What additional sample is included when resampling a site that was positive for total coliform?

When resampling a site that tested positive for total coliform, the practice commonly involves taking an additional sample from another nearby location. This approach aims to help determine whether the contamination is localized to the original site or if it is indicative of a broader issue affecting surrounding areas.

Collecting a sample from a nearby location provides valuable context that assists water quality analysts in understanding the scope of the contamination. It can reveal if the source of the total coliform is isolated to a specific area or if there are other sites at risk. This is essential for comprehensive risk assessment and for identifying potential sources of contamination.

In contrast, while samples from the same location or relevant controls can be important, taking a sample from another nearby location broadens the understanding of water quality issues in that region. This comparative analysis is vital in forming a complete picture of the water quality and in deciding subsequent actions to mitigate contamination.