What are the two basic types of samples in environmental testing?

The two basic types of samples in environmental testing are grab and composite samples. Grab samples are taken at a specific point in time and reflect the conditions at that moment. They are used to measure contaminants or substances present in the environment at a particular location and time, making them useful for assessing situations where immediate data is needed.

Composite samples, on the other hand, are a mixture of several individual samples collected over a specified period or from multiple locations. This approach provides an average concentration of the analytes of interest, allowing for a more comprehensive understanding of the variability in contamination levels over time or across different sites. Composite sampling is particularly beneficial in situations where fluctuations in contaminant levels might occur, as it helps to smooth out those variations to present a clearer overall picture.

Understanding these two sampling methods is crucial in environmental testing, as they inform how data is interpreted and used for compliance and regulatory purposes.