Types
The presence of contaminants and the characteristics of water are measured to indicate the quality of water.
Contaminants can be grouped as:
- nutrients (phosphates, nitrates)
- toxicants (metals, pesticides, herbicides)
- biologicals (algae, organic carbon)
- pathogens (bacteria, Cryptosporidium, Giardia).
The following factors affect the concentration of substances in natural water bodies:
- rainfall variability, e.g. floods and droughts
- water temperature
- evaporation rate
- soil type
- rock type
- land use.
