SITE INFORMATION AND CORRESPONDENCE FILE 2

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aw I —�Xr0 - - CLEARWATER C4 5t 0 U R. I 1 N. C, ' #pptoximatey rin-iSi of tfLe... to north of the site. [A domestic water Drell. is located In the approly 2 240 feet wall was installed in approximately 1987 and is screened from 165 -to 185 feet be,low gxade. The bentonite sanitary seal for the well extends to a depth of 100 feet below grade. Water from the well is currently not used for drinking, although it is used: for bathing and rather domestic sanitary purposes. Water samples collected.frim it have historically beer► free of detectable levels of gasoline hydrocarbons. - _. The building on-site is currently used as the Ruiz Grocery Store, and was used in the past as a gasoline station. The gasoline station operated two 1.000-gallon underground storage tanks (UM),, plumbed to one dispenser island. Both unleaded axed leaded gasoline were stored in the USTs. The USTs were removed in Rbruary 1988. 2:3 Previous Investigations In date 1991, Delta Environmental Consultants supervised the installation of three zrionitoring wells (MW-1 through MW-3). Groundwater was present at a depth of approximately 10 feet below grade,..and flow was toward the northeast. Separate phase hydrocarbons (SPH) have been detected intermittently in wells MW-1 and MW-Z; however, water samples collected from well MW-3 and the domestic well were free of gasoline hydrocarbons. Between October 1943 and July 1994, RESNA Industries Inc. (RESNA) supervised the drilling of six soil borings (HP-1 through HP-6), and the installation of four additional monitoring wells (MW-4 through MW-7) and three vapor wells (VW-1 through VW-3). Sediments encountered beneath. the site consisted primarily of interbedded silts and silty sands with lesser amounts of isolated clay beds to a depth " of 26.5 feet below grade, the maximum depth explored, Groundwater was present.at a depth of approximately 12 feet below grade and flow was toward the northwest. Soil samples collected from perimeter borings (HP-1 through HP-6 and MW-4 through MW-7) did not contain detectable levels of gasoline hydrocarbons, and thus delineated the vertical and horizontal extent of vadose zone ,contamination, dater samples collected froin the new wells were also free of detectable levels of gasoline hydrdearbons, and therefore also delineated. the extent of contamination in the shallow water bearing zone. Both soil and groundwater contamination appeared to be centered within an approximate 60,foot radius of the former UST pits. Results of this phase of investigation were presented in RESNA's summary letter report dated September 2, 1.994, Groundwater has historically fluctuated between 10 and 17 feet below grade, and flow Lhas varied from the: northwest' to northeast at hydraulic gradients from. approximately 0.001 to 0.004, ❑-107, PAR/RAP 2 February 21, 1996 r I a 30tid LV6S66Ki5:i VzI dMd0 ZJ310 l d3l"03-10:QI 9.P;01 WV 00, 3T-W MW ON :1114