAL
BOUNDARIES. THESE DOSES ARE DENOTED BY EPA AS THE CHRONIC DAILY INTAKE (CDI). THE CDIS FOR
SYSTEMIC (NONCARCINOGENIC) AND CARCINOGENIC HEALTH EFFECTS ARE CALCULATED SEPARATELY TO ACCOUNT
FOR DIFFERENCES IN THE AVERAGING TIME.
THE POTENTIAL EFFECTS OF CONTAMINANTS ON HUMAN HEALTH HAVE BEEN EVALUATED FOR THEIR
NONCARCINOGENIC AND CARCINOGENIC EFFECTS. FOR NONCARCINOGENIC EFFECTS, A CHRONIC HAZARD INDEX
(HI) IS CALCULATED BY SUMMING THE QUOTIENTS OF THE CONTAMINANT-SPECIFIC CDIS BY THE CONTAMINANT
SPECIFIC RFDS OR AICS. A TOTAL (I.E, ACCOUNTING FOR ALL MEDIA) HI GREATER THAN 1 SUGGESTS A
POTENTIAL HUMAN HEALTH CONCERN. FOR GROUNDWATER EXPOSURE, THE EVALUATION OF NONCARCINOGENIC
EFFECTS WILL FOCUS ON 1 TO 6 YEAR OLD CHILDREN, WHO ARE THE MOST SENSITIVE TO CONTAMINANT
EXPOSURES.
FOR CARCINOGENIC EFFECTS, THE POTENTIAL UPPER-BOUND LIFETIME EXCESS CANCER RISK (ACCOUNTING FOR
ALL CONTAMINATED MEDIA) IS ESTIMATED BY SUMMING THE PRODUCTS OF THE CONTAMINANT-SPECIFIC CDIS
AND THE CONTAMINANT-SPECIFIC SLOPE FACTORS. EPA CONSIDERS A LIFETIME UPPER BOUND OF RISK RANGE
OF (10-4) TO (10-6) AS THE TARGET RANGE FOR REMEDIAL ACTION GOALS AT SUPERFUND SITES. EPA ALSO
CONSIDERS THE 1E-6 RISK LEVEL AS THE "POINT OF DEPARTURE" FOR REMEDIAL GOALS. THIS IS THE LEVEL
THAT THE AGENCY EXPECTS TO ACHIEVE WHERE PRACTICABLE.
THE DERMAL ABSORPTION ROUTE LACKS THE TOXICITY REFERENCE VALUES OF THE OTHER EXPOSURE ROUTES
(E.G., ORAL AND INHALATION), ORAL VALUES WERE USED TO ASSESS RISKS FROM DERMAL EXPOSURE.
THE RESULTS OF THE RISK ASSESSMENT INDICATE THAT NO ADVERSE HEALTH EFFECTS WOULD BE EXPECTED
FROM INGESTION OF THE GROUNDWATER NEAR THE SITE. PCBS WERE NOT DETECTED IN ANY GROUNDWATER
SAMPLES TAKEN. DATA PRESENTED IN TABLE 2 INDICATES THAT THE MAXIMUM CONCENTRATION LIMITS FOR
METALS WERE NOT EXCEEDED IN ANY SAMPLES TAKEN.
THE RISK ASSESSMENT ALSO INDICATED THAT NON-CARCINOGENIC RISKS FROM PCBS, METALS, POLYNUCLEAR
AROMATIC HYDROCARBONS, AND SOLVENTS ARE NOT PRESENT AT THIS SITE. THE COMBINED HAZARD INDEX,
THE MEASURE OF NON-CARCINOGENICITY, FOR DIRECT CONTACT WITH THE CONTAMINATED SOIL WAS CALCULATED
TO BE 0.55. A HAZARD INDEX OF 1.0 OR GREATER IS CONSIDERED BY EPA TO REPRESENT A
NON-CARCINOGENIC RISK.
CARCINOGENIC RISKS POSED BY THE SITE ARE ATTRIBUTED TO THE PCB CONTAMINATION IN THE SOIL. THE
AVERAGE LIFETIME CARCINOGENIC RISK FROM DIRECT CONTACT WITH THE SOIL, BASED ON THE AVERAGE
CONCENTRATION OF PCBS IN THE SOIL, IS ESTIMATED TO BE 3.8 X (10-5) EXCESS CANCER INCIDENTS.
UNDER THE "WORST CASE" CONDITIONS, THE ESTIMATED RISK IS 9.6 X (10-5), OR APPROXIMATELY 1 X
(10-4). POLYNUCLEAR AROMATIC HYDROCARBONS, METALS, AND SOLVENTS DID NOT CONTRIBUTE TO THE
CARCINOGENIC RISKS (LESS THAN (10-6) RISK).
ENVIRONMENTAL ASSESSMENT
THE ENVIRONMENTAL RISKS ASSOCIATED WITH CONTAMINANTS AT THE SITE APPEAR TO BE NON-MEASURABLE OR
MINIMAL. SURFACEWATER SAMPLES COLLECTED SHOW NO ORGANIC CHEMICALS RELATED TO THE SITE AND
SIMILAR CONCENTRATIONS OF INORGANIC CHEMICALS. BIOTA SAMPLES COLLECTED INDICATE THAT THE NORTH
CANADIAN RIVER, DOWNSTREAM FROM THE SITE CONTAIN MORE INDIVIDUALS AND SPECIES THAN UPSTREAM.
THE VEGETATION IN THE VICINITY OF THE SITE AND COTTONWOOD TREES ALONG THE INTERMITTENT STREAM
WEST OF THE SITE DID NOT APPEAR TO BE STRESSED. DURING 1987, THE US FISH AND WILDLIFE SERVICE
OF THE DEPARTMENT OF THE INTERIOR CONDUCTED A PRELIMINARY NATURAL RESOURCE SURVEY AND GRANTED A
RELEASE FROM NATURAL RESOURCE DAMAGES.
#DA
VII. DESCRIPTION OF ALTERNATIVES
AS DISCUSSED EARLIER, PCBS ARE THE CONTAMINANTS OF CONCERN AND ARE LIMITED TO SURFACE AND
SUBSURFACE SOILS AT THE SITE. REMEDIAL ALTERNATIVES FOR THE TENTH STREET SITE HAVE BEEN
EVALUATED WITH RESPECT TO NINE EVALUATION CRITERIA SET IN THE NATIONAL CONTINGENCY PLAN, THE
TOXIC SUBSTANCE CONTROL ACT (TSCA), PCB REGULATIONS; THE RESOURCE CONSERVATION AND RECOVERY ACT
(RCRA), LAND DISPOSAL RESTRICTIONS; THE OKLAHOMA SOLID WASTE MANAGEMENT ACT, REGULATIONS
GOVERNING SOLID WASTE AND SLUDGE MANAGEMENT. THE PCB SPILL CLEANUP POLICY, WHICH IS NOT AN ARAR
BUT IS CODIFIED IN THE FEDERAL REGISTER, HAS ALSO BEEN CONSIDERED. THE TSCA PCB REGULATIONS OF
IMPORTANCE TO SUPERFUND SITES ARE FOUND IN 40 CFR PART 761, SUBPART D: STORAGE AND DISPOSAL
(761.60 - 761.79). THESE REGULATIONS SPECIFY THE TREATMENT AND DISPOSAL REQUIREMENTS FOR PCBS.
RCRA LAND DISPOSAL RESTRICTIONS DO NOT SPECIFICALLY APPLY TO PCB CONTAMINATION, AS PCBS ALONE
ARE NOT A RCRA WASTE. HOWEVER, IF THE PCBS ARE MIXED WITH OTHER HAZARDOUS WASTE(S), THEY MAY BE
SUBJECT TO LAND DISPOSAL RESTRICTIONS. THE OKLAHOMA REGULATIONS GOVERNING SOLID WASTE AND
SLUDGE MANAGEMENT SPECIFY LANDFILL LOCATION STANDARDS, AND THE FINAL COVER REQUIREMENT. UNDER
EPA GUIDANCE ON REMEDIAL ACTIONS FOR SUPERFUND SITES WITH PCB CONTAMINATION (AUGUST 1990), LAND
USE (RESIDENTIAL, INDUSTRIAL, OR RURAL) IS A PRIMARY CONSIDERATION IN DETERMINING CLEANUP LEVEL.
THE CONCENTRATION OF PCBS THAT CAN BE LEFT IN THE SOIL ON SITE DEPENDS PRIMARILY ON THE EXPECTED
EXPOSURE SCENARIO (I.E. DIRECT CONTACT, LIMITED CONTACT, OR RESTRICTED CONTACT THROUGH CAPPING
AND ACCESS CONTROL) AND THE ACHIEVEMENT OF ADEQUATE RISK PROTECTION.
REMEDIAL ACTION IS CLEARLY WARRANTED AT TENTH STREET BASED ON THE AUGUST 1990 EPA GUIDANCE FOR
PCB-CONTAMINATED SUPERFUND SITES. SECTION 3.1.2 OF THIS GUIDANCE DISCUSSES REMEDIAL GOALS FOR
INDUSTRIAL OR REMOTE AREAS WITH PCB CONTAMINATION. A RANGE OF 10 PPM TO 25 PPM IS CONSIDERED
APPROPRIATE FOR A REMEDIAL GOAL IN AN INDUSTRIAL AREA. THIS GOAL IS CONSISTENT WITH THE GOALS
SET IN THE TSCA SPILL CLEANUP POLICY.
THE REMEDIAL GOAL FOR THE TENTH STREET SITE WAS SET BASED ON FUTURE INDUSTRIAL LAND USE AND IS
25 PPM PCBS IN THE SOIL ONSITE. THIS GOAL WAS SELECTED TO BE CONSISTENT WITH THE TOXIC
SUBSTANCES CONTROL ACT SPILL CLEANUP POLICY CRITERIA FOR COMMERCIAL/INDUSTRIAL AREAS AND GOALS
SET AT OTHER SUPERFUND SITES NATIONWIDE WHERE COMMERCIAL EXPOSURES WERE CONSIDERED. THIS
CONCENTRATION ALSO REPRESENTS A MAXIMUM RESIDUAL EXCESS CANCER RISK OF 1 X (10-5). THIS RISK IS
BASED ON A FUTURE COMMERCIAL/INDUSTRIAL LAND USE. AN ESTIMATED 7,500 CUBIC YARDS OF SOIL TO A
DEPTH OF ABOUT 6 FEET ARE CONTAMINATED WITH GREATER THAN 25 PPM OF PCBS AND WILL BE ADDRESSED BY
THE REMEDIAL ACTION.
ALTERNATIVES EVALUATION
TO ACHIEVE THE REMEDIAL GOAL, TECHNOLOGIES AND PROCESS OPTIONS APPLICABLE TO THIS SITE WERE
IDENTIFIED AND ANALYZED. AFTER THE SCREENING PROCESS, A TOTAL OF SIX ALTERNATIVES WERE
FORMULATED. THESE ALTERNATIVES WERE FURTHER EVALUATED IN TERMS OF EFFECTIVENESS,
IMPLEMENTABILITY, AND COST.
FIVE ALTERNATIVES WERE ANALYZED IN DETAIL IN THE FS. THESE FIVE ALTERNATIVES ARE LISTED BELOW
AND NUMBERED TO CORRESPOND WITH THE ALTERNATIVES IN THE FS REPORT.
