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REVISED August, 1988 ESSO TUTU SERVICE STATION SOIL GAS VAPOR SCREENING SURVEY REPORT ST. THOMAS, U.S.V.I. JUNE 14, 1988 PREPARED FOR ESSO STANDARD OIL S.A. LTD. PREPARED BY BELGODERE & ASSOCIATES INC, 142 F.D. ROOSEVELT AVENUE BROOKMAN ROAD HATO REY, PUERTO RICO 00918 ST. THOMAS, (809) 756-6930 U.S.V.I. 00802 (809) 759-8818 (809) 774-1648 *64437* 64437 TABLE OF CONTENTS 1.0 Project Summary . . . . . . . . . . . . . . . . . . . . 1 2.0 Project Background . . . . . . . . . . . . . . . . . . 3 2.1 Location and purpose of study .......... 5 2.2 Hydrogeological setting . . . . . . . . . . . . . 5 3.0 Method of Investigation ................ 10 3.1 Soil Vapor Screening Survey . . . . . . . . . . . 10 4.0 Results of Soil Gas Survey . . . . . . . . . . . . . . 15 4.1 Aromatic Hydrocarbons . . . . . . . . . . . . . . 15 4.2 Area 1 . . . . . . . . . . . . . . . . . . . . . . 22 4.3 Area 2 . . . . . . . . . . . . . . . . . . . . . . 28 4.4 Area 3 . . . . . . . . . . . . . . . . . . . . . . 28 5.0 Chlorinated Hydrocarbons . . . . . . . . . . . . . . . 29 6.0 Recommendations . . . . . . . . . . . . . . . . . . . . 34 LIST OF FIGURES Figure 2.1.1 Site Location Map . . . . . . . . . . . . . . 6 Figure 2.1.2 Map of Central Tutu Area, St. Thomas, showing the Esso Tutu Service Station (ETSS) and nearby facilities . . . . . . . . 7 Figure 3.1.1 Sampling Location Map . . . . . . . . . . . . 12 Figure 4.1.3 Distribution Map of Benzene, Toluene, Xylenes 21 Figure 4.1.4 Contour Map of Soil Vapor Concentrations for Total BTEX . . . . . . . . . . . . . . . 23 Figure 4.1.5 Contour Map of Soil Vapor Concentrations for Benzene . . . . . . . . . . . . . . . . . 24 Figure 4.1.6 Contour Map of Soil Vapor Concentrations for Toluene . . . . . . . . . . . . . . . . . 25 Figure 4.1.7 Contour Map of Soil Vapor Concentrations for Xylenes . . . . . . . . . . . . . . . . . 26 Figure 4.2.1 Elevation Measurements . . . . . . . . . . . 27 Figure 5.0.2 Distribution Map of Chlorinated Hydrocarbons Results . . . . . . . . . . . . 33 LIST OF TABLES 2.2.1 Water Level Measurements 4.1.1 Concentrations of Aromatic Hydrocarbons found in Soil Vapors . . . . . . . . . . . . . . . . 17 4.1.2A Drift Point, Highest Concentration of Aromatic Hydrocarbon Vapors . . . . . . . . . . . . . . . . . 19 4.1.2B Drift Point, Highest Concentration of Chlorinated Hydrocarbon Vapors . . . . . . . . . . . . . . . . . 20 5.0.1 Concentrations of Chlorinated Hydrocarbons found in Soil Vapors . . . . . . . . . . . . . . . . 31 APPENDIX Appendix I. Preliminary Site Investigation. Appendix II. Operational Procedures Audit. TUT OO3 Ofc7l 1.0 PROJECT SUMMARY On June 8, 1987, the reporting of the presence of chemicals in one of the water wells in the Tutu area of St. Thomas, US Virgin Islands (USVI) prompted the Department of Planning and Natural Resources (DPNR) of the USVI and the US Environmental Protection Agency Region II to conduct a sampling investigation of all the production wells in the area. Sample analyses revealed the presence of chlorinated & aromatic hydrocarbons, among other chemicals, in the water of some of the Tutu area wells. The highest concentration of dissolved volatile organic compounds was reported to be found at the Tillet Garden well located approx. 300 ft. upgradient from the Esso Tutu Service Station (ETSS). Because of the reported presence of aromatic hydrocarbons, DPNR/EPA issued Administrative Orders to two of the service stations in operation in the immediate vicinity (eg. Esso and Texaco). This administrative order required the preparation and submittal of a Work Plan designed to investigate possible product releases. In September, 1987, Esso Standard Oil S.A. Ltd. (ESSO) retained Belgodere & Associates, Inc. (BAI) to prepare the required soil vapor sampling plan for the Esso Tutu Service Station. After on-site evaluations and discussions between DPNR/EPA, CDM-Federal Programs Corporation (CDM-FPC, EPA's Contractor), BAI and ESSO, the Work Plan for this investigation was drafted and approved on March 17, 1988. On April 5, 1988 TUT BAI personnel began the soil vapor screening survey for benzene, toluene, ethylbenzene and xylenes (BTEX). The initial screening investigation was completed on April 23, 1988. The survey results show an area of petroleum hydrocarbon vapor concentrations with levels ranging from not detectable (ND) to 1 ,675 ppm of benzene in the south and central portion of the ETSS facility. Immediately to the south of the ETSS property the vapor concentrations were significantly reduced. A second area of petroleum hydrocarbon vapor concentrations ranging from ND to 128 ppm of benzene was obtained offsite in an area adjacent to the west and southwest of the station. A third area of petroleum hydrocarbon vapor concentrations ranging from ND to 2.5 ppm of benzene was found throughout the remaining sampling stations. Although chlorinated compounds are not associated with motor fuel storage and dispensing operations, DPNR-EPA requested ESSO to include in the soil vapor screening survey analyses of the following chlorinated hydrocarbons: dichloroethylene (DCE), tetrachloroethylene (PCE), trichloroethylene (TCE). This request was made by the agencies because chlorinated compounds were reported in the groundwater and found in a previous soil vapor survey conducted in the area. This investigation showed that chlorinated hydrocarbon vapors were present in most of the points sampled. A soil vapor survey was conducted at the Texaco service station. The Texaco service station is located 600 ft. upgradient from the ETSS facility. A report of their finding was submitted on December 18, 1987, to the regulatory agencies. 2.0 PROJECT BACKGROUND A number of water wells have been shut down by the Department of Planning and Natural Resources of the USVI (DPNR) and the Environmental Protection Agency Region II, New York (EPA) as a result of reported groundwater contamination in the Tutu area of St. Thomas, USVI. DPNR/EPA believe that among the possible sources of aromatic hydrocarbons found in the groundwater may be the gasoline stations which operate or had operated in the Tutu area. Esso, as the owner of a gasoline service station located in the Four Winds Shopping Center at the Tutu Area of St. Thomas, was issued an administrative order by DPNR to investigate the site. Esso contracted BAI to conduct the investigation and to issue a report on the findings. ESSO and BAI representatives met several times with EPA's Project Managers, Mr. Charles Dolan, who was subsequently replaced by Ms. Caroline Kwan; DPNR's representatives, Ms. Francine Lang and Gregory Rhymer; and the Project Officer from Camp, Dresser & McKee Federal Programs Corporation (CDM-FPC), Mr. Scott B. Graber, to discuss the technical approach to be used in the investigation. The initial proposed work plan submitted by ESSO to DPNR-EPA in September 1987 included drilling, collection and analyses of soil samples, installation of monitoring wells and the collection and analyses of groundwater samples. DPNR-EPA rejected ESSO's original proposed investigation plan and suggested that a soil vapor screening survey be performed. ESSO presumes that the findings of the soil vapor survey conducted at the ETSS site will be compared to the results of the soil vapor survey previously conducted to the north around the Texaco facility. A second work plan was submitted and reviewed by DPNR/EPA. Approval of the plan was obtained on March 17, 1988. The soil vapor screening survey