SITE INFORMATION AND CORRESPONDENCE

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r d -s WORK PLAN FOR MW-IS AND D, AND MW-6S AND D PURPOSE The purpose of replacing MW-1 with MW-1 Shallow and MW-1 Deep is to separate the shallow sand layer at 50' and the deep sand layer at 70'. The purpose of MW-6 Shallow and MW-6 Deep is to confirm wether or not a plume is coming from the West, from an offsite source. CHARACTERIZATION OF SITE The site was affected by a leaking underground leaded gasoline storage tank, and a leaking underground Stoddard Solvent storage tank. The lifliology below ground surface is characterized by two layers of sand. The first sand layer starts ata out 45'+/-below ground surface and is about 10'thick. The second sand.layer starts at about 70'+1-below ground surface and the thickness has not yet been demonstrated since the existing boxehol s have not pierced the bottom. The direction �;� of ground water flow is Easterly. The ground water table was been dropping steadily at boutrT87 per year. The contamination plume seems to be characterized by two modes of migration,BTEX and TPI-Ig compounds have not migrated across California Str et and have stayed in the upper sand layer. 1,2-DCA is a lead scavenger in leaded gasoline. It his impacted both the shallow and the deep sand layers. It has also moved across California Street and the most Easterly monitoring wells,MW-5S, and MW-5D have the highest concentrations. SCOPE OF WORK Foothill Engineering proposes to abandon MW-1 b filling with grout and placing a concrete cap 12"bigger in diameter and 3'deep. Over drilling the well should not be necessary since MW-l has a history of non-detect. Enclosed is a summary of AW-I's analytical history. Immediately west of the existing MW-1 will be placed MW-IS and MW-1D. MW-6S and MW-6D will be placed in the North est corner of the property. The new wells will have 2" casings installed in a common 10"bore hole. The shallow casing will be placed at 55'+/-and the deep casing will be placed at 90'+/-depending on the actual location of the two sand layers as determined from drilling operations. The deep and shallow wells will have 15' screens. Soil samples from MW-I D will be collected at 20' one from the first sand layer,one from the 70' sand layer and continue on 5' increments to the new tip. Soil samples from MW-61) will be collected at 5'increments starting at 20'and continue to the bore tip. Soil samples will be collected by a 2" split spoon sampler driven into the earth. The tubes will be covered with Teflon sheeting, capped, sealed with tape and labeled. The sampl tubes will be stored on ice and delivered via chain of custody to Castle Analytical. All soil samples will be analyzed for BTEX, TPHg, Oxygenates and fuel additives and halogenated hydrocarbons. 2