ARCHIVED REPORTS_XR0009109 - Laserfiche WebLink

Home Browse Search

Groundwater samples were collected from the five monitor wells on November 19, 1992 and submitted for laboratory analysis. The analytical results indicated that no detectable concentrations of TPH were present in the groundwater samples collected from the five monitor wells at the site Concentrations of benzene were detected in groundwater samples collected from monitor wells MW2, MW3 and MW4 at 0.58 micrograms per liter (µg11), 7.7 1Ag1l and 18 µg/l, respectively. Toluene and ethylbenzene were detected only in the groundwater sample collected from well MW4 at a concentration of 1.2 µg11, respectively. Xylenes were detected ' in groundwater samples collected from MW3 and MW4 at concentrations of 1 2 µg11 and 13.5 µg11, respectively. ' This report presents the results of the June 1993 quarterly groundwater monitoring event conducted at the property, the second groundwater sampling event performed at the property. This work was conducted in accordance with the State Water Resources Control Board Leaking Underground Fuel Tank (LUFT) and Regional Water Quality Control Board (RWQCB) guidelines for the preliminary evaluation and investigation of underground tank sites Groundwater samples were not collected following the November 1992 sampling event until June 1993 Quarterly sampling will now continue at three month intervals (i.e., September, December) 2.0 WATER LEVEL MEAS S Water surface elevation data were obtained from the monitoring wells at the subject site on June 4, 1993 Water surface elevation data are presented in Table 1. Contours of equal water surface elevation developed from the data are presented in the Potentiometric Surface Map included as Figure 2 Sample event data sheets are included as Appendix I. Groundwater elevations measured June 4, 1993 were approximately four feet higher than when last measured on November 12, 1992 Groundwater at the site on June 4, 1993 was determined to flow to the northeast. 3.0 WATER QUALITY SAMPLING AND ANALYSIS 1 Groundwater samples were collected from the five monitoring wells located at the property on June 4, 1993 All groundwater samples were analyzed for total petroleum hydrocarbons (TPH) using DHS LUFT (EPA Method 8015 Modified), for benzene, toluene, ethylbenzene, and xylenes (BTEX) easing EPA Method 602 and for total lead using EPA Method 7421. Following the purging of at least three casing-volumes of groundwater from the well using a peristaltic pump, samples were collected using a clean disposable bailer The groundwater was decanted and sealed in laboratory provided containers, labelled, placed into plastic zipper-lock bags and placed in a cooler containing ice The samples and one trip blank were delivered under moa1oai 3