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• FIELD METHODS AND PROCEDURES The following section describes field procedures that are to be used by ENSR personnel in the performance of the tasks involved with this project 1 HEALTH AND SAFETY PLAN Fieldwork performed by ENSR and ENSR's subcontractors at the site will be conducted according to guidelines established in a Health and Safety Plan (HASP) The HASP is a document that describes the hazards that may be encountered in the field and specifies protective equipment, work procedures and emergency information A copy of the HASP will be at the site and available for reference by appropriate parties during work at the site ' 2 GROUNDWATER DEPTH ASSESSMENT ' A water/product interface probe is used to assess the liquid-phase hydrocarbons (LPH) thickness, if present, and a water level indicator is used to measure the groundwater depth in monitoring wells that ' do not contain LPH Depth to groundwater or LPH is measured from a datum point at the top of each monitoring well casing The datum point is typically a notch cut in the north side of the casing edge If a water level indicator is used, the tip is subjectively analyzed for LPH sheen • 3 SUBJECTIVE ANALYSIS OF GROUNDWATER Prior to purging, a water sample is collected from the monitoring well for subjective assessment The sample is retrieved by gently lowering a clean, disposable bailer to approximately one-half the bailer length past the air/liquid interface The bailer is then retrieved and the sample contained within the bailer is examined for floating LPH and the appearance of a LPH sheen 4 MONITORING WELL SAMPLING Monitoring wells are purged using a pump or bailer until pH, temperature and conductivity of the purge water has stabilized and a minimum of three well volumes of water has been removed The purge water is placed in 55-gallon drums and temporarily stored on-site pending evaluatign of disposal options If three well volumes cannot be removed in one-half an hour's time, the well is allowed to recharge to 80 percent of original level After recharging, a groundwater sample is then removed from each of the wells using a pump or disposable bailer The water sample is collected, labeled and handled according to the Quality Assurance Plan Water generated dunng the monitoring event is disposed of according to the accepted regulatory method pertaining to the site f5 QUALITY ASSURANCE PLAN . This section describes the field and analytical procedures to be followed by ENSR throughout the investigation ENSR J AECOM I