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FIELD PROCEDURES <br /> Subjective AnalXsia gf Moollor-ing-W—eLb <br /> Groundwater samples are collected for subjective analysis from just below the air-fluid <br /> interface in a monitoring well by lowering approximately half the length of a clean Teflon <br /> bailer through the interface. The bailer is retrieved and the water sample examined for <br /> floating product, sheen, or other subjective evidence of hydrocarbons. <br /> Measurpment qJ the DegthtoGround Water in Monitoi ing Wells <br /> The depth of the ground-water surface in a monitoring well is measured from the top of the <br /> well casing to the nearest 0.01 f.ot with a Solinst water-level indicator. <br /> Purging`and Samplingof Monitoring Well <br /> Before sample collection, a minimum of 4 casing volumes of ground water are purged V am <br /> each monitoring well using an electric submersible pump. The volume must be sufficient <br /> to produce stable temperature, pH, and conductivity measurements on field instruments. <br /> After the wetl is allowed to recover to static levels, a ground-water sample is collected by <br /> • n„ lowering a clean Teflon bailer past the air-water interface. The bailer is retrieved and the <br /> sample is slowly transferred to laboratory-cleaned 40-milliliter glass vials that contain <br /> concentrated hydrochloric acid as a preservative. The vials are completely filled, thereby <br /> eliminating headspace. Labels that show the site 'identification number, the date and time <br /> of sample collection,the preservative used,and the sample identification number are affixed <br /> to the vials. <br /> The samples are stored in m ice chest with ice according to sample preservation protocol <br /> for the respective analyses. The field geologist initiates a Chain of Custody Record listing <br /> each sarnple number, the site identification number, and the date sam-led. This record <br /> accompanies the samples to the analytical laboratory. <br /> i <br /> ApP/10OF 4`OOSYSAOMS <br />