SITE INFORMATION AND CORRESPONDENCE

Home Browse Search

OEOMATRIX Mr. C. Dean Hubbard California Regional Water Quality Control Board Central Valley Region May 24, 2004 Page 3 Four borings will be advanced north (assumed downgradient direction)of borings GMX-15 and GMX-16 for the collection of grab groundwater samples (Figure 3). These borings ill. be advanced using a hydraulically driven core barrel and drive sampler a depth of approxi- mately 20 feet bgs based on the depth to groundwater(12 to 15.5 feet bgs)p Y served in monitoring wells at the adjacent TAOC Tracy Pump Station(Renown)property. A continuous core of the soil will be collected and examined from each location and the lithol- ogy will be logged by a Geomatrix field geologist. In addition, organic vapor meter(OVlvt) readings will be taken and recorded at various depths. Grab groundwater samples will be collected following installation of a temporary well con- sisting of 1-inch-diameter polyvinyl chloride(PVC)blank casing and 5 feet of 0.01-inch slot well screen. Each groundwater sample will be collected using a disposable bailer and will be decanted into the appropriate containers provided by the laboratory. Grab quantified as gasoline (TPHg) sam- ples will be analyzed for total petroleum hydrocarbons(TPH) enzene, and and as diesel (TPHd)using EPethodt802 hod80and polynuclear 15M;benzene, arom tic hydrocarbons(PAHs) xylenes (BTEX)using EPA M Y TPHd analyses will using EPA Method 8270 with a selective ion monitoring system(SIM). be performed both with and without a silica gel preparation procedure. If affected soil is observed in the soil core from a boring, a grab groundwater sample will not be collected. Instead a soil sample will be collected at a depth where the most visually affected soil is observed and at least one soil sample will be collected above a depth of 10 feet bgs for potential use in a human health screening evaluation. If warranted, soil samples will be collected in butyrate sleeves sealed with Teflon sheets,end caps, and silicon tape. If collected, soil samples will be analyzed for TPH quantified as crude (TPHc) using EPA Method 8015M,BTEX using EPA Method 8021, and PAHs using EPA Method 8270 SIM. Soil and groundwater samples will be labeled and stored in an ice-cooled chest until transfer to a California-certified laboratory under Geomatrix chain-of-custody procedures. All bor- ings will be grouted to ground surface using a tremie pipe upon completion. Several samples will be submitted to the laboratory for quality assurance/quality control (QA/QC)purposes. One travel blank,provided by the laboratory,will accompany grab groundwater sample containers throughout the trip from the laboratory to the field and back to the laboratory. The travel blank will be analyzed for TPHg and BTEX. One equipment blank will be collected using a disposable bailer. The equipment blank will be submitted to the laboratory,however, it will onsyobe aanmal Beare collected,one will b there is a question regarding specified for matrix the grab groundwater samples. If p spike/matrix spike duplicate analysis for TPHc,BTEX, and PAHs.