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Working to Restore Nature GROUNDWATER SAMPLING PROTOCOL The static water level and floating product level, if present, in each well that contained ' water was measured with an QRS Interphase Probe Model No 1068018 or Solonist Water Level Indicator, these instruments are accurate to the nearest 0 01 foot These groundwater depths were subtracted from wellhead elevations,including corrections for product thickness, ' when necessary, for gradient evaluation by multiplying product thickness (PT) by a correction factor 0 8 and subtracting from the DTW (Adjusted DTW = DTW - [PT x 0 8]) ' Water samples collected for subjective evaluation were collected by gently lowering approximately half the length of a new disposable or Teflon® bailer past the air-water interface (if possible) and collecting a sample from near the surface of the water in the well The samples were checked for measurable floating hydrocarbon product All Teflon® bailers are triple washed with Alconox® and triple rinsed with distilled water prior to use Before water samples were collected from the groundwater monitoring wells, the wells were purged until stabilization of the temperature, pH, and conductivity were obtained ' Approximately four well casing volumes were purged before those characteristics stabilized The quantity of water purged from each well was calculated as follows 1 well casing volume = -rr2h(7 48) where r = radius of the well casing in feet ' h = column of water in the well in feet (depth to bottom - depth to water) 748 = conversion constant from cubic feet to gallons Gallons of water purged/gallons in 1 well casing volume = well casing volumes removed After purging, each well was allowed to recharge to at Ieast 80% of the initial water level Water samples were collected with a new disposable or Teflon® bailer, and carefully poured into 40-milliliter (ml) glass vials, which were filled so as to produce a positive meniscus Each vial was preserved with hydrochloric acid, sealed with a cap containing a Teflon® septum, and subsequently examined for air bubbles to avoid headspace which would allow volatilization to occur The samples were promptly transported in iced storage in a thermally-insulated ice chest, accompanied by a Chain of Custody Record, to a California- certified laboratory P7120 94/104 I