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*ftw, Clayton `.� ENVIRONMENTAL CONSULTANTS According to information from the Orchard Supply Hardware-Tracy site located at the comer of MacArthur Drive and Grantline Road approximately 114-mile away, the water table is approximately 10 to 15 feet below ground surface (bgs), and the i.• groundwater flow direction is north. On May 6, 1993, one borehole was installed to a depth of approximately 20 feet bgs L with an 8-inch hollow-stem auger from a truck-mounted rig. The borehole was converted into a monitoring well. B&F Drilling Co., Inc. of Rancho Cordova, California, provided the borehole and well installation services under subcontract to Clayton. Figures 1 and 2 show the location of the borehole. Soil samples were collected at approximately 5 and 10 feet bgs. Lithologic logs recording the soil types underlying the site were maintained by Clayton's geologist. L. Soil was screened for hydrocarbon contamination with an OVM. The borehole logs are presented in Appendix E. Waste drill cuttings was placed into a DOT-approved 55-gallon drum for proper disposal at a later date. Monitoring well MW-1 was constructed of 2-inch diameter schedule 40 PVC flush-threaded casing. Clayton developed the newly installed monitoring well on May 9, 1993. This was done to stabilize the filter material and remove turbid water caused by drilling operations. ` Groundwater was sampled from monitoring well MW-1 on May 12 and June 21, 1993. Field sampling data sheets are included in Appendix E. The water generated from well development and sampling was placed into a DOT- approved 55-gallon drum for proper disposal at a later date. The drum was labeled with the name of the site, address, well number, and the drum contents, and left at the site pending laboratory analysis. 4.4 LABORATORY ANALYSIS The soil and groundwater samples were analyzed by the following methods: -- Environmental Protection Agency (EPA) Method 8015-modified for diesel fuel • EPA Method 8020 for benzene, toluene, ethylbenzene, and xylenes (BTEX) �. EPA Method 413.2 for total recoverable oil and grease • EPA Method 8315 for formaldehyde All samples were transported to Clayton's laboratory under chain-of-custody documentation. 4.1 SOIL SAMPLE ANALYSIS v Analytical results revealed diesel, BTEX, total recoverable oil and grease, and formaldehyde were below detection limits. The laboratory analytical report is included L as Appendix F with chain-of-custody documentation. 2 i L r