UNDERGROUND STORAGE TANK CLOSURE REPORT FOR 550-GALLON DIESEL FUEL TANK (GWA ALUPANG) AT GUAM WATERWORKS AUTHORITY ALUPANG SEWAGE PUMPING STATION TAMUNING, GUAM
March 2011
Prepared for:
Guam Environmental Protection Agency
17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
Prepared by:
apec allied pacific environmental consulting P.O. BOX 5091 AGANA, GUAM 96932 T 671.477.7310/12 | F 671.477.7311 | apecguam@guam.net
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Guam EPA, UST Closure Report GWA Tamuning, Sewer Pumping Station (Alupang), 550 Gal March 2011
1.0 EXECUTIVE SUMMARY 1.1 Introduction A 550-gallon fiberglass reinforced plastic (FRP) underground storage tank (UST) was removed from the Guam Waterworks Authority (GWA), Alupang Sewage Pumping Station (ASPS) Tamuning, Guam in Jul y 2010. Confi rmation soil sampli ng wa s conducted on 13 July 2010. Olfa ctory, PID scre ening an d confirmation soil sample analytical results indicate minor petroleum impacts to the soil below the piping of the UST. 1.2 Sequence of UST Closure Activities Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an e nclosure to this report. Th e concrete-slab demolition was conducted on. 13, July 2010. Liquid tank content s were rem oved and disposed of o n 13 , Ju ly 2010. A Certified Indu strial Hyg ienist (CIH) provided Ga s-Free Certification on 13, July 201 0. UST si dewall soil excavation wa s conducted o n 13 July, 2010. The UST and associated piping was removed from the site and properly disposed or recycled on. Soil sam ples were collected for confirmation analysis on 13 July, 2010. Followin g the direction a nd under the supervision of Guam EPA APEC personnel backfilled the excavation area on 14-16 July 2010. 1.3 Site Investigation Activities Site investigation activities consisted of visual, olfactory and PID fi eld screening and laboratory analytical soil testing for the following analyt es: 1) Extractable Petroleum Hydrocarbons by EPA Method 8015M, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270SIM and 3) Benzene, Toluene, Ethylbenzene, Xylene by EPA Method 8260. 1.4 Field Screening and Soil Sample Analytical Results Based o n visual, olfa ctory, PID scree ning an d co nfirmation soil analytical result s indi cate either not detected belo w the repo rting limit or n ot detected below the Regional Scree ning Level s e stablished fo r the project. 1.5 Site Conceptual Model The site conceptual model is ba sed upon field ob servations and laboratory analytical testing performed on environmental media collected at the site and the geological and hydrological conditions at the site. Elevations within the pe rimeter fence of the site range from approximately 19ft – 20ft above MSL. The slope within the perimeter fence of the site is 0.03ft per foot (3% slope) and is visibly flat. The elevation at the site of th e UST excavation pit is app roximately 20ft above MSL. Approximately one-hundred-percent (100%) of the site is covered by impervious surfaces including buildings, concrete footings, and pavement The a reas to the south a nd e ast of th e site are u ndeveloped a nd veg etated with grass and T angentangen (Leucaena leucocephala). To th e north of the site is a paved road (Alupang St.). To the we st of the site is a parking lot. Storm water from the nearby rooftop of the generator building associated with the subject UST, drains directly onto the p aved ground surface and flows ho rizontally across the pavement and infiltrates into veg etated buffers surrounding the pavement. The fuel lines of the UST were located approximately 24 in ches bgs an d a ppeared to be undamaged. Site tech nicians ob served no re sidual amounts of fuel contained in the separated fuel line. 1.6 Verification of Site Conceptual Model The two fuel lines leading between the UST and the associated diesel-electric generator were structurally intact and had minimal corrosion. The fuel lines contained no observed residual amounts of fuel. The soil in the area of the separated fuel line was n ot n oted to exhibit olfactory or PID test evid ence of TPH contamination. All analytes tested in soils obtained at the site were found to be below regulatory limits, see Section 4.4, Table 3, for applicable U.S. EPA Region IX, Regional Screening Levels, May 2010.
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Guam EPA, UST Closure Report GWA Tamuning, Sewer Pumping Station (Alupang), 550 Gal March 2011
1.7 Conclusions and Recommendations Based u pon these findin gs it is evi dent that there are no si gnificant im pacts to soils at the site. No corrective actions are recommended at this time.
2
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P.O. BOX 5091, HAGATNA, GUAM 96932 | TEL. 671.477.7310/12/14 | FAX 671.477.7311 | apecguam@ guam.net
ALUPANG UST SITE LOCATION
apec allied pacific environmental consulting
TITLE: MAP OF GUAM, INDICATING SITE LOCATION PROJECT: UST CLOSURE REPORT FOR 550-GALLON DIESEL FUEL TANK (GWA ALUPANG)
FIGURE: 1
ALUPANG UST SITE LOCATION
APPROXIMATE SCALE
0
apec allied pacific environmental consulting
0.5
1
MILES
TITLE: PROJECT SITE VICINITY MAP. PROJECT: UST CLOSURE REPORT FOR 550-GALLON DIESEL FUEL TANK (GWA ALUPANG) 1999 USGS
Figure: 2
ALUPANG STREET
ANALYTICAL RESULTS SAMPLE ALU071310001 ALL ANALYTICALS, ND
NORTH
UNPAVED GROUND
SAMPLE ALU071310002 TOTAL EFH-10.7 mg/kg
FENCELINE (PART OF FENCE REMOVED DURING REMOVAL OF UST)
ALL OTHER ANALYTICALS, ND SAMPLE ALU071310003
SAMPLE ALU071310001 DISCRETE, DEPTH, 8’ bgs
TOTAL EFH-22.6 mg/kg ALL OTHER ANALYTICALS, ND
CRANE
SAMPLE ALU071310002 DISCRETE, DEPTH 8.5’ bgs
EXCAVATED AREA
SAMPLE ALU071310003 COMPOSITE DEPTH, 26” bgs
allied pacific environmental consulting
VEGETATION
BUILDING
GRAB SAMPLE COMPOSITE SAMPLE
apec
CONCRETE SLAB
SOIL STOCKPILE APPROXIMATE SCALE
0
12.5
25
TITLE: SITE PLAN INDICATING SAMPLE LOCATIONS AND ANALYTICAL RESULTS PROJECT: UST CLOSURE REPORT FOR 550-GALLON DIESEL FUEL TANK (GWA ALUPANG)
Figure: 3
FEET
UNDERGROUND STORAGE TANK CLOSURE REPORT FOR 600-GALLON DIESEL FUEL TANK (ASNAMO) AT GUAM WATERWORKS AUTHORITY AS NAMO SEWAGE TRANSFER STATION YONA, GUAM
June 2011
Prepared for: Guam Environmental Protection Agency 17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
Prepared by:
apec allied pacific environmental consulting P.O. BOX 5091 AGANA, GUAM 96932 T 671.477.7310/12 | F 671.477.7311 | apecguam@guam.net
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Guam EPA, UST Closure Report GWA As Namo Sewage Transfer Station, 600G, Yona, Guam June 2011
1.0 EXECUTIVE SUMMARY Introduction A 600-gallon double walled fiberglass underground storage tank (UST) was removed from the Guam Waterworks Authority (GWA), As Namo Sewage Transfer Station (ANSPS), Yona, Guam in August 2010. Confirmation soil sampling was conducted on 11 August 2010. Olfactory, PID screening and confirmation soil sample analytical results do not indicate petroleum impacts to the soil below the UST cavity or associated piping. No significant impacts to groundwater were revealed as a result of field investigation. Sequence of UST Closure Activities Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an enclosure to this report. The concrete-slab demolition was conducted on 11 August 2010. Liquid tank contents were removed and disposed of on 12 August 2010. A Certified Industrial Hygienist (CIH) provided Gas-Free Certification on 12 August 2010. UST sidewall soil excavation was conducted on 11 August 2010. The UST and associated piping was removed from the site and properly disposed of on 18 August 2010. Soil samples were collected for confirmation analysis on 11 August 2010. Following the direction and under the supervision of Guam EPA, APEC personnel backfilled the excavation area on 18 August 2010. Site Investigation Activities Site investigation activities consisted of visual, olfactory and PID field screening and laboratory analytical soil testing for the following analytes: 1) Total Extractable Fuel Hydrocarbons (EFH) by EPA Method 8015B, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270C and 3) Benzene, Toluene, Ethylbenzene, Total Xylenes by EPA Method 8260B. Field Screening and Soil Sample Analytical Results Visual, olfactory, PID screening and confirmation soil analytical results do not indicate concentrations of petroleum hydrocarbons beneath the UST cavity or associated piping. A detectable concentration of diesel range organics (DRO) was detected in the composite sample taken from the soil stockpile. Site Conceptual Model The site conceptual model is based on field observations and laboratory analytical testing performed on environmental media collected at the site and the geological and hydrological conditions at the site. Elevations within the perimeter fence of the site range from approximately 251ft – 257ft above MSL. The slope within the perimeter fence of the site is visibly flat. However, the site was built flat and the ground surface at the site was reinforced using a retaining wall. The original slope of the hillside situated below the site is approximately 0.17ft per foot (17% slope). The elevation at the site of the UST excavation pit is approximately 254ft above MSL. Approximately fifty-percent (50%) of the site is covered by impervious surfaces including buildings, concrete footings, and pavement. The remaining undeveloped areas of the site are vegetated with grass. The undeveloped portions of the property absorb a portion of the stormwater run-off from the site. Storm water drains from the nearby rooftop of the generator building associated with the subject UST through a vertical conduit onto the ground surface near the location of the UST. The two fuel lines leading between the UST and the associated diesel-electric generator were observed to be completely corroded through to the point of disconnection near the openings of entry into the building. The corroded fuel line was located directly below an area where vertical stormwater drainage flowed through a hole in the roof at the location where the UST vent pipe was previously installed. It is likely this corrosion occurred after the tank was no longer being used to store fuel. Site observation PID field testing and soil testing results revealed no significant fuel impacts to the subsurface. Depth to groundwater at the location of the UST excavation is approximately 251 ft below ground surface. No significant drinking water sources exist within 1000 feet of the facility. The prevailing groundwater flow is generally to the northeast towards the Pago River and the Pago Bay. Subsurface porosities in the vicinity of the site are mixed due to the heterogeneous nature of the artificial fill that has been deposited in 1 of 11
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Guam EPA, UST Closure Report GWA As Namo Sewage Transfer Station, 600G, Yona, Guam June 2011
the area. Hydraulic conductivities in the artificial fill materials are estimated to be low to moderate within the vicinity of the site. Verification of Site Conceptual Model The double-walled fiberglass UST was observed to be intact. The UST and piping showed no indication of former leakage. PID field tests and visual and olfactory examination of the soil below the UST and fuel piping revealed no indication of leakage. Laboratory analytical results from the soil sample collected beneath the tank cavity did not indicate the presence of petroleum hydrocarbons above the laboratory’s detection limits. The composite soil stockpile sample contained concentrations of DRO (7.17 mg/kg) and fluorene (0.00727 mg/kg). All other constituents of concern were not detected above laboratory detection limits. Conclusions and Recommendations Non-actionable impacts of fuel related contaminants were evident in the overburden soil removed and sockpiled during UST closure proceedings. No impacts to soil below the UST were discovered. Future release of fuel from this location has been prevented by the removal of the UST and associated piping. Based on a review of the evidence presented within this UST closure report it is recommended that no further action be considered at the site.
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ASNAMO UST SITE LOCATION
N
TITLE: MAP OF GUAM, INDICATING SITE LOCATION
apec allied pacific environmental consulting
PROJECT: GUAM EPA, ASNAMO UST CLOSURE REPORT
FIGURE: 1
SUBJECT SITE
N SCALE: KILOMETERS 0
apec
SHEET TITLE: TOPOGRAPHIC MAP OF SUBJECT SITE VACINITY
allied pacific environmental consulting
PROJECT: GUAM EPA, ASNAMO, UST CLOSURE REPORT MAP PROVIDED COURTESY OF UNITED STATES GEOLOGICAL SERVICE 2000
0.5
1.0
FIGURE: 2
ANALYTICAL RESULTS ASNO-081110-001 (GRAB) DEPTH 10’ BGS ANALYTES: ND
DENSE VEGETATION
ASNO-081110-002 (GRAB) DEPTH 5’ BGS ANALYTES: ND ASNO-081110-002 (GRAB)
ASNO-081110-001 (GRAB)
ASNO-081110-003 COMPOSITE
ASNO-081110-003 (GRAB) DEPTH 1’ BELOW TOP OF PILE ANALYTES: TOTAL EFH DRO: 7.17 mg/kg FLUORENE: 0.007 mg/kg
LEGEND PUMP HOUSE/GENERATOR BUILDING
DENSE VEGETATION
DAY TANK FUEL PIPING EXCAVATED AREA
UNPAVED ROAD
UST LOCATION SOIL STOCKPILE FENCE
CONCRETE SLAB
DENSE VEGETATION
N
0
apec allied pacific environmental consulting
APPROXIMATE SCALE 12.5 25 FEET
TITLE: SITE PLAN INDICATING SAMPLE LOCATIONS AND ANALYTICAL RESULTS PROJECT: AS NAMO UST CLOSURE REPORT
FIGURE: 3
UNDERGROUND STORAGE TANK CLOSURE REPORT FOR 500-GALLON DIESEL FUEL TANK AT GUAM WATERWORKS AUTHORITY ASAN SEWER PUMP STATION (GWA CD4) ASAN, GUAM
June 2011
Prepared for: Guam Environmental Protection Agency 17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
Prepared by:
apec allied pacific environmental consulting P.O. BOX 5091 AGANA, GUAM 96932 T 671.477.7310/12 | F 671.477.7311 | apecguam@guam.net
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Guam EPA, UST Closure Report GWA Asan Sewer Pump Station, 500 G, Asan, Guam June 2011
1.0 EXECUTIVE SUMMARY Introduction This report documents the proceedings of a subsurface site investigation for the closure of an Underground Storage Tank. APEC conducted soil investigation activities at the location of a 500 gallon underground storage tank (UST) at the Guam Waterworks Authority (GWA), Asan Sewer Pump Station, Asan, Guam in August 2010. GWA supervisors indicated that a UST system was never employed at this site. However, initial notification form was on file for a 500-gallon UST located at the Asan site. Confirmation soil sampling was conducted on 23 August 2010. Olfactory, PID screening and confirmation soil sample analytical results indicate low to non-detectable concentrations of petroleum hydrocarbons and VOCs in soil samples collected during this investigation. No potential impacts to groundwater were revealed as a result of field screening or laboratory analytical testing. Sequence of UST Closure Activities Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an enclosure to this report. The location of the UST was undocumented prior to APEC’s investigation. As a result, APEC conducted underground locator survey using metal detector on 20 August 2010. Based on the findings, the probable location of the UST was determined and soil excavation was conducted on 23 August 2010. Soil samples were collected for confirmation analysis on 23 August 2010. Following the direction and under the supervision of Guam EPA, APEC personnel backfilled the excavation area on 23 August 2010. Site Investigation Activities Site investigation activities consisted of visual, olfactory and PID field screening and laboratory analytical soil testing for the following analytes: 1) Total Extractable Fuel Hydrocarbons (EFH) by EPA Method 8015B, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270C and 3) Benzene, Toluene, Ethylbenzene, Total Xylenes by EPA Method 8260B. Field Screening and Soil Sample Analytical Results Visual, olfactory, PID screening and confirmation soil analytical results do not indicate levels of petroleum hydrocarbon contamination above project clean-up goals. Site Conceptual Model The site conceptual model is based on field observations, geological and hydrological conditions and laboratory analytical testing performed on environmental media collected at the site. Elevations within the perimeter fence of the site range from approximately 7ft – 8ft above MSL. The slope within the perimeter fence of the site is 0.01ft per foot (1% slope) and is visibly flat. The elevation at the site of the UST excavation pit is approximately 4ft above MSL. Approximately fifty-percent (50%) of the site is covered by impervious surfaces including buildings, concrete footings, and pavement. The remaining undeveloped areas of the site are vegetated with grass. The undeveloped portions of the property absorb a portion of the stormwater run-off from the site. Storm water drains from the nearby rooftop of the generator building associated with the subject UST through a vertical conduit onto the grassy surface near the location of the UST. Depth to groundwater at the location of the UST excavation is approximately 7 - 8 ft below ground surface. Groundwater at the site is brackish water as freshwater and seawater are significantly mixed due to tidal influences. No significant drinking water sources exist within 1000 feet of the facility. The prevailing groundwater flow is generally to the north-northwest towards the Philippine Sea. Subsurface porosities in the vicinity of the site are mixed due to the heterogeneous nature of the artificial fill that has been deposited in the area. Hydraulic conductivities in the artificial fill materials are estimated to be low to moderate within the vicinity of the site.
