Laserfiche WebLink
3 GROUNDWATER MONITORING RESULTS <br /> IGroundwater elevation data and analytical results are discussed in this section <br /> Laboratory analytical reports are contained in Appendix B <br /> r <br /> 3.1 Groundwater Elevation Data <br /> IGroundwater elevations measured in site monitoring wells on April 26, 2002 <br /> (summarized in Table 1), ranged from minus (-) 22 97 feet to--- 23 91 feet <br /> MSL Groundwater levels in the wells increased approximately 0 3 from the <br /> previous January 2002 monitoring event As shown in Figure 3, the <br /> groundwater flow direction is easterly at a gradient of about 3 2 x 10"3 feet per <br /> ' foot, which is consistent with historic trends <br /> 3.2 BTEX and TPH-G Analytical Results <br /> Since the installation of new sparging well SP-A, petroleum hydrocarbon <br /> ' concentrations in groundwater samples have significantly decreased As <br /> shown in Table 4,petroleum concentrations in groundwater samples collected <br /> this quarter from most of the more highly impacted wells (MW-1, SP-1, PZ-1) <br /> have typically dropped by a factor of about 10 compared to the previous <br /> quarter <br /> ' BTEX and TPH-G compounds were detected in groundwater samples <br /> collected from wells MW-1, MW-12, SP-1, SP-2, PZ-1, and PZ-2 There were <br /> no detectable petroleum hydrocarbon concentrations measured in samples <br /> ' from wells MW-4, MW-9, MW-10 and MW-13 <br /> The highest BTEX concentrations still appear to be centered in the vicinit oif <br /> ' the former gasoline USTs near wells MW-1, SP-1, SP-2 and PZ- see a�sm Qypti <br /> Figure 4) Detected benzene concentrations ranged from 18 µg/l in the sample 1�1y I <br /> collected from well MW-1 to 620 µg/1 in the sample from SP-1 Toluene <br /> ranged from 1 5 µg/1 in the sample from SP-2 to 320 µg/l in the sample from <br /> PZ-2 Ethylbenzene ranged from 5 5 pg/l in the sample from MW-1 to <br /> 310 µg/l in the sample from PZ-2 Xylenes ranged from 10 µg/l in the sample <br /> from SP-2 to 1,500 µg/l in the sample from PZ-2 <br /> Higher TPH-G concentrations are similarly centered near the former gasoline <br />' USTs (Figure 5) TPH-G concentrations were measured in the MW-1, <br /> 9 <br /> . April 2002 <br /> � Groundwater Monitoring And <br />' Air Spargmg Well Installation Report <br /> The Earthgrams Baking Company <br /> 2651 South Airport Way <br /> Stockton,CaliforniaPrepared for THE EARTHGRAINS BAKING COMPANY Prepared by Philip Services Corp <br /> H\ENV1624001321I21382EG\StocktonlStocktonW402mon doc May 21,2002 <br />