ARCHIVED REPORTS XR0001405 - Laserfiche WebLink

Home Browse Search

Page 3 Mr Michael Iinfuma Jr, Senior REHS August 13,2001 pH, and electrical conductivity parameters were also measured during the purging ' process to assess groundwater stability Purged groundwater was placed in one 55-gallon drum, which was temporarily stored on-site pending proper disposal ' Groundwater samples were collected from each well with its own dedicated bailer Samples were placed in clean, laboratory-provided glass containers, sealed, ' labeled, and stored in an insulated iced chest Samples were delivered to Acculabs, Inc laboratory in Davis, California, accompanied by chain-of-custody documentation, for chemical analysis Samples were analyzed for BTEX and TPHg compounds using EPA Method 602/8015 Samples were also analyzed for oxygenate compounds tert-butanol (TBA), methyl-tert-butyl ether (MTBE), di-isopropyl ether (DIPS), ethyl-tert-butyl ether (ETBE), and tert-amylmethyl ether (TAME) using EPA Method 8260B Groundwater Level Measurements As shown in Table 1 (Attachment 2), groundwater within the monitoring wells were measured at depths approximately 1 feet lower than the previous round of monitoring performed in April 2001 Groundwater depths ranged from 24 42 feet (below the top of the well casing)to 25 00 feet The corresponding groundwater elevations, evaluated during this monitoring period, ranged from minus (-)13 42 feet to —13 73 feet relative to mean sea level As shown in Figure 3, groundwater flows easterly at an approximate gradient of 3 45 x 10-3 feet per foot, which is consistent with historic trends Groundwater Sample Analytical Results ' Petroleum hydrocarbon concentrations were non detect n y ed i the sample from monitoring well MW-1 Relatively low concentrations of toluene and xylenes were measured in the sample from well MW-3 Higher petroleum hydrocarbon concentrations were measured in the groundwater sample collected from monitoring well MW-2 (see Table 2) Petroleum hydrocarbon concentrations in the current MW-2 groundwater sample are generally lower, but still within an order of magnitude, compared to the initial sample collected from this well in July 1999 Benzene and TPH-g concentrations in the current MW-2 sample were measured at 13,000 micrograms per liter (ug/1) and 91,000 ug/l, respectively (see Figure 4 and Figure 5)