APPENDIX A

Definitions

The following definitions are used by the DER Quality Assurance Section and EPA.  QA Plan writers are encouraged to use these terms as defined.  If a consultant or laboratory chooses to define these terms in any other way, such definitions must be included in the associated QA Plan.

 

Analytical Set - The basic unit for analytical quality control.  Also known as sample set or analytical batch.  The analytical set is defined as samples which are analyzed (or sampled together) with the same method sequence, the same lots of reagents and with the same treatment common to all samples.  The samples must have been analyzed (or collected) within the same specified time period or in continuous sequential time periods.  Samples in each set should be of similar composition.

 

Audits - A systematic check to determine the quality of the operation of some function or activity.

            Performance Audits - Quantitative data are independently obtained for comparison with routinely obtained data in a measurement system.  Examples of these audits are EPA performance evaluation programs, commercial performance evaluation programs, split sampling program involving at least two laboratories, blind spike samples.

            Systems Audits - These are qualitative in nature and consist of an on‑site review and evaluation of a laboratory or field operations quality assurance system and physical facilities for sampling, calibration and measurements.

            Project Audits - These consist of an independent review of all sampling and analytical activity records that are associated with a specific project or event to determine if the resulting data are valid and acceptable.  Enough documentation must be available so that a reviewer is able to reconstruct the history of the samples from time of sample collection (or sample container acquisition) through final results and sample disposal.

 

Calibration - Process by which the correlation between instrument response and actual value of a measured parameter is determined. Calibration Curve:  A curve which plots the concentration of known analyte standards against the instrument response to the analyte.  Also known as a Standard Curve.

            Calibration Standard - Solutions or dilutions of a substance or material with a verifiable accuracy which are used to evaluate the sample property of an unknown sample.  In analytical terms, these standards are used to establish a calibration curve or standard instrument response factors.

            Continuing Calibration Standard - Standards that are analyzed during an analytical set to verify the accuracy of the calibration curve.

            Internal Standard - A compound having similar chemical characteristics to the compounds of interest but which is not normally found in the environment or does not interfere with the compounds of interest.  A known and specified concentration of the standard is added to each sample prior to analyses.  The concentration in the sample is based on the response of the internal standard relative to that of the calibration standard and the compound in the standard.

 

Confidence Level - The statistical probability associated with an interval of precision (or accuracy) values in a QC chart.  The values of confidence intervals are generally expressed as percent probability.  It is a commonly accepted convention that the result being tested is significant if the calculated probability is greater than 90 percent, and is highly significant if the probability is greater than 99 percent.

 

Data Quality - The totality of features and characteristics of data that bears on its ability to satisfy a given purpose.  The characteristics of major importance are accuracy, precision, completeness, representativeness, and comparability.  These characteristics are defined as follows:

            Accuracy - The degree of agreement of a measurement (or an average of measurements of the same thing), X, with an accepted reference or true value, T, usually expressed as the difference between the two values, X‑T, or the difference as a percentage of the reference or true value, 100 (X‑T)/T, and sometimes expressed as a ratio, X/T.  Accuracy is a measure of the bias in a system.  Accuracy shall be calculated according to the formulae in Section 9.2.3.2 and 9.2.3.3 of this Manual.

            Precision - A measure of mutual agreement among individual measurements of the same property, usually under prescribed similar conditions.  Precision is best expressed in terms of the standard deviation.  Various measures of precision exist depending upon the "prescribed similar conditions."  Precision shall be calculated according to the formulae listed in 9.2.3.1 of this Manual.

            Representativeness - Expresses the degree to which data accurately and precisely represent a characteristic of a population, parameter variations at a sampling point, a process condition, or an environmental condition.

            Comparability - Expresses the confidence with which one data set can be compared to another.

 

Data Quality Objectives - A set of specifications that the environmental data must meet in order to be acceptable for its intended use in a program area.  DQOs are commonly established for limits of detection and quality of data (precision, accuracy, representativeness and comparability).

 

Detection Limits - The smallest concentration/amount of an analyte of interest that can be measured with a stated probability of significance.  Detection limits must be further defined as:

            Method Detection Limit - The smallest concentration of an analyte of interest that can be measured and reported with 99 percent confidence that the concentration is greater than zero.  The MDLs are determined from the analysis of a sample in a given matrix containing the analyte at a specified level.  Determination of MDLs must be done by procedures specified in Section 9.3 of this Manual.  Equivalent procedures to determine MDLs must be approved by DER.

            Practical Quantitation Limit - The smallest concentration of an analyte of interest that can be reported with a specific degree of confidence.  PQLs shall be determined in the same way as MDLs by using the procedures specified in Section 9.2.1 of this Manual.  The standard deviation (sd) derived from the procedures will be used to calculate the PQL:  PQL = 12 sd.

            Instrument Detection Limit - The smallest amount of an analyte of interest that generates an instrument response (signal) under prescribed conditions such that the magnitude of the signal is larger than the absolute uncertainty (error) associated with it.

