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HomeMy WebLinkAboutMITIGATION 4/1993~Piwar~a ~ngin~ring I I I I ,I I ~IVIL ENGINEERING SUF~VEYING EXPANDED SITE CHARACTERIZATION AND CORRECTIVE ACTION PLAN CALIFORNIA SHEET METAL 601 Eureka Street Bakersfield, California Prepared For: John McCauley c/o Byrum, Holland & Griffin 1800 - 30th Street, 4th Floor Bakersfield, CA 93301 Prepared By: PIWAREA ENGINEERING, INC. 3125 19th Street, Suite 133 Bakersfield, CA 93301 John R. Wilson, R.C.E. #23270 Registration Expires 12-31-93 April 1993 pJ.-93/SITEC~AR . RPT 31 25 1 ~lth Street. Suite 1 33 · Sekerefield. Ca. 93301-311 8 · (S015] BSl-SS0S I I I I I I I I I I I I I I I ! 1.0 2.0 3.0 4.0 5.0 TABLE OF CONTENTS INTRODUCTION ........................................... 1 1.1 Site Description ................................... 2 1.2 Project History ................................... 2 METHODS OF INVESTIGATION ............................... 8 2.1 Drilling and Soil Sampling ........................ 8 2.2 Laboratory Analysis ............................... 9 CORRECTIVE ACTION PLAN: ASSESSMENT OF IMPACTS .......... 10 3.1 3.2 3.3 3.4 3.5 3.6 Geologic Conditions ............................... 10 Subsurface Conditions ............................. 10 Hydrogeology ...................................... 10 Soil Vapor Monitoring .......................... '...11 Laboratory Analytical Results ..................... 11 Conclusions ....................................... 12 CORRECTIVE ACTION PLAN: FEASIBILITY STUDY .............. 15 CLOSURE ................................................ 18 REFERENCES Figure 1 Vicinity Map Figure 2 Site Map Figure 3 Cross Section AA' Figure 4 Cross Section BB' APPENDIX A Laboratory Reports and Chain-of-Custody I I I I I I I I I I I I I I I ,! I ! EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 1 1.0 INTRODUCTION This report presents the results of an Expanded Site Characterization performed by PIWAREA ENGINEERING, INC. (PIWAREA) at the CALIFORNIA SHEET METAL facility located at 601 Eureka Street, Bakersfield, California. PIWAREA proposed to conduct and Expanded Site Characterization associated with a release of gasoline hydrocarbons from the 550 gallon underground gasoline storage tank (UST) at the above referenced facility which were removed under Permit No. BR-0031 with the City of Bakersfield, Fire Department Hazardous Materials Division. On December 21, 1991, CALPI, INC. excavated the soil above and around the UST, and removed the tank, dispenser and associated project pipeline. Total Petroleum Hydrocarbons (TPH) as gasoline and the gasoline constituent volatile aromatics were detected in soil samples from beneath the UST. TPH as gasoline was detected at 810 mg/kg at a depth of two feet beneath the UST and at 10,000 mg/kg and 98 mg/kg in these samples, respectively. These concentrations are in excess of Regional Water Quality Control BOard (RWQCB) guidelines for gasoline hydrocarbons in the soil, and resulted in the Lead Implementing Agency (LIA) which is the City of Bakersfield Fire Department Hazardous Materials Division (BKDHMD) requesting an initial site characterization. On March 19, 1992, WILSON & ASSOCIATES, INC. (W&A) advanced six soil borings in the vicinity of the former UST to assess the vertical and lateral limits of gasoline hydrocarbons in the subsurface. Gasoline hydrocarbons were detected to a depth of less than 75 feet below surface grade. Lateral limits of the gasoline hydrocarbons appear to have been delineated to the northeast, east southwest and west. Additional lateral delineation was required by BFDHMD to the northwest and southeast. This report documents that additional investigation, consisting of three soil borings and the laboratory analysis of eight Soil samples for the presence of gasoline hydrocarbons. Ail methods employed are in compliance with regulations and guidelines set forth in California Code of Regulations (CCR) Title 22, Article 11, and Title 23, Chapter 3, California Site Mitigation decision Tree Manual, the Code of Federal Regulations (CFR) Title 29, Part 1910, Section 120, CDR Title 40, Parts 300-399, Tri- Regional Board Staff Recommendations for Preliminary Evaluation and Investigation of Underground Tank Sites, City of Bakersfield and Kern County regulations, as well as accepted professional environmental/geotechnical engineering procedures. I I I I I I I I I I I I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 2 The scope of work for this project was developed in conjunction with Mr. John McCauley representing California Sheet Metal and Mr. Ralph Huey of BFDHMD. Work performed during this phase includes the following: Development of site health and safety, and technical work plans. Drilling and sampling of three exploratory soil borings to a maximum depth of 50 feet below surface grade. Laboratory analysis of eight selected soil samples for Total Petroleum Hydrocarbons as gasoline, and the gasoline constituent volatile aromatics. Preparation conclusions, site. of this report presenting our results, and remedial action alternatives for the 1.1 Site Description The site is located at 601 Eureka Street, in the City of Bakersfield, County of Kern, California (Figure 1) The site formerly operated a gasoline storage facility for California Sheet Metal's company vehicles. The site is situated within an area of predominantly commercial properties. The overall site topography is essentially flat, with a slight fall to the south. 