Types of Analyses
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Now that you have an understanding of sample handling, let's take a look at the process of sample analysis. The WLA-RP classifies sample analysis into three broad categories:
Field/Safety Screening
Field/Safety Screening analyses are performed in the field or at an All Hazards Receipt Facility (AHRF) to screen for hazardous substances (e.g., radioactivity or chemical warfare agents) and tentatively identify the contaminants
Rapid Laboratory Analysis
Rapid Laboratory analyses are performed in the laboratory when results are needed quickly for time sensitive situations
Confirmatory Methods
Confirmatory Methods analyses are performed in the laboratory usually when reliable information on contaminant concentrations is needed (e.g., during remediation and recovery)
The ASR should work with the PRL and MSLs to develop an analytical strategy appropriate to the situation. The types of analyses selected often depend on the purpose of the monitoring (e.g., contaminant identification versus remediation) and the required data turnaround times. The analytical approach is expected to change as the incident progresses.
Analytical Approach
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The ASR and supporting laboratories (PRL and MSLs) should work together to determine an appropriate analytical approach. In doing so, they should consider information from WCIT as well as the objectives of the monitoring (e.g., initial contaminant detection, determining if clean-up goals have been met) and data turnaround times.
When monitoring objectives necessitate rapid results, laboratories should consider what steps can be taken to reduce data turnaround times. Some potential actions may include:
- Use of rapid methods
- Performing abbreviated QC
- Preparation of standards and calibration of instruments prior to sample arrival
- Reduced data review
Data that is generated quickly, without performing full QC and/or full data review, should be qualified as "Preliminary Data Pending Confirmation," and should include appropriate data qualifiers.
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Basic Field/Safety Screening
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Before a laboratory can receive samples for analysis, it will likely be necessary to perform Basic Field and Safety Screening to determine whether samples pose a hazard to laboratory staff and whether the laboratory has the capability to analyze the samples.
The purpose of field/safety screening is to: - Provide additional credible information for sample threat assessment
- Screen for agents that may pose a high acute exposure health risk (e.g., radioactive and chemical warfare agents) to protect laboratory personnel and facilities
- Tentatively identify potential contaminants
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Basic Field/Safety Screening, continued
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This screening may occur in the field or at an All Hazards Receipt Facility (AHRF), and may include the target parameters, screening techniques, and methods such as those listed in the table below.
Example Target Parameter |
Example Instrumentation |
Radiochemical |
Ludlum Model 2241-3K with probe(s) |
Free Cyanide |
Hach Model DR890 Colorimeter (reagents required) |
pH/conductivity/ORP |
Myron Ultrameter 6P |
Chlorine residual |
Hach Model DR890 Colorimeter (reagents required) |
Volatile chemicals |
ppbRAE plus photo ionization detector (PID) |
VOC (PID), CO, H2S, O2 |
MultiRAE |
Chemical Warfare Agents |
M272 Water Testing Kit |
Basic Field/Safety Screening Results
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Basic Field and Safety Screening data should be provided to the receiving laboratory as soon as it is available and prior to shipping the corresponding samples. This will allow the receiving laboratory to assess and prepare for potential hazards the samples may present upon sample receipt. A copy of the field screening information should be shipped with the samples. Sample collectors should list the Personal Protective Equipment (PPE) used on the COC form. If field screening is inadequate, incomplete, or otherwise compromised, the laboratory may require additional screening before acceptance.
Potential resources for information on field screening include:
- Water Contaminant Information Tool (WCIT)
- EPA Response Protocol Toolbox
- Sampling Guidance for Unknown Contaminants in Drinking Water
Screening analyses do not require the use of a particular procedure; however, there are available procedures for performing screening analyses, such as the All Hazard Receipt Facility (AHRF) protocol, that should be leveraged by laboratories.

Section 3.3.1
Rapid Laboratory Analyses
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During the initial phases of the incident, EPA tools such as Water Contaminant Information Tool (WCIT), may help identify rapid laboratory methods that could be used to quickly provide data (e.g., contaminant identification) and address public health concerns. These types of analyses are generally performed during the initial phases of an incident and may include reduced QC to decrease data turnaround times.
Examples
Some examples of rapid laboratory analyses include:
- 'Shake and shoot' sample preparation for extractable organics
- Headspace procedures for volatile organic analytes (VOAs)
- Immunoassays for various classes of compounds
- Real-time polymerase chain reaction (PCR) technology methods for biological agents
Rapid Methods
Rapid methods may have the following limitations:
- May not be fully validated "standard" methods
- May not provide highly accurate quantification of the contaminant
- May have known tendency to produce false positive or false negative results
- Limited availability of rapid methods for biological analytes
Laboratories should develop internal QA/QC to support their use of rapid methods and always report data as, "Preliminary Data Pending Confirmation."
