SUBSURFACE INVESTIGATION REPORT. Industrial Building rd Street San Francisco, California

Transcription

1 SUBSURFACE INVESTIGATION REPORT Industrial Building rd Street San Francisco, California PREPARED BY: James S. Koniuto, Project Manager REVIEWED BY: Michael L. Siembieda Senior Project Manager RG #4007

2 TABLE OF CONTENTS I. EXECUTIVE SUMMARY...1 II. INTRODUCTION...3 A. Site Description...4 B. Site History...4 C. Geology and Hydrology...4 D. Previous Investigations...5 E. Purpose and Scope of Work...5 III. PROJECT ACTIVITIES...6 A. Underground Utility Clearing...6 B. Permit...6 C. Soil Sampling...6 D. Groundwater Sampling...7 E. Laboratory Analyses...7 IV. INVESTIGATION FINDINGS...8 A. Subsurface Conditions...8 B. Analytical Results...8 C. Regulatory Guidelines and Discussion of Findings...9 V. CONCLUSIONS AND RECOMMENDATIONS...12 VI. REPORT LIMITATIONS...12 VII. REFERENCES...13

3 TABLE OF CONTENTS (continued) TABLES Table 1 - Summary of Analytical Results - Soil Samples Table 2 - Summary of Analytical Results - Groundwater Samples FIGURES Figure 1 - Site Location Map Figure 2 - Site Plan with Soil Boring Locations LABORATORY REPORT APPENDICES Appendix A - Boring Permit, Boring Logs and Log Legend Appendix B - General Conditions and Request for Reliance

4 I. EXECUTIVE SUMMARY SUBSURFACE INVESTIGATION 5800 Third Street San Franicsco, California AllWest conducted a subsurface investigation at the subject property located at rd Street, San Francisco, California on April 10, The purpose of the investigation was to assess soil and groundwater concerns associated with the historical land use of the subject property. This executive summary is provided solely for the purpose of overview. Any party who relies on this report must read the full report. The executive summary omits a number of details, any one of which could be crucial to the proper understanding and risk assessment of the subject manner. The property is located on a level, rectangular-shaped parcel of land currently developed with a multi-level reinforced concrete building. Also present on the property is a waste water treatment building, guard house, office trailer, sugar silo, bus maintenance sheds, canopied truck scale, railroad tracks, one 10,000 gallon heating oil underground storage tank (UST), and above ground storage tanks. Figures 1 and 2 denote the site vicinity and site plan. The investigation program as outlined in AllWest's April 2, 2003 proposal included the advancement of fourteen (14) soil borings by a direct push drilling method. Three borings could not be advanced past surface material material due to the presence of metal re-bar, concrete, rock and other debris. One boring was not advanced do to subsurface utility concerns..the borings were sited throughout the property at areas of potential environmental concern and to obtain representative samples from all areas of the property. All borings were located outside of the buildings. No access to the interior of the building for drilling was granted by the current owner. A total of thirty four (34) soil, and four (4) groundwater) water samples were collected for chemical analyses. Selected soil and groundwater samples were analyzed for Total Petroleum Hydrocarbons (TPH) as diesel and motor oil (TPH-d and TPH-mo), volatile organic compounds (VOCs). Selected soil samples were analyzed for the metals: cadmium, chromium, lead, nickel, and zinc and pesticides. Two soil samples collected from the railroad track area were analyzed for creosote (phenols). Table 1 and 2 summarize soil and groundwater analytical results. A review of soil analytical data indicated that TPH-d was detected only at low concentrations in 7 of 9 samples tested. The highest concentration, 30 milligrams per kilogram (mg/kg), 1