1.2 Project History California Sheet Metal contracted with CALPI, INC. of Bakersfield, California to remove the 550 gallon UST, gasoline dispenser, and associated product pipeline at the site. On December 17, 1992, CALPI excavated the soil above and around the UST, and removed the tank dispenser and associated project pipeline. The tanks were removed under City of Bakersfield Hazardous Materials Division Permit No. BP-0031. Soil samples were collected from beneath the UST at the direction of Mr. Joe Dunwoody with the BFDHMD. Soil samples were collected at depths of two feet and six feet beneath the center of the former UST as shown on Figure 2. These samples are designated #1 and #2. The soil samples were collected from the backhoe bucket immediately after soil excavation and stored in 2" diameter brass tubes. All soil samples were sealed with teflon (TM) liners and end caps. The samples were then labeled, handled and transported according to the United States I I I I I I I I I I I I I I I I I ! EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 3 Environmental Protection Agency (USEPA) protocol to a State of California Department of Health Services (DOHS) 'certified laboratory. Sample identification and chain-of-custody procedures were utilized for the samples to ensure sample integrity and to document sample possession from the time of collection to its ultimate destination. The sample label identified the job number, sampler, date and time of collection and sample number unique to the sample. All sampling equipment was washed with TSP~ (tri-sodium phosphate) cleanser, pre-rinsed with tap water and a final rinse of de-ionized water prior to sampling. The soil samples designated for chemical analysis were submitted to SMC Laboratories in Bakersfield, California, a State of California Department of Health Services (DOHS) certified laboratory. The soil samples were analyzed for Total Petroleum Hydrocarbons (TPH) as gasoline, and the gasoline constituent volatile aromatics, benzene, toluene, ethyl benzene, and total xylenes (BTEX) using USEPA Test Method 5030/8020. TPH as gasoline, and the gasoline constituent volatile aromatics were detected in soil samples from beneath the UST. TPH as gasoline was detected at a concentration of 810 mg/kg at a depth of two feet and 10,000 mg/kg at a depth of six feet. The volatile aromatic benzene was detected at 44 mg/kg and 98 mg/kg in these samples, respectively. Table 1 presents the analytical results for TPH as gasoline, and the gasoline constituent volatile aromatics in the two soil samples from beneath the UST. ,! EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 4 Table 1 (Analytical results expressed in milligrams per kilogram (ppm)) Sample Location Depth TPH Benzene Tolulene Ethyl Total No. Gasoline Benzene Xylenes I 1 550 Gal. UST 2' 810 44* 170, 19, 153, 2 550 Gal. UST 6' 10,000 98* 275* 23* 290* MRL N/A NA 1.0 0.005 0.005 0.005 0.005 AL N/A NA 1,000 1.0 1.0 50 50 I ND: None Detected at or above minimum reporting level (MRL) NA: Not Applicable Exceeds RWQCB recommended guidelines. Regional Water Quality Control Board recommended guidelines for contaminants in soil. the recommended guidelines were calculated using the LUFT methodology by multiplying the most stringent current federal or state water quality standards by a factor of 1,000 for gasoline, and the volatile aromatics to account for attenuation due to soil composition and distance from groundwater. AL: I I I I I I Based on the soil sampling and laboratory analysis, TPH as gasoline, and the gasoline constituent volatile aromatics were detected at concentrations in excess of RWQCB recommended guidelines for additional assessment activities. The city of Bakersfield Fire Department Hazardous Materials Division required assessment activities to determine the vertical and lateral extent of the impacted soil, and to determine whether there is a threat of these hydrocarbons impacting groundwater. California Sheet Metal contracted with Wilson and Associates, Inc. of Bakersfield, California to perform the preliminary site characterization. Drilling commenced on March 19, 1992. A total of six soil borings were drilled within this phase of soil characterization (Figure 2). Soil boring B-1 was advanced through the center of the former gasoline tank location to a depth of 90 feet below surface grade to assess the vertical extent of impacted soil beneath this probable source area. Soil borings, B-2 through B-6, were advanced radially from the tank location to assess the lateral limits of impacted soil. I I Nineteen soil samples were sent to BC Laboratories, of Bakersfield, California, a state-certified laboratory for chemical analysis. The soil samples were analyzed for Total Petroleum Hydrocarbons (TPH) as gasoline using USEPA Test Method 8015 modified, and the gasoline constituent volatile aromatics (BTEX) using USEPA Test I I I I I I I I I I I I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 5 Method 5030/8020. Seven of the samples were also analyzed for the presence of total lead using SW-6010. TPH as gasoline was detected in boring B-1 at a concentration of 6,000 mg/kg at the depths of 5 and 15 feet, 3,100 mg/kg at 30 feet, 3,000 mg/kg at 45 feet and 18,000 mg/kg at 60 feet, but not detected in the samples from 75, 80, 85 and 90 feet. TPH as gasoline was detected in boring B-2 positioned 10 feet southwest of B-1 at 12,000 mg/kg at 15 feet, and 400 mg/kg at 30 feet. TPH as gasoline was detected in boring B-3 positioned 20 feet