 

Environmental Sample - Means any sample from a natural source or source that may reasonably be expected to contribute pollution to or receive pollution from ground waters or surface waters of the state.  This includes, but is not limited to:  receiving waters; waters used to define natural background conditions; soils; sediments; industrial, domestic or municipal discharge effluents; chemical storage or handling facilities; waste disposal facilities or areas; industrial or agricultural chemical handling or application areas; surface water run‑off; and facilities for handling or applying of chemicals for weed or insect control [definition per Rule 10D‑41.101(7), F.A.C.].

            Parent Sample - Refers to a sample from which aliquots are taken for testing purposes.

            Subsample - Refers to any derivative obtained from a sample.  These include, but are not limited to:  aliquots; filtrates; digestates; eluates; fractions; extracts; reaction products; supernatants; etc.

 

Organizational Terms:

            Internal - Refers to operations, personnel, documents and protocols within the specified organization.

            External - Refers to operations, personnel, documents and protocols from a party that is separate from or outside the specified organization.

 

Parameter Group - Is defined as a group of samples that have been preserved in the same manner, prepared by similar protocols and analyzed using instruments of similar technology (also known as analyte group).  Examples of parameter groups are:

            Volatiles - (EPA methods 601, 602, and 624)

            Pesticides - (EPA methods 608, 614, 622)

            Trace Metals - (All metals except mercury)

            Nutrients - (Total Kjeldahl Nitrogen, Nitrate ⁺ Nitrite, Total Phosphorous)

 

Performance Evaluation Samples - A sample submitted for analysis whose composition and concentration are known to the submittor but unknown to the analyst.  Also known as a Blind Sample.

 

Quality Assurance - A system of activities whose purpose is to provide the producer or user of environmental data the assurance that it meets defined standards of quality with a stated level of confidence.

 

Quality Assurance Plans (QAP) - An orderly assembly of detailed and specific procedures which delineates how data of a known and accepted quality is produced.

            Comprehensive Quality Assurance Plan (CompQAP) - A QA plan that outlines all the capabilities of the specified organization, the routinely used quality control measures, the routine QA targets for precision and accuracy, and all documentation, calibration and maintenance activities that are necessary to produce data of a known and acceptable quality.

            Quality Assurance Project Plans (QAPP) - A QA plan that is written for a specific project outlining specific QA targets and data quality objectives as well as all protocols and QC measures needed to meet the project specific objectives.  A QAPP must be submitted using DER Form 17‑160.900(1).

            Research Quality Assurance Plans (RQAP) - A special type of Quality Assurance Project Plan that is generally written as a requirement of a direct contract with DER for research activities.  The specific activities are defined in section 6.0 of the Manual for Preparing QA Plans.  The content and format requirements are different from those of any other QAP.

 

Quality Control - The overall system of activities whose purpose is to document and control the quality of environmental data so that it meets the needs of the users.

 

Quality Control Measures:

      1)   Blanks - An artificial sample of an analytical matrix designed to monitor the introduction of artifacts into the system.

                        a)            Field Quality Control Blanks

1)      Field Blanks - Blanks of analyte free water that are prepared on‑site by filling appropriate sample containers with the water, adding appropriate preservatives, sealing the containers, and completing the appropriate documentation.  These blanks should be prepared during the middle to end of a sampling event by filling sample containers with water from the equipment decontamination water transport containers. They are to be treated, stored, transported, and analyzed in the same manner as the sample group for which it was intended.  These blanks may be submitted for all water parameter groups.

2)      Equipment Blank - Blanks of analyte‑free water that are prepared on‑site by pouring the equipment decontamination water through decontaminated field equipment.  Appropriate sample containers, for each analyte group must be used, preservatives added, if required, and appropriate documentation must be completed.  These blanks are to be stored, transported and analyzed with the intended parameter groups.  At least one equipment blank is required for each water and solid matrix analytical group, and must be collected at the beginning of the sampling episode.  If field decontamination is performed on-site, additional equipment blanks must be submitted for all water and solid matrix analytical groups.

3)      Trip Blank - These blanks are required for only VOC samples.  Blanks of volatile organic free water that are prepared by the organization that is providing the sample containers.  These are transported to the site with the empty VOC sample containers, and shipped to the analyzing laboratory in the same containers as the VOC samples.  They remain unopened for the entire trip.  Proper labeling and documentation must be completed.  A trip blank must be submitted for each cooler that transports VOC samples.

                        b)            Laboratory

1)      Method Blank - A blank of an appropriate analyte-free matrix that is processed (digested, extracted, etc.) and analyzed with a specified sample set.

2)      Reagent Blank - An aliquot of analyte-free water or solvent that is analyzed with a sample set.

      2)   Spiked Samples - Samples fortified to a known and validated concentration of analyte.  Percent recoveries are calculated for each compound in the spike.

a)            Field - An environmental sample fortified to a known and validated concentration in the field.  These may be submitted as blind spike(laboratory does not know they are spiked) or as identified field spikes.  The use of this QC check is not recommended by DER.

b)            Laboratory:

1)      Reagent Spikes - Samples of an appropriate analyte-free matrix (deionized water, sand, soil, etc.) that are fortified to a known and validated concentration of analyte(s) before sample preparation.

