The CSM Framework: Source and Receptor

The systematic approach to understanding contamination pathways originated with Holdgate's pollution pathway concept (1979), which identified four essential characteristics common to all pollution events:

1.      The pollutant – the substance causing environmental concern

2.     The source – where the pollutant originates

3.     The transport medium – how the pollutant moves through the environment

4.    The receptor (target) – organisms, ecosystems, or property affected by the pollutant

This framework recognizes that pollution is not simply about the presence of contaminants, but about the connections between contamination sources and potential impacts.

Understanding these linkages requires consideration of emission rates, transport mechanisms, chemical and physical transformations during migration, and effects on receptors once exposure occurs (Alloway & Ayres, 1998).