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Page 3 of 24 <br />SOP NUMBER 28.0 AnalVtical Data Validation <br />4.1.2 Chain-of-Custody and Sample Receipt <br />The chain of custody (COC) documentation, sample receipt, and log-in information are reviewed. <br />The analytical results received are compared against those requested on the COC form. Any COC <br />problems or discrepancies and any problems noted by the laboratory with regard to sample condition <br />upon receipt are noted in the data validation narrative along with a statement of the effect on the <br />usability of the data. <br />4.1.3 Holding Times <br />Collection-to-analysis holding times are calculated by computing the difference between the <br />sample collection date and the sample analysis date. The collection dates are found on the COC <br />and analysis dates are reported on the analysis run logs. The holding times are compared to the <br />acceptance limits contained in respective analytical methods, as applicable. Results for analyses <br />not performed within holding time limits will be qualified as estimated ("J/UJ"). If the holding <br />time is grossly exceeded (more than two times the holding time limit), the data reviewer should <br />use professional judgement to evaluate the need to reject non-detectable results. <br />A qualifier code of "HT" will be assigned to all results qualified or rejected on the basis of holding <br />times. <br />4.1.4 Method Blank (Preparation Blank) <br />The results for method blanks and calibration blanks will be reviewed. Sample results for <br />analytes detected in an associated blank at concentrations <5x the equivalent blank concentration <br />will be qualified as nondetect ("U"). For the common organic laboratory contaminants, acetone, <br />methylene chloride, 2-butanone, cyclohexane, and phthalates, sample results <1 Ox the <br />concentration in the associated blank will be qualified as nondetect ("U"). The result will be <br />qualified as nondetect at the reported concentration if the reported concentration is greater than <br />the reporting limit (>RL) or as nondetect ("U") at the reporting limit if the reported <br />concentration is <RL <br />If reported, negative blank concentrations will be evaluated for potential effects (low bias) on <br />sample data when the absolute value of the negative concentration is >RL. If the negative <br />concentration in a blank may potentially have produced more than a 25% effect on a reported <br />sample result or sample reporting limit, the associated sample result will be qualified as <br />estimated ("RUJ"). For example, if the associated blank result is -2 mg/1, the RL is 1 mg/1, and <br />the associated sample result is 5 mg/l, the sample result will be qualified as estimated because a <br />potential low bias of 2 mg/1 represents 40% of the reported concentration and the absolute value <br />of the blank concentration is >RL. <br />Continuing calibration blank samples are considered to be associated with all samples back to <br />the previously analyzed continuing calibration blank sample and up to the next continuing <br />calibration blank sample in the analytical run. <br />A qualifier code of "MB" or "CCB" will be assigned to all results qualified on the basis of <br />method blank or continuing calibration blank results, respectively. For results qualified as <br />nondetect, the bias direction is considered to be indeterminate as the reporting limit is adjusted <br />accordingly. For results qualified as estimated on the basis of blank results, the bias direction is <br />low. <br />Powertech R Squared Inc <br />Rev 28-1 JAB Attachment A <br />4/23/2007