ARCHIVED REPORTS_XR0010834 - Laserfiche WebLink

Home Browse Search

KLEINFELDER 1 EXECUTIVE SUMMARY I i This is "a report .of Kleinfelder's second quarter 2003 groundwater monitoring for the former Disco Facility located at 110 North Filbert Street in Stockton, California. On May 15, 2003, twenty monitoring wells and three piezometers were sounded for depth to groundwater. On May 16, and 19, 2003, seven monitoring wells were sampled by Kleinfelder. The monitoring wells sampled were MW-DIS-1 ls, MW-DIS-I ld, MW-DIS-12, MW-DIS-13, MW-DIS-14s, MW-DIS-14d, and MW-DIS-15. The monitoring wells were sampled in accordance with the "Groundwater Monitoring Frequency Decision Tree" developed by CH2M Hill. i The depth to groundwater ranged from 42.51 feet below the top of the well casing (MW-DIS- E lls) to 51.74 feet below the top of the well casing (MW-DIS-15). Groundwater elevations for the monitoring wells ranged from —31.42 feet (MW-DIS-6) to —32.30 feet (MW-DIS-13). Groundwater flow direction at the site is estimated to be towards the east/southeast at approximately 0.0006 ft./ft. The Tgroundwater samples were analyzed for the following: benzene, toluene, ethylbenzene, and total xylenes (BTEX), Total Petroleum Hydrocarbon as gasoline (TPH-g), 1,2-Dichloroethane (1,2-DCA), 1,2-Dibromoethane (EDB), and tert-Butyl Alcohol (TBA). Only one groundwater sample (MW-DIS-15) was additionally analyzed for all of the oxygenates Di-isopropyl Ether (DIPE), Ethyl t-Butyl Ether (ETBE), Methyl tert-Butyl Ether (MTBE), and tert-Amyl Methyl Ether (TAME). MW-DIS-14s was additionally analyzed�for MTBE. This was the second groundwater sampling event conducted from MW-DIS-15 since it was installed in February 2003. There was no TPH-g detected in the seven groundwater samples analyzed, at or above the laboratory reporting limit of 50 µg11. Similarly, no BTEX compounds were detected in the groundwater samples collected. 1,2-DCA was detected in 4 of the 7 groundwater samples. The detected concentrations ranged from 0.53 µg/1 (MW-DIS-1ld) to 110 4g/1 (MW-DIS-1ls). It should be noted that the detection of 1, 2-DCA in MW-DIS-11d marks the first time 1, 2-DCA has been detected in MW-DIS-1 Id. _The detected concentration of 0.53 µg/l was just above the laboratory reporting- limit of 0.50 ` µg11. The detected concentrations of 1,2-DCA exceeded the Primary Maximum Contaminant t Level (PMCL) for 1,2-DCA of 5 µg/l in'2 of the samples. There were no detectable concentrations at or above the laboratory reporting limit for the oxygenates MTBE, DIPS, ETBE, and TAME in the groundwater sample collected from MW- DIS-15. However, MTBE was detected in MW-DIS-14s with a concentration of 0.78 µg/1. The Primary Maximum Contaminant Level (PMCL) for MTBE is 13 µg11 and the Secondary 12280.MON/ST03R897 Page l of 12 0 2003,Kleinfelder,Inc July 1,2003 o