Confirmatory Analyses
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As the incident progresses from initial response to remediation and recovery, confirmatory analyses performed using a consistent approach by qualified laboratories performing full QC will be needed.
A list of potential method options to conduct confirmatory analyses, found in WCIT, is as follows:
- Standardized Analytical Methods for Environmental Restoration following Homeland Security Events (SAM)
- EPA Approved Drinking Water Methods
- Other applicable EPA methods (e.g., SW-846 or 40 CFR 136 methods)
- Other methods performed by the laboratories (from Standard Methods or ASTM International)
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Confirmatory Analyses, continued
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Laboratories performing confirmatory methods should generally meet the following qualifications:
- Accredited to the standards of the National Environmental Laboratory Accreditation Program (NELAP), the NELAC Institute (TNI) standards, ISO Standard 17025, or certified under EPA's Drinking Water Certification Program (or equivalent state or regional program) for the confirmatory methods the laboratory will be performing
- Have established Standard Operating Procedures (SOPs) for their confirmatory methods
Contaminants that may be accidentally or intentionally introduced into drinking water may not fall within the suite of analytes that environmental laboratories typically monitor in drinking water. Environmental laboratories should work with other divisions of their laboratory to determine appropriate and complete sample analysis. For example, the environmental section may filter and culture biological samples, and provide the isolates to their clinical laboratory for identification.
Determining the Level of Quality Assurance/Quality Control (QA/QC)
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The level or amount of QC necessary depends on the data quality objectives and should be decided by the ASR. QC pertains to sample collection, sample analysis, as well as data reporting. Laboratories should request sample QC information during preliminary discussions with the ASR.
Level of Quality Assurance
In some cases, as when rapid turnaround and initial detection are the goal, reduced levels of QC may be acceptable. However, when quantitative results are needed to confirm that remediation efforts are successful, more extensive QC will be required. All relevant QC should be performed and documented as agreed upon by the ASR, PRL and the MSL.
Level of QA/QC, continued
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Method QA/QC requirements should be followed, depending on the monitoring objectives, and if time allows. The following is the minimum recommended QC that should be performed for rapid and confirmatory methods (confirmatory methods may require additional QC depending on use of the data and the requirements of the method) to verify that the method is performing acceptably:
Chemical
For Chemical analytes:
- Method blank
- Analytical duplicates/replicates
- Calibration verification
- Laboratory Control Sample (LCS) or Laboratory Fortified Blank (LFB)
Radiochemical
For Radiochemical analytes:
- Calibration check
- Background check
- Duplicate
- Blank
Biological
For Biological analytes:
- Positive control
- Negative control
- Blank
Member laboratories should be prepared with calibrated instruments, appropriate standards, method-specific standard analytical procedures, and qualified and trained technicians. The ASR should work with the support laboratories to determine if they have sufficient capabilities to provide the required analytical support. MSLs should provide all QC data to the PRL, in addition to a narrative description of observations, tentative identifications, and QC deviations.
Knowledge Review
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Why is field screening performed? (Select all that apply)
Knowledge Review
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Why is field screening performed? (Select all that apply)
- To avoid using more labor-intensive methods
- To provide additional credible information for sample threat assessment
- To screen for high risk agents to protect laboratory personnel and facilities
- To tentatively identify contaminants in the field which may reduce the time needed to confirm the existence of a contaminant
- All of the above
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(Select all that apply)]]>
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To avoid using more labor-intensive methods
false
To provide additional credible information for sample threat assessment
true
To screen for high risk agents to protect laboratory personnel and facilities
true
To tentatively identify contaminants in the field which may reduce the time needed to confirm the existence of a contaminant
true
All of the above
false
Yes, that is correct. The correct answers are B, C, and D. Field screening is performed for the following reasons: to provide additional credible information for sample threat assessment, to screen for high risk agents to protect laboratory personnel and facilities and tentatively identify contaminants in the field which may reduce the time needed to confirm the existence of a contaminant.
Sorry, that is incorrect. The correct answers are B, C, and D. Field screening is performed for the following reasons: to provide additional credible information for sample threat assessment, to screen for high risk agents to protect laboratory personnel and facilities and tentatively identify contaminants in the field which may reduce the time needed to confirm the existence of a contaminant.
Sorry, that is incorrect.
That is incorrect.