• ALTERNATIVE 1: NO ACTION
• ALTERNATIVE 3: EXCAVATION AND OFFSITE DISPOSAL
• ALTERNATIVE 4: EXCAVATION, ONSITE CHEMICAL TREATMENT AND DISPOSAL ONSITE
• ALTERNATIVE 5: EXCAVATION, ONSITE THERMAL TREATMENT, AND DISPOSAL ONSITE
• ALTERNATIVE 6: EXCAVATION AND OFFSITE THERMAL TREATMENT
ALTERNATIVE 2, IN PLACE CAPPING WAS SCREENED OUT PRIOR TO THE DETAILED EVALUATION OF
ALTERNATIVES BECAUSE THE SITE IS IN A FLOOD PLAIN AND BECAUSE CAPPING WOULD NOT SATISFY THE
PREFERENCE FOR TREATMENT EXPRESSED IN SARA.
EXCEPT FOR THE "NO ACTION" ALTERNATIVE, ALL OF THE ALTERNATIVES CONSIDERED FOR THE SITE INCLUDE
A COMMON COMPONENT, THE REMOVAL AND/OR TREATMENT OF PCB CONTAMINATED SOIL. AN AIR MONITORING
PROGRAM AND DUST CONTROL MEASURES WOULD BE IMPLEMENTED TO REDUCE/MINIMIZE ANY POTENTIAL ADVERSE
SHORT-TERM HEALTH EFFECTS DURING EXCAVATION AND TREATMENT ACTIVITIES. INSTITUTIONAL CONTROLS
WOULD NOT BE REQUIRED FOR ANY OF THE ALTERNATIVES, EXCEPT THE "NO ACTION" ALTERNATIVE.
DESCRIPTIONS OF EACH OF THE ALTERNATIVES ARE AS FOLLOWS:
ALTERNATIVE 1: NO ACTION
• ESTIMATED CAPITAL COST: $2,500
• ESTIMATED ANNUAL O&M COSTS: $11,800
• ESTIMATED TOTAL PRESENT WORTH COSTS: $184,200
• ESTIMATED IMPLEMENTATION TIMEFRAME: 30 YEARS FOR O&M
THE SUPERFUND REGULATIONS (NATIONAL CONTINGENCY PLAN) REQUIRES THAT THE "NO ACTION" ALTERNATIVE
BE EVALUATED AT EVERY SITE TO ESTABLISH A BASELINE FOR COMPARISON. NO CONSTRUCTION ACTIVITIES
WOULD OCCUR AT THE SITE; AN ESTIMATED 7,500 CU. YD. OF PCB CONTAMINATED SOIL AT CONCENTRATIONS
OF 25 PPM AND ABOVE WOULD REMAIN AT THE SITE.
UNDER THIS ALTERNATIVE, DEED RESTRICTIONS TO PROHIBIT SOIL EXCAVATION AND CONSTRUCTION
ACTIVITIES WOULD BE IMPOSED ON THE SITE, AND REGULAR MAINTENANCE INCLUDING VEGETATION MOWING,
RESEEDING, AND FENCE AND COVER SURFACE REPAIR WOULD BE PERFORMED. THE TWO DOWNGRADIENT
GROUNDWATER MONITORING WELLS WOULD BE SAMPLED AND ANALYZED FOR PCBS ANNUALLY TO ENSURE THAT NO
MIGRATION OF PCBS TO GROUNDWATER UNDERNEATH THE SITE OCCURS. THIS ALTERNATIVE WOULD MEET NEITHER
THE TOXIC SUBSTANCES CONTROL ACT (TSCA) PCB DISPOSAL REQUIREMENTS, PCB SPILL CLEANUP POLICY, NOR
THE OKLAHOMA SOLID WASTE REGULATIONS. THIS ALTERNATIVE WOULD NOT MITIGATE THE LONG-TERM RISKS
IDENTIFIED WITH THE CONTAMINANTS AT THE SITE.
BECAUSE THIS ALTERNATIVE WOULD RESULT IN CONTAMINANTS REMAINING AT THE SITE, CERCLA REQUIRES
THAT THE SITE BE REVIEWED EVERY FIVE YEARS.
ALTERNATIVE 3: EXCAVATION AND OFFSITE DISPOSAL
• ESTIMATED CAPITAL COSTS: $4,037,000
• ESTIMATED ANNUAL 0&M COSTS: $0.00
• ESTIMATED TOTAL PRESENT WORTH COSTS: $4,037,000
• ESTIMATED IMPLEMENTATION TIMEFRAME: 3 MONTHS
THIS ALTERNATIVE CONSISTS OF THE REMOVAL OF THE EXISTING TEMPORARY RED CLAY COVER AND EXCAVATION
AND DISPOSAL OF THE PCB-CONTAMINATED SOIL IN A TSCA-PERMITTED CHEMICAL LANDFILL. THE RED CLAY
REMOVED COULD BE RETAINED TO SUPPLEMENT THE CLEAN SOIL REQUIRED TO BACKFILL THE EXCAVATED AREA.
THE CONTAMINATED SOIL WOULD BE EXCAVATED AND TEMPORARILY STORED IN WASTE PILES. THE
CONTAMINATED SOIL WOULD THEN BE LOADED ONTO 20 CU. YD. DUMP TRUCKS FOR TRANSPORT TO A
TSCA-PERMITTED LANDFILL. PRIOR TO LEAVING THE SITE, THE TRUCKS WOULD BE INSPECTED TO ENSURE
HAZARDOUS SUBSTANCE TRANSPORTATION REQUIREMENTS ARE MET. MANIFESTS WOULD ALSO BE PREPARED AND
SIGNED AS REQUIRED. THE EXCAVATED AREA WOULD BE BACKFILLED WITH CLEAN SOIL. THE FINAL SURFACE
WOULD BE GRADED AND SEEDED TO BLEND WITH THE SURROUNDING AREA.
UNDER THIS ALTERNATIVE, AN ESTIMATED 7,500 CU. YD. OF PCB CONTAMINATED SOIL AT CONCENTRATIONS OF
25 PPM AND ABOVE WOULD BE REMOVED FROM THE SITE. DURING IMPLEMENTATION OF THIS ALTERNATIVE,
MEASURES TO SUPPRESS DUST GENERATED DURING EXCAVATION WILL BE USED TO MITIGATE ANY POTENTIAL
RISK TO THE NEARBY COMMUNITY MAY BE EXPECTED DUE TO FUGITIVE DUSTS IN THE AMBIENT AIR. AFTER
COMPLETION OF THIS ALTERNATIVE, NO LONG-TERM MONITORING AND MAINTENANCE WOULD BE REQUIRED AND
THE SITE RISK WOULD BE REDUCED TO (10-6). THIS ALTERNATIVE WOULD MEET THE TSCA PCB DISPOSAL
REQUIREMENTS AND THE PCB SPILL CLEANUP POLICY.
ALTERNATIVE 4: EXCAVATION, ONSITE CHEMICAL TREATMENT, AND DISPOSAL ONSITE
• ESTIMATED CAPITAL COSTS: $4,044,000
• ESTIMATED ANNUAL O&M COSTS: $0.00
• ESTIMATED TOTAL PRESENT WORTH COSTS: $4,044,000
• ESTIMATED IMPLEMENTATION TIMEFRAME: 6-9 MONTHS
THIS ALTERNATIVE CONSISTS OF REMOVING THE EXISTING RED CLAY COVER AND TREATING THE PCB
CONTAMINATED SOIL ON-SITE BY A CHEMICAL PROCESS TO DESTROY CHLORINATED BIPHENYLS.
AFTER TREATMENT, THE TREATED SOIL (LESS THAN 2 PPM PCB) WOULD BE PUT BACK INTO THE EXCAVATED
AREA. THE CLAY COVER COULD BE RETAINED AND USED AS CLEAN BACKFILL MATERIAL. IF NEEDED,
ADDITIONAL CLEAN SOIL WOULD BE BROUGHT TO THE SITE FOR FINAL GRADING.
THE BASICS OF THE CHEMICAL DECHLORINATION PROCESS ARE STRAIGHT FORWARD. CONTAMINATED SOIL IS
MIXED WITH AN ALKALINE REAGENT CONSISTING OF POTASSIUM OR SODIUM HYDROXIDE IN A SOLUTION OF
MIXED POLYETHYLENE GLYCOL AND DIMETHYL SULFOXIDE. THE REAGENT MIXTURE DECHLORINATES THE ARYL
HALIDE TO FORM A PEG ETHER AND A TOTALLY DECHLORINATED SPECIES.
IN SOIL PROCESSING, THE SOIL/REAGENT MIXTURE IS HEATED TO 30 - 150 C WITH MIXING UNTIL THE
REACTION HAS BEEN COMPLETED. AT THE END OF THE REACTION, REAGENT IS RECOVERED BY DECANTATION
AND WASHING THE SOIL WITH SEVERAL VOLUMES OF WATER. THE DECONTAMINATED SOIL IS THEN DISCHARGED,
WITH THE REAGENT RECYCLED FOR REUSE. WATER VAPOR AND VOLATILES GENERATED DURING THE PROCESS
WILL PASS THROUGH A CONDENSOR EQUIPPED WITH A CARBON ADSORPTION FILTER BEFORE DISCHARGING TO A
WASTE TREATMENT UNIT. ANY VOLATILES THAT ARE NOT CONDENSED WILL BE TRAPPED BY THE FILTER.
SPENT CARBON FILTERS WILL BE HANDLED IN ACCORDANCE WITH THE WASTE CLASSIFICATION. CHEMICAL
ANALYSIS WILL BE PERFORMED TO ENSURE THAT DISCHARGED SOIL IS CLEAN.
A TREATABILITY STUDY CONDUCTED DURING THE RI INDICATED THE KPEG TREATMENT PROCESS TO BE A
FEASIBLE AND EFFECTIVE TECHNOLOGY FOR DECONTAMINATING PCB CONTAMINATED SOIL AT THIS SITE. THIS
STUDY DEMONSTRATED THAT THIS TECHNOLOGY CAN DESTROY PCB CONTAMINATION AT THIS SITE TO BELOW 1
PPM IN THE SOIL.
AN ESTIMATED 7,500 CU. YD. OF PCB CONTAMINATED SOIL WITH CONCENTRATIONS OF 25 PPM AND ABOVE
WOULD BE TREATED. THE CONCENTRATIONS OF THE TREATED RESIDUAL WOULD BE REDUCED TO LESS THAN 2
PPM. DURING IMPLEMENTATION OF THIS ALTERNATIVE, DUST SUPPRESSION AND MONITORING WILL BE DONE TO
MITIGATE ANY RISK FROM FUGITIVE DUSTS THAT MAY BE GENERATED. EMISSIONS FROM THE TREATMENT
PROCESS WOULD BE MINIMAL, WATER VAPOR AND VOLATILES GENERATED WHICH ARE NOT REMOVED BY THE
CONDENSOR UNIT WOULD UNIT WOULD BE TRAPPED BY CARBON ADSORPTION. COMPLETION OF THIS ALTERNATIVE
WOULD REDUCE THE SITE RISK TO (10-6) AND NO LONG-TERM MONITORING AND MAINTENANCE WOULD BE
REQUIRED. THIS ALTERNATIVE WOULD MEET THE TSCA PCB ALTERNATIVE TREATMENT REQUIREMENTS (2.0 PPM)
AND THE PCB SPILL CLEANUP POLICY.
ALTERNATIVE 5: EXCAVATION, ONSITE THERMAL TREATMENT, AND DISPOSAL ONSITE
• ESTIMATED CAPITAL COST: $4,406,000
• ESTIMATED ANNUAL O&M COSTS: $0.00
• ESTIMATED TOTAL PRESENT WORTH COSTS: $4,406,000
• ESTIMATED IMPLEMENTATION TIMEFRAME: 6-9 MONTHS
THIS ALTERNATIVE CONSISTS OF REMOVING THE EXISTING RED CLAY COVER AND TREATING THE PCB
CONTAMINATED SOIL ON-SITE BY AN INCINERATOR MEETING THE INCINERATION DESTRUCTION REMOVAL
EFFICIENCY (DRE) OF 99.9999 PERCENT SET FOR PCBS BY REGULATION. AFTER TREATMENT, THE TREATED
SOIL WOULD PUT BACK INTO THE EXCAVATED AREA. THE CLAY COVER COULD BE RETAINED AND USED AS CLEAN
BACKFILL MATERIAL. ADDITIONAL CLEAN SOIL, IF NEEDED, WOULD BE PLACED ON TOP OF THE SITE FOR
FINAL GRADING.
