Oral Presentation Society of Environmental Toxicology and Chemistry Australasia 2021

How does pollution from new urban housing developments affect our waterways? (#138)

Claudette Kellar 1 , Kathryn Hassell 1 , Daniel MacMahon 1 , Rhys Coleman 2 , Vincent Pettigrove 1
  1. Aquatic Environmental Stress Research Group (AQUEST), RMIT University, Bundoora , Victoria , Australia
  2. Waterways and Wetlands Research, Melbourne Water, Docklands, Victoria, Australia

Fine sediments from catchments and rivers has been identified as a significant threat to environmental values in Western Port, Victoria, particularly important seagrass habitats. The largest sediment sources are thought to be from the stream bank and gully erosion. Recent evidence suggests that changes in agricultural practices and urban development are also impacting catchment sources. Associated with these sediments are pollutants which can have significant ecological impacts on the flora and fauna of the waterways and bays. Of particular concern are synthetic pyrethroids that are regularly applied in new housing estate developments. Relative to impacts from existing urban and agricultural areas, the specific aim of this project is to understand the concentrations and effects of sediment-bound pollutants generated from new urban development on waterway health.

A number of wetlands and the surrounding Quirks Creek were sampled to measure sediment-bound pollutants over a period of 18 months across a housing estate development in Officer, Victoria. Passive samplers were deployed across each of the sites on two sampling occasions. Dust samples were also collected and analysed for synthetic pyrethroids. Initial findings have shown low levels of metals across all the sampling sites. Bifenthrin (an insecticide), however, was detected in all of the wetlands at concentrations likely to cause toxic effects to aquatic invertebrates. The passive samplers found a number of herbicides, fungicides and insecticides within Quirks Creek and each of the wetlands. The risk and implications of these pollutants found within waterways will be discussed as well as potential management interventions.