Chain of custody form, 90 Church Street, Nov 2001

NYC 9/11 Public Portal Document

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A set of up to 20 field samples plus associated laboratory QC QC Batch samples that are similar in composition (matrix) and that are processed within the same time period with the same reagent and standard lots. Consist of a pair of LCSs analyzed within the same QC batch to Duplicate Control Sample monitor precision and accuracy independent of sample matrix (I)CS) effects. This QC is performed only if required by client or when insufficient sample Is available to perform MS/MSD. A second aliquot of an environmental sample, taken from the same sample container when possible, that is processed independently with the first sample aliquot. The results are used to assess the effect of the sample matrix on the precision of the analytical Duplicate Sample (DU) process. The precision estimated using this sample is not necessarilyrepresentative of the precision for other samples in the batch. A volume of reagent water for aqueous samples or a contaminant- free solid matrix (Ottawa sand) for soil and sediment samples Laboratory Control Sample which is spiked with known amounts of representative target analytes and required surrogates. An LCS is carried through the • (LCS) entire analytical process and is used to monitor the accuracy of the analytical process independent of potential matrix effects. A field sample fortified with known quantities of target analytes that are also added to the LCS. Matrix spike duplicate is a second spike sample. MSs/MSDs are carried through the entire Matrix Spike and Matrix Spike matrix analytical process and are used to determine sample matrix effect Duplicate (MSIMSD) on accuracy of the measurement system. The accuracy and precision estimated using MS/MSD is only representative of the recision of the sample that was spiked. In A sample composed of all the reagents (in the same quantities) reagent water carried through the entire analytical process. The method blank is used to monitor the level of contamination Method Blank (MB) introduced during sample preparation steps. Organic constituents not expected to be detected In environmental media and are added to every sample and QC at a known concentration. Surrogates are used to determine the efficiency of Surrogate Spike ' 1 the sample preparation and the analytical process. Source: STL Sacramento Laboratory Quality Manual

STL Sacramento Certifications: (FLAP #1-2439), Alaska (UST-055), Arizona (#AZ00616). Arkansas, California•(NELAP # 01119CA) Hawaii, Louisiana (Al # 30612), New•3ersey (Lab ID 44005). Connecticut (#PH-0691), Florida (E87570), CA 044), South Carolina Nevada (#CA 044), New York (LAB ID 11666 serial #107407), Oregon (LAB ID (# C087), West Virginia (# (LAB ID 87014, Cert. #870140), Utah (E-168), Virginia (#00178), Washington 9930C), Wisconsin (Lab 998204680), USNAVY, USACE, USDA Foreign Plant (Permit # 37-82605), USDA • Foreign Soil (Permit # S-46613)..

NYC-WTC 000124761