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t Page.2; K%%ik 1i15P)i originally labelled MW-1, but has been renamed KI'-3 in this investigation. it is our understanding that Geological Technics performed routine groundwater monitoring of this well in April 1990. Total petroleum hydrocarbons in the gasoline; range (TPH-b) were detected at a concentration of 81,000 ug/l (ppb), and benzene was detected at a concentration of 2,107 ppb. Toulene, ethylbenzene, and xylene were also detected at elevated levels. Subsequently, EHD requested further assessment of the extent of the plume of contaminated groundwater, but no work was performed until the present investigation was undertaken in December 1994. i 3.0 MONITOR WELL INSTALLATION 3.1 Drilling and Sampling Procedures On December 22, 1994, monitor wells U-1 and KP-2 were installed by Soils Exploration l Service of Benicia, California. The wells were drilled with a CME-55 hi-torque hollow-stem auger drilling rig using 10-inch augers. A 140-pound hammer was used to collect soil samples in a California-modified split-spoon sampler loaded with three 6-inch brass sample sleeves, and the ' number of hammer blows needed to pound the sampler 18 inches was recorded on the boring log. The logs are included in Appendix A. After retrieval, the sleeves were removed from the sampler and the bottom sleeve was covered with teflon sheets, sealed with plastic end caps, labelled, and placed in a cooled ice chest. Soil was then extruded from the middle and upper sleeves and described on the boring lob. A representative sample was placed in a plastic sample bag and a Photovac Microtip HL-2000 photo-ionization detector (PID) was used to screen the sample for the presence of organic vapors. The PID reading was also recorded on the boring log. 3.2 Laboratory Analysis Samples were collected at 10, 15, and 20 feet in each boring and were transmitted under chain-of-custody to McCampbell Analytical in Pacheco, California for.analysis. All samples were analyzed according to EPA method 8015 modified for total petroleum hydrocarbons in the ; gasoline range (TPH-b) and EPA 8020 for benzene, toluene, ethylbenzene, and xylene (B"TEX). One sample was also anlayzed for total lead, because leaded gasoline was formerly distributed at u the site. 3.3 Well Completion Both wells were completed as groundwater monitoring wells by installing screened 4-inch-diameter PVC pipe from 30 to 15 feet and blank PVC pipe from 15 feet to the surface. Details of the sand pack and grouting are illustrated in Appendix A. Grouting was witnessed and approved by Mr. Michael Infurna of EFID. Drill cuttings and rinseate water were stored on site ' in 55-gallon DOT-approved steel drums. {