DRAFT REMEDIAL ACTION PLAN FORMER SHELL SERVICE STATION 406 NORTH GAFFEY STREET (AT O’FARRELL) SAN PEDRO, CALIFORNIA March 17, 2011 SUBMITTED TO: CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD – LOS ANGELES REGION 320 West 4 th Street, Suite 200 Los Angeles, California 90013-2342 Attention: Dr. Yue Rong PREPARED FOR: SHELL OIL PRODUCTS US 20945 South Wilmington Avenue Carson, California PREPARED BY: WAYNE PERRY, INC. 8281 Commonwealth Avenue Buena Park, California 90621 (714) 826-0352 WPI PROJECT NO.: 11.372 CRWQCB-LA CASE NO.: 907310543 SAP CODE: 136042 EAOP SITE DRAFT
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REMEDIAL ACTION PLAN FORMER SHELL SERVICE STATION 406 NORTH GAFFEY STREET (AT O’FARRELL) SAN PEDRO, CALIFORNIA March 17, 2011 SUBMITTED TO: CALIFORNIA REGIONAL WATER QUALITY CONTROL BOARD – LOS ANGELES REGION 320 West 4th Street, Suite 200 Los Angeles, California 90013-2342 Attention: Dr. Yue Rong PREPARED FOR: SHELL OIL PRODUCTS US 20945 South Wilmington Avenue Carson, California PREPARED BY: WAYNE PERRY, INC. 8281 Commonwealth Avenue Buena Park, California 90621 (714) 826-0352 WPI PROJECT NO.: 11.372 CRWQCB-LA CASE NO.: 907310543 SAP CODE: 136042 EAOP SITE
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REMEDIAL ACTION PLAN, SHELL-BRANDED SERVICE STATION
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WARRANTY STATEMENT: This report has been prepared by Wayne Perry, Inc. (WPI) for the exclusive use of Equilon Enterprises LLC dba Shell Oil Products US, as it pertains to the former Shell Service Station located at 406 North Gaffey Street (at O’Farrell) in San Pedro, California. Our professional services have been performed using that degree of care and skill ordinarily exercised under similar circumstances by other geologists, hydrogeologists, and engineers practicing in this field. No other warranty, express or implied, is made as to the professional advice in this report. If you have questions or require additional information regarding this report, please contact Ms. Deborah Pryor of Shell at (323) 291-9595 or Ginny Murphy of WPI at (714) 826-0352. PREPARED BY: Cristi A. Farrell David M. Henry Project Manager California Registered Geologist 4085 March 17, 2011 WPI PROJECT NUMBER: 11.372
cc: Ms. Deborah Pryor, Shell Mr. Hamid Pournamdari, Property Owner
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TABLE OF CONTENTS 1.0 INTRODUCTION ........................................................................................................................................................ 1
2.0 SITE DESCRIPTION .................................................................................................................................................. 1
2.1 SITE DESCRIPTION ...................................................................................................................................................... 1 2.2 SITE HISTORY ............................................................................................................................................................. 1 2.3 SITE HYDROGEOLOGY ................................................................................................................................................ 3 2.4 POTENTIAL SENSITIVE RECEPTORS ............................................................................................................................. 4
3.0 DISTRIBUTION OF HYDROCARBONS ................................................................................................................. 4
6.0 PROPOSED SCOPE OF WORK ................................................................................................................................ 6
6.1 EXTRACTION WELL INSTALLATION ............................................................................................................................ 6 6.1.1 Pre-Field Procedures ......................................................................................................................................... 6 6.1.2 Well Installation ................................................................................................................................................. 7 6.1.3 Reporting ............................................................................................................................................................ 9
6.2 VERIFICATION MONITORING PROGRAM ...................................................................................................................... 9 6.2.1 Compliance Monitoring ..................................................................................................................................... 9 6.2.2 System Performance Monitoring ........................................................................................................................ 9 6.2.3 Groundwater Monitoring Program .................................................................................................................. 10
TABLES 1, Boring/Well Data 2, Soil Analytical Data 3, Groundwater Analytical Data 4, Dual-Phase Extraction System Data DRAFT
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FIGURES 1, Site Location Map 2, Plot Plan 3, Groundwater Elevation Contour Map 4, Benzene Isoconcentration in Soil at 20 Feet 5, Benzene Isoconcentration in Soil at 30 Feet 6, Benzene Isoconcentration in Soil at 40 Feet 7, MTBE Isoconcentration in Soil at 20 Feet 8, MTBE Isoconcentration in Soil at 30 Feet 9, MTBE Isoconcentration in Soil at 40 Feet 10, TPPH Isoconcentration in Groundwater Map 11, Benzene Isoconcentration in Groundwater Map 12, MTBE Isoconcentration in Groundwater Map 13, TBA Isoconcentration in Groundwater Map
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1.0 INTRODUCTION
Data from previous phases of site assessment indicate that soil and groundwater beneath the former Shell Service Station located at 406 North Gaffey Street (at O’Farrell Street) in San Pedro, California (site), have been impacted by petroleum hydrocarbons and oxygenated compounds. Wayne Perry, Inc. (WPI) on behalf of Equilon Enterprises LLC dba Shell Oil Products US (Shell) is submitting a remedial action plan, which provides a comprehensive review of the site and recommendations for a remedial alternative to reduce the extent of benzene- and MTBE-impacted soil and groundwater beneath the site. In correspondence dated February 15, 2005, the California Regional Water Quality Control Board-Los Angeles (CRWQCB-LA) identified this site as a Class D clean up priority and placed it in the self directed Expedited Agency Oversight Program (EAOP). Accordingly, this report is being submitted per EAOP guidelines as outlined in the CRWQCB-LA letter and guidance document, dated February 15, 2005, and January 18, 2006.
