What is a field blank used for?

A field blank is specifically designed to help identify whether contaminants are introduced during the sampling process itself. By using a field blank, which consists of clean sample water transported to the sampling site and then treated in the same manner as actual samples, technicians can determine if any foreign substances are being introduced from equipment, handling, or the environment. This is crucial in maintaining the integrity of water quality data, as it ensures that the sample results accurately reflect the condition of the water source rather than the influence of sampling practices.

In contrast, assessing the quality of the water source focuses more on the actual water chemistry and biological content rather than the sampling process. Calibration of sampling equipment is an essential practice for ensuring accurate measurements, but it is distinct from the purpose of a field blank. Monitoring temperature measurements is important for specific analyses but does not relate to the purpose of ensuring that sample contamination does not occur during collection.