1 of 10
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Guam EPA, UST Closure Report GWA Asan Sewer Pump Station, 500 G, Asan, Guam June 2011
Verification of Site Conceptual Model The presence of the 500-gallon UST was not verified during this investigation. Excavation activities at the probable location of the UST (based on metal detector survey) showed no indication of a UST system. Diesel Range Organics and BTEX compounds were not detected above laboratory reporting limits in the soil samples collected during this investigation. A soil sample collected from the excavation pit at a depth of 8.0 feet bgs contained detections of Benzo (b) fluoranthene (0.00754 mg/kg) and Pyrene (0.00721 mg/kg). The soil sample collected from the third excavation pit contained a detection of Benzo (b) fluoranthene at a concentration of 0.00721 mg/kg). All analytes tested in soil samples were below project soil screening thresholds. Conclusions and Recommendations Based on these findings it is evident that minor impacts exist in soil below regulatory screening thresholds in the area of the location of former UST and associated piping. Future release of fuel form this location has been prevented by the removal of the piping and its associated UST. Based on a review of the evidence presented within this UST closure report it is recommended that no further action be considered at the site.
2 of 10
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ASAN UST SITE LOCATION
N
TITLE: MAP OF GUAM, INDICATING SITE LOCATION
apec allied pacific environmental consulting
PROJECT: ASAN UST CLOSURE REPORT
FIGURE: 1
0
APPROXIMATE SCALE 0.25 0.5 MILES
N
ASAN UST SITE LOCATION
apec
TITLE: PROJECT STIE VACINITY MAP
allied pacific environmental consulting
PROJECT: ASAN UST CLOSURE REPORT 2000 USGS
FIGURE: 2
BUILDING
ANALYTICAL RESULTS
UNPAVED AREA
N
ASAN082310001 (GRAB) BUILDING DEPTH 8’ BGS ANALYTES: NOT DETECTED ABOVE REGULATORY LIMIT
GENERATOR BUILDING HEAVY VEGETATION ASAN082310002 (8 FT BGS)
ASAN082310002 (GRAB) DEPTH 8’ BGS ANALYTES: NOT DETECTED ABOVE REGULATORY LIMIT
MAIN SPS BUILDING EXCAVATED AREAS
ASAN082310003 (8 FT BGS)
ASAN082310003 (GRAB) DEPTH 8’ BGS ANALYTES: NOT DETECTED ABOVE REGULATORY LIMIT
ASAN082310001 (8 FT BGS) 250GALLON AST
BUILDING
0
APPROXIMATE SCALE 10 20 FEET
apec
TITLE: SITE LAYOUT WITH ANALYTICAL DATA
allied pacific environmental consulting
PROJECT: ASAN UST CLOSURE REPORT
FIGURE:3
UNDERGROUND STORAGE TANK CLOSURE REPORT FOR 350-GALLON DIESEL FUEL TANK (GWA BARRIGADA) AT GUAM WATERWORKS AUTHORITY BARRIGADA SEWAGE PUMPING STATION BARRIGADA, GUAM
March 2011
Prepared for: Guam Environmental Protection Agency 17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
Prepared by:
apec allied pacific environmental consulting P.O. BOX 5091 AGANA, GUAM 96932 T 671.477.7310/12 | F 671.477.7311 | apecguam@guam.net
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Guam EPA, UST Closure Report GWA Barrigada Sewer Pumping Station, 350 G, Barrigada, Guam March 2011
1.0 EXECUTIVE SUMMARY Introduction APEC conducted soil investigation activities related to a 350 gallon underground storage tank (UST) at the Guam Waterworks Authority (GWA), Barrigada Sewage Pumping Station, Barrigada, Guam in August 2010. Confirmation soil sampling was conducted on 04 August 2010. Olfactory, PID screening and confirmation soil sample analytical results indicate low to non-detectable concentrations of petroleum hydrocarbons in soil samples collected during this investigation. No potential impacts to groundwater were revealed as a result of field screening or laboratory analytical testing. Sequence of UST Closure Activities Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an enclosure to this report. Location of the UST was undocumented prior to APEC’s investigation. As a result, APEC conducted underground locator survey using a metal detector on 27 July 2010. Based on the findings, the probable location of the UST was determined and asphalt-slab demolition was conducted on 04 August 2010. Soil excavation was conducted on 04 August 2010. Soil samples were collected for confirmation analysis on 04 August 2010. Following the direction and under the supervision of Guam EPA, APEC personnel backfilled the excavation area on 04 and 05 August 2010. Site Investigation Activities Site investigation activities consisted of visual, olfactory and PID field screening and laboratory analytical soil testing for the following analytes: 1) Total Extractable Fuel Hydrocarbons (EFH) by EPA Method 8015B, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270C and 3) Benzene, Toluene, Ethylbenzene, Total Xylenes by EPA Method 8260B. Field Screening and Soil Sample Analytical Results Visual, olfactory, PID screening and confirmation soil analytical results do not indicate levels of petroleum hydrocarbon contamination above project clean-up goals. Site Conceptual Model The site conceptual model is based on field observations, geological and hydrological conditions and laboratory analytical testing performed on environmental media collected at the site. Elevations within the perimeter fence of the site range from approximately 196ft – 198ft above MSL. The slope within the perimeter fence of the site is 0.01ft per foot (1% slope) and is visibly flat. The elevation at the site of the UST excavation pit is approximately 196ft above MSL. Approximately fifty-percent (50%) of the site is covered by impervious surfaces including buildings, concrete footings, and pavement. The remaining undeveloped areas of the site are vegetated with grass. The undeveloped portions of the property absorb a portion of the stormwater run-off from the site. Storm water drains from the nearby building rooftops of the site through a vertical conduit onto the grass vegetated area near the perimeter of the buildings. There was no evidence of significant releases of fuel product during the site investigation. Depth to groundwater at the location of the UST excavation is approximately 191-193 ft below ground surface. Groundwater located in the vicinity of the site is available for extraction as drinking water. Guam Waterworks Authority drinking water supply well A-15 is located approximately 700 feet to the northnortheast of the site. The prevailing groundwater flow is generally to the west-northwest towards Agana Bay. Limestone porosities in the vicinity of the site are mixed due to the argillaceous nature of subsurface. Hydraulic conductivities in the argillaceous materials are estimated to be moderate within the vicinity of the site. Verification of Site Conceptual Model The presence of the 350-gallon UST was not verified during this investigation. Excavation activities at the probable location of the UST (based on metal detector survey) showed no indication of a UST system. A soil sample collected from the excavation pit at a depth of 3.5 feet bgs contained Diesel Range Organics (DRO) at a concentration of 4.81 mg/kg (ppm). At a depth of 9 feet bgs, soil sample analytical results do 1 of 10
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Guam EPA, UST Closure Report GWA Barrigada Sewer Pumping Station, 350 G, Barrigada, Guam March 2011
not indicate the presence of DRO or any other analyte of concern above the laboratory reporting limit. The composite soil sample from the excavation stockpile contained DRO at a concentration of 9.75 mg/kg. All other analytes tested in soil samples collected during this investigation were found to be below laboratory detection limits. Conclusions and Recommendations Based on these findings it is evident that the soil beneath the excavated area is not heavily impacted by constituents of concern related to a release of petroleum hydrocarbons. Verbal communications from Guam EPA indicates that the UST system was replaced by an above ground storage tank in June 2001. Based on this information, including the findings of low to non-detectable concentrations of petroleum fuel hydrocarbons and VOCs in soil it is anticipated that no further action is necessary at the subject site.