2.0 SITE DESCRIPTION
2.1 SITE DESCRIPTION The site is on the northeast corner of the intersection of North Gaffey and O’Farrell Streets in San Pedro (Figure 1). Three 12,000-gallon underground storage tanks (USTs), one 550-gallon waste oil UST, four fuel dispensers, and associated underground product piping were removed from the site in June 2000 (Figure 2). The station building with three service bays was later demolished by the property owner. The hoists and clarifier were removed from the site in July 2010. The site is currently vacant. Surrounding land use is a mixture of residential and commercial. A single-family residence, a pedestrian overpass for North Gaffey Street, and the 110 Freeway are located north of the site across the alley. Single-family residences are located east of the site across Oliver Street. A two-story commercial building with subterranean parking is located south of the site across O’Farrell Street. The City of San Pedro Welcome Park is located west of the site across North Gaffey Street.
2.2 SITE HISTORY Date Activity/Method No. of Wells,
Borings or Samples
Report Date
Consultant Comments
4/94 Product Line Leak __ __ __ The Los Angeles City Fire Department (LACFD) records for April 26, 1994, indicate that a gasoline product line failed a hydrostatic test and had an estimated leak rate of 0.03 gallon/hour.
6/98 UST Upgrade Sampling
__ __ WPI Total petroleum hydrocarbons as gasoline (TPHg), benzene, and methyl tertiary butyl ether (MTBE) were not detected in any of the soil samples.
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Date Activity/Method No. of Wells, Borings or Samples
Report Date
Consultant Comments
12/99 Phase I Environmental
Assessment
__ 1/31/00 Artemis
1/00 Phase II Site Assessment
9 soil borings (WGR-1 through
WGR-9)
2/12/00 WGR TPH-g, benzene, and/or MTBE were detected in soil samples to a maximum depth of approximately 40 feet.
6/00 UST Removal __ 10/2/00 WGR MTBE was detected in soil samples collected beneath the USTs and dispensers.
5/05 Agency Correspondence
__ 5/25/05 __ The LACFD transferred the environmental case to the CRWQCB-LA.
7/05 Agency Correspondence
__ 7/27/05 __ The CRWQCB-LA requested additional information.
8/05 Response to Agency __ 8/29/05 WGR WGR provided the CRWQCB-LA with additional information.
2/06 Site Assessment Work Plan
__ 2/28/06 WGR WGR proposed drilling/sampling four soil borings and the installation of three groundwater monitoring wells.
8/8/06 WGR TPHg, benzene, MTBE, and tertiary butyl alcohol (TBA) were detected in soil and/or groundwater samples. Off-site soil borings were unable to be completed due to delays in permitting.
7/06 –
7/09
Quarterly Groundwater Monitoring
__ __ Various
11/06 Agency Correspondence
__ 11/9/06 __ The CRWQCB-LA placed the site in the EAOP Class D program.
11/06 to
8/08
Site Redevelopment __ __ __
8/08 Work Plan for Additional Site
Assessment
__ 8/27/08 WPI WPI proposed installation of four groundwater monitoring wells to define the lateral extent of impacted groundwater.
