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T� SEC ® R •` Conceptual Site Model March 24, 2004 Page 5 3 3 SECOR International Incorporated, Assessment Report, Dated January 18, 2001 On August 30 and 31, 2000, SECOR supervised Precision Sampling (Precision) of Richmond, _ California as they advanced three soil borings (SB-2 thru SB-4) Soil boring SB-2 was advanced using hollow stem augers, SB-3/CPT-01 and SB-4/CPT-02 were cone penetrometer test (CPT) borings Three depth discrete sod samples were submitted from SB-2 for chemical analysis Soil analytical results indicated BTEX, and fuel oxygenates were below laboratory reporting limits TPHg w was detected at a concentration of 130 mg/kg (SB-2 at 27 feet bgs) Benzene was reported below laboratory reporting limits in all of the samples submitted for chemical analysis - Three depth discrete groundwater samples were submitted for chemical analysis from each boring TPHg was detected at concentrations ranging from 170 micrograms per liter(pg/L) (SB-3 at 62 5 feet bgs) to 42,000 pgA_ (SB-3 at 35 feet bgs) Benzene was detected at concentrations ranging from 1 3 ' pg/L (SB-3 at 86 5 feet bgs) to 10,000 pg/L {Seat 35 feet bgs},, Methyl tertiary butyl ether (MtBE) was detected at concentrations ranging from pg/L (SB-4 at feet bgs) to 46,000 pg/L (SB-3 at q�"' 35 feet bgs) These activities are summarized in SECOR's, Site Assessment Report, Dated January 18, 2001 Excerpts from the SECOR report are presented in Appendix D 3.4 SECOR International Incorporated, Assessment Report and Work Plan for 4 • Further Assessment, Dated March 5, 2002 ' In May 2001, SECOR supervised Gregg Drilling as they advanced four CPT borings (SB-5 through SB-8) to assess soil stratigraphy and collect discrete groundwater samples The CPT borings were advanced to approximately 95 feet bgs Pore pressure and lithologic information were used to target two to three depth-discrete groundwater sample intervals in each boring Groundwater analysis reports prepared for samples submitted for chemical analysis indicated constituents of concern at the following concentrations, TPHg at concentrations ranging from 180 I.cg/L (SB-6 at 38 feet bgs) to 100,000 pg/L (SB-5 at 42 feet bgs) Benzene at concentrations ranging from 1 6 gg/L (SB-8 at 35 feet bgs) to 6,900 pg/L (SB-5 at 42 feet bgs) MtBE at concentrations ranging from 1 9 lag/L (SB-6 at 38 feet bgs) to 280 µg/L (SB-8 at 35 feet bgs) These activities are summarized in SECOR's, Assessment Report and Work Plan for Further Assessment, Dated March 5, 2001 Excerpts from the SECOR report are presented in Appendix D 4.0 SOIL DATA SUMMARY A summary of soil analytical data presented in sections 3 1 through 3 4 is presented below 41 1 March 1995, Monitoring Well Installation Three groundwater monitoring wells were installed in March of 1995 (MW-1 through MW-3) The monitoring wells were screened from approximately 30 feet bgs to 50 feet bgs During monitoring well installation soil samples were collected at 5 foot Intervals to a depth of approximately 50 feet bgs Soil samples selected for analysis were analyzed for TPHg and BTEX Sol] samples from MW- 1 were additionally analyzed for total petroleum hydrocarbons as diesel (TPHd) and total oil and r 11Chpvror1\920331REPORTSICSMICSM 92033(REV 8)doc