southeast of B-1 at 30,000 mg/kg at 25 feet. TPH as gasoline was not detected in boring B-4 positioned 25 feet southwest of B-1 at 30 feet and 40 feet. TPH as gasoline was detected in boring B-5 positioned 20 feet northwest of B-1 at 7,000 mg/kg at 40 feet, but was not detected at a depth of 15 feet in this boring. TPH as gasoline was not detected in boring B-6 positioned 30 feet northeast of B-1 at 20 feet, 30 feet, and 40 feet. The gasoline constituent volatile aromatics were also detected to a depth of 60 feet below the UST and 30 feet laterally from the tank. Total lead was detected in B-1 at 39 mg/kg at a depth of 5 feet, 4.5 mg/kg at 30 feet and 4.5 mg/kg at 85 feet, in B-2 at 3.9 mg/kg at 30 feet, and in B-6 at 3.6 mg/kg at 20 feet and at 8.5 mg/kg at 40 feet. Soluble lead was detected in B-1 at 2.7 mg/1 at 15 feet. Regional Water Quality Control Board recommended guidelines for gasoline, and the gasoline constituent volatile aromatics', benzene, toluene, ethyl benzene, and total xylenes have been calculated using the LUFT methodology by multiplying the most stringent current federal or state water quality standards by a factor of 1,000 to account for attenuation due to site-specific parameters including vertical separation to groundwater, soil lithology, fractures in subsurfaces, annual average precipitation, and any direct conduits to groundwater. The recommended guidelines are 1,000 mg/kg for TPH as gasoline, 1.0 mg/kg for benzene and toluene, and 50 mg/kg for ethyl benzene and total xylenes. The State of California Title 22 Total Threshold Limit Concentration (TTLC) for lead is 1,000 mg/kg and the Soluble Threshold Limit Concentration (STLC) is 5.0 mg/1. Laboratory analytical results for the nineteen selected soil samples from the six preliminary site characterization borings are summarized in Table 2 - Summary of Analytical Results. I EXPANDED SITE CHARACTERIZATION Page No. 6 CALIFORNIA SHEET METAL Table 2 SUMMARY OF LABORATORY ANALYTICAL DATA (values in milligrams per kilogram (ppm)) INA: AL: guidelines for I Boring Depth TPH Benzene Toluene Ethyl Total Total Soluble No. Gasoline Benzene Xylenes Lead Lead I 210, 50* 1960, 39 2.7 B-1 5' 6,000* ND(>20) B-1 15' 6,000* ND(>100) 390* 170, 1290, B-1 30' 3,100, ND(>2) 86* 71, 438* 4.5 I B-1 45' 3,000*' 5* 160, 75* 390* B-1 60' 13,000, 110, 1,300, 300* 2,560* B-1 75' ND ND ND ND ND ND I B-1 80' ND ND ND ND ND B-1 85' ND ND 0.047 ND 0.014 4.5 B-1 90' ND 0.084 0.16 0.049 0.088 B-2 15' 12,000, 1,000, 1,500, 340* 2,480* I 30' 400 0.2 1.2 4.7 49 3.9 B-2 B-3 30' 30,000* 400 3,400* 800* 4,300* B-4 30' ND ND ND ND ND I B-4 40' ND ND ND ND ND B-5 15' ND 0.011 0.017 ND ND B-5 40' 7,000* 42 * 540* 160, 810, I B-6 20' ND ND ND ND ND 3.6 B-6 30' ND ND ND ND ND B-6 40' ND ND 0.008 ND 0.010 8.5 AL NA 1,000 1 1 50 50 1,000 5 i NA 1.0 0.005 0.005 0.005 0.005 2.5 0.5 MRL ND:None Detected at or above minimum reporting level (MRL) Not Applicable Exceeds RWQCB recommended guidelines. Regional Water Quality Control Board recommended Icontaminants in soil. the recommended guidelines were calculated using the LUFT methodology by multiplying the most stringent current federal or state water quality standards by a factor of 1,000 for gasoline, and the volatile aromatics to account for attenuation due to soil composition and distance Ifrom groundwater. I I I The data obtained from the tank removal operations suggest that soil impacted with gasoline hydrocarbons at concentrations in excess RWQCB recommended guidelines exist at the subject site in an area beneath the gasoline UST. The subsequent soil drilling activities indicate that gasoline hydrocarbons in excess of 1,000 mg/kg extend to a depth less than 75 feet below surface, and to a radius less than 30 feet from the location of the former gasoline UST to the northeast and the southwest. EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 7 However, the lateral limits to the northwest and southeast were not delineated by the preliminary site characterization. Upon review of the preliminary site characterization, BFDHMD requested additional drilling activities to delineate the lateral limits to the northwest and southeast of the former gasoline UST. California Sheet Metal contracted with PIWAREA ENGINEERING, INC. of Bakersfield, California to perform this expanded site characterization. I I I I I I I I I ! I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL 2.0 METHODS OF INVESTIGATION Page No. 8 2.1 Drilling and Soil Sampling Prior to commencing field operations, a technical work plan was reviewed and approved by BFDHMD personnel. Underground Service Alert was notified 48 hours in advance of the site activities. Drilling commenced on March 8, 1993 using a CME 75~ truck mounted drill rig, and equipped with 6-inch diameter hollow-stem augers. The augers were steam cleaned prior to use to minimize the possibility of cross-contamination. A total of three soil borings were drilled within this expanded phase of soil characterization (Figure 2). Soil boring, B-7, was advanced at a location 35 southeast of the gasoline tank to a depth of 50 feet below surface grade. Soil boring, B-8, was advanced at a location 30 northwest to a depth of 35 feet below surface grade. Because soil vapors were detected in this boring, B-8 was terminated at this depth, and an additional boring was advanced. Therefore, boring B-9 was advanced 15 feet west of B-8 to a depth of 50 feet. A Registered California Civil Engineer was on site to log the borings, monitor soils