How many grab samples must be collected for monitoring specific parameters like cyanide and pH?

The correct answer highlights the regulatory requirement for environmental monitoring. For certain parameters, particularly those that can vary significantly over time or are subject to fluctuations due to different operational conditions or environmental factors, multiple grab samples are necessary to obtain a representative analysis. Collecting at least four grab samples allows for a more comprehensive understanding of the conditions being monitored and ensures that any potential variations or anomalies in the results can be captured. This approach minimizes the risk of false conclusions drawn from insufficient data and adheres to best practices in environmental compliance monitoring.

Using a single grab sample, or even two, may not provide a reliable representation of the parameter's concentration, as it may only reflect conditions at a specific moment in time. Therefore, the requirement for at least four samples enhances the integrity of the data and aligns with standard monitoring protocols.