PRIOR TO INCINERATION, CONTAMINATED SOIL WOULD BE EXCAVATED AND STORED TEMPORARILY IN WASTE
PILES. THE CONTAMINATED SOIL WOULD BE FED INTO THE ONSITE INCINERATOR EQUIPPED WITH EMISSION
CONTROLS AND ASH HANDLING EQUIPMENT. THE EXHAUST GASES RESULTING FROM INCINERATION WOULD BE
SCRUBBED BEFORE VENTING TO THE ATMOSPHERE.
THE SCRUBBER WATER WOULD BE INCINERATED OR TREATED BY PASSING THROUGH SERIAL ACTIVATED CARBON
COLUMNS. THE SPENT CARBON WOULD BE INCINERATED. THE ASH WOULD BE TESTED PRIOR TO BACKFILLING
THE EXCAVATED AREA TO ENSURE PCBS ARE DESTROYED. A SHREDDER WOULD BE USED TO REDUCE LUMPS OF
CLAY, ROCKS, AND OTHER LARGE DEBRIS TO AN ACCEPTABLE SIZE FOR INCINERATION. LARGE PIECES OF
DEBRIS, SUCH AS BRICKS, ROCKS, OR CONCRETE FOUND DURING THE EXCAVATION THAT CAN NOT BE SHREDDED
WOULD BE ASSUMED PCB WASTES AND DISPOSED OF IN AN APPROVED LANDFILL.
AN ESTIMATED 7,500 CU. YD. OF PCB CONTAMINATED SOIL AT CONCENTRATIONS OF 25 PPM AND ABOVE WOULD
BE TREATED BY THE MOBILE INCINERATOR BROUGHT ONSITE. AFTER INCINERATION, THE SITE RISK WOULD BE
REDUCED TO 1E-6. NO LONG-TERM MONITORING AND MAINTENANCE WOULD BE REQUIRED. ANY INCREASE IN
RISK BY INHALATION DUE TO THE INTRODUCTION OF FUGITIVE DUSTS IN ATMOSPHERE BY SOIL EXCAVATION
WOULD BE SIMILAR TO ALTERNATIVE 3. A POTENTIAL INCREASE IN RISK BY INHALATION TO THE NEARBY
COMMUNITY WOULD ALSO EXIST, IF EMISSION CONTROL SYSTEM OF THE INCINERATOR WERE TO FAIL. THIS
ALTERNATIVE WOULD MEET THE TSCA PCB INCINERATION REQUIREMENTS (40 CFR 761), THE PCB SPILL
CLEANUP POLICY, AND THE OKLAHOMA CLEAN AIR ACT.
ALTERNATIVE 6: EXCAVATION AND OFFSITE THERMAL TREATMENT
• ESTIMATED CAPITAL COSTS: $17,829,000
• ESTIMATED ANNUAL O&M COSTS: $0.00
• ESTIMATED TOTAL PRESENT WORTH COSTS: $17,829,000
• ESTIMATED IMPLEMENTATION TIMEFRAME: 3 MONTHS
THIS ALTERNATIVE CONSISTS OF REMOVING THE EXISTING RED CLAY COVER AND TRANSPORTING THE PCB
CONTAMINATED SOIL TO A PERMITTED INCINERATION FACILITY OFF-SITE. THE PCB WOULD BE THERMALLY
DESTROYED AT THE OFF-SITE FACILITY. THE COVER SOIL REMOVED COULD BE RETAINED TO SUPPLEMENT THE
CLEAN SOIL REQUIRED TO BACKFILL THE EXCAVATED AREA AND FOR FINAL GRADING.
THE CONTAMINATED SOIL WOULD BE EXCAVATED AND TEMPORARILY STORED IN WASTE PILES READY FOR LOADING
AND TRANSPORTATION. THE CONTAMINATED SOIL WOULD THEN BE LOADED ONTO 20 CU. YD. DUMP TRUCKS.
PRIOR TO LEAVING THE SITE, THE TRUCKS WOULD BE INSPECTED TO ENSURE HAZARDOUS SUBSTANCE
TRANSPORTATION REQUIREMENTS ARE MET. MANIFESTS WOULD ALSO BE PREPARED AND SIGNED AS REQUIRED.
THE EXCAVATED AREA WOULD BE BACKFILLED WITH CLEAN SOIL. THE FINAL SURFACE WOULD BE GRADED AND
SEEDED TO BLEND WITH THE SURROUNDING AREA.
IMPLEMENTATION OF THIS ALTERNATIVE WOULD REMOVE AN ESTIMATED 7,500 CU. YD. OF PCB CONTAMINATED
SOIL AT CONCENTRATIONS OF 25 PPM AND ABOVE FROM THE SITE AND REDUCE THE SITE RISK TO 1E-6. NO
LONG-TERM MONITORING AND MAINTENANCE WOULD BE REQUIRED. DURING SOIL EXCAVATION, STOCKPILING,
AND LOADING, THIS ALTERNATIVE WOULD HAVE A POTENTIAL FOR TEMPORARY INCREASES IN RISK BY
INHALATION TO THE NEARBY COMMUNITY SIMILAR TO ALTERNATIVE 3. THIS ALTERNATIVE WOULD MEET THE
TSCA PCB INCINERATION REQUIREMENTS AND THE PCB SPILL CLEANUP POLICY.
#SCAA
VIII. SUMMARY OF THE COMPARATIVE ANALYSIS OF ALTERNATIVES
OVERALL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
ALL OF THE ALTERNATIVES, WITH THE EXCEPTION OF THE "NO ACTION" ALTERNATIVE, WOULD BE COMPARABLE
IN TERMS OF PROVIDING ADEQUATE PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT. THEY ACHIEVE
PROTECTION BY ELIMINATING, REDUCING, OR CONTROLLING RISKS THROUGH SOURCE REMOVAL AND TREATMENT.
AT THE CLEANUP LEVEL OF 25 PPM, RISKS THROUGH DIRECT CONTACT AND INGESTION ARE REDUCED TO A
CANCER RISK MAXIMUM LEVEL OF (10-5). THE OVERALL AVERAGE SITE RISK OF (10-6) IS ACHIEVED BY
TREATMENT OR REMOVAL OF THE CONTAMINATED SOIL AND THE PLACEMENT OF TREATED SOIL ON THE SITE.
ALTERNATIVE 4, 5, AND 6 ACHIEVE PROTECTION BY REDUCING EXPOSURE THROUGH TREATMENT. ALTERNATIVE 3
REDUCES RISKS BY SOURCE REMOVAL. UNDER THE "NO ACTION" ALTERNATIVE, AS LONG AS THE INTEGRITY OF
THE EXISTING SOIL COVER IS MAINTAINED, NO IMMINENT AND SUBSTANTIAL ENDANGERMENT TO PUBLIC
HEALTH, WELFARE, OR THE ENVIRONMENT WOULD BE EXPECTED. HOWEVER, CONTAMINATION WILL REMAIN AT
THE SITE AND POTENTIAL FOR CONTAMINANT MIGRATION WILL ALWAYS EXIST. ALSO, SITE ACCESS WOULD BE
RESTRICTED AND NO EXCAVATIONS OR CONSTRUCTION ACTIVITIES WOULD BE PERMITTED AT THE SITE.
COMPLIANCE WITH ARARS
ALL OF THE ALTERNATIVES, WITH THE EXCEPTION OF THE "NO ACTION" ALTERNATIVE, WILL ACHIEVE THE 25
PPM REMEDIAL GOAL SET IN THE TSCA SPILL CLEANUP POLICY. THE USE OF A FULLY COMPLIANT LAND
DISPOSAL FACILITY PERMITTED TO ACCEPT PCB-CONTAMINATED MATERIALS WILL ENSURE THAT ALTERNATIVE 2,
OFFSITE LAND DISPOSAL, MEETS THE TSCA DISPOSAL REGULATIONS (40 CFR 761.75). CHEMICAL
DECHLORINATION WILL ACHIEVE THE 2.0 PPM CONCENTRATION SET IN THE TSCA ALTERNATE TECHNOLOGY
REGULATIONS. BOTH ONSITE AND OFFSITE THERMAL DESTRUCTION ALTERNATIVES WOULD COMPLY WITH THE
INCINERATOR REGULATIONS GOVERNING PCB DISPOSAL (40 CFR 761.70).
LONG-TERM EFFECTIVENESS AND PERMANENCE
ALTERNATIVE 4,5, AND 6 AFFORD THE HIGHEST DEGREES OF LONG-TERM EFFECTIVENESS AND PERMANENCE AS
THEY USE TREATMENT TECHNOLOGIES TO REDUCE HAZARDOUS POSED BY CONTAMINATION AT THIS SITE.
ALTERNATIVE 4 USES A CHEMICAL TREATMENT TECHNOLOGY WHILE ALTERNATIVES 5 AND 6 USE THERMAL
DESTRUCTION. BOTH CHEMICAL DECHLORINATION AND INCINERATION ARE IRREVERSIBLE PROCESSES.
ALTERNATIVE 3 WOULD PROVIDE THE SIMILAR LEVEL OF PROTECTION FOR THIS SITE THROUGH SOURCE
REMOVAL. HOWEVER, THE WASTE WOULD NOT BE DESTROYED, IT WOULD SIMPLY BE RELOCATED TO ANOTHER
SITE. AT 25 PPM, THE AVERAGE RISKS FROM THE SITE WOULD BE REDUCED TO 10-6 BY ALTERNATIVES 3, 4,
5, AND 6.
ALTERNATIVE 1 LEAVES ALL OF THE CONTAMINATED SOIL AT THE SITE AND RELIES ENTIRELY UPON THE
EXISTING SOIL COVER. AS THE EXISTING SOIL COVER WAS NOT CONSTRUCTED TO MEET THE RCRA CAP
REQUIREMENTS, NOR TO MEET THE OKLAHOMA SOLID WASTE REGULATIONS FINAL COVER REQUIREMENTS,
LONG-TERM EFFECTIVENESS AND PERMANENCE OF THE EXISTING SOIL COVER IS QUESTIONABLE.
REDUCTION OF TOXICITY, MOBILITY, OR VOLUME
ALTERNATIVES 4, 5, AND 6 WOULD TREAT THE CONTAMINATED SOIL TO REDUCE THE TOXICITY, MOBILITY AND
VOLUME OF CONTAMINATION AT THE SITE. AT A CLEANUP LEVEL OF 25 PPM, APPROXIMATELY 7,500 CU. YD.
OF PCB CONTAMINATED SOIL WOULD BE TREATED. ABOUT 1,000 CU.YDS. OF SOIL WITH PCB CONCENTRATIONS
OF 25 PPM AND BELOW WOULD REMAIN AT THE SITE. ALTERNATIVE 4 WOULD TREAT THE CONTAMINATED SOIL
CHEMICALLY AND REDUCE THE CONCENTRATIONS OF CONTAMINANT TO LESS THAN 2 PPM. ALTERNATIVES 5 AND
6 WOULD INVOLVE INCINERATION PROCESSES THAT WOULD HAVE A DRE OF 99.9999 PERCENT.
ALTERNATIVE 3, REMOVAL OF THE SOURCE OF CONTAMINATION AND DISPOSAL IN A CHEMICAL WASTE LANDFILL,
WOULD SIMPLY TRANSFER THE CONTAMINATION FROM ONE SITE TO ANOTHER AND WOULD NOT REDUCE THE
TOXICITY OR VOLUME OF THE CONTAMINATION. ALTERNATIVE 1 WILL NOT REDUCE TOXICITY, MOBILITY, OR
VOLUME OF THE CONTAMINATION.