2)      Sample (Matrix) Spikes - Environmental sample selected from a set (not blanks) that are fortified to a known and validated concentration of analyte(s) before sample preparation.  The concentration of each analyte in the spiking solution should be approximately 3-5 times the level expected in the sample.

3)      Surrogate Spikes - Samples fortified with a compound having similar chemical characteristics to the compounds of interest, but which is not normally found in environmental samples.  Known concentrations of these compounds are added to all samples in the set before sample preparation.

      3)      Replicate Sample - Samples that have been collected at the same time from the same source (field replicates) or aliquots of the same sample that are prepared and analyzed at the same time (laboratory replicates).  Duplicate samples are one type of replicate sample.  The analytical results from replicates are used to determine the precision of a system.  If the concentration of analytes in the sample are below detectable limits, Duplicate Spike Samples may be used to determine precision.  Blind Replicates (Duplicates) are replicates that have been collected (field replicate) or prepared (laboratory replicate) and are submitted and analyzed as separate samples (analyst does not know they are replicates).

      4)   Quality Control Checks - Standards or samples from an independent source that are analyzed at a specified frequency.

a)            Quality Control Check Standards - Standard solutions from a source other than normal calibration standards that are certified and traceable.  These standards are used to check the accuracy of a calibration curve.

b)            Quality Control Check Samples - (also known as Reference Materials):  Samples obtained from an independent source for which the level(s) of analytes have been validated.  These samples are prepared and analyzed with a sample set of similar matrix.  If these samples have been obtained from the National Institute of Standards and Technology (formerly National Bureau of Standards), these are referred to as Standard Reference Materials.

      5)   Split Samples - Replicates of the same sample that are given to two independent laboratories for analysis.

      6)      Acceptance Criteria - The numerical limits, prescribed by the approved analytical method or internal data, by which an analytical system is verified.  These numerical limits may be generated from internal, historical data using the formula specified in Section 9.2.3.4.  Acceptance criteria shall be generated and used for all Quality Control Measures described above.  Also known as  Control Limits.

 

Sample Custody - All records and documentation required to trace a sample from point of origin through disposal after analysis.  These records must include, but are not limited to:

            1)            Field notebooks;

            2)            Field sample ID tags;

            3)            Laboratory transmittal forms (if applicable);

            4)            Laboratory sample receipt logs;

            5)            Sample extraction/preparation logs or worksheets;

            6)            Analytical (instrument) logs or worksheets;

            7)            Calibration and quality control data associated with a sample set;

            8)            Instrument maintenance logs;

            9)            Sample disposition logs; and

            10)            Final reports.

 

            Legal Chain of Custody is a special type of sample custody in which all events (i.e. possession, transport, storage, and disposal) and time intervals that are associated with a specific sample must be documented in writing.  In addition to the records described above, chain of custody records must include the following:

      1)   Sample transmittal forms or tags that have adequate spaces for the dated, original signatures of all individuals who handle the sample (or cleaned sample containers if obtained from a contracted laboratory) from time of collection (or container receipt) through laboratory delivery.     

      2)      Laboratory sample storage logs that identify date, time, and individuals who remove samples from storage. 

      3)   Secure, limited access storage areas.

 

Sample Matrix means that characteristic of an environmental or laboratory sample, associated with its physical and chemical properties, which defines how such a sample is handled when subjected to the intended analytical process.  The following samples matrices (major matrix groups), as defined below, should be used in QA plans whenever specifying data quality objectives:

            Analyte-Free Water - Water in which all analytes of interest and all positive or negative interferences are below method detection limits.  The absence of such components shall be documented by analytical records.

            Reagent Water - A sample of water which conforms to ASTM grades II, III or IV.

            Drinking Water - Includes finished (treated) or raw source water designated as potable water.  Such sources may be from surface or ground water.

            Surface Water - Includes fresh or saline waters from streams, canals, rivers, lakes, ponds, bays and estuaries (natural or manmade).

            Groundwater - Includes all waters found below ground in confined or unconfined aquifers.

            Wastewater - Includes any influent or effluent associated with domestic or industrial waste treatment facilities.

            Chemical Waste - Includes sludges and residuals from domestic or industrial wastewater processing, and liquid or solid chemicals that are no longer used for its intended purpose.

            Soil/Sediment - Surface or subsurface soils and sediments of fresh or salt water origin.

            Biological Tissue - Includes tissues of plant or animal origin.  The most common of these are shellfish, finfish and aquatic plants.

 

Sampling Kit - A set of sampling accessories that has been assembled for a specified use or project.  A Sampling Kit may include, but is not limited to:  sample containers; sampling equipment (e.g., bailers); sample preservatives, trip blanks; reagent transfer tool (e.g., disposable pipets); calibration standards; indicator papers (e.g., pH paper); or reagents.  Sampling Kits shall be subject to the documentation outlined in Section 5.0.