ARCHIVED REPORTS_XR0009094 - Laserfiche WebLink

Home Browse Search

5.0 CONCLUSIONS 1 Neighboring businesses which had appeared on State Lists of known hazaardous material storage and which have the potential to Impact the soil or groundwater beneath the subject site Included the former Exxon Service Station located at 4444 N. Pershing, the Shell Service Station located at 4445 N. Pershing Avenue, and the 7-11 located at 4501 N Pershing Avenue. All three of these neighboring sites have had recorded releases of fuels to soil, and two sites, the Shell and Exxon Service Stations have documented groundwater contamination. Regional groundwater flow has been well established to be to the north/northeast, and none of the three sites located to the east of the subject property and are believed to have impacted the _ subject site 2. Total petroleum hydrocarbons in the range of gasoline (TPH-G) were detected in the soil samples collected from MW2 through MW5 at 25 feet below grade, and in MW3 and MW4 at 30 feet below grade. The maximum concentration of TPH-G was 420 mg/kg 1n the soil sample collected from boring MW3 at a depth of 25 feet below grade 3 BTEX compounds were detected in the soil samples collected from monitor wells MW2, MW3 and MW4 at 25 feet and 30 feet below grade Xylene was the only compound detected below 30 feet below grade in MW4 at 40 feet below grade at a concentration of 0 011 µg/I. The greatest detected benzene concentration in the soil • samples was 0.59 mg/kg in boring MW3 at 30 feet below grade 4 The maximum total lead concentration detected in the sod samples collected was 12 mg/kg Total lead concentrations were substantially below the California Code of Regulations, Title 22,Total Threshold Limit Concentration value for lead set at 1,000 mg/kg. 5 Groundwater was encountered at approximately 32 feet below grade, and stabilized to approximately 30.5 feet below grade following monitor well installation and development. The inferred groundwater flow direction at the site has been determined to be to the northeast 6 TPH-G were not detected in the groundwater samples collected from monitor wells MW 1 through MW5. 7 BTEX compounds were detected in the groundwater samples from monitor wells MW2, MW3 and MW4 Benzene was detected at a maximum concentration of 18 fcg/1 in the groundwater sample collected from monitor well MW4 Benzene was the only compound in groundwater that exceeded the maximum contaminant hmits (MCLs) for drinking water as reported in "A Compilation of Water Quality Goals", Staff Report of the Regional Water Quality Control Board Central Valley Region. 1118Icd 1 17