Water quality in the ACT
The ACT has many different types of water bodies that support various recreational activities. Whilst these are areas of enjoyment, inherent risks to public health can arise should these waterways become contaminated by stormwater runoff.
The ACT Guidelines for Recreational Water Quality provides a framework for the management of recreational water sites within the ACT. It addresses risks such as blue-green algae and microbial pathogens.
To help safeguard the health of recreational water users, ACT Health undertakes a weekly water sampling program, between September to April each year, of Canberra’s lakes, ponds and rivers to monitor the microbial water quality of these waterways.
The sampling program includes locations along Lake Tuggeranong, Lake Ginninderra, the Murrumbidgee River Corridor, Molonglo River and Paddy’s River. The samples are delivered to the ACT Government Analytical Laboratories for analysis. All sampling results from this program are published on the Transport and City Services website. The National Capital Authority is responsible for the management of Lake Burley Griffin, including water quality monitoring for recreational use.
It is important to note that the microbial quality of recreational waters can be negatively affected after rain events due to contaminated stormwater entering the system. Water users are advised to monitor public information and locality-based signage after such events before undertaking water-based activities.
The most common adverse health effects associated with exposure to contaminated recreational waters include gastroenteritis, respiratory illness, ear infections and skin and eye problems. Should water users experience any of these symptoms after swimming in recreational water they are encouraged to contact their GP.
The ACT Chief Health Officer may advise to close a recreational water body, or part thereof, for primary or secondary contact use, if it is determined that there is a potential risk to public health.
Blue-green algae usually grow on the surface of water. Low numbers of blue-green algae are a normal part of the ecosystem in most waterways, including lakes, rivers, creeks and wetlands.
'Bloom' is the term used to describe an accumulation of algal cells to a point where they discolour the water, form scums, produce unpleasant tastes and odours and reduce the water quality. Drought and increased temperature in summer may result in an increase in visible ‘blooms’ and surface scums on waterways.
Some types of blue-green algae can produce toxins that may be harmful to humans and animals.
Exposure can occur through:
- Direct contact of skin, eyes, mouth or nose with affected water during water-based recreational activities such as swimming, diving, water-skiing, windsurfing, canoeing, rowing or other boating activities
- Breathing in fine water spray or droplets created when the surface of affected water is broken during water-based recreational activities
- Accidental swallowing of affected water
- Consumption of fish or other seafood from affected waterways
The possible health effects vary with the type of toxin and the route of exposure including:
- Direct skin contact with blue green algae toxins can cause skin and eye allergic reactions or irritation
- Accidental swallowing of affected water or consumption of food from affected water can cause symptoms of gastroenteritis, including nausea, vomiting, diarrhoea, fever and abdominal pain. In extreme cases, damage to liver cells and nerve cells can also occur
- Breathing in fine water spray or droplets from affected water during recreational water activities can cause asthma or hay fever-like symptoms
To avoid potential exposure to blue-green algae it is important to:
- Follow the advice of any information signs around affected waterways
- Avoid any recreational activities that could involve contact with affected water
- Do not eat fish or seafood from any waterway that has been affected by blue-green algae in the past 3 months
- Do not let pets drink or swim in blue-green algae affected water
- Closely monitor children and pets near affected waterways and keep them well away from the edge of the water
If you have had skin contact with affected water, immediately remove any wet clothing and wash or rinse any body part that has been in contact with the affected water. If you feel unwell, see your GP. For more information, refer to our Blue-green algae fact sheet.