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FIELD METHODS AND PROCEDURES <br /> 1 The following section describes field procedures that are to be used by ENSR personnel in <br /> the performance of the tasks involved with this project. <br /> ' 1. HEALTH AND SAFETY PLAN <br /> Fieldwork performed by ENSR and ENSR's subcontractors at the site will be conducted <br /> according to guidelines established in a Health And Safety Plan (HASP). The HASP is a <br /> document that describes the hazards that may be encountered in the field and specifies <br /> protective equipment, work procedures and emergency information. A copy of the HASP <br /> 1 will be at the site and available for reference by appropriate parties during work at the site. <br /> 2. GROUNDWATER DEPTH ASSESSMENT <br /> 1 A water/product interface probe is used to assess the liquid-phase hydrocarbons (LPH) <br /> thickness, if present, and a water level indicator is used to measure the groundwater depth in <br /> monitoring wells that do not contain LPH. Depth to groundwater or LPH is measured from a <br /> datum point at the top of each monitoring well casing. The datum point is typically a notch cut <br /> lie in the north side of the casing edge. If a water level indicator is used, the tip is subjectively <br /> analyzed for LPH sheen. <br /> 3. SUBJECTIVE ANALYSIS OF GROUNDWATER <br /> I �I Prior to purging, a water sample is collected from the monitoring well for subjective <br /> assessment. The sample is retrieved by gently lowering a clean, disposable bailer to <br /> i <br /> approximately one-half the bailer length past the air/liquid interface. The bailer is then <br /> retrieved and the sample contained within the bailer is examined for floating LPH and the <br /> appearance of a LPH sheen. <br /> 4. MONITORING WELL SAMPLING <br /> Monitoring wells are purged using a pump or bailer until pH, temperature and conductivity of <br /> the purge water has stabilized and a minimum of three well volumes of water has been <br /> removed. The purge water is placed in 55-gallon drums and temporarily stored on-site <br /> Ipending evaluation of disposal options. If three well volumes cannot be removed in one-half <br /> an hour's time, the well is allowed to recharge to 80 percent of original level. After recharging, <br /> a groundwater sample is then removed from each of the wells using a pump or disposable <br />