ARCHIVED REPORTS_XR0005740 - Laserfiche WebLink

Home Browse Search

i DISCUSSION: Total petroleum hydrocarbons as gasoline(TPHg) were reported in four of the six monitoring wells sampled this quarter at concentrations ranging from 120 ppb (MW-3)to 2,100 ppb(MW-1) Benzene was reported in four of the six monitoring wells at a concentrations ranging from 0 52 ppb(MW-3)to 94 ppb(MW-1) Methyl tert-butyl ether (MtBE),analyzed using EPA Method 8260B,was detected in five of the six monitoring wells at concentrations ranging from 19 ppb(MW-1)to 670 ppb(MW4) 1,2-dichloroethane(1,2-DCA)was reported in five of the six monitoring wells at concentrations ranging from 10 ppb(MW-1)to 150 ppb(MW4) Additionally,domestic well WSW and well DW-2 were sampled for TPHg,benzene,toluene,ethylbenzene,and total xylenes(BTEX),MtBE,and fuel oxygenates, all of which were reported as nondetectable above the method reporting limits Chemical concentrations were generally consistent with historical data,except for a decrease in concentrations m MW-4 Groundwater flow was linearly inward at an approximate gradient of 0 001 ft/ft, which is generally not consistent with historical data Groundwater elevations across the site increased by an average of 0 14 ft SECOR is performing granulated activated carbon treatment on well DW-1 Influent and effluent water samples are taken monthly and reported under separate cover in monthly performance summaries DW-2 and the onsite water supply well(WSW)are incorporated into the quarterly monitoring and reporting Data from DW-2 is included in tables 4 and 5 Certified laboratory analytical data is included in Attachment B iThis 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 ATTACHMENTS: • Table 1—Groundwater Elevation and Analytical Data • Table 2—FueI Oxygenates Analytical Data • Table 3 -Groundwater Gradient Data • Table 4--Domestic Well Analytical Data • Table 5—Domestic Well Fuel Oxygenates and Nitrate/Nitrite Analytical Data • Figure 1 -Groundwater Elevation Contour Map • Figure 2-Groundwater Concentration Map • Attachment A-Field and Laboratory Procedures • Attachment B -Certified Laboratory Analytical Reports,Chain-of-Custody Documentation,and Field Data Sheets cc Mr Marty Hartzell,Regional Water Quality Control Board-Central Valley Region(RWQCB-CVR) Ms Lori Duncan,SJCPHS Ms Madeline Scannavino,5463 Cherokee Rd,Stockton,CA 95205