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W 1500. SONSIN1.Goomcn&RosATL <br /> Ms. Linda Turkatte, REHS <br /> May;26, 1.993 <br /> Page 2 <br /> Ih August 1.8,. 1989; SG&D conducted a soil vapor survey and groundwater sampling <br /> f <br /> to determine the lateral extent of the contamination and to evaluate the adjacent domestic <br /> groundwater wells for contaminants associated with diesel. Based on the survey, SG&D <br /> concluded that the.soil contamination did not.appear to have rtmig�rated`laterally outside the 4 <br /> tank excavation.m4 the upper six feet of the subsurface. Because of this. <br /> SG�iD <br /> recommended that the retraining contaminatedsoil be excavated and properly disposed of.; <br /> The data from the groundwater in the wells indicated that there was no hydrocarbon ; <br /> contamination present above regulatory action levels. <br /> { <br /> fin January:9, 1990; SG&D removed approximately 160 cubic of contaminated. <br /> Yards` <br /> soil from theexcavation. +Cont rmator soil samples taken from the walls and base of the <br /> excavaxitsn revealed itraw concentrations of toluene and xylene were present at concentrations . <br /> well below action levels. Following the completion of the excavation an additional five feet <br /> 1 <br /> of materia was over excavated to matte.sure that no;contaminated soil remained". i <br /> Because be was found in the groundwater samples but not in the onfirmatory <br /> 44011 samples from the excavation. SG&I3 concluded that the underground storage tank was' <br /> not the cause of the betizene contamination in the groundwater: <br /> s . <br /> In.a letter dated January. I7, 1990, the Health Department regucsted that Color Spot <br /> conduct a survey of groundwater wells within a 2,000 foot radius of site and that <br /> confirmation samples be collected front all groundwater wells within a Si10 foot radius of the <br /> site. Four wells were identified.for sampling,and all four contained trace amounts of <br /> benzene. 'Three contained trace amounts of toluene. Both constituents;were present in <br /> concentrations well below the drinking water standard. <br />� t <br /> .t During the week of October 8, 1990, SG&D conducted a supplemental site assessment <br /> at the site. This included the advancement of four drill holes to depths ranging from 30-9p <br /> feet below the ground surface. SG&D advanced the borings to 80 and 90 feet without <br /> finding groundwater. Finally, SG&D was able to collect a groundwater sample from oneivf <br /> the drill hales at a depth of approximately 92 feet. Because the drill rig had reached its <br /> mechanical limit, the groundwater sample was collected from inside the hollow stem auger. <br /> It was not possible to construct a proper groundwater monitoring well at the>site. Neither:the <br /> sail cuttings from the four bore hales nor the groundwater sample contained detectible <br /> doncentrations of hydrocarbon contamination..: <br /> 7 <br /> We understand that the Health Department's current position as set forth in a letter to <br /> Color Spat dated April 2, 1.993 M that Color Spot must submit a work plan providing for.. <br /> ie::anvestigadon.in the vertical extent of the contamination in the tank excavation and (2) the <br /> installation of three monitoring wells at.the site. In addition, the:Health Department has <br /> ^ FITt3i�lY1E1v1NG1CC�Lt7lt5P11xT,1R�tOSifi�L'i $ <br /> 6 <br />