9/08 Additional Site Assessment
3 GW wells (MW-5 to MW-7)
1/19/09 WPI The lateral extents of hydrocarbon- and oxygenate-impacted soil and groundwater remain undefined.
12/08 Work Plan for Additional Assessment
__ 12/17/08 WPI WPI proposed drilling/sampling one boring and performing a soil vapor survey and aquifer test.
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Date Activity/Method No. of Wells, Borings or Samples
Report Date
Consultant Comments
1/09 Additional Site Assessment and
Interim Remedial Action Plan
1 soil boring (B-1); 12 soil vapor probes
(SV-1 to SV-12)
6/22/09 WPI BTEX and MTBE were detected in soil vapor samples; however residual BTEX and MTBE concentrations in soil vapor beneath the site do not pose a health risk. WPI proposed five GW wells to further define the lateral extent of impacted groundwater. WPI also proposed installation of six observation wells to be used in conjunction with a DPE pilot test.
6/09 State Water Resources Control
Board Resolution No. 2009-0042
__ 6/15/09 __ Resolution allowed for the reduction/alteration of the existing sampling schedule.WPI recommended wells MW-1 through MW-6 be sampled semi-annually in the first and third quarters, and street well MW-7 be sampled annually in the first quarter.
7/09 –
Current
Semi-Annual Groundwater
Monitoring and Sampling
__ __ WPI The frequency of groundwater monitoring and sampling was reduced to semi-annual.
10/09 Additional Site Assessment
5 GW wells (MW-8 through
MW-12)
3/4/10 WPI Data indicate the extent of HCs and oxygenates in the groundwater remain undefined. Access to the west and north of the site is restricted by Gaffey and the 110 Freeway. Additional wells were proposed to the northeast and east of the site to delineate the extent in those directions.
10/09 Dual-Phase Extraction Pilot Test
6 observation wells
(OB-1 through OB-6)
3/9/10 WPI Data indicate soil vapor extraction appears to be feasible. ROI was calculated at approximately 20 feet. Groundwater extraction did not appear to be feasible due to low extraction rates. An air sparge well installation and pilot test were proposed.
4/10 Air Sparge Pilot Test 1 air sparge well (AS-1)
9/22/10 WPI Based on fact that no flow was achievable under the fracture pressure, air sparging does not appear to be a feasible remedial alternative for groundwater.
Boring/well data is in Table 1. Soil analytical data is in Table 2. Groundwater data is in Table 3.
2.3 SITE HYDROGEOLOGY Based previous phases of assessment, the site is underlain by gravelly fine- to coarse-grained sand, sandy silt, silt with clay, and silt with fine-grained sand to a depth of approximately 15 feet, and siltstone/claystone from approximately 15 to 55 feet (WPI, 2009).
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Since groundwater monitoring was initiated in 2006, the depth to groundwater at the site has ranged from approximately 34 to 38 feet. Groundwater flow is toward the north and east at a gradient between 0.02 and 0.03 foot/foot (Figure 3).
2.4 POTENTIAL SENSITIVE RECEPTORS Based on information provided by the Los Angeles County Department of Public Works (LACDPW) Ground Water Wells website, there are no active wells within one mile of the site (LACDPW, 2009). There are two schools and two child care centers located within 0.5-mile of the site. A summary of sensitive receptors is in Table 2.4.
Table 2.4, Sensitive Receptor Information
Facility Distance from Site Direction from Site Barton Hill Elementary 0.2-mile East
Toberman Child Care Center 0.2-mile Southeast Comprehensive Child Development 0.3-mile South
Bandini Street Elementary 0.4-mile West
3.0 DISTRIBUTION OF HYDROCARBONS
3.1 SOIL Analytical data indicate that soil from depths of approximately 20 to 50 feet in the vicinity of borings WGR-3, WGR-10, MW-1, MW-2, MW-3, MW-5, MW-6, and MW-12 have been impacted by benzene and/or MTBE at concentrations in excess of 1,000 μg/kg. Based on the depth to water and lateral extent of impacts, petroleum hydrocarbons detected in soil are located primarily in the saturated zone and are present as dissolved-phase. The lateral extent of benzene-impacted soil at depths of 20 and 30 feet are undefined to the west of MW-1 (Figures 4 and 5); and below the water table at 40 feet, the extent is undefined to the west of MW-1 and MW-12 (Figure 6). The lateral extent of MTBE-impacted soil at a depth of 20 feet is undefined to the west of MW-1 and MW-6 (Figure 7). The lateral extent of MTBE-impacted soil at a depth of 30 feet is undefined west of MW-6 and southwest of MW-3 (Figure 8). Below the water table at a depth of 40 feet, the extent of MTBE impacts decreases in magnitude and remain undefined west of MW-5 (Figure 9). Based on the data, the lateral extent of petroleum hydrocarbon-impacted soil beneath the site have not been defined to the west of the site and wells MW-11 and MW-12. Further delineation of petroleum hydrocarbon-impacted soil west of the site in North Gaffey Street is not possible. Access to North Gaffey Street adjacent to the site is handled by Caltrans. Previous requests to Caltrans for access to install monitoring wells in North Gaffey Street have been denied; therefore, a request has been made to the City of San Pedro to allow for access to install monitoring wells at the City of San Pedro Welcome Park. Further delineation to the north of the site and wells MW-11 and MW-12 is not possible due to the presence of the 110 Freeway.
