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SS# 6348, Tracy <br /> QM Report, 1/31/92 <br /> In July, 1991 four monitoring wells were installed, <br /> followed by additional soil borings to delineate the volume <br /> of gasoline-contaminated soil which appears to be centered <br /> near the fill spout of the south tank. A Remedial Action <br /> Plan was prepared to respond to the estimated volumes of oil <br /> and gasoline contaminated soil. <br /> Following well development, groundwater was sampled <br /> from the four wells on July 15, 1991 and again on August 15, <br /> 1991 . Due to the fact that contamination was reported at <br /> MW-4 from the July sampling and was not detected from the <br /> August sampling, that well alone was again sampled on <br /> September 11, 1991 and no contamination was detected. These <br /> laboratory findings can be found in Table 2 . <br /> QUARTERLY MONITO ZNG ACTIVITIES <br /> Following discussion with San Joaquin County <br /> Department of Public Health personnel, MW-1 was dropped from <br /> the scheme because, based on previous sampling, it is <br /> situated in an upgradient position and no contamination <br /> appeared to have affected that location from on or off site. <br /> On December 11, 1991, MW-2 , MW- 3 , and MW-4 were <br /> monitored by taking water level measurements, examining the <br /> water for any abnormalities, and collecting water samples to <br /> be sent to a state-certified laboratory under chain-of- <br /> custody control for analysis of TPHg and STEX. <br /> Materials and instruments used for monitoring and <br /> for collecting samples were washed between each well with <br /> biodegradable soap and tap water and rinsed in distilled <br /> water. The measurement of groundwater depth was made from <br /> the top of the PVC casing using an electronic water sounder. <br /> A bailer was lowered into the well to obtain a water sample <br /> which was observed for the presence of free product, sheen, <br /> or odor. The well was bailed until at least two of the three <br /> parameters of temperature, pH, and conductivity had <br /> stabilized to within 10% of the previous reading. Water was <br /> then collected to fill three 40 ml VOA vials so that no air <br /> remained in the vial following closure with a teflon- lined <br /> cap. <br /> -2- <br />