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Focused Groundwater Investigation Work Plan Deuel Vocational Institution(DVI), Tracy, California Data Acquisition and Quality Assurance/Quality Control Method Detection Limits Annually, at a minimum, a method detection limit(MDL) study will be performed to determine the lowest concentration at which a particular analyte can be measured and reported with a 99 percent confidence that the analyte concentration is greater than zero. The MDL is determined statistically by multiplying the appropriate one-sided 99-percent t-statistic by the standard deviation obtained from at least seven analyses of a spike containing the analytes of interest, at a concentration of 3 to 5 times the estimated MDL. Method Calibration An initial calibration must be performed at the method-specified frequency. The continuing calibration will be performed at a minimum of once daily, or if the instrument exceeds calibration limits. Calibration for each target analyte will be performed,to ensure that the analytical instrumentation is functioning within the established sensitivity range.All target analytes must be present in the initial and continuing calibrations, and these calibrations must meet the acceptance criteria specified by the respective method. Calibration standards and solutions will be of known concentration and purity,to achieve the criteria necessary for validation of the analytical results. Standards used in this program will be prepared and maintained under the normal laboratory standards tracking system,which will ensure preparation, checking, documentation, storage, and disposal according to method-specified procedures and schedules. All field equipment will be calibrated according to the manufacturer's schedule or, at a minimum,before use in the field. Laboratory Method Blanks A laboratory method blank sample analysis will be performed by the laboratory daily or per analytical batch,whichever is more frequent. The laboratory blank will undergo the entire sample preparation and analysis process,to demonstrate that the laboratory/instrument is clear of background contamination and operating at acceptable detection limits. Laboratory Control Samples An LCS analysis will be performed by the laboratory daily or per analytical batch,whichever is more frequent. An LCS is a blank reagent spike containing all analytes at a specified concentration,usually in the mid-calibration range. The LCS will undergo the entire sample preparation and analysis process,to demonstrate that the method/instrument is stable and operating within acceptable accuracy limits. Surrogate Spikes Surrogate spike analyses are used to determine the efficiency of analyte recovery in organic sample preparation and analyses. Surrogate standards are added to all organic standards, samples, and blanks, and must go through the full preparation process. Surrogate spike recoveries must fall within the limits established by the project,to ensure efficiency of the method of analysis. 5-3