 
Whenever we let something other than rainwater flow down a stormwater drain, we are adding to stormwater pollution which ends up on our beaches, contaminates our streams, kills wildlife, suffocates plants and destroys our natural environment.
The main offenders and the damage they cause are:
Fuel: Fuel can damage fish gills so they can’t breathe, as well as poisoning animals and burning plants. Fuels also contain cancer-causing agents that accumulate in fish and shellfish.
Oil: One litre of oil can taint 6000m3 and cover 100m2 of water. Oil binds to birds feathers and birds become poisoned while attempting to groom. Oil can create a surface barrier preventing oxygen from getting into the water. Toxic substances in waste oils like metals, poly-aromatic hydrocarbons, sulphur and acids can dissolve into water and cause serious harm to aquatic creatures.
Paint and Ink: These can be poisonous to creatures that come into contact with them. They also prevent light getting into the water, which makes it difficult for plants to get the sunlight/energy they need to live and for animals to find food.
Food and Drink: As food and drink rot and decay in the water, they use up all the oxygen, suffocating fish and insects. Milk spills can have serious harmful effects because decaying mild consumes huge amounts of oxygen from the water.
Detergents: Even detergents that claim to be bio-degradable or environmentally friendly can be toxic to fish and use the oxygen in the water as they break down.
Sewage: Nutrients such as phosphates, nitrates and those contained in domestic sewage promote the uncontrolled growth of plant and bacterial populations within streams. Waterways can be choked with weeds or depleted of oxygen by unnaturally high populations of micro organisms. Harmful bacteria and viruses in sewage leakages of overflows can cause serious health problems for people coming into contact with the water.
Sediment: Clay and silt are major pollutants in the Auckland Region. When they are washed off construction sites and subdivisions they smother stream beds and choke the creatures living there. Sediment is the main cause of shellfish losses in our esturaries.
Corrosives: These include battery acid, industrial chemicals, some cleaning compounds, acetic acid and concrete wastes that can damage fish, especially sensitive tissues such as eyes, gills and skin, making it impossible for juvenile creatures to survive. Adult fish and insects are burned or killed. Concrete wastes cause more fish kills than any other contaminant in Auckland every year.
Learning how to care for our environment is something we can all do and everyone in Auckland is responsible for making sure stormwater is as clean as possible. Two of our basic senses, sight and smell are incredibly powerful when combined with common sense and are capable of collecting very useful information about our streams. Conducting visual/smell tests is so simple and quick that you could consider doing it regularly, for example, each time you walk the dog or go to the dairy – you could walk via your local stream. Pollution events happen in an instant and providing early warning of such an event to the ARC Water Pollution hotline can help minimise the extent of damage and enable easier tracing of the source. If you do witness a pollution event, report it immediately to the ARC Water Pollution hotline on (09) 377 3107. Be assured that your contribution can make a difference and ultimately education of young and old alike is the key to a better future.
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