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As we have mentioned in previous reports, a mayor soil & ground- <br /> water plume exists to the north and west of this site Several <br /> monitoring wells have been installed in an attempt to define the <br /> limits of that contamination. Prior data reviewed by our office <br /> indicated that the plume had migrated onto the Morita property. <br /> This as supported by our data, which indicates that a mayor <br /> source of the contamination existing beneath the Morita property <br /> is coming from the west and northwest <br /> A summary of all of the laboratory analyzes of water samples <br /> taken since monitoring began an October, 1992 , is included as <br /> TABLE I . It reveals that MW-2 has generally shown the highest <br /> levels of BTEX & TPHg, with MW-1 the lowest MW-3 has measured <br /> varying low amounts of BTEX, with higher levels of TPHg Based <br /> upon maps drawn on lanes of equal concentrations of BTEX & TPHg, <br /> groundwater contamination increases to the northeast, which is <br /> the direction of groundwater flow <br /> The water table has risen an average of 2 18 ' since January, <br /> 1997, to an average depth of 37 66 , bgl, the highest level since <br /> monitoring began This rase in the water table as consistent <br /> • with other data in the Stockton area <br /> CONCLUSIONS . <br /> Based upon all of the data collected since monitoring began in <br /> October, 1992, the following conclusions appear valid- <br /> 1 Groundwater flow is relatively stable to the east/northeast, <br /> which correlates well with regional data <br /> 2 Levels of BTEX & TPHg an the water have varied widely since <br /> monitoring began, which may be due an part to the influence of <br /> the Darpetro plume to the northwest <br /> 3 . Data obtained to date indicates that the groundwater beneath <br /> this site is being impacted by an offsite source to the north and <br /> west <br /> 4 . Isoconcentration contours indicate that the levels of BTEX & <br /> TPHg are -increasing to the north and east This is a shift in <br /> direction from the prior sampling event This change may be due <br /> to fluctuations in water levels, or remediation activities being <br /> conducted offsite <br /> RECOMMENDATION <br /> . Sema-annual monitoring should continue until a significant change <br /> 2 <br />