started on April 5 with DPNR/EPA u n d e r s t a n d i n g of the project l i m i t a t i o n s caused by the unavailability of low end BTEX standards of 1, 10, 100 ppb. TUT OO3; 0&75 2.1 LOCATION AMD PURPOSE OF STUDY The Esso Tutu service station is located in St. Thomas USVI on the west side of road No. 38 in the Tutu area, at the south eastern corner of the Four Winds Shopping Center parking lot (see figure 2.1.1). Nearby facilities include a Texaco gasoline station (600' NNE), the LAGA building (formerly a clothing manufacturing plant, 875* NE) , the Four Winds Shopping Center (75* W), Vitelco building (local telephone company, 100' E) , Mike's Paint Store (250' ENE) and a private Lutheran school (400' S) (see figure 2.1.2) . From April 5 through 23, 1988, BAI personnel conducted a soil vapor screening survey in and around the Esso Tutu Service Station. The purpose of the soil vapor screening survey was to determine the presence and areal extent of hydrocarbon vapors in the soil matrix. It should be pointed out that soil vapor values cannot be directly equated to concentrations of dissolved hydrocarbons in the ground water. 2.2 HTDROGEOLOGICAL SETTING According to information obtained from "Soil Survey of the U.S. Virgin Islands, 1970 Soil Conservation Service Report", issued in August 1970, the area is described as a network of terraces and alluvial fans sloping gently to moderately toward the south. Soil deposits consist of stratified sands, gravels SuUC«y OwMtcap Cay S*H C»if w«tl Botany ~ ' LNtto SI Thomain 5 ItUnd FIGURE 2.1.1 (NVIflONMCNIAl-CIO COMSUlTANfl CARIBBEAN SITE LOCATION FIGURE 2.1.2 L, MAP OP CENTRAL TUTU AREA NORTH 100 FEET b-WEtt BELGODERE «• ASSOCIATES and clays with a permeability of 0.20 to 0.63 in./hr. Soil strata thickness around the site location varies from exposed bed rock on side of hills to over 20 ft. in alluvial deposits. Based on topographic and structural information obtained from "Geology of St. Thomas and St. John, U.S. Virgin Islands" by Thomas W. Donnelly (NSF, G-114407), the bedrock in the upper turpentine run basin is the Louisenhoj formation. Extensive deformation and fracturing has occurred due to later tectonic activities. Local groundwater flow in these rocks is controlled by fractures underlying the site area. The regional direction of groundwater flow is generally to the south. Based on discussions with local water well driller (Poly Caribe), depth of groundwater at the Four Winds Shopping Center well (located 25 ft. north of the Service Station) and the Tillett Water Well (located 250 ft. to the northeast), is reported to be between 15 and 20 ft. during the rainy seasons when the water table is high and pumping of commercial and residential water wells is low. The local water table has been previously observed to drop below 90 ft. as a result of high water extraction during extended drought periods (see table 2.2.1). Water supply wells in the vicinity are generally drilled to depths between 100 to 200 ft. below land surface. 8 vo * z* r.?.?&* *??f? fsj]?? 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IS 1 '.t C 1 Tab! w.n :i t Owntr. — '. TlUet. ' Location. --Ut 11* 10' 29*. long t«* S31 1C*. D^JcnnUon. — Drilled watc'.UbU proclucUon well. ? (D fi!|!l t - ,:!«7f i w < !i ; > • =|J 5 ? • H J T - ? rU ^ ! - |— t +* • '• -7 s §ii» S'-f 5- U!2 15?! Z. o *" • <T * «T — * » . a s. -IV C" ? i *A 0" M €J _,- * w •-• n «o C* 0 • * a> 3.0 METHOD OF INVESTIGATION A preliminary field and literature investigation was performed by BAI personnel during the months of September through December 1987 to allow for optimization of resources during soil vapor extraction and testing operations. The results of the preliminary site investigation were reported in section 3.4 of the Esso Tutu Service Station Soil Vapor Investigation Plan, dated January 11, 1988 (See Appendix I). 3.1 SOIL VAPOR SCREENING SURVEY The soil vapor screening survey was conducted in and around the ETSS facility between April 5 and April 23, 1988. The screening survey consisted of obtaining soil vapor samples at different locations and depths, and performing on-site analyses of the samples using two HNU-301 gas chromatographs (GC) owned and operated by BAI. Soil vapor sampling and field analyses were performed as outlined in the Esso Tutu Service Station Soil Vapor Investigation Plan and the Esso Tutu Service Station QA/QC Plan dated January 11, 1988 (second revision), with modifications based on field conditions and requests by DPNR/EPA/CDM. The soil vapor sampling stations consisted of 11 points located inside the service station property and 33 points located outside the facility. Samples at each station were taken from depths between 2-4 ft. and 6-8 ft. where local conditions allowed. A sampling location map is presented in figure 3.1.1. 10 0681 Soil vapor samples were collected by driving a 5/8 inch diameter hollow stainless steel probe to the appropriate depth by hand with a slide hammer. Once the desired depth was achieved, 5 to 10 liters of soil vapor from around the shield point were extracted with the use of a 1,700 cc/min battery operated vacuum pump (with built-in rotameter) . The pump was attached to the probe with a tygon hose containing a septum sampling port and a vacuum gauge. Gas tight syringes were inserted through the septum port to collect two to four 2.5 milliliter to 25 microliter vapor samples for immediate on-site analysis. Samples were analyzed for aromatic hydrocarbons (BTEX), which typically comprise the major constituents of commercial gasoline. Chlorinated hydrocarbons TCE, PCE, and DCE, although not typically found in gasoline were also analyzed. 11 TUT 003 0682 As previously mentioned, two GC's were used for the field analyses. GC No. 1 was equipped with a photo ionization detector (PID) and a flame ionization detector (FID) and a 10% TCEP, Chromosorb PAW 8' x 1/8" ss pack column. GC No. 2 was equipped with a FID and a 3% SE 30 Chromosorb WAW 6' x 1/8" ss pack column. Both GC's were equipped with Spectra Physics model SP4290 integrators for data reduction. Initially, GC No. 1 was set to selectively identify aromatic hydrocarbons and GC No. 2 to selectively identify chlorinated hydrocarbons. Due to constant voltage fluctuations ranging from 92 to 125 volts, and daily power outages during the first days of the investigation, the PID/FID GC and both integrators failed to perform as designed. The PID was atfected by decreased sensitivity, and the integrators used to calculate peak areas were malfunctioning which required later manual data reduction. The voltage irregularity was minimized by installing a Topaz model 02906-02P3 power conditioning unit. However, even with this unit, the voltage fluctuations damaged GC No. 1, and all the samples were subsequently analyzed using GC No. 2 only. In an effort to eliminate voltage variations and power outages, an on-site generator (Onan 3.5 kw) was employed which produced a constant 145 volts until breakdown occurred after 5 days of use. 13 TUT O03 0683 Analyses of the soil vapor samples collected at the selected drift point location for this study showed that the range of concentrations were several orders of magnitude. Due to the range of results, and unavailability of the low end BTEX standards, it was agreed by all representatives that sufficient information for the survey was obtained when the aromatic hydrocarbon vapor concentrations were below 1 ppm for each BTEX component. The sampling boundaries were thus finalized when sample results were below 1 ppm. This replaced the previous agreement that the soil vapor survey limits were reached when the concentrations were below three times background. 