Sample Analysis
Sample analysis describes the process of testing a sample to determine the presence and concentrations of certain contaminants. When designing your fish and shellfish contaminant monitoring program, it is important to consider the analytical methods and the laboratories where the samples will be analyzed.
How to Select an Analytical Method
Use consistent analytical methods throughout the fish monitoring program for repeatability and comparability across the Tribal area, state, or territory (jurisdiction). Consider technical merit, sensitivity, data quality, and cost-efficiency when selecting analytical methods. Ideally, a jurisdiction would use only one laboratory per analyte class because inter-laboratory variability will complicate interpretation if multiple laboratories are used. For additional info visit In the Lab - Analytical Methods.
Suggested Analytical Methods for Target Analytes
| Analyte Class | Analytical Method |
|---|---|
| Arsenic | EPA Method 1632A |
| Cadmium | EPA Method 200.8, Rev. 5.4, with sample preparation by SW-846 Method 3050B, or other suitable strong acid digestion procedure applicable to tissues |
| Lead | EPA Method 200.8, Rev. 5.4, with sample preparation by SW-846 Method 3050B, or other suitable strong acid digestion procedure applicable to tissues |
| Mercury* | EPA Method 1631E, with preparation by the appendix in EPA Method 1631B |
| Selenium | EPA Method 200.8, Rev. 5.4, with sample preparation by SW-846 Method 3050B, or other suitable strong acid digestion procedure applicable to tissues |
| Tributyltin | EPA Method 8323 |
*Method 1631E is used for total mercury, but the assumption is that it is all (or mostly) methylmercury. This is a conservative assumption and costs less than analyzing only for methylmercury. SW-846 Method 7473 could be used for mercury analysis, but QC limits would need to be provided by the jurisdiction since Method 7473 does not contain firm QC limits. Method 1631E (with the fish sample preparation procedure in 1631B) contains firm QC requirements and has been widely validated and used across many studies and laboratories.
| Analyte Class | Analytical Method |
|---|---|
| Amphetamine† (pharmaceutical) | EPA Method 1694 |
| Aroclors | EPA Method 1656A or SW-846 Method 8082A with extraction methods of 3540C, 3541, 3545A, or 3546 |
| BDE-47 | EPA Method 1614A |
| Dioxins/furans | EPA Method 1613B |
| Organochlorine pesticides | EPA Method 1656A or SW-846 Method 8081 with extraction methods of 3540C, 3541, 3545A, or 3546 |
| Organophosphorus pesticides | EPA Method 1657A or SW-846 Method 8141B with extraction methods of 3540C, 3541, 3545A, or 3546 |
| Oxyfluorfen‡ | |
| PAHs | SW-846 Method 8310, with sample preparation by SW-846 Method 3540C, 3541, 3545A, or 3546 |
| PCB congeners | EPA Method 1668C or EPA Method 1628 |
| PFAS | EPA Method 1633A |
†Amphetamines are controlled substances and a laboratory must have a license to possess controlled substances to perform the test.
‡There is not an EPA approved method for oxyfluorfen analysis. A research paper describes a QuEChERS multi-residue GC-MS/MS method developed for determining pesticides in tissue (Camara et al., 2020). Method SW-846 8151A does not list oxyfluorfen or tissue, but this could be used as a basis for a method for tissue analysis.
| Analyte Class | Analytical Method |
|---|---|
| Cyanotoxins (microcystins, BMAA, DABA) | For microcystins, a method using 2-methoxy-3-methyl-4-phenylbutyric acid (MMPB) procedure is under development by the EPA. |
How to Select a Laboratory for Sample Analysis
Considerations for lab selection include whether they have experience with the methods for tissue analysis and are capable of running your samples on your schedule. Jurisdictions may have varying requirements for laboratory accreditation. Some state or independent accreditation authorities do address tissue analyses, but programs vary. A reputable laboratory will have some form of quality system that governs all aspects of their work. The quality system should cover the actual analyses, quality assurance, corrective actions, sample receipt and storage, data retention policies, and staff training on technical issues as well as ethics. Most laboratories will provide a copy of their quality system documentation on request. They may ask that you not share it with other laboratories, as their procedures and policies are often considered proprietary. If a laboratory is not willing to provide you a copy, you may have to ask pointed questions about their operations. Your review of their documentation should focus on the topic areas relevant to your project and whether your specific requirements fall within their overall approach. If not, then you can tailor your implementation approach (e.g., contractual Statement of Work and Memorandum of Understanding) to address any differences.
Methods used routinely for the analyses of contaminants in fish and shellfish tissues must be documented thoroughly, preferably as formal standard operating procedures (SOPs) specific to each laboratory. Those SOPs may be based on published methods from the EPA or other recognized sources, including voluntary consensus standards bodies such as ASTM-International or other government agencies such as the U.S. Geological Survey, as implemented in the specific laboratory involved in the project.
It is important that internal data verification is performed by the laboratory before they release the results to you, the client. Their data deliverables should include a written certification statement that the data are complete, including that the QC results are compliant with the technical requirements, except as noted in the report.