If samples arrive at a laboratory past the specified holding time following collection, what must the laboratory do?

When samples arrive at a laboratory past the specified holding time following collection, the laboratory must reject the samples. This is because the integrity of water quality testing depends on analyzing samples within a specific timeframe to ensure that the results accurately reflect the conditions of the water at the time of collection.

Each type of sample has predetermined holding times based on the characteristics being tested, and exceeding that holding time could lead to changes in the samples that would invalidate the test results. Factors such as degradation of certain analytes, biological growth, or chemical alterations can occur when samples are held for too long, providing misleading or erroneous data.

If a laboratory were to accept samples collected past the holding time, it could compromise the validity of the entire sampling process. Therefore, adhering to the established protocols and rejecting samples that do not meet holding time requirements is crucial to maintaining the integrity of water quality assessments.