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BARRIGADA UST SITE LOCATION
N
TITLE: MAP OF GUAM, INDICATING SITE LOCATION
apec allied pacific environmental consulting
PROJECT: BARRIGADA UST SITE INVESTIGATION
FIGURE: 1
BARRIGADA UST SITE LOCATION
N APPROXIMATE SCALE
0
apec
TITLE: PROJECT SITE VICINITY MAP.
allied pacific environmental consulting
PROJECT: BARRIGADA UST SITE INVESTIGATION MAP COURTESY OF UNITED STATES GEOLOGICAL SERVICE, 1999
0.5
1
MILES
Figure: 2
ANALYTICAL RESULTS BAR080410-001 (GRAB) DEPTH 3.5’ BGS TIME 12:10 ANALYTES: DRO 4.81 mg/kg
FENCELINE
BAR080410-002 (GRAB) DEPTH 9’ BGS TIME 14:40 ANALYTES: ALL, ND
PUMP STATION AST
BAR080410-003 (COMPOSITE) DEPTH 1’ BGS TIME 16:28 ANALYTES: DRO 9.75 mg/kg
OLD GENERATOR PAD SIX INCHES TOP SOIL ABOVE CONCRETE SLAB
COMPOSITE SAMPLES LOCATIONS
SOIL STOCK PILE GENERATOR BUILDING
BAR080410-003 (COMPOSITE) DEPTH 1’ BGS
GATE
GATE EXCAVATED AREA
GRAB SAMPLE LOCATIONS BAR080410-001 (GRAB), DEPTH 3.5’ BGS BAR080410-002 (GRAB), DEPTH 9’ BGS
APPROXIMATE SCALE FEET 0
apec allied pacific environmental consulting
12.5
TITLE: SITE PLAN INDICATING SAMPLE LOCATIONS AND ANALYTICAL RESULTS PROJECT: BARRIGADA UST SITE INVESTIGATION
FIGURE: 3
25
UNDERGROUND STORAGE TANK CLOSURE REPORT FOR GWA MAMAJANO SEWAGE PUMP STATION UST-001(1,200gallon) AND UST-002 (PREVIOUSLY REMOVED) AT GUAM WATERWORKS AUTHORITY MAMAJANO SEWAGE PUMPING STATION TAMUNING, GUAM
March 2011
Prepared for: Guam Environmental Protection Agency 17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
Prepared by:
apec lallied pacific environmental consulting
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P.O. BOX 5091 AGANA, GUAM 96932 T: 671.477.7310/12 | F: 671.477.7311 | apecguam@guam.net
Guam EPA, UST Closure Report GWA Mamajano Sewer Pumping Station UST-001 and UST-002 Tamuning, Guam March 2011
1.0 EXECUTIVE SUMMARY Introduction A 1,200-gallon steel underground storage tank (UST-001) was removed from the Guam Waterworks Authority (GWA), Mamajano Sewage Pumping Station (MSPS), Tamuning, Guam in July 2010. Additional investigation activities were conducted at the location of former UST-002 located at the eastern section of the property. Confirmation soil sampling was conducted on 8 July 2010. Olfactory, PID screening and confirmation soil sampling analytical results indicate minor petroleum hydrocarbon impacts to the soil below the product piping and the soil immediately underlying the UST cavity. No significant impacts to groundwater were revealed as a result of this investigation. Sequence of UST Closure Activities Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an enclosure to this report. The concrete-slab demolition was conducted on 7 July 2010. Liquid tank contents were removed and disposed of on 7 July 2010. UST sidewall soil excavation was conducted on 8 July 2010. The UST and associated piping was removed from the site on 8 July 2010 and properly disposed of and recycled on 6 August 2010. Soil samples were collected for confirmation analysis on 8 July 2010. Following the direction and under the supervision of Guam EPA, APEC personnel backfilled the excavation area on 8 July 2010. Site Investigation Activities Site investigation activities consisted of visual, olfactory and PID field screening and laboratory analytical soil testing for the following analytes: 1) Total Extractable Fuel Hydrocarbons (EFH) by EPA Method 8015B, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270C and 3) Benzene, Toluene, Ethylbenzene, and Total Xylenes by EPA Method 8260B. Field Screening and Soil Sample Analytical Results Visual, olfactory, PID screening and confirmation soil analytical results indicate levels of petroleum contamination above project clean-up goals in samples collected from the bottom of the northwestern end of the tank cavity and below the fuel piping of the UST. Site Conceptual Model The site conceptual model is based on field observations and laboratory analytical testing performed on environmental media collected at the site and the geological and hydrological conditions at the site. Elevations within the perimeter fence of the site range from approximately 79 – 83 feet above mean sea level (MSL). The slope within the perimeter fence of the site is 0.04ft per foot (4% slope) and is visibly flat. The elevation at the site of the UST excavation cavity is approximately 80ft above MSL. Approximately sixty-percent (60%) of the site is covered by impervious surfaces including buildings, concrete footings, and pavement. The remaining areas are vegetated with grass. The undeveloped portions of the property absorb a portion of the stormwater run-off from the site. Storm water from the rooftop of the building (in closest proximity to the UST) is directed through down-pipes to the surrounding pavement and grassy vegetated areas. Depth to groundwater at the location of the UST excavation is approximately 77 ft below ground surface. No significant drinking water sources exist within 1000 feet of the facility. The prevailing groundwater flow is generally to the north-northwest towards the Philippine Sea. Limestone porosities in the vicinity of the site are moderate. Hydraulic conductivities in the artificial fill materials are estimated to be low to moderate within the vicinity of the site. Verification of Site Conceptual Model The fuel line leading between the UST-001 and the associated day tank was corroded and noticeably leaking. APEC field personnel observed liquid leaking from a corroded fitting upon excavating the trenching for the fuel line. The soil in the area of the broken fuel line was observed by environmental technicians who noted olfactory and PID test evidence of contamination. The laboratory analytical results 1 of 11
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Guam EPA, UST Closure Report GWA Mamajano Sewer Pumping Station UST-001 and UST-002 Tamuning, Guam March 2011
for soil obtained from 1.5 ft below the leaking fuel line indicated levels of Total Extractable Fuel Hydrocarbons of 160 mg/kg (ppm). Petroleum hydrocarbons odor was observed by field personnel during UST excavation activities and confirmed by PID readings. Upon removing the tank from the excavation cavity, a leak was observed at the bottom of the tank. A soil sample collected from the northwestern extent of the tank cavity at 8 feet bgs contained EFH concentrations of 190 mg/kg. At the southeastern extent of the tank cavity, laboratory analytical results indicate the presence of EFH at a concentration of 16 mg/kg from the soil sample collected at 8 feet bgs. Additional investigation at the location of a former UST (referenced herein as UST-002) along the eastern section of the subject site was conducted by APEC on 8 July 2010. Soil sample analytical results indicate the presence of EFH at a concentration of 260 mg/kg at a depth of 8.5 feet bgs at this location. All other analytes tested in soils obtained at the site were found to be below regulatory limits. Conclusions and Recommendations Based on these findings it is evident that minor impacts exist in the area of the location of the corroded, leaking fuel pipe fitting and the associated UST-001. Additionally, concentrations of EFH were detected above the regulatory limit in soil samples collected from the excavation of the former UST-002 along the eastern portion of the site. Future release of fuel from the UST-001 location has been prevented by the removal of the fuel line and its associated UST. Future releases of fuel from the UST-002 location are not anticipated as the former UST and fuel lines were previously removed. Based on this evidence, it is recommended that the Guam EPA consider potential remedial actions at the location UST and associated piping, as an option, a 12-month period of monitored natural attenuation complemented by one scheduled round of soil sampling and analysis to verify the reduction of petroleum hydrocarbons at the end of the remediation period.