SHORT-TERM EFFECTIVENESS
ALTERNATIVE 3, 4, 5, AND 6 ARE ANTICIPATED TO POSE SIMILAR LEVELS OF SHORT-TERM RISKS. HOWEVER,
ALTERNATIVE 4 WOULD PROVIDE THE GREATEST SHORT-TERM EFFECTIVENESS AND PRESENT THE LEAST AMOUNT
OF RISK TO WORKERS, THE COMMUNITY, AND THE ENVIRONMENT.
PARTICULATE EMISSIONS RESULTING FROM EXCAVATION AND STOCKPILING OF CONTAMINATED SOIL WOULD BE
EXPECTED DURING IMPLEMENTATION OF ALTERNATIVE 4. EMISSIONS GENERATED FROM KPEG TREATMENT
PROCESS WOULD BE KEPT AT MINIMUM. WATER VAPOR AND VOLATILES GENERATED IN THE REACTOR WILL GO
THROUGH A CONDENSOR EQUIPPED WITH A CARBON ADSORPTION FILTER BEFORE DISCHARGING INTO A WASTE
TREATMENT UNIT. ANY VOLATILES THAT ARE NOT CONDENSED WILL BE TRAPPED BY THE FILTER. SPENT
CARBON WILL BE HANDLED IN ACCORDANCE WITH THE WASTE CLASSIFICATION. THE REAGENTS AND BYPRODUCTS
USED IN THE CHEMICAL DECHLORINATION PROCESS WILL NOT POSE ANY SHORT TERM RISKS. DATA GENERATED
IN LABORATORY TESTS USING RATS INDICATES THAT ETHYLENE GLYCOLATE-400 IS 27 TIMES LESS TOXIC THAN
PCBS; DIMETHYL SULFOXIDE IS 17 TIMES LESS TOXIC THAN PCBS. THESE REAGENTS ARE ALSO 9 AND 6
TIMES, RESPECTIVELY, LESS TOXIC THAN TABLE SALT. THE RESULTS OF AMES TOXICITY TESTS INDICATES
THAT THE BYPRODUCTS OF THE DECHLORINATION PROCESS DO NOT EXHIBIT ANY CARCINOGENIC POTENTIAL.
ALTERNATIVES 3 AND 6 ARE VERY SIMILAR WITH RESPECT TO SHORT-TERM EFFECTIVENESS. IN ADDITION TO
PARTICULATE EMISSIONS RESULTING FROM EXCAVATION OF CONTAMINATED SOIL, POTENTIAL RELEASE OF
CONTAMINANTS ALONG THE ROUTE OF TRANSPORTATION WOULD EXIST, IF AN ACCIDENT WERE TO OCCUR.
ALTERNATIVES 4 AND 5 CAN BE IMPLEMENTED IN APPROXIMATELY 6 TO 9 MONTHS. ALTERNATIVES 3 AND 6 CAN
BE COMPLETED IN APPROXIMATELY 3 MONTHS.
IMPLEMENTABILITY
ALTERNATIVES 1, 3, AND 6 WOULD BE THE SIMPLEST TO CONDUCT AND OPERATE. NO SPECIAL TECHNIQUES,
MATERIALS, PERMITS, OR LABOR WOULD BE REQUIRED FOR IMPLEMENTATION OF THESE ALTERNATIVES; THEY
ARE READILY AVAILABLE IN THE LOCAL AREA. PERMITTED PCB LANDFILLS AND OFFSITE PCB INCINERATORS
ARE COMMERCIALLY AVAILABLE.
ALTERNATIVE 4, THE KPEG TREATMENT PROCESS, IS MORE COMPLEX THAN ALTERNATIVES 3 AND 6. IT WOULD
REQUIRE SPECIALISTS TO CONSTRUCT AND OPERATE THE SYSTEM. PILOT TESTING WOULD BE REQUIRED TO
DETERMINE OPERATING PARAMETERS AND FINE TUNE THE OPERATION. DURING OPERATION, THIS TREATMENT
PROCESS WOULD REQUIRE CONSTANT ATTENTION AND PERIODIC ADJUSTMENT.
ALTERNATIVE 5 IS PROBABLY THE MOST COMPLEX ALTERNATIVE TO OPERATE. DESPITE ANTICIPATED DOWNTIME
DUE TO MECHANICAL COMPLEXITY, INCINERATION COULD RELIABLY MEET THE DRE. A MOBILE INCINERATOR
WOULD HAVE TO BE BROUGHT ONSITE. THIS ALTERNATIVE WOULD REQUIRE THE MOST ATTENTION AS
INCINERATION REQUIRES PERIODIC SAMPLING OF THE RESIDUE AND MODIFICATION OF OPERATING PARAMETERS.
A TEST BURN WOULD BE REQUIRED TO DETERMINE THE OPERATING PARAMETERS. MOBILE INCINERATORS ARE
COMMERCIALLY AVAILABLE FROM NUMEROUS VENDORS.
COST
ALTERNATIVE 1 HAS THE LOWEST ESTIMATED PRESENT WORTH COST, $184,200. THE COST FOR ALTERNATIVE 3
IS ESTIMATED AT $4,037,000. ALTERNATIVE 4 HAS AN ESTIMATED COST SIMILAR TO ALTERNATIVE 3,
$4,044,000. THE ESTIMATED COST FOR ALTERNATIVE 5 IS $4,0406,000, WHICH IS ABOUT 10 PERCENT
HIGHER THAN ALTERNATIVE 4. ALTERNATIVE 6 HAS THE HIGHEST ESTIMATED COST, $17,829,000.00, WHICH
IS ABOUT 4.5 TIMES HIGHER THAN ALTERNATIVE 4.
STATE ACCEPTANCE
THE STATE OF OKLAHOMA CURRENTLY PREFERS THE "NO ACTION" ALTERNATIVE. THE STATE BELIEVES THAT
BECAUSE THE BASELINE RISK (10-4) IS WITHIN THE REMEDIAL TARGET RANGE ESTABLISHED IN THE NATIONAL
CONTINGENCY PLAN (10-4) TO (10-6) THAT FURTHER ACTION IS NOT WARRANTED AT THE SITE. THE STATE
ALSO BELIEVES THAT THE SHORT-TERM RISKS OF IMPLEMENTATION OF A REMEDY ARE GREATER THAN THE
LONG-TERM RISKS CURRENTLY POSED BY THE SITE, ALTHOUGH THE STATE DID NOT OFFER ANY QUANTITATIVE
EVIDENCE TO SUBSTANTIATE THE BELIEF.
COMMUNITY ACCEPTANCE
COMMUNITY RESPONSE TO THE ALTERNATIVES IS DISCUSSED IN THE RESPONSIVENESS SUMMARY, WHICH
ADDRESSES COMMENTS RECEIVED DURING THE PUBLIC COMMENT PERIOD. CITIZENS RAISED QUESTIONS ABOUT
EXPOSURE TO FUGITIVE DUST FROM EXCAVATION, OTHER LOCATIONS WHERE THE TECHNOLOGY HAS BEEN USED,
AND THE POSSIBILITY OF LOCAL CONTRACTORS IMPLEMENTING THE REMEDY.
#SR
IX. THE SELECTED REMEDY
BASED UPON CONSIDERATION OF THE REQUIREMENTS OF CERCLA, THE DETAILED ANALYSIS OF THE
ALTERNATIVES, AND PUBLIC COMMENTS, THE US EPA HAS SELECTED ALTERNATIVE 4 - EXCAVATION, ONSITE
CHEMICAL TREATMENT, AND DISPOSAL ONSITE AS THE REMEDY FOR THE TENTH STREET SUPERFUND SITE.
SOIL SAMPLE ANALYSES OBTAINED DURING RI INDICATE THAT THE ESTIMATED VOLUME OF PCB CONTAMINATED
SOIL AT THE SITE IS APPROXIMATELY 8,500 CU. YD. BASED ON THE FUTURE INDUSTRIAL LAND USE AND
COMPLIANCE WITH THE TSCA SPILL CLEANUP POLICY, THE REMEDIAL GOAL IS SET AT 25 PPM. AT THIS
CLEANUP TARGET, THE INCREASED CANCER RISK POSED BY THE SITE WOULD BE REDUCED TO (10-5).
AN ESTIMATED 7,500 CU. YD. OF SOIL CONTAMINATED WITH GREATER THAN 25 PPM PCBS WOULD BE EXCAVATED
AND TREATED ONSITE BY CHEMICAL DECHLORINATION TREATMENT UNIT. THE TREATED SOIL WOULD CONTAIN
LESS THAN 2 PPM OF PCB. A TREATABILITY STUDY CONDUCTED DURING RI HAS DEMONSTRATED THAT THE KPEG
TREATMENT PROCESS IS CAPABLE OF DESTROYING PCB CONTAMINATION AT THIS SITE TO BELOW 1 PPM.
#SD
X. STATUTORY DETERMINATIONS
UNDER ITS LEGAL AUTHORITIES, EPA'S PRIMARY RESPONSIBILITY AT SUPERFUND SITES IS TO UNDER TAKE
REMEDIAL ACTIONS THAT ACHIEVE ADEQUATE PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT. IN
ADDITION, SECTION 121 OF CERCLA ESTABLISHED SEVERAL OTHER STATUTORY REQUIREMENTS AND
PREFERENCES. THESE SPECIFY THAT WHEN COMPLETE, THE SELECTED REMEDY FOR THIS SITE MUST COMPLY
WITH APPLICABLE OR RELEVANT AND APPROPRIATE ENVIRONMENTAL STANDARDS ESTABLISHED UNDER FEDERAL
AND STATE ENVIRONMENTAL LAWS UNLESS A STATUTORY WAIVER IS JUSTIFIED.
THE SELECTED REMEDY ALSO MUST BE COST EFFECTIVE AND UTILIZE PERMANENT SOLUTIONS AND ALTERNATIVE
TREATMENT TECHNOLOGIES OR RESOURCE RECOVERY TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE.
FINALLY, THE STATUTE INCLUDES A PREFERENCE FOR REMEDIES THAT USE TECHNOLOGIES THAT PERMANENTLY
AND SIGNIFICANTLY REDUCE THE VOLUME, TOXICITY, OR MOBILITY OF HAZARDOUS WASTES AS THEIR
PRINCIPAL ELEMENT. THE FOLLOWING SECTIONS DISCUSS HOW THE SELECTED REMEDY MEETS THESE STATUTORY
REQUIREMENTS.
PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT
THE SELECTED REMEDY PROTECTS HUMAN HEALTH AND THE ENVIRONMENT THROUGH TREATMENT OF THE PCB
CONTAMINATED SOIL. THE CONTAMINANT WILL BE PERMANENTLY REMOVED FROM THE SOIL BY GLYCOLATE
DEHALOGENATION PROCESS. THE TREATMENT PROCESS WILL DEGRADE THE PCBS INTO LESS TOXIC, WATER
SOLUBLE COMPOUNDS (GLYCOL-ETHERS AND CHLORIDE SALTS), WHICH FURTHER DEGRADE TO FORM A TOTALLY
DECHLORINATED SPECIES.
DESTRUCTION OF PCBS FROM THE SOIL AND BACKFILLING THE TREATED SOIL, IN THE EXCAVATED AREA WOULD
REDUCE THE EXCESS CANCER RISK POSED BY THE SITE TO (10-6). BECAUSE THE CHEMICAL DECHLORINATION
PROCESS EQUIPMENT IS COMPLETELY ENCLOSED, THERE ARE NO SHORT-TERM THREATS ASSOCIATED WITH
MATERIALS HANDLING WITH THE SELECTED REMEDY.