during drilling for contamination, and collect soil samples. Soil samples were collected at 5-foot intervals in each of the borings using a split-spoon sampler (ASTM D 3550 with shoe.similar to ASTM D 1586) equipped with three 6-inch by 2.5-inch diameter stainless steel sleeves for soil retention. The soil samples were obtained by driving the sampler with a 140-pound hammer dropping 30 inches in accordance with ASTM D 1586. The lowermost sleeve at each sample interval was screened for total organic vapors with a photo-ionization detector (PID). Headspace vapor analysis was performed by first discarding a portion of the soil retained at one end of the sleeve to produce a headspace. The sleeve was then capped and the probe of the PID was inserted through a hole in the cap and into the headspace for analysis. The middle sample sleeve was immediately sealed with Teflon6 film, capped, and placed on ice at less than 4oC for transport to a California Department of Health Services (DOHS) certified laboratory. The temperature within the ice chest was recorded at each sampling interval and recorded on the chain of custody document. Strict chain-of-custody procedures were utilized for all samples collected to ensure sample integrity and to document sample possession from the time of collection to the final destination. The temperature within the ice chest was recorded at the time that EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 9 the ice chest was delivered to the laboratory and recorded on the chain of custody document. Sampling equipment was washed with TSP (tri-sodium phosphate) cleanser, and rinsed with tap water and de-ionized water prior to sampling, between sample intervals, and between borings to minimize the potential of cross contamination. The augers were steam cleaned prior to drilling and between borings to minimize the potential of cross contamination. The borings were backfilled with a cement-bentonite slurry. 2.2 Laboratory Analysis Eight soil samples were sent to BC Laboratories for chemical analysis. The soil samples were analyzed for Total Petroleum Hydrocarbons (TPH) as gasoline, and the gasoline constituent volatile aromatics benzene, toluene, ethyl benzene, and total xylenes (BTEX) using USEPA Test Method 5030/GCFID, and USEPA Test Method 5030/8020, respectively. EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL 3.0 CORRECTIVE ACTION PLAN: ASSESSMENT OF IMPACTS Page No. 10 3.1 Geologic Conditions Regional Geology: The site is located in the southern part of the Great Valley geomorphic province. The Great Valley is a north-south trending valley, approximately 400 miles long by 50 miles wide. Surface and groundwater in the San Joaquin Valley is derived predominantly from the Sierra Nevada mountain range to the east, and is transported by five major rivers, the southern most being the Kern River. The subject site is located approximately three miles south of the Kern River. The surface of the San Joaquin Valley is composed primarily of unconsolidated Pleistocene (1.6 million to 11,000 years ago) and Recent (11,000 years ago to the present) alluvial sediments. Beneath the alluvial sediments are older, predominantly lake bed deposits. These lie unconformably on Mio-Pliocene marine sediments 'which-extend to crystalline basement at approximately 20,000 feet. Site Geology: Geologic deposits in the study area include Pleistocene alluvial sediments of the Kern River Formation, which form a homocline dipping gently to the southwest. The deposits are alluvium consisting of poorly indurated and dissected fan deposits (CDMG,1964). '3.2 Subsurface Conditions Subsurface material encountered during drilling was alluvium to the total depth of each boring. The alluvium was characterized by unconsolidated, moderate to good permeability, silt sands and well graded sands to a depth of 90 feet which is the greatest depth penetrated in the investigations. Cross Sections AA' and BB' have been prepared which integrates the geology, the location of the former underground storage tank, and the distribution of gasoline hydrocarbons in the subsurface (Figures 3 and 4). 3.3 Hydrogeology The depth to the regional unconfined aquifer is approximately 200 feet below surface grade beneath the site with the direction of groundwater flow to the south (Kern County Water Agency, 1991 Report on Water Conditions, Improvement District No. 4, February 1992). The nearest known occurrence of perched groundwater is two EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 11 miles to the southwest at a depth of 20 feet in the abandoned Kern River channel to the ancient Kern Lake bed (Kern County Water Agency, 1991 Water Supply Report, May 1992). No perched groundwater is known to exist beneath the subject site. 3.4 Soil Vapor Monitoring Soil samples collected during drilling were monitored with a photo-ionization detector (PID) to evaluate organic vapor concentrations. The PID was calibrated with an isobutylene standard of 100 parts per million (ppm) and contained an 11.8 electron volt (eV) lamp, capable of detecting benzene (9.25 eV). Boring logs present the PID readings as they were recorded in the field. 