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Quarterly Monitoring Report Page 9 Morton-Alco&Unocal Operable Units April 27,2007 <br /> ' WKA No. 6324.02 <br /> Based on the data from the environmental sample analyses and quality control information <br /> review, the data provided by the laboratory is of sufficient quality for the use intended. <br /> 6.0 SUMMARY <br /> ' 6.1 Groundwater Flow Trends <br /> ' Groundwater conditions during the first quarter of 2007 appear consistent with the existing body of <br /> data for the site. Groundwater flow beneath the site is generally toward the east and southeast. <br /> Groundwater flow is away from the deepwater ship canal. The groundwater gradient calculated <br /> during the first quarter was approximately 0.033. <br /> 6.2 Chemical Concentration Trends <br /> ' Concentrations of TPHg were detected in 5 of the 11 monitoring wells sampled, TPHmo was <br /> detected in 2 of the 11 monitoring wells sampled, and TPHd was detected in 8 of the 11 <br /> monitoring wells sampled. Concentrations of MTBE in MW5 have decreased since sampling <br /> was initiated in that well; however, only a slight decrease has occurred since August of 2005. <br /> Figures 9 and 10 show the trends in concentrations of petroleum range hydrocarbons with respect <br /> ' to groundwater elevation for wells MW6 and MW11,respectively. None of the analytes <br /> associated with EPA Method 8270C (SVOCs) were detected above laboratory detection limits <br /> during the first quarter of 2007. Dissolved arsenic, copper, lead, nickel, thallium, and zinc were <br /> ' found above laboratory detection limits in several wells. The concentrations detected of these <br /> metals appear consistent with historical occurrences. <br /> 1 <br /> 1 <br />