5 equivalent to 30 parts per million (ppm), was detected in a soil sample collected from a boring adjacent to the 10,000 gallon diesel fuel tank. Concentration detected at this location are well below the 500 mg/kg risk based screening level (RBSL), for TPH (middle distillates) in surface soil in a residential setting where groundwater is not considered a potential drinking water source (RWQCB December 2001). TPH-mo was detected in 3 of 9 samples at a maximum concentration 400 mg/kg. This concentration is below the RBSL for residual fuels of 500 mg/kg. Ten (10) soil samples were analyzed for volatile organic compounds(vocs). No VOCs were detected in any of the samples. Seven soil samples were analyzed for organochlorine pesticides. No pesticides were detected. Ten soil samples were analyzed for metals. Concentrations of metals were either below RBSLs or at concentrations considered background or naturally occurring given the sites geologic setting. Additionally, the levels of these metals were also below the EPA s Region IX, Preliminary Remediation Goals (PRGs) Phenols (creosote) were detected in the two samples analyzed for the constituent at a concentrations of 0.23 mg/kg and 0.39 mg/kg, respectively. The concentrations are well below the RBSL of 39 mg/kg and the EPA PRG of 37,000 mg/kg. Four groundwater samples were analyzed for TPH-d, TPH-mo, and for VOCs. TPH-d was detected in the sample collected from boring B-7 at a concentration of 130 micrograms per liter (ug/l), which is equivalent to part per billion (ppb). TPH-mo also was detected in the sample collected from B-7 at a concentration of 1,900 ug/l. TPH was not detected in the other samples analyzed. Only two VOCs were detected, 1.1 ug/l of 1,2 Dichloroethane (1,2-DCA) in the sample collected from boring B-7 and 5.2 ug/l of Methyl tert butyl Ester (MTBE) in the sample collected from boring B-10. Since the local groundwater is not considered a potential drinking water source and no impact to aquatic life is anticipated, only the impact of the chemicals detected to residential indoor air quality was assessed. The RWQCB considers TPH (middle distillates) and TPH (residual fuels) (i.e. TPH-d and TPH-mo,) as non volatile, so impact to indoor air is not a consideration. The concentrations of the volatile constituents 1,2-DCA and MTBE are well below their RBSLs of 500 ug/l and 50,000 ug/l, respectively, for protection of indoor air quality in a residential setting. No specific source has been identified for the low concentrations of TPH-d and TPH-mo detected at the property. The positive detections could be a result of surface spills, storm water runoff infiltrations or other minor releases. The highest concentration of TPH in soil was detected in a soil sample collected from boring B-4, located adjacent to the 10,000 gallon UST. The groundwater sample collected from this location did not detect any TPH, therefore no large release is indicated. The highest concentration of TPH in groundwater was detected in the sample collected from boring B-7, located in front of the main building. No specific source was 2

6 identified though trucks and vehicles in various states of disrepair are stored at this location. Leaks from vehicle fuel tanks, crankcases and infiltration through cracked asphalt may be the source of the TPH detected in this area. No specific source was identified for the very low levels of the solvent 1,2-DCA and the gasoline additive MTBE. 1,2-DCA is a common industrial solvent used for a variety of industrial purposes. MTBE is a gasoline additive that is highly mobile in the environment. The low levels of phenols detected may be related to residual levels of creosote left from former railroad activities or possibly related to asphalt material incorporated in the shallow soil. Based on our understanding of the history and use of the property, results of analytical testing of soil and groundwater samples, and a review of regulatory standards no significant soil or groundwater environmental hazards were identified that would impair site development for residential use. Various chemicals including petroleum hydrocarbons and other organic constituents were detected below regulatory risk based screening levels for residential use. Metals were detected at background levels. No pesticide were detected. Further subsurface soil or groundwater investigations are not recommended at the present time. Because of the inherent limitations of our investigation, the possibility exists that undiscovered areas exist at the property that contain hazardous materials requiring further evaluation. These areas may not become evident until the building, UST, ASTs, asphalt and concrete are removed, and grading commences. Therefore we recommend the demolition and grading contractor maintain contingency plans for the possibility that potentially hazardous materials are encountered. If suspected contamination is identified or hazardous materials are encountered, AllWest should be immediately contacted to assess conditions. II. INTRODUCTION AllWest conducted a subsurface investigation at the subject property on April 10, The purpose of the investigation was to assess environmental concerns associated with historic land use and the proposed residential and/or commercial development of the property. The investigation program included the advancement of 14 soil borings by a direct push drilling method to assess soil and groundwater conditions. Three borings, could not be advanced past surface material. One boring was not advanced do to subsurface utility concerns. Borings were advanced to maximum depths of up to 14 feet bgs. A total of 4 groundwater and 33 soil samples were collected during this investigation. 3