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3.2 GROUNDWATER Based on the data, TPPH impacts to groundwater are laterally widespread and the extent is undefined (Figure 10). Benzene-impacted groundwater is undefined primarily to the west of MW-1, MW-5, and MW-12 and southwest of MW-6 and MW-7 (Figure 11). MTBE impacts to groundwater have been adequately defined (Figure 12). TBA impacts to groundwater are undefined west of MW-12 (Figure 13).
4.0 EVALUATION OF REMEDIAL OPTIONS
4.1 EXCAVATION Excavation of hydrocarbon-impacted soil could effectively remove the source areas and reduce additional diffusion of hydrocarbons and oxygenates into groundwater beneath the site. Based on the data, the bulk of soil impacts at the site are at depths from approximately 20 to 50 feet. Standard excavating methods would require shoring and dewatering of the excavation in order to remove all the impacted soil beneath the site. However, an alternative to using an excavator would be to drill out the impacted soil with a construction auger. An array of borings could be drilled to a depth of approximately 50 feet and backfilled with two-sack cement slurry to within approximately five feet from the surface. If excavation is limited to areas where benzene and/or MTBE impacts exceed 1,000 μg/kg, the area of excavation would have to include the locations of borings WGR-3, WGR-10, MW-1, MW-2, MW-3, MW-5, and MW-6 (approximately 8,000 square feet). Although technically feasible, excavation would not remediate the laterally extensive off-site groundwater impacts or provide hydraulic containment of impacted groundwater. As such, excavation is not considered an acceptable remedial option at this site.
4.2 DUAL-PHASE EXTRACTION In October 2009, a 10-hour DPE test was performed by Frontier Environmental Services, Inc. and overseen by WPI. Well MW-2 was used for extraction and wells OB-1 through OB-6, MW-1, and MW-3 were used for observation. DPE system data are summarized in Table 4. Based on the data, the effective radius of vacuum influence at the site is approximately 20 feet; however, the results of the pilot test suggest that preferential pathways influenced the flow rate in the direction of wells OB-2 through OB-5. Laboratory data indicated that hydrocarbon mass removal rates varied from 2.5 to 3.5 pounds per hour with approximately 32 pounds of vapor-phase hydrocarbons recovered over a 10-hour period (WPI, 2010a). The average groundwater recovery rate during the pilot test was approximately 0.1 gpm. The average drawdown observed in wells OB-1 through OB-6, located between 9 and 15 feet from extraction well MW-2, was less than one foot. Based on the data, soil vapor extraction appears to be effective in reducing residual hydrocarbons and fuel oxygenates in soil; however, groundwater extraction appears to be limited by site lithology.
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4.3 AIR SPARGING In May 2010, an air sparge pilot test was performed by WPI. Well AS-1 was used for injection and wells MW-1 through MW-6 and OB-1 through OB-6 were used for observation. Flow into AS-1 was attained at 10 psi over the estimated fracture pressure. Distribution of impact in nearby observation wells and monitoring wells show a directional bias. The dissolved oxygen data showed a strong north-northeast/south-southwest trend in wells up to 10 feet away from the injection point, but wells six feet to the north and nine feet to the east-northeast showed no appreciable change (WPI, 2010b). Based on the data, air sparging does not appear to be a feasible remedial alternative.
