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1 <br /> r' <br /> Thirdarter 1993 Groundwater Monitore ort A ���� <br /> Qu n$Report <br /> Tri-Valley Growers,Thornton,California <br /> Project No 152102 02 <br /> Page 2 <br /> Samples were analyzed for benzene, toluene, ethylbenzene, and xylenes (BTEX) and total <br /> petroleum hydrocarbons as gasoline (TPHg), by EPA methods 8020 and modified 8015, <br /> respectively <br /> ANALYTICAL RESULTS <br /> The sample from MW1 was reported to contain 80 parts per billion TPHg, however, the <br /> laboratory reported that this was a non-gasoline mixture No dissolved gasoline hydrocarbon <br /> constituents were reported at or above detection limits in monitoring wells MW2, MW3, MW5, <br /> or MW6 No analytes were detected in the water sample from the domestic well (LRW) on the <br /> neighboring site. <br /> Influent and effluent samples from the pumping well (MW4) were collected for analysis of <br /> BTEX and TPHg on September 9, 1993 Analytical results indicate a slight increase in TPHg <br /> and BTEX concentrations in the influent sample collected during this sampling round The <br /> samples collected from carbon filter 1 (TVGT EFF 1 C) and carbon filter 2 (TVGT EFF2C) did <br />. not contain any detectable analytes Influent BTEX and TPHg concentrations over time are <br /> plotted on Figures 5 and 6 <br /> Laboratory analyses were performed by Sequoia Analytical Laboratory (ELAP No 1210) The <br /> analytical results are summanzed In Table 2, the laboratory reports and chain of custody <br /> documentation are presented in Attachment B <br /> REMEDIATION SYSTEM PERFORMANCE <br /> Overall, analytical results support the effectiveness of the system Historical sampling results <br /> show fluctuating influent hydrocarbon concentrations which may be attributed to fluctuating <br /> water table elevations However, for the most part, laboratory results indicate that influent <br /> TPHg and BTEX concentrations have been significantly reduced since system start-up <br /> RESNA personnel will continue with the quarterly monitoring program which will include <br /> reports detailing system performance. We will continue to monitor system performance and <br /> adjust pumping rates as necessary <br /> 3QR-1993 FNL <br />