COMPLIANCE WITH APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS
THE SELECTED REMEDY OF EXCAVATION, ONSITE CHEMICAL TREATMENT, AND DISPOSAL OF TREATED SOIL WILL
COMPLY WITH ALL APPLICABLE OR RELEVANT AND APPROPRIATE REQUIREMENTS (ARARS). THE ARARS ARE
PRESENTED BELOW.
ACTION-SPECIFIC ARARS:
• PCB ALTERNATIVE TREATMENT REQUIREMENTS (2 PPM PCBS) PCBS, USING TOTAL WASTE ANALYSIS
(40 CFR PART 761, SUBPART D)
OTHER CRITERIA, ADVISORIES OR GUIDANCE TO BE CONSIDERED:
• TSCA PCB SPILL CLEANUP POLICY (FEDERAL REGISTER, APRIL 2, 1990)
• EPA GUIDANCE ON SELECTING REMEDIES FOR SUPERFUND SITES WITH PCB CONTAMINATION
(AUGUST 1990)
LAND DISPOSAL RESTRICTIONS UNDER RCRA ARE NOT ARARS FOR THE PCB CONTAMINATED SOILS AT THIS SITE.
COST - EFFECTIVENESS
THE SELECTED REMEDY IS COST-EFFECTIVE, AS IT HAS BEEN DETERMINED TO PROVIDE A HIGH DEGREE OF
EFFECTIVENESS PROPORTIONAL TO ITS COST. THE ESTIMATED TOTAL PRESENT WORTH VALUE IS $4,044,000.
THE SELECTED REMEDY IS THE LEAST COSTLY OF THE ALTERNATIVES 4, 5, AND 6 WHICH ARE EQUALLY
PROTECTIVE OF HUMAN HEALTH AND THE ENVIRONMENT.
UTILIZATION OF PERMANENT SOLUTIONS AND ALTERNATIVE TREATMENT TECHNOLOGIES OR RESOURCE RECOVERY
TECHNOLOGIES TO THE MAXIMUM EXTENT PRACTICABLE
US EPA HAS DETERMINED THAT 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 TENTH STREET SUPERFUND SITE. OF THOSE ALTERNATIVES THAT ARE PROTECTIVE OF HUMAN
HEALTH AND THE ENVIRONMENT AND COMPLY WITH ARARS, EPA HAS 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, COSTS, ALSO CONSIDERING THE STATUTORY PREFERENCE FOR TREATMENT AS A PRINCIPAL
ELEMENT AND CONSIDERING STATE AND COMMUNITY INPUT. ALTERNATIVE 1 WOULD NOT REDUCE THE TOXICITY,
MOBILITY OR VOLUME OF THE CONTAMINATION; WOULD NOT COMPLY WITH ARARS; WOULD NOT PROVIDE RELIABLE
LONG-TERM EFFECTIVENESS; WOULD PROVIDE SHORT-TERM EFFECTIVENESS; WOULD TAKE 30 YEARS TO
IMPLEMENT. CONTAMINATION WILL REMAIN AT THE SITE AND POTENTIAL FOR CONTAMINANT MIGRATION WILL
ALWAYS EXIST.
ALTERNATIVE 3 WOULD PROTECT HUMAN HEALTH AND THE ENVIRONMENT FOR THIS SITE ABOUT EQUALLY AS WELL
AS THE SELECTED REMEDY. IT WOULD ALSO HAVE SIMILAR LONG-TERM EFFECTIVENESS, AND SHORT-TERM
EFFECTIVENESS. HOWEVER, ALTERNATIVE 3 WOULD NOT REDUCE THE TOXICITY OR VOLUME OF THE
CONTAMINANT, IT WOULD SIMPLY RELOCATE THE CONTAMINATION TO ANOTHER SITE. ALTERNATIVES 5 AND 6
WOULD PROVIDE EQUAL PROTECTION OF HUMAN HEALTH AND THE ENVIRONMENT AND LONG-TERM EFFECTIVENESS
AS THE SELECTED REMEDY. THEY WOULD ALSO HAVE THE SAME LEVEL OF REDUCTION IN TOXICITY, MOBILITY,
AND VOLUME AS THE SELECTED REMEDY. HOWEVER, ALTERNATIVES 5 AND 6 WOULD HAVE HIGHER COSTS AND
LESS SHORT-TERM EFFECTIVENESS.
PRINCIPAL THREATS AT TENTH STREET ARE DEFINED AS THOSE SOILS CONTAMINATED WITH GREATER THAN 300
PPM PCBS, AN ORDER OF MAGNITUDE HIGHER THAN THE HEALTH BASED REMEDIAL GOAL. LOW LEVEL THREATS
ARE THOSE SOILS WITH LESS THAN 300 PPM PCBS. THE NCP EXPECTS THAT PRINCIPAL THREATS WILL BE
TREATED; LOW LEVEL THREATS WILL ALSO BE TREATED WHERE COST-EFFECTIVE.
CONTAINMENT OF THE LOW LEVEL THREATS WAS NOT CONSIDERED BECAUSE THE COST OF TREATING ALL SOILS
ABOVE THE HEALTH-BASED REMEDIAL GOAL IS ONLY APPROXIMATELY 10 PERCENT OF THE COST OF TREATING
THE HIGH LEVEL THREATS. THEREFORE, EPA CONSIDERS TREATMENT OF ALL SOIL CONTAMINATED WITH GREATER
THAN 25 PPM PCBS TO BE COST-EFFECTIVE.
PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT
BY TREATING THE PCB CONTAMINATED SOIL AT THE SITE AND DISPOSING THE TREATED SOIL ONSITE, THE
SELECTED REMEDY ADDRESSES THE PRINCIPAL THREAT OF FUTURE DIRECT CONTACT/INGESTION OF
CONTAMINATED SOIL POSED BY THE SITE THROUGH THE USE OF TREATMENT TECHNOLOGIES. THEREFORE, THE
STATUTORY PREFERENCE FOR REMEDIES THAT EMPLOY TREATMENT AS A PRINCIPAL ELEMENT IS SATISFIED.
DOCUMENTATION OF NO SIGNIFICANT CHANGES
THE PROPOSED PLAN FOR THE TENTH STREET SITE WAS RELEASED FOR PUBLIC COMMENT IN AUGUST 1990. THE
PROPOSED PLAN IDENTIFIED ALTERNATIVE 4, CHEMICAL DECHLORINATION OF CONTAMINATED SOIL, AS THE
PREFERRED ALTERNATIVE.
EPA REVIEWED ALL WRITTEN AND VERBAL COMMENTS SUBMITTED DURING THE PUBLIC COMMENT PERIOD. UPON
REVIEW OF THESE COMMENTS,IT WAS DETERMINED THAT NO SIGNIFICANT CHANGES TO THE REMEDY, AS IT WAS
ORIGINALLY IDENTIFIED IN THE PROPOSED PLAN, WERE NECESSARY.
#RS
RESPONSIVENESS SUMMARY
THE COMMUNITY RELATIONS RESPONSIVENESS SUMMARY HAS BEEN PREPARED TO PROVIDE WRITTEN RESPONSES TO
COMMENTS SUBMITTED REGARDING THE PROPOSED PLAN AT THE TENTH STREET HAZARDOUS WASTE SITE. THE
SUMMARY IS DIVIDED INTO TWO SECTIONS.
SECTION I: BACKGROUND OF COMMUNITY INVOLVEMENT AND CONCERNS.
THIS SECTION PROVIDES A BRIEF HISTORY OF COMMUNITY INTEREST AND CONCERNS RAISED DURING THE
REMEDIAL PLANNING ACTIVITIES AT THE TENTH STREET SITE.
SECTION II: SUMMARY OF MAJOR COMMENTS RECEIVED:
THE COMMENTS (BOTH ORAL AND WRITTEN) ARE SUMMARIZED AND EPA'S RESPONSE ARE PROVIDED.
I: BACKGROUND OF COMMUNITY INVOLVEMENT AND CONCERNS
THE INVOLVEMENT IN ENVIOROMENTAL ISSUES, INCLUDING HAZARDOUS WASTE MANAGEMENT IS GROWING. LOCAL
CHAPTERS OF NATIONAL ENVIRONMENTAL ORGANIZATIONS AND A VARIETY OF GOVERNMENTAL GROUPS ARE
INVOLVED IN EFFORTS TO SAFEGUARD SURFACE AND GROUNDWATER RESOURCES. COMMUNITY CONCERNS ARE THAT
THE CONTAMINANTS FROM THE SITE HAVE LEACHED INTO THE AREAS GROUNDWATER. IN ADDITION TO CONCERNS
ABOUT GROUNDWATER QUALITY, MEMBERS OF THE COMMUNITY FEAR THAT BEFORE THE SITE WAS CAPPED
RAINFALL COULD HAVE WASHED HAZARDOUS WASTE FROM THE SURFACE OF THE LANDFILL, SPREADING
CONTAMINANTS BEYOND THE BOUNDARY OF THE SITE TO AFFECT OFFSITE SURFACE SOIL AND WATER THUS
MAKING THE AREA UNSAFE FOR RECREATION.
II. SUMMARY OF MAJOR COMMENTS RECEIVED
PUBLIC NOTICE ANNOUNCING THE PUBLIC COMMENT PERIOD AND OPPORTUNITY FOR A PUBLIC MEETING WAS
PRINTED IN THE DAILY OKLAHOMAN ON SUNDAY AUGUST 5, 1990. THE PROPOSED PLAN FACT SHEET WAS
DISTRIBUTED TO THE SITE MAILING LIST ON AUGUST 3, 1990. THE COMMENT PERIOD BEGAN ON AUGUST 9,
1990 AND ENDED SEPTEMBER 7, 1990. A PUBLIC MEETING WAS HELD ON AUGUST 14, 1990, AT THE JAMES
STEWART BUILDING IN OKLAHOMA CITY, OKLAHOMA. THE PURPOSE OF THIS MEETING WAS TO EXPLAIN THE
CONTAMINATION PROBLEMS AT THE SITE AND DISCUSS THE PROPOSED AND PREFERRED ALTERNATIVES.
APPROXIMATELY 20 PEOPLE WERE IN ATTENDANCE AND 11 PEOPLE ASKED QUESTIONS OR MADE COMMENTS. ONE
LETTER WAS RECEIVED WITH COMMENTS.
THE COMMENTS/QUESTIONS RECEIVED DURING THE PUBLIC COMMENT PERIOD CONCERN THE FOLLOWING:
1. COMMENT: COULD THE CHEMICALS USED IN THE CHEMICAL DECHLORINATION PROCESS BE CONDUCTED WITH
THE SOIL IN PLACE, INSTEAD OF EXCAVATING THE SOIL?
EPA RESPONSE: NO, IN PLACE DECHLORINATION WOULD NOT WORK AT THE TENTH STREET SITE. THE CLAY
SOILS ON THE SITE ARE TOO IMPERMEABLE TO ALLOW THE CHEMICALS TO MIX PROPERLY UNLESS EXCAVATION
IS DONE. WITHOUT PROPER MIXING, THE CHEMICALS WOULD NOT COME IN CONTACT WITH THE CONTAMINATED
SOILS AND PROPER DECONTAMINATION COULD NOT OCCUR. RESEARCH CONDUCTED BY EPA IN 1987 ALSO
INDICATED THAT SOILS CONTAMINATED AT DEPTHS OF GREATER THAN 2 FEET WERE NOT ADEQUATELY
DECONTAMINATED BY APPLYING THE CHEMICALS DIRECTLY TO THE SOIL. TREATMENT OF THE DEEPER
CONTAMINATED SOILS AT TENTH STREET WOULD NOT BE EFFECTIVE UNLESS EXCAVATED.
