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M <br /> - <br /> t a <br /> photoioni?ation detector. The calibration of this instrument was confirmed by the field <br /> geologist each day prior to use. Upon sample extraction, brass tube ends were immediately <br /> sealed with aluminum foil and fitted with end caps to prevent the loss of volatile compounds. <br /> Each tube was placed in a separate ziploc bag and sealed with security tape. Samples were <br /> stored in a refrigerated ice chest and hand delivered to Precision Analytical Laboratory <br /> (©OHS certified) in Richmond, CA. Chain-of-custody and request for analysis forms <br /> accompanied the samples at all times(Appendix Q. <br /> 2.3 Well Construction Details - <br /> Wells NIW-5,MW-6, MW-7,VW-1 and VW-2 were. constructed during this investigation. <br /> Thew Iocations are depicted on Figure 2. Well comtruction details are explained in Sections <br /> 2.3.1 and 2.3.2, and are shown in Appendix B. <br /> _ 2.3.1 Vadose Well Con3truction <br /> Vadose wells consisted of twenty feet of well screen -oupled beneath nine feet of blank <br /> casing. Each well was fitted with a friction bottom cap. Wells were two inches in diameter <br /> and were placed in an 8 1/2 inch dianeter annulea: Casing materials consisted of Schedule ' <br /> 40 PVC. The annulus was packed with clear.#I2/12 sand from the well base to five feet <br /> above the perforation zone. The annular seal consisted of two feet of bentonite pellets <br /> overlain by cement grout. Each well was labeled.fitted with a locking cap and enclosed in a <br /> steel street box. Well construction is diagrammed on the boring logs enclosed in Appendix , <br /> B. <br /> r <br /> 2.3.2 Monitoring Well Construction <br /> Groundwater monitoring yells consisted of twenty feet of well screen, coupled beneath blank <br /> casing. Well screens were placed across the water table. Each well was fitted with a friction <br /> bottom cap. Casing materials consisted of Schedule 40 PVC.' The well annulus was packed <br /> with clean#2/12 sand from the well base to five feet above the perforation zone. The annular <br /> seal consisted of two feet of bentonite pellets overlain by cement grout. :Each well was <br /> -- labeled, fitted with a locking cap and enclosed within a flush mount steel utility box. Well <br /> construction is diagrammed on the boring logs contained in Appendix B. <br /> MZ 1-N21-911USTMat MER 4 <br /> ,f <br /> rr <br />