14 TUT 4.0 RESULTS OF SOIL GAS SURVEY 4.1 AROMATIC HYDROCARBONS Table 4.1.1 presents the highest BTEX analyses results of the sequential samples obtained from each soil vapor sample point. Sequential samples were taken during the survey instead of duplicate split samples originally proposed in the Work Plan. Copies of all chromatograms and daily calibration curves are presented in a separate supplement entitled: "Photocopies of Original Gas Chromatograms and Calibration Curves". At the drift point selected for the ETSS soil vapor investigation, repeated samples were taken by inserting separate probes within an area of less than 150 square feet to determine whether soil vapor values varied significantly over time and short distance. A total of 7 drift point values for BTEX and chlorinated hydrocarbons were obtained during 7 of the 14 sampling days. (See tables 4.1.2A and 4.1.2B for results and figure 3.1.1 for location). Drift point benzene values ranged between <1 ppm and 160 ppm. (The highest value recorded was from a sample obtained from a depth of 6 ft.) The range of values obtained in the drift point area may be in part controlled by the inability, to obtain samples from the same depth along with the time and spacial differences that could naturally occur. Depth achieved for any sampling point was controlled by local lithology. 15 'V! i I- .-• .. ..... 0685 Values reported in tables 4.1.1 and 5.0.1 are the calculated values without subtracting background and/or drift point values. The soil vapor screening survey identified three areas of measurable BTEX vapor concentrations: o Area 1 - Service station property and area south of property. Benzene vapor concentrations ranged from ND to 1,675 ppm. o Area 2 - West and southwest of service station. Benzene vapor concentrations ranged from ND to 128 ppm. o Area 3 - North and east of the service station. Benzene vapor concentrations ranged from ND to 2.5 ppm. Figure 4.1.3 presents a distribution map of benzene, toluene and xylenes soil vapor results found during this study. Due to unavailability of a gaseous standard for E-benzene, no values for this component are reported in this study. Contour maps of soil vapor concentrations for total BTEX, benzene, toluene and xylenes are presented in figures 4.1.4, 4.1.5, 4.1.6 and 4.1.7 respectively. The contour maps have been derived from values obtained from the soil gas survey and do not constitute concentrations of hydrocarbons in the soil or groundwater of the area in question. 16 Tll'T O03 0686 TABLE 4.1.1. HIGHEST CONCENTRATIONS OF AROMATIC HYDROCARBON VAPORS FOUND IN SOILS GAS SAMPLES, ESSO TUTU AREA (PPM) LOCATION " DATE DEPTH BENZENE TOLUENE XYLENE [-1 1-2 1-3 1-4 1-5 1-7 1-3 1-8 1-3 I -10 1-12 1-13 1-14 1-15 1-16 1-17 1-13 1-19 1-20 1-21 1-22 APRIL/20 APRIL/06 APRIL/06 APRIL/22 . APRIL/20 APRIL/07 APRIL/07 APRIL/07 APRIL/11 APRIL/11 APRIL/07 APRIL/07 APRIL/11 APRIL/ 15 APRIL/23 APRIL/22 APRIL/ 12 APRIL/11 APRIL/16 APRIL/12 APRIL/12 3'10" 2'6" 1'6" . 3'0" 3'0" 2'4" 4'0" 8'0" 4'8" 2 '3" 3'6" 4'0" 3'6" 3'6" 2'3" 4'0" 2'10" 7'5" 2'4" 4'6" 3'0" ND ND ND 24.68 0.223 40.55 1137.593 1268.772 977.536 128.630 2. 353 ND 70.6 ND 0.102 1675.18 ND ND 0.116 0.004 135.8 0.722 ND ND ND 3.277 ND ND ND 296.955 44. 196 ND ND 11.32 0.249 0.391 80.45 U.011 ND 0.522 ND 10.56 ND ND ND 3.295 0.011 17.81 29.1 445. 1 54.553 10.S76 349. 1 ND ND 0.098 ND 83.92 ' ND ND 3.922 ND ND TUT 17 1-23 1-24 1-25 1-28 1-29 II-l II-2 II-3 II-4 II-5 II-6 1 1 -7 II-8 II-9 11-10 11-11 11-12 11-13 11-14 11-15 11-16 11-17 11-18 11-19 APRIL/12 APRIL/ 14 APRIL/20 APRIL/13 • - APRIL/13 APRIL/16 APRIL/16 APRIL/16 APRIL/18 APRIL/19 APRIL/19 APRIL/19 APRIL/ 19 APRIL/19 APRIL/20 APRIL/21 APRIL/21 APRIL/ 21 APRIL/21 APRIL/21 APRIL/22 APRIL/22 APRIL/22 APRIL/23 4'0" 2'8" 3'0" 4 '6" 4'8" I'll" 2'2" 2 '3" 4'0" 1'8" 2'4" 3'9" 5'6" 3'0" 2'0" 2'4" 2'9" 3'0" 3'0" 3'0" 3'0" 2'6" 2'2" 2'9" 6.11 0.042 ND 0.057 ME 0.763 2.598 ND ND 0.009 0.052 0 . 024 ND 0.030 0.235 ND ND 0.286 0.081 O.D13 0.050 0.109 ND 0.016 ND 0.418 0.173 0.015 ME 0.012 0. 174 0. 144 0.135 1.86 2.75 1.64 0.745 0.683 5.847 15.03 0 .018 3.987 1.79 0.014 0.833 0. 131 1.21 1.184 ND 1.37 0.003 0.465 ME 0.021 0. 199 0.418 0. 132 0 .001 3.924 ND 0.003 ND 0.012 1 .30 0.067 0.005 0.066 0.056 0.481 0.033 ND • 0.925 ME-Masking Effect ND-Not Detected 18 Table 4.1.2 A VALUES SHOWING HIGHEST CONCENTRATION OF AROMATIC HYDROCARBON VAPORS, ESSO TUTU AREA (PPM) M-P-XYLENE 0-XYLENE ND ND ND ND ND ND ND ND ND ND ND 5.880 0.984 0.330 ME MASKING EFFECT ND NOT DETECTED LOCATION D.P.1 D.P.2 D.P.3 D.P.4 D.^P.5 D.P.6 D.P.7 DATE 4/6/88 4/7/88 4/8/88 4/11/88 4/12/88 4/13/88 4/14/88 DEPTH 8'0" 6'0" V 3 '6" 6'8" 6'0" 7'0" 6'3.5" BENZENE ND 160.679 ND ND ME ND ND TOLUENE ND ND . ND ND ND 0.660 0.964 19 TUT 003 Table 4.1.2 B VALUES SHOWING HIGHEST CONCENTRATION OF CHLORINATED HYDROCARBON VAPORS, ESSO TUTU AREA (PPM) LOCATION D. D. D. D. D. D. D. P. P. P. P. P. P. P. 1 2 3 4 5 6 7 DATE 4/6/88 4/7/88 4/8/88 4/11/88 4/12/88 4/13/88 4/14/88 DEPTH 8 6 3 6 6 7 6 '0" • Q.I '6" •8" '0" •0" '3.5" DCE ND ND ND ND ND- ND 22.16 TCE ND ND ND ND ND ND 0.104 PCE ND ND ND ND 3.064 ND 0.1 96 ND NOT DETECTED 20 TUi 003 0690 i ! E • : • ! ! H I-T3O OX;; nmC/) HI So X m m s ii s" is 2 III i! : In / .«,:. »'-• &• *3 U bJ ' e = = iJ;.* * ir , i • •«* i|!:.; >||i _j •s- 1 h : -T^I^/ !:>i ES " * 4.2 AREA. 1 - ETSS facility and area south of the property. The survey results show hydrocarbon vapor concentrations ranges f r o m ND to 1 , 6 7 5 ppm of b e n z e n e . The h i g h e s t concentrations were found in the south and central portion of the service station. Due to the variable depth to bedrock at the site, sampling at two different depths at the same location was not always possible. The service station contains fill material surrounded by retaining walls. The retaining walls comprise the facility boundaries. Land surface elevation measurements (see figure 4.2.1) indicate an average height differential of approximately 5 ft. between the service station underground storage tanks area and the south portion of the shopping center parking lot adjacent to the facility. Two sample stations 1-2 and 1-3 immediately south of the facility tank field showed nondetectable levels of aromatic hydrocarbon vapors. However, at sample station 1-4 located south of the western section of the ETSS property, the benzene vapor concentration was 24 ppm. Sample stations further south show significantly reduced levels of benzene vapor concentrations (see figure 4.1.3 for values). 22 I LI I OO3 0692 V vwr^^^v^;;^^ v". . \ • ,v'•";• \ FIGURE 4 . 1 . 4 TOTAL BTX SOIL VAPOR CONCENTRATIONS (PPM) PREPARED FOR BELGODERE AND ASSOCIATES, INC LOCATION : FOUR WIND PLAZA SHOPPING CENTER STATE ROAD NO 38 ST THOMAS, US. VIRGIN ISLAND _najM tr ivf ALVAMEZ - OIAZ ASIOCIATCS "••" "' •' ' • ...,' &(/-",? '/f/s UMI*IM« Pt«i 0«tl*l I I FIGURE 4 . 1 . 5 BENZENE SOIL VAPOR CONCENTRATIONS (PPM) PREPARED FOR : BELGODERE AND ASSOCIATES, INC LOCATION : FOUR WIND PLAZA SHOPPING CENTER STATE ROAD NO 38 ST THOMAS, US. VIRGIN ISLAND \ \ iu..ij_.cr.T,,,c..L " " " — •«.! A L V A R C Z - D I A Z A S S O C I A T E i.n, u,,.., ',,.: . ,,, ,-xJ*5-; M*it«llfl« DIM 0««l*i 1 1 L • _ . . . : •»-"«-^j:'-—•__ __ u FIGURE 4 . 1 . 