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16 May 2012 AGE-NC Project No. 12-2113 Page 4 of 5 pressure is created around the Tedlar bag, which inflates, allowing the soil-vapor sample to enter directly into the bag via the inlet port. When the sample is collected, the negative pressure in the chamber is reduced and the sample bag is sealed, labeled, log on a chain- of-custody form, and place into a dry cooler (room temperature). Subsequently, all of the collected soil-vapor samples will be delivered to a CDPH-certified laboratory for analysis of VOCs in accordance with EPA-method 82606. After sample collection, soil-vapor from the polyethylene tubing will be monitored for the presence of volatile organics using a photo-ionization detector (PID) pre-calibrated to isobutylene. Additionally, AGE proposes to utilize 70% isopropyl alcohol (rubbing alcohol) as a leak detection tracer compound to ensure that a reliable soil-vapor sample is collected from each soil boring with no ambient air breakthrough down the probe rods. AGE will apply an appropriate amount of rubbing alcohol(approximately 8 ounces)to adequatelywet a cotton towel; the wetted towel will be completely wrapped around the base of the probe rod where it contacts the surface and the bentonite seal. Thereafter, a soil-vapor sample will be collected. Isopropyl alcohol analysis will verify the validity of each sample. GRAB GROUND WATER SAMPLE COLLECTION AND ANALYSIS For the collection of grab ground water samples, soil probe borings will be advanced to the top of the ground water table or approximately 40 feet bsg. Once ground water has been encountered, a Geoprobe push-driven water sampling device will be advanced into the water-bearing zone. Grab ground watersamples will be collected using a Geoprobe Screen Point 15 Ground Water Sampler TM (GWS)fitted with a new one-half inch 0.010-inch slotted temporary well screen. Ground water samples will be extracted using inertial action by lowering Teflon tubing through the hollow center of the push rods into the screen section. Each ground water sample will be collected into four laboratory supplied 40-ml volatile organic analysis(VOA)vials without preservative. Following collection,appropriately sealed and labeled samples will be placed in a chilled container under ice and transported under chain-of-custody procedure to a CDPH-certified laboratory for analysis of VOCs in accordance with EPA-method 82606. Each sample container will be labeled with the boring designation, time, date and sampler's initials. EQUIPMENT DECONTAMINATION Prior to use, all sampling tools used for sample collection will be thoroughly rinsed with clean water after being washed with a solution of Alconox. All probing rods will be cleaned prior to advancement at each probe boring location. Advanced GeaEnviranmental,Inc.