7 A. Site Description The subject property is located in a light industrial area of the City of San Francisco on the west side of 3 rd Street, north of Paul Avenue. The subject property is bounded by railroad tracks to the west and north, 3 rd Street to the east, and commercial properties to the south. A site location map is presented in Figure 1. The subject property consists of a rectangular shaped parcel of land, developed with a three-story reinforced concrete block building, comprising approximately 85,000 square feet. Also present on the property are a waste water treatment building, guard house, office trailer, sugar silos, bus maintenance sheds, canopied truck scale, a trash compactor, railroad tracks and above-ground storage tanks (ASTs) associated with former property use. The northwest corner of the property has some grass growing along the railroad tracks, however the majority of the property is covered with either asphalt or concrete. B. Site History In the 1940s, the site was developed with buildings used by the United States military for barracks and offices. In 1966, the existing manufacturing building was constructed by Coca Cola USA as a syrup manufacturing plant. Coca Cola left the property in 1996 and it was later occupied by the current tenant, Western Sportswear in 1999 for clothing manufacturing. Additionally, a portion of the southern end of the property is used by Cosmostar Lines for bus parking and maintenance (circa 2002). The eastern area is used for freight truck parking, and the southeast corner of the site is used by Starving Students Moving for vehicle parking and office space. C. Geology and Hydrology The subject site is located approximately ½ mile west of San Francisco Bay. The site is underlain by silty and clayey sand. Bedrock of the Franciscan Assemblage underlies the soil at shallow depths. Based on the available geologic literature, no active fault traces traverse the subject property or surrounding areas. The closest fault is located more than one mile from the subject property. The site and vicinity slope gently to the southeast to the San Francisco Bay. The subject site lies at an approximate elevation of 35 feet above mean sea level (MSL), according to the USGS topographic map (San Francisco South Quadrangle, 1995). The depth to first groundwater in the site area is approximately 2 to 10 feet bgs. Based on topography and nearby investigations, the local groundwater flow direction is to the southeast, toward San Francisco Bay. 4

8 D. Previous Investigations Phase I Environmental Site Assessment A Phase I ESA was performed for the subject property in 1998 by PIERS Environmental Services, Inc. (PIERS, 1998). PIERS reported the subject property to be a former Coca Cola Company syrup manufacturing facility. The plant was in the process of being decommissioned at the time of PIERS ESA. Piers noted the presence of a wastewater treatment plant and sumps, water purification plant, boilers, and a UST with monitoring wells in the northwest portion of the property. In the manufacturing building, PIERS observed concrete staining at the forklift storage area located in the north end of the first floor. PIERS indicated the first floor of the building was used for shipping and receiving, and the second and third floors were manufacturing areas, including a laboratory on the third floor. Unidentified chemicals were observed on the first floor of the facility. Underground Storage Tank Removal In 1993, Groundwater Technology Government Services, Inc. (GSI) completed the removal of three 12,000-gallon heating oil underground storage tanks (USTs), installed in 1965 and 1977, and replacement with one 10,000-gallon heating oil UST (GSI, 1993). The USTs were used by Coca Cola as an emergency fuel source. During the removal process, soil samples were collected from the tank excavation, beneath piping and from stockpiled soil, and were analyzed for total petroleum hydrocarbons quantified as diesel (TPH-d) and benzene, toluene, ethylbenzene and xylene (BTEX). The results of analysis indicated the presence of 25 parts per billion (ppb) of xylenes from one sample collected from beneath piping, and 16 ppb, 44 ppb and 240 ppb of BTEX, respectively, from another sample collected from beneath the piping. Additional soil was excavated from the piping trench in the vicinity of the latter sample, but no additional soil was removed in the vicinity of the other sample because of the proximity of railroad tracks. No chemicals were detected in other soil samples. E. Purpose and Scope of Work As previously noted, the purpose of this investigation was to assess environmental concerns associated with the historic land use and proposed residential/commercial development of the property. The scope of work, as outlined in AllWest's proposal to Levin Menzies & Associates dated April 2, 2003, consisted of the following: Task 1: Prepare a site specific health/safety plan and mark soil boring locations for clearing underground utilities; 5

