During which test must water samples be handled with sterility precautions?

The fecal coliform test is specifically designed to detect the presence of coliform bacteria, which can indicate contamination by fecal material and potential pathogens in water. This test is critical for ensuring the safety of drinking water and the health of individuals consuming it.

Handling water samples for this test requires strict sterility precautions because non-sterile handling can introduce external bacteria that may interfere with the results, producing false positives or misleading readings. Ensuring that the samples are collected, transported, and analyzed using sterile techniques helps confirm that any detected coliform bacteria originated from the water source itself, rather than from contamination during the testing process.

In contrast, general water quality tests, turbidity tests, and chlorine residual tests do not necessitate the same level of sterility precautions. While these tests are important for assessing parameters like chemical composition and clarity of the water, they are not as sensitive to sample handling as the fecal coliform test. Thus, the focus on maintaining sterile conditions is primarily relevant to the fecal coliform analysis.