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•Jun 6 1995 I +PM IEG TEr,F IIHOGIEz. No 2615 P 8/3A 95-WP 103 05 Treatment well groundwater sampling • - Perimeter wells groundwater sampling Sampling and analytical procedures were performed following stringent methods outlined m the Quality Assurance/Quality Control Plan and Samphng and Analysis Plan developed and approved for this project. Pilot Boring and Soil Sampling The pilot boring was drilled using a dual-tube percussion drill ng equipped with a down-hole hammer and California-modified split-spoon samplers Soil samples were collected virtually continuously for the following objectives • Geotechnical analysis Chemical analysis • Nficrobiological analysis • Lithologic description and field screening Baseline Groundwater Sampling Groundwater samples were collected prior to system startup from wells scheduled to be used for the Iong-term monitoring to establish baseline chemical conditions A wide range of chemical analyses were performed mcludmg VOC, metals, general minerals and water quality parameters Baseline samples were not collected from 3IPW1, PW7, or PWS which were added to the monitoring network after startup Operational Monitoring The 19-month operational mowtoring consisted of air monitoring and sampling, treatment well groundwater sampling, and perimeter wells groundwater sampling Air Monitoring and Sampling. The primary objectives of the air mowtonng, sampling and analysis program were to monitor the system operating parameters, to evaluate the removal rates of VOC's from the groundwater, and to evaluate the efficiency of the off-gas treatment units This consisted of recording air flow parameters including linear flow velocity, relative humidity, temperature, vacuum/pressure, and relative VOC concentrabons at the air intake pipe and at four ports installed in the above-ground airstream piping Air samples were also collected primarily from port V2 and V3 (Figure 3) for laboratory analysis of VOC concemtratioas Treatment Well Groundwater Sampling. Groundwater samples were collected frequently (approximately 165 rounds) from the two-inch diameter monitoring wells affixed to the WB treatment well Concentrations in these wells (WI and W3) are considered to represent the influent and effluent groundwater conditions, respectively Initially, sampling frequency was very rapid at startup, reducing to twice per week months 2-6, and finally to biweekly for the following 12 months Analysis consisted of VOC's on every sample, as well as six rounds for alkalinity, nitrogen, phosphate, BOD, COD and carbon dioxide, and three rounds for microbiological analysis. Field parameters (temperature, specific conductance, pH and dissolved oxygen)were also recorded on each sample round • Perimeter Wells Groundwater Sampling. Perimeter wells were sampled for VOC analysis monthly for the first sax months, and bimonthly for the following 12 months Field parameters (temperature, specific conductance, pH and dissolved oxygen) were also recorded on each sample round 6