ARCHIVED REPORTS_XR0004181 - Laserfiche WebLink

Home Browse Search

. Mr Kyle Christie Project 0805-144 02 January 24, 1996 Page 2 collecting groundwater samples for subjective and laboratory analyses EMCON used these data to evaluate the gradient and direction of groundwater flow beneath the site On November 15, 1995, a technician from EMCON took water level measurements and collected groundwater samples from monitoring wells MW-I through MW-4 for subjective and laboratory analyses The technician did not observe floating product or product sheen on samples collected from the wells (see Table 1) Sampling and analysis procedures are presented in Appendix A The surveyed elevations of the top of casing and the depth-to-groundwater measurements (see Table 1) were used to evaluate the potentiometnc surface beneath the site On November 15, 1995, the direction of groundwater flow was toward the northwest with a gradient of approximately 0 02 (see Figure 3) The direction of groundwater flow is consistent with previous sampling events Groundwater elevation increased approximately 0 28 foot from the previous sampling event (August 1995) Groundwater samples from each well were analyzed for total petroleum hydrocarbons as gasoline (TPHG), and benzene, toluene, ethylbenzene, and total xylenes (BTEX) using • California Department of Health Services LUFT Method and Environmental Protection Agency Method 5030/8020, respectively The samples were analyzed at Columbia Analytical Services, Inc , in San Jose, California The results of analyses are summarized in Table 1 Copies of the chain-of-custody records and laboratory analysis reports are presented in Appendix B Results of analyses indicated TPHG and BTEX concentrations were below laboratory detection limits in groundwater samples collected from wells MW-1 through MW-4 ACTIVITIES PERFORMED DURING THE FOURTH QUARTER • EMCON performed quarterly groundwater sampling • EMCON compiled and evaluated groundwater monitoring data ANTICIPATED WORK • ARCO will continue to perform quarterly groundwater monitoring The next sampling event is tentatively scheduled for February 1996 . CONCLUSIONS The groundwater flow direction was to the northwest, which is consistent with previous sampling events. Gasoline hydrocarbons were not detected in groundwater samples collected from monitoring wells MW-1 through MW-4 Gasoline hydrocarbons have not SACNN SPRM805\08051440 2DS-9 ftu 1