ARCHIVED REPORTS XR0001895 - Laserfiche WebLink

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s HYDRA • ENVIRONMENTAL TECHWOLOGIES,INC. • Mr P E Copple April 7, 2004 Page 2 In their November 4, 1999 letter, the San Joaquin County PHS/EHD requested a further investigation to determine the lateral and vertical extent of the petroleum contamination at the subject property HETI installed six DP borings throughout the subject property Grab ground water samples were obtained from each boring No detectable concentrations of TPH as gasoline, TPH as diesel, benzene, toluene, ethylbenzene and total xylenes (BTEX), or the five fuel oxygenates were found in the 46 soil samples and six grab ground water samples submitted for analysis HETI then installed three ground water monitoring wells to sample ground water and to determine ground water flow direction and gradient TPH as diesel was detected in all three ground water monitoring wells No detectable concentrations of TPH as gasoline, BTEX, the five fuel oxygenates, 1,2-dichloroethane (1,2-DCA), or 1,2-dibromoethane (EDB) were found in the ground water samples submitted for ;analysis In September 2000, HETI began quarterly ground water monitoring at the subject site During the first quarter of ground water monitoring, TPH as diesel was detected in MW-I and MW-3 No detectable concentration of TPH as diesel was found in MW-2 No detectable concentrations of TPH as gasoline, BTEX, the five fuel oxygenates, 1,2-DCA, or EDB were found in the ground water samples submitted for analysis During the August 2001 sampling round, MW-2 and MW-3 were dry and no samples were collected A sample was collected from MW-1, however, the laboratory's quality control failed to produce results within acceptable detection ranges All of the ground water monitoring wells were dry (MW-1 to MW-4) during the November 2001 sampling round PROPOSED PRASE II CONTAMINANT DELINEATION INVES'T'IGATION Protect Objectives Based on current information that you provided to us, HETI proposes to conduct an additional Phase II investigation to determine the extent of the petroleum contamination as required by the San Joaquin County PHS/EHD Task 1; Subsurface Soil and Ground Water Investigation HETI personnel will conduct an on site subsurface soil and grab ground water exploration near the former UST excavations Prior to any subsurface investigations, HETI will prepare a work plan and a health and safety (H&S) plan and obtain the required PHSIEHD permits The H&S plan will be prepared in accordance with U S Environmental Protection Agency (USEPA) 29CFRI910 120 and California GISO 5192 All on-site HETI and subcontractor personnel will be required to adhere to the H&S plan and to have had 29 CFR1910 120 training and its annual update The HETI project manager will have had the 29CFRI910 120 and California GISO 5192 eight-hour supervisors' course Copies of the work plan and H&S plan will be submitted to the San Joaquin County PHS/EHD for approval Soil boring locations will be marked prior to drilling Underground Service Alert (USA) will be notified at least 48 hours prior to any subsurface investigation The subsurface investigation will be under the supervision of a California Registered Geologist (RG) • Soil samples will be obtained from six DP borings using a Stratprobe DP drilling rig Soil samples will be collected at 5 0-foot intervals beginning at 10 feet bsg (the approximate bottom of the UST excavation) a