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SAMPLING METIMMAX)GII..s USED ON THIS PH0JVCT STANDARD RWQCH INTERFACT SAMPLE: The tank removal sampling followed the atandnrd protocol for obtaining Interface camplea. These Bamplen fall into tho category of nnmplea which are known to be of primary concern to the Interested reguintory nganclao for determining if additional action will be required at n uItti and the methodology hnn boon closely defined In state and RWQCB pubilcationsp flupplemflntso and preauntntionn. Thollo specify both the ncceptablu depth and Intirni situation of Ramplo collection points, In accordance with these opacifications, Gnmple collection in executed as close an possible to the cantor line (longitudinal axis) or the tank and an a vertical axis with the fill pipe. A corresponding location in also found M the opposite end of the tank whenever standard Interface samples are being collected. Briefly, the rrmthoO consit,',a or digging up native soil from directly below the fill pipe and he corresponding opposito end of the Lank and obtaining it sample from t1lo oackfill/nntive soil interface or a short dintanco below the Interface. In the case of tanks laois than 1,000 gallons in capacity, only one sample from benenth the tank is required. A short distance line been defined by Region 2 Board engineers an not greater than twenty-four Inches bolow the backfill/native soil interface and In generally taken to be one foot below the the backfill/native soil interface. This coil is brought up In the backhoe bucket. A ahoval or trowel i;, used to cut away surface soil and backlill material which may have been included In the bucket, and the sample Is taken by pushing or driving a brass sample liner into the newly exposed soil from the designated depth and location. Additional clarifications by Region 2 Board engineers have indicated that when there is an obvious difference in the relative contamination of soil brought up from the Interface depth, then It Is the relatively more contaminated soil that should be salacted for inclusion in the sample. STOCKPILE SURVEY MODIFIRD DAAQMD PROTOCOL' This sampling follows a survey pattern, but uses a modified BAAQMD protocol for sampling stockpiles of material that have been newly removed from a tank pit excavation. This protocol calls for a discrete sample container to be collected for every 12.5 cubic yards of material. The survey Includes opposite sides of the stockpile. Strict observance of the l3AAQMD protocol (for purposes of evaluating the levels of fuel vapor likely to be discharged from a stockpile) calls for Inclusion of the surface material In the brans liner which is driven Into the pile at a right angle Ito the angle of repose) until the liner In full. Unless specifically nuked to follow the DAAQMD protocol, our personnel routinely modify the procedure to exclude the surface soil and collect co.3 from a depth of eight to eighteen Inches, While this prejudices the sample In the direction of yielding higher results than would a strict 8AAQMD sample, it Is more representative of the levels of fuel hydrocarbons --*oH-and-in--not--likely-to-mislead-the-clientorcontractor---- Into offhauling or backfilling with soil stockpiles that are relatively clean at the surface, but unacceptably contaminated through the remainder of their volume. Sampling Report 88342-C-1 ClIEVIMN 1918 SECTION FIVH/paga 8