How can we define ecological exposure points (using composite samplings)?
Composite samples must be designed to be representative of an area. Once a sample is taken that meets the sampling design requirements it can be treated the same, with respect to exposure point concentration, as the mean of discrete samples from an area. It is possible that a series of composite samples over a small area or in a short time frame would yield a more defined exposure point concentration than fewer discrete samples over a larger area or greater time frame. The resulting ecological exposure point could be compared to a benchmark for chronic exposure. Composite samples provide less information on maximum exposure concentrations, and therefore, they are not appropriate for situations where maximum exposure is used (e.g., assessing potential acute exposures, initial screening of COPCs).