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MAMAJANO UST SITE LOCATION
N
TITLE: MAP OF GUAM, INDICATING SITE LOCATION
apec allied pacific environmental consulting
PROJECT: MAMAJANO UST CLOSURE REPORT
FIGURE: 1
ONE MILE RADIUS
MAMAJANO UST SITE LOCATION
N APPROXIMATE SCALE 0
apec allied pacific environmental consulting
1000
FEET 4000
2000
TITLE: TOPOGRAPHIC MAP OF SITE VACINITY PROJECT: MAMAJANO UST CLOSURE REPORT Map Courtesy of United States Geological Services, 1978
FIGURE: 2
MARINE CORPS DRIVE (SB) ANALYTICAL DATA MAM070870001 (GRAB) DEPTH 8’ BGS ANALYTES: N/A
MEDIAN
ONE MILE RADIUS MAM070870002 (GRAB) DEPTH 8’ BGS ANALYTES: Total EFH: 190 mg/Kg
MARINE CORPS DRIVE (NB) BUILDING MAM070810004
MAM070870003 (GRAB) DEPTH 1.5’ BGS ANALYTES: Total EFH: 160 mg/Kg
MAM070870004 (GRAB) DEPTH 8.5’ BGS ANALYTES: Total EFH: 260 mg/Kg
BUILDING
MAM070810002
EXCAVATED AREA
MAM070810001
GENERATOR
NOTE: ANALYTES REPORTED HERE ARE ABOVE SCREENING LEVELS
VEGETATED AREA MAM070810003
EXCAVATED AREA
POWER POLE
PARKING LOT
CEMENT WALL (APPROX 2 FT HIGH)
APPROXIMATE SCALE BUILDING
0
apec
TITLE: SITE PLAN INDICATING SAMPLE LOCATIONS AND ANALYTICAL RESULTS
allied pacific environmental consulting
PROJECT: MAMAJANO UST CLOSURE REPORT
10
FEET 20
FIGURE: 3
UNDERGROUND STORAGE TANK CLOSURE REPORT FOR 1,000-GALLON DIESEL FUEL TANK (GWA PAGO BAY) AT GUAM WATERWORKS AUTHORITY PAGO BAY SEWER PUMP STATION CHALAN PAGO, GUAM
June 2011
Prepared for:
Guam Environmental Protection Agency
17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
Prepared by:
apec allied pacific environmental consulting P.O. BOX 5091 AGANA, GUAM 96932 T 671.477.7310/12 | F 671.477.7311 | apecguam@guam.net
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Guam EPA, UST Closure Report GWA Pago Sewer Pump Station (Pago), 1,000 Gal June 2011
1.0 EXECUTIVE SUMMARY 1.1 Introduc tion Investigation activities rela ting to a 1,000-g allon carbon ste el un derground storage tan k (UST) were conducted at the Guam Waterworks Authority (G WA), Pago Bay Sewer Pump Station (PBSPS), Chalan Pago, Gu am in Septem ber 2 010. Th e UST wa s previously re moved a nd t ransported from the site. Historical photographs indicate the UST was remove d from the site on 21 Ju ne 2006. Confi rmation soil sampling was conducted on 02 September 2010. Olfactory, PID screening and confirmation soil sample analytical results indicate petroleum hydrocarbon impacts to the soil below the former UST. 1.2 Sequence of UST Closure Activities Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an enclosure to this re port. T he ground-surface demolition and soil excav ation was conducted at the location of the forme r US T on 02 Sep tember 2 010. Soil and sa mples were collected fo r confirmatio n analysis on 02 September 2010. Fo llowing the direction and under the supervision of Guam EPA, APEC personnel backfilled the excavation area on 02 September 2010. 1.3 Site Investigation Activities Site investigation activities consisted of visual, olfactory and PID fi eld screening and laboratory analytical soil testing for the followi ng analytes: 1) Total Extr actable Fuel Hydrocarbons (EF H) by EPA Method 8015B, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270C and 3) Benzene, Toluene, Ethylbenzene, and Total Xylenes (BTEX, collectively) by EPA Method 8260B. 1.4 Field Screening and Soil Sample Analytical Results Visual, olfact ory, PID screenin g and confirmation soil analytical result s indi cate level s of petroleum hydrocarbon contamination an order of magnitude above project clean-up goals at the western end of the former UST tank cavity. 1.5 Site Conceptual Model The site conceptual model is ba sed upon field ob servations and laboratory analytical testing performed on environmental media collected at the site and the geological and hydrological conditions at the site. Elevations within the pe rimeter fence of the site range from approximately 14ft – 17ft above MSL. The slope within t he perimeter fence of the site is a pproximately 0.025ft per foot (2. 5% slope) and is visibly flat. The elevation at the site of the UST excavation pit is approximately 15ft above MSL. Approximately fifty five percent (55%) of the site i s covered by impervio us su rfaces in cluding buildings, concrete footings, an d pavement. The re maining undevel oped ar eas of the site a re v egetated with gra ss. Th e undeveloped portions of the property absorb a portion of the stormwater run-off from the site. Depth to groundwater at the location of the US T excavation i s approximate ly 9-11 ft be low g round surface. Gro undwater at the site is b rackish water a s fre shwater and sea water are sig nificantly mixed due to tidal influen ces. No drin king water sou rces e xist within 10 00 feet of the facility. Th e prevailin g groundwater flow is generally to the southeast towards the Pacific Ocean. Subsurface porosities in the vicinity of the site are low to moderate. Hydraulic conductivities in the subsurface materials are estimated to be low to moderate within the vicinity of the site. 1.6 Verification of Site Conceptual Model Field activities conducted during this investigation confirmed prior removal of t he UST. Corroded piping associated with the UST was found by APEC personnel in the overburden soil of the former tank cavity 1
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Guam EPA, UST Closure Report GWA Pago Sewer Pump Station (Pago), 1,000 Gal June 2011
and appeared to be used as backfill by the previous contractor. The soil below the former tank cavity was noted to exhibit olfactory and PID test evidence of TP H contamination. Laboratory analytical results for soil obtained from 8ft bgs beneath the easte rn and western ends of the forme r UST indi cated levels of Total Extract able Fuel Hydrocarbons of 832 mg/kg (ppm) and 79.4 mg/kg, respectively. No other constituents of concern were detected above laboratory detection limits for the sampl es submitted during this inve stigation. See S ection 4.3, T able 2, fo r a pplicable U.S. EPA Region IX, Regional Screening Levels, May 2010. 1.7 Conclusions and Recommendations Based upon these findings it is evident that diesel-im pacted soil exists beneath the location of the former UST. Potential for future fuel release at this location was previously prevented by the removal of the UST and a ssociated fuel lin es. A potential reme dial a ction at the lo cation of the petrol eum h ydrocarbon impacted soil might in clude, a s an option, a 12-month period of mo nitored natu ral attenuatio n complemented by one scheduled round of soil sampl ing and analysis to verify the reduction of petroleum hydrocarbons at the end of the remediation period.
