Laserfiche WebLink
k <br /> Former Discovery Chevrolet I <br /> September 26, 1995 <br /> Quarterly monitoring and sampling of the monitoring wells begin in March 1995. <br /> Historically, depth to groundwater has fluctuated between 9.95 and 11.53 feet bgs. <br /> Groundwater appears to flow toward the north-northwest at a gradient of approximately <br /> 0.003. Floating product has not been observed in the monitoring wells. Petroleum <br /> hydrocarbons have not been detected in well MW-3. TPHg concentrations in wells MW-1 <br /> and MW-2 have ranged from 60 to 7,600 ppb, and benzene concentrations have ranged from <br /> 10 to 730 ppb. Quarterly groundwater monitoring and sampling data are summarized in <br /> Table 1. <br /> PRESENT QUARTER FIELD ACTIVITIES <br /> Quarterly monitoring and sampling of the groundwater monitoring wells for the third quarter <br /> 1995 was performed by G-R on August 8, 1995. Field monitoring and chemical analytical ` <br /> data from the current quarter are summarized in Table 1. The G-R groundwater sampling <br /> procedures are summarized in Appendix A. Copies of the G-R field data sheets are <br /> presented in Appendix B. Copies of the laboratory analytical report and completed chain-of- F <br /> custody form are presented in Appendix C. <br /> Groundwater Monitoring and Gradient Evaluation <br /> Depth-to-water (DTW) measurements were obtained by G-R from groundwater monitoring <br /> wells MW-1 through MW-3 prior to well purging and sample collection. Static groundwater <br /> levels were measured from the north edge of the top of each well casing and recorded to the <br /> nearest ±0.01 foot. Groundwater was measured between 10.89 and 11.53 feet bgs. These <br /> water-level data were used to construct a Potentiometric Map (Figure 3). Based on these <br /> data, the shallow groundwater beneath the subject site appears to flow toward the south- <br /> southeast at a gradient of approximately 0.003. Each well was inspected for the presence <br /> of floating product. Floating product or a product sheen was not observed in any of the <br /> groundwater monitoring wells this quarter. <br /> Laboratory Analytical Data <br /> The groundwater samples were collected in sample containers supplied by the laboratory. <br /> The samples from well MW-1 through MW-3 were analyzed for TPHg by Environmental <br /> Protection Agency (EPA) Method 5030/GC-FID, and for benzene, toluene, ethylbenzene, <br /> and total xylenes (BTEX) by EPA. Method 8020. The sample from well MW-3 was also <br /> analyzed for TPHd by EPA Method 5030/GC-FID, and for Oil and Grease (O&G) by <br /> Standard Method 5520BF. The samples were analyzed by American Environmental Network <br /> (ELAP #1172) located in Pleasant Hill, California. <br /> TPHg and benzene were detected in wells MW-1 (1,400 and 250 ppb, respectively) and. <br /> MW-2 (60 and 10 ppm, respectively). TPHg, BTEX, TPHd, and O&G were not detected <br /> 8146.02-3 3 <br /> i�. <br /> I. <br /> C <br /> C <br />