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WGR WESTERN GEOLOGIC RESOURCES INC. STANDARD OPERATING PROCEDURE RE: SOIL VAPOR SURVEY SOP 1 VAPOR POINT INSTALLATION For a standard soil vapor survey (SVS), a minimum of 8 to 15 vapor points are installed and samples. The vapor points are drilled with a Giddings Soil Probe using 2 inch diameter solid flight augers. Two different depths are drilled at each sampling location. The depths are dependent upon depth to first ground water, soil conditions, underground obstacles and the specific objectives of the investigation. Five-eighth in stainless steel hollow rods equipped with a slotted aluminum sampling tip and 3/16 in diameter polypropylene tubing are installed in the augerhole and driven to the desired sampling depth. The hollow rods are then pulled back about 0.2 ft to expose the slots of the sampling tip for vapor extraction. Once the shallow vapor point has been sampled the hollow rods and tubing are removed and the hole is advanced to the second desired sampling depth and sampled as above. The augerhole is abandoned with quick setting cement after all instrumentation is removed. In some cases, the points cannot be driven any deeper and are set at the drilling depth. Auger holes are not drilled into ground water. However,if ground water is encountered the augerhole is grouted up immediately to above the ground water level. VAPOR SAMPLING TECHNIQUE All vapor points will be purged with a SKC Aircheck sampling pump prior to sampling. This is done to remove any air that may remain from the installation of the vapor point. Samples are extracted from the vapor point and collected in 250 microliter (ul)gas tight syringes. The entire 250 ul volume of the syringe is injected into the Photovac 10550 portable gas chromatograph (GC) for analysis. This volume is used because the GC is calibrated to a 250 ul standard of benzene or benzene, toluene and xylene (BTX). If extracted vapor appears to contain high enough concentrations to saturate the GC column,the sample is diluted by partially filling the syringe with a desired volume of soil vapor and filling the remainder of the syringe with ambient air. The diluted vapor sample is injected into the GC for analysis. If the chromatograph peaks exceed the scale of the GC,thevalues are reported as"greater than". QUALITY ASSURANCE/QUALITY CONTROL PROTOCOL Prior to sampling,all syringes are checked for any detectable vapors. This quality assurance / quality control (QA/QC)check is conducted by collecting 250 ul of ambient air and injecting it into the GC for analyses. The column is also checked periodically to ensure that it is not contaminated by injecting the carrier gas,hospital grade compressed gas, directly into the column. If any residual vapors remain, the GC will detect them. The syringes and columns are replaced if significant contamination is found during the process. Vapor point drilling and drive equipment are cleaned with water and trisodium phosphate (TSP) prior to drilling each new sampling point. The syringes are cleaned and purged with carrier gas between sampling points and they are steam-cleaned between projects. Method detection limit calculations have shown that detectable concentrations of volatile hydrocarbons,and/or benzene,greater than 6 ppm have a 95-percent confidence level as determined by the method detection limit procedure in 40 CFR,Part 136,Appendix A: Definition and Procedure for the Determination of the Method Detection Limit. Concentrations less than 6 ppm are within the instrument's capability of detection,but the confidence limit is extremely low. Therefore,any readingless than 6 ppm is reported as"non-detectable. SOKOAS