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PRIVILEGED & CONFIDENTIAL Groundwater EIetvation Measurements On August 27, 1998 the static groundwater elevations were measured in the four groundwater monitoring wells, by lowering a decontaminated Solinst groundwater elevation probe and measuring the groundwater elevation to the nearest 0.01 foot. Well elevation data are included in Table 1, attached. The calculated groundwater elevation indicates that the groundwater gradient is approximately 0.005 to the northeast. A groundwater contour map is presented as Figure 3, attached. A rose diagram of historic groundwater flow directions between February 1997 and August 1998 is presented as Figure 7, attached. Groundwater Monitoring and Sampling On August 27, 1997 the monitoring wells were purged a minimum of three well volumes using a submersible pump. During purging of groundwater wells, measurements collected of the pH, temperature, turbidity and electrical conductivity showed stabilization to within approximately 5% in each well. Purge volumes ranged from approximately 45 to 55 gallons. The wells were allowed to recharge a minimum of 80% before sampling. Samples were collected from each monitoring well along with a blind duplicate. Water samples were collected by lowering a new disposable two-inch Teflon bailer below the ' static water level, and raising the bailer slowly in order to minimize agitation of the water sample in the bailer. Water was discharged from the bailer through a bottom discharge valve into the sample container at a rate slow enough to minimize agitation of the liquid. The sample container was filled to the top(from the bottom up) and overfilled leaving no headspace. The samples were collected in laboratory-approved glass 40 milliliter vials. Following collection of the samples, the vials were labeled with the sample number, collection date and project number, placed into a cooler chilled to approximately 4° C (40° F), and retained for laboratory analyses. Quality Assurance/Quality Control To increase the confidence levels in the data obtained and minimize the likelihood that judgments were made from potentially erroneous data, a quality assurance/quality control (QA/QC)program was implemented. ' The program includes formal procedures for drilling, sampling,p g, decontairunation, instrument calibration, documentation of field activities and calculations, and peer review. Routine QC procedures were performed by the laboratory, and included daily calibration of instruments, percent surrogate recoveries, and analysis of matrix spikes and matrix spike duplicates. The laboratory reported the results to be within acceptable percent error with no ' results exceeding the laboratory-established control Iimits. Decontamination The hollow-stem augers and well purging equipment were steam-cleaned prior to their use in the boring or monitoring wells. The sampler was decontaminated between sampling ' 6 199075-WFB,Stockton Ph.11 and Quart.Groundwater