2. COMMENT: WHAT IS THE DEPTH OF CONTAMINATION AT THE TENTH STREET SITE?
EPA RESPONSE: THE SOILS AT TENTH STREET ARE CONTAMINATED WITH POLYCHLORINATED BIPHENYLS (PCBS)
TO A DEPTH OF 6 FEET. THESE SOILS ARE CONTAMINATED WITH PCBS AT CONCENTRATIONS GREATER THAN 25
PPM, THE REMEDIAL ACTION GOAL SET FOR THIS SITE.
3. COMMENT: DOES EPA CURRENTLY HAVE SPECIFICATIONS FOR THE CHEMICAL DECHLORINATION EQUIPMENT TO
BE USED AT TENTH STREET?
EPA RESPONSE: NO, THE SPECIFICATIONS FOR THIS EQUIPMENT HAVE NOT BEEN WRITTEN. WRITING THE
SPECIFICATIONS FOR REMEDIAL ACTIONS AT SUPERFUND SITES IS DONE AS PART OF THE DESIGN. HOWEVER,
THE DEVELOPMENT OF THE TECHNOLOGY IN THE FEASIBILITY STUDY WAS DONE, IN PART, BASED ON THE
SPECIFICATIONS OF EQUIPMENT CURRENTLY AVAILABLE FROM VENDORS.
4. COMMENT: WILL VENDORS WHO CURRENTLY OWN THE CHEMICAL DECHLORINATION EQUIPMENT BE THE ONLY
COMPANIES ALLOWED TO SUPPLY THE EQUIPMENT FOR THE REMEDY?
EPA RESPONSE: NO. ANY VENDOR WHO HAS THE EQUIPMENT, OR ACCESS TO THE EQUIPMENT THAT CAN
IMPLEMENT THE REMEDY WILL BE ALLOWED TO BID ON THE PROJECT. EPA, BY REGULATION (FEDERAL
ACQUISITION REGULATIONS), MUST PROVIDE FOR FAIR AND OPEN COMPETITION AMONG VENDORS WHEN
CONTRACTING FOR SUPERFUND WORK. BIDDERS MUST BE ABLE TO DEMONSTRATE THE CAPABILITY TO PERFORM
THE SPECIFIED WORK DURING THE BIDDING PROCESS WITH WHATEVER EQUIPMENT THEY HAVE AVAILABLE.
5. COMMENT: WHERE HAS CHEMICAL DECHLORINATION BEEN USED ON A FULL SCALE?
EPA RESPONSE: FULL-SCALE CHEMICAL DECHLORINATION HAS BEEN USED TO SUCCESSFULLY TREAT PCB AND
DIOXIN-CONTAMINATED MATERIALS AT THE NIAGARA-MOHAWK POWER COMPANY IN NEW YORK, THE WESTERN
PROCESSING COMPANY IN WASHINGTON, AND THE MONTANA POLE TREATING COMPANY IN MONTANA.
6. COMMENT: HOW MUCH DUST WILL BE RELEASED INTO THE AIR DURING REMEDIATION AND WHAT
PRECAUTIONS WILL BE TAKEN TO PROTECT THE COMMUNITY FROM WINDBLOWN DUST?
EPA RESPONSE: DURING EXCAVATION, WATER SPRAYS WILL BE USED TO KEEP THE SOIL WET, MINIMIZING THE
POTENTIAL FOR DUST TO BE GENERATED. THE RATE OF SOIL EXCAVATION WILL ALSO BE CORRELATED WITH THE
RATE OF TREATMENT TO MINIMIZE THE AREA OF SOIL EXPOSED TO THE WIND AT ANY GIVEN TIME. ALSO, AIR
MONITORS WILL BE PLACED AROUND THE PARAMETER OF THE SITE. THESE MONITORS WILL ALLOW THE EPA TO
DETERMINE IF WIND CONDITIONS WARRANT A SLOWER OPERATION OR TEMPORARILY CEASING OPERATIONS DUE TO
FUGITIVE DUST EMISSIONS.
7. COMMENT: WILL THERE BE AN EMERGENCY EVACUATION PLAN FOR AN EVENT WHERE EXCESSIVE DUST IS
BLOWN OFFSITE?
EPA RESPONSE: NO. IN THE EVENT THAT HIGH WINDS GENERATE EXCESSIVE DUST, AS MEASURED BY THE
AMBIENT AIR MONITORING, EXCAVATION WILL BE POSTPONED UNTIL THE WIND CONDITIONS IMPROVE AND
FUGITIVE EMISSIONS CAN BE CONTROLLED.
8. COMMENT: HOW MANY TECHNICAL ASSISTANCE GRANTS (TAGS) HAVE BEEN AWARDED IN REGION 6?
EPA RESPONSE: EPA REGION 6 AWARDED A TAG TO A COMMUNITY GROUP IN ALBUQUERQUE, NEW MEXICO FOR THE
SOUTH VALLEY SUPERFUND SITE. THIS GRANT WAS AWARDED ON FEBRUARY 23, 1990. THREE OTHER GRANTS
WERE AWARDED BY EPA TO A GROUP IN JACKSONVILLE, ARKANSAS. HOWEVER, COMPETING LOCAL GROUPS HAVE
CHALLENGED THE GRANTS AND FINAL AWARD IS PENDING THE RESOLUTION OF APPEALS.
9. COMMENT: ONE COMMENTOR REQUESTED A POSTPONEMENT OF THE PUBLIC COMMENT PERIOD UNTIL A LOCAL
COMMUNITY GROUP HAS BEEN AWARDED A TAG AND RECEIVED THE ASSISTANCE NECESSARY TO EVALUATE EPA'S
PROPOSED PLAN FOR THE TENTH STREET SITE.
EPA RESPONSE: IN A LETTER DATED SEPTEMBER 7, 1990, THIS REQUEST WAS DENIED BY EPA. IN ARRIVING
AT THIS DECISION, EPA CONSIDERED THE TIME REQUIRED BY THE GROUP TO PROCURE THE SERVICES OF AN
ADVISOR WERE THE GRANT TO BE AWARDED IN OCTOBER 1990. EPA BELIEVES THAT, SINCE THE GRANT MAY BE
USED BY THE COMMUNITY GROUP TO REVIEW THE DESIGN AND OPERATION OF THE REMEDY, A DELAY IN THE
SELECTION OF A REMEDIAL TECHNOLOGY IS NOT WARRANTED.
10. COMMENT: ONE COMMENTOR BELIEVED THAT A TAG WOULD GIVE LOCAL CITIZENS THE OPPORTUNITY TO
HIRE A CONSULTANT TO CONDUCT A REMEDIAL INVESTIGATION AND FEASIBILITY STUDY AT TENTH STREET.
EPA RESPONSE: A TAG IS NOT AVAILABLE FOR THIS PURPOSE. THIS GRANT ARE AVAILABLE FOR LOCAL
CITIZEN'S GROUPS TO REVIEW AND INTERPRET EPA'S STUDIES DURING ALL PHASES OF A SUPERFUND PROJECT.
GRANTS ARE NOT AVAILABLE FOR INDEPENDENT INVESTIGATIONS CONDUCTED BY LOCAL GROUPS.
11. COMMENT: A TAG WOULD NOT BE HELPFUL TO THE LOCAL COMMUNITY AFTER THE RECORD OF DECISION IS
SIGNED FOR THE TENTH STREET PROJECT.
EPA RESPONSE: THIS IS NOT TRUE. TAGS MAY BE USED BY THE COMMUNITY GROUP TO HIRE AN ADVISOR TO
REVIEW AND INTERPRET BOTH THE REMEDIAL DESIGN AND CONSTRUCTION ACTIVITIES CONDUCTED AT TENTH
STREET.
12. COMMENT: AT WHAT STAGE IS THE APPLICATION FOR THE TAG AND WHEN MIGHT IT BE AWARDED?
EPA RESPONSE: A MAGNAFAX COPY OF THE GRANT APPLICATION IS BEING REVIEWED BY THE EPA REGIONAL
OFFICE IN DALLAS. THE GRANT MAY BE AWARDED IN OCTOBER 1990, PROVIDED THAT AN ORIGINAL, SIGNED
COPY OF THE APPLICATION IS RECEIVED BY THE REGIONAL OFFICE BY SEPTEMBER 30, 1990, AND THE
APPLICATION COMPLIES WITH FEDERAL GRANT REGULATIONS.
13. COMMENT: EPA APPEARS TO BE DELAYING THE AWARD OF A TAG UNTIL THE REMEDIAL ACTION IS
COMPLETED.
EPA RESPONSE: THIS IS NOT TRUE. PREVIOUS DRAFT APPLICATIONS SUBMITTED BY THE LOCAL CITIZEN'S
GROUP SINCE MARCH 1990 HAVE BEEN INCOMPLETE OR INCORRECT. EPA CANNOT, BY GRANT REGULATIONS,
AWARD A TAG UNLESS THE APPLICATION IS COMPLETE AND CORRECT. REPRESENTATIVES FROM EPA HAVE
ASSISTED THE GROUP ON NUMEROUS OCCASIONS IN CORRECTING THE APPLICATION. IN SOME CASES, COMMENTS
ON DRAFT APPLICATIONS WERE NOT ADDRESSED IN SUBSEQUENT SUBMITTAL.
14. COMMENT: WHY WAS ALTERNATIVE 2, CAPPING IN PLACE, NOT CONSIDERED AT TENTH STREET?
EPA RESPONSE: CONSTRUCTION OF A CAP ON THE TENTH STREET SITE WOULD NOT SATISFY THE PREFERENCE
FOR TREATMENT TO REDUCE MOBILITY, TOXICITY, OR VOLUME STATED IN THE SUPERFUND LAW. EPA ALSO
EXPECTS, AS OUTLINED IN THE NATIONAL CONTINGENCY PLAN (NCP), TO TREAT WASTES THAT CONSTITUTE A
PRINCIPAL THREAT AT A SITE. SOILS CONTAMINATED WITH GREATER THAN 300 PPM PCBS ARE CONSIDERED
THE PRINCIPAL THREAT AT TENTH STREET AND BY REGULATION SHOULD BE TREATED. ALSO, CAPPING WAS NOT
CONSIDERED AN APPROPRIATE REMEDY BECAUSE THE SITE IS IN THE 100-YEAR FLOOD PLAIN OF THE NORTH
CANADIAN RIVER AND WOULD REQUIRE PERPETUAL MAINTENANCE TO PREVENT FUTURE EXPOSURE TO
CONTAMINATED SOIL.
15. COMMENT: HOW WAS THE SELECTION OF THE PROPOSED PLAN AMONG ALTERNATIVES 3, 4, AND 5 MADE?
EPA RESPONSE: THESE ALTERNATIVES WERE COMPARED AGAINST NINE CRITERIA OUTLINED IN THE NCP AND THE
STATUTORY PREFERENCES IN THE SUPERFUND LAW. ALTERNATIVE 3, OFFSITE LAND DISPOSAL, DOES NOT MEET
THE STATUTORY PREFERENCE FOR TREATMENT AS A PRINCIPAL ELEMENT OF THE REMEDY. OFFSITE DISPOSAL
WITHOUT TREATMENT IS ALSO THE LEAST PREFERRED ALTERNATIVE FOR SUPERFUND SITES. ALTERNATIVE 5,
ONSITE THERMAL DESTRUCTION, WAS NOT PROPOSED IN FAVOR OF AN INNOVATIVE TECHNOLOGY. THE
SUPERFUND PROGRAM EXPECTS TO SELECT INNOVATIVE TECHNOLOGIES AT SITES WHERE SUCH A TECHNOLOGY IS
PRACTICABLE.
