ARCHIVED REPORTS_XR0001970 - Laserfiche WebLink

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c 1� • Mr Kyle Christie April 27, 1995 Page 2 and grease [TOG]) was present Concentration of volatile organic compounds, senuvolatile organic compounds, and polychlonnated biphenyls were below detection linJts Total metals were also below detection hnuts, with the exception of arsenic and barium which were detected at concentrations of 0 0051 and 0 12 parts per million, respectively (see Attachment A) On March 2, 1992, RESNA conducted a vapor extraction test at the site (RESNA, June 15, 1992, Report 30004-5) Results of the test indicated that soil beneath the site can be remediated by vapor extraction, and the evaluated radius of influence was 30 feet. In May 1994, RESNA submitted a Problem Assessment Report (PAR [RESNA, May 11, 1994, Report No 30004-8]) to the San Joaquin County Public Health Services (SJCPHS) and the California Regional Water Quality Control Board A Final Remediation Plan (FRP) and subsequent remediation will be prepared and implemented in the future GROUNDWATER MONITORING, FIRST QUARTER 1995 . EMCON was contracted by ARCO to conduct the field work at the site Field work included measuring depths to water and collecting groundwater samples for subjective and laboratory analyses EMCON used these data to evaluate the direction and gradient of groundwater flow beneath the site On February 15, 1995, a technician from EMCON measured the depth to water and collected groundwater samples from monitoring wells MW-1 through MW-6 for subjective and laboratory analyses The field methods and procedures used are presented in Attachment A The technician did not observe floating product or product sheen on samples collected from the wells (see Table 1) The surveyed elevations of the top of casing and the depth to groundwater measurements (summarized in Table 1) were used to evaluate the potentiometric surface beneath the site On February 15, 1995, the direction of groundwater flow was toward the east with a gradient of approximately 0 003 (see Figure 3) The direction of groundwater flow is consistent with previous sampling events Groundwater elevations increased approximately 162 feet from the previous sampling event (December 1994) Groundwater samples from each well were analyzed for total petroleum hydrocarbons as gasoline (TPHG), and benzene, toluene, ethylbenzene, and total xylene isomers (BTEX) using Environmental Protection Agency Methods 5030/DHS/LUFT and 5030/8020, respectively The samples were analyzed at Columbia Analytical Services, Inc , in San Jose, California. The results of these analyses are summarized in Table 1 Copies of the laboratory analysis reports are presented in Attachment B 5AON TJ010805108051400 2AL-941dnis 1