2
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PAGO BAY UST SITE LOCATION
apec allied pacific environmental consulting
TITLE: MAP OF GUAM INDICATING PROJECT SITE LOCATION PROJECT: PAGO BAY UST SITE INVESTIGATION
FIGURE: 1
PAGO BAY UST SITE LOCATION
0
apec
TITLE: PROJECT SITE VICINITY MAP
allied pacific environmental consulting
PROJECT: PAGO BAY UST CLOSURE REPORT 2000 USGS
APPROXIMATE SCALE 0.5 1.0 MILES
FIGURE: 2
ANALYTICAL DATA
VEGETATION
PAG0090210001 (GRAB) DEPTH 8’ BGS TIME 11:25 ANALYTES: EFH: (832 mg/kg) BTEX: ND PAHs: ND
ROAD
PAG0090210002 (GRAB) DEPTH 8’ BGS TIME 11:55 ANALYTES: EFH: (832 mg/kg) BTEX: ND PAHs: ND
PUMP HOUSE
UNPAVED AREA
PAG0090210002 8’BGS GENERATOR BUILDING
EXCAVATED AREA
PAG0090210001 8’BGS
0
apec
TITLE: PAGO BAY UST SITE LAYOUT
allied pacific environmental consulting
PROJECT: PAGO BAY UST CLOSURE REPORT
APPROXIMATE SCALE 12.5 25
FIGURE: 3
FEET
UNDERGROUND STORAGE TANK CLOSURE REPORT FOR 6,000-GALLON DIESEL FUEL TANK (GWA PASEO) AT GUAM WATERWORKS AUTHORITY AGANA MAIN SEWAGE PUMPING STATION HAGATNA, GUAM
January 2010
Prepared for:
Guam Environmental Protection Agency
17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
Prepared by:
apec allied pacific environmental consulting P.O. BOX 5091 AGANA, GUAM 96932 T 671.477.7310/12 | F 671.477.7311 | apecguam@guam.net
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Guam EPA, UST Closure Report GWA Agana Main Sewer Pumping Station (Paseo), 6,000Gal January 2010
1.0 EXECUTIVE SUMMARY 1.1 Introduction A 6,000-gallon fiberglass reinforced plastic (FRP) underground storage tank (UST) was removed from the Guam Waterworks Authority (GWA), Agana Main Sewage Pumping Station (AMSPS), Hagatna, Guam i n June 2010. Confirmation groundwater and soil sampling was conducted on 30 June 2010. Olfactory, PID screening a nd confi rmation soil sampl e analytical results indi cate minor p etroleum imp acts to the soil below the pi ping of the UST. No significant imp acts to g roundwater were revealed as a result of fiel d screening or groundwater laboratory analytical testing. 1.2 Sequence of UST Closure Activities Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an en closure to this re port. The co ncrete-slab demolition wa s co nducted on 28 Ju ne 2010. Liquid tank contents were remov ed an d dispo sed of on 2 9 Ju ne 20 10. A Certified I ndustrial Hygienist (CIH) provided Ga s-Free Certification on 30 June 2 010. UST side wall soil ex cavation wa s conducted o n 2 9 and 30 June 2010. The UST and associated piping was removed from the site and properly disposed or recycled on 30 June 2010. Soil and g roundwater samples were collected for confirmation analysis on 30 June 2010. Following the direct ion and under the supervision of Guam EPA, APEC personnel backfilled the excavation area on 1 July 2010. 1.3 Site Investigation Activities Site investigation activities consisted of visual, olfactory and PID fi eld screening and laboratory analytical soil testing for the followi ng analytes: 1) Total Extr actable Fuel Hydrocarbons (EF H) by EPA Method 8015B, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270C and 3) Benzene, Toluene, Ethylbenzene, Xylene by EPA Method 8260B. 1.4 Field Screening and Soil Sample Analytical Results Visual, olfact ory, PID screenin g and confirmation soil analytical result s indi cate level s of petroleum contamination an order of magnitude above project clean-up goals at the site of the fuel piping associated with the subj ect UST. La boratory analytical results for groundwater samples collected below the site of the former UST indicate levels below regulatory threshold values. 1.5 Site Conceptual Model The site conceptual model is ba sed upon field ob servations and laboratory analytical testing performed on environmental media collected at the site and the geological and hydrological conditions at the site. Elevations within the pe rimeter fence of the site range from approximately 11ft – 12ft above MSL. The slope within the perimeter fence of the site is 0.03ft per foot (3% slope) and is visibly flat. The elevation at the site of the UST excavation pit is approximately 11ft above MSL. Approximately fifty-percent (50%) of the site is covered by imp ervious surfa ces in cluding building s, concrete footi ngs, a nd pav ement. Th e remaining u ndeveloped areas of the si te are veget ated with g rass. The un developed p ortions of the property a bsorb a portion of the sto rmwater run -off from the site. Storm wa ter d rains f rom the nearby rooftop of th e gene rator building associated with t he su bject UST throug h a vertical conduit onto th e grassy surface within 9 feet of the location of the UST. One of the two fuel lines leading between the UST and the associated diesel powered electric generator was observed to be heavily corroded. The fuel lin e was observed to be sep arated at the location of he aviest corrosion at approxi mately 2 inch es bgs. The corroded fuel line was located within 24 inches of t he associated building’s vertical stormwater drainage conduit. Site technicians observed residual amounts of fuel contained in the separated fuel line. Depth to groundwater at the location of the UST excavation is approximately 11 ft below ground surface. Groundwater at the site is brackish water as freshwater and seawater is significantly mixed due to tidal influences. No d rinking water sources exist within 1000 feet of the facility. The p revailing groundwater flow is generally to the north-northwest towards the Philippine Sea. Sub surface porosities in the vi cinity of the site are mixed d ue to the hete rogeneous nature of the a rtificial fill that has been deposited in the 1
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Guam EPA, UST Closure Report GWA Agana Main Sewer Pumping Station (Paseo), 6,000Gal January 2010
area. Hydraulic conductivities in the artificial fill materials are estimated to be moderate within the vicinity of the site. 1.6 Verification of Site Conceptual Model One of the two fuel line s leading bet ween the US T and the asso ciated die sel-electric ge nerator was heavily corro ded an d se parated at ap proximately 2 in ches b gs. The broke n fuel line st ill contain ed residual amounts of fuel and wa s located within 24 i nches of the associated buildings vertical stormwater drainage conduit. The soil in the area of the separated fuel line was noted to exhibit olfactory and PID test evidence of TPH contami nation. The laboratory a nalytical results for soil obt ained f rom 4ft below th e heavily corro ded fuel line indicated levels of Total Extractable F uel Hydrocar bons of 373 mg/kg (ppm). The la boratory analytical results fo r groundwater o btained from 11ft bg s and do wn gradi ent from the corroded fuel line indicated levels of To tal Extractable Fuel Hydrocarbons of 0.83 mg/kg (ppm). All other analytes tested in groundwater and soils obtained at the site were found to be below regulatory limits, see Section 4.4, Table 3, for applicable U.S. EPA Region IX, Regional Screening Levels, May 2010. 1.7 Conclusions and Recommendations Based u pon these findin gs it is eviden t that a sma ll quantity (ap proximately 2 cubi c yard s) of dieselimpacted soil exists in the immediate a rea of the lo cation of the corrod ed a nd sep arated fuel line. In addition, the re are n o si gnificant imp acts to g roundwater at the site. Future release of fuel from this location has been prevented by the removal of the remaining fuel, the fuel line and its associated UST. A potential remedial action at the location of the corroded and separated fuel line might include a 12-month period of mo nitored natural attenuatio n com plemented by one scheduled round of soil sampling and analysis to verify the reduction of petroleum hydrocarbons at the end of the remediation period.
