Laserfiche WebLink
. a <br /> "RI WOW <br /> f <br /> Third-Quarter Groundwater Monitoring Letter Report October 18, 1991 <br /> Tri-Valley Growers, Thornton, California 2102 <br /> ` Samples were analyzed for benzene,toluene,ethylbenzene, xylenes(BTEX),and total petroleum <br /> hydrocarbons as gasoline (TPHG),by EPA methods 802018015. In addition, monitoring well <br /> MW 1 was sampled for total oil and grease (TOG)by EPA method 5520 B&F. <br /> No dissolved gasoline hydrocarbon constituents were reported above detection limits in <br /> monitoring wells MWI, MW2, MW3,MW5 or MW6. Oil and grease was not reported above <br /> detection limits in MW1 (Table 2). The zero lines for total petroleum hydrocarbons in the <br /> groundwater is plotted in Figure 5. <br /> Influent and effluent samples from the pumping well (MW4) were also analyzed for WiTX, <br /> TPHG, and TOG on August 16 and September 12. The influent sample was also analyzed for <br /> TPHD on September 12. Analytical results indicate an increase in TPHG and the gasoline <br /> constituents benzene, toluene,and xylenes in the influent samples collected since the August 16 <br /> sampling round. Ethylbenzene. levels are shown to have decreased since the August 16 <br /> sampling round. The influent sample recorded nondetectable levels of TPHD and TOG. No <br /> break-through from carbon filter 1 (EFFC1)or 2(EFFC2)occurred during the sampling rounds. <br /> Laboratory analyses were performed by Applied Analytical Laboratory (DHS certification <br /> 1#1211). The analytical results are summarized in Table 2; the laboratory reports and chain-of- <br /> custody documentation are presented in Attachment 2. <br /> _ f <br /> Based on a one-year history of low to nondetectable levels of petroleum hydrocarbons recorded <br /> for samples collected from MW-2, MW-5 and MW-6, RESNA requests that the sampling <br /> schedule for these wells be changed from quarterly to annually. RESNA personnel will continue <br /> with the quarterly monitoring program which will include a report detailing system performance. <br /> Quarterly monitoring will include analysis for BTEX and TPHG from wells MW-1,MW-3,and <br /> remediation system influent(R'1W-4)and effluent. The sample from MW-I will also be analyzed <br /> for TOG. The system influent sample will not be analyzed for TPHD. We will continue to <br /> monito-system performance and adjust pumping rates as necessary, <br /> �- .. <br /> OCT 22 +nn� <br /> rv0QM923.w13 ENVIRONMENTAL HEA-LTH <br /> PERMIT/SERVICES <br />