Laserfiche WebLink
Canteen Facility August 31, 2000 <br /> Quarterly Groundwater Monitoring Report Page 3 <br />. Groundwater Gradient <br /> Interpretation of the monitor well gauging data indicates that there is a southerly hydraulic <br /> gradient across the Site of approximately 0 007 feet/foot Figure 2 presents the <br /> groundwater gradient map for this gauging event The gradient appears to be consistent <br /> with past gauging events <br /> Groundwater Analytical Results — Contaminant Concentrations <br /> Groundwater quality data are compared to the California Department of Health Services <br /> Drinking Water Standard Maximum Contaminant Levels (CAMCL) Analysis of the <br /> seventeen groundwater samples obtained from the on-Site monitor wells indicated the <br /> following <br /> • Benzene was detected in groundwater samples from monitor wells MW3, MW3A, <br /> MW3B, MW10, MW13, MW13A and MW13B at concentrations ranging from 0 8 <br /> to 11,000 µg/1 The CAMCL for benzene is 1 0 µg/1 The concentrations in MW- <br /> 3 have increased since June 1999 However, the concentrations in MW-13 have <br /> decreased since the last sampling event conducted in June 1999 <br /> • Toluene was detected in monitor well MW3, MW 12, MW13, MW13A and <br />. MW13B at concentrations ranging from 0 9 to 21,000 µg/1 The CAMCL for <br /> toluene is 150 µg/1 Concentrations of toluene are generally decreasing in the Site <br /> monitor wells <br /> • Ethylbenzene was detected in monitor wells MW3, MW3D, MW13 and MW13A <br /> at concentrations ranging from 2 2 to 2,200 µg/1 The CAMCL for ethylbenzene is <br /> 700 µg/1 Only one groundwater sample, MW-13, exceeded the CAMCL for <br /> ethylbenzene <br /> • Xylenes were detected in monitor wells MW3, MW3 A, MW3B, MW13, MW13A, <br /> and MW13B at concentrations ranging from 0 9 to 13,000 µg/1 The CAMCL for <br /> xylenes is 1,750 µg/L Only one groundwater sample, MW-13, exceeded the <br /> CAMCL for xylenes <br /> • TPH(g) was detected in monitor wells MW3, NMA, MW3B, MW13, MW13A <br /> and MW 13B at concentrations ranging from 64 to 87,000 µg/1 <br /> Groundwater analytical data are summarized on Table 2 A map depicting benzene <br /> concentrations in each of the on-Site monitor wells is provided in Figure 3 <br />