NSW Environmental Protection Agency NSW Government
 

Fluorescent waterways

We often receive reports by members of the public of fluorescent green waterways. The source of this can vary; however, a common cause is a chemical called fluorescein. 

Fluorescein

Fluorescein is a common water-soluble tracer dye used by plumbers and other tradies. It is an opaque, fluorescent green in colour with no odour and no oily sheen. 

It is commonly used to locate leaks and is sometimes purposely released into the environment to detect flow paths. 

It has a low ecotoxicity and typically degrades naturally in sunlight over 5–7 days, meaning it is not expected to accumulate or have detrimental effects within the environment. 

In instances where a body of water has turned fluorescent green, with no odour, no obvious source of pollution and no environmental impacts, this has likely been caused by a fluorescent dye.  

Other causes of fluorescent waterways include:

  • algal bloom – this can often be bright green in colour, however, will most likely have an odour and an oily sheen. Current algal blooms are reported at Algae Alerts NSW map – WaterNSW.
  • other chemical discharges – this could include other tracer dyes or other more toxic chemicals, and these may be differing colours. 

Other sources of fluorescent waterways can have potentially more detrimental impacts on the environment and require different incident response. When reporting an impacted waterway, the following information is useful for EPA officers to assess the suspected pollution:

  • What are the properties of the water pollution (colour, odour, opacity)?
  • Does the water have an oily sheen?
  • Are you able to identify the source of the pollution?
  • Are there any other impacts to the waterway (e.g. dead wildlife)?

Regulation of water pollution

In NSW, pollution of water is regulated through the Protection of the Environment Operations Act 1997.

The NSW EPA is the appropriate regulatory authority for water pollution relating to:

  • activities listed in schedule 1 of the POEO Act and the premises where they are carried out
  • activities carried out by a State or public authority
  • other activities in relation to which a licence regulating water pollution is issued.