What is required when collecting a water sample for bacteriological testing?

What is required when collecting a water sample for bacteriological testing?

• A. Allow water to sit in the plumbing for at least 6 hours, and collect a first draw sample
• B. Rinse the sample bottle with chlorine solution before filling it with water
• C. Rinse the sample bottle with treated water before filling it
• D. Do not rinse the sample bottle before filling it with water. It contains sodium thiosulfate, which is required to neutralize the chlorine residual.

Answer: (D)

When collecting a water sample for bacteriological testing, it is crucial to ensure that the sample maintains its integrity and accurately represents the water quality. The correct approach involves not rinsing the sample bottle before use because it is pre-treated with sodium thiosulfate. This compound is essential as it neutralizes any chlorine residual present in the water, which could kill bacterial organisms and lead to inaccurate results. If the sample bottle were rinsed with water or any other solution, it could disrupt the balance of sodium thiosulfate, compromising the effectiveness of the bottle and threatening the validity of the test results. Thus, using the bottle as it is designed ensures that the sample remains viable for accurate bacteriological analysis.

When collecting a water sample for bacteriological testing, it is crucial to ensure that the sample maintains its integrity and accurately represents the water quality. The correct approach involves not rinsing the sample bottle before use because it is pre-treated with sodium thiosulfate. This compound is essential as it neutralizes any chlorine residual present in the water, which could kill bacterial organisms and lead to inaccurate results.

If the sample bottle were rinsed with water or any other solution, it could disrupt the balance of sodium thiosulfate, compromising the effectiveness of the bottle and threatening the validity of the test results. Thus, using the bottle as it is designed ensures that the sample remains viable for accurate bacteriological analysis.