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• 1"'� Work Plan for Monitor Wel,...Apling and Groundwater Investigation Pilkington North America May 9,2003 Page 2 Benzene, toluene, ethyl benzene, and total xylenes (BTEX) were also not detected at or above the laboratory reported detection limit for these constituents of 0.005 mg/kg in any of the soil samples. MTBE was detected at a concentration of 0.006 mg/kg in the soil sample collected from the west side of the tank excavation but was not detected at or above the laboratory reported detection limit of 0.005 mg/kg in any of the other soil samples. SCOPE OF WORK Monitor Well Sampling and Laboratory Analyses Condor will collect groundwater samples from MW-17 and MW-18 at the project site associated with the 1986 and 1987 UST removals. At each monitor well, a Condor representative will measure the depth to groundwater from the monitor well collar with a flat tape, electrical sounding device to 0.01 foot. A single-use, disposable bailer will then be used to collect a field inspection sample. The field inspection sample will be observed for a potential floating product layer, petroleum hydrocarbon odor, and general appearance. Following this initial groundwater inspection, the well will be purged with the disposable bailer of three times the initial volume of groundwater in the well. The purge water will be tested several times during the purging for pH, conductivity, and temperature with field instruments calibrated to manufacturer recommended standards to monitor the completeness of the purge. If a monitor well is purged dry, the well will be allowed to recharge to at least 80 percent of its pre-purge volume prior to sample collection. Each groundwater sample will be collected by carefully draining the disposable bailer with a bottom-emptying device into three laboratory-supplied volatile organic analysis vials containing hydrochloric acid(HCL) as a preservative. The sample containers will be stored in a cooler chilled with ice and delivered under chain-of-custody procedures to a California certified laboratory for analyses. All field observations and measurements will be recorded on a field log during the sampling process. The groundwater samples will be analyzed for TPH-G by EPA Method 8015M and for BTEX and gasoline oxygenates by EPA Method 8260. The gasoline oxygenates consist of MTBE, ethanol, TBA, ETBE, DIPE, TAME, 1,2-DCA, and EDB. The minimum detection limit for TPH-G will be 50 }tg/L and the minimum detection limits for BTEX and the gasoline oxygenates will range from 0.5 to 13 µg/L. Groundwater Investigation Condor will conduct a groundwater investigation at the project site associated with the 1997 UST removal. Five direct push borings will be advanced at the site for the purpose of collecting shallow groundwater grab samples with a hydropunch type device. The locations of the borings are shown in Figure 3, attached. One boring will be advanced in the approximate center of the former UST location and the other four will be advanced around it. For each boring, the soil encountered will be logged in accordance with the Unified Soil Classification System. Condor anticipates that groundwater will be encountered at approximately 10 feet below the ground surface (bgs). Once groundwater is encountered, the groundwater sampling device will be pushed to approximately four feet below the surface of the water table. The outer wall of the sampling device will then be retracted, exposing the inner stainless steel screen to the groundwater. Once groundwater has entered the sampler through the screen, groundwater will be collected with a small-diameter, stainless steel bailer and gently poured into the appropriate sampling containers. The direct push sampling equipment will be decontaminated between use at each boring by steam cleaning and rinsing with de-ionized water. Bottle handling, chain-of-custody, and laboratory analysis of the groundwater samples will be in accordance with the procedures described above . for the monitor well sampling. 3 �a CONDOR