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1.INTRODUCTION <br /> pipeline was placed back in service by March 1986 (Figure 2). The release area is bounded to <br /> the north and west by Trapper Slough and to the east by Whiskey Slough Road and an <br /> agricultural field. The Site is collocated with the Arcady Oil Company (Arcady)Mud , <br /> Disposal Site,which was operated as a Class III disposal site for oil-drilling muds between <br /> April 1960 and May 1984 under Waste Discharge Requirements issued by the RWQCB. <br /> Hydrocarbon residuals from the February 1986 pipeline release are present in subsurface <br /> soils and groundwater at the Site. A comprehensive summary and analysis of historical site <br /> investigation and interim remediation activities addressing these hydrocarbons are <br /> presented in the Final Site Characterization Report(CH2M HILL,2002). A summary of these <br /> historical activities is provided below,followed by a summary of current site remediation <br /> activities and recent MRP history for the Site. <br /> 1.2.1 Site Investigation Activities <br /> SFPP completed significant investigation activities to characterize the subsurface physical <br /> characteristics, the nature and extent of hydrocarbon-affected media,and the fate-and- <br /> transport mechanisms at the Site. These investigations showed that dissolved-phase <br /> hydrocarbons and separate nonaqueous-phase hydrocarbons (NAPH)were present in the <br /> vicinity of the former SFPP pipeline and migrated southeast beneath Whiskey Slough Road. <br /> Beginning in 1987 after the spill and emergency response activities,numerous investigations <br /> were performed that have defined the horizontal and vertical extents of these hydrocarbons. <br /> These investigations included the following activities: <br /> • Drilling and logging numerous soil borings <br /> • Performing cone penetrometer testing (CPT) and ultraviolet-induced fluorescence <br /> (UVIF) testing,both tests in situ <br /> • Installing 20 monitoring wells (7 by Arcady and 13 by SFPP) <br /> • Collecting and analyzing numerous soil gas,soil, and groundwater samples from ' <br /> temporary borings and permanent wells <br /> • Monitoring the groundwater monitoring well network since 1992 on a quarterly or <br /> semiannual basis <br /> 1.2.2 Interim Site Remediation Activities <br /> SFPP completed significant interim remedial activities to contain and remove hydrocarbons r <br /> from the subsurface. The interim remediation activities have included the following: <br /> • NAPH Removal. Removing(bailing) NAPH from wells in the 1990s. <br /> • Groundwater Extraction and Treatment System(GWETS).A GWETS was constructed <br /> beginning in 1995 and was operational between 1997 and 2004,at which time it was shut , <br /> down for a 3-year bioremediation pilot study. During operation, groundwater was <br /> extracted from three extraction wells(RW-1,RW-3, and N-17); treated with an oil/water <br /> separator, air stripper,liquid and vapor-phase granular-activated carbon(GAC), , <br /> aeration, and temporary retention; and discharged under a National Pollution Discharge <br /> Elimination System (NPDES) permit to Trapper Slough.The aboveground portions of <br /> the groundwater treatment system were removed from the Site in October 2005 in <br /> 1.2 WBG101513183707SCOIHOLT2SA13_REPORT_FINAL , <br />