5.0 DISCUSSION Although soil vapor extraction appears to be a more feasible method than dual-phase extraction, petroleum hydrocarbon impacts in soil extend approximately 10 feet beneath the water table. Dual-phase extraction will be implemented to draw down groundwater to expose the soil column beneath the water table. However, dual-phase extraction is not expected to remediate all the impacts in groundwater or soil impacts due to low permeability and preferential pathways in the formation. Based on the radius of vacuum influence obtained during the October 2009 DPE test and the presence of preferential pathways influencing the test wells, a more conservative radius of vacuum influence will be used to develop the well array. A high vacuum DPE system will be installed at the site for hydrocarbon mass removal from the source area. The proposed system will include a network of aboveground piping and extraction wells, and soil vapor extraction and groundwater treatment systems. Soil vapor and groundwater will be extracted using a stinger tube connected to a vacuum pump and positioned in the well with the end of the tube slightly below groundwater surface. The stinger tube will be gradually lowered to the desired depth below the static water level to create a cone of depression in the vicinity of the well. Groundwater will be separated from the vapor aboveground and the vapors will be oxidized by the treatment unit. Treated groundwater from the system will be piped aboveground into the sewer for discharge. Six vadose zone vapor recovery wells and 13 dual-phase extraction wells will be installed prior to constructing the remediation system and compound.
6.0 PROPOSED SCOPE OF WORK
6.1 EXTRACTION WELL INSTALLATION 6.1.1 Pre-Field Procedures Pre-field activities will include the following:
• Updating the existing WPI SSHP, as necessary; • Scheduling subcontractors; • Notifying Underground Service Alert at least one week prior to commencement of work to
perform an underground utility clearance for the planned drilling location; and,
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• Obtaining well installation permits. Prior to any excavation, a utility line survey will be performed to locate all underground utility lines beneath the proposed locations. All boring locations will be air-knifed to a depth up to 10 feet and to a width three inches larger than that of the lead auger.
6.1.2 Well Installation One soil boring will be drilled/sampled near MW-6 to determine the vertical extent of impacts prior to determining an appropriate well screen for vapor- and dual-phase extraction wells. Shallow and deep well screens will be selected based on a review of the analytical data. Six soil vapor and 13 dual-phase extraction wells will be installed. Proposed boring and well locations are shown on Figure 2. Details of the drilling and sampling schedule are in Table 6.1.2a. Details of the well construction are in Tables 6.1.2b and 6.1.2c.
Table 6.1.2a, Drilling and Sampling Information
Number
of Borings
Depth of Boring (feet)
Drilling Method
Sample Interval
(feet)
Sample Method Sample Analysis
4 35 Hollow stem auger
10-35 - -
2 35 Hollow stem auger
10-35 - -
12 46 Hollow stem auger
10-45 Modified California split
spoon; EPA Method 5035
Selected locations will be analyzed for TPPH, BTEX, and fuel oxygenates
using EPA Method 8260B (standard turnaround)
1 51 Hollow stem auger
10-50 - -
1 70 Hollow stem auger
10-70 Modified California split
spoon; EPA Method 5035
TPPH, BTEX, and fuel oxygenates using EPA Method 8260B (5-day
turnaround)
Table 6.1.2b, Vapor Extraction Well Construction Data
REMEDIAL ACTION PLAN, FORMER SHELL SERVICE STATION
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Table 6.1.2c, Dual-Phase Extraction Well Construction Data
Number of Wells
Type of Well
Depth of Well (feet)
Casing Material Screen Interval
(feet)
Filter Pack
Interval (feet)
Well Seal Intervals (feet)
Bentonite Chips
Neat Cement
12 Dual-Phase Extraction
46 Blank: 4-inch diameter, schedule 40 PVC Slotted Casing: 4-inch diameter, schedule 40 PVC with factory milled 0.02-inch slots with a one-foot sump at the bottom
35-45 34-46 30-34 0.5-30
1 Dual-Phase Extraction
51 Blank: 4-inch diameter, schedule 40 PVC Slotted Casing: 4-inch diameter, schedule 40 PVC with factory milled 0.02-inch slots with a one-foot sump at the bottom
40-50 39-51 35-39 0.5-35
Soil generated from the borings will be placed in a roll-off bin and sealed upon completion of work activities. The soil cuttings will remain in the bin on-site until they can be properly disposed. At least 72 hours after completion, the groundwater extraction wells will be developed by surging and bailing. A surge block will be use d to draw fine-grained material into the well where it will be removed. After a period of surging, water and suspended fines will be removed using a PVC bailer. This process will be repeated until the removed water contains less than 10 NTUs of suspended solids or a baseline level of turbidity is established. Groundwater depths before and after development, well depth, well development times and dates, volumes of water removed, and turbidity levels will be recorded on a well development log. To prevent cross-contamination, the surge block and bailer will be washed with non-phosphate soap and double rinsed in de-ionized water prior to each measurement. To avoid cross-contamination, all reusable equipment will be broken down prior to and after each use and cleaned, using an approved non-phosphate detergent, double-rinsed in distilled water, and allowed to air dry. All work will be performed under a site-specific WPI SSHP and the supervision of a California Professional Geologist.
