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HomeMy WebLinkAboutMITIGATION t- " e California Regional Water Quality Control Board Central Valley Region Robert Schneider, Chair Alan C. Lloyd Ph.D SecrelnlJ} for Environmental Protection Fresno Branch Office Intemet Address: http://www.swrcb.ca.gov/-rwqcb5 1685 E Street, Fresno, Califomia 93706-2020 Phone (559) 445-5116' FAX (559) 445-5910 Arnold Schwarzenegger Governor 27 December 2004 RWQCB Case No. 5T15000619 _ Mr. Ki Chu Yi Mr, Fast Service Station 600 Brundage Lane - Bakersfield, California 93304 LC~ ,NVC-)\76A-nc.vJ UND GROUND STORAGE TANK RELEASE, MR. F1ST SERVICE STATION, 600 BR UlvDA GE LAN, AKERS FIELD, KERN COUNTY You submitted First Quarter 2004 Groundwater Monitoring Report, Second Quarter 2004 Groundwater Monitoring Report & Remediation Status Report (Monitoring Report) dated 15 August 2004 and received by our office on 15 November 2004. E2C Remediation, Bakersfield (E2C) prepared the report on your behalf Greatly increased gasoline constituent concentrations were detected in some off-site groundwater monitoring wells during the second quarter 2004 monitoring' event. Increased concentrations were also detected on-site in the source area. High concentrations were detected again during the se~ond quarter 2004 monitoring event and floating petroleum product was detected in one down gradient well. Your consultant did not inform us of these increases in a timely maImer and did not submit a separate report for the first quarter 2004 monitoring event. Your consultant's actions are unacceptable for our oversight. Based on the increased gasoline constituent concentrations and the periodic appearance of floating product, we conclude that a significant mass of residual gasoline remains in subsurface soils above or below the shallow water table, The on- and off-site remediation systems, as designed, appear to have removed extractable gasoline constituents. An active remediation system designed to remove the residual gasoline should be reinstalled, Prior to reinstallation, we request that - additional investigation be conducted to determine the distribution of the residual gasoline. Submit a work plan proposing the investigation, RepOli significant concentration increases in multiple monitoring wells and presence of floating product within five working days of discovery. Monitor depth to groundwater and floating product thickness on amonthly schedule and submit monthly status reports. Remove floating product after each monthly monitoring event. Continue quarterly groundwater monitoring, The third quarter 2004 monitoring report is overdue, Submit the fourth quarter monitoring report, We reiterate our notification that a work plan for investigation to determine the vertical extent of impacted groundwater is overdue, Submit infoTI11ation concerning floating product removal activities. We approve continued low-flow air sparging until an active remediation system is reinstalled. A summary of the Monitoring Report and our comments follow, California Environmental Protection Agency #D ~<:1 Recycled Paper · ". Mr. Ki Chu Yi - 2- 27 December 2004 .f Monitorin2 Report Summary E2C conducted the first and second quarter 2004 groundwater monitoring events on 26 Febmaryand 18 May 2004, respectively, Monitoring,wells MW~15S, MW-15D, MW-16, and MW-17D were dry during the first quarter event. MW-14, MW-15S, MW-15D, MW-16, MW-17S, and MW-17D were dry during the' second quarter event, Monitoring well MW -11 has been taken out of serVice and has been replaced by MW-11R, Floating petroleum product was not observed in the monitoring wells during the first quarter event, although sheen was noted in MW-12 and MW-13, Floating product was measured at 0,2 feet in MW -13 during the second qUaIier 2004 event. Depth-to-water in shallow monitoring wells MW-1 through MW-12 ranged from 46.46 to 56.98 feet below the top of the casings (below TOC) during the first quarter 2004 event. Depth-to-water in shallow well MW-13 and nearby deep monitoring well MW-14 was 58.18 and 69,60 feet below TOC, ~~~~~respecti-veIy..-Depth-t0-water-in downgFadient-shallow-wel-l-MW-+-7S-was-measured-at-62:û8-fèet"below TOC, Depth-to-water in deep well MW-18, which draws water from a deeper zone, was 115,04 feet below TOe. Groundwater elevation decreased an average of approximately 6 feet during the first quarter, compared to the 11 November 2003 monitoring event. Groundwater elevation in on-site monitoring wells MW -7 through MW -10 decreased by an average of 2.44 feet while groundwater elevation in off-site wells MW-IIR, MW-I2, MW-13, and MW-17S decreased by approximately 10 to 13 feet. Depth-to-water in shallow monitoring wells MW-1 through MW-12 ranged from 41.16 to 48.89 feet below the top of the casings (below TOC) during the second quarter 2004 event. Depth-to-water in shallow well MW-13 was 58,28 feet below TOe. Nearby deep well MW':14 was dry, Depth-to-water in deep well MW -18 was 116,08 feet below TOe. Groundwater elevation increased approximately 5 feet during the second quarter, compared to the 26 Febmary 2004 monitoring event. Groundwater elevation in on-site monitoring wells MW - 7 through