9 Task 2: Conduct one day of field work on the subject property. Advance up to 15 soil borings to approximately 10 feet below ground surface. Collect up to 2 soil samples per boring. Analyze selected soil samples for LUFT-5 Metals, Total Petroleum Hydrocarbons as Diesel & Motor Oil and Volatile Organic Compounds (VOCs), organochlorine pesticides, and creosote (phenols). Collect 4 groundwater samples. Analyze the water samples for Total Petroleum Hydrocarbons as Diesel & Motor Oil and VOCs. Task 3: Task 4: Oversee site restoration; and Interpret the investigation data and present the findings in a written report describing the field activities, summarize the analytical results, and provide conclusions and recommendations. III. PROJECT ACTIVITIES A. Underground Utility Clearing To avoid damage to underground utility installations during the course of the subsurface investigation, AllWest contacted Subdynamics Utility Surveys to locate and mark detected installation of subsurface utilities and pipes for field identification. The final boring locations were cleared of known underground utilities prior to drilling. B. Permit According to the City and County of San Francisco regulations, an Application for Soil Borings was submitted to the City and County of San Francisco Department of Public Health on April 2, A copy of the completed application is included in Appendix A. C. Soil Sampling Soil samples were collected using a direct push geoprobe process at 14 locations at the site for field screening and laboratory analyses. The boring advancement was performed by ECA, a licensed drilling contractor (C57 #695970) on April 10, The standard direct push advancement and sampling procedures, as presented in Appendix A, were followed. During the boring advancement operation, a representative from AllWest was present to collect soil samples, to conduct field screening, and to maintain a log of the drilling activities. The boring logs contain pertinent information on boring advancement and soil conditions, in particular the lithology of site soils and physical characteristics that suggest 6

10 potential contamination. A copy of the boring logs as well as a log legend are included in Appendix A of this report. A total of 14 borings were attempted as part of this investigation. The borings were located in areas of potential environmental concern and to obtain representative samples from areas of the property. No borings were located in the interior of the buildings at the property. Three borings, B-11, B-12 and B-15 could not be advanced past surface material material due to the presence of metal re-bar, concrete, rock and other debris. Figure 2 shows the locations of the borings. One boring, B-8, was not advanced due to underground utility concerns. D. Groundwater Sampling Groundwater was only encountered in 4 of 14 borings advanced at the site. Groundwater samples were collected in all boring that yielded water. Groundwater samples were either collected from temporary PVC well casing inserted in the borings after the completion of drilling or through the drill rods using hydropunch methodology. Groundwater samples were collected by lowering a disposal bailer into the well casing or hydropunch and partially submerging the bailer. The bailer was then brought to the surface and inspected for floating product or sheen. No sheen, floating product or odor was identified in any of the water samples. Groundwater samples were then collected with the bailer and transferred to appropriate bottles for the analysis requested. The sample bottles were then labeled, and placed in an ice chest for transport to the analytical laboratory. E. Laboratory Analyses A total of thirty four (34) soil, and (4) groundwater samples were collected during this investigation for chemical analyses. The soil samples collected from 2 feet bgs were analyzed. Soil samples collected from deeper depths were archived pending the review of soil samples results. No additional soil samples were analyzed. Groundwater samples collected from borings B-1, B-4, B-7 and B-10 were analyzed. All samples were forwarded to Severn Trent Laboratories, Inc.(STL) in Pleasanton, California for chemical analysis. STL is a California Department of Health Services (DHS) certified analytical laboratory. Selected soil samples and groundwater were analyzed for Total Petroleum Hydrocarbons (TPH) as diesel and motor oil (TPH-d and TPH-mo) by EPA Method 8015M, volatile organic compounds (VOCs) by EPA Method 8260B. Selected soil samples were analyzed for the metals; cadmium, chromium, lead, nickel, zinc by EPA Method 6010B and pesticides by EPA Method Soil samples B-13RR and B-14RR were analyzed for creosote (phenols) by EPA Method

