ARCHIVED REPORTS_XR0013098 - Laserfiche WebLink

Home Browse Search

Fuller Mobile Home Park 363 E. Louise Ave-, Lathrop, California January 28, 1998 Eastern Soil Contaminatin Boundary and Confirmation Work Plan Page: 2 ND (None Detected), but the groundwater sample had BTEX contamination. B-6 was ND for both soil and water. Monitoring well MW-4 was installed in the sidewalk of Bizzibe Street in the apparent down-gradient direction. Laboratory soil samples were obtained at five, ten and twenty-five feet below ground level (Tables 1 & 2). On December 21, 1994, after receiving the analytical results from the previous borings, WHF drilled and installed three monitoring wells, MW-5, 6 and 7. Each was 25 feet deep and soil samples were taken at five and ten feet. All soil samples tested "ND" (Table 1). Monthly depth to water readings are being recorded and the groundwater gradient calculated for each month. The past gradients have been irregular, probably due to the fact that the gradient is extremely flat and the lithology is probably affecting stabilization of the minor fluctuations across the site (Appendix A). 3.0 Scope of Work Eastern Boundary Confirmation A single slant hand auger boring will be accomplished at the east boundary ry ofth e property in the area of the former UST location. The boring will be advanced on a 30° angle to accomplish a vertical depth of 15.0 below grade level (bgl). Soil samples will be collected every five (5) foot for laboratory analysis. Since this is a sampling exercise, no boring logs will be completed. The site has already been well characterized geologically (Figure 3). Confirmation Borings Four (4) hand auger borings will be completed in the formerly explored areas around borings B-1, B-2, B-3 and B-4 as shown on Figure 3 of this Work Plan. The hand borings will be advanced to -12.5 bgl of the former surface grade. This is due to the construction of a storm retention pond in 1993. Again no boring log will be completed as this is a confirmation exercise to identify petroleum hydrocarbon contamination remaining around the previously investigated area. A single soil sample will be collected at the termination of each hand boring. 3.1 Drilling The soil borings will be accomplished using a hand auger to accomplish the shallow sampling borings. All drilling equipment will be thoroughly cleaned before drilling begins, to prevent { the introduction of contamination from off site, and between borings to prevent L cross contamination.