ARCHIVED REPORTS XR0000399 - Laserfiche WebLink

Home Browse Search

S E C O R Ms Lori Duncan April 18, 2003 Page 2 DISCUSSION (ARCO): On March 18 and 19, 2003, SECOR International Incorporated (SECOR) conducted groundwater monitoring and sampling for the 151 quarter 2003 ARCO station 2133, in conjunction with Gettler-Ryan (G-R) performing groundwater monitoring and sampling for Chevron service station 9-4275 Nineteen ARCO wells were sampled during this event Groundwater samples were analyzed for total petrofeum hydrocarbons quantified as gasoline (TPHg), benzene, toluene, ethylbenzene, and xylenes (BTEX), and the fuel oxygenate methyl-tertiary-butyl-ether (MtBE) TPHg were reported in 2 of the 19 wells sampled this quarter at concentrations of 69 µg/L (BHD-1) and 1,100 µg/L (E-10) Benzene was reported in 1 of the 19 wells at a concentration of 6 5 µg/L (E-10) MtBE was reported in 2 of the 19 wells at concentrations of 97 gg/L (BHD-1) to 1,300 ug/L (E-10) Groundwater elevations across the site increased by an average of 0 17 ft DISCUSSION (CHEVRON): Nine Chevron wells were sampled during this event Groundwater samples were analyzed for TPHg, BTEX, and the fuel oxygenates MtBE, ethyl-tertiary- butyl-ether (EtBE), di-isopropyl ether (DIPE), tertiary-amyl-methyl-ether (TAME), ternary-butyl-alcohol (TBA), 1,2 dichloroethane (1,2 DCA) and 1,2 dibromoethane (EDB) Toluene, TBA, DIPS, ETBE, 1,2- DCA, and EDB were not detected in samples from any of the wells TPHg was detected in four wells at concentrations ranging from 83 pg/L in the sample collected from MW-6 to 1,700 µg/L in the sample collected from MW-2 Benzene was detected in two of the nine wells at concentrations of 18 lag/L in the sample collected from MW-4 and 2 µg/L in the sample collected from MW-2 MtBE was detected in six wells at concentrations ranging from 7 µg/L in the sample collected from MW-5 to 3,300 1Lg/L in the sample collected from MW-1 Ethyl benzene was detected in two wells at concentrations of 0 9 µg/I in the sample collected from MW-5 and 3 pg/1 in the sampled collected from MW-2 Xylenes were detected in one well at a concentration of 11 µg/l in the sample collected in MW-2 Ethyfbenzene was detected in one well at a concentration of 6 pg/l in the sample collected in MW-2 TAME was detected in three wells at concentrations ranging from 2 pg/L in the sample collected from MW-2 and 35 gg/L in the sample collected from MW-1 Groundwater flow across both sites was to the north at an approximately gradient of 0 002 foot per foot (ft/ft), which is generally consistent with historical data ARCO's groundwater elevation and analytical data are summanzed in Table 1 Chevron's groundwater elevation and analytical data are summarized in Tables 2 and 3 Table 4 presents historical groundwater gradient data A groundwater elevation contour map of the two sites is presented as Figure 2 Groundwater concentrations for both sites are summarized for TPHg, benzene, and MtBE in Figure 3 Attachment 1 contains ARCO's historical SVE and recent AS system operational data Attachment 2 contains field and laboratory procedures Attachment 3 contains ARCO laboratory analytical results, chain-of-custody documentation, and field data sheets Attachment 4 contains Chevron laboratory analytical results, chain-of-custody documentation, and field data sheets This report presents our understanding of existing conditions at the subject site The conclusions contained herein are based on the analytical results, and professional judgment in accordance with current standards of professional practice, no other warranty is expressed or implied SECOR assumes no responsibility for exploratory borings or data reported by other consultants or contractors