WORK PLANS_FILE 2 - Laserfiche WebLink

Home Browse Search

1... `� v •..sour OVA www.atcassociates.com Groundwater samples were analyzed for selected constituents (see Table 3). MTBE was the �. only groundwater constituent reported above the laboratory reporting limit in samples collected from monitor wells MW-1 R, MW-2 and MW-5. Groundwater constituents analyzed were not reported in monitor wells MW-4 and MWA 1. ` `r The September 2010 groundwater analytical results for monitor wells MWA R, MW-2 and MW-5 are presented below and compared to the Regional Water Quality Control Board Region 2 Environmental Screening Levels-2005, updated 2008 (ESL), California Environmental �- Protection Agency (CaIEPA) California Human Health Screening Levels-2005 (CHHSL) and CaIEPA Maximum Contaminant Levels-2008 (MCL). As shown below groundwater constituents reported are below respective ESL, CHHSL and MCL concentrations. GROUNDWATER CONCENTRATIONS (reported in lig/L ESL CHHSL MCL MW-1R MW-2 MW-5 '-' TPHg 210 - 50 <50 <50 Benzene 46 5.0 1.0 <0.50 - Toluene 130 1,000 150 <0.50 ` Eth (benzene 43 i 700 300 <0.50 Total Xylenes 100 10,000 1,750 -- <1.0 -- MTBE 1,800 - 5.0 0.55 3.8 2.3 TAME - - - -- -- <0.50 - �.. TBA 18,000 <4.0 � ETBE - - (1): source=Table F-1b: Groundwater Screening levels(groundwater is not a current or potential drinking water resource) �. L/ ' TBA-tert butyl alcohol ETBE-ethyl tert butyl ether Soil samples were collected from borings SB-4, SB-5 and MW-11 at a depth of 12 feet bgs to evaluate subsurface conditions. Soil samples were analyzed for selected constituents (see Table 1). Soil sample laboratory results from the January 2010 Additional Investigation Report are presented below. Soil sample analytical results are compared to the ESL, CHHSL and the United States Environmental Protection Agency- Region 9 Primary Remediation Goals (PRG). As shown below soil constituents reported are below respective ESL, CHHSL and PRG concentrations. V SOIL CONCENTRATIONS (reported in m /k ESIJ21 CHHSL PRG SB-4-12 SB-5-12 MW-11-12 TPH9 180 - - Z 0 -40' 7'x22 4/6.2t- <- Benzene 2.0 0.64 1.1 0.0049 <0.0044 - <0.0045 inCo+' Toluene 9.3 520 5,000 <0.0043 <0.0044 - <0.0045 Eth (benzene 4.7 400 5.4 0.0073 <0.0044 - <0.0045 Total Xylenes 11 270 630 <0.0086 ' <0.0088 - <0.0090 MTBE 8.4 32 43 <0.0043 <0.0044 - <0.0045 DIPE - - 1,400 <0.0043 <0.0044 <0.0045 TAME - - - <0.0043 <0.0044 <0.0045 TBA 110 6,100 - <0.0086 <0.0088 <0.0084 ETBE - - - <0.0043 <0.0044 <0.0045 (2): source=Table D-1: Deep Soil Screening levels(>3m bgs)Residential Land Use(groundwater is not a current or potential drinking water resource) DIPE-diisopropyl ether Quik Stop Market No. 132 July 21, 2011 ATC Project Number 75.62503.3206 Page 3 of 5