6 TOLUENE SOIL VAPOR CONCENTRATIONS (PPM) PREPARTO FOR BrLGODEHF AND ASSOCIATES, INC LOCATION : FOUR WIND PLAZA SHOPPING CENTER \ \ \ \ STATE ROAD NO 38 ST THOMAS, US. VIRGIN ISLAND \ \ 7?)J \ "—"--—••- .....,»..,..,.,., ...:-fx±:.: ONVTSI NI9HIA sn 'svwoHi is ec ON OVOH 3ivas H3iN3D ONUdOHS VZVHd ONIM dOOJ DNI S31VIOOSSV ONV 3H3Q00139 NOIitfDOT UOJ 03>JVd3dd NOI1VA313 -'"-''•"-'••-•--"iL. ^ / , •••»««,„ ~::»k ,' T =**,. * •:• ! I:. """ ;. x - j |i V--. •»• X •^' ,.;;- (( j.^ 'i ^ ' I;:,"'.".'' , jj.J'j ^.v. <«*t» 4.3 AREA 2 - Area west and southwest of ETSS facility. Concentrations of benzene hydrocarbon vapors found in the area west and southwest of the ETSS facility range from ND to 128 ppm. (see figure 4.1.3). The highest benzene concentration in this area, 128 ppm, was found at station 1-10. This station is near a pipeline which once connected the ETSS facility oil/water separator to the Four Winds parking lot storm water drainage. This pipeline was in service for a relative short time before it was disconnected and capped. 4.4 AREA 3 - North and east of ETSS facility. A third area of measurable aromatic hydrocarbon vapor concentrations ND to 2.5 ppm of benzene, was found to extend to the survey boundaries, 400 ft. to the north and 83 ft. to the east of the ETSS facility. It is not possible to ascertain the sources of hydrocarbon vapors found in the area from this soil vapor survey. A more direct method such as borings, monitoring well installations, and sampling and analyses will have to be employed to refine the data base. 28 TU 5.0 CHLORINATED HYDROCARBON Table 5.0.1 presents the results of chlorinated hydrocarbon (TCE, PCE & DCE) analyses for each soil vapor sample collected during the. survey. Copies of all chromatograms and daily calibration curves are presented in the separate supplement e n t i t l e d : "Photocopies of Original Gas Chromatograms and Calibration Curves". Chlorinated hydrocarbons, although not typically found in motor fuel, were analyzed in the soil vapor samples at the request of DPNR-EPA. This request was made because chlorinated hydrocarbons were found in water supply wells in the Tutu area. The survey results show that the highest chlorinated hydrocarbon (DCE, PCE & TCE) concentrations ranging from ND to 189 ppm were obtained in area 2. Total chlorinated hydrocarbon vapor samples from stations 1-4 and 11-11 in Area 2 yield values of 78 and 189 ppm, respectively (see figure 5.0.2). In Area 1, seven samples were analyzed for chlorinated hydrocarbon vapors. The values range from ND to a high of 16 ppm of total chlorinated hydrocarbon vapors at Station 1-23 located on the northwest corner of the ETSS facility. At Station 1-17 chlorinated hydrocarbon vapors were detected but due to the high concentrations of aromatic vapors, quantification of chlorinated vapors was not possible. In Area 3, the highest concentration of total chlorinated hydrocarbon vapors, 13 ppm, was found at Station II-8 located on the edge of the survey northwest boundary. Concentrations of chlorinated hydrocarbon vapors in 29 Area 3 decrease toward the southern portion of this area. This is evident by values obtained from samples at Stations 11-4, 1-28 and 11-8. Based on the limited scope of this screening survey, and the geological condition found in the area, it is impossible to ascertain the source(s) of chlorinated hydrocarbon compounds. 30 TABLE 5.0.1 HIGHEST CONCENTRATIONS OF CHLORINATED HYDROCARBON VAPORS FOUND IN SOIL GAS SAMPLES, ESSO TUTU AREA (PPM) LOCATION 1-1 1-4 1-5 1-9 1-10 1-14 1-16 1-17 1-18 1-19 1-20 1-21 1-22 • 1-23 1-24 1-25 1-28 1-29 . . DATE APRIL/20 APRIL/22 APRIL/20 APRIL/11 APRIL/11 APRIL/11 APRIL/23 APRIL/22 APRIL/12 APRIL/11 APRIL/16 APRIL/12 APRIL/12 APRIL/12 APRIL/14 APRIL/28 APRIL/13 APRIL/13 DCE ND 186.87 0.2538 ND ND 3.098 0.569 ME. ND 0.014 ND ND ND ND 0.043 0.007 0.908 ND TCE 0. 179 ND 0.3417 ND ND ND ND ME ND ND ND ND ND 6.196 0.022 0.152 0.548 ND PCE ND 2.598 1.552 ND 13.70 5.83 ND ME 0.370 2.08 ND 2.98 ND 15.596 0.045 0.295 3.346 0.274 TOTAL 0.179 189.468 2.148 ND 13.70 8.928 0.569 ME 0.370 2.094 ND 2.98 ND 21.792 0.110 0.454 4.802 0.274 ,v?oi oC0 31 LOCATION II-l II-2 I I -3 II-4 II-5 II-6 I 1-7 I I -8 I 1-9 11-10 I 1-11 11-12 I 1-13 I 1-14 I 1-15 I 1-16 11-17 . I 1-18 11-19 ND-NOT ME-MASK DATE APRIL/16 ' APRIL/16 -APRIL/16 APRIL/18 APRIL/19 APRIL/19 APRIL/19 APRIL/19 APRIL/19 APRIL/28 APRIL/21 APRIL/21 APRIL/21 APRIL/21 APRIL/21 APRIL/22 APRIL/22 APRIL/22 APRIL/23 DETECTED ING EFFECT DCE 0.180 0.376 0.165 1.465 ND 0.028 0.065 O.870 0.022 1 .077 ND 0.043 ND O.361 0.332 O.O44 ND ND ND TCE ND ND 0.470 1.128 0.008 0.087 0.814 1 .350 0.084 O.964 73.47 ND ND ND ND 0.135 0.043 1O.88 ND PCE 0.102 0.358 1 .366 5.243 0.058 ND ND 11 .471 2.02 ND 5.24 ND ND 1.866 1.866 0.649 0.030 5.80 ND TOTAL 0.282 0.734 2.001 7.836 0.066 0.115 0.879 13.691 2. 126 2.041 7S.71 0.043 ND 2.227 2. 198 0.828 0.073 16.68 ND 32 6.0 Reconenda t ions The results of the soil vapor survey have indicated that detectable levels of both aromatic and chlorinated hydrocarbon vapors are present in the subsurface. However, it was not possible to ascertain the sources of these vapors, nor the actual concentrations that may be present as dissolved constituents in the local groundwater. To refine the existing data base, a more direct methodology of sampling and analyses must be employed. The f o l l o w i n g r e c o m m e n d a t i o n s are s u b m i t t e d for your consideration to achieve the desired results. A subsurface investigation is recommended to be undertaken consisting of drilling, well installation, and soil and water sample collection and analyses. The actual boring locations will be based on field conditions and site accessibility. Borings should be completed as monitoring wells to collect water level elevation data, and water samples for chemical analyses. During the drilling, the soil cuttings should be scanned with a portable photo-ionization detection (PID) meter to determine the concentration of volatile organic vapors. The PID readings may provide some indications of preferred zones of hydrocarbon movement. At the completion of the well installation program, the top of the casings should be surveyed to a common d a t u m . Additionally, the elevations of the nearby existing water supply 34 wells should be surveyed. Water level elevations will be measured and the general direction of horizontal groundwater flow can be established. The proposed new wells, and the nearby existing water supply wells should be sampled, and the water analyzed for selected dissolved constituents. To aid in the interpretation of the data, and assess the suitability of samples collected from the water supply wells with the use of the existing pumping equipment, as much information as possible should be collected and reviewed. Data such as: construction details, lithologic logs, pump setting, pumping rates, water-level measurements, and water-sample analyses should be collected and reviewed. 35 TUT GO3 O7O4 APPENDIX I OO3 0705 Second Revision Jan. 11, 1988 ESSO TUTU SERVICE STATION SOIL VAPOR INVESTIGATION PLAN Prepared for: Department of P l a n n i n g & Natural Resources, USVI, Environmental Protection Agency - Region II, N.Y December 28, 1987 Submitted by Esso Standard Oil S.A. Ltd Carlos M. Belgodere, Belgodere & Associates Inc. Project Coordinator. Ana- Gloria Ramos, P.E., ESSO Standard Oil SA LTD. Project Manager TABLE OF CONTENTS l.O Introduction.............................................. 1 1.1 Background........................................... 1 1.2 Hydrogeologic Setting................................ 2 1.3 Purpose and Methodology of Soil Vapor Investigation.. 