MW -10 increased by approximately 3 to 5 feet compared to the 26 February 2004 event. Groundwater elevation in off-site wells MW-1lR and MW-I2 increased by 7,61 and 11.81 feet, respectively. Groundwater elevation measured in off-site monitoring well MW -13 decreased by 0.2 feet while nearby deep well MW-I4 was dry. Groundwater samples collected during the first and second quarter 2004 monitoring events were --- --ana:lyzed~'for-tota:l-petrolet}m=hyd;rocarbons-aso gàsohne-frPH-g)-by-EP A Method--80-1-5M,and benzene,----- - - . toluene, ethylbenzene, and xylenes (BTEX), and methyl tertiary butyl ether (MTBE), tertiary butyl alcohol (TBA), di-isopropyl ether (DIPE),. ethyl tertiary butyl ether (ETBE), and tertiary amyl methyl ether (TAME) by EP A Method 8260B, During the first quarter 2004, TPH-g was detected in MW-I, MW-3, MW-7, MW-8, MW-1IR, MW-13, and MW-]4 at concentrations fro111 249 to 60,154 micrograms per liter (~lg/L), TPH-g was also detected in deep well MW -18 at 617 µg/L. The highest TPH-g concentrations were detected in MW -1 (60,154 ~lg/L), MW-8 (50,006 ~lg/L) and MW-IIR (39,978 µg/L) , Benzene was detected at 2,795 ~Lg/L in MW- 13 but not in the other samples. Toluene, ethylbenzene, and xylenes were detected in MW-1, MW-7, MW-8, and MW-] IR through MW-14. MTBE was detected in MW-14 at 2 µg/L. TBA, DIPE, ETBE, and TAME were not detected, V:\UGT\Projecls\.JDW _liIes\2004 Correspondence\Cily of Bakers1ield Cases\Mr. Fast GW 12-04.doc My. Ki Chu Yi - 3 - 27 December 2004 During the second quarter 2004, TPH-g was detected in MW-l, MW-7, MW-8, MW-IIR, and MW-12 at concentrations from 31,340 to 211,473 micrograms per liter (µg/L), Analytes were not detected in deep well MW~18, The highest concentrations were detected in MW-12 (211,473 µg/L), MW-7.(96,846· µg/L), and MW-IIR (70,665 µg/L). Benzene was deteèted at 19 µglL in on-site well MW-l. Toluen·e, . ethylbenzene, and xylenes were detected in MW-l, MW-8, MW-I1R, and MW-12. MTBE, TBA, DIPE, ETBE, and TAME were not detected, E2C shut down of the on- and off-site soil vapor extraction (SVE) and air sparging (AS) remediation systems during April 2003, From 8 April 2003 to 9 March 2004,38,254 gallons of floating petroleum product and groundwater was removed from monitoring wells by vacuum truck. E2C will continue to remove floating product 'if present. E2C is currently enhancing microbial degradation of gasoline constituents by operating low-flow (1 to 2 standard cubic feet per minute) air sparging (AS) systems on- and off::si.te, >... ..._ ._, E2C recommends that quarterly groundwater monitoring continue, Groundwater samples should be analyzed for TPH-g, BTEX, and the fuel oxygenates. Low-flow air sparging should be continued on- and off-site, E2C recommends that free product and groundwater pumping be resumed in monitoring wells off-site on a regular schedule, E2C may recommend additional assessment and remediation based on their evaluation of groundwater monitoring and remediation data, Comments Groundwater monitoring data from the first and second quarters of 2004 indicate greatly increased gasoline constituent concentrations inthe off-site monitoring network (south of Brundage Lane), During the 18 May 2004 monitoring event, TPH-g concentrations ftom 70,665 to 211,473 µg/L and floating petroleum product characterized this area. Floating product was noted in off-site monitoring well MW- 13 at 0.2 feet thiclc Floating product was previously found in MW-13 during the 10 June 2003, 23 May and 19 February 2002, and 6 August 2001 monitoring events. TPH-g and BTEX concentrations in MW- 13 during the 27 Februàry 2004 monitoring event increased one to two orders of magnitude compared to the previous four groundwater monitoring events. Benzene, which has not been detected on- or off-site, was detected at 2,795 µg/L in MW-13 during the 27 February event. TPH-g and BTEX concentrations have also significantly increased in off-site monitoring wells MW -7, MW -12, Increased concentrations ofTPH-g 311êftoluène, ethý1benzeiî.e,- arid"xýleneš were also detected in oh-site monitoring wells positioned at or near the source area, At our request, E2C has submitted preliminary groundwater monitoring data for the third quarter 2004. Based on this preliminary data, the TPH-g and BTEX concentrations in the off-site monitoring network were greatly reduced compared to the second quarter, and are characterized by TPH-g concentrations from approximately 1,800 to 59,000 µg/L. The on-site and off-site soil vapor extraction and air sparging (SVEI AS) remediation systems, as designed, appear to have removed economically extractable gasoline constituents during relatively brief operation periods, The on-site SVE/AS system operated continuously from 4 April to 14 May 2002 and was operated intem1ittently ("cycled") due to low influent vapor concentrations, until 3 April 2003, The off-site SVE/AS system operated from 6 March to 9 April 2003, EiC has previously maintained that gasoline constituents were present in soil within a thin zone at or just above the water table and that this V:\UG1ìProjects\.lDW _fIIes\2004 Correspolldence\City of Bakersfield Cases\Mr. Fast GW 12-04.doc