16. COMMENT: WHY IS EPA SELECTING A TECHNOLOGY RATHER THAN WRITING PERFORMANCE SPECIFICATIONS
FOR CLEANING UP THE SITE AND TAKING BIDS ON ACCEPTABLE SOLUTIONS FOR ADDRESSING THE CONTAMINANTS
AT TENTH STREET?
EPA RESPONSE: THE PROCESS BY WHICH EPA SELECTS REMEDIES AT SUPERFUND SITES IS SET FORTH IN THE
NATIONAL CONTINGENCY PLAN (NCP). THE NCP IS THE REGULATION THAT GOVERNS THE SUPERFUND PROGRAM.
THIS PROCESS ALLOWS EPA TO SCREEN OUT THOSE TECHNOLOGIES THAT ARE CLEARLY INAPPROPRIATE FOR THE
TENTH STREET SITE. AS PART OF THE DESIGN PHASE OF THIS PROJECT, PERFORMANCE SPECIFICATIONS WILL
BE WRITTEN. THESE SPECIFICATIONS WILL INCLUDE THE REQUIRED LEVEL OF TREATMENT AND LENGTH OF
TIME REQUIRED TO COMPLETE THE TREATMENT PROCESS.
17. COMMENT: HAS A HEALTH AND SAFETY PLAN FOR THE CONSTRUCTION AT THIS SITE BEEN WRITTEN?
EPA RESPONSE: NO. HOWEVER, A HEALTH AND SAFETY PLAN, OUTLINING COMMUNITY AND WORKER SAFETY
PROCEDURES, MUST BE WRITTEN AND IN PLACE PRIOR TO THE START OF CONSTRUCTION ACTIVITIES AT THE
SITE.
18. COMMENT: WHAT IS THE CURRENT PROJECT SCHEDULE?
EPA RESPONSE: EPA WILL SELECT THE REMEDY FOR TENTH STREET IN SEPTEMBER 1990. THE DESIGN OF THE
SELECTED REMEDY IS SCHEDULED TO BEGIN IN MARCH 1991, AFTER A STATUTORILY REQUIRED MORATORIUM
PERIOD TO ALLOW POTENTIALLY RESPONSIBLE PARTIES, IF ANY, TO TAKE OVER THE PROJECT. THE DESIGN
WILL BE COMPLETED IN MARCH 1992, WITH AN INVITATION FOR BIDS BEING RELEASED BY EPA SHORTLY
THEREAFTER. EPA EXPECTS FIELD WORK TO BE BEGIN IN SUMMER 1992 AND END IN SUMMER 1993.
19. COMMENT: EPA HAD ALREADY SELECTED THE REMEDY AT THE TIME OF THE PUBLIC MEETING.
EPA RESPONSE: THIS IS NOT TRUE. EPA HAD PROPOSED A REMEDIAL TECHNOLOGY FOR THE TENTH STREET
SITE AT THE PUBLIC MEETING. THE PLAN WAS PROPOSED AS THE BEST TECHNICAL SOLUTION FOR THE SITE,
BASED ON THE CRITERIA OUTLINED IN THE NCP. EPA DOES NOT SELECT THE REMEDY FOR A SITE UNTIL ALL
OF THE COMMENTS MADE DURING THE PUBLIC COMMENT PERIOD HAVE BEEN CONSIDERED.
20. COMMENT: WHAT WAS THE PREDOMINANT SPECIES OF PCBS FOUND AT TENTH STREET?
EPA RESPONSE: THE PREDOMINANT SPECIES OF PCBS FOUND AT TENTH STREET WAS AROCLOR 1260.
21. COMMENT: WHAT ARE THE TOXICITY AND PERSISTENCE OF PCBS?
EPA RESPONSE: EPA CURRENTLY CLASSIFIES PCBS AS A CLASS B CARCINOGEN, OR A PROBABLE CARCINOGEN.
THE EPA CANCER ASSESSMENT GROUP HAS ESTIMATED THE CANCER POTENCY FACTOR TO BE 4.0 (MG/KG/DAY)-1
AND HAS USED THIS FACTOR IN HEALTH ADVISORIES ISSUED BY EPA. BASED ON LABORATORY ANIMAL DATA,
THERE IS A POTENTIAL FOR REPRODUCTIVE EFFECTS, DEVELOPMENTAL TOXICITY IN HUMANS EXPOSED TO PCBS.
PCBS ARE ALSO EXTREMELY PERSISTENT IN THE ENVIRONMENT AND CAN BIOACCUMULATE IN THE FATTY TISSUES
OF EXPOSED ORGANISMS (FEDERAL REGISTER, JULY 10, 1986).
22. COMMENT: DOES THE CAP THAT IS CURRENTLY ON THE SITE PROVIDE ADEQUATE PROTECTION OF HUMAN
HEALTH AND THE ENVIRONMENT FORM THE CONTAMINATION AT TENTH STREET?
EPA RESPONSE: NO, IT DOES NOT. THE CAP THAT WAS INSTALLED ON THE SITE IN 1985 BY EPA WAS
INTENDED TO TEMPORARILY PREVENT DIRECT CONTACT AND MIGRATION OF CONTAMINATED SOIL.
STABILIZATION OF THE SITE ALLOWED EPA TO EVALUATE MORE PERMANENT SOLUTIONS TO THE PROBLEMS AT
TENTH STREET. AS SEEN BY THE CURRENT DETERIORATION, THE TEMPORARY CAP DOES NOT PROVIDE ADEQUATE
LONG-TERM PROTECTION. AS STATED PREVIOUSLY, THE DEGREE OF PROTECTION AFFORDED BY ANY CAP IS
QUESTIONABLE BECAUSE THE SITE IS LOCATED IN A 100-YEAR FLOOD PLAIN.
23. COMMENT: TO WHAT EXTENT HAVE PCBS MIGRATED OFFSITE?
EPA RESPONSE: SAMPLES TAKEN DURING THE 1985 REMOVAL ACTION INDICATES THAT THE ONLY OFFSITE PCB
CONTAMINATION EXISTS IN THE RIGHT-OF-WAY BETWEEN THE NORTH SITE BOUNDARY AND TENTH STREET AT A
DEPTH OF 3 TO 4 FEET BELOW THE SURFACE. SURFACE SOILS ARE CLEAN ALONG THE RIGHT-OF-WAY AND DO
NOT POSE A THREAT TO PEDESTRIANS.
24. COMMENT: HOW DEEP WERE SOIL BORINGS DRILLED DURING THE REMEDIAL INVESTIGATION?
EPA RESPONSE: SOIL BORINGS WERE DRILLED TO A DEPTH OF SIX FEET. SOIL SAMPLES TAKEN AT THIS
DEPTH WERE NOT CONTAMINATED ABOVE THE REMEDIAL GOALS, INDICATING THAT DEEPER BORINGS WERE NOT
NECESSARY.
25. COMMENT: CAN EPA PROMOTE THE USE OF LOCAL FIRMS FOR THE REMEDIAL WORK AT TENTH STREET?
EPA RESPONSE: EPA CANNOT GIVE PREFERENCE TO LOCAL CONTRACTORS BECAUSE OF THEIR LOCATION.
HOWEVER, LOCAL COMPANIES CAN HAVE A COMPETITIVE ADVANTAGE DUE TO LOWER TRANSPORTATION COSTS. BY
THE FEDERAL ACQUISITION REGULATIONS, THE SELECTION OF A CONTRACTOR TO IMPLEMENT THE SELECTED
REMEDY MUST BE DONE THROUGH AN OPEN AND COMPETITIVE BIDDING PROCESS. EPA'S PRIME CONTRACTOR MUST
ALSO SELECT SUBCONTRACTORS IN THIS MANNER.
26. COMMENT: WHAT WILL THE CONSULTANT HIRED TO DESIGN THE REMEDY ACTUALLY DO?
EPA RESPONSE: THE REMEDIAL DESIGN CONSULTANT WILL DEVELOP THE CONTRACTS AND BID DOCUMENTS
NECESSARY TO PROCURE A CONTRACTOR TO IMPLEMENT THE REMEDY SELECTED IN THE RECORD OF DECISION.
THE CONSULTANT WILL NOT BE DIRECTED TO SELECT A REMEDY FOR TENTH STREET. THE CONSULTANT WILL
ALSO DEVELOP THE SPECIFICATIONS AND BLUEPRINTS FOR THE REMEDY AND METHODS OF VERIFYING THE
PERFORMANCE OF THE CONTRACTOR.
27. COMMENT: SHOULDN'T A CONSULTANT BE HIRED TO RECOMMEND A REMEDY FOR TENTH STREET?
EPA RESPONSE: CONSULTANTS MAY BE HIRED TO DEVELOP AND EVALUATE POTENTIAL REMEDIAL ALTERNATIVES
FOR CONSIDERATION BY EPA. THE RESPONSIBILITY TO RECOMMEND AND SELECT REMEDIES AT SUPERFUND
SITES IS SOLELY EPA'S BY LAW.
28. COMMENT: IS THE EQUIPMENT NECESSARY FOR CHEMICAL DECHLORINATION COMMERCIALLY AVAILABLE?
EPA RESPONSE: YES, ONE MANUFACTURER, GALSON INC., OF SYRACUSE, NEW YORK, HAS BUILT A FULL-SCALE
UNIT FOR USE WITH CONTAMINATED SOILS. OTHER FULL-SCALE UNITS HAVE BEEN USED AT THE SITES
DISCUSSED IN THE RESPONSE TO COMMENT 6.
29. COMMENT: HOW MUCH TIME WILL BE REQUIRED TO TREAT EACH BATCH OF CONTAMINATED SOIL IN THE
CHEMICAL DECHLORINATION UNIT?
EPA RESPONSE: EXPERIENCES AT OTHER SITES AND THE TREATABILITY STUDY CONDUCTED ON THE TENTH
STREET SOIL INDICATE THAT EACH BATCH OF SOIL CAN BE TREATED TO LESS THAN 2.0 PPM PCBS IN
APPROXIMATELY 4 HOURS. AT THIS RATE, THE 7,500 CUBIC YARDS OF SOIL AT TENTH STREET CAN BE
TREATED IN APPROXIMATELY 9 MONTHS.
30. COMMENT: WHAT VOLUMES OF SOIL AND REAGENT ARE MIXED TOGETHER IN THE CHEMICAL DECHLORINATION
PROCESS?
EPA RESPONSE: APPROXIMATELY 2 TONS OF SOIL ARE TREATED BY 1 TON OF REAGENT (POTASSIUM OR SODIUM
HYDROXIDE, POLYETHYLENE GLYCOLATE 400, AND DIMETHYL SULFOXIDE) IN EACH BATCH TREATMENT PROCESS.
THE REAGENTS ARE RECOVERED FOR REUSE IN SUBSEQUENT BATCHES.
31. COMMENT: HOW LARGE WILL THE EXCAVATION AREA ONSITE BE DURING IMPLEMENTATION OF THE REMEDY?
EPA RESPONSE: THE EXCAVATED AREA WILL BE APPROXIMATELY EQUAL TO THE RATE OF TREATMENT. FOR
EXAMPLE, EPA ASSUMED IN THE FEASIBILITY STUDY THAT 30 CUBIC YARDS OF SOIL WOULD BE TREATED PER
DAY. EXCAVATION WOULD BE DONE AT THE SAME RATE WITH SOME MATERIAL BEING STOCKPILED PRIOR TO
TREATMENT.
32. COMMENT: DID THE REMEDIAL INVESTIGATION INDICATE THE EXTENT OF THE ORIGINAL LANDFILL AT THE
SITE?
EPA RESPONSE: NO, IT DID NOT. EPA WAS PRIMARILY INTERESTED IN PCB CONTAMINATION AT THE SITE.
HOWEVER, SAMPLES TAKEN FROM BORINGS AND MONITORING WELLS INDICATED THAT NO REMNANTS FROM THE
ORIGINAL LANDFILL EXIST AT THE SITE.