11 IV. INVESTIGATION FINDINGS A. Subsurface Conditions In general, from below the concrete or asphalt surface and subbase, a dark brown gravelly sand with little fines was encountered. The material was dry. At depths of 4 to 8 feet the soil became lighter in color and moisture content increased. Three borings, B-11, B-12 and B-15 could not be advanced past surface material material due to the presence of metal re-bar, concrete, rock and other debris. Boring B-8 was not advanced due to underground utility concerns. Boring B-3, located in the south west corner of the property, encountered bedrock at an approximate depth of 4 feet. B. Analytical Results Soil A review of soil results indicate that TPH-d was detected at low concentrations in 7 of 9 samples tested. The highest concentration of 30 milligrams per kilogram (mg/kg) was detected in a soil sample collected from boring B-4 at a depth of 4 feet. Ten soil samples were analyzed for VOCs. No VOCs were detected in any of the samples. Seven soil samples were analyzed for organochlorine pesticides. No pesticides were detected. Phenol (creosote) was detected in the two samples analyzed for the constituent. Phenol was detected at a concentration of 0.23 mg/kg in the sample collected from B-13RR-S-2 and 0.39 mg/kg in the sample collected from B-14RR-S-2. Ten soil samples were analyzed for metals. Concentrations of cadmium ranged from 1.3 mg/kg to 3.2 mg/kg, chromium ranged from 17 mg/kg to 91 mg/kg, lead ranged from not detected (<1.0 mg/kg) to 33 mg/kg, nickel ranged for 19 mg/kg to 58 mg/kg and zinc was detected at concentrations of 22 mg/kg to 72 mg/kg. Groundwater Four groundwater samples were analyzed for TPH-d, TPH-mo, and for VOCs. TPH-d was detected in the sample collected from boring B-7 at a concentration of 130 ug/l (ug/l are equivalent to parts per billion). TPH-mo also was detected in the sample collected from B-7 at a concentration of 1,900 ug/l. TPH was not detected in the other three groundwater samples analyzed. Only two VOCs were detected, 1.1 ug/l of 1,2- Dichloroethane (1,2-DCA) in the sample collected from boring B-7 and 5.2 ug/l of Methyl tert butyl Ester (MTBE) in the sample collected from boring B-10. 8

12 Laboratory QA/QC A review of the analytical data laboratory sheets indicates that all TPH-d positive detections (one water, seven soil samples) reported that the hydrocarbon detected did not match the standard diesel pattern. The surrogate recovery for the sample B-4-S-4, was not reportable due to required dilution. The surrogate recoveries for the water sample B- 7-W were lower than QC limits due to matrix interference, and confirmed by re-analysis.. A review of the laboratory internal quality assurance/quality control (QA/QC) report indicates the method blank and sample spike data for all analyses were within the laboratory recovery limits. Therefore, the data from STL are considered to be of good quality. A copy of the laboratory analytical report and chain-of-custody record are presented in Appendix B. C. Regulatory Guidelines and Discussion of Findings To assess soil and groundwater conditions, analytical results were compared to Risk Based Screening Levels (RBSLs) compiled by the Regional Water Quality Control Board, San Francisco Bay Region (RWQCB)(December 2001), Preliminary Remediation Goals (PRGs) compiled by the United States Environmental Protection Agency (EPA) (October 2000) and to background or natural occurring levels of metals compiled by the United States Geological Survey. RBSLs were developed by the RWQCB to address environmental protection goals. These goals include protection of human health, drinking water resources, aquatic and terrestrial biota and adverse nuisance conditions. Under most conditions, the presence of chemicals at concentrations below the corresponding RBSLs can assumed to not pose a significant threat to human health and the environment. The RBSLs are conservative in nature. Concentrations of chemicals above RBSLs does not necessary indicated that impacts to human health or the environment exists or that remedial measure are required only that further evaluation is required. RBSLs are not intended to be used as a cleanup standard. PRGs were developed by Region IX of the EPA to address human health concerns regarding direct exposure with impacted soil. PRGs were primarily intended to address human exposure and do not consider impact to groundwater or ecological concerns. PRGs exist for direct contact exposure pathways for residential soil, industrial soil, ambient air and for tap water. As with RBSLs, concentrations above PRGs do not necessary indicated that impacts to human health or the environment exists or that remedial measure are required only that further evaluation is required. 9

