Laserfiche WebLink
1 <br />' <br />� <br />' <br />� <br />� <br />i <br />� <br />I <br />� <br />' <br />=s a resuit, turther <br />conr.racto: usin� the <br />to establish lateral <br />beloH). <br />oo:ings were perfo:med by- the <br />smalier trailer mounted drill rig <br />estent of conta.nination ISee =2 <br />Five Uorings were made to depths var�ing from :0 to 30 <br />feet deep. Two attempts at boring B-2 locatioc: were <br />made and met refusal at an old buried "concrete slab at <br />3 Ft. deep. Borin� �B-1, VW-1 and V4i-2 surror.nd the <br />tank site on the west, north and east respectivel? at <br />about five to 12 ft. away. Of the four soil samples <br />tal:en from VW-1 and VW-2 only �w-2 had a�il <br />contamination above the MCTA clean-up level and that <br />was measured at 2600 p.p.m. gas hydrocarbons at 16 ft. <br />deep. <br />2. On August 19, Seacor had their original boring <br />Contractor move in his smaller trailer-mounted drill <br />rig. Access Was qained off the propezty to the south <br />oY Mrs..James property onto her backyard to drill as <br />close as possible to the tank spill area and to her <br />garage. The first boring SB-4 was located at about <br />eight feet south of the north property line and se��en <br />east of the garaqe to provide drillers working room. <br />Although, gasoline vaPors were quite apparent at 19 <br />ft. deep the soils tested out at only 7.3 P•P•m+ 8 <br />very minor amount of petroleum hydrocarbons, almost <br />undectable in the lab. Because the soils at SB-9 were <br />impacted another boring was called for by the City at <br />the east, west centerline of the property t� determiiie <br />MTCA clean-up limits. Phe boring went to 18 ft. and <br />was tested on August 19 as clean under the h5drocarbon <br />identification method. If the SB-4 soils cou;d have <br />been tested immediately the last boring could ha•re <br />been eliminated. <br />III. Conclusions: <br />� Fror� May li, I991 when the spill was discovered until the <br />final escavations were completed on Map 20, it is believed <br />� that the majority of the contaminated soil was removed. <br />When the excavating contractor was at 15 ft. deep <br />contamination cras still at 7�00 p.p.m. even at 9 ft. into <br />hard pan. There was very little evidence of ineasuPre in <br />� the hardpan. From the time the tank was "topP °n <br />May 15, until the leak was discovered empty there was only <br />two days for the gas to migrate down 8 ft. and more totally <br />� in hardpan. The lead test, at about 25 p.p.m. from the <br />stockpile, indicates that the spill had been going on at <br />least since 1981 when fuel was changed fram leaded gas• <br />� Normal high gas concentrations can go up into the proximity <br />of 50,000 p.P.m. Since the excavation pit tesrs out at <br />21U0 p.p.m. or less, it is concluded that the major <br />� contaminents from the May 15 spill have been removed. <br />Also, the contaminated soils have been removed to the <br />extent of not endanqering buildings and adjacent property. <br />� '. <br />5 <br />