Western Port

Following a survey of toxicants in 43 sites, CAPIM identified pesticides as the main threat to the Western Port environment, which informed decisions on the management and protection of the area.

ERICA the storm event sampler in Western Contour Drain.
Algal spheres to assess toxicity of waters in situ.
Tidal tank system for assessing the impacts of herbicides on mangroves.

Western Port

What was the problem?

Released in 2012, the Western Port Knowledge Review identified an important knowledge gap about the extent to which toxicants entering Western Port pose a threat to marine environments. As one of 13 high priority projects the review recommended an initial estimate of the risk of toxicants beyond discharge points be undertaken.

How did CAPIM address it?

In 2012 CAPIM completed a survey of toxicants in 43 fresh, estuarine and bay sites across Western Port. It was identified that in general most toxicants were low, however isolated areas, in the northern estuaries, elevated levels of pesticides were detected. Since this initial screening, CAPIM and Melbourne Water have been investigating the temporal and spatial occurrence of pesticides, identifying the primary sources and assessing risks to key habitats, including seagrasses and mangroves. As part of this research CAPIM have developed novel techniques to monitor, assess and source pesticide concentrations during base and storm flows, set-up specialist outdoor experimental tidal tank systems and developed in situ toxicological assays using microalgae, invertebrates and microbial communities to assess toxicant risks under both laboratory and field conditions.

What was the outcome?

This research has identified pesticides as the key toxicants posing risk to the Western Port environment. CAPIM have determined the priority pesticides, assessed the risk to floral communities, and identified the key land uses contributing to pesticide pollution as well as the reaches of highest priority in terms of contamination and biological impairment in two catchments. These outcomes are being used by Melbourne Water to make more informed decisions on the management and protection of the Western Port environment.

Further information and reports from this research are available on the Melbourne Water website: http://www.melbournewater.com.au/whatwedo/protectrivers/research/pages/western-port-environment-research.aspx

For more information on this study, please contact Dr Jackie Myers jhmyers@unimelb.edu.au.