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Lead in Victorian wetlands study

Lake Boort 

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Until 1994, recreational shooters used lead-based shot in firearms when hunting waterfowls in wetland areas of Victoria. Although lead-based shot is now banned, old lead shot remains in sediments of wetlands where hunting took place.

Lead is a metal that is toxic to humans, aquatic biota, including waterfowl and other animals and plants. There are three potential routes by which existing lead shot in wetland sediments could still pose a risk to environmental or human health:

  • lead shot in sediments can break down over time and release lead into the water and the aquatic food chain
  • lead shot sediments could be directly ingested by waterfowl and bottom-feeding fish
  • birds of prey that feed on the flesh of waterfowl containing embedded lead pellets.

Investigating lead in wetlands

EPA previously investigated the lead levels in Victorian wetlands in the late 1980s. That study concluded that use of lead shot to hunt waterfowl had not resulted in elevated concentrations of lead in water or sediments of the Western District, or Kerang and District Lakes.

In 2016, Cairn Curran community members contacted EPA to question whether lead from current or historical hunting practices was impacting the Cairn Curran Reservoir, Victoria.

EPA decided is would be useful to follow up on the 1980s study results by sampling at the same locations in 2017. Cairn Curran Reservoir was added as a sampling location in 2017.

The objectives of the 2017 investigation were to:

  • test lead levels in water and sediments of waterbodies currently and historically used for recreational waterfowl hunting
  • compare test results from 2017 against national water and sediment quality standards
  • compare the 2017 results with those reported in the 1989 EPA study
  • assess the potential for environmental and human health risks from lead in the waterbodies tested.

Testing of aquatic animals such as waterfowl, fish (including eels) and crustacea (such as yabbies) were not included in this preliminary investigation.

Lead in wetlands map

Locations sampled as part of the 2017 preliminary investigation

What were the findings?

Sediment results

The lead concentrations found in sediment samples from all nine wetlands were below the relevant sediment quality guideline values and therefore would not pose an environmental risk. The guidelines reflect what is needed to protect a healthy aquatic ecosystem.

Full results are provided in Lead in Victorian wetlands study: Preliminary investigation (EPA publication 1681).

Water results

Lead concentrations in the waters of all waterbodies tested were below the guidelines for livestock drinking water quality and recreational water quality. Lead concentrations in two waterbodies (Lake Colongulac and Lake Boort) were slightly higher than the lead guideline for drinking water. In the unlikely scenario that untreated water from these lakes is used as a regular source of drinking water, the concentrations of lead would pose a very low risk to human health.

The ecosystem protection guideline value that protects 95 per cent of ecosystem species was exceeded at four waterbodies (Lake Colongulac, Lake Colac, Lake Boort and Cairn Curran Reservoir). This indicates that in these waterbodies, the lead concentrations in water may pose a risk to ecosystem health.

Full results are provided in Lead in Victorian wetlands study: Preliminary investigation (EPA publication 1681).

Page last updated on 9 Jan 2019