33. COMMENT: WILL THE MATERIAL UNDER THE PCB-CONTAMINATED SOIL SUPPORT HEAVY EQUIPMENT THAT MAY
BE NEEDED TO IMPLEMENT THE SELECTED REMEDY?
EPA RESPONSE: YES. SOIL LOGS TAKEN FROM BORINGS DURING THE REMEDIAL INVESTIGATION INDICATE THAT
THE DEEPER SOIL IS SOLID AND WILL SUPPORT HEAVY EQUIPMENT.
34. COMMENT: WILL THE SELECTED REMEDY BE SUFFICIENT TO ADDRESS ANY ADDITIONAL CONTAMINATION THAT
MAY BE FOUND AFTER EXCAVATION BEGINS?
EPA RESPONSE: YES, IT WILL BE ABLE TO HANDLE ANY ADDITIONAL SOIL FOUND AT THE SITE. HOWEVER,
THE LENGTH OF TIME REQUIRED TO COMPLETE THE REMEDIAL ACTION WILL INCREASE.
35. COMMENT: WILL THERE BE ANY REASON TO CLOSE OFF PARTS OF TENTH STREET TO TRAFFIC DURING
REMEDIATION?
EPA RESPONSE: NO, THERE WON'T BE ANY REASON TO CLOSE OF THE STREET TO TRAFFIC. WINDBLOWN DUST
WILL BE CONTROLLED BY SPRAYS AND KEEPING THE AREA OF EXCAVATION TO A MINIMUM. CHEMICAL
DECHLORINATION WILL BE DONE IN A COMPLETELY ENCLOSED UNIT, INCLUDING REAGENT MIXING, ELIMINATING
AIR EMISSIONS FROM THE PROCESS. SHOULD WEATHER CONDITIONS INHIBIT EXCAVATION, OPERATIONS WOULD
BE POSTPONED AS A PRECAUTION.
36. COMMENT: WHY WAS TENTH STREET SELECTED FOR CLEANUP AS OPPOSED TO OTHER SITES IN THE AREA?
EPA RESPONSE: LEAKING DRUMS DISCOVERED ON THE SITE IN 1985 WERE REMOVED BY EPA TO PREVENT ANY
EXPOSURE TO LOCAL POPULATIONS OR THE ENVIRONMENT. BECAUSE OF THE PRESENCE OF PCBS IN THE SOIL
AND THE POTENTIAL FOR FUTURE EXPOSURE, THE SITE WAS PLACED ON THE NATIONAL PRIORITIES LIST,
BECOMING ELIGIBLE FOR FUNDING FOR INVESTIGATIONS AND PERMANENT REMEDIAL ACTION.
37. COMMENT: DOES THE TENTH STREET SITE HAVE THE HIGHEST HAZARD RANKING SYSTEM SCORE OF ANY NPL
SITE IN THE OKLAHOMA CITY AREA?
EPA RESPONSE: NO. TWO OTHER NPL SITES, TINKER AIR FORCE BASE AND THE MOSLEY ROAD LANDFILL HAVE
HIGHER SCORES. IT SHOULD BE NOTED THAT RELATIVE SCORES ARE NOT USED TO SET REMEDIAL PRIORITIES
AMONG SUPERFUND SITES AND REPRESENTS ONLY A CONSERVATIVE RATING OF POTENTIAL THREATS BEFORE ANY
INTENSIVE STUDIES ARE CONDUCTED.
38. COMMENT: WILL FURTHER TREATMENT OF RESIDUALS BE REQUIRED AFTER CHEMICAL DECHLORINATION IS
COMPLETED?
EPA RESPONSE: YES. APPROXIMATELY 10 TONS OF SOLID RESIDUE FROM THE TREATMENT PROCESS WILL
REQUIRE OFFSITE DISPOSAL AS A PCB WASTE. REAGENTS ARE RECOVERED AND THE TREATED SOIL WILL BE
USED AS BACKFILL ONSITE.
39. COMMENT: IS THE CHEMICAL DECHLORINATION PROCESS A PATENTED PROCESS?
EPA RESPONSE: THE GENERAL PROCESS IS NOT PATENTED. HOWEVER, THE USE OF PROPRIETARY CHEMICALS OR
SPECIALIZED EQUIPMENT HAS LED TO PATENTS ON THOSE VARIATIONS BY VENDORS. CONTRACTORS WOULD HAVE
TO NEGOTIATE FOR PATENT RIGHTS OR LEASES WITH VENDORS TO USE SPECIFIC EQUIPMENT.
40. COMMENT: PCBS AT TENTH STREET DO NOT CURRENTLY POSE A THREAT TO THE SURROUNDING COMMUNITY;
SUCH A THREAT MAY POTENTIALLY RESULT ONLY IF THE SITE WAS DISTURBED.
EPA RESPONSE: EPA NEVER INDICATED THAT THE SITE POSED A CURRENT THREAT TO THE COMMUNITY. THE
NEED TO TAKE REMEDIAL ACTION IS BASED ON THE REASONABLE MAXIMUM EXPOSURE EXPECTED UNDER FUTURE
COMMERCIAL LAND USE. THE CONSIDERATION OF FUTURE LAND USE IN SETTING REMEDIAL ACTION GOALS IS
CONSISTENT WITH THE NATIONAL CONTINGENCY PLAN AND THE RISK ASSESSMENT GUIDANCE FOR SUPERFUND,
VOLUME 1, DECEMBER 1989. EPA CONSIDERS FUTURE LAND USE TO BE REASONABLE AT TENTH STREET BASED
ON THE CURRENT SURROUNDING LAND USE (COMMERCIAL) AND INQUIRIES THAT HAVE BEEN MADE TO EPA BY
PARTIES INTERESTED IN COMMERCIAL DEVELOPMENT OF THE PROPERTY.
41. COMMENT: REMEDIAL ACTION AT TENTH STREET IS CONTRARY TO NATIONAL POLICY BECAUSE THE
BASELINE (CURRENT) RISK AT THE SITE IS ALREADY WITHIN THE REMEDIAL TARGET RANGE SET BY EPA.
EPA RESPONSE: THE NATIONAL CONTINGENCY PLAN (NCP) AND NATIONAL POLICY DICTATE THAT REMEDIAL
ACTION BE TAKEN AT THE SITE. THE NCP 10-6 (I.E., 1 IN 1,000,000) RISK LEVEL AS THE "POINT OF
DEPARTURE" FOR DETERMINING REMEDIAL ACTION GOALS WHEN OTHER STANDARDS ARE NOT AVAILABLE. EPA
EXPECTS TO ACHIEVE THIS LEVEL OF PROTECTION WHEN PRACTICABLE.
THE NCP ALSO DICTATES THAT REMEDIAL ACTIONS COMPLY WITH APPLICABLE AND RELEVANT AND APPROPRIATE
REGULATIONS AND OTHER POLICIES AND GUIDELINES. THESE ARE LISTED IN THE PREAMBLE TO THE NCP AND
INCLUDE THE TOXIC SUBSTANCES CONTROL ACT PCB SPILL CLEANUP POLICY (FEDERAL REGISTER, APRIL 2,
1987). AS A MATTER OF POLICY, EPA COMPLIES WITH THE CLEANUP LEVELS SET IN THE SPILL CLEANUP
POLICY. FOR COMMERCIAL AREAS, THIS LEVEL IS SET AT 25 PPM PCBS IN SOIL. OF THE 32 RECORDS OF
DECISION SIGNED SINCE THE PASSAGE OF SARA, FOR SITES WHERE PCBS ARE THE CONTAMINANT OF CONCERN,
5 HAVE SELECTED CLEANUP LEVELS OF 25 PPM PCBS. MORE STRINGENT CLEANUP LEVELS (10 PPM OR LESS)
HAVE BEEN SET AT SITES WHERE RESIDENTIAL EXPOSURES WERE CONSIDERED.
42. COMMENT: PHYSICAL AND LEGAL RESTRICTIONS COULD PROVIDE A LEVEL OF PROTECTION COMPARABLE TO
ANY REMEDIAL ACTION TAKEN AT THE SITE.
EPA RESPONSE: SECTION 300.430 (A)(III) OF THE NCP STATES THAT INSTITUTIONAL CONTROLS SHALL NOT
SUBSTITUTE FOR ACTIVE RESPONSE ACTIONS AS THE SOLE REMEDY UNLESS SUCH ACTIVE MEASURES ARE
IMPRACTICABLE. AS THIS IS NOT THE CASE AT TENTH STREET. SARA EXPECTS TO USE TREATMENT, NOT
PHYSICAL RESTRICTIONS, AS THE PRINCIPAL ELEMENT OF REMEDIAL ACTIONS AT SUPERFUND SITES.
43. COMMENT: THE RISK ASSOCIATED WITH THE OPERATION OF THE CHEMICAL DECHLORINATION PROCESS
SHOULD BE COMPARED TO THE LONG-TERM RISKS POSED BY THE EXISTING SITE.
EPA RESPONSE: EPA DOES NOT MEASURE SHORT-TERM RISKS IN THE SAME MANNER THAT LONG-TERM RISKS ARE
MEASURED. HOWEVER, THE TOXICITIES OF THE REAGENTS AND BYPRODUCTS OF THE PROCESS CAN BE COMPARED
TO THE TOXICITY OF PCBS AS A MEASURE OF THE RELATIVE RISKS. A COMPARISON OF THE REAGENTS, THE
BYPRODUCTS, PCBS, AND OTHER REFERENCE MATERIALS IS PRESENTED BELOW:
MATERIAL LD50, ORAL-RATS
POLYETHYLENE GLYCOL-400 27,500 MG/KG
DIMETHYL SULFOXIDE 17,500 MG/KG
PCBS 1,010 MG/KG
THIS DATA INDICATES THAT PCBS, THE CONTAMINANTS OF CONCERN AT TENTH STREET, ARE 27 TIMES MORE
TOXIC THAN POLYETHYLENE GLYCOLATE AND 17 TIMES MORE TOXIC THAN DIMETHYL SULFOXIDE, THE REAGENTS
IN THE CHEMICAL DECHLORINATION PROCESS. ETHYLENE GLYCOL-400 IS ALSO APPROVED BY THE FOOD AND
DRUG ADMINISTRATION FOR USE IN FOOD AND COSMETICS. THE LD50 IS THE DOSE THAT CAUSES MORTALITY
IN 50 PERCENT OF THE TEST ORGANISMS. THESE TESTS WERE CONDUCTED ON LABORATORY RATS, CONSIDERING
ORAL INGESTION. EPA RESEARCH ALSO INDICATES THAT DECHLORINATED MIXTURES OF 2,3,7,8-TETRADIOXIN
ARE 350 TIMES LESS TOXIC THAN 2,3,7,8-TETRADIOXIN ITSELF. THE TREATMENT BY PRODUCTS DO NOT
DEMONSTRATE ANY CARCINOGENIC POTENTIAL BASED ON THE RESULTS OF AMES TESTS CONDUCTED BY EPA.
MATERIALS HANDLING WILL NOT POSE ANY SHORT TERM RISK DURING IMPLEMENTATION OF THE REMEDY.
EXISTING CHEMICAL DECHLORINATION EQUIPMENT IS COMPLETELY AUTOMATED. REAGENTS, BYPRODUCTS, AND
SOILS ARE HANDLED IN COMPLETELY ENCLOSED SYSTEMS USING PUMPS AND CONVEYOR BELTS FOR MATERIALS
HANDLING. THE SYSTEM ALSO ADDRESSES AIR EMISSIONS THROUGH CONDENSORS FOR WATER VAPOR AND CARBON
FILTERS FOR VOLATILE ORGANICS. NO CONTAMINANTS ARE RELEASED TO THE ATMOSPHERE DURING THE
TREATMENT PROCESS.