What is a composite sample?

A composite sample is defined as a collection of grab samples taken over a specified period of time and combined into one sample. This method reflects variations in the quality of the water over time, providing a more representative assessment than analyzing a single grab sample at one moment.

By integrating samples taken at different intervals, composite sampling is particularly useful in monitoring fluctuating conditions, such as river flow or pollutant levels, which may change throughout the day or week. This approach allows for a deeper understanding of trends and averages in water quality, making it crucial for reliable data collection in water quality assessments.

The definition of composite sampling excludes options that refer to single instances or samples taken from multiple locations without considering time, which does not capture the temporal variation necessary in environmental monitoring.