2
apec
P.O. BOX 5091, HAGATNA, GUAM 96932 | TEL. 671.477.7310/12/14 | FAX 671.477.7311 | apecguam@ guam.net
Red arrow indicates location of project site
N
apec
SHEET TITLE: MAP OF GUAM INDICATING SITE LOCATION
allied pacific environmental consulting
PROJECT: GEPA, GWA, AMSPS, (PASEO) UST CLOSURE REPORT
FIGURE: 1
1-MAP-INCH = 1600 FEET
N MARINE CORPS DRIVE (ROUTE 1)
PASEO DE SUSANA PARK PROJECT SITE
apec
SHEET TITLE: PROJECT VICINITY
allied pacific environmental consulting
PROJECT: GUAM EPA, GUAM WATERWORKS AUTHORITY, AGANA MAIN SEWAGE TRASFER PUMP STATION, (PASEO) UST CLOSURE REPORT
FIGURE: 2
ANALYTES DETECTED
(Note: Analytes above regulatory limits in bold red)
001
002
GENERATOR HOUSE
TANK BED EXCAVATION
PIPE RUN EXCAVATION CONCRETE TANK VAULT
RESULTS
mg/l (groundwater)
SAMPLE ID
PASEO-063010-001
TOTAL EXTRACTABLE FUEL HYDROCARBONS
0.83
TOTAL POLYNUCLEAR AROMATIC HYDROCARBONS
ND (<0.48 ug/l)
RESULTS
mg/kg (soil)
SAMPLE ID
PASEO-063010-002
TOTAL EXTRACTABLE FUEL HYDROCARBONS
373
TOLUENE
0.0033
TOTAL XYLENES
0.014
FLUORANTHENE
0.130
PHENANTHRENE
0.220
PYRENE
0.130
OVERBURDEN SOIL PILE
LEGEND
N
LOCATION OF FUEL PIPE PID Test at location -001: 0.0 ppm PID Test at location -002: 10.7 ppm
LOCATION OF TANK VENT PIPE SAMPLE I.D. AND LOCATION 002 ROOF STORMWATER DRAINAGE PIPE TANK FILL PIPE
1-MAP-INCH = 9 FEET
PERIMETER FENCELINE
100 FT TO AGANA BOAT BASIN (MARINA)
apec
SHEET TITLE: SITE DETAIL DIAGRAM
allied pacific environmental consulting
PROJECT: GUAM EPA, GUAM WATERWORKS AUTHORITY, AGANA MAIN SEWAGE TRASFER PUMP STATION, (PASEO) UST CLOSURE REPORT
FIGURE: 3
UNDERGROUND STORAGE TANK CLOSURE REPORT FOR 350-GALLON DIESEL FUEL TANK AT GUAM WATERWORKS AUTHORITY PITI (CD-3) SEWER PUMP STATION PITI, GUAM
June 2011
Prepared for: Guam Environmental Protection Agency 17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
Prepared by:
apec allied pacific environmental consulting P.O. BOX 5091 AGANA, GUAM 96932 T 671.477.7310/12 | F 671.477.7311 | apecguam@guam.net
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Guam EPA, UST Closure Report GWA Piti Sewer Pump Station (CD-3), 350 G, Piti, Guam June 2011
1.0 EXECUTIVE SUMMARY 1.1 Introduction APEC conducted soil investigation activities related to 350 gallon underground storage tank (UST) at the Guam Waterworks Authority (GWA), Piti Sewer Pump Station (CD-3), Piti, Guam in August 2010. Confirmation soil and groundwater sampling was conducted on 25 August 2010. Potential impacts to groundwater were revealed as a result of water sample laboratory analytical testing. 1.2 Sequence of UST Closure Activities Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an enclosure to this report. Location of the UST was undocumented prior to APECâ&#x20AC;&#x2122;s investigation. As a result, APEC conducted underground locator survey using metal detector on 20 August 2010. Based on the findings, the probable location of the UST was determined and soil excavation was conducted on 25 August 2010. Soil samples were collected for confirmation analysis on 25 August 2010. Following the direction and under the supervision of Guam EPA, APEC personnel backfilled the excavation area on 25 August 2010. 1.3 Site Investigation Activities Site investigation activities consisted of visual, olfactory and PID field screening and laboratory analytical soil testing for the following analytes: 1) Total Extractable Fuel Hydrocarbons (EFH) by EPA Method 8015B, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270C and 3) Benzene, Toluene, Ethylbenzene, Total Xylenes by EPA Method 8260B. 1.4 Field Screening and Soil and Water Sample Analytical Results Visual, olfactory, PID screening and confirmation soil analytical results do not indicate levels of petroleum hydrocarbon contamination above project clean-up goals in soil. Confirmation water sample analytical results indicated 817 ug/L total petroleum hydrocarbons as diesel range organics. This value is above the regulatory screening threshold of 50 ug/L. Detections of several PAHs in the groundwater sample were also above regulatory thresholds. Refer to Tables 1 and 2 for tabulated results from soil and groundwater sampling. 1.5 Site Conceptual Model The site conceptual model is based on field observations, geological and hydrological conditions and laboratory analytical testing performed on environmental media collected at the site. Elevations within the perimeter fence of the site range from approximately 5ft â&#x20AC;&#x201C; 8ft above MSL. The slope within the perimeter fence of the site is 0.03ft per foot (3% slope) and is visibly flat. The elevation at the site of the UST excavation pit is approximately 8ft above MSL. Approximately sixty five-percent (65%) of the site is covered by impervious surfaces including buildings, concrete footings, and pavement. The remaining undeveloped areas of the site are vegetated with grass. The undeveloped portions of the property absorb a portion of the stormwater run-off from the site. Storm water drains from the nearby rooftop of the generator building associated with the subject UST through a vertical conduit onto the grassy surface near the location of the UST. Depth to groundwater at the location of the UST excavation is approximately 8ft below ground surface. Groundwater at the site is brackish water as freshwater and seawater is significantly mixed due to tidal influences. No significant drinking water sources exist within 1000 feet of the facility. The prevailing groundwater flow is generally to the north-northwest towards the Philippine Sea located 90 feet northnorthwest from the location of the UST excavation pit. Subsurface porosities in the vicinity of the site are mixed due to the heterogeneous nature of the detrital coralliferous limestone, beach deposits and artificial fill that comprises the subsurface at the site. Hydraulic conductivities in these mixed subsurface materials are estimated to be low to moderate within the vicinity of the site.
1 of 10
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Guam EPA, UST Closure Report GWA Piti Sewer Pump Station (CD-3), 350 G, Piti, Guam June 2011
1.6 Verification of Site Conceptual Model The presence of the 350-gallon UST was not verified during this investigation. Excavation activities at the probable location of the UST (based on metal detector survey) showed no indication of a UST system. Diesel Range Organics and BTEX compounds were not detected above laboratory reporting limits in the soil samples collected during this investigation. PAHs were detected at concentrations below regulatory thresholds in the soil samples. Diesel Range Organics were detected at a concentration of 817 Âľg/L in the groundwater sample collected from the excavation pit. Detections of several PAHs in the groundwater sample were also above regulatory thresholds. 1.7 Conclusions and Recommendations Based on these findings it is evident that minor fuel impacts exist in soil and groundwater at the site. While TPH was detected above the regulatory limit in groundwater, it was not detected above the reporting limit in soil. The presence of TPH in groundwater but not in the associated soil suggests that the source of the TPH contamination may be located outside of the area sampled. Based on this evidence, it is recommended that the Guam EPA consider sampling both soil and groundwater at one down-gradient location and one up-gradient location with respect to the UST excavation pit. An optimized remediation strategy should then be designed based on a determination of the location of the source of the fuel release.