3.5 Laboratory Analytical Results TPH as gasoline was not detected in boring B-7, positioned 30 feet southeast of the former gasoline UST in the samples from 20, 30 and 50 feet. TPH as gasoline was not detected in boring B-8, positioned 30 feet northwest of the former UST at 20 feet and 35 feet. TPH as gasoline was in boring B-9, positioned 15 feet west of B-8 at 30 feet, 40 feet and 50 feet. The gasoline constituent volatile aromatics were detected at trace concentrations in the samples from B-7 at 50 feet, B-8 at 35 feet, and B-9 at 50. feet. Laboratory analytical results for the eight Selected soil samples from the three borings are summarized in Table 3 - Summary of Analytical Results. copies of the analytical reports and chain of custody documentation are presented in Appendix A - Laboratory Analytical Results. Borings B-7, B-8 and B-9 were designated B-i, B-2, and B-3 on the chain of custody document and are reported that way on the laboratory reports. I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Table 3 SUMMARY OF LABORATORY ANALYTICAL DATA (values in milligrams per kilogram (ppm)) Boring Depth TPH Benzene Toluene Ethyl Total No. Gasoline Benzene Xylenes Page No. 12 B-7 20' ND ND ND ND ND B-7 30' ND ND ND ND ND B-7 50' ND 0.064 0.029 ND 0.015 B-8 20' ND ND ND ND ND B-8 35' ND 0.079 0.11 ND 0.090 B-9 30' ND ND ND ND ND B-9 40' ND ND ND ND ND B-9 50' ND 0.11 0.027 ND 0.045 AL NA 1,000 1 1 50 50 MLR NA 1.0 0.005 0.005 0.005 0.005 I ND: None Detected at or above minimum reporting level (MRL) NA: Not Applicable *: Exceeds RWQCB recommended guidelines. iAL: Regional Water Quality Control Board recommended guidelines for contaminants in soil. the recommended guidelines were calculated using the LUFT methodology by multiplying the most stringent current federal or state water quality standards by a factor of 1,000 for gasoline, and the volatile Iaromatics to account for attenuation due to soil composition and distance from groundwater. I I I I I I 3.6 Conclusions 'The data obtained from the tank removal operations suggest that soil impacted with gasoline hydrocarbons at concentrations in excess RWQCB recommended guidelines exist at the subject site in an area beneath the gasoline UST. The preliminary site characterization indicated that gasoline hydrocarbons in excess of 1,000 mg/kg extend to a depth of less than 75 feet below surface, and to a radius of less than 55 feet from the location of the former gasoline UST to the northeast and southwest. The subsequent expanded site characterization has delineated the lateral limits to the northwest and southeast less than 50 feet from the UST. Based on the field information and analytical data, it appears that when remediation measures are undertaken, they would involve approximately 10,000 cubic yards of soil. I I I I I I I I I I I I I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 13 The gasoline constituent volatile aromatics benzene, toluene, ethylbenzene, and total zulenes have maximum Contaminand Levels (MCL's) established by the State of California for groundwater. These concentrations are 0.67 ug/1 for benzene, 100 ug/1 for toluene, 680 ug/1 for ethylbenzene, 1,750 ug/1 for total xylenes. Gasoline fuel may contain sugnificant amounts of benzene, a proven human carcinogen. Benzene is a colorless liquid with an aromatic odor. It is incompatible with strongoxidizers like chlorine or bromine with iron. The routes of expisure for benzene include inhalation, skin absorption, ingestion and skin and/or eye contact. Symptoms of exposure to benzene icnclude irritation to the eyes, nose and respiratory system, giddiness, headache, nausea, staggering gait, fatigue, anorexia, lassitude, hermatitis and abdominal pain. The potential health hazard from benzene exposure is low given the present burial of the impacted soil by at lease eight feet of overburden soil. However, the exposure to benzene would be moderate to high, if the impacted soil were to be excavated and exposed to the atmosphere. Conversely, the potential for exposure would be very low if an in-situ mitigation technology was used such as soil vapor extraction, where the extracted gasoline vapors are destroyed at and efficiency of 99% prior to emission to the atmosphere. The gasoline constituent volatile aromatics have a very high potential to evaporate at the surface given their high vapor pressures. The leaching potential of the volatile aromatics are also high, on the order of 1.3 times that of water, and is again controled by the vapor pressure and their high solubility in water. Conversely, the soil retention potential for the volatile aromatics are low. These physical characteristics make the volatile aromatics highly mobile in the subsurface, dependant primarily in the permeability of the soil, and driven by gravity, soil moisture, and vapor phase expansion. Because of the arid environment at the site, subsurface water percolation is virtually non-sxistence. At the subject site vertical gravity migration, and vapor phase lateral expansion are the primary modes of the gasoline movement. There are no surface waters within one mile of the subject site which may be threatened by this release. The first encountered groundwater aquifer beneath the subject site is the primary unconfined groundwater zone used for drinking water in the Bakersfield area. However, given that the first encountered I ! I I I i ! I ! I I I I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 14 groundwater is in excess of 200 feet below surface grade, and the presence of substantial intervening low permeability sedimentary barriers to vertical migration of gasoline hydrocarbons, there is a very low probability of the gasoline hydrocarbons impacting the groundwater. The following Table 4 presents a summary of the physical characteristics of the gasoline