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r • � Apnl 24, 1989 File No 1705-2 APPENDIX A - SOIL AND GROUNDWATER DRILLING, WELL INSTALLATION, f SAMPLING AND SAMPLE HANDLING PROCEDURES Sampling Techniques ! All test borings have beenenerall drilled _ CME-55 truck- mounted drill rigs equipped with 6-inch diameter continuous flight t au eand /or with 3 1/4 or 3 3/4 1 D hollow stem flight augers All test borings a e logged by our field engineer, who also obtains representative soil samples for laboratory testing Soil samples are taken at 5 foot intervals or less as instructed by the field engineer when field conditions warrant it Relatively undisturbed soil samples are obtained by driving a 2 0 inch Modified Califor- nia Sampler or a 2 5 inch Modified Porter Sampler containing thin brass liners into the bottom of bonngs The procedures used in obtaining these samples are identical to the Standard Split Spoon Sampler (ASTM D-1586-67) When the sampler is withdrawn from the borings, the brass liners containing the samples are removed, field examined, and sealed for later laboratory testing After field examination, soil samples for hydrocarbon concentration testing are sealed with aluminum foil, capped with plastic endcaps, and wrapped in duct-tape To further preserve the samples, the samples are then placed in a refrigerated ice chest for trans- portation and storage All soil samples are tested in the field with a Gastech combustible gas detector for gas and vapor Based on the field analysis, the on-site soils are prelimi- nary evaluated in the field as to the extent and amount of contamination Readings from each sample are recorded in the field daily log and are presented in the boring logs of our final report Groundwater sampling techniques are the same as described in the CRWQCB guide- lines Briefly, water samples are taken after the well has been developed and stabilized the sand or gravel pack surrounding the perforated sections See Monitoring Well In- stallation of this letter for well development techniques Water samples are collected by using a teflon bailer that is thoroughly washed and cleansed prior to sampling other monitoring wells A trisodium phosphate (TSP) solution is used to wash the bailer and then it is rinsed with clean water The water samples are then collected in either one- liter bottles for laboratory analysis EPA Modified 8015 - TPH, Total Petroleum Hydro- carbons or in VOA vials for EPA 602 and 624 In each type of sample bottle, each are sealed with a teflon-lined cap with no head space present in the sample container • water samples are then placed in a refrigerated ice-chest for transportation and storage A-1