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i Additional Soil and Groundwater Investigation Report Canepa's Car Wash(Pacific Avenue) January 21,2002 . Page 2 I31 SITE PREPARATION Appropriate permits were obtained from the PHS/EHD prior to conducting the fieldwork. The boring locations were marked with white paint and stakes, and Underground Service Alert was notified approximately 72 hours in advance of the fieldwork to locate and identify underground utilities in the vicinity of the work area. The California Regional Water Quality Control Board (CRWQCB) was notified of the fieldwork schedule at least 48 hours in advance. 3.2 CONE PENETROMETER,DIRECT PUSH AND AUGER DRILLING PROCEDURES Prior to conducting drilling activities, an on site tailgate safety meeting was held with all drilling personnel and Condor representatives in attendance. A site-specific Health and Safety Plan was discussed with and presented to all personnel for their signatures. Gregg Drilling and Testing, Inc. (Gregg) of Martinez, California, installed the CPT, hydropunch, soil, and monitor well borings. Each CPT boring (CPT-1, CPT-2, and CPT-3) was hydraulically advanced from the ground surface to the bottom of the boring. Measurements of the cone bearing pressure, sleeve friction, and dynamic pore water pressure were recorded at approximately two-inch intervals to provide a nearly continuous hydrogeologic log of the subsurface conditions. Following completion of the CPT logging procedure, the CPT borings were abandoned by grouting from the bottom of the boring to the ground surface. The three CPT logs were evaluated for the presence of likely permeable intervals or distinct lithologic 10 changes between 70 feet and 120 feet below ground surface (bgs). Three depths within this interval were then selected for discrete depth hydropunch sampling. Hydropunch samples HP-1, HP-2, and HP-3 were installed from 91 to 125 feet bgs near CPT-1 in the center of the plume. Hydropunch samples HP-4, HP- 5, and HP-6 were installed from 79 to 120 feet bgs near CPT-2 in the northeast portion of the site. Hydropunch samples HP-7, HP-8, and HP-9 were installed from 77 to 120 feet bgs near CPT-3 in the northwest corner of the site. To collect the water samples, the hydropunch sampler was advanced to the desired sampling depth, and the sampler push rod was pulled back, thereby exposing the sampler inlet screen to the formation material. The groundwater samples were collected using a stainless steel bailer lowered through the hollow push rods into the sample screen. The hydropunch borings were tremie grouted from the bottom of the boring to the ground surface upon completion of sampling. ITwo soil borings, SB-3 and SB-4, and four monitor wells, MW-9, MW-10, MW-11, and MW-12d, were installed using hollow stem auger drilling techniques. The soil borings were installed using 6-inch outside diameter continuous flight, hollow-stem auger. The borings for the two-inch diameter monitor wells were drilled using 8-inch outside diameter, continuous-flight, hollow-stem auger. The boring for MW-I I was drilled and sampled as a soil boring using 6-inch outside diameter continuous flight,hollow- stem auger. Following the soil sampling, the boring was over drilled using 10-inch outside diameter, continuous flight, hollow-stem auger, and completed as a 4-inch diameter monitor well. Soil samples from the monitor well and soil borings were collected using an 18-inch California modified split spoon sampler, every five feet, for lithologic logging, field screening, and analytical sampling purposes. The hollow-stem auger and other down-hole equipment were decontaminated between borings by steam cleaning in order to prevent cross-contamination. All drilling activities were conducted under the 0 supervision of a Condor California Registered Geologist. I CONDOR