Water is essential to life.
Less than three percent of Earth's total supply of water is fresh water.
Polar ice and inaccessible groundwater make up more than half of that three percent.
In the developed western world, as well as the developing world, water is becoming more polluted.
Industry is only one source of water pollution. Other sources include sewage treatment plants, households, streets and footpaths.
Individuals pollute water by littering (including cigarette butts), pouring oils down the sink, and using fertilisers and other chemicals on their gardens. These pollutants are then washed or blown into stormwater drains and local waterways.
Litter is a major contributor to visual pollution of waterways. Most litter reaches waterways through the stormwater system, washing from footpaths and streets into stormwater drains.
Water in its natural state is not always crystal clear. Decaying plants and animals, tidal flows which stir up sediment, run-off containing minerals, and sediment and nutrients are all natural, but can make water murky, cloudy, coloured or salty (saline).
In agricultural, urban and industrial settings, we have to discharge water containing some pollutants to our sewage treatment system or a waterway, because our activities rely on water to flush away waste material.
The two types of water pollution sources are point and diffuse.
A 'point source' is a discharge or outflow from an identifiable location, such as a pipe. Many industries use this method, while others discharge to the sewerage system. Oils, detergents, herbicides, insecticides, paints and solvents from households are sometimes poured down sinks and toilets, creating problems in the sewerage system and in our waterways. For more information, see Questions and answers about wastewater.
A 'diffuse' or 'non-point source' discharge doesn't come from one identifiable source. For example, run-off from agricultural and urban sources usually does not enter a waterway at one point, but enters at a number of points, including stormwater drains.
In urban areas, runoff flowing into waterways through stormwater drains carries pollutants from various sources:
- garden fertilisers, chemicals and soil from gardens
- lead, oil and tyre rubber from roads
- bacteria and micro-organisms from animal droppings
- litter items such as plastic bags, drink containers, food wrappers and cigarette butts.
Everyone can help reduce water pollution.
Agriculture, forestry, new developments and mining activities lead to land being cleared, excavated and often eroded. After rain, surface water run-off carries soil, as well as fertilisers and chemicals. This soil and chemical mix is carried by run-off water into creeks and rivers, where it can cause:
- silt to build up on creek and river beds – siltation
- excessive plant growth caused by nutrients from fertilisers – eutrophication (e.g. algal blooms)
- the death of aquatic plants and animals – poisoning.
Managing water quality depends on knowing the current, and desired, uses of particular waterways. Any use of water has the potential to pollute. Even sunscreen washed off while you're swimming can cause water pollution problems in particularly sensitive areas.
We have different water quality objectives for different water uses. Domestic water supplies for human consumption need to be of a higher quality than water used for livestock. Recreational activities such as swimming and windsurfing need water to be of a much higher quality than water used for cooling machinery in industrial processes.
Diffuse pollutant discharges are difficult to manage because they're so widespread. One solution to the problem is education programs aimed at industry and the community.
The NT EPA is committed to adopting and promoting modern and effective environmental management techniques to minimise harm to the environment.
Waste Management and Pollution Control Act 1998
The objective of the Waste Management and Pollution Control Act 1998 includes protection and where practicable to restore and enhance the quality of the Territory environment and to encourage ecologically sustainable development.
The Act also means taking responsibility for and looking after the environment for ourselves, our families and friends. The Act places a general environmental duty on everyone in the Territory not to harm the environment.
In the workplace, companies must ensure they are operating with due diligence, by taking all practical steps towards meeting their environmental responsibilities.
Compliance and enforcement
The NT EPA uses a range of enforcement methods to ensure water pollution problems are corrected and don't recur.
Prosecution is usually seen as a last resort.
It is more important to the NT EPA to work co-operatively to ensure that companies are operating in a way which doesn't cause environmental harm in the first place. However, some companies and individuals have been prosecuted for offences, leading to substantial fines.