13 Because of varying geologic conditions, background or natural occurring concentrations of some metals, including arsenic, cadmium, chromium, mercury and others can exceed health based screening levels. When this condition exists the RWQCB has stated that it is generally acceptable to use the background concentration as the screening level. The USGS has published several documents presenting average concentrations and ranges of concentrations of various metals at different environmental/geologic settings throughout the United States. Because of the presence of ultra mafic rocks (serpentine) in the Coast Ranges of California, various heavy metals can be detected at background concentrations that exceed health based RBSLs. A review of soil samples analyzed for a variety of petroleum hydrocarbon constituent indicated that only TPH-d was detected at low concentrations in 7 of 9 samples tested. The highest concentration of 30 mg/kg, which is equivalent to 30 parts per million, was detected in a soil sample collected form boring B-4 at a depth of 4 feet. The boring is located adjacent to a 10,000 gallon diesel fuel tank. The laboratory noted that the hydrocarbon detected did not match their diesel standard. The concentration detected is well below the 500 mg/kg RBSL, for TPH (middle distillates) in surface soil in a residential setting. TPH-mo was detected in 3 of 9 samples at a maximum concentration 400 mg/kg. This concentration is below the RBSL for residual fuels of 500 mg/kg. Eleven soil samples were analyzed for volatile organic compounds (VOCs). No VOCs were detected in any of the samples. Seven soil samples were analyzed for organochlorine pesticides. No pesticides were detected. Ten soil samples were analyzed for metals. Concentrations of lead, nickle, and zinc were well below their RBSLs of 200 mg/kg, 150 mg/kg, and 600 mg/kg, respectively. Additionally, the levels of these metals are also below the EPA s Region IX, PRGs of 150 mg/kg for lead, 1,600 mg/kg for nickel, and 37,000 mg/kg for zinc. Concentrations of chromium exceeded the total chromium RBSL of 13 mg/kg but are below the PRG of 210 mg/kg. A review of various reports prepared by the USGS and other investigations indicate that the concentrations detected are within ranges that would be considered background. This is especially true in areas where ultra mafic rocks (serpentine) occur, such as the Coast Ranges of California, where the property is situated. Discussion with the RWQCB indicate that the RBSL for chromium is being revised and that background levels should be substituted for the RBSL in the interim. Concentrations of cadmium slightly exceed the RBSL of 1.7 mg/kg in four of ten samples, but were below the PRG of 37 mg/kg and within ranges that would be considered background or naturally occurring. Phenols were detected in the two samples analyzed for the constituent. Phenol was detected in samples B13-RR-S-2 and B14-RR-S-2 at concentrations of 0.23 mg/kg and 10

14 0.39 mg/kg, respectively. The concentrations are well below the RBSL of 39 mg/kg and the EPA PRG of 37,000 mg/kg. Four groundwater samples were analyzed for TPH-d, TPH-mo, and for VOCs. TPH-d was only detected in the sample collected from boring B-7 at a concentration of 130 ug/kg. TPH-mo also was only detected in the sample collected from B-7 at a concentration of 1,900 ug/l. TPH was not detected in the other samples analyzed. Only two VOCs were detected, 1.1 ug/l of 1,2-DCA in the sample collected from boring B-7 and 5.2 ug/l of MTBE in the sample collected from boring B-10. Since the local groundwater is not considered a potential drinking water source and no impacts to aquatic life is anticipated, only the impact of the chemicals detected to residential indoor air quality was assessed. The RWQCB considers TPH (middle distillates) and TPH (residual fuels) (i.e. TPH-d and TPH-mo,) as non-volatile, so impact to indoor air is not a consideration. The concentrations of the volatile constituents 1,2- DCA, and MTBE are well below their RBSLs of 500 ug/l and 50,000 ug/l, respectively, for protection of indoor air quality with soils that are coarse grained and in a residential setting. No specific source has been identified for the low concentrations of TPH-d and TPH-mo detected at the property. The positive detections could be a result of surface spillage, storm water runoff infiltrations or other minor releases. The highest concentration of TPH in soil was detected in a soil sample collected from boring B-4, which is located adjacent to a 10,000 gallon UST. The groundwater sample collected from this location did not detect any TPH, therefore no large release is indicated. The highest concentration of TPH in groundwater was detected in the sample collected from boring B-7, located a parking lot which is north of the office building and east of the manufacturing building. No specific source was identified though trucks and vehicles in various states of disrepair are stored at this location. Leaks from fuel tanks, crankcases and infiltration through cracked asphalt may be the source of these chemicals. No specific source was identified for the very low levels of the solvent 1,2-DCA and the gasoline additive MTBE. 1,2-DCA is a common industrial solvent used for a variety of industrial purposes. MTBE is a gasoline additive that is highly mobile in the environment. The low levels of phenols detected may be related to residual levels of creosote left from former railroad activities or possibly related to asphalt material incorporated in the shallow soil. 11

