Field sampling is a critical process in environmental science, ensuring that samples collected from various sites are representative and reliably reflect the presence of contaminants. Here are some valuable insights into reducing regulatory risk through successful field sampling.
Understanding the Basics
Field sampling involves collecting samples from the environment to analyze various parameters such as volatile organic analytes (VOAs), metals, anions, and many other analytes and compounds of interest. The integrity of these samples is paramount, as it directly impacts the accuracy of the analysis and subsequent regulatory decisions.
One of the key considerations in field sampling is regulations and reducing risk of non-compliance. The focal points involve protection the collection team by conducting health risk assessments, ensuring personnel wear appropriate Personal Protective Equipment (PPE), establishing emergency procedures, and recognizing hazards that require special training. For actual sample collection, proper technique, receiving criteria, chains-of-custody, sample identification, and storage are essential to minimize risk. Samples can be categorized into field samples, subsamples, extracts, and digestates.
- Field Samples: Samples collected directly from the environment, such as soil, water, air, or biological materials, taken from specific locations to represent the environmental conditions at the time of collection
- Subsamples: Smaller portions taken from a larger field sample to ensure that the sample analyzed in the laboratory is representative of the entire field sample. This process helps in obtaining more accurate and reliable analytical results
- Extracts: Solutions that result from the treatment of a sample with a solvent to separate specific components. Ex: Soil or water samples can be treated with a solvent or acid to extract contaminants like pesticides or heavy metals for further analysis.
- Digestates: Residues that remain after a sample has undergone a chemical digestion process. This process breaks down complex matrices to free the analytes of interest therefore making it easier to analyze specific elements or compounds within the sample.
Each type of sample has specific requirements and performance criteria to ensure accuracy and reliability. The National Environmental Field Activities Program (NEFAP) provides accreditation for field sampling and measurement organizations, ensuring adherence to standards such as ISO/IEC 17025.
Field sampling professionals must be aware of various standards and requirements, including the 2016 TNI Standard, DOD QSM, and EPA Drinking Water Certification Manual. Laboratories need to consider conflicting or vague requirements and use the most stringent ones to ensure compliance.
Planning Ahead
A well-thought-out sampling plan is crucial for successful field sampling. This includes understanding the goal and design of the sampling event, preparing equipment and supplies, and monitoring weather conditions for outdoor sampling. Identifying areas of risk and building risk reduction into the plan are essential steps.
Maintaining sample integrity is vital to reducing regulatory risk. This involves proper preservation, using contaminant-free chemicals, and ensuring traceability. Samples must be transported under appropriate thermal conditions and stored in a secure environment to maintain custody integrity.
Quality assurance and quality control (QA/QC) in the field are essential to ensure accurate and representative samples. This includes collecting field blanks, calibrating field instruments, training personnel, and maintaining detailed logbooks.
Sample Collection and Preservation
Proper sample collection and preservation are critical to obtaining valid results. This involves following standard operating procedures, knowing the applicable regulations, using appropriate PPE, and preserving samples with traceable reagents. Recording details such as site observations, sample collection/handling and ID numbers is essential for verification.
Transporting and Delivering Samples
Samples must be packed and transported under appropriate conditions to prevent contamination. Upon arrival at the laboratory, samples are inspected, matched against chain-of-custody documentation, and processed according to compliance program and accreditation criteria.
Successful field sampling requires meticulous planning, adherence to standards, and rigorous QA/QC procedures. By understanding the importance of sample integrity, reducing risk, and following best practices, field sampling professionals can ensure reliable and accurate results, ultimately reducing overall regulatory risk resulting in less failure and higher quality.