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Record of Decision System (RODS)
COMMENCEMENT BAY, NEAR SHORE/TIDE FLATS
Abstract
| Site Name: | COMMENCEMENT BAY, NEAR SHORE/TIDE FLATS |
| Address: | ADJ TO RUSTON WAY & TIDEFLATS IND. AREA |
| City & State: | PIERCE COUNTY WA 98421 |
| County: | PIERCE |
| EPA ID: | WAD980726368 |
| EPA Region: | 10 |
| NPL Status: | Currently on the Final NPL |
| ROD Type: | Record of Decision |
| ROD ID: | EPA/ROD/R10-88/011 |
| ROD Date: | 12/30/1987 |
| Operable Unit(s): | 23 |
| Media: | SOIL SURFACE WATER |
| Contaminant: | METALS (LEAD), PAHS, VOCS (BENZENE, PCBS) |
| Abstract: |
THE TACOMA TAR PITS SITE COVERS APPROXIMATELY 30 ACRES WITHIN THE COMMENCEMENT BAY - NEARSHORE/TIDEFLATS SITE IN TACOMA, PIERCE COUNTY, WASHINGTON. THE TAR PITS LIE BETWEEN THE PUYALLUP RIVER, THE CITY, AND WHEELER - OSGOOD WATERWAYS. THESE BODIES OF WATER ARE NOT USED AS A WATER SUPPLY, BUT SUPPORT EXTENSIVE FISH AND SHELLFISH POPULATIONS. CURRENTLY THERE IS CONCERN FOR THE SITE'S IMPACT ON SURFACE WATER QUALITY AND MANY LOCAL INDUSTRIES THAT USE GROUND WATER FROM ONSITE WELLS. IN 1924, A COAL GASIFICATION PLANT BEGAN OPERATIONS, AND CONTINUED UNTIL 1956, AT WHICH TIME THEY WERE TERMINATED DUE TO THE AVAILABILITY OF NATURAL GAS. DURING THESE YEARS, WASTE MATERIALS FROM THE COAL GASIFICATION PROCESS WERE DISPOSED OF ONSITE. CONTAINED IN THE WASTE MATERIALS, WERE A WIDE VARIETY OF ORGANIC COMPOUNDS AND HEAVY METALS. FROM 1965 TO 1966, THE PLANT WAS DISMANTLED AND DEMOLISHED. MOST OF THE METAL STRUCTURES WERE REMOVED FROM THE SITE; HOWEVER, ALL DEMOLITION DEBRIS AND BELOW GRADE STRUCTURES WERE LEFT IN PLACE, INCLUDING TANKS AND PIPELINES CONTAINING TARS. IN 1967, A METAL RECYCLING COMPANY BEGAN OPERATING AT THE SITE. RECYCLING OF AUTOMOBILE BATTERIES INTRODUCED ACID, HEAVY METALS, LEAD, AND PCBS TO THE SOIL. SEVERAL STUDIES CONDUCTED BY EPA AND THE WASHINGTON STATE DEPARTMENT OF ECOLOGY BETWEEN 1981 AND 1983 FOUND CONTAMINANTS DERIVED FROM THE COAL GASIFICATION PROCESS. THE PRIMARY CONTAMINANTS OF CONCERN AFFECTING SURFACE WATER AND SOIL INCLUDE; BENZENE, PAHS, PCBS, AND LEAD. THE SELECTED REMEDIAL ACTION FOR THIS SITE INCLUDES; EXCAVATION OF ALL CONTAMINATED SOILS EXCEEDING 1 PERCENT TOTAL PAHS AND ALL SURFACE SOILS EXCEEDING A 10-6 LIFETIME CANCER RISK LEVEL WITH STABILIZATION OF ALL EXCAVATED SOILS IN A POLYMER/CEMENT MIXTURE; CAPPING OF THE STABILIZED MATRIX WITH ASPHALT; CHANNELING AND MANAGING OF SURFACE WATERS; GROUND WATER MONITORING; AND REMOVAL AND TREATMENT OF PONDED WATER. THE ESTIMATED PRESENT WORTH COST FOR THIS REMEDIAL ACTION IS $3,400,000. |
| Remedy: |