constituent volatile aromatics. Table 4 Physical Characteristics of the Gasoline Constituent Volatile Aromatics Chemical M.P. B.P. Solubility Vapor Pressure Density (C) (C) (ppm) (mm Hg at 20-25 C) Benzene 5.51 80 1780 75.20 Toluene 95 110.6 537 21.84 Ethylbenzene -93.9 136.2 167 7.08 O-Xylene -29 144.4 162 6.16 M-Xylene -53.6 139.1 162 6.16 P-Xylene -13.2 138.4 162 6.16 0.879 0.867 0.867 0.880 0.864 0.861 I I I I I I I I i I I I I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL 4.0 CORRECTIVE ACTION PLAN: FEASIBILITY STUDY Page No. 15 At least four options for remediation for the soil are applicable to the site; 1. natural in-situ biodegradation, 2. excavation and transporation of soil to an approved landfill or recycling facility, 3. excavation and surface bioremediation, and 4. in- situ vapor extraction. Option 1: Natural In-Situ Biodegradation Natural in-situ biodegradation is appropriate in these circumstances and is protective of the environment given the foollowing facts: (1) the small volume of contamination; (2) the nearly 150 foot distance of vertical separation between the impacted soil and the first occurrence of groundwater (at approximately 200 feet); (3) the existence of intervining sedimentary barriers to migration; and (4) the ability of natural processes to biodegrade the contamination without risk to groundwater or people. Furthermore, because this option will not require contamination to be exposed to the atmosphere, transported long distances to a hazardous materials landfill, occupy scarce hazardous waste landfill space, or become exposed to people or the environment, this option poses a low risk to the environment and human health. Option 2: Excavation and Offsite Disposal or Recycling In option 2, contaminated soil would be excavated to a depth 60-75 feet where the site assessment had indicated that the limits of concentration in excess of the recommended guildlines would be reached, and laterally 35 feet from the the gasoline tank Because the impacted soil extends to a gignificant depth, and there are on- site structures and nearby roadways'which limit the boundaries of the excavation, this option is likely not feasible. The decision whether the soil may be transported to a recycling facility or required diposal at a hazardous waste landfill depends on the concentration of contaminants in the soil after is tis stockpiled. If the concentrations exceed the recycling facilities' permit specifications, then disposal at a hazardous waste landfill would be required. Judging from the findings of this study, however, it appears that the soil might qualify to be recycled at one of several approved facilities. Whether the soil would be recycled or disposed of in a landfill, this option would be exceptionally expensive. In light of the depth of the impacted soil, and the facts that this option would expose the contamination to the atmosphere during and after excavation, and would require transporting contamination long I I I I I I I I I i I I I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 16 distances to a landfill or recycling facility, PIWAREA ENGINEERING does not recommend this option. Option 3: Excavation and Surface Bioremediation In option 3, the impacted soil would again be excavated, but then would be treated on-site to non hazardous concentrations through the prcess of bioremediation. Surface bioremediation has been shown to be particularily successful in the San Joaquin Vallen given the high temperatures, and low relative humidity, with a probable time frame of less than six months. As with option 2, the depth of the impacted soil, and the fact that it would expose the contamination to the atmosphere during and after excavation, makes it undesirable in light of the circumstances at the site. Option 4: In-Situ Vapor Extraction Option 4 would invole treating the soil through in-situ vapor extraction. This option would allow the soil to remain in place, and the volatile gasoline hydrocarbons to be extracted through wells drilled into the impacted soil. The effectiveness of this option woild be dependant on the ability of an air flow to be Created throughout the zone of impacted soil, permitting the volatile gasoline hydrocarbons to volatize, and then be extracted through the wells. The stratigraphy and high soil permeabilities at this site lends itself to vapor extraction. PIWAREA ENGINEERING's experience in vapor extraction of volatile gasoling hydrocarbons from high permeability soils indicated that the timeframe for successfull treatment would be approximately six to nine months. The cost for in-situ vapor extraction would be approximately $100,000 to $150,000. In the preliminary site characterization, Wilson and Associates recommended that the best available remediation technology is to treat the soil to non hazardous concentrations through the process of In-Situ soil vapor extraction. The BFDHMD concurred with this recommendation in their letter dated November 16, 1992. PIWAREA ENGINEERING also recommends in-situ soil vapor extraction as the best available technology to reduce the concentration of gasoline hydrocarbons in the soil to below RWQCB recommended guidelines. The client should be aware that the State of California has been mandated to have a leaking underground storage tank cleanup fund to cover site investigation and remediation expenses above $10,000 but not to exceed $1,000,000. PIWAREA ENGINEERING personnel will assist the client in complying with the qualifying