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12.0 GROUNDWATER SAMIPLING PROTOCOL <br /> Prior to arriving at the sampling site, all sampling equipment will be washed with laboratory <br /> grade detergent, and rinsed twice with tap water, and once with deionized water. This <br /> procedure will be carried out on-site before sampling of other monitoring wells, if more than <br /> one well is to be sampled with the same sampling device. <br /> Immediately prior to sampling, the depth to water (DTW) in the well will be recorded. The <br /> thickness of free phase LNAPL on top of the groundwater, if present, will be measured using <br /> an interface probe. The procedure of monitoring is presented in Section 9.0 (Groundwater <br /> Monitoring Protocol). If free LNAPL is detected, analysis of groundwater at the interface for <br /> dissolve product will not be conducted. A product sample will be collected for source <br /> identification, as needed. If free product cannot be removed, an interval specific sampling <br /> device may be utilized to collect a sample from below the zone of free product. <br /> Before collecting groundwater sample from a well, the well will be purged until indicator . <br /> parameters (temperature, conductivity and pH) stabilize. This will entail the removal of at least <br /> three well casing volumes. Temporary storage of purged water is outlined in Section 10.0, <br /> (Well Development Protocol). The indicator parameter measurements will be taken both before <br /> and after purging of each well casing volume. Once the well is purged and indicator parameters <br /> have stabilized, a sample will be collected after the water level approaches 80 percent of its <br /> initial elevation. Where water level recovery is slow, the sample will be collected after <br /> stabilization is achieved and enough water is present to fill sample container. <br /> Cross contamination from transferring pumps (or bailers) from well to well will be avoided by <br /> utilizing dedicated equipment. Where this is not feasible, thorough cleaning of equipment will <br /> be performed between sampling rounds. Sampling will proceed from the least contaminated to <br /> the most contaminated well, if information is available before sample collection, or if it is <br /> indicated by evidence. Where several types of analysis will be performed for a given well, <br /> individual samples will be collected in the following order: <br /> 1. Volatile organics <br /> 2. Purgeable organic hydrocarbons <br /> 3. Purgeable organic halogens <br /> 4. Total organic hydrocarbons <br /> 5. Total organic halogens <br /> 6. Extractable organics <br /> 7. Total metals <br /> 8. Dissolved metals <br /> 9. Phenols <br /> 10. Cyanide <br /> 8 <br />