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were taken by a laboratory technician and delivered direct <br /> • to the lab by the technician, supervised by R Thorpe <br /> EXCAVATION AND SOIL SAMPLING <br /> Excavation was commenced by digging around the tank site <br /> (refilled) The area was covered with 1"--2" of degraded <br /> asphalt and silty soil The upper 1 1/2 ' appeared to be fill <br /> with root inclusions The excavation was started at the west <br /> side of the intended excavation Thewest <br /> side <br /> id wasbe g <br /> � to <br /> about 1. belnw ground level (bgl ) <br /> excavated were light brown, y , fine sand with dispersed <br /> clay from about 1 1/2 ' to 8 ' bgl , clayey brown silt to 15 ' <br /> bgl , with blue to brown clay lenses interspersed Very <br /> strong , degraded petroleum odors were noted throughout the <br /> excavation above 13 -15 ' bgl Visible oil , and a broken <br /> glass --ontazner with oily , liquid residue were found At <br /> about this point, M Infurna requested that all samples <br /> taken also be tested for Oil and Grease and TPH-D as well as <br /> TPH-G Below this depth, a clayey , silty sand with a light <br /> green color was encountered (See Figure 6 for a cross <br /> section, of excavation) Samples were taken from the West <br /> Wall , South wall , North Wall and Bottom-West (See Figure 7 <br /> for sequence , location and depth) <br /> As digging progressed, it became apparent that there was an <br /> iron staining in the soil above -15 ' bgl , getting shallnwer <br /> • as digging progressed eastward The greenish tinted, silty, <br /> clayey sand appeared to be less permeable than that above , <br /> stopping the iron staining from deeper penetration This <br /> soil layer also was dense and well compacted, digging <br /> was <br /> much harder than above As digging progressed eastward, a <br /> filled , bricked, 6 ' diameter cesspool was uncovered and dug <br /> up (Figure 6) The bricks were not cemented, spaces had been <br /> left between them for drainage and a layer of smooth rocks , <br /> 4"-5" 1, 2" were found at the bottom, a typical cesspool <br /> construction It had apparently been filled with silty top <br /> soil The rocks could have came from an old Japanese bath <br /> house ceparted by Ms Dito as having been there at one time <br /> Foundations were found for some type of structure and <br /> removed as digging progressed It became apparent that the <br /> iron staining had come from drainage from the bottom of the <br /> cesspool and had migrated northerly asshown <br /> Ton obviouures <br /> along the top of the greenish, clayey sand <br /> strong odors also did not appear below the contact between <br /> the two sand types This does not necessarily mean that no <br /> contaminates penetrated the greenish , clayey sand, , but it <br /> does mean that the penetration was limited The discovery of <br /> free O & G and the cesspool , which might have been used as a <br /> means of oil disposal , were reasons for modifying the <br /> proposed sampling plan and for slightly enlarging the dig <br /> permission was needed and was received from the owner of the <br /> • <br /> neighboring property to expand the excavation into their <br /> drive�,zy Four samples from three corners of the excavation <br /> 5 <br />