THIS RECORD OF DECISION ADDRESSES SOURCE CONTROL OF ON-SITE CONTAMINATION THROUGH EXCAVATION OF CONTAMINATED SOILS AND STABILIZATION OF THESE CONTAMINATED SOILS IN A POLYMER/CEMENT MATRIX. THE STABILIZED MATRIX WILL BE CAPPED TO REDUCE SURFACE-WATER INFILTRATION. MANAGEMENT OF MIGRATION IS ADDRESSED BY DIVERSION OF SURFACE-WATER RUNOFF. ON-SITE SHALLOW GROUNDWATER CONTAINS DETECTABLE CONCENTRATIONS OF CONTAMINANTS. HOWEVER, BECAUSE CONTAMINATION HAS NOT BEEN DETECTED OFF-SITE AND AS THE REMEDIAL ACTION IS EXPECTED TO PREVENT FURTHER CONTAMINATION, GROUNDWATER EXTRACTION AND TREATMENT IS NOT CONSIDERED AS APPROPRIATE AT THIS TIME. SHOULD MONITORING INDICATE CONTAMINATION MIGRATION, FURTHER TREATMENT MAY BE NECESSARY, TO ADDRESS THE SHALLOW GROUNDWATER. THE REMEDIAL ACTION IS DESIGNED TO; - EXCAVATE AND TREAT ALL CONTAMINATED SOILS CONSIDERED TO BE EXTREMELY HAZARDOUS WASTES (EHW) DEFINED FOR THIS SITE AS EXCEEDING 1 PERCENT TOTAL POLYNUCLEAR AROMATIC HYDROCARBON; - EXCAVATE AND TREAT (STABILIZE) ALL SURFACE SOILS (LT 3 FEET) CONTAINING CONTAMINANTS THAT EXCEED A 10-6 LIFETIME CANCER RISK LEVEL; - REDUCE SURFACE WATER INFILTRATION AND POTENTIAL HUMAN EXPOSURE TO STABILIZED SOILS BY CAPPING THE STABILIZED MATRIX WITH ASPHALT; - REDUCE SURFACE WATER TRANSPORT OF CONTAMINANTS BY CHANNELING AND MANAGING SURFACE WATERS; AND - PROVIDE FOR CONTINUED GROUNDWATER MONITORING TO EVALUATE THE EFFECTIVENESS OF THE REMEDIAL ACTION AND THE NEED FOR GROUNDWATER EXTRACTION AND TREATMENT; - REMOVE AND TREAT PONDED WATER TO ACHIEVE CLEANUP GOALS. TREATMENT WILL BE SUFFICIENT TO REDUCE CONTAMINANT LEVELS IN THE SOILS, AND SURFACE WATERS TO OR BELOW CLEANUP STANDARDS. NUMERIC VALUES FOR THESE CLEANUP STANDARDS AND THE CRITERIA USED IN PERFORMANCE STANDARD DEVELOPMENT ARE PRESENTED IN TABLE 1. TREATMENT SHOULD BE PERMANENT, AND SHOULD EFFECTIVELY REDUCE THE TOXICITY AND MOBILITY OF THE CONTAMINANTS. PERFORMANCE LEVELS ARE NOT TO BE EXCEEDED DURING THE OPERATIONAL LIFE OF THE REMEDIAL ACTION. ALTHOUGH TABLE 1 CONTAINS CLEANUP STANDARDS FOR GROUNDWATER THE REMEDIAL ACTION DOES NOT CURRENTLY PROVIDE FOR GROUNDWATER EXTRACTION AND TREATMENT. SOURCE CONTROL MEASURES ARE EXPECTED TO REDUCE CONTAMINANT CONCENTRATIONS IN THE LOCAL GROUNDWATER SYSTEM. GROUND WATER MONITORING PERFORMED DURING IMPLEMENTATION AND FOLLOWING THE REMEDIAL ACTION WILL AID IN DETERMINING THE EFFECTIVENESS OF THE REMEDIAL ACTION. IF CLEANUP LEVELS ARE NOT ACHIEVED AT THE SITE BOUNDARY IN THE AQUIFERS WITHIN A REASONABLE PERIOD OF TIME FOLLOWING COMPLETION OF THE REMEDIAL ACTION, AN ALTERNATIVE REMEDIAL ACTION WILL BE EVALUATED AND IMPLEMENTED WHICH MAY INCLUDE GROUNDWATER EXTRACTION. CONTINUED MONITORING OF SURFACE WATERS WILL ALSO BE PERFORMED TO ENSURE CLEANUP LEVELS ARE MET DURING AND FOLLOWING IMPLEMENTATION OF THE REMEDIAL ACTION. TREATED WATER DISCHARGE SHALL AT ALL TIMES BE OF QUALITY CONSISTENT WITH U.S. AND WASHINGTON STATE LAWS. INSTITUTIONAL CONTROLS SUCH AS DEED RESTRICTIONS TO PROHIBIT EXCAVATION OR DRILLING WILL BE DEVELOPED, CONSISTENT WITH THE FINAL DESIGN, TO ENSURE THAT THE REMEDIAL ACTION WILL CONTINUE TO PROTECT HUMAN HEALTH AND THE ENVIRONMENT. IN COMPLIANCE WITH SARA THE EFFECTIVENESS AND PERFORMANCE OF THIS FINAL REMEDIAL ACTION WILL BE REASSESSED AT REGULAR INTERVALS, NOT TO EXCEED 5 YEARS. |
| Text: |
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