requirements for I I I I I I I I I I I I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL Page No. 17 the fund. Proper and complete documentation of tank operation permits, tank abandonment permits, and compliance with regulatory requests for assessment and remediation is critical for both qualification, and prioritization of your site within the funding system. EXPANDED SITE CHARACTERIZATION Page No. 18 CALIFORNIA SHEET METAL 5.0 CLOSUR_____~E This report has been prepared for the exclusive use of California Sheet Metal as it pertains to the location of the former 550 gallon UST located at 60~ Eureka Street, Bakersfield, California. The results contained in each verbal or written report are based upon the information acquired during the assessment. It is possible that variations could exist beyond points explored during the course of the investigation. Also, changes in conditions found could occur at some time in the future due to contaminant migration, variations in rainfall, temperature, and/or other factors not apparent at the time of the field investigation. This report should not be regarded as a guarantee that no further contamination, beyond that which may have been detected within the scope of this study, is present.on or beneath the site. If additional information regarding the possible presence or past use of hazardous materials at the site becomes available, then the need for further field investigation should be re-evaluated. Similarly, if suspected contamination is encountered during earthwork or construction activities, a qualified engineer or geologist should be on-site to monitor the soils and collect samples for laboratory analysis. The services performed by PIWAREA ENGINEERING were conducted in a manner consistent with the level of care and skill ordinarily exercised by members of our profession currently practicing under ~imilar conditions in the state of California. No other warranty is expressed or implied. Thank you for this opportunity to be of service.-If you have any this Or the information contained questions regarding report herein, please contact this office at your convenience. Respectfully submitted, PIWAREA ENGINEERING, INC. J~n R. Wilson, R.C.E. #23270 //,~?/~O' - ~-~ ~_ Registration Expires 12-31-93 ~&~~ ~ 'NO No..~z/u J,~tt23270 I I I I I I I I I I I I I I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL REFERENCES California Division of Mines and Geology, 1964, Geologic Map of California, Bakersfield Sheet. Kern County Water Agency, 1991, Water Supply Report, September 1992. Kern County Water Agency, 1991, Report on Water Conditions-Improvement District No. 4, February 1992. Tri-Regional Board Staff Recommendations fOr Preliminary Evaluation and Investigation of Underground Tank Sites California Water Resources Control Board, 1989, LUFT Manual Guidance Document. California Water Quality Control Board-Central Valley Region, Compilation of Water Quality Goals, October 1991. I I I I I ! I I I i I i I I I I I I EXPANDED SITE CHARACTERIZATION CALIFORNIA SHEET METAL APPENDIX A Laboratory Reports and Chain-of-Custody m m m m m m m m m m m m m m m m m m m m C m NORTH SCALE'I'% I0' W TM II II · 'IFIGURE 3 I I I I I I I I I I I I I I I I I I I AbPENDIX A Laboratory R~ports and Chain-of-Custody RECEIVED I I I I I I I I I I I I i I I I I Petroleum Hydrocarbons MAR g,~ 1993 W,Lov,, ~ no~vC. INC. WILSON &ASSOCIATES '2217 "E" STREET BAKERSFIELD, CA '93301 Attn.: JOHN R..WILSON 323-6460 Date of Report: 03/22/93 Lab ~: 93-02148-1 Sample Description: CALIF. SHEET METAL: B-1 ® 20' (SOIL) 03-08-93 ® 0900 SAMPLED BY J.R. WILSON TEST METHOD: TPH by D.O.H.S. / L.U.F.T. Manual Method - Modified EPA 8015 Individual constituents by EPA Method 5030/8020. Sample Matrix: Soil Date Sample Collected: 03/08/93 Constituents Benzene Toluene Ethyl Benzene Total Xylenes Total Petroleum Hydrocarbons (gas) Date Sample .Received ® Lab: 03/08/93 Date Analysis Completed: 03/19/93 Analysis Reporting Results Units None Detected None Detected None Detected None Detected None Detected ma/kg mg/kg ma/kg mg/kg ma/kg Minimum Reporting Level 0.005 0.005 0~005 0.0!: California D.O.H.S. Cert. ~1186 Department Supervisor . 41 OD Atlas Ct. · Bakersfield, CA 93308 · (805) 327~491 I · FAX (805) 327-1918 LABORATORIES, InC. Bakersfield, Califdrnia 93308 CHAIN OF CUSTODY - . ~ '' o o 0  ~ .. · ' ~ ~ ~ ~ ~ ~ ~ ~ ~ Matrix(S) Soil (SE) Sludge ~ ~ (W) Water (Other) ~ ~ ~ ~ .~. ~ ~ ~ ~ ~ Samples rec. cold (y/n) ~ Custody Seals (y/n) '" ~ Date & Time ~ q q m q / ~umbor and ~ 5' ~'~ ~ ~ , ~ Container Type I I I I I I I ! I I I I I ! I I I Petroleum Hydrocarbons WILSON & ASSOCIATES 2217 "E" STREET BAKERSFIELD, CA 93301 Attn.: JOHN R. 