SITE INFORMATION AND CORRESPONDENCE

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Mr. Frank Barone • - 2 - • 22 January 2008 MW-30 Work Plan The Annual 2007 Report proposes to install MW-30 about 350 feet downgradient of MW-27. It is proposed to have a screened interval between about 12 and 27 feet below ground surface, similar to MW-27 and other shallow monitoring wells in the vicinity. Exploratory borings logged by'Geomatrix in 1997 and 1999 show that an upper sand lens is expected to be intercepted between 12 and 30 feet below ground surface. Regional Water Board staff concur with the work plan to install MW-30. As stated in the Annual 2007 Report, the monitoring well will be installed by March and sampled in conjunction with the first semi-annual groundwater monitoring event, which occurs in the first quarter (January-March). Please provide the boring log and monitoring well installation diagram and a brief description of the installation in the next semi-annual monitoring report, which is due 1 June 2008. Groundwater Gradient Trends Geomatrix Consultants discovered a leak in an irrigation pipe that created a groundwater mound beneath the facility. The pipe was repaired in October 2007, but the mound interfered with the ability to establish whether phytoremediation is exerting hydraulic control over the groundwater plume. Geomatrix will provide an analysis of hydraulic capture in the fall of 2008, which will be reported in the 2008 annual monitoring report, which is due by 1 December 2008. Soil Sampling Results As presented in the Soil Sampling Report, discrete soil sampling data is obtained semi- annually from depths ranging from soil surface to five feet below ground surface. The data has been collected since 2003 and show that over time, nitrogen concentrations are declining between the soil surface and three feet deep. Between three and five feet below ground surface, the data does not show a clear trend of either decreasing or increasing concentrations of nitrogen. The cleanup goal for nitrogen in soil is 200 mg/kg, which is exceeded in about 30% of the soil samples. The data show that nitrate is not accumulating in the soil profile. The soil analyses include tests for carbamate/urea compounds, organochlorine compounds, triazines, chlorinated herbicides. Triazine compounds and chlorinated herbicides have not been detected in any soil samples since 2005. Organochlorine compounds DDT and endrin are found in the upper foot of soil at concentrations below the cleanup goals. Carbamate compounds bromacil, diuron and tebuthiuron are generally also found in the upper three feet of soil, and consistently have been below the cleanup goals. Revision to Soil Sampling Schedule Four years of semi-annual soil sampling have shown that organic constituents of concern are consistently below cleanup goals and are not increasing in the soil profile. The soil sampling program proposed in the 2001 Phytoremediation Work Plan prepared by Geomatrix Consultants may be reduced in scope and frequency. MSRMI may discontinue analyses for organic constituents in soil, and may sample annually for