Laserfiche WebLink
Clayton <br /> EMIR01� xTA! <br /> CGN5U,,TAtiT5 - <br /> 6.3 QUARTERLY GROUNDWATER SAMPLING -APRIL 1991 <br /> On April 25, 1991, Ms. Hinson requested one additional quarterly water sampling of <br /> monitoring well MW-3B before she would recommend site closure to the Regional <br /> Water Quality Control Board. <br /> On May 2, 1991, Clayton conducted the additional quart--rly water sampling of <br /> monitoring well MW-3B. This task was conducted to assess groundwater for possible <br /> contamination from the hydrocarbons detected in the surrounding soils. <br /> The groundwater sample was analyzed by the following methods: <br /> • EPA Method 503018015-8020, for gasoline and BTEX <br /> EPA Method 351018015, for TPH as diesel fuel <br /> ' i <br /> EPA Method 418.1, for TRPH <br /> a Standard Method 5520F, for TPH <br /> ' 4 <br /> Analytical results revealed gasoline, BTEX, diesel, TPH, and TRPH were below <br /> ~— detection levels. <br /> 6.4 ADDITIONAL SOIL INVESTIGATION CONCLUSIONS <br /> The oil and grease, diesel, and hydrocarbons that were detected in MW-3B at 4 feet <br /> i bgs were not detected in the soil samples taken from any of the five boreholes. These <br /> constituents do not leach easily from soils, and analysis of groundwater samples from <br /> { y MW-3B did not reveal detectable concentrations. Based on the limited extent of the <br /> constituents demonstrated by analysis of soil samples from the surrounding boreholes, <br /> Clayton recommended no further soil remediation at the subject site. Moreover, in a <br /> letter to the RWQCB dated July 16, 1991, the SJC/EHD recommended site closure, <br /> corroborating with Clayton. <br /> -; Orchard Supply Hardware requested that SJC/EHD recommend site closure to the <br /> RWQCB. The letter from SJC/EHD to the RWQCB recommending site closure is <br /> P <br /> in Appendix B. <br /> +w <br /> I <br /> 70 REFERENCES <br /> Leaking Underground Fuel Tank (LUFT) Field Manual: Guidelines,for Site <br /> Assessment, Cleanup, and Underground Tank Closure, May 1988. State of California <br /> i LUFT Task Force: <br /> �..f <br /> Mar shack, J.B., 1990. :A Compilation of Water Quality Goals, Staff Report of the <br /> California RWQCB Central.Valley Region. <br /> Regional Board Staff Recommendations for Initial Evaluation and Investigation of <br /> Underground Tanks, Revised November 1989. North Coast, San Francisco Bay, and <br /> Central Valley regions of the California State Water Quality Control Board <br /> 11 <br />