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1 the formation cannot be entirely eliminated by well development After the wells have been adequately developed, a sample is collected for laboratory analysis ' Subjective Anal�of Groundwater SamQles ' Groundwater samples are collected for subjective analysis from just below the air-fluid interface in a monitoring well by lowering approximately half the length of a clean bailer through the interface The bailer is retrieved and the water sample examined for floating ' product, sheen, or other subjective evidence of hydrocarbons ' Measurement of the Depth to Groundwater in Monitoring Wells The depth of the groundwater surface in a monitoring well is measured from the top of the ' well casing to the nearest 0 01 foot with a Solinst or similar electric water-level indicator The well is vented to the atmosphere before obtaining depth-to-water measurements. Venting is conducted to allow the groundwater to equilibrate to barometric pressure These measurements are combined to evaluate the elevation of the groundwater surface in each well and the slope of the groundwater surface across the site Groundwater Sam lin The static water level in each well is measured to the nearest 0 01 foot with a Solinst or similar electric water-level indicator cleaned with a laboratory-grade non-phosphate detergent and clean tap or deionized water before use in each well A clean bailer is used to obtain a sample from the surface of the water in the well for subjective analysis of hydrocarbons The sample is retrieved and examined for floating product, sheen, color, and clarity ' Approximately 3 to 5 well volumes are purged from each well with a pre-washed submersible pump or bailer to allow sampling of representative formation water All down hole equipment is cleaned with a laboratory-grade non-phosphate detergent and water before use in each well The wells are purged until pH, temperature, and electrical conductivity of the water have stabilized, as measured by portable meters calibrated to a standard buffer and conductivity standard If the well is pumped or bailed dry during purging, the water level is allowed to ' recover to at least 80 percent of the initial water level prior to sampling A sample of the formation water then is retrieved from the surface of the water in each of the ' wells with a dedicated disposable bailer and slowly transferred to laboratory-cleaned sample containers The recovered fluids from sampling in each well are directed into 55-gallon liquid ' waste drums approved for this use by the DOT until suitable disposal options are selected based on analytical results Disposal of water at an appropriate disposal facility is the responsibility of the client SHELLSIFLDMTHDS doc 3