'WILSON 323-6460 Date of Report: 03/22/93 Lab #: 93-02148-2 Sample Description: CALIF. SHEET blETAL: B-1 @ 30' (SOIL) 03-08-93 ® 0915 S;LMPLED BY J.R. WILSON TEST METHOD: TPH by D.O.H.S. / L.U.F.T, Manual Method - Modified EPA 8015 Individual constituents by EPA Method 5030/8020. Sample Matrix: Soil Date Sample Collected: 03/08/93 Date Sample Received ® Lab: 03/08/93 Date Analysis completed: 03/19/93 Analysis Reporting Constituents Results Units None Detected mg/kg None Detected mg/kg None Detected mg/kg None Detected mg/kg None Detected mg/kg Benzene Toluene Ethyl Benzene Total Xylenes Total Petroleum Hydrocarbons (gas) Minimum Reporting Level 0.005 0.005 0.005 0.'01' California D.O.H.S. Cert. ~1186 Department Supervisor 4100Ar~as CC. · Bakersfield, CA 93306) · (8C)~) 327~491 I · FAX (BCb--] 327-1 91 8 [OI~ATORIES I i ! I Petroleum Hydrocarbons WILSON & ASSOCIATES 2217 "E" STREET BAKERSFIELD, CA 93301 Attn.: JOHN R. WILSON 323-6460 Date of Report: 03/22/93 Lab ~: 93-02148-4 Sample Description: CALIF. SHEET METAL: B-1 ® 50' (SOIL) 03-08-93 ® 0945 SAMPLED BY J.R. WILSON TEST METHOD: TPH by D.O.H.S. / L.U.F.T~ Manual Method - Modified EPA 8015 Individual constituents by EPA Method 5030/8020. Sample Matrix: Soil Date Sample Collected: 03/08/93 Date Sample Received ® Lab: 03/08/93 Date Analysis Completed: 03/19/93 I I' I Minimum Analysis Reporting Reporting Constituents Results Units Level Benzene 0.064 mg/kg 0.'005 Toluene 0.029 mg/kg 0.005 Ethyl Benzene None Detected mg/kg 0~005 Total Xylenes ~0.015 mg/kg 0.'011 Total Petroleum Hydrocarbons (gas) None Detected mg/kg 1. I I I I I California D'.O.H.S. Cert. #1186 Department Supervisor 410OAtlas Ct. · Bakersfield, CA 93308 · (805) 327~4911 · FAX (805) 327-1 @18 I_~OI~ATOF~IES I I I I Petroleum Hydrocarbons WILSON & ASSOCIATES 2217 "E" STREET BAKERSFIELD, CA. 93301 Attn.: JOHN R. WILSON 323-6460 Date of Report: 03/22/93 Lab ~: 93-02148-5 Sample Description: CALIF. SHEET METAL: B-2 ® 20' (SOIL) 03-08-93 ® 1030 SAI~PLED BY J.R. WILSON TEST METHOD: TPH by D.O.H.S. / L~U.F.T~ Manual Method - Modified EPA 8015 Individual constituents by EPA Method 5030/8020. Sample Matrix: Soil I I I I I' i I Date Sample Collected: 03/08/93 Constituents Benzene Toluene Ethyl Benzene Total Xylenes Total Petroleum Hydrocarbons (gas) Date Sample Received ® Lab: 03/08/93 Date Analysis Completed: 03/19/93 Analysis Reporting Results Units None Detected mg/kg None Detected mg/kg None Detected mg/kg None Detected mg/kg None Detected mg/kg Minimum Reporting Level 0.005 0.005 0.005 I I I I California D.O.H.S. Cert. $1186 Department Supervisor 4100Atlas Ct. · Bakersfield, CA 93308 · (805) 327~491 I · FAX (805) 327-191B Petroleum Hydrocarbons WILSON & ASSOCIATES 2217 "E" STREET BAKERSFIELD, CA' 93301 Attn.: JOHN R. WILSON 323-6460 Date of Report: 03/22/93 Lab ~: 93-02148-7 Sample Description: CALIF. SHEET METAL: B-2 @ 35' (SOIL) 03-08-93 ® 1100 SAMPLED BY J.R. WILSON TEST METHOD: TPH by D.O.H.S. / L.U.F.T~ Manual Method - Modified EPA 8015 Individual constituents by EPA Method 5030/8020. Sample Matrix: Soil Date Sample Collected: 03/08/93 Constituents Benzene Toluene Ethyl Benzene Total Xylenes Total Petroleum. Hydrocarbons (gas) Date Sample Received ® Lab: 03/08/93 Date Analysis Completed: 03/19/93 Analysis Reporting Results Units 0,079 mg/kg 0,11 mg/kg None Detected mg/kg 0,090 mg/kg None Detected mg/kg Minimum Reporting Level 0;005 .~o.;0o5 0;'00.5 0 ,'01~ 1, California D.O.H.S. Cert. #1186 Department Supervisor 41 O0 Atlas Ct. · Bakersfield, CA 93308 · (805) 327~4911 · FAX (805) 327-1 918 IL~BO~ATORIES Petroleum Hydrocarbons WILSON & ASSOCIATES 2217 "E" STREET BAKERSFIELD, CA 93301 Attn.: JOHN R. WILSON 323-6460 Date of Report: 03/22/93 Lab #: 93-02148-8 Sample Description: CALIF. SHEET METAL: B-31 ® 30' (SOIL) 03-08-93 @ 1200 SAMPLED BY J.R. WILSON TEST METHOD: TPH by D.O.H.S. / L.U.F.T~ Manual Method - Modified EPA 8015 Individual constituents by EPA Method 5030/8020. Sample Matrix: Soil Date Sample Collected: 03/08/93 Constituents Date Sample Received ® Lab: 03/08/93 Date Analysis Completed: 03/19/93 Analysis Reporting Results Units Minimum Reporting Level Benzene None Detected mg/kg 0.005 · Toluene None Detected mg/kg 0.005 Ethyl Benzene None Detected mg/kg 0'~005 Total Xylenes None Detected mg/kg 0.01; Total Petroleum' ~ Hydrocarbons (gas) None Detected mg/kg 1. California D.O.H.S. Cert. ~1186 Department: Supervisor 4100Atlas Ct. · Bakersfield, CA 93308 · (805) 327~91 I · FAX (805-] 327-1918 Petroleum Hydrocarbons WILSON.& ASSOCIATES 2217 "E" STREET BAKERSFIELD, CA 193301 Attn.: JOHN R. WILSON 323-6460 Date of Report: 03/22/93 Lab %: 93-02148-9 sample Description: CALIF. SHEET METAL: B-3 ® 40' (SOIL) 03-08-93 ® 1215 SAMPLED BY J.R. WILSON TEST METHOD: TPH by D.O.H.S. / L.U.F.T: Manual Method - Modified EPA 8015 Individual constituents by EPA Method 5030/8020. Sample Matrix: Soil Date Sample Collected: 03/08/93 Date Sample Received ® Lab: 03/08/93 Date Analysis Completed: 03/19/93 Constituents Analysis Reporting Results Units Minimum Reporting Level I I Benzene Toluene Ethyl Benzene Total Xylenes Total Petroleum Hydrocarbons (gas) None Detected mg/kg None Detected mg/kg None Detected mg/kg None Detected mg/kg None Detected mg/kg 0.005 ,<0.005 0~005 0.01, 1. I I I California D.O.H.S. Cert. %1186 Department Supervisor 4100Atlas Ot.. Bakersfield, (~A 93308 · (80b--) 327~491 I · FAX (E)Ob--) 327-191B ! ILABORATORIES I I i Petroleum Hydrocarbons WILSON & ASSOCIATES 2217 "E" 'STREET . BAKERSFIELD, CA 93301 Attn.: JOHN R. WILSON 323-6460 Date of Report: 03/22/93 Lab ~: 93-02148-10 Sample Descript£on:~ CALIF. SHEET METAL: B~3 ® 50' (SOIL) 03-08-93 ® 1230 SAMPLED BY J.R. WILSON TEST METHOD: TPH by D.O.H.S. / L.U.F.T. Manual Method-- Modified EPA 8015 ~ Individual constituents bY. EPA Method 5030/8020. ' ~i.-~i{ Sample Matrix: Soil Date Sample Collected: 03/08/93 Date Sample Received ® Lab: 03/08/93 Date Analysis Completed: 03/19/93 Constituents Analysis Reporting Results Units Minimum Reporting Level Benzene Toluene Ethyl Benzene Total Xylenes Total Petroleum Hydrocarbons (gas) 0.11 mg/kg 0.027 mg/kg None Detected mg/kg 0.045 mg/kg None Detected mg/kg 0. 005 0.,005 0.005 0.01' 1. I I I California D.O.H.S. Cert. #1186 Department: Supervisor 4100Atlas CC. · Bakersfield, GA 93308 · (BOb-) 327~491 I · FAX (BOb--) 327-1918