| Land use |
How contaminants enter waterways |
Potential pollutants |
| URBAN |
Stormwater drainage (pipes, drains and watercourses)
Runoff from roads, parks, gardens |
- Nutrients (fertilisers)
- Pathogens (bacteria and viruses)
- Fuel and oil from vehicles
- Tyre rubber
- Heavy metals (e.g. lead from petrol, chromium, cadmium)
Pesticides/herbicides
- Litter (e.g. paper, plastic, bottles, cardboard,
aluminium cans)
- Sediments
|
| |
Groundwater*
from areas with septic tanks
Sewage effluent
|
- Nutrients
- Chemicals (e.g. fats, soaps, detergents, solvents,
disinfectants, grease)
- Pathogens (bacteria and viruses)
|
| |
Groundwater (leachates) and surface runoff from
sanitary landfill ("tips") and liquid waste disposal
sites |
- Nutrients
- Bacteria, especially Salmonella (spread by
scavenging birds, rodents and insects)
- Toxic substances depending on nature of wastes
- Acids and alkalis
|
| |
Runoff from foreshore recreation areas and marinas,
bilge and ballast water from watercraft |
- Litter
- Nutrients (fertiliser and watercraft discharges)
- Pathogens (bacteria and viruses)
- Oil and hazardous chemicals in bilge water
- Heavy metals (anti-fouling paint)
- Oil & petrol (e.g. from boat exhausts)
|
| INDUSTRY |
Industrial waste discharges
Accidental spills
Runoff and groundwater from industrial areas
|
- Nutrients
- Chemicals depending on industrial process
(e.g. acids, alkalis, heavy metals, oil, solvents,
organic chemicals)
- Heated water
|
| AGRICULTURE AND HORTICULTURE |
Runoff, water from agricultural drains, groundwater |
- Nutrients (fertilisers & animal wastes)
- Sediment from soil erosion)
- Bacteria
- Heavy metals
- Pesticides (herbicides, fungicides, insecticides)
- Salt
|
| FORESTRY |
Runoff and groundwater |
- Herbicides/pesticides
- Sediment
|
| MINING |
Runoff from mined areas, refuse heaps and tailings ponds Mine
process or cooling water |
- Sediment
- Acid and alkaline wastes
- Toxic substances depending on process (e.g. heavy metals,
cyanide, oil, solvents)
|
*Groundwater is found
underground in the spaces between particles of rock and soil,
or in crevices and cracks in rocks. It is sometimes thought
that water flows through underground rivers or that it collects
in underground lakes however this is not the case. Groundwater
is not concentrated in streams and lakes as with surface water,
instead it exists almost everywhere underground. Certain areas
contain more water than others, these are known as aquifers and
can often be tapped by a well to produce useful quantities of water.
|