What should be done immediately after a water sample is collected?

Preserving a water sample immediately after collection is crucial for ensuring its integrity and reliability during subsequent analysis. The preservation process typically involves adding specific chemicals or adjusting certain conditions to inhibit biological activity, chemical reactions, or degradation. This is particularly important because changes in temperature, light exposure, or microbial activity can significantly alter the sample's characteristics, potentially leading to inaccurate results.

For instance, if a sample is intended for nutrient analysis, it must be preserved to prevent algal growth or nutrient consumption by microbes. Similarly, for samples meant to determine concentrations of certain contaminants, preservation techniques help avoid changes that could occur between the time of collection and analysis.

While other steps like analyzing, storing, and transporting the sample are important, they should follow the immediate preservation of the sample to maintain its integrity for accurate testing later on.