Laserfiche WebLink
containers. A hand-driven sampler holding the sample container may be used. To reduce the potential for <br /> cross-contamination between samples, the sampler is cleaned betwe n each sampling event. Upon recovery, the sample <br /> container is sealed to minimize the potential of volatilization andcross-contamination prior to chemical analysis. Soil <br /> sampling tubes are typically closed at each end with Teflon'sheeting and plastic caps. The soil sample is collected, labeled <br /> and handled according to the Quality Assurance Plan. <br /> Ground Water and Liquid-Phase Petroleum Hydrocarbon Depth Assessment <br /> A water/hydrocarbon interface probe is used to assess the liquid-phase petroleum hydrocarbon (LPH) thickness, if present. <br /> A water level indicator is used to measure the ground water depth iii monitoring wells that do not contain LPH. Depth to <br /> ground water or LPH is measured from a datum point at the top of each monitoring well casing. The datum point is typical a <br /> notch cut in the north side of the casing edge. If a water level indicator is used, the tip is subjectively analyzed for <br /> hydrocarbon sheen. <br /> Subjective Analysis of Ground Water <br /> Prior to purging, a water sample is collected from the monitoring well for subjective assessment. The sample is retrieved by <br /> gently.lowering a clean, disposable bailer to approximately one-half the bailer length past the air/liquid interface. The bailer <br /> is then retrieved, and the sample contained within the bailer is examined for floating LPH and the appearance of a LPH <br /> sheen. <br /> Monitoring Well Purging and Sampling <br /> Monitoring wells are purged using a pump or bailer until pH,temper ture and conductivity of the purge water has stabilized <br /> and a minimum of three well volumes of water has been removed. 11 three well volumes can not be removed in one half an <br /> hour of time, the well is allowed to recharge to 80 percent of the original level. After recharging, a ground water sample is <br /> then removed from the well using a disposable bailer. The water sadiple is collected, labeled and handled according to the <br /> Quality Assurance Plan. Water generated during the monitoring ev nt is disposed of according to the regulatory accepted <br /> method pertaining to the site. <br /> UALITY ASSURANCE PLAN <br /> General Sample Collection and Handling Procedures <br /> Proper collection and handling are essential to ensure the quality f a sample. Each sample is collected in a suitable <br /> container, preserved correctly for the intended analysis and store prior to analysis for no longer than the maximum <br />