3 2.0 Statement of Work......................................... 6 3.O Technical Approach........................................ 7 3.1 Task Ol Site History................................. 9 3.2 Task O2 Work Plan Development........................11 3.3 Task O3 Management and Coordination..................11 3.4 Task O4 Preliminary Site Investigation...............12 3.5 Task OS Preparation of QA/QC Plan....................13 3.6 Task O6 Soil Bas Sampling and Analysis...............13 3.7 Task O7 Data Analysis and Interpretation............. 19 3.8 Task O8 Preparation of Technical Report..............19 3.9 Task O9 Quality Assurance and Quality Control........20 4.O Performance Schedule and Schedule of Deliverables.........20 LIST OF FIGURES Figure 1.3.1 Illustration Showing Subsurface Vapor and Hydrocarbons Resulting from a Product Release. 4 Figure 3.6.1 Soil Vapor Extraction Procedure...............15 Figure 3.6.2 (a) Phase I Soil Bas Sampling Point Locations.....17 TUT 003 Figure 3.6.2 (b) Phase II & III Soil Vapor Sampling Points Location......................................18 Figure 4.0.1 Site Investigation Schedule...................21 Figure 4.O.2 Deliverable Schedule..........................22 LIST OF APPENDICES Appendix A Resumes of Staff for Esso Service Station Soil Vapor Study Survey ii TUT 003 0708 1.0 Description of Work 1.1 Background A number of water w e l l s have been shut down by the Depart- ment of P l a n n i n g and Natural Resources of the USVI (DPNR) and the Environmental Protection Agency Region II, New York (EPA) as a result of reported ground water contamination in the Tutu area of St. Thomas, USVI. DPNR/EPA b e l i e v e that among the p o s s i b l e sources of hydrocarbon contamination found in the ground water may be one or more of the various gasoline service stations which operate or had operated in the Tutu area. Esso Standard Oil S. A. Ltd. (ESSO) is the owner of the gasoline service station located in the Four Winds Shopping Center at the Tutu Area of St. Thomas. In c o n s i d e r a t i o n thereof, DPNR has ordered ESSO to s u b m i t an investigation plan to assess the potential seepage of product into the underlying soil of the above referred Service Station. ESSO has requested Belgodere & Associates Inc. (BAI) to perform the a b o v e m e n t i o n e d i n v e s t i g a t i o n ordered by DPNR. Pursuant to DPNR Administrative Order of September 17, 1987, the p l a n c o n t a i n e d h e r e i n h a s been d e v e l o p e d t o e f f e c t i v e l y characterize the contaminants, if any, at the soils beneath the Service Station. The study w i l l encompass an assessment of the possibility of motor fuel releases from underground storage tanks/pipelines and p o t e n t i a l m i g r a t i o n pathways at the Esso Service Station by performing a soil vapor survey. If as a result of the soil vapor investigation it is determined that the Esso Service Station is not the source nor has contributed to the contamination of local TUT CO3 0709 aquifer, adequate releases will be sought by Esso Standard Oil S.A. Ltd. ESSO, and BAI Representatives have met with ERA Project Manager, Ms. Caroline Kwan, DPNR Representative, Ms. Francine Lang, and the Project O f f i c e r at Camp, Dresser & Mckee Federal Programs Corporation (CDM-FPC) Mr. Scott B. Graber. DPNR, E P A , and C D M - F P C h a v e d i s c u s s e d the p r i n c i p l e s for the t e c h n i c a l approach and work schedule presented in this Work Plan. It is our u n d e r s t a n d i n g that all p a r t i e s are in agreement w i t h the concepts and schedule presented herein. 1.2 Hydrogeologic Setting The Esso Service Station is located in St. Thomas U.S.V.I., on the West Side of Rd #38 in the Tutu area, at the Four Winds Shopping Center Parking Lot. According to information obtained from "Soil Survey V i r g i n Islands of the US, 1970 Soil Conservation Service Report", issued in August 1970, the area is described as a network of terraces and a l l u v i a l fans sloping gently to moderately toward the south. Soil deposits consist of stratified sands, gravels and clays with a permeability of 0.20 to 0.63 in./hr. Soil strata thickness around site location varies from bare rock on slope side of h i l l s to over 20 ft. on a l l u v i a l deposits. Based on topographic and structural information obtained from "Geology of St. Thomas and St. John, U.S. Virgin Islands" by Thomas W. Donnelly (NSF, G-114407) the local water table should generally slope to the south. Direction of local ground water flow is controlled by volcanic bedrock fractures underlying the si te area soiIs . TUT 003 0j'71.0 B a s e d o n d i s c u s s i o n w i t h l o c a l w a t e r w e l l d r i l l e r s ( P o l y C a r i b e ) depth, of ground w a t e r at the Four W i n d s S h o p p i n g Center w e l l , located 25 ft. north of the S e r v i c e Station and the Tillett Water W e l l , located 250 ft. north east, is reported to be b e t w e e n 15 and 20 ft. d u r i n g the r a i n y s e a s o n s w h e r e water table is high and pumping of commercial and residential w a t e r w e l l s i s l o w . T h e l o c a l a q u i f e r w a t e r t a b l e h a s been p r e v i o u s l y o b s e r v e d beyond 80 ft. as a result of high w a t e r e x t r a c t i o n during extended drought periods. 1.3 Purpose and Methodology of Soil Vapor Survey. T h e p u r p o s e o f t h e p r o p o s e d s o i l v a p o r s u r v e y i s t o d e t e r m i n e w h e t h e r there has been a leak or a s p i l l from the S e r v i c e Station underground storage tanks and/or pipelines that may have contributed to the local aquifer contamination a n d , if leaks and/or s p i l l s from the Service Station are identified, to determine their areal extent. In theory, when an underground motor fuel tank or pipeline e x p e r i e n c e m e c h a n i c a l i n t e g r i t y f a i l u r e a n d r e l e a s e o c c u r s , hydrocarbons a r e e x p e c t e d t o m o v e d o w n w a r d i n t h e direction of the water table and then carried in the upper part of the shallowest aquifer 1n the direction of ground water flow, therefore, contaminating soils along its pathway due to capillary action of soil matrix (figure 1.3.1). Soils containing motor fuel c o m p o n e n t s w i l l y i e l d w h e n a n a l y z e d high v a l u e s o f t o t a l hydrocarbons, benzene, toluene, ethyl-benzene and xylene when soil vapor is extracted from soils stratas underneath and around o TUT OO3 0711 s u s p e c t e d p o i n t s o u r c e s . R e l a t i v e l y h i g h h y d r o c a r b o n concentration in soil vapor from the zone above the hydrocarbon plume w i l l often a l l o w for efficient mapping of plume origin and e x t e n d by s y s t e m a t i c a l l y o b t a i n i n g soil v a p o r samples and a n a l y z i n g them for hydrocarbons content. The p r o p o s e d s o i l v a p o r e x t r a c t i o n and a n a l y s i s to be performed in the Esso S e r v i c e Station area w i l l : o Detect the p r e s e n c e , if a n y , of total h y d r o c a r b o n s B e n z e n e , T o l u e n e , E t h y l - B e n z e n e , X y l e n e , T r i c h l o r o e t h y l e n e , T e t r a c h l o r o e t h y l e n e , a n d Dichloroethylene contamination in soils. o If contamination in soils is present, it will identify and define its nature and extent. S o i l v a p o r c o n t a m i n a n t i n v e s t i g a t i o n r e f e r s to a m e t h o d r e v i v e d by Thomas M. Spittler ( E P A Region I Laboratory) from the Oil and Gas Exploration Industry for investigating underground contamination by means of detecting organic vapors. The method i n v o l v e s pumping a small amount of soil vapor out of the ground through a hollow probe driven to a desired depth and analyzing the vapor for the presence of volatile contaminants. The soil vapor a n a l y s i s is performed in the field so that samples do not have to be packed or shipped also, analytical results are a v a i l a - ble immediately and can be used to help direct the investigation. The investigation is usually carried out by analyzing soil vapors in 50'-100' center trancets across the suspected contaminated a r e a u n t i l b o u n d a r i e s a r e w e l l d e f i n e d . T h e S o i l V a p o r Investigation Plan has been prepared in consonance with "Spittler M e t h o d " . P l e a s e refer to s e c t i o n 2.3 of the Q A / Q C P l a n for description of the Sampling Network Design and Rationale. 