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+ JJAr ,fes'° VYV wt ' 5 12 November 2009 ��jAl�,,Gt AGE-NC Project No. 98-0497 h r/+ Page 4 of 5 C� t 2{' d d 0' p An expendable vapor point will be placed into a poin holder at the bottom of an assembly of 1.125-inch diameter hollow drive rods. The assembly w 11 then be advanced to the specified depth and r`etfacted approximately twelve inches in order to disengage the expendable point and expose a column of strata from which soil vapor can be extracted.A single use, 1/4-inch diameter disposable polyethylene(or teflon)tubing is then attached to a tubing adapter equipped with an O-ring to ensure a vacuum-tight seal. The adapter assembly is then 10 ered through the center of the Geoprobe hollow drive rods to the specified depth and secured by threading into the expendable vapor point i holder. �� g��.y-�r Tl.�''I�►-�1,' 4 Above ground, the surface around the soil v or sampl r will be sealed with a bentonite sealant to prevent ambient air intrusion. To ensure hat a reliab a soil-vapor sample is collected with no ambient air breakthrough down the p obe rod, an appropriate amount of rubbing alcohol (approximately G to 8 ounces)will be ap lied to adequat ly wet a cotton towel;the wetted towel will ,� e be completely wrapped°around the b se of the robe od where it contacts the surface and the bentonite seal. The end of the of exh ne tubin 'll e attached to a 1/4�" fitting, which is then �1,L�n�� attached to a the inlet end of a — --L7 . be. The outlet end of the TO-17 tube is attached to 1/4" Tygon tubing, which is attached to a low flow vacuum pump. Following the desired pump time' duration, the pump is shut off, and the TO-17 tube is r moved from the assembly End plugs are •� replaced on both end7of the TO=17 sample tube,and the tube is labeled with the boring designation; p depth,time,date and sampler's initials. Samples are to d on to a chain-of-custody form and placed .r r in a cooler.with ice, and delivered to a CDPH-certified laboratory(i.e.Air Toxics Ltd.)for analysis of the chemical constituents listed in Section 2.2.Vapo sample collection utilizing a TO-17 tube, provided by Air Toxics Ltd., are included in Appendix B. tprabA � alAfter collection of the sample, soil-vapor from the polyethylene tubing will be monitored for the � .presence of volatile organics using a flame-ionization detector(FID). , 3.3. SOIL SAMPLE COLLECTION Soil samples will be collected at discreet five-foot i tervals using a 1.25-inch Geoprobe soil sampling assembly loaded with four six-inch stainless st el sleeves.Upon sample retrieval,the ends it of the second sleeve will be covered with Teflon sheets, capped and sealed with tape. ®SCJ t Appropriately sealed and labeled samples will be pl ced in a chilled container under ice and transported under chain-of-custody procedure to a CDPH-certified laboratory for analysis of the chemical constituents in Section 2.3.Each sample sleevc will be labeled with the boring designation, depth, time, date and sampler's initials. Soils encounter.-d in the borings will be visually classified by an AGE geologist in accordance with the Uni fed Soil Classification System (USCS). Additionally, soil samples will be field-screened for the presence of volatile organic compounds Advanced GeoEnvironmental,Inc.