15 V. CONCLUSIONS AND RECOMMENDATIONS Based on our understanding of the history and use of the property, results of analytical testing of soil and groundwater samples, and a review of regulatory standards no significant soil or groundwater environmental hazards were identified that would impair site development for residential use. Various chemicals including petroleum hydrocarbons and other organic constituents were detected below regulatory risk based screening levels for residential use. Metals were detected at background levels. No pesticide were detected. Further subsurface soil or groundwater investigations are not recommended at the present time. Because of the inherent limitations of our investigation, the possibility exists that undiscovered areas exist at the property that contain hazardous materials requiring further evaluation. These areas may not become evident until the building, UST, ASTs, asphalt and concrete are removed, and grading commences. Therefore we recommend the demolition and grading contractor maintain contingency plans for the possibility that potentially hazardous materials are encountered. If suspected contamination is identified or hazardous materials are encountered, AllWest should be immediately contacted to assess conditions.. VI. REPORT LIMITATIONS The work described in this report is performed in accordance with the Environmental Consulting Agreement between Levin Menzies & Associates and AllWest Environmental, dated April 2, AllWest has prepared this report for the exclusive use of Levin Menzies & Associates for this particular project and in accordance with generally accepted practices at the time of the work. No other warranties, certifications or representation, either expressed or implied are made as to the professional advice offered. The services provided for Levin Menzies & Associates were limited to their specific requirements; the limited scope allows for AllWest to form no more than an opinion of the actual site conditions. No matter how much research and sampling may be performed the only way to know about the actual composition and condition of the subsurface of a site is through excavation. The conclusions and recommendations contained in this report are made based on observed conditions existing at the site, laboratory test results of the submitted samples, and interpretation of a limited data set. It must be recognized that changes can occur in subsurface conditions due to site use or other reasons. Furthermore, the distribution of chemical concentrations in the subsurface can vary spatially and over time. The results of chemical analysis are valid as of the date and at the sampling location only. AllWest cannot be held accountable for the accuracy of the test data from an independent laboratories nor for any analyte quantities falling below the recognized standard detection limits for the method utilized by the independent laboratories. 12

16 VII. REFERENCES Environmental Protection Agency, Region 9, Preliminary Remedial Goals, October Groundwater Technology Governments Services (GSI), Final Report, Underground Storage System Closure, Coca-Cola USA San Francisco Syrup Branch, 5800 Third Street, San Francisco, California, June 8, PIERS Environmental Services, Inc., Phase I Environmental Assessment, 5800 Third Street, San Francisco, California, San Francisco Bay Regional Water Quality Control Board, Risk Based Screening Levels, in Application of Risk-Based Screening Levels and Decision Making to Sites with Impacted Soil and Groundwater, Interim Final, December 26, San Francisco Bay Regional Water Quality Control Board - Personnel communication, chromium RBSLs compared to background concetrations. 13

17 TABLE 1 SUMMARY OF ANALYTICAL RESULTS IN GROUNDWATER Sample Number B-1-W B-4-W B-7-W B-10-W TPH-mo TPH-d VOCs (ppm) Other VOCs (ppm) TABLE 2 SUMMARY OF ORGANIC ANALYTICAL RESULTS IN SOIL Sample Number TPH-mo TPH-d VOCs (ppm) B-1-S-2 B-2-S-2 B-3-S-2 B-4-S-2 B-5-S-2/2.5 B-6-S-2 B-7-S-2 B-9-S-2 B-10-S-2 B-13RR-S-2 B-14RR-S-2 Pesticides Creosote

