Laserfiche WebLink
I <br />!I <br /> Conestoga-Rovers & Associates <br /> an equivalent EPA-approved detergent. Once the sampling is completed, the borings are filled to the <br /> ground surface with neat cement. <br /> Shallow Soil Vapor Point Method for Soil Vapor Sampling <br /> The shallow soil vapor point method for soil vapor sampling utilizes a hand auger or drill rig to <br /> advance a boring for the installation of a soil vapor sampling point. Once the boring is hand augered <br /> to the final depth, a 6-inch slotted probe, capped on either end with brass or Swagelok fittings, is <br /> placed within 12-inches of number 2/16 filter sand (Figure A). Nylon tubing of /o-inch inner-diameter <br /> of known length is attached to the probe. A 2-inch to 12-inch Iayer of unhydrated bentonite chips is <br /> placed on top of the filter pack. Next pre-hydrated granular bentonite is then poured into the hole to <br /> approximately and topped with another 2-inch layer of unhydrated bentonite chips or concrete, <br /> depending if the boring will hold one probe or multiple probes. The tube is coiled and placed within a <br /> wellbox finished flush to the surface. Soil vapor samples will be collected no sooner than one week <br /> after installation of the soil-vapor points to allow adequate time for representative soil vapors to <br /> accumulate. Soil vapor sample collection will not be scheduled until after a minimum of three - <br /> consecutive precipitation-free days and irrigation onsite has ceased. Figure B shows the soil vapor <br /> sampling apparatus. A measured volume of air will be purged from the tubing using a vacuum pump <br /> and a tedlar bag. Immediately after purging, soil-vapor samples will be collected usingthe appropriate - <br /> size Summa canister with attached flow regulator and sediment filter. The soil-vapor points will be <br /> preserved until they are no longer needed for risk evaluation purposes. At that time, they will be <br /> destroyed by extracting the tubing, hand angering to remove the sand and bentonite, and backfilling <br /> the boring with neat cement. The boring will be patched with asphalt or concrete, as appropriate: <br /> Vapor Sample Storage, Handling, and Transport <br /> Samples are stored and transported under chain-of-custody to a state-certified analytic laboratory. <br /> Samples should never be cooled due to the possibility of condensation within the canister. <br /> 2 <br /> R:IROCKLIN.PUBLIC\PROCEDURES & SOPSISOIL VAPOR SOP UPDATED 01-07.DOC <br />