Laserfiche WebLink
N <br /> April 20, 1990 <br /> l <br /> Laboratory and field handling procedures of samples are monitored by <br /> including QC samples for analysis with every submitted sample lot from <br /> a project site QC samples may include any combination of the <br /> following <br /> A Trip Blanl Used for purgeable organic compounds on)}, QC <br /> samples are collected in 40 milliliter (ml) sample vials <br /> filled in the analytical laboratory with organic-free water <br /> Trip blanks are sent to the project site, and travel with <br /> project site samples Trip blanks are not opened, and are <br /> returned from a project site with the project site samples for <br /> analysis <br /> B Field Blank Prepared in the field using organic-free <br /> water These QC samples accompany project site samples to the <br /> laboratory and are analyzed for specific chemical parameters <br /> unique to the project site where they were prepared <br /> C Duplicates Duplicated samples are collected "second <br /> samples" from a selected well and project site They are <br /> collected as either split samples or second-run samples <br /> collected from the same well <br /> D Eouiomcnt Blank Periodic QC sample collected from field <br /> equipment rinsate to verify decontamination procedures <br /> The number and types of QC samples are determined as follows <br /> F A Up to 2 wells - Trip Blank Only <br /> B 2 to 5 Wells - I Field Blank and 1 Trip Blank <br /> C 5 to 10 Wells - 1 Field blank, 1 Trip Blank, and I Duplicate <br /> t D More than 10 Wells - I Field Blank, I Trip Blank, and 1 <br /> Duplicate per each 12 wells <br /> E If sampling extends beyond one day, quality control samples <br /> will be collected for each day <br /> i <br /> Additional QC is performed through ongoing and random reviews of <br /> duplicate samples to evaluate the precision of the field sampling <br /> procedures and analytical laboratory Precision of QC data is <br /> accomplished by calculating the Relative Percent Difference (RPD) <br /> The RPD is evaluated to assess whether values are within an acceptable <br /> i <br /> range (typically ± 20% of auplicate sample) <br /> Yfloffler — ryan inc (415)783 750D Page 11 <br /> generaI and envrranmenlal conlraelars <br />