18 Notes: 1. ND stands for not detected at or above their respective laboratory detection limit (LDL) as indicated in parenthesis. 2. TPH-g and TPH-d stands for total petroleum hydrocarbons in the gasoline and diesel range, respectively. HVOCs stands for halogenated volatile organic compounds. BTEX stands for benzene, toluene, ethylbenzene, and xylene. Concentrations for VOCs analyses and their LDLs are in units of g/kg, equivalent to parts per billion (ppb). For HVOCs, the MRL ranged between 5 and 10 ppb. 3. Analytical methods were U.S. EPA methods 6010B, 8015M, 8021B, and Analytical results reported by Chromalab. 4. EPA PRG stands for Environmental Protection Agency, Region 9, Preliminary Remedial Goals, Residential Setting for Soil, October 1, RWQCB RBSL stands for San Francisco Bay Regional Water Quality Control Board, Risk Based Screening Levels, in Application of Risk-Based Screening Levels and Decision M aking to Sites with Impacted Soil and Groundwater, Tier 1 for surface soils when groundwater is not a current or potential source of drinking water based residential land use, Interim Final, August 2000.

19 TABLE 3 SUMMARY OF METAL ANALYTICAL RESULTS IN SOIL Sample Number AWS B-1-4 AWS B-2-4 AWS B-3-4 AWS B- 4/5/6-.5 AWS B- 4/5/6-4 EPA PRG RWQCB RBSL back grou nd levels *** TT LC Arsenic ND (< 1.0 ) 15 ND (< 1.0 ) Cadmiu m ND (< 0.5 0) ND (< 0.5 0) ND (< 0.5 0) 0.63 ND (< 0.5 0) Chromiu m (Total) , Lead ** Nickel ,600 (150) * Notes: Zinc , Concentrations for metal analyses and their laboratory detection limit (LDLs) are in units of mg/kg, equivalent to parts per million (ppm). 2. ND stands for not detected at or above their respective LDL as indicated in parenthesis. 3. Analytical methods were U.S. EPA method 6010B/7000 series. Analytical results reported by Chromalab. 4. EPA PRG stands for Environmental Protection Agency, Region 9, Preliminary Remedial Goals, Residential Setting for Soil, October 1, RWQCB RBSL stands for San Francisco Bay Regional Water Quality Control Board, Risk Based Screening Levels, in Application of Risk-Based Screening Levels and Decision M aking to Sites with Impacted Soil and Groundwater, Tier 1 for surface soils when groundwater is not a current or potential source of drinking water based residential land use, Interim Final, August *The number in parenthesis is the Cal-Modified PRG (PEA, 1994). 7. **Based on Urban Area Ecotoxicity Criteria, Direct contact exposure is 400 ppm. 8. ***Based on background metal concentrations in soils in northern Santa Clara County, California. 9. If a substance in a waste equals or exceeds the TTLC level, it is considered a hazardous toxic waste

20 STANDARD DIRECT PUSH SAMPLING PROCEDURES Soil Sampling The direct push soil sampling process involves the driving into the subsurface a decontaminated two-foot Direct push soil sampler connected to 4-foot direct push extension rods. The sampler is a 1-inch inside-diameter (ID) stainless steel pipe that can accommodate four 6-inch long sampling liners to retain subsurface soils. The sampler is blocked at the bottom end with a locking driving tip until the desired sampling depth is reached. The entire sampling assembly, the sampler and the steel extension rods, is driven into the subsurface by either a truck-mounted hydraulic percussion hammer or a limited-access pneumatic percussion hammer. The sampler with liners is driven to the desired depth as additional rods are connected. At the desired sampling depth, the sampler is opened by running special thin rods down the center of the direct push extension rods to unlock the driving tip and open the sampler. A soil sample is collected by driving the assembly for another two feet. All of the sample liners are protected from cross contamination by the outer casing of the sampler. By adding sections of the extension rods, and repeating the driving process, soil cores are generated from the desired depths. At each sampling interval, a decontaminated sampler and sample liners are used to avoid cross contamination. After each sampling drive, the sampler is retrieved and the brass sample liners are removed. The soils contained in the sample liners are then classified according to the Uniform Soil Classification System and recorded on the soil boring logs. Each sample liner selected for laboratory analyses are sealed with Teflon sheets, plastic end caps, and silicon tape. The sealed sample liner is then labeled, sealed in a plastic bag, and placed in an ice chest cooled to 4 C with crushed ice for temporary field storage and transportation. The standard chain-of-custody protocol is maintained for all soil samples from the time of collection to arrival at the laboratory.

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