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K L E I N F E L D E R 1 EXECUTIVE SUMMARY This report details the activities and results of the second semi-annual 2007 groundwater monitoring event conducted by Kleinfelder at the former Spreckels Sugar Plant No. 2 in Manteca, California. The activities were conducted on behalf of AKF Development Company and in accordance with Revised Waste Discharge Requirements No. R5-2003-0024. ' Groundwater monitoring was conducted on October 17 and 18, 2007. Six on-site monitoring wells (MW-1r, MW-2r, MW-6r, MW-25, MW-26, and MW-27) and one off- site monitoring well (MW-5) were sounded for depth to groundwater and sampled. ' Groundwater elevations in the monitoring wells ranged from 18.38 to 26.23 feet above mean sea level (msl). Depths to groundwater ranged from 16.58 to 23.12 feet below the tops of the well casings (BTOC). Groundwater flow direction at the site is estimated to be towards the northwest with an approximate gradient of 0.002 ft/ft. Each of the seven groundwater samples were analyzed for total dissolved solids(TDS), ' specific conductance (EC), nitrates as N, pH, total alkalinity (including alkalinity series), chloride, sulfate, calcium, and sodium. ' The results of the second semi-annual 2007 event were generally consistent with previous sampling results. The concentrations of the analytes in the monitoring locations downgradient of the former lime pond location have shown a gradual decrease over time. The concentrations in all of the downgradient wells have reached levels below the historical highs noted in the offsite upgradient well (MW-5), which have been generally stable since at least 2000. An exception to this trend is the ' concentrations of bicarbonate alkalinity in MW-25, which have been generally increasing since monitoring began, yet remain below historical highs noted in the upgradient well MW-5. The concentrations in the distant downgradient well, MW-6, have exhibited a decreasing trend in all analytes since monitoring began. Kleinfelder expects general shallow groundwater quality to continue to improve over time. {j On behalf of AKF Development Company, Kleinfelder requests that RWQCB rescind ■ Revised WDR (Order No. R5-2003-024), including the requirements for groundwater monitoring activities at the site. Following the rescinding of the WDR, all of the ' monitoring wells should be abandoned in accordance with San Joaquin County EHD regulations. Copies of this report be submitted to Mr. Mike Infurna of the San Joaquin County Environmental Health Department (EHD) and Mr. Ross Atkinson of the Central Valley Office of the State of California Regional Water Quality Control Board (RWQCB) by AKF Development for their review and consideration. Copies have been included to AKF Development for distribution. This report is subject to the limitations found in Chapter 7 of this report. 20-3978-03.MN71ST08R117 February 1,2008 0 2008 Kleinfelder Page 1 of 19