2.0 Statement of Work In order to determine the range, and spatial distribution of motor fuel that may be present in the soil at the Esso Tutu Service Station, ESSO will implement a two-phase approach which includes the following: Phase ]_ The first phase w i l l consist of s o i l vapor s a m p l i n g and analysis on a grid encompassing the Esso Service Station property to determine the presence, if any, of motor fuel contamination in the underlying soils. An extension of Phase I sampling grid w i l l be carried out beyond the Esso Service Station boundaries to determine, if any, the nature of the hydrocarbon plume. Phase I_I^ If s o i l c o n t a m i n a t i o n is found to have orginated at the Service Station, a further extension of the sampling grid w i l l be c a r r i e d o u t t o d e f i n e t h e a r e a l e x t e n t o f m o t o r f u e l contamination plume in soils above ground water. The soil vapor sampling program w i l l be terminated at the end of Phase I if it is determined that there is no evidence of motor fuel at the soils underneath the Service Station, or at the end of Phase II if it is determined that motor fuel contamination found on site i n m i g r a t e d from other sources outside the Esso Service Station property. The w o r k w h i c h E S S O p r o p o s e s to p e r f o r m is d e s c r i b e d in Section 3 of this Work Plan. The results of Phase I will trigger and influence the need for the other phases of this i n v e s t i g a t i o n . 3.0 Technical Approach The technical approach for this project has been developed w i t h s i g n i f i c a n t input from E P A a n d C D M - F P C a n d v a r i o u s s i t e v i s i t s p e r f o r m e d by E S S O and BAI R e p r e s e n t a t i v e s during the September-December 1987 period. The proposed study is divided into v a r i o u s t a s k s i n order t o p r o v i d e c h e c k p o i n t s a t w h i c h p r o g r e s s a n d f i n d i n g s w i l l b e e x a m i n e d , t h e r e f o r e , a l l o w i n g f l e x i b i l i t y f o r f i e l d d e c i s i o n s a s t o n e c e s s i t y f o r implementation of subsequent task phases. The t e c h n i c a l a p p r o a c h h a s been d i v i d e d into nine t a s k s . Through these t a s k s a Work Plan has been developed to conduct a soil vapor sampling grid. Soil vapor samples will be analyzed on site for the f o l l o w i n g parameters: o Total Hydrocarbons o Benzene o Toluene o Ethyl-benzene o Xy lene o Trichloroethylene o Tetrachloroethylene o Dichloroethylene TUr °03 0714 The three chlorinated hydrocarbon compounds, although not t y p i c a l l y found on motor fuels, w i l l be analyzed f o l l o w i n g suggestions from DPNR and ERA. Based on results from previous phases of the program, further soil vapor samples and analysis for the same parameters may be conducted as needed. A f i n a l report w i l l be prepared describing and i l l u s t r a t i n g the results of the study. The t a s k s to be p e r f o r m e d u n d e r the Work P l a n do not e n c o m p a s s p e r m i t r e q u i r e m e n t s u n d e r f e d e r a l a n d l o c a l environmental laws and regulations. There are no requirements under the Comprehensive Environmental Response, Compensation and L i a b i l i t y Act (CERCLA), the Resource Conservation and Recovery Act (RCRA), or any other environmental law o regulation, either federal or local, a p p l i c a b l e to the endeavors covered under the Work Plan. Occupational Safety and Health Standards found in 29 CFR 1910 are a p p l i c a b l e to this project. The Health and Safety Plan submitted herewith addresses the minimum safety procedures that w i l l be followed during the performance of all the tasks involved TUT O03 O71 in this Work Plan. The nine tasks are presented below: Task 01 Site History (completed) Task 02 Work Plan Development (completed) Task 03 Management Coordination (on going) Task 04 Preliminary Site Investigation (completed) Task 05 Quality Assurance Project Plan Preparation (completed) Task 06 Soil Vapor Sampling and Analysis Task 07 Data A n a l y s i s and Interpretation T a s k 08 Preparation of Illustrations and Technical Report Task 09 Quality Assurance/Quality Control To succesfully carry out this Work Plan within the estimated scheduled time frame, the Esso Project Manager, the BAI Project O f f i c e r , and DPNR/EPA designated Field R e p r e s e n t a t i v e s w i l l maintain the necessary communication to assure that efforts are c o o r d i n a t e d and each t a s k is c o m p l e t e d a c c o r d i n g to the W o r k Plan. Any necessary field changes or corrections in strategies w i l l b e e x a m i n e d c a r e f u l l y , a n d w i l l b e d o c u m e n t e d a n d c o o r d i n a t e d w i t h E S S O a n d a p p r o v e d b y D P N R / E P A F i e l d Representatives.. 3.1 Task 01 Site History The Esso Service Station located at the parking lot of the Four Winds Shopping Center, Road 38 in the Tutu neighborhood of S t . T h o m a s , U.S. V i r g i n I s l a n d s , initiated o p e r a t i o n s during 1970. The Service Station is equipped with two (2) underground fuel storage tanks of 6,000 gallon each. The Service Station, as 9 TUT 003 071& well as the necessary equipment and appurtenances for its opera- tion, such as the underground tanks and the gasoline pumps, are owned by Esso Standard Oil S.A. Limited, a Bahama corporation organized under the laws of Bahamas. Mr. Robert Duns, the Service Station first dealer, operated the station from 1970 through 1971, when Mr. Daniel Bayard took over its operation as Esso's new dealer and lessee. Daniel D. Bayard, Jr., the service station current dealer, assumed f u l l management responsibility of the Esso Service Station in March 1976 when his father, the previous dealer, went into retirement. Of the maintenance activities that have been conducted at the S e r v i c e S t a t i o n t h r o u g h o u t the years, o n l y two (2), the r e p l a c e m e n t of p i p i n g and an integrity test, may h a v e a bearing on the project. The 2 " p i p e s c o n n e c t i n g the d i s p e n s i n g u n i t s to the underground storage tanks were replaced from g a l v a n i z e d to fiberglass during 1985-1987. The replacement job was conducted by Mr. Eugenio de Arce, Esso's St. Thomas maintenance contractor. One of the two underground storage tanks was emptied and removed from service on July 27, 1987, after the results of a Petro-Tite tank test performed by Roque Schmidt Corp. caused Esso to question the structural integrity of the tank. The tank has remained empty ever since, pursuant to an order issued by the Department of Planning and Natural Resources of the U.S. V i r g i n Islands dated August 21, 1987. A physical examination of the tank has been unable to be performed pending DPNR authorization. 