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6.1.3 Reporting WPI will submit a report documenting results of the well installation to the CRWQCB-LA within 75 days of completion of field activities. The report will include:
• Objectives and background; • Methods and procedures; • Discussion of results; • Chemical and field measurement data summarized in tables; • Copies of laboratory reports and chain-of-custody documents; and • Conclusions and recommendations based on results.
6.2 VERIFICATION MONITORING PROGRAM The verification monitoring program will be composed of three parts: (1) compliance monitoring for water discharge permit and SCAQMD Permit to Operate; (2) treatment system performance monitoring; and (3) the ongoing groundwater monitoring program.
6.2.1 Compliance Monitoring Monitoring required by the POTW discharge permit will normally consist of the following:
• Weekly monitoring of treatment system flow rate;
• Monthly sampling of treatment system effluent and laboratory analysis of samples for
TPH-G, BTEX, and MTBE; and,
• Annual sampling of treatment system effluent and laboratory analysis of samples for
volatile organics, semi-volatile organics, and aquatic toxicity.
Monitoring required by the SCAQMD Permit to Operate is expected to consist of the following:
• Weekly monitoring of thermal or catalytic oxidizer temperature and system flow rate;
• Weekly sampling of oxidizer influent and effluent and field OVA analysis for VOCs;
and,
• Monthly sampling of oxidizer effluent and laboratory analysis for benzene.
6.2.2 System Performance Monitoring The objective of performance monitoring is to maximize the removal rate of hydrocarbons in the dissolved and vapor phase while ensuring that pumps and surface treatment equipment are operating within normal design parameters. Performance monitoring of the DPE system will include the following field measurements and sampling: • System vacuum (weekly);
• System flow rate (weekly);
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• Volume of groundwater extracted and treated (weekly);
• System influent hydrocarbon vapor concentration (field FID) (weekly);
• Vacuum at extraction wells and observation wells (weekly);
• Individual DPE well hydrocarbon vapor concentrations (field FID) (weekly);
• Review of stinger depths (weekly);
• Review selection of active/inactive DPE wells (weekly);
• Sampling and laboratory analysis of combined system vapor (monthly);
• Sampling and laboratory analysis of system influent groundwater (monthly);
• Sampling and laboratory analysis of groundwater from individual DPE wells (quarterly);
and,
• Sampling and laboratory analysis of individual well vapor (quarterly).
6.2.3 Groundwater Monitoring Program The current quarterly groundwater gauging and monitoring program will continue with the exception that the wells connected to the DPE system will not be sampled. Groundwater samples will normally be collected from extraction wells as part of the system performance monitoring program. The groundwater samples will be analyzed for TPPH, BTEX, MTBE, di-isopropyl ether, ethyl tertiary butyl ether, tertiary amyl methyl ether, and tertiary butyl alcohol using EPA Method 8260B.
6.3 SCHEDULING The proposed activities will be initiated upon receipt of appropriate permits. A well installation report summarizing the procedures and results of the assessment and a system installation report will be submitted to the CRWQCB-LA within 75 days following completion of all field activities.
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7.0 REFERENCES
Los Angeles County Department of Public Works (LACDPW) Ground Water Wells Website [http://dpw2.co.la.ca.us/website/wells/viewer.asp], 2009, reviewed on January 27, 2009.
Wayne Perry, Inc. (WPI), 2009, Additional Site Assessment and Interim Remedial Action Plan,
Former Shell Service Station, 460 North Gaffey Street (at O’Farrell), San Pedro, California; Unpublished report for Shell Oil Products US, dated June 22, 2009.
WPI, 2010a, Dual-Phase Extraction Pilot Test Report, Former Shell Service Station, 406 North
Gaffey Street (at O’Farrell), San Pedro, California; Unpublished report for Shell Oil Products US, dated March 9, 2010.
WPI, 2010b, Air Sparge Pilot Test Report, Former Shell Service Station, 406 North Gaffey Street (at
O’Farrell), San Pedro, California; Unpublished report for Shell Oil Products US, dated September 22, 2010.
