Laserfiche WebLink
1 <br /> 4.0 Fourth Quarter Groundwater Monitoring and Sampling <br /> ' 4.9 Monitoring <br /> The fourth quarter 1994 groundwater monitoring data were collected on <br /> November 14, 1994 Monitoring activities included measuring the groundwater <br /> ' elevation in nine onsite monitoring wells shown on Figure 4-1 Groundwater <br /> ' measurements were taken using an electronic oil/water interface probe. Free <br /> product was not detected in any of the onsite monitoring wells Depth to <br /> groundwater and well depth measurements were recorded for each monitoring well <br /> 1 and are listed in Table 1 Data collected were used to determine groundwater flow <br /> direction and gradient as shown on Figure 4-2 The general groundwater flow <br /> ' direction is to the southwest which is consistent with previous quarterly monitoring <br /> events. Waste Science will continue to monitor the groundwater flow direction and <br /> ' gradient during subsequent quarterly monitoring events <br /> 4.2 Sampling <br /> Field groundwater monitoring data(conductivity,pH, temperature,and turbidity) <br /> and groundwater elevation data were used to determine the volume of purge water <br /> to be removed from each monitoring well prior to sampling Samples were collected <br /> after physical parameters stabilized and a minimum of three well volumes of water <br /> ' had been removed Purge water and other investigation-denved wastes (IDW) were <br /> placed in Department of Transportation (DOT) approved 17E/H drums <br /> IDW will be sampled and submitted to the District's laboratory for waste <br /> ' characterization as specified in the July 1993 Additional Assessment and Groundwater <br /> Monitoring Work Plan (Work Plan) Upon receipt of the waste profile <br /> ' characterization results, the IDW will be disposed of appropriately <br /> Groundwater samples were collected using Teflon bailers on November 14, 1994, <br /> ' from three of the nine monitoring wells (MW-1, MW-8, and MW-9) One sample <br /> from each well was collected and submitted for analysis by United States <br /> Environmental Protection Agency (USEPA) Method 8020 for benzene, toluene, <br /> ' ethylbenzene, xylenes (BTEX), and Method 8015 Modified for TPH-g All samples <br /> were submitted to the District's State certified laboratory along with the appropriate <br /> ' Chain-of-Custody forms <br /> Quality control samples were collected to provide a check on the sampling, <br /> analysis, and shipping procedures One duplicate sample was collected from MW-8 <br /> ' 95R2 East Bay Municipal Utility District <br /> 40429600\4thgtr gw 3 Stockton 5erme Center-Fourth Quarter 1994 <br />