2 of 10
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PITI UST SITE LOCATION
N
TITLE: MAP OF GUAM, INDICATING SITE LOCATION
apec allied pacific environmental consulting
PROJECT: PITI UST SITE INVESTIGATION
FIGURE: 1
N ONE MILE RADIUS
PIT UST SITE LOCATION
0
apec
TITLE: PROJECT STIE VACINITY MAP
allied pacific environmental consulting
PROJECT: PITI UST CLOSURE REPORT 2000 USGS
APPROXIMATE SCALE 0.25 0.5 MILES
FIGURE: 2
ANALYTICAL DATA
PITI 082510 001(GRAB, SOIL) DEPTH 5’ BGS ANALYTES: NOT DETECTED ABOVE REGULATORY LIMIT
N PITI BAY BUILDING
PITI 082510 002(GRAB, SOIL) DEPTH 7’ BGS ANALYTES: NOT DETECTED ABOVE REGULATORY LIMIT
VEGETATION
PITI 082510 003(GRAB, WATER) DEPTH 9’ BGS ANALYTES: TOTAL PETROLEUM HYDROCARBONS 817 ug/L (ppb) (REGULATORY LIMIT 50 ug/L) BENZO (A) ANTHRACENE 0.627 ug/L (ppb) (REGULATORY LIMIT 0.029 ug/L)
GENERATOR BUILDING EXCAVATED AREA MAIN SPS BUILDING
BENZO (A) PYRENE 0.510 ug/L (ppb) (REGULATORY LIMIT 0.0029 ug/L) BENZO (B) FLUORANTHENE 0.627 ug/L (ppb) (REGULATORY LIMIT 0.029 ug/L)
SAMPLE ID PITI082510 001
BENZO (K) FLUORANTHENE 0.392 ug/L (ppb) (REGULATORY LIMIT 0.29 ug/L)
DEPTH BGS 5’
PITI082510 002
7’
PITI082510 003
9’
INDENO (123-CD) PYRENE 0.392 ug/L (ppb) (REGULATORY LIMIT 0.029 ug/L) APPROXIMATE SCALE 0
apec
TITLE: SITE LAYOUT WITH ANALYTICAL DATA
allied pacific environmental consulting
PROJECT: PITI UST CLOSURE REPORT
12.5
25.0 FEET
FIGURE: 3
UNDERGROUND STORAGE TANK CLOSURE REPORT FOR 2,000-GALLON DIESEL FUEL TANK (GWA YPAO) AT GUAM WATERWORKS AUTHORITY YPAO SEWER PUMP STATION TUMON, GUAM
June 2011
Prepared for: Guam Environmental Protection Agency 17-3304 Mariner Avenue, Tiyan, Guam 96913 P.O. Box 22439 GMF, Barrigada, Guam 96921
apec
Prepared by:
allied pacific environmental consulting P.O. BOX 5091 AGANA, GUAM 96932 T 671.477.7310/12 | F 671.477.7311 | apecguam@guam.net
ll l
Guam EPA, UST Closure Report GWA Ypao Sewer Pump Station (Ypao Village), 2,000G, Tumon, Guam June 2011
1.0 EXECUTIVE SUMMARY 1.1
Introduction
A 2,000-gallon fiberglass reinforced plastic (FRP) underground storage tank (UST) was removed from the Guam Waterworks Authority (GWA), Ypao Sewer Pump Station (YSPS), Tumon, Guam in August 2010. Confirmation soil sampling was conducted on 31 August 2010. Olfactory, PID screening and confirmation soil sample analytical results indicate no significant impacts to the soil underlying the UST and associated fuel piping. 1.2
Sequence of UST Closure Activities
Notification for Underground Storage Tank Closure has been prepared for the Guam EPA and is included as an enclosure to thi s report. The concrete-slab demolition was conducted on 31 Au gust 2010. F orty gallons of liquid tank cont ents we re re moved and d isposed of following tan k cleaning on 1 Septembe r 2010. A Certified Industrial Hygienist (CIH) provided Gas-Free Certification on 1 September 2010. UST sidewall soil excavation was conducted on 31 August and 1 September 2010. The UST and associated piping was removed from the site an d pro perly disposed o r recycled o n 2 Septembe r 2 010. Soil a nd groundwater samples were collected for confirmation analysis on 31 August 2010. Following the direction and under the supervision of Guam EPA, APEC personnel backfilled the excavation area on 1 September 2010. 1.3
Site Investigation Activities
Site investigation activities consisted of visual, olfactory and PID fi eld screening and laboratory analytical soil testing for the followi ng analytes: 1) Total Extr actable Fuel Hydrocarbons (EF H) by EPA Method 8015B, 2) Polynuclear Aromatic Hydrocarbons including benzo(a)pyrene by EPA Method 8270C and 3) Benzene, Toluene, Ethylbenzene, Xylene by EPA Method 8260B. 1.4
Field Screening and Soil Sample Analytical Results
Visual, olfact ory, PID screenin g and confirmation soil analytical result s indi cate level s of petroleum contamination belo w p roject cl ean-up goals at the site of the subject UST, a ssociated pi ping, and soil overburden. 1.5
Site Conceptual Model
The site co nceptual model is base d on field obse rvations and laboratory analytical testing p erformed on environmental media collected at the site and the geological and hydrological conditions at the site. Elevations within the pe rimeter fence of the site range from approximately 17ft â&#x20AC;&#x201C; 22ft above MSL. The slope within the perimeter fence of the site is 0.05 ft per foot (5% slope) and is graded downward towards the no rtheast. The elevation at th e site of the UST excavatio n pit is app roximately 18ft above MSL. Approximately fifty-perce nt (50% ) of t he site i s covered by im pervious surfaces i ncluding buil dings, concrete footings, and pavement. The remaining undeveloped areas of the site are vegetated with grass. The undeveloped portions of the property absorb a portion of the stormwater run-off from the site. Storm water drains from the nearby rooftop of the generator building associated with the subject UST through a vertical conduit onto the grassy su rface near the location of the UST. The UST and asso ciated fuel lines were intact without visible signs of corrosion or release of fuel. Depth to groundwater at the location of the UST excavation is approximately 18 ft below ground surface. Groundwater at the site i s brackish water as freshwater and seawater are significantly mixed due to tidal influences. No significant drinking water sources exist within 1000 feet of th e facility. The prevailing groundwater flow is generally to the north-northeast towards the Philippine Sea. Subsurface porosities in the vicinity o f the site are mixed d ue to the het erogeneous n ature of th e a rtificial fill th at has be en 1 of 11
apec
P.O. BOX 5091, HAGATNA, GUAM 96932 | TEL. 671.477.7310/12/14 | FAX 671.477.7311 | apecguam@ guam.net
Guam EPA, UST Closure Report GWA Ypao Sewer Pump Station (Ypao Village), 2,000G, Tumon, Guam June 2011
deposited i n the area. Hydraulic conductivities in the a rtificial fil l ma terials are estim ated t o be l ow to moderate within the vicinity of the site. 1.6
Verification of Site Conceptual Model
Visual, olfa ctory an d PID field screeni ng of excavat ed soil revea led no impa cts of fuel product in the vicinity of the UST. The laboratory analytical results for soil obtained from 4ft below the fuel line indicated levels of Total Extractabl e Fuel Hydro carbons bel ow the 50 mg /kg (pp m) screeni ng thre shold. Minor detections of PAHâ&#x20AC;&#x2122;s were also discovered below their respective screening threshold. All other analytes tested in soils obtained at the site were found to be below regulatory limits. 1.7
Conclusions and Recommendations
Based on these findings it is evident that minor impacts exist in the area of the location of former UST and associated piping and that no significant impacts to groundwater exist at the site. Future re lease of fu el form thi s lo cation h as be en p revented by the re moval of the pi ping it s a ssociated UST. Based on a review of th e evidence presented within this UST closure report it is recommended that no further action be considered at the site.
2 of 11
apec
P.O. BOX 5091, HAGATNA, GUAM 96932 | TEL. 671.477.7310/12/14 | FAX 671.477.7311 | apecguam@ guam.net
YPAO UST SITE LOCATION
apec allied pacific environmental consulting
TITLE: MAP OF GUAM, INDICATING SITE LOCATION PROJECT: YPAO UST SITE INVESTIGATION
FIGURE: 1
YPAO UST SITE LOCATION
ONE MILE RADIUS
0
APPROXIMATE SCALE 0.25
0.5
MILES
apec
TITLE: PROJECT SITE VICINITY MAP
allied pacific environmental consulting
PROJECT: YPAO UST CLOSURE REPORT 2000 USGS
FIGURE: 2
ANALYTICAL RESULTS IPAO083110001 (GRAB) DEPTH 4’ BGS TIME 09:05 ANALYTES: EFH (4.14 mg/kg) IPAO083110003 (GRAB) DEPTH 10’ BGS TIME 09:05 ANALYTES: EFH (13.8 mg/kg)
FENCELINE PARKING LOT DENSE VEGETATION
IPAO083110002 (COMPOSOITE) DEPTH 1’ BGS TIME 09:05 ANALYTES: EFH (10.5 mg/kg)
PUMP STATION
LEGEND VENT LINE
DENSE VEGETATION
FUEL PIPING
ROAD
EXCAVATED AREA UST LOCATION SOIL STOCKPILE
GENERATOR BUILDING
DENSE VEGETATION
IPAO083110003 IPAO083110001 IPAO083110002 0
APPROXIMATE SCALE 12.5 25 FEET
TRANSFORMER
apec
TITLE: SITE PLAN INDICATING SAMPLE LOCATIONS AND ANALYTICAL RESULTS
allied pacific environmental consulting
PROJECT: YPAO UST CLOSURE REPORT
FIGURE: 3