Mr. K.i Chu Yi - 4- 27 December 2004 f small mass was largely removed during the brief remediation system operation periods, We do not disagree with E2C's conceptual model for gasoline distribution, However, based on the fluctuating and high dissolved gasoline constituent concentrations in groundwater, and the periodic reappearance of floating product, we conclude that a si~ificant mass of gasoline remains in the vadose zOne or beneath the shallow water table, severely impacting groundwater quality, Overpurging of floating product by vacuum truck from 8 April 2003 to 9 March 2004 appears to have had a limited, temporary effect. At present, we believe that you should reinstall an active remediation system designed to remove the remaining gasoline constituent mass. However, the distribution of the residual mass is presently unknown, Prior to reinstallation of a remediation system, we request that you conduct additional investigation to locate and define the extent of the remaining gasoline mass on-site and off-site, Submit .~ _. .'~~ ___a work pJ.ªn forJ:h~iny.e$tigation by_17_.Eebruary-2005,-·" - ~...-"-~--.-...~~." .,,~ ...~_.- .-- .--. - - - By our letter dated 26 August 2003, we stated that we consider it necessary to further investigate potential contaminant flow pathways beneath the present shallow monitoring network. We requested that you submit a work plan addendum to install a deep monitoring network beneath the present shallow network. At least four deep monitoring wells screened to determine the vertical extent of impacted groundwater along the length of the known plume and a sentinel well south of State Highway 58 were to be proposed in a work plan addendum to be submitted by 30 October 2003, E2C has indicated that they wish to discuss or amend the scope of this investigation, By our letter dated 10 June 2004, we noted that the addendum was overdue and requested that E2C contact us by 15 July 2004 to discuss their concerns, As of the date of this letter, we have no record that they attempted to contact us. We reiterate that the work plan is overdue, lfthe work plan is not forthcoming, we will formally require submission under Section 13267 of the California Water Code. Your consultant failed to inform us of the increased gasoline constituent concentrations and floating petroleum product in a timely manner and has not submitted monitoring reports on a quarterly schedule, These oversights may have contributed to the spread of groundwater pollution and have certainly delayed our request for active remediation, Floating product and increased dissolved concentrations were discovered during the February and May 2004 monitoring events, E2C did not submit a __ gr:o~...1~c!w-,~J~r monitg~iq.g rep@Lsµ11}1l!.3!'!~!QKth§XeÞJJJªry _data_and_did.noLinform.us.oLthejncreased---.- - -- -~. concentrations, We were not notified ofthe increased concentrations or floating product until we received the Monitoring Report, which summarizes both monitoring events, Although the Monitoring Report was dated 15 August 2004, we did not receive it until 15 November 2004, We have also received other submissions from E2C approximately two to five months after the report date. Your consultant's actions are unacceptable for our project oversight. Your consultant is to inform us of any increases in gasoline constituent concentrations greater that one order of magnitude in multiple monitoring wells and of the presence of floating petroleum product within five working days of discovery, Continue quarterly groundwater monitoring. Analyze groundwater samples for TPH-g, BTEX, and the fuel oxygenates MTBE, TBA, DIPE, ETBE, and TAME. We also request that you monitor the depth to groundwater and floating product thiclmess in all monitoring wells on a monthly schedule and submit . this data in brief monthly status reports, Remove floating product discovered after each monthly monitoring event. V:\UGT\ProjeclsI.IDW _liles\2004 Correspondence\City of Bakcrs1íeld Cases\Mr. Fast GW 12-04.doc Mr. Ki Chu Yi - 5 - 27 December 2004 Submit the fourth quarter 2004 groundwater monitoring report by 1 February 2005, Submit monthly floating product status repOli by the 10th day of the next month. E2C provided waste manifests for fluids removed during overpurging 'events in the Monitoring Report. ' ' However, details concerning these events were not provided, We request that a schedule of the dates, approximate times, and volumes of removed fluids be submitted by 1 February 2005, We approve continued low-flow oxygen air sparging on- and off-site until an active remediation system is reinstalled, Please contact this office at least five days in advance of fieldwork, Should you have any questions regarding this matter, please contact me at (559) 445-5504. 8tJ~" JOHN D, WHITING Engineering Geologist R.G. No, 5951 cc: Ms, Barbara Rempel, UST Cleanup Fund, Sacramento "'" Mr. Howard Wines III, Bakersfield Fire Department, Bakersfie1ðv Mr. William Lawson, E2C Remediation, LLC, Bakersfield File: UST/Kern/Mr. Fast Service Station/600 Brundage Lane, Bakersfield/5Tl5000 V',\UG1\Projecls\IDW _!ìles\2004 Correspondence\City of Bakersfield Cases\Mr. Fast GW 12-04,doc