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4.4 Groundwater Elevations • Each monitoring well was opened and expandable caps were removed. • Each well was allowed to equilibrate to atmospheric pressure for a minimum of 30 minutes. • A water level meter was used to measure the depth-to-groundwater in each monitoring well. • The depth, time, and visual observations regarding well access, condition, security, etc., were recorded on Water Level Data Sheets. 4.5 Purging • The volume of standing water in each monitoring well was calculated using the diameter of the well, the measured depth-to-water, and the depth-to-bottom. The volume was recorded on the Well Sampling Data Sheet for each well. • Monitoring wells MW-5 and MW-6 were purged using an electronic submersible pump. Monitoring well MW-8 was purged using a new disposable polyethylene bailer. • During the purging process, the indicator parameters of pH, conductivity, oxidation reduction potential, and temperature were measured. • Visual observations of color and odor were also monitored in purged wells. • The time, readings, and visual comments were recorded on Well Sampling Data Sheets. • Each well was purged of three well volumes. • Purge and decontamination water was transferred to 55-gallon drums labeled and stored on site. 4.6 Groundwater Sample Collection • Groundwater samples were collected by lowering a previously unused, disposable, polyethylene, bottom-filling bailer into the well. • When completely full, the bailer was carefully retracted from the well casing. • The water was transferred from the bailer to the appropriate certified clean sampling containers. • Each VOA was immediately capped. The vials were inverted and gently tapped to check for the presence of air bubbles. If any bubbles were visible, a new vial was filled and confirmed to be free of any air bubbles. • The samples were labeled with the following information: — Sample ID Date and Time Sample Collected — Location Sampler's Initials • Sample information was documented on a Chain-of-Custody form. • The samples were placed in an ice chest chilled with ice. • Upon completion of the sampling activities, each well was closed and secured by replacing the well cap and lid. GHD SOP GW Sampling 2 of 3 Rev 2114