10 TUT 003 07 i: 3.2 Task 02 Work Plan Development The proposed Work Plan has been developed from: o Series of meetings between ESSO and BAI Representatives at the site to e v a l u a t e p h y s i c a l c o n d i t i o n that may restrain the technical approach. o Meetings and telephone conversations between ESSO, BAI, DPNR, EPA, and CDM-FPC personnel to establish the basic guidelines and objectives for the proposed study. The d e l i v e r a b l e for Task 01 is this Work Plan. The Work Plan may be adjusted as appropriate at the end of each phase pending on its outcome. 3.3 Task 03 Management and Coordination The BAI Project Officer will coordinate the technical execu- tion o f w o r k t a s k s d e s c r i b e d o n t h i s W o r k P l a n . T h e o v e r a l l Project Management will be performed by Esso Project Manager. The following is a list of a c t i v i t i e s to be performed under this t a s k : o P r o v i d e a s s u r a n c e that team s t a f f and r e s o u r c e s are provided so that each task is completed on schedule, o I n i t i a t e a p p r o v e d c h a n g e s t o t h e W o r k P l a n a s necessary, o e n s u r e that Quality Control and Q u a l i t y A s s u r a n c e measures are monitored and Implemented, o provide assurance that field personnel will adhere to Health and Safety Plan. 11 ..., 0718 TUT 00-> - ' 3.4 Task 04 Preliminary Site Investigation A preliminary site investigation has been performed during the months of September thru December 1987 to allow for optimiza- tion of resources during soil vapor extraction and testing opera- tion by identifying in advance the limitation imposed by local conditions, ie. topographic, geologic, construction, structures. This work plan is partially based on site specific requirements based on the results of the preliminary site investigation, as follows: o The area is mostly covered with concrete or asphalt and f i l l material above rocky soil which can l i m i t the soil vapor probe depth of penetration between 4 to 10 ft. o E s t a b l i s h m e n t of the s a m p l i n g g r i d is affected by numerous existing structures. Offset of grid points may be necessary to provide areal coverage. Sampling grid may be extended based on field judgment. o A c c e s s a u t h o r i z a t i o n from t h i r d p a r t i e s w i l l b e required to e s t a b l i s h s a m p l i n g points o u t s i d e the Service Station, if necessary. 12 TUT 003 0719 3.5 Task 05 Preparation of Quality Assurance/Quality Control Plan The attached QA/QC Plan Is a documentary record detailing the s a m p l i n g methodology, QA/QC procedures, data presentation and e v a l u a t i o n t e c h n i q u e s to be followed d u r i n g the f i e l d data collection, analysis and report preparation phases of this Work Plan. The QA/QC is based on the requirements outlined in the i n t e r i m g u i d e l i n e s and s p e c i f i c a t i o n s for p r e p a r i n g Q u a l i t y A s s u r a n c e Project P l a n s EPA-600/4-83-004, F e b r u a r y 1983 pub!ication. 3.6 Soil Vapor Sampling and Analysis The proposed soil vapor sampling and analysis program consists of a two-phase approach were the need for subsequent work w i l l be e s t a b l i s h e d by the results of phase I and f i e l d judgment. Soil vapor samples w i l l be collected by d r i v i n g a 5/8 inch diameter hollow stainless steel probe to the appropriate depth by h a n d or w i t h a p n e u m a t i c d r i v e r . After d e s i r e d d e p t h is achieved, 5 to 10 liters of soil vapor from around the shield p o i n t w i l l be extracted with the use of a 500cc/min battery operated vacuum pump attached to the probe with a vacuum gauge and a septum s a m p l i n g port via a teflon hose. A gas t i g h t syringe w i l l be inserted through the septum port to collect a 2 UL to 10 UL vapor sample for immediate on site analysis. TUT 003 O72O 13 D u r i n g all p h a s e s of w o r k , s o i l v a p o r s a m p l e s w i l l be analyzed using gas chromatographs owned and operated by BAI ( S e e s e c t i a n 6 and 7 of A Q / Q C P l a n ) . Two gas c h r o m a t o g r a p h s equipped with flame ionization detectors (FID) will be used to identify total h y d r o c a r b o n s and c h l o r i n a t e d h y d r o c a r b o n s . A n a l y s i s to be made at each sample point will consist of: o Total hydrocarbons o Benzene o Toluene o Ethyl-Benzene o Xy1ene o Trichloroethylene o Tetrachloroethylene o Dichloroethylene The second proposed phases of work to be conducted at the Esso Service Station area are as follows: Phase _!_ Phase I consists of soil vapor sampling on the Esso Service Station property. Sampling points w i l l be spaced in a grid 14 pattern approximately 50 ft centers (figures 3 . 6 . 2 a, b). Additionally, at least to sampling points will be located about 100 f e e t n o r t h - n o r t h e a s t ( h y d r o 1 o g i c a 1 l y u p g r a d i e n t ) of the S e r v i c e S t a t i o n s i t e t o s e r v e a s b a c k g r o u n d p o i n t s , w h e r e possible samples will be taken from depths of 4-5 feet and 8-10 feet at each point to determine whether there is a significant change in soil vapor values with depth. The second phase of this investigation will be conducted if t h e f o l l o w i n g c r i t e r i a s a r e m e t d u r i n g t h e f i r s t p h a s e . S i g n i f i c a n t a r o m a t i c h y d r o c a r b o n c o n c e n t r a t i o n s a r e found during Phase I, as follows: v a l u e s of hydrocarbons detected on the station property exceed those found in background locations by a factor of three or more. If required, Phase II will extend the grid pattern toward the east north-east on a 50, 100, or 200 ft. center as considered appropriate to determine if hydrocarbon contamination generated at the site or inmigrated from other sources. Phase H^ If data developed during Phase I and or Phase II indicate t h a t h y d r o c a r b o n c o n t a m i n a t i o n m a y h a v e been p o t e n t i a l l y TUT 003 0722 16 generated from the Esso Service Station, the soil vapor sampling grid w i l l be extended on 50 ft. centers toward the soutn south east and south south west as considered a p p r o p r i a t e based on field judgment. The grid w i l l be sampled and analyzed in the same manner as the grid established in Phase I, using the same d e p t h s b e l o w g r o u n d s u r f a c e . T h i s g r i d w i l l b e c o n t i n u e d southward, eastward and westward based on Field Judgment. 3.7 Task 07 Data Analysis and Interpretation D a t a a n a l y s i s a n d i n t e r p r e t a t i o n w i l l b e p e r f o r m e d simultaneously with the field work to allow changes in field work to properly orientate, extend or reduce the sampling grid based upon results of previously sampling and analysis. I n i t i a l data r e d u c t i o n a n d m a p p i n g o f s o i l v a p o r c o n c e n t r a t i o n w i l l b e performed at BAI, St.Thomas office. 