What happens to soil samples that are not analyzed within the specific time frame?

When soil samples are not analyzed within a specific time frame, they become less reliable for accurate testing results. Over time, factors such as degradation of the sample, contamination, evaporation of volatile constituents, and changes in chemical composition can occur. This is particularly important in environmental studies where precise measurements are critical for assessing pollution levels or soil health.

Due to these potential changes, samples that are not analyzed within the designated timeframe are considered invalid for current assessments. Therefore, the conclusion is that these samples effectively "expire" in the context of their usability for accurate environmental analysis. Retesting may be needed to ensure the accuracy of any results derived from soil samples if the testing timeframe is exceeded.