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.� rs • GENERAL FIELD PROCEDURES General field procedures used during fluid level monitoring and groundwater sampling activities are described below FLUID LEVEL MONITORING Fluid levels are monitored in the wells using an electronic interface probe with conductance sensors The depth to liquid-phase hydrocarbons (LPH) and water is measured relative to the well box top or top of casing Well box or casing elevations are surveyed to within 0 02 foot relative to a county or city benchmark GROUNDWATER SAMPLING Groundwater monitoring wells are purged and sampled in accordance with standard regulatory protocol Typically, monitoring wells that contain no LPH are purged of groundwater prior to sampling so that fluids collected are representative of fluids within the formation Temperature, pH, and specific conductance are typically measured after each well casing volume has been removed Purging is considered complete when the specified number of casing volumes of fluid have been removed and the three (3) parameters (pH, conductivity, and temperature) have stabilized (see groundwater sampling field notes for volume removed) Samples for laboratory analysis are collected without further purging if the well does not recharge within 2 hours to 80% of its volume before purging The purge water is either (1) pumped directly into a licensed vacuum truck, or(2) treated and disposed onsite using the TRC Alton Geoscience Mobile Groundwater Treatment Trailer, or (3) temporarily stored in labeled drums prior to transport to a treatment/recycling facility If an automatic recovery system (ARS) is operating at the site,purged water may be pumped into the ARS for treatment . In monitoring wells that are purged and contain measurable LPH, the purged water and LPH removed from wells will be either pumped directly into a licensed vacuum truck and removed from the site, or temporarily stored in labeled drums pending transport to an approved treatment/recycling facility With respect to wells that have been designated as "no purge", the wells will be sampled without bailing or pumping fluids from the well prior to collecting the sample In addition, no purge samples are typically collected from active pumping wells GROUNDWATER SAMPLE COLLECTION Groundwater samples are collected by lowering a %Z to 4-inch-diameter, bottom-fill, disposable polyethylene bailer to dust below the static water level in the well The samples are carefully transferred from the check-valve-equipped bailer to the container specified by the laboratory method The sample containers are filled to zero headspace and fitted with Teflon-scaled caps Each sample is labeled with the protect number, well number, sample date, and sampler's initials, then transported to a state-certified laboratory for analysis Samples remain chilled prior to and during shipment to an analytical laboratory Chain of custody protocol is followed for all groundwater samples selected for laboratory analysis The chain of custody form(s) accompanies the samples from the sampling locality to the laboratory, providing a continuous record of possession prior to analysis When a freight or overnight carrier ships samples, the carrier is noted on the chain of custody form DECONTAMINATION Nitrile gloves are worn at all times during monitoring, sampling, and purging activities Typically, gloves are changed between each well All monitoring, sampling, and purging equipment that could contact well fluids is either dedicated to a particular well or cleaned prior to each use in a Liqui-nox solution followed by two rinses the first rinse in tap water and the final rinse in delonized water P Iwsproglgmsforms\OENERAL FIELD PROCEDURES doc