Laserfiche WebLink
r <br /> 1.0 INTRODUCTION <br /> Gribi Associates is pleased to submit this report on behalf of Reid Plastics documenting a recently- <br /> completed soil boring investigation conducted at the Reid Plastics underground storage tank(UST) <br /> site located at 75 West Valpico Road in Tracy, California (see Figure 1 and Figure 2). The soil <br /> boring investigation included the drilling and sampling of three soil borings(IB-IA,IB-1,and IB-2) <br /> at the site using direct-push coring equipment. The goal of this investigation was to characterize soil <br /> and groundwater quality in the vicinity of the former fuel dispenser in order to attempt to obtain <br /> regulatory closure for this UST site. <br /> 1.1 Site Background <br /> The project site is located on the north side of West Valpico Road,approximately one-half mile east <br /> from South Tracy Boulevard, on the south side of Tracy, California. The former diesel fuel UST <br /> system was located immediately south from the north project site property line. An apparent water <br /> supply well and pump house are present on the adjacent north parcel, approximately 130 feet <br /> northeast from the former fuel dispenser island. <br /> One 12,000-gallon single-walled steel diesel UST was removed from the site by Bowen <br /> Construction-Engineering on January 18, 1999. Three soil samples(one sample taken beneath each <br /> tank end and one sample taken beneath the middle of the tank) collected by Mr. Jim Gribi, RG, at <br /> . a depth of about 14 feet below surface grade in native soils contained no detectable levels of Total <br /> Petroleum Hydrocarbons as Diesel (TPH-D); Benzene, Toluene, Ethylbenzene, and Xylenes <br /> (BTEX); or Methyl-t-butyl Ether(MTBE). Two soil samples were collected beneath the removed <br /> fuel dispenser island. One of these samples collected at about three feet in depth contained 2,300 <br /> parts per million (ppm) of TPH-D and no detectable BTEX or MTBE constituents. One sample <br /> collected at about five feet in depth beneath the removed dispenser contained 1,900 ppm of TPH-D <br /> and no detectable BTEX or MTBE constituents. One soil sample collected at about four feet in <br /> depth beneath removed product delivery piping contained no detectable levels of TPH-D, BTEX, <br /> or MTBE constituents. <br /> Approximately 155 cubic yards of soil excavated during UST removal activities were stockpiled in <br /> four stockpiles based on obvious evidence of hydrocarbon contamination. Two of the stockpiles <br /> exhibited obvious evidence of hydrocarbons, and soil samples collected from these stockpiles <br /> contained elevated levels of TPH-D,with no significant detection of BTEX or MTBE constituents. <br /> With the exception of one soil sample that contained 1,200 ppm of TPH-D, five soil samples <br /> collected from the other two "clean" stockpiles contained no significant levels of TPH-D, BTEX, <br /> or MTBE constituents. Based on these results,the UST excavation cavity was backfilled by Bowen <br /> Construction-Engineering using both clean imported fill and soils from the two "clean"stockpiles. <br /> It is our understanding that Bowen Construction-Engineering conducted additional overexcavation <br /> of the fuel dispenser area in August 1999. According to Mr. Merlin Bowen of Bowen Construction- <br /> Engineering,this overexcavation was extended to a depth of about 14 feet below surface grade,and <br /> field evidence indicated that all fuel-impacted soils had been removed. No groundwater was <br /> encountered in the excavation cavity. The fuel dispenser overexcavation cavity was backfilled with <br /> clean sand and road base in early October 1999. <br /> GRl B I Associates Pa e. REPORT OF SOIL BORING INVESTIGATION <br /> g REID PLASTICS LIST SITE/GA 172-01-01 <br />