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Field Report <br /> Groundwater Sampling for MW-4 <br /> Grantline Plaza <br /> Tracy, Cali rornia <br /> Jn September 27 end October 22, 1991, ROY F. WESTON, INC. (WESTON) sampled <br /> groundwater from the newly installed monitoring well MW-4 at the Grantline Plaza at 350 <br /> West Grantline Road in Tracy, California. The field work was conducted as a final <br /> confirmation sampling to evaluate if petroleum compounds and total lead were present in <br /> the groundwater downgradlen I from the former UST location and if migration had occurred <br /> along storm drain piping running north-south adjacent to the restaurant building. <br /> Prior to purging the well, measurements of total well depth and depth to water were taken. <br /> From these measurements, the standing water volume within the well casing was calculated. <br /> At this point a clear tenon bailer was lowered into and retrieved from the well. No floating <br /> I-roduct or petroleum odors were noted. The clear teflon bailer was then used to purge the <br /> four inch well of at least three well volumes. Physical parameters of pH, electrical <br /> conductivity, and temperature were collected from the purge water during the purge to <br /> ensure representative groundwater samples. End of purge values of water quality are <br /> presented in Table A-2. The clear teflon bailer was thoroughly decontaminated then used <br /> to collect the water samp'les. <br /> TABLE_A-2 <br /> Field Water Quality Measurements <br /> End of Purge Values. <br /> Well/Sample Date pH Temperature Conductivity <br /> (0 F) (unihos) <br /> MW-4 9/27/91 8.4 68.4 2080 <br /> J <br /> Ti,e bailer used to sample the well-was attached to new thin nylon line and lowered into the <br /> well by band. The bailer was filled and brought to the surface. The water in the bailer was <br /> carefully poured into laboratory prepared 40 milliliter glass bottles (TOAs) and capped with <br /> teflon lined caps. Samples were labeled xvith stick-on labels filled out in indelible ink, with <br /> the following informalion; <br /> Site name <br /> Date collected <br /> Time collected <br /> Sample I.D. <br /> Sampler's initials <br /> Analysis required <br /> Samples were sealed into ziplocl, baggies and placed with ice in an insulated chest for <br /> delivery with a chain-of-custody document to the WESTON Analyncs' laboratory in <br /> Stockton, California. This laboratory is certified by the State of California to perform the <br /> HITS'ni,i'f.1:PNP <br /> IIry44f <br />