3.8 Task 08 Preparations and Ilustrations of Technical Report After completion of the site investigation described under task 03 through 07, BAI w i l l prepare a final report discussing the results of the investigation. The final report w i l l include, as a minimum, a tabular presentation of the soil vapor analysis values encountered during the course of the investigation (ie. total hydrocarbons, benzene, toluene, ethyl-benzene, xylene, t r i c h l o r o e t h y 1 e n e and tetrachloroethylene) i l l u s t r a t i n g the spacial orientation of measured values. TUT 007; 19 Specific items to included in the report are: o Base map showing distribution of soil vapor s a m p l i n g poi nts; o contour maps of h y d r o c a r b o n v a l u e s to d e l i n e a t e hydrocarbon plumes and possible trajectory; o tables l i s t i n g all soil v a p o r hydrocarbon v a l u e s encountered during the course of this investigation; o maps showing relationship of hydrocarbons values in soil vapors to estimate ground water flow direction on local geology; o GC Chromatograms ; o conclusions and recommendations. 3.9 Task 09 Quality Assurance and Q u a l i t y Control QA Officer for this project, Eng. Omar Muniz has reviewed this work plan for QA requirements and w i l l maintain QA oversight t h r o u g h t h e d u r a t i o n o f t h i s project. B A I work o n t h i s assignment w i l l be conducted in accordance with project specific QA/QC which is being submitted with this Work Plan. 4.0 Performance Schedule and Schedule of Deliverable A site investigation plan schedule is shown in figure 4.0.1 and the deliverable date schedule 1s included on figure 4.0.2. The project schedule depends upon initiation of field work on January 26, 1988. A p p r o v a l of the Work Plan and Q u a l i t y Assurance, Quality Control Plan one week before that date w i l l be necessary to assure timely completion of the project. 20 Fi gure 4.0.2 DELIVERABLE SCHEDULE Proj ect D e l i v e r a b l e 1. Work Plan 2. QA/QC 3. Health & Safety Plan 4. Final Report I n i t i a l Text to DPNR/EPA 12/28/87 12/28/87 12/28/87 4/14/88 Recei pt of Technical Comments 1/25/88 1/25/88 1/25/88 N/A Fina 1 2/1/88 2/1/88 2/1/88 N/A 'TUT OO3 07 F1gure 4.0.1 SITE INVESTIGATION SCHEDULE Work Plan Development.................. Dec. 2 to Dec. 28, 1987 Review Approval ........................Jan. 20 to Feb. 1, 1988 Soil Vapor/Field Investigation.........Feb. 23 to Mar. 8, 1988 Data Evaluation........................Mar. 8 to Mar. 22, 1988 Final Report ...........................Mar. 22 to Apr. 5, 1988 TUT 003 0726 APPENDIX II OPERATIONAL PROCEDURES AUDIT SOIL VAPOR INVESTIGATION ESSO - TUTU SERVICE STATION ST. THOMAS, USVI INTRODUCTION The audit to the Soil Vapor Investigation conducted by Belgodere i Associates Inc. ( B A I ) , at the ESSO - TUTU Service Station was performed by Sharetech - Omar Munlz & Associates. The Quality Assurance (QA) Officer, Eng. Omar Munlz, was assisted by Mr. Jullo Rodrlguez and Mr. Jose G. Vila. Sharetech conducted a continuous field system and operational procedures check. Mr. Jose G. Vila was present during the complete project from April 5, 1988 to April 23, 1988. Observations and recommendations were brought to the attention and discussed with BAI personnel during this period. This report Is a summary of said information. PURPOSE OF THE AUDIT The audit was conducted to v e r i f y that the procedures described in the Work Plan and In the QA/QC Plan were being followed. The auditor was present for any consulting to the Project Officer, or any member from his staff In relation to necessary modifications based on the experience in the field. The main purpose Is to keep or improve the final work product. Tl!T OO3 07'i.B FIELD OBSERVATIONS Based on field judgments and/or mutually agreed decisions, some changes were necessary during the project. These were necessary due to field and specific site conditions. There were electrical voltage variations and intermittent power failures, which caused some unexpected delays. Additional field equipment was brought into the operation to solve this problem. Among these were an auxiliary power plant and electric current rectifier. One of the two Gas Chromatographs (CG) was equipped with a PID detector. At the end of the first week of the project, due to communication problems with CDM FPC, the amount of sample to be injected into the GC was increased. Upon increasing the sample injection the detector started to malfunction and to show no or very poor resolution. The peaks of concern did not appear. The most probable causes for these conditions are that the PID detectors were affected by humidity, electrical variations, as well as the increased sample injection. After the PID detector was rendered inoperative, its use was discontinued for the rest of the project. In order to check on the validity of the FID detector, standard samples were injected to verify the resolution. After few injections and the adjustments to the instrument conditions, all the parameters of concern were clearly recognized. The samples of the first week were qualitatively analyzed. The quantification of these samples was performed afterwards. TUT 003 The sampling procedures were followed as described in the plan with minor changes. The depths from which samples were collected were changed in those situations where subsurface conditions did not allow penetration to the target depth. COM FPC representatives suggested that the minimum depth for vapor sampling be established at two feet below surface. In addition, a minimum depth separation of two feet must be maintained between sample collection at the same station. This sampling procedure was mutually agreed. A total of sixty-two (62) samples were collected during the investigation. At the beginning of field activities and at the request of EPA and CDM FPC, the original sampling pump was replaced with a pump having an indicating flow device and a higher capacity. The new pump was calibrated before its use and checked again at the end of the project. Pump calibration did not vary more than one percent. Internal quality control checks such as field blanks, syringe blanks and equipment blanks were conducted during the project. Three point calibration samples were processed and plotted at a latter date. Although the work plan originally considered the .taking of duplicate samples at each sampling point, two independent samples were taken in sequence. The method of taking the samples did not allow for replicate samples because of the dynamic conditions of the source where samples were taken. TUT 003 0730 DEVIATIONS FROM WRITTEN PLAN QA/QC PLAN DEVIATION SECTION PAGE A. All samples were not field tested for 2.3 2 Total Hydrocarbons, Benzene, Toluene, Ethylbenzene, Xylene, Trichloroethylene, Tetrachloroethylene and Dichloroethylene. B. Other GC columns were used. 2.3 3 C. Samples were injected to the GC using the 4.0 7 same gas tight glass syringe in which samples were collected. D. During the first week of work one point 6.0 11 calibration checks were conducted. E. The Photo lonization Detector was eliminated 2.3 3 at the beginning of the investigation. F. Calibration checks did not necessarily 6.0 11 follow after each five samples sequence. G. The standard for 100 PPM of BTEX was not 8.2 13 available at the start of the investigation. RECOMMENDATIONS The results for each day of work should be reported to include the calibration curve with the respective chromatograms and the chromatograms of each of the samples. All the deviations mentioned before should be explained in the final report. It is highly recommended that the Project Manager include all the statistical analyses and